High density lipoprotein deficiency syndrome in chickens is not associated with an increased susceptibility to atherosclerosis

A spontaneous high density lipoprotein (HDL) deficiency syndrome in chickens associated with a Z-linked (sex-linked) mutation has been reported (F. Poermama et al, J Lipid Res 1990;31:955-963). The mutant, called WHAM (Wisconsin hypo-alpha mutant), has a 70-90% reduction in plasma HDL cholesterol and apolipoprotein A-I (apo A-I) concentrations. In the present study, the effect of the HDL deficiency on diet-induced or spontaneous atherosclerosis was assessed. Control chickens maintained on a highcholesterol diet for 28 weeks experienced a 2.4-fold rise in the plasma very low density lipoprotein cholesterol concentration, while the same diet induced a 3.7-fold rise in the low density lipoprotein cholesterol concentration in WHAM chickens. The high-cholesterol diet did not elevate the plasma HDL cholesterol or apo A-I concentrations in either group. Both the aortic area of involvement and the width of lesions were quantified by gross and microscopic examination, respectively. Cholesterol feeding produced a significant increase in the area of the aorta with atherosclerotic lesions in both control and mutant chickens. The HDL deficiency in WHAM chickens did not correlate with a higher lesion area or increased lesion thickness. To assess the effect of HDL deficiency on spontaneous atherosclerosis, a separate group of control and WHAM chickens was maintained on a low-fat, cholesterol-free diet for 3 years. At the end of the 3-year period, the area and thickness of the spontaneous aortic lesions in control and WHAM chickens were not significantly different. Spontaneous HDL deficiency in chickens is therefore not associated with increased susceptibility to atherosclerosis.