Interleukin-1 beta (IL-1 beta) is known to have a number of effects on the different cell types present within coronary arteries. In this study we identified the location and phenotype of cells containing IL-1 beta in human coronary artery specimens from patients suffering from either coronary atherosclerosis or cardiomyopathy and correlated the presence of IL-1 beta with disease severity. Luminal endothelial cells, adventitial vessel wall cells, and macrophages were double labeled immunohistochemically for IL-1 beta protein and a cell type-specific monoclonal antibody for either endothelial cells or macrophages. In situ hybridization was performed to locate the presence of IL-1 beta mRNA within the coronary artery wall. In this study IL-1 beta protein was found to be increased in the adventitial vessel walls of atherosclerotic coronary arteries compared with coronary arteries from nonischemic cardiomyopathic hearts. This increase was directly proportional to the severity of coronary atherosclerosis. IL-1 beta protein was also detected in luminal endothelium and macrophages of atherosclerotic coronary arteries and coronary arteries from nonischemic cardiomyopathic hearts. IL-1 beta mRNA was found in luminal endothelial cells, adventitial vessel endothelial cells, and macrophages. We conclude that IL-1 beta is produced by endothelial cells and macrophages in coronary arteries from ischemic hearts and to a lesser extent from nonischemic cardiomyopathic hearts.

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Arteriovenous bypass graft failure has a huge economic effect on health care resources, and a devastating effect o the patient. The attenuation of vein wall thickening, with subsequent luminal narrowing and occlusion, is a major goal in improving the longevity of the venous graft, to reduce secondary percutaneous and surgical interventions. The biodegradable external stent demonstrated in this study has possible clinical applications in bypass procedures with autogenous venous tissue, and represents a novel approach to ameliorating the problem of intimal hyperplasia that plagues these grafts.

A nonrestrictive, biodegradable (polyglactin), external sheath reduces medial and intimal thickening in experimental saphenous vein grafts, possibly through inflammatory cell-mediated angiogenesis. If subsequent long-term studies confirm preservation of this beneficial effect, once the sheath biodegrades, this approach may have an advantage over the permanent polyester stent when applied clinically.

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