Use of neurotoxin therapy for treatment of prostate disorders

FIELD OF THE INVENTION

0001The present invention relates generally to the treatment of prostate disorders, for example, benign prostatic hyperplasia (BPH) and prostatitis. This is accomplished by administering a composition that includes at least one neurotoxic compound or by conventional therapies.

BACKGROUND OF THE INVENTION

0002Many medical conditions in urology are rooted in a spastic dysfunction of the sacral reflex arcs. Examples of such conditions include pelvic pain (e.g., interstitial cystitis, endometriosis, prostatodynia, urethral instability syndromes), pelvic myofascial elements (e.g., levator sphincter, dysmenorrhea, anal fistula, hemorrhoid), urinary incontinence (e.g., unstable bladder, unstable sphincter), prostate disorders (e.g., BPH, prostatitis, prostate cancer), recurrent infection (secondary to sphincter spasticity), and urinary retention (secondary to spastic sphincter, hypertrophied bladder neck) and neurogenic bladder dysfunction (e.g., Parkinson's Disease, spinal cord injury, stroke, multiple sclerosis, spasm reflex).

0003The prostate, is a partially glandular and partially fibromuscular gland of the male reproductive system. During aging, the prostate tends to enlarge (hypertrophy). This prostatic enlargement can lead to urethral obstruction and voiding dysfunction.

0004Prostatic enlargement is a common occurrence in older men. Lytton <i>et al.</i> (Lytton, B., Emery, J.M. and Harvard, B.M. [1973] 99: 639-645) estimated that a 45 year old male had a 10% risk of prostate surgery by age 70. The U.S. Census Report estimates that there are 30 million people today over age 65. This segment of the population is projected to rise to 50 million over the next 30 years. Therefore, the number of men with prostatic enlargement also will increase. According to draft reports of the National Kidney and Urologic Disease Advisory Board, 425,000 prostatectomies were performed in the United States in 1989. Based on population growth estimates, the number of prostatectomies performed annually will rise to 800,000/year by the year 2020.

0005The urethra passes through the prostate (prostatic urethra) as it courses to the external urethral orifice. The prostate has five distinct lobes that are apparent at 12 weeks in the human fetus (<nplcit id="ncit0001" npl-type="s"><text>Lowsley, O.S. Am. J. Anat. [1912] 13 : 299-349</text></nplcit>.). Although the lobular branching found in the fetus is not visible in the prepubescent prostate, the lateral middle anterior and posterior lobes are used to describe the enlarged prostate.

0006A more recent viewpoint is that the prostate also is comprised of several morphologically distinct zones (<nplcit id="ncit0002" npl-type="s"><text>McNeal, J. Urol. Clin. North Am. [1990] 17(3): 477-486</text></nplcit>). The majority of the glandular volume is composed of the peripheral zone (~70-75%). The remainder of glandular volume is divided into the central zone (~20-25%), the transition zone (~5-10%) and the periurethral glandular zone (~1%).

0007McNeal (1990) reported that BPH develops in the transition zone and the periurethral glandular zone. BPH nodules develop either within or immediately adjacent to the preprostatic sphincteric zone. The transition zone is a small region close to the urethra intimately related to the proximal urethral sphincter. The stroma of the transition zone is dense and compact, and is unusually susceptible to neurologically-induced disturbances of growth control. Its glands penetrate the sphincter, while sphincter muscle fibers penetrate the transition stroma. The periurethral glandular zone has a similar urogenic sinus origin as the transition zone.

0008BPH may be associated with increased amounts of stroma relative to epithelium (<nplcit id="ncit0003" npl-type="s"><text>Bartsch, G., Muller, H. R., Oberholzer, M., Rohr, H., P., J. Urol. [1979] 122: 487-491</text></nplcit>). A significant portion of the stroma is smooth muscle (McNeal, 1990) which is under sympathetic nervous control. The contractile properties of this smooth muscle could account for the dynamic component of obstruction in BPH (<nplcit id="ncit0004" npl-type="s"><text>Bruschini, H. et al. [1978] Invest. Urol. 15(4): 288-90</text></nplcit>; <nplcit id="ncit0005" npl-type="s"><text>Lepor, H. [1990] Urol. Clin. North Am. 17(3): 651-658</text></nplcit>).

0009In addition to sympathetic control of prostatic stroma, the prostate is highly innervated. The prostate nerve fibers enter the prostate from the posterior lateral aspect, with a concentration of ganglia near the junction between the prostate and the seminal vesicles (Maggi, C.A., ed. [1993] Nervous control of the Urogenital System, Harwood Academic Publishers; <nplcit id="ncit0006" npl-type="s"><text>Higgins, J.R.A. and Gosling, J.A. [1989] Prostate Suppl. 2: 5-16</text></nplcit>). Acetylcholine (ACH), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP) and noradrenaline fibers have been described in this gland. A rich plexus of ACH-positive nerve cell bodies is associated with secretory acini in all parts of the gland. Some of the ACH fibers also contain NPY neurons. VIP-containing neurons have been found associated with ACH-containing nerve cell bodies. Occasional neurons have been found between the ACH-staining nerve fibers, suggesting that both NPY and noradrenergic neurons supply smooth muscle (<nplcit id="ncit0007" npl-type="s"><text>Higgins, J.R.A. and Gosling, J.A. [1989] Prostate Suppl. 2: 5-16</text></nplcit>).

0010Autonomic nerves are distributed evenly between the central and peripheral zones of the prostate (<nplcit id="ncit0008" npl-type="s"><text>Higgins, J.RA. and Gosling, J.A. [1989] Prostate Suppl. 2: 5-16</text></nplcit>). Peripheral neuronal control is similar. In addition, there is no difference in the type of nerve fibers found associated with either epithelial or stromal elements of the gland.

0011The anatomical studies of nerve fiber types in the prostate, coupled with other studies of innervation of prostatic stroma (<nplcit id="ncit0009" npl-type="s"><text>Brushing H., Schmidt, R.A., Tanagho, E.A., [1978] Invest. Urol. 15(4): 288-290</text></nplcit>; <nplcit id="ncit0010" npl-type="s"><text>Watanabe, H., Shima, M., Kojima, M., Ohe, H.L. [1989] Pharmacol. Res. 21(Suppl 2): 85-94</text></nplcit>) suggest that cholinergic innervation influences epithelial behavior, while adrenergic innervation influences stromal tonus (excitability). These observations have provided a rationale for the use of, for example, alpha blockers in the treatment of BPH. The effects of alpha blockers (<nplcit id="ncit0011" npl-type="s"><text>Downie, J.W. and Bialik, G.J. [1988] J. Pharmacol. Exp. Ther. 246(1): 352-358</text></nplcit>) can also account for improvements in symptoms of BPH as a result of dampening of dysfunctional striated sphincter behavior by the alpha blockers.

0012Studies have also shown that there are several tachykinins (for example, substance P [SP], calcitonin gene related peptide [CGRP], neurokinin A, bradykinin, and nerve growth factor [NGF]) that can influence the tonus of smooth muscle (<nplcit id="ncit0012" npl-type="s"><text>Hakanson, et al., [1987] Neuroscience 21(3): 943-950</text></nplcit>). Neurotransmitter receptors have been quantified throughout the prostate (e.g., NPY, VIP, SP, leu-enkephalin (L-enk), met-enkephalin, 5-HT, somatostatin, acetylcholinesterase positive fibers (ACTH), and dopamine beta-hydroxylase (DBH) (Crowe, R, Chapple, C.R, Bumstock, G. The Human Prostate Gland: A Histochemical and Immunohistochemical Study of Neuropeptides, Serotonins, Dopamine beta-Hydroxylase and Acetylcholinesterase in Autonomic Nerves and Ganglia). There is some variation in receptor density at different prostatic sites in benign prostatic hyperplasia.

0013Changes in electrophysiologically recorded cellular behavior and in concentration of neuropeptides within the spinal cord have been shown to be a secondary consequence of mechanical pinch to the tail muscles of a rat, catheter stimulation of the posterior urethra, and electrostimulation of a peripheral nerve. Dyssynergia between the detrusor and the urethral sphincter is a significant finding in prostatodynia patients. Denervation of the prostate has been shown to produce dramatic changes within the prostatic epithelium. Thus there is evidence that experimentally induced alterations in neurological influences can be produced in the sacral, spinal cord, bladder or urethra through mechano-, electro-, chemical or thermal (microwave, laser) methods to change irritative behavior. However, there have been no known attempts to use neurotoxins for therapeutic applications.

0014There is poor correlation between the degree of prostatic enlargement and the severity of symptoms. While 80% of men age 70 show BPH on transrectal ultrasound scans, only 20% seek surgery (<nplcit id="ncit0013" npl-type="s"><text>Coffey, D.S. and Walsh, P.C. [1990] Urol. Clin. North Am. 17(3): 461-475</text></nplcit>), the treatment of choice for BPH (<nplcit id="ncit0014" npl-type="s"><text>Fowler, F.J. Jr., Wennberg, J.E., Timothy, R.P. [1988] J. Amer. Med. Assoc., 259(20): 3022-3028</text></nplcit>). Symptoms of irritation may far exceed symptoms expected based on the size of the prostate. Symptoms may improve after surgical treatment of BPH by procedures such as transurethral resection of the prostate (TURP) (<nplcit id="ncit0015" npl-type="s"><text>Christensen, Aagaard, M.M. J., Madsen, P.O. [1990] Urol. Clin. North Am. 17(3): 621-629</text></nplcit>), balloon dilation (<nplcit id="ncit0016" npl-type="s"><text>Dowd, J.B. and Smith, J.J. III [1990] Urol. Clin. North Am. 17(3): 671-677</text></nplcit>), or prostatic hyperthermia (<nplcit id="ncit0017" npl-type="s"><text>Baert, L., Ameye, F., Willemen, P., et al., [1990] J. Urol. 144: 1383-1386</text></nplcit>). However, symptoms persist in as many as 15% of all BPH patients (<nplcit id="ncit0018" npl-type="s"><text>Baert, L., Ameye, F., Willemen, P., et al., [1990] J. Urol. 144: 1383-1386</text></nplcit>; <nplcit id="ncit0019" npl-type="s"><text>Wennberg, J.E., Mullly, A.G., Hanley, D., Timothy, R.P., Fowler, F. J., Roos, R.P., Barry, M.J. et al., [1988] J. Amer. Med. Assoc. 259: 3027-3030</text></nplcit>). Up to 25% of BPH patients have secondary procedures in long term follow-up studies, suggesting that surgical approaches do not address the fundamental mechanisms that produce BPH, i.e., the faulty neurological influence (control mechanism) on the integrity of the lower urinary tract.

0015The need for repeated surgeries, the morbidity and mortality associated with TURP and the cost of surgery have led to the development of some non-surgical approaches such as androgen ablation (<nplcit id="ncit0020" npl-type="s"><text>McConnell, J.D., [1990] Urol. Clin. North Am. 17(3): 661-670</text></nplcit>) and the use of alpha blockers discussed above, but few medical or surgical treatments to date have produced a restoration of void behavior to normal state (flow rate of about 25cc/sec and void volume of about 400cc).

0016The present invention uses neurotoxin which is a botulinumtoxin, to modulate prostate disorders. For example, such methods can be used to treat BPH and related conditions such as prostatitis. The instant invention also may remove triggers of changes in the CNS by non-chemical methods including biofeedback, or by chemical methods that treat BPH and other urological conditions by the administration of substances that block various neurological activities, such as, for example, selected neurotoxins.

OBJECTS AND SUMMARY OF THE PRESENT INVENTION

0017In accordance with one aspect of the present invention, there is provided the use of a botulinum toxin in the preparation of a pharmaceutical composition for treating a prostate disorder in a mammal. It is preferred that the botulinum inhibits synaptic function. Such inhibition produces selective denervation, and, for example, atrophy of the prostate and reversal of irritative symptoms associated with prostatic enlargement. In one embodiment of the instant invention, the neurotoxin induces dysfunction of the presynaptic neuronal terminal by specific binding and blockade of acetylcholine release at myoneural junctions. Such a neurotoxin can be, for example, botulinum toxin type A (Botox, Allergen).

0018Preferably, the neurotoxin is safe, highly selective and easy to deliver, including when combined with other therapies. It is also inexpensive, and can be used on an out-patient basis. Other useful neurotoxins include capsaicin, resinoferatoxin and α-bungotoxin. Delivery of the neurotoxin can be by any suitable means. A convenient and localized method of delivery is by injection.

0019A therapeutically effective amount of the neurotoxin is the dosage sufficient to inhibit neuronal activity for at least one week, more preferably one month, most preferably for approximately 6 to 8 months or longer. Dosing can be single dosage or cumulative (serial dosing), and can be readily determined by one skilled in the art. Neurotoxin can be delivered serially (i.e., one time per month, one time per every six months) so that the therapeutic effect can be optimized. Such a dosage schedule is readily determined by one skilled in the art based on, e.g., patient size and the condition to be treated, and will depend on many factors, including the neurotoxin selected, the condition to be treated, the degree of irritation, and other variables. One suggested course of treatment for BPH is 200 units every three days up to the LD50 for Botox or about 2500 units.

0020The aforementioned methods of treatment should be particularly useful for the long-term control of prostate disorders e.g., the symptoms of prostatic enlargement, without the need for surgical intervention. Furthermore, the methods of the instant invention provide for control of neurological-urological disorders, e.g., BPH and related conditions, in a highly selective manner, without the potential side effects and treatment failures associated with current treatment modalities.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

0021One example of prostate disorder with which the present invention is concerned is prostate enlargement. The prostatic enlargement that can be treated according to the methods of the instant invention can be of any etiology. The instant invention is particularly suited for the treatment of prostatic hyperplasia, especially benign prostatic hyperplasia. The present invention can also be used for the treatment of enlargement of the prostate with inflammation (prostatitis), particularly abacterial prostatitis. In addition, the methods of the instant invention can be used for the treatment of prostatodynia, and prostate cancer.

0022Without being bound by theory, the basis for the treatment of the neurological-urological conditions is the removal or modulation of the neural basis for the dysfunctional regulation of the affected tissue. For example, the modulation of the neural basis of prostate glandular dysfunction can be accomplished by any non-surgical means known in the art. Such means can include, for example, biofeedback, α-blockers, pharmacological methods, and the use of one or more neurotoxins to inhibit synaptic function in the affected gland. It is preferred that the neurotoxin cause long-lasting inhibition of synaptic function, preferably greater than one week, more preferably greater than one month, most preferably six to eight months or longer. Such neurotoxins can include, for example, capsaicin, resinoferatoxin, α-bungotoxin, terodotoxin and botulinum toxin. Botulinum toxin is a required neurotoxin according to the instant invention, particularly botulinum toxin A, more particularly Botox (Allergen).

0023The toxin can be formulated in any pharmaceutically acceptable formulation in any pharmaceutically acceptable form. Such forms and formulations include liquids, powders, creams, emulsions, pills, troches, suppositories, suspensions, solutions, and the like. The toxin can also be used in any pharmaceutically acceptable form supplied by any manufacturer.

0024In a preferred embodiment in accordance with the method of the instant invention, the neurotoxin is botulinum toxin type A. Therapeutically effective amounts of botulinum toxin can be any amounts or doses that are less than a toxic dose, for example, less than about 3000 IU/70 kg male, preferably between 104 IU/70 kg male to 1200 IU/70 kg. The dosages can be given as a single dose, or as divided doses, for example, divided over the course of four weeks.

0025The neurotoxins of the instant invention can be administered by any suitable means. In the preferred embodiment of the invention, botulinum toxin is administered by injection. For example, the neurotoxin can be injected urethroscopically into the prostate with 200 IU with single or serial dosing. Preferably, the neurotoxin is injected every three days until a therapeutic effect is achieved or up to about 2500 units.

0026The following techniques are used in this invention:

Tissue Preparation for Light Microscopy

0027Tissues are fixed in 6% paraformaldehyde in 0.1 M phosphate buffer, pH 7.2, for 24 hours, dehydrated in graded alcohol and xylene, and embedded in paraffin. Sections are cut and stained with appropriate stains, such as hematoxylin/eosin.

Tissue Preparation for Electron Microscopy

0028Tissues are collected and fixed in 2.5% glutaraldehyde in 0.1 M phosphate buffer, pH 7.2, for 1 hour at 4°C, then incubated with 0.1% osmium tetroxide for 1 hour and embedded in EPON. Ultrathin sections (80 nm) are prepared and stained with lead citrate/uranyl acetate and examined with an electron microscope (Philips, model 201).

Tunel Stain for Apoptosis

0029The tissue is fixed and embedded as described above. The tissues are deparaffinized and reacted with Proteinase K (Boehringer). They are further treated with peroxidase and TDT enzyme and placed in a humidifier set at 37°C for one hour. The sections are washed and anti-digoxigenin-peroxidase is added for 30 minutes, followed by staining with nickel-DAB (diaminobenzene).

Immunohistochemistry Studies

0030The presence of the neuropeptides VIP, SP, NPY, L-Enk and calcitonin gene-related peptide (CGRP) as well as the expression of transforming growth factor beta (TGF-beta), transforming growth factor alpha (TGF-alpha), epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) are determined in prostatic tissues using appropriate monoclonal antibodies. Use of neurotoxins results in prostatic atrophy, which should be renected by lower levels of growth factors in treated prostatic tissue.

0031Sections are incubated overnight at room temperature with primary antibodies followed by immunostaining with avidin-biotin-peroxidase (Vectastain Elite ABC, Vector Labs, USA). Rabbit polyclonal antiserum against the neurotransmitters VIP, CGRP, SP,NPY and L-Enk (Peninsula Labs, USA) is used in these preparations, at dihitions of 1:8000 to 1:12,000. Immunocytochemical controls consist of preabsorbing the primary antiserum with appropriate antigen, or their substitution with normal serum (<nplcit id="ncit0021" npl-type="s"><text>Blasi, J., Chapman, E.R., Yamaskai, S., Binz, T., Niemann, H and Jahn, R. [1993] The EMBO Journal 12: 4821-4828</text></nplcit>; <nplcit id="ncit0022" npl-type="s"><text>Black, J.D. and Dolly, J.O. [1986] J. Cell Biol. 103; 535-544</text></nplcit>; <nplcit id="ncit0023" npl-type="s"><text>Linial, M. [1995] Is. J. Med. Sci. 31: 591-595</text></nplcit>). After mounting on slides, sections are counterstained with eosin, dehydrated and coverslipped.

Western Blot Analysis of Growth Factor Expression

0032Treated and untreated prostate cell homogenates are examined for expression of growth factors by Western blot analysis. Cell homogenate protein is separated by electrophoresis on SDS-PAGE (7%), then transferred electrophoretically overnight to nitrocellulose paper (<nplcit id="ncit0024" npl-type="s"><text>Towbin, H., et al., [1979] Proc. Nat. Acad. Sci. 76(9): 4350-4379</text></nplcit>). The nitrocellulose paper is soaked for one hour at room temperature in 0.5% non-fat dry milk dissolved in phosphate buffered saline, and further soaked overnight at 4°C in blocking solution (2% bovine serum albumin in 10 mM Tris/0.15 M NaCl/ 0.1% sodium azide, pH 7.4). The nitrocellulose membranes are incubated with antibodies (IgG fractions of anti-TGF-beta, anti-TGF-alpha, anti-EGF and anti-bFGF) purified by protein A (1 x 10⁶ cpm/ml) in blocking buffer for 1 hour. The membrane is washed with PBS containing Nonidet P-40 between incubations. X-O-mat AR2 film (Kodak) is exposed to the membrane at -70°C and films are developed to examine the expression of growth factors.

Determination of c-fos and c-myc Expression

0033Expression of c-fos and c-myc in treated and untreated prostatic tissue is determined by Northern blot analysis as follows. Tissue is homogenized in lysis buffer for 15 seconds or until the tissue homogenizes. Sodium acetate is added and the solution is mixed by swirling. An equal volume of water-saturated phenol is added and mixed by inversion, followed by addition of chloroform/isoamyl alcohol. The solution is vortexed vigorously for 30 seconds, and allowed to settle on ice for 15 minutes. The solution is centrifuged for 10-20 minutes at 4°C. After centrifugation, the aqueous phase is carefully aspirated and placed in a new polypropylene tube. One volume of isopropanol is added and the solution is mixed by swirling. The solution is placed in a -20°C freezer for at least 60 minutes to precipitate RNA. After precipitation, the tube is centrifuged for 10 minutes, and the supernatant is decanted, leaving the RNA pellet. One ml of ethanol is added, and the tube is centrifuged for an additional 10 minutes. The aqueous phase is discarded, and the pellet is washed with 100% ethanol by vortexing. The RNA pellet is redissolved in 0.4 ml of lysis buffer. The RNA is reprecipitated by the addition of 100% ethanol and incubation at -20°C freezer for at least 60 minutes. The solution is centrifuged and the supernatant discarded. RNA concentration is determined by diluting 5 µL of sample into 995 µL of DEPC water and measuring the ratio of absorbance at 260/280 nm.

0034The following examples are provided by way of describing specific embodiments without intending to limit the scope of the invention in any way.

Example 1

Denervation of the Prostate

0035Unilateral denervation of the prostate is carried out by removal of the pelvic ganglia, which overlie the prostate of the rat. This approach preserves the functional integrity of the bladder and posterior urethra and removes the possibility for artifact arising from major disturbances in blood flow or micturation. Control animals undergo sham operations without concurrent denervation of the prostate. After denervation, the animals are allowed to recover and maintained prior to collection of the prostate. The prostate is preserved, prepared for light microscopy and examined histologically. The major findings are (1) reduced epithelial cell height primarily due to a decrease in the clear supranuclear zone (due to a reduction in the amount and size of the apical cisternae and the endoplasmic reticulum); (2) major changes in protein expression on SDS gel electrophoresis (the endoplasmic reticulum is important in protein synthesis) (3) modest reduction in the number of secretory granules; (4) an increase in intracellular vacuoles, intercellular empty spaces and reduction in microvilli on the cell surface; and (5) a significant increase in nerve growth factor (NGF) content ipsilateral to the denervation relative to the control group (188 ± 10 vs. 46 ± 20 vs. 29 ± 16 pg/g wet tissue (± SD) NGF is known to influence only sympathetic and sensory neurons. N = 15 in both the control and experimental groups.

Example 2

Effect of Neurotoxin Injection on Normal Prostate: Rat Prostate

0036Rats were randomly assigned into three groups. The first group received a single acute dose of Botulinum toxin type A (Botox, Allergen) of 5, 10 or 15 IU. These animals were sacrificed one week after injection. The second group received a series of 4 weekly injections of 5 IU of Botulinum toxin and were sacrificed at 5 weeks. Control rats received saline injections. Injections were performed as single or serial injections into the left and/or right ventral lobe of the prostate. Note that an injection of methylene blue into one lobe of the rat prostate showed immediate diffusion into the opposite lobe. Thus, there was communication between the prostate lobes and therefore the contralateral lobe could not be used as a true comparative control.

0037The weight of each prostate ventral lobe collected from healthy animals was approximately 0.50 gram. All toxin-treated animals showed shrinkage of prostate volume, first in the injected lobe, and with subsequent injections, reduction in the overall volume. After four serial injections, the left prostate lobe weighed 0.12-0.17 gram, while the right lobe weighed 0.10-0.14 grams. This represented a reduction of over two-thirds of the original size.

Example 3

Effect of Neurotoxin Injection on Urological Dysfunctions: Human Data

0038Three patients with recalcitrant voiding dysfunction were treated with injections of botulinum toxin (Botox) as follows. Patient 1 was a 47-year-old male who was incontinent secondary to an injury sustained at the cervical vertebrae (level C6-C7) sustained 14 months previously. Urodynamics on presentation revealed a bladder capacity of 30 cc and a weak sphincter (peak urethral pressure of 40 cm water). He had failed multiple pharmacological regimes and was intolerant to penile clamp/condom devices.

0039He received four weekly 200 IU botulinum toxin injections into the bladder neck for total dose of 800 IU. Post-injection, his bladder capacities ranged from 300-400 cc with oxybutinin and 150-200 cc without oxybutinin. Peak bladder pressures pre-injection had been 200-cm water, compared to post injection bladder pressures of 40 cm of water. The patient was continent with a penile clamp after treatment with botulinum toxin. In addition, walking and erections improved due to reduced bladder spasticity.

0040Patient 3 was a 65 year old male with disabling perineal pain following radiation treatment for prostatic cancer. The patient had failed medical therapy. He was treated with one 200 IU injection of botulinum toxin into the external urethral sphincter. The patient experienced a dramatic relief of testicle pain and had far less severe pain in the shaft of the penis. Erections were not affected.

Example 4

Determination of Smallest Effective Dose

0041Rats are injected in the prostate ventral lobes with single and serial doses of botulinum toxin (Botox) The prostates are harvested at different time intervals to determine the smallest effective dose, as well as the morphological and physiological changes taking place with time. The smallest effective dose is defined as that dose that would demonstrate a decrease in prostate volume.

0042To assess the response to electrical field stimulation, preparations are mounted between two platinum electrodes placed in the organ bath. The tension of the preparations is adjusted. Transmural stimulation of nerves is performed using a Danted Neuromatic 2000 Stimulator delivering single square-wave pulses at supramaximal voltage with a duration of 0.8 milliseconds at a frequency of 0.5 to 80 hertz. The polarity of the electrodes is changed after each pulse by means of a polarity-changing unit. The train duration is five seconds and the train interval 120 seconds. Isometric tension is recorded by using a Gould thermo-array 8-channel recorder. Separate experiments are performed to determine the preload tension producing optimal responses. In addition, the effect of the electric field stimulation in the presence of different concentrations of individual neuropeptides is determined. These neuropeptides are 10-20 µM adrenaline, 10 µM clonidine, 5-50 mM regitine, 10 nM - 0.1 µM acetylcholine, 1 - 3 µM atropine, 1 nM - 10 µM nifedipine, 1 - 10 nM VIP and 1 - 250 nM NPY. The effect of nitroprusside (a nitric oxide releasing substance) and methylene blue (a guanylate cyclase inhibitor) on prostate tone and contraction resulting from field stimulation also is examined in these tissues.

Example 5

Effect of Botulinum Toxin on Rat Prostatic Tissue: Comparison of Hormonally Intact Rats to Hormonally Deprived Rats

0043To determine if there is any interaction between the neurotoxin and testicularly-derived hormones, studies are performed which will examine the interaction of the neurotoxin with hormonal components. These studies will compare prostatic tissue treated with botulinum toxin harvested from rats that have undergone orchiectomy (hormonally depleted rats) and prostatic tissue from rats treated with botulinum toxin that did not undergo orchiectomy. Fifty-two age-matched rats are treated as described below. Four healthy rats will undergo a sham operation consisting of anesthesia induction, exposure of the prostate and injection of 0.2 cc saline into the left ventral lobe of the prostate. Three rats are given bilateral orchiectomy with no injection to the prostate (hormonally depleted controls), five rats will have orchiectomy and injection of 0.2 ml saline in the left ventral lobe (hormonal depletion + surgical stress control). Four groups of rats receive botulinum injections of 0.5 IU, 1.0 IU, 1.5 IU and 2.5 IU only (hormonally intact experimental rats). Sixteen rats undergo bilateral orchiectomy. Eight of these rats are treated with a single injection of 2.5 IU botulinum toxin into the left ventral lobe 5 weeks after surgery. All rats are sacrificed after six weeks, and the harvested prostate is prepared for examination as described above. A similar atrophic effect on glandular epithelium is expected.

Example 6

Effects of Botulinum Toxin on Patients

0044Patients affected by benign prostatic hyperplasia, abacterial prostatis, or prostatodynia are studied both before and after treatment with botulinum toxin. Patients are eligible for inclusion in this study if they are affected by BPH between the ages of 40 and 80, or if they are between 25 and 60 and have been diagnosed with abacterial prostatitis or prostatodynia. Preferred patients are those who are not good surgical candidates. Patients are evaluated prior to treatment by determination of prostate specific antigen levels (PSA), evaluation of urodynamic parameters (cystometrogram, urethral pressure profile and flowmetry), determination of American Urological Association (AUA) symptom score (<nplcit id="ncit0025" npl-type="s"><text>Barry, M.J., et al., [1992] J. UroL, 148: 1549-1557</text></nplcit>), maintenance of a voiding diary, and examination of the prostate by transrectal ultrasound with biopsy (for BPH patients only). One week after initial evaluation is completed, the patient is injected urethroscopically with 200 IU of botulinum toxin as either single unilateral injections, serial unilateral injections or bilateral injections. BPH patients are treated by TURP or undergo control TURP-biopsy 7 days after single injection or 5 weeks after serial injections. The harvested prostatic tissues are prepared for examination as described in Examples 1,2, 3, and 7-10. The patients are reevaluated after injection using the same parameters examined during the initial evaluation.

0045The foregoing description of the invention is exemplary for purposes of illustration and explanation. It will be apparent to those skilled in the art that changes and modifications are possible without departing from the scope of the invention. It is intended that the following claims be interpreted to embrace all such changes and modifications.