RESUMO
Clear differences exist in the incidence and severity of atherosclerotic plaques that arise in different segments of the arterial tree. Aortic homograft transplant experiments in dogs showed that the greater incidence of plaque formation in the abdominal versus the thoracic aorta was due to intrinsic differences in the cell populations in these two segments rather than to hemodynamic factors. What is the basis for SMC diversity within a common vessel wall? Recent lineage analysis studies in the avian and mammalian embryo indicate that two distinct SMC lineages contribute to the formation of the major elastic outflow arteries including the aorta. A mixture of unique SMC types of diverse developmental lineages within a common vessel wall raises new questions about the potential for SMC type-specific responses to growth factors and cytokines involved in human atherosclerosis and restenosis