Emerging gene and stem cell therapies for the treatment of erectile dysfunction

Abstract

Erectile dysfunction is a prevalent condition in all parts of the world and leads to significant morbidity and distress, not just for men but for their partners. Unfortunately, very few currently available treatments ameliorate underlying causes of the disorder and “cure” the disease state. Much recent effort has been focused on the development of gene and cell based approaches to rectify the molecular and tissue defects responsible for ED in human men. Gene therapy has been investigated in animal models for well over a decade as a modality by which to restore normal function to the penis; as of this time, however, only one human trial has been published in the peer reviewed literature. Stem cell therapy has been a topic of interest in more recent years although there are currently very few published reports in animal models and none in human men. In this review, we will briefly review the current literature on gene and stem cell based therapies and briefly speculate on direction for future research.

Mechanisms of Penile Erection and Basis for Pharmacological Treatment of Erectile Dysfunction

“…In many ways, the penis is a good target tissue for gene therapy because of its physical location, low blood flow in the nonerect state, and the internal structure of the CC. Gene therapy for treatment of ED has been reviewed extensively and proposed as one of potential new therapies for ED associated with, e.g., aging, diabetes, and cavernosal nerve injury Burnett et al, 2010;Harraz et al, 2010;Melman and Davies, 2010;Yoshimura et al, 2010). Almost all studies have been made in animals, and so far, only one has been performed in humans.…”

A guanidinylated bioreducible polymer as a novel gene carrier to the corpus cavernosum of mice with high‐cholesterol diet‐induced erectile dysfunction

“…Gene therapy for ED has been tried in various pathologic conditions (Harraz et al, 2010). However, no therapeutic genes have so far been approved for the treatment of patients with ED, even though the results at the pre-clinical level were promising.…”

“…One important reason for this lack of approval is the infidelity of the current gene delivery methods for the treatment of ED. Viral or naked plasmid vectors have been used the most in pre-clinical trials of gene therapy for ED (Harraz et al, 2010). Although viral vectors have a high transfection efficiency, they have potential risks of immunogenicity or mutagenesis.…”

Gene therapy as future treatment of erectile dysfunction

“…In addition, K + channel genes, which functionally enhance relaxation of cavernous smooth muscle, have also been tested as another category of genes for ED gene therapy. The current status of gene therapies for ED has been summarized in a recent thorough review by Harraz et al 17. Thus, in this article, we will review and update the information on gene therapies for the management of ED, especially focusing on three major categories of gene therapies, respectively, targeting the NO system, growth factors and K + ion channel mechanisms, including our recent studies using HSV vector-based neurotrophic factor gene therapies in rat models of ED (Fig.…”