Beneficial Effect of Amiloride on Progression of Chronic Kidney Disease

This is a randomized, placebo-controlled, double-blinded crossover trial testing the effects of amiloride in patients with chronic kidney disease (CKD) and proteinuria. In CKD with proteinuria, there is aberrant filtration of serine proteases and complement precursors into the tubular lumen. The interaction of these factors leads to proinflammatory complement activation, which may promote inflammation, opsonization, and formation of the membrane-attack complex, causing cell injury. With the aim of preserving kidney function, reducing cardiovascular morbidity, and delaying renal replacement therapy in CKD, this study tests whether amiloride (10 mg/day) protects the filtration barrier, lowers albuminuria, and mitigates kidney inflammation through urokinase inhibition, independent of blood pressure effects. Participants are randomized to receive amiloride (10 mg/day) or placebo for one week, with a 2-3-week washout period in between. Blood and urine samples are collected before and after each treatment period. Additionally, ECG, body composition measurements, blood pressure, and body weight are monitored. The primary outcome measures are urinary C3a, soluble C5-9 (sTCC/MAC), and kidney injury biomarkers KIM-1 and NGAL. Secondary endpoints include the urinary albumin/creatinine ratio, protein/creatinine ratio, and blood pressure.