The Inflammation Spectrum of Monocytes in Relation to Obesity and Severity of Type 2 Diabetes (T2D), A Case-Control Study

Introduction. Increased monocyte and macrophage inflammatory state and pro-inflammatory cytokine production are linked to type 2 diabetes (T2D). Research design and Methods. This is a case-control study aimed to examine the expression of 23 monocyte genes related to inflammation, adhesion, and repair in individuals with mild (mean HbA1c 7.3%, illness duration 5.6 years) and severe type 2 diabetes (mean HbA1c 8.4%, disease duration 14.2 years) compared also with lean and obese controls. In addition, we determined a set of serum inflammatory cytokines and growth factors. Results. The monocytes of mild T2D patients (who were in general overweight/obese) showed overexpression of a subset of genes related to adhesion (CD9), vascular repair and growth (HGF). The monocytes of the severe T2D patients showed in contrast an upregulation of many of the pro-inflammatory genes, without a significantly increased expression of the repair gene HGF and the adhesion gene CD9. Serum cytokine expression in the severe T2D patients supported the increased inflammatory state of the patients showing high levels of IL-6, IL-1β, and TNF-α. Conclusions. This study, therefore, shows a pro-inflammatory gene expression profile of monocytes of severe T2D patients, while patients with mild T2D did not show such monocyte profile.