Neurotrophins: Role in Placental Growth and Development.

Neurotrophins, a family of closely related proteins, were originally identified as growth factors for survival, development, and function of neurons in both the central and peripheral nervous systems. Subsequently, neurotrophins have been shown to have functions in immune and reproductive systems. Neurotrophins like nerve growth factor and brain-derived neurotrophic factor (BDNF) are known to play an important role during pregnancy in the process of placental angiogenesis and maturation. Several studies have demonstrated the presence of neurotrophins in the human placenta. The current chapter reviews studies demonstrating the role of neurotrophins during pregnancy particularly in placental development. This chapter also focuses on the regional changes in neurotrophins in the human placenta and its interactions with other growth factors. Future research is needed to understand the mechanisms through which neurotrophins influence the growth and development of the placenta and pregnancy outcome.

Neurotrophin levels in different regions of the placenta and their association with birth outcome and blood pressure.

INTRODUCTION: Our recent study in preeclampsia indicates differential oxidative stress in various regions of the placenta. Oxidative stress is known to influence neurotrophin levels. We therefore hypothesize that placental regional differences in oxidative stress will also lead to differences in neurotrophin levels. METHODS: The current study examines the levels of neurotrophins, brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in different regions of the placenta in 50 normotensive control women and 47 women with preeclampsia (21 delivering at term and 26 delivering preterm). Placentae were collected from four different regions: central maternal (CM), central fetal (CF), peripheral maternal (PM) and peripheral fetal (PF). RESULTS: BDNF levels were higher in CF region as compared to CM (p < 0.01), PM (p < 0.01) and PF (p < 0.05) regions of the placenta in the control group. There was no regional change in NGF levels in any of the groups. Analysis between groups indicated higher NGF levels in CM (p < 0.01), PM (p < 0.05) and PF (p < 0.01) regions of preterm preeclampsia group as compared to control. Negative association of NGF levels in CM, CF and PM regions with baby weight and in CF, PM and PF regions with baby length was observed. NGF levels in all four regions were positively associated with systolic blood pressure. DISCUSSION: Our data indicates regional differences in levels of BDNF only in normotensive control but not in preeclampsia group. Higher NGF levels in preterm preeclampsia may be a response to increased oxidative stress. This may have implications for altered placental development in preeclampsia.