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.

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.

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.

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.

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.

Is size in the eye of the beholder? Visual estimation of penis size among transgender and cisgender people and implications for genital gender-affirming surgery and sexual medicine.

BACKGROUND: Transgender men (TM) seeking gender-affirming phalloplasty and transgender women (TW) seeking vaginoplasty and desiring insertive intercourse must consider penis size. Evidence has shown that, at least among cisgender men (CM), penile dimensions tend to be poorly estimated. In transgender patients desiring gender-affirming surgery, inaccuracy in estimation of penis dimensions may lead to unnecessary morbidity: for TW, trauma to the neovagina; for TM with excess girth, an inability to insert. Studies on the accuracy with which transgender and cisgender patients estimate penis size are limited. AIM: To assess the degree of accuracy with which CM and CW, as well as TM and TW, visually estimate the size of the human penis, including length, width, and girth. METHODS: There were 142 participants included (25 TM, 47 TW, 30 CM, and 40 CW; net mean ± SD age, 36.6 ± 11.2 years). Participants were shown these models and asked to estimate length, width, and midshaft girth by visual inspection of 6 realistic models of a penis and scrotum of varying lengths and widths. We evaluated the accuracy of the visual measurements by comparing mean perceived dimensions with the actual dimensions of each model. OUTCOMES: We used a multivariate model of all 3 bias dimensions to test for differences in average bias among gender groups (CM, CW, TM, and TW). RESULTS: TM significantly overestimated length across the longest models. TW significantly overestimated length in the longer 3 models. All groups except for TM significantly underestimated girth in at least 1 model. No groups significantly underestimated width. CM, CW, and TM significantly overestimated width in all 6 models. CLINICAL IMPLICATIONS: When transgender patients use numbers to express penis size (either in neophallus or vaginal depth based on perceived partner size), the result is likely to be larger than expected. Use of realistic penis models as a decision-making tool may help manage patient expectations and surgery decision making preoperatively and improve postoperative patient satisfaction and safety. STRENGTHS AND LIMITATIONS: To our knowledge, this is the first study to assess visual estimation in penis size in TM and CM, as well as TW and CW. The penile models in our study were shown side by side and in the flaccid state despite having dimensions more consistent with an erect penis, which may have influenced estimations across all dimensions. CONCLUSION: Men and women (cisgender and transgender) tend to significantly overestimate penis length and width.

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.

Cldn4 overexpression promotes penile cavernous smooth muscle cell fibrotic response via the JNK signaling pathway.

BACKGROUND: Erectile dysfunction (ED), defined as the inability to achieve or maintain a penile erection sufficient to satisfy sexual behavior, is prevalent worldwide. AIM: Using previous research, bioinformatics, and experimental confirmation, we aimed to discover genes that contribute to ED through regulating hypoxia in corpus cavernosum smooth muscle cells (CCSMCs). METHODS: We used the Gene Expression Omnibus to acquire the sequencing data of the corpus cavernosum transcriptome for diabetic ED and nerve injury type ED rats. We intersected the common differentially expressed genes. Further verification was performed using single cell sequencing. Real-time quantitative polymerase chain reaction and immunofluorescence were used to investigate whether the differentially expressed genes are found in the corpus cavernosum. We used induced hypoxia to assess cell viability changes, and we developed a lentivirus overexpressing Cldn4 for in vitro and in vivo experiments to measure changes in JNK signaling, fibrosis, hypoxia, and erectile function. OUTCOMES: Our results indicate that targeting the JNK pathway and decreasing local hypoxia may be better options for therapeutic intervention to improve erectile function. RESULTS: We identified Cldn4 and found its expression increased in the corpora cavernosa of the 2 datasets. In addition, we found that hypoxia can increase the expression of Cldn4, activate the JNK signaling pathway, and exacerbate fibrosis in CCSMCs. Cldn4 overexpression in CCSMCs activated the JNK signaling pathway and increased fibrotic protein expression. Last, rat corpus cavernosum overexpressing Cldn4 activated the JNK signaling pathway, increased local fibrosis, and impaired erectile function. CLINICAL IMPLICATIONS: Through bioinformatics and in vitro and in vivo experiments, we found that Cldn4 has a negative effect on ED, and targeting Cldn4 may provide new ideas for ED treatment. STRENGTHS AND LIMITATIONS: Although we have identified Cldn4 as a potential target for ED treatment, we have only conducted preliminary validation on CCMSCs, and we still need to further validate in other cell lines. CONCLUSION: CCSMC hypoxia leads to increased Cldn4, in both nerve injury and diabetic ED rat models, and promotes fibrosis by activating the JNK signaling pathway.

Long-term outcomes after plaque excision grafting for Peyronie's disease and subanalysis of patients who undergo the procedure despite preoperative counseling against it.

BACKGROUND: Plaque excision and grafting (PEG) has been recommended for patients with Peyronie's disease (PD) with >60° curvature and/or hinge effect and strong preoperative erections, while placement of an inflatable penile prosthesis (IPP) is recommended when rigidity is suboptimal. Nevertheless, many patients counseled to undergo an IPP decline and insist on proceeding with PEG due to personal preference or desire to avoid an implant. AIM: We aim to review long-term outcomes in patients who underwent PEG for PD at our institution and investigate whether there is any difference in long-term outcomes in patients who undergo PEG despite a recommendation to undergo IPP. METHODS: We conducted a retrospective chart review from 2007 to 2021 on PEG surgery performed at a single tertiary care institution in patients ≥18 years old who had >3 months of follow-up. OUTCOMES: Postoperative information was gathered from the electronic medical record, including postoperative erectile function, patient satisfaction, and the ability to engage in penetrative sexual intercourse. RESULTS: An overall 251 patients underwent PEG with a median follow-up of 12 months (IQR, 6-54). Among these, 54 (22%) were initially advised to undergo IPP but elected for PEG. Patients who underwent PEG despite counseling to undergo IPP reported lower postoperative ability to engage in intercourse (51% vs 76%). Seven (13%) patients initially advised to undergo IPP eventually received an IPP, relative to 7 (4%) initially advised to undergo PEG. CLINICAL IMPLICATIONS: Thorough preoperative assessment of erectile function and penile deformity can guide clinician counseling and manage patient expectations during decision making between PEG surgery and IPP implantation for PD. STRENGTHS AND LIMITATIONS: Limitations of this study include its retrospective nature, high attrition to follow-up, and risk of recall and selection bias. This is a large study with a median follow-up of 12 months, with a high-volume single surgeon who treats patients in a specialized population of complex cases. CONCLUSION: Patients who were initially counseled to undergo IPP due to suboptimal erectile rigidity but elected for PEG had worse postoperative ability to engage in penetrative intercourse, and a higher proportion of these patients eventually received an IPP.

Delineating patient errors in an intracavernosal injection program.

BACKGROUND: Intracavernosal injection therapy (ICI) is a well-established therapeutic strategy for men with erectile dysfunction. Complications are often related to patient error when performong ICI. AIM: The objective of this study was to examine patient errors in an established patient training program for performing ICI and identify factors that could predict major errors. METHODS: Patients enrolled in our ICI program are trained on technical aspects, and dose titration is begun. Patients are given explicit instructions during training, both verbally and in written form. Records were reviewed for men using ICI for ≥6 months. Multivariable analysis was used to define predictors of major errors. OUTCOMES: Errors were listed as minor (zero-response injection, penile bruising, expired medication) and major (errors potentially leading to priapism: dose self-titration, double injecting). RESULTS: Overall, 1368 patients met the inclusion criteria and were included in the analysis. The mean patient age was 66 ± 22 (range 29-91) years. Regarding education, 41% of patients had graduate-level education, 48% had college education, and 11% high school education. Mean follow-up was 3.2 ± 7.6 (range 0.5-12) years. The agents used were trimix (62%), bimix (35%), papaverine (2%), and prostaglandin E1 monotherapy (1%). At least 1 error occurred during self-administration in 42% of patients during their time in the program. Errors included zero response to medication due to technical error (8% of patients), penile bruising (34%), use of an expired bottle (18%), self-titration (5%), and double injecting (4% of patients); 12% of men committed ≥1 error during their time in the program. On multivariable analysis, independent predictors of the occurrence of a major error included: young age, graduate-level education, and <12 months of injection use. CLINICAL IMPLICATIONS: To the best of our knowledge, this is the first reported study to investigate ICI errors and risk factors. The identification of factors predictive of major errors allows for more tailored and intensive training in this subset of patients. STRENGTHS AND LIMITATIONS: Strengths of this study include a large patient population (1386 men) with a considerable follow-up time. Additionally, the rigorous training, education, and monitoring of the participants, as well as the use of formal definitions, enhances the accuracy and reliability of the results. Despite the strengths of the study, recall bias may be a limitation concern. CONCLUSION: The majority of patients were error free, and the majority of the errors were minor in nature. Major errors occurred in <10% of patients. Younger age, graduate-level education, and less experience with ICI were independent predictors of major errors.

SHH regulates penile morphology and smooth muscle through a mechanism involving BMP4 and GREM1.

BACKGROUND: The cavernous nerve (CN) is frequently damaged in prostatectomy and diabetic patients with erectile dysfunction (ED), initiating changes in penile morphology including an acute and intense phase of apoptosis in penile smooth muscle and increased collagen, which alter penile architecture and make corpora cavernosa smooth muscle less able to relax in response to neurotransmitters, resulting in ED. AIM: Sonic hedgehog (SHH) is a critical regulator of penile smooth muscle, and SHH treatment suppresses penile remodeling after CN injury through an unknown mechanism; we examine if part of the mechanism of how SHH preserves smooth muscle after CN injury involves bone morphogenetic protein 4 (BMP4) and gremlin1 (GREM1). METHODS: Primary cultures of smooth muscle cells were established from prostatectomy, diabetic, hypertension and Peyronie's (control) (N = 18) patients. Cultures were characterized by ACTA2, CD31, P4HB, and nNOS immunohistochemical analysis. Patient smooth muscle cell growth was quantified in response to BMP4 and GREM1 treatment. Adult Sprague Dawley rats underwent 1 of 3 surgeries: (1) uninjured or CN-injured rats were treated with BMP4, GREM1, or mouse serum albumin (control) proteins via Affi-Gel beads (N = 16) or peptide amphiphile (PA) (N = 26) for 3 and 14 days, and trichrome stain was performed; (2) rats underwent sham (N = 3), CN injury (N = 9), or CN injury and SHH PA treatment for 1, 2, and 4 days (N = 9). OUTCOMES: Western analysis for BMP4 and GREM1 was performed; (3) rats were treated with 5E1 SHH inhibitor (N = 6) or IgG (control; N = 6) for 2 and 4 days, and BMP4 and GREM1 localization was examined. Statistics were performed by analysis of variance with Scheffé's post hoc test. RESULTS: BMP4 increased patient smooth muscle cell growth, and GREM1 decreased growth. In rats, BMP4 treatment via Affi-Gel beads and PA increased smooth muscle at 3 and 14 days of treatment. GREM1 treatment caused increased collagen and smooth muscle at 3 days, which switched to primarily collagen at 14 days. CN injury increased BMP4 and GREM1, while SHH PA altered Western band size, suggesting alternative cleavage and range of BMP4 and GREM1 signaling. SHH inhibition in rats increased BMP4 and GREM1 in fibroblasts. CLINICAL IMPLICATIONS: Understanding how SHH PA preserves and regenerates penile morphology after CN injury will aid development of ED therapies. STRENGTHS AND LIMITATIONS: SHH treatment alters BMP4 and GREM1 localization and range of signaling, which can affect penile morphology. CONCLUSION: Part of the mechanism of how SHH regulates corpora cavernosa smooth muscle involves BMP4 and GREM1.

Surgical management of complex curvature in Peyronie's disease.

PURPOSE: About 10% of Peyronie's patients are complex cases with severe curvature (>60 degrees), ventral plaque, multiplanar curvature, hour-glass/hinge deformity, notching deformity, and ossified plaque. In patients with complex Peyronie's disease (PD), different techniques (shortening procedures, lengthening procedures, and penile prosthesis implantation (IPP)) may be necessary to achieve successful result. This review aims to analyze the various surgical techniques employed in the management of Peyronie's disease, with a specific focus on patients with complex deformity. METHODS: Articles focusing on the surgical management of complex curvature in Peyronie's disease were searched in MEDLINE and PubMed published between 1990 and 2023. RESULTS: Shortening procedures are linked to penile shortening and are not recommended for complex cases such as notching, hour-glass deformity, or ossified plaque. Lengthening procedures are suitable for addressing complex curvatures without erectile dysfunction (ED) and are a more appropriate method for multiplanar curvatures. Penile prosthesis implantation (IPP), with or without additional procedures, is the gold standard for patients with ED and Peyronie's disease. IPP should also be the preferred option for cases of penile instability (hinge deformity) and has shown high satisfaction rates in all complex cases. CONCLUSION: While surgical interventions for complex curvature in Peyronie's disease carry inherent risks, careful patient selection, meticulous surgical techniques, and post-operative care can help minimize complications and maximize positive outcome.

Long-term experiences with high-energy shock wave therapy in the management chronic phase Peyronie's disease using two different electromagnetic lithotripters.

BACKGROUND: Extracorporeal shock wave lithotripsy represents one option for the non-surgical management of Peyronie's disease. Despite promising results, several questions are still pending. We want to present the long-term results of a retrospective study using high-energy extracorporeal shock wave lithotripsy. MATERIAL AND METHODS: We evaluated retrospectively 110 patients treated between 1996 and 2020 at the Department of Urology, SLK Kliniken Heilbronn for chronic phase Peyronie's disease using two electromagnetic lithotripters (Siemens Lithostar Plus Overhead Module, Siemens Lithoskop) applying high-energy shock waves under local anesthesia and sonographic or fluoroscopic control. A standardized questionnaire focused on the change in pain, curvature, sexual function and the need of penile surgery. RESULTS: In 85 of the 110 patients (mean age 54 years) we had sufficient data for evaluation. The median follow-up was 228 (6-288) months. There were no significant complications. Pain reduction was achieved in all patients, 65 (76%) patients were free of pain. Improvement of penile curvature was achieved in 43 patients (51%) ranging from 25% improvement (deflected angle < 30°) to 95% (angle 30-60°). 59 patients (69%) reported problems with sexual intercourse, 40 of those (68%) reported improvement. Only 9 (10.5%) patients underwent surgical correction. We did not observe any significant differences between both electromagnetic devices with stable long-term results. CONCLUSIONS: High-energy shock wave therapy delivered by two standard electromagnetic lithotripters is safe and efficient providing stable long-term results. In cases with significant plaque formation, the concept of high-energy ESWT should be considered in future studies.