Association of dietary fat intake with TLR2 and Myd88 genes expression in prepheral blood mononuclear cells(PBMCs) and serum level of interlukin 1β in patients with metabolic syndrome: a case-control study

Abstract

Background: Metabolic syndrome (MetS) is a worldwide medical condition that is associated with a range of metabolic disorders including glucose intolerance, abdominal obesity, dyslipidemia, and hypertension. It is also considered a proinflammatory condition at the molecular level due to the involvement of adipose tissue and peripheral blood mononuclear cells (PBMCs). Toll-like receptors (TLRs) are membrane receptors that have a potential role in pathogen recognition and intrinsic immune response by activating various inflammatory pathways. After recognizing the target ligands, TLR2 activates cytoplasmic adapter proteins such as Myeloid differentiation 88 (Myd88) which ultimately results in the production of inflammatory cytokines such as IL1β. Regarding the significant roles of diet in MetS as well as overexpression of TLR2 and its signalling adaptor proteins in the development of obesity and inflammation, the present case-control study was aimed to investigate the association of the expression levels of TLR2 and Myd88 in PBMCs with dietary fat intake as well as serum levels of IL1β in patients with Mets, compared to apparently healthy subjects. Materials and Methods: In this age- and gender-matched case-control study, 70 abdominally obese subjects with waist circumference (WC) ≥95cm (34 patients with MetS and 36 controls) were recruited. A checklist was used to collect demographic data, physical activity, and a 3-day record of dietary intake. Five mL blood was collected to measure serum levels of metabolic parameters and IL1β. Those with 3 or more metabolic disorders were defined as MetS, while those having 2 or less were classified as apparently healthy subjects. Furthermore, mRNA was isolated from PBMCs and real time-PCR was performed for TLR2 as well as Myd88 genes expression assay. SPSS version 17 was used for data analysis. Odds ratios with 95% confidence intervals were also reported, using adjusted logistic regression test. Results: There was significant difference in fasting blood sugar (p=0.122), triglyceride (p<0.001), and HDL-C (p=0.005) between the two groups. There was no significant difference in the expression level of TLR2 and myd88 between two groups; however, there was a significant correlation between two genes in the case group (r=0.40, p=0.001). No significant difference was observed in serum level of IL1β and dietary fat intake between the two groups. Also, there was no significant correlation between TLR2 and Myd88 genes expression level as well as serum IL1β and dietary fat intake. Conclusion: There was no significant difference in the expression level of TLR2 and Myd88 as well as dietary fat intake and serum IL1β between the two groups. It seems that WC is a chief mediator of the association of TLR2 and Myd88 as well as serum IL1β with metabolic state.