The N-terminal telopeptide (NTX), also known as amino-terminal collagen crosslinks, is the

N-terminal The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...

telopeptide of fibrillar

collagens Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole ...

such as

collagen type I Type I collagen is the most abundant collagen of the human body. It forms large, eosinophilic fibers known as collagen fibers. It is present in scar tissue, the end product when tissue heals by repair, as well as tendons, ligaments, the endo ...

and type II. It is used as a

biomarker In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, ...

to measure the rate of bone turnover. NTX can be measured in the

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excretion, excreted from the body through the urethra. Cel ...

(uNTX) or serum (serum NTX). The peptide consists of eight amino acids with the sequence YDEKSTGG.

Usefulness of NTX as a biomarker

Evaluating an individual's rate of bone turnover, termed

bone remodeling Bone remodeling (or bone metabolism) is a lifelong process where mature bone tissue is removed from the skeleton (a process called ''bone resorption'') and new bone tissue is formed (a process called ''ossification'' or ''new bone formation''). ...

, directly may be important in assessing his or her potential nonsurgical treatment response as well as evaluating his or her risk of developing complications during healing following surgical intervention. To determine an individual's rate of bone turnover, numerous

s are available in the body fluids that can be correlated to this rate, and one such biomarker is NTX. However, while NTX does fluctuate in a very sensitive manner in line with bone resorption patterns, they are not very

specific Specific may refer to: * Specificity (disambiguation) * Specific, a cure or therapy for a specific illness Law * Specific deterrence, focussed on an individual * Specific finding, intermediate verdict used by a jury in determining the fina ...

, in that they may vary spontaneously without physiologic intervention. For example, NTX levels may drop by 50% from day to day with no treatment, thus, making NTX levels unconvincing evidence of treatment effect. Conversely, the serum CTX biomarker, described in 2000 by Rosen, appears to be a much more effective and valuable indicator of bone resorption rate.

References

{{DEFAULTSORT:N-terminal telopeptide Collagens Chemical pathology Bones Biomarkers Peptides

Usefulness of NTX as a biomarker

See also

References