The role of urine metabolomics among newborn infants with hypoxic ishaemic encephalopathy: a literature review

Abstract
Background: Perinatal asphyxia (PA) which may result in hypoxic ischaemic encephalopathy (HIE) affects four million neonates worldwide and accounts for the death of one million of affected babies. The science of metabolomics has become an area of growing interest in neonatal research, with a potential role in identifying useful biomarkers that can accurately predict injury severity in perinatal asphyxia and HIE. The aim of this review is to look at the evidence of the usefulness of urine metabolomics in predicting outcome in PA/HIE. Methods: The key words used in the advanced search ‘urine metabolomics’ AND ‘perinatal asphyxia’ OR ‘hypoxic ischaemic encephalopathy’, yielded 13 articles. Results: Of the selected thirteen studies, 38% (n = 5) were human studies, 31% (n= 4) were animal studies and 31% (n = 4) were review articles. The studies confirmed the involvement of known pathways in the development of PA/HIE, primarily the Krebs cycle evidenced by accumulation of TCA cycle intermediates (citrate, α-ketoglutarate, succinate) and anaerobic pathways indicated by increased lactate. Other pathways involved include amino acid and carbohydrate pathways. Conclusion: Metabolomic studies so far are promising in highlighting potential biomarker profiles in PA/HIE. Further research is necessary to further clarify the role of identified metabolites in predicting outcome and prognosis in neonates affected by PA/HIE.