Circulating levels of osteoprotegerin and receptor activator of NF-kappaB ligand in patients with chronic renal failure.
BACKGROUND
Osteoprotegerin (OPG) is a recently identified cytokine that acts as a decoy receptor for the receptor activator of nuclear factor-kappaB ligand (RANKL). OPG and RANKL have been shown to be important regulators of osteoclastogenesis. The aim of this study was to investigate the relationship between the OPG-RANKL system and bone mineral metabolism in patients with chronic renal failure (CRF).


METHODS
Serum OPG, RANKL, osteocalcin, cross-linked c-telopeptide of type I collagen (ICTP), intact parathyroid hormone (PTH), bone alkaline phosphatase and cystatin C levels were measured in 40 chronic hemodialysis male patients and 32 age- and sex-matched healthy controls. Their lumbar spine bone mineral density (LS-BMD) was measured by dual energy X-ray absorptiometry.


RESULTS
Serum OPG, RANKL, PTH, bone alkaline phosphatase and cystatin C levels were significantly increased in patients with CRF. Serum OPG was positively correlated to serum RANKL and cystatin C. Positive correlations were found between serum RANKL and cystatin C and ICTP. LS-BMD was significantly lower in patients with CRF than in controls. In patients with CRF, LS-BMD was inversely correlated to serum RANKL and cystatin C, whereas it was positively correlated to serum OPG.


CONCLUSIONS
The OPG-RANKL system is involved in the pathogenesis and regulation of bone turnover in CRF. Circulating levels of OPG and RANKL may be useful markers to assess turnover renal osteopathies.
Shaarawy
Mohamed
M
Endocrinology and Maternal Biochemistry Labs, Department of Obstetrics and Gynecology, Faculty of Medicine, Cairo University, Cairo, Egypt. mohamedshaarawy@yahoo.com
Fathy
Shadia A
SA
Mehany
Nagy L
NL
Hindy
Odette W
OW
D000328:Adult; D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D055316:Cystatin C; D015891:Cystatins / Q000097:blood; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000503:physiopathology; D008024:Ligands; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D053244:Osteoprotegerin / Q000097:blood*; D053245:RANK Ligand / Q000097:blood*
D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D008024:Ligands; D053244:Osteoprotegerin; D053245:RANK Ligand; C505688:TNFSF11 protein, human; D015675:Osteocalcin