title: MicroRNA-122 can be measured in capillary blood which facilitates point-of-care testing for drug-induced liver injury.
abstract: OBJECTIVE
  Liver-enriched microRNA-122 (miR-122) is a novel circulating biomarker for drug-induced liver injury (DILI). To date, miR-122 has been measured in serum or plasma venous samples. If miR-122 could be measured in capillary blood obtained from a finger prick it would facilitate point-of-care testing, such as in resource-limited settings that have a high burden of DILI.
  
  
  METHODS
  In this study, in healthy subjects, miR-122 was measured by polymerase chain reaction in three capillary blood drops taken from different fingers and in venous blood and plasma (n = 20). miR-122 was also measured in capillary blood obtained from patients with DILI (n = 8).
  
  
  RESULTS
  Circulating miR-122 could be readily measured in a capillary blood drop in healthy volunteers with a median (interquartile range) cycle threshold (Ct) of 32.6 (31.1-34.2). The coefficient of variation for intraindividual variability across replicate blood drops was 49.9%. Capillary miR-122 faithfully reflected the concentration in venous blood and plasma (Pearson R = 0.89, P < 0.0001; 0.88, P < 0.0001, respectively). miR-122 was 86-fold higher in DILI patients [median value 1.0 × 108(interquartile range 1.89 × 107-3.04 × 109) copies/blood drop] compared to healthy subjects [1.85 × 106(4.92 × 105-5.88 × 106) copies/blood drop]. Receiver operator characteristic analysis demonstrated that capillary miR-122 sensitively and specifically reported DILI (area under the curve: 0.96, P = 0.0002).
  
  
  CONCLUSIONS
  This work supports the potential use of miR-122 as biomarker of human DILI when measured in a capillary blood drop. With development across DILI aetiologies, this could be used by novel point-of-care technologies to produce a minimally invasive, near-patient, diagnostic test.
authors.affiliation: Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, Edinburgh University, UK.
authors.forename: A D Bastiaan
authors.initials: ADB
authors.lastname: Vliegenthart
authors.affiliation: Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, Edinburgh University, UK.
authors.forename: Cécile
authors.initials: C
authors.lastname: Berends
authors.affiliation: Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, Edinburgh University, UK.
authors.forename: Carmelita M J
authors.initials: CMJ
authors.lastname: Potter
authors.affiliation: Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Science, Heriot-Watt University, UK.|Division of Infection and Pathway Medicine, University of Edinburgh, UK.
authors.forename: Maiwenn
authors.initials: M
authors.lastname: Kersaudy-Kerhoas
authors.affiliation: Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, Edinburgh University, UK.
authors.forename: James W
authors.initials: JW
authors.lastname: Dear
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D001800:Blood Specimen Collection / Q000379:methods*; D002196:Capillaries / Q000737:chemistry*; D056486:Chemical and Drug Induced Liver Injury / Q000097:blood*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000032:analysis* / Q000097:blood; D008875:Middle Aged; D000067716:Point-of-Care Testing; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D015415:Biomarkers; C531907:MIRN122 microRNA, human; D035683:MicroRNAs
keywords: finger prick; liver toxicity; miR-122; microRNA; point-of-care