Therapeutic effects of adipose-derived stem cells-based microtissues on erectile dysfunction in streptozotocin-induced diabetic rats

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.

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.

Advancements in culture technology of adipose-derived stromal/stem cells: implications for diabetes and its complications

Stem cell-based therapies exhibit considerable promise in the treatment of diabetes and its complications. Extensive research has been dedicated to elucidate the characteristics and potential applications of adipose-derived stromal/stem cells (ASCs). Three-dimensional (3D) culture, characterized by rapid advancements, holds promise for efficacious treatment of diabetes and its complications. Notably, 3D cultured ASCs manifest enhanced cellular properties and functions compared to traditional monolayer-culture. In this review, the factors influencing the biological functions of ASCs during culture are summarized. Additionally, the effects of 3D cultured techniques on cellular properties compared to two-dimensional culture is described. Furthermore, the therapeutic potential of 3D cultured ASCs in diabetes and its complications are discussed to provide insights for future research.

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.

Implantation of skin-derived precursor Schwann cells improves erectile function in a bilateral cavernous nerve injury rat model

BACKGROUND

This study was conducted to investigate the therapeutic potential of the skin-derived precursor Schwann cells for the treatment of erectile dysfunction in a rat model of bilateral cavernous nerve injury.

RESULTS

The skin-derived precursor Schwann cells-treatment significantly restored erectile functions, accelerated the recovery of endothelial and smooth muscle tissues in the penis, and promoted nerve repair. The expression of p-Smad2/3 decreased after the treatment, which indicated significantly reduced fibrosis in the corpus cavernosum.

CONCLUSIONS

Implantation of skin-derived precursor Schwann cells is an effective therapeutic strategy for treating erectile dysfunction induced by bilateral cavernous nerve injury.

Vascular endothelium is the basic way for stem cells to treat erectile dysfunction: a bibliometric study

Vascular endothelial is considered to be a key factor in the pathogenesis of erectile dysfunction (ED). The purpose is to reveal the research trend of the field of ED and vascular endothelium. In addition, the goal is to discover the role and mechanism of vascular endothelium in ED. Bibliometrics and visualization methods based on CiteSpace were selected. We conducted the co-authorship analysis of countries, institutions and authors, co-occurrence analysis of keywords, and co-citation analysis of literature and authors through CiteSpace 6.1.R3. 1431 articles from Web of Science Core Collection (WOSCC) were included in the analysis from 1991 to 2022. We found some influential and cutting-edge nodes in each map, including countries, institutions, authors, articles, etc. Stem cell, therapy, oxidative stress, cavernous nerve injury, radical prostatectomy, fibrosis, erectile function, mesenchymal stem cell, and apoptosis may be hot keywords. In conclusion, the efficacy and mechanisms of stem cells and their derivatives in the treatment of diabetes (DM) ED and cavernous nerve injury (CNI) ED are the future research trends. Stem cells therapy for ED is a hot spot in this field, which side notes that stem cells may work mainly through improving endothelial function. Vascular endothelial cells and VEGF may repair nerve and cavernous smooth muscle directly or indirectly, and finally polish up erectile function.

Management of male erectile dysfunction: From the past to the future

Erectile dysfunction is a common disease of the male reproductive system, which seriously affects the life quality of patients and their partners. At present, erectile dysfunction is considered as a social-psychological-physiological disease with complex etiology and various treatment methods. Oral PDE5I is the first-line treatment for erectile dysfunction with the advantages of high safety, good effect and non-invasiveness. But intracavernosal injection, hormonal replacement therapy, vacuum erection device, penile prosthesis implantation can also be alternative treatments for patients have organic erectile dysfunction or tolerance to PDE5I. With the rapid development of technologies, some new methods, such as low-intensity extracorporeal shock wave and stem cell injection therapy can even repair the organic damage of the corpora cavernosa. These are important directions for the treatment of male erectile dysfunction in the future. In this mini-review, we will introduce these therapies in detail.

Intracavernous Injection of Platelet-Rich Plasma Therapy Enhances Erectile Function and Decreases the Mortality Rate in Streptozotocin-Induced Diabetic Rats

Erectile dysfunction (ED) is an agonizing complication of diabetes mellitus (DM) and it is challenging to treat ED in DM patients. Platelet-rich plasma (PRP) is a unique therapeutic strategy comprising intrinsic growth factors. An attempt was made to explore the potentiality of the PRP treatment in DM-induced ED rats in various groups (control, DM-non-ED, DM-ED, and DM-ED treated with PRP). Streptozotocin (STZ) was used to induce DM in rats. The blood glucose levels of the DM rats were maintained at >300 mg/dl. In the 18-week experiment, survival rate, body weight, intracavernous pressure (ICP) variations, and arterial blood pressure were analyzed. The tissue restoration results were validated by histological, immunofluorescence, and transmission electron microscopic analysis. PRP treatment of DM-ED rats significantly increased all parameters of erectile function compared to pre-treatment of PRP and DM-ED treated with vehicle. The histological results revealed that PRP treatment substantially enhanced the regeneration of myelinated nerves and decreased the atrophy of corporal smooth muscle. Notably, the PRP treatment immensely enhanced the survival rate in post-surgery DM-ED rats. These results indicated certain benefits of PRP treatment in delaying damage and preventing post-surgery complications in DM patients. Hence, PRP treatment is a novel multifactorial strategy for DM-ED patients.

Mesenchymal Stem Cells Enhance Vascular Endothelial Growth Factor-A, Endothelial Nitric Oxide Synthetase, and HSP70 Expression in Improving Erectile Dysfunction in Streptozotocin-induced Diabetic Rats

This study investigated the therapeutic role of mesenchymal stem cells (MSCs) on erectile function in a diabetes mellitus erectile dysfunction (DMED) rat model by analyzing the expression of endothelial nitric oxide synthetase (eNOS), vascular endothelial growth factor (VEGF), and the 70 kilodalton heat shock proteins (HSP70). MSCs were isolated from umbilical cords (UCs), and their characteristics identified by flow cytometry and osteogenic differentiation analysis. Thirty 8-week-old rats were divided into four groups: sham, control, T1, and T2. After a 16 h fast, 24 rats were randomly selected and intraperitoneally injected with streptozotocin (STZ) to induce DM. At 8 weeks after STZ injection, rats with DMED were classified into four groups, sham, control group [DMED rats received 500 μL phosphate buffer saline (PBS)]; T1 [DMED rats treated with 500 μL PBS containing 1 × 106 UC-MSCs]; T2 [DMED rats treated with 500 μL PBS containing 2 × 106 UC-MSCs]. Eight weeks after MSCs administration, the rats’ erectile function was measured by cavernous nerve stimulation. The blinded histological and gene expression assessment were used to analyze the eNOS, HSP70 content, and VEGF expression on the penile tissues. MSCs administration, rats in T1 and T2 groups showed a significant enhancement of erectile response that showed a trend of increase of VEGF mRNA level expression was 2.2 ± 0.61 in T2 Group supported with the optimum recovery of eNOS, in which the value of eNOS expression was 20.66% ± 2.32%. While optimum decrease of HSP70 content, the value of HSP70 expression was 15.50% ± 0.90%. IHC results showed that the DMED induction in rats caused a significant decrease of eNOS content in corpus cavernosum tissue. MSCs could ameliorate DMED in rats by increasing VEGF and decreasing HSP70 and eNOS, indicating these cells offer a potential application for DMED patients’ treatment.

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.

Knockdown of miR-423-5p simultaneously upgrades the eNOS and VEGFa pathways in ADSCs and improves erectile function in diabetic rats

This study aimed to explore the possibility of miR‐423‐5p modified adipose‐derived stem cell (ADSCs) therapy on streptozotocin (STZ)‐induced diabetes mellitus erectile dysfunction (DMED) rats. MiR‐423‐5p was knocked down in ADSCs. ADSCs, NC‐miR‐ADSCs and miR‐ADSCs were co‐cultured with human umbilical vein endothelial cells (HUVECs). Normal and high glucose media were supplemented. The supernatant and HUVECs were collected for assessment of eNOS and VEGFa expression, cell proliferation, and apoptosis. HUVECs co‐cultured with ADSCs or miR‐ADSCs exhibited higher eNOS and VEGFa protein expression levels compared to DM groups. MiR‐ADSCs enhanced HUVEC proliferation compared to the ADSCs and NC‐miR‐ADSCs. Lower apoptotic rates were observed when HUVECs were co‐cultured with miR‐ADSCs, compared to ADSCs and NC‐miR‐ADSCs. Fifteen male Sprague‐Dawley (SD) rats aged 12 weeks were induced to develop diabetes mellitus by intraperitoneal injection with STZ, and five healthy SD rats were used as normal controls. Eight weeks after developing diabetes, the rats received ADSCs and miR‐ADSCs via injection into the corpora cavernosa, whereas normal controls and DM controls were injected with saline. Erectile function and histological assessment of penile tissues were performed 8 weeks after injection. The ICP/MAP indicated that erectile function was impaired in the DM rats compared with the normal group. Injection of ADSCs and miR‐ADSCs improved erectile function significantly and was associated with the overexpression of eNOS and VEGFa. MiR‐423‐5p knockdown in ADSCs ameliorated high glucose‐mediated damage to HUVECs and improved erectile function in DM rats by inducing eNOS and VEGFa overexpression, indicating that miR‐423‐5p may be a potential target in the treatment of DMED.

[CRISPR/Cas9-mediated TEAD1 knockout induces phenotypic modulation of corpus cavernosum smooth muscle cells in diabetic rats with erectile dysfunction]

OBJECTIVE

To construct a corpus cavemosum smooth muscle cell (CCSMCs) line with TEAD1 knockout from diabetic rats with erectile dysfunction (ED) using CRISPR/Cas9 technology and explore the role of TEAD1 in phenotypic modulation of CCSMCs in diabetic rats with ED.

OBJECTIVE

Models of diabetic ED were established in male Sprague-Dawley rats by intraperitoneal injection of streptozotocin. CCSMCs from the rat models were primarily cultured and identified with immunofluorescence assay. Three sgRNAs (sgRNA-1, sgRNA-2 and sgRNA-3) were transfected via lentiviral vectors into 293T cells to prepare the sgRNA-Cas9 lentivirus. CCSMCs from diabetic rats with ED were infected by the lentivirus, and the cellular expression of TEAD1 protein was detected using Western blotting. In CCSMCs infected with the sgRNA-Cas9 lentivirus (CCSMCs-sgRNA-2), or the empty lentiviral vector (CCSMCs-sgRNA-NC) and the blank control cells (CCSMCs-CK), the expressions of cellular phenotypic markers SMMHC, calponin and PCNA at the mRNA and protein levels were detected using real-time fluorescence quantitative RT-PCR (qRT-PCR) and Western blotting, respectively.

OBJECTIVE

The primarily cultured CCSMCs from diabetic rats with ED showed a high α-SMA-positive rate of over 95%. The recombinant lentivirus of TEAD1-sgRNA was successfully packaged, and stable TEAD1-deficient CCSMC lines derived from diabetic rat with ED were obtained. Western blotting confirmed that the protein expression of TEAD1 in TEAD1-sgRNA-2 group was the lowest (P < 0.05), and this cell line was used in subsequent experiment. The results of qRT-PCR and Western blotting showed significantly up-regulated expressions of SMMHC and calponin (all P < 0.05) and down-regulated expression of PCNA (all P < 0.05) at both the mRNA and protein levels in TEAD1-deficient CCSMCs from diabetic rats with ED.

OBJECTIVE

We successfully constructed a stable CCSMCs line with CRISPR/Cas9-mediated TEAD1 knockout from diabetic rats with ED. TEAD1 gene knockout can induce phenotype transformation of the CCSMCs from diabetic rats with ED from the synthetic to the contractile type.

Adipose-Derived Stem Cells: Current Applications and Future Directions in the Regeneration of Multiple Tissues

Adipose-derived stem cells (ADSCs) can maintain self-renewal and enhanced multidifferentiation potential through the release of a variety of paracrine factors and extracellular vesicles, allowing them to repair damaged organs and tissues. Consequently, considerable attention has increasingly been paid to their application in tissue engineering and organ regeneration. Here, we provide a comprehensive overview of the current status of ADSC preparation, including harvesting, isolation, and identification. The advances in preclinical and clinical evidence-based ADSC therapy for bone, cartilage, myocardium, liver, and nervous system regeneration as well as skin wound healing are also summarized. Notably, the perspectives, potential challenges, and future directions for ADSC-related researches are discussed. We hope that this review can provide comprehensive and standardized guidelines for the safe and effective application of ADSCs to achieve predictable and desired therapeutic effects.

Co-overexpression of VEGF and GDNF in adipose-derived stem cells optimizes therapeutic effect in neurogenic erectile dysfunction model

Objectives

To evaluate the rapid repair potential of adipose‐derived stem cells (ADSCs) co‐overexpressing VEGF and GDNF on bilateral cavernous nerve injury (BCNI) in rat models. Progressive fibrosis of the penis that occurs shortly after BCNI is a key cause of clinical treatment difficulty of erectile dysfunction (ED). Traditional medications are ineffective for ED caused by BCNI. ADSCs have shown therapeutic effects in animal models, but disappointing in clinical treatment suggests that we should explore optimal treatment of it.

Materials and methods

We extracted ADSCs from rat epididymis. Lentiviral transfection was verified by western blot and immunofluorescence. Thirty‐six SD rats (10 weeks old) were randomly divided into six groups (n = 6 per group): sham surgery, and remaining five BCNI groups transplanted PBS or ADSCs which were genetically modified by vehicle, VEGF (ADSC‐V), GDNF (ADSC‐G), or VEGF&GDNF (ADSC‐G&V) around major pelvic ganglion (MPG). We investigated the therapeutic effects of BCNI rat model which is characterized by ED, penile tissue fibrosis and hypoxia, and lack of nitrogen nerves or vascular atrophy.

Results

Erectile function was almost recovered after 2 weeks of transplantation of ADSC‐G&V, promoted cavernous nerve repair, prevented penile fibrosis and preserving the vascular endothelium, which was significant differences amongst ADSC‐V or ADSC‐G. Moreover, GM‐ADSCs were detected in MPG and penis, indicating that their participation in repair of target organs and transverse nerves.

Conclusions

These promising data indicate that ADSCs co‐overexpressed VEGF and GDNF‐induced synergistic effects, make it a potential tool for recovering of erectile function speedily after BCNI.

Comparison of the therapeutic effects of adipose‑derived and bone marrow mesenchymal stem cells on erectile dysfunction in diabetic rats

The aim of the present study was to compare the effects of adipose‑derived mesenchymal stem cell (ADSC) and bone marrow mesenchymal stem cell (BMSC) transplantation into the corpora cavernosa of diabetic rats with erectile function. ADSCs and BMSCs were isolated and identified by flow cytometry. Rats with streptozocin‑induced diabetes were screened using apomorphine to obtain a rat model of diabetic erectile dysfunction, followed by transplantation of ADSCs and BMSCs into the corpora cavernosa. Two weeks later, the rats were again injected with apomorphine, the intracavernous pressure (ICP) and mean arterial pressure (MAP) of the penile tissue were measured, and the corpus cavernosum tissues were harvested. Angiogenic endothelial nitric oxide synthase (eNOS) expression was detected by western blotting and immunofluorescence analysis. The blood vessels in the corpus cavernosum were observed following hematoxylin and eosin (H&E) staining, and the expression of collagen was detected by Sirius Red staining. The cellular ultrastructure was examined by transmission electron microscopy. Intracavernous injection of ADSCs significantly increased ICP and ICP/MAP. Western blotting and immunofluorescence results revealed that ADSC treatment improved the expression of eNOS in the penile tissue of diabetic rats. The H&E staining results demonstrated that ADSC treatment promoted revascularization of the corpus cavernosum, and the results of Sirius Red staining revealed that ADSC treatment reduced penile collagen in diabetic rats. Transmission electron microscopy examination revealed that the ultrastructure of the tissues in the ADSC‑treated group was more complete compared with that in the untreated diabetic model group. In conclusion, ADSCs were found to be more effective compared with BMSCs in treating diabetes‑related erectile dysfunction.

Isoflurane inhalation anesthesia should be a new requirement in intracavernosal pressure detection-the gold standard of erectile function assessment

Intracavernosal pressure (ICP) is gold standard for the detection of erectile function in animals, but no consensus has yet been achieved on what kind of anesthetic protocol should be applied. A total of 16 adult male Sprague-Dawley rats were randomized into two groups. In group A, chloral hydrate was injected intraperitoneally. Rats in group B were induced in 5% isoflurane for 3 min and then maintained in 1.0–1.5% isoflurane. Mean arterial pressure (MAP), respiratory rate (RR) and heart rate were monitored during all experiments. After ICP detection, tail vein and carotid artery blood were collected. The maximum ICP value, MAP and ICP/MAP ratio in group B was significantly higher than in that of group A. The RR in group A was lower than in that of group B, but the heart rate in group A was higher than in group B. There were no significant differences in both pO₂ and pCO₂ between groups. While the data showed that animals in group A were relatively hypoxemic. Isoflurane inhalation anesthesia in detection of erectile function could offer a relatively more stable physical state than in that under the effect of chloral hydrate intraperitoneal anesthesia. Isoflurane inhalation anesthesia is more suitable for ICP test.

Adipose tissue-derived stem cell therapy for erectile dysfunction in rats: a systematic review and meta-analysis

OBJECTIVE

We aimed to systematically assess the effect of adipose tissue-derived stem cell (ADSC) therapy and its influential factors on the treatment of erectile dysfunction (ED) in rats.

METHODS

Two authors independently searched for published studies through PubMed and EMBASE from study inception until August 31, 2016. A meta-analysis was used to combine the effect estimate from the published studies. A subgroup analysis was performed to identify the effect of some influential factors. The pooled standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated by a fixed-effects or random-effects model analysis.

RESULTS

Twenty studies with a total of 248 rats were included in this meta-analysis. The pooled analysis showed that ADSC therapy significantly increased the ratio of intracavernous pressure and mean arterial pressure (ICP/MAP; SMD 3.46, 95% CI 2.85-4.06; P < 0.001) compared to control therapy. The levels of neuronal nitric oxide synthase (nNOS; SMD 6.37, 95% CI 4.35-8.39; P < 0.001), the cavernous smooth muscle content (CSMC; SMD 3.65, 95% CI 2.65-4.65; P < 0.001), the ratio of cavernous smooth muscle and collagen (CSM/collagen; SMD 4.16, 95% CI 2.59-5.72; P < 0.001), and the cyclic guanosine monophosphate (cGMP; SMD 7.12, 95% CI 2.76-11.48; P = 0.001) were higher following ADSC therapy than following control therapy. Subgroup analysis showed that ADSCs modified by growth or neurotrophic factors significantly recovered erectile function (P < 0.001) compared with ADSC therapy.

CONCLUSION

The adequate data indicated that ADSC therapy recovered erectile function and regenerated cavernous structures in ED rats, and ADSCs modified by some growth and neurotrophic factors accelerated the recovery of erectile function and cavernous structures in ED rats.

Stem Cells in Male Sexual Dysfunction: Are We Getting Somewhere?

INTRODUCTION

Stem cells for sexual disorders are steadily being introduced into clinical trials. Two conditions of importance are the main target for this line of treatment, especially when regarding the wide array of translational and basic science highlighting the potential advantages of regenerative therapy: erectile dysfunction (ED) and more recently Peyronie disease (PD). Cellular therapy offers a treatment modality that might reverse disease progression. It would be used in a curative setting, in contrast to other pharmaceutical agents that are currently available.

AIM

To review basic preclinical studies and recent clinical trials of stem cells on ED and PD.

METHODS

A search of the medical literature for the following terms was performed using PubMed: stem cells, cellular therapy, erectile dysfunction, Peyronie's disease, and clinical trial.

MAIN OUTCOME MEASURES

A non-systematic narrative review and critical reflection on preclinical and clinical studies administering stem cells for ED and PD in animal models and human subjects.

RESULTS

Numerous studies have confirmed the beneficial functional effects of stem cell injection in established animal models on ED and PD. Various stem cell types have been adopted, from embryonic to adult mesenchymal cell types. Each cell type offers distinctive advantages and disadvantages. Diverse administrations of stem cells were investigated, with insignificant variability in the ultimate results. Stem cells appear to have a pronounced paracrine effect, rather than the classic engraftment and differentiation hypothesis. Phase 1 clinical trials using stem cells have not reported any severe adverse events in animals. However, these results cannot be extrapolated to draw any conclusions about efficacy in human patients.

CONCLUSION

Stem cells have an established efficacy in preclinical studies and early clinical trials. Studies are currently being published demonstrating the safety of intrapenile injection of autologous bone marrow- and adipose tissue-derived stem cells. Soebadi MA, Milenkovic U, Weyne E, et al. Stem Cells in Male Sexual Dysfunction: Are We Getting Somewhere? Sex Med Rev 2017;5:222-235.