Reviewing the evidence for shockwave- and cell-based regenerative therapies in the treatment of erectile dysfunction

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.

Microenergy acoustic pulse therapy restores urethral wall integrity and continence in a rat model of female stress incontinence

OBJECTIVE

To determine the outcomes and mechanisms of microenergy acoustic pulse (MAP) therapy in an irreversible rat model of female stress urinary incontinence.

MATERIALS AND METHODS

Twenty-four female Sprague-Dawley rats were randomly assigned into four groups: sham control (sham), vaginal balloon dilation and ovariectomy (VBDO), VBDO + β-aminopropionitrile (BAPN), and VBDO + β-aminopropionitrile treated with MAP (MAP). MAP therapy was administered twice per week for 4 weeks. After a 1-week washout period, all 24 rats were evaluated with functional and histological studies. The urethral vascular plexus was examined by immunofluorescence staining with antibodies against collagen IV and von Willebrand factor (vWF). The urethral smooth muscle stem/progenitor cells (uSMPCs) were isolated and functionally studied in vivo and in vitro.

RESULTS

Functional study with leak point pressure (LPP) measurement showed that the MAP group had significantly higher LPPs compared to VBDO and BAPN groups. MAP ameliorated the decline in urethral wall thickness and increased the amount of extracellular matrix within the urethral wall, especially in the urethral and vaginal elastic fibers. MAP also improved the disruption of the urethral vascular plexus in the treated animals. In addition, MAP enhanced the regeneration of urethral and vaginal smooth muscle, and uSMPCs could be induced by MAP to differentiate into smooth muscle and neuron-like cells in vitro.

CONCLUSION

MAP appears to restore urethral wall integrity by increasing muscle content in the urethra and the vagina and by improving the urethral vascular plexus and the extracellular matrix.

Assessment of the intracavernosal injection platelet-rich plasma in addition to daily oral tadalafil intake in diabetic patients with erectile dysfunction non-responding to on-demand oral PDE5 inhibitors

This study aimed to evaluate the effectiveness of ICI of platelet-rich plasma (PRP) in addition to daily oral tadalafil intake in diabetic erectile dysfunction (ED) patients non-responding to PDE5 inhibitors. Overall, 48 patients complaining of ED non-responding to on-demand PDE5 inhibitors were allocated into 2 equal groups, diabetics and non-diabetics that were given a daily dose of 5 mg tadalafil plus vardenafil 20 mg on demand during the study besides being subjected to 3 doses of ICI of PRP, 4 weeks apart. Responses to on-demand PDE5 inhibitors, International index of erectile function-5 (IIEF-5) score, erection hardness scores (EHS) and pharmaco-dynamic duplex studies were assessed. After PRP injections, 33% and 50% of cases were satisfied with on-demand PDE5 inhibitors, respectively, whereas 41% and 66% of them showed improved EHS response. Compared with baseline scores, the mean IIEF-5 scores were significantly improved after PRP therapy in the diabetic ED group (12.1 vs. 8.04, p = 0.003) as well as in the non-diabetic ED group (14.8 vs. 10.2, p = 0.001) linked to pharmaco-penile duplex readings. Both good and fair diabetic control exhibited significant responses to ICI therapy of PRP compared with bad controlled cases. The significant improvement included; the IIEF-5 score increase (86.7%, 126% vs. 16.1%), improved EHS as well as penile duplex readings. Baseline HbA1C demonstrated a significant negative correlation with IIEF-5 score before (p = 0.019) and after PRP therapy (p = 0.002) respectively. It could be concluded that ICI of PRP could be an effective therapy for treating ED patients non-responding to on-demand oral PDE5 treatment.

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.

Efficacy of Penile Low-Intensity Shockwave Therapy and Determinants of Treatment Response in Taiwanese Patients with Erectile Dysfunction

Background: Erectile dysfunction (ED) remains an emotional wrench to patients and a therapeutic challenge to urologists in andrology clinics worldwide. This is, in part, related to refraction to, or transient effect of phosphodiesterase 5 inhibitors (PDE5i), coupled with patients’ dissatisfaction with this treatment modality. Low-intensity extracorporeal shockwave therapy (Li-ESWT) is an evolving treatment option, with promising curative potential. Current international guidelines are inconclusive, bear weak recommendation strength, and lack ethnogeographic consensus. Objectives: This study evaluated the safety, efficacy, and effect duration of Li-ESWT, as well as exploring disease-associated determinants of treatment success in Taiwanese males with ED. Methods: A cohort of 69 eligible cases treated with 12 sessions of Li-ESWT and followed up for at least 12 months after treatment, between January 2018 and December 2019 at our medical facility, was used. The present single-center, retrospective, non-randomized, single-arm study employed standardized erectile function evaluation indices, namely, the five-item International Index of Erectile Function (IIEF-5) and Erection Hardness Score (EHS). Clinicopathological analyses of selected variables and comparative analyses of time-phased changes in the EF indices relative to baseline values were performed. Evaluation of treatment success was based on minimal clinically important difference (MCID), using a binomial logistic regression model. Results: The median age and duration of ED for our Taiwanese cohort were 55 years and 12 months, respectively, and an average of 31.3% presented with co-morbidities. The mean improvement in IIEF-5, EHS, and quality of life (QoL) domain scores relative to the baseline values was statistically very significant (p < 0.001) at all indicated follow-up time-points. When stratified, Taiwanese patients with severe and moderate ED benefited more from Li-ESWT, compared with those in the mild or mild-to-moderate group. Patients’ pre-Li-ESWT PDE5i response status was not found to significantly influence Li-ESWT response. Univariate analysis showed that age > 45 years (p = 0.04), uncontrolled diabetes mellitus (p = 0.04), and uncontrolled hyperlipidemia (p = 0.01) were strongly associated with Li-ESWT efficacy; however, only age > 45 years (p = 0.04) and uncontrolled hyperlipidemia (p = 0.03) were found to be independent negative predictors of Li-ESWT success by the multivariate logistic model. Follow-up was uneventful, with no treatment-related adverse events or side effects reported. Of the treated patients, 86.1% indicated satisfaction with the treatment regimen, and over 90% indicated they would recommend the same therapy to others. Conclusions: Li-ESWT is a safe and efficacious therapeutic modality for Taiwanese patients with ED. Uncontrolled hyperlipidemia and age > 45 years are independent negative predictors of treatment success for this cohort.

Comparison of the efficacy of low-intensity shock wave therapy and its combination with platelet-rich plasma in patients with erectile dysfunction

We aimed to compare the efficacy of low-intensity shock wave therapy (Li-SWT) alone and its combination with platelet-rich plasma (PRP) in the treatment of patients with erectile dysfunction (ED). Between January 2015 and October 2020, patients who did not benefit from the use of phosphodiesterase type 5 inhibitors (PDE5i; 5 mg/day) for at least 3 months and underwent Li-SWT or Li-SWT with PRP were evaluated retrospectively. There were 93 patients who were subjected to Li-SWT only (Group 1) and 91 patients subjected to Li-SWT with PRP (Group 2). Analysis of the International Index of Erectile Function-Erectile Function Area (IIEF-EF) scores showed a significant increase in both the groups post-treatment (Group 1: from 14.33 ± 4.39 to 23.8 ± 4.37, p = .001; Group 2: from 17.82 ± 3.44 to 26.3 ± 2.55, p = .001). When the increase in the IIEF-EF scores was compared pre- and post-treatment between the groups with respect to the ED grades, there was no statistically significant difference between them. Furthermore, while the intravaginal ejaculatory latency time (IELT) in successfully treated patients of Group 1 remained the same, Group 2 presented 1.5-3.5 times (mean, 2.4) prolongation. Their mean IELT score showed an increase from 2.2 (0.8-3.5) min to 5.3 (2.8-10.5) min. Our study shows that combination treatment of Li-SWT with PRP injections is not only safe for patients with ED, but also effective and safe in prolonging the IELT.