Adipose tissue remodelling in obese subjects is a determinant of presence and severity of fatty liver disease

Aims: Experimental data suggest that visceral adipose tissue (VAT) dysfunction contributes to non-alcoholic fatty liver disease (NAFLD) development in obesity, however, data on humans are limited. Aims of this study were to investigate the relationship between NAFLD and VAT morphofunctional impairment and to determine whether the extent of VAT remodelling is associated with liver damage and metabolic alterations in obesity. Methods: We analysed data from 40 obese individuals candidate to bariatric surgery in whom paired intraoperative liver and omental biopsies were performed for diagnosing NAFLD and VAT inflammation by immunohistochemistry and mRNA expression studies. Results: Within our study population, NAFLD was significantly associated with greater VAT CD68+macrophages infiltration (P =.04), fibrosis (P =.04) and impaired microvascular density (P =.03) as well as increased expression of markers of local hypoxia, apoptosis and inflammation (UNC5B, CASP7, HIF1-α, IL-8, MIP2, WISP-1, all P <.01). The degree of VAT inflammation correlated with the severity of hepatic injury (steatosis, inflammation, fibrosis; all P <.01) and impaired gluco-metabolic profile. Conclusions: In obese patients, NAFLD is associated in a dose-dependent manner with signs of VAT remodelling, which reflect more severe clinical metabolic impairment. Our study depicts morphological alterations and novel mediators of VAT dysfunction, adding knowledge for future therapeutic approaches to NAFLD and its metabolic complications.