Endocrine Abstracts

Introduction: Obesity is characterized by a low-grade inflammatory state which has been directly related to the development of insulin resistance and diabetes. Circulating lipopolysaccharides (LPS) have been proposed as a triggering factor for this inflammation. Likewise, adipose tissue (AT) capacity for lipid handling and storage is also a key factor for the development of obesity-related metabolic disorders. Animal studies have shown that LPS are able to modify the expression of key factors for AT function. Thus, the aim of this study was to analyze the gene expression of key factors for AT function and inflammation in AT from morbidly obese (MO) patients according to their LPS levels.

Methods: Visceral and subcutaneous AT (VAT and SAT) samples were obtained during bariatric surgery from 70 MO patients to measure mRNA levels. Plasma LPS levels as well as biochemical and anthropometric variables were measured. Patients were classified according to their LPS levels (high LPS levels, H-LPS group and low-LPS levels, L-LPS group). Gene expression was also analyzed after in vitro stimulation with LPS of AT explants from MO patients.

Results: H-LPS group showed higher mRNA levels of inflammatory genes (TLR2, CSF3 and IL6 in VAT; TLR2, MCP1, CSF3 and CD14 in SAT) than L-LPS group. By contrast, H-LPS group had lower mRNA levels of factors related to AT function (FABP4, SREBP1, FASN and Leptin in VAT and FABP4 in SAT). In vitro stimulation with LPS led to an increase in gene expression of inflammatory markers (TLR2, IL6, CSF3 and MCP1) and a decrease in the gene expression of factors related to AT function (PPARγ, SREBP1, FASN, FABP4, SCD and leptin) in VAT.

Conclusions: Circulating LPS can influence AT physiology in morbidly obese patients by decreasing the gene expression of key factors for AT function and by increasing the gene expression of inflammatory markers.