Adventitial macrophage and lymphocyte accumulation accompanying early stages of human coronary atherogenesis

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Atherosclerosis is considered a chronic inflammatory disease of the entire arterial wall, including the adventitia. Advanced coronary lesions with lipid cores are associated with adventitial inflammation, but the early inflammatory process in human coronary adventitia is largely unknown. We hypothesized that adventitial inflammatory cell infiltration accompanies the early stages of atherogenesis in human coronary arteries, and it is synchronous with the inflammatory process in the intima. Coronary artery samples were obtained from 111 forensic autopsy cases aged from 7 to 25 years. Adventitial and intimal macrophages, T lymphocytes and B lymphocytes, and intimal microvessels were detected by immunohistochemical methods and quantified by computerized image analysis. Body height, weight, waist circumference, and the size of mesenteric and omental fat depots were measured. Adventitial densities of macrophages and T lymphocytes were significantly higher in arteries showing intimal xanthomas than in cases with only scattered intimal macrophages. The xanthoma group also had significantly higher body mass index and larger visceral fat depots. Highest densities of all adventitial cell types were seen in intermediate lesions and fibroatheromas. There were significant positive correlations between intimal and adventitial densities of T cells and B cells in the groups with or without intimal xanthomas, but the positive correlation between intimal and adventitial macrophages was significant only in the group without xanthomas. Adventitial immune-inflammatory cell accumulation accompanies the early stages of coronary atherogenesis in young individuals, and lymphocyte accumulation seems to be synchronous in the intima and adventitia. Macrophage accumulation is also synchronous before xanthomas are seen.