A new experimental rat model of erectile dysfunction and lower urinary tract symptoms associated with benign prostatic hyperplasia: the testosterone-supplemented spontaneously hypertensive rat

Analysis of salivary flow rate, biochemical composition, and redox status in orchiectomized spontaneously hypertensive rats

OBJECTIVE

This study aimed to analyze the salivary flow rate, biochemical composition, and redox status in orchiectomized spontaneously hypertensive rats (SHR) compared to normotensive Wistar rats.

DESIGN

Thirty-two young adult male SHR and Wistar (3-months-old) rats were randomly distributed into four groups; either castrated bilaterally (ORX) or underwent fictitious surgery (SHAM) as Wistar-SHAM, Wistar-ORX, SHR-SHAM, and SHR-ORX. Two months beyond castration, pilocarpine-induced salivary secretion was collected from 5-month-old rats to analyze salivary flow rate, pH, buffer capacity, total protein, amylase, calcium, phosphate, sodium, potassium, chloride, thiobarbituric acid reactive substances (TBARs), carbonyl protein, nitrite, and total antioxidant capacity.

RESULTS

The salivary flow rate was higher in the Wistar-ORX compared to the Wistar-SHAM group, while remaining similar between the SHR-SHAM and SHR-ORX groups. ORX did not affect pH and salivary buffer capacity in both strains. However, salivary total protein and amylase were significantly reduced in the Wistar-ORX and SHR-ORX compared to the respective SHAM groups. In both ORX groups, salivary total antioxidant capacity and carbonylated protein were increased, while lipid oxidative damage (TBARs) and nitrite concentration were higher only in the Wistar-ORX than in the Wistar-SHAM group. In the Wistar-ORX and SHR-ORX, the salivary calcium, phosphate, and chloride were increased while no change was detected in the SHAM groups. Only salivary buffering capacity, calcium, and chloride in the SHR-ORX adjusted to values similar to Wistar-SHAM group.

CONCLUSION

Hypertensive phenotype mitigated the orchiectomy-induced salivary dysfunction, since the disturbances were restricted to alterations in the salivary biochemical composition and redox state.

An inhibitory effect of Berberine from herbal Coptis chinensis Franch on rat detrusor contraction in benign prostatic hyperplasia associated with lower urinary tract symptoms

ETHNOPHARMACOLOGICAL RELEVANCE

Coptis chinensis Franch (CCF), also known as Huang Lian in China, is a traditional Chinese medicine that commonly used for more than 2000 years. Clinically, CCF often used as anti-inflammatory, immune regulation and other effects. It has been reported that the decoction containing CCF can be used for the treatment of benign prostatic hyperplasia (BPH) or lower urinary tract symptoms (LUTS).

AIM OF THE STUDY

This research aims to investigate the effect of CCF on inhibition of BPH development in vivo and in vitro, and further identify the active compound (s) and the possible mechanism involved in BPH-related bladder dysfunction.

MATERIALS AND METHODS

Oestrodial/testosterone-induced BPH rat model was established as the in vivo model. The prostate index (PI) was calculated, the pathogenesis was analyzed and the micturition parameters were determined in the shamed-operated, BPH model and BPH + CCF groups after 4-week administration. The tension in detrusor strips was then assessed upon KCl or ACh stimulation with or without incubation of CCF or active compounds. To further investigate the signaling involved, rat detrusor cells were cultured as the in vitro models, the instantaneous calcium influx was measured and the ROCK-1 expression was detected.

RESULTS

Increased PI value and the aggravated prostatic pathology were observed with voiding dysfunction in BPH rats, which were significantly blocked by oral CCF taken. ACh or KCl-induced contractile responses in detrusor strips were significantly inhibited and the micturition parameters were improved when incubation with CCF or its active compounds such as berberine. Both CCF and berberine suppressed the cellular calcium influx and ROCK-1 expression upon ACh stimulation, demonstrating that berberine was one of the active compounds that contributed to CCF-improved micturition symptoms and function.

CONCLUSIONS

Taken together, our findings give evidence that CCF and its active compound berberine inhibited BPH and bladder dysfunction via Ca²⁺ and ROCK signaling, supporting their clinical use for BPH and BPH-related LUTS treatment.

Effects of the dutasteride and sildenafil association in the penis of a benign prostatic hyperplasia animal model

OBJECTIVE

The aim of this study was to investigate whether concomitant treatment of dutasteride and sildenafil could prevent structural changes in the penis of a BPH rodent model.

METHODS

Thirty-two adult male rats were divided into the following groups: Ctrl, untreated control rats; BPH, untreated spontaneously hypertensive rats (SHRs); BPH + D, SHRs treated with dutasteride; and BPH + DS, SHRs treated with dutasteride and sildenafil. All treatments were performed during 40 days, following which the penises were collected for histomorphometrical analysis. The results were compared via one-way ANOVA with Bonferroni's post-test, considering p values <.05 as significant.

RESULTS

The smooth muscle density decreased by 28.6% and 21.4% in BPH + D and BPH + DS, respectively, when compared to the BPH group. The sinusoid space density reduced by 32.2% in BPH, when compared to the Ctrl group; this density was also reduced by 22.6% in BPH + D, when compared to the BPH group. The density of the elastic fibers increased 51.6% and 65.6% in BPH + D and BPH + DS, when compared to the BPH group.

CONCLUSION

Treatment with dutasteride promoted morphological changes in the corpus cavernous of this BPH model. Concomitant treatment with sildenafil did not prevent the morphological changes caused by dutasteride; on the contrary, it also promoted a further increase in elastic fibers.

Silodosin improves functional consequences of lower urinary tract obstruction secondary to benign prostate hypertrophy, a proof of concept study in the spontaneously hypertensive rat supplemented with testosterone

Background

The main purpose of this study is to investigate the effect of silodosin on the urodynamic consequences in a previously established model of lower urinary tract symptoms associated with benign prostate hyperplasia, the spontaneously hypertensive rats (SHR) supplemented with testosterone.

Methods

Three groups of animals (8-week-old; n = 10/group) were considered: Wistar Kyoto (control) rats (WKY), SHR supplemented with testosterone at 3 mg/kg/day and treated with either vehicle (SHR-T, n = 10) or silodosin at 0.1 mg/kg/day (SHR-T + silodosin, n = 10) by oral gavage for 6 weeks. Cystometry experiments were performed. The bladder was harvested, weighed and paraffin-embedded for morphometric analysis. The prostate was also harvested and weighed.

Results

The number of animals included in the analysis were n = 10/10 for WKY and n = 7–8/10 for each SHR rats supplemented with testosterone group. SHR-T displayed a significant decrease in the intercontraction interval, infused volume and mean flow rate whereas the frequency of non-voiding contractions was increased. Silodosin improved the voiding behavior of SHR-T by significantly increasing the intercontraction interval, the infused volume and the mean flow rate and decreasing the number of non-voiding contractions. SHR-T displayed a significant increase in prostate and bladder weights and a 15% increase in the detrusor wall area compared to WKY.

Conclusions

Chronic silodosin treatment relieved storage symptoms in SHR supplemented with testosterone and decreased the frequency of non-voiding detrusor contractions during the filling phase.

Extracorporeal Shock Waves Therapy Delivered by Aries Improves Erectile Dysfunction in Spontaneously Hypertensive Rats Through Penile Tissue Remodeling and Neovascularization

Background

Low-intensity extracorporeal shock wave therapy (Li-ESWT) has been reported to improve erectile function in patients with moderate-to-severe erectile dysfunction (ED) or even convert phosphodiesterase type 5 inhibitors nonresponders to responders. ED is highly prevalent in hypertensive patients. The effect of Li-ESWT on an animal model of hypertension-associated ED has not been reported.

Aim

To investigate the effect of Li-ESWT on hypertension-associated ED and provide plausible mechanisms of action of Li-ESWT on local mechanisms of penile erection.

Methods

Spontaneously hypertensive rats (SHRs) in the active group (n = 13) received Li-ESWT at energy flux density 0.06 mJ/mm² (Aries; Dornier MedTech, Wessling, Germany) twice weekly for 6 weeks. The emitter was set to zero for SHRs in the sham group (n = 12). Erectile function was assessed 4 weeks post-treatment by monitoring intracavernosal pressure (ICP) in response to electrical stimulation of cavernous nerve before and after single dose of 0.3 mg/kg intravenous sildenafil. Cavernosal tissue was then evaluated for collagen/smooth muscle content, neuronal nitric oxide synthase (nNOS), and vascular endothelial factor (CD31) expression.

Outcomes

Erectile function was assessed with ICP, erectile tissue remodeling was studied by smooth muscle/collagen ratio, nNOS and CD31 were semiquantitatively evaluated on cavernosal sections.

Results

The improvement of ICP parameters was greater in Li-ESWT–treated rats compared with controls with and without sildenafil. Sildenafil led to 20% increase in area under the intracavernosal pressure curve measured during the entire response/mean arterial pressure at 10 Hz in ESWT_SHR + sildenafil compared with ESWT_SHR. The smooth muscle/collagen ratio increased 2.5-fold in Li-ESWT compared with sham. Expression of CD31 tended to be increased whereas nNOS was unchanged.

Conclusions

Li-ESWT by Aries may represent an effective noninvasive therapeutic alternative and a relevant add-on therapy to phosphodiesterase type 5 inhibitors for ED in hypertensive patients, and it is suggested that it acts via remodeling of the penile tissue and promoting cavernosal vascularization.

Assaly R, Giuliano F, Clement P, et al. Extracorporeal Shock Waves Therapy Delivered by Aries Improves Erectile Dysfunction in Spontaneously Hypertensive Rats Through Penile Tissue Remodeling and Neovascularization. Sex Med 2019;7:441–450

Add-on Therapy With the α-Blockers Tamsulosin and Naftopidil Improves Voiding Function by Enhancing Neuronal Activity in Prostatic Hyperplasia Rats

Purpose

Benign prostatic hyperplasia (BPH) impacts quality of life in men by causing lower urinary tract symptoms. α1-Adrenoceptor (α1-AR) blockers improve lower urinary tract symptoms. We investigated the efficacy of add-on therapy with α1-AR blockers on BPH rats.

Methods

Rats in the drug-treated groups were orally administered each drug once a day for 30 days after orchiectomy. To induce BPH, rats were castrated and testosterone (20 mg/kg) was injected subcutaneously once per day for 30 days. Cystometry was conducted to measure voiding contraction pressure and the interval contraction time, immunohistochemistry was performed to measure c-Fos and nerve growth factor (NGF) expression in the neuronal voiding centers, and nicotinamide adenine dinucleotide phosphate-diaphorase histochemistry was used to measure nitric oxide synthase (NOS) expression.

Results

Orchiectomy and testosterone injection decreased voiding contraction pressure and the interval contraction time, suggesting BPH symptoms. Voiding contraction pressure and the interval contraction time were greater in the group that received the combination treatment (tamsulosin with naftopidil) than in the tamsulosin monotherapy or naftopidil monotherapy groups. c-Fos, NGF, and NOS expression in the neuronal voiding centers was enhanced by BPH induction. c-Fos, NGF, and NOS expression was suppressed by the combination treatment (tamsulosin with naftopidil) to a greater extent than was the case for tamsulosin monotherapy or naftopidil monotherapy.

Conclusions

Combination therapy of tamsulosin and naftopidil showed greater efficacy for the treatment of BPH than tamsulosin monotherapy or naftopidil monotherapy; therefore, combination therapy can be considered as a novel therapeutic method for BPH.

Roles of autophagy in androgen-induced benign prostatic hyperplasia in castrated rats

The present study investigated the role of androgen in the process of androgen-induced prostate hyperplasia in castrated rats and assessed the role of the phosphoinositide 3-kinase/protein kinase B/mechanistic target of rapamycin (PI3K/Akt/mTOR) pathway in this process. Furthermore, the extent to which autophagy may affect the level of androgen-induced benign prostatic hyperplasia was also explored. A total of 40 Sprague Dawley rats were randomly divided into four groups: Testosterone group, rapamycin group, 3-methyladenine (3-MA) group, and control group. The extent of hyperplasia in prostate tissue the apoptosis and autophagy were assayed. The prostate wet weight, volume and index in the testosterone group were significantly higher compared with the control group (P<0.05) and these factors were significantly lower in the rapamycin group compared with the testosterone group (P<0.05). HE staining demonstrated that prostate hyperplasia was obvious in the testosterone group. Western blotting revealed that caspase-3 levels were higher in the 3-MA group compared with the control group and Bcl-2 was higher in the testosterone group compared with the control group (P<0.05). Furthermore, in the rapamycin group, Bcl-2 protein expression levels were significantly lower than those in the testosterone group (P<0.05). The prostate tissue was analyzed using electron microscopy and autophagy bodies were identified in the rapamycin group. In the process of androgen-induced prostatic hyperplasia in castrated rats, the role of androgen may be related to the PI3K/Akt/mTOR signaling pathway. Rapamycin was able to inhibit the effect of testosterone and promoted prostate tissue hyperplasia by inhibiting the PI3K/Akt pathway. In addition to inhibiting apoptosis in prostate cells, androgen was able to induce rat prostate hyperplasia and may also be related to the promotion of the proliferation of prostate cells.

Erectile Dysfunction and Lower Urinary Tract Symptoms

CONTEXT

Lower urinary tract symptoms (LUTSs) and erectile dysfunction (ED) are substantial health concerns with a significant impact on the overall male quality of life.

OBJECTIVE

To evaluate the available evidence of the association between LUTSs and ED in patients with benign prostatic hyperplasia (BPH), and discuss possible clinical implications for the management of LUTS/BPH.

EVIDENCE ACQUISITION

A systematic review of the existing literature published between 1997 and June 2017 and available in the Medline, Scopus, and Web of Science databases was conducted using both the Medical Subject Heading (MeSH) and free-text protocols. The MeSH search was conducted by combining the following terms: "lower urinary tract symptoms," "LUTS," "benign prostatic hyperplasia," "BPH," "erectile dysfunction," "sexual dysfunction," "BPE," and "benign prostatic enlargement." The Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were followed.

EVIDENCE SYNTHESIS

Several community-based studies in different geographical areas have provided strong evidence of an age-independent association between LUTSs and ED. Several biological mechanisms have been proposed to explain this association, but further research is required to better understand the molecular pathways involved. It is necessary to evaluate the possible impact of the metabolic syndrome treatment on LUTS/ED management. Considering the possible relationship between LUTSs and ED, their impact on the quality of life, and the possible adverse effects associated with LUTS medical treatment, clinicians should always evaluate ED in patients with LUTSs and take the opportunity to evaluate patients reporting ED for LUTSs.

CONCLUSIONS

Data from the peer-reviewed literature suggest the existence of an association between LUTS/BPH and ED, although their casual relationship has not been established yet. Emerging data also suggest that pathophysiological mechanisms involved in the metabolic syndrome are key factors in both disorders. Considering the association, it is also recommended that men presenting with LUTSs or ED should be evaluated for both disorders. A better understanding of the molecular pathways behind this association may also help identify new possible targets and develop novel therapeutic approaches to manage LUTSs and ED.

PATIENT SUMMARY

In this manuscript, we report on all the available evidence linking erectile dysfunction and lower urinary tract symptoms. Our findings suggest the existence of a strong relationship between these two conditions. On the basis of these findings, we recommend that clinicians always explore both conditions in male patients presenting with either of symptoms.

Effects of silodosin, a selective alpha-1A adrenoceptor antagonist, on erectile function in a rat model of partial bladder outlet obstruction

AIM

We investigated the effects of silodosin (selective α_1A -adrenoceptor antagonist) on erectile dysfunction (ED) in a rat model of bladder outlet obstruction.

METHODS

Adult male Sprague-Dawley rats (n = 32) were divided into four groups: (i) sham-operated control; (ii) silodosin-treated (sham) control (0.1 mg/kg/day); (iii) partial bladder outlet obstruction (PBOO); and (iv) silodosin-treated with PBOO. PBOO was induced by ligation of the urethra for 6 weeks. In vivo, erectile responses were monitored by evaluating ratios of intracavernosal pressure (ICP)/mean arterial pressure (MAP). Organ-bath studies were performed on corpus cavernosum (CC) strips. Penises were assessed at baseline for protein expression of neuronal nitric oxide synthase (nNOS) and Rho-associated protein kinase (ROCK2) by Western blot. Immunohistochemistry and Masson trichrome staining were performed for analysis of nNOS protein levels and tissue alterations.

RESULTS

The ratio of ICP/MAP was significantly decreased in obstructed rats (0.26 ± 0.043, P < 0.01) compared to sham-control rats (0.64 ± 0.10), which was restored by the treatment (0.59 ± 0.14, P < 0.01) compared with obstructed rats. Relaxation responses were significantly reduced in strips from the obstructed group. Silodosin restored nitrergic relaxant responses. nNOS expression in the obstructed group decreased, which was improved by treatment. The decreased smooth muscle/collagen ratio in the bladder obstructed group was reversed by the treatment.

CONCLUSIONS

Silodosin improves erectile function in obstructed rats. Further clinical trials are needed to explore fully the potential benefits of silodosin in patients with benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS) in association with ED. Neurourol. Urodynam. 36:597-603, 2017. © 2016 Wiley Periodicals, Inc.

Increased Rho-kinase-mediated prostate contractions associated with impairment of β-adrenergic-cAMP-signaling pathway by chronic nitric oxide deficiency

Impairment of nitric oxide (NO) - cyclic GMP signaling pathway is likely to contribute to human begnin prostate hyperplasia (BPH). In the present study we have used a model of chronic NO synthesis inhibition to evaluate the functional alterations of prostate smooth muscle (PSM) machinery, and involvement of Rho-kinase pathway. Wistar rats were treated with the NO inhibitor N(ω)-nitro-l-arginine methyl ester (L-NAME, 20mg/kg/day; 4 weeks), after which contractile responses to phenylephrine (α1-adrenoceptor agonist; 1nM to 100µM), carbachol (muscarinic agonist; 1nM to 1mM) and α,β-methylene ATP (P2X receptor agonist; 1-10µM), as well as to electrical-field stimulation (EFS; 1-32Hz) were evaluated. PSM relaxations to isoproterenol (non-selective β-adrenoceptor agonist, 0.1nM to 10µM) and sodium nitroprusside (NO donor, 1nM to 10mM) were also evaluated. The ratio prostate weight/body weight was 22% greater (P<0.05) in L-NAME compared with control group. The PSM contractions to phenylephrine, carbachol and α,β-methylene ATP were higher in L-NAME (Emax: 3.85±0.25, 3.52±0.35 and 2.03±0.2mN, respectively) compared with control group (Emax: 3.08±0.17, 2.37±0.18 and 1.57±0.18mN, respectively). The PSM contractions induced by EFS were also significantly greater in L-NAME group. Prior incubation with the Rho-kinase inhibitor Y27632 (1µM) fully reversed the enhanced contractions to phenylephrine and carbachol. Isoproterenol-induced PSM relaxations were 34% lower in L-NAME group, which was associated with reduced levels of cAMP in prostate tissue. The relaxations to sodium nitroprusside remained unaltered in L-NAME group. In summary, chronic NO deficiency leads to increased Rho-kinase-mediated PSM contractile responses accompanied by impairment of β-adrenergic-cAMP-signaling pathway.

Effect of short- and long-term sildenafil treatment on erectile dysfunction in rats with partial bladder outlet obstruction

AIM

Lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) are frequent problems in older men worldwide. We evaluated the effect of short- and long-term sildenafil treatment on erectile function in rats with surgically induced partial bladder outlet obstruction (PBOO).

METHODS

A total of 60 male Sprague-Dawley rats were randomized in five groups: (1) control (sham-operated); (2) PBOO for 3 weeks; (3) PBOO for 6 weeks; (4) sildenafil (1.5 mg/rat/day) treated PBOO for 3 weeks; and (5) sildenafil treated PBOO for 6 weeks. We assessed erectile function by measuring intracavernous pressures (ICP), mean arterial pressure (MAP) and total ICP after cavernous nerve stimulation. Corpus cavernous smooth muscle (CCSM) strips were isolated and evaluated for relaxation responses using organ-bath preparation. Neuronal nitric oxide synthase (nNOS) expression was determined immunohistochemically.

RESULTS

Experimental PBOO at 3 and 6 weeks showed decreased erectile response based on ICP/MAP ratio, total ICP and decreased expression of nNOS, which returned to normal after prolonged daily treatment with sildenafil. CCSM strips from PBOO rats displayed reduced relaxation responses to both electrical field stimulation (EFS) and acetylcholine (ACh) as well as nNOS enzyme intensity when compared to untreated PBOO group, which was reversed by treatment with sildenafil for 6 weeks.

CONCLUSIONS

Daily sildenafil treatment prevents development of ED in PBOO rats in a time dependent manner. Further studies are needed to explore the effectiveness of sildenafil in patients with BPH/LUTS in association with ED.

A novel method to establish a rat ED model using internal iliac artery ligation combined with hyperlipidemia

Objective

To investigate a novel method, namely using bilateral internal iliac artery ligation combined with a high-fat diet (BCH), for establishing a rat model of erectile dysfunction (ED) that, compared to classical approaches, more closely mimics the chronic pathophysiology of human ED after acute ischemic insult.

Materials and Methods

Forty 4-month-old male Sprague Dawley rats were randomly placed into five groups (n = 8 per group): normal control (NC), bilateral internal iliac artery ligation (BIIAL), high-fat diet (HFD), BCH, and mock surgery (MS). All rats were induced for 12 weeks. Copulatory behavior, intracavernosal pressure (ICP), ICP/mean arterial pressure, hematoxylin-eosin staining, Masson's trichrome staining, serum lipid levels, and endothelial and neuronal nitric oxide synthase immunohistochemical staining of the cavernous smooth muscle and endothelium were assessed. Data were analyzed by SAS 8.0 for Windows.

Results

Serum total cholesterol and triglyceride levels were significantly higher in the HFD and BCH groups than the NC and MS groups. High density lipoprotein levels were significantly lower in the HFD and BCH groups than the NC and MS groups. The ICP values and mount and intromission numbers were significantly lower in the BIIAL, HFD, and BCH groups than in the NC and MS groups. ICP was significantly lower in the BCH group than in the BIIAL and HFD groups. Cavernous smooth muscle and endothelial damage increased in the HFD and BCH groups. Cavernous smooth muscle to collagen ratio, nNOS and eNOS staining decreased significantly in the BIIAL, HFD, and BCH groups compared to the NC and MS groups.

Conclusions

The novel BCH model mimics the chronic pathophysiology of ED in humans and avoids the drawbacks of traditional ED models.

A single low dose of cadmium exposure induces benign prostate hyperplasia like condition in rat: A novel benign prostate hyperplasia rodent model

Abnormal prostate growth is the most prevalent pathological sign in aged human males, as reflected by high incidence of benign prostate hyperplasia (BPH) and prostate cancer. In spite of the high prevalence, the etiology and pathophysiology of BPH is unclear due to the lack of any established rodent model for study. It has been demonstrated that the cadmium (Cd) mimics the activity of androgen or estrogen by interacting with the steroid hormone receptors in the prostate and elicits BPH, but the specific receptor which binds to Cd is still unknown. Our lab studies with BPH patients highlighted a strong co-relation between smokings with increased Cd content. Changes in the maximum urinary flow rate (Qmax) and prostatic acid phosphatase (PAP) level further supports that Cd can induce BPH like condition. Therefore, the present study was aimed to induce BPH like condition in rats by Cd administration. The dose of cadmium was standardized in an age- and time-dependent manner, which was further examined by prostate weight, histology, and PAP levels that elucidated the pathogenesis of BPH. Further to understand the molecular basis, steroid hormone receptor antagonist experiment was performed. Gene expression and immunohistochemistry data suggest that Cd induces hyperplasia like condition by activating the androgen receptor and estrogen receptor-α and suppresses the action of estrogen receptor-β. The experimental model used here is a cost effective, less time consuming and potentially valuable tool for investigating the respective functions of epithelial and stromal hormone receptors. The applicability of this model would be helpful in understanding the pathogenesis of BPH and its progression.

Pathogenic mechanisms linking benign prostatic hyperplasia, lower urinary tract symptoms and erectile dysfunction

INTRODUCTION

Erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) caused by benign prostatic hyperplasia (BPH) are clinical entities very prevalent in men aged over 50 years. There is evidence that both may have a common pathophysiology.

OBJECTIVE

The objective of this study was to conduct a literature review aiming to show theories and hypotheses that justify a single pathophysiology for ED and LUTS/BPH.

METHODS

A search in Medline using the keywords of the Medical Subject Headings (MESH) 'erectile dysfunction' and 'lower urinary tract symptoms' in all fields of the database up to 15 December 2012. This search found 198 relevant articles that were analyzed.

RESULTS

The data and articles were divided according to the type of evidence found. There are strong epidemiological data showing that LUTS/BPH is a risk factor for developing ED. Several experimental models demonstrated partial obstruction of the bladder in animals causes voiding disorders as well as a negative impact on erectile function of the operated animals. The increased adrenergic tonus in animals leads to prostate growth and urodynamic conditions similar to those found in men with LUTS and ED. Arteriosclerosis may lead to loss of vesical complacency, urinary tract obstruction and fibrosis of the cavernous bodies. The use of phosphodiesterase type 5 inhibitors (PDE-5i) and/or alpha-adrenergic blockers to treat ED and LUTS/BPH reinforces the hypothesis that, at least in some patients, both clinical pictures may have the same pathophysiology.

Bladder outlet obstruction triggers neural plasticity in sensory pathways and contributes to impaired sensitivity in erectile dysfunction

Lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) are common problems in aging males worldwide. The objective of this work was to evaluate the effects of bladder neck nerve damage induced by partial bladder outlet obstruction (PBOO) on sensory innervation of the corpus cavernosum (CC) and CC smooth muscle (CCSM) using a rat model of PBOO induced by a partial ligation of the bladder neck. Retrograde labeling technique was used to label dorsal root ganglion (DRG) neurons that innervate the urinary bladder and CC. Contractility and relaxation of the CCSM was studied in vitro, and expression of nitric oxide synthase (NOS) was evaluated by Western blotting. Concentration of the sensory neuropeptides substance P (SP) and calcitonin gene-related peptide was measured by ELISA. Partial obstruction of the bladder neck caused a significant hypertrophy of the urinary bladders (2.5-fold increase at 2 wk). Analysis of L6-S2 DRG sections determined that sensory ganglia received input from both the urinary bladder and CC with 5-7% of all neurons double labeled from both organs. The contractile responses of CC muscle strips to KCl and phenylephrine were decreased after PBOO, followed by a reduced relaxation response to nitroprusside. A significant decrease in neuronal NOS expression, but not in endothelial NOS or protein kinase G (PKG-1), was detected in the CCSM of the obstructed animals. Additionally, PBOO caused some impairment to sensory nerves as evidenced by a fivefold downregulation of SP in the CC (P ≤ 0.001). Our results provide evidence that PBOO leads to the impairment of bladder neck afferent innervation followed by a decrease in CCSM relaxation, downregulation of nNOS expression, and reduced content of sensory neuropeptides in the CC smooth muscle. These results suggest that nerve damage in PBOO may contribute to LUTS-ED comorbidity and trigger secondary changes in the contraction/relaxation mechanisms of CCSM.