Protective role of interleukin-10 in atherosclerosis

The potential role of anti-inflammatory cytokines in the modulation of the atherosclerotic process remains unknown. Interleukin (IL)-10 has potent dea ctivating properties in macrophages and T cells and modulates many cellular processes that may interfere with the development and stability of the ath erosclerotic plaque. IL-10 is expressed in human atherosclerosis and is ass ociated with decreased signs of inflammation. In the present study, we show that IL-10-deficient C57BL/6J mice fed an atherogenic diet and raised unde r specific pathogen-free conditions exhibit a significant 3-fold increase i n lipid accumulation compared with wild-type mice. Interestingly, the susce ptibility of IL-10-deficient mice to atherosclerosis was exceedingly high ( 30-fold increase) when the mice were housed under conventional conditions. Atherosclerotic lesions of IL-10-deficient mice showed increased T-cell inf iltration, abundant interferon-gamma expression, and decreased collagen con tent. In vivo, transfer of murine IL-10 achieved 60% reduction in lesion si ze. These results underscore the critical roles of IL-10 in both atheroscle rotic lesion formation and stability. Moreover, IL-10 appears to be crucial as a protective factor against the effect of environmental pathogens on at herosclerosis. The full text of this article is available at http://www.cir cresaha.org.