Metabolomic Characterization of a Novel Pig Model of Pediatric Non-alcoholic Fatty Liver Disease (P08-131-19)

Abstract

Objectives Non-alcoholic fatty liver disease (NAFLD) is a leading nutrition-linked liver disease in children. We have recently identified the neonatal Iberian pig as a novel model of pediatric NAFLD. Interestingly, feeding a high fructose-high fat (HFF) diet to neonatal Iberian pigs for 10 weeks did not induce obesity and decreased high and low density lipoproteins in serum, while the liver exhibited many of the histological features of pediatric NAFLD. In this study we utilized a metabolomics approach to characterize the metabolic phenotype of this pig model. Methods Plasma and liver samples collected from Iberian pigs fed control, HFF, control + probiotic and HFF + probiotic diets were analyzed by LC-MS using targeted assays for primary metabolomics, aminomics, and lipidomics. Data was analyzed with multivariate statistics and 2-way ANOVA with t-tests adjusted for false discovery rate. Results Results from multivariate tests indicated no diet × probiotic interaction or probiotic effect, so only the main effect of diet is shown. A total of 224 and 218 metabolites were identified in the plasma and liver, respectively. In agreement with previous NAFLD models, the HFF diet increased hepatic branched chain amino acids, cholesteryl esters, hydroxyproline, plasma acylcarnitines and primary bile acids, and altered hepatic triacylglycerol-species composition (P < 0.0001). In addition, HFF pigs had increased homocysteine and methionine levels combined with a decrease in pyridoxate in liver (P < 0.0001), suggesting a disruption in the one carbon cycle and its methyl donation capability. HFF decreased hepatic choline and betaine (P < 0.0001), which may indicate a compensatory use of the methyl groups of these compounds. The aforementioned reduction of choline used for the CDP-choline pathway and the potential one carbon cycle impact on SAM availability for the phosphatidylethanolamine N-methyltransferase (PEMT) pathway may explain the observed differential changes in hepatic phosphatidylcholines (P < 0.0001), which are required for the production of very low density lipoproteins (VLDL). Conclusions Unique features of this model such as reduced plasma lipoproteins and lack of weight gain in the presence of hepatic steatosis may be related to an altered one carbon cycle impacting phosphatidylcholine production. Funding Sources ARI, AcornSeekers.

The Neonatal and Juvenile Pig in Pediatric Drug Discovery and Development

“…This is also related to the fact that pediatric obesity and nonalcoholic fatty liver disease (NAFLD) are on the rise in developed countries. In recent years, juvenile Iberian and Ossabaw pigs are put forward as large animal models to study both disorders which can be elicited via challenging these pigs with a Western diet [ 233 , 234 , 235 ]. Although rodent models are typically used to study adult obesity and NALFD, they have limited use in studying the mechanisms of these diseases in infants and children.…”