Krause corpuscles are genital vibrotactile sensors for sexual behaviours.

Krause corpuscles, which were discovered in the 1850s, are specialized sensory structures found within the genitalia and other mucocutaneous tissues1-4. The physiological properties and functions of Krause corpuscles have remained unclear since their discovery. Here we report the anatomical and physiological properties of Krause corpuscles of the mouse clitoris and penis and their roles in sexual behaviour. We observed a high density of Krause corpuscles in the clitoris compared with the penis. Using mouse genetic tools, we identified two distinct somatosensory neuron subtypes that innervate Krause corpuscles of both the clitoris and penis and project to a unique sensory terminal region of the spinal cord. In vivo electrophysiology and calcium imaging experiments showed that both Krause corpuscle afferent types are A-fibre rapid-adapting low-threshold mechanoreceptors, optimally tuned to dynamic, light-touch and mechanical vibrations (40-80 Hz) applied to the clitoris or penis. Functionally, selective optogenetic activation of Krause corpuscle afferent terminals evoked penile erection in male mice and vaginal contraction in female mice, while genetic ablation of Krause corpuscles impaired intromission and ejaculation of males and reduced sexual receptivity of females. Thus, Krause corpuscles of the clitoris and penis are highly sensitive mechanical vibration detectors that mediate sexually dimorphic mating behaviours.

Rab25 is involved in hypospadias via the ß1 integrin/EGFR pathway.

BACKGROUND: Hypospadias is a common congenital abnormality of the penile. Abnormal regulation of critical genes involved in urethral development leads to hypospadias. We used the Rab25-/- mice and foreskin fibroblasts transfected with lentivirus in vitro and in vivo to investigate the role of Rab25 in hypospadias. METHODS: The expression levels of various molecules in tissue samples and foreskin fibroblasts were confirmed using molecular biology methods (western blotting, PCR, immunohistochemistry, etc.). A scanning electron microscope (SEM) was used to visualize the external morphology of genital tubercles (GTs) of gestation day (GD) 18.5 male wild-type (WT) and Rab25-/- mice. RESULTS: An expanded distal cleft and V-shaped urethral opening were observed in GD 18.5 Rab25-/- mice. We demonstrated that Rab25 mediated hypospadias through the ß1 integrin/EGFR pathway. In addition, silencing Rab25 inhibited cell proliferation and migration and promoted apoptosis in the foreskin fibroblasts; Ki-67- and TUNEL-positive cells were mainly concentrated near the urethral seam. CONCLUSION: These findings suggest that Rab25 plays an essential role in hypospadias by activation of ß1 integrin/EGFR pathway, and Rab25 is a critical mediator of urethral seam formation in GD18.5 male fetal mice.

d-Galactose induces the senescence and phenotype switch of corpus cavernosum smooth muscle cells.

Studies regarding age-related erectile dysfunction (ED) based on naturally aging models are limited by their high costs, especially for the acquisition of primary cells from the corpus cavernosum. Herein, d-galactose ( d-gal) was employed to accelerate cell senescence, and the underlying mechanism was explored. As predominant functional cells involved in the erectile response, corpus cavernosum smooth muscle cells (CCSMCs) were isolated from 2-month-old rats. Following this, d-gal was introduced to induce cell senescence, which was verified via ß-galactosidase staining. The effects of d-gal on CCSMCs were evaluated by terminal deoxynucleoitidyl transferase dUTP nick-end labeling (TUNEL), immunofluorescence staining, flow cytometry, western blot, and quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, RNA interference (RNAi) was carried out for rescue experiments. Subsequently, the influence of senescence on the corpus cavernosum was determined via scanning electron microscopy, qRT-PCR, immunohistochemistry, TUNEL, and Masson stainings. The results revealed that the accelerated senescence of CCSMCs was promoted by d-gal. Simultaneously, smooth muscle alpha-actin (alpha-SMA) expression was inhibited, while that of osteopontin (OPN) and Krüppel-like factor 4 (KLF4), as well as fibrotic and apoptotic levels, were elevated. After knocking down KLF4 expression in d-gal-induced CCSMCs by RNAi, the expression level of cellular alpha-SMA increased. Contrastingly, the OPN expression, apoptotic and fibrotic levels declined. In addition, cellular senescence acquired partial remission. Accordingly, in the aged corpus cavernosum, the fibrotic and apoptotic rates were increased, followed by downregulation in the expression of alpha-SMA and the concurrent upregulation in the expression of OPN and KLF4. Overall, our results signaled that d-gal-induced accelerated senescence of CCSMCs could trigger fibrosis, apoptosis and phenotypic switch to the synthetic state, potentially attributed to the upregulation of KLF4 expression, which may be a multipotential therapeutic target of age-related ED.

IL-17A exacerbates corpus cavernosum fibrosis and neurogenic erectile dysfunction by inducing CSMC senescence via the mTORC2-ACACA pathway.

BACKGROUND: Neurogenic erectile dysfunction, characterized by neurological repair disorders and progressive corpus cavernosum fibrosis (CCF), is an unbearable disease with limited treatment success. IL-17A exhibits a complex role in tissue remodelling. Nevertheless, the precise role and underlying mechanisms of IL-17A in CCF under denervation remain unclear. METHODS: PCR array was employed to identified differentially expressed genes between neurogenic ED and normal rats. IL-17A expression and its main target cells were analyzed using Western blotting, immunofluorescence and immunohistochemistry. The phenotypic regulation of IL-17A on corpus cavernosum smooth muscle cells (CSMCs) was evaluated by cell cycle experiments and SA-ß-Gal staining. The mechanism of IL-17A was elucidated using non-target metabolomics and siRNA technique. Finally, IL-17A antagonist and ABT-263 (an inhibitor of B-cell lymphoma 2/w/xL) were utilized to enhance the therapeutic effect in a rat model of neurogenic ED. RESULTS: IL-17A emerged as the most significantly upregulated gene in the corpus cavernosum of model rats. It augmented the senescence transformation and fibrotic response of CSMCs, and exhibited a strong correlation with CCF. Mechanistically, IL-17A facilitated CCF by activating the mTORC2-ACACA signalling pathway, upregulating of CSMCs lipid synthesis and senescence transition, and increasing the secretion of fibro-matrix proteins. In vivo, the blockade of IL-17A-senescence signalling improved erectile function and alleviated CCF in neurogenic ED. CONCLUSIONS: IL-17A assumes a pivotal role in denervated CCF by activating the mTORC2-ACACA signalling pathway, presenting itself as a potential therapeutic target for effectively overcoming CCF and erection rehabilitation in neurogenic ED.

New uses for an old technique: live imaging on the slice organ culture to study reproductive processes†.

Reproductive processes are dynamic and involve extensive morphological remodeling and cell-cell interactions. Live imaging of organs enhances our understanding of how biological processes occur in real time. Slice culture is a type of organ culture where thick slices are collected from an organ and cultured for several days. Slice culture is a useful and easy-to-implement technique for live imaging of reproductive events at cellular resolution. Here we describe a pipeline of live imaging on slice culture to visualize the process of urethra closure in mouse embryonic penis as a proof of principle. In combination with genetic reporter mice, nuclear stains, and exposure experiments, we demonstrate the feasibility of slice culture on a reproductive organ. We also provide a step-by-step protocol and troubleshooting guide to facilitate the adoption of slice culture with live imaging in other reproductive organs. Lastly, we discuss potential utilities and experiments that could be implemented with slice culture in reproductive sciences.

Insertive condom-protected and condomless vaginal sex both have a profound impact on the penile immune correlates of HIV susceptibility.

The penis is the primary site of HIV acquisition in heterosexual men. Elevated penile inflammatory cytokines increase sexual acquisition risk, and topically applied cytokines enhance foreskin HIV susceptibility in an explant model. However, the impact of penile-vaginal sex on these immune parameters is undefined. Heterosexual couples were recruited to the Sex, Couples and Science (SECS) Study, with the collection of penile swabs, semen, cervico-vaginal secretions, and blood after a period of abstinence, and repeated sampling up to 72 hours after either condomless (n = 30) or condom-protected (n = 8) penile-vaginal sex. Soluble immune parameters were quantified by multiplex immunoassay. Co-primary immune endpoints were penile levels of IL-8 and MIG, cytokines previously linked to penile HIV acquisition. One hour after sex there were dramatic increases in penile IL-8 and MIG levels, regardless of condom use, with a gradual return to baseline by 72 hours; similar patterns were observed for other chemoattractant chemokines. Penile cytokine changes were similar in circumcised and uncircumcised men, and repeated measures ANOVA and ANCOVA models demonstrated that the degree of change after condomless sex was explained by cytokine levels in their partners' cervico-vaginal secretions. This may have important implications for the biology of penile HIV acquisition.

Creation of a Novel Classification System (PTNM) for Peyronie's Disease and Penile Curvature Using Evidence-Based Criteria.

PURPOSE: Our goal was to identify new Peyronie's disease (PD) subtypes, non-PD penile curvature classifications, and define active (acute) vs stable (chronic) phases of disease using evidence-based analyses. MATERIALS AND METHODS: A retrospective review was performed of 1098 men who presented with penile deformity, including subjective standardized and nonstandardized questionnaires and objective measures. A second cohort of 719 men who were sent a mailed survey was also utilized for the relapsing/remitting subtype. Statistical analyses were performed to identify clusters of disease characteristics representative of distinct PD and non-PD categorizations, including sensitivity/specificity analyses and subtype comparisons. RESULTS: Comparative analyses identified 4 distinct subtypes of PD: (1) classical and nonclassical, (2) calcifying-moderate/severe calcification, (3) progressive-subjective worsening following disease onset, and (4) relapsing/remitting-reactivation following ≥ 6 months of stability. Additional, non-PD categorizations included congenital (lifelong), maturational (developed around puberty), and trauma induced. Statistical analyses demonstrated unique profiles among each category. Penile pain was not found to be a reliable predictor for disease progression or stability. Stable phase disease (historically "chronic") was variably defined by subtype: classical (≥3 months); progressive, calcifying, or trauma induced (≥12 months + ≥3 months stable OR ≥6 months stable). Similarly, PD subtypes may be assigned at ≥ 3 months following disease onset. A PTNM staging system is proposed to help communicate disease states, in which P = PD component (Ca-calcifying, Cl-classical, P-progressive, R-relapsing/remitting, U-undifferentiated), T = trauma component (0-absent, 1-present), N = non-PD component (C-congenital, M-maturational, U-undifferentiated), and M = mode (0-stable, 1-active); for example, PClT1N0M0 = stable classical PD with prior trauma. CONCLUSIONS: The current study provides an evidence-based proposal for the establishment of new PD subtypes and non-PD curvature categorizations as well as a standardized definition for active vs stable phases of disease.

Neurovascular anatomy of the developing human fetal penis and clitoris.

The human penile and clitoral development begins from a morphologically indifferent genital tubercle. Under the influence of androgen, the genital tubercle forms the penis by forming a tubular urethra within the penile shaft. Without the effect of the androgen, the genital tubercle differentiates into the clitoris, and a lack of formation of the urethra within the clitoris is observed. Even though there are similarities during the development of the glans penis and glans clitoris, the complex canalization occurring along the penile shaft eventually leads to a morphological difference between the penis and clitoris. Based on the morphological differences, the main goal of this study was to define the vascular and neuronal anatomy of the developing penis and clitoris between 8 and 12 weeks of gestation using laser scanning confocal microscopy. Our results demonstrated there is a co-expression of CD31, which is an endothelial cell marker, and PGP9.5, which is a neuronal marker in the penis where the fusion is actively occurring at the ventral shaft. We also identified a unique anatomical structure for the first time, the clitoral ridge, which is a fetal structure running along the clitoral shaft in the vestibular groove. Contrary to previous anatomical findings which indicate that the neurovascular distribution in the developing penis and clitoris is similar, in this study, laser scanning confocal microscopy enabled us to demonstrate finer differences in the neurovascular anatomy between the penis and clitoris.

Intravenously engrafted human multilineage-differentiating stress-enduring (Muse) cells rescue erectile function after rat cavernous nerve injury.

OBJECTIVE: To evaluate the effect of intravenous administration of human multilineage-differentiating stress-enduring (Muse) cells on rat postoperative erectile dysfunction (ED) with cavernous nerve (CN) injury without an immunosuppressant. MATERIALS AND METHODS: Male Sprague-Dawley rats were randomised into three groups after CN crush injury. Either human-Muse cells, non-Muse mesenchymal stem cells (MSCs) (both 1.0 × 105 cells), or vehicle was infused intravenously at 3 h after CN injury without immunosuppressant. Erectile function was assessed by measuring intracavernous pressure (ICP) and arterial pressure (AP) during pelvic nerve electrostimulation 28 days after surgery. At 48 h and 28 days after intravenous infusion of Muse cells, the homing of Muse cells and non-Muse MSCs was evaluated in the major pelvic ganglion (MPG) after CN injury. In addition, expressions of C-X-C motif chemokine ligand (Cxcl12) and glial cell line-derived neurotrophic factor (Gdnf) in the MPG were examined by real-time polymerase chain reaction. Statistical analyses and comparisons among groups were performed using one-way analysis of variance followed by the Tukey test for parametric data and Kruskal-Wallis test followed by the Dunn-Bonferroni test for non-parametric data. RESULTS: The mean (SEM) ICP/AP values at 28 days were 0.51 (0.02) in the Muse cell group, 0.37 (0.03) in the non-Muse MSC group, and 0.36 (0.04) in the vehicle group, showing a significant positive response in the Muse cell group compared with the non-Muse and vehicle groups (P = 0.013 and P = 0.010, respectively). In the MPG, Muse cells were observed to be engrafted at 48 h and expressed Schwann cell markers S100 (~46%) and glial fibrillary acidic protein (~24%) at 28 days, while non-Muse MSCs were basically not engrafted at 48 h. Higher gene expression of Cxcl12 (P = 0.048) and Gdnf (P = 0.040) was found in the MPG of the Muse group than in the vehicle group 48 h after infusion. CONCLUSION: Intravenously engrafted human Muse cells recovered rat erectile function after CN injury in a rat model possibly by upregulating Cxcl12 and Gdnf.

Cosmetic penile enhancement procedures: an SMSNA position statement.

BACKGROUND: Penile cosmetic enhancement procedures have been performed for many years with varying success. However, they have historically been relegated to niche areas of sexual medicine, with limited data, and have not achieved mainstream adoption. More recently, the topic has been increasingly discussed within academic congresses due to availability of novel techniques, therapies, and procedures. Given their distinctive nature, the Sexual Medicine Society of North America (SMSNA) felt that it was pertinent to develop formal position statements to help guide both patients and sexual medicine providers on the current state of the scientific literature and to give recommendations for future research. AIM: The study sought to provide an evidence-based set of recommendations for injection and surgical procedures designed to lengthen, augment, or otherwise cosmetically enhance the penis. METHODS: A review was performed of all scientific literature listed in PubMed from inception through December 2023 relating to penile cosmetic enhancement procedures. Only invasive (injection/surgery) therapies were included due to their distinct risk-benefit profile compared with more conservative treatments (eg, vacuum erection devices, penile traction devices). Similar therapies were categorized, with pertinent data summarized and used to help create relevant position statements. All statements were expert opinion only and were based on analyses of the potential risks and benefits of the specific therapies. OUTCOMES: A total of 6 position statements were issued relating to 5 distinct sexual medicine cosmetic enhancement procedures. RESULTS: A consensus opinion was reached by SMSNA leadership on the state of injection/surgical penile cosmetic enhancement procedures as of 2024. Key topic areas addressed included injectable soft tissue fillers, suspensory ligament division, graft-and-flap procedures, silicone sleeve implants, and sliding/slicing techniques. Distinct recommendations were tailored to each therapy and were based solely on the current state of the literature. It is anticipated that future studies will further inform position statements and will lead to ongoing modifications. CLINICAL IMPLICATIONS: The current position statements provide both patients and clinicians evidence-based, expert recommendations on best practices relating to penile cosmetic enhancement procedures. STRENGTHS AND LIMITATIONS: Strengths include the use of an expert panel of sexual medicine clinicians, consensus design, and summary of existing literature. Limitations include expert opinion and limited research on the topic. CONCLUSION: The current SMSNA position statements provide evidence-based, consensus opinions on the appropriate role for penile augmentation and cosmetic procedures in 2024.

Extratunical grafting for minimally invasive management of complex Peyronie's disease deformities.

BACKGROUND: Penile deformities due to Peyronie's Disease (PD) often significantly impair men's sexual health and quality of life. AIM: In this article we discuss the extratunical graft (ETG) procedure as a management strategy for PD patients with hourglass or indent penile deformities. METHODS: We compiled descriptions of surgical techniques and performed a review of the literature regarding ETG for PD. OUTCOMES: The ETG procedure appears to have promising results in the management of indent/hourglass deformity of PD. RESULTS: The findings of this review of the literature demonstrate that ETG is a safe and effective reconstructive technique for penile deformity with minimal side effects. CLINICAL IMPLICATIONS: We recommend utilizing ETG with or without plication for PD patients with indent or hourglass deformities. STRENGTHS AND LIMITATIONS: Strengths of ETG are the improvement in patients with tunical indents and hourglass deformities secondary to PD. Additionally, patients who underwent ETG maintained sexual function given no significant change in penile length and intact erectile function. Limitations, however, are that the procedure is relatively new, and data are limited to small cohorts. CONCLUSION: The ETG procedure is a safe and effective for management of complex PD in the short- and intermediate-term follow-up cohort.

Outcomes of collagenase Clostridium histolyticum in men with ventral curvatures: an updated series.

BACKGROUND: The efficacy and safety of collagenase Clostridium histolyticum (CCH) have been demonstrated in the treatment of men with Peyronie's disease (PD); however, the pivotal clinical trials excluded men with ventral penile curvature. AIM: The study sought to evaluate outcomes of CCH treatment in men with ventral curvatures secondary to PD. METHODS: Men with PD treated with CCH were identified from a prospective database. Patients received up to 4 series of CCH injections using a progressively modified protocol over time. Results were compared between those with baseline ventral vs nonventral penile curvatures. OUTCOMES: Changes in penile curvature, Peyronie's Disease Questionnaire scores, International Index of Erectile Function scores, nonstandardized assessments, and adverse events. RESULTS: A total of 560 men with PD (85 ventral curvature, 475 nonventral curvature) were included in the analysis. Baseline median curvature was 60.0° (interquartile range, 48.8°-75.0°) in the ventral cohort and 65.0° (interquartile range, 45.0°-80.0°) in the nonventral cohort. Median change from baseline penile curvature was -25.0° in the ventral cohort vs -24.0° in the nonventral cohort (P = .08, between-group comparison), which corresponded to curvature reductions of 44.7% and 33.6%, respectively (P = .03). In the subset of patients who completed CCH treatment (ie, received 8 injections or discontinued early because of patient satisfaction with curvature reduction), median change from baseline was -35.0° in the ventral cohort vs -25.0° in the nonventral cohort (P < .05); median percent improvement was 48.3% and 37.5%, respectively (P = .11). Median change from baseline in Peyronie's Disease Questionnaire and International Index of Erectile Function domain scores and adverse events were similar between cohorts, with the exception of possibly higher hematoma rates in the nonventral group (50% vs 37%; P = .05). No urethral injuries were sustained in either cohort. CLINICAL IMPLICATIONS: Data support the use of CCH for the treatment of ventral as well as nonventral penile curvatures in men with PD. STRENGTHS AND LIMITATIONS: Study strengths are the inclusion of a general clinical population of men with PD, the prospective design, and the relatively large series of men with ventral curvature. Limitations include the single-center and observational nature of the study. CONCLUSION: CCH was safe and effective in the treatment of both ventral and nonventral penile curvatures in men with PD.

Clinical outcomes of the Burnett "snake" maneuver shunt modification for ischemic priapism.

BACKGROUND: Major ischemic priapism (IP) is defined as a persistent penile erection for >4 hours. IP may cause serious complications, especially if prompt resolution is not achieved. Therefore, selecting the most effective and usable shunt technique is crucial in IP cases that are refractory to medical therapy. AIM: To compare the effectiveness and complication risks of distal corporoglanular shunt procedures with and without the Burnett "snake" maneuver. METHODS: We conducted a retrospective study of patients who presented with IP and underwent surgical treatment at our institution between 2005 and 2021. The patients were categorized into 2 groups: group 1 (n = 26) underwent distal shunt + Burnett snake maneuver, and group 2 (n = 56) underwent distal shunt-only. Clinical history, parameters of IP, details of medical and surgical treatments, and follow-up information were evaluated. OUTCOMES: Outcomes included differences in IP resolution and recurrence, functional erections, and complications between corporoglanular shunt procedures with and without the Burnett snake maneuver. RESULTS: In group 1, 24 of 26 patients (92.3%) experienced priapism resolution with a single surgical intervention, while this outcome was observed in 30 of 56 patients (53.6%) in group 2 (P < .001). Notably, priapism recurrence was significantly lower in group 1, occurring in 1 of 24 patients (4.2%), as opposed to 8 of 30 patients (26.6%) in group 2 (P < .001). Of the patients with documented sexual function status at follow-up, functional erections (capable of penetration with or without phosphodiesterase 5 inhibitors) were noted in 6 of 14 patients (42.8%) in group 1 and 13 of 26 patients (50%) in group 2 (P = .66). CLINICAL IMPLICATIONS: This study provides valuable insights regarding technical aspects of distal shunt procedures with and without the Burnett snake maneuver for treating major IP episodes. These results can help surgeons with clinical decision making for patients who present with IP. STRENGTH AND LIMITATIONS: Limitations include the single-site retrospective design with potential selection bias, inaccuracies in medical record data, challenges in controlling confounding variables, and the lack of validated questionnaire scores for erectile function evaluation. CONCLUSION: Our study demonstrates that modifying distal shunt procedures using the Burnett snake maneuver significantly improves priapism resolution and effectively prevents further priapism episodes without introducing additional complications or erectile function loss, thereby distinguishing it from distal shunt-only procedures.

Glans penis volume is associated with lifelong premature ejaculation.

BACKGROUND: Although premature ejaculation (PE) is the most common male sexual dysfunction, the underlying mechanisms are not fully understood. AIM: The study sought to evaluate the possible associations among glans penis volume and tissue stiffness measured using penile ultrasonography and penile shear wave elastography (SWE) with PE. METHODS: Men 18 to 65 years of age with normal International Index of Erectile Function scores (>25) and who were diagnosed with PE between June 2021 and June 2022 were enrolled. The Premature Ejaculation Diagnostic Tool score and intravaginal ejaculation latency times were recorded. Healthy volunteers constituted the control group. The study group was divided into lifelong PE (LLPE) and acquired PE (AqPE) subgroups. In all groups, the glans penis volume was measured via penile ultrasonography and tissue stiffness of the glans penis, penile frenulum, postcircumcision mucosal cuff, and penile shaft were measured via SWE. The findings of the groups were compared using appropriate statistical methods. OUTCOMES: The outcomes included ultrasonographic and elastographic measurements of the glans penis. RESULTS: Data on 140 men, including 70 PE patients and 70 healthy volunteers, were evaluated. Of the patients, 20 had LLPE and 50 had AqPE. The median glans penis volume was significantly greater in the LLPE group (14.1 [range, 6.6-19] mm3) compared with the AqPE group (11.7 [range, 5.1-27] mm3) and control group (11.4 [range, 6.1-32] mm3) (P = .03). According to the Youden index, the best cutoff value for glans penis volume in LLPE compared with non-LLPE (AqPE + control) was 12.65 mm3 (area under the curve, 0.684; 95% confidence interval, 0.556-0.812; P = .009). The risk of having LLPE in those with a glans penis volume ≥12.65 mm3 was 3.326 (95% confidence interval, 1.234-8.965) times higher than the non-LLPE group (P = .014). There were no significant differences between the groups in the SWE evaluation of glans penis, penile frenulum, mucosal cuff, and penile shaft tissue stiffness. CLINICAL IMPLICATIONS: The high incidence of PE in those with high glans penis volume may make glans penis volume a predictor for the development of LLPE. STRENGTHS AND LIMITATIONS: This was the first study to show that PE is more common in individuals with a high glans penis volume. It was also the first to perform a penile elastographic evaluation in patients with PE. The most important limitation was that we did not evaluate glans penile nerve function with a test, but rather we made an indirect inference about the density of free nerve endings based on increased glans penile volume. CONCLUSION: Glans penis volume was a significant predictor for LLPE. However, there are no associations between PE and the glans penis, postcircumcision mucosal cuff, penile frenulum, or penile shaft tissue stiffness and development.

Efficient use of penile Doppler ultrasound for investigating men with erectile dysfunction.

BACKGROUND: Vasculogenic erectile dysfunction is the most common type of erectile dysfunction, and penile Doppler ultrasound (PDUS) is a useful tool to assess erectile hemodynamics in the clinician's effort to discuss prognosis and management strategies with the patient. AIM: We herein describe the PDUS protocol used at our center, including indications, technique, and data interpretation. METHODS: We describe our institutional experience with PDUS and discuss it in the context of a contemporary review of the literature for this investigation. OUTCOME: Our institutional PDUS protocol. RESULTS: To perform PDUS properly, adequate training, equipment, setting, technique, and interpretation are critical. The accuracy of PDUS is entirely predicated on achieving complete cavernosal smooth muscle relaxation. A redosing protocol optimizes the reliability and reproducibility of the hemodynamic data acquired during PDUS. A rigidity-based assessment is performed, and patients are scanned according to the erection rigidity achieved (full hardness) or by administration of maximum dose of the vasoactive agent. Peak systolic velocity is considered a measure of arterial inflow (normal, >30 cm/s), while end diastolic velocity evaluates the veno-occlusive mechanism (normal, <5 cm/s). After the procedure, the patient is evaluated to confirm detumescence. If the patient has a persistent penetration rigidity erection, intracavernosal phenylephrine is administered; however, if detumescence is not achieved with intracavernosal phenylephrine injections alone, corporal aspiration is potentially performed. CONCLUSION: PDUS is a valuable minimally invasive tool for erectile hemodynamics assessment and an accurate assessment of such, provided that complete cavernosal smooth muscle relaxation is achieved.

Double distal corporal anchoring stitch for lateral penile implant cylinder extrusion.

BACKGROUND: The ventral and distal aspects of the corpora cavernosa are the thinnest, increasing the likelihood of cylinder extrusion or crossover complications pertaining to inflatable penile prosthesis procedures. A double distal corporal anchoring double stitch can be used to robustly secure impending lateral extrusions and crossovers of implant cylinders. It is a novel, effective corrective measure for the uncommon complication of migrated cylinders in inflatable penile prosthesis placement. AIM: To describe the surgical indications and technique for the double distal corporal anchoring fixation stitch for lateral penile implant cylinder extrusion. METHODS: We discuss a double-stitch technique that is performed following corporoplasty and capsulotomy. A lateral incision is made subcoronally on the affected side to identify the crossover or lateral extrusion. The cylinder is repositioned properly within the native corpora to prevent further cylinder migration. Two 2-0 Ethibond sutures are threaded through the distal cylinder eyelet, and each suture is delivered through the glans with a Keith needle and tied off. An incision is made in the glans, and 1 arm of each suture is tied with the other to create a bridge between the sutures that can be positioned deep within the skin of the glans. OUTCOMES: Over the past 4 years, 66 patients with lateral cylinder extrusion underwent the double distal corporal anchoring fixation stitch procedure, with overall improved satisfaction (97%). Only 2 patients had surgical complications. One patient experienced repeated lateral extrusion of the penile implant cylinders 6 weeks following the double-anchoring stitches procedure. The second patient developed a painful suture granuloma that necessitated excision, which resolved this issue, and the penile implant cylinder remained in the proper position over a year later. CLINICAL IMPLICATIONS: This technique ensures the secure fixation of the affected cylinders in the surgical capsule by creating a bridge between 2 sutures holding each repositioned cylinder in place, and the ensuing fibrotic reaction helps to fixate the extruded cylinder within the midglandular tissue. STRENGTH AND LIMITATIONS: This surgical technique describes the double distal corporal anchoring stitch for lateral penile implant cylinder extrusion. Further studies are warranted to validate long-term outcomes and satisfaction. CONCLUSION: The double distal corporal anchoring fixation stitch is a safe and efficacious method to secure cylinders in the proper surgical capsule during revision procedures to correct distal crossovers or laterally extruded penile prosthesis implants.

Clinical efficacy and safety of hyaluronic acid gel injection in the glans penis for treatment of premature ejaculation: systematic review and meta-analysis.

BACKGROUND: In recent years, there has been growing interest in the use of hyaluronic acid (HA) for the treatment of premature ejaculation (PE). The efficacy of this treatment is quite controversial. AIM: This study intended to evaluate the efficacy and safety of glans penis augmentation with HA gel for PE. METHODS: This systematic review includes randomized controlled trials (RCTs), primary clinical trials, prospective and retrospective studies, case series, and case reports. Searches in Embase, PubMed, Cochrane, Web of Knowledge, and ClinicalTrials.gov were performed blindly by 2 reviewers. OUTCOMES: Intravaginal ejaculation latency time (IELT), questionnaires about PE, glans circumference (millimeters), and adverse events. RESULTS: Thirteen studies were included in the evaluation: 4 RCTs, 8 prospective observational studies, and 1 restrospective study. The number of patients who received HA gel on the glans penis was 706. According to the results of 2 placebo-controlled RCTs, HA gel treatment significantly improved IELT at the end of the first month (mean difference [MD], 65.44 seconds). In the first month after the HA gel injection procedure, IELT increased vs before the procedure (MD, 176.18 [95% CI, 146.89-205.48]; P < .001, I2 = 83%). When the IELT values ​​were compared at 6 months after HA gel application, IELT improved vs before the procedure (MD, 143.93 [95% CI, 124.78-163.09]; P < .001, I2 = 82). The glans circumference expanded by approximately 1.5 cm after the procedure (MD, 14.82 mm [95% CI, 12.75-16.90]; P < .001, I2 = 65%). When the side effect profile of other studies was examined, side effects were observed in 91 patients after HA gel injection applied to 598 patients (15.22%). Among these side effects, the most common were pain (n = 46, 7.69%), bulla/nodule formation (n = 25, 4.18%), and ecchymosis (n = 20, 3.34%). CONCLUSION: While HA shows promise as a therapeutic option for PE, ongoing research is essential to elucidate its clinical utility, mechanisms of action, and comparative efficacy.

BMP4 and GREM1 are targets of SHH signaling and downstream regulators of collagen in the penis.

BACKGROUND: Cavernous nerve (CN) injury, caused by prostatectomy and diabetes, initiates a remodeling process (smooth muscle apoptosis and increased collagen) in the corpora cavernosa of the penis of patients and animal models that is an underlying cause of erectile dysfunction (ED), and the Sonic hedgehog (SHH) pathway plays an essential role in the response of the penis to denervation, as collagen increases with SHH inhibition and decreases with SHH treatment. AIM: We examined if part of the mechanism of how SHH prevents penile remodeling and increased collagen with CN injury involves bone morphogenetic protein 4 (BMP4) and gremlin1 (GREM1) and examined the relationship between SHH, BMP4, GREM1, and collagen in penis of ED patients and rat models of CN injury, SHH inhibition, and SHH, BMP4, and GREM1 treatment. METHODS: Corpora cavernosa of Peyronie's disease (control), prostatectomy, and diabetic ED patients were obtained (N = 30). Adult Sprague Dawley rats (n = 90) underwent (1) CN crush (1-7 days) or sham surgery; (2) CN injury and BMP4, GREM1, or mouse serum albumin (control) treatment via Affi-Gel beads or peptide amphiphile (PA) for 14 days; (3) 5E1 SHH inhibitor, IgG, or phosphate-buffered saline (control) treatment for 2 to 4 days; or (4) CN crush with mouse serum albumin or SHH for 9 days. OUTCOMES: Immunohistochemical and Western analysis for BMP4 and GREM1, and collagen analysis by hydroxyproline and trichrome stain were performed. RESULTS: BMP4 and GREM1 proteins were identified in corpora cavernosa smooth muscle of prostatectomy, diabetic, and Peyronie's patients, and in rat smooth muscle, sympathetic nerve fibers, perineurium, blood vessels, and urethra. Collagen decreased 25.4% in rats with CN injury and BMP4 treatment (P = .02) and increased 61.3% with CN injury and GREM1 treatment (P = .005). Trichrome stain showed increased collagen in rats treated with GREM1. Western analysis identified increased BMP4 and GREM1 in corpora cavernosa of prostatectomy and diabetic patients, and after CN injury (1-2 days) in our rat model. Localization of BMP4 and GREM1 changed with SHH inhibition. SHH treatment increased the monomer form of BMP4 and GREM1, altering their range of signaling. CLINICAL IMPLICATIONS: A better understanding of penile remodeling and how fibrosis occurs with loss of innervation is essential for development of novel ED therapies. STRENGTHS AND LIMITATIONS: The relationship between SHH, BMP4, GREM1, and collagen is complex in the penis. CONCLUSION: BMP4 and GREM1 are downstream targets of SHH that impact collagen and may be useful in collaboration with SHH to prevent penile remodeling and ED.

Temporal gene signature of myofibroblast transformation in Peyronie's disease: first insights into the molecular mechanisms of irreversibility.

BACKGROUND: Transformation of resident fibroblasts to profibrotic myofibroblasts in the tunica albuginea is a critical step in the pathophysiology of Peyronie's disease (PD). We have previously shown that myofibroblasts do not revert to the fibroblast phenotype and we suggested that there is a point of no return at 36 hours after induction of the transformation. However, the molecular mechanisms that drive this proposed irreversibility are not known. AIM: Identify molecular pathways that drive the irreversibility of myofibroblast transformation by analyzing the expression of the genes involved in the process in a temporal fashion. METHODS: Human primary fibroblasts obtained from tunica albuginea of patients with Peyronie's disease were transformed to myofibroblasts using transforming growth factor beta 1 (TGF-ß1). The mRNA of the cells was collected at 0, 24, 36, 48, and 72 hours after stimulation with TGF-ß1 and then analyzed using a Nanostring nCounter Fibrosis panel. The gene expression results were analyzed using Reactome pathway analysis database and ANNi, a deep learning-based inference algorithm based on a swarm approach. OUTCOMES: The study outcome was the time course of changes in gene expression during transformation of PD-derived fibroblasts to myofibroblasts. RESULTS: The temporal analysis of the gene expression revealed that the majority of the changes at the gene expression level happened within the first 24 hours and remained so throughout the 72-hour period. At 36 hours, significant changes were observed in genes involved in MAPK-Hedgehog signaling pathways. CLINICAL TRANSLATION: This study highlights the importance of early intervention in clinical management of PD and the future potential of new drugs targeting the point of no return. STRENGTHS AND LIMITATIONS: The use of human primary cells and confirmation of results with further RNA analysis are the strengths of this study. The study was limited to 760 genes rather than the whole transcriptome. CONCLUSION: This study is to our knowledge the first analysis of temporal gene expression associated with the regulation of the transformation of resident fibroblasts to profibrotic myofibroblasts in PD. Further research is warranted to investigate the role of the MAPK-Hedgehog signaling pathways in reversibility of PD.

Heparin-binding epidermal growth factor-like growth factor improves erectile function in streptozotocin-induced diabetic mice.

BACKGROUND: Heparin-binding epidermal growth factor-like growth factor (HB-EGF) serves as a pro-angiogenic factor; however, there is to our knowledge currently no reported research on the relationship between HB-EGF and diabetic erectile dysfunction (ED). AIM: In this study we aimed to determine whether HB-EGF can improve the erectile function of streptozotocin-induced diabetic mice and to explore the related mechanisms. METHODS: Eight-week-old male C57BL/6 mice were used for diabetes induction. Diabetes mellitus (DM) was induced by low-dose injections of streptozotocin (50 mg/kg) for 5 consecutive days. Eight weeks after streptozotocin injections, DM was determined by measuring blood glucose and body weight. Diabetic mice were treated with two intracavernous administrations of phosphate-buffered saline (20 µL) or various doses of HB-EGF (days -3 and 0; 1, 5, and 10 µg in 20 µL of phosphate-buffered saline). The angiogenesis effect of HB-EGF was confirmed by tube formation and migration assays in mouse cavernous endothelial cells and mouse cavernous pericytes under high-glucose conditions. Erectile function was measured by electrical stimulation of the cavernous nerve, as well as histological examination and Western blot analysis for mechanism assessment. OUTCOMES: In vitro angiogenesis, cell proliferation, in vivo intracavernous pressure, neurovascular regeneration, cavernous permeability, and survival signaling were the outcomes measured. RESULTS: Expression of HB-EGF was reduced under diabetic conditions. Exogenous HB-EGF induced angiogenesis in mouse cavernous endothelial cells and mouse cavernous pericytes under high-glucose conditions. Erectile function was decreased in the DM group, whereas administration of HB-EGF resulted in a significant improvement of erectile function (91% of the age-matched control group) in association with increased neurovascular content, including cavernous endothelial cells, pericytes, and neuronal cells. Histological and Western blot analyses revealed a significant increase in the permeability of the corpus cavernosum in DM mice, which was attenuated by HB-EGF treatment. The protein expression of phospho-Akt Ser473 and phosphorylated endothelial nitric oxide synthase Ser1177 increased after HB-EGF treatment. CLINICAL IMPLICATIONS: The use of HB-EGF may be an effective strategy to treat ED associated with DM or other neurovascular diseases. STRENGTHS AND LIMITATIONS: Similarly to other pro-angiogenic factors, HB-EGF has dual roles in vascular and neuronal development. Our study focused on broadly evaluating the role of HB-EGF in diabetic ED. In view of the properties of HB-EGF as an angiogenic factor, its dose concentration should be strictly controlled to avoid potential side effects. CONCLUSION: In the diabetic ED mouse model in this study erectile function was improved by HB-EGF, which may provide new treatment strategies for patients with ED who do not respond to phosphodiesterase 5 Inhibitors.