Increased Level of Tumor Necrosis Factor-Alpha (TNF-α) Leads to Downregulation of Nitrergic Neurons Following Bilateral Cavernous Nerve Injury and Modulates Penile Smooth Tone.

BACKGROUND: Erectile dysfunction (ED) after injury to peripheral cavernous nerve (CN) is partly a result of inflammation in pelvic ganglia, suggesting that ED may be prevented by inhibiting neuroinflammation. AIM: The aim of this study is to examine temporal changes of TNF-α, after bilateral CN injury (BCNI), to evaluate effect of exogenous TNF-α on neurite outgrowth from major pelvic ganglion (MPG), and to investigate effect of TNF-α signal inhibition to evaluate effects of TNF-α on penile tone with TNF-α receptor knockout mice (TNFRKO). METHODS: Seventy Sprague-Dawley rats were randomized to undergo BCNI or sham surgery. Sham rats' MPGs were harvested after 48 hours, whereas BCNI groups' MPGs were at 6, 12, 24, 48 hours, 7, or 14 days after surgery. qPCR was used to evaluate gene expression of markers for neuroinflammation in MPGs. Western blot was performed to evaluate TNF-α protein amount in MPGs. MPGs were harvested from healthy rats and cultured in Matrigel with TNF-α. Neurite outgrowth from MPGs was measured after 3 days, and TH and nNOS immunofluorescence was assessed. Wild type (WT) and TNFRKO mice were used to examine effect of TNF-α inhibition on smooth muscle function after BCNI. MPGs were harvested 48 hours after sham or BCNI surgery to evaluate gene expression of nNOS and TH. OUTCOMES: Gene expression of TNF-α signaling pathway, Schwann cell and macrophage markers, protein expression of TNF-α in MPGs, and penile smooth muscle function to electrical field stimulation (EFS) were evaluated. RESULTS: BCNI increased gene and protein expression of TNF-α in MPGs. Exogenous TNF-α inhibited MPG neurite outgrowth. MPGs cultured with TNF-α had decreased gene expression of nNOS (P < .05). MPGs cultured with TNF-α had shorter nNOS+ neurites than TH+ neurites (P < .01). Gene expression of nNOS was enhanced in TNFRKO mice compared to WT mice (P < .01). WT mice showed enhanced smooth muscle contraction of penises of WT mice was enhanced to EFS, compared to TNFKO (P < .01). Penile smooth-muscle relaxation to EFS was greater in TNFKO mice compared to WT (P < .01). CLINICAL TRANSLATION: TNF-α inhibition may prevent ED after prostatectomy. STRENGTH/LIMITATIONS: TNF-α inhibition might prevent loss of nitrergic nerve apoptosis after BCNI and preserve corporal smooth muscle function but further investigation is required to evaluate protein expression of nNOS in MPGs of TNFKO mice. CONCLUSIONS: TNF-α inhibited neurite outgrowth from MPGs by downregulating gene expression of nNOS and TNFRKO mice showed enhanced gene expression of nNOS and enhanced penile smooth-muscle relaxation. Matsui H, Sopko NA, Campbell JD, et al. Increased Level of Tumor Necrosis Factor-Alpha (TNF-α) Leads to Downregulation of Nitrergic Neurons Following Bilateral Cavernous Nerve Injury and Modulates Penile Smooth Tone. J Sex Med 2021;18:1181-1190.

Functional and molecular characterisation of the bilateral pelvic nerve crush injury rat model for neurogenic detrusor underactivity.

OBJECTIVES: To create a rat model for neurogenic detrusor underactivity (DU) by bilateral pelvic nerve crush injury (BPNI) and to study temporal changes in detrusor contractility and morphology. MATERIALS AND METHODS: Male Sprague-Dawley rats were subjected to BPNI or sham surgery and evaluated at 1, 3 and 9 weeks after surgery. Bladder function was determined in vivo by awake cystometry, micturition pattern analysis, and 24-h urine collection. Bladders were harvested for in vitro pharmacological investigation by isometric tension recording. Bladders and major pelvic ganglia were investigated by quantitative reverse transcription-polymerase chain reaction and histochemistry. RESULTS: Overflow incontinence was observed at 1 week after BPNI. At 3 and 9 weeks after BPNI, rats showed a bladder phenotype characteristic for DU with increased post-void residual urine volumes, reduced voiding efficiencies, and lower maximum pressures. In isolated bladder strips, contractile responses to KCl, carbachol, and α,ß-methylene adenosine 5'-triphosphate (α,ß-mATP) were preserved. On the other hand, neural-induced contractility was reduced after BPNI, in line with reduced expression of protein gene product 9.5 and choline acetyltransferase in the major pelvic ganglion at 1 week after BPNI. The bladder-to-body weight ratio and detrusor thickness increased after BPNI, indicating detrusor hypertrophy to compensate for the reduced neural input. CONCLUSIONS: BPNI induces a rat model for neurogenic DU. In this model, the detrusor maintains its contractility but denervation of the detrusor was observed.

Intratunical injection of stromal vascular fraction prevents fibrosis in a rat model of Peyronie's disease.

OBJECTIVE: To investigate whether local injection of autologous adipose stromal vascular fraction (SVF) can prevent the development of fibrosis and elastosis in the tunica albuginea (TA) using a rat model of the acute phase of Peyronie's disease (PD). METHODS: A total of 24 male 12-week-old Sprague-Dawley rats were divided into three equal groups: sham; PD without treatment (transforming growth factor-ß [TGF -ß]); and PD treated with SVF 1 day after disease induction. Sham rats received two injections of vehicle into the TA 1 day apart. TGF -ß rats received TGF- ß1 injection and injection of vehicle 1 day later. SVF rats received TGF-ß1 injection, followed by SVF 1 day later. One month after treatment, all rats underwent measurement of intracavernosal pressure and mean arterial pressure during electrostimulation of the cavernous nerve. The rats were then killed and penises were harvested for histology and Western blot analysis. RESULTS: Erectile function was moderately reduced in the TGF-ß group and was significantly improved after SVF treatment (P < 0.05). PD rats developed areas of fibrosis with a significant upregulation of collagen III, collagen I and elastin protein expression. These fibrotic changes were prevented when treated with SVF. CONCLUSIONS: Local injection of SVF may represent treatment for the acute phase of PD.

Use of fosfomycin as targeted antibiotic prophylaxis before prostate biopsy: A prospective randomized study.

OBJECTIVES: To investigate whether switching ciprofloxacin to fosfomycin in the case of fluoroquinolone-resistant rectal bacteria influences the incidence of infectious complications after transrectal prostate biopsy. METHODS: From December 2015 until December 2017, patients undergoing prostate biopsy were randomly assigned to a control group or an intervention group in a prospective, open-label fashion at three different centers. The presence of fluoroquinolone-resistant organisms was detected by rectal swabs. Patients in the control group received ciprofloxacin. Patients in the intervention group received fosfomycin instead of ciprofloxacin in the case of fluoroquinolone-resistant bacteria on rectal swab culture. The primary end-point was the difference in occurrence of major (febrile) and minor (afebrile) infections between both groups. RESULTS: A total of 102 patients were randomized to the control group, and 102 patients to the intervention group. In the control group, nine complications occurred, of which five were major febrile complications. In the intervention group, six complications occurred, of which four were major febrile complications. The total number of complications (major and minor) did not differ between both groups (P = 0.59). A subgroup analysis of patients with fluoroquinolone-resistant bacteria on rectal swab showed five complications in the control group and one complication in the intervention group (P = 0.09). CONCLUSIONS: This represents the first prospective randomized study using rectal cultures for targeted antibiotic prophylaxis. Study findings show promising results for use of fosfomycin in patients with fluoroquinolone resistance.

Galanin Administration Partially Restores Erectile Function After Cavernous Nerve Injury and Mediates Endogenous Nitrergic Nerve Outgrowth In Vitro.

BACKGROUND: Previously, we found that the neuropeptide galanin was strongly upregulated soon after bilateral cavernous nerve injury (BCNI) and that galanin and its receptors were expressed in nitrergic erectile innervation. Galanin has been observed to exert neuroregenerative effects in dorsal root ganglion neurons, but evidence for these effects in the major pelvic ganglion (MPG) after BCNI is lacking. AIM: To evaluate the neurotropic effects of galanin receptor agonists and antagonists in vitro in nitrergic neurons and MPG and in vivo in rats after BCNI. METHODS: Male Sprague-Dawley rats underwent BCNI and sham surgery. Organ culture and single-cell neuron culture of the MPG were performed. Osmotic pump treatment with the galanin agonist in vivo and measurement of erectile response to electrostimulation after BCNI, immunohistochemical localization of galanin and receptors in the human neurovascular bundle, and myographic analysis of rat corpus cavernosum smooth muscle relaxation to galanin receptor agonists were investigated. OUTCOMES: Neurite outgrowth in vitro and erectile response to electrostimulation after BCNI in vivo, immunohistochemical localization of galanin and receptors, and penile muscle relaxation in vitro. RESULTS: Galanin showed neurotrophic action in vitro and inhibition of endogenous galanin significantly impaired neurite outgrowth in nitrergic but not in sympathetic MPG neurons. In vivo administration of a selective galanin receptor-2 agonist, M1145, resulted in partial recovery of erectile function (EF) after BCNI. Galanin did not act as a direct vasodilator on corpus cavernosum muscle strips. CLINICAL TRANSLATION: Endogenous neurotrophins such as galanin could be used as a strategy to improve EF for patients after BCNI from radical prostatectomy. STRENGTHS AND LIMITATIONS: We evaluated the effect of galanin on nerve regeneration and EF recovery in vivo and in vitro. Limitations include the lack of washout period for the in vivo experiment and absence of differences in the expression of neuronal markers between treatment groups. CONCLUSIONS: We identified galanin as a potential endogenous mechanism for nerve regeneration after BCNI, which could play a physiologic role in EF recovery after radical prostatectomy. In vivo treatment with exogenous galanin was beneficial in enhancing EF recovery after BCNI, but further research is necessary to understand the underlying mechanisms. Weyne E, Hannan JL, Gevaert T, et al. Galanin Administration Partially Restores Erectile Function After Cavernous Nerve Injury and Mediates Endogenous Nitrergic Nerve Outgrowth In Vitro. J Sex Med 2018;15:480-491.

Characterization of voiding function and structural bladder changes in a rat model of neurogenic underactive bladder disease.

OBJECTIVES: To create an animal model for neurogenic underactive bladder disease (UAB) and identify markers to describe secondary myogenic changes in the bladder wall. MATERIALS AND METHODS: Male rats underwent either bilateral pelvic nerve injury or sham surgery. Four weeks after surgery functional evaluation was performed and tissue was harvested. Functional evaluation consisted of analysis of voiding pattern, 24-h urine collection in a metabolic cage, in vivo cystometry and in-vitro contractile function assessment. PCR and immunohistochemical localization of different smooth muscle cell and extracellular matrix markers was performed on bladder strips. RESULTS: After pelvic nerve injury, dry bladder weight increased and voiding contractions were absent, resulting in overflow incontinence. In-vitro contractile response to carbachol was decreased. This was paired with an upregulation of synthetic smooth muscle cell (SMC) markers mRNA expression such as retinol binding protein 1 (RBP1), myosin 10 (MYH10) and osteopontin (OPN), and a downregulation of contractile SMC marker smoothelin (SMTL). The SMTL/OPN mRNA ratio was 50 times higher in sham bladders compared to PNI bladders. CONCLUSIONS: The loss of in-vivo and in-vitro contractile function following pelvic nerve transection is characterized by a switch from a contractile to synthetic SMC phenotype, which is best characterized by the ratio SMTL/OPN mRNA expression. Modulating this phenotypical switch is a potential target for the development of UAB therapy. We suggest for the first time a set of markers that may be useful to evaluate therapeutic strategies on improvements in bladder wall structure.

Additive effects of the Rho kinase inhibitor Y-27632 and vardenafil on relaxation of the corpus cavernosum tissue of patients with erectile dysfunction and clinical phosphodiesterase type 5 inhibitor failure.

OBJECTIVES: To evaluate the expression of the Rho/Rho-associated protein kinase (ROCK) pathway in the corpus cavernosum of patients with severe erectile dysfunction (ED) compared with healthy human corpus cavernosum, and to test the functional effects of two Rho kinase inhibitors (RKIs) on erectile tissue of patients with severe ED, which did not respond to phosphodiesterase type 5 inhibitors (PDE5Is). PATIENTS AND METHODS: Human corpus cavernosum samples were obtained after consent from men undergoing penile prosthesis implantation (n = 7 for organ bath experiments, n = 17 for quantitative PCR [qPCR]). Potent control subjects (n = 5) underwent penile needle biopsy. qPCR was performed for the expression of RhoA and ROCK subtypes 1 and 2. Immunohistochemistry staining against ROCK and α smooth muscle actin (αSMA) was performed on the corpus cavernosum of patients with ED. Tissue strips were precontracted with phenylephrine and incubated with 1 µm of the PDE5I vardenafil or with DMSO (control). Subsequently, increasing concentrations of the RKIs azaindole or Y-27632 were added, and relaxation of tissue was quantified. RESULTS: The expression of ROCK1 was unchanged (P > 0.05), while ROCK2 (P < 0.05) was significantly upregulated in patients with ED compared with controls. ROCK1 and ROCK2 protein colocalized with αSMA, confirming the presence of this kinase in cavernous smooth muscle cells and/or myofibroblasts. After incubation with DMSO, 10 µm azaindole and 10 µm Y-27632 relaxed precontracted tissues with 49.5 ± 7.42% (P = 0.1470 when compared with vehicle) and 85.9 ± 10.3% (P = 0.0016 when compared with vehicle), respectively. Additive effects on relaxation of human corpus cavernosum were seen after preincubation with 1 µm vardenafil. CONCLUSION: The RKI Y-27632 causes a significant relaxation of corpus cavernosum in tissue strips of patients with severe ED. The additive effect of vardenafil and Y-27632 shows that a combined inhibition of Rho-kinase and phosphodiesterase type 5 could be a promising orally administered treatment for severe ED.

M1 Macrophages Are Predominantly Recruited to the Major Pelvic Ganglion of the Rat Following Cavernous Nerve Injury.

INTRODUCTION: Neurogenic erectile dysfunction is a common sequela of radical prostatectomy. The etiology involves injury to the autonomic cavernous nerves, which arise from the major pelvic ganglion (MPG), and subsequent neuroinflammation, which leads to recruitment of macrophages to the injury site. Currently, two macrophage phenotypes are known: neurotoxic M1 macrophages and neuroprotective M2 macrophages. AIM: To examine whether bilateral cavernous nerve injury (BCNI) in a rat model of erectile dysfunction would increase recruitment of neurotoxic M1 macrophages to the MPG. METHODS: Male Sprague-Dawley rats underwent BCNI and the MPG was harvested at various time points after injury. The corpora cavernosa was used to evaluate tissue myographic responses to electrical field stimulation ex vivo. Quantitative real-time polymerase chain reaction was used to examine the gene expression of global macrophage markers, M1 macrophage markers, M2 macrophage markers, and cytokines and chemokines in the MPG. Mathematical calculation of the M1/M2 index was used to quantify macrophage changes temporally. Western blot of MPG tissues was used to evaluate the protein amount of M1 and M2 macrophage markers quantitatively. Immunohistochemistry staining of MPGs for CD68, CD86, and CD206 was used to characterize M1 and M2 macrophage infiltration. MAIN OUTCOME MEASURES: Corpora cavernosa responsiveness ex vivo; gene (quantitative real-time polymerase chain reaction) and protein (western blot) expressions of M1 and M2 markers, cytokines, and chemokines; and immunohistochemical localization of M1 and M2 macrophages. RESULTS: BCNI impaired the corporal parasympathetic-mediated relaxation response to electrical field stimulation and enhanced the contraction response to electrical field stimulation. Gene expression of proinflammatory (Il1b, Il16, Tnfa, Tgfb, Ccl2, Ccr2) and anti-inflammatory (Il10) cytokines was upregulated in the MPG 48 hours after injury. M1 markers (CD86, inducible nitric oxide synthase, interleukin-1ß) and M2 markers (CD206, arginase-1, interleukin-10) were increased after BCNI in the MPG, with the M1/M2 index above 1.0 indicating that more M1 than M2 macrophages were recruited to the MPG. Protein expression of the M1 macrophage marker (inducible nitric oxide synthase) was increased in MPGs after BCNI. However, the protein amount of M2 macrophage markers (arginase-1) remained unchanged. Immunohistochemical characterization demonstrated predominant increases in M1 (CD68+CD86+) macrophages in the MPG after BCNI. CONCLUSION: These results suggest that an increase in M1 macrophage infiltration of the MPG after BCNI is associated with impaired neurogenically mediated erectile tissue physiology ex vivo and thus has significant implications for cavernous nerve axonal repair. Future studies are needed to demonstrate that inhibition of M1 macrophage recruitment prevents erectile dysfunction after CNI.

Advances in stem cell research for the treatment of male sexual dysfunctions.

PURPOSE OF REVIEW: To summarize recent literature on basic stem cell research in erectile dysfunction in cavernous nerve injury, aging, diabetes, and Peyronie's disease and to provide a perspective on clinical translation of these cellular therapies. RECENT FINDINGS: Stem cell research has been concentrated on mesenchymal stem (stromal) cells from bone marrow and adipose tissue. Application of both cell types has produced positive effects on erectile function in various animal models of erectile dysfunction. In acute animal models, such as cavernous nerve injury-induced erectile dysfunction and chemically induced Peyronie's disease, engraftment and differentiation have not been observed, and stem cells are believed to interact with the host tissue in a paracrine fashion, whereas in chronic disease models some evidence suggests both engraftment and paracrine factors may support improved function. Clinical trials are now investigating therapeutic efficacy of cellular therapy, whereas the first safety studies in humans have recently been published. SUMMARY: Evidence from preclinical studies has established stem cells as a potential curative treatment for erectile dysfunction and early phase clinical trials are currently performed.

Idiopathic Partial Thrombosis (IPT) of the Corpus Cavernosum: A Hypothesis-Generating Case Series and Review of the Literature.

INTRODUCTION: Idiopathic partial thrombosis (IPT) of the corpus cavernosum is a rare condition. The etiology is not fully understood; however, the presence of an either or not congenital web in these patients may contribute to the development of IPT. AIM: The aim of this study was to describe 18 new IPT cases and compare these with 38 cases found in the literature. METHODS: A multicenter retrospective analysis was performed. Descriptive statistics are given. MAIN OUTCOME MEASURES: The main outcome measures used were clinical presentation, clinical and radiographical diagnostics, treatment and resolution of symptoms. RESULTS: Patients most frequently presented with perineal swelling (10/18; 56%) and pain (13/18; 72%), unilateral (12/18; 67%) or bilateral (4/18; 22%), and pain during erection (10/18; 72%). Penile curvature, dysuria or fever (each 1/18; 6%) were uncommon presenting symptoms. In our series, magnetic resonance imaging demonstrated a fibrous web in the corpus cavernosum in 100% of cases and was more bilaterally (11/18; 61%) than unilaterally (7/18; 39%) diagnosed. Cycling was found to be a provocative factor for IPT occurrence in patients at risk as 61% (11/18) of patients reported being a frequent cyclist with the episode of IPT occurring immediately after or during cycling activity in 8 out of 18 patients (8/18; 44%). In five centers, 15 patients were treated conservatively, the majority being treated with therapeutic doses of low molecular weight heparin and simultaneous anti-aggregant therapy. In one center, all three patients were treated with a surgical approach. Complete resolution of symptoms was noted in only 50% of cases. CONCLUSION: IPT is a condition that presents typically with perineal pain and swelling. Cycling is often seen as a provocative factor, while the presence of a fibrous web at the level of the crurocavernosal junction is the underlying disorder allowing for entrapment of blood in the crura. Conservative treatment provides a reasonably good outcome in most cases. For therapy resistant cases, surgery can be considered.

Increased expression of the neuroregenerative peptide galanin in the major pelvic ganglion following cavernous nerve injury.

INTRODUCTION: Erectile dysfunction (ED) remains a frequent complication of radical prostatectomy due to injury to the cavernous nerves (CNs). A recent microarray showed the neuropeptide galanin to be one of the most strikingly upregulated genes in the rat major pelvic ganglion (MPG) after bilateral CN crush injury (BCNI). AIM: The aim of this study is to evaluate the temporal regulation of galanin in the MPG after BCNI and its relationship to functional nerve regeneration. METHODS: Changes in galanin, galanin receptor (galR), and c-JUN mRNA expression were assessed in Sprague-Dawley rats after sham operation (n = 10) and at 48 hours (n = 10), 7 (n = 10), 14 (n = 5), 21 (n = 5), 30 (n = 5), and 60 (n = 5) days after BCNI using quantitative PCR. Erectile function was assessed by measuring intracavernous pressure (ICP) divided by mean arterial pressure (MAP) during CN electrostimulation. Immunohistochemistry was performed on the MPG in sham-operated animals and 5 days after BCNI. MAIN OUTCOME MEASURES: ICP/MAP upon CN stimulation; galanin, galR1, -2, -3, and c-JUN mRNA expression at various time points after BCNI; and nNOS, galanin, and galR distribution in the MPG of sham-operated rats and after BCNI. RESULTS: After BCNI, ICP/MAP values quickly deteriorate, while after 60 days, spontaneous restoration of erectile responses to CN stimulation is observed, reflecting CN regeneration. Galanin mRNA in the MPG is up to 186-fold upregulated compared with sham-operated rats at 48 hours and 7 days after BCNI and gradually declines with increasing time from injury, whereas galanin receptor expressions decrease and c-JUN gradually increases. Galanin expression shows a strong inverse correlation with erectile responses to CN stimulation with time from injury. Injured MPGs show a colocalization between galanin- and nNOS-positive neuronal cell population in the MPG. CONCLUSIONS: Galanin is upregulated in the MPG in the early phase after CN injury after which it gradually decreases and is present in nNOS-positive neurons of the ganglion. We hypothesize that galanin upregulation is an important factor in the endogenous neuroregenerative response to CN injury.

E. coli bacterial meningitis after transrectal prostate biopsy under antibiotic prophylaxis: a case report and literature review.

Prostate biopsy, a frequently performed procedure, is not harmless. In rare cases, life-threatening complications occur. We document a potential lethal bacterial meningitis after transrectal biopsy. In addition to our overview of all previously documented cases, we highlight the evidence of prevention of infectious complications when performing a prostate biopsy.

Focusing on sexual rehabilitation besides penile rehabilitation following radical prostatectomy is important.

Erectile dysfunction is commonly reported after radical prostatectomy. Besides the loss of erections, sexual life after prostatectomy is impacted by urinary incontinence, orgasmic dysfunction, and psychological stress. In this review, we describe classical medical therapies used for erectile function rehabilitation such as PDE5 inhibitors and injection therapy. A vast amount of data support the idea of focusing on restoration of sexual function on top of erectile function after prostatectomy. The important strategies described to rehabilitate sexual function include pelvic floor muscle therapy, couple therapy, appropriate preoperative counseling, and focusing on non-penetrative alternatives. A multidisciplinary approach and including the partner is important. Erectile function alone is not sufficient for satisfactory sexual experience and may not be used as a proxy for sexual quality of life. Adding full-spectrum sexual rehabilitation to a standard penile rehabilitation regimen has the highest chances of obtaining satisfactory sexual outcomes in men and their partners after radical prostatectomy.

Intratunical injection of autologous adipose stromal vascular fraction reduces collagen III expression in a rat model of chronic penile fibrosis.

Previous studies have shown that the injection of adipose stem cells and stromal vascular fraction(SVF) into the tunica albuginea (TA) during the inflammatory phase in a rat model of Peyronie's disease(PD) prevented the development of TA fibrosis. Our aim was to investigate whether local injection of SVF can reduce established fibrosis in a rat model of chronic phase of PD. Eighteen-male 12-wk-old Sprague-Dawley rats were divided in three equal groups: sham, PD without treatment (PD) and PD treated with SVF(PD-SVF). Sham rats underwent 2 injections of vehicle into the TA one month apart. PD rats underwent TGF-ß1 injection and injection of vehicle one month later. PD-SVF rats underwent TGF-ß1 injection followed by SVF (1-million cells) one month later. One month after the last treatment, the animals, n = 6 rats per group, underwent measurement of intracorporal and mean arterial pressure during electrostimulation of the cavernous nerve. Following euthanasia, penises were harvested for in-vitro study. Erectile function was not statistically significantly different between groups. PD animals developed subtunical areas of fibrosis and elastosis with upregulation of collagen III protein. These fibrotic changes were reversed after injection of SVF. We provide evidence that local injection of SVF reverses TA fibrosis in a rat model of chronic phase of PD.

European Society for Sexual Medicine Consensus Statement on the Use of the Cavernous Nerve Injury Rodent Model to Study Postradical Prostatectomy Erectile Dysfunction.

INTRODUCTION: Rodent animal models are currently the most used in vivo model in translational studies looking into the pathophysiology of erectile dysfunction after nerve-sparing radical prostatectomy. AIM: This European Society for Sexual Medicine (ESSM) statement aims to guide scientists toward utilization of the rodent model in an appropriate, timely, and proficient fashion. METHODS: MEDLINE and EMBASE databases were searched for basic science studies, using a rodent animal model, looking into the consequence of pelvic nerve injury on erectile function. MAIN OUTCOME MEASURES: The authors present a consensus on how to best perform experiments with this rodent model, the details of the technique, and highlight possible pitfalls. RESULTS: Owing to the specific issue-basic science-Oxford 2011 Levels of Evidence criteria cannot be applied. However, ESSM statements on this topic will be provided in which we summarize the ESSM position on various aspects of the model such as the use of the Animal Research Reporting In Vivo Experiments guideline and the of common range parameter for nerve stimulation. We also highlighted the translational limits of the model. CONCLUSION: The following statements were formulated as a suggestive guidance for scientists using the cavernous nerve injury model. With this, we hope to standardize and further improve the quality of research in this field. It must be noted that this model has its limitations. Weyne E, Ilg MM, Cakir OO, et al. European Society for Sexual Medicine Consensus Statement on the Use of the Cavernous Nerve Injury Rodent Model to Study Postradical Prostatectomy Erectile Dysfunction. Sex Med 2020;8:327-337.

Intravesical Activation of the Cation Channel TRPV4 Improves Bladder Function in a Rat Model for Detrusor Underactivity.

BACKGROUND: Improvement of bladder emptying by modulating afferent nerve activity is an attractive therapeutic strategy for detrusor underactivity. Transient receptor potential vanilloid 4 (TRPV4) is a sensory ion channel in urothelial cells that contribute to the detection of bladder filling. OBJECTIVE: To investigate the potential benefit of intravesical TRPV4 agonists in a pelvic nerve injury rat model for detrusor underactivity. DESIGN, SETTING, AND PARTICIPANTS: Female wild-type and Trpv4 knockout rats underwent sham surgery or bilateral pelvic nerve injury (bPNI). Four weeks later, rats underwent cystometry with infusion of the TRPV4 agonist GSK1016790A. Bladders were harvested for in vitro pharmacological studies, quantitative reverse polymerase chain reaction and immunohistochemistry. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Data are expressed as median ± interquartile range. Statistical comparisons were made using the Mann-Witney U test and Wilcoxon signed rank test as appropriate. RESULTS AND LIMITATIONS: Rats with bPNI showed a phenotype characteristic of detrusor underactivity with lower-amplitude voiding contractions, decreased voiding frequency, and increased postvoid residual. Intravesical application of GSK1016790A increased voiding frequency and reduced postvoid residual in wild-type, but not Trpv4-/-, rats. In isolated bladder strips, GSK1016790A did not induce relevant contractions, indicating that the observed improvements in bladder function are the result of increased afferent signalling through TRPV4 activation, rather than a local effect on the detrusor. The altered urinary phenotype of Trpv4-/- mice was not apparent in the Trpv4-/- rat model, suggesting species-related functional variations. Our results are limited to the preclinical setting in rodents. CONCLUSIONS: Intravesical activation of TRPV4 improves bladder dysfunction after bPNI by increasing afferent signalling. PATIENT SUMMARY: We demonstrate that the sensory protein transient receptor potential vanilloid 4 (TRPV4) can be targeted to improve bladder function in animals that have iatrogenic injury to the nerves innervating the bladder. Further research is required to determine whether these results can be translated to patients with an underactive bladder.

Stem Cells in Male Sexual Dysfunction: Are We Getting Somewhere?

INTRODUCTION: Stem cells for sexual disorders are steadily being introduced into clinical trials. Two conditions of importance are the main target for this line of treatment, especially when regarding the wide array of translational and basic science highlighting the potential advantages of regenerative therapy: erectile dysfunction (ED) and more recently Peyronie disease (PD). Cellular therapy offers a treatment modality that might reverse disease progression. It would be used in a curative setting, in contrast to other pharmaceutical agents that are currently available. AIM: To review basic preclinical studies and recent clinical trials of stem cells on ED and PD. METHODS: A search of the medical literature for the following terms was performed using PubMed: stem cells, cellular therapy, erectile dysfunction, Peyronie's disease, and clinical trial. MAIN OUTCOME MEASURES: A non-systematic narrative review and critical reflection on preclinical and clinical studies administering stem cells for ED and PD in animal models and human subjects. RESULTS: Numerous studies have confirmed the beneficial functional effects of stem cell injection in established animal models on ED and PD. Various stem cell types have been adopted, from embryonic to adult mesenchymal cell types. Each cell type offers distinctive advantages and disadvantages. Diverse administrations of stem cells were investigated, with insignificant variability in the ultimate results. Stem cells appear to have a pronounced paracrine effect, rather than the classic engraftment and differentiation hypothesis. Phase 1 clinical trials using stem cells have not reported any severe adverse events in animals. However, these results cannot be extrapolated to draw any conclusions about efficacy in human patients. CONCLUSION: Stem cells have an established efficacy in preclinical studies and early clinical trials. Studies are currently being published demonstrating the safety of intrapenile injection of autologous bone marrow- and adipose tissue-derived stem cells. Soebadi MA, Milenkovic U, Weyne E, et al. Stem Cells in Male Sexual Dysfunction: Are We Getting Somewhere? Sex Med Rev 2017;5:222-235.

Adipose-derived Stem Cells Counteract Urethral Stricture Formation in Rats.

BACKGROUND: A medical treatment for urethral stricture (US) is not yet available. OBJECTIVE: To evaluate if local injection of human adipose tissue-derived stem cells (hADSC) prevents urethral fibrosis in a rat model of US. DESIGN, SETTING, AND PARTICIPANTS: Male rats were divided into three groups: sham, US, and hADSC (n=12 each). Sham rats received a vehicle injection in the urethral wall. US and hADSCs were incised and injected with the fibrosis-inducer transforming growth factor-ß1 in the urethral wall. INTERVENTION: One day later, hADSCs were injected in the urethral wall of hADSC rats whereas sham and US rats were injected with the vehicle. After 4 wk, the rats underwent cystometries and tissues were then harvested for functional and molecular analyses. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Cystometry, microultrasound, histochemistry, organ bath studies, reverse transcription polymerase chain reaction, and western blot. RESULTS AND LIMITATIONS: US rats exhibited 49-51% shorter micturition intervals, 35-51% smaller micturition volumes and bladder capacity, 33-62% higher threshold pressures and flow pressures, and 35-37% lower bladder filling compliance compared with hADSC-treated rats and sham rats (p<0.05). By ultrasound, US rats had hyperechogenic and thick urethral walls with narrowed lumen compared with sham rats, whereas hADSC rats displayed less extensive urethral changes. Isolated detrusor from US rats exhibited 34-55% smaller contractions than detrusor from sham rats (p<0.05). Corresponding values were 11-35% for isolated detrusors from hADSC rats. Collagen and elastin protein expression were increased in the penile urethras of US rats compared with sham and hADSC groups (p<0.05). Endothelial and inducible nitric oxide synthase expressions were higher (p<0.05) in the hADSC group. Compared with US rats, hADSC rats demonstrated decreased expression of several fibrosis-related genes. Administration of hADSCs was performed at an early stage of US development, which we consider a limitation of the study. CONCLUSIONS: Local injection of hADSCs prevents stricture formation and urodynamic complications in a new rat model for US. PATIENT SUMMARY: Stem cell therapy is effective for preventing urethral stricture in an experimental setting.

Caspase-3 dependent nitrergic neuronal apoptosis following cavernous nerve injury is mediated via RhoA and ROCK activation in major pelvic ganglion.

Axonal injury due to prostatectomy leads to Wallerian degeneration of the cavernous nerve (CN) and erectile dysfunction (ED). Return of potency is dependent on axonal regeneration and reinnervation of the penis. Following CN injury (CNI), RhoA and Rho-associated protein kinase (ROCK) increase in penile endothelial and smooth muscle cells. Previous studies indicate that nerve regeneration is hampered by activation of RhoA/ROCK pathway. We evaluated the role of RhoA/ROCK pathway in CN regulation following CNI using a validated rat model. CNI upregulated gene and protein expression of RhoA/ROCK and caspase-3 mediated apoptosis in the major pelvic ganglion (MPG). ROCK inhibitor (ROCK-I) prevented upregulation of RhoA/ROCK pathway as well as activation of caspase-3 in the MPG. Following CNI, there was decrease in the dimer to monomer ratio of neuronal nitric oxide synthase (nNOS) protein and lowered NOS activity in the MPG, which were prevented by ROCK-I. CNI lowered intracavernous pressure and impaired non-adrenergic non-cholinergic-mediated relaxation in the penis, consistent with ED. ROCK-I maintained the intracavernous pressure and non-adrenergic non-cholinergic-mediated relaxation in the penis following CNI. These results suggest that activation of RhoA/ROCK pathway mediates caspase-3 dependent apoptosis of nitrergic neurons in the MPG following CNI and that ROCK-I can prevent post-prostatectomy ED.

Molecular pathophysiology of cavernous nerve injury and identification of strategies for nerve function recovery after radical prostatectomy.

Despite nerve-sparing techniques, erectile dysfunction remains commonly observed after radical prostatectomy due to neuropraxia to the cavernous nerves during surgery. Preservation and rehabilitation of erectile function after radical prostatectomy remains challenging and many men stay undertreated with the current armory of therapies available in clinical practice. In this article we provide a comprehensive overview of the pathophysiology of the nerve injury occurring during radical prostatectomy and describe different strategies aimed at enhancing neuroprotection and regeneration of the cavernous nerves in order to improve erectile function recovery. These strategies include immunomodulatory, neurotrophic, growth factor and stem cell therapy have convincingly shown improved erectile function and recovery in rat animal models after cavernous nerve injury. Furthermore we describe the rationale for penile rehabilitation with PDE5i out of a neuronal recovery point of view. Many of these strategies reviewed have the potential to optimize erectile function recovery after radical prostatectomy when translated from pre-clinical models to clinical practice.