IS THICKENING OF THE BASAL LAMINA IN THE SAPHENOUS-VEIN A HALLMARK OFSMOKING

Objective-To investigate whether smoking causes ultrastructural change s in the intima of the proximal saphenous vein. Design-Proximal saphen ous veins from heavy smokers and non-smokers were examined with scanni ng and transmission electron microscopy to determine changes in surfac e ultrastructure, in the intercellular junction, and in the thickness of the basal lamina. Immunogold labelling was used to identify specifi c components of the endothelial basal lamina. Material-Vein specimens were obtained from patients undergoing varicose vein surgery (12 patie nts) or distal bypass surgery (eight patients). Main results-The only ultrastructural change that discriminated between specimens was thicke ning of the endothelial basal lamina. Ah specimens with a thickened ba sal lamina were from heavy smokers. Immunogold labelling studies showe d that the thickened basal lamina contained specific accumulations of fibronectin but not heparan sulphate proteoglycans, type IV collagen, or laminin. Conclusions-Two ultrastructural characteristics are associ ated with smoking: thickening of the endothelial basal lamina and a sp ecific accumulation of fibronectin in the thickened basal lamina. Such abnormalities in the saphenous veins from smokers may contribute to t he poorer performance of these veins as bypass conduits.