Pathophysiology of diabetic sexual dysfunction.

Sexual dysfunction is common in patients with diabetes mellitus. Vascular, neurological and hormonal alterations are involved in this complication. Many studies showed altered endothelium-dependent and neurogenic relaxations in corpus cavernosum from diabetic patients with erectile dysfunction (ED). This finding has been associated with a lack of nitric oxyde (NO) production and a significant increase in NO synthase (NOS) binding sites in penile tissues, induced by diabetes. Advanced glycation endproducts (AGEs) concur to diabetic vascular complications by quenching NO activity and by increasing the expression of mediators of vascular damage such as vascular endothelial growth factor (VEGF), possessing permeabilizing and neoangiogenic effects, and endothelin-1 (ET-1), with vaso-constricting and mitogenic action. Moreover, the differential gene expression for various growth factors in penile tissues may be involved in the pathophysiology of ED associated with diabetes. Neuropathy is also likely to be an important cause of diabetic ED: morphological alterations of autonomic nerve fibers in cavernosal tissue of patients with diabetic ED have been demonstrated. Finally, androgens enhance nNOS gene expression in the penile corpus cavernosum of rats, suggesting that they play a role in maintaining NOS activity. However, sexual dysfunctions in women with diabetes has received less attention in clinical research. Several studies suggest an increased prevalence of deficient vaginal lubrication, making sexual intercourse unpleasant. Sexual dysfunction is associated with lower overall quality of marital relation and more depressive symptoms in diabetic women.