[Tartrate-resistant acid phosphatase--TRAP 5b--as a novel marker of bone resorption in patients with irreversible renal failure treated with dialysis].

UNLABELLED: The evaluation of renal osteodystrophy in everyday practise is based on measurements of non-invasive bone markers. TRAP 5b has been considered as a potentially useful marker of bone resorption rate. We assessed the clinical usefulness of TRAP 5b as a marker of bone resorption in renal osteodystrophy in comparison with standard marker which is intact parathormone (iPTH) level.

MATERIAL AND METHODS: We studied 84 patients: 61 on hemodialysis (HD) for 43 +/- 25 months (36M, 25F aged 59 +/- 25 yr.) and 23 on continuous ambulatory peritoneal dialysis (CAPD) for 47 +/- 28 months (12M, 11F, aged 53 +/- 23 yr). The following parameters were determined in serum: TRAP 5b, iPTH, Ca, P, total acid phosphatase (AP). Serum TRAP 5b activity was measured using a solid phase immunofixed enzyme activity assay Bone TRAP (SBA Finland). Intact PTH was measured using immunoradiometric assay (Incstar USA). According to iPTH level patients were divided into 3 subgroups: A--(iPTH < 100 pg/ml); B--(iPTH 100 - 450 pg/ml); C--(iPTH > 450 pg/ml).

RESULTS: We found significant correlation between iPTH and TRAP in dialysed pts. (r = 0.6764, p < 0.0001). In patients with high turnover renal osteodystrophy-group C significantly higher values of TRAP were found in comparison with patients with low turnover renal osteodystrophy-group A (7.5 +/- 1.4 vs. 2.9 +/- 1.4 p < 0.001). There was not significant correlation between values of TRAP and gender, cause of irreversible renal failure as well as method of dialysotherapy.

CONCLUSION: In conclusion, highly significant correlation between level of TRAP 5b and iPTH found in our study justifies using TRAP 5b as an important marker of bone resorption rate in clinical practice.