Correlation of Plasmatic Profiles of Inflammatory Cytokines/Chemokines and GFAP with Brain Damage Detected at MRI in Neonates with Hypoxic Ischemic Encephalopathy (HIE) Treated with Therapeutic Hypothermia: A Preliminary Study

Abstract

Background & Objective. Perinatal hypoxia acutely triggers the release of cytokines and chemokines from neurons, astrocytes and microglia. In response to hypoxia-ischemia resting/ramified microglia proliferate and undergo activation, with the production of proinflammatory molecules. The brain damage extension seems to be related with both the severity of hypoxia and the balance between pro and anti-inflammatory host response. Methods: In this preliminary study we compared in 10 neonates with hypoxic ischemic encephalopathy (HIE), during therapeutic hypothermia (TH), plasmatic cytokines and other inflammatory molecules levels: monocytic chemotactic-protein-1 (CCL2/MCP-1), CXCL8, glial fibrillary acidic protein (GFAP), Interferon gamma (IFN y), Interleukin 10 (IL-10), IL-18, IL-6, CCL3, ENOLASE2, Colony Stimulating Factor(GM-CSF), IL-1b, IL-12p70, IL-33, Tumor Necrosis Factor alpha(TNF), collected at four different time points during TH (24 hours, 25-48 hours, 49-72 hours) , and after the rewarming (7-10 days from birth). Five of enrolled babies had pathological brain MRI (“cases”) and 5 had a normal examination (“controls”). Cytokines were measured by Magnetic Luminex Assay (Luminex SV 013-17 (14), instrument Biorad Bio-Plex 100 s.n. LX 10005039304). MRI images were classified according to the Barkovich score. Results: Mean levels of all cytokines and molecules at time T1 were not significantly different in the two groups of patients. Comparing samples paired by day of collection, the greatest differences between cases and controls were found at times T2 and T3, during TH. After rewarming, some molecules showed an upward trend. At T4, levels tended to be close again (with the exception of IL-6, IL10 and IL18). Infants with worse MRI showed plasmatic GFAP levels higher than those with normal MRI, while their IL-18 was lower. Mean levels of CCL3MIP1alpha, GMCSF, IL1BETA overlapped throughout the observation period in both the groups of neonates. Conclusion. In children with worse brain MRI we found high levels of GFAP and of IL-10 at T4, considered respectively an early biomarker of brain damage and a predictor of adverse outcome, according to the literature, and a trend towards low IL-18 levels. We found the greatest, although not significant, difference between molecules levels in cases and controls at time points T2 and T3, during TH. With the rewarming some molecules showed an upward trend. We cannot exclude that the small sample size may prevent significance in the differences from being achieved.