Unique Features

  • Screening of Anti-Resorptive Drugs1,2,3
  • High throughput screening of osteoclastic resorptive activity
  • Multiple testing of single osteoclast cultures over time
  • Objective assessment of in vitro bone resorption
  • High correlation to pit area
  • Dynamic monitoring of bone cultures
  • Improved lab productivity due to multi-well screening formats
  • Easy to perform – one step incubation
  • A complete assay panel supporting bone research

The test is an enzyme-linked immunosorbent assay (ELISA) for the quantitative determination of degradation products of C-terminal telopeptides of type I collagen in bone cell culture supernatants.

Type I collagen accounts for more than 90% of the organic matrix of bone. During renewal of the skeleton bone matrix is degraded and consequently fragments of type I collagen are released into circulation.

The resorption process can be studied in vitro by culturing bone cells on devitalised slices of bone or dentin.

The CrossLaps® for Culture (CTX-I) ELISA is based on the observation that certain C-telopeptide degradation products from type I collagen released during osteoclastic bone resorption occur in the circulation as modified di-peptides. These modified (β-isomerised) and cross-linked di-peptides (Glu-Lys-Ala-His-Asp-β-Gly-Gly-Arg) must be covalently cross-linked through the lysine residue for signal in the CrossLaps® for Culture ELISA.

This epitope is present in type I collagen of many species, including human, bovine, elephant and chicken. However, it is not present in rat and mouse.

Zhuo Y et al., Inhibition of bone resorption by the cathepsin K inhibitor odanacatib is fully reversible. Bone. 2014 Jul 16;67C:269-280.

Leung P et al., The effects of the cathepsin K inhibitor odanacatib on osteoclastic bone resorption and vesicular trafficking. Bone. 2011 Oct;49(4):623-35.

Schaller S et al., In vitro, ex vivo, and in vivo methodological approaches for studying therapeutic targets of osteoporosis and degenerative joint diseases: how biomarkers can assist? Assay Drug Dev Technol. 2005 Oct;3(5):553-80.