madman
Super Moderator
INTRODUCTION
The high prevalence of erectile dysfunction (ED) and the associated detriment to the quality of life for affected men and their partners underscore the need for effective therapy for this troubling condition.1 Contemporary algorithm for ED management relies on the on-demand use of self-administered medications or surgical placement of a prosthetic device to offset the disease process and allow for sexual activity.2 Although the introduction of effective oral and injectable agents for ED were revolutionary breakthroughs, no contemporary treatment options have been shown to restore the natural erectile physiology. Additionally, medications may be contraindicated, intolerable, unaffordable, or ineffective in many instances. Mechanical replacement of function, either through external or internal devices, has proven effective for many men, but remains generally less satisfactory than native function and carries associated risk.3
Given the large number of factors deemed contributory to development of ED, behavioral modifications (eg, weight loss, exercise, tobacco cessation) and optimization of conditions such as diabetes, hypertension, hypogonadism, and vascular disease are indicated.4 Even when patients are compliant and successful with such measures, improvements in erectile function tend to be modest and frequently insufficient to meet the needs of most patients.
The desire for restorative, rather than palliative, management strategies for ED has stimulated interest in gene- and cell-based therapies. Herein, we present a brief overview of the relevant physiology and pathophysiology for these targeted therapies, describe the existing data to support these novel therapeutics, and highlight areas for future research. Therapies such as low-intensity shock wave therapy and platelet-rich plasma (PRP) are also advertised as regenerative therapies for ED.5–7 Readers interested in energy-based therapies for ED are Raghav Pai and colleagues’ article, “Energy-based Therapies for Erectile Dysfunction: Current and Future Directions,” in this issue. We do not address PRP in detail in this report because, to our knowledge at the time of this writing, there is a paucity of published peer-reviewed data on this technology for the management of ED.
*INSIGHT FROM PHYSIOLOGY
*GENE THERAPY
*CONCERNS AND LIMITATIONS
FUTURE DIRECTIONS
The future direction of cellular therapies must be large-scale human studies. There are very few, if any, large, randomized, placebo-controlled studies in the field of novel therapeutics for ED. Thus, coordinated multicenter studies of adequate power are required. Efforts must establish safety and efficacy, as well as optimal dosing and delivery. Despite the number of animal studies suggesting benefits, more translation to human trials is essential. Comparisons between cellular and cell-free (eg, CM) therapies should continue as the latter may obviate some cost and ethical concerns if deemed satisfactory.
SUMMARY
Stem cell and gene therapy represent a promising area of study relative to developing truly restorative options for erectile function. The data from animal studies are impressive, but larger human trials are necessary. Given existing fears, it seems important that the future of valuable research isn’t jeopardized by opportunists. Both studies and clinical interventions should be conducted ethically, with appropriate patient counseling and fully informed consent.
The high prevalence of erectile dysfunction (ED) and the associated detriment to the quality of life for affected men and their partners underscore the need for effective therapy for this troubling condition.1 Contemporary algorithm for ED management relies on the on-demand use of self-administered medications or surgical placement of a prosthetic device to offset the disease process and allow for sexual activity.2 Although the introduction of effective oral and injectable agents for ED were revolutionary breakthroughs, no contemporary treatment options have been shown to restore the natural erectile physiology. Additionally, medications may be contraindicated, intolerable, unaffordable, or ineffective in many instances. Mechanical replacement of function, either through external or internal devices, has proven effective for many men, but remains generally less satisfactory than native function and carries associated risk.3
Given the large number of factors deemed contributory to development of ED, behavioral modifications (eg, weight loss, exercise, tobacco cessation) and optimization of conditions such as diabetes, hypertension, hypogonadism, and vascular disease are indicated.4 Even when patients are compliant and successful with such measures, improvements in erectile function tend to be modest and frequently insufficient to meet the needs of most patients.
The desire for restorative, rather than palliative, management strategies for ED has stimulated interest in gene- and cell-based therapies. Herein, we present a brief overview of the relevant physiology and pathophysiology for these targeted therapies, describe the existing data to support these novel therapeutics, and highlight areas for future research. Therapies such as low-intensity shock wave therapy and platelet-rich plasma (PRP) are also advertised as regenerative therapies for ED.5–7 Readers interested in energy-based therapies for ED are Raghav Pai and colleagues’ article, “Energy-based Therapies for Erectile Dysfunction: Current and Future Directions,” in this issue. We do not address PRP in detail in this report because, to our knowledge at the time of this writing, there is a paucity of published peer-reviewed data on this technology for the management of ED.
*INSIGHT FROM PHYSIOLOGY
*GENE THERAPY
*CONCERNS AND LIMITATIONS
FUTURE DIRECTIONS
The future direction of cellular therapies must be large-scale human studies. There are very few, if any, large, randomized, placebo-controlled studies in the field of novel therapeutics for ED. Thus, coordinated multicenter studies of adequate power are required. Efforts must establish safety and efficacy, as well as optimal dosing and delivery. Despite the number of animal studies suggesting benefits, more translation to human trials is essential. Comparisons between cellular and cell-free (eg, CM) therapies should continue as the latter may obviate some cost and ethical concerns if deemed satisfactory.
SUMMARY
Stem cell and gene therapy represent a promising area of study relative to developing truly restorative options for erectile function. The data from animal studies are impressive, but larger human trials are necessary. Given existing fears, it seems important that the future of valuable research isn’t jeopardized by opportunists. Both studies and clinical interventions should be conducted ethically, with appropriate patient counseling and fully informed consent.
