Conclusion: Deficiency

of MCP-1 protects mice against alcoholic liver injury, independent of CCR2, by inhibition of proinflammatory cytokines and induction of genes related to fatty acid oxidation, linking chemokines to hepatic lipid metabolism. (HEPATOLOGY 2011) Alcoholic liver disease (ALD) is a major health concern, and approximately 90% of heavy drinkers develop fatty liver disease or steatosis. KU-60019 molecular weight Fatty liver is occasionally accompanied by, or progresses to, inflammation in human ALD. The essential role of innate immune cell activation and circulating endotoxin/lipopolysaccharide (LPS) in ALD has been proposed.1, 2 Circulating endotoxin activates liver macrophages and leads to the induction of cytokines, chemokines, and reactive oxygen species.3 Though proinflammatory

cytokine production in the alcoholic liver is extensively investigated, the importance of chemokines is still unknown. Elevation of chemokines, such as interleukin (IL)-8, monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein 1 (MIP-1), in alcoholic hepatitis and cirrhotic patients and the correlation with the recruitment of polymorphonuclear leukocytes is reported.4, 5 However, the pathophysiological mechanisms affected by chemokines in ALD are yet to be determined. CC-chemokines induce the recruitment and activation of mononuclear cells, such as monocytes/macrophages, T cells and natural killer T cells,6, 7 and these cells play an important role in the development EPZ-6438 price and propagation of alcoholic liver injury.8 MCP-1 or chemokine (C-C motif) ligand 2 (CCL2), an important CC-chemokine, recruits and activates monocytes/macrophages to the site of tissue injury and regulates adhesion molecules and proinflammatory cytokines tumor necrosis factor alpha (TNFα), IL-1β, and IL-6.9, 10 The pivotal role of MCP-1 in alcoholic liver injury was first recognized by studies showing higher amounts of MCP-1, as SDHB compared to other CC-chemokines, such as MIP-1α and MIP-1β, in the liver and mononuclear cells of patients with alcoholic hepatitis.4, 5 Subsequently, the pathogenic role of MCP-1 expressed by liver macrophages and endothelial cells was demonstrated in rodent models of

alcoholic hepatitis.11 Besides macrophage activation, MCP-1 appears to play a significant role in hepatic steatosis or early liver injury. Recently, transgenic mice overexpressing MCP-1 in adipose tissue exhibited insulin resistance and increased hepatic triglyceride content.12 These studies were based on the observations that mice fed a high-fat diet led to MCP-1 induction in adipose tissue, but not liver.12In vitro studies also demonstrated that MCP-1 can induce lipid accumulation in hepatocyte cultures.13 In general, MCP-1 seems to play an important role in hepatic inflammatory responses and steatosis during tissue injury. Previous studies from our laboratory and others have shown the pathophysiological importance of proinflammatory cytokines in ALD.