85-OR]: Fetal triglyceride concentrations and apolipoprotein CIII glycosylation/sialylation in IUGR

Apolipoprotein CIII (apoCIII) is involved in triglyceride metabolism. More specifically, desialylation of apoCIII results in the inhibition of triglyceride catabolism. We therefore hypothesized that glycosylation/sialylation of apoCIII correlates with the elevated triglyceride concentrations observed in cord blood of IUGR fetuses.Venous cord blood samples of 36 IUGR and 49 preterm and term born controls (CTRL) were analyzed. Peak areas of the different apoCIII species (apoCIII0, apoCIII0', apoCIII1, apoCIII2) were determined by MALDI ToF mass spectrometry (MS). Peak areas of apoA1 or combined peak areas of apoCIII species (Σ apoCIII) were used as a reference. Ratios were correlated to triglyceride concentrations. Additionally, total apoCIII concentrations were measured using ELISA in a subset of 15 IUGR and CTRL samples.Spearman's Rank Correlation, non-linear regression analysis. Wilcoxon rank sum test.Total ApoCIII concentrations determined by ELISA did not differ between IUGR and CTRL. ApoCIII were correlated to triglyceride concentrations (IUGR ρ=0.60 p<0.032, CTRL ρ=0.60 p<0.020), however, in non-linear regression equation slopes differed for both groups (IUGR 0.164 (95%CI 0.0908-0.238), CTRL 1.183 (95%CI 0.187-2.178)). MS peak areas of ApoCIII species showed deglycosylated apoCIII0 to be significantly higher (p<0.0001), while the glycosylated/sialylated species apoCIII0' (p<0.0039), apoCIII1 (p<0.0001), and apoCIII2 (p<0.0024) were lower in IUGR as compared to CTRL (reference: apoA1). Within the IUGR group we found the singly sialylated variants to be correlated to triglyceride concentrations (apoCIII1 ρ=0.591 p<0.001). This correlation was absent in the CTRL group (ρ=0.14 p<0.34). Similar results were obtained using the Σ apoCIII peak areas as a reference.Our results support a role for apoCIII glycosylation/sialylation in triglyceride metabolism in IUGR. Since increased triglyceride levels are involved in the development of atherosclerosis, apoCIII inhibited triglyceride catabolism may provide a link to the risk of future cardiovascular diseases in IUGR neonates.U. Pecks: None. I. Kirschner: None. M. Wölter: None. N. Maass: None. M.O. Glocker: None. W. Rath: None.