Placental and cord blood brain derived neurotrophic factor levels are decreased in nondiabetic macrosomia.

Abstract

To measure levels of placental brain derived neurotrophic factor (BDNF) gene expression and umbilical cord blood BDNF in neonates with nondiabetic macrosomia and determine associations between these levels and macrosomia. This case-control study included 58 nondiabetic macrosomic and 59 normal birth weight mother-infant pairs. Data were collected from interviews and our hospital's database. BDNF gene expression was quantified in placental tissues using quantitative real-time polymerase chain reaction (n=117). Umbilical cord blood BDNF levels were measured by enzyme-linked immunosorbent assay (n=90). Multivariate logistic regression models were used to evaluate associations between BDNF levels and macrosomia. Placental BDNF gene expression (P=0.026) and cord blood BDNF (P=0.008) were lower in neonates with nondiabetic macrosomia than in normal birth weight controls. Cord blood BDNF was significantly lower in vaginally delivered macrosomic neonates than vaginally delivered controls (P=0.014), but cord BDNF did not differ between vaginal and cesarean section delivery modes in macrosomic neonates. Cord blood BDNF was positively associated with gestational age in control neonates (r=0.496, P<0.001), but not in macrosomic neonates. Cord blood BDNF was positively associated with placental BDNF relative expression (r s=0.245, P=0.02) in the total group. Higher cord blood BDNF levels were independently associated with protection against nondiabetic macrosomia (adjusted odds ratio 0.992; 95% confidence interval 0.986-0.998). Both placental BDNF gene expression and cord blood BDNF were downregulated in neonates with nondiabetic macrosomia compared with normal birth weight neonates. Cord BDNF may partly derive from BDNF secreted by the placenta. Higher cord plasma BDNF levels protected against nondiabetic macrosomia.