OBJECTIVE: To compare 5 different assays measuring collagen degradation in rheumatoid arthritis (RA). METHODS: Daily serum samples and 3 consecutive 24 h urine samples were obtained from 25 patients with RA and 20 control subjects. Levels of pyridinoline (PYD), deoxypyridinoline (DPYD), n-telopeptide (NTx), CrossLaps (XL), and carboxy-terminal peptide of type I collagen (ICTP) were determined by ELISA or radioimmunoassay. PYD, DPYD, NTx, and XL were measured in urine and expressed as a ratio of the amount of crosslink to mmoles of creatinine (Cr). ICTP was determined in serum. The day-to-day variability of urinary collagen crosslink levels and serum ICTP was assessed over 3 day hospitalization. RESULTS: Four of the 5 markers were significantly elevated in the RA cohort compared to controls: PYD (nmol)/Cr (median 33.8 vs 19.3; p = 0.0001), NTx (nmol)/Cr (median 22.5 vs 13.8; p = 0.01), XL (microg)/Cr (median 191.4 vs 126.1; p = 0.01), and ICTP (microg/l) (median 5.8 vs 3.7; p = 0.001). In the RA group, higher levels of the markers were associated with concomitant prednisone therapy. The levels of the 4 urine markers and of ICTP in serum exhibited little day-to-day variability. CONCLUSION: Biochemical evidence of increased collagen degradation can be readily observed in RA using simple quantitative assays. These measures have minimal short term, day-to-day variability and hence may be useful to assess the effect of potentially disease modifying therapies.
OBJECTIVE: To compare 5 different assays measuring collagen degradation in rheumatoid arthritis (RA). METHODS: Daily serum samples and 3 consecutive 24 h urine samples were obtained from 25 patients with RA and 20 control subjects. Levels of pyridinoline (PYD), deoxypyridinoline (DPYD), n-telopeptide (NTx), CrossLaps (XL), and carboxy-terminal peptide of type I collagen (ICTP) were determined by ELISA or radioimmunoassay. PYD, DPYD, NTx, and XL were measured in urine and expressed as a ratio of the amount of crosslink to mmoles of creatinine (Cr). ICTP was determined in serum. The day-to-day variability of urinary collagen crosslink levels and serum ICTP was assessed over 3 day hospitalization. RESULTS: Four of the 5 markers were significantly elevated in the RA cohort compared to controls: PYD (nmol)/Cr (median 33.8 vs 19.3; p = 0.0001), NTx (nmol)/Cr (median 22.5 vs 13.8; p = 0.01), XL (microg)/Cr (median 191.4 vs 126.1; p = 0.01), and ICTP (microg/l) (median 5.8 vs 3.7; p = 0.001). In the RA group, higher levels of the markers were associated with concomitant prednisone therapy. The levels of the 4 urine markers and of ICTP in serum exhibited little day-to-day variability. CONCLUSION: Biochemical evidence of increased collagen degradation can be readily observed in RA using simple quantitative assays. These measures have minimal short term, day-to-day variability and hence may be useful to assess the effect of potentially disease modifying therapies.
Authors: Péter Rass; Angéla Pákozdi; Péter Lakatos; Erika Zilahi; Sándor Sipka; Gyula Szegedi; Zoltán Szekanecz Journal: Rheumatol Int Date: 2006-01-31 Impact factor: 2.631
Authors: Anne Sofie Siebuhr; Anne C Bay-Jensen; Diana J Leeming; Adam Plat; Inger Byrjalsen; Claus Christiansen; Désirée van de Heijde; Morten A Karsdal Journal: Arthritis Res Ther Date: 2013-08-14 Impact factor: 5.156