Lipid transfer to high-density lipoprotein is greater in elderly individuals with higher predictive cardiorespiratory fitness for age

Abstract

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): FAPESP and CNPq Background Elderly individuals have higher coronary artery disease (CAD) risk. Triggering factors include diminished peak of oxygen consumption (VO2peak), commonly referred as cardiorespiratory fitness (CF), and increase in atherogenic lipid profile: non high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). The effect of aging on HDL-C is yet not clear, however, evaluating only the concentrations do not represent all HDL anti-atherosclerosis potential, aspects related to HDL metabolism and function can be more accurate to understand atherosclerosis process. Beyond that, elderly individuals also show reduced lipid transfer to HDL, an important assessment of HDL metabolism and function reported to be lower in CAD patients. Additionally, higher CF level is associated with longevity and lower hospitalizations rates and higher lipid transfer, independently of HDL-C. Data about different ages and absolute values of CF on lipids transfer are nonexistent. Purpose: To analyze the effect of paired CF absolute values and BMI in a healthy population of different ages on lipid transfer to HDL. Methods: 61 healthy individuals, enrolled in two groups: 30 young (27 ± 4 years, 21 females, BMI: 24.6 ± 2.6 kg/m², VO2peak: 33.9 ± 5.0 ml/kg/min) and 31 elderly (67 ± 5 years, 15 females, BMI: 23.9 ± 3.3 kg/m², VO2peak: 33.2 ± 4.5 ml/kg/min) that do not use any medication for chronic disease. Anthropometric data were collected. All participants performed treadmill cardiopulmonary test and the CF predictive value for age was calculated, according to each sex. Plasma lipids and cholesterol ester transfer protein (CETP) concentrations were determined. Lipid transfer was performed by incubating plasma with a donor lipoprotein-like nanoparticle containing radioactively labeled unesterified cholesterol (UC) and esterified cholesterol (EC), followed by chemical precipitation and radioactive count. Cholesterol transfers from the donor nanoparticle to HDL are expressed as %. For the statistical analysis Student"s t and Mann-Whitney tests were used according to data distribution. Results: Waist circumference (p = 0.0291) and waist-hip ratio (p < 0.0001) were higher in elderly. LDL-C (p = 0.0005) and non HDL-C (p = 0.0003) were higher in elderly, as well apolipoprotein A-I, B, and CETP concentration. HDL-C and triglycerides were equal between groups. EC (p = 0.0268) and UC (p = 0.0348) transfers to HDL were higher in elderly. VO2peak predictive by age expressed in percentage was higher in elderly (90 ± 13 vs. 120 ±18; p < 0.0001). Conclusion: Elderly individuals show higher anthropometric data and concentrations of atherogenic cholesterol lipoproteins; however, HDL-C was equal. When paired by absolute CF values and BMI with young adults, elderly subjects with high CF predicted by age, have higher cholesterol transfer to HDL which demonstrates greater HDL metabolism.