of IR in the same mice strain, same diet and very similar duration of feeding [41]. Pessin and colleagues demonstrated that, using euglycemic-hyperinsulinemic clamps, the Cyp2e1-null mice were protected substantially against HFD-induced hepatic IR and exhibited better sensitivity of adipose tissue glucose uptake with decrease of hepatic glucose output. Although we did not directly determine hepatic IR while we evaluated the development of systemic IR and GT, it is likely that the WT-HFD group in our study would also have developed earlier hepatic IR than the Cyp2e1-null mice, based on the massive fat accumulation, remarkably higher levels of oxidative stress, OPN, F4/80, and phospho-JNK, which eventually impairs insulin signaling. Nonetheless, with the development of systemic IR, fat accumulation and inflammation will even be greater in the already-primed liver of WT-HFD mice and would accelerate the NASH development, which is the main focus of this study (Supplementary Figure 2).
