Author/Editor     Avberšek-Lužnik, Ivica; Pečovnik-Balon, Breda; Rus, Igor; Marc, Janja
Title     Increased bone resorption in HD patients: is it caused by elevated RANKL synthesis?
Type     članek
Source     Nephrol Dial Transplant
Vol. and No.     , št. 20
Publication year     2005
Volume     str. 566-70
Language     eng
Abstract     Background. The receptor activator of nuclear factor kB ligand (RANKL), produced by osteoblasts/stromal cells, is a member of the RANK/RANKL/OPG system, which regulates bone resorption by osteoclasts. Since RANKL and osteoprotegerin (OPG) production in bone is influenced by parathyroid hormone (PTH), we measured serum RANKL and OPG concentrations in haemodialysis (HD) patients, who commonly hypersecrete PTH. We aimed to determine if clinically demonstrated PTH-enhanced bone resorption is a consequence of increased RANKL synthesis. Methods. RANKL, OPG, osteocalcin, intact PTH, bone-specific alkaline phosphatase, tartrate-resistant acid phosphatase 5b and beta-CrossLaps (CTx) were measured in blood samples from 80 HD patients and 50 age-matched controls. HD patients were stratified to tertiles according to their serum PTH levels: 29.3-103.0, 109.7-263.0 and 262.0-1700.0 pg/ml in the first, second and third tertiles, respectively. Results. Mean serum RANKL levels were 1.6 times higher in HD patients than in age-matched controls (1.36+- 0.39 vs 0.83+- 0.70 pmol/1; P < 0.001). All the measured bone markers significantly differed between patients and controls (P < 0.001). Spearman's tests of correlation showed a statistically significant association of RANKL with PTH, osteocalcin and CTx (r=0.322, P=0.004; r=0.231, P=0.039; and r = 0.230, P = 0.040, respectively). Mean serum RANKL levels were significantly different between PTH tertiles (P=0.003), but serum OPG levels were not (P=0.144). The highest RANKL levels were measured in the upper PTH tertile (1.54+- 0.39 pmol/l) and were significantly higher than in the middle or lower tertiles (1.27 +- 0.42 and 1.23+- 0.26 pmol/l, respectively; P=0.003).(Abstract truncated at 2000 characters)
Descriptors     KIDNEY FAILURE, CHRONIC
BONE RESORPTION
CARRIER PROTEINS
GLYCOPROTEINS
MEMBRANE GLYCOPROTEINS
AGE FACTORS
SEX FACTORS
CASE-CONTROL STUDIES
COLLAGEN
ISOENZYMES
OSTEOCALCIN
PARATHYROID HORMONES
PEPTIDE FRAGMENTS
RECEPTORS, CYTOPLASMIC AND NUCLEAR
RECEPTORS, TUMOR NECROSIS FACTOR
HEMODIALYSIS