Kinin receptors in human vascular tissue: their role in atheromatous disease

Using samples of many human blood vessels, obtained at autopsy and specific antibodies directed to peptide sequences of the kinin B1 and B2 receptors, we demonstrate the localisation of these receptors within the human vascular system using standard immunolabelling techniques. In large elastic arteries and veins, kinin receptors are present only in the endothelial cells whereas in all muscular arteries and arterioles, these receptors are present in both the endothelial and smooth muscle cells. The identification of kinin receptors in human blood vessels confirms that kinins may modulate both vascular permeability and contractility. The incidental finding at histology, of patchy atheromatous disease in the coronary, femoral, vertebral and pericallosal arteries, assisted in elucidating the role of these receptors in the commonest disease affecting human blood vessels. Intense labelling for B1 receptors was observed in the endothelial cells, foamy macrophages, inflammatory cells and fibroblasts within the thickened intima of the plaque as well as in smooth muscle cells of the underlying tunica media. Immunoreactive B2 receptors were also observed in these cells but with reduced intensity. The intense immunolabelling of B1 receptors in these regions suggest that these may be induced by atheromatous disease and may have therapeutic importance for the B1 receptor antagonists.