Factors associated with serum soluble inhibitors of Wnt--catenin signaling (sclerostin and dickkopf-1) in patients undergoing peritoneal dialysis

AimSclerostin and dickkopf-1 (Dkk-1) are soluble inhibitors of Wnt--catenin signaling and are involved in decreased bone formation and bone volume in patients with various bone diseases. The clinical characteristics of sclerostin and Dkk-1 and their impacts on mineral and bone metabolism remain undetermined in patients undergoing peritoneal dialysis (PD). MethodsThis cross-sectional study investigated the association between serum sclerostin and Dkk-1 levels and mineral disorders in 74 outpatients under PD treatment. Levels of sclerostin and Dkk-1 in serum, urine, and peritoneal dialysate were determined using enzyme-linked immunosorbent assay kits. The associations between serum sclerostin and Dkk-1 levels and biochemical parameters were evaluated by linear regression analyses. ResultsMedian serum sclerostin and Dkk-1 levels were 138pmol/L (range, 98.3-195.9pmol/L) and 38.8pmol/L (range, 28.5-47.1pmol/L), respectively. Both sclerostin and Dkk-1 were excreted into urine and peritoneal dialysate. Multivariable linear regression analyses showed that serum sclerostin level was significantly associated with age, sex, parathyroid hormone level, and renal Kt/V. In contrast, serum Dkk-1 level was associated with platelet count and serum fibroblast growth factor 23 level but not with any of the bone metabolic markers. ConclusionSerum sclerostin was associated with serum intact parathyroid hormone, while Dkk-1 was associated with serum fibroblast growth factor 23 in patients undergoing PD. The utility of determining soluble Wnt--catenin inhibitors levels in patients undergoing PD requires further investigation. Summary at a Glance This cross-sectional study investigates the metabolism and association between serum sclerostin and Dkk-1 levels and serum mineral markers in 74 outpatients under PD treatment. Multivariable linear regression analyses show that both serum sclerostin and Dkk-1 level were significantly associated with the serum biomarkers of CKD-MBD, indicating the involvement of soluble Wnt--catenin inhibitors in the pathogenesis of CKD-MBD.