COMPARISON OF ANTIDESMIN AND ANTIACTIN STAINING FOR THE COMPUTERIZED ANALYSIS OF CAVERNOUS SMOOTH-MUSCLE DENSITY

Objective To compare the staining properties of antidesmin and anti-ac tin in cavernous biopsies and thus determine the optimal antibody for quantifying intracavernous smooth muscle content in the evaluation of erectile dysfunction. Patients and methods Twenty-two penile biopsies were taken from five normal potent patients, seven with venous leak an d 10 with arterial disease, with mean ages of 34.4, 48.8 and 54.8 year s, respectively. Biopsies were sectioned and successive sections stain ed immunohistochemically with antibodies for actin or desmin. Image an alysis was used to quantify the proportion of smooth muscle fibres in the cavernous tissue. Results There was a significant difference (P=0. 0001) between the mean percentage of cavernous smooth muscle fibres in normal potent men, stained with antidesmin (38.5%,SD 3.2) or anti-act in (45.2%, so 3.2) and that in the venous group (anti-desmin 27.4%, so 4.0%; anti-actin 34.2%, SD 5.3%) or the arteriogenic group (anti-desm in 23.7%, SD 4.4, anti-actin 28.9%, SD 4.9). There was no significant difference in the estimates with either staining method between the ve nogenic and arteriogenic patients. There was a direct relationship bet ween the cavernous smooth muscle density estimated by anti-desmin and antiactin staining (r = 0.96). Conclusion The anti-actin and anti-desm in staining methods gave equivalent results for discriminating between normal and impotent patients on the basis of the percentage of cavern ous muscle fibres. However, anti-actin staining tended to be more sens itive than anti-desmin.