Declining density of intimal smooth muscle cells as a precondition for atheronecrosis in the coronary artery.

As arteries move from a healthy youth toward the atheronecrotic state of later life, they maintain a record which can be read by measuring the declining densities of intimal smooth muscle cells. Atheronecrosis is found when the artery is marked by expanded collagenous matrix, which dilutes the resident smooth muscle cells to a critically low cell density. Aging produces atheronecrosis through effects that are associated with diminishing cell density, without need to consider any other mechanism. Male-female differences in atheronecrosis could, in a statistical sense, be fully explained by a faster decline of cell density in men. Arteries with low cell densities foster inception of atherosclerotic "plaques" when they are focally infiltrated by collections of foam cells. These findings emerge from morphometric assessment of hematoxylin and eosin stained paraffin sections of coronary arteries obtained at autopsy in a series of forensic cases.