IL-1 and IL-1 were shown to have a role in the transformation of steatosis to steatohepatitis and liver fibrosis[255]. IL-1 is a member of the IL-1 family most commonly investigated in the pathogenesis of NAFLD. pathogenesis of NAFLD. We particularly focus on adiponectin, leptin and ghrelin, with a brief mention of resistin, visfatin and retinol-binding protein 4 among adipokines, and tumor necrosis factor-, interleukin (IL)-6, IL-1, and briefly IL-18 among proinflammatory cytokines. We update their role in NAFLD, as elucidated in experimental models and clinical practice. Keywords:Nonalcoholic fatty liver disease, Cytokines, Adipokines, Adiponectin, Leptin, Tumor necrosis factor-, Interleukin-6, Interleukin-1, Interleukin-18, Ghrelin Core tip:The pathogenesis of nonalcoholic fatty liver disease (NAFLD) is still not fully elucidated. We explored the role of the following adipocytokines and proinflammatory cytokines in the pathogenesis Chicoric acid of NAFLD: adiponectin, leptin, ghrelin, resistin and visfatin among adipokines, and tumor necrosis factor- (TNF-), interleukin (IL)-6 and IL-1 among proinflammatory cytokines. Although a definite conclusion is usually complex, from analyzed data we could conclude that adiponectin, des-acyl ghrelin and leptin are adipokines that decrease, while TNF- and IL-6 are cytokines that enhance insulin resistance and subsequently NAFLD. Acting on these premises, new therapeutic possibilities emerge; however, much work remains to be done. == INTRODUCTION == In nonalcoholic fatty liver disease (NAFLD) excess fat accumulates in the liver of a patient with no history of alcohol abuse or other causes for secondary hepatic steatosis[1]. NAFLD represents a complex spectrum of diseases, and is usually classified into nonalcoholic fatty liver (simple steatosis) and nonalcoholic steatohepatitis (NASH). Simple steatosis is usually characterized by the presence of steatosis without evidence of significant inflammation or fibrosis, while in NASH, steatosis is usually associated with hepatic inflammation that may be histologically indistinguishable from alcoholic steatohepatitis, and is often accompanied by progressive Rabbit Polyclonal to PNPLA8 fibrosis. Long-standing NASH may progress to liver cirrhosis and is probably an important cause of cryptogenic cirrhosis; end-stage liver disease and hepatocellular carcinoma may be possible outcomes[2]. NAFLD is regarded as a hepatic manifestation of metabolic syndrome (MS), and patients with NAFLD, particularly those with NASH, often have one or more components of the MS: obesity, hypertension, dyslipidemia and raised fasting plasma glucose levels or overt type 2 diabetes (T2DM). The epidemiological data for NAFLD vary depending on the populace and region analyzed, but estimated prevalence of NAFLD worldwide is around 20%, with 2%-3% of adults having NASH. It is the most common liver disorder in the Western industrialized countries, where the major risk factors for NAFLD are common. Clinical studies have revealed an increasing prevalence of NAFLD worldwide, and especially worrying data come from studies of children and adolescents where NAFLD is usually on the rise, together with obesity and MS, and such an early onset of the disease may provide more time for its deleterious development through the lifetime. The pathogenesis of NAFLD and NASH is still extensively researched. Although it is sometimes explained by a two-hit hypothesis, it should be better regarded as a multiple step process, with accumulation of liver fat being the first step, followed by the development of necroinflammation and fibrosis[3]. Strong epidemiological, biochemical, and therapeutic evidence implicate insulin resistance (IR) as the primary pathophysiological derangement and the key mechanism leading to hepatic steatosis[4]. Insulin actions are altered in IR and MS, resulting in increased lipolysis and synthesis of free fatty acids (FFA) Chicoric acid and decreased apolipoprotein B-100 in the liver. Accumulation of triglycerides in the liver thus represents the primary insult or the first hit in the pathogenesis of NAFLD, but Chicoric acid the progression of NASH requires the presence of additional pathophysiological abnormalities. The next step or the second hit is the result of reactive oxygen species (ROS) that increase oxidative stress within the hepatocytes, and by that mediate progression from steatosis to steatohepatitis and fibrosis. Also a third hit has been proposed, based on the fact that oxidative stress causes progressive cell death with diminished replication of mature hepatocytes and subsequent increased progenitor cell growth, leading to progression of liver cirrhosis and hepatocellular carcinoma. A number of recent reviews have pointed out the importance of gut microbiota, which is now considered also as a metabolic organ, in the pathogenesis of metabolic and inflammatory diseases such as obesity and T2DM[5-7]. Aron-Wisnewsky et al[8] summarized the influence of gut microbiota in promoting NASH in five actions. Disregulated microbiota promotes energy yield from food, as was observed in animal (obese animals had a.