The Evolving Role of Leptin and Adiponectin in Chronic Liver Diseases

Abstract

Leptin and adiponectin, the main metabolic products of adipose tissue, have been implicated in a wide spectrum of human diseases. Given the frequent presence of hepatic steatosis in several chronic liver diseases, there is currently increasing interest in the role of these adipokines in the development of hepatic steatosis and also in necroinflammation and fibrosis, mostly in patients with nonalcoholic fatty liver disease or chronic hepatitis C. According to experimental data, reduced adiponectin levels and increased leptin levels associated with leptin resistance, which are usually observed in obese patients with or without metabolic syndrome, may result in fat accumulation in the liver and in the enhancement of liver inflammation and mostly fibrogenesis. Increased leptin and decreased adiponectin serum levels have been detected initially in patients with nonalcoholic steatohepatitis and more recently in patients with chronic hepatitis C compared to healthy controls in most but not all studies, while the data on the associations between these adipokine levels and the severity of hepatic steatosis or fibrosis are still rather conflicting. However, several potential confounding parameters were not evaluated in all studies. Therefore, the associations between adipokines and liver histological lesions and their effects on liver cells should be evaluated further in prospective, carefully designed studies, including larger cohorts of patients with detailed assessment of metabolic and other potential confounding factors.

Probable NAFLD, by ALT levels, and diabetes among Filipino-American Women

“…Existing studies suggest hypoadiponectinemia in NAFLD enhances insulin resistance by decreasing hepatic insulin sensitivity [41] and increasing production of the inflammatory protein, tumor necrosis factor-α [42]. Hypoadiponectinemia may perpetuate hepatic fat accumulation through an influx of free fatty acids into the liver resulting in hepatic steatosis [42,43]. Japanese women with NAFLD, defined by ultrasound, and mean ALT level of 45 U/L had significantly lower adiponectin concentration compared to those without NAFLD (7.2 vs. 9.0 ug/mL, p <0.005) [26].…”

Current role of fenofibrate in the prevention and management of non-alcoholic fatty liver disease

“…Patients with MetS and/or T2DM have low circulating adiponectin levels [86,87] . These are also decreased in patients with NAFLD, possibly due to enhanced hepatic insulin resistance together with declined FA β-oxidation [88,89] . In contrast, recombinant adiponectin administration exerted protective effects against NAFLD in mice [90] .…”

Adipocytokine Imbalance and Ghrelin in the Development of Insulin Resistance in Patients with Chronic Hepatitis C

“…A higher value of leptin according to E Tsochatzis can enhance IR, increase the cellular pool of fatty acids, and lead to the formation of liver steatosis [31]. B.Mattioli demonstrated that leptin may enhance the production of proinflammatory cytokines, including TNF-α [32].…”