Spontaneous and diet-aggravated atherosclerosis in White Carneau pigeons genetically selected for discordant blood pressure.

White Carneau pigeons, prone to atherosclerosis, were selectively bred for either high (HBP) or low (LBP) blood pressure to study blood pressure-atherosclerosis interaction. Sixty-four HBP and 45 LBP pigeons, of both sexes and 16-30 months of age, were used to evaluate spontaneous atherosclerosis and the response to a moderately atherogenic diet. At 0 time, HBP pigeons had a greater percentage of aortic intima covered with fatty streaks and a lesser involvement with raised plaque. After 4 and 6 months of dietary treatment, the HBP pigeons with plasma cholesterol concentrations elevated only 22 and 8% above basal level responded with greater increases in the extent and severity of raised plaque whereas LBP pigeons changed little. On the average, medial thickness and medial areas of the atherosclerosis-free proximal aorta were greater in HBP compared to LBP at all times. Lower compliance of the aorta in the HBP line at 6 months (0.49 +/- 0.027 microliter/mm Hg/cm thoracic aorta) compared to LBP (0.57 +/- 0.036) suggested stiffer arterial walls in the HBP line. The findings suggest that HBP pigeons selected for increased blood pressure are more responsive to moderate hypercholesterolemia acting as a stimulus for atherosclerosis progression. The HBP pigeon line is therefore a useful animal model in which to investigate genetically derived hypertension-atherosclerosis interactions.