Immunohistochemical detection of fibronectin in early and advanced atherosclerosis.

Fibronectin is known to be involved in the pathogenesis of atherosclerosis. We therefore applied paraffin-section immunohistochemistry, which permits detailed morphological analysis of the tissue distribution of fibronectin, in order to evaluate the alterations of fibronectin in terms of quantity and localization during the progression of atherosclerosis in humans. In 48/60 (80%) cases (p < 0.005) with early atherosclerotic lesions we found intense fibronectin staining presenting a distribution in continuous fibrils in the subendothelium around the fibrous plaque. The total amount of fibronectin was elevated. In 51/60 (85%) cases (p < 0.001) presenting advanced or complicated atherosclerotic lesions, the characteristic distribution of fibronectin in continuous fibrils was interrupted, fibronectin strands were fragmented and in regions where the sclerotic process was complete, fibronectin seemed to be almost absent. These findings reveal that fibronectin during atherosclerosis plays a role similar to that reported during the wound healing process and demonstrate a close relationship between quantity and topographical distribution of fibronectin and evolution of atherosclerosis. Further studies are required to determine whether fibronectin could be used as a marker for evaluation of the severity of atherosclerotic lesions.