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

Bibliometric and Visualization Analysis of Stem Cell Therapy for Erectile Dysfunction

Purpose

As a common male disease, erectile dysfunction (ED) seriously affects the physical and mental health of patients. In recent years, studies have continued to point out the great potential of stem cell therapy (SCT) in the treatment of ED. The purpose of this study is to comprehensively analyze the research of SCT for ED and understand the development trends and research frontiers in this field.

Methods

Publications regarding SCT and ED were retrieved and collected from the Web of Science Core Collection. CiteSpace and VOSviewer software were then utilized for bibliometric and visualization analysis.

Results

A total of 524 publications were eventually included in this study. The annual number of publications in this field was increasing year by year. China and the USA were the two most productive countries. Lin GT, Lue TF and Lin CS, and the University of California San Francisco where they worked were the most productive research group and institution, respectively. The journal with the largest number of publications was The Journal of Sexual Medicine, and the following were mostly professional journals of urology and andrology. Diabetes mellitus-induced ED and cavernous nerve injury-related ED were the two most commonly constructed models of ED in studies. Concerning the types of stem cells, mesenchymal stem cells derived from adipose and bone marrow were most frequently used. Moreover, future research would mainly focus on exosomes, tissue engineering technology, extracorporeal shockwave therapy, and clinical translation.

Conclusion

The research of SCT for ED will receive increasing global attention in the future. Our study provided bibliometric and visualization analysis of published literature, helping researchers understand the global landscape and frontiers in this field. More preclinical and clinical studies should be conducted to more deeply explore the underlying mechanisms of treatment and promote clinical translation.

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.

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.

Nrf2 enhances the therapeutic efficiency of adipose-derived stem cells in the treatment of neurogenic erectile dysfunction in a rat model

BACKGROUND

Erectile dysfunction (ED) caused by intraoperative nerve injury is a major complication of pelvic surgery. Adipose-derived stem cells (ADSCs) have presented therapeutic potential in a rat model of bilateral cavernous nerve injury (BCNI), while inadequate in vivo viability has largely limited their application. Nuclear factor-E2-related Factor (Nrf2) is a key transcription factor that regulates cellular anti-oxidative stress. In this work, we investigated the effect of Nrf2 expression regulation on the viability of ADSCs, and explore its repair potential in a BCNI rat model.

RESULTS

The survival time of tert-Butylhydroquinone (tBHQ)-ADSCs in BCNI model increased obviously. In addition, the tBHQ-ADSCs group presented better restoration of major pelvic ganglion (MPG) nerve contents and fibers, better improvement of erectile function, and less penile fibrosis than the other groups. Moreover, the expression of Nrf2 and superoxide dismutase 1 (SOD1) were higher than those of other groups.

CONCLUSION

Nrf2 could enhance the anti-oxidative stress ability of ADSCs, so as to improve the therapeutic effect of ADSCs on BCNI rat model.

Erectile Dysfunction: Treatments, Advances and New Therapeutic Strategies

Erectile dysfunction (ED) is the inability to get and maintain an adequate penile erection for satisfactory sexual intercourse. Due to its negative impacts on men's life quality and increase during aging (40% of men between 40 and 70 years), ED has always attracted researchers of different disciplines, from urology, andrology and neuropharmacology to regenerative medicine, and vascular and prosthesis implant surgery. Locally and/or centrally acting drugs are used to treat ED, e.g., phosphodiesterase 5 inhibitors (first in the list) given orally, and phentolamine, prostaglandin E1 and papaverine injected intracavernously. Preclinical data also show that dopamine D4 receptor agonists, oxytocin and α-MSH analogues may have a role in ED treatment. However, since pro-erectile drugs are given on demand and are not always efficacious, new strategies are being tested for long lasting cures of ED. These include regenerative therapies, e.g., stem cells, plasma-enriched platelets and extracorporeal shock wave treatments to cure damaged erectile tissues. Although fascinating, these therapies are laborious, expensive and not easily reproducible. This leaves old vacuum erection devices and penile prostheses as the only way to get an artificial erection and sexual intercourse with intractable ED, with penile prosthesis used only by accurately selected patients.

Intracavernous injection of platelet-rich plasma reverses erectile dysfunction of chronic cavernous nerve degeneration through reduction of prostate hyperplasia evidence from an aging-induced erectile dysfunction rat model

Age-induced erectile dysfunction (ED) is a convoluted medical condition, and restoring erectile function (EF) under geriatric conditions is highly complicated. Platelet-rich plasma (PRP) treatment is an inexpensive cell-based therapeutic strategy. We have aimed to restore EF in aged-ED rats with PRP as a therapeutic tool. Male rats were grouped into aged and young according to age. The young rats were considered as normal control (NC) and treated with saline. Aged were further divided into 2 groups and treated with intracavernous (IC) PRP and saline. Treatment was scheduled at the 9th and 10th week for NC and 41th and 42th week for aged-ED rats, with EF analysis scheduled on the 12th week for NC and 44th week for aged-ED rats, respectively. Erectile response, immunofluorescence staining, and electron microscopic analyses were performed. IC PRP treatment effectively reduced prostate hyperplasia (PH). EF response indicated a significant increase in crucial EF parameters in PRP-treated aged-ED rats. Histological evidence denoted a rigid and restored development of tunica adventitia of the dorsal artery, decreased vacuolation of the dorsal penile nerve, and structural expansion of the epineurium. Masson's trichrome and immunostaining results affirmed an elevated expression of α-smooth muscle actin (α-SMA) in the corpus cavernosum (CC). Ultrastructure findings revealed that PRP effectively rejuvenated degenerating nerves, preserved endothelium and adherent junctions of corporal smooth muscle, and restored the axonal scaffolds by upregulating neurofilament-H (NF-H) expression. Finally, PRP enhanced neural stability by enhancing the axonal remyelination processes in aged-ED rats. Hence, PRP treatment was proven to restore EF in aged-ED rats, which was considered a safe, novel, cost-effective, and hassle-free strategy for EF restoration in geriatric patients.

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.