Changes of elastic and collagen fibers in varicose veins

The resistance to stretch and the elasticity of the vein wall depend on the collagen and elastic fibers, respectively. Contradicting evidence exists, however, on the connective tissue concentration in varicose veins.

A prospective, comparative study was conducted at Asir Central Hospital and the College of Medicine in Abha, Saudi Arabia. Twenty-three vein specimens collected from both the proximal thigh long saphenous vein (LSV) and the distal calf blowouts in 10 primary varicose vein patients and from the normal, proximal thigh LSV in 3 young vascular trauma patients were examined. Paraffin sections stained with hematoxylin and eosin, Verhoeff von Gieson (VVG) and Masson's Trichrome stains were examined under the light microscope. Ultra thin sections were examined under the transmission electron microscope (TEM).

Compared with the normal control LSV, varicose vein sections showed increased diameter of the lumen and hypertrophy of the wall, mainly of the intima, due to increased amounts of collagen fibers. This marked fibrous infiltration disrupted the normal palisade arrangement of the intimal and the regular sheet-like arrangement of the medial smooth muscle cells. Collagen fibers also lost their normal pattern and showed abnormal forms. Elastic fibers lost their regular laminar arrangement and formed clumps or scattered fragments.

Varicose veins showed increased collagenosis and distortion of the elastic fibers. The presence of abnormal collagen to elastin ratio and the loss of the regular collagen/elastic lattice of the vein wall may play a major role in the pathogenesis of varicose veins.