OPG, RANK-L, bone metabolism, and BMD in patients on peritoneal dialysis and hemodialysis

Objectives Bone turnover is regulated locally by osteoprotegerin (OPG) and receptor activator of NFκB ligand (RANK-L); it is not known how the circulating concentrations of these cytokines reflect renal osteodystrophy. Methods We measured serum OPG, RANK-L, parathyroid hormone (iPTH), collagen C-terminal cross-linked telopeptide (βCrossLaps), and bone densitometry (BMD) in 79 patients with end-stage renal disease (ESRF) undergoing dialysis. A hand X-ray of these patients was also analyzed. Controls were 65 healthy subjects. Results ESRF patients had high OPG and RANK-L levels; RANK-L was higher in hemodialysis than in peritoneal dialysis. OPG and RANK-L did not depend on iPTH. The bone markers were significantly increased and correlated with serum iPTH, but not with OPG or RANK-L; neither OPG nor RANK-L correlated significantly with BMD. OPG was significantly higher in patients with acro-osteolysis. Conclusions OPG and RANK-L serum concentrations do not strongly reflect bone status in ESRF. However, OPG was significantly higher in patients with acro-osteolysis.