Résumé : Alteration and reduction of intracavernous smooth muscle cells have been demonstrated in patients with vascular impotence. These modifications seem to correlate with intracavernous oxygen tension while the cavernous arteries are normal. Lectines are glycoproteins which can be used as histological markers to monitor functional and morphological changes of endothelium cells. In order to understand the ischemie factor in patients with veno-occlusive dysfunction, we have studied the endothelium of the helicine with two different types of lectines and quantify the staining with computerized image analysis. Eleven patients with corporeal venous insufficiency aged between 27 to 62 years-old (flow to maintain erection > 15 ml/min and arterial cavernous flow velocity > 35 cm/sec) were included in this study. Four patients aged between 44 and 58 years-old with normal erections represented control group. Immunohistochemical staining using two lectines (Wheat germ agglutinin (WGA) and the Ulex europaeus agglutinin (UEA I) was performed and analyzed with computerized image analysis. The labelling index for WGA and UEA I (representing the distribution of the endothelial cells of the small arteries) was similar for the two groups of patients. The mean optical density (MOD) value (representing the functional aspect of endothelial cells) was significantly different between the two groups (p<0.001). MOD, WGA and UEA I values are 3 times higher in patients with normal erections. Alterations in the function of the endothelial cells of the helicine arteries, detected by specific immunohistochemical staining using WGA and VEA I, could represent the first step in corporeal venous insufficiency.