Resistant Maltodextrin Ameliorates Altered Hepatic Lipid Homeostasis via Activation of AMP-Activated Protein Kinase in a High-Fat Diet-Fed Rat Model

Many studies have shown that resistant maltodextrin (RMD) possesses blood cholesterol lowering and anti-obesity effects. In order to investigate the effect of RMD on lipid metabolism in the liver, rats were fed with a high-fat (HF) diet for 7 weeks to induce hyperlipidemia and fatty liver. Normal control rats were fed with a normal diet. HF-diet-fed rats were treated with 5% RMD for 8 weeks. The results showed that the increased plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities, the increased hepatic triglyceride and total cholesterol levels, and fatty liver in HF-diet-fed rats were significantly decreased after supplementation with RMD. Supplementation with RMD significantly (1) induced AMP-activated protein kinase (AMPK) phosphorylation; (2) inhibited the activities of acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), and HMG-CoA reductase (HMGCR); (3) suppressed the protein expression of peroxisome proliferator activated receptor (PPAR)-γ; (4) increased β-oxidation of fatty acids by increasing the protein expression carnitine palmitoyl transferase 1α (CPT-1α) in the livers of HF-diet-fed rats. Taken together, supplementation of RMD was capable of inhibiting lipogenic enzyme activities and inducing fatty acid β-oxidation through increasing AMPK activation, thereby reducing lipid accumulation in the liver.