Serum mitochondrial biomarkers and damage-associated molecular patterns are higher in acetaminophen overdose patients with poor outcome

Abstract

Acetaminophen (APAP) overdose is a major cause of acute liver failure (ALF). Numerous studies have shown that APAP hepatotoxicity in mice involves mitochondrial dysfunction, and recent data suggest that this is also the case in humans. We have previously shown that glutamate dehydrogenase (GDH), mitochondrial DNA (mtDNA), and nuclear DNA (nDNA) fragments can be measured in circulation of overdose patients as mechanistic biomarkers of mitochondrial damage and damage-associated molecular patterns. In the present study, our aim was to determine whether these biomarkers are higher in serum from nonsurvivors of APAP-induced ALF (AALF), compared to survivors. GDH, mtDNA, and nDNA fragments were measured in serum from AALF patients who did (n = 34) or did not (n = 35) recover. Importantly, all three were significantly increased in patients who died, compared to those who survived (GDH: 450 ± 73 vs. 930 ± 145 U/L; mtDNA: 21 ± 6 vs. 48 ± 13 and 33 ± 10 vs. 43 ± 7 ng/mL for two different genes; nDNA fragments: 148 ± 13 vs. 210 ± 13% of control). Receiver operating characteristic (ROC) curve analyses revealed that nDNA fragments, GDH, and mtDNA were predictive of outcome (area under the curve [AUC], study admission: 0.73, 0.70, and 0.71 or 0.76, respectively, P < 0.05; AUC, time of peak ALT: 0.78, 0.71, and 0.71 or 0.76, respectively, P < 0.05), and the results were similar to those from the Model for End-Stage Liver Disease (MELD; AUC, peak MELD: 0.77; P < 0.05).

Conclusions: Our data suggest that patients with more mitochondrial damage are less likely to survive, demonstrating that mitochondria are central in the mechanisms of APAP hepatotoxicity in humans. Clinically, serum nDNA fragments, GDH, and mtDNA could be useful as part of a panel of biomarkers to predict patient outcome. (Hepatology 2014;60:1336-1345).

© 2014 by the American Association for the Study of Liver Diseases.

Figures

Figure 1

Time course of mitochondrial damage biomarkers in representative patients. Alanine aminotransferase (ALT) (A), glutamate dehydrogenase (GDH) (B), and mitochondrial DNA (mtDNA) (C and D) over time in serum from two representative patients with acetaminophen-induced acute liver injury. S = survivor. NS = non-survivor.

Figure 2

Mitochondrial damage biomarkers were higher in serum from AALF non-survivors on the first study day. Nuclear DNA (nDNA) fragments (A), glutamate dehydrogenase (GDH) (B), mitochondrial DNA (mtDNA) (C) and alanine aminotransferase (ALT) (D) were measured in the first serum sample after study admission from acetaminophen-induced acute liver failure (AALF) patients who did (n = 34) or did not (n = 35) survive. S = survivors. NS = non-survivors. Dot histograms and box plots are shown. Boxes show the median and 25th and the 75th percentiles. Bars show the 10th and the 90th percentiles. *p < 0.05.

Figure 3

Mitochondrial damage biomarkers were higher in serum from AALF non-survivors at the time of peak ALT. Nuclear DNA (nDNA) fragments (A), glutamate dehydrogenase (GDH) (B), mitochondrial DNA (mtDNA) (C) and alanine aminotransferase (ALT) (D) were measured in the first serum sample after study admission from acetaminophen-induced acute liver failure (AALF) patients who did (n = 34) or did not (n = 35) survive. S = survivors. NS = non-survivors. Dot histograms and box plots are shown. Boxes show the median and 25th and the 75th percentiles. Bars show the 10th and the 90th percentiles. *p < 0.05.

Figure 4

Mitochondrial damage biomarkers predict death in AALF patients. Receiver operating characteristic (ROC) curves for nuclear DNA (nDNA) fragments (A), glutamate dehydrogenase (GDH) (B), mitochondrial DNA (mtDNA) (C and D), alanine aminotransferase (ALT) (E) and MELD scores (F). Data are from acetaminophen-induced acute liver failure (AALF) patients who did (n = 34) or did not (n = 35) survive. Either the first sample after study admission (“First”) or the sample drawn nearest to the time of peak ALT (“Peak ALT”) was used. AUC = area under the curve. AUC > 0.5 with p