Absence of receptor interacting protein kinase 3 prevents ethanol-induced liver injury.

UNLABELLED: Hepatocyte cell death via apoptosis and necrosis are major hallmarks of ethanol-induced liver injury. However, inhibition of apoptosis is not sufficient to prevent ethanol-induced hepatocyte injury or inflammation. Because receptor-interacting protein kinase (RIP) 3-mediated necroptosis, a nonapoptotic cell death pathway, is implicated in a variety of pathological conditions, we tested the hypothesis that ethanol-induced liver injury is RIP3-dependent and RIP1-independent. Increased expression of RIP3 was detected in livers of mice after chronic ethanol feeding, as well as in liver biopsies from patients with alcoholic liver disease. Chronic ethanol feeding failed to induce RIP3 in the livers of cytochrome P450 2E1 (CYP2E1)-deficient mice, indicating CYP2E1-mediated ethanol metabolism is critical for RIP3 expression in response to ethanol feeding. Mice lacking RIP3 were protected from ethanol-induced steatosis, hepatocyte injury, and expression of proinflammatory cytokines. In contrast, RIP1 expression in mouse liver remained unchanged following ethanol feeding, and inhibition of RIP1 kinase by necrostatin-1 did not attenuate ethanol-induced hepatocyte injury. Ethanol-induced apoptosis, assessed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling-positive nuclei and accumulation of cytokeratin-18 fragments in the liver, was independent of RIP3. CONCLUSION: CYP2E1-dependent RIP3 expression induces hepatocyte necroptosis during ethanol feeding. Ethanol-induced hepatocyte injury is RIP3-dependent, but independent of RIP1 kinase activity; intervention of this pathway could be targeted as a potential therapeutic strategy.

Macrophage migration inhibitory factor contributes to ethanol-induced liver injury by mediating cell injury, steatohepatitis, and steatosis.

UNLABELLED: Macrophage migration inhibitory factor (MIF), a multipotent protein that exhibits both cytokine and chemotactic properties, is expressed by many cell types, including hepatocytes and nonparenchymal cells. We hypothesized that MIF is a key contributor to liver injury after ethanol exposure. Female C57BL/6 or MIF-/- mice were fed an ethanol-containing liquid diet or pair-fed control diet for 4 (11% total kcal;early response) or 25 (32% kcal; chronic response) days. Expression of MIF messenger RNA (mRNA) was induced at both 4 days and 25 days of ethanol feeding. After chronic ethanol, hepatic triglycerides and plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were increased in wildtype, but not MIF-/-, mice. In order to understand the role of MIF in chronic ethanol-induced liver injury, we investigated the early response of wildtype and MIF-/- to ethanol. Ethanol feeding for 4 days increased apoptosis of hepatic macrophages and activated complement in both wildtype and MIF-/- mice. However, tumor necrosis factor alpha (TNF-α) expression was increased only in wildtype mice. This attenuation of TNF-α expression was associated with fewer F4/80+ macrophages in liver of MIF-/- mice. After 25 days of ethanol feeding, chemokine expression was increased in wildtype mice, but not MIF-/- mice. Again, this protection was associated with decreased F4/80+ cells in MIF-/- mice after ethanol feeding. Chronic ethanol feeding also sensitized wildtype, but not MIF-/-, mice to lipopolysaccharide, increasing chemokine expression and monocyte recruitment into the liver. CONCLUSION: Taken together, these data indicate that MIF is an important mediator in the regulation of chemokine production and immune cell infiltration in the liver during ethanol feeding and promotes ethanol-induced steatosis and hepatocyte damage.

Effect of Acid-Suppressive Strategies on Pazopanib Efficacy in Patients With Soft-Tissue Sarcoma.

Pazopanib (PAZ), a tyrosine kinase inhibitor used in the treatment of soft tissue sarcoma (STS), should not be administered with acid-suppressive medications (ASMs) due to decreased drug solubility. Common practice for patients requiring ASM with PAZ is to separate administration by 12 hours; however, there is little real-world evidence describing clinical outcomes using this strategy. The aim of this study was to determine whether concomitant ASM impacted efficacy and adverse event rates in patients with STS receiving PAZ. Medical records were retrospectively reviewed for patients with STS who received PAZ from June 2011 to July 2017. Patients were stratified into two groups, PAZ with or without ASM (PAZ + ASM or PAZ only). The primary objective was to determine whether progression-free survival (PFS) differed between groups. Secondary objectives were to determine overall survival (OS) and occurrence of grade 3/4 toxicities. Ninety-one patients were included in the study, 42 patients in the PAZ + ASM group and 49 in the PAZ only group. Median PFS was significantly shorter in the PAZ + ASM group than the PAZ only group (5.3 vs. 6.7 months). The PAZ + ASM group also had a 74% higher relative risk of progression or death than the PAZ only group, but there was no difference in OS. Regarding adverse events, the PAZ + ASM group trended toward lower levels of grade 3/4 hypertension (19% vs. 37%). These results suggest that ASM should be avoided in patients with STS receiving PAZ. Larger studies are needed to further elucidate the impact of ASM use with PAZ in clinical practice.