Poly-L-lactic acid/gelatin electrospun membrane-loaded bone marrow-derived mesenchymal stem cells attenuate erectile dysfunction caused by cavernous nerve injury.

Radical prostatectomy (RP) can cause neurogenic erectile dysfunction (ED), which negatively affects the quality of life of patients with prostate cancer. Currently, there is a dearth of effective therapeutic strategies. Although stem cell therapy is promising, direct cell transplantation to injured cavernous nerves is constrained by poor cell colonization. In this study, poly-L-lactic acid (PLLA)/gelatin electrospun membranes (PGEM) were fabricated to load bone marrow-derived mesenchymal stem cells (BM-MSCs) as a patch to be placed on injured nerves to alleviate ED. This study aimed to establish a promising and innovative approach to mitigate neurogenic ED post-RP and lay the foundation for modifying surgical procedures. Electrospinning and molecular biotechnology were performed in vitro and in vivo, respectively. It was observed that PGEM enhanced the performance of BM-MSCs and Schwann cells due to their excellent mechanical properties and biocompatibility. The transplanted PGEM and loaded BM-MSCs synergistically improved bilateral cavernous nerve injury-related ED and the corresponding histopathological changes. Nevertheless, transplantation of BM-MSCs alone has been verified to be ineffective. Overall, PGEM can serve as an ideal carrier to supply a more suitable survival environment for BM-MSCs and Schwann cells, thereby promoting the recovery of injured cavernous nerves and erectile function.

Co-overexpression of VEGF and Smad7 improved the therapeutic effects of adipose-derived stem cells on neurogenic erectile dysfunction in the rat model.

Cavernous nerve injury is the main cause of erectile dysfunction (ED) after radical prostatectomy (RP). In our previous study, injection of adipose-derived stem cells (ADSCs) into the cavernosum can repair damaged cavernosum nerves and ED can be restored to a certain extent. In order to improve these therapeutic effects, we evaluated the efficacy of ADSCs co-modified with VEGF and Smad7 in a rat model. SD rats were randomly divided into six groups: a sham surgery group, and the five bilateral cavernous nerve injury (BCNI) groups were injected with ADSC or ADSCs genetically modified by VEGF (ADSC-V), Smad7 (ADSC-S), or VEGF&Smad7 (ADSC-V&S) or phosphate-buffered saline (PBS). The results indicated that the erectile function of the ADSC-V, ADSC-S, and ADSC-V&S groups was significantly recovered, and the erectile function of the ADSC-V&S group was more distinctly recovered as compared to the other groups. The same results are shown in the expression of neuronal nitric oxide synthase and the smooth muscle/collagen ratio of penile tissue comparing the ADSC-V&S group to the ADSC-V and ADSC-S group. These experimental data suggest that ADSCs co-overexpressed with VEGF and Smad7 can significantly improve erectile function after BCNI. This study provides new therapeutic thoughts for ED following RP.

Acetyl-L-carnitine improves erectile function in bilateral cavernous nerve injury rats via promoting cavernous nerve regeneration.

BACKGROUND: Neurogenic erectile dysfunction (NED) caused by cavernous nerve (CN) injury is a typical complication after pelvic surgery, which lacks efficient treatments. Acetyl-L-carnitine (ALCAR) has been proven to promote nerve repair. OBJECTIVES: To investigate the effect and potential mechanism of ALCAR in the treatment of NED. MATERIALS AND METHODS: Thirty-two rats were randomly divided into bilateral CN injury (BCNI) group, BCNI + lower-dose ALCAR (50 mg/kg/day) group, BCNI + higher-dose (100 mg/kg/day) group, and sham-operated group. Erectile function was assessed 14 days after daily intraperitoneal injection of ALCAR or placebo. The penile tissues were gathered for subsequent histological and molecular biological analysis. Rat Schwann cell (SC) line S16 was used to verify the mechanism of ALCAR in vitro. RESULTS: We found that the erectile function of the rats in the BCNI group was severely impaired, which was improved considerably in both BCNI+ALCAR-LD and BCNI+ALCAR-HD groups. Also, we observed decreased smooth muscle and increased collagen content in the corpus cavernosum in the BCNI group. The expressions of fibrosis markers transforming growth factor-beta (TGF-ß), connective tissue growth factor (CTGF), and Smad 2/3 were significantly up-regulated in the BCNI group. The above changes were alleviated after the administration of lower and higher-dose ALCAR. Meanwhile, the nitric oxide (NO)/cyclic guanosine monophosphate pathway (cGMP) was promoted and the Ras homolog gene family member A (RhoA)/Rho-associated protein kinase (ROCK) pathway was inhibited in the corpus cavernosum of BCNI rats after ALCAR treatment, accompanied by increased neuronal nitric oxide synthase (nNOS) and down-regulated tyrosine hydroxylase (TH). In vitro, ALCAR promoted the migration and proliferation of SC and increased the expression of 22-kD peripheral myelin protein and nerve growth factor (NGF). Further, rats treated with ALCAR had high expression of ATF3 and S100 in the distal nerve tissues of the CN extrusion site. DISCUSSION AND CONCLUSION: ALCAR could promote nerve repair and regeneration, inhibit penile fibrosis, and improve penile erection by promoting the proliferation and migration of SC and the secretion of NGF. Our study confirms that ALCAR may be a potential treatment strategy for NED.

Low-Intensity Electrostimulation Enhances Neuroregeneration and Improves Erectile Function in a Rat Model of Cavernous Nerve Injury.

BACKGROUND: Neurogenic erectile dysfunction (ED) following radical prostatectomy (RP) is a frequent complication often leading to erectile tissue remodeling and permanent ED. Low-intensity electrostimulation (LIES) has been shown to enhance peripheral nerve regeneration, however, its application on cavernous nerves (CN) has never been investigated. AIMS: To investigate whether LIES enhances CN regeneration, improves erectile function (EF) recovery, and prevents corpora cavernosal remodeling after CN injury, which is a principal factor for ED following RP. METHODS: Adult male Sprague-Dawley rats were divided into Sham, Bilateral Cavernous Nerve Injury (BCNI), and BCNI + LIES (1V, 0.1ms, 12Hz, 1h/day). After 7days, EF was assessed (ICP measurement). Penes and CN were collected for molecular analyses of TGF-ß1, Il-6, CRP, eNOS, ERK and AKT protein levels in corpus cavernosum (CC), and immunohistological analysis of DHE, total collagen and α-SMA in CC and S-100, Tub-III, DAPI, TUNEL, and nNOS in CN. OUTCOMES: Effects of LIES on EF, erectile tissue remodeling and CN structure. RESULTS: EF was decreased (P < .05) 7 days after BCNI and increased (P < .05) by LIES. Intracavernosal reactive oxygen species (DHE) was increased (P < .05) after BCNI and normalized by LIES. Protein expressions of TGF-ß1, IL-6, and CRP were increased in the penis (P < .05) after BCNI and normalized by LIES. The α-SMA and/or total collagen ratio was decreased (P < .05) after BCNI in the penis and normalized by LIES. Protein expression ratio of p-ERK/ERK and p-AKT/AKT did not change after BCNI but increased (P < .05) in LIES group. Myelination and number of nNOS positive cells in the CN were decreased (P < .05) after BCNI and normalized by LIES. The number of apoptotic nerve cells within the dorsal penile nerve was increased (P < .05) after BCNI and decreased (P < .05) by LIES compared to the BCNI group. There were no differences in eNOS expression in the penis between study groups. CLINICAL TRANSLATION: LIES may offer a potential new tool for penile rehabilitation and ED management following RP, potentially enhancing EF recovery and minimizing the side effects of this surgery. STRENGTHS & LIMITATIONS: This study provides evidence of the protective effect of LIES on EF and tissue remodeling following CN injury; nevertheless, this study has been conducted on animals and the translation to humans remains to be demonstrated. Further research to identify the underlying mechanisms of action is required. CONCLUSION: This study demonstrates that LIES of the CN after CN injury protects CN structure, enhances EF recovery, and prevents corpora cavernosal remodeling. Sturny M, Karakus S, Fraga-Silva R, et al. Low-Intensity Electrostimulation Enhances Neuroregeneration and Improves Erectile Function in a Rat Model of Cavernous Nerve Injury. J Sex Med 2022;19:686-696.

A Systematic Review of Penile Prosthesis Insertion in Patients With Spinal Cord Injury.

INTRODUCTION: A penile prosthesis (PP) may be inserted for erectile dysfunction (ED) and/or urinary management in men with spinal cord injury (SCI). This group of patients is considered high risk for complications due to their reduced mobility and sensation. OBJECTIVES: To identify the complication and satisfaction rates following PP insertion in patients with SCI. METHODS: A systematic review of the literature was performed according to the PRISMA checklist. The Medline/PubMed and EMBASE databases were searched up to July 27th 2021. Studies on men ≥18 years who had a PP inserted for ED secondary to SCI were included. Two reviewers independently screened all articles, assessed for risk of bias and performed data extraction. RESULTS: Eleven studies including 475 men with SCI were included for analysis. The overall complication rate was 4.2-61.1%. Specific complications included infection, 0-16%; erosion, 3.7-11.1% and mechanical failure, 0-16.7%. The explantation rate was 2.1-16.7% and the revision rate was 2.7-44.4%. Overall, 79.2-92.9% of men were satisfied with their PP and, 36-86.1% were having satisfactory sexual intercourse. In those who used the PP for urinary management ± ED, 86.5--92.8%% were satisfied. Men with SCI had higher rates of complications compared to those without SCI (infection, 2.1-9.1% vs non-SCI, 0.8-5.7%; erosion, 2.1-8.3% vs non-SCI, 0%; explanation, 2.1-8.3% vs non-SCI, 0.8-5.7%). CONCLUSION: PP is an option for SCI patients for the management of end-stage ED or urinary function, but the rate of infection, erosion and implant explantation is higher compared with men without SCI. Inflatable penile prosthesis (IPP) is the preferred PP due to the lower risk of erosion, however, they are prone to mechanical failure and require good hand dexterity. A thorough pre-operative counselling is essential. Pang KH, Muneer A, Alnajjar HM, et al. A Systematic Review of Penile Prosthesis Insertion in Patients With Spinal Cord Injury. Sex Med Rev 2022;10:461-470.

Neuroprotective effect of Hongjing I granules on erectile dysfunction in a rat model of bilateral cavernous nerve injury.

Neurogenic erectile dysfunction (NED) is an inevitable postoperative disease of cavernous nerve injury which will lead to various pathophysiological changes in the corpus cavernosum and dorsal penile nerve caused by radical prostatectomy (RP). Although serval years of clinical application of HJIG I granules (HJIG), an innovative formulation, has demonstrated its reliable clinical efficacy against NED, the mechanism of HJIG remains unclear. This study aimed to assess the neuroprotective effect of HJIG, to repair damaged nerves in a rat model of bilateral cavernous nerve injury (BCNI) in vivo and their effects on neurites of major pelvic ganglia (MPG) regeneration and Schwann cells (SCs) proliferation in vitro. Rats were divided into five groups randomly: normal control (NC), BCNI-induced ED model (M), M + low-dose HJIG (HL), M + medium-dose HJIG (HM), and M + high-dose HJIG (HH). All groups were treated with normal saline or the relevant drug for 28 consecutive days after a standard NED animal model. Our data revealed that administration of HJIG improved NED that was detected by intracavernous pressure (ICP) in a dose-dependent manner. The haematoxylin-eosin (HE) and Immunofluorescence (IF) staining demonstrated that HJIG ameliorate the shape of penis and induced the protein synthesis of GAP43, NF200, S100, and nNOS. NF200 and S100 level were also detected by western blotting. Moreover, HJIG (0.78 mg/mL) markedly increased SCs viability and promoted neurites regeneration of MPG. These findings provide new insights into the NED therapy by HJIG.

Neurogenic Sexual Dysfunction Treatment: A Systematic Review.

CONTEXT: The genesis of neurogenic sexual dysfunction (NSD) can be central, peripheral, or both. The correct stratification of the level of sexual dysfunction allows the clinician to choose the best type of treatment, in order to reduce sexual complaints. OBJECTIVE: The aim of our review is to focus on the management of NSD due to central nervous system disorders and peripheral neuropathy. EVIDENCE ACQUISITION: A systematic review of the English-language literature was completed until July 2019 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The following terms were included: [(neurogenic sexual dysfunction) OR neurogenic erectile dysfunction)] AND (treatment OR management). An Excel file was created respecting the following criteria: participants, interventions, comparators, outcomes, and study design (PICOS). EVIDENCE SYNTHESIS: Overall, from 505 identified records, 52 full-text articles were assessed for eligibility. Finally, 46 original researches were included in quantitative analysis. CONCLUSIONS: The phosphodiesterase type 5 inhibitors sildenafil, tadalafil, and vardenafil were proved to be effective and safe in first-line therapy of erectile dysfunction caused by neurogenic disorders. In addition, intracavernous injections of prostaglandin E1, papaverine, or phentolamine and vacuum systems have been a mainstay of second-line treatment for NSD, extremely successful in the spinal cord injury population. Surgical therapy via penile prosthesis implantation remains a viable alternative as a third-line approach and may also be utilised to assist men with bladder management, despite higher complication rates of infections. Despite poor evidence, a better understanding of female sexual dysfunction due to neurological complaints is needed, in order to find more efficacious therapies for intercourse and orgasmic phase. Further prospective studies are required to better clarify the more successful treatment in improving sexual function and quality of life of these patients. PATIENT SUMMARY: Management of neurogenic sexual dysfunction includes phosphodiesterase type 5 inhibitors, intracavernous injections/vacuum devices, and penile prosthesis implantation. Female sexual dysfunction due to neurological disease needs to be better investigated.

Erectile Dysfunction in Individuals with Neurologic Disability: A Hospital-based Cross-sectional Study.

OBJECTIVE: Neurogenic erectile dysfunction can be broadly defined as an inability to sustain or maintain a penile erection due to neurologic impairment. Sexual problems can occur due to any lesion affecting the central and peripheral nervous system. The aim of this study was to evaluate the prevalence and causes of erectile dysfunction in a group of hospital inpatients suffering from neurologic disorders. METHODS: Three-hundred and twenty six male patients admitted to the Neurorehabilitation Unit of IRCCS Centro Neurolesi "Bonino-Pulejo" in Messina Italy from March 2012 to June 2013 were screened for erectile dysfunction using the International Index of Erectile Function questionnaire. The patients who reported erectile dysfuntion underwent vascular, neurophysiological, and hormonal testing, and were divided into two groups according to their lesion sites: G1 (lesions above the S2-S4 center) and G2 (lesions below the S2-S4 center). RESULTS: Of the 326 admitted patients, 126 patients (38.6%), mean age of 54.56±11.74 years (age range 27-82 years), were affected by erectile dysfunction (i.e., scored ≤21). A statistically significant correlation between International Index of Erectile Function questionnaire scores and location of the neurologic lesions was observed in G2 (r=0.22) with an increased risk of erectile dysfuntion of around 2:1 (odds ratio=1.87) without influences related to aging. CONCLUSION: The occurence of erectile dysfunction is significantly more prevalent among neurologically disabled men, particularly those with lesions below S2-S4, than among men without neurologic disability. Considering the prevalence of erectile dysfunction among neurologically disabled men, sexual functioning should be regularly evaluated during acute and long-term rehabilitation, and any existing sexual dysfunction should be addressed in the treatment plan.

Novel therapeutic approach for neurogenic erectile dysfunction: effect of neurotrophic tyrosine kinase receptor type 1 monoclonal antibody.

BACKGROUND: Erectile dysfunction (ED) is a major health issue in aged populations, and neurogenic ED is particularly difficult to treat. Novel therapeutic approaches are needed for treatment of neurogenic ED of peripheral origin. OBJECTIVE: To investigate the therapeutic effects of a neurotrophic tyrosine kinase receptor type 1 monoclonal antibody (TrkA-mAb) on erectile function and sexual behavior in a rat model of cavernous nerve injury (CNI). DESIGN, SETTING, AND PARTICIPANTS: In one experiment, 84 male rats were randomly assigned to seven groups. The groups underwent either CNI or sham surgery, subsequent injection into the major pelvic ganglion (IMPG) of phosphate-buffered saline (PBS), an immunoglobulin G (IgG) control, or TrkA-mAb, and then intracavernosal (IC) injection of either PBS or varying TrkA-mAb concentrations immediately after surgery and then 1 wk later. Erectile function was assessed and histologic/molecular analyses were performed at 6 wk after surgery. In a second experiment, 36 male rats were randomly divided into three groups. The groups underwent CNI or sham surgery and then IC injection of PBS, IgG, or TrkA-mAb immediately after surgery and for 5 wk thereafter. At 6 wk after surgery, the performance of the rats in sexual behavior tests was videotaped. INTERVENTION: CNI or sham surgery; IMPG of PBS, IgG, or TrkA-mAb; IC injection of PBS or TrkA-mAb. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The intracavernous pressure response to cavernous nerve electrostimulation was measured and midpenile cross-sections were histologically examined. Western blotting (WB) of cavernous tissue protein was performed. Rats were assessed for chasing, mounting, intromission, and ejaculation behaviors during sexual behavior tests. The data were analyzed using one-way analysis of variance followed by the Tukey-Kramer t test. RESULTS AND LIMITATIONS: Recovery of erectile function of varying degrees was observed in the TrkA-mAb groups. TrkA-mAb treatment significantly suppressed tyrosine hydroxylase-positive nerve fibers in the corpus cavernosum and enhanced neuronal nitric oxide synthase-positive fibers in the dorsal nerve. The ratio of smooth muscle to collagen in the corpus cavernosum was significantly improved in TrkA-mAb treatment groups compared to PBS vehicle and IgG control groups. WB confirmed these biological changes. There was a nonsignificant increase in the average number of intromissions and ejaculations in the TrkA-mAb group. The study limitations include small sample size, variability in sexual behavior, lack of data on the neuromuscular mechanism involved, and lack of information of the role of neurotrophins or cytokines in regeneration. CONCLUSIONS: TrkA-mAb successfully inhibits sympathetic nerve regeneration, leads to parasympathetic nerve regeneration, and has therapeutic effects on ED and sexual behavior disorder in a rat model of CNI. PATIENT SUMMARY: This report provides strong evidence that a neurotrophic tyrosine kinase receptor type 1 monoclonal antibody (TrkA-mAb) inhibits sympathetic nerve regeneration, leads to parasympathetic nerve regeneration, and has therapeutic effects on erectile dysfunction and sexual behavior disorder in a rat model of cavernous nerve injury. The results raise the possibility that human patients with neurogenic erectile dysfunction may respond to TrkA-mAb in a manner that parallels the response seen in our rodent study.

Management of sexual dysfunction due to central nervous system disorders: a systematic review.

OBJECTIVE: To systematically review the management of sexual dysfunction due to central nervous system (CNS) disorders. PATIENTS AND METHODS: The review was done according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies were identified independently by two reviewers using electronic searches of MEDLINE and OVID (from January 2004 to August 2014) and hand searches of reference lists and review articles. RESULTS: In patients with CNS disorders, neuro-urological assessment is recommended for both genders before starting any treatment for sexual dysfunction. For men, blood sexual hormones evaluation is the main investigation performed before phosphodiesterase type 5 inhibitors (PDE5Is) treatment, whereas there is no consensus on routine laboratory tests for women. PDE5Is are the first-line medical treatment for men, with the most robust data derived from patients with spinal cord injury assessed by validated questionnaires, mainly the International Index of Erectile Function-15. There is no effective medical treatment for sexual dysfunction in women. Sacral neuromodulation for lower urinary tract dysfunction may improve sexual dysfunction in both genders. CONCLUSIONS: Although sexual dysfunction is a major burden for patients with CNS disorders, high-evidence level studies are rare and only available for PDE5Is treating erectile dysfunction. Well-designed prospective studies are urgently needed for both genders.

Mesenchymal stem cell therapy in treatment of erectile dysfunction: autologous or allogeneic cell sources?

OBJECTIVE: To compare the efficacy of intracavernosal injection of autologous and allogeneic mesenchymal stem cells as potential treatment of erectile dysfunction in an experimental rat model. METHODS: Mesenchymal stem cells were isolated from rat paratesticular fat tissue. Bilateral cavernous nerve injury was carried out followed by immediate intracavernosal injection of either autologous or allogeneic mesenchymal stem cells or mesenchymal stem cell lysates. One month after injection, erectile function was evaluated by means of intracavernosal pressure measurement. All rats were eventually killed, and penile tissues were taken for immunhistochemical and molecular investigation. RESULTS: A total of 36 Sprague-Dawley rats were used. The mean maximum intracavernosal pressure in the sham-operated, autologous and allogeneic mesenchymal stem cell injection groups were significantly better compared with the vehicle injection group (80.5 [3.56], 71.1 [2.9] and 69.2 [3.2] vs 40.33 [4.4], respectively). Mean maximum intracavernosal pressure to mean arterial pressure ratios in the autologous and allogeneic mesenchymal stem cell and mesenchymal stem cell lysate injection groups were not significantly different. CONCLUSIONS: Intracavernosal injection of both autologous or allogeneic mesenchymal stem cells improve erectile functions in a rat model of cavernous nerve injury. Allogeneic mesenchymal stem cells might provide clinicians with ready to use, standardized and, in certain cases, more effective products. More studies focusing on long-term immunological aspects of allogeneic mesenchymal stem cells are required.

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

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