Association of brain injury and neonatal cytokine response during therapeutic hypothermia in newborns with hypoxic-ischemic encephalopathy

BACKGROUND: Cytokines have been proposed as mediators of neonatal brain injury via neuroinflammatory pathways triggered by hypoxia-ischemia. Limited data are available on cytokine profiles in larger cohorts of newborns with hypoxic-ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH). METHODS: Serum cytokines interleukin (IL)-1 beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-13, tumor necrosis factor-alpha, and interferon-gamma were measured in newborns with HIE at 24 and 72 h of TH. Differences between infants with favorable (survivors with mild/no magnetic resonance imaging (MRI) injury) vs. adverse outcome (death or moderate/severe MRI injury) were compared using mixed models to adjust for covariates. RESULTS: Data from 36 term newborns with HIE (favorable outcome: n = 20, adverse outcome: n = 16) were evaluated. Cytokines IL-1 beta, IL-2, IL-6, IL-8, IL-10, and IL-13 were elevated in the adverse relative to favorable outcome group at 24 h. IL-6 remained significantly elevated in the adverse outcome group at 72 h. IL-6 and IL-10 remained significantly associated with outcome group after controlling for covariates. CONCLUSION: Inflammatory cytokines are elevated in HIE newborns with brain injury by MRI. In particular, IL-6 and IL-10 were associated with adverse outcomes after controlling for baseline characteristics and severity of presentation. These data suggest that cytokine response may identify infants in need of additional neuroprotective interventions.