PPARGC1A and Hepatic fibrosis: The expression of both PPARGC1A and HAMP was also significantly lower in fast-progressor NAFLD patients, while it was not negatively correlated with fibrosis progression from F1 to F4, suggesting that reductions in PPARGC1A and HAMP expression are not early events in fibrogenesis but important events in progression to advanced liver fibrosis stages.