Hereditary and dietary effects on apolipoprotein[a] isoforms and Lp[a] in baboons

Baboons possess Lpa] that is similar to human Lpa], including the presence of the unique protein, apoa]. Baboon apoa] occurred in at least nine isoforms distinguishable by size. Isoforms were resolved by 3-12% polyacrylamide gradient gel electrophoretic separation of serum proteins, and were detected with baboon apoa]-specific antibodies. Thirty one different apoa] isoform phenotypes were detected in a population of 165 unrelated baboons. Identical isoform phenotypes were observed in different samples from individual baboons, and isoform phenotypes were unaffected by changes in diet. In one experiment, 16 baboons were fed a series of five diets differing in amounts of cholesterol and saturated or unsaturated fats. There was no significant effect of diet on serum Lpa] levels. In another group of baboons (n = 70) controlled for age and dietary history, enrichment of the diet with cholesterol and saturated fat caused a small, but significant (P less than 0.005), increase (means = 0.6 mg/dl) in serum Lpa] concentration. Analysis of two large sire families suggested that apoa] isoform patterns and serum Lpa] concentrations were inherited. Putative parental alleles responsible for specific isoform bands appeared to segregate randomly. Heritability (h2) of serum Lpa] concentration was estimated to be 0.95 +/- 0.04. We conclude that apoa] isoform phenotypes and serum Lpa] concentrations are inherited, and that Lpa] concentrations are only slightly influenced by diet.