OBJECTIVE MEASUREMENT OF THE DIFFERENT COLLAGEN TYPES IN THE CORPUS CAVERNOSUM OF POTENT AND IMPOTENT MEN - AN IMMUNOHISTOCHEMICAL STAININGWITH COMPUTERIZED-IMAGE ANALYSIS

Quantitative measurements of the collagen types (I, III, and IV) in th e corpora cavernosa of potent and impotent men were carried out to inv estigate whether quantitative immunohistochemistry might contribute ad ditional information as to the cause of erectile dysfunction. The stud y group consisted of 22 men with various etiologies of impotence and 4 normal, potent men. The quantitative immunohistochemistry measurement s were performed by means of a cell-image processor. Three variables f or each of the three types of collagen were studied, namely, the mean optical density (MOD), which relates to histochemical staining intensi ty; the labeling index (LI), which is positively related to the percen tage of immunostaining; and the quick score (QS) index, which takes in to account both LI and MOD values. None of the quantitative parameters taken individually (monovariate statistical analyses) made it possibl e to obtain any statistically significant difference between the types of collagen of the group under study. The mean QS value recorded for collagen type IV was significantly lower than that noted for collagen type I in the psychogenic (P = 0.019), arteriogenic (P = 0.012), and v enogenic (P = 0.001) groups, whereas the MOD value was significantly l ower in the normal (P = 0.043), arteriogenic (P = 0.013), and venogeni c (P = 0.001) groups but not in the psychogenic group. The mean MOD of collagen type III was intermediate between that of the other types. I n contrast, the mean LI value recorded for collagen type IV was signif icantly lower only in the venogenic (P = 0.032) and psychogenic (P = 0 .049) groups as compared with the other groups. No objective qualitati ve change in the collagen types was observed that could be correlated to the etiology of erectile dysfunction. The significant difference se en in the quantitative parameters with regard to collagen type IV and the observed increase in the type I/III collagen ratio might attest to the notion that the response of the erectile tissue to ischemia is si milar to that of other organs. The net effect of these changes is a re stricted capacity for corporal expansion and alteration of the venoocc lusive mechanism.