Endothelial activation and inflammation in chronic kidney disease (CKD): role of neutrophil extracellular traps (NETs)

Advanced chronic kidney disease (CKD), especially in stages 4-5, amplifies cardiovascular disease (CVD) risk by around 50%. This heightened susceptibility is linked to a 1.5 to 3-fold increase in venous thromboembolism incidence, driven by coagulation dysregulation and heightened inflammation. During inflammation, neutrophils can release extracellular traps (NETs), that was described contribute to endothelial damage, through adhesion molecule elevation, and tissue factor (TF) secretion, exacerbating thrombosis. Additionally, NETs interact with von Willebrand Factor (vWF) and factor XII, further amplifying thrombus formation and the activation of the intrinsic coagulation pathway.
This study examined whether NETs may contribute to increased CVD risk in CKD patients by inducing endothelial activation and thromboinflammatory responses to a larger extent compared to NETs from healthy donors. For that, neutrophils were isolated from healthy donors’ and CKD patients’ (stages 3-5) peripheral blood, and NETs were collected by stimulating neutrophils with PMA for 3.5 hours. HAoECs were subsequently exposed to NETs for 3 to 24 hours, followed by gene expression analysis with a focus on inflammation, endothelial activation, and prothrombotic markers. Additionally, protein analysis of the supernatant was conducted using ELISA.
Exposure to both healthy NETs as well as NETs isolated from CKD patients resulted in a notable upregulation of endothelial activation (VCAM-1), prothrombotic (TF), and inflammatory (IL-6) gene expression within 3 hours, without difference between healthy and CKD conditions. On the other hand, when examining the cellular supernatant, a significantly higher increase in vWF secretion was observed upon treatment with CKD-NETs compared to healthy NETs. Furthermore, while secretion of the inflammatory cytokine IL-6 presented a comparable increase upon treatment with NETs derived from healthy and CKD neutrophils, IL-1β secretion was markedly enhanced after CKD-NET treatment in comparison to healthy NETs.
In summary, our findings suggest that NETs exert a significant influence on endothelial cells, contributing to increased thromboinflammatory activation. Notably, CKD-NETs evoked a more rapid impact on the endothelium, accompanied by increased secretion of IL-1β and vWF, and underlying mechanisms will be further investigated.