Early Endothelial Dysfunction As A Marker Of Vasculogenic Erectile Dysfunction In Young Habitual Cannabis Users

Main Category: Urology / Nephrology
Also Included In: Alcohol / Addiction / Illegal Drugs
Article Date: 14 Jan 2009 - 7:00 PDT

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UroToday.com - This study analyzes vascular function and hormonal and metabolic parameters in young patients complaining erectile dysfunction (ED) and identifies the possible risk factors for ED in these patients.

Sixty-four patients (<40 years old) were included and penile and brachial flow measured by, respectively, ultrasound and plethysmography. The patients were divided into groups with organic and non-organic ED based on their penile blood flow capacity in response to pharmacological intracavernosal stimulation. Then a comparison was made of respective systemic endothelial function and metabolic and hormonal parameters between the groups.

Cannabis use was much more frequent in patients with organic ED and brachial blood flow in response to ischemic occlusion was also reduced in this patient group; also, increased insulin levels (despite the patients being lean!) were present without other hormonal parameters alterations. The authors identify the use of cannabinoids (by urine samples) as the main risk factor for having organic ED. The impact of cannabinoids on endothelial function is still controversial. In animal studies, there is a large body of evidence supporting a role for the endocannabinoid system (ECS) in improving endothelial function and nitric oxide production. Also, THC has been shown to improve endothelium-dependent relaxation. In addition, the endocannabinoid anandamide, improves neurogenic relaxation of the corpus cavernosum in diabetic rats. By contrast, occasional myocardial infarction after acute assumption of cannabis has been reported in humans. It is noteworthy that marijuana smoking by people with either silent or overt cardiovascular disease poses health risks because of the consequences of the resulting increased cardiac work, increased catecholamine levels, carboxyhemoglobin, and postural hypotension.

Hence, the authors hypothesize that in their young healthy subjects with no cardiovascular risk factors, prolonged cannabis use might have acted as a secretagogue on the endocrine pancreas through endocannabinoid receptor activation, thus inducing insulin resistance, endothelial dysfunction and different degrees of ED. The authors demonstrate for the first time that systemic endothelial function and pharmaco-stimulated penile arteries' inflow among patients with organic ED who are cannabis consumers vs. non-consumers are significantly different. This evidence suggests that chronic cannabis smoking may concur to the alteration of both endothelial-dependent and -independent vasodilatatory pathways. In such cases, the high sensitivity and accuracy of brachial flow-mediated vasodilation in detecting the presence of endothelial dysfunction may substitute dynamic penile duplex ultrasound performance since this latter is more invasive with respect to a younger subject. It is hypothesized that prolonged activation of ECS is able, somehow, to alter endothelial function and to determine an early damage of the erectile process. Further studies are necessary to determine the direct relationship between abuse of cannabis, plasma THC levels, onset of insulin resistance and the development of ED and damage reversibility once the cannabis use is withdrawn.

Written by Antonio Aversa, MD, PhD as part of Beyond the Abstract on UroToday.com

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