Sensitivity to hepatotoxicity due to epigallocatechin gallate is affected by genetic background in diversity outbred mice

Abstract

Consumer use of herbal and dietary supplements has recently grown in the United States and, with increased use, reports of rare adverse reactions have emerged. One such supplement is green tea extract, containing the polyphenol epigallocatechin gallate (EGCG), which has been shown to be hepatotoxic at high doses in animal models. The Drug-Induced Liver Injury Network has identified multiple patients who have experienced liver injury ascribed to green tea extract consumption and the relationship to dose has not been straightforward, indicating that differences in sensitivity may contribute to the adverse response in susceptible people. The Diversity Outbred (DO), a genetically heterogeneous mouse population, provides a potential platform for study of interindividual toxicity responses to green tea extract. Within the DO population, an equal exposure to EGCG (50 mg/kg; daily for three days) was found to be tolerated in the majority of mice; however, a small fraction of the animals (16%; 43/272) exhibited severe hepatotoxicity (10-86.8% liver necrosis) that is analogous to the clinical cases. The data indicate that the DO mice may provide a platform for informing risk of rare, adverse reactions that may occur in consumer populations upon ingestion of concentrated herbal products.

Keywords: Diversity outbred; Epigallocatechin gallate; Green tea; Hepatotoxicity; Herbal; Population variability.

Fig. 1

Baseline and terminal ALT concentrations (A) and resulting fold change (B, terminal concentration to pre-dose concentration) were quantified in serum samples obtained from DO mice treated with 50 mg/kg/day EGCG for three consecutive days. Each black dot represents an individual EGCG-treated animal. Bars shown in (A) represent the mean ± SEM ALT concentration and significance between groups was P < 0.05.

Fig. 2

(A) Percent liver necrosis was scored for each animal using an unbiased point scoring method. (B) Representative photomicrographs are shown for the left liver lobe stained with H&E sections at 200× magnification. The dose administered and the percent liver necrosis score are indicated above each image. (C) Percent TUNEL positive area is shown for each animal from the left liver lobe. In panels (A) and (C), each dot represents the endpoint value for an individual DO mouse treated with 50 mg/kg EGCG.

Fig. 3

(A) Terminal serum ALT concentrations are shown for individual DO mice treated with 30 mg/kg/day or 50 mg/kg/day EGCG for three consecutive days. Error bars represent the SEM. *P < 0.05. ALT fold change (terminal to baseline) in DO animals treated with (B) 30 mg/kg/day EGCG or (C) or 50 mg/kg/day EGCG is shown with the dotted line indicating a three-fold change.

Fig. 4

(A) A Manhattan plot is shown for significance scores resulting from QTL mapping of ALT fold change in DO mice dosed with EGCG. The red circle indicates a QTL identified on Chr 4. (B) The coefficient effect plot indicates the contribution of each cofounder haplotype to the QTL support interval. (C) Expanded Manhattan plot is shown for Chr 4. The red bar shows the QTL falling between 142.591722 and 151.777278 Mb. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)