Description
CTX-1, also referred to as either carboxy-terminal cross-linked telopeptide of type 1 collagen or C-terminal end of the telopeptide of type I collagen, is a marker of osteoporosis and bone resorption (1,2). CTX-1 is a common bone turnover marker (BTM) that can easily be measured in the plasma, serum, or urine (1-3). Bone turnover refers to the removal of old bones by resorption followed by generation of new bones (3). CTX-1 is released from intact collagen type 1 by cathepsin K cleavage and can be detected by an antibody against the eight amino acid sequence EKAHDGGR (2,4). Levels of CTX-1 show circadian rhythm variabilities altered by food intake, which makes timing of sample collection an important consideration and is typically done in a fasted state (1,3). Studies show that increased levels of CTX-1 along with bone-specific alkaline phosphatase (BSALP) is associated with increased risk for bone fractures and osteoporosis (3). The most common treatment for osteoporosis is bisphosphonates, which are classified as anti-resorptive drugs that slow the removal of bone (1,3). Another treatment is the Denosumab, a monoclonal antibody for receptor activator of NFkappaB ligand, which shows decreased levels of CTX-1 and other markers within the first 24-hours of treatment (1-3). Conversely, anabolic therapies add bone by focusing on the osteoclast and osteoblast populations. Romosozumab is one specific anabolic drug that showed quick decrease in CTX-1 levels following treatment (2,3).
References
1. Williams, C., & Sapra, A. (2020). Osteoporosis Markers. In StatPearls. StatPearls Publishing.
2. Szulc P. (2018). Bone turnover: Biology and assessment tools. Best Practice & Research. Clinical Endocrinology & Metabolism. https://doi.org/10.1016/j.beem.2018.05.003
3. Park, S. Y., Ahn, S. H., Yoo, J. I., Chung, Y. J., Jeon, Y. K., Yoon, B. H., Kim, H. Y., Lee, S. H., Lee, J., & Hong, S. (2019). Position Statement on the Use of Bone Turnover Markers for Osteoporosis Treatment. Journal of Bone Metabolism. https://doi.org/10.11005/jbm.2019.26.4.213
4. Cremers, C., Garnero, P., Seibel, M. J. (2008). Chapter 87- Biochemical Markers of Bone Metabolism. Principles of Bone Biology (Third Edition). https://doi.org/10.1016/B978-0-12-373884-4.00020-3.
Bioinformatics
| Alternate Names |
- Collagen Type 1 C-Telopeptide
- Cross Linked C-telopeptide of Type I Collagen
- CTX
- CTXI
|
