Role of mast cell chymase and tryptase in the progression of atherosclerosis: study in 44 autopsied cases.

The aim of this study was to describe the role of mast cell chymase and tryptase in the progression of atherosclerosis. Forty-four sections of aortas were obtained from autopsies. We assessed the macroscopic degree of atherosclerosis, microscopic intensity of lipid deposition in the tunica intima, percentage of collagen in the tunica intima, and density of immunostained mast cells. There was no significant difference between the density of mast cell tryptase and chymase concerning ethnicity, sex, cause of death, or degree of atherosclerosis. The density of mast cell chymase was significantly higher in the nonelderly group. The percentage of collagen was significantly higher in elderly patients. There was a positive and significant correlation between the degree of macroscopic atherosclerosis and lipidosis, the density of mast cell chymase and the percentage of collagen, the density of mast cell tryptase and the percentage of collagen, and lipidosis and the density of mast cell tryptase. The degree of macroscopic lesion of atherosclerosis increased proportionally with the increase in the density of mast cell chymase and tryptase and in the intensity of lipid deposition and with the percentage of collagen in the atherosclerotic plaques. Thus, mast cells may play a crucial role in aggravating atherosclerotic lesions.