1873-P: NAFLD and Insulin Resistance Is Associated with a Specific Signature in Membrane Phospholipid Metabolites in Adolescents with Polycystic Ovary Syndrome (PCOS)

Abstract

Obese adolescents with PCOS are at high risk of nonalcoholic Fatty Liver Disease (NAFLD) which contributes to the risk of diabetes. Impaired hepatic energy metabolism is associated with diabetes and characterized by decreased inorganic phosphates (Pi) and ATP hepatic content. Membrane phospholipids measured by magnetic resonance spectroscopy (MRS) may reflect endoplasmic reticulum (ER) stress (phosphodiesters; PDE) or turnover/composition of membrane phospholipids: precursors (phosphomonoesters (PME): phosphoethanolamine (PE) and phosphocholine (PC)) and degradation products (PDE). It is not known if adolescents with PCOS and NAFLD have impaired hepatic energy metabolism or MRS signature associated with insulin sensitivity (Si). Obese adolescents with PCOS (n=25) underwent fasted hepatic 31phosphorus-MRS to measure ATP, Pi, PME and PDE relative to total phosphates (TP). Liver stiffness was measured with MR elastography and hepatic fat fraction (HFF) by MRI-proton density, with an HFF >5.5% classified as NAFLD. A 6h oral sugar tolerance test (OSTT, 25g fructose+75g glucose) was performed. Insulin sensitivity (Si) was calculated with the oral minimal model. 12 girls (BMI 36.4 ±7.3 kg/m2, age 16 (15-17)) had NAFLD and 13 did not (BMI 34.0±4.9 kg/m2, age 16 (14-17)). PME/TP were lower in girls with NAFLD (p=0.007) as well as the ratio of PME/PDE (p=0.002). A lower PE/TP was associated with higher liver stiffness (r= -0.55; p=0.009) and lower Si (r=0.57; p= 0.03). Total ATP/TP, y-ATP/TP and Pi/TP were similar between groups (p>0.15). Obese adolescents with PCOS and NAFLD have a distinct signature in hepatic 31P-MRS that is associated with Si suggesting alterations in membrane phospholipids. However, changes in energetics seen in adults with NAFLD are not present. Further work is needed to understand how these changes in hepatic phospholipids relates to insulin sensitivity and risk for diabetes. Disclosure A. Carreau: Advisory Panel; Self; Pfizer Inc. Y. Garcia Reyes: None. B. Newcomer: None. D.E. Befroy: None. M.S. Brown: None. M. Cree-Green: None. Funding National Institutes of Health (K23DK107871); Doris Duke Charitable Foundation; National Center for Advancing Translational Sciences (UL1TR002535); Diabetes Canada