B Lymphocytes and Macrophages in the Perivascular Adipose Tissue Are Associated With Coronary Atherosclerosis: An Autopsy Study

Abstract

Background Macrophages and T lymphocytes in the perivascular adipose tissue (Pv AT ) were previously linked to coronary artery disease. However, the role of these cells and B lymphocytes in the human Pv AT adjacent to unstable atherosclerotic plaques has not been investigated. Moreover, previous studies were inconclusive on whether Pv AT inflammation was restricted to the surroundings of the atheroma plaque. Methods and Results Coronary arteries were freshly dissected with the surrounding Pv AT . Atherosclerotic plaques were classified according to the internationally accepted anatomopathological criteria. Immune cells in the Pv AT were detected using immunohistochemistry and then quantified. We used linear and logistic regressions with robust standard errors, adjusted for possible confounding factors. In 246 atherosclerotic plaques (205 stable and 41 unstable plaques) from 82 participants (mean age=69.0±14.4 years; 50% men), the percentage of arterial obstruction was positively correlated with the densities of CD 68 + macrophages ( P =0.003) and CD 20 + B lymphocytes ( P =0.03) in the periplaque Pv AT . The number of cells was greater in the periplaque Pv AT than in the distal Pv AT (macrophages, P <0.001; B lymphocytes, P =0.04). In addition, the density of macrophages in the periplaque Pv AT was greater in the presence of unstable plaques ( P =0.03) and was also greater near unstable plaques than in the distal Pv AT ( P =0.001). CD 3 + T lymphocytes were not associated with percentage of obstruction and stable/unstable plaque composition. Conclusions The density of CD 20 + B lymphocytes and CD 68 + macrophages in periplaque Pv AT was increased with plaque size, and the CD 68 + macrophages were greater near unstable atherosclerotic plaques than near stable lesions. This inflammation was more intense in the periplaque Pv AT than in the Pv AT distal to the atherosclerotic plaques.