Differential gene expression of somatotrophic and growth factors in response to in vivo hypoxia in human placenta

OBJECTIVE: Hypoxia-inducible transcription factors (HIFs) have been characterized as the most important regulators of O-2-dependent gene transcription. We investigated expression of HIF-dependent growth factors and HIF-independent somatotrophic factors in term placenta in response to hypoxic ischemia. STUDY DESIGN: Our cross-sectional in vivo analysis included term placentas of gestations complicated by the following: ( 1) birth asphyxia (n = 22); ( 2) chronic hypoxic ischemia ( n = 22); and ( 3) controls ( n = 28). Gene expression of leptin, insulin-like growth factor (IGF)-1, IGF-2, ghrelin, and human placental growth hormone (hPGH) were measured by Taq-Man reverse transcriptase-polymerase chain reaction. RESULTS: Acute and chronic hypoxia significantly increased leptin messenger ribonucleic acid ( mRNA) levels, compared with controls (P <.001). Augmented IGF-2 mRNA levels were present in chronic hypoxia ( P <.001) but not in birth asphyxia. IGF-1, ghrelin, and hPGH mRNA levels did not change in relation to hypoxia. CONCLUSION: IGF-2 and leptin are suggested to be involved in adaptive response to hypoxic ischemia in term placenta with differential transcriptional regulation related to the duration of hypoxia.