These markers include the formation markers of type I collagen turnover, serum N-terminal (PINP) and C-terminal (PICP) propeptides of type I procollagen, and serum N-terminal propeptide of type III procollagen (PIIINP), as well as the resorption markers serum cross-linked C-terminal telopeptide
of type I collagen (ICTP) and urine cross-linked N-telopeptides of type I collagen (Ntx) and deoxypyridinoline (DPD) (1-5).
Fasting levels of urinary N-terminal cross-linking telopeptide
of type I collagen (NTX) decreased significantly up to 6 months, but not thereafter.
 Urinary N telopeptide
is the stable degradation end product, which could be measured both in the serum and urine.
Serum levels of interleukin (IL)-6 (1:1000, Santa Cruz, USA), tumor necrosis factor-a (TNF-a) (1:1000, Santa Cruz, USA), tartrate-resistant acid phosphatase 5b (TRACP-5b) (1:1000, Abcam, Cambridge, UK), and cross-linked carboxy-terminal telopeptide
of type 1 (CTX-1) (collagen, 1:1000, Abcam, Cambridge, UK) were also tested using the same procedure.
beta-crosslaps (urine, serum), C-terminal type-1 collagen
Study of the distribution by age group of serum cross-linked C-terminal telopeptide
of type I collagen and procollagen type I N-propeptide in healthy Japanese women to establish reference values.
Blood sample was collected for measurement of Apelin-13, Procollagen type-I N propeptide (PINP) and Cross-linked carboxy terminal telopeptide
of type-I collagen (ICTP), and BMD was tested with a dual-energy X-ray absorptiometry scanner.
Markers of resorption, including serum and urinary C-terminal telopeptide
and urinary N-terminal telopeptide
, and markers of bone formation, including osteocalcin, procollagen I intact N-terminal propeptide, and bone-specific alkaline phosphatase, begin to rise as early as 3 months postoperatively, and the increases in some studies appear to persist beyond the first postoperative year, even after correction of nutritional deficiencies and stabilization of weight loss (4, 5).
Bone biochemical markers such as C-terminal telopeptide
(CTX) and N-terminal telopeptide
(NTX) will reflect on the bone resorption process and breakdown of the collagen fibers.
Measurement of Serum CTX (C-Terminal Cross-Linked Telopeptide
of Type I Collagen) Value.
A main outcome measure in this study was urinary levels of C-terminal crosslinking telopeptide
of type II collagen (CTX-II), a breakdown product of collagen that serves as a useful indirect biomarker of joint destruction.