Mesenchymal stem cell-derived exosomes ameliorate erection by reducing oxidative stress damage of corpus cavernosum in a rat model of artery injury

Revisiting experimental models of erectile dysfunction and their value in drug discovery and development

INTRODUCTION

Erectile dysfunction (ED) is a common condition that often signals underlying endothelial dysfunction, although the underlying causative factor(s) are likely complex and multifactorial. Various animal models have been developed to provide a research platform to study ED and served as an important basis for the discovery and subsequent development of novel therapeutic drugs for ED.

AREAS COVERED

The review article provides an overview of various animal models in ED research with an emphasis on important drug target discovery relating to each specific experimental model. The authors highlight translation from basic science research to major preclinical and clinical studies in this evolving field of ED research.

EXPERT OPINION

Animal models simulate the pathological features of various types of ED and clarify their molecular mechanisms. These mechanisms aid in discovering drug targets, while established ED models also provide a basis for validating drug efficacy, safety, and specific action mechanisms. The development of techniques in detection methods, cellular experimental, and omics has a profound impact on disease prediction, model evaluation, and optimization of therapeutic modalities. On this basis, many drug therapies targeting these ED-related mechanisms, especially in the nitric oxide/cyclic guanosine monophosphate pathways have been applied in preclinical studies. However, focusing on drug development for those types of ED where phosphodiesterase 5 inhibitor therapy is limited may be more valuable.

The promise of mesenchymal stromal/stem cells in erectile dysfunction treatment: a review of current insights and future directions

Erectile dysfunction is a common and multifactorial condition that significantly impacts men's quality of life. Traditional treatments, such as phosphodiesterase type 5 inhibitors (PDE5i), often fail to provide lasting benefits, particularly in patients with underlying health conditions. In recent years, regenerative medicine, particularly stem cell therapies, has emerged as a promising alternative for managing erectile dysfunction. This review explores the potential of mesenchymal stromal/stem cells (MSCs) and their paracrine effects, including extracellular vesicles (EVs), in the treatment of erectile dysfunction. MSCs have shown remarkable potential in promoting tissue repair, reducing inflammation, and regenerating smooth muscle cells, offering therapeutic benefits in models of erectile dysfunction. Clinical trials have demonstrated positive outcomes in improving erectile function and other clinical parameters. This review highlights the promise of MSC therapy for erectile dysfunction, discusses existing challenges, and emphasizes the need for continued research to refine these therapies and improve long-term patient outcomes.

Regenerative therapies for erectile dysfunction: a systematic review, Bayesian network meta-analysis, and meta-regression

BACKGROUND

Current guidelines advocate a shared decision-making process approach to erectile dysfunction management, and while there is growing interest in regenerative therapies such as stem cell therapy, platelet-rich plasma injections, and low-intensity shockwave therapy for erectile dysfunction, comparative data on the efficacy of these modalities are limited.

AIM

This systematic review and network meta-analysis aims to compare stem cell therapy, platelet-rich plasma injections, and low-intensity shockwave therapy for managing erectile dysfunction and quantify their impact on the International Index of Erectile Function (IIEF).

METHODS

In January 2024, a systematic search of online databases was performed to identify randomized clinical trials related to stem cell therapy, platelet-rich plasma injections, and low-intensity shockwave therapy in erectile dysfunction. Eligible articles reported outcomes using the IIEF score. Data were inputted into Review Manager 5.4 for pairwise meta-analysis. Data were then used to build a network in R Studio. These networks were used to model 200 000 Markov Chains via MonteCarlo sampling. The results are expressed as standardized mean difference (SMD) with 95% credible intervals (CrI). Meta-regression was used to adjust for PDE5is use.

OUTCOMES

Impact on the International Index of Erectile Function.

RESULTS

A total of 16 studies involving 907 patients were analyzed. The standardized mean difference (SMD) vs control for stem cell therapy was 0.92 [95% CrI -0.49, 2.3]. For platelet-rich plasma, the SMD vs control was 0.83 [95% CrI 0.15, 1.5], and for low-intensity shockwave therapy, the SMD vs control was 0.84 [95% CrI 0.49, 1.2]. When stratifying low-intensity shockwave therapy by dose, the SMD vs control at 0.15 mJ/mm2 was 1.1 [95% CrI 0.36, 1.9], while at 0.09 mJ/mm2, it was 0.75 [95% CrI 0.26, 1.2]. Meta-regression adjusting for the administration of PDE5 inhibitors yielded non-significant results.

CLINICAL IMPLICATIONS

The findings suggest that stem cells, platelet-rich plasma, and low intensity shockwave therapy, particularly at 0.15 and 0.09 mJ/mm2, may offer improvements in erectile function.

STRENGTHS AND LIMITATIONS

The strength is the robust statistical methods. Limitations are in heterogeneity in control groups and follow-up durations among included studies.

CONCLUSION

Shockwave therapy and platelet-rich plasma demonstrated statistically significant improvements, though the clinical relevance and extent of their impact remain questionable. Further research is necessary to determine the efficacy of stem cell therapies for erectile function.

An update on the use of stem cell therapy for erectile dysfunction

Objective

This systematic review aimed to analyze animal and human trial data to better understand the efficacy of stem cell therapy (SCT) for erectile dysfunction (ED) and the obstacles that may hinder its application in this field.

Methods

We searched electronic databases, including PubMed and Scopus, for published studies with the Medical Subject Heading terms of "erectile dysfunction" (AND) "stem cell therapy" (OR) "erectile dysfunction" (AND) "clinical trial of stem cell therapy" (OR) "stem cell therapy" (AND) "sexual dysfunction". The search was limited to English-language journals and full papers only. The initial search resulted in 450 articles, of which 90 relevant to our aims were included in the analysis.

Results

ED is a multifactorial disease. Current treatment options rely on pharmacotherapy as well as surgical options. Patients may have side effects or unsatisfactory results following the use of these treatment options. SCT may restore pathophysiological changes leading to ED rather than treating the symptoms. It has been evaluated in animal models and shown promising results in humans. Results confirm that SCT does improve erectile function in animals with different types of SC use. In humans, evidence showed promising results, but the trials were heterogeneous and limited mainly by a lack of randomization and the small sample size. Many challenges could limit future research in this field, including ethical dilemmas, regulation, patient recruitment, the cost of therapy, and the lack of a standardized SCT regimen. Repairing and possibly replacing diseased cells, tissue, or organs and eventually retrieving normal function should always be the goals of any therapy, and this can only be guaranteed by SCT.

Conclusion

SCT is a potential and successful treatment for ED, particularly in patients who are resistant to the classic therapy. SCT may promote nerve regeneration and vascular cell regeneration, not only symptomatic treatment.

Repeated Injections of Mesenchymal Stem Cell-Derived Exosomes Ameliorate Erectile Dysfunction in a Cavernous Nerve Injury Rat Model

PURPOSE

To evaluate the therapeutic effect of repeated injections of mesenchymal stem cell (MSC)-derived exosomes on the erectile dysfunction (ED) of bilateral cavernous nerve injury (BCNI) rat model and to identify potential target genes of these injections.

MATERIALS AND METHODS

MSC-derived exosomes were isolated using an aqueous two-phase system. Rats were randomly assigned into four groups: Normal, BCNI, exosome once, and exosome-repeat groups. After four weeks, we measured the intracavernosal pressure (ICP)/mean arterial pressure (MAP) ratio to evaluate erectile function and examined cavernous nerve tissues for histological and molecular analyses. RNA sequencing in penile tissues was used to determine differentially expressed genes and was verified by quantitative polymerase chain reaction. Human umbilical vein endothelial cells (HUVECs) were used for in vitro studies to analyze biological roles.

RESULTS

The ICP/MAP ratios in the exosome-once and exosome-repeat groups were significantly increased compared to those in the BCNI group. Interestingly, the ICP/MAP ratio showed a greater increase in the exosome-repeat group, which also showed significantly increased smooth muscle/collagen ratio, α-smooth muscle actin and neuronal nitric oxide synthase expression, and cyclic guanosine monophosphate level compared to the BCNI and exosome-once groups. Three genes were significantly differentially expressed in the exosome group, among which Ras homolog family member B promoted cell proliferation and angiogenesis of HUVECs.

CONCLUSIONS

Repeated injections of MSC-derived exosomes can be effective in the treatment of rat models with ED induced by cavernous nerve injury.

Research progress on the therapeutic application of extracellular vesicles in erectile dysfunction

Erectile dysfunction (ED) is one of the most common male sexual dysfunctions and is related to many pathogenic factors. However, first-line treatment, represented by phosphodiesterase 5 inhibitors, is unable to maintain long-term efficacy. Extracellular vesicles (EVs) have recently attracted the attention of researchers in the fields of cardiovascular disease, neurologic disease, and regenerative medicine and may become a treatment for ED. This article reviews recent applications of EVs in the treatment of ED from the aspects of the source, the therapeutic mechanism, and the strategies to enhance therapeutic efficacy. These research advances lay the foundation for further research and provide references for in-depth understanding of the therapeutic mechanism and possible clinical application of EVs in ED.

Molecular and spatial signatures of human and rat corpus cavernosum physiopathological processes at single-cell resolution

The composition and cellular heterogeneity of the corpus cavernosum (CC) microenvironment have been characterized, but the spatial heterogeneity at the molecular level remains unexplored. In this study, we integrate single-cell RNA sequencing (scRNA-seq) and spatial transcriptome sequencing to comprehensively chart the spatial cellular landscape of the human and rat CC under normal and disease conditions. We observe differences in the proportions of cell subtypes and marker genes between humans and rats. Based on the analysis of the fibroblast (FB) niche, we also find that the enrichment scores of mechanical force signaling vary across different regions and correlate with the spatial distribution of FB subtypes. In vitro, the soft and hard extracellular matrix (ECM) induces the differentiation of FBs into apolipoprotein (APO)+ FBs and cartilage oligomeric matrix protein (COMP)+ FBs, respectively. In summary, our study provides a cross-species and physiopathological transcriptomic atlas of the CC, contributing to a further understanding of the molecular anatomy and regulation of penile erection.

Mesenchymal stem cell secretome: A promising therapeutic strategy for erectile dysfunction?

Objective

The secretome, comprising bioactive chemicals released by mesenchymal stem cells (MSCs), holds therapeutic promise in regenerative medicine. This review aimed to explore the therapeutic potential of the MSC secretome in regenerative urology, particularly for treating erectile dysfunction (ED), and to provide an overview of preclinical and clinical research on MSCs in ED treatment and subsequently to highlight the rationales, mechanisms, preclinical investigations, and therapeutic potential of the MSC secretome in this context.

Methods

The review incorporated an analysis of preclinical and clinical research involving MSCs in the treatment of ED. Subsequently, it delved into the existing knowledge regarding the MSC secretome, exploring its therapeutic potential. The methods included a comprehensive examination of relevant literature to discern the processes underlying the therapeutic efficacy of the MSC secretome.

Results

Preclinical research indicated the effectiveness of the MSC secretome in treating various models of ED. However, the precise mechanisms of its therapeutic efficacy remain unknown. The review provided insights into the anti-inflammatory, pro-angiogenic, and trophic properties of the MSC secretome. It also discussed potential advantages, such as avoiding issues related to cellular therapy, including immunogenicity, neoplastic transformation, and cost.

Conclusion

This review underscores the significant therapeutic potential of the MSC secretome in regenerative urology, particularly for ED treatment. While preclinical studies demonstrate promising outcomes, further research is essential to elucidate the specific mechanisms underlying the therapeutic efficacy before clinical application. The review concludes by discussing future perspectives and highlighting the challenges associated with the clinical translation of the MSC secretome in regenerative urology.

Treatment of erectile dysfunction by intracavernosal administration of mesenchymal stem cells in patients with diabetes mellitus

Erectile dysfunction is observed in about 50% of men. It has been found that diabetes mellitus increases its prevalence to 19-86.3%, necessitating attention to a therapeutic strategy. Among the available treatment methods, intracavernosal injections of mesenchymal stem cells have proven to be particularly effective.

OBJECTIVE

The purpose of study is to assess and analyse the effectiveness of their use in the treatment of erectile dysfunction in patients with diabetes mellitus.

MATERIALS AND METHODS

The literature search was conducted using systematic methods and analysis in databases such as Web of Science, Scopus, PubMed, Elsevier, and Springer, with 41 sources included for further review.

RESULTS

The study highlights microangiopathic and neuropathic links as key factors in erectile dysfunction development in diabetic patients, stemming from endothelial dysfunction and conductivity disturbances. Mesenchymal stem cell therapy from bone marrow, adipose tissue, and umbilical cord mitigates pathogenic impact through regenerative and anti-apoptotic effects. Due to this, most studies indicate high efficacy of the treatment and rapid therapeutic action through intracavernosal administration. Some studies suggest an increase in the body's receptor sensitivity to other drugs, such as sildenafil.

CONCLUSION

From the perspective of further research on this issue, standardising the preparation of stem cells and the treatment method using a large sample size is essential to introduce such a method as an extremely promising therapy for this delicate issue in men into practical medicine. The practical value of the study lies in the systematisation of information on different sources of mesenchymal stem cells for treating erectile dysfunction.

Strategies and Challenges of Mesenchymal Stem Cells-Derived Extracellular Vesicles in Infertility

Having genetically related offspring remains an unattainable dream for couples with reproductive failure. Mesenchymal stem cells (MSCs) are multipotent stromal cells derived from various human tissues and organs. As critical paracrine effectors of MSCs, extracellular vesicles (EVs) can carry and deliver bioactive content, thereby participating in intercellular communication and determining cell fate. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have shown promising therapeutic effects, including repairing injured endometria, restoration of ovarian functions, and improving sperm quantity, morphology, and motility, owing to their regenerative potential, abundant sources, high proliferation rates, low immunogenicity, and lack of ethical issues. However, limited knowledge on purification and isolation of MSC-EVs, therapeutic effects, and unpredictable safety have caused challenges in overcoming female and male infertility. To overcome them, future studies should focus on modification/engineering of MSC-EVs with therapeutic biomolecules and combining attractive biomaterials and MSC-EVs. This review highlights the latest studies on MSC-EVs therapies in infertility and the major challenges that must be overcome before clinical translation.

Research Advances in Stem Cell Therapy for Erectile Dysfunction

Erectile dysfunction (ED) is a common clinical condition that mainly affects men aged over 40 years. Various causes contribute to the progression of ED, including pelvic nerve injury, diabetes, metabolic syndrome, age, Peyronie's disease, smoking, and psychological disorders. Current treatments for ED are limited to symptom relief and do not address the root cause. Stem cells, with their powerful ability to proliferate and differentiate, are a promising approach for the treatment of male ED and are gradually gaining widespread attention. Current uses for treating ED have been studied primarily in experimental animals, with most studies observing improvements in erectile quality as well as improvements in erectile tissue. However, research on stem cell therapy for human ED is still limited. This article summarizes the recent literature on basic stem cell research on ED, including cavernous nerve injury, aging, diabetes, and sclerosing penile disease, and describes mechanisms of action and therapeutic effects of various stem cell therapies in experimental animals. Stem cells are also believed to interact with host tissue in a paracrine manner, and improved function can be supported through both implantation and paracrine factors. To date, stem cells have shown some preliminary promising results in animal and human models of ED.

Exosomes and Signaling Nanovesicles from the Nanofiltration of Preconditioned Adipose Tissue with Skin-B® in Tissue Regeneration and Antiaging: A Clinical Study and Case Report

Background and Objectives: This three-year clinical trial aimed to demonstrate that only the signaling vesicles produced by ADSCa, containing mRNA, microRNA, growth factors (GFs), and bioactive peptides, provide an advantage over classical therapy with adipose disaggregate to make the tissue regeneration technique safer due to the absence of interfering materials and cells, while being extremely minimally invasive. The infiltration of disaggregated adipose nanofat, defined by the Tonnard method, for the regeneration of the dermis and epidermis during physiological or pathological aging continues to be successfully used for the presence of numerous adult stem cells in suspension (ADSCa). An improvement in this method is the exclusion of fibrous shots and cellular debris from the nanofat to avoid inflammatory phenomena by microfiltration. Materials and Methods: A small amount of adipose tissue was extracted after surface anesthesia and disaggregated according to the Tonnard method. An initial microfiltration at 20/40 microns was performed to remove fibrous shots and cellular debris. The microfiltration was stabilized with a sterile solution containing hyaluronic acid and immediately ultrafiltered to a final size of 0.20 microns to exclude the cellular component and hyaluronic acid chains of different molecular weights. The suspension was then injected into the dermis using a mesotherapy technique with microinjections. Results: This study found that it is possible to extract signaling microvesicles using a simple ultrafiltration system. The Berardesca Scale, Numeric Rating Scale (NRS), and Modified Vancouver Scale (MVS) showed that it is possible to obtain excellent results with this technique. The ultrafiltrate can validly be used in a therapy involving injection into target tissues affected by chronic and photoaging with excellent results. Conclusions: This retrospective clinical evaluation study allowed us to consider the results obtained with this method for the treatment of dermal wrinkles and facial tissue furrows as excellent. The method is safe and an innovative regenerative therapy as a powerful and viable alternative to skin regeneration therapies, antiaging therapies, and chronic inflammatory diseases because it lacks the inflammatory component produced by cellular debris and fibrous sprouts and because it can exclude the mesenchymal cellular component by reducing multiple inflammatory cytokine levels.

Stem cell therapy for erectile dysfunction: a systematic review

INTRODUCTION

Erectile dysfunction (ED) is a common condition that negatively affects men's quality of life. It can have various causes, including psychological, vascular, and neurologic factors. Existing treatments for ED mainly focus on symptom relief rather than addressing the underlying cause. Stem cells (SCs) have shown potential as a therapeutic approach for ED due to their anti-inflammatory properties.

OBJECTIVES

This systematic review aims to assess the current status of trials and determine the potential impact of SCs on male sexual health.

METHODS

A comprehensive search strategy was employed to gather relevant articles from 6 electronic databases. The search included articles published until March 2023. The reference lists of articles were manually reviewed to identify additional studies of relevance. The eligibility criteria for inclusion in the analysis focused on clinical trials involving humans that evaluated the safety and efficacy of SC therapy for ED. Exclusion criteria encompassed case reports, case series, abstracts, reviews, and editorials, as well as studies involving animals or SC derivatives. Data extraction was performed via a standardized form with a focus on erectile outcomes.

RESULTS

A total of 2847 articles were initially identified; 18 were included in the final analysis. These studies involved 373 patients with ED and various underlying medical conditions. Multiple types of SC were utilized in the treatment of ED: mesenchymal SCs, placental matrix-derived mesenchymal SCs, mesenchymal SC-derived exosomes, adipose-derived SCs, bone marrow-derived mononuclear SCs, and umbilical cord blood SCs.

CONCLUSION

SC therapy shows promise as an innovative and safe treatment for organic ED. However, the lack of standardized techniques and controlled groups in many studies hampers the ability to evaluate and compare trials.

Therapeutic efficacy and promise of stem cell-derived extracellular vesicles in Alzheimer's disease and other aging-related disorders

The term extracellular vesicles (EVs) refers to a variety of heterogeneous nanovesicles secreted by almost all cell types, primarily for intercellular communication and maintaining cellular homeostasis. The role of EVs has been widely reported in the genesis and progression of multiple pathological conditions, and these vesicles are suggested to serve as 'liquid biopsies'. In addition to their use as biomarkers, EVs secreted by specific cell types, especially with stem cell properties, have shown promise as cell-free nanotherapeutics. Stem cell-derived EVs (SC-EVs) have been increasingly used as an attractive alternative to stem cell therapies and have been reported to promote regeneration of aging-associated tissue loss and function. SC-EVs treatment ameliorates brain and peripheral aging, reproductive dysfunctions and inhibits cellular senescence, thereby reversing several aging-related disorders and dysfunctions. The anti-aging therapeutic potential of SC-EVs depends on multiple factors, including the type of stem cells, the age of the source stem cells, and their physiological state. In this review, we briefly describe studies related to the promising effects of SC-EVs against various aging-related pathologies, and then we focus in-depth on the therapeutic benefits of SC-EVs against Alzheimer's disease, one of the most devastating neurodegenerative diseases in elderly individuals. Numerous studies in transgenic mouse models have reported the usefulness of SC-EVs in targeting the pathological hallmarks of Alzheimer's disease, including amyloid plaques, neurofibrillary tangles, and neuroinflammation, leading to improved neuronal protection, synaptic plasticity, and cognitive measures. Cell culture studies have further identified the underlying molecular mechanisms through which SC-EVs reduce amyloid beta (Aβ) levels or shift microglia phenotype from pro-inflammatory to anti-inflammatory state. Interestingly, multiple routes of administration, including nasal delivery, have confirmed that SC-EVs could cross the blood-brain barrier. Due to this, SC-EVs have also been tested to deliver specific therapeutic cargo molecule/s (e.g., neprilysin) to the brain. Despite these promises, several challenges related to quality control, scalability, and biodistribution remain, hindering the realization of the vast clinical promise of SC-EVs.

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.

Effects of transplantation of umbilical cord blood mononuclear cells into the scrotum on sexual function in elderly mice

Aim: This study investigated the effect of allografting umbilical cord blood mononuclear cells (UCBMCs) into the scrotum on sexual function in male elderly mice. Methods: UCBMCs were injected once into the scrotal sheath cavity of elderly mice. Results: The transplanted UCBMCs survived in the scrotal sheath cavity for 1 month. The mice had significantly increased blood testosterone concentrations, cyclic guanosine monophosphate (cGMP) levels and total nitric oxide synthase (T-NOS) activity in the corpus cavernosum and an increase in the number of mouse matings within 30 min (all p = 0.000). Conclusion: Scrotum-implanted UCBMCs improve the sexual function of male elderly mice through testosterone production and the NOS/cGMP pathway, which may provide an innovative transplantation approach for the treatment of erectile dysfunction.

Research progress of extracellular vesicles and exosomes derived from mesenchymal stem cells in the treatment of oxidative stress-related diseases

There is growing evidence that mesenchymal stem cell-derived extracellular vesicles and exosomes can significantly improve the curative effect of oxidative stress-related diseases. Mesenchymal stem cell extracellular vesicles and exosomes (MSC-EVs and MSC-Exos) are rich in bioactive molecules and have many biological regulatory functions. In this review, we describe how MSC-EVs and MSC-Exos reduce the related markers of oxidative stress and inflammation in various systemic diseases, and the molecular mechanism of MSC-EVs and MSC-Exos in treating apoptosis and vascular injury induced by oxidative stress. The results of a large number of experimental studies have shown that both local and systemic administration can effectively inhibit the oxidative stress response in diseases and promote the survival and regeneration of damaged parenchymal cells. The mRNA and miRNAs in MSC-EVs and MSC-Exos are the most important bioactive molecules in disease treatment, which can inhibit the apoptosis, necrosis and oxidative stress of lung, heart, kidney, liver, bone, skin and other cells, and promote their survive and regenerate.

Young Sca-1+ bone marrow stem cell-derived exosomes preserve visual function via the miR-150-5p/MEKK3/JNK/c-Jun pathway to reduce M1 microglial polarization

BACKGROUND

Polarization of microglia, the resident retinal immune cells, plays important roles in mediating both injury and repair responses post-retinal ischemia-reperfusion (I/R) injury, which is one of the main pathological mechanisms behind ganglion cell apoptosis. Aging could perturb microglial balances, resulting in lowered post-I/R retinal repair. Young bone marrow (BM) stem cell antigen 1-positive (Sca-1⁺) cells have been demonstrated to have higher reparative capabilities post-I/R retinal injury when transplanted into old mice, where they were able to home and differentiate into retinal microglia.

METHODS

Exosomes were enriched from young Sca-1⁺ or Sca-1^- cells, and injected into the vitreous humor of old mice post-retinal I/R. Bioinformatics analyses, including miRNA sequencing, was used to analyze exosome contents, which was confirmed by RT-qPCR. Western blot was then performed to examine expression levels of inflammatory factors and underlying signaling pathway proteins, while immunofluorescence staining was used to examine the extent of pro-inflammatory M1 microglial polarization. Fluoro-Gold labelling was then utilized to identify viable ganglion cells, while H&E staining was used to examine retinal morphology post-I/R and exosome treatment.

RESULTS

Sca-1⁺ exosome-injected mice yielded better visual functional preservation and lowered inflammatory factors, compared to Sca-1^-, at days 1, 3, and 7 days post-I/R. miRNA sequencing found that Sca-1⁺ exosomes had higher miR-150-5p levels, compared to Sca-1^- exosomes, which was confirmed by RT-qPCR. Mechanistic analysis found that miR-150-5p from Sca-1⁺ exosomes repressed the mitogen-activated protein kinase kinase kinase 3 (MEKK3)/JNK/c-Jun axis, leading to IL-6 and TNF-α downregulation, and subsequently reduced microglial polarization, all of which contributes to reduced ganglion cell apoptosis and preservation of proper retinal morphology.

CONCLUSION

This study elucidates a potential new therapeutic approach for neuroprotection against I/R injury, via delivering miR-150-5p-enriched Sca-1⁺ exosomes, which targets the miR-150-5p/MEKK3/JNK/c-Jun axis, thereby serving as a cell-free remedy for treating retinal I/R injury and preserving visual functioning.

Effects of stem cell-derived exosome therapy on erectile dysfunction: a systematic review and meta-analysis of preclinical studies

Introduction

Erectile dysfunction (ED) is a common disease among elderly men, and novel therapy methods are needed for drug-refractory ED. As an extracellular vesicle, stem cell-derived exosomes displayed erectile function improvement in rat ED models in some preclinical studies. However, the therapeutic efficacy has not been comprehensively evaluated.

Aim

To study the therapeutic effects of stem cell-derived exosomes on ED in preclinical studies and to investigate the potential mechanisms responsible for the efficacy.

Methods

The systematic literature search was conducted in Web of Science, PubMed, and Embase to retrieve studies utilizing stem cell-derived exosomes for ED treatment. We extracted data of intracavernous pressure/mean artery pressure (ICP/MAP), and cavernosum structural changes in rat ED models before and after stem cell-derived exosome therapy. RevMan 5.3 was used to perform meta-analyses of ICP/MAP and cavernosum microstructural changes. Publication bias was assessed with the Egger test and funnel plot by Stata 15.0 (StataCorp).

Main Outcome Measures

Outcomes included ICP/MAP, smooth muscle, and endothelial markers-such as the ratio of smooth muscle to collagen and the expression of α-SMA (alpha smooth muscle actin), CD31 (cluster of differentiation 31), nNOS and eNOS (neuronal and endothelial nitric oxide synthase), TGF-β1 (transforming growth factor β1), and caspase 3 protein-to evaluate erectile function and microstructural changes. Forest plots of effect sizes were performed.

Results

Of 146 studies retrieved, 11 studies were eligible. Pooled analysis showed that stem cell-derived exosomes ameliorated damaged ICP/MAP (standardized mean difference, 3.68; 95% CI, 2.64-4.72; P < .001) and structural changes, including the ratio of smooth muscle to collagen and the expression of α-SMA, CD31, nNOS, eNOS, TGF-β1, and caspase 3 protein. Subgroup analysis indicated that exosome type and ED model type made no difference to curative effects.

Conclusion

This meta-analysis suggests the therapeutic efficacy of stem cell-derived exosomes for ED. Exosomes may restore erectile function by optimizing cavernosum microstructures.

Stem Cell Therapy for Erectile Dysfunction: A Step towards a Future Treatment

Background: The improvement of absent or partial response in the medical treatment of erectile dysfunction (ED) has led to the development of minimally invasive new treatment modalities in the field of regenerative medicine. Methods: A literature review on stem cell therapy for the treatment of ED was performed. We searched for the terms "erectile dysfunction" and "stem cell therapy" in PubMed and Clinicaltrials.gov. Literature searching was conducted in English and included articles from 2010 to 2022. Results: New treatment modalities for ED involving stem cell therapy are not only conceived with a curative intent but also aim to avoid unnecessary adverse effects. Several sources of stem cells have been described, each with unique characteristics and potential applications, and different delivery methods have been explored. A limited number of interventional studies over the past recent years have provided evidence of a safety profile in their use and promising results for the treatment of ED, although there are not enough studies to generate an appropriate protocol, dose or cell lineage, or to determine a mechanism of action. Conclusions: Stem cell therapy is a novel treatment for ED with potential future applications. However, most urological societies agree that further research is required to conclusively prove its potential benefit.

Erectile dysfunction and exosome therapy

Erectile dysfunction (ED), as a common male disease, can seriously reduce the life quality of men and their partners. With the improvement of human living standards, ED is considered to be an important health issue that plagues men. However, it is difficult for existing therapeutic approaches to meet the needs of all patients, so it is necessary to develop novel treatment strategies. Exosomes, as a class of vesicles secreted by cells with bilayer membrane structure, are involved in various physiological and pathological processes in human body and considered to have great therapeutic potentials. This review summarizes the recent advances on exosome therapy with animal models of ED, and proposes the prospect of future research in order to provide a basis for clinical trials and clinical translation.

Evolution Application of Two-Dimensional MoS2-Based Field-Effect Transistors

High-performance and low-power field-effect transistors (FETs) are the basis of integrated circuit fields, which undoubtedly require researchers to find better film channel layer materials and improve device structure technology. MoS₂ has recently shown a special two-dimensional (2D) structure and superior photoelectric performance, and it has shown new potential for next-generation electronics. However, the natural atomic layer thickness and large specific surface area of MoS₂ make the contact interface and dielectric interface have a great influence on the performance of MoS₂ FET. Thus, we focus on its main performance improvement strategies, including optimizing the contact behavior, regulating the conductive channel, and rationalizing the dielectric layer. On this basis, we summarize the applications of 2D MoS₂ FETs in key and emerging fields, specifically involving logic, RF circuits, optoelectronic devices, biosensors, piezoelectric devices, and synaptic transistors. As a whole, we discuss the state-of-the-art, key merits, and limitations of each of these 2D MoS₂-based FET systems, and prospects in the future.

State of the field: cellular and exosomal therapeutic approaches in vascular regeneration

Pathologies of the vasculature including the microvasculature are often complex in nature, leading to loss of physiological homeostatic regulation of patency and adequate perfusion to match tissue metabolic demands. Microvascular dysfunction is a key underlying element in the majority of pathologies of failing organs and tissues. Contributing pathological factors to this dysfunction include oxidative stress, mitochondrial dysfunction, endoplasmic reticular (ER) stress, endothelial dysfunction, loss of angiogenic potential and vascular density, and greater senescence and apoptosis. In many clinical settings, current pharmacologic strategies use a single or narrow targeted approach to address symptoms of pathology rather than a comprehensive and multifaceted approach to address their root cause. To address this, efforts have been heavily focused on cellular therapies and cell-free therapies (e.g., exosomes) that can tackle the multifaceted etiology of vascular and microvascular dysfunction. In this review, we discuss 1) the state of the field in terms of common therapeutic cell population isolation techniques, their unique characteristics, and their advantages and disadvantages, 2) common molecular mechanisms of cell therapies to restore vascularization and/or vascular function, 3) arguments for and against allogeneic versus autologous applications of cell therapies, 4) emerging strategies to optimize and enhance cell therapies through priming and preconditioning, and, finally, 5) emerging strategies to bolster therapeutic effect. Relevant and recent clinical and animal studies using cellular therapies to restore vascular function or pathologic tissue health by way of improved vascularization are highlighted throughout these sections.

Photoacoustic image-guided corpus cavernosum intratunical injection of adipose stem cell-derived exosomes loaded polydopamine thermosensitive hydrogel for erectile dysfunction treatment

Stem cell-derived exosomes (SC-EXO) was an emerging therapeutic agent in regenerative medicine. Intratunical injection of SC-EXO is considered as a prospective approach for erectile dysfunction (ED) treatment. However, high vascularization of cavernous body makes effective retention a major challenge for SC-EXO intratunical injection. In this study, a Polydopamine nanoparticles (PDNPs) incorporated poly (ethylene glycol)-poly(ε-caprolactone-co-lactide) (PDNPs-PELA) thermosensitive hydrogels were fabricated by a facile in situ polymerization for intratunical administration of adipose stem cell-derived exosomes (EXO). The hydrogels exhibited sol-gel transition at body temperature. Moreover, the in-situ polymerization of PDNPs using poly (ethylene glycol)-poly(ε-caprolactone-co-lactide) (PELA) block copolymer as a template was found to be more stable dispersion in the gel system. After being encapsulated into the hydrogel, EXO shows sustained release behavior within two weeks. In vivo animal experiments revealed that exosomes released from hydrogel lead to the healing of endothelial cells and neurons, increase of the cavity's pressure, thereby restoring the erectile function. In particular, since the PDNPs in thermosensitive gels have excellent photoacoustic performance, the hydrogel can be accurately delivered into the tunica albuginea by the guidance of real-time photoacoustic imaging. These results suggest that the as-prepared PDNPs-PELA has a promising future as an injectable exosome carrier for ED treatment.

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A temperature-sensitive hydrogel with photoacoustic activity was developed for intratunical injection by in-situ polymerization.

•The exosomes encapsulated in the hydrogel can be slowly released and effectively restore damaged nerve and vascular endothelial cells.

•The injection guided by photoacoustic images realizes accurate puncture and real-time filling detection of hydrogel in the corpus cavernosum.

Exosomes as Potential Biomarkers for Erectile Dysfunction, Varicocele, and Testicular Injury

INTRODUCTION

Optimal male reproductive health is dependent upon critical mediators of cell-cell communication: exosomes or extracellular vesicles. These vesicles are nano-sized particles released into a variety of bodily fluids, such as blood and semen. Exosomes are highly stable and can carry genetic and other molecules, including DNA, RNA, and proteins, which provide information about their origin cells.

OBJECTIVE

To identify exosomes as potential biomarkers or therapeutic mediators in male sexual and reproductive disorders like erectile dysfunction (ED), varicocele, and testicular injury.

METHODS

A PubMed search was performed to highlight all articles available relating to exosomes and extracellular vesicles in the pathogenesis of different male sexual and reproductive disorders, and their importance in clinical use as both diagnostic markers and potential therapeutic mediators.

RESULTS

Various male reproductive system disorders, such as ED, varicocele, and testicular injury, are linked to increased or decreased levels of exosomes. Exosomes have a higher number of molecules such as DNA, RNA, and proteins, which can give a more precise and comprehensive result when compared to other biomarkers. Exosomes can be considered as plausible diagnostic biomarkers for male sexual and reproductive diseases, with considerable advantages over other diagnostic procedures such as invasive tissue biopsy. Exosomes can carry cargo such certain drugs and therapeutic molecules making them a promising therapeutic approach. Several studies have begun to test treating various male sexual reproductive disorders with exosomes.

CONCLUSION

Exosomes deliver many components that can regulate gene expression and target signaling pathways. Understanding how extracellular vesicles can be utilized as biomarkers in diagnosing men, particularly those with idiopathic erectile dysfunction, will not only aid in diagnosis but also help with making therapeutic targets. Khodamoradi K, Golan R, Dullea A, et al. Exosomes as Potential Biomarkers for Erectile Dysfunction, Varicocele, and Testicular Injury. Sex Med Rev 2021;XX:XXX-XXX.

Effects of androgen on extracellular vesicles from endothelial cells in rat penile corpus cavernosum

BACKGROUND

The explicit mechanism of erectile dysfunction caused by low androgen status is unknown. It was reported that eNOS was expressed in extracellular vesicles (EVs). Androgen may regulate erectile function by affect the release of EVs from endothelial cells.

OBJECTIVES

To investigate whether androgen affects the production of EVs and nitric oxide (NO) in endothelial cells of rat penile corpus cavernosum.

MATERIALS AND METHODS

Endothelial cells of rat penile corpus cavernosum were isolated and purified from 6-week-old healthy male Sprague Dawley (SD) rats. Endothelial cells were treated with different concentrations of dihydrotestosterone (DHT) in a cell culture medium as follows: no-androgen group (NA group, DHT 0 nmol/L), very-low androgen group (VLA group, DHT 0.1 nmol/L), low androgen group (LA group, DHT 1 nmol/L), and physiological concentrations androgen group (PA group, DHT 10 nmol/L). After 24 h, EVs of supernatant in each group were isolated and identified. The content of EVs and NO in the supernatant and the expression of CD9, CD63, TSG101, and eNOS in EVs were detected.

RESULTS

Positive expression of CD9, CD63, TSG101, and eNOS was found in isolated EVs. The concentration of EVs was lower in the NA group compared with other groups (p < 0.01). The expression of eNOS and the concentration of NO was lower in the NA group than that in other groups (p < 0.05); it was lower in the VLA group than that in the LA group (p < 0.05) and lower in LA group than that in PA group (p < 0.05). When the concentration of DHT in endothelial cell culture medium ranged from 0 to 10 nmol/L, the concentration of DHT was positively correlated with the content of EVs and NO.

CONCLUSION

Decrease in eNOS-expressing EVs is one mechanism of NO reduction in endothelial cells of rat corpus cavernosum caused by low androgen levels.

Beneficial Effects of Human Umbilical Cord Blood Mononuclear Cells on Persistent Erectile Dysfunction After Treatment of 5-Alpha Reductase Inhibitor in Rats

BACKGROUND

Effects of human umbilical cord blood (HUCB) as a valuable source for stem cell-based therapies have not been studied in persistent post-5-alpha reductase inhibitors (5ARI) erectile dysfunction (PPED).

AIM

To determine the effect of intracavernosal injection of HUCB mononuclear cells (MNCs) on ED associated with dutasteride treatment.

METHODS

Twenty five adult male Sprague-Dawley rats were divided into 5 groups (n = 5 per group): (i) control, (ii) 8-week dutasteride (0.5 mg/kg/day, in drinking water), (iii) 12-week dutasteride, (iv) 8-week dutasteride+HUCB-MNCs (1 × 10⁶) and (v) 12-week dutasteride+HUCB-MNCs. HUCB-MNCs were administered intracavernosally after eight weeks of dutasteride treatment. Experiments were performed at 4 weeks following the injection of HUCB-MNCs. Erectile responses and isometric tension of corpus cavernosum (CC) were measured. The protein expressions of phosphodiesterase type 5 (PDE5), endothelial nitric oxide synthase (eNOS), neuronal NOS (nNOS), hypoxia-inducible factor (HIF)-1α and smooth muscle/collagen contents in penile tissue were evaluated by Western blotting, immunohistochemistry, and Masson's trichrome staining, respectively.

MAIN OUTCOME

In vivo erectile function, in vitro relaxant and contractile responses of CC, protein expression and localization of PDE5, eNOS, nNOS, HIF-1α, and smooth muscle content in penile tissue.

RESULTS

Erectile responses in the dutasteride-treated groups were significantly decreased compared with controls (P < .001), persisting after 4-wk of washout. HUCB-MNCs restored diminished intracavernosal pressure responses, acetylcholine-, sodium nitroprusside-, sildenafil-induced relaxations, and increased phenylephrine and electrical field stimulation (EFS)-induced contractions. Decreased EFS-induced relaxations in dutasteride-treated groups were not restored by HUCB-MNCs. Increased PDE5 and reduced nNOS expressions in dutasteride groups were restored by HUCB-MNCs in the 12-week dutasteride group. eNOS and HIF-1α protein expression and serum total and free testosterone  levels were similar among groups. HUCB-MNCs reversed the decreased smooth muscle/collagen ratio in dutasteride-treated tissues. There was a significant increase in PDE5 and HIF-1α staining in 8-week dutasteride animals.

CLINICAL TRANSLATION

This study demonstrates the corrective potential of HUCB-MNCs on some persistent structural and functional deterioration caused by 5ARI treatment in rats, which may encourage further evaluation of HUCB-MNCs in men with PPED.

STRENGTHS AND LIMITATIONS

Therapeutic application of intracavernosal HUCB-MNCs is a novel approach for the rat model of post-5ARI ED. Lack of serum and tissue dihydrotestosterone measurements, vehicle injections and characterization of the cells remain limitations of our study.

CONCLUSION

The persistent ED after prolonged administration of dutasteride in rats is reversed by HUCB-MNC treatment, which holds promise as a realistic therapeutic modality for this type of ED. Oztekin CV, Yilmaz-Oral D, Kaya-Sezginer E, et al. Beneficial Effects of Human Umbilical Cord Blood Mononuclear Cells on Persistent Erectile Dysfunction After Treatment of 5-Alpha Reductase Inhibitor in Rats. J Sex Med 2021;18:889-899.

Exosomes derived from smooth muscle cells ameliorate diabetes-induced erectile dysfunction by inhibiting fibrosis and modulating the NO/cGMP pathway

Erectile dysfunction (ED) is a major health issue among men with diabetes, and ED induced by diabetes mellitus (DMED) is particularly difficult to treat. Therefore, novel therapeutic approaches for the treatment of DMED are urgently needed. Exosomes, nanosized particles involved in many physiological and pathological processes, may become a promising tool for DMED treatment. In this study, we investigated the therapeutic effect of exosomes derived from corpus cavernosum smooth muscle cells (CCSMC‐EXOs) on erectile function in a rat model of diabetes and compared their effect with that of exosomes derived from mesenchymal stem cells (MSC‐EXOs). We incubated labelled CCSMC‐EXOs and MSC‐EXOs with CCSMCs and then observed uptake of the exosomes at different time points using laser confocal microscopy. CCSMC‐EXOs were more easily taken up by CCSMCs. The peak concentration and retention time of labelled CCSMC‐EXOs and MSC‐EXOs in the corpus cavernosum of DMED rats after intracavernous injection were compared by in vivo imaging techniques. Intracavernous injection of CCSMC‐EXOs was associated with a relatively high peak concentration and long retention time. Our data showed that CCSMC‐EXOs could improve erectile function in DMED rats. Meanwhile, CCSMC‐EXOs could exert antifibrotic effects by increasing the smooth muscle content and reducing collagen deposition. CCSMC‐EXOs also increased the expression of eNOS and nNOS, followed by increased levels of NO and cGMP. These findings initially identify the possible role of CCSMC‐EXOs in ameliorating DMED through inhibiting corporal fibrosis and modulating the NO/cGMP signalling pathway, providing a theoretical basis for a breakthrough in the treatment of DMED.

Intracavernous injection of size-specific stem cell spheroids for neurogenic erectile dysfunction: Efficacy and risk versus single cells

BACKGROUND

Intracavernous injection (ICI) of adipose-derived stem cells (ADSCs) has been demonstrated promising for neurogenic erectile dysfunction (ED). However, due to the sponge-like structure of corpus cavernosum (CC) with abundant vessels, ICI was indeed like intravenous injection. Thus, the cell escaping may be a concern of safety and limited therapy, but the issue has not been clearly demonstrated yet.

METHODS

Suspensions of free ADSCs (FAs) and ADSCs-based spheroids (ASs) with suitable size were intracavernously injected at doses of 0.5, 1, 2, or 4 million cells. The cell loss and safety after ICI, erectile function and histopathologic change, etc. were analyzed with multimodality of methods.

FINDINGS

Most FAs escaped from sponge-like CC after ICI due to their small size, weakening stem-cell therapeutic efficacy. Worse still, the escaped cells were shown to cause widespread pulmonary embolism (PE), and even death in some animals. Further, it was founded that the therapeutic effect of FAs may be ascribed to the larger cell clusters which spontaneously aggregated before ICI and were trapped within CC after ICI. In comparison, cell loss and PE were significantly avoided by transplanting ASs. Importantly, better therapeutic outcomes were detected after ICI of ASs when compared to FAs with the same cell number.

INTERPRETATION

Transplantation of size-specific ASs instead of single-cell suspension of FAs for neurogenic ED may be a wiser choice to achieve steady therapeutic outcome and to reduce risks for the future clinical application. FUND: This work was supported by the National Natural Science Foundation of China (81701432) (to Y. Xu). Youth Training Project for Medical science (16QNP129) and Beijing Nova Program of science and technology (Z171100001117115) (to Z. Liu).

Mesenchymal stem cell-derived exosomes ameliorate erection by reducing oxidative stress damage of corpus cavernosum in a rat model of artery injury

Erectile dysfunction (ED) is a common ageing male's disease, and vascular ED accounts for the largest proportion of all types of ED. One of the mechanisms of vascular ED in the clinic is arterial insufficiency, which mainly caused by atherosclerosis, trauma and surgical. Moreover, oxidative stress damage after tissue ischemia usually aggravated the progress of ED. As a new way of acellular therapy, mesenchymal stem cell-derived exosomes (MSC-Exos) have great potential in ED treatment. In the current study, we have explored the mechanism of MSC-Exos therapy in a rat model of internal iliac artery injury-induced ED. Compared with intracavernous (IC) injection of phosphate-buffered saline after artery injury, of note, we observed that both mesenchymal stem cells (MSCs) and MSC-Exos through IC injection could improve the erectile function to varying degrees. More specifically, IC injection MSC-Exos could promote cavernous sinus endothelial formation, reduce the organization oxidative stress damage, and improve the nitric oxide synthase and smooth muscle content in the corpus cavernosum. With similar potency compared with the stem cell therapy and other unique advantages, IC injection of MSC- Exos could be an effective treatment to ameliorate erectile function in a rat model of arterial injury.