Chronic low-grade inflammatory condition is associated with metabolic pathologies such as obesity. However, the role exerted by local inflammation occurring in different fat depots, such as subcutaneous (SAT) versus visceral (VAT) adipose tissue (AT), is still under evaluation. Aim of the present study was to characterize the inflammatory state in adipose tissue of obese (OB: n=58, mean±S.D. BMI=47±9) vs normoweight (NOR: n=28, mean±S.D BMI=24±2) patients subjected to bariatric or general abdominal surgery at our University Hospital.
Blood, VAT and SAT biopsies were collected at surgery for analyses. Cytofluorimetric immunophenotyping of blood cells and stromal vascular fraction obtained from AT revealed a higher presence of gammadelta lymphocytes in blood and AT from OB vs NOR. Moreover, TaqMan analysis of gene expression confirmed a significant increase in specific inflammatory markers in AT of OB (n=38) vs NOR (n=26), being VAT from OB interested by a significantly worse inflammatory state characterized by M1 macrophage polarization (CD40+SE expression fold increase=3.76+0.68 in VAT of OB/NOR, P<0.005; CD206+SE expression fold increase=0.39+0.04 in VAT of OB/NOR, P<0.05) and decreased regulatory components (IL10 VAT/ SAT±SE expression=10.6±3.9 in NOR and 1.6±0.4 in OB, P<0.05; foxp3/CD3±SE expression: 27.7±12.3 SAT and 5.5+1.5 VAT of NOR, 17.4+1.8 SAT and 3.2+0.5 VAT of OB; P<0.05 VAT NOR vs OB and P<0.001 OB SAT vs VAT). This condition was associated with a reduced VAT functionality in OB vs NOR evaluated by adiponectin expression (adiponectin±SE expression: 29.1E6±10.1E6 SAT and 18.0E6±.9E6 VAT in 17 NOR, 10.2E6±1.7E6 SAT and 6.5E6±1.1E6 VAT in 26 OB; P<0.01 SAT and VAT NOR vs OB, P<0.05 OB SAT vs VAT).
In conclusion, these data suggest that obese AT is characterized by a local inflammation associated with functional metabolic alterations, more evident in VAT than SAT, which may play a pivotal role in the development of metabolic pathologies.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This work was supported, however funding details unavailable.
05 - 09 May 2012
European Society of Endocrinology