Risk factors in pigeons genetically selected for increased atherosclerosis susceptibility

A strain of genetically selected White Carneau pigeons (WC-2) with increased atherosclerosis at similar plasma cholesterol concentrations as randomly bred (RBWC) pigeons was studied to evaluate the commonly known risk factors for atherosclerosis. Indicators for the presence of hypertension, diabetes mellitus, "stress", hyperuricemia and hypothyroidism were determined. In pigeons fed the atherogenic diet, major differences in atherosclerosis were seen between WC-2 and RBWC. WC-2 pigeons had more aortic surface covered with plaque and greater concentrations of aortic nonesterified cholesterol, esterified cholesterol, uronic acid, and hydroxyproline, as well as a greater prevalence and severity of coronary artery atherosclerosis. For WC-2 and RBWC pigeons we found similar levels of hypercholesterolemia, mean blood pressure, plasma triglyceride and glucose concentrations. In addition, several other physiological variables such as plasma uric acid, calcium and phosphorus concentrations, adrenal and thyroid weights which have been implicated in the pathogenesis of atherosclerosis were similar. The findings indicate that the differences in extent and severity of atherosclerosis between WC-2 and RBWC cannot be explained by differences in the risk factors studied. Possible genetic regulation of atherosclerosis by mechanisms operable in the arterial wall of WC-2 pigeons is suggested.