Medical management of lower urinary tract symptoms in men: current treatment and future approaches

Future aspects of plant derived bioactive metabolites as therapeutics to combat benign prostatic hyperplasia

ETHNOPHARMACOLOGICAL RELEVANCE

Benign prostatic hyperplasia (BPH), characterized by prostate enlargement due to cell proliferation, is a common urinary disorder in men over 50, manifesting as lower urinary tract symptoms (LUTS). Currently, several therapeutic options are accessible for treating BPH, including medication therapy, surgery and watchful waiting. Conventional drugs such as finasteride and dutasteride are used as 5α-reductase inhibitors for the treatment of BPH. However long-term use of these drugs is restricted due to their unpleasant side effects. Despite the range of available medical therapies, the effective treatment against BPH is still inadequate. Certain therapeutic plants and their phytochemicals have the aforementioned goals and work by regulating this enzyme.

AIM OF THE STUDY

This review aims to provide a comprehensive insight to advancements in diagnosis of BPH, modern treatment methods and the significance of ethnobotanically relevant medicinal plants as alternative therapeutics for managing BPH.

MATERIAL AND METHODS

A thorough and systematic literature search was performed using electronic databases and search engines such as PubMed, Web of Science, NCBI and SciFinder till October 2023. Specific keywords such as "benign prostatic hyperplasia", "medicinal plants", "phytochemicals", "pharmacology", "synergy", "ethnobotany", "5-alpha reductase", "alpha blocker" and "toxicology". By include these keywords, a thorough investigation of pertinent papers was assured, and important data about the many facets of BPH could be retrieved.

RESULTS

After conducting the above investigation, 104 herbal remedies were found to inhibit Phosphodiesterase-5 (PDE-5) inhibition, alpha-blockers, or 5α -reductase inhibition effects which are supported by in vitro, in vivo and clinical trial studies evidence. Of these, 89 plants have ethnobotanical significance as alpha-blockers, alpha-reductase inhibition, or PDE-5 inhibition, and the other fifteen plants were chosen based on their ability to reduce BPH risk factors. Several phytocompounds, including, rutaecarpine, vaccarin, rutin, kaempferol, β-sitosterol, quercetin, dicaffeoylquinic acid, rutaevin, and phytosterol-F have been reported to be useful for the management of BPH. The use of combination therapy offers a strong approach to treating long-term conditions compare to single plant extract drugs. Furthermore, several botanical combinations such as lycopene and curcumin, pumpkin seed oil and saw palmetto oil, combinations of extracts from Funtumia africana (Benth.) Stapf and Abutilon mauritianum (Jacq.) Medik., and Hypselodelphys poggeana (K.Schum.) Milne-Redh. and Spermacoce radiata (DC.) Sieber ex Hiern are also supported through in vitro and in vivo studies for managing BPH through recuperation in patients with chronic long-term illnesses, as measured by the International Prostate Symptom Score.

CONCLUSION

The review proposes and endorses careful utilization of conventional medications that may be investigated further to discover possible PDE-5, 5 alpha-reductase, an alpha-blocker inhibitor for managing BPH. Even though most conventional formulations, such as 5 alpha-reductase, are readily available, systemic assessment of the effectiveness and mechanism of action of the herbal constituents is still necessary to identify novel chemical moieties that can be further developed for maximum efficacy. However, there exist abundant botanicals and medicinal plants across several regions of Africa, Asia, and the Americas, which can be further studied and developed for utilization as a potential phytotherapeutic for the management of BPH.

Inhibition of Human Prostate and Bladder Smooth Muscle Contraction, Vasoconstriction of Porcine Renal and Coronary Arteries, and Growth-Related Functions of Prostate Stromal Cells by Presumed Small Molecule Gαq/11 Inhibitor, YM-254890

Introduction: Lower urinary tract symptoms (LUTS) involve benign prostatic hyperplasia (BPH) and overactive bladder (OAB). Standard-of-care medical treatment includes α1-blockers and antimuscarinics for reduction of prostate and detrusor smooth muscle tone, respectively, and 5α-reductase inhibitors (5-ARI) to prevent prostate growth. Current medications are marked by high discontinuation rates due to unfavourable balance between efficacy and treatment-limiting side effects, ranging from dry mouth for antimuscarinics to cardiovascular dysregulation and a tendency to fall for α1-blockers, which results from hypotension, due to vasorelaxation. Agonist-induced smooth muscle contractions are caused by activation of receptor-coupled G-proteins. However, little is known about receptor- and organ-specific differences in coupling to G-proteins. With YM-254890, a small molecule inhibitor with presumed specificity for Gαq/11 became recently available. Here, we investigated effects of YM-254890 on prostate, bladder and vascular smooth muscle contraction, and on growth-related functions in prostate stromal cells.

Methods: Contractions of human prostate and detrusor tissues, porcine renal and coronary arteries were induced in an organ bath. Proliferation (EdU assay), growth (colony formation), apoptosis and cell death (flow cytometry), viability (CCK-8) and actin organization (phalloidin staining) were studied in cultured human prostate stromal cells (WPMY-1).

Results: Contractions by α1-adrenergic agonists, U46619, endothelin-1, and neurogenic contractions were nearly completely inhibited by YM-254890 (30 nM) in prostate tissues. Contractions by cholinergic agonists, U46619, endothelin-1, and neurogenic contractions were only partly inhibited in detrusor tissues. Contractions by α1-adrenergic agonists, U46619, endothelin-1, and neurogenic contractions were strongly, but not fully inhibited in renal arteries. Contractions by cholinergic agonists were completely, but by U46619 and endothelin-1 only strongly inhibited, and neurogenic contractions reduced by half in coronary arteries. YM-254890 had no effect on agonist-independent contractions induced by highmolar (80 mM) potassium chloride (KCl). Neurogenic detrusor contractions were fully sensitive to tetrodotoxin. In WPMY-1 cells, YM-254890 caused breakdown of actin polymerization and organization, and obvious, but clearly limited decreases of proliferation rate, colony formation and viability, and slightly increased apoptosis.

Conclusion: Intracellular post-receptor signaling pathways are shared by Gαq-coupled contractile receptors in multiple smooth muscle-rich organs, but to different extent. While inhibition of Gαq/11 causes actin breakdown, anti-proliferative effects were detectable but clearly limited. Together this may aid in developing future pharmaceutical targets for LUTS and antihypertensive medication.

Amelioration of testosterone-induced benign prostatic hyperplasia using febuxostat in rats: The role of VEGF/TGFβ and iNOS/COX-2

Benign prostatic hyperplasia (BPH) is a common male disorder. Febuxostat is a non-purine, selective inhibitor of xanthine oxidase (XO), which has a strong antioxidant capacity and pleiotropic pharmacological properties. This study's objective was to explore the potential ameliorative effects of febuxostat against testosterone-induced BPH in rats. Febuxostat (10 mg/kg/day, per os [p.o.]) prevented increased prostate index levels, serum levels of prostate-specific antigen (PSA), and testosterone levels compared to animals treated with testosterone alone, when administered for 28 days. Histological examination indicated that febuxostat dramatically ameliorated pathological changes in the prostate architecture compared to the testosterone group. Similarly, febuxostat markedly improved testosterone-induced oxidative stress by inhibiting the increase in lipid peroxide and nitrite content, and by reducing the level of depletion of reduced glutathione (GSH) and superoxide dismutase (SOD) activity, which significantly reduced the prostate content of pro-inflammatory cytokines, including tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6). Furthermore, febuxostat significantly reduced the prostatic content, both in terms of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) messenger ribonucleic acid (mRNA) levels, and of protein levels. Moreover, compared to the testosterone group, febuxostat's beneficial effects prevented the increase in growth factors, comprising vascular endothelial cell growth factor A (VEGF-A) and transforming growth factor beta (TGF-β) protein levels. Its ameliorating effects were equal to those of finasteride, which is the most widely used remedy for BPH. In conclusion, this study provides novel evidence that febuxostat experimentally attenuates testosterone-induced BPH in rats, at least in part by inhibiting iNOS/COX-2 and VEGF/TGF-β pathways.

The Effect of Xialiqi Capsule on Testosterone-Induced Benign Prostatic Hyperplasia in Rats

Benign prostatic hyperplasia (BPH) is common among elderly men, of which inflammation, oxidative stress, proliferative, and apoptotic changes play important roles. Xialiqi (XLQ) capsule, a traditional Chinese herbal formula, is used as a potential drug in treating BPH. This study aims to evaluate the therapeutic effect of XLQ capsule on testosterone propionate- (TP-) induced BPH in rats. Fifty male Sprague-Dawley rats were randomly divided into 5 groups: sham control, BPH model, high and low dose of XLQ, and finasteride as a positive control group. All groups were treated with appropriate drugs/normal saline for 28 consecutive days. Prostate weights were recorded; histopathological changes and content of IL-8, TNF-α, DHT, SOD, MDA, caspase-3, and PCNA of the prostate were determined. Animals with BPH demonstrated significantly increased prostate weights and prostate index, higher levels of IL-8, TNF-α, DHT, MDA, and PCNA, but lower activity of SOD and reduced expression of caspase-3. After treatment with XLQ, significant reductions of prostate weights, prostate index, IL-8, TNF-α, DHT, MDA, and PCNA, increased activity of SOD, and higher level of caspase-3 were shown. The present study indicates that XLQ can effectively prevent the development of TP-induced BPH model through mechanisms of anti-inflammation, antioxidation, antiproliferation, and proapoptosis.

Inhibitory effect of curcumin on testosterone induced benign prostatic hyperplasia rat model

Background

Benign prostatic hyperplasia (BPH) is one of the common male diseases, which is provoked by dihydrotestosterone (DHT) and androgen signals. Several studies showed that curcumin has various effects of prevention and treatment to diseases. We investigated whether curcumin may repress the development of BPH in male Wistar rats.

Methods

Seven weeks male Wistar rats were and divided into 4 groups (normal group, BPH group, finasteride group, curcumin group; n = 8 for each group). In order to induce BPH in rats, rats were castrated and testosterone was injected subcutaneously everyday (s.c., 20 mg/kg). Rats in the curcumin group were treated 50 mg/kg, administered orally for 4 weeks. After 4 weeks, all rats were sacrificed and their prostate and serum were analyzed.

Results

Compared to the finasteride group as positive group, the curcumin group showed similarly protective effect on BPH in histopathologic morphology, prostate volume. Results of immunohistochemistry and western-blot showed decreased expressions of VEGF, TGF-ß1, and IGF1 were also decreased in the curcumin group.

Conclusions

These results suggested that curcumin inhibited the development of BPH and might a useful herbal treatment or functional food for BPH.

Influence of Panax ginseng on Alpha-Adrenergic Receptor of Benign Prostatic Hyperplasia

Purpose

Benign prostatic hyperplasia (BPH) is the most common prostate problem in older men. The present study aimed to investigate the inhibitory effect of Panax ginseng C.A. Meyer (P. ginseng) on a rat model of testosterone-induced BPH.

Methods

The rats were divided into 3 groups (each group, n=10): control, testosterone-induced BPH (20 mg/kg, subcutaneous injection), and P. ginseng (200 mg/kg, orally) groups. After 4 weeks, all animals were sacrificed to examine the blood biochemical profiles, prostate volume, weight, histopathological changes, alpha-1D adrenergic receptor (Adra1d) mRNA expression, and epidermal growth factor receptor (EGFR) and B-cell CLL/lymphoma 2 (BCL2) protein expression.

Results

The group treated with P. ginseng showed significantly lesser prostate size and weight than the testosterone-induced BPH group. In addition, P. ginseng decreased the mRNA expression of Adra1d as well as the expression of EGFR and BCL2 in prostate tissue.

Conclusions

These results suggest that P. ginseng may inhibit the alpha-1-adrenergic receptor to suppress the development of BPH.

Is There a Relation between Reticular Formation and Storage Symptoms in Men

OBJECTIVE

To reveal brainstem originated pathology in men with different types of lower urinary tract symptoms blink reflex latency times were assessed.

METHODS

A total of 32 men, 16 with storage and 16 with voiding symptoms, were enrolled in the study. Blink reflex latency times were analyzed through electrical stimulation of the supraorbital nerve. Two responses in the orbicularis oculi muscle were recorded: the latency times for the early ipsilateral response, R1, and the late bilateral responses, R2.

RESULTS

The mean ages of the patients with storage and voiding symptoms were 57.31 ± 6.87 and 58.06 ± 6.29 years, respectively. The R2 latency times were significantly longer in men with storage symptoms. However, the R1 latency times were similar for the two groups.

CONCLUSION

Late blink latency times were long only in patients who had storage symptoms. An oligosynaptic path through the trigeminal nuclei, which includes one or two interneurons, is responsible for early response; however, late response is relayed through a polysynaptic path, including neurons in the reticular formation. It has also been shown that stimulation of the pontine reticular formation inhibits the micturition contraction. In some patients, storage symptoms may result from pathology that originates with the reticular formation and this pathology may lead to increases in late blink latency times. Additional studies are needed on other reflexes that are mediated through reticular formation, in order to show the possible dysfunction of the reticular formation in men with storage symptoms.

Add-on fesoterodine for residual storage symptoms suggestive of overactive bladder in men receiving α-blocker treatment for lower urinary tract symptoms

Study Type - Therapy (RCT) Level of Evidence 1b What's known on the subject? and What does the study add? Male lower urinary tract symptoms are often attributed to bladder outlet obstruction secondary to benign prostatic hyperplasia and treated with drugs targeting the prostate. However, many men with storage lower urinary tract symptoms may not respond adequately to these agents. Antimuscarinics, with or without an α-blocker, may be effective for the treatment of the storage symptoms of overactive bladder in some men. Flexible-dose fesoterodine as an add-on treatment significantly improved urinary frequency and symptom bother, but not urgency episodes (primary endpoint), versus add-on placebo and was well tolerated in men with persistent overactive bladder symptoms despite receiving α-blocker.

OBJECTIVE

• To evaluate flexible-dose fesoterodine vs placebo in men with persistent overactive bladder (OAB) symptoms despite receiving α-blocker treatment

SUBJECTS AND METHODS

• This was a double-blind, 12-week, flexible-dose trial. • Men with persistent storage symptoms (≥ 8 micturitions and ≥ 3 urgency episodes per 24 h) after receiving an α-blocker for ≥ 6 weeks were randomized to add-on fesoterodine 4 mg or placebo, with optional dose escalation to 8 mg at week 4 and reduction back to 4 mg at week 8 (or matching placebo adjustments). • Subjects completed 3-day diaries, International Prostate Symptom Score (IPSS), Overactive Bladder Questionnaire (OAB-q), Patient Perception of Bladder Condition (PPBC), and Urgency Perception Scale (UPS) at baseline and weeks 4 and 12.

RESULTS

• A total of 943 men were randomized and received at least one dose of study treatment (fesoterodine, n= 471; placebo, n= 472). • Among these, 251 (53%) in the fesoterodine group and 300 (64%) in the placebo group requested dose escalation at week 4 and 35 (7%) and 15 (3%) requested dose reduction at week 8. Changes from baseline to week 12 in urgency episodes (primary endpoint) in the fesoterodine (-3.2) and placebo (-2.9) groups were not significantly different (P= 0.196), but improvements in micturitions (P= 0.009) and OAB-q symptom bother score (P= 0.007) were significantly greater with fesoterodine. • At week 4, significantly greater improvements in micturitions (P= 0.006), severe urgency episodes (P= 0.006), IPSS storage score (P= 0.022), OAB-q symptom bother score (P= 0.004), and OAB-q health-related quality of life (P= 0.041), but not urgency episodes (P= 0.062), were observed with add-on fesoterodine. • Dry mouth (fesoterodine, 21%; placebo, 6%) and constipation (fesoterodine, 6%; placebo, 2%) were the most common adverse events. Dysuria and urinary retention were reported by 3% and 2% of subjects, respectively, in the fesoterodine add-on group vs 1% and <1% of subjects, respectively in the placebo add-on group. One subject in each group had acute urinary retention requiring catheterization.

CONCLUSIONS

• Flexible-dose fesoterodine was well tolerated as an add-on treatment in men with persistent storage symptoms. • Changes in urgency episodes at week 12 (primary endpoint) and many secondary endpoints were not significantly different between fesoterodine and placebo add-on treatment; however, improvements in frequency and symptom bother were significantly greater with fesoterodine. • These data suggest that there remains a limited understanding of the optimal evaluation and treatment of men with LUTS.

Human prostatic urethra expresses vitamin D receptor and responds to vitamin D receptor ligation

BACKGROUND

Chronic inflammation is now considered a determinant of benign prostatic hyperplasia (BPH), promoting, together with the hormonal milieu, prostate overgrowth and lower urinary tract symptoms (LUTS). Prostatic urethra actively participates in determining progression of LUTS associated with BPH.

AIM

To investigate the expression of the vitamin D receptor (VDR) and the ability of the VDR agonist elocalcitol to reduce inflammatory responses in human prostatic urethra (hPU) cells.

MATERIALS AND METHODS

Human prostatic urethra, prostate and bladder neck were obtained from patients affected by BPH. Immunohistochemical studies for VDR expression were performed in tissue samples, from which primary cell cultures were also derived. In hPU cells, proliferation and chemiotaxis were studied, along with Rho kinase (ROCK) activity (MYPT-1 phosphorylation) by western blot. Quantitative RT-PCR was performed for VDR, cyclooxygenase (COX-2), and interleukin (IL)-8 expression.

RESULTS

Urethra displays higher VDR expression compared to prostate and bladder neck tissues. The VDR agonist elocalcitol partially reverts COX-2 and IL-8 mRNA upregulation induced by a pro-inflammatory cytokine mixture (IL-17, interferon-γ, tumor necrosis factor-α) and inhibits cell migration in urethral cells. Elocalcitol prevents activation of ROCK, as previously demonstrated in bladder and prostate cell cultures.

CONCLUSIONS

Our results suggest that prostatic urethra is, within the lower urinary tract, a novel target for VDR agonists, as shown by the capacity of elocalcitol to inhibit ROCK activity and to limit inflammatory responses in human primary urethra cells.

Long-term outcome of patients with a successful trial without catheter, after treatment with an alpha-adrenergic receptor blocker for acute urinary retention caused by benign prostatic hyperplasia

OBJECTIVE

To perform a retrospective review of long-term outcome for patients with a first episode of acute urinary retention (AUR) who could void successfully after the initial trial without catheter (TWOC) after treatment with an alpha-adrenergic receptor blocker (AR blocker).

METHODS

The records of 248 patients who presented with a first episode of AUR secondary to benign prostatic hyperplasia (BPH) and who could void successfully after the initial TWOC following treatment with an AR blocker were reviewed during the period January 1998 to December 2001. The characteristics of the patients and the subsequent outcomes were recorded. The primary outcome assessed was failed medical treatment within the five-year follow-up period. Factors correlated with the primary outcome were also assessed.

RESULTS

For these 248 patients, the median follow-up time was 33.0 months (range 0-96 months). The percentage of patients with failed medical treatment at 6, 12, 24, and 60 months was 11.6, 14.3, 28.4, and 50.5%, respectively. Multivariate analysis indicated that only a prostate size >50 ml and serum prostate specific antigen (PSA) level during AUR >10 ng/dl were significant predictors of subsequent requirement for surgical intervention after a successful TWOC.

CONCLUSIONS

Although AR blockers increased the success rate of TWOC, approximately half of the patients in this study still required additional intervention within five years. By using appropriate selection criteria, such as a large prostate size (>50 ml) or high serum PSA level during AUR (>10 microg/l), patients who are at greater risk of TWOC failure can be identified, and earlier surgical intervention can be offered to them.