IL-6 and IGF-1 are independent prognostic factors of liver steatosis and non-alcoholic steatohepatitis in morbidly obese patients.

BACKGROUND: Lipid accumulation and other histological liver markers characterize patients with non-alcoholic steatohepatitis (NASH). The identification of non-invasive prognostic factors of liver steatosis and NASH are relevant for the unravelling of the mechanisms of this disease, as well as for the clinical diagnoses of these patients.
METHODS: 36 patients with morbid obesity and 12 healthy subjects were consecutively enrolled in this cross-sectional study to determine the serological parameters associated with the degree of hepatic steatosis and NASH. Clinical, biochemical and histologic variables were examined in blood and liver biopsies by descriptive, univariate and multivariate regression analysis.
RESULTS: The patients were distributed as non-NASH (14), probably-NASH (13) and NASH (9), according to the Non-alcoholic fatty liver disease Activity Score (NAS). The study identified remarkable differences in liver steatosis, and glucose, insulin, IL-6 and IGF-1 concentrations in blood among patients with morbid obesity. IL-6 was correlated with the degree of liver steatosis until the morbidly obese patients fulfil the criteria of NASH. The patients with NASH reduced IL-6 concentration in blood. IGF-1 decreased throughout the progression of NASH. TNF-alpha concentration was not related to liver steatosis or NASH in morbidly obese patients. The multivariate regression analysis identified glucose >110 mg/dL, IL-6 >4.81 pg/mL and IGF-1 <130 ng/mL, and homeostasis model assessment (HOMA) >4.5 and IGF-1 <110 ng/mL as independent predictors of hepatic steatosis and NASH, respectively.
CONCLUSIONS: The concentration of glucose, insulin, IL-6 and IGF-1 in blood are useful markers for the selection of patients with liver steatosis or NASH.