Protective Effect of Tadenan of Bladder Function Secondary to Partial Outlet Obstruction

Role of Phytotherapy in the Management of BPH: A Summary of the Literature

Benign prostatic hyperplasia (BPH) describes the non-malignant enlargement of the prostate. It is both common and growing in incidence. Treatment is multimodal, involving conservative, medical, and surgical interventions. This review aims to examine the evidence base for phytotherapies, specifically analyzing their role in treating lower urinary tract symptoms (LUTS) attributable to BPH. A literature search was completed, specifically looking for randomized control trials (RCTs) and systematic reviews involving phytotherapy treating BPH. Specific emphasis was placed on exploring substance origin, the proposed mechanism of action, evidence of efficacy, and the side-effect profile. Several phytotherapeutic agents were evaluated. These included serenoa repens, cucurbita pepo, and pygeum Africanum, among others. For most of the reviewed substances, only modest effectiveness was reported. Generally, though, all treatments were tolerated well with minimal side effects. None of the treatments discussed in this paper form part of the recommended treatment algorithm in either European or American guidelines. We, therefore, conclude that phytotherapies, in the treatment of LUTS attributable to BPH, do provide a convenient option for patients, with minimal side effects. At present, however, the evidence for the usage of phytotherapy in BPH is inconclusive, with some agents having more backing than others. This remains an expansive field of urology whereby there is still more research to be done.

Review of the experience and evidence of Pygeum africanum in urological practice

CONTEXT

Pygeum africanum(P. africanum) is still being employed in urology practice for the treatment of lower urinary tract symptoms secondary to benign prostate hyperplasia.

EVIDENCE ACQUISITION

A non-exhaustive review has been carried out about P. africanum, its mechanisms of action "in vitro" as well as "in vivo", clinical trials and routine clinical practice.

EVIDENCE SYNTHESIS

The conclusions of the review and the reflections of the authors on the use of P. africanum are described.

CONCLUSIONS

Although with an evidence level IV (based on expert opinion) the use of P. africanum seems to be an option in the urological therapeutic arsenal.

Role of puborectalis muscle in the genesis of urethral pressure

PURPOSE

The internal (smooth muscle) and the external (rhabdosphincter striated muscle) urethral sphincters have important roles in the genesis of urethral closure pressure. The U-shaped pelvic floor puborectalis muscle is important in the closure of anal and vaginal orifices in humans. We defined the contribution of the puborectalis to urethral pressure.

MATERIALS AND METHODS

A total of 11 female rabbits were anesthetized and prepared to measure urethral, vaginal and anal canal pressure using manometric methods. Pressure was recorded at rest, after administration of pharmacological agents and during electrical stimulation of the puborectalis and rhabdosphincter sphincter muscles. Phenylephrine, sodium nitroprusside (Sigma-Aldrich®) and rocuronium bromide (PharMEDium, Lake Forest, Illinois) were used to define the relative contribution of smooth and striated muscles to urethral pressure. Histology of the pelvic floor hiatus was also studied.

RESULTS

At rest mean ± SEM maximum urethral pressure was 13 ± 6 mm Hg. Sodium nitroprusside (50 μg/kg) infusion resulted in a 30% to 40% decrease in resting urethral pressure (mean 7.2 ± 0.2 mm Hg). Phenylephrine produced a dose dependent increase in urethral pressure (mean 17 ± 6, 25 ± 5 and 29 ± 6 for 5, 10 and 50 μg/kg intravenously, respectively). Electrical stimulation of the puborectalis muscle induced a stimulus dependent increase in urethral, vaginal and anal canal pressure. On the other hand, rhabdosphincter stimulation induced a stimulus intensity dependent increase in urethral pressure only. The increase in urethral pressure after puborectalis muscle stimulation was more than twofold higher than after rhabdosphincter stimulation.

CONCLUSIONS

Our data prove that the puborectalis, a component of the pelvic floor muscles, is an important contributor to urethral pressure in the rabbit.

Androgens and estrogens in benign prostatic hyperplasia: past, present and future

Benign prostatic hyperplasia (BPH) and associated lower urinary tract symptoms (LUTS) are common clinical problems in urology. While the precise molecular etiology remains unclear, sex steroids have been implicated in the development and maintenance of BPH. Sufficient data exists linking androgens and androgen receptor pathways to BPH and use of androgen reducing compounds, such as 5α-reductase inhibitors which block the conversion of testosterone into dihydrotestosterone, are a component of the standard of care for men with LUTS attributed to an enlarged prostate. However, BPH is a multifactorial disease and not all men respond well to currently available treatments, suggesting factors other than androgens are involved. Testosterone, the primary circulating androgen in men, can also be metabolized via CYP19/aromatase into the potent estrogen, estradiol-17β. The prostate is an estrogen target tissue and estrogens directly and indirectly affect growth and differentiation of prostate. The precise role of endogenous and exogenous estrogens in directly affecting prostate growth and differentiation in the context of BPH is an understudied area. Estrogens and selective estrogen receptor modulators (SERMs) have been shown to promote or inhibit prostate proliferation signifying potential roles in BPH. Recent research has demonstrated that estrogen receptor signaling pathways may be important in the development and maintenance of BPH and LUTS; however, new models are needed to genetically dissect estrogen regulated molecular mechanisms involved in BPH. More work is needed to identify estrogens and associated signaling pathways in BPH in order to target BPH with dietary and therapeutic SERMs.

Effect of hydrogen peroxide on rabbit urinary bladder citrate synthase activity in the presence and absence of a grape suspension

PURPOSE

The etiology of obstructive bladder dysfunction includes free radical damage to mitochondria. Feeding rabbits a standardized grape suspension protects the ability of the bladder to contract and empty in part by preventing mitochondrial damage, thus maintaining smooth muscle and mucosal metabolism. The objective of the current study is to determine the direct effect of this grape suspension on the response of mitochondria to the oxidative effects of hydrogen peroxide.

MATERIALS AND METHODS

Six male rabbits were anesthetized with sodium pentobarbital and the bladders excised. Four full thickness strips were obtained for contractile studies and the balance separated into smooth muscle and mucosa compartments by blunt dissection. The effect of hydrogen peroxide on the contractile response to field stimulation was quantitated. Each tissue was homogenized and the effects of increasing concentrations of hydrogen peroxide in the presence and absence of grape suspension on citrate synthase activity was determined.

RESULTS

Citrate synthase activity was significantly higher in the mucosa than in the muscle. The grape suspension had no effect on control citrate synthase activity. However, the grape suspension provided significant protection of both smooth muscle and mucosal citrate synthase activity.

CONCLUSIONS

These studies support the conclusion that the grape suspension provides direct protection of mitochondrial function.

Pygeum africanum: effect on oxidative stress in early diabetes-induced bladder

OBJECTIVE

To evaluate the effect of Pygeum africanum on oxidative stress and functional changes of the bladder after diabetes induction.

MATERIALS AND METHODS

Thirty-two adult Wistar male rats were treated daily for 8 weeks and grouped as follows: Control group (n = 6), Streptozotocin-induced diabetic group (n = 10), diabetes plus P. africanum group (n = 10), and control plus P. africanum group (n = 6). After diabetes induction for 4 weeks, the diabetes plus P. africanum and control plus P. africanum groups were fed with P. africanum (100 mg/kg, orally) in peanut oil for another 4 weeks. The catalase, superoxide dismutase activity, and malondialdehyde levels were measured as a marker of lipid peroxidation. The levels of inducible nitric oxide synthase were also evaluated. Urodynamic studies were performed to evaluate the functional changes of diabetic bladders after P. africanum treatment.

RESULTS

The catalase and superoxide dismutase activities significantly increased (P < 0.05) and maleic dialdehyde levels significantly decreased from diabetic plus P. africanum group compared with diabetic group (P < 0.05). Immunohistochemical studies showed a significantly decreased number of inducible nitric oxide synthase-positive cells in diabetic plus P. africanum group compared with diabetic group (P < 0.05). In diabetic plus P. africanum group, maximal bladder volume significantly decreased, while bladder pressure and maximal bladder pressure significantly increased compared with diabetic group (P < 0.05).

CONCLUSIONS

Early treatment with P. africanum could effectively suppress the oxidative stress status in diabetic bladder and may slow down the process of diabetic cystopathy.

Combined use of melatonin and terazosin restores bladder contractility in rabbits with partial outlet obstruction

OBJECTIVES

To investigate the effects of terazosin and melatonin on isolated rabbit bladder strips after partial bladder outlet obstruction and determine responses to agonist-induced contractility and changes in oxidant-antioxidant system.

METHODS

We created partial bladder outlet obstruction in 5 groups of rabbits, each containing 8. Rabbits with sham operation (group 1) received no drug treatment. Similarly, animals in group 2 underwent partial bladder outlet obstruction and received no drug treatment. Rabbits in groups 3 were administered 5 mg/day oral terazosin, and rabbits in group 4 received 10 mg/kg/day melatonin intraperitoneally. Animals in group 5 received both terazosin and melatonin. We removed their bladders and performed histopathological and biochemical measurements. We assessed tissue malondialdehyde and antioxidant enzyme activity levels and recorded in vitro contractility response to KCl in isolated organ baths.

RESULTS

The thickness of muscularis propria was significantly increased in group 2 compared with all other groups. KCl-evoked contractions after partial outlet obstruction were significantly impaired in group 3 and 4 animals receiving terazosin and melatonin, respectively. However, combined use of melatonin and terazosin in group 5 showed contractility responses similar to sham-operated animals (P <0.05). Melatonin administration to groups 4 and 5 showed decreased levels of lipid peroxidation. Similarly, animals receiving melatonin and melatonin plus terazosin showed statistically significant increase in antioxidant enzyme activities.

CONCLUSIONS

In the present study, we showed that oxidative stress induced by partial bladder outlet obstruction can be successfully antagonized by the potent antioxidant melatonin, and its combined use with an alpha-antagonist such as terazosin may restore in vitro contractility.

A critical review of the pharmacology of the plant extract ofPygeum africanumin the treatment of LUTS

Despite an unremitting increase in the number of patients presenting symptoms of benign prostate hyperplasia (BPH), the viable treatment options remain relatively limited when compared to other disorders of aging. This has spurred an interest in so-called alternative medicines, many of which continue to be used in spite of the more recent emergence of rationally targeted therapies. Nonetheless, in the case of plant extracts, the vast majority of these have not been subjected to the same rigorous pre-clinical pharmacological testing and large-scale clinical trials now required by health authorities. Furthermore, demonstration of their clinical efficacy in BPH has been hindered by trials of limited duration with a high placebo response. Beginning with a preliminary demonstration of in vitro inhibition of growth factor-mediated fibroblast proliferation with Pygeum africanum extract, a detailed series of in vitro and in vivo studies on prostate growth and bladder function were undertaken. These studies, reviewed herein, have permitted the identification of putative molecular targets of Pygeum africanum extract affecting both growth factor-mediated prostate growth as well as specific parameters of bladder function. These results, corroborated in part by short-term clinical efficacy, set the stage for a large-scale clinical trial to investigate the efficacy of Pygeum africanum extract in the treatment of lower urinary tract symptoms.

Pygeum africanum extract inhibits proliferation of human cultured prostatic fibroblasts and myofibroblasts

OBJECTIVE

To investigate the effect of Pygeum africanum (PA) extract on the proliferation of cultured human prostatic myofibroblasts and fibroblasts; this extract is used for treating urinary disorders associated with benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

Primary cultures of prostatic stromal cells were obtained from histologically confirmed human BPH by enzymatic digestion. Cell proliferation was measured by 5-bromo2'-deoxy-uridine (BrdU) incorporation assays, and cytotoxicity by luminescent quantification of adenylate kinase activity.

RESULTS

Cultured cells were labelled by an anti-vimentin antibody, and most of them by an alpha-smooth-muscle-actin antibody, revealing the presence of fibroblasts and myofibroblasts. BrdU incorporation tests showed that proliferation of cultured human stromal cells, stimulated by fetal calf serum, by basic fibroblast growth factor and by epidermal growth factor, was dose-dependently inhibited by PA extract (5-100 microg/mL). Except at 100 microg/mL, no acute cytotoxicity of the extract was detected after 24 h of culture. Similarly, the extract dose-dependently inhibited the proliferation of Madin-Darby canine kidney epithelial cells, but to a lesser extent; whatever the dose of extract, no acute toxicity was evident on this cell line.

CONCLUSION

PA extract inhibits the proliferation of cultured human prostatic myofibroblasts and fibroblasts. We propose that cultured human prostatic cells offer a reliable model for preclinical screening of therapeutic agents, and to study the mechanisms underlying the inhibition of proliferation.

Differentiated rabbit prostatic stromal cells in primary culture display functional α1A-adrenoceptors

AIMS

BPH is characterized by uncontrolled proliferation and increased contractility of prostatic smooth muscle cells. The activation of alpha1-adrenoceptors (alpha1-AR) seems involved in the latter event, but the lack of in vitro models expressing these receptors has hampered a more specific characterization of their role. In order to do so, we attempted to develop a new model of rabbit cultured prostatic stromal cells (PSC) in a non-proliferative and differentiated state.

METHODS

The expression of cytoskeletal and stromal markers was confirmed by immunohistochemistry on primary cultured PSC. Alpha1-AR subtype expression was assessed by RT-PCR, while receptor coupling to the ERK1/ERK2 and calcium pathways was studied by Western Blot and Fura-2 calcium imaging, respectively.

RESULTS

Cells grown under non-proliferative conditions displayed a differentiated phenotype, with expression of contractile cytoskeletal and stromal proteins. Furthermore, the alpha1A-AR was shown to activate ERK1/ERK2 as well as calcium signaling.

CONCLUSION

These results emphasize the interest of this model for the characterization of PSC adrenergic regulation, in particular through the little-known alpha1A-AR.

Low-dose tadenan protects the rabbit bladder from bilateral ischemia/ reperfusion-induced contractile dysfunction

Recent studies indicate that focal ischemia/reperfusion (I/R) can cause the contractile dysfunctions induced in animal models of partial bladder outlet obstruction. Tadenan (Pygeum africanum) pretreatment can prevent the rabbit bladder from developing the contractile and biochemical dysfunctions induced by partial outlet obstruction, possibly by protecting the bladder from ischemic injury. The current study was designed to determine whether pre-treating rabbits with a clinically relevant dose of Tadenan could prevent the bladder from developing the contractile dysfunctions that are induced by bilateral ischemia followed by reperfusion. New Zealand White rabbits were separated into two groups. One group was pre-treated by oral gavage for 3 weeks with Tadenan (3.0 mg/kg body wt./ day). The second group was treated with vehicle (peanut oil). Five rabbits from each group were subjected to either bilateral ischemia for 1 or 3 h and than reperfused for either 1 h or 1 week. Five rabbits from each group were subjected to sham surgery and run with each of the experimental groups. The results of the current study show that Tadenan pretreatment at the clinically relevant dose of 3.0 mg/kg body wt./day protected the bladder from the contractile dysfunctions induced by bilateral ischemia followed by reperfusion. These data are consistent with the assertion that Tadenan therapy in both rabbits and humans acts by protecting the bladder smooth muscle against cellular damage caused by ischemia and reperfusion.

Effect of Pygeum africanum tadenan on micturition and prostate growth of the rat secondary to coadministered treatment and post-treatment with dihydrotestosterone

OBJECTIVES

Pretreatment with oral tadenan (TAD) has been shown to possess a protective effect on bladder dysfunction-induced obstruction. We evaluated the functional influence of cotreatment and post-treatment with oral TAD on the frequency/volume characteristics of micturition of conscious rats stimulated with exogenous dihydrotestosterone (DHT) to induce experimental prostate growth.

METHODS

Studies were done on 36 adult Sprague-Dawley male rats, treated daily for 6 weeks and grouped as follows: group 1, sesame oil during weeks 1 and 2, peanut oil during weeks 3 to 6; group 2, DHT (1.25 mg/kg subcutaneously) dissolved in sesame oil as vehicle during weeks 1 and 2 and peanut oil during weeks 3 to 6; group 3, DHT (1.25 mg/kg subcutaneously) dissolved in sesame oil as vehicle and TAD (100 mg/kg orally) in peanut oil during weeks 1 and 2 and TAD during weeks 3 to 6; and group 4, DHT in sesame oil during weeks 1 and 2 and TAD in peanut oil during weeks 3 to 6. The characteristics of frequency/volume were monitored biweekly and at the sixth week.

RESULTS

Controls showed no significant changes from baseline values in volume or frequency during the entire study period. DHT treatment produced a significant increase in frequency (1.9 +/- 0.3 to 3.0 +/- 0.4/hr) and a significant decrease in volume (1.8 +/- 0.3 to 1.2 +/- 0.1 mL). In groups 3 and 4, no significant changes occurred in frequency or volume. By the sixth week of observation, the effects of DHT treatment decreased to control values in all groups. A significant increase in prostatic weight (1191 +/- 11 to 1434 +/- 17 mg/kg) was produced by DHT treatment and TAD cotreatment suppressed growth to 1390 +/- 8.4 mg/kg.

CONCLUSIONS

TAD cotreatment or post-treatment suppressed the effects of DHT on micturition, and TAD cotreatment regressed a developing increase in prostatic weight. Post-treatment TAD administration did not reduce already established growth.

Current concepts in the pharmacotherapy of benign prostatic hyperplasia

Benign prostatic hyperplasia is a major men's health issue, with approximately 80% of all men developing this condition within their lifetime. A variety of oral treatments is available, including alpha-adrenoceptor antagonists (alpha-blockers), 5alpha reductase inhibitors, aromatase inhibitors and phytotherapy. A large number of alpha-blockers can be administered, but no single agent has demonstrated a clear superiority over the other drugs. 5alpha Reductase inhibitors have demonstrated similar efficacy in larger volume prostates but most evidence suggests that there is no benefit in combining them with alpha-blockers. The use of phytotherapy is not entirely novel but requires further long-term evaluation before it can be endorsed for clinical use in benign prostatic hyperplasia.

Phytotherapy for benign prostatic hyperplasia

Phytotherapy has become a more popular treatment option among American men with benign prostatic hyperplasia (BPH). The most popular herbal agent is saw palmetto (Serenoa repens), which is derived from the berry of the American dwarf palm tree. Pygeum africanum and beta-sitosterol are also used by many patients with BPH, either alone or in combination with saw palmetto. A significant limiting factor to our understanding of the use and effectiveness of phytotherapy is the lack of standardization of these products. Despite this lack of standardization and the variation in results that may be seen with herbal products, there is growing evidence from well-conducted clinical trials that phytotherapeutic agents may lead to subjective and objective symptom improvement beyond a placebo effect in men with BPH. In addition, histologic evidence has been presented demonstrating that saw palmetto causes atrophy and epithelial contraction within the prostate gland. Overall, it is likely that herbal therapy will continue to be used by a growing number of Americans to treat a variety of ailments. Physicians should attempt to remain open-minded regarding alternative approaches and educate themselves so that they may counsel patients in an informed and credible fashion.

Herbal medications in the treatment of benign prostatic hyperplasia (BPH)

Herbal medications are used widely in the treatment of BPH. Recent studies suggest a benefit for some of these products with few side effects. The results of these studies are summarized and the possible mechanism of action of these medications are reviewed.

Effects of Pygeum africanum extract (Tadenan) on vasoactive intestinal peptide receptors, G proteins, and adenylyl cyclase in rat ventral prostate

BACKGROUND

Tadenan (a Pygeum africanum extract) is a drug used in the treatment of benign prostatic hyperplasia. Its effects on prostate fibroblast proliferation and bladder function after partial outlet obstruction have been demonstrated in various pharmacological studies. However, its effects at the molecular level are poorly documented.

METHODS

Tadenan was dissolved in peanut oil. Rats were orally given two daily doses of the drug (1 or 10 mg/kg b.w.) for 4 days. Vasoactive intestinal peptide (VIP) binding, adenylyl cyclase stimulation, and expression of G-protein subunits were studied in rat prostatic membranes by established procedures.

RESULTS

Tadenan treatment of castrated/testosterone-replaced rats was performed in order to interfere with prostatic cell proliferation. This experimental approach resulted in increases of: 1) VIP effect on adenylyl cyclase stimulation through alpha(s) G-subunit; 2) alpha(i) activation by low Gpp[NH]p doses (in the presence of forskolin); and 3) alpha(s), alpha(i1/2), and alpha(i3/0) levels. However, there were no modifications in membranes from quiescent, nonproliferating prostates (untreated rats).

CONCLUSIONS

The observed regulatory role of Tadenan on various prostatic components of the adenylyl cyclase system, together with previous findings on protein kinase C-mediated signal transduction, open a complex array of possibilities of direct actions of this phytotherapeutic agent in the prostate.

Defunctionalized bladders: effects before and after refunctionalization in an animal model

PURPOSE

Bladder behavior after refunctionalization is usually unpredictable. We comparatively analyze various aspects of bladder defunctionalization and subsequent refunctionalization using an animal model.

MATERIALS AND METHODS

A total of 18 rabbits were divided equally into 3 groups. Animals in group 1 underwent 2 successive surgical procedures, including bladder division and reattachment. Bladder division was performed by hemisecting the bladder from dome to trigone into a functioning and nonfunctioning chamber. Bladder reattachment was achieved by reanastomosing both hemibladders. Group 2 animals underwent sham operations, and group 3 animals were age matched normal controls. Serial urodynamic studies and fluoroscopic cystograms were performed in all animals. Gross, histochemical (hematoxylin and eosin, Masson's trichrome and Sirius red) and immunocytochemical (alpha-actin, collagen I and III) analyses, collagen content determination and organ bath studies were performed.

RESULTS

The defunctionalized hemibladders demonstrated lower wet weight, capacity and compliance compared to the functional contralateral and normal control bladders. Refunctionalization of the bladders resulted in a progressive recovery of capacity and compliance with time. The bladder contractile response and connective tissue-to-muscle ratio were abnormal in the defunctionalized segments but normalized after bladder refunctionalization.

CONCLUSIONS

Defunctionalization results in remarkable alterations in bladder growth, capacity, compliance and distribution of connective tissue. However, these bladders demonstrate an innate capacity to recover from these alterations following refunctionalization.

Phytotherapeutic agents in the treatment of benign prostatic hyperplasia

The rationale and efficacy of phytotherapeutic agents in the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH) are continuously debated. While plant extracts are prescribed and reimbursable treatment options in Europe, they are officially classified merely as dietary supplements in the United States. The most commonly used preparations originate from the species Serenoa repens, Pygeum africanum, hypoxis rooperi, pinus, picea, urtica dioica, and secale cereale. Combination extracts derived from two or more plants are also used. Various components have been suggested to be active, and different mechanisms of action are being supposed. Open trials and some short-term randomized studies, suggesting safety and efficacy, have been reported. However, if stringent criteria of evidence-based medicine are applied, the data are inconclusive. Therefore, the 4th International Consultation on BPH and the recent German guidelines have not (yet) recommended phytotherapy for the management of symptomatic BPH.

Phytotherapy for chronic prostatitis

Chronic prostatitis is a poorly defined condition that is difficult to treat; there are therefore multiple therapies. Although there is a paucity of trials using phytotherapeutic agents, plant extracts have been postulated to have anti-inflammatory effects that might be useful in the treatment of chronic prostatitis. More placebo-controlled trials of longer duration in this condition are needed to ascertain whether there is a significant benefit to the use of phytotherapeutic agents for chronic prostatitis.

Functional evaluation of Tadenan on micturition and experimental prostate growth induced with exogenous dihydrotestosterone

OBJECTIVES

To evaluate the effect of Tadenan (TAD; Pygeum africanum extract) pretreatment on the micturition characteristics of conscious and anesthetized rats consequent to dihydrotestosterone (DHT) administration and to examine the influence of such treatment on the growth of the prostate.

METHODS

Studies using 40 adult Sprague-Dawley male rats were performed during a 7-week period. These animals were treated with DHT 1.25 mg/kg subcutaneously dissolved in peanut oil and/or TAD 100 mg/kg orally dissolved in sesame oil, except for the controls, which received vehicle only. Rats were divided into four groups: group 1 (control), vehicle only; group 2, DHT administered during weeks 3 and 4; group 3, TAD pretreatment, administered during weeks 1 and 2, followed by the combined administration of DHT and TAD during weeks 3 and 4 and TAD only during weeks 5 to 7; and group 4, continuous TAD treatment for 7 weeks. Micturition of conscious rats was evaluated in metabolic chambers, and in anesthetized rats, cystometrograms were done at the end of 7 weeks.

RESULTS

DHT or DHT plus TAD did not produce significant changes in the volume but did reduce the frequency of micturition. TAD given alone significantly increased the volume of micturition and the rate of urine production. Cystometrographic studies in anesthetized rats revealed that DHT produced micturition characteristics similar to obstruction. The DHT plus TAD and TAD pretreatment data showed no significant difference from controls, suggesting that in the presence of TAD, the effects of DHT were negated. The total prostate weight of DHT and DHT plus TAD pretreated rats increased, and in the TAD group, these values decreased to lower than controls; growth of the ventral lobes was suppressed in the presence of TAD.

CONCLUSIONS

These results demonstrate that TAD pretreatment significantly reduces the "obstructive" effects of DHT on micturition, counteracts the hormone-induced enlargement of the prostate, and reduces prostate weight in the ventral but not the dorsal lobe.

Identification of components of Prunus africana extract that inhibit lipid peroxidation

Extractive and chromatographic separations were performed on V-1326, a chloroform extract from the bark of Prunus africana (also referred to as Pygeum africanum), which is used to treat the symptoms associated with benign prostate hyperplasia (BPH). The relative amounts of eleven identified constituents in crude V-1326 and in separated fractions were determined using gas chromatographic analysis. The ability of V-1326 and its separated fractions to inhibit ferrous ion-induced stimulation of lipid peroxidation in microsomal preparations from rabbit livers was evaluated. The extract, V-1326, and fractions containing high levels of myristic acid potently inhibited lipid peroxidation.

Sucrose diuresis protects rat bladder from outlet partial obstruction-induced contractile dysfunction

OBJECTIVES

Evidence is accumulating that bladder dysfunction caused by experimental partial obstruction of the bladder outlet can be reduced or reversed by treatment that results in upregulation of bladder function, even in the presence of obstruction. Inducing diuresis in rats or rabbits results in a significant increase in bladder mass and increased contractility in response to stimulation. The objective of the present study was to determine whether diuresis-induced amplification of bladder function in the rat could protect the bladder from contractile dysfunctions caused by partial outlet obstruction.

METHODS

Thirty-two rats were separated into four groups of 8 rats each. Groups 2 and 4 were fed 5% sucrose instead of water; groups 1 and 3 were fed only water. Three weeks later, partial outlet obstructions were created in groups 3 and 4. After 4 weeks of obstruction, all bladders were rapidly excised and cut into longitudinal strips; each strip was mounted in an isolated muscle bath for contractile studies.

RESULTS

Sucrose-induced diuresis caused a moderate but significant increase in bladder mass. Partial outlet obstruction stimulated significant increases in bladder mass in both water-drinking and sucrose-drinking groups; the bladder mass of sucrose-drinking rats, however, increased less than that of water-drinking rats. In water-drinking rats, partial outlet obstruction resulted in significantly decreased bladder strip contractility in vitro in response to field stimulation (1 to 32 Hz), carbachol (0.1 to 22 microM), and KCl (120 mM). After 3 weeks of sucrose-induced diuresis, partial obstruction of the rat bladder outlet did not result in decreased in vitro contractile responses to any form of stimulation applied.

CONCLUSIONS

Sucrose-induced diuresis caused an increase in bladder mass and an increase in contractile strength, consequently protecting the rat bladder from the contractile dysfunctions that usually follow partial outlet obstruction.

Review of recent placebo-controlled trials utilizing phytotherapeutic agents for treatment of BPH

BACKGROUND

In order to assess the efficacy of phytotherapeutic agents for the treatment of benign prostatic hyperplasia (BPH), a review of recently published double-blind placebo-controlled trials was undertaken.

METHODS

Only those studies reviewed by the Other Medical Therapies Committee of the Fourth International Consultation on BPH were included.

RESULTS

These studies suggest a possible benefit for the use of phytotherapeutic preparations in the treatment of BPH.

CONCLUSIONS

These studies need to be confirmed in larger long-term placebo-controlled studies in order to ascertain the true efficacy of these agents.

Effects of polyamine synthesis inhibition on polyamines, growth and mechanical properties in hypertrophic rat urinary bladder

The polyamines putrescine, spermidine and spermine, are ubiquitous intracellular metabolites associated with growth and protein synthesis. In this study effects of polyamine synthesis inhibition on bladder growth, polyamine levels and mechanical properties were investigated in rat urinary bladder subjected to partial outflow obstruction that causes bladder hypertrophy. The S-adenosyl methionine decarboxylase inhibitor CGP-48664 (5 and 20 mg kg-1) was administered alone or in combination with the ornithine decarboxylase inhibitor DFMO (500 mg kg-1), starting one day before creation of partial outflow obstruction and then daily for 7 days. The bladder muscle level of putrescine was increased 38 times and that of spermine reduced by 4 times while spermidine was unchanged after treatment with CGP-48664 (20 mg kg-1). The increase in putrescine was abolished in animals receiving CGP-48664 in combination with DFMO. Treatment with polyamine synthesis inhibitors could not prevent or reduce the hypertrophy of the bladder as judged by bladder wet weight and protein contents. The effects on polyamine quantities were not associated with changes in Ca(2+)-force relationship or in agonist and electrically stimulated force. In summary, treatment of rats with polyamine synthesis inhibitors resulted in changes in polyamine levels in the growing urinary bladder but did not affect growth or mechanical properties.

Phytotherapy in the treatment of benign prostatic hyperplasia

There are numerous plant extracts that have been used for the treatment of benign prostatic hyperplasia and voiding dysfunction. While some extracts show promise, their efficacy has not been adequately proven in long-term, double-blind, placebo-controlled trials. In addition, the mechanism of action remains poorly defined.

Phytotherapy in treatment of benign prostatic hyperplasia: a critical review

Phytotherapeutic agents have enjoyed widespread use, especially in Europe, for the treatment of BPH. With the recent proliferation of nutrition and vitamin stores in the United States, use of these agents has greatly increased. Although SPB extract is the most extensively studied of the phytotherapeutic agents used for BPH, no well-defined mechanism of action has been proposed. Evidence for an antiandrogenic or antiestrogenic effect is conflicting, and there are no clinical data suggesting an effect on 5-alpha-reductase activity. Furthermore, clinical trials with SPB have largely been uncontrolled and are thus of limited value in ascertaining the true clinical impact of this agent. Double-blind, controlled studies with SPB also have limitations in that most were of very short duration (none longer than 3 months) and did not provide entry or exclusion criteria. In addition, standardized symptom scores were not utilized. Only two of seven studies showed an appropriate placebo response, and the results and conclusions of both these studies were contradictory. The best and most convincing study of the efficacy of phytotherapeutic agents (using Harzol) was recently published in the Lancet. This study was rigorous and matched in design and format with pharmaceutical industry trials. A mild but appropriate placebo response was detected, which further validates the study. However, a prior placebo-controlled study showed no efficacy of beta-sitosterol-beta-D-glucoside. This dichotomy of results possibly reflects the different composition of the agents tested. This is a major confounding factor in this field of study, especially because the active ingredients are unknown. Standardization of the compounds is needed to compare and assess accurately the effect of the different extracts.