LAUSR

Abstract Purpose: Circulating microRNAs represent a reservoir for biomarker discovery. Our objective was to profile the change in human circulating microRNA associated with recreational use of alcohol at a social event. Material and methods: Blood was collected from healthy volunteers (N = 16) before and after recreational consumption of alcohol (ethanol). Biochemistry, hematology and ethanol measurements were performed. The change in the serum small RNA fraction was quantified by RNA sequencing. Results: Blood ethanol was undetectable at study entry in all subjects [<10 mg/dL]. After consuming alcohol the median concentration was 89 mg/dL [IQR: 71–138. Min–max 20–175]. There were no changes in biochemistry and hematology parameters. Serum RNA sequencing identified 1371 small RNA species (1305 microRNAs). There were significant increases [adjusted p-value <0.05, fold increase 2 or more] in 265 microRNAs, around a fifth of the total [median fold increase 2.3 [IQR: 2.1–2.5; Max: 3.7]]. miR-185-5p decreased following alcohol exposure [adjusted p-value <0.05, fold decrease 2 or more]. Conclusions: The microRNA composition of human serum is dynamic and environmental factors may have a significant impact. Within its context of use the fold change ‘signal’ of a microRNA must be large enough to negate the risk of false results due to background ‘noise’.