The effect of FABP2 promoter haplotype on response to a diet with medium-chain triacylglycerols

The fatty-acid-binding protein-2 (FABP2) gene has been proposed as a candidate gene for diabetes because the encoded protein is involved in fatty acid absorption and therefore may affect insulin sensitivity and glucose metabolism. The rare haplotype (B) of its promoter was shown to be associated with a lower risk for type 2 diabetes. The aim of this study was to investigate whether a polymorphism in the FABP2 promoter does affect the metabolic response to either an medium-chain triacylglycerol (MCT) or an long-chain triacylglycerol (LCT) diet, which were suggested to differ in transport mechanisms, in affinity to FABP2, in activating transcription factors binding to the FABP2 promoter and in their effects on insulin sensitivity. We studied 82 healthy male subjects varying in the FABP2 promoter (42 homozygous for common haplotype (A), 40 homozygous for the rare haplotype (B)) in an interventional study with either an MCT or LCT diet over 2 weeks to examine gene–nutrient interaction. The saturation grade of MCT was adjusted to that of the LCT fat. We determined glucose, insulin, triacylglycerols (TGs), chylomicron triacylglycerols and cholesterol before and after a standardised mixed meal before and after the intervention. HDL cholesterol increased in all groups, which was most pronounced in subjects homozygous for the common promoter haplotype A who received MCT diet (P = 0.001), but not significant in homozygous rare haplotype B subjects who received MCT fat. Subjects homozygous for FABP2 haplotype A showed a significant decrease in fasting and postprandial glucose (P = 0.01, 0.04, respectively) and a decrease in insulin resistance (HOMA-IR, P = 0.04) during LCT diet. After correction for multiple testing, those effects did not remain significant. Fasting and postprandial triacylglycerols, LDL cholesterol, chylomicron TGs and cholesterol were not affected by genotype or diet. MCT diet increased HDL cholesterol dependent on the FABP2 promoter haplotype. The effects of the promoter haplotype B could be mediated by PPARγ, which is upregulated by medium-chain fatty acids

Mechanical Regulation of Cardiac Aging in Model Systems

Unlike diet and exercise, which individuals can modulate according to their lifestyle, aging is unavoidable. With normal or “healthy” aging, the heart undergoes extensive vascular, cellular, and interstitial molecular changes that result in stiffer less compliant hearts that experience a general decline in organ function. While these molecular changes deemed “cardiac remodeling” were once thought to be concomitant with advanced cardiovascular disease, they can be found in patients without manifestation of clinical disease. It is now mostly acknowledged that these age-related mechanical changes confer vulnerability of the heart to cardiovascular stresses associated with disease such as hypertension and atherosclerosis. However, recent studies have aimed at differentiating the initial compensatory changes that occur within the heart with age to maintain contractile function from the maladaptive responses associated with disease. This work has identified new targets to improve cardiac function during aging. Spanning invertebrate to vertebrate models, we use this review to delineate some hallmarks of physiological vs. pathological remodeling that occur in the cardiomyocyte and its microenvironment, focusing especially on the mechanical changes that occur within the sarcomere, intercalated disc, costamere, and extracellular matrix (ECM)