Neurotrophic Effect of Adipose Tissue-Derived Stem Cells on Erectile Function Recovery by Pigment Epithelium-Derived Factor Secretion in a Rat Model of Cavernous Nerve Injury

Therapeutic potential of mesenchymal stem cell-derived exosomal miR-296-5p and miR-337-3p in age-related erectile dysfunction via regulating PTEN/PI3K/AKT pathway

Mesenchymal stem cells (MSCs) are viewed as an increasingly promising treatment for age-related erectile dysfunction (AED). Owing to the limitations of injecting living cells, the injection of exosomes appears to be a more plausible option. However, whether MSC-derived exosomes (MSC-Exos) improve AED and their potential mechanism remains unknown. MSC-Exos were prepared and injected intracavernously into aged rats to determine their effects on AED. Masson's trichrome staining was used to ascertain the changes in the histological structure of the corpus cavernosum. Then miRNA sequencing of MSC-Exos and analysis of the critical exosomal miRNAs were performed, as well as their target pathway enrichment analysis. Real-time quantitative PCR (RT-qPCR) and Western blot assay were performed to reveal the functions of MSC-Exos in regulating the PTEN/PI3K/AKT signaling pathway. Moreover, the effects of MSC-Exos on the corpus cavernosum smooth muscle cells (CCSMCs) apoptosis are explored in vitro. The experimental data validate that intracavernous injection of MSC-Exos ameliorated erectile function in AED rats. Masson's trichrome staining shows MSC-Exos therapy restores the histological structure of the corpus cavernosum by improving the ratios of smooth muscle to collagen. The exosomal miR-296-5p and miR-337-3p target and inhibit PTEN, modulating the PI3K/AKT signaling pathway. Furthermore, exosomes inhibit the apoptosis of CCSMCs. Our findings suggest that MSC-Exos improve AED by delivering miR-296-5p and miR-337-3p to regulate the PTEN/PI3K/AKT signaling pathway. These results bode well for the therapeutic potential of MSC-Exos for AED treatment.

Is there a role for stem cell therapy in erectile dysfunction secondary to cavernous nerve injury? Network meta-analysis from animal studies and human trials

Introduction:

We carried out systematic review and network meta-analysis to investigate the role of stem cell therapy (SCT) in the management of erectile dysfunction (ED) secondary to cavernous nerve injury in rats and post-radical prostatectomy (RP) in humans.

Patients and Methods:

The protocol was registered with PROSPERO database. We searched studies analyzing the efficacy of SCT for ED due to bilateral cavernous nerve injury (BCNI) in rats using Healthcare Databases Advanced Search (HDAS) Export software (MEDLINE, EMBASE, Scopus) from inception to September 2020. The outcome measurements, for 29 animal studies, were intracavernosal pressure (ICP), ICP/MAP (mean arterial pressure) ratio, and histological/molecular changes. All three available human trials evaluating SCT in post-RP ED were assessed for International Index for Erectile Function (IIEF) Score and Erection Hardness Score (EHS).

Results:

For ICP measurement, animal studies were divided into adipose-derived stem cells (ADSCs) subgroup and bone marrow–derived stem cells (BMSCs) subgroup. Pooled analysis of these studies showed a beneficial effect of SCT in improving erectile function in rats with BCNI using network meta-analysis (95% confidence interval, CI; p < 0.001). There was an increase in ICP/MAP ratio in stem cell groups (including co-intervention) compared with control BCNI group. Histological and molecular evaluation of penile tissue revealed an increase in neuronal nitric oxide synthase (nNOS), smooth muscle content, and anti-apoptotic activity. Human trials revealed improved IIEF (70–150% from baseline at 6 months) and EHS (80–200% from baseline).

Conclusion:

Our results confirm that SCT does improve the erectile function in rats having cavernous nerve injury. Similarly, early human results have shown promising results.

PROSPERO registration ID:

CRD42020201343.

Comparative study of different transplantation methods of adipose tissue-derived stem cells in the treatment of erectile dysfunction caused by cavernous nerve injury

We aimed to compare intracavernosal injection (ICI), tail vein injection (IV), and periprostatic injection (PPI) of adipose-derived stem cells (ADSCs) for their ability to improve erectile function in cavernous nerve injury-induced erectile dysfunction (CNIED) rats and to explore the possible mechanism. Eighty-four male SD rats were divided into the sham group (n = 6), BCNI group (bilateral CN crush injury, n = 6), PBS-ICI group (n = 6), PBS-IV group (n = 6), PBS-PPI group (n = 6), ADSC-ICI group (n = 18), ADSC-IV group (n = 18) and ADSC-PPI group (n = 18). ADSCs were labelled with 5-ethynyl-2'-deoxyuridine (EdU), and six rats each in the ADSC-ICI group, ADSC-IV group, and ADSC-PPI group were sacrificed 2, 7, and 28 days after injection. EdU-labelled ADSCs were tracked by immunofluorescence staining. The intracavernosal pressure (ICP)/mean arterial pressure (MAP) ratio, neuronal nitric oxide synthase (nNOS)-positive nerve fibres in the dorsal penile nerve and the smooth muscle/collagen ratio in the cavernosum between groups were also evaluated. ADSCs can significantly improve erectile function through ICI or IV. The two are similar in efficacy and superior to PPI. The mechanism may be that after CN injury, ADSCs are recruited to around the MPG and secrete a variety of neurotrophic factors that promote the repair of the CN, thereby improving erectile function.

Engineered Stem Cells Improve Neurogenic Bladder by Overexpressing SDF-1 in a Pelvic Nerve Injury Rat Model

There is still a lack of sufficient research on the mechanism behind neurogenic bladder (NB) treatment. The aim of this study was to explore the effect of overexpressed stromal cell-derived factor-1 (SDF-1) secreted by engineered immortalized mesenchymal stem cells (imMSCs) on the NB. In this study, primary bone marrow mesenchymal stem cells (BM-MSCs) were transfected into immortalized upregulated SDF-1-engineered BM-MSCs (imMSCs/eSDF-1⁺) or immortalized normal SDF-1-engineered BM-MSCs (imMSCs/eSDF-1⁻). NB rats induced by bilateral pelvic nerve (PN) transection were treated with imMSCs/eSDF-1⁺, imMSCs/eSDF-1⁻, or sham. After a 4-week treatment, the bladder function was assessed by cystometry and voiding pattern analysis. The PN and bladder tissues were evaluated via immunostaining and western blotting analysis. We found that imMSCs/eSDF-1⁺ expressed higher levels of SDF-1 in vitro and in vivo. The treatment of imMSCs/eSDF-1⁺ improved NB and evidently stimulated the recovery of bladder wall in NB rats. The recovery of injured nerve was more effective in the NB+imMSCs/eSDF-1⁺ group than in other groups. High SDF-1 expression improved the levels of vascular endothelial growth factor and basic fibroblast growth factor. Apoptosis was decreased after imMSCs injection, and was detected rarely in the NB+imMSCs/eSDF-1⁺ group. Injection of imMSCs boosted the expression of neuronal nitric oxide synthase, p-AKT, and p-ERK in the NB+imMSCs/eSDF-1⁺ group than in other groups. Our findings demonstrated that overexpression of SDF-1 induced additional MSC homing to the injured tissue, which improved the NB by accelerating the restoration of injured nerve in a rat model.

Intratunical injection of human urine-derived stem cells derived exosomes prevents fibrosis and improves erectile function in a rat model of Peyronie's disease

We aimed to evaluate the effects of intratunical injection of exosomes derived from human urine-derived stem cells (USC-exo) on plaque formation and erectile function in a transforming growth factor-β1 (TGF-β1) induced Peyronie's disease (PD) rat model. Twenty-four SD rats were randomly assigned equally to three groups: (I) Sham group (50 μl phosphate-buffered saline [PBS] injected into the tunica albuginea [TA]), (II) PD group (0.5 μg TGF-β1 in 50 μl PBS injected into the TA) and (III) USC-exo group (0.5 ug TGF-β1 plus 100 μg USC-exo injected into the TA at the same day). The maximum intracavernous pressure (ICP_max ) and mean arterial pressure (MAP) of each group were evaluated 4 weeks after injection. The plaque formation, fibrosis, matrix metalloproteinases (MMPs) and tissue inhibitor of MMPs (TIMPs) in the TA were evaluated. Four weeks after injection, USC-exo group showed more significantly enhanced ICP_max and ICP_max /MAP than PD group (p < .05). USC-exo could significantly ameliorate the TA fibrosis that could be associated with the inhibition of transdifferentiation of fibroblasts into myofibroblasts, decreased expression of TIMPs (TIMP-1, 2, 3) and increased activity of MMPs (MMP-1, 3, 9) in the TA. According to these findings, USC-exo can be a new candidate for the prevention of PD.

Combined Transplantation of Adipose Tissue-Derived Stem Cells and Endothelial Progenitor Cells Improve Diabetic Erectile Dysfunction in a Rat Model

Erectile dysfunction (ED) is a common complication in men suffered with diabetic mellitus. Stem cell transplantation is a promising strategy for the treatment of diabetic ED (DED). In this study, we evaluated whether combined transplantation of adipose tissue-derived stem cells (ADSCs) and endothelial progenitor cells (EPCs) could improve the erectile function of the DED rat model. DED rats were induced via intraperitoneal injection of streptozotocin (50 mg/kg), and ED was screened by apomorphine (100 mg/kg). DED rats were divided into 4 groups (n = 14 each): DED, ADSC, EPC, and ADSC/EPC group. Another 14 age-matched male SD rats with normal erectile function were served as the normal group. The normal group and the DED group were received intracavernous injection with phosphate-buffered saline (PBS). And the other groups were received intracavernous injection with ADSCs (1 × 10⁶), EPCs (1 × 10⁶), and ADSCs/EPCs (0.5 × 10⁶/0.5 × 10⁶), respectively. The total intracavernous pressure (ICP) and mean arterial pressure (MAP) were recorded at day 28 after injection. The endothelium, smooth muscle, and penile dorsal nerves were assessed within cavernoursal tissue. On day 28 after injection, the ADSC/EPC group displayed more significantly enhanced ICP and ICP/MAP than the DED or ADSC or EPC group (p < 0.05). Immunofluorescent analysis and western blot demonstrated that the improvement of erectile function in the ADSC/EPC5 group was associated with increased expression of endothelial marker (CD31) and the correction of eNOS-cGMP-NO signaling. More 5-ethynyl-2′-deoxyuridine- (EdU-) positive EPCs could be found lining in the cavernous endothelial layer in the ADSC/EPC group than the EPC group, which was attributed to the paracrine of vascular endothelial growth factor (VEGF) and stromal-derived factor-1 (SDF-1) by ADSCs. Combined transplantation of ADSCs and EPCs has a synergic effect in repairing the endothelial function of DED rats, and the underlying mechanism might be the paracrine of VEGF and SDF-1 by ADSCs, which improves the recruitment and proliferation of EPCs in the cavernosum.

Understanding Erectile Dysfunction in Hypertensive Patients: The Need for Good Patient Management

Erectile dysfunction (ED) is defined as a man’s consistent or recurrent inability to attain and/or maintain penile erection enough for successful vaginal intercourse. ED affects a large part of the population, increasing its incidence with age and comorbidities. It is estimated by the year 2025, 322 million men will suffer from ED. Incidence of ED has been related not only to chronic diseases such as diabetes mellitus, metabolic syndrome, hyperlipidemia, psychiatric diseases or urinary tract diseases, but also to hypertension and especially to antihypertensive treatments. This review summarizes current knowledge about the management of ED in hypertensive men and its role as cardiovascular disease predictor.

Development of nanotechnology in andrology

Since first introduced in 1980s, nanotechnology has always been the eye-catching point as its providing us with new approaches to explore the microscopic world. Many nanotechnology-associated novel technologies have been brought into clinical use in the past decades and uncountable patients benefited from them, which convinces us of a bright prospect of nanotechnology in the field of medicine. In this review, literatures concerning nanotechnology applications in andrology were retrieved and we made a comprehensive discussion on drug delivery, gene therapy and stem cell therapy use in andrology, which calls for the engagement of nanotechnology.

Adipose Tissue-Derived Stem Cell Therapy for Cavernous Nerve Injury-Induced Erectile Dysfunction in the Rat Model: A Systematic Review and Meta-Analysis Using Methodological Quality Assessment

Background and Objectives

Few studies were evaluated the effect of blindness on outcome in animal models, though a potential effect of blinding has been reported in clinical trials. We evaluated the effects of adipose tissue-derived stem cells (ADSCs) on cavernous nerve injury (CNI)-induced erectile dysfunction (ED) in the rat and examined how proper blinding of the outcome assessor affected treatment effect.

Methods and Results

We searched in Pubmed, EMBASE, Cochrane and Web of Science databases from inception to January 2019. We included CNI animal model, randomized controlled experiments, and ADSC intervention. Erectile function and structural changes were assessed by intracavernous pressure and mean arterial pressure (ICP/MAP) ratios, neuronal nitric oxide synthase (nNOS) levels, cavernous smooth muscle and collagen (CSM/collagen) ratios, and cyclic guanosine monophosphate (cGMP).

Results

Nineteen studies were included in the final meta-analysis. The ICP/MAP ratio of the ADSC treatment group increased compared to the control group (SMD=1.33, 95%CI: 1.11~1.56, I²=72%). The nNOS level (SMD=2.29, 95%CI: 1.74~2.84, I²=75%), CSM/collagen (SMD=2.57, 95%CI: 1.62~3.52; I²=85%), and cGMP (SMD=2.96, 95%CI: 1.82~4.10, I²=62%) were also increased in the ADSC treatment group. Preplanned subgroup analysis was conducted to explore the source of heterogeneity. Five studies with blinded outcome assessment were significantly less effective than the unblinded studies (SMD=1.33, 95%CI: 0.86~1.80; SMD=1.81, 95%CI: 1.17~2.46, respectively).

Conclusions

ADSCs might be effective in improving erectile function and structural change in CNI-induced ED. However, non-blinded outcome assessors might cause detection bias and overestimate treatment efficacy. Therefore, the ADSC efficacy must be further evaluated with a rigorous study design to avoid bias.

Emerging Treatments for Erectile Dysfunction: a Review of Novel, Non-surgical Options

PURPOSE OF REVIEW

To review novel, non-surgical therapies for erectile dysfunction (ED).

RECENT FINDINGS

Recently, a landmark study identified the SIM1 locus, involved in the leptin-melanocortin pathway, as an independent risk factor for ED and a potential target for novel therapies. The recent literature otherwise has focused on low-intensity shock wave therapy (LiSWT), with several randomized trials and meta-analyses suggesting therapeutic efficacy. There are few novel oral agents for ED. There is growing evidence suggesting efficacy of intracavernosal stem cells therapy and low-intensity shock wave therapy (LiSWT), although these therapies are still investigational. A better understanding of the pathophysiologic spectrum of ED will offer new opportunities for novel, non-surgical therapies for ED.

Extracellular Vesicles From Human Urine-Derived Stem Cells Ameliorate Erectile Dysfunction in a Diabetic Rat Model by Delivering Proangiogenic MicroRNA

INTRODUCTION

Stem cell therapies represent a promising new frontier for the treatment of refractory diabetic erectile dysfunction (DED). The use of stem cell-derived extracellular vesicles (EVs) is a novel strategy for cell-free stem cell therapy. We have reported that urine-derived stem cells (USCs) can improve DED; however, the therapeutic effects of EVs secreted by USCs (USC-EVs) remain unknown.

AIM

To determine the therapeutic effects of USC-EVs on DED in a rat model.

METHODS

USC-EVs were isolated from conditioned medium by ultracentrifugation. DED was induced in male Sprague-Dawley rats via an intraperitoneal injection of streptozotocin. Sixteen DED rats were divided into phosphate-buffered saline (PBS) and USC-EV groups. Eight normal rats served as the normal control group. PBS or USC-EVs were transplanted into the corpora cavernosa in the corresponding groups.

MAIN OUTCOME MEASURE

Intracavernosal pressure (ICP), mean arterial pressure (MAP), expression of endothelial markers (CD31), endothelial nitric oxide synthase (eNOS), phospho-eNOS, and neural nitric oxide synthase (nNOS) were assessed in each group. Masson's trichrome staining was used to determine the collagen deposition and ratio of smooth muscle cells to collagen. The microRNA (miRNA) cargo of USC-EVs was characterized by high-throughput RNA sequencing.

RESULTS

Recovery of erectile function was observed in the USC-EV group, as represented by improved ICP and ICP/MAP ratio. CD31, eNOS, phospho-eNOS, and nNOS expression in the penis was significantly improved in the USC-EV group. In addition, the ratio of smooth muscle to collagen was significantly increased in the USC-EV group. RNA sequencing revealed that USC-EVs were enriched for distinct classes of miRNA (miR-21-5p, let-7 family, miR-10 family, miR-30 family, and miR-148a-3p) that promote angiogenesis.

CONCLUSION

USC-EV transplantation can ameliorate DED in rats. Its mechanism may involve the delivery of proangiogenic miRNA. Ouyang B, Xie Y, Zhang C, et al. Extracellular Vesicles From Human Urine-Derived Stem Cells Ameliorate Erectile Dysfunction in a Diabetic Rat Model by Delivering Proangiogenic MicroRNA. Sex Med 2019;7:241-250.

PEDF Reduces the Severity of Herpetic Simplex Keratitis in Mice

Purpose

The purpose of this study was to explore the effects of pigment epithelium derived factor (PEDF) and PEDF-derived peptides Mer44 and Mer34 on the severity of herpetic simplex keratitis (HSK) in mice.

Methods

Adult C57BL/6 mice were infected ocularly with the herpes simplex virus type 1 (HSV-1, McKrae strain) and injected subconjunctivally with PEDF, Mer44, or Mer34. Corneal nerve degeneration, neovascularization, sensitivity, neutrophils, macrophages and CD4+ T-cell infiltration, virus contents, and expressions of VEGF, PEDF, and proinflammatory factors were evaluated during acute period. The direct inhibitory effect of PEDF on HSV-1 replication was further evaluated in cultured monkey Vero cells.

Results

Following HSV-1 infection, corneal PEDF expression decreased at 3 and 7 days postinfection (dpi) but increased at 15 dpi, and returned to the similar level of normal mice at 45 dpi, which was accompanied with the progress of corneal nerve degeneration and neovascularization. Exogenous PEDF application attenuated corneal nerve degeneration and neovascularization and improved the impaired corneal sensitivity. Moreover, PEDF attenuated the neutrophils, but not macrophage or CD4+ T-cell infiltration, with the reduced expressions of IL-1β, IL-6, TNF-α, and VEGF. In addition, PEDF inhibited the replication of HSV-1 both in vitro and in mice. Mer44 attenuated corneal nerve degeneration more significantly than Mer34, whereas Mer34 inhibited corneal neovascularization.

Conclusions

PEDF and its derived peptides reduce the severity of herpetic simplex keratitis in mice, representing the potential therapeutic approach to control HSK lesions.

Advances in stem cell therapy for erectile dysfunction

INTRODUCTION

Stem cell (SC) application is a promising area of research in regenerative medicine, with the potential to treat, prevent, and cure disease. In recent years, the number of studies focusing on SCs for the treatment of erectile dysfunction (ED) and other sexual dysfunctions has increased significantly.

AREAS COVERED

This review includes critical ED targets and preclinical studies, including the use of SCs and animal models in diabetes, aging, cavernous nerve injury, and Peyronie's disease. A literature search was performed on PubMed for English articles.

EXPERT OPINION

Combination treatment offers better results than monotherapy to improve pathological changes in diabetic ED. Regenerative medicine is a promising approach for the maintenance of sexual health and erectile function later in life. Cavernous nerve regeneration and vascular recovery employing SC treatment may be focused on radical prostatectomy-induced ED. Notwithstanding, there are a number of hurdles to overcome before SC-based therapies for ED are considered in clinical settings. Paracrine action, not cellular differentiation, appears to be the principal mechanism of action underlying SC treatment of ED. Intracavernosal injection of a single SC type should be the choice protocol for future clinical trials.

Icariside II Promotes the Differentiation of Adipose Tissue-Derived Stem Cells to Schwann Cells to Preserve Erectile Function after Cavernous Nerve Injury

Icariside II (ICA II) is used in erectile dysfunction treatment. Adipose tissue-derived stem cells (ADSCs) are efficient at improving erectile function. This study aimed to explore the action mechanism of ADSCs in improving erectile function. ADSCs were isolated from the adipose tissues of rats. Cell proliferation was determined using the Cell Counting Kit-8 (CCK-8) assay. The expressions of mRNA and protein were determined separately through qRT-PCR and western blot. The endogenous expressions of related genes were regulated using recombinant plasmids and cell transfection. A Dual-Luciferase Reporter Assay was performed to determine the interaction between miR-34a and STAT3. Rat models with bilateral cavernous nerve injuries (BCNIs) were used to assess erectile function through the detection of mean arterial pressure (MAP) and intracavernosal pressure (ICP). ICA II promoted ADSCs' proliferation and differentiation to Schwann cells (SCs) through the inhibition of miR-34a. Suppressed miR-34a promoted the differentiation of ADSCs to SCs by upregulating STAT3. ICA II promoted the differentiation of ADSCs to SCs through the miR-34a/STAT3 pathway. The combination of ICA II and ADSCs preserved the erectile function of the BCNI model rats. ADSCs treated with ICA II markedly preserved the erectile function of the BCNI model rats, which was reversed through miR-34a overexpression. ICA II promotes the differentiation of ADSCs to SCs through the miR-34a/STAT3 pathway, contributing to erectile function preservation after the occurrence of a cavernous nerve injury.

S-nitrosylation of NOS pathway mediators in the penis contributes to cavernous nerve injury-induced erectile dysfunction

cGMP-independent nitric oxide (NO) signaling occurs via S-nitrosylation. We evaluated whether aberrant S-nitrosylation operates in the penis under conditions of cavernous nerve injury and targets proteins involved in regulating erectile function. Adult male Sprague-Dawley rats underwent bilateral cavernous nerve crush injury (BCNI) or sham surgery. Rats were given a denitrosylation agent N-acetylcysteine (NAC, 300 mg/kg/day) or vehicle in drinking water starting 2 days before BCNI and continuing for 2 weeks following surgery. After assessment of erectile function (intracavernous pressure), penes were collected for measurements of S-nitrosylation by Saville-Griess and TMT-switch assays and PKG-I function by immunoblotting of phospho (P)-VASP-Ser-239. Erectile function was decreased (P<0.05) after BCNI, and it was preserved (P<0.05) by NAC treatment. Total S-nitrosothiols and total S-nitrosylated proteins were increased (P<0.05) after BCNI, and these were partially prevented by NAC treatment. S-nitrosylation of sGC was increased (P<0.05) after BCNI, and it was prevented (P<0.05) by NAC treatment. S-nitrosylation of eNOS was increased (P<0.05) after BCNI, and showed a trend towards decrease by NAC treatment. Protein expression of P-VASP-Ser-239 was decreased (P<0.05) after BCNI, and showed a trend towards increase by NAC treatment. In conclusion, erectile dysfunction following BCNI is mediated in part by S-nitrosylation of eNOS and its downstream signaling mediator GC, while denitrosylation protects erectile function by preserving the NO/cGMP signaling pathway.

Transplantation of Human Urine-Derived Stem Cells Transfected with Pigment Epithelium-Derived Factor to Protect Erectile Function in a Rat Model of Cavernous Nerve Injury

The aim of this study was to investigate whether intracavernous injection of urine-derived stem cells (USCs) or USCs genetically modified with pigment epithelium-derived factor (PEDF) could protect the erectile function and cavernous structure in a bilateral cavernous nerve injury-induced erectile dysfunction (CNIED) rat model. USCs were cultured from the urine of six healthy male donors. Seventy-five rats were randomly divided into five groups ( n = 15 per group): sham, bilateral cavernous nerve (CN) crush injury (BCNI), USC, USC^GFP+, and USC^GFP/PEDF+ groups. The sham group received only laparotomy without CN crush injury and intracavernous injection with phosphate-buffered saline (PBS). All of the other groups were subjected to BCNI and intracavernous injection with PBS, USCs, USCs^GFP+, or USCs^GFP/PEDF+, respectively. The total intracavernous pressure (ICP) and the ratio of ICP to mean arterial pressure (ICP/MAP) were recorded. The penile dorsal nerves, the endothelium, and the smooth muscle were assessed within the penile tissue. The USC and USC^GFP/PEDF+ groups displayed more significantly enhanced ICP and ICP/MAP ratio ( p < 0.05) 28 days after cell transplantation. Immunohistochemistry (IHC) and Western blot analysis demonstrated that the protection of erectile function and the cavernous structure by USCs^GFP/PEDF+ was associated with an increased number of nNOS-positive fibers within the penile dorsal nerves, improved expression of endothelial markers (CD31 and eNOS) and a smooth muscle marker (smoothelin), an enhanced smooth muscle to collagen ratio, decreased expression of transforming growth factor-β1 (TGF-β1), and decreased cell apoptosis in the cavernous tissue. The paracrine effect of USCs and USCs^GFP/PEDF+ prevented the destruction of erectile function and the cavernous structure in the CNIED rat model by nerve protection, thereby improving endothelial cell function, increasing the smooth muscle content, and decreasing fibrosis and cell apoptosis in the cavernous tissue.

Erythropoietin Modification Enhances the Protection of Mesenchymal Stem Cells on Diabetic Rat-Derived Schwann Cells: Implications for Diabetic Neuropathy

Diabetes-triggered apoptosis of Schwann cells (SC) contributes to the degradation of diabetic peripheral neuropathy (DNP). In recent years, mesenchymal stem cells (MSC) were applied to DPN repair and it was demonstrated that paracrine secretion played a key role in neuroprotection exerted by MSC. Erythropoietin (EPO) is a potent cytokine capable of reducing apoptosis of SC. However, the expression of EPO in MSC is limited. In this study, we hypothesized that overexpression of EPO in MSC (EPO-MSC) may significantly improve their neuroprotective potentials. The EPO overexpression in MSC was achieved by lentivirus transduction. SC derived from the periphery nerve of diabetic rats were cocultured with MSC or EPO-MSC in normal or high glucose culture condition, respectively. In normal glucose culture condition, the overexpression of EPO in MSC promoted the MSC-induced restoration of SC from diabetic rats, including increases in GSH level and cell viability, decrease in TUNEL apoptosis, upregulation of antiapoptotic proteins, p-Akt, and Bcl-2, and downregulation of proapoptotic proteins, cleaved caspase-3, and Bax. The subsequent results in high glucose culture condition showed similar promotions achieved by EPO-MSC. Thus, it could be concluded that EPO-MSC possessed a potent potential in hampering apoptosis of SC, and the suppression was probably attributed to attenuating oxidative stress and regulating apoptosis related protein factors.

Erectile dysfunction post-radical prostatectomy - a challenge for both patient and physician

Post-radical prostatectomy erectile dysfunction (post RP ED) is a major postoperative complication with a great impact on the quality of life of the patients. Until present, no proper algorithm or guideline based on the clinical trials has been established for the management of post RP ED. According to literature, it is better to initiate a penile rehabilitation program as soon as possible after surgery than doing nothing, in order to prevent and limit the postoperative local hypoxygenation and fibrosis. The results of numerous clinical trials regarding the effectiveness of the phosphodiesterase 5 inhibitors therapy on post RP ED have made them the gold standard treatment. Encouraging results have been achieved in studies with vacuum erectile devices, intraurethral suppositories with alprostadil and intracavernosal injections, but due to their side effects, especially in the cases of intracavernosal injections and intraurethral suppositories, their clinical use was limited therefore making them a second line option for the post RP ED treatment. What should not be forgotten is that penile implant prosthesis has proven very effective, numerous studies confirming high rates of satisfaction for both patients and partners.

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

INTRODUCTION

Stem cells for sexual disorders are steadily being introduced into clinical trials. Two conditions of importance are the main target for this line of treatment, especially when regarding the wide array of translational and basic science highlighting the potential advantages of regenerative therapy: erectile dysfunction (ED) and more recently Peyronie disease (PD). Cellular therapy offers a treatment modality that might reverse disease progression. It would be used in a curative setting, in contrast to other pharmaceutical agents that are currently available.

AIM

To review basic preclinical studies and recent clinical trials of stem cells on ED and PD.

METHODS

A search of the medical literature for the following terms was performed using PubMed: stem cells, cellular therapy, erectile dysfunction, Peyronie's disease, and clinical trial.

MAIN OUTCOME MEASURES

A non-systematic narrative review and critical reflection on preclinical and clinical studies administering stem cells for ED and PD in animal models and human subjects.

RESULTS

Numerous studies have confirmed the beneficial functional effects of stem cell injection in established animal models on ED and PD. Various stem cell types have been adopted, from embryonic to adult mesenchymal cell types. Each cell type offers distinctive advantages and disadvantages. Diverse administrations of stem cells were investigated, with insignificant variability in the ultimate results. Stem cells appear to have a pronounced paracrine effect, rather than the classic engraftment and differentiation hypothesis. Phase 1 clinical trials using stem cells have not reported any severe adverse events in animals. However, these results cannot be extrapolated to draw any conclusions about efficacy in human patients.

CONCLUSION

Stem cells have an established efficacy in preclinical studies and early clinical trials. Studies are currently being published demonstrating the safety of intrapenile injection of autologous bone marrow- and adipose tissue-derived stem cells. Soebadi MA, Milenkovic U, Weyne E, et al. Stem Cells in Male Sexual Dysfunction: Are We Getting Somewhere? Sex Med Rev 2017;5:222-235.

Innovative trends and perspectives for erectile dysfunction treatment: A systematic review

Objective

To review contemporary knowledge concerning the innovative trends and perspectives in the treatment of erectile dysfunction (ED).

Methods

Medline was reviewed for English-language journal articles between January 2000 and March 2016, using the terms ‘erectile dysfunction treatments’, ‘new trends’ and ‘perspectives’. In all, 114 original articles and 16 review articles were found to be relevant. Of the 76 cited papers that met the inclusion criteria, 51 papers had level of evidence of 1a–2b, whilst 25 had level of evidence of 3–4. Criteria included all pertinent review articles, randomised controlled trials with tight methodological design, cohort studies, and retrospective analyses. We also manually reviewed references from selected articles.

Results

Several interesting studies have addressed novel phosphodiesterase type 5 inhibitors (PDE5Is), orodispersible tablets, their recent chronic use, and combination with other agents. A few controlled studies have addressed herbal medicine as a sole or additional treatment for ED. Experimental studies and exciting review papers have addressed stem cells as novel players in the field of ED treatment. Other recent articles have revised the current status of low-intensity extracorporeal shockwave therapy in the field of ED. A few articles without long-term data have addressed new technologies that included: external penile support devices, penile vibrators, tissue engineering, nanotechnology, and endovascular tools for ED treatment.

Conclusions

The current treatment of ED is still far from ideal. We expect to see new drugs and technologies that may revolutionise ED treatment, especially in complex cases.