Expression of elastic components in healthy and varicose veins

This study evaluates possible changes in the synthesis/degradation of elastic components of the vein wall in an attempt to explain the development of varicosis. Healthy and varicose saphenous veins were subjected to immunohistochemical analysis using anti-elastin, anti-fibrillin-1, anti-elastase, anti-transforming growth factor (TGF)-beta and anti-latent TGFbeta binding protein (LTBP)-2 monoclonal antibodies. In situ hybridization was performed using specific probes for tropoelastin and fibrillin-1. In healthy veins, elastin and fibrillin-1 showed even, overlapping distribution patterns indicating their particular abundance in the adventitia and at the intima/media interface. The expression of tropoelastin and fibrillin-1 was high in smooth muscle cells bordering the elastic laminae. Elastin, fibrillin-1, and cells expressing fibrillin-1 and tropoelastin mRNA showed a patchy disorganized pattern, particularly in the proximal varicose segments of patients under 50 years of age. Enhanced elastase activity was noted in both control and varicose specimens from elderly subjects. Varicose veins specimens showed greater LTBP-2 and TGF expression. Both molecules were detected in the subendothelium and the media, particularly in areas of marked injury. Our findings suggest that the development of the varicose condition involves a restructuring of the elastic component of the vein wall, perhaps as a consequence of changes in the transcription mechanisms of muscle layer cells.