Current tests for diagnosing liver disease in dogs are sub-optimal. MicroRNA-122 (miR-122) is a sensitive and specific biomarker of liver injury in humans and rodents. Circulating miR-122 could have utility in identifying dogs with liver disease.Objective
Establish the reference interval for miR-122 in healthy dogs and determine performance in a range of dog breeds with liver disease and control animals with non-liver disease.Animals
Stored serum from 120 healthy dogs, 100 dogs with non-liver diseases, and 30 dogs with histologically confirmed liver disease was analyzed.Methods
Retrospective study. Medical records of dogs with liver disease, non-liver disease and healthy dogs were reviewed. Serum miR-122 concentrations were measured by PCR and compared with the characteristics of the dogs and their conventional clinical measurements.Results
In healthy dogs the 2.5th, 50th, and 97.5th quartiles of miR-122 were 110 (90% CI 80–114), 594 (505–682), and 3312 (2925–5144) copies/μL, respectively. There was no difference between healthy dogs and dogs with non-liver disease (median ± IQR: healthy dogs 609 [327–1014] copies/μL; non-liver disease 607 [300–1351] copies/μL). miR-122 was higher in dogs with liver disease (11 332 [4418–20 520] copies/μL, P < .001 compared to healthy dogs). miR-122 identified dogs with liver disease with high accuracy (receiver operating characteristic area under curve for comparison with healthy dogs: 0.93 [95% CI 0.86–0.99]). The upper limit of normal for healthy dogs (3312 copies/μL) had a sensitivity of 77% and specificity of 97% for identifying liver disease.Conclusion and Clinical Importance
Liver disease can be sensitively and specifically diagnosed in dogs by measurement of miR-122.