Adipocyte Fatty Acid-Binding Protein 4 is Altered in Growth Discordant Dichorionic, but not in Monochorionic Twins

CONTEXT: The fetal period has a critical and long-lasting impact on the regulation of metabolic processes and a life-long predisposition for obesity and metabolic syndrome. The exact mechanisms are unknown, but epigenetic regulation likely plays a major role. Twins represent an excellent model to study these mechanisms, as they share the same intrauterine environment and similar or even the same genetic information. We examined cord blood levels of adipocyte fatty-acid binding protein 4 (A-FABP or FABP4), a novel adipokine correlated with obesity and metabolic disease in children and adults. OBJECTIVE: To examine A-FABP levels in the cord blood of twins with concordant and discordant growth and in singletons with intrauterine growth restriction (IUGR). DESIGN: Cohort study of 36 twin pairs (25 growth concordant and 11 growth discordant), and 42 singleton pregnancies (28 IUGR and 13 normally grown controls, 1 HELLP). OUTCOME MEASURES: Cord blood A-FABP levels measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: A-FABP levels were higher in the smaller of growth discordant dichorionic (DC) twins versus their co-twins (109.46 ± 62.80 ng/mL vs. 72.93 ± 36.66 ng/mL, P = 0.028). A-FABP was negatively correlated with birth weight and gestational age (P < 0.001), but not with birth weight z-score (P = 0.37). CONCLUSIONS: Increased A-FABP levels might be associated with an increased metabolic risk in growth-restricted (twins) and prematurely born infants.