Effect of low-energy shockwave therapy on angiogenic factors in the penile tissue of diabetic rats

Low-intensity extracorporeal shockwave therapy for diabetic men with erectile dysfunction: A systematic scoping review

BACKGROUND

Erectile dysfunction (ED) is a very common complication in men with diabetes mellitus (DM). Low-intensity extracorporeal shockwave therapy (Li-ESWT) offers a promising nonsurgical treatment option for ED. A systematic scoping review investigating the outcomes of Li-ESWT in diabetic men with ED has not yet been performed.

OBJECTIVES

To systematically review animal and clinical studies related to the use of Li-ESWT for treatment of DM-related ED.

DATA SOURCES

PubMed, Embase, The Cochrane Library, Scopus, and Web of Science were searched, unrestricted by dates or study design.

MATERIALS AND METHODS

We included qualitative studies, quantitative studies, primary research studies, meta-analyses, and research letters written in English. Full text reviewing was completed in all animal and human studies discussing Li-ESWT for the treatment of ED in subjects with DM. Data extracted included the journal citation, publication year, country of origin, study design, and a summary of the pertinent findings.

RESULTS

Our search yielded nine clinical studies and 10 animal studies. The results of the clinical studies suggest that Li-ESWT is a safe and effective treatment in men with well-controlled DM and moderate or better ED. However, the benefit is less durable in diabetic men than nondiabetic men. The results of the animal studies suggest that Li-ESWT can significantly improve erectile function in diabetic rat models with ED.

CONCLUSIONS

The examined studies present encouraging results for the use of Li-ESWT to treat diabetic men with ED. Future studies, particularly robust randomized controlled trials, are necessary to confirm these findings and provide long-term follow-up.

Placebo-Controlled Study of Effects of Low-Energy Shockwave Therapy (LE-ESWT) on Erectile Tissue in a Diabetic Animal Model

Objective

Low-energy extracorporeal shockwave therapy (LE-ESWT) has been shown to induce organ repair and neo-vascularization. The ability of LE-ESWT to improve erectile function in rodents as measured by improvements in intracavernosal pressure is well-established in various pathological situations. The underlying molecular mechanism are unclear and likely vary between different disorders, making rational drug design for synergetic effects with LE-ESWT difficult, without further research. In this placebo-controlled study, we aim to establish whether LE-ESWT can activate neovascularization biomarkers in diabetic tissues.

Material and Methods

Forty Wistar rats, aged 8 weeks, were randomly divided into 4 groups: 8 untreated controls, 12 controls that underwent LE-ESWT treatment, 8 controls with induced diabetes mellitus (DM) and 12 with DM underwent LE-ESWT treatment. DM was induced by streptozotocin. LE-ESWT treatment was performed with a Duolith SD1 machine (Storz), with a total amount of energy of 6.4 J per treatment. The rats received a total of three LE-ESWT treatments with 2-week intervals between treatments.

Results

Diabetic rats had significantly elevated blood glucose concentrations compared to control rats (P < 0.001) and experienced significant weight loss compared to controls (P < 0.001). Diabetic rats had elevated creatinine and urea and lower albumin (P < 0.001). Histologic analysis of penile tissue showed significant levels of vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) expression in the LE-ESWT groups compared to controls (P< 0.01).

Conclusion

LE-ESWT induces neo-angiogenesis as expressed by VEGF and FGF in erectile tissue in normal and diabetic rats.

The Alteration of HDL in Patients with AMI Inhibited Angiogenesis by Blocking ERK1/2 Activation

Objective. High-density lipoprotein (HDL) was found vasoprotective, but numbers of patients with acute myocardial infarction (AMI) have normal or even high levels of pathological HDL (pHDL). So, we investigate the mechanism of pHDL in AMI patients on angiogenesis. Methods. HDL with normal levels from healthy subjects (nHDL, control group, $n=20$ ) and patients with AMI (pHDL, experimental groups, $n=30$ ) were obtained by super high speed centrifugation. Then, effects of HDL on proliferation, migration, angiogenesis, and expression of ERK1/2 and its phosphorylation in human umbilical vein endothelial cells (HUVEC) with or without PD98059 (inhibitor of ERK1/2) preincubation were detected. Results. Compared with the control group (nHDL), HDL from the experimental group (pHDL) significantly inhibited the phosphorylation of ERK1/2, proliferation, migration, and angiogenesis of HUVEC ( $P<0.05$ ), while these effects of HDL could substantially be blocked by preincubation of PD98059 ( $P<0.05$ ). Conclusion. HDL in AMI patients affects angiogenesis by inhibiting ERK1/2 activation free from HDL levels.

The Basic Science Behind Low-Intensity Extracorporeal Shockwave Therapy for Erectile Dysfunction: A Systematic Scoping Review of Pre-Clinical Studies

INTRODUCTION

Despite recent promising clinical results, the underlying mechanism of action of low-intensity extracorporeal shockwave therapy (Li-ESWT) for erectile dysfunction (ED) is mostly unclear and currently under investigation.

AIM

To systematically identify and evaluate evidence regarding the basic science behind Li-ESWT for ED, discuss and propose a putative mechanism of action, address the limitations, and imply insights for further investigation in the field.

METHODS

Using Cochrane's methodologic recommendations on scoping studies and systematic reviews, we conducted a systematic scoping review of the literature on experimental research regarding Li-ESWT for ED and other pathologic conditions. The initial systematic search was carried between January and November 2017, with 2 additional searches in April and August 2018. All studies that applied shockwave treatment at an energy flux density >0.25 mJ/mm² were excluded from the final analysis.

MAIN OUTCOME MEASURE

We primarily aimed to clarify the biological responses in erectile tissue after Li-ESWT that could lead to improvement in erectile function.

RESULTS

59 publications were selected for inclusion in this study. 15 experimental research articles were identified on Li-ESWT for ED and 44 on Li-ESWT for other pathologic conditions. Li-ESWT for ED seems to improve erectile function possibly through stimulation of mechanosensors, inducing the activation of neoangiogenesis processes, recruitment and activation of progenitor cells, improving microcirculation, nerve regeneration, remodeling of erectile tissue, and reducing inflammatory and cellular stress responses.

CLINICAL IMPLICATIONS

Improving our understanding of the mechanism of action of Li-ESWT for ED can help us improve our study designs, as well as suggest new avenues of investigation.

STRENGTHS & LIMITATIONS

A common limitation in all these studies is the heterogeneity of the shockwave treatment application and protocol.

CONCLUSION

Li-ESWT for ED, based on current experimental studies, seems to improve erectile function by inducing angiogenesis and reversing pathologic processes in erectile tissue. These studies provide preliminary insights, but no definitive answers, and many questions remain unanswered regarding the mechanism of action, as well as the ideal treatment protocol. Sokolakis I, Dimitriadis F, Teo P, et al. The Basic Science Behind Low-Intensity Extracorporeal Shockwave Therapy for Erectile Dysfunction: A Systematic Scoping Review of Pre-Clinical Studies. J Sex Med 2019;16:168-194.