A study of microRNAs from dried blood spots in newborns after perinatal asphyxia: a simple and feasible biosampling method

Abstract

Background:The potential of microRNAs (miRNAs) as bedside biomarkers in selecting newborns with hypoxic-ischemic encephalopathy (HIE) for neuroprotection has yet to be explored. Commonly, blood-based biomarker tests use plasma or serum which don't allow evaluation of both intracellular and extracellular changes. Methods:We describe a technique to extract and compare expression of miRNAs from a single small 6-mm-diameter dried blood spot (DBS) stored at room temperature with those from EDTA-blood, plasma, and urine. Three miRNAs (RNU6B, let7b, and miR-21) were quantified via extraction and quantitative RT-PCR performed from a DBS and compared with levels from EDTA-blood, plasma, and urine. Secondarily, candidate miRNAs let7b, miR-21, miR-29b, miR-124, and miR-155 in DBS were evaluated as potential biomarkers for HIE. results: Candidate miRNAs were extractable in all biosamples from newborns, with the highest expression in DBS. There was a good correlation between miRNAs' levels in DBS and EDTA-blood at −80 °C. No significant difference was observed in the miRNA levels between the favorable and unfavorable outcome groups for babies with HIE. conclusion: DBS may be useful for studying the potential of miRNAs as biomarkers for brain injury.

Temporal Profile of Circulating microRNAs after Global Hypoxia-Ischemia in Newborn Piglets

“…However, our findings do not support its potential. Ponnusamy et al [8] could neither demonstrate that miR-124 levels were able to differentiate between asphyxiated newborns with favorable and unfavorable outcomes. Although it has previously been shown that miR-124 correlates with brain injury in mature pigs [23], the expression of miRNA in newborns might be distinctive.…”

“…In the setting of neonatal hypoxia-ischemia (HI) only a limited number of studies have yet investigated miRNA [6,7,8,9]. Among others, Ma et al [9] have studied miRNA after hypoxic-ischemic brain injury in a rodent model of HI encephalopathy (HIE).…”

“…In the setting of fetal hypoxia Whitehead et al [6] found selected miRNAs to be altered in maternal blood. Looney et al [7] found significantly lower expression of miR-374a in umbilical cord blood of asphyxiated infants who developed HIE, and recently Ponnusamy et al [8] demonstrated the feasibility of analyzing miRNA in biosamples of dried blood spots from newborns suffering perinatal asphyxia. …”

Increase of neuronal injury markers Tau and neurofilament light proteins in umbilical blood after intrapartum asphyxia

“…Therefore, there is a renewed interest in the development of biomarkers that can predict the risk of brain injury and aid in the selection of cases that should be offered therapy. Previous reports show that MRI/MRS (5) as well as multiple biochemical biomarkers in cerebrospinal fluid or neonatal blood hours to days after birth are elevated after moderate and severe asphyxia at least if there is development of HIE (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). However, there is a scarcity of biomarkers detectable in readily accessible body fluids such as umbilical blood early enough to be useful for directing therapy (17).…”

Dried Blood Spot RNA Transcriptomes Correlate with Transcriptomes Derived from Whole Blood RNA

“…3 Methods to isolate RNA of acceptable integrity and quantity from DBS have been explored. Several studies have used DBS-sourced messenger RNA (mRNA) or micro RNA for targeted gene expression studies [4][5][6] or microarray. 7,8 For next-generation sequencing, some studies have used a pre-amplification step to generate sufficient mRNA for array studies, [9][10][11] although preamplification steps can introduce bias.…”