Alterations of the extracellular matrix of venous walls in varicous veins

Background: Investigation of changes in normal veins which result in the formation 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 collagen IV, fibronectin, laminin, tenascin, and undulin as well as the structure and orientation of elastic fibres were determined by means of immunohistochemical staining. Results: All varices exhibited an increased expression pattern in comparison to healthy veins. The venous vessel wall was often non-homogeneously enlarged. The intima was always more involved than the media and showed enhanced accumulation, whereas, the adventitia was not influenced by the pathological 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. Essentially: an augmented de novo synthesis of fibres with an irregular arrangement and the formation of local plaques was found Elastic fibres were enhanced by slight involvement of the vessel wall and were reduced and fragmented during increased involvement of the venous wall which explained the rigidity of varices in contrast to normal veins.