Telopeptides as markers of bone turnover in rheumatoid arthritis and osteoarthritis.
OBJECTIVE
The aim of the present study was to determine if urinary excretion of type I collagen N-terminal telopeptides (UrNTx) and deoxypyridinoline (UrDPD) and serum levels of type I collagen C-terminal telopeptides (SeCTx) differed in patients with rheumatoid arthritis (RA) compared with populations matched for age and gender with and without osteoarthritis (OA). The correlation of markers of bone turnover with disease activity in patients with RA or radiographic severity in patients with OA was also examined.


METHODS
Patients with RA aged >50 years (men) and >60 years (women) were identified from computer databases at two tertiary referral centres for rheumatology. Strict exclusion criteria were applied to avoid the effects of factors known to influence markers of bone turnover. Patients with RA and OA were matched for age and sex with a control population free of known arthritic disease and a population with OA. Bone markers were assayed in serum and urine. Urine markers were measured on three consecutive days and mean values used to minimize day-to-day variability of these analytes.


RESULTS
The level of UrNTx was elevated in patients with RA compared with normal controls and patients with OA. UrNTx and UrDPD correlated with markers of disease activity in patients with RA (erythrocyte -sedimentation rate and C-reactive protein), but not with -clinical signs of inflammation (swollen and tender joint counts). Patients with OA failed to show any correlation between markers of bone turnover and radiographic severity.


CONCLUSIONS
These data support a role for the use of UrNTx and UrDPD in further studies of the patho-physiology of RA and in longitudinal studies designed to modify the course of clinical disease.
Reid Rheumatology Laboratory, Walter and Eliza Hall Institute of Medical Research, Victoria, Australia. wong@wehi.edu.au
P K K
PK
Wong
L
L
Young
J H
JH
Vaile
L
L
Tan
J V
JV
Bertouch
J F
JF
Bleasel
C
C
White
D000368:Aged; D000596:Amino Acids / Q000378:metabolism* / Q000652:urine; D001172:Arthritis, Rheumatoid / Q000378:metabolism* / Q000503:physiopathology; D015415:Biomarkers / Q000032:analysis*; D016723:Bone Remodeling; D001862:Bone Resorption; D016022:Case-Control Studies; D003094:Collagen / Q000378:metabolism* / Q000652:urine; D024042:Collagen Type I; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism* / Q000503:physiopathology; D010455:Peptides / Q000378:metabolism* / Q000652:urine
D000596:Amino Acids; D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; C036020:deoxypyridinoline; D003094:Collagen