Recent advances in stem cell therapy for erectile dysfunction: a narrative review.

INTRODUCTION: While phosphodiesterase type 5 inhibitors (PDE5is) and others are used to treat Erectile dysfunction (ED), many patients are either unresponsive or resistant to it. Stem cell therapy (SCT) is a promising alternative approach. Numerous preclinical trials have demonstrated improved erectile function in animal models using SCT, although the number of clinical trials investigating SCT for men with ED is limited. Nonetheless, findings from human clinical trials suggest that SCT may be a useful treatment option. AREAS COVERED: Biomedical literature, including PubMed, ClinicalTrials.gov, and European Union Clinical Trials Registry, were analyzed to summarize and synthesize information on stem cell therapy for ED in this narrative review. The achievements in preclinical and clinical evaluations are presented and critically analyzed. EXPERT OPINION: SCT has demonstrated some benefits in improving erectile function, while further studies are urgently needed. Such studies would provide valuable insights into the optimal use of stem cell therapy and its potential as a therapeutic option for ED. Taking advantage of different mechanisms of action involved in various regenerative therapies, combination therapies such as SCT and low-energy shock waves or platelet-rich plasma may provide a more effective therapy and warrant further research.

Effect of near-infrared laser treatment on improving erectile function in rats with diabetes mellitus.

BACKGROUND: Diabetes mellitus-induced erectile dysfunction is difficult to treat. The oxidative stress created by diabetes mellitus is a major cause of injuries to the corpus cavernosum, thereby resulting in erectile dysfunction. Near-infrared laser has already been shown to be effective in treating multiple brain disorders because of its antioxidative stress effect. OBJECTIVES: To investigate whether a near-infrared laser improves the erectile function of diabetes mellitus-induced erectile dysfunction rats through its antioxidative stress effect. MATERIALS AND METHODS: Knowing its advantage of reasonable deep tissue penetration and good photoactivation on mitochondria, a near-infrared laser with wavelength of 808 nm was used in the experiment. Since the internal and external corpus cavernosum were covered by different tissue layers, the laser penetration rates of the internal and external corpus cavernosum were measured separately. Different radiant exposure settings were applied: in the initial experiment, 40 male Sprague-Dawley rats were randomly assigned to five groups, normal controls, and streptozotocin-induced diabetes mellitus rats that 10 weeks later received various radiant exposures (J/cm2 ) from the near-infrared laser (DM0J(DM+NIR 0 J/cm2 ), DM1J, DM2J, and DM4J) in the subsequent 2 weeks. Erectile function was then assessed 1 week after near-infrared treatment. It was found that the initial radiant exposure setting was not optimal according to the Arndt-Schulz rule. We performed a second experiment using a different radiant exposure setting. Forty male rats were randomly divided into five groups (normal controls, DM0J, DM4J, DM8J, and DM16J), and the near-infrared laser was again applied according to the new setting, and erectile function was assessed as in the first experiment. Histologic, biochemical, and proteomic analyses were then conducted. RESULTS: Recovery of erectile function of varying degrees was observed in the near-infrared treatment groups, and radiant exposure of 4 J/cm2 achieved optimal results. The DM4J group showed improvement in mitochondrial function and morphology in diabetes mellitus rats, and it was found that oxidative stress levels were significantly reduced by near-infrared exposure. The tissue structure of the corpus cavernosum was also improved by near-infrared exposure. The proteomics analysis confirming multiple biologic processes were changed by diabetes mellitus and near-infrared. DISCUSSION AND CONCLUSION: Near-infrared laser activated mitochondria, improved oxidative stress, repaired the damage to penile corpus cavernosum tissue structures caused by diabetes mellitus, and improved erectile function in diabetes mellitus rats. These results thus raise the possibility that human patients with diabetes mellitus-induced erectile dysfunction may respond to near-infrared therapy in a manner that parallels the responses we observed in animal study.

Molecular Mechanism of Action of Low-Intensity Extracorporeal Shockwave Therapy for Regenerating Penile and Peripheral Nerves.

Sufficient functional repair of damaged peripheral nerves is a big clinical challenge in terms of long-lasting morbidity, disability, and economic costs. Nerve damage after radical prostatectomy is the most common cause of erectile dysfunction. In recent years, low-intensity extracorporeal shockwave therapy has been explored to improve the outcomes of peripheral nerve repair and regeneration. Research indicated that application of low-intensity extracorporeal shockwave therapy after nerve surgery promoted nerve regeneration and improved the functional outcomes, underlined the mechanisms related to increase of neurotrophic factors, Schwann cells activation, and cellular signaling activation for cell activation and mitosis induced by low-intensity extracorporeal shockwave therapy. We searched PubMed for articles related to research on these topics in both in vitro and in vivo animal models and found numerous studies suggesting that the application low-intensity extracorporeal shockwave therapy could be a novel treatment for erectile dysfunction induced by nerve injury and other disease related to nerve injury.

The Efficacy and Safety of Thrice vs Twice per Week Low-Intensity Pulsed Ultrasound Therapy for Erectile Dysfunction: A Randomized Clinical Trial.

BACKGROUND: A recent sham-controlled clinical study has shown that low-intensity pulsed ultrasound twice per week can safely and effectively treat patients with mild-to-moderate erectile dysfunction (ED). However, large-scale clinical trials are needed to verify its efficacy and safety and determine a reasonable treatment interval. AIM: To study whether low-intensity pulsed ultrasound therapy thrice per week is non-inferior to twice per week in patients with mild-to-moderate ED. METHODS: A randomized, open-label, parallel-group, non-inferiority clinical trial was conducted in 7 hospitals in China. A total of 323 patients with mild-to-moderate ED were randomized (1:1) into thrice per week (3/W) and twice per week (2/W) groups. Low-intensity pulsed ultrasound was applied on each side of the penis for 16 sessions. OUTCOMES: The primary outcome was response rate using the minimal clinically important difference in the International Index of Erectile Function (IIEF-EF) score at week 12. Secondary outcomes included Erection Hardness Score (EHS), Sexual Encounter Profile, Global Assessment Question, and Self Esteem and Relationship Questionnaire. RESULTS: Response rates in 3/W and 2/W groups were 62.0% and 62.5%, respectively. Treatment effect in the 3/W group was noninferior to that of the 2/W group, with rate difference lower bound of -0.01% [95% confidence interval -0.11 to 0.10%] within the acceptable margin (-14.0%). No significant difference was found among secondary outcomes. IIEF-EF score showed a significant increase from baseline in the 3/W group (16.8 to 20.7) and 2/W group (17.8 to 21.7), and the percentage of patients with EHS ≥3 increased in the 3/W (54.9% to 84.0%) and 2/W (59.5% to 83.5%) groups. There was no significant difference in response rate between the 2 groups after controlling for strata factors and homogeneous tests. No treatment-related adverse events were reported. CLINICAL IMPLICATIONS: Low-intensity pulsed ultrasound therapy displays similar efficacy and safety for mild-to-moderate ED when administered thrice or twice per week for 16 sessions. This study provides two options to suit patients' needs. STRENGTHS & LIMITATIONS: This is a large-sample, randomized, controlled, noninferiority trial study. Short-term follow-up and mostly younger patients are the main limitations. CONCLUSION: Low-intensity pulsed ultrasound therapy thrice and twice per week showed equivalent therapeutic effects and safety for mild-to-moderate ED in a young and generally healthy population. This therapy warrants further investigation of its potential value in rehabilitation of ED. Chen, H., Li Z., Li X., et al. The Efficacy and Safety of Thrice vs Twice per Week Low-Intensity Pulsed Ultrasound Therapy for Erectile Dysfunction: A Randomized Clinical Trial. J Sex Med 2022;19:1536-1545.

Single-cell transcriptome atlas of the human corpus cavernosum.

The corpus cavernosum is the most important structure for penile erection, and its dysfunction causes many physiological and psychological problems. However, its cellular heterogeneity and signalling networks at the molecular level are poorly understood because of limited access to samples. Here, we profile 64,993 human cavernosal single-cell transcriptomes from three males with normal erection and five organic erectile dysfunction patients. Cell communication analysis reveals that cavernosal fibroblasts are central to the paracrine signalling network and regulate microenvironmental homeostasis. Combining with immunohistochemical staining, we reveal the cellular heterogeneity and describe a detailed spatial distribution map for each fibroblast, smooth muscle and endothelial subcluster in the corpus cavernosum. Furthermore, comparative analysis and related functional experiments identify candidate regulatory signalling pathways in the pathological process. Our study provides an insight into the human corpus cavernosum microenvironment and a reference for potential erectile dysfunction therapies.

Microenergy acoustic pulse therapy restores function and structure of pelvic floor muscles after simulated birth injury.

Background: The mechanisms of the microenergy acoustic pulse (MAP) therapy on restoring structure and function of pelvic floor muscles (PFM) after simulated birth injury are not well understood. Methods: A total 24 female Sprague-Dawley rats were randomly grouped into sham control (sham), vaginal balloon dilation and ovariectomy (VBDO), VBDO + ß-aminopropionitrile (BAPN, an irreversible LOX inhibitor), and VBDO + BAPN and treated with MAP (n=6 in each group). The MAP therapy was administered 2 times per week for 4 weeks with 1-week washout, the functional and histological studies were conducted in all 24 rats. The viscoelastic behavior of the PFM, including iliococcygeus (IC) and pubococcygeus (PC), was examined with a biomechanical assay. The structure of the PFM was assessed by immunofluorescence and Masson's trichrome staining. Results: The leak point pressure (LPP) assay demonstrated that the MAP therapy group had higher LPPs compared to that of VBDO and BAPN groups. In the sham group, the muscular stiffness (K) of IC muscle was significantly higher than that of PC muscle while the pelvic floor muscle rebound activity (MRA) of PC muscle was stronger than that of IC muscle (291.26±45.33 and 241.18±14.23 N/cm2, respectively). Both VBDO and BAPN decreased the MRA and increased the K in both IC and PC. Histologic examination revealed increased fibrous tissue (collagen) and degeneration of muscle fibers in both VBDO and BAPN groups. MAP therapy significantly reduced the collagen content and improved the architecture of muscle fibers. Conclusions: MAP appears to restore the structure and function of PFM by regenerating muscular fibers and improving biomechanical properties in an animal model of simulated birth injury.

Enhanced Myogenesis by Silencing Myostatin with Nonviral Delivery of a dCas9 Ribonucleoprotein Complex.

Stress urinary incontinence (SUI) and pelvic floor disorder (PFD) are common conditions with limited treatment options in women worldwide. Regenerative therapy to restore urethral striated and pelvic floor muscles represents a valuable therapeutic approach. We aim to determine the CRISPR interference-mediated gene silencing effect of the nonviral delivery of nuclease-deactivated dCas9 ribonucleoprotein (RNP) complex on muscle regeneration at the cellular and molecular level. We designed four myostatin (MSTN)-targeting sgRNAs and transfected them into rat myoblast L6 cells together with the dCas9 protein. Myogenesis assay and immunofluorescence staining were performed to evaluate muscle differentiation, while CCK8 assay, cell cycle assay, and 5-ethynyl-2'-deoxyuridine staining were used to measure muscle proliferation. Reverse transcription-polymerase chain reaction and Western blotting were also performed to examine cellular signaling. Myogenic factors (including myosin heavy chain, MSTN, myocardin, and serum response factor) increased significantly after day 5 during myogenesis. MSTN was efficiently silenced after transfecting the dCas9 RNP complex, which significantly promoted more myotube formation and a higher fusion index for L6 cells. In cellular signaling, MSTN repression enhanced the expression of MyoG and MyoD, phosphorylation of Smad2, and the activity of Wnt1/GSK-3ß/ß-catenin pathway. Moreover, MSTN repression accelerated L6 cell growth with a higher cell proliferation index as well as a higher expression of cyclin D1 and cyclin E. Nonviral delivery of the dCas9 RNP complex significantly promoted myoblast differentiation and proliferation, providing a promising approach to improve muscle regeneration for SUI and PFD. Further characterization and validation of this approach in vivo are needed.

Microenergy acoustic pulse therapy restores urethral wall integrity and continence in a rat model of female stress incontinence.

OBJECTIVE: To determine the outcomes and mechanisms of microenergy acoustic pulse (MAP) therapy in an irreversible rat model of female stress urinary incontinence. MATERIALS AND METHODS: Twenty-four female Sprague-Dawley rats were randomly assigned into four groups: sham control (sham), vaginal balloon dilation and ovariectomy (VBDO), VBDO + ß-aminopropionitrile (BAPN), and VBDO + ß-aminopropionitrile treated with MAP (MAP). MAP therapy was administered twice per week for 4 weeks. After a 1-week washout period, all 24 rats were evaluated with functional and histological studies. The urethral vascular plexus was examined by immunofluorescence staining with antibodies against collagen IV and von Willebrand factor (vWF). The urethral smooth muscle stem/progenitor cells (uSMPCs) were isolated and functionally studied in vivo and in vitro. RESULTS: Functional study with leak point pressure (LPP) measurement showed that the MAP group had significantly higher LPPs compared to VBDO and BAPN groups. MAP ameliorated the decline in urethral wall thickness and increased the amount of extracellular matrix within the urethral wall, especially in the urethral and vaginal elastic fibers. MAP also improved the disruption of the urethral vascular plexus in the treated animals. In addition, MAP enhanced the regeneration of urethral and vaginal smooth muscle, and uSMPCs could be induced by MAP to differentiate into smooth muscle and neuron-like cells in vitro. CONCLUSION: MAP appears to restore urethral wall integrity by increasing muscle content in the urethra and the vagina and by improving the urethral vascular plexus and the extracellular matrix.

Microenergy acoustic pulses promotes muscle regeneration through in situ activation of muscle stem cells.

Microenergy acoustic pulses (MAP) is a modified low-intensity extracorporeal shock wave therapy that currently used for treating musculoskeletal disorders. However, its function on muscle regeneration after ischemia-reperfusion injury (IRI) remains unknown. This study aimed to explore the effect of MAP on muscle injury after IRI and its underlying mechanisms. Ten-week-old C57BL/6J mice underwent unilateral hindlimb IRI followed with or without MAP treatment. Wet weight of tibialis anterior muscles at both injury and contralateral sides were measured followed with histology analysis at 3 weeks after IRI. In in vitro study, the myoblasts, endothelial cells and fibro-adipogenic progenitors (FAP) were treated with MAP. Cell proliferation and differentiation were assessed, and related gene expressions were measured by real-time PCR. Our results showed that MAP significantly increased the muscle weight and centrally nucleated regenerating muscle fiber size along with a trend in activating satellite cells. In vitro data indicated that MAP promoted myoblast proliferation and differentiation and endothelial cells migration. MAP also induced FAP brown/beige adipogenesis, a promyogenic phenotype of FAPs. Our findings demonstrate the beneficial function of MAP in promoting muscle regeneration after IR injury by inducing muscle stem cells proliferation and differentiation.

Mineralized Peyronie's plaque has a phenotypic resemblance to bone.

Mineralized Peyronie's plaque (MPP) impairs penile function. The association, colocalization, and dynamic interplay between organic and inorganic constituents can provide insights into biomineralization of Peyronie's plaque. Human MPPs (n = 11) were surgically excised, and the organic and inorganic constituents were spatially mapped using multiple high-resolution imaging techniques. Multiscale image analyses resulted in spatial colocalization of elements within a highly porous material with heterogenous composition, lamellae, and osteocytic lacuna-like features with a morphological resemblance to bone. The lower (520 ±â€¯179 mg/cc) and higher (1024 ±â€¯155 mg/cc) mineral density regions were associated with higher (11%) and lower (7%) porosities in MPP. Energy dispersive X-ray and micro-X-ray fluorescent spectroscopic maps in the higher mineral density regions of MPP revealed higher counts of calcium (Ca) and phosphorus (P), and a Ca/P ratio of 1.48 ±â€¯0.06 similar to bone. More importantly, higher counts of zinc (Zn) were localized at the interface between softer (more organic to inorganic ratio) and harder (less organic to inorganic ratio) tissue regions of MPP and adjacent softer matrix, indicating the involvement of Zn-related proteins and/or pathways in the formation of MPP. In particular, dentin matrix protein-1 (DMP-1) was colocalized in a matrix rich in proteoglycans and collagen that contained osteocytic lacuna-like features. This combined materials science and biochemical with correlative microspectroscopic approach provided insights into the plausible cellular and biochemical pathways that incite mineralization of an existing fibrous Peyronie's plaque. STATEMENT OF SIGNIFICANCE: Aberrant human penile mineralization is known as mineralized Peyronie's plaque (MPP) and often results in a loss of form and function. This study focuses on investigating the spatial association of matrix proteins and elemental composition of MPP by colocalizing calcium, phosphorus, and trace metal zinc with dentin matrix protein 1 (DMP-1), acidic proteoglycans, and fibrillar collagen along with the cellular components using high resolution correlative microspectroscopy techniques. Spatial maps provided insights into cellular and biochemical pathways that incite mineralization of fibrous Peyronie's plaque in humans.

Penile Fractures: Evaluation and Management.

Penile fracture is a urologic injury with an etiology that varies based on the cultural milieu. Diagnosis can be made based on history and physical examination alone. Patients should be evaluated with RUG or cystoscopy when urethral injury is suspected. Ultrasound or MRI is a helpful adjunct when the diagnosis is unclear, and can assist in identifying the location of the rupture. Surgical management is favored over conservative measures to improve outcomes. Delayed surgical repair may not be inferior to immediate intervention.

Low-intensity pulsed ultrasound stimulates proliferation of stem/progenitor cells: what we need to know to translate basic science research into clinical applications.

Low-intensity pulsed ultrasound (LIPUS) is a promising therapy that has been increasingly explored in basic research and clinical applications. LIPUS is an appealing therapeutic option as it is a noninvasive treatment that has many advantages, including no risk of infection or tissue damage and no known adverse reactions. LIPUS has been shown to have many benefits including promotion of tissue healing, angiogenesis, and tissue regeneration; inhibition of inflammation and pain relief; and stimulation of cell proliferation and differentiation. The biophysical mechanisms of LIPUS remain unclear and the studies are ongoing. In recent years, more and more research has focused on the relationship between LIPUS and stem/progenitor cells. A comprehensive search of the PubMed and Embase databases to July 2020 was performed. LIPUS has many effects on stem cells. Studies show that LIPUS can stimulate stem cells in vitro; promote stem cell proliferation, differentiation, and migration; maintain stem cell activity; alleviate the problems of insufficient seed cell source, differentiation, and maturation; and circumvent the low efficiency of stem cell transplantation. The mechanisms involved in the effects of LIPUS are not fully understood, but the effects demonstrated in studies thus far have been favorable. Much additional research is needed before LIPUS can progress from basic science research to large-scale clinical dissemination and application.

Regenerating Urethral Striated Muscle by CRISPRi/dCas9-KRAB-Mediated Myostatin Silencing for Obesity-Associated Stress Urinary Incontinence.

Overweight females are prone to obesity-associated stress urinary incontinence (OA-SUI), and there are no definitive medical therapies for this common urologic condition. This study was designed to test the hypothesis that regenerative therapy to restore urethral striated muscle (stM) and pelvic floor muscles might represent a valuable therapeutic approach. For the in vitro experiment, single-guide RNAs targeting myostatin (MSTN) were used for CRISPRi/dCas9-Kruppel associated box (KRAB)-mediated gene silencing. For the in vivo experiment, a total of 14 female lean ZUC-Leprfa 186 and 14 fatty ZUC-Leprfa 185 rats were used as control and CRISPRi-MSTN treated groups, respectively. The results indicated that lentivirus-mediated expression of MSTN CRISPRi/dCas9-KRAB caused sustained downregulation of MSTN in rat L6 myoblast cells and significantly enhanced myogenesis in vitro. In vivo, the urethral sphincter injection of lentiviral-MSTN sgRNA and lentiviral-dCas9-KRAB significantly increased the leak point pressure, the thickness of the stM layer, the ratio of stM to smooth muscle, and the number of neuromuscular junctions. Downregulation of MSTN with CRISPRi/dCas9-KRAB-mediated gene silencing significantly enhanced myogenesis in vitro and in vivo. It also improved urethral continence in the OA-SUI rat model.

Molecular mechanism of action of low-intensity extracorporeal shockwave therapy for regenerating penile and peripheral nerves.

Sufficient functional repair of damaged peripheral nerves is a big clinical challenge in terms of long-lasting morbidity, disability, and economic costs. Nerve damage after radical prostatectomy is the most common cause of erectile dysfunction (ED). In recent years, low-intensity extracorporeal shockwave therapy (Li-ESWT) has been explored to improve the outcomes of peripheral nerve repair and regeneration. Research indicated that application of Li-ESWT after nerve surgery promoted nerve regeneration and improved the functional outcomes, underlined the mechanisms related to increase of neurotrophic factors, Schwann cells activation, and cellular signaling activation for cell activation and mitosis induced by Li-ESWT. We searched PubMed for articles related to research on these topics in both in vitro and in vivo animal models and found numerous studies suggesting that the application Li-ESWT could be a novel treatment for ED induced by nerve injury and other disease related to nerve injury.

Clinical Outcomes of Periprocedural Antithrombotic Therapy in Ischemic Priapism Management.

BACKGROUND: Priapism is a urologic emergency consisting of a painful erection lasting greater than 4 hours; antithrombotic therapy (ATT) have recently been recommended as an adjunct in the treatment of ischemic priapism. AIM: To determine the short- and long-term outcomes of periprocedural ATT in the management of acute ischemic priapism. METHODS: A retrospective review of patients seen at the University of California, San Francisco, from 2008 to 2019 was carried out to identify those evaluated for acute priapism. Information regarding duration of priapism, etiology, treatment, periprocedural and postprocedural ATT type and dose, and follow-up data was collected. OUTCOMES: ATT use was the exposure of interest; outcome variables included priapism resolution, repeat episodes, long-term complications, and follow-up. RESULTS: 70 patients with at least 1 detailed record of an acute priapism episode between 2008 and 2019 were identified. Of the 70 patients who underwent management for an acute episode of priapism, 59 (84%) received intracavernous injection of phenylephrine with or without corporal aspiration. Of the 4 patients who received ATT at the same time as intracavernous injection, none had additional priapism episodes. In the 55 patients who did not receive immediate ATT, 22 (40%) required at least 1 shunting procedure. The 9 patients who received ATT concurrently with shunting experienced less recurrence than the 13 patients who did not receive ATT (11% vs 69%, respectively P = .012). There were no significant differences in long-term erectile dysfunction (P = .627), fibrosis (P = .118), genitourinary pain (P = .474), and urinary issues (P = .158) between those who received ATT and those who did not. CLINICAL IMPLICATIONS: Our findings suggest that ATT has a role in preventing priapism recurrence; we observed that long-term repeat priapism episodes are less frequent in those who received periprocedural ATT compared with those who did not and that ATT may especially reduce recurrence in cases when shunting was required STRENGTHS & LIMITATIONS: This is the first study looking at the clinical outcomes of periprocedural ATT in the management of ischemic priapism. It is limited by the fact that it is a single-center study, types of ATT were heterogenous, and the exact timing of priapism management could not be measured for everyone. CONCLUSION: In spite of its limitations, these preliminary findings are promising and warrant further exploration of the use of ATT in the management of ischemic priapism. Ramstein JJ, Lee A, Cohen AJ, et al. Clinical Outcomes of Periprocedural Antithrombotic Therapy in Ischemic Priapism Management. J Sex Med 2020;17:2260-2266.

Exosome Released From Schwann Cells May Be Involved in Microenergy Acoustic Pulse-Associated Cavernous Nerve Regeneration.

BACKGROUND: Neurogenic erectile dysfunction (ED) is often refractory to treatment because of insufficient functional nerve recovery after injury or insult. Noninvasive mechano-biological intervention, such as microenergy acoustic pulse (MAP), low-intensity pulsed ultrasound, and low-intensity extracorporeal shockwave treatment, is an optimal approach to stimulate nerve regeneration. AIM: To establish a new model in vitro to simulate nerve injury in neurogenic ED and to explore the mechanisms of MAP in vitro. METHODS: Sprague-Dawley rats were used to isolate Schwann cells (SCs), major pelvic ganglion (MPG), and cavernous nerve with MPG (CN/MPG). SCs were then treated with MAP (0.033 mJ/mm2, 1 Hz, 100 pulses), and SC exosomes were isolated. The MPG and CN/MPG were treated with MAP (0.033 mJ/mm2, 1 Hz) at different dosages (25, 50, 100, 200, or 300 pulses) or exosomes derived from MAP-treated SCs in vitro. OUTCOMES: Neurite growth from the MPG fragments and CN was photographed and measured. Expression of neurotropic factors (brain-derived neurotrophic factor, nerve growth factor, and neurotrophin-3) was checked. RESULTS: Neurite outgrowth from MPG and CN/MPG was enhanced by MAP in a dosage response manner, peaking at 100 pulses. MAP promoted SC proliferation, neurotropic factor (brain-derived neurotrophic factor, nerve growth factor, and neurotrophin-3) expression, and exosome secretion. SC-derived exosomes significantly enhanced neurite outgrowth from MPG in vitro. CLINICAL IMPLICATIONS: MAP may have utility in the treatment of neurogenic ED by SC-derived exosomes. STRENGTH & LIMITATIONS: We confirmed that MAP enhances penile nerve regeneration through exsomes. Limitations of this study include that our study did not explore the exact mechanisms of how MAP increases SC exosome secretion nor whether MAP modulates the content of exosomes. CONCLUSION: This study revealed that neurite outgrowth from MPG was enhanced by MAP and by SC-derived exosomes which were isolated after MAP treatment. Our findings indicate that one mechanism by which MAP induces nerve regeneration is by stimulation of SCs to secrete exosomes. Peng D, Reed-Maldonado AB, Zhou F, et al. Exosome Released From Schwann Cells May Be Involved in Microenergy Acoustic Pulse-Associated Cavernous Nerve Regeneration. J Sex Med 2020;17:1618-1628.

Delayed Treatment With Low-intensity Extracorporeal Shock Wave Therapy in an Irreversible Rat Model of Stress Urinary Incontinence.

OBJECTIVE: To determine the outcomes and mechanisms of delayed low-intensity extracorporeal shock wave therapy (Li-ESWT) in a rat model of irreversible stress urinary incontinence (SUI). MATERIALS AND METHODS: Twenty-four female Sprague-Dawley rats were randomly assigned into 3 groups: sham control, vaginal balloon dilation + ß-aminopropionitrile (BAPN; SUI group), and vaginal balloon dilation + BAPN + treatment with Li-ESWT (SUI-Li-ESWT group). An irreversible SUI model was developed by inhibiting the urethral structural recovery with BAPN daily for 5 weeks. Thereafter, in the SUI-Li-ESWT group, Li-ESWT was administered twice per week for 2 weeks. After a 1-week washout, all 24 rats were evaluated with functional and histologic studies at 17 weeks of age. Endogenous progenitor cells were detected via the EdU-labeling method. RESULTS: Functional analysis with leak point pressure testing showed that the SUI-Li-ESWT group had significantly higher leak point pressures compared with untreated rats. Increased urethral and vaginal smooth and striated muscle content and increased thickness of the vaginal wall were noted in the SUI-Li-ESWT group. The SUI group had significantly decreased neuronal nitric oxide /tyrosine hydroxylase positive nerves ratio in the smooth muscle layers of the urethra, while the SUI-Li-ESWT group had neuronal nitric oxide/tyrosine hydroxylase+ nerves ratio similar to that of the control group. The continuality of urothelial cell lining was also improved in the SUI-Li-ESWT group. In addition, there were significantly increased EdU-positive cells in the SUI-Li-ESWT group. CONCLUSION: Li-ESWT appears to increase smooth muscle content in the urethra and the vagina, increase the thickness of urethral wall, improve striated muscle content and neuromuscular junctions, restore the integrity of the urothelium, and increase the number of EdU-retaining progenitor cells in the urethral wall.