The role of leptin and adiponectin in chronic liver diseases

Abstract

Adipose tissue is currently considered to be a metabolically
active organ that secretes hormones which regulate energy
balance. Leptin and adiponectin are its main metabolic
products and have been implicated in a wide spectrum of
human diseases including liver diseases. These two hormones
have been initially studied in non-alcoholic fatty liver
disease, which is considered to be part of the metabolic syndrome.
Leptin seems to have fibrogenic potential and serum
leptin levels have been found to be higher in patients
with non-alcoholic steatohepatitis (NASH) than in controls.
On the other hand, serum adiponectin levels have been
found to be inversely related to the presence of NASH. As
steatosis is a common histopathological finding of chronic
hepatitis C, serum leptin and adiponectin levels were measured
in such patients and found to be significantly higher
and lower compared to healthy controls, respectively. However,
it is not yet clear whether they are just markers of
liver steatosis and fibrosis or whether they have a direct
pathogenic or protective role. Therefore, the associations
between leptin-adiponectin and liver steatosis and/or fibrosis
should be evaluated further in prospectively designed
studies including larger cohorts of NASH and chronic hepatitis
C patients with detailed assessment of metabolic and
several potential confounding factors. Moreover, their
measurement in other liver diseases, which are considered
to be infrequently associated with steatosis, such as chronic
hepatitis B, would clarify if their action is mediated by
or is independent of steatosis.