NETosis before and after hyperglycemic control in type 2 diabetes mellitus patients

Abstract

Introduction and Objective: Diabetes is characterized by chronic inflammation, endothelial dysfunction, increased risk of infections and early cardiovascular disease. By releasing neutrophil extracellular traps (NETs), neutrophils kill bacteria and exert pro-inflammatory and pro-thrombotic activities. Increased NETosis has been found in cross-sectional studies including treated type 2 diabetes mellitus (T2DM) patients. In this study, we determined whether the ability of neutrophils to form NETs differs in diabetic patients pre- and post-hyperglycemic control versus healthy donors (HD), and the relationship between NETosis with pro-thrombotic, pro-inflammatory biomarkers and thrombotic clinical events. Methods: Diabetic patients recently diagnosed and after 6 and 12 months of treatment (N = 25) and HD (N = 25) were included. NET formation was studied by microscopy and fluorometry. Nucleosomes, HNE-DNA complexes, von Willebrand factor (vWF), IL6 and TNFα plasma levels were measured by ELISA and P-selectin on the platelet surface was assessed by cytometry. Results: Basal levels of NETs in recently diagnosed T2DM patients were higher compared to HD. While TNFα stimulation of control neutrophils resulted in DNA release, patient neutrophils were not responsive. Although glycemia decreased after 6 months of metformin treatment, basal and TNFα and PMA-stimulated NETs reached normal values after 12 months. Compared to controls, nucleosomes, HNE-DNA complexes, IL-6 and TNFα levels were increased in recently diagnosed patients and decreased after 12 months of treatment. P-selectin and vWF levels were similar in both populations. Conclusion: Our data suggest that NETs could represent a biomarker for T2DM. Increased NETosis in T2DM patients does not appear to be the consequence of impaired glycemic control but rather due to pro-inflammatory cytokines and is not related to thrombotic events.