Measurement of OPG, RANKL, and TRAP5b in the serum of elderly patients with active paget's disease
Calcif Tissue Int 72, Abstract P11
Durham BH, Daroszewkska A, Fraser WD
The Royal Liverpool University Hospital, Liverpool, UK
Abstract
We have measured osteoprotegrin [OPG], the receptor activator of nuclear factor kappaB ligand [RANKL] and the osteoclast derived tartrate - resistant acid phosphatase 5b[TRAP5b]. in a cohort of 64 elderly patients with active Paget's disease, F31, M33, mean age 74.5yr range 55-88 yr. After venepuncture serum was separated as soon as possible and stored at -70°C until analysed , all assays were run at the same time so that the sera did not need re-thawing. OPG and RANKL ELISA kits were from Biomedica , Vienna, Austria and TRAP5b ELISA kit from SBA Sciences, Turku, Finland. In the RANKL assay only the soluble unbound fraction is measured.There was no significant differences between men and women in any of the assays so the cohort of patients was considered as one group. Mean, SD, range for OPG was 3.6,1.7, 0.7-8.9 pmol/L, for RANKL 7.4,4.7, 1.3-25.9 pmol/L and for TRAP5b 5.7,1.8,2.2-15.2 U/L. The ratio OPG/RANKL had a mean of 0.65,SD 0.42, range 0.13-1.50, there was no significant relationship between either OPG or RANKL and TRAP5b, the concentration of OPG was equal to, or greater than that of RANKL in 15/64 [23%] of patients. In our cohort of active Paget's patients OPG values were significantly lower compared with those of age-related normals 3.6±1.7 v 5.5±1.8 [p<0.05]; 8/64 [12.5%] were lower than the age-related reference range, whereas RANKL was significantly raised 7.4±4.7 v 3.8±2.0 [p<0.01] with 28/64 [44%] greater than an age-related reference range. TRAP5b was also raised 5.7±1.8 v 4.6±0.9 [p<0.05]with 17/64[26%] of values greater than an age-related reference range. The measurement of OPG, RANKL, and TRAP5b should advance our knowledge of osteoclastogenesis and particularly the communication between osteoblasts and osteoclasts in Paget's disease.