Elevated Serum Neurofilament Light Chain Is Associated With Systemic Inflammation in Very Preterm Infants

AIM: Neurofilament light chain (NFL) and glial fibrillary acidic protein (GFAP) are known biomarkers of brain injury in adults, but their significance in very preterm (VPT) infants remains unclear. Given the strong link between inflammation, oxidative stress, and brain injury in this population, we investigated associations between NFL, GFAP, and inflammatory and oxidative stress markers in VPT infants. METHODS: As part of the prospective Finnish PreBaby study on metabolism in VPT infants, serum NFL and GFAP levels were measured at three timepoints from birth to term-equivalent age (TEA) to assess their associations with IL-6 protein levels depicting inflammation, oxidative stress marker urinary 8-isoprostane, and postmenstrual age (PMA). RESULTS: Serum NFL levels showed a strong positive correlation with IL-6 levels (Spearman correlation coefficient 0.784, p < 0.001). Higher NFL concentrations were associated with lower PMA and decreased towards TEA. A weaker correlation was observed between NFL and the oxidative stress marker 8-isoprostane. Serum GFAP levels were not associated with inflammation. CONCLUSIONS: Serum levels of neurofilament light chain are linked to inflammation in very preterm infants. The potential of NFL as an early biomarker of brain injury, potentially guiding preventive interventions and therapy in very preterm infants, should be investigated further.