Endoplasmic reticulum stress in adipose tissue determines postprandial lipoprotein metabolism in metabolic syndrome patients

Scope: Our aim was to ascertain whether the quality and quantity of fat in the diet may influence the ER stress at the postprandial state in adipose tissue by analyzing the gene expression of chaperones, folding enzymes, and activators of the UPR. Methods and results: A randomized, controlled trial conducted within the LIPGENE study assigned 39 MetS patients to one of four diets: high-SFA (HSFA; 38% energy (E) from fat, 16% E as SFA), high MUFA (HMUFA; 38% E from fat, 20% E as MUFA), and two low-fat, high-complex carbohydrate (LFHCC; 28% E from fat) diets supplemented with 1.24 g/day of long-chain n-3 PUFA or placebo for 12 wk each. A fat challenge reflecting the same fatty acid composition as the original diets was conducted post intervention. sXBP-1 is induced in the postprandial state irrespective of the diet consumed (p < 0.001). BiP increases postprandially after consumption of diets HMUFA (p = 0.006), LFHCC (p = 0.028), and LFHCC n-3 (p = 0.028). Postprandial mRNA expression levels of CRL, CNX, PDIA3, and GSTP1 in AT did not differ between the different types of diets. Conclusion: Our results suggest that upregulation of the unfolded protein response at the postprandial state may represent an adaptive mechanism to counteract diet-induced stress. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.