Effect of pentoxifylline on proteinuria, markers of tubular injury and oxidative stress in non-diabetic patients with chronic kidney disease - placebo controlled, randomized, cross-over study

Background: Inhibition of the renin-angiotensin-aldosterone system (RAAS) with angiotensin converting enzyme inhibitors (ACEI) and/or angiotensin II subtype 1 receptor antagonists (ARB) is a common strategy used in the management of patients with chronic kidney disease (CKD). However, there is no universal therapy that can stop progression of CKD. Pentoxifylline (PTE) is a non-specific phosphodiesterase inhibitor with anti-inflammatory properties. It has been reported to have promising effects in CKD treatment. Methods: In a placebo-controlled, randomized, cross-over study we evaluated the influence of PTE (1200 mg/day) added to RAAS blockade on proteinuria, surrogate markers of tubular injury and oxidative stress-dependent products in 22 non-diabetic patients with proteinuria (0.4-4.3 g per 24h) with normal or declined kidney function [eGFR 37-178 mL/min]. In an eight-week run-in period, therapy using ACEI and/or ARB was adjusted to achieve a blood pressure below 130/80 mm Hg. Next, patients were randomly assigned to one of two treatment sequences: PTE/washout/placebo or placebo/washout/PTE. Clinical evaluation and laboratory tests were performed at the randomization point and after each period of the study. Results: The PTE therapy reduced proteinuria (by 26%) as compared to placebo. There were no differences in α1-microglobulin, urine excretion of N-acetyl-β-d-glucosaminidase (NAG), hsCRP, the urinary excretion of 15-F2t-isoprostane, blood pressure (BP), eGFR and serum creatinine between the PTE and placebo groups. Conclusion: Pentoxifylline may decrease proteinuria in non-diabetic patients with CKD.