Endothelial dysfunction and developmental outcomes of very low birth weight newborns with hypoxic encephalopathy

Objective: To investigate the levels of endothelial constricting and dilating mediators in preterm infants with hypoxic-ischaemic encephalopathy and prospectively evaluate the association between levels measured during the perinatal period and the diagnosis of neurodevelopmental disorders at 3 years of age.

Methods: This regional observational cohort study was conducted at the Azerbaijan Medical University, Baku, Azerbaijan, from November 2011 to January 2013, and comprised very-low-birth-weight infants admitted to the intensive care unit during the perinatal period. Blood concentrations of nitric oxide, endothelin-1 and endothelial nitric oxide synthase were measured on days 1-3 and 5-7 of the neonatal period. Concentrations of neuron-specific enolase and antibodies against N-methyl-D-aspartate glutamate receptors were measured in peripheral blood samples for detection of brain damage in the early neonatal period of life. The infants were divided in 3 different groups: those diagnosed with moderate-to-severe neurodevelopmental disorders or cerebral palsy were included in the first group; those with mild neurologic changes were in the second group; and children without evidence of neurological impairment were in the third group. The fourth group comprised controls. SPSS 20 was used for data analysis.

Results: Of the 62 participants, there were 8(12.9%) in the first group, 20(32.3%) in second, 14(22.6%) in third and 20(32.3%) in the control group. The activity of endothelial nitric oxide synthase was reduced and nitric oxide concentrations were increased in the first group compared to those in the third group (p<0.05). Deep endothelial nitric oxide synthase depression and insufficient endothelin-1 synthesis were associated with diagnosis in the first group (p<0.05). No differences in concentrations of neuron-specific enolase and NR2 antibodies were identified among infants with and without a subsequent diagnosis of neurodevelopmental disorders (p>0.05).

Conclusions: The association between depressed endothelial nitric oxide synthase activation and insufficient endothelin-1 synthesis in the early days of life of very-low-birth-weight infants might be one of the causes of more serious and irreversible injury of brain tissue.