Increased expression of a 68-kDa protein in the corpus cavernosum of some men with erectile dysfunction

Erectile dysfunction (ED) may be caused by abnormalities of intracavernous penile structures. In order to investigate whether specific proteins could be identified that might be related to ED, the composition of structural proteins in cavernous tissues of patients with ED was compared to that of normal cavernous tissues by gel electrophoresis. Increased expression of a 68-kDa nonionic detergent extraction-resistant protein was demonstrated in tissues of more than half of the patients with vasculogenic ED, whereas only one out of nine normal cavernous tissues showed the same phenomenon. Increased expression was not related to a specific type of vascular insufficiency, aging, or diabetic constituency. Histochemical and immunochemical studies revealed that the increased amount of the 68-kDa protein is not merely the result of a surplus of nervous, smooth muscle, or elastic tissues. Furthermore, antibodies specific for 68-kDa neurofilament and 62- to 67.5-kDa tropoelastin did not recognize the 68-kDa protein on Western blots. The possibility that the 68-kDa protein may help us understand the etiology of certain cases of erectile dysfunction is discussed.