NETosis-associated serum biomarkers are reduced in type 1 diabetes in association with neutrophil count

Abstract

1These authors contributed equally to this study. SummaryAs the immune pathways involved in the pathogenesis of type 1 diabetes (T1D) are not fully understood, biomarkers implicating novel mechanisms of disease are of great interest and call for independent evaluation. Recently, it was reported that individuals with T1D display dramatic elevations in circulating components of neutrophil extracellular traps (NETs), indicating a potential role for NETosis in T1D. Our aim was to evaluate further the potential of NET-associated proteins as novel circulating biomarkers in T1D. We tested serum from subjects with T1D (n 5 44) with a median age of 26Á5 years and a median duration of 2Á2 years, along with 38 age-matched controls. T1D subjects did not show elevations in either neutrophil elastase (NE) or proteinase 3 (PR3), as reported previously. In fact, both NE and PR3 levels were reduced significantly in T1D subjects, particularly in subjects within 3 years of diagnosis, consistent with the known reduction in neutrophil counts in recent-onset T1D. Indeed, levels of both NE and PR3 correlated with absolute neutrophil counts. Therefore, while not ruling out potential local or transient spikes in NETosis activity, the levels of these serum markers do not support a role for systemically elevated NETosis in the T1D population we studied. Rather, a modest reduction in these markers may reflect other important aspects of disease activity associated with reduced neutrophil numbers.

Increased formation of neutrophil extracellular traps is associated with gut leakage in patients with type 1 but not type 2 diabetes

“…A study in China demonstrated that increased NET formation is closely associated with β‐cell autoimmunity in T1D patients, with similar results found in animal models . In contrast, another study in North America reported that circulating concentrations of NET‐associated biomarkers are reduced in T1D patients . Furthermore, NET‐associated biomarkers are elevated in T2D patients, whereas NET formation has been reported to be impaired and delayed by high‐glucose conditions .…”

NETosis before and after Hyperglycemic Control in Type 2 Diabetes Mellitus Patients

“…In contrast, it has been recently reported that serum levels of elastase and proteinase 3, two proteins present in NETs, are significantly reduced in Type 1 diabetes patients and are correlated with a reduction in neutrophil counts [28]. In our study, neutrophil counts did not differ between control subjects or patients and the amount of nucleosomes/neutrophil in T2DM patients was higher than control subjects, ruling out the idea that the augmented nucleosomes levels observed in T2DM patients were associated with an increased neutrophil number.…”

Quantification of NETs‐associated markers by flow cytometry and serum assays in patients with thrombosis and sepsis

“…The sample was centrifuged for 15 minutes at 1500 g at 4 ° C. For plasma samples, blood was collected in EDTA tube and centrifuged for 15 minutes at 1500 g at 4 ° C. The serum or plasma was carefully aspirated, aliquoted and stored at −80 ° C until measurement. Serum or plasma was frozen within 2 hours of collection as previously described …”