Quantitative and qualitative changes in adiponectin during pregnancy in AGA and IUGR newborns

Abstract

IN AGA AND IUGR NEWBORNS SHALI MAZAKI TOVI, HANNAH KANETY, EYAL SCHIFF, RINA HEMI, ANN SHOHAM, ELEANOR BIRENBOIM, CLARA PARIENTE, EYAL SIVAN, Department of Obstetrics and Gynecology,Sheba Medical Center, Tel Hashomer, Israel, Institute of Endocrinology, Sheba medical center, Tel Hashomer, Israel OBJECTIVE: Adiponectin, an adipocyte-derived plasma protein, with insulinsensitizing properties, is negatively correlated with obesity and insulin resistance in adults. Adiponectin in plasma is found in distinct forms: trimer, hexamer and a high molecular weight (HMW) species. The aim of this study was to evaluate adiponectin levels in appropriate for gestational age (AGA) and intrauterine growth restricted (IUGR) newborns and to characterize the alterations of fetal adiponectin isoforms throughout pregnancy and in the two groups. STUDY DESIGN: Adiponectin, leptin and insulin levels, were measured (by RIA) in cord blood samples obtained from 80 newborns at delivery between 25 and 42 weeks of gestation. Of this group, 45 AGA (mean percentile 55.0 G 26.3) and 21 IUGR (5.4 G 2.4) newborns, were compared for their adiponectin and leptin and insulin concentrations. In addition, cord blood samples were analyzed for adiponectin isoforms by SDS-PAGE under nondenaturing conditions. RESULTS: Adiponectin was found in cord blood of all newborns in levels ranging from 1-118 mg/mL and positively correlated with the gestational age (r = 0.65, P ! .01). Adiponectin levels in the AGA group were significantly higher compared with the IUGR group (68.2 G 14.5 mg/mL and 48.5 G 2 0.9 mg/mL, respectively, P ! .0001). Similarly, leptin levels were significantly lower in the IUGR group (10.6 G 7.7 vs. 5.6 G 5.6 ng/mL; P ! .006). The trimer and hexamer isoforms of adiponectin were the prevalent species in serum samples from 25-35 weeks of gestation, and in IUGR group, while in later gestational weeks and in AGA group, the HMW form predominated. CONCLUSION: These findings indicate that adiponectin is produced in the fetus as early as 25 weeks of gestation, and increases with gestational age, potentially reflecting the development of adipose tissue. The quantitative and qualitative (isoforms) changes in adiponectin throughout pregnancy and between IUGR and AGA groups may suggest a putative role of adiponectin in physiological and pathological fetal growth. SMFM Abstracts S163