Brain-Derived Neurotrophic Factor in Infants <32 Weeks Gestational Age: Correlation With Antenatal Factors and Postnatal Outcomes

Neurotrophins (NTs) play important roles in brain growth and development. Cord blood (CB) brain-derived neurotrophic factor (BDNF) concentrations increase with gestational age but data regarding postnatal changes are limited. We measured BDNF concentrations after birth in 33 preterm infants <32 weeks gestation. Serum was collected at birth (CB), at day 2 (D2), between day 6–10 (D6), at day 30 (D30) and at day 60 (D60). BDNF concentrations fell on D2 (p=0.03), recovered by D6 (p=0.10) and continued to rise thereafter at D30 (p=0.06) and D60 (p=0.01) compared to CB. CB BDNF concentrations positively correlated with duration of rupture of membranes (r = 0.43, p=0.04). Antenatal steroids (ANS, p=0.02), postnatal steroids (PNS, p=0.04) and retinopathy of prematurity (ROP, p=0.02) were identified as significant factors in multivariate analyses. The median (25th–75th interquartile range) CB BDNF concentrations were higher in infants who received a complete course ANS compared to those who received a partial course (1461 (553–2064) pg/ml versus 281 (171–536) pg/ml, p= 0.04). BDNF concentrations negatively correlated with the use of PNS at D30 (r = −0.53, p=0.002) and at D60 (r = −0.55, p= 0.009). PNS use was associated with reduced concentrations of BDNF at D30 (733 (101–1983) vs. 2224 (1677–4400) pg/ml, p= 0.004) and at D60 (1149 (288–2270) pg/ml vs. 2560 (1337– 5166) pg/ml, p= 0.01). BDNF concentrations on D60 in infants who developed ROP (n=16) were lower than those who did not develop ROP (n=7) (1417 (553–2540) pg/ml vs. 3593 (2620–7433) pg/ml respectively, p=0.005). Our data suggests that BDNF concentrations rise beyond the first week of age. BDNF concentrations correlate with factors that influence neurodevelopment outcomes.