A Systematic Review of Human Trials Using Stem Cell Therapy for Erectile Dysfunction

Restorative therapy clinical trials for erectile dysfunction: a scoping review of endpoint measures

Given the lack of regulatory approval for restorative therapies for the treatment of erectile dysfunction, we hypothesized that clinical trials would vary in methodology and endpoint measurements. Our objective was to analyze methodological approaches and outcome measures of clinical trials evaluating restorative therapies for erectile dysfunction. Data was extracted from clinicaltrials.gov on trials which contained the keywords "erectile dysfunction". We evaluated trials initiated between 2004 and 2021 which listed a restorative therapy intervention. We identified 95 trials investigating energy-based/shockwave therapies (60/95), stem cell therapies (25/95), platelet-based therapies (6/95), and others (4/95). Only 41.1% of the trials evaluated safety. The most common efficacy endpoint was International Index of Erectile Function and Sexual Health Inventory for Men, and only 29.5% utilized penile Doppler. Thirty (31.6%) trials had been completed yet only 3 (3.2%) have published results. We found substantial heterogeneity in methodological approach in the trials. Subjective measures of erectile function were commonly reported, but definitions of inclusion criteria and objective outcome measures were inconsistent. These results provide a basis for the design of future clinical trials to improve the quality of trial data and aid in the development of standardized criteria for erectile dysfunction clinical trials.

Stem-Cell, Shockwave, and Platelet Rich Plasma Therapy for the Treatment of Erectile Dysfunction and Peyronie's Disease: A Survey of Clinics Across the USA

OBJECTIVE

To identify clinics offering off-label therapies for erectile dysfunction (ED) and Peyronie's disease (Pyd) including stem cell, platelet-rich plasma (PRP), and shockwave therapy and to determine the transparency they provided to patients inquiring about these treatment modalities.

METHODS

Clinics were identified in different regions in the US using a systematic search on online website directories and were approached by asking a series of standardized questions regarding the cost of treatment, duration of therapy, the medical staff involved, and patient outcome data. A total of 26 clinics were surveyed for stem cell therapy, 26 for PRP treatment, and 27 for shockwave therapy.

RESULTS

Of the 79 clinics contacted, 93.7% provided some answers to the questions we asked, with a majority offering treatments for both ED and Pyd. The cost of treatment varied widely between clinics. The average cost per stem cell therapy injection was $5291, PRP per injection was $1336, and shockwave therapy per session was $413. A physician was involved in 67% of treatments, and only 6 of 79 clinics reported that a urologist was involved. Over 75% of the clinics reported patient satisfaction following treatment. Durability of benefits to patients ranged from months to years according to the clinics' reports.

CONCLUSION

Our data not only demonstrate the widespread use of off-label therapies for ED and PyD across the United States but also the lack of scientific data to support the claims made to patients. This study highlights the need for more oversight and standardization in novel regenerative therapies for ED and PyD.

Safety and Effectiveness of Repeated Botulinum Toxin A Intracavernosal Injections in Men with Erectile Dysfunction Unresponsive to Approved Pharmacological Treatments: Real-World Observational Data

Intracavernosal injections of botulinum toxin A (BTX/A ic) may be effective for difficult-to-treat erectile dysfunction (ED). This is a retrospective case series study of the effectiveness of repeated off-label BTX/A ic (onabotulinumtoxinA 100U, incobotulinumtoxinA 100U or abobotulinumtoxinA 500U) in men with ED and insufficient response to phosphodiesterase type 5 inhibitors (PDE5-Is) or prostaglandinE1 intracavernosal injections (PGE1 ICIs), defined as an International Index of Erectile Function-Erectile Function domain score (IIEF-EF) < 26 on treatment. Further injections were performed on patients' requests, and the files of men who underwent at least two injections were reviewed. The response to BTX/A ic was defined as the achievement of the minimally clinically important difference in IIEF-EF adjusted to the severity of ED on treatment at baseline. Out of 216 men treated with BTX/A ic and PDE5-Is or PGE1-ICIs, 92 (42.6%) requested at least a second injection. The median time since the preceding injection was 8.7 months. In total, 85, 44 and 23 men received, respectively, two, three and four BTX/A ic. The overall response rate was 77.5%: 85.7% in men with mild ED, 79% for moderate ED and 64.3% for severe ED on treatment. The response increased with repeated injections: 67.5%, 87.5% and 94.7%, respectively, after the second, third and fourth injections. Post-injection changes in IIEF-EF were similar across injections. The time from injection to request for a further injection varied little. Four men reported penile pain at the time of injection (1.5% of all injections), and one experienced a burn at the penile crus. Repeated BTX/A injections combined with PDE5-Is or PGE1-ICIs produced an effective and durable response, with acceptable safety.

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.

Pharmacotherapy vs. minimally invasive therapies as initial therapy for moderate-to-severe benign prostatic hyperplasia: a cost-effectiveness study

BACKGROUND

Recently, minimally invasive therapies (MITs), such as water vapor thermal therapy (WVTT) and prostatic urethral lift (PUL) have become an alternative to surgery or pharmacotherapy to manage benign prostatic hyperplasia (BPH), offering symptom relief with a favorable safety profile. The objective of this study was to evaluate the cost-utility of MITs (WVTT and PUL) compared to pharmacotherapy as initial treatment for patients with moderate-to-severe BPH.

METHODS

In this model-based economic evaluation we simulated BPH progression in men (mean age 65 years, average International Prostate Symptom Score 16.6) over their lifetime and estimated healthcare costs (from the US public payer perspective) per quality-adjusted life year (QALY), discounted at 3% annually. Various clinical scenarios were evaluated given that most men undergo several lifelong therapies up to surgical intervention and potentially thereafter. As such, in the study model men could receive up to three lines of therapy: (1) initial pharmacotherapy with MIT as second-line, and transurethral resection of the prostate (TURP) or pharmacotherapy as third-line; (2) initial MIT (WVTT or PUL) with MIT again, TURP or pharmacotherapy as second-line, and TURP as third-line. Model was populated using data from the published literature. Probabilistic analyses were performed.

RESULTS

Initial treatment with WVTT led to the highest QALYs (13.05) and the lowest cost ($15,461). The cumulative QALYs and lifetime costs were 12.92 QALYs and $20,280 for pharmacotherapy followed by WVTT, 12.87 QALYs and $22,424 for pharmacotherapy followed by PUL, 12.86 QALYs and $20,930 for initial treatment with PUL. In the cost-utility analysis, WVTT as initial treatment dominated all three strategies, i.e., generated more QALYs at a lower cost.

CONCLUSION

WVTT is an effective and cost-saving procedure, and may be an appropriate first-line alternative to pharmacotherapy for moderate-to-severe BPH patients who seek faster improvement and no lifelong commitment to daily medications.

Recent advances in stem cell therapy for erectile dysfunction: a narrative review

INTRODUCTION

While phosphodiesterase type 5 inhibitors (PDE5is) and others are used to treat Erectile dysfunction (ED), many patients are either unresponsive or resistant to it. Stem cell therapy (SCT) is a promising alternative approach. Numerous preclinical trials have demonstrated improved erectile function in animal models using SCT, although the number of clinical trials investigating SCT for men with ED is limited. Nonetheless, findings from human clinical trials suggest that SCT may be a useful treatment option.

AREAS COVERED

Biomedical literature, including PubMed, ClinicalTrials.gov, and European Union Clinical Trials Registry, were analyzed to summarize and synthesize information on stem cell therapy for ED in this narrative review. The achievements in preclinical and clinical evaluations are presented and critically analyzed.

EXPERT OPINION

SCT has demonstrated some benefits in improving erectile function, while further studies are urgently needed. Such studies would provide valuable insights into the optimal use of stem cell therapy and its potential as a therapeutic option for ED. Taking advantage of different mechanisms of action involved in various regenerative therapies, combination therapies such as SCT and low-energy shock waves or platelet-rich plasma may provide a more effective therapy and warrant further research.

Canadian Urological Association guideline: Erectile dysfunction

Erectile dysfunction (ED) impacts the wellness and quality of life of millions of Canadians. An evaluation focused on the identification of reversible and irreversible underlying factors is recommended for patients presenting with ED. Through a shared decision-making model framework, the goal of ED treatment is to improve functional outcomes and enhance sexual satisfaction while minimizing adverse effects associated with treatment. Given that ED is assessed and treated by multiple different types of health practitioners, the purpose of this guideline is to provide the best available evidence to facilitate care delivery through a Canadian lens. After a narrative review of ED assessment and treatment for general readership, five key clinical questions relating to priority areas of ED are assessed using the GRADE and evidence-to-decision-making frameworks.

Effects of Cells Self-aggregation in the Treatment of Neurogenic Erectile Dysfunction With Traditional Single Cell Suspension of Adipose-derived Stem Cells

OBJECTIVE

To clarify the effects of cellular self-aggregation of adipose-derived stem cells (ADSCs) on erectile function (EF).

METHODS

A model of neurogenic erectile dysfunction was performed using bilateral cavernous nerve crush injury in rats. ADSCs suspensions (1 × 10⁶/0.2 ml), were administered via intracavernous injection (ICI) after being allowed to shelve for 0 minute (ICI 0) or 60 minutes (ICI 60) in vitro, as well as cell aggregates isolated from ICI 60 (ICI A). The caudal vein injection group (CVI 60) was used to evaluate whether cell self-aggregation was beneficial to EF when introduced into the peripheral circulation. One day after the transplantation, the distribution of cells was observed. EF and histopathological changes were evaluated after 4 weeks.

RESULTS

Approximately 85% of ADSCs self-aggregated into cell clusters at 60 minutes. The ICI 60 had more significant improvements in EF and more visualized ADSCs retained in the corpus cavernosum (CC) than ICI 0 and CVI 60 (P <.05), but no significant difference between ICI 60 and ICI A. In the CVI 60 group, the cell clusters formed by self-aggregation could hardly reach the CC and were mostly found in lung tissue. Immunofluorescence staining showed increased the content of expressing biomarkers of smooth muscle, nerve within the CC tissue in the ICI groups when compared to the CVI group.

CONCLUSION

ADSCs self-aggregation before ICI may be an influential factor in the treatment of neurogenic erectile dysfunction. Its potential mechanism may be through improving cell retention in the CC.

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.

The use of combination regenerative therapies for erectile dysfunction: rationale and current status

Erectile Dysfunction (ED) is defined as the inability to achieve and maintain an erection sufficient for sexual intercourse. Available treatments for ED provide only symptomatic relief, which is for the most part temporary. Regenerative therapies such as Low Intensity Shockwave, Platelet-Rich Plasma, and Stem Cell therapy can potentially provide a "cure" for ED by reversing the underlying pathology of ED rather than just treating the symptoms. Low Intensity Shockwave therapy is the most evidence based at this point and is thought to act by improving penile blood flow, repairing previous nerve damage, and activating stem cells. Stem Cell therapy takes advantage of the self-replicative potential of stem cells to create new corporal tissue, but also to recruit host cells and angiogenic factors to stimulate endogenous repair. Platelet-Rich Plasma therapy uses concentrated growth factors that already exist within the bloodstream to repair damaged nerves and increase penile blood flow. The use of combination restorative therapy may provide an additive or synergistic benefit greater than any one therapy alone because of its overlapping mechanisms of action on the penis but is a topic that remains to be studied.

A novel flavonoid derivative of icariside II improves erectile dysfunction in a rat model of cavernous nerve injury

BACKGROUND

Icariside II (ICA II), an active flavonoid monomer, has been proven to restore post-prostatectomy erectile dysfunction in rats; however, the high cost of extraction from natural plants limits the application of ICA II.

OBJECTIVE

To investigate the therapeutic effect and possible mechanism of action of YS-10, a new flavonoid compound, which was designed and synthesized based on the structure of ICA II in a rat model in of cavernous nerve injury.

MATERIALS/METHODS

Eight of 32 adult male Sprague-Dawley rats were selected as the normal control (NC) group and received vehicle treatment. The remaining rats were subjected to bilateral cavernous nerve injury (BCNI) and randomized into three groups: BCNI group, BCNI + ICA II group (2.5 mg/kg/day), and BCNI + YS-10 group (2.5 mg/kg/day). The total procedure lasted for 21 days, followed by a washout period of 3 days. All animals were evaluated for erectile function, and tissues were harvested for histopathological analyses.

RESULTS

It was observed that in YS-10 group, the ratio of intracavernous pressure (ICP) to mean arterial pressure (MAP) and the area under the ICP/MAP curve were effectively enhanced. The maximum ICP/MAP increased by 30% in the YS-10 group (0.86 ± 0.085) compared with the BCNI group (0.66 ± 0.058), which is close to 82% of the NC group (1.05 ± 0.033). Histopathological changes demonstrated significant reduction of smooth muscle atrophy, collagen deposition, and endothelial and neural dysfunction after YS-10 treatment, which have no statistical differences compared with ICA II group. Additionally, high-protein expression levels of β-Catenin and cyclin D1 were observed in the treatment groups.

CONCLUSION

YS-10, a novel synthesized flavonoid compound, could effectively improve erectile dysfunction in rats after BCNI by alleviating pathological impairments; this effect may associate with the upregulation of β-Catenin and cyclin D1 in Wnt signaling pathway.

Restorative Therapies for Erectile Dysfunction: Position Statement From the Sexual Medicine Society of North America (SMSNA)

INTRODUCTION

Current non-invasive treatments for erectile dysfunction (ED) include oral medications, intracavernosal injections, and vacuum-assisted devices. Though these therapies work well for many, a subset of patients have contraindications or are unsatisfied with these options. Restorative therapies for ED are a new frontier of treatments focused on regenerating diseased tissue and providing a potential "cure" for ED.

AIM

The aim of this position statement is to examine existing clinical trial data for restorative therapies and identify elements that require further research before widespread adoption.

METHODS

A literature review was performed to identify all clinical trials performed with regenerative therapy for ED. This includes treatments such as stem cell therapy (SCT), platelet rich plasma (PRP), and restorative related technologies like low-intensity shockwave therapy (LiSWT).

MAIN OUTCOME MEASURES

Most clinical trials in restorative therapies were assessed for safety, feasibility, or efficacy. This included recording adverse events, changes in sexual function and erectile function questionnaires, and diagnostics measures.

RESULTS

To date there is an absence of robust clinical data supporting the efficacy of restorative therapies regarding ED, though technologies such as LiSWT have established relative safety.

CONCLUSIONS

Restorative therapies are a promising technology that represents a new frontier of treatment geared towards reversing disease pathology rather than just treating symptoms. However, current published clinical studies are limited. Future work needs to be adequately powered, multi-center, randomized, sham/placebo-controlled trials in well-characterized patient populations to ensure safety and demonstrate efficacy. Until these studies are done, restorative therapies should be reserved for clinical trials and not offered in routine clinical practice. Liu JL, Chu KY, Gabrielson AT, et al. Restorative Therapies for Erectile Dysfunction: Position Statement From the Sexual Medicine Society of North America (SMSNA). J Sex Med 2021;9:100343.

Comparative study of different transplantation methods of adipose tissue-derived stem cells in the treatment of erectile dysfunction caused by cavernous nerve injury

We aimed to compare intracavernosal injection (ICI), tail vein injection (IV), and periprostatic injection (PPI) of adipose-derived stem cells (ADSCs) for their ability to improve erectile function in cavernous nerve injury-induced erectile dysfunction (CNIED) rats and to explore the possible mechanism. Eighty-four male SD rats were divided into the sham group (n = 6), BCNI group (bilateral CN crush injury, n = 6), PBS-ICI group (n = 6), PBS-IV group (n = 6), PBS-PPI group (n = 6), ADSC-ICI group (n = 18), ADSC-IV group (n = 18) and ADSC-PPI group (n = 18). ADSCs were labelled with 5-ethynyl-2'-deoxyuridine (EdU), and six rats each in the ADSC-ICI group, ADSC-IV group, and ADSC-PPI group were sacrificed 2, 7, and 28 days after injection. EdU-labelled ADSCs were tracked by immunofluorescence staining. The intracavernosal pressure (ICP)/mean arterial pressure (MAP) ratio, neuronal nitric oxide synthase (nNOS)-positive nerve fibres in the dorsal penile nerve and the smooth muscle/collagen ratio in the cavernosum between groups were also evaluated. ADSCs can significantly improve erectile function through ICI or IV. The two are similar in efficacy and superior to PPI. The mechanism may be that after CN injury, ADSCs are recruited to around the MPG and secrete a variety of neurotrophic factors that promote the repair of the CN, thereby improving erectile function.

Evaluation of the In Vitro Damage Caused by Lipid Factors on Stem Cells from a Female Rat Model of Type 2 Diabetes/Obesity and Stress Urinary Incontinence

Human stem cell therapy for type 2 diabetes/obesity (T2D/O) complications is performed with stem cell autografts, exposed to the noxious T2D/O milieu, often with suboptimal results. We showed in the Obese Zucker (OZ) rat model of T2D/O that when their muscle-derived stem cells (MDSC) were from long-term T2D/O male rats, their repair efficacy for erectile dysfunction was impaired and were imprinted with abnormal gene- and miR-global transcriptional signatures (GTS). The damage was reproduced in vitro by short-term exposure of normal MDSC to dyslipidemic serum, causing altered miR-GTS, fat infiltration, apoptosis, impaired scratch healing, and myostatin overexpression. Similar in vitro alterations occurred with their normal counterparts (ZF4-SC) from the T2D/O rat model for female stress urinary incontinence, and with ZL4-SC from non-T2D/O lean female rats. In the current work we studied the in vitro effects of cholesterol and Na palmitate as lipid factors on ZF4-SC and ZL4-SC. A damage partially resembling the one caused by the female dyslipidemic serum was found, but differing between both lipid factors, so that each one appears to contribute specifically to the stem cell damaging effects of dyslipidemic serum in vitro and T2D/O in vivo, irrespective of gender. These results also confirm the miR-GTS biomarker value for MDSC damage.

The Effect of Transendocardial Stem Cell Injection on Erectile Function in Men With Cardiomyopathy: Results From the TRIDENT, POSEIDON, and TAC-HFT Trials

BACKGROUND

Despite limited human data, there is a growing interest in the use of stem cell therapy (SCT) for erectile dysfunction (ED).

AIM

To determine the effect of transendocardial stem cell injection on erectile function on men with cardiomyopathy and ED.

METHODS

We used International Index of Erectile Function (IIEF) scores collected from men enrolled in 3 separate randomized controlled trials: Comparison of Allogeneic vs Autologous Bone Marrow-Derived Mesenchymal Stem Cells Delivered by Transendocardial Injection in Patients With Ischemic Cardiomyopathy (POSEIDON), Transendocardial Mesenchymal Stem Cells and Mononuclear Bone Marrow Cells for Ischemic Cardiomyopathy (TAC-HFT), and Dose Comparison Study of Allogeneic Mesenchymal Stem Cells in Patients With Ischemic Cardiomyopathy (TRIDENT). These trials recruited patients with ischemic cardiomyopathy and ejection fraction less than 50%. Inclusion and exclusion criteria were identical in all 3 trials. The primary intervention in these trials included transendocardial stem cell injection of stem cells or placebo via cardiac catheterization. The follow-up period was 1 year. IIEF data were collected at baseline and at multiple time points in each trial.

OUTCOMES

We investigated erectile function over time based on cell dose, cell source (autologous vs allogenic), cell type (mesenchymal stem cells vs bone marrow mononuclear cells), and comparing men who received SCT with those who received placebo.

RESULTS

A total of 36 men were identified with complete IIEF data. 8 men received placebo injection, and 28 received SCT. The median age was 66.5 years. Comorbidities were similar among all men. Analysis was performed on men with ED, defined by an IIEF-EF score of 24 or less. In the placebo and all-comer SCT group, the median IIEF-EF score was 5 [1-8] and 5 [1-15] at baseline and was 3.5 [3-5.8] and 7 [1-18] at 12 months (P > .05). When analyzed by cell dose, the IIEF-EF score in men who received 200 million cells increased significantly over 12 months (14 [4-23] to 20 [15-24.5], P = .014.) Similarly, an autologous cell source resulted in a similar increase from baseline to 12 months (14 [3.8-23.3] to 20 [12-22], P = .030).

CLINICAL IMPLICATIONS

Erectile function may improve after systemic delivery of SCT in men with ischemic cardiomyopathy and at least mild ED.

STRENGTHS & LIMITATIONS

This post hoc analysis is the first to investigate the effect of SCT on erectile function using randomized, placebo-controlled data. Weaknesses include that ED was not a primary end point, and men were not originally recruited based on erectile function.

CONCLUSION

Future trials on systemic delivery of SCT for ED should focus on high cell dose and autologous cell source, as these seem to provide the best response in men with at least mild ED. Ory J, Saltzman RG, Blachman-Braun R, et al. The Effect of Transendocardial Stem Cell Injection on Erectile Function in Men With Cardiomyopathy: Results From the TRIDENT, POSEIDON, and TAC-HFT Trials. J Sex Med 2020;17:695-701.