Erectile Dysfunction Treatment Using Stem Cells: A Review

Interrogating erectile dysfunction and evaluating novel therapeutic frontiers, with emphasis on stem cell strategies

Male infertility arises from a complex interplay of factors affecting reproductive organs and various physiological pathways. Among these, erectile dysfunction (ED), a widespread global issue, plays a key role. While existing ED treatments address some aspects, achieving complete reversibility and avoiding side effects remains a challenge. In this context, stem cell therapy emerges as a promising, potentially transformative approach. Preliminary evidence from preclinical animal models and clinical trials highlights stem cell therapy's remarkable efficacy and effectiveness for ED. This novel strategy offers several advantages, including enhanced effectiveness and a reported absence of adverse side effects. This review delves into the causes of male infertility, with a particular focus on ED and its pathophysiology. We explore the current treatment landscape, highlighting therapy's existing strategies' limitations and stem cell therapy's unique potential. By examining relevant preclinical and clinical studies, we provide a comprehensive picture of this innovative approach and its promising future in restoring men's fertility and quality of life.

An overview of the history, current strategies, and potential future treatment approaches in erectile dysfunction: a comprehensive review

INTRODUCTION

Erectile dysfunction (ED) is one of the most common urologic problems in men worldwide, with an approximately high incidence rate, significantly affecting patients' quality of life and their sexual partners.

OBJECTIVES

Due to the association of this disorder with essential diseases such as cardiovascular disease and diabetes, its prevention and treatment are vital for overall human physiologic and psychological health. Along with reviewing the history of treatment and current methods, we seek new approaches to curb this issue in the future.

METHODS

In this review, investigations were based on the focus of each section's content or conducted on an ad hoc basis. Searches were performed in Scopus and PubMed.

RESULTS

In recent years, many treatments for ED have been reported besides oral administration of phosphodiesterase 5 inhibitors such as sildenafil and tadalafil (approved by the Food and Drug Administration). Common oral medications, intracavernous injections, herbal therapies (eg, herbal phosphodiesterase 5 inhibitors), and topical/transdermal medications are routine ED treatment approaches. Moreover, some novel medications are innovative candidates for completing ED's treatment protocols: stem cell injection, low-intensity extracorporeal shock wave therapy, platelet-rich plasma injection, gene therapy, amniotic fluid matrices, rho-kinase inhibitors, melanocortin receptor antagonists, maxi-K channel activators (ie, large-conductance calcium-activated potassium channels), guanylate cyclase activators, and nitric oxide donors.

CONCLUSION

Due to the importance of this complicated problem in men's society, a faster course of treatment trends toward new methods is needed to increase efficiency. Combining the mentioned treatments and attentively examining their efficacy through programmed clinical trials can be a big step toward solving this global problem.

Application of Stem Cell in Human Erectile Dysfunction - A Systematic Review

Introduction

Erectile dysfunction is a health problem that arises from various conditions and causes an impaired quality of life with a significant health burden. Regenerative and stem cell therapies are some of the potential treatments for erectile dysfunction. This study aimed to review the available information in the literature regarding the use of stem cells in the treatment of erectile dysfunction.

Methods

This study is a systematic review conducted based on the PubMed, Google Scholar, Cochrane, and DOAJ databases. Literature searching was conducted in English and included articles from 2000 to 2020.

Results

The result was a total of 318 articles. Following the elimination process, 9 articles remained in the final analysis. The analyzed studies included 164 patients with erectile dysfunction with various medical conditions. Several stem cell types have been used for treating erectile dysfunction, including mesenchymal stem cell, placental matrix-derived stem cell, mesenchymal stem cell-derived exosome, adipose-derived stem cell, bone marrow-derived mononuclear stem cell, and umbilical cord blood stem cell. Generally, stem cell therapy showed a good efficacy and safety profile, although not enough studies on the protocol, dosage, and mechanism of action.

Conclusion

Stem cell therapy has a good therapeutic potential in erectile dysfunction, the available data from the literature could be the base of usage of stem cells in the treatment of erectile dysfunction although need more research for broader usage.

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.

Pathological Significance of Macrophages in Erectile Dysfunction Including Peyronie's Disease

Erectile function is regulated by complex mechanisms centered on vascular- and nerve-related systems. Hence, dysregulation of these systems leads to erectile dysfunction (ED), which causes mental distress and decreases the quality of life of patients and their partners. At the molecular level, many factors, such as fibrosis, lipid metabolism abnormalities, the immune system, and stem cells, play crucial roles in the etiology and development of ED. Although phosphodiesterase type 5 (PDE5) inhibitors are currently the standard treatment agents for patients with ED, they are effective only in a subgroup of patients. Therefore, further insight into the pathological mechanism underlying ED is needed to discuss ED treatment strategies. In this review, we focused on the biological and pathological significance of macrophages in ED because the interaction of macrophages with ED-related mechanisms have not been well explored, despite their important roles in vasculogenic and neurogenic diseases. Furthermore, we examined the pathological significance of macrophages in Peyronie’s disease (PD), a cause of ED characterized by penile deformation (visible curvature) during erection and pain. Although microinjury and the subsequent abnormal healing process of the tunica albuginea are known to be important processes in this disease, the detailed etiology and pathophysiology of PD are not fully understood. This is the first review on the pathological role of macrophages in PD.

Stem cell therapy and diabetic erectile dysfunction: A critical review

Erectile dysfunction (ED) has been identified as one of the most frequent chronic complications of diabetes mellitus (DM). The prevalence of ED is estimated to be about 67.4% in all DM cases worldwide. The pathophysiological process leading to ED involves endothelial, neurological, hormonal, and psychological factors. In DM, endothelial and neurological factors play a crucial role. Damages in the blood vessels and erectile tissue due to insulin resistance are the hallmark of ED in DM. The current treatments for ED include phosphodiesterase-5 inhibitors and penile prosthesis surgery. However, these treatments are limited in terms of just relieving the symptoms, but not resolving the cause of the problem. The use of stem cells for treating ED is currently being studied mostly in experimental animals. The stem cells used are derived from adipose tissue, bone, or human urine. Most of the studies observed an improvement in erectile quality in the experimental animals as well as an improvement in erectile tissue. However, research on stem cell therapy for ED in humans remains to be limited. Nevertheless, significant findings from studies using animal models indicate a potential use of stem cells in the treatment of ED.

A case report of pudendal arteries angioplasty with sirolimus drug-coated balloon and drug-eluting stent associated with intracavernous autologous peripheral blood mononuclear cells injection for untreatable vasculogenic erectile dysfunction

Background

Erectile dysfunction (ED) is a prevalent health problem that seriously impacts men's quality of life. The potential treatment of ED by percutaneous approach has emerged with valid angiographic results and a significant improvement in symptoms and quality of life. In addition, cell-based regenerative therapies aiming at enhancing neovascularization have been successfully performed with peripheral blood mononuclear cells (PBMNCs) in diabetic patients affected by critical limb ischaemia.

Case summary

We report a case of a young insulin dependent (ID) diabetic patients who suffered of severe vasculogenic erectile dysfunction associated with a poor response for more than 1 year to oral phosphodiesterase-5 inhibitors (PDE5i) and intracavernous (IC) phosphodiesterase type 1 (PDE1) therapy. At selective angiography of the pelvic district, a severe atherosclerotic disease of the internal iliac and pudendal artery was evident with absence of distal vascularization of the cavernous bodies. The patient was treated by mechanical revascularization with drug-coated balloon and drug-eluting stent placement associated with IC injection of autologous PBMNCs. Immediate and 1-year clinical and angiographic follow-up are described.

Discussion

Percutaneous revascularization with drug-coated balloon and drug-eluting stent associated with IC autologous PBMNCs cells injection is a safe and effective procedure to restore normal erectile function in diabetic patients affected by severe vasculogenic ED not responding to conventional oral drug therapies.

Advances in Nanoparticle Delivery System for Erectile Dysfunction: An Updated Review

INTRODUCTION

The use of current available treatment for male erectile dysfunction (ED) has some limitations that are related to efficacy and adverse effects. Nanotechnology has been used as a new tool in medicine to improve these limitations and new medications potentially to alleviate and cure ED.

AIM

To review the currently literature on new nano medications for ED based on scientific and clinical studies, efficacy, safety, mechanisms of action, and to identify gaps for future research.

METHODS

A comprehensive literature review was conducted via Google Scholar, Science Direct, and PubMed on English publications using different keywords such as "erectile dysfunction", "emerging treatments", "nanotechnology", and "herbal medicine". The retrieved papers were organized into groups according to the sections covered in this review paper.

MAIN OUTCOMES MEASURES

We reviewed novel ED treatments such as nanotechnological phosphodiesterase inhibitors, papaverine hydrochloride, sialorphin, adipose tissue-derived stem cells, sonic hedgehog, and herbal medicine.

RESULTS

Numerous preclinical studies have addressed novel phosphodiesterase 5 inhibitors nanoparticle, and their recent delivery systems. Nitric oxide, sialorphin, sonic hedgehog, and herbal medicine loaded nanoparticles and nano adipose tissue-derived stem cells as a potential new treatment for ED. In addition, papaverine-containing nanoparticles have been reported. A limited number of randomized clinical studies have determined the mechanism of these treatments.

CONCLUSION

A literature review on the application of nanotechnology in ED therapy was successfully conducted. New nano medications are promising to treat ED. However, further studies are warranted to further assess their efficacy and safety. Masuku NP, Unuofin JO, Lebelo SL. Advances in Nanoparticle Delivery System for Erectile Dysfunction: An Updated Review. Sex Med 2021;XX:XXXXXX.