Oxidative Stress and Inflammation in Renal Patients and Healthy Subjects

The first goal of this study was to measure the oxidative stress (OS) and relate it to lipoprotein variables in 35 renal patients before dialysis (CKD), 37 on hemodialysis (HD) and 63 healthy subjects. The method for OS was based on the ratio of cholesteryl esters (CE) containing C18/C16 fatty acids (R2) measured by gas chromatography (GC) which is a simple, direct, rapid and reliable procedure. The second goal was to investigate and identify a triacylglycerol peak on GC, referred to as TG48 (48 represents the sum of the three fatty acids carbon chain lengths) which was markedly increased in renal patients compared to healthy controls. We measured TG48 in patients and controls. Mass spectrometry (MS) and MS twice in tandem were used to analyze the fatty acid composition of TG48. MS showed that TG48 was abundant in saturated fatty acids (SFAs) that were known for their pro-inflammatory property. TG48 was significantly and inversely correlated with OS. Renal patients were characterized by higher OS and inflammation than healthy subjects. Inflammation correlated strongly with TG, VLDL-cholesterol, apolipoprotein (apo) C-III and apoC-III bound to apoB-containing lipoproteins, but not with either total cholesterol or LDL-cholesterol

Triacylglycerol Fatty Acid Composition in Diet-Induced Weight Loss in Subjects with Abnormal Glucose Metabolism – the GENOBIN Study

BACKGROUND: The effect of weight loss on different plasma lipid subclasses at the molecular level is unknown. The aim of this study was to examine whether a diet-induced weight reduction result in changes in the extended plasma lipid profiles (lipidome) in subjects with features of metabolic syndrome in a 33-week intervention. METHODOLOGY/PRINCIPAL FINDINGS: Plasma samples of 9 subjects in the weight reduction group and 10 subjects in the control group were analyzed using mass spectrometry based lipidomic and fatty acid analyses. Body weight decreased in the weight reduction group by 7.8+/-2.9% (p<0.01). Most of the serum triacylglycerols and phosphatidylcholines were reduced. The decrease in triacylglycerols affected predominantly the saturated short chain fatty acids. This decrease of saturated short chain fatty acid containing triacylglycerols correlated with the increase of insulin sensitivity. However, levels of several longer chain fatty acids, including arachidonic and docosahexanoic acid, were not affected by weight loss. Levels of other lipids known to be associated with obesity such as sphingolipids and lysophosphatidylcholines were not altered by weight reduction. CONCLUSIONS/SIGNIFICANCE: Diet-induced weight loss caused significant changes in global lipid profiles in subjects with abnormal glucose metabolism. The observed changes may affect insulin sensitivity and glucose metabolism in these subjects. TRIAL REGISTRATION: ClinicalTrials.gov NCT00621205

Analysis of changes in triacylglycerol ratios in mouse liver and plasma in response to a liver X receptor agonist

An LC-MS method was developed for the analysis of triacylglycerols (TAG) in mouse liver extracts and plasma samples. C57 Mice were treated with two LXR agonists that have been shown to upregulate TAGs, T0901317 (T1317) or Org 264693 and compared to vehicle dosed animals. The dose used was 30 mg kg(-1), once daily, with three different dose regimes; 24 H, 48 H and 5 day. The TAG ratios measured were C52: 2/C54: 3 and C52: 3/C54: 4, which corresponded to a decrease in the palmitate and an increase in oleate composition of the TAGs. A significant change in the C52: 2/C54: 3 ratio was observed with all dose regimes and a good correlation was obtained between liver and plasma samples. In a separate study, the same compounds were dosed to LXR alpha and LXR beta knock-out (KO) mice at 30 mg kg(-1), once daily, for 5 days. The LXR beta KO mice showed similar TAG ratio changes to the C57 mice, whereas the LXR alpha KO mice showed no change in TAG ratios versus vehicle dosed animals. Measurements of lipid liability in response to an LXR agonist are typically made by measuring total liver TAG levels, which here, only showed a significant effect after the 48 H and 5 day dose regimes. By using a ratio measurement analysis could be performed on plasma samples, greatly simplifying the sample preparation procedure, without the requirement for either calibration curves or an internal standard