Arterial and metabolic changes during the critical period of spontaneous sterol accumulation in pigeon aorta

Age-related changes in arterial structure and sterol chemistry were investigated during spontaneous (noncholesterol fed) atherogenesis in the White Carneau pigeon and compared to the changes in atherosclerosis-resistant Show Racer breeds. The critical period of spontaneous sterol accumulation occurs at 9–12 months of age in the White Carneau pigeons. At this age there is an increase in cholesteryl esters (rich in oleic acid) in the aorta. The Show Racer pigeons, however, did not show significant changes with age. Structurally, aortas from both breeds showed intimal cushions at birth which become prominent with age, with an increase in extracellular lipid and basement membranelike structures and the presence of a few foam cells at 9–12 months of age. The Show Racers showed a slightly lesser amount of lipid material when compared to White Carneau pigeons. During the period of lipid accumulation the White Carneau pigeons showed a significantly decreased excretion of total fecal steroids P < 0.05) with major changes in the neutral sterol fraction ( P < 0.01) when compared to Show Racers. The study has identified the critical age of arterial sterol accumulation in the White Carneau pigeons during spontaneous atherosclerosis and has shown alteration in cholesterol balance at this age.