Apolipoprotein E genotype and changes in serum lipids and maximal oxygen uptake with exercise training

Area of Science:

• Exercise physiology
• Genetics
• Metabolic disorders

Background:

• Physical activity is known to improve lipid profiles by influencing triglyceride (TG) metabolism.
• Apolipoprotein E (Apo E) plays a key role in clearing TG by mediating lipoprotein binding to hepatic receptors.
• The specific roles of Apo E in skeletal muscle and nervous tissue are less understood.

Purpose of the Study:

• To investigate whether variations in Apo E genotype impact the lipid and physiological responses to a structured exercise training program.
• To analyze differences in response (Delta) to training among common Apo E genotypes (E2/3, E3/3, E3/4).

Main Methods:

• Recruited 120 subjects into 6 gender-specific cohorts, stratified by common Apo E genotypes (E2/3, E3/3, E3/4).
• Measured anthropometrics, maximal oxygen uptake (Vo2max), serum lipids, and post-heparin plasma lipase activities before and after 6 months of supervised exercise.
• Analyzed differences in response (Delta) to training among the Apo E genotypes as the primary outcome.

Main Results:

• Pre-training lipid differences among genotypes aligned with population studies (higher TGs in E2/3, lower LDL-C in E2/3).
• Exercise training decreased TGs (11% overall) and improved Total Cholesterol/HDL and LDL/HDL ratios in E2/3 and E3/3 groups, but worsened them in E3/4.
• Aerobic capacity (Vo2max) increased significantly across all genotypes, with greater improvements observed in E2/3 and E3/4 groups compared to E3/3 (P <.01 for Delta).

Conclusions:

• This is the first prospective study showing that Apo E genotype influences serum lipid response to exercise training, consistent with known metabolic variations.
• Surprisingly, Apo E genotype also affects the magnitude of aerobic capacity increase from exercise, potentially due to uncharacterized effects on nerve and skeletal muscle function.