Initial lesions of the elastic fibers and extracellular matrix in varicose veins: an inmunohistochemical and confocal microscopy study

Abstract

Chronic venous insufficiency (CVI) has high morbidity in middle and advanced age population. We studied varicose vein alterations in early stages to identify possible therapeutic targets. Saphenous veins from 10 patients were classified according to Color Doppler in proximal segment with lesions (Varicose vein, VV) and distal (normal vein, NV). We analyzed extracellular matrix (ECM), elastic fibers, collagen I and IV and SMC in sections stained with Masson trichrome, orcein, sirius red and collagen I and IV antibodies. Elastin was studied with confocal microscopy in intact veins (autofluorescence). Compared to NV, VV intima shows multifocal areas of endothelial denudation, deposition of powdery collagen and elastic material and short and thin elastic fibers. VV media has SMC atrophy, increased immature ECM deposition with few and small collagen I fibers and incomplete elastogenesis. Adventitia is thick with abundant mature collagen I and deposition and increased thick and irregularly distributed elastic fibers. Some areas of the distal NV segment also exhibited some of these abnormalities. We conclude that initial multifocal degeneration of adventitial elastic fibers, intimal elastogenesis and progressive atrophy of SMC are processes perpetuating CVI and irreversible lesions. Funding: Universidad Autónoma de Madrid (UAM/32).