Adipokines and proinflammatory cytokines, the key mediators in the pathogenesis of nonalcoholic fatty liver disease
摘要
Nonalcoholic fatty liver disease(NAFLD)is a condition in which excess fat accumulates in the liver of a patient with no history of alcohol abuse or other causes for secondary hepatic steatosis.The pathogenesis of NAFLD and nonalcoholic steatohepatitis(NASH)has not been fully elucidated.The'two-hit'hypothesis is probably a too simplified model to elaborate complex pathogenetic events occurring in patients with NASH.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.Adipose tissue,which has emerged as anendocrine organ with a key role in energy homeostasis,is responsive to both central and peripheral metabolic signals and is itself capable of secreting a number of proteins.These adipocyte-specific or enriched proteins,termed adipokines,have been shown to have a variety of local,peripheral,and central effects.In the current review,we explore the role of adipocytokines and proinflammatory cytokines in the 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-α,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.