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.
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