Measurement of Serum Acetaminophen–Protein Adducts in Patients With Acute Liver Failure

University of Pittsburgh, Pittsburgh, Pennsylvania, United States
Gastroenterology (Impact Factor: 16.72). 04/2006; 130(3):687-94. DOI: 10.1053/j.gastro.2006.01.033
Source: PubMed


Acetaminophen toxicity is the most common cause of acute liver failure (ALF) in the United States and Great Britain, but may be underrecognized in certain settings. Acetaminophen-protein adducts are specific biomarkers of drug-related toxicity in animal models and can be measured in tissue or blood samples. Measurement of serum adducts might improve diagnostic accuracy in acute liver failure (ALF) patients.
We measured serum acetaminophen-protein adducts using high-pressure liquid chromatography with electrochemical detection in coded sera of 66 patients with ALF collected prospectively at 24 US tertiary referral centers. Samples were included from 20 patients with well-characterized acetaminophen-related acute liver failure, 10 patients with ALF owing to other well-defined causes, 36 patients with ALF of indeterminate etiology, and 15 additional patients without ALF but with known acetaminophen overdose and minimal or no biochemical liver injury.
Acetaminophen-protein adducts were detected in serum in 100% of known acetaminophen ALF patients and in none of the ALF patients with other defined causes, yielding a sensitivity and specificity of 100%. In daily serial samples, serum adducts decreased in parallel with aminotransferase levels. Seven of 36 (19%) indeterminate cases demonstrated adducts in serum suggesting that acetaminophen toxicity caused or contributed to ALF in these patients. Low adduct levels were present in 2 of 15 patients with acetaminophen overdose without significant liver injury.
Measurement of serum acetaminophen-protein adducts reliably identified acetaminophen toxicity, and may be a useful diagnostic test for cases lacking historical data or other clinical information.

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    • "The role of ASK1 and JNK activation during APAP overdose in humans remains unclear. More recent translational studies support the hypothesis that protein adduct formation and mitochondrial dysfunction are important for the human pathophysiology (Davern et al., 2006; McGill et al., 2012, 2014). Although APAP causes extensive JNK activation and mitochondrial p-JNK translocation in primary human hepatocytes , the protection by inhibition of JNK was modest (Xie et al., 2014). "
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    • "APAP-protein adducts could accumulate over time since they are more persistent than APAP metabolites. APAP-protein adduct half-life was evaluated at 1–2 days in human plasma after acute overdoses of APAP [22] [23] but is still unknown in liver. To our knowledge, APAP-protein adducts and other protein modifications have never been deeply investigated in the liver after chronic treatments with non-toxic doses of APAP. "
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    • "Early studies of APAP protein adducts relied on radiometric [24] [34] and immunochemical [26,35–39] methods for qualitative and quantitative detection. Muldrew et al. later developed a sensitive high-performance liquid chromatography-electrochemical detection (HPLC-ECD) assay that obviated the use of radiolabeled drug or antibodies [27] [30]. The actual analyte detected by the assay was a biomarker of APAP protein adducts, protein-derived 3- (cystein-S-yl)-acetaminophen (or acetaminophen-cysteine, APAP- Cys). "
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