Summary Metabolomic profiling of obese versus lean humans reveals a branched-chain amino acid (BCAA)-related metabolite signature that is suggestive of increased catabolism of BCAA and correlated with insulin resistance. To test its impact on metabolic homeostasis, we fed rats on high-fat (HF), HF with supplemented BCAA (HF/BCAA) or standard chow (SC) diets. Despite having reduced food intake and weight gain equivalent to the SC group, HF/BCAA rats were equally insulin resistant as HF rats. Pair-feeding of HF diet to match the HF/BCAA animals or BCAA addition to SC diet did not cause insulin resistance. Insulin resistance induced by HF/BCAA feeding was accompanied by chronic phosphorylation of mTOR, JNK, and IRS1(ser307), accumulation of multiple acylcarnitines in muscle, and was reversed by the mTOR inhibitor, rapamycin. Our findings show that in the context of a poor dietary pattern that includes high fat consumption, BCAA contributes to development of obesity-associated insulin resistance.

Background & Aims Idiosyncratic drug-induced liver injury (DILI) is among the most common causes of acute liver failure in the United States, accounting for approximately 13% of cases. A prospective study was begun in 2003 to recruit patients with suspected DILI and create a repository of biological samples for analysis. This report summarizes the causes, clinical features, and outcomes from the first 300 patients enrolled. Methods Patients with suspected DILI were enrolled based on predefined criteria and followed up for at least 6 months. Patients with acetaminophen liver injury were excluded. Results DILI was caused by a single prescription medication in 73% of the cases, by dietary supplements in 9%, and by multiple agents in 18%. More than 100 different agents were associated with DILI; antimicrobials (45.5%) and central nervous system agents (15%) were the most common. Causality was considered to be definite in 32%, highly likely in 41%, probable in 14%, possible in 10%, and unlikely in 3%. Acute hepatitis C virus (HCV) infection was the final diagnosis in 4 of 9 unlikely cases. Six months after enrollment, 14% of patients had persistent laboratory abnormalities and 8% had died; the cause of death was liver related in 44% Conclusions DILI is caused by a wide array of medications, herbal supplements, and dietary supplements. Antibiotics are the single largest class of agents that cause DILI. Acute HCV infection should be excluded in patients with suspected DILI by HCV RNA testing. The overall 6-month mortality was 8%, but the majority of deaths were not liver related.

In preparation of the paper, there were several errors in the figure labeling, which were regretfully missed in the preparation and proofreading of the manuscript and which the authors would like to correct. None of these changes affects the data or the conclusions of the paper.(1) The heading of Figure 2H should read ''Glucose Infusion Rate,'' not ''Insulin Infusion Rate.'' (2) In the corresponding text on page 431 (right column, paragraph 2, line 13), the units for glucose infusion rate should be ''mg/kg/min,'' not ''mg/dl.'' (3) Likewise, on the y axis in Figure 2I, the units for glucose should read ''mg/kg/min'' rather than ''mg/dl.'' (4) On the y axis in Figures 3C, 4F, 4G, 4H, and 5D, the parenthetical reference to ''ARNT/Actin'' carried over from previous figures should simply be deleted. The correct specific genes or proteins measured in each panel are already indicated. (5) In Figure 5A, the correct units are ''mM,'' not ''mM/l.