The Role of Insulin-like Growth Factor-Axis and Mitotic Index in South Indian Neonates with Small for Gestational Age

Abstract

Objective IGF-axis and mitotic capacity of cells play a vital role in fetal growth. We compared IGF1, IGF2, and IGFBP3 protein levels, mitotic indices, IGFR1 and IGFR2 mRNA expression in appropriate for gestational age (AGA) and small for gestational age (SGA) neonates of Indian women. Methods Cord blood (n = 80) and placental samples (n = 40) were collected from AGA and SGA neonates. Plasma IGF1, IGF2, and IGFBP3 proteins were measured by ELISA. IGFR1 and IGFR2 mRNA expression in the placenta were analyzed by qRT-PCR. Cord blood was cultured in vitro and mitotic index was obtained. Results IGF1 (p = 1), and IGF2 (p = 0.69) protein levels did not differ, whereas IGFBP3 (p = 0.02) was significantly less in SGA compared to AGA neonates. Down-regulation of IGFR1 (3.9-folds) and IGFR2 (2.8-folds) mRNA and reduced mitotic index of lymphocytes was observed in SGA (p = 0.001) compared to AGA neonates. Conclusion Our results showed that, SGA neonates displayed down-regulated IGFR1 and IGFR2 mRNA, decreased IGFBP3 protein and mitotic index.