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

Intravenously engrafted human multilineage-differentiating stress-enduring (Muse) cells rescue erectile function after rat cavernous nerve injury

OBJECTIVE

To evaluate the effect of intravenous administration of human multilineage-differentiating stress-enduring (Muse) cells on rat postoperative erectile dysfunction (ED) with cavernous nerve (CN) injury without an immunosuppressant.

MATERIALS AND METHODS

Male Sprague-Dawley rats were randomised into three groups after CN crush injury. Either human-Muse cells, non-Muse mesenchymal stem cells (MSCs) (both 1.0 × 105 cells), or vehicle was infused intravenously at 3 h after CN injury without immunosuppressant. Erectile function was assessed by measuring intracavernous pressure (ICP) and arterial pressure (AP) during pelvic nerve electrostimulation 28 days after surgery. At 48 h and 28 days after intravenous infusion of Muse cells, the homing of Muse cells and non-Muse MSCs was evaluated in the major pelvic ganglion (MPG) after CN injury. In addition, expressions of C-X-C motif chemokine ligand (Cxcl12) and glial cell line-derived neurotrophic factor (Gdnf) in the MPG were examined by real-time polymerase chain reaction. Statistical analyses and comparisons among groups were performed using one-way analysis of variance followed by the Tukey test for parametric data and Kruskal-Wallis test followed by the Dunn-Bonferroni test for non-parametric data.

RESULTS

The mean (SEM) ICP/AP values at 28 days were 0.51 (0.02) in the Muse cell group, 0.37 (0.03) in the non-Muse MSC group, and 0.36 (0.04) in the vehicle group, showing a significant positive response in the Muse cell group compared with the non-Muse and vehicle groups (P = 0.013 and P = 0.010, respectively). In the MPG, Muse cells were observed to be engrafted at 48 h and expressed Schwann cell markers S100 (~46%) and glial fibrillary acidic protein (~24%) at 28 days, while non-Muse MSCs were basically not engrafted at 48 h. Higher gene expression of Cxcl12 (P = 0.048) and Gdnf (P = 0.040) was found in the MPG of the Muse group than in the vehicle group 48 h after infusion.

CONCLUSION

Intravenously engrafted human Muse cells recovered rat erectile function after CN injury in a rat model possibly by upregulating Cxcl12 and Gdnf.

Dual Strategy with Adipose-Derived Stem Cells and l-arginine Recovered Cavernosal Functions in a Rat Model of Radical Prostatectomy

As standard therapy for prostate cancer, radical prostatectomy causes cavernous nerve (CN) injury and increases fibrosis and hypoxia-induced penile structural alterations. This study aimed to determine the potential beneficial effects of adipose-derived stem cells (ADSCs) and l-arginine alone or in combination on the penile erection in a rat model of erectile dysfunction caused by bilateral cavernous nerve transection (CNT). Male rats (n = 35) were randomized into five groups: Sham-operated; CNT (4-weeks); CNT plus ADSCs (1 × 106 cells by intracavernosal injection); CNT plus l-arginine (4 weeks, 10 mg/kg/day, oral); and ADSCs combined with l-arginine in CNT. In vivo erectile responses and in vitro relaxant responses were measured. Western blot and immunohistochemistry analyses were used to determine the expression and localization of endothelial nitric oxide synthase, neuronal nitric oxide synthase, transforming growth factor-beta 1, hypoxia-inducible factor-1 alpha (HIF-1α), and apoptosis markers (Bax and Bcl-2). The ratio of smooth muscle to collagen and nerve regeneration were calculated using Masson's trichrome and nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase staining. The combined treatment restored diminished erectile responses, endothelium-dependent acetylcholine, and electrical field stimulation-induced relaxation of the corpus cavernosum in rats with CNT, whereas either monotherapy produced only partial improvements. All treatment regimens restored increases in the protein expression of HIF-1 and Bax in rats with CNT. The decrease in smooth muscle mass and NADPH-diaphorase-positive nerve fibers was partially ameliorated by monotherapy, whereas combined therapy led to recovery. These findings indicate that combined treatment with ADSCs and l-arginine may restore erectile function in rats with CNT by inhibiting hypoxia-induced neurotoxicity and preserving endothelium function and smooth muscle content.

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.

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.

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.

Revisiting the Regenerative Therapeutic Advances Towards Erectile Dysfunction

Erectile dysfunction (ED) is an inability to attain or maintain adequate penile erection for successful vaginal intercourse, leading to sexual and relationship dissatisfaction. To combat ED, various surgical and non-surgical approaches have been developed in the past to restore erectile functions. These therapeutic interventions exhibit significant impact in providing relief to patients; however, due to their associated adverse effects and lack of long-term efficacy, newer modalities such as regenerative therapeutics have gained attention due to their safe and prolonged efficacy. Stem cells and platelet-derived biomaterials contained in platelet-rich plasma (PRP) are thriving as some of the major therapeutic regenerative agents. In recent years, various preclinical and clinical studies have evaluated the individual, as well as combined of stem cells and PRP to restore erectile function. Being rich in growth factors, chemokines, and angiogenic factors, both stem cells and PRP play a crucial role in regenerating nerve cells, myelination of axons, homing and migration of progenitor cells, and anti-fibrosis and anti-apoptosis of damaged cavernous nerve in corporal tissues. Further, platelet-derived biomaterials have been proven to be a biological supplement for enhancing the proliferative and differentiation potential of stem cells towards neurogenic fate. Therefore, this article comprehensively analyzes the progresses of these regenerative therapies for ED.

Effect of HongJing I in Treating Erectile Function and Regulating RhoA Pathway in a Rat Model of Bilateral Cavernous Nerve Injury

HongJing I (HJI), a traditional Chinese herbal formula, has been confirmed to be effective for the clinical treatment of erectile dysfunction (ED). However, the mechanism of action of HJI remains unclear. Here, we aimed to investigate the effect and underlying mechanisms of HJI against ED in a rat model of bilateral cavernous nerve injury (BCNI). Rats were divided into five groups: normal control (NC), BCNI-induced ED model (M), M + low-dose HJI (HL), M + medium-dose HJI (HM), and M + high-dose HJI (HH). All groups were treated with normal saline or the relevant drug for 28 consecutive days after inducing BCNI-ED. At the end of the treatment period, the intracavernous pressure (ICP) was recorded, and histological examination was conducted using Masson's trichrome staining. Immunofluorescence staining and western blotting were applied to detect the changes in fibrosis protein and Ras homolog A (RhoA), Rho-associated protein kinase 1 (ROCK1), and ROCK2 expression. We found that HJI effectively improved the ICP in the treatment groups. In addition, RhoA, ROCK1, and ROCK2 expression levels were increased upon BCNI-ED induction, and HJI successfully inhibited cavernosum fibrosis and the activation of RhoA/ROCK2 signaling. Overall, these results suggest that the effects of HJI in attenuating ED may be caused, at least in part, by the suppression of RhoA/ROCK2 signaling and alleviation of fibrosis. However, the precise mechanism surrounding this requires further investigation in future studies.