Introduction: Cardiovascular disease, the leading cause of death in developed countries, is commonly due to atherosclerosis. Studies have demonstrated association between leukocyte telomere shortening (LTS), extent of atherosclerotic lesions and accelerated cell senescence. Further LTS is associated with dietary intake. However, efforts to link LTS, diet and extent of lesions have been unsuccessful in humans due to difficulties controlling diet in large human population studies. To begin addressing these critical issues, we controlled dietary fat (high-fat, HF) in baboons for 2yrs - a well-developed primate model of human atherosclerosis. This is the first study in primates showing correlation of LTS with both chronic HF diet and atherosclerotic lesions.
Hypothesis: We hypothesized that leukocyte telomere length decreased with chronic HF diet in baboons and is correlated with extent of atherosclerotic lesions.
Methods and Results: A cohort of pedigreed baboons (n=107; females=46, males=61) was fed a HF diet for 2yrs. Absolute leukocyte telomere lengths (LTL; kb/diploid genome) were quantified by qPCR before and after diet challenge. Total telomere length was calculated by computing the ratio of telomere quantity per single copy gene quantity (baboon LIPG). Mean LTL was significantly shorter after feeding baboons a HF diet for 2 yrs (paired t test, p=0.03). Baboons (n=232) maintained on a low fat diet for 2yrs showed no significant difference in LTL (p=0.47). These findings suggest that a HF diet accelerates LTS. Further we quantified the extent of atherosclerotic lesions in baboons after 2yr HF diet and found that LTL, adjusted for age and sex, were correlated with lesions in descending aorta (Pearson correlation, r=0.19; p=0.03). Interestingly this correlation was significant in females but not in males after adjusting for age (r=0.27, p=0.03).
Conclusions: LTS correlates with chronic feeding with a HF diet in baboons, is significantly correlated with arterial lesions and the correlation is sex-specific. These findings suggest that LTS may be a potential biomarker of extent of atherosclerosis.