Collagen subtype pattern in normal and varicose saphenous veins in humans.

Our present study was to determine the collagen subtype pattern in the greater saphenous vein of the lower limb, obtained from 21 normal (macroscopically and ultrastructurally non-varicose vein segments from non-varicose subjects) and 37 varicose subjects, and to compare affected (macroscopically and ultrastructurally varicose segments from varicose veins) vs. non-affected (macroscopically and ultrastructurally non-varicose segments from varicose veins) segments (16). After elastase pretreatment and partial pepsin digestion, types I, III & V collagens (CI, CIII, CV) were extracted selectively by differential salt precipitation and measured quantitatively in samples obtained from normal and varicose saphenous veins-either affected or unaffected segments. Significant elevations of water (p < 0.05) and collagen type I [CI] (p < 0.01) content in varicose veins (both affected and unaffected segments) as compared with normal saphenous veins were observed. The collagen type III (CIII) and collagen type V (CV) content of varicose veins were found to be slightly reduced as compared to normal veins and consequently the CI/(CIII+CV) ratio in varicose veins increased significantly (p < 0.02) as compared to normal veins. Elevation of the CI/(CIII+CV) ratio in varicose veins may cause considerable weakening of the venous wall, further supporting the "weak wall" theory of varicose vein etiology.