Clinical and animal experimental aspects of lipid metabolism disorders in erectile dysfunction

Abstract

Toxic and hypoxic-ischemic disturbances are currently under discussion as possible reasons for the pathogenesis of non-psychogenically caused erectile dysfunction. We were interested in the role of an impaired lipid metabolism in patients with erectile dysfunction.Lipid parameters and ultrastructural changes of the smooth muscles in the corpus cavernosum were investigated in patients with erectile dysfunction and, additionally, in hypercholesterolemic rabbits.105 patients with erectile dysfunctions who underwent a complete impotence work-up were divided into three groups: psychogenic, vascular (arteriocavernous and caverno-venous (non-responder in pharmacon testing)), and neurogenic erectile dysfunctions. The results from the lipoprotein analysis showed clear discriminations dependent on the pathogenesis of the erectile dysfunction. A marked increase of LDL and/or a decrease of HDL concentration was found in patients with vascular impotence (67%) as compared to those with psychogenic and neurogenic erectile failure. On further classification, 45% of the arteriogenic group and 84% of the patients with caverno-venous insufficiencies exhibited disorders in lipoprotein metabolism.Electronmicroscopic studies showed that hypercholesterolemia in rabbits could cause the same degenerative changes of the cavernous smooth muscle cells as could be found in men with vascularic impotence. The loss of cell contacts and of contractile myofilaments were also notable as was the appearence of nuclearpycnosis and the increase of connective tissue and collagen. An important finding was the loss of endothelial cells in the sinusoidal cavititis of the corpora cavernosa. The presence of these endothelial cells seems to be important for the relaxation ability of the smooth muscle cells. Application of an antagonist of the thromboxan receptor, Daltroban, showed a remarkable decrease of the ultrastructural changes and a significant reduction of cholesterol in the corporal tissue.The findings in animal experiments as well as the clinical results strongly support the hypothesis that disorders of lipid metabolism play a major role in the pathogenesis of vascular erectile dysfunction.