Association of brain-derived neurotrophic factor and tyrosine kinase B receptor in pregnancy.

Abnormal brain development in a compromised prenatal and/or early postnatal environment is thought to be a risk factor for several neurobehavioural disorders. However, the mechanisms underlying these are not well understood. We have earlier reported reduced placental docosahexaenoic acid (DHA) levels in preterm deliveries. We have hypothesized that increased oxidative stress and reduced DHA levels may lead to changes in the circulating levels of maternal and cord brain-derived neurotrophic factor (BDNF) and its receptor tyrosine kinase B (TrkB) levels. A total number of 96 women delivering preterm and 95 women delivering at term were recruited. Plasma BDNF levels were measured in both mother and cord blood plasma using the BDNF Immuno Assay kit. Placental TrkB levels were analysed using sandwich enzyme-linked immunosorbent assay (ELISA). Maternal plasma BDNF levels and placental TrkB levels were higher (p<0.05) while cord plasma BDNF levels were lower (p<0.01) in women delivering preterm as compared to term. There was a negative association between levels of placental TrkB and DHA (p=0.034). A negative association between maternal plasma BDNF levels and placental weight (p=0.001) was observed while a positive association was seen between cord plasma BDNF levels and gestation (p=0.025). The reduction in cord BDNF levels may have implications for altered neurodevelopment in childhood and later life. Studies need to be undertaken to follow up children born preterm for risk of neurobehavioural disorders like attention deficit hyperactivity disorder (ADHD) to understand the effect of altered BDNF at birth on neurodevelopment.