Type I Collagen C-telopeptide, CTX-I, Assay Kit

Catalog # 6033

INTRODUCTION

Collagen is the most abundant protein in the mammalian body and lends structural integrity to tissues as the primary component of the extracellular matrix (1). Type I collagen is the main component of bone, tendon, skin, and other tissues (2). In fact, type I collagen makes up 20% of bones by mass, which accounts for more than 90% of the organic components. As a result, degradation products of type I collagen can be detected in serum and urine in stages of bone loss or metabolism and can be potential markers of bone metabolism (3).

Proteinases mediate resorption of type I collagen from bone and generate specific peptide fragments of degraded collagen. For example, matrix metalloproteinases (MMPs) exclusively produce C-terminal degraded fragments (ICTP) from type I collagen, while cathepsin K produces-I fragments from the C-terminus and NTX-I fragments from the N-terminus of type I collagen (4). Because the proteinase activities differ among diseases and degraded fragments reflect the metabolism of type I collagen, immunoassays have been developed to monitor

the levels of these degraded fragments in biological fluids (5). Patients with osteoporosis display reduced bone mass. During disease progression, degraded peptides of type I collagen are observed

in serum as well as urine. Therefore, ICTP and NTX-I have been used as markers of osteoporosis (6-8). In addition, it was reported that CTX-I levels in urine are correlated with disease activity of osteoarthritis (9). Furthermore, cancers which metastasize to bone can affect the metabolism of type I collagen. Serum CTX-I levels correlate with prognosis of these cancers, especially prostate, lung, breast, and urinary

bladder cancers 

Thus, degraded type I collagen fragments are very useful tools for evaluating disease not only in humans, but also in mice, leading to the development of many mouse disease models for cancer, osteoporosis, osteoarthritis, and rheumatoid arthritis. Chondrex, Inc. has developed a CTX-I detection ELISA kit for mouse and human using a competitive assay system with a monoclonal antibody which recognizes conserved

peptide sequences in mouse and human .