High plasma levels of triglycerides (TG) are an independent risk factor in the development of cardiovascular disease, with about 50 % of the final levels being determined genetically. Apolipoprotein A5 ( APOA5 ) is the last discovered member of the apolipoprotein APOA1/C3/A4 gene cluster, found by comparative sequencing analysis. The importance of APOA5 gene for determination of plasma triglyceride levels has been suggested after development of transgenic and knock-out mice (transgenic mice displayed significantly reduced TG, whereas knock-out mice had high TG). In Czech population, alleles C-1131 and Trp19 are associated with elevated levels of plasma TG and higher risk of myocardial infarction development. These alleles also play some role in nutrigenetics and actigenetics of lifestyle interventions leading to the plasma cholesterol changes as well as in the pharmacogenetics of statin treatment. On the contrary, APOA5 mutations detected in Czech population did not show strict effect on plasma TG levels. Val153 → Met variant exhibit the sex-specific effect of HDL-cholesterol levels. The suggested roles of APOA5 variants in determination of the plasma remnant particles, plasma concentrations of C-reactive protein or some anthropometrical parameters were excluded., J. A. Hubáček ... [et al.]., and Obsahuje seznam literatury
Lipoprotein lipase (LPL) is a key factor determining the clearance of triglycerides from the circulation. The enzyme activity is tissue-specifically regulated by insulin, but it is not clear yet how insulin regulates the total LPL activity in the circulation. To answer such question, we measured LPL activity using the intravenous fat tolerance test (IVFTT) that was carried out 1 h before as well as 2 h and 4 h after oral administration of glucose (75 g) in eleven healthy male volunteers. In control experiments, no glucose was given to the subjects. Glucose administration resulted in an expected increase in plasma glucose and insulin and in a suppression of non-esterified fatty acid concentration. The LPL activity assessed in IVFTT as a k2 rate constant did not change in control experiments and decreased to 78 % and 73 % of baseline values 2 h and 4 h after glucose administration, respectively (p=0.01). Similarly, LPL activity measured in the plasma after intravenous injection of heparin at the end of the experiments was 16 % lower (p<0.05) after glucose administration. In conclusion, LPL activity is already downregulated in vivo 2 h after glucose administration. The results of our study indicate that repeated IVFTT is a promising approach for studying acute changes in LPL activity., E. Jindřichová, S. Kratochvílová, J. Kovář., and Obsahuje bibliografii a bibliografické odkazy