Serum retinol binding protein 4 and galectin-3 binding protein as novel markers for postmenopausal nonalcoholic fatty liver disease

ObjectiveTo investigate the differential protein expression before and after menopause in women with nonalcoholic fatty liver disease (NAFLD) and to explore novel markers for menopausal NAFLD.MethodsEight serum samples collected from pre- or post-menopausal women with NAFLD were analysed by iTRAQ 2D-LC-MS/MS. Two protein candidates were selected and verified by enzyme-linked immunosorbent assay (ELISA) in serum samples collected from a one hundred and fifty-three female population subsequently, including 51 in post-menopausal status with NAFLD, 41 in pre-menopausal with NAFLD, 19 healthy individuals in post-menopausal status and 42 healthy pre-menopausal women.ResultsA total of one hundred and sixty-seven proteins exhibiting significant changes were characterized, among which sixty-five were up-regulated and one hundred and two were down-regulated. Of those altered proteins, the expression of serum retinol binding protein 4 (RBP4) and galectin-3 binding protein (LGALS3BP) was obviously increased in the post-menopausal patient group compared to the other. ELISA validations for the two proteins were consistent with the proteomic profiling.ConclusionsSerum RBP4 and LGAL3BP were up-regulated after menopause under NAFLD conditions, which suggested the two proteins may be potential markers as NAFLD in postmenopausal population.