Endocrine Abstracts (2014) 34 P238 | DOI: 10.1530/endoabs.34.P238

Systemic triglycerides as a key determinant of TLR regulated inflammatory risk in human adipose tissue post bariatric surgical intervention and weight loss

Warunee Kumsaiyai1, Nasser Al-Daghri2, Ioannis Kyrou1, Jana Vrbikova3, Vojtech Hainer3, Martin Fried3, Petra Sramkova4, Thomas Barber1,5, Sudhesh Kumar1, Gyanendra Tripathi1 & Philip McTernan1


1Division of Metabolic and Vascular Health, Clinical Sciences Research Laboratories, Warwick Medical School, Coventry, UK; 2Biomarkers Research Program, Biochemistry Department, College of Science, King Saud University, Riyadh, Saudi Arabia; 3Institute of Endocrinology, Prague, Czech Republic; 4OB Clinic, Prague, Czech Republic; 5Human Metabolism Research Unit, WISDEM, UHCW, Coventry, UK.


Background and aims: Bariatric surgery can lead to a quick reversal in type 2 diabetes mellitus (T2DM) status. However, despite this reversal inflammatory responses may still persist via activation of Toll-like receptors (TLR) within adipose tissue (AT); with triglycerides (TGs) noted as a potential mediator of such inflammation. Therefore the aims of these studies were to understand the impact of TG changes, pre- and post-bariatric surgery, on TLR expression in ex vivo AT and the in vitro effects of triglyceride rich lipoprotein (VLDL), on TLR expression in isolated human differentiated pre-adipocytes.

Materials and methods: Obese, T2DM, female subjects (age: 54.6±6.6 years, BMI pre (41.2±5.5 kg/m2) and 6 months post-surgery (36.05±5.16 kg/m2; n=30) underwent bariatric surgery (banding (n=8); plication (n=14); and biliopancreatic diversion (n=8)). Biochemical data and abdominal subcutaneous AT (AbdSc AT) samples were taken during surgery and 6 months post-surgery. Real-time PCR assessed TLR expression. Human differentiated pre-adipocyte Chub S7 cells were used to examine transcriptional effects of VLDL on TLR expression.

Results: Following surgical intervention, BMI (P<0.001), blood glucose (P<0.001), insulin (P<0.001), HOMA-IR (P<0.001), TG (P<0.05), cholesterol (P<0.001), and LDL-cholesterol (P<0.05) were significantly improved. There was a significant reduction in TLR4 mRNA post-surgery (P<0.01) irrespective of surgery type. It was also noted that subjects with the greatest drop (55.5% reduction) in TGs post-surgery (P<0.001) showed a significant correlated reduction in TLR4 mRNA expression (P<0.001). In vitro treatment of differentiated Chub S7 cells highlighted VLDL induced TLR4 mRNA expression (P<0.05).

Conclusion: There is a reduction in AT inflammation as denoted by TLR expression. The reduction in AT inflammation appears dependent on how successfully subjects reduce their serum triglyceride, which is supported by in vitro studies. These studies suggest that bariatric surgery lead to metabolic improvement with weight loss, whilst dietary intervention is still required to ensure TGs reduce to reduce inflammation.