Inflammatory state of periaortic adipose tissue in mice under obesogenic dietary regimens

High-fat diet or high-sugar diet causes obesity and a chronic low-grade inflammation that leads to the development of diabetes and cardiovascular diseases. Inflammation of the surrounding fat of thoracic aorta namely periaortic adipose tissue (PAAT) has been associated with increased prevalence of vascular diseases in obesity. C57Bl/6 male mice (12 weeks of age) fed a whole grain-based commercial diet (WGD), refined carbohydrate diet (RCD), refined carbohydrate diet plus sweetened condensed milk ad libitum (RCD + CM) or high-fat diet (HFD) for eight weeks were studied. Serum fatty acid (FA) composition was evaluated by gas chromatography. The cellularity (as indicated by DNA and protein contents) and the inflammatory state (as indicated by the contents of TNF-α, IL-6, IL-1β, IL-10, VCAM-1, ICAM-1, leptin and adiponectin measured by ELISA) of the PAAT and thoracic aorta (TA) were evaluated. Both obesogenic regimens (RCD + CM and HFD) increased the content of total fatty acids (FA) in serum and the cellularity of the PAAT compared to WGD. RCD + CM increased serum monounsaturated fatty acid (MUFA) levels and HFD increased serum saturated fatty acid (SFA) levels compared to WGD. RCD (one of the diets used as control) and RCD + CM increased the levels of TNF-α, IL-1β, IL-10 and VCAM-1 in the PAAT compared to WGD. Mice fed with HFD showed decreased contents of TNF-α, VCAM-1 and IL-10 in the PAAT compared to animals fed RCD. The RCD raised the levels of SFA in serum, cellularity and inflammatory state in the PAAT compared to WGD. In conclusion, the effects of obesogenic dietary regimens on PAAT can be interpreted differently when the results are compared with WGD or RCD. We found marked changes in the PAAT and no significant modifications in TA indicating this adipose tissue as the major starting point of vascular diseases.