Post-partum mammalian placental stem cells for use in the treatment of neurological or renal diseases and disorders

The present invention relates to mtfljods of exsanguinating and perfusing a placenta following expulsion from the ntenu, t.g., after birth. The present invention relata to methods of treating and culturing an isolated placenta for propagation of embryonic-like stem celle originating from foe placenta and exogenous sources. The present invention further relates to the use of a cultured placenta u abioreactor to produce biological materials or culture colls, tissues and «ganoids. The present invention also relates to stem cell collection end propagation, and in particular, to the collection of embryomotike stem cells and other multipotent stem cells from placentas. The present invention relates to embryonic-tike stem cells originating from a post-partum placenta.

2. BACKGROUND OF THE INVENTION

There is considerable interest in the identification, isolation and generation of human stem cells. Human stem cells art totipotaitial or pluripoteatial precursor cells capable of generating a variety of matnre human cell lineages. This ability serves as the basis fortbe cellular diffimtiation and specialization necessary tor organ and tissue development Recent success at transplanting such stem cells have provided new clinical tools to reconstitute and/or supplement bone nunrow after nryeloablation due to disease, exposure to toxic chemical and/or radiation. Further evidence exists that demonstrates that stem cells can be employed to «populate many, if not all, tissues and res tore physiologic and anatomic functionality. Thoapptioationofstemceltamtisiuflengmecring^othaapydolivetyand cell therapeutics is also advancing rapidly.

Many dificrent types of mammalian stem colla have been characterized. For example, cmhyonic stem cells, embryemio gem cells, adult stem cells « other committed stem cells or progenitor cells are known. Certain stem cells have not only been isolated and characterized but have also been cultured under conditions to allow differentiation to a 35 limited extent A basic problem remains, however, in that obtaining sufficient quantities

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CA 02856986 2014-07-16 and populations of human stem cells which are capable of differentiating into all cell types is near impossible. Stem cells are in critically short supply. These are important for the treatment of a wide variety of disorders, including malignancies, inborn errors of metabolism, hemoglobinopathies, and immunodéficiences, It would be highly advantageous to have a source of more embryonic stem cells.

Obtaining sufficient numbers of human stem cells has been problematic for several reasons. First, isolation of normally occurring populations of stem cells in adult tissues has been technically difficult and costly due, in part, to very limited quantity found in blood or tissue. Secondly, procurement of these cells from embryos or fetal tissue, including abortuses, has raised religious and ethical concerns. The widely held belief that the human embryo and fetus constitute independent life has prompted governmental restrictions on the use of such sources for all purposes, including medical research. Alternative sources that do not require the use of cells procured from embryonic or fetal tissue are therefore essential for further progress in the use of stem cells clinically. There are, however, few viable alternative sources of stem cells, particularly human stem cells, and thus supply is limited. Furthermore, harvesting of stem cells from alternative sources in adequate amounts for therapeutic and research purposes is generally laborious, involving, e.g., harvesting of cells or tissues from a donor subject or patient, culturing and/or propagation of cells in vitro, dissection, etc.

For example, Caplan et al. (U J. Patent No. 5,486,359 entitled ‘Human mesenchymal stem cells,” issued January 23,1996), discloses human mesenchymal stem cell (hMSC) compositions derived from the bone marrow that serve as the progenitors for mesenchymal cell lineages. Caplan et aL discloses that hMSCs are identified by specific cell surface maticos that are identified with monoclonal antibodies. Homogeneous hMSC compositions are obtained by positive selection of adherent marrow or periosteal cells that are free of markers associated with either hematopoietic cell or differentiated mesenchymal cells. These isolated mesenchymal cell populations display epitopic characteristics associated with mesenchymal stem cells, have the ability to regenerate in culture without differentiating, and have the ability to differentiate into specific mesenchymal lineages when either induced in vitro or placed invtvo at the site of damaged tissue. The drawback of such methods, however, is that they require harvesting of marrow or periosteal cells from a donor, from which the MSCs must be subsequently isolated.

Hu er el (WO 00/73421 entitled Methods of isolation, cryopreservation, and therapeutic use of human amniotic epithelial cells,” published December 7,2000) discloses human amniotic epithelial cells derived from placenta at delivery that are isolated, cultured,

-2CA 02856986 2014-07-16 cryopreserved for future use, or induced to differentiate. According to Hu et aA, a placenta is harvested immediately after delivery and the amniotic membrane separated from the chorion, &g._t by dissection. Amniotic epithelial cells are isolated from the amniotic membrane according to standard cell isolation techniques. The disclosed calls can be cultured in various media, expanded in culture, cryopreserved, or induced to differentiate. Hu eT of discloses that amniotic epithelial cells are multipotential (and possibly pluripotential), and can differentiate into epithelial tissues such as corneal surface epithelium or vaginal epithelium. The drawback of such methods, however, is frat they are labor-intensive and the yield of stem cells is very low. For example, to obtain sufficient numbers of stem cells for typical therapeutic or research purposes, amniotic epithelial cells must be first isolated from the amnion by dissection and cell separation techniques, then cultured and expanded in vitro.

Umbilical cord blood (cord blood) is a known alternative source of hematopoietic progenitor stem cells. Stem cells from cord blood are routinely cryopreserved for use in hematopoietic reconstitution, a widely used therapeutic procedure used in bone marrow and other related transplantations (see eg., Boyse et aL, US. 5,004,681, “Preservation of Fetal and Neonatal Hematopoietin Stem and Progenitor Cells of the Blood”, Boyse at al, U.S. Patent Noi 5,192,553, entitled ‘Isolation and preservation of fetal and neonatal hematopoietic stem and progenitor cells of the blood and methods of therapeutic use, issued March 9, 1993). Conventional techniques for the collection of cord blood are based on the use of a needle or cannula, which is used with the aid of gravity to drain cord blood from (Le, exsanguinate) the placenta (Boyse et aL, U.S. Patent No. 5,192,553, issued March 9,1993; Boyse et al, U.S. Patent No. 5,004,681, issued April 2,1991; Anderson, U.S. Patent No. 5,372,581, entitled Method and apparatus for placental blood collection, issued December 13,1994; Hessel et al, U.S. Patent No. 5,415,665, entitled Umbilical cord clamping, cutting, and blood collecting device and method, issued May 16,1995). The needle or cannula is usually placed in the umbilical vein and the placenta is gently massaged to aid in draining cord blood from the placenta. Thereafter, however, the drained placenta has been regarded as having no further use and has typically been discarded. A major limitation of stem cell procurement from cord blood, moreover, has been the frequently inadequate volume of cord blood obtained, resulting in insufficient cell numbers to effectively reconstitute bone marrow after transplantation.

Naughton et aL (U.S. Patent No. 5,962,325 entitled “Three-dimensioual stromal tissue cultures issued October 5,1999) discloses that fetal cells, including fibroblast-like cells and chondrocyte-progenitors, maybe obtained from umbilical card or placenta tissue

-3CA 02856986 2014-07-16 or umbilical cord blood. Naughton et al. (U.S;' Patent No. 5,962,325) discloses that such fetal stromal cells can be used to prepare a generic¹¹ stromal or cartilaginous tissue. Naughton et aL also discloses that a specific stromal tissue may be prepared by inoculating a three-dimensional matrix with fibroblasts derived from a particular individual 5 who is later to receive the cells and/or tissues grown in culture in accordance with the disclosed methods. The drawback of such an approach however, is that it is labor intensive. According to the methods disclosed in Naughton ei al, to recover fetal stromal cells from the umbilical cord or placenta requires dissection df these tissues, mincing of the tissue into pieces and disaggregation. Furthermore, to obtain adequate amounts of the fetal stromal cells from umbilical cord blood, as well as the umbilical cord and placenta, requires further expansion ex vivo.

Currently available methods for the ex vivo expansion of cell populations are also labor-intensive. For example, Emerson el aL (Emerson et al., U.S. Patent No. 6,326,198 entitled Methods and compositions for the ex vivo replication of stem cells, for the 15 optimization of hematopoietic progenitor cell cultures, and for increasing the metabolism, GM-CSF secretion and/or IL*6 secretion of human stromal cells”, issued December 4,

<img file="CA2856986C_D0001.tif" />

2001); discloses methods, and culture media conditions for er vivo culturing of human stem

According to the disclosed methods, human stem cells or progenitor cells derived from bone 20 marrow are cultured in a liquid culture medium that is replaced, preferably perfused, either continuously or periodically, at a rate of 1 ml of medium per ml of culture per about 24 to about 48 hour period. Metabolic products are removed and. depleted nutrients replenished

<img file="CA2856986C_D0002.tif" />

Kraus et aL (Kraus et aL, US. Patent No. 6,338,942, entitled “Selective expansion 25 of target ceil populations”, issued January 15,2002) discloses that a predetermined target population of cells may be selectively expanded by introducing a starting sample of cells from cord blood or peripheral blood into a growth medium, cansing cells of the target cell population to divide, and contacting foe cells in foe growth medium with a selection element comprising binding molecules with specific affinity (such as a monoclonal antibody 30 for CD34) for a predetermined population of cells (such as CD34 cells), so as to select cells of the predetermined target population from other cells in foe growth medium.

Rodgers et aL (U.S. Patent No. 6335,195 entitled “Method for promoting hematopoietic and mesenchymal cell proliferation and differentiation/' issued January 1,

2002) discloses methods for ex vivo culture of hematopoietic and mesenchymal stem cells and foe induction of lineage-specific cell proliferation and differentiation by growth in foe

-4CA 02856986 2014-07-16 presence of angiotensinogen, angiotensin I (AI),· Al analogues, Al fragments and analogues thereof angiotensin Π (AB), AB analogues, AB fragments or analogues thereof or AB AT₂type 2 receptor agonists, either alone ar in combination with other growth factors and cytokines. The stem cells are derived from bone marrow, peripheral blood or umbilical cord blood. The drawback of such methods, however, is that such ex vivo methods for inducing proliferation and differentiation of stem cells are time-consuming, as discussed above, and also result in low yields of stem cells.

Naughton et al, (U.S. Patent No. 6,022,743 entitled ‘Three-dimensional culture of pancreatic parenchymal cells cultured living stromal tissue prepared in vitro,” issued February 8,2000) discloses a tissue culture system in which stem cells or progenitor cells (e.g., stromal cells such as those derived from umbilical cord cells, placental cells, mesenchymal stem cells or fetal cells) are propagated on three-dimensional support rather than as a two-dimensional monolayer in, e.g, a culture vessel such as a flask or dish

Because of restrictions on the collection and use of stem cells, and the inadequate numbers of cells typically collected from cord blood, stem cells are in critically short supply. Stem cells have the potential to be used in the treatment of a wide variety of disorders, including malignancies, inborn errors of metabolism, hemoglobinopathies, and immunodeficiencies. There is a critical need for a readily accessible source of large numbers of human stem cells for a variety of therapeutic and other medically related purposes. The present invention addresses that need and others.

3. SUMMARY OF THE INVENTION

The present invention relates to a mammalian placenta, preferably human, which following expulsion from the uterus has been treated and cultured to produce multipotent stem cells (e-g., committed progenitor calls), embryonic-like stem cells and other biological materials. In particular, the present invention provides methods of perfusing and exsanguinating a placenta post birth. The present invention provides methods of exsanguinating and perfusing a placenta under sterile conditions for a period of at least two to greater than forty-eight hours following expulsion of the placenta from the uterus. In a preferred embodiment, the placenta is perfused with a solution containing factors to enhance the exsanguination, such as anticoagulant factors. In another embodiment the placenta is perfused with a solution containing factors to enhance the sterile conditions, such as antimicrobial and antiviral agents. In a preferred embodiment, the placenta is perfused with a solution containing growth factors. Such solutions which contains growth factors and other culture components but without anticoagulants are referred to as culture solution.

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In another preferred embodiment of the invention, the placenta is perfused to remove blood, residual cells, proteins and any other residual material, The placenta may be further processed to remove material debris. Perfusion is normally continued with an appropriate perfusate for at least two to more than twenty-four hours, hi several additional embodiments, of the invention, the placenta is perfused for at least 2,4,6,8» 10,12,14,16, 18,20, and 22 hours prior to the collection of stem cells. The perfusate collected from any of these time points may also provide a source of embryonic-like stem cells. It should be understood that the first collection of blood from the placenta is referred to as cord blood which contains predominantly CD34+ and CD38+ hematopoietic progenitor cells. Within the first twenty-four hours of post-partum perfusion, CD34+ and CD38- hematopoietic progenitor cells can be isolated from the placenta along with CD34+ and CD38- cells. After about twenty-four hours of perfusion, CD34- and CD38- cells can be isolated from the placenta along with the aforementioned cells.

The present invention relates to an isolated placenta that has been exsanguinated and perfused under sterile conditions. In a preferred embodiment, the invention provides an isolated placenta that has been exsanguinated and perfused to remove all residual cells and cultured for a period of two to twenty four hours following expulsion from the uterus. The present invention also provides an isolated placenta that has been treated and cultured to result in a viable organ capable of producing embryonic-like stem cells, progenitor cells and other biological materials.

The present inventian relates to a stem cell producing apparatus which comprises a post-partum mammalian placenta which has been exsanguinated and perfused, a means for incubating or culturing the placenta; and a means for detecting stem cells. In another embodiment, the apparatus of the invention farther comprises a collection device and/or a means for separating the collected cells. In another embodiment, the apparatus of the invention further comprises a means for monitoring and adjusting the culture conditions and collection of cells.

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<img file="CA2856986C_D0004.tif" />

embryonic-like stem cells that originate from the placenta. In. accordance with the present invention, embiyomc-like stem cells are obtained from a placenta following expulsion from the uterus. The placenta is exsanguinated and perfused for a period of at least two to twenty four hours to remove all residual cells. Tho exsanguinated placenta is then cultured under the appropriate conditions to allow for the production of endogenous stem celh originating from tiie placenta, including, but not limited to embryonic-like stem cells, and pluripotent or

-6CA 02856986 2014-07-16 multipotent stem cells, hi a preferred embodimenL the exsanguinated placenta is·, cultured in the presence of growth factors, such as PDGF and EGF.

The present invention further provides methods of treating and culturing an isolated placenta for use as a bioreactor for the propagation of endogenous stem cells originating from the placenta. The present invention provides methods of treating and culturing an isolated placenta for use as abioreactcr for the propagation of exogenous cells and biological materials, e.g._t antibodies, proteins, oligonucleotides, hormones, viruses, cytokines and enzymes. The present invention also provides propagation and collection of embryonic-like stem cells and other pluripotent and multipotent stem cells from placentas.

The cultured placenta may be used repeatedly as a bioreactor and may be cultured over a period of days, months and even years. The cultured placenta may be maintained by periodically or continuously removing a portion of a culture medium or perfusion fluid that is introduced into the system and from which the propagated cells or produced biological materials may be recovered, and replaced with fresh medium or perfusate liquid.

In another embodiment, the invention provides a method of utilizing the isolated and perfused placenta as a bioreactor in which to propagate endogenous cells, including, but not limited to, embryonic-like stem cells, progenitor cells, pluripotent ceils and multipotent cells. The endogenous cells propagated in the placental bioreactor may be collected, and/or bioactive molecules recovered from the perfusate, culture medium or from the placenta cells themselves.

<img file="CA2856986C_D0005.tif" />

In another embodiment, the invention provides a method of utilizing the isolated and perfused placenta as a bioreactor in which to propagate exogenous cells. In accordance with this embodiment, the invention relates to an isolated placenta which contains a cell not may stimulate the placenta to produce embryonic-like stem cells or wherein the engrafted cell produces signals, such a cytokines and growth factors, which may stimulate the placenta to produce stem cells. In accordance with this embodiment, the placenta xasy be engrafted with cells not placental in origin obtained from the infant associated with the placenta. In another embodiment, the placenta may be engrafted with cells not placental in origin obtained from the parents or siblings of the infant associated with the placenta. The exogenous cells propagated in the placental bioreactor maybe collected, and/or bioactive molecules recovered from the perfusate, culture medium or from the placenta cells themselves.

<img file="CA2856986C_D0006.tif" />

CA 02856986 2014-07-16

The present invention provides embryonic-like stem cells that originate from a placenta. The embryonic-like stem cells of the invention may bo characterized by measuring changes in morphology and cell surface markers using techniques such as flow cytometry and immunocytochemistry, and measuring changes in gene expression using techniques, such as PCR. In one embodiment of the invention, such embryonic-likc stem cells maybe characterized by the presence of the following cell surface markers: CD10+, CD29+-, CD34-, CD38-, CD44+, CD45-, CD54+, CD90+-, SH2+, SH3+, SH4+, SSEA3-,

SSEA4-, OCT-4+, and ABC-p+. In a preferred embodiment, such embryonic-like stem cells may be characterized by the presence of cell surface markers OCT-4+ and APC-pf.

<img file="CA2856986C_D0007.tif" />

stem cells but are not derived from the embryo. In other words, the invention encompasses

OCT-4+ and ABC-p+ cells that are undifferentiated stem cells that are isolated from postpartum perfused placenta. Such cells are as versatile (eg., pluripotent) as human embryonic stem cells. As mentioned above, a number of different pluripotent ar multipoteat stem cells can be isolated from the perftised placenta at different time points e.g., CD34+ /CD38+,

CD34+ /CD38-, and CD34-/CD38- hematopoietic cells. According to the methods of the invention, human placenta is used post-birth as the source of embryonic-like stem cells.

<img file="CA2856986C_D0008.tif" />

embryonic-like and/or multipotent or pluripotent stem cells from an extractant or perfusate of a exsanguinated placenta.

The present invention relates to pharmaceutical compositions which conquise the embryonic-like stem cells of the invention. The present invention further relates to an isolated homogenous population of human placental stem cells which has the potential to differentiate into all cell types. The invention also encompasses pharmaceutical compositions have high concentrations (or larger populations) of homogenous hematopoietic stem cells including but not limited to CD34+ /CD38- cells; and CD34-/

CD38- cells one or mote of these cell populations can be used with or as a mixture with cord blood hematopoietic cells i.&amp;_t CD34+/CD38+hematopoietic cells for transplantation and other uses.

The stem cells obtained by the methods of the invention have a multitude of uses in transplantation to treat or prevent disease. In one embodiment of the invention, they are

<img file="CA2856986C_D0009.tif" />

tissues, organs or portions thereof

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3.1. DEFINITIONS

As used herein, the tern “bioreactor** refers to an ex vivo system for propagating cells, producing or expressing biological materials and growing or culturing cells tissues, organoids, viruses, proteins, polynucleotides and microorganisms.

As used herein, the term embryonic stem cell” refers to a cell that is derived from the inner cell mass of a blastocyst (e.g., a 4- to 5-day-old human embryo) and that is pluripotent

As used herein, the term embryonic-like stem cell” refers to a cell that is not derived from the inner cell mass of a blastocyst As used herein, an embryonic-like stem cell** may also be referred to as a “placental stem cell” An embryonic-like stem cell is preferably pluripotent However, the stem cells which maybe obtained from the placenta include embryonic-like stem cells, multipotent cells, and committed progenitor cells. According to the methods of the invention, embryonic-like stem cells derived from the placenta may be collected from the isolated placenta once it has been exsanguinated and perfused for a period of time sufficient to remove residual cells.

As used herein, die term exsanguinated” or “exsanguination,” when used with respect to the placenta, refers to the removal and/or draining of substantially all cord blood from the placenta. In accordance with the present invention, exsanguination of the placenta can be achieved by, for example, but not by way of limitation, draining, gravity induced efflux, massaging, squeezing, pumping, etc.¹ In a preferred embodiment, exsanguination of tiie placenta may further bo achieved by perfusing, rinsing or flushing the placenta with a fluid that may or may not contain agents, such as anticoagulants, to aid in the exsanguination of the placenta.

As used herein, the term “perfuse” or “perfusion refers to the act of pouring or passaging a fluid over or through an organ or tissue, preferably the passage of fluid through an organ ar tissue with sufficient force or pressure to remove any residual cells, e.g., nonattached cells from the organ or tissue. As used herein, the term perfusate refers to the fluid collected following its passage through an organ or tissue. In a preferred embodiment the perfusate contains one or mare anticoagulants.

As used herein, the term “exogenous cell” refers to a “foreign” cell, Le., a heterologous cell (Le., a ‘'non-self ’ cell derivod from a source other than the placental donor) or autologous cell (Le., a “self* cell derived from theplacental donor) that is-derived from an organ or tissue other than the placenta.

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As used herein, the term “organoid ieftis to an aggregation of one or mop cell types assembled in superficial appearance or in actual structure as any organ or gland of a mammalian body, preferably the human body.

As used herein, the term “multipotent cell” refers to a cell that has the capacity to grow into any of subset of the mammalian body’s approximately 260 cell types. Unlike a pluripotent cell, a multipotent cell does not have the capacity to form, all of the cell types.

As used herein, the term phnipotent ce 11” refers to a cell that has complete differentiation versatility, Le., the capacity to grow into any of the mammalian body's approximately 260 cell types. A pluripotent cell can be self-renewing, and can remain donnant or quiescent wititin a tissue. Unlike a totipotent cell (&amp;g., a fertilized, diploid egg cell), an embryonic stem cell cannot usually form a new blastocyst

As used herein, the term progenitor cell” refera to a cell that is committed to differentiate into a specific type of cell or to form a specific type of tissue.

As used herein, the term stem cell” refers to a master cell that can reproduce indefinitely to form the specialized cells of tissues and organs. A stem cell is a developmentally pluripotent or multipotent celL A stem cell can divide to produce two daughter stem cells, or one daughter stem cell and one progenitor f transit) cell, which then proliferates into the tissue’s mature, fully formed cells.

As used herein, the term totipotent cell refers to a cell that is able to form a complete embryo (e.g., a blastocyst).

4. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a cross-sectional vjew of the cannulation of the vein and artery of a placenta to perfuse the placenta and then collect the perfusate.

Figures 2a-c are schematics showing the collection, clamping, perfusion, collection

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Figure 3 is a cross-sectional schematic of a perfused placenta in a device for use as a bioreactor.

Figure 4 is a selection scheme for sorting cells, including embryonic-like stem cells, retrieved from a perfused placenta.

5. DETAILED DESCRIPTION OF THE INVENTION

The applicant has unexpectedly discovered that the placenta after birth contains quiescent cells which can be activated if the placenta is properly processed after birth. For example, after expulsion from the womb, the placenta is exsanguinated as quickly as

-10CA 02856986 2014-07-16 possible to prevent or minimize apoptosis. Subsequently, as soon as possible after exsanguination the placenta is perfused to remove blood, residual cells, proteins, factors and any other materials present in the organ. Materials debris may also be removed from the placenta. Perfusion is normally continued with an appropriate perfusate for at least two to more than twenty-four hours. In several additional embodiments the placenta is perfused for at least 4,6,8,10,12,14,16,18,20, and 22 hours. In other words, this invention is based at least in part on the discovery that the cells of a post-partum placenta can be activated by exsanguination and perfusion for a sufficient amount of time. Therefore, the placenta can readily be used as a rich and abundant source of embryonic-like stem cells, which cells can be used for research, including drug discovery, treatment and prevention of diseases, in particular transplantation surgeries or therapies, and the generation of

<img file="CA2856986C_D0011.tif" />

committed cells, tissues and organoids.

Further, surprisingly and unexpectedly the human placental stem cells produced by the exsanguinated, perfused and/or cultured placenta are pluripotent stem cells that can

The present invention relates to methods of treating and culturing an isolated placenta for use as a bioreactor for the production and propagation of embryonic-like stem cells originating from the placenta or from exogenous sources. The present invention also relates to the use of a cultured placenta as a bioreactor to produce biological materials, including, but not limited to, antibodies, hormones, cytokines, growth factors and viruses.

The present invention also relates to methods of collecting and isolating the stem cells and biological materials from the cultured placenta.

an isolated placenta once it has been expunged from a uterus, to remove all residual cells. The invention further relates to culturing the isolated and exsanguinated placenta under the appropriate conditions to allow for the production and propagation of embryonic-like stem cells.

The present invention provides a method of extracting and recovering embryoniclike stem cells, including, but not limited to pluripotent or multipotent stem cells, from an exsanguinated human placenta. Embryonic-like stem cells have characteristics of embryonic stem cells but are not derived from the embryo. Such cells are as versatile (e.g., pluripotent) as human embryonic stem cells. According to the methods of the invention, human placenta is used post-birth as the source of embryonic-like stem cells.

According to the methods of the invention embryonic-like stem cells are extracted from a drained placenta by means of a perfusion technique that utilizes either or both of the

-11CA 02856986 2014-07-16 umbilical artery and umbilical vein. The placenta is preferably drained by exsanguination and collection of residual blood (e.g., residual umbilical cord blood). The drained placenta is then processed in such a manner as to establish an ex vivo, natural bioreactor environment in which resident embryonic-like stem ceils within the parenchyma and extravascular space 5 are recruited. The embryonic-like stem cells migrate into the drained, empty microcirculation where, according to the methods of the invention, they are collected, preferably by washing into a collecting vessel by perfusion.

5.1. METHODS OF ISOLATING AND CULTURING PLACENTA

5,1.1, Pretreatment of Placenta

According to the methods of the invention, a human placenta is recovered shortly after its expulsion after birth and, in certain embodiments, the cord blood in the placenta is recovered. In certain embodiments, the placenta is subjected to a conventional cord blood recovery process. Such cord blood recovery may be obtained commercially, e.g., LifeBank 15 Inc., Cedar Knolls, N.J., ViaCord, Cord Blood Registry and Ciyocell. The cord blood can be drained shortly after expulsion of the placenta.

Postpartum the placenta is drained of cord blood. The placenta stored may be under sterile conditions and at either room temperature or at a temperature of 5 to 25 “C 20 (centigrade). The placenta may be stored for a period of longer than forty eight hours, and preferably for a period of four to twenty-four hours prior to perfusing the placenta to remove any residual cord blood.

Typically, a placenta is transported from the delivery or birthing room to another location, e.g., a laboratory, for recovery of the cord blood and/or drainage and perfusion. 25 The placenta is preferably transported in a sterile, thermally insulated transport device (maintaining the temperature of the placenta between 20-28’C), for example, by placing the placenta, with clamped proximal umbilical cord, in a sterile zip-lock plastic bag, which is then placed in an insulated container, as shown in Figures 2a-e. Preferably, the placenta is delivered to the laboratory four to twenty-four hours following delivery.

The placenta is preferably recovered after expulsion under aseptic conditions, and stored in an anticoagulant solution at a temperature of 5 to 25°C (centigrade). Suitable anticoagulant solutions are well known in the art For example, a solution of heparin or warfarin sodium can be used. In a preferred embodiment, the anticoagulant solution comprises a solution of heparin (1½ w/w in 1:1000 solution). The drained placenta is preferably stored for no more than 36 hours before the embryonic-like stem cells are

-12CA 02856986 2014-07-16 collected. The solution which is used to perfuse the placenta to remove residual cells can be the same solution used to perfuse and culture the placenta for the recovery of stem cells. Any of these perfusates may be collected and used as a source of embryonic-like stem cells.

In certain embodiments, the proximal umbilical cord is clamped, preferably within 4-5 cm (centimeter) of the insertion into the placental disc prior to cord blood recovery, hi other embodiments, the proximal umbilical cord is clamped after cord blood recovery but prior to further processing of the placenta.

Conventional techniques for the collection of cord blood may be used. Typically a needle or cannula is used, with the aid of gravity, to drain cord blood from (ί,β., exsanguinate) the placenta (Bayse et al, U.S. Patent No. 5,192,553, issued March 9,1993; Boyse et aL, U.S. Patent No. 5,004,681, issued April 2,1991; Anderson, U.S. Patent No. 5,372,581, entitled Method and apparatus for placental blood collection, issued December 13,1994; Hessel et al, U.S. Patent No. 5,415,665, entitled Umbilical cord clamping, cutting, and blood collecting device and method, issued May 16,1995). lhe needle or cannula is usually placed in the umbilical vein and the placenta is gently massaged to aid in draining cord blood from the placenta.

In a preferred embodiment, the placenta is recovered from a patient by informed consent and a complete medical history of the patient prior to, during and after pregnancy is also taken and is associated with the placenta. These medical records can be used to coordinate subsequent use of the placenta or the stem éells harvested therefrom. For example, the human placental stem cells can then easily be used for personalized medicine for the infant in question, the parents, siblings or other relatives. Indeed, the human placental stem cells are more versatile than cord blood. However, it should be noted that

<img file="CA2856986C_D0012.tif" />

exsanguinated, perfused and/or cultured placenta to cord blood from the same or different placenta and umbilical cord. The resulting cord blood will have an increased concentration/population of human stem cells and thereby is more usefhl for transplantation eg. for bone marrow transplantations.

5.1.2. Exsanguination of Placenta and Removal of Residual Cells

The invention provides a method for recovery of stem or progenitor cells, including, but not limited to embryonic-like stem cells, from a placenta that is exsanguinated, Le., completely drained of the cord blood remaining after birth and/or a conventional cord blood recovery procedure. Accordmgtotheinethodsoftheinvention,theplaceniais exsanguinated and perfused with a suitable aqueous perfusion fluid, such as an aqueous

-13CA 02856986 2014-07-16 isotonic fluid in which an anticoagulant (eg;; heparin, warfarin sodium) is dissolved. Such aqueous isotonic fluids for perfusion are well known in the art, and include, e.g., a 0.9 N sodium chloride solution. The perfusion fluid preferably comprises the anticoagulant, such as heparin or warfarin sodium, at a concentration that is sufficient to prevent the formation 5 of dots of any residual cord blood. In a specific embodim^ a concentration of from 1 to

100 units of heparin is employed, prefcrably-a concentration of 1 to 10 units of heparin per ml is employed. In one embodiment, apoptosis inhibitors, such as free radical scavengers, in particular oxygen free radical scavengers, can be used during and immediately after exsanguination and then these agents can be washed from the placenta, hi accordance with 10 this embodiment of the invention, the isolated placenta maybe stored under hypothermic conditions in order to prevent or inhibit apoptosis.

According to the methods of the invention, the placenta is exsanguinated by passage of the perfusion fluid through either or both of the umbilical artery and umbilical vein, using a gravity flow into the placenta. The placenta is preferably oriented (eg., suspended) in 15 such a manner that the umbilical artery and umbilical vein are located at the highest point of tin placenta. In a preferred embodiment, the umbilical artery and the umbilical vein are connected simultaneously, as shown in Figure 1, to a pipette that is connected via a flexible connector to a reservoir of the perfiision fluid. The perfusion fluid is passed into the umbilical vein and artery and collected in a suitable open vessel from the surface of the 20 placenta that was attached to the uterus of the mother during gestation, lhe perfusion fluid may also be introduced through the umbilical cord opening and allowed to flow ar perculate out of openings in the wall of the placenta which interfaced with the maternal uterine wall.

In a preferred embodiment, the proximal umbilical cord is clamped during perfusion, and more preferably, is clamped within 4-5 cm (centimeter) of the cord’s 25 insertion into the placental disc.

In one embodiment, a sufficient amount of p erfusion fluid is used that will result in removal of all residual cord blood and subsequent collection or recovery of placental cells, including but not limited to embryonic-like stem cells and progenitor cells, that remain in the placenta after removal of the cord blood.

It has been observed that when perfusion fluid is first collected from a placenta during the exsanguination process, the fluid is colored with residual red blood cells of the cord blood. The perfusion fluid tends to become clearer as perfusion proceeds and the residual cord blood cells are washed out of the placenta. Generally from 30 to 100 ml (milliliter) of perfusion fluid is adequate to exsanguinate the placenta and to recover an

-14CA 02856986 2014-07-16 initial population of embryonic-like cells from the placenta, but more or less perfusion fluid may be used depending on the observed results.

5.1.3. Culturing Placenta

After exsanguination and a sufficient time of perfusion of the placenta, the embryonic-like stem cells are observed to migrate into the exsanguinated and perfused microcirculation of the placenta where, according to the methods of the invention, they are collected, preferably by washing into a collecting vessel by perfusion. Perfusing the isolated placenta not only serves to remove residual cord blood but also provide the placenta with the appropriate nutrients, including oxygen. The placenta may be cultivated and perfused with a similar solution which was used to remove the residual cord blood cells, preferably, without the addition of anticoagulant agents.

hi certain embodiments of the invention, die drained, exsanguinated placenta is cultured as a bioreactor, i.e., an ex vivo system for propagating cells or producing biological materials. The number of propagated cells or level of biological material produced in the placental bioreactor is maintained in a continuous state of balanced growth by periodically or continuously removing a portion of a culture medium or perfusion fluid that is introduced into the placental bioreactor, and from which the propagated cells or the produced biological materials may be recovered. Fresh medium or perfusion fluid is introduced at the same rate or in the same amount.

The number and type of cells propagated may easily be monitored by measuring changes in morphology and cell surface markers using standard cell detection techniques such as flow cytometry, cell sorting, immunocytochemistry (e.g., staining with tissue specific or cell-marker specific antibodies) fluorescence activated cell sorting (FACS), magnetic activated cell sorting (MACS), by examination of the morphology of cells using light or confocal microscopy, or by measuring changes in gene expression using techniques well known in the art, such as PCR. and gene expression profiling.

In one embodiment, the cells may be sorted using a fluorescence activated cell sorter (FACS). Fluorescence activated cell sorting (FACS) is a well-known method for separating particles, including cells, based on the fluorescent properties of the particles (Kamarch, 1987, Methods Enzymol, 151:150-165). Laser excitation of fluorescent moieties in the individual particles results in a small electrical charge allowing electromagnetic separation of positive and negative particles from a mixture. In one embodiment, cell surface marker-specific antibodies or ligand» are labeled with distinct fluorescent labels. Cells are processed through the cell sorter, allowing separation of cells based on them ability

-15CA 02856986 2014-07-16 to bind to the antibodies used. FACS sorted particles may be directly deposited.-into individual wells of 96-well or 384-well plates to facilitate separation and cloning.

In another embodiment, magnetic beads can be used to separate cells. The cells may be sorted using a magnetic activated cell sorting (MACS) technique, a method for separating particles based on their ability to bind magnetic beads (0.5-100pm diameter). A variety of useful modifications can be performed on the magnetic microspheres, including covalent addition of antibody which specifically recognizes a cell-solid phase surface molecule or hapten. A magnetic field is then applied, to physically manipulate the selected beads. The beads axe then mixed with the cells to allow binding. Cells are then passed through a magnetic field to separate out cells having cell surface markers. These cells can then isolated and re-mixed with magnetic beads coupled to an antibody against additional cell surface markers. The cells are again passed through a magnetic field, isolating cells that bound both, the antibodies. Such cells can then be diluted into separate dishes, such as microtiter dishes for clonal isolation.

In preferred embodiments, the placenta to be used as a bioreactor is exsanguinated and washed under sterile conditions so that any adherent coagulated and non-adherent cellular contaminants are removed. The placenta is then cultured or cultivated under aseptic conditions in a container or other suitable vessel, and perfused with perfusate solution (ag., a normal saline solution such as phosphate buffered saline (“PBS)) with or without an anticoagulant (e.g., heparin, warfarin sodium, coumarin, bishydroxycoumarin), and/or with or without an antimicrobial agent (eg., β-mercaptoethanol (O.lmM); antibiotics such as streptomycin (eg., at 40-100 pg/ml), penicillin (eg., at 40U/ml), amphotericin B (eg, at 0.5 pg/ml).

The effluent perfusate comprises both circulated perfusate, which has flowed through the placental circulation, and extravasated perfusate, which, exudes from or passes through tiie walls of the blood vessels into the surrounding tissues of the placenta. The effluent perfusate is collected, and preferably, both the circulated and extravasated perfusates are collected, preferably in a sterile receptacle. Alterations in the conditions in which the placenta is maintained and tiie nature of the perfusate can be made to modulate 30 the volume and composition of the effluent perfusate.

Cell types are then isolated from the collected perfusate by employing techniques known by those skilled in the art, such as for example, but not limited to density gradient centrifugation, magnet cell separation, flow cytometry, affinity cell separation or differential adhesion techniques.

-16CA 02856986 2014-07-16 lu one embodimerrt, a placenta is placed in a sterile basin and washed with 500 ml of phosphate-buficred normal saline. The wash fluid is then discarded. The umbilical vein is then cannulated with a cannula, e.g., a TEFLON® or plastic cannula, that is connected to a sterile connection apparatus, such as sterile tubing. The sterile connection apparatus is 5' connected to a perfusion manifold, as shown in Figure 3. The container containing the placenta is then covered and the placenta is maintained at room temperature (20-25*C) tor a desired period of time, preferably from 2 to 24 hours, and preferably, no longer than 48 hours. The placenta may be perfused continually, with equal volumes of perfusate introduced and effluent perfusate removed or collected. Alternatively, the placenta may be 10 perfused periodically, eg., at every 2 hours or at 4,8,12, and 24 hours, with a volume of perfusate, eg., 100 ml of perfusate (sterile normal saline supplemented with or without 1000 u/1 heparin and/or EDTA and/or CPDA (creatine phosphate dextrose)). In the case of periodic perfusion, preferably equal volumes of perfusate are introduced and removed from die culture environment of die placenta, so that a stable volume of perfusate bathes die placenta at all times.

The effluent perfusate that escapes the placenta, eg., at the opposite surface of the placenta, is collected and processed to isolate embryonic-like stem cells, progenitor cells or other cells of interest

Various media may be used as perfusion fluid for culturing or cultivating the placenta, such as DMBM, F-12, M199, RPMI, Fisher's, Iscore's, McCoy's and combinations thereof supplemented with fetal bovine serum (FBS), whole human serum (WHS), ar human umbilical cord serum collected at the time of delivery of the placenta. The same

<img file="CA2856986C_D0013.tif" />

culture or cultivate the placenta, without die addition of anticoagulant agents.

h certain embodiments, the embiyonio-like stem cells are induced to propagate in die placenta bioreactor by introduction of nutrients, hormones, vitamins, growth factors, ar any combination thereof into the perfusion solution. Serum and other growth factors may be added to the propagation perfusion solution or medium. Growth factors axe usually proteins and include, but are not limited to: cytokines, lymphokines, interférons, colony stimulating factors (CSF’s), interférons, chemokines, and interleukins. Other growth factors that may be used include recombinant human hematopoietic growth factors including ligands, stem cell factors, thrombopoeitm (Tpo), granulocyte colony-stimulating factor (GCSF), leukemia inhibitory factor, basic fibroblast growth factor, placenta derived growth factor and epidermal growth factor.

-17CA 02856986 2014-07-16

The growth factors introduced into the perfusion solution can stimulate'the propagation of undifferentiated embryonic-like stem cells, committed progenitor cells, or differentiated cells (e.g., differentiated hematopoietic cells). The growth factors can stimulate the production of biological materials and bioactive molecules including, but not limited to, immunoglobulins, hormones, enzymes or growth factors as previously described. In onb embodiment of the invention, the placenta is used as a bioreactor for propagating endogenous cells (Le., cells that originate from the placenta), including but not limited to, various kinds of pluripotent and/or totipotent embryonic-like stem cells and lymphocytes. To use the placenta as a bioreactor, it may be cultured for varying periods of time under sterile conditions by perfusion with perfusate solution as disclosed herein, hi specific embodiments, the placenta is cultured for at least 12,24,36, or 48 hours, or for 3-5 days, 6-10 days, or for one to two weeks, hi a preferred embodiment, the placenta is cultured for 48 hours. The cultured placenta should be “fed” periodically to remove the spent media, depopulate released cells, and add fresh media. The cultured placenta should be stored under sterile conditions to reduce the possibility of contamination, and maintained under intermittent and periodic pressurization to create conditions that maintain an adequate supply of nutrients to the cells of the placenta. It should be recognized that the perfusing

<img file="CA2856986C_D0014.tif" />

increased capacity.

In another embodiment, the placenta is processed to remove all endogenous proliferating cells, such as embryonic-like stem cells, and to allow foreign (Le., exogenous) cells to be introduced and propagated in the environment of the perfused placenta. The invention contemplates a large variety of stem or progenitor cells that can be cultured in the placental bioreactor, including, but not limited to, embryonic-like stem cells, mesenchymal stem cells, stromal cells, endothelial cells, hepatocytes, kératinocytes, and stem or progenitor cells for a particular cell type, tissue or organ, including but not Ibnifed to neurons, myelin, muscle, blood, bone marrow, skin, heart, connective tissue, lung, kidney, Ever, and pancreas (e.g., pancreatic islet cells).

Sources of mesenchymal stem cells include bone marrow, embryonic yolk sac, placenta, umbilical cord, fetal and adolescent skin, and blood. Bone marrow cells maybe obtained from iliac crest, femora, tibiae, spine, rib or other medullary spaces.

Methods for the selective destruction, ablation or removal of proliferating or rapidly dividing cells from a tissue or organ are well-known in the art, e.g., methods of cancer or tumor treatment For example, the perfused placenta may be irradiated with electromagnetic, UV, X-ray, gamma- or beta-radiation to eradicate all remaining viable, •18CA 02856986 2014-07-16 endogenous cells. The foreign cells to be propagated are introduced into the irradiated placental bioreactor, for example, by perfusion.

5.1 COLLECTION OF CELLS FROM THE PLACENTA

As disclosed above, after exsanguination and perfhsion of the placenta, embryoniclike stem cells migrate into the drained, empty microcirculation where, according to the methods of the invention, they are collected, preferably by collecting the effluent perfusate in a collecting vessel.

In preferred embodiments, cells cultured in the placenta are isolated from the effluent perfusate using techniques known by those skilled in the art, such as, for example, density gradient centrifugation, magnet cell separation, flow cytometry, or other cell separation or sorting methods well known in the art, and sorted, for example, according to the scheme shown in Figure 4.

In a specific embodiment, cells collected from the placenta are recovered from the effluent perfusate by centrifugation at 5000 x g for 15 minutes at room temperature, which separates cells from contaminating d&amp;ris and platelets. The cell pellets are resuspended in IMDM serum-free medium containing 2U/ml heparin and 2mM EDTA (GibcoBRL, NY). The total mononuclear cell fraction was isolated using Lymphoprep (Nycomed Pharma,

Oslo, Norway) according to the manufacturer's recommended procedure and the mononuclear cell fraction was resuspended. Cells were counted using a hemocytometer.

Viability was evaluated by trypan blue exclusion. Isolation of cells is achieved by “differential trypsinizalion,” using a solution of 0.05% trypsin with 0.2% EDTA (Sigma, St Louis MO). Differential trypsinization was possible because fibroblastoid colls detached from plastic surfaces within about five minutes whereas the other adherent populations required more than 20-30 minutes incubation. The detached fibroblastoid cells were

<img file="CA2856986C_D0015.tif" />

Solution (TNS, Bio Whittaker). The cells were washed in HDMEM and resuspended in MSCGM.

In another embodiment, the isolated placenta is perfused for a period of time without collecting the perfusate, such that the placenta may be perfused for 2,4,6,8,10,12,20 and 24 hours or even days before the perfusate is collected.

In another embodiment, cells cultured in the placenta bioreactor are isolated from the placenta by physically dissecting the cells away from the placenta.

In another embodiment, cells cultured in the placenta bioreactor are isolated from the placenta by dissociating the tissues of the placenta or a portion thereof and recovering

-19CA 02856986 2014-07-16 the cultured cells by art-known cell separation or sorting methods such as density gradient centrifugation; magnet cell separation, flow cytometry, etc.

In a preferred embodiment, perfusion of the placenta and collection of effluent perfusate is repeated once or twice during the culturing of the placenta, until the number of recovered nucleated cells falls below 100 cella/mL The perfusates are pooled and subjected to light centrifugation to remove platelets, debris and do-nucleated cell membranes. The nucleated cells are then isolated by Ficoll-Hypsque™ density gradient centrifugation and after washing, resuspended in HJDMEM. For isolation of the adherent cells, aliquots of 5-10 x 10® cells are placed in cadi of several T-75 flasks and cultured with commercially available Mesenchymal Stem Cell Growth Medium (MSCGM) obtained from BioWhittaker:, and placed in a tissue culture incubator (37“C, 5% COJ. After 10 to 15 days, non-adherent cells are removed from the flasks by washing with PBS. The PBS is then, replaced by MSCGM Flasks are preferably examined daily for the presence of various adherent cell types and in particular, for identification and expansion of dusters of fibroblastoid cells.

In other embodiments, the cells collected from the placenta arc ayopreserved fix use at a later time. Methods for cryopreservation of cells, such as stem cells, are well known in the art, for example, cryopreservation using the methods of Boyse et aL (ILS. Patent No. 5,192,553, issued March 9,1993) or Hu et el (WO 00/73421, published December 7, 2000).

53. CELL POPULATIONS OBTAINED FROM OR CULTURED IN

PLACENTA

Embryonic-like stem cells obtained in accordance with the methods of the invention may include pluripotent cells, Le., cells that have complete differentiation versatility, that are self-renewing, and can remain damant or quiescent within tissue. The stem cells which maybe obtained from the placenta include embryonic-like stem cells, multipotcnt cells, committed progenitor cells, and fibroblastoid cells.

The first collection of blood from the placenta is referred to as cord blood which contains predominantly CD34+ and CD38+ hematopoietic progenitor cells. fint twenty-four hours of post-partum perfusion, higfi concentrations of CD34+ and CD38 hemaiopoietic progenitor cells may be isolated from the placenta, along with high concentrations of CD3 4- and CD38+ hematopoietic progenitor cells. After about twentyfour hours of perfhsion, high concentrations of CD34- and CD38- cells can be isolated from the placenta along with the aforementioned cells. The isolated perfused placenta of ths invention provides a source of large quantities of stem cells enriched for CD34+ and CD38stem cells and CD34-and CD38+stern cells. Tlieisolaiedplacentawhiclihasbeen

-20CA 02856986 2014-07-16 perfused for twenty-four hours or more provides a source of large quantities of stem cells enriched for CD34- and CD38- stem cells.

In a preferred embodiment, embryonic-like stem cells obtained by the methods of the invention are viable, quiescent, pluripotent stem cells that exist within a foil-term human placenta and that can bo recovered following successful birth and placental expulsion, resulting in the recovery of as many as one billion nucleated cells, which yield 50-100 million multipotent and pluripotent stem cells.

The human placental stem cells provided by the placenta are surprisingly embryonic-like, for example, the presence of the following cell surface markers have been identified for these cells: SSEA3-, SSEA4-, OCT-4+ and ABC-p*. Preferably, foe embryonic-like stem cells of the invention are characterized by the presence of OCT-4+ and ABC-p+ cell surface markers. Thus, the invention encompasses stem cells which have not been isolated or otherwise obtained from an embryonic source but which can be identified by the following markers: SSAE3-, SSAE4-, OCT-4+and ABC-p4-. In one embodiment, the human placental stem cells do not express MHC Class 2 antigens.

The stem cells isolated from the placenta are homogenous, and sterile. Further, the stem cells are readily obtained in a form suitable for administration to humans, Le., they are of pharmaceutical grade.

<img file="CA2856986C_D0016.tif" />

be identified by the presence of the following cell surface markers: OCT-44- and ABC-pt Further, the invention encompasses embryonic stem cells having the following markers:

CD10+, CD38-, CD29+, CD34-, CD44+, CD45-, CD54+, CD90+, SH2+, SH3+, SH4+,

SSBA3-, SSBA4-, OCT-4+, and ABC-p+. Such cell surface markers arc routinely determined according to methods well known in the art, e.g. by flow cytometry, followed by washing and staining with an anti-cell surface marker antibody. For example, to determine tiie presence of CD-34 or CD-38, cells maybe washed in PBS and then double-stained with

<img file="CA2856986C_D0017.tif" />

Mountain View, CA).

In another embodiment, cells cultured in tho placenta bioreactor are identified and characterized by a colony forming unit assay, which is commonly known in the art, such as

Mesen Cult™ medium (stem cell Technologies, Inc., Vancouver British Columbia)

<img file="CA2856986C_D0018.tif" />

induced to differentiate along specific cell lineages, including adipogénie, chondrogenic, osteogenic, hematopoietic, myogenic, vasogenic, neurogenic, and hepatogenic. In certain embodiments, embryonic-like stem cells obtained according to the methods of the invention

-21CA 02856986 2014-07-16 aie induced to differentiate for use in transplantation and ex vivo treatment protocols. In certain embodiments, embryonic-like stem cells obtained by the methods of the invention are induced to differentiate into a particular cell type and genetically engineered to provide a therapeutic gene product hr a specific embodiment, embryonic-like stem cells obtained by the methods of the invention are incubated with a compound in vitro that induces it to differentiate, followed by direct transplantation of the differentiated ccllsto a subject Thus, the invention encompasses methods of differentiating the human placental stem cells using standard culturing media. Further, the invention encompasses hematopoietic cells, neuron cells, fibroblast cells, strand cells, mesenchymal cells and hepatic cells.

Embryonic-like stem cells may also be further cultured after collection from the placenta using methods well known in the art, for example, by culturing on feeder cells, such as irradiated fîbroblaste, obtained from the sama placenta as the embryonic-like stem cells ar from other human or nonhuman sources, or in conditioned media obtained from cultures of such feeder cells, in order to obtain continued long-term cultures of embryoniclike stem cells. The embryonic-like stem cells may also be expanded, either within the placenta before collection from the placental bioreactor or in vitro after recovery from the placenta. In certain embodiments, the embryonic-like stem cells to be expanded are exposed to, or cultured in the presence of an agent that suppresses cellular differentiation. Such agents are well-known in the art and include, but are not limited to, human Delta-1 and human Serrate-1 polypeptides (see, Sakano et ai, U.S. Patent No. 6337,387 entitled Differentiation-suppressive polypeptide”, issued January 8,2002), leukemia inhibitory factor (LIF) and stem cell factor. Methods for the expansion of cell populations are also known in the art (see e.g., Emerson et al., U.S. Patent No. 6326,198 entitled Methods and compositions for the ex vivo replication of stem cells, for the optimization of hematopoietic progenitor cell cultures, and for increasing the metabolism, GM-CSF secretion and/or IL-6 secretion of human stromal cells”, issued December 4,2001; Kraus et al., U.S. Patent No. 6,338,942, entitled Selective expansion of target cell populations”, issued January 15, 2002).

The embryonic-like stem cells may be assessed for viability, proliferation potential, and longevity using standard techniques known in the art, such as trypan blue exclusion assay, fluorescein diacetate uptake assay, propidium iodide uptake assay (to assess viability); and thymidine uptake assay, MIT cell proliferation assay (to assess proliferation). Longevity may be determined by methods well known in the art, such as by determining the maximum number of population doubling in an extended culture.

-22CA 02856986 2014-07-16

In certain embodiments, the differentiation of stem cells or progenitor cells that are cultivated in the exsanguinated, perfused and/or cultured placenta is modulated using an agent or pharmaceutical compositions comprising a dose and/or doses effective upon single or multiple administration, to exert an effect sufficient to inhibit, modulate and/or regulate the differentiation of a cell collected from the placenta.

Agents that can induce stem or progenitor cell differentiation are well known in the art and include, but are not limited to, Ca²*, EGF, aFGF, bFGF, PDGF, kératinocyte growth factor (KGF), TGF-β, cytokines (eg., IL-lo, IL-Ιβ, IFN-γ, TEN), retinoic acid, transfenin, hormones (eg., androgen, estrogen, insulin, prolactin, triiodothyronine, hydrocortisone, dexamethasone), sodium butyrate, TP A, DMSO, NMF, DMF, matrix elements (eg., collagen, laminin, heparan sulfete, Matrigel™), or combinations thereof

Agents that suppress cellular differentiation are also well-known in the art and include, but are not limited to, human Delta-1 and human Sarato-l polypeptides (ree, Sakano et dL, U.S. Patent No. 6,337,387 entitled 'Differentiation-suppressive polypeptide*’, issued January 8,2002), leukemia inhibitory factor (LIF), and stem cell factor.

The agent used to modulate differentiation can be introduced into the placental bioreactor to induce differentiation of the cells being cultured in the placenta. Alternatively,

<img file="CA2856986C_D0019.tif" />

or removed from the placenta.

Determination that a stem cell has differentiated into a particular cell type may be accomplished by methods well-known in the art, e.g., measuring changes in morphology and cell surface markers using techniques such as flow cytometry or immunocytochemistry (ag., staining cells with tissue-specific or cell-marker specific antibodies), by examination of the morphology of cells using light or confocal microscopy, or by measuring changes in gene expression using techniques well known in the art, such as PCR and gene-expression profiling.

In another embodiment, the cçslls cultured in the placenta are stimulated to produce bioactive molecules, such as immunoglobulins, hormones, enzymes.

hi another embodiment, the cells cultured in the placenta are stimulated to proliferate, for example, by administration of erythropoietin, cytokines, lymphokines, interfaons, colony stimulating factors (CSF’s), interferons, chemokines, interleukins, recombinant human hematopoietic growth factors including ligands, stem cell fedora, thrombopoeitin (Tpo), interleukins, and granulocyte colony-stimulating factor (G-CSF) or other growth fee tors.

-23CA 02856986 2014-07-16

III another embodiment, cells cultured'in the placenta are genetically engineered either prior to, or after collection from, the placenta, using, for example, a viral vector such as an adenoviral or retroviral vector, or by using mechanical means such as liposomal or chemical mediated uptake of the DNA.

A vector containing a transgene can be introduced into a cell of interest by methods well known in the art, e.g., transfection, transformation, transduction, electroporation, infection, microinjection, edi fusion, DEAB dextran, calcium phosphate precipitation, liposomes, LEPOFECTIN™, lysosome fusion, synthetic cationic lipids, use of a gene gun or aDNA vector transporter, such that the transgene is transmitted to daughter cells, e.g., the daughter embryonic-like stem cells or progenitor cells produced by the division of an embryonic-like stem cell. For various techniques for transformation or transfection of mammalian cells, see Keown et al, 1990, Methods EnzymoL 185:527-37; Sambrook et al,

2001, Molecular Cloning, A Laboratory Manual, Third Edition, Cold Spring Harbor

Laboratory Press, N.Y.

Preferably, the transgene is introduced using any technique, so long as it is not destructive to the cell’s nuclear membrane or other existing cellular or genetic structures. In certain embodiments, the transgene is inserted into the nucleic genetic material by microinjection. Microinjection of cells and cellular structures is commonly known and practiced in the art

For stable transfection of cultured mammalian cells, such as cells culture in a

<img file="CA2856986C_D0020.tif" />

The efficiency of integration depends upon the vector and transfection technique used. In order to identify and select integrants, a gene that encodes a selectable marker (&amp;£., for resistance to antibiotics) is generally introduced into the host embryonic-like stem cell along with tiw gene sequence of interest Preferred selectable markers include those that confer resistance to drugs, such as G418, hygromycin and methotrexate. Cells stably transfected with the introduced nucleic acid can be identified by drag selection (e.g., cells that have incorporated the selectable marker gene will survive, while the other cells die). Such methods are particularly useful in methods involving homologous recombination in mammalian cells (eg., in embryonic-like stem cells) prior to introduction or transplantation

I of the recombinant cells into a subject or patient

A number of selection systems may be used to select transformed host emhiyonicIike cells. In particular, the vector may contain certain detectable or selectable markers. Other methods of selection include but are not limited to selecting for another marker such as: the herpes simplex virus thymidine kinase (Wigler et aL, 1977, Cell 11:223),

-24CA 02856986 2014-07-16 hypoxanthine-guanine phosphoribosyltransftrase (Szybalska and Szybalski, 1$62, Proc. Natl. Acad. Sci. USA 48:2026), and adenine phosphoribosyltransferase (Lowy et al., 1980, Cell 22:817) genes can be employed in tk-, hgprt- or aprt- cells, respectively. Also, antimetabolite resistance can be used as the basis of selection for the following genes: dhfr, which confers resistance to methotrexate (Wigler et al., 1980, Proc. Natl. Acad. Sci. USA 77:3567; O’Hare et al., 1981, Proc. Natl. Acad. Sd. USA 78:1527); gpt, which confias resistance to mycophenolic acid (Mulligan and Berg, 1981, Proc. Natl. Acad. Sci. USA 78: 2072); neo, which confers resistance to the aminoglycoside G-418 (Colberre-Garapin et al., 1981, J. Mol. Biol. 150:1); and hygro, which confers resistance to hygromycin (Santerre et al, 1984, Gene 30:147).

The transgene may integrate into the genome of the cell of interest, preferably by random integration, In other embodiments the transgene may integrate by a directed method, eg., by directed homologous recombination (i.e., “knock-in” or ‘‘knock-out** of a gene of interest in the genome of cell of interest), Chappel, U.S. Patent No. 5,272,071; and

PCT publication No. WO 91/06667, published May 16,1991; U.S. Patent 5,464,764; Capecchi et al, issued November 7,1995; U.S. Patent 5,627,059, Capecchi el al issued, May 6,1997; U.S. Patent 5,487,992, Capecchi et al., issued January 30,1996).

Methods for generating cells having targeted gene modifications through homologous recombination are known in the art The construct will comprise at least a portion of a gene of interest with a desired genetic modification, and will include regions of homology to the target locus, Le., the endogenous copy of the targeted gene in the host’s genome. DNA constructs for random integration, in contrast to those used for homologous recombination, need not include regions of homology to mediate recombination. Markers can be included in the targeting construct or random construct for performing positive and negative selection for insertion of the transgene.

To create a homologous recombinant cell, e.g., a homologous recombinant embryonic-like stem cell, endogenous placental cell or exogenous cell cultured in the placenta, a homologous recombination vector is prepared in which a gene of interest is flanked at its 5' and 3' ends by gene sequences that are endogenous to the genome of the targeted cell, to allow for homologous recombination to occur between the gene of interest cairiedby the vector and the endogenous gene in the genome of the targeted cell. The additional flanking nucleic add sequences are of sufficient length for successful homologous recombination with the endogenous gene in the genome of die targeted cell.

Typically, several kilobases of flanking DNA (both at the 5' and 3* ends) are included in the vector. Methods for constructing homologous recombination vectors and homologous

-25CA 02856986 2014-07-16 recombinant animals from recombinant stemcells are commonly known in the art (see, e.g.,

Thomas and Capecchi, 1987, Cell 51:503; Bradley, 1991, Cun'. Ορια Bio/Technol. 2:82329; and PCT Publication Nos. WO 90/11354, WO 91/01140, and WO 93/04169.

In one embodiment, the genome of an exogenous cell cultured in the placenta according to the methods of the invention is a target of gene targeting via homologous recombination or via random integration.

In a specific embodiment, the methods of Bonadio et al. (U.S. Patent No. 5,942,496, entitled Methods and compositions for multiple gene transfer into bone cells, issued August 24,1999; and PCT WO95/Û611, entitled Methods and compositions for stimulating bone cells, published August 24,1995 ) are used to introduce nucleic acids into a cell of interest, such as a stem cell, progenitor cell or exogenous cell cultured in the placenta, eg., bone progenitor cells.

A USES OF CULTURED PLACENTA AS A BIOREACTOR

Exsanguinated and/or cultured placental cells can be used as a bioreactor for the cultivation of cells, tissues, and organs. The placental mesoderm provides an ideal stromal environment, including an abundance of small molecules and growth factors, lipopolysaccharides, and extracellular matrix proteins, necessary for organogenesis and tissue neogenesis.

In one embodiment, the invention provides a method of utilizing the isolated perfused placenta as a bioreactor for the propagation of exogenous cells. In accordance with this embodiment, the invention relates to an isolated placenta which contains a cell not derived from the placenta, wherein the engraftmeni of said cell into the placenta may stimulate the placenta to produce embryonic-like stem cells, or wherein the engrafted cell produces signals, such as cytokines and growth factors, which may stimulate the placenta to produce stem cells. The placenta may be engrafted with cells not placental in origin obtained from the parants, siblings or other blood relatives of the infant associated with the placenta. In another embodiment, the isolated placenta maybe engrafted with cells not placental in origin obtained from an individual whom is not the infant, nor related to tbe infant Likewise, the cells, tissues, organoids and organs, which are propagated and cultivated in the placenta may be transplanted into the infant associated with tbe placenta, the parents, siblings or other blood relatives of said infant ar into an individual not related to the infont.

In one embodiment of the invention, the placenta can be populated with any particular cell type and. used as a bioreactor for ex vivo cultivation of cells, tissues or organs.

-26CA 02856986 2014-07-16

Such cells, tissue or organ cultures may be harvested used in transplantation and ex vivo treatment pmtocols.In this embodiment, the placenta is processed to remove all endogenous cells and to allow foreign (Le, exogenous) cells to be introduced and propagated in the environment of the perfused placenta. Methods for removal of the endogenous cells are well-known in the art For example, foe perfiised placenta is irradiated with electromagnetic, UV, X-ray, gamma- or beta-radiation to eradicate all remaining viable, endogenous cells. In one embodiment sub-lethal exposure to radiations eg., 500 to 1500 CGy can be used to preserve the placenta but eradicate undesired cells. For international on lethal v. non-lefoal ionizing radiation (see Chapter 5 “Biophysical and Biological Effects of

Ionizing Radiation” from foe United States Department of Defense The foreign cells of interest to be propagated in foe irradiated placental bioreactor are then introduced, for example, by vascular perfusion or direct intra-parenchymal injection.

In another embodiment, foe biareactor may be used to produce and propagate novel chimeric cells, tissues, or organs. Such chimeras may be created using placental cells and one or more additional cell types as starting materials in a bioreactor. The interaction, or “cross-talk” between foe different cell types can induce expression patterns distinct from either of foe starting cell types. In one embodiment, for example, an autologous chimera is generated by propagating a patient’s autologous placental cells in a bioreactor with another cell type derived from the same patient, bi another embodimenti for example, a heterologous chimera may be generated by addition of a patient's cells, Le, blood cells, to a bioreactor having heterologous placental.cells. In yet another embodiment, the placental cells may be derived from a patient, and a second cell type from a second patient. Chimeric cells are then recovered having a different phenotypic and/or genetic characteristics from either of foe starting cells. In a specific embodiment, the heterologous cells are of the same haplotype, and the chimeric cells are reintroduced into the patient

In other embodiments, the bioreactor may be used for enhanced growth of a particular cell type, whether native or synthetic in origin, or for foe production of a cell-type specific product For example, in. one embodiment, foe placental biareactor may be used to stimulate pancreatic islet cells to produce insulin. The bioreactor is particularly >

can be dependent upon proper post-translational modification. Thus, the bioreactor is useful for foe production of therapeutic proteins, growth factors, cytokines, and other natural ar recombinant therapeutic molecules, such as but not limited to, erythropoietin, interleukins, and interferons.

<img file="CA2856986C_D0021.tif" />

<img file="CA2856986C_D0022.tif" />

-27CA 02856986 2014-07-16

<img file="CA2856986C_D0023.tif" />

engineered cells to provide a therapeutic gene product, and employed for large-scale production of the recombinant product In one embodiment, for example, the reactor may be used to enhance antibody production. The placenta may be populated with antibody5 producing cells, such as hybridomas, which produce a specific monoclonal antibodies, which are homogeneous populations of antibodies to a particular antigen.· Hybridomas may be obtained by any technique, including, but not limited to, the hybridoma technique of Kohler and Milstem (1975, Nature 256,495-497; and U.S. Patent No. 4376,110), the human B-cell hybridoma technique (Kosbor et al, 1983, Immunology Today 4,72; Cole et 10 ai, 1983, Proc. NatL Acad. Set USA 80,2026-2030), and the EBV-hybridoma technique (Cole et aL, 1985, Monoclonal Antibodies And Cancer Therapy, Alan R. Liss, Inc., pp. 7796). The mAb-producing hybridomas may be cultivated in the bioreactor to produce high titers of mAbs.

Alternatively, where an antigen is unknown, the bioreactor maybe used to generate 15 antibodies specific for a particular coll-type, which may then be used identify the unknown antigen. For example, antibodies may be generated against an unknown tumor-specific antigen in a cancer patient by culturing a whole blood specimen from a cancer patient, expanding the cells in a bioreactor, and then screened for antibodies that specifically react against a patient’s tumor cells.

In another embodiment, the bioreactor may be used to produce viruses in culture and for screening for antiviral agents in culture. This method is of particular interest for those viruses, such as parvovirus and human immunodeficiency virus, which are difficult to propagate in cell culture conditions.

The bioreactor may also be used as a support for screening for therapeutic molecules 25 which modulate the activity of a particular cell type, such as the activity or expression of a gene product of interest or the activation of a signal transduction pathway, Jri this embodiment, a cell type of interest may be cultured and expanded in the biorcactor. The cell may be naturally occurring cell, or a cell engineered to express a recombinant gene product The bioreactor is then be contacted with candidate therapeutic molecules, such as 30 small molecules, nonpeptides, antibodies, etc., or libraries of such candidate therapeutic molecules. The cells are then analyzed for a change in a desired activity in the presence or absence of the candidate therapeutic molecule. For example, such desired activity might be an increase or decrease in growth rate, and change in gene expression, or a change in binding or uptake of the candidate therapeutic molecule.

-28CA 02856986 2014-07-16

Several types of methods are likely Wbe particularly convenient and/or. useful for screening test agents. These include, but are not limited to, methods which measure binding of a compound, methods which measure a change in the ability cells to interact with an antibody or ligand, and methods which measure the activity or expression of reporter* protein, that is, an enzyme or other detectable or selectable protein, which has been placefl under the control of a control region of interest Thus, in a preferred embodiment, both naturally occurring and/or synthetic compounds (e.g., libraries of small molecules or peptides), may be screened for therapeutic activity. The screening assays can be used to

<img file="CA2856986C_D0024.tif" />

molecules that modulate a cell-type specific activity. Recombinant, synthetic, and otherwise exogenous compounds may have hmding capacity and, therefore, maybe candidates for pharmaceutical agents. Alternatively, the proteins and compounds include endogenous cellular components which interact with the identified genes and proteins jg vivo. Such endogenous components may provide new targets for pharmaceutical and therapeutic interventions.

In another embodiment of foe invention, the placenta is used as a bioreactor for propagating endogenous celle (i&amp;, cells that originate from the placenta), including but not limited to, various kinds of pluripotent and/or totipotent embryonic-like stem cells and lymphocytes, hi one embodiment, the placenta is incubated for varying periods of time with perfusate solution as disclosed herein. Such endogenous cells of placental origin wy be transformed to recombinantly express a gene of interest, to express mutations, and/or any be engineered to delete a genetic locus, using “knock out” technology. For example, an endogenous target gene maybe deleted by inactivating or knocking out foe target gene or its promoter using targeted homologous recombination (e.g, see Smithies, et aL, 1985, Nature 317,230-234; Thomas &amp; Capecchi, 1987, Cell 51,503-512; Thompson, et al, 1989, Cell 5,313-321). For example, a mutant, Don-functional target gene (or a completely unrelated DNA sequence) flanked by DNA homologous to foe endogenous target gene (either the coding regions or regulatory regions cf the target gene) can be used, with or without a selectable marker and/or a negative selectable marker, to transfect cells that express the target gene in vivo. Insertion of the DNA construct, via targeted homologous recombination, results in inactivation of the target gene. Such approaches maybe used to remove, replace, ar alter gene expression of interest in cells, tissue, and/or organs. Thia approach may bo used to. alter the phenotype of a cell, tissue, or organ, which may then be introduced into a human subject

-29CA 02856986 2014-07-16

In other embodiments, a placenta cell may be induced to differentiate into a particular cell type, either ex vivo or in vivo. For example, pluripotent embiyonic-like stem cells maybe injected into a damaged organ, and for organ neogenesis and repair of injury in vivo. Such injury may be due to such conditions and disorders including, but not limited to, myocardial infarctinn, seizure disorder, multiple sclerosis, stroke, hypotension, cardiac arrest, ischemia, inflammation, age-related loss of cognitive fonction, radiation damage, cerebral palsy, neurodegenerative disease, Alzheimer’s disease, Parkinson’s disease, Leigh disease, AIDS dementia, memory loss, amyotrophic lateral sclerosis, ischemic renal disease, brain or spinal cord trauma, heart-lung bypass, glaucoma, retinal ischemia, or retinal trauma.

The embryonic-like stem cells isolated from the placenta may be used, in specific embodiments, in autologous or heterologous enzyme replacement therapy to treat specific diseases or conditions, including, but not limited to lysosomal storage diseases, such as TaySachs, Niemann-Pick, Fabry’s, Gaudier’s, Hunter’s, and Hurler’s syndromes, as well as other gangliosidoses, mucopolysaccharidoses, and glycogenoses.

hi other embodiments, the cells may be used as autologous or heterologous transgene carriers in gene therapy to correct inborn errors of metabolism, adrcnolcukodystrophy, cystic fibrosis, glycogen storage disease, hypothyroidism, sickle cell anemia, Pearson syndrome, Pompe’s disease, phenylketonuria (PKU), porphyrias, maple syrup urine disease, homocystinuria, mucoplysaccharide nosis, chronic granulomatous disease and tyrosinemia and Tay-Sachs disease or to treat cancer, tumors or other

<img file="CA2856986C_D0025.tif" />

hi other embodiments, tho cells may be used in autologous or heterologous tissue regeneration or replacement therapies or protocols, including, but not limited to treatment of corneal epithelial defects, cartilage repair, facial dermabrasion, mucosal membranes, tympanic membranes, intestinal linings, neurological structures (e.g., retina, auditory neurons in basilar membrane, olfactory neurons in olfactory epithelium), bum and wound repair for traumatic injuries of the skin, or for reconstruction of other damaged or diseased organs or tissues.

<img file="CA2856986C_D0026.tif" />

methods of the invention would, in certain embodiments, reduce the need for large bone marrow donations. Approximately 1 x 10^s to 2 x 10* bone marrow mononuclear cells per kilogram of patient weight must be infused for engraftment in a bone marrow transplantation (Le., about 70 ml of marrow for a 70 kg donor). To obtain 70 ml requires an intensive donation and significant loss.of blood in the donation process. In. a specific

-30CA 02856986 2014-07-16 embodiment, cells from a small bone marrow’donation (eg., 7-10 ml) could beexpanded by propagation in a placental bioreactoi before infusion into a recipient.

<img file="CA2856986C_D0027.tif" />

the blood stream. In another embodiment, such exogenous stem cells or exogenous progenitor cells are collected by pheresis, a procedure in which blood is withdrawn, one or more components are selectively removed, and the remainder of the blood is reinfused into the donor. The exogenous cells recovered by pheresis are expanded by propagation in a placental bioreactor, thus eliminating the need for bone marrow donation entirely.

hi another embodiment, expansion of exogenous Cells in a placental bioreactor is used as a supplemental treatment in addition to chemotherapy. Most chemotherapy agents used to target and destroy cancer cells act by killing all proliferating cells, i.e, cells going through cell division. Since bone marrow is one of the most actively proliferating tissues in the body, hematopoietic stem cells are frequently damaged or destroyed by chemotherapy agents and in consequence, blood cell production is diminishes or ceases. Chemotherapy must be terminated at intervals to allow the patient’s hematopoietic system to replenish, the blood cell supply before resuming chemotherapy. It may take a month or more for the formerly quiescent stem cells to proliferate and increase the white blood cell count to acceptable levels so that chemotherapy may resume (when again, the bone marrow stem cells arc destroyed).

While the blood cells regenerate between chemotherapy treatments, however, the cancer has time to grow and possibly become more resistant to the chemotherapy drugs due to natural selection. Therefore, the longer chemotherapy is given and the shorter the duration between treatments, the greater the odds of successfully killing the cancer. To shorten the time between chemotherapy treatments, embryonic-like stem cells or progenitor cells collected according to the methods of the invention could be introduced into the patient Such treatment would reduce the time the patient would exhibit a low blood cell count and would therefore pennit earlier resumption of the chemotherapy treatment

The embryonic-like stem cells, progenitor cells, foreign cells, ar engineered cells obtained from a placenta according to the methods of the invention can be used in the manufacture of a tissue or organ in vivo. The methods of the invention encompass using cells obtained from the placenta, eg., embiyomc-likc stem cells, progenitor cells, ar foreign stem or progenitor cells, to seed a matrix and to be cultured under the appropriate conditions to allow the cells to differentiate and populate the matrix. The tissues and organs obtained by tile methods of the invention may be used for a variety of purposes, including research and therapeutic purposes.

-31CA 02856986 2014-07-16

5.5 USES OF EMBRYONIC-LIKE STEM CELLS

The embryonic-like stem cells of the invention can be used for a wide variety of therapeutic protocols in which a tissue or organ of the body is augmented, repaired or replaced by the engraflment, transplantation or infusion of a desired cell population, such as a stem cell or progenitor cell population. The embryonic-like stem cells of the invention can be used to replace or augment existing tissues, to introduce new or altered tissues, or to join together biological tissues or structures. The embryonic-like stem cells of the invention can also be substituted for embryonic stem cells in therapeutic protocols in which embryonic stem cells would be typically be used.'

In a preferred embodiment of the invention, cmbryonic-like stem cells and other stem cells from the placenta may be used as autologous and allogenic, including matched and mismatched ELA type hematopoietic transplants, hi accordance with the use of embryonic-like stem cells as allogenic hematopoietic transplants it may be necessary to treat the host to reduce immunological rejection of the donor cells, such as those described in U.S. Patent No. 5,800,539, issued September 1,1998; and U.S. Patent Na 5,806^29, issued September 15, 1998.

Far example, embryonic-like stem cells of the invention can be used in therapeutic transplantation protocols, e.g., to augment or replace stem or progenitor cells of die liver, pancreas, kidney, lung, nervous system, muscular system, bone, bone marrow, thymus, spleen, mucosal tissue, gonads, ar hair.

<img file="CA2856986C_D0028.tif" />

(e.g., chondrocytes, hepatocytes, hematopoietic cells, pancreatic parenchymal cells, neuroblasts, muscle progenitor cells, eta) in therapeutic or research protocols in which progenitor cells would typically be used.

Embryonic-like stem cells of the invention can be used for augmentation, repair or replacement of cartilage, tendon, or ligaments. For example, in certain embodiments,

<img file="CA2856986C_D0029.tif" />

grown from embryonic-like stem calls of the invention In other embodiments, joints (&lt;g, knee) are reconstructed with cartilage tissue constructs grown from embryooic-Hke stem cells. Cartilage tissue constructs can also be employed in major reconstructive surgery for different types of joints (for protocols, see e.g._t Resnick, D., and Niwayama, G., eds., 1988, Diagnosis of Bone and Joint Disorders, 2d ed., W. B. Saunders Co.).

The embryonic-like stem cells of the invention can be used to repair damage of tissues and organs resulting from disease. In such an embodiment, a patient can be administered embryonic-like stem cells to regenerate or restore tissues or organs which have

-32CA 02856986 2014-07-16 been damaged as a consequence of disease, e.g., enhance immune system following chemotherapy or radiation, repair heart tissue following myocardial infarction.

The embryonic-like stem cells of the invention can be used to augment or replace bone marrow cells in bone marrow transplantation. Human autologous and allogenic bone marrow transplantation are currently used as therapies for diseases such as leukemia, lymphoma and other life-threatening disorders. The drawback of these procedures, however, is that a large amount of donor bone marrow must be removed to insure that there is enough cells for engraftment.

The embryonic-like stem cells collected according to die methods of the invention can provide stem cells and progenitor cells that would reduce the need for large bone marrow donation. It would also be, according to the methods of the invention, to obtain a small marrow donation and then expand the number of stem cells and progenitor cells culturing and expanding in the placenta before infusion or transplantation into a recipient The embryonic-like stem cells isolated from the placenta may be used, in specific embodiments, in autologous or heterologous enzyme replacement therapy to treat specific diseases or conditions, including, but not limited to lysosomal storage diseases, such as TaySachs, Niemann-Pick, Fabry’s, Gaucher’s, Hunter’s, Hurler’s syndromes, aa well as other gangliosidoses, mucopolysaccharidoses, and glycogenoses.

hi other embodiments, the cells may be used as autologous or heterologous transgene carriers in gone therapy to correct inborn errors of metabolism such as adrenoleukodystrophy, cystic fibrosis, glycogen storage disease, hypothyroidism, sickle cell anemia, Pearson syndrome, Pompe's disease, phenylketonuria (PKU), and Tay-Sachs disease, porphyrias, maple syrup urine disease, homocystinuria, mucqpolypsaocharide nosis, chronic granulomatous disease, and tyrosinemia. or to treat caitoer, tumors or other pathological conditions.

<img file="CA2856986C_D0030.tif" />

regeneration or replacement therapies or protocols, including, but not limited to treatment of comeal epithelial defects, cartilage repair, facial dermabrasion, mucosal membranes, tympanic membranes, intestinal lining», neurological structures retina, auditory neurons in basilar membrane, olfactory neurons in olfactory epithelium), bum and wound repair for traumatic injuries of the skin, scalp (hair) transplantation, or for reconstruction of

<img file="CA2856986C_D0031.tif" />

<img file="CA2856986C_D0032.tif" />

methods of the invention would, in certain embodiments, reduce the need for large bone marrow donations. Approximately 1 x 10* to 2 x 10* bone marrow mononuclear cells per • 33CA 02856986 2014-07-16 kilogram of patient weight must be infused fdi engraftment in a bone marrow transplantation (ie, about 70 ml of marrow for a 70 kg donor). To obtain 70 ml requires an t intensive donation and significant loss of blood in the donation process. In a specific embodiment, cells from a small bone marrow donation (e.g., 7-10 ml) could be expanded by propagation in a placental bioreactor before infusion into a recipient hi another embodiment, the embryonic-like stem cells can be used in a supplemental treatment in addition to chemotherapy. Most chemotherapy agents used to target and destroy cancer cells act by killing all proliferating cells, i.e., cells going through cell division. Since bone marrow is one of the most actively proliferating tissues in the body, hematopoietic stem cells are frequently damaged or destroyed by chemotherapy agents and in consequence, blood cell production is diminishes or ceases. Chemotherapy must be terminated at intervals to allow the patient's hematopoietic system to replenish the blood cell supply before resuming chemotherapy. It may take a month or more for the formerly quiescent stem cells to proliferate and increase the white blood cell count to acceptable levels so that chemotherapy may resume (when again, the bone marrow stem cells are destroyed).

While the blood cells regenerate between chemotherapy treatments, however, the cancer has time to grow and possibly become more resistant to the chemotherapy drugs due to natural selection. Therefore, the longer chemotherapy is given and the shorter the duration between treatments, the greater the odds of successfully killing the cancer. To

<img file="CA2856986C_D0033.tif" />

cells collected according to the methods of the invention could be introduced into the patient Such treatment would reduce the time the patient would exhibit a low blood cell count, and would therefore permit earlier resumption of the chemotherapy treatment In another βπύχχίπηβηζ the human placental stem cells can be used to treat or prevent genetic diseases such as chronic granulomatous disease.

5.6 PHARMACEUTICAL COMPOSITIONS

The present invention encompasses pharmaceutical compositions comprising a dose and/or doses effective upon single or multiple administration, prior to or following transplantation of conditioned or unconditioned human progenitor stem cells, exerting effect sufficient to inhibit, modulate and/or regulate the differentiation of human pluripotent and multipotent progenitor stem cells of placental origin into mesodermal and/or hematopoietic lineage cells.

-34CA 02856986 2014-07-16

In accordance with fois embodimenf^the embryonic-like stem cells of the invention may be formulated as an injectable (&amp;g-, PCT WO 96/39101).

In an alternative embodimenf the cells and tissues of foe present invention, may be formulated using polymerizable or cross linking hydrogels as described in

U.S. Patent Nos. 5,709,854; 5,516^32; 5,654, 381.

6. EXAMPLE

6.1. EXAMPLE 1: ANALYSIS OF CELL TYPES RECOVERED FROM PERFUSATE OF DRAINED PLACENTA

This example describes foe analysis of foe cell types recovered from the effluent

<img file="CA2856986C_D0034.tif" />

Twenty ml of phosphate buffered saline solation (PBS) was added to the perfusion liquid and a 10 ml portion was collected and centrifuged for 25 minutes at 3000 rpm (revolutions per minute). The effluent was divided into four tubes and placed in an ice bath.

2.5 ml of a 1% fetal calf serum (FCS) solution in PBS was added and the tubes were centrifuged (140 minutes x 10 g (acceleration due to gravity)). The pellet was resuspended in 5 ml of 1% FCS and two tubes were combined. The total mononucleocytos were calculated by adding foe total lymphocytes and the total monocytes, and then multiplying foe result by the total cell suspension volume.

The following table discloses the types of cells obtained by perfusion of a cultured placenta according to foe methods described hereinabove.

WBC Lvm% MID% 100Q/ml

GRA%

Total #of

Volume Cells

<td> CB (Cord Blood)</td><td> 10.5</td><td> 432</td><td> 8</td><td> 48.8</td><td> 60 ml</td><td> 63X10*</td>

<td> PP (Placenta perfusate, room temperature)</td><td> 12.0</td><td> 62.9</td><td> 18.2</td><td> 18.9</td><td> 15 ml</td><td> 1.8X10*</td>

<td> PP, (Placenta perfusate, 37· Ç)</td><td> 11.7</td><td> 56.0</td><td> 19.2</td><td> 24.8</td><td> 30 ml</td><td> 33X10*</td>

-35CA 02856986 2014-07-16

Samples of PP were after Ficoll.

Total cell number of PP after Ficoll was 5.3 X 10^s and number of CB before processing is 6.3 X10*. Lym% indicates percent of lymphocytes; MID% indicates percent of midrange white blood cells; and GRA% indicates percent of granulocytes.

6.2. EXAMPLE 2: ANALYSIS OF CELLS OBTAINED BY PERFUSION . AND INCUBATION OF PLACENTA

The following example describes an analysis of cells obtained by perfusion and incubation of placenta according to the methods of the invention.

6.2.1. MATERIALS AND METHODS

Placenta donors were recruited from expectant mothers that enrolled in private umbilical cord blood harking programs and provided informed consent permitting the use of tire exsanguinated placenta following recovery of cord blood for research purposes. Donor data may be confidential· These donors also permitted usee inded data generated from the normal processing of their umbilical cord blood specimens for cryopreservation. This allowed comparison between the composition of the collected cord blood and the effluent perfusate recovered using the experimental method described below.

Following exsanguination of cord blood from the umbilical cord and placenta is stored at room temperature and delivered to the laboratory within four to twenty-four hour, according to the methods described hereinabove, the placenta was placed in a sterile, insulated container at room temperature and delivered to the laboratory within 4 hours of birth. Placentas were discarded ifj on inspection, they had evidence of physical damage such as fragmentation of the organ or avulsion of umbilical vessels. Placentas were maintained at room temperature (23±2°C) or refrigerated (4°C) in sterile containers for 2 to 20 hours. Periodically, the placentas were immersed and washed in sterile saline at 25±3°C to remove any visible surface blood or debris.

The umbilical cord was transected approximately 5 cm from its insertion into the placenta and the umbilical vessels were cannulated with TEFLON® or polypropylene catheters connected to a sterile fluid path allowing bi-directional perfusion of the placenta

<img file="CA2856986C_D0035.tif" />

ambient atmospheric conditions as well as real-time monitoring of intravascular pressure and flow rates, core and perfusate temperatures and recovered effluent volumes. A rango of conditioning protocols Were evaluated over a 24-hour postpartum period, and the cellular composition of the effluent fluid was analyzed by flow cytometry, light microscopy and colony forming unit assays.

-36CA 02856986 2014-07-16

6.2.2. PLACENTAL CONDITIONING

The donor placentas were processed at room temperature within 12 to 24 hours after delivery. Before processing, the membranes woe removed and the maternal site washed clean of residual blood. The umbilical vessels were cannulated with catheters made from 20 gauge Butterfly needles use for blood sample collection.

The donor placentas were maintained under varying conditions such as maintenance at 5-37’ 5% CO₂, pH 7.2 to 7.5, preferably pH 7.45, in an attempt to simulate and sustain a physiologically compatible environment for the proliferation and recruitment of residual embryonic-like stem cells. The cannula was flushed with IMDM serum-free medium (GibcoBRL, NY) containing 2U/ml heparin (Elkins-Sinn, NJ). Perfusion of the placenta continued at a rate of 50 ml per minute until approximately 150 ml of perfusate was collected. This volume of perfusate was labeled “early fraction.” Continued perfusion of the placenta at the same rate resulted in the collection of a second fraction of approximately 150 ml and was labeled, “late fraction.'* During the course of the procedure, the placenta was gently massaged to aid in the perfusion process and assist in the recovery of cellular material. Effluent fluid was collected from the perfusion circuit by both gravity drainage and aspiration through the arterial cannula.

Placentas were then perfused with heparinized (2U/ml) Dulbecco’s modified Eagle Medium (HJDMEM) at the rate of 15 ml/minute for 10 minutes and the perfusates were collected from the maternal sites within one hour and the nucleated cells counted. The perfusion and collection procedures were repeated once or twice until die number of recovered nucleated cells foil below 100/ml. The perfusates were pooled and subjected to light centrifugation to remove platelets, debris and de-nucleated cell membranes. The nucleated cells were then isolated by Ficoll-Hypaque density gradient centrifugation and after washing, resuspended in H.DMEM. For isolation of the adherent cells, aliquots of 5* 10 x 10^s cells were placed in each of several T-75 flasks and cultured with commercially available Mesenchymal Stem Cell Growth Medium (MSCGM) obtained from Bio Whittaker, and placed in a tissue culture incubator (37 °C, 5% CO]). After 10 to 15 days, tire non-adhérent cells were removed by washing with PBS, which was then replaced by MSCGM. The flasks were examined daily for tire presence of various adherent cell types and in particular, for identification and expansion of clusters of fibroblastoid cells.

6-2.3. CELL RECOVERY AND ISOLATION

Cells were recovered from foe perfusates by centrifugation at 5000 x g for 15 minutes at room temperature. This procedure served to separate cells from Amfominating

-37CA 02856986 2014-07-16 debris and platelets. The cell pellets were resuspended in IMDM serum-free médium containing 2UAnl heparin and 2mM EDTA (GibcoBRL, NY). The total mononuclear cell fraction was isolated using Lymphoprep (Nycomed Pharma, Oslo, Norway) according to the

<img file="CA2856986C_D0036.tif" />

resuspended. Cells were counted using a hemocytometer. Viability was evaluated by trypan blue exclusion. Isolation of mesenchymal cells was achieved by “differential trypsinization, using a solution of 0.05% trypsin with 02% EDTA (Sigma, St Louis MO). Differential trypsinization was possible because fibroblastoid cells detached from plastic surfaces within about five minutes whereas the other adherent populations required more than 20-30 minutes incubation. The detached fibroblastoid cells were harvested following trypsinization and trypsin neutralization, using Trypsin Neutralizing Solution (TNS, Bio Whittaker). The cells were washed in HJDMEM and resuspended in MSCGM.

Flow cytometry was carried out using a Becton-Dickinson FACSCalibur instrument and FTTC and PE labeled monoclonal antibodies (mAbs), selected on the basis of known markers for bone marrow-derived MSC (mesenchymal stem cells), were purchased from

BD. and Caltag laboratories (South San Francisco, CA.), and SH2, SH3 and SH4 antibody producing hybridomes were obtained from and reactivities of the mAbs in their cultured supernatants were detected by FTTC or PE labeled F(ab)*2 goat anti-mouse antibodies. Lineage differentiation was carried out using commercially available induction and maintenance culture media (BioWhittaker), used as per manufacturer's instructions.

6.2.4. ISOLATION OF PLACENTAL EMBRYONIC-LIKE STEM CELLS

Microscopic examination of the adherent cells in the culture flasks revealed morphologically different cell types. Spindle-shaped cells, round cells with large nuclei and numerous perinuclear small vacuoles, and star-shaped cells with several projections (through one of which star-shaped cells were attached to foe flask) were observed adhering to foe culture flasks. Although no attempts were made to further characterize these adherent cells, similar colls were observed in foe culture of bone marrow, cord and peripheral blood, and therefore considered to be non-stem cell-like in nature. The fibroblastoid cells, appearing last as clusters, were candidates for being MSC (mesenchymal stem cells) and were isolated by differential trypsinization and subcultured in secondary flasks. Phase microscopy of the rounded cells, after trypsinization, revealed that the colls were highly granulated; indistinguishable from foe bond marrow-derived MSC produced in the laboratory or purchased from Bio Whittaker. When subculturcd, the placenta-derived embryonic-like stem cells, in contrast to their earlier phase, adhered within hours, assumed

-38CA 02856986 2014-07-16 characteristic fibroblastoid shape, and formed a growth pattern identical to thé reference bone marrow-derived MSC. During subculturing and refeeding, moreover, the loosely bound mononuclear cells were washed out and the cultures remained homogeneous and devoid of any visible non-fibroblastoid cell contaminants.

6.25. RESULTS

The expression of CD-34, CD-38, and other stem cell-associated surface markers on early and late fraction purified mononuclear cells was assessed by flow cytometry. Recovered, sorted cells were washed in PBS and then double-stained with antiCD34 phycoerythrin and anri-CD38 fluorescein isothiocyanate (Becton Dickinson, Mountain View.CA).

Cell isolation was achieved by using magnetic cell separation, such as for example, Auto Macs (Miltenyi). Preferably, CD 34+ cell isolation is performed first

6.3 EXAMPLE 3: PERFUSION MEDIUM

The following example provides a formula of die preferred perfusate solution for the cultivation of isolated placentas

<td> Chemical</td><td> Source</td><td> Stock Concentration</td><td> Final Concentration</td><td> 500 ml</td>

<td> DMEM-LG</td><td> GibcoBRL11885084</td><td></td><td></td><td> 300 ml</td>

<td> MCDB201</td><td> Sigma M-6770</td><td> dissolved in H2O</td><td> pH to 7.2. filter</td><td> 200 ml</td>

<td> FCS</td><td> Hyclone</td><td> 100%</td><td> 2%</td><td> 10ml</td>

<td> rrs</td><td> Sigma 1*3146 or GibcoBRL41400045</td><td> lOOx</td><td> lx</td><td> 5ml</td>

<td> Pm&amp;Strcp</td><td> GibcoBRL15140- 122</td><td> lOOx</td><td> lx</td><td> 5 ml</td>

<td> LA.+BSA</td><td> Sigma+GibcoBRL BSA</td><td> 100x(l pg/ml of LA</td><td> lOng/mlofLA</td><td> 5ml</td>

<td> Dexamethasone</td><td> Sigma D-2915</td><td> 025mMinH2O</td><td> 0.05 pM</td><td> 100 pl</td>

<img file="CA2856986C_D0037.tif" />

CA 02856986 2014-07-16

<td> L-Ascorbic Acid</td><td> Sigma A-8960</td><td> lofox(lOOmM)</td><td> lx(0.1 mM)</td><td> 500 pl</td>

<td> PIO (50 pg)</td><td> R&amp;D220BD</td><td> lOpg/mlm 4mMHCl+ 0.1% BSA</td><td> 10 ng/ml</td><td> 500 μΐ</td>

<td> EGF(200pgj</td><td> Sigma E-9644</td><td> 10pg/mlin 10mMHAc + 0.1% BSA</td><td> 10 ng/ml</td><td> 500 μΐ</td>

The above-composition is a perfusate that may be used at a variety of temperatures to perfuse placenta. It should be noted that additional components such as antibiotics, anticoagulant and other growth factors may be used in the perfusate or culture media.

<img file="CA2856986C_D0038.tif" />

described herein. Indeed, various modifications of the invention in addition to those

<img file="CA2856986C_D0039.tif" />

description. Such modifications are intended to fell within the scope of the appended claims.

The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention.