Immunomodulation Effect of Regional Citrate Anticoagulation in Acute Kidney Injury Requiring Renal Replacement Therapy

Introduction: Acute kidney injury (AKI) is a common syndrome in critically ill patients. Continuous renal replacement therapy (CRRT) is the standard treatment for patients with AKI. Research on the immunomodulating effects of regional citrate anticoagulation (RCA) remains limited in patients with AKI receiving CRRT. We aimed to evaluate the immunomodulating effects of RCA in patients with AKI receiving CRRT. Methods: A randomized controlled trial study on critically ill adult patients with AKI undergoing CRRT was undertaken. Participants were randomized into either a regional citrate group or control group (either heparin anticoagulant or normal saline). Measurements were taken at baseline, 6 and 24 h after commencing CRRT for CD11b expression, C3a, C5a, and plasminogen activator inhibitor-1 (PAI-1) levels. Clinical outcomes assessed were 28-day survival rate, length of ICU stay, renal support duration, and renal function at discharge. Results: Thirty patients were recruited and randomized into 2 groups of 15 subjects. Baseline demographic and clinical data were comparable between groups. In the citrate group, CD11b expression was significantly decreased at 24 h compared to the control group (1.84% [1.18-3.32] versus 4.92% [2.63-6.93], p < 0.01). The complement level, including c3b and c5a, was stable during CRRT. Additionally, the PAI-1 levels were significantly decreased at 24 h compared to the control group (114 ng/mL [19-193] versus 359 ng/mL [264-491], p < 0.01). No significant difference in survival rate was observed. Conclusions: RCA may have the potential to mitigate the inflammatory response by decreasing CD11b expression of neutrophil and improve fibrinolysis activity through a reduction of PAI-1 levels. Larger clinical trials are warranted to test this immunomodulation effect of RCA.