Adipose Tissue-Derived Stem Cells for the Treatment of Erectile Dysfunction

Adipose Tissue Derivatives in Peripheral Nerve Regeneration after Transection: A Systematic Review

INTRODUCTION

Peripheral nerve injury (PNI) is increasingly prevalent and challenging to treat despite advances in microsurgical techniques. In this context, adipose tissue derivatives, such as adipose-derived stem cells, nanofat, and stromal vascular fraction have been gaining attention as potential allies in peripheral nerve regeneration.

OBJECTIVES

This study aims to explore the use of adipose tissue derivatives in nerve regeneration following peripheral nerve transection in murine models. Thus, we assess and synthesize the key techniques and methods used for evaluating the obtained nerve regeneration to guide future experimental research and clinical interventions.

METHODOLOGY

A systematic review was conducted in February 2024, adhering to the Cochrane and PRISMA 2020 guidelines, using the PubMed, SciELO, and LILACS databases. The focus was on experimental studies involving adipose tissue derivatives in nerve regeneration in animal models post-transection. Only experimental trials reporting nerve regeneration outcomes were included; studies lacking a comparator group or evaluation methods were excluded.

RESULTS

Out of 273 studies initially identified from MEDLINE, 19 were selected for detailed analysis. The average study included 32.5 subjects, with about 10.2 subjects per intervention subgroup. The predominant model was the sciatic nerve injury with a 10 mm gap. The most common intervention involved unprocessed adipose-derived stem cells, utilized in 14 articles.

CONCLUSIONS

This review underscores the significant potential of current methodologies in peripheral nerve regeneration, particularly highlighting the use of murine models and thorough evaluation techniques.

MicroRNA-145 Gene Modification Enhances the Retention of Bone Marrow-Derived Mesenchymal Stem Cells within Corpus Cavernosum by Targeting Krüppel-Like Factor 4

PURPOSE

The poor retention and ambiguous differentiation of stem cells (SCs) within corpus cavernosum (CC) limit the cell application in erectile dysfunction (ED). Herein, the effects and mechanism of microRNA-145 (miR-145) gene modification on modulating the traits and fate of bone marrow-derived mesenchymal stem cells (BMSCs) were investigated.

MATERIALS AND METHODS

The effects of miR-145 on cell apoptosis, proliferation, migration, and differentiation were determined by flow cytometry, cell counting kit-8, transwell assays and myogenic induction. Then, the age-related ED rats were recruited to four groups including phosphate buffer saline, BMSC, vector-BMSC, overexpressed-miR-145-BMSC groups. After cell transplantation, the CC were harvested and prepared to demonstrate the retention and differentiation of BMSCs by immunofluorescent staining. Then, the target of miR-145 was verified by quantitative real-time polymerase chain reaction and immunohistochemical. After that, APTO-253, as an inducer of Krüppel-like factor 4 (KLF4), was introduced for rescue experiments in corpus cavernosum smooth muscle cells (CCSMCs) under the co-culture system.

RESULTS

In vitro, miR-145 inhibited the migration and apoptosis of BMSCs and promoted the differentiation of BMSCs into smooth muscle-like cells with stronger contractility. In vivo, the amount of 5-ethynyl-2'-deoxyuridine (EdU)+cells within CC was significantly enhanced and maintained in the miR-145 gene modified BMSC group. The EdU/CD31 co-staning was detected, however, no co-staining of EdU/α-actin was observed. Furthermore, miR-145, which secreted from the gene modified BMSCs, dampened the expression of KLF4. However, the effects of miR-145 on CCSMCs could be rescued by APTO-253.

CONCLUSIONS

Overall, miR-145 modification prolongs the retention of the transplanted BMSCs within the CC, and this effect might be attributed to the modulation of the miR-145/KLF4 axis. Consequently, our findings offer a promising and innovative strategy to enhance the local stem cell-based treatments.

Poly-L-lactic acid/gelatin electrospun membrane-loaded bone marrow-derived mesenchymal stem cells attenuate erectile dysfunction caused by cavernous nerve injury

Radical prostatectomy (RP) can cause neurogenic erectile dysfunction (ED), which negatively affects the quality of life of patients with prostate cancer. Currently, there is a dearth of effective therapeutic strategies. Although stem cell therapy is promising, direct cell transplantation to injured cavernous nerves is constrained by poor cell colonization. In this study, poly-L-lactic acid (PLLA)/gelatin electrospun membranes (PGEM) were fabricated to load bone marrow-derived mesenchymal stem cells (BM-MSCs) as a patch to be placed on injured nerves to alleviate ED. This study aimed to establish a promising and innovative approach to mitigate neurogenic ED post-RP and lay the foundation for modifying surgical procedures. Electrospinning and molecular biotechnology were performed in vitro and in vivo, respectively. It was observed that PGEM enhanced the performance of BM-MSCs and Schwann cells due to their excellent mechanical properties and biocompatibility. The transplanted PGEM and loaded BM-MSCs synergistically improved bilateral cavernous nerve injury-related ED and the corresponding histopathological changes. Nevertheless, transplantation of BM-MSCs alone has been verified to be ineffective. Overall, PGEM can serve as an ideal carrier to supply a more suitable survival environment for BM-MSCs and Schwann cells, thereby promoting the recovery of injured cavernous nerves and erectile function.

Cavernous Nerve Injury Resulted Erectile Dysfunction and Regeneration

Erectile dysfunction (ED) is an important cause of reduced quality of life for men and their partners. Recent studies have found that cavernous nerve injury (CNI) during prostate cancer surgery and other pelvic surgery results in medically induced CNIED in more than 80% of patients. The efficacy of first- and second-line treatment options for ED is poor. A great deal of research has been devoted to exploring new methods of neuroprotection and nerve regeneration to save erectile function in patients with CNIED, especially in patients with cavernous nerve injury after prostate cancer surgery. In addition, such as neuromodulatory proteins, proimmune ligands, gene therapy, stem cell therapy, and the current cutting-edge low-energy shock wave therapy have shown advantages in basic research and limited clinical studies. In the context of today's modern medicine, these new therapeutic techniques are expected to be new tools in the treatment of cavernous nerve injury erectile dysfunction. This article presents the main causes, mechanisms, and treatment of cavernous nerve injury erectile dysfunction and combines them with new treatment strategies.

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.

A systematic review of intracavernosal injection of mesenchymal stem cells for diabetic erectile dysfunction

BACKGROUND As current erectile dysfunction (ED) treatments are limited, other treatment such as stem cells should be explored. Hence, this study aimed to review the sources, method of administration, and therapeutic effect of mesenchymal stem cells (MSCs) for diabetic ED treatment. METHODS All relevant articles regarding the use of MSCs for diabetic ED were searched in PubMed and Google Scholar databases from December 15, 2019 to January 1, 2020 published in the past 10 years. The keywords were “mesenchymal stem cells” and “diabetic ED”. The selection and critical appraisal of the studies were discussed. Diabetic ED was evaluated for functional and structural outcome. Functional outcome in animal studies was assessed by intracavernosal pressure/mean arterial pressure (ICP/MAP) ratio, meanwhile the structural outcome was done microscopically. In human study, the assessments were done using international index of erectile function score (IIEF-5) to erection hardness score and penile Doppler ultrasonography. RESULTS There were 10 animal studies and 3 human studies. The studies used MSCs from adipose (n = 6), bone marrow (n = 4), placenta (n = 1), umbilical cord (n = 1), and muscle tissue (n = 1). The MSCs were administrated through intracavernosal injection in all studies. In all animal studies, functional outcome was improved, shown in higher ICP/MAP ratio. Microscopically, there were an increase of cavernosal endothelial cells, vascular endothelial growth factor, nitric oxide synthase, and smooth muscle cells. In human studies, IIEF-5 and erection hardness score were improved. Peak systolic velocity was also higher. CONCLUSIONS MSCs may be a promising therapy for diabetic ED; however, long-term safety concerns still need further investigations.

Exosomes from adipose‑derived stem cells promote chondrogenesis and suppress inflammation by upregulating miR‑145 and miR‑221

Osteoarthritis (OA) is one of the most prevalent joint disorders globally. Patients suffering from OA are often obese and adiposity is linked to chronic inflammation. In the present study, the potential of using exosomes isolated from adipose‑derived stem cells (ADSCs) as a therapeutic tool for reducing chronic inflammation and promoting chondrogenesis was investigated using patient‑derived primary cells. First, it was tested whether patient‑derived ADSCs could differentiate into chondrogenic and osteogenic lineages. The ADSCs were then used as a source of exosomes. It was found that exosomes isolated from ADSCs, when co‑cultured with activated synovial fibroblasts, downregulated the expression of pro‑inflammatory markers interleukin (IL)‑6, NF‑κB and tumor necrosis factor‑α, while they upregulated the expression of the anti‑inflammatory cytokine IL‑10; without exosomes, the opposite observations were made. In addition, inflammation‑inflicted oxidative stress was induced in vitro by stimulating chondrocytes with H2O2. Treatment with exosomes protected articular chondrocytes from H2O2‑induced apoptosis. Furthermore, exosome treatment promoted chondrogenesis in periosteal cells and increased chondrogenic markers, including Collagen type II and β‑catenin; inhibition of Wnt/β‑catenin, using the antagonist ICG‑001, prevented exosome‑induced chondrogenesis. Periosteal cells treated with exosomes exhibited higher levels of microRNA (miR)‑145 and miR‑221. The upregulation of miR‑145 and miR‑221 was associated with the enhanced proliferation of periosteal cells and chondrogenic potential, respectively. The present study provided evidence in support for the use of patient‑derived exosomes, produced from ADSCs, for potential chondrogenic regeneration and subsequent amelioration of osteoarthritis.

IcarisideII facilitates the differentiation of ADSCs to SCs via let-7i/STAT3 axis to preserve erectile function

BACKGROUND

IcarisideII (ICAII) could promote the differentiation of adipose tissue-derived stem cells (ADSCs) to Schwann cells (SCs), leading to improvement of erectile function (EF) and providing a realistic therapeutic option for the treatment of erectile dysfunction (ED). However, the underlying molecular mechanisms of ADSCs and ICAII in this process remain largely unclear.

METHODS

ADSCs were treated with different concentrations of ICAII. Cell proliferation was determined by MTT assay. qRT-PCR and western blot were performed to detect expressions of SCs markers, signal transducer and activator of transcription-3 (STAT3), and microRNA-let-7i (let-7i). Luciferase reporter assay was conducted to verify the regulatory relationship between let-7i and STAT3. The detection of intracavernosal pressure (ICP) and the ratio of ICP/mean arterial pressure (MAP) were used to evaluate the EF in bilateral cavernous nerve injury (BCNI) rat models.

RESULTS

ICAII promoted cell proliferation of ADSCs in a dose-dependent manner. The mRNA and protein levels of SCs markers were increased by ICAII treatment in a dose-dependent manner in ADSCs. Moreover, let-7i was significantly decreased in ICAII-treated ADSCs and upregulation of let-7i attenuated ICAII-induced promotion of SCs markers. In addition, STAT3 was a direct target of let-7i and upregulated in ICAII-treated ADSCs. Interestingly, overexpression of STAT3 abated the let-7i-mediated inhibition effect on differentiation of ADSCs to SCs and rescued the ICAII-mediated promotion effect on it. Besides, combination treatment of ADSCs and ICAII preserved the EF of BCNI rat models, which was undermined by let-7i overexpression.

CONCLUSION

ICAII was effective for preserving EF by promoting the differentiation of ADSCs to SCs via modulating let-7i/STAT3 pathway.

Stem-cell regenerative medicine as applied to the penis

PURPOSE OF REVIEW

Tissue engineering and regenerative medicine has emerged as a new scientific interdisciplinary field focusing on developing new strategies to repair or recreate tissues and organs. This review gathers findings on erectile dysfunction and, Peyronie's disease from recent preclinical and clinical studies under heading of stem-cell regenerative medicine.

RECENT FINDINGS

Over the last 2 years, preclinical studies on rat models demonstrated the tangible beneficial role of stem cells and stromal vascular fraction in the context of preventing fibrosis and restoring erectile function in different animal models of Erectile dysfunction and Peyronie's disease. There are not solid evidences in the clinical settings.

SUMMARY

Large randomized, double blind clinical trials are needed to prove the efficacy of stem-cell therapy on human patients. Owing to the lack of solid evidences, the stem-cell therapy should be only administrated in a clinical research setting.

Emerging nonsurgical and surgical techniques to treat erectile dysfunction: A systematic review of treatment options and published outcomes

Erectile dysfunction (ED) is one of the most common causes of morbidity in male patients, with a prevalence of 50-60% in men aged 40-70 years. EDs may be caused by physical or psychological trauma, the former of which may be treatable through surgical intervention. Physical trauma may be further categorized as vasculogenic, neurogenic, or idiopathic in nature. Although many patients do not respond well to nonsurgical treatment options, few opt for surgical intervention. This is likely due to the difficulty of the procedures, as well as relatively low historical success rates. As such, a systematic review of the literature was performed to identify novel surgical interventions for ED. A total of 19 manuscripts were included in this review, representing data of three minimally invasive approaches to ED treatment and seven novel surgical techniques. The data revealed compelling evidence in support of microsurgical treatments for ED - namely, microvascular arterial bypass penile revascularization surgery (MABS) and cavernous nerve graft reconstruction. Nerve grafts varied, with the use of end-to-side ilioinguinal, genitofemoral, and sural grafts, all demonstrating high rates of success. Furthermore, minimally invasive botulinum toxin (BoNT-A) treatment and adipose-derived stem cell (ADSC) therapy have shown extreme promise in rat models; with BoNT-A treatment entering phase II human clinical trials this year. Many of the surgical methods investigated in this review are microsurgical interventions that demonstrate high rates of success in patients with neurogenic or vasculogenic ED. As such, microsurgeons are uniquely trained and positioned to be of value to ED treatment.

Advances in stem cell therapy for erectile dysfunction

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Stem cell therapy in erectile dysfunction: science fiction or realistic treatment option?

Stem cell therapy has become a subject of great interest to researchers worldwide. One of the medical conditions being studied for possible treatment with the use of stem cells is erectile dysfunction, and particularly organic and post-radical prostatectomy erectile dysfunction. However, is stem cell therapy a viable treatment option for erectile dysfunction? The current body of literature provides a wide array of clinical trials performed on animal models simulating different types of human erectile dysfunction. Unfortunately, only a handful of studies have been performed on human patients and almost all of them were phase 1 studies limited by the small sample size. This review aims to summarize the available evidence on the use of stem cell therapy for the treatment of erectile dysfunction and also to provide an overview of upcoming and ongoing clinical trials in this field.

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

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

Neuroprotective and Nerve Regenerative Approaches for Treatment of Erectile Dysfunction after Cavernous Nerve Injury

Erectile dysfunction (ED) is a significant cause of reduced quality of life in men and their partners. Cavernous nerve injury (CNI) during pelvic surgery results in ED in greater than 50% of patients, regardless of additional patient factors. ED related to CNI is difficult to treat and typically poorly responsive to first- and second-line therapeutic options. Recently, a significant amount of research has been devoted to exploring neuroprotective and neuroregenerative approaches to salvage erectile function in patients with CNI. In addition, therapeutic options such as neuregulins, immunophilin ligands, gene therapy, stem cell therapy and novel surgical strategies, have shown benefit in pre-clinical, and limited clinical studies. In the era of personalized medicine, these new therapeutic technologies will be the future of ED treatment and are described in this review.

Stem cell therapy for the treatment of Peyronie's disease

INTRODUCTION

Like other fibrotic diseases, the cause of Peyronie's disease (PD) is still obscure. Since there is now increasing evidence for the role of Mesenchymal Stem Cells (MSCs) as potential treatment to fibrosis, it is crucial to determine their possible efficacy in the treatment of PD. Areas covered: In this review, the authors summarize the emerging data and published studies regarding the use of SCs for the treatment of PD. The authors provide particular focus on the three-first experimental studies for the use of SCs in rat models as well as the sole two studies undertaken in humans. Expert opinion: It seems evident in experimental settings that SCs in general (Adipose Derived SCs in particular) provide a feasible, safe and effective therapy for PD. The potential limits of the rat models used initially have been somewhat overcome with the inception of studies in men. However, further prospective studies are needed in humans to further elucidate the therapeutic potential of stem cell therapy in PD.