Rhesus monkey (Macaca mulatta) lipoprotein(a) and apolipoprotein(a): high frequency of small size apolipoprotein(a) isoforms

BackgroundLevels of lipoprotein(a), Lp(a), a genetically regulated independent cardiovascular risk factor present in humans and Old World monkeys, are impacted by the apolipoprotein(a), apo(a), gene. Allele-specific apo(a) levels, taking both the apo(a) genotypic and phenotypic characteristics into account, are useful markers to determine atherosclerotic cardiovascular risk. MethodsWe determined (i) the genetic variability of apo(a), (ii) Lp(a) levels, and (iii) allele-specific apo(a) levels in rhesus monkeys (n=95). ResultsLp(a) levels differed substantially between animals (range: 4-247nmol/l) with a skewed distribution toward lower levels. Lp(a) and allele-specific apo(a) levels were inversely related to the number of apo(a) Kringle 4 (K4) repeats. The median apo(a) size was 23K4 repeats, and the prevalence of a small size apo(a) (22K4) was 43%. ConclusionsDistribution of Lp(a) and allele-specific apo(a) levels in rhesus monkeys reflected the corresponding human patterns, but with a high prevalence of smaller apo(a) sizes.