Biochemical assay of collagen and elastin in the normal and varicose vein wall

Alterations of the connective tissue in the varicose vein wall have been noted by several investigators; however, the cause of the vein dilatation has still not been established. The aim of this study was to find a biochemical explanation to the development of varices by evaluating sensitive biochemical markers of collagen and elastin in the varicose vein wall. 4-L-Hydroxyproline (HYP), as a marker of collagen content, and desmosine (DES) and isodesmosine (IDES), as markers of elastin, were measured in 47 macroscopically dilated and 32 nondilated segments of 20 varicose saphenous veins collected from 20 patients with varices. The same measurements were made in 24 fragments of normal saphenous veins collected from 14 patients in whom the vein was removed to be used for graft procedures. HYP (collagen) and DES and IDES (elastin) were determined with a colorimetric method and HPLC, respectively. ANOVA test was used to compare mean values (+/- SD). HYP and collagen content were similar in varicose and normal veins. There was a significant reduction of both DES and IDES in dilated segments of varicose veins (P < 0.05 vs normal veins and nondilated segments); the ratio of elastin to collagen was lower in varicose than normal veins (P < 0.05), and this reduction was most significant in the dilated segments (P < 0.01 vs normal veins). These results suggest that dilatation of the varicose vein wall may be related to some defect of elastin metabolism. Further studies on the metabolic activity of vein muscle cells are required.