Alterations of the extracellular matrix of venous walls in varicous veins

Background: Investigation of changes in normal veins which result in the fo rmation of varicosis led to examination of the histological organisation of the vessel wall and to histomorphological alterations in the region of the extracellular matrix. Patients and methods: The expression pattern of the matrix proteins collage n IV, fibronectin, laminin, tenascin, and undulin as well as the structure and orientation of elastic fibres were determined by means of immunohistoch emical staining. Results: All varices exhibited an increased expression pattern in compariso n to healthy veins. The venous vessel wall was often non-homogeneously enla rged. The intima was always more involved than the media and showed enhance d accumulation, whereas, the adventitia was not influenced by the pathologi cal process. Collagen IV exhibited an early accumulation, especially in the subendothelial region. The other matrix proteins demonstrated an increase in fibre propagation parallel to the enlargement of the vessel wall. Essent ially: an augmented de novo synthesis of fibres with an irregular arrangeme nt and the formation of local plaques was found Elastic fibres were enhance d by slight involvement of the vessel wall and were reduced and fragmented during increased involvement of the venous wall which explained the rigidit y of varices in contrast to normal veins.