The Role of Cardio-Renal Inflammation in Deciding the Fate of the Arteriovenous Fistula in Haemodialysis Therapy

Vascular access is an indispensable component of haemodialysis therapy for end-stage kidney disease patients. The arteriovenous fistula (AVF) is most common, but importantly, two-year failure rates are greater than fifty percent. AVF failure can occur due to a lack of suitable vascular remodelling, and inappropriate inflammation preventing maturation, or alternatively neointimal hyperplasia and vascular stenosis preventing long-term use. A comprehensive mechanistic understanding of these processes is still lacking, but recent studies highlight an essential role for inflammation from uraemia and the AVF itself. Inflammation affects each cell in the cascade of AVF failure, the endothelium, the infiltrating immune cells, and the vascular smooth muscle cells. This review examines the role of inflammation in each cell step by step and the influence on AVF failure. Inflammation resulting in AVF failure occurs initially via changes in endothelial cell activation, permeability, and vasoprotective chemokine secretion. Resultingly, immune cells can extravasate into the subendothelial space to release inflammatory cytokines and cause other deleterious changes to the microenvironment. Finally, all these changes modify vascular smooth muscle cell function, resulting in excessive and unchecked hyperplasia and proliferation, eventually leading to stenosis and the failure of the AVF. Finally, the emerging therapeutic options based off these findings are discussed, including mesenchymal stem cells, small-molecule inhibitors, and far-infrared therapies. Recent years have clearly demonstrated a vital role for inflammation in deciding the fate of the AVF, and future works must be centred on this to develop therapies for a hitherto unacceptably underserved patient population.