Methyl-donor supplementation in obese mice prevents the progression of NAFLD, activates AMPK and decreases acyl-carnitine levels.

Non-alcoholic fatty liver disease (NAFLD) results from increased hepatic lipid accumulation and steatosis, and is closely linked to liver one-carbon (C1) metabolism. We assessed in C57BL6/N mice whether NAFLD induced by a high-fat (HF) diet over 8 weeks can be reversed by additional 4 weeks of a dietary methyl-donor supplementation (MDS). MDS in the obese mice failed to reverse NAFLD, but prevented the progression of hepatic steatosis associated with major changes in key hepatic C1-metabolites, e.g. S-adenosyl-methionine and S-adenosyl-homocysteine. Increased phosphorylation of AMPK-α together with enhanced ß-HAD activity suggested an increased flux through fatty acid oxidation pathways. This was supported by concomitantly decreased hepatic free fatty acid and acyl-carnitines levels. Although HF diet changed the hepatic phospholipid pattern, MDS did not. Our findings suggest that dietary methyl-donors activate AMPK, a key enzyme in fatty acid ß-oxidation control, that mediates increased fatty acid utilization and thereby prevents further hepatic lipid accumulation.

Effect of maternal obesity with and without gestational diabetes on offspring subcutaneous and preperitoneal adipose tissue development from birth up to year-1.

BACKGROUND: Maternal obesity and gestational diabetes mellitus (GDM) may independently influence offspring fat mass and metabolic disease susceptibility. In this pilot study, body composition and fat distribution in offspring from obese women with and without GDM and lean women were assessed within the 1st year of life, and maternal and newborn plasma factors were related to offspring adipose tissue distribution. METHODS: Serum and plasma samples from pregnant obese women with (n = 16) or without (n = 13) GDM and normoglycemic lean women (n = 15) at 3rd trimester and offspring cord plasma were used for analyzing lipid profiles, insulin and adipokine levels. At week-1 and 6, month-4 and year-1, offspring anthropometrics and skinfold thickness (SFT) were measured and abdominal subcutaneous (SCA) and preperitoneal adipose tissue (PPA) were determined by ultrasonography. RESULTS: Cord insulin was significantly increased in the GDM group, whereas levels of cord leptin, total and high molecular weight (HMW) adiponectin were similar between the groups. Neonates of the GDM group showed significantly higher SFT and fat mass until week-6 and significantly increased SCA at week-1 compared to the lean group that persisted as strong trend at week-6. Interestingly, PPA in neonates of the GDM group was significantly elevated at week-1 compared to both the lean and obese group. At month-4 and year-1, significant differences in adipose tissue growth between the groups were not observed. Multiple linear regression analyses revealed that cord insulin levels are independently related to neonatal PPA that showed significant relation to PPA development at year-1. Maternal fasted C-peptide and HMW adiponectin levels at 3rd trimester emerged to be determinants for PPA at week-1. CONCLUSION: Maternal pregravid obesity combined with GDM leads to newborn hyperinsulinemia and increased offspring fat mass until week-6, whereas pregravid obesity without GDM does not. This strongly suggests the pivotal role of GDM in the adverse offspring outcome. Maternal C-peptide and HMW adiponectin levels in pregnancy emerge to be predictive for elevated PPA in newborns and might be indicative for the obesity risk at later life. Altogether, the findings from our pilot study warrant evaluation in long-term studies. TRIAL REGISTRATION: German Clinical Trials Register DRKS00004370.

Role of the inducible nitric oxide synthase in the onset of fructose-induced steatosis in mice.

To test the hypothesis that the inducible nitric oxide synthase (iNOS) is involved in mediating the toll-like receptor 4-dependent effects on the liver in the onset of fructose-induced steatosis, wild-type and iNOS knockout (iNOS(-/-)) mice were either fed tap water or 30% fructose solution for 8 weeks. Chronic consumption of 30% fructose solution led to a significant increase in hepatic steatosis and inflammation as well as plasma alanine-aminotransferase levels in wild-type mice. This effect of fructose feeding was markedly attenuated in iNOS(-/-) mice. Hepatic lipidperoxidation, concentration of phospho-IκB, nuclear factor κB activity, and tumor necrosis factor-α mRNA level were significantly increased in fructose-fed wild-type mice, whereas in livers of fructose-fed iNOS(-/-) mice, lipidperoxidation, phospho-IκB, nuclear factor κB activity, and tumor necrosis factor-α expression were almost at the level of controls. However, portal endotoxin levels and hepatic myeloid differentiation factor 88 expression were significantly higher in both fructose-fed groups compared to controls. Taken together, these data suggest that (i) the formation of reactive oxygen species in liver is a key factor in the onset of fatty liver and (ii) iNOS is involved in mediating the endotoxin/toll-like receptor 4-dependent effects in the development of fructose-induced fatty liver.