Advanced molecular biologic techniques in toxicologic disease

Circulating microRNA Profiles in Acetaminophen Toxicity

INTRODUCTION

Acetaminophen toxicity has been associated with elevation of microRNAs. The present study was to evaluate overall microRNA profiles and previously identified microRNAs to differentiate acetaminophen (APAP) toxicity from other causes of transaminase elevation.

METHODS

This was an observational study of adults with presumed acetaminophen toxicity at presentation. Serum samples were collected every 12 hours during hospitalization. Total miRNAs were extracted from plasma and levels of 327 microRNAs were quantified using real-time polymerase chain reaction. A standard measure of miRNA expression (delta-delta cycle threshold) was calculated for each microRNAs. A two-level cluster analysis was performed using a random k-means algorithm. Demographic and clinical characteristics of each cluster were compared using ANOVA, Wilcoxon rank sum, Kruskal-Wallis, and chi-square tests. Performance of specific miRNAs of interest was also evaluated.

RESULTS

Twenty-seven subjects were enrolled (21 with a final diagnosis of acetaminophen toxicity), and a total of 61 samples were analyzed. Five clusters were identified, two of which demonstrated clear clinical patterns and included specific elevated miRNAs previously reported to be elevated in APAP toxicity patients. Features associated with clusters 1 and 5 included confirmed acetaminophen toxicity, high peak alanine aminotransferase, and late presentation. Clusters 2-4 contained lower peak microRNAs, lower peak alanine aminotransferase, and heterogeneous clinical characteristics.

CONCLUSIONS

Severe cases of acetaminophen toxicity showed two distinct patterns of microRNA elevation which were similar to previous work, while less severe cases were difficult to distinguish from non-acetaminophen-associated cases. Further work is needed to incorporate microRNA profiles into the diagnostic algorithm of acetaminophen toxicity.