Distribuição de proteoglicanos e outros componentes da matriz extracelular em artérias normais de adultos jovens

Abstract

Although cardiovascular diseases are the main cause death globally, factors affecting the differential location of atherosclerotic lesions are still not well understood. Of the arterial extracellular matrix components, proteoglycans are thought to be involved in atherogenesis by binding plasma lipoproteins. We thus investigated whether the distribution of proteoglycans and other proteins in normal human arteries correlates with the susceptibility of a given artery to atherosclerosis. Arterial samples from the left coronary, abdominal aorta, common iliac, right renal, and pulmonary trunk were obtained during autopsy of 15 males aged 17-28 years who had died of accidents. Morphometry of arterial layers was done on tissue sections stained with hematoxylin-eosin, Masson's trichrome, and Weigert's resorcinfuchsin, while immunohistochemistry was carried out using primary antibodies against the proteoglycans decorin, lumican, biglycan, and versican (v1), as well as against fibronectin and smooth muscle alpha-actin. Total collagen concentration in the arterial wall was determined by a biochemical method, and the intensity of immunostaining was assessed by a color deconvolution technique. Data were analyzed by one-way ANOVA followed by the Holm-Sidak multiple comparisons test. Protein expression of proteoglycans did not differ among the arteries, but varied significantly between layers. In all arteries, decorin was expressed mostly in the adventitia. The intima/media ratio was much higher in atherosclerosis-prone arteries (coronary, aorta) as compared to atherosclerosis-resistant vessels (renal, pulmonary trunk). Collagen content was similar in all arteries. Arteries at a higher risk for atherosclerosis consistently have thicker intimas, whereas their proteoglycan contents do not differ from those of vessels at a lower risk.