Presented at the Neonatal Society 2015 Autumn Meeting.
Ponnusamy V1,2,3, Kapellou O4, Yip E1, Evanson J2, Gupta N5, Ekitzidou G4, Payne V5, Holland N3, Michael-Titus AT6, Yip P6, Shah D1,2
1 Centre of Genomics & Child Health and Centre of Neuroscience & Trauma, Blizard Institute, UK
2 The Royal London Hospital, UK
3 Ashford and St Peter’s Hospitals, UK
4 Homerton University Hospital, UK
5 University Hospital Southampton, UK
6 Centre of Neuroscience, Barts and London School of Medicine and Dentistry, UK
Background: The role of microRNAs (miRNAs) in newborns with hypoxic-ischemic encephalopathy (HIE) treated with therapeutic hypothermia (TH) remains unknown.
1. the expression of two candidate miRNAs, namely miRNA X and miRNA Y varies after HIE in the first five days.
2. the expression differs in cooled newborns with substantial brain injury on MRI, predictive of poor outcome, compared to those without injury.
Methods: With ethics approval (REC13/LO/1378) newborns with HIE were prospectively recruited. Dried blood spots were collected and RNA extracted. Quantitative RT-PCR was performed on the samples collected at day 1, 3 and 5 from cooled babies, to quantify miRNA X and miRNA Y, miRNAs which have been associated with neuronal injury and neuroinflammation, respectively. RNU6B was used as an endogenous control. MR images were assessed independently by two reviewers using the system described by Rutherford et al. (1).
Results: MiRNAs from DBS were studied in 12 newborns with mild HIE who did not fulfil cooling criteria and 20 newborns with moderate-severe HIE who fulfilled the criteria and were cooled. Of the cooled infants, 11 had cerebral MR images predictive of unfavourable outcomes and 9 with predicted favourable outcomes. MiRNA X, which is related to neuroinjury, showed a significantly increased expression from day 1 to day 5 in cooled infants with unfavourable outcomes (p=0.01) (Figure A). The same trajectory was not seen in cooled infants with favourable outcomes (Figure B), or in expression levels of miRNA Y.
Conclusion: We demonstrate increased expression of miRNA X extracted from DBS from day 1 to 5 in cooled newborns with unfavourable outcomes predicted on cerebral MRI. This increase is not seen in cooled newborns with favourable outcomes. The potential role of miRNAs as biomarkers for brain injury in newborns requires further exploration.
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1. Rutherford M, et al. Assessment of brain tissue injury after moderate hypothermia in neonates with hypoxicischemic encephalopathy: a nested substudy of a randomised controlled trial. Lancet Neurol 2010;9:39-45.