Peritoneal and renal DKK3 clearance in peritoneal dialysis.

Background: Urinary Dickkopf 3 (DKK3) excretion is a recently established biomarker of renal functional development. Its excretion into the peritoneal cavity has not been reported. We here studied DKK3 in peritoneal dialysis. Methods: DKK3 was assessed in serum, urine and dialysate in a prevalent adult peritoneal dialysis cohort and its concentration analyzed in relation to creatinine and clinical characteristics. Results: Highest DKK3 concentrations were found in serum, followed by urine. Dialysate concentrations were significantly lower. Dialysate DKK3 correlated with both other compartments. Serum, dialysate and urine values were stable during three months of follow-up. Continuous ambulatory dialysis (CAPD) but not cycler-assisted peritoneal dialysis (CCPD) volume-dependently increased peritoneal DKK3 in relation to creatinine. RAAS blockade significantly decreased urinary, but not serum or peritoneal DKK3. Conclusion: Our data provide a detailed characterization of DKK3 in peritoneal dialysis. They support the notion that the RAAS system is essential for renal DKK3 handling. [ABSTRACT FROM AUTHOR]