# Immobilizing hydroxycholesterol with apatite on titanium surfaces to induce ossification

**Authors:** Cen Chen, Hyeong Cheol Yang, In-Seop Lee

PMC · DOI: 10.1186/2055-7124-18-16 · Biomaterials Research · 2014-10-20

## TL;DR

This study shows that combining hydroxycholesterol with apatite on titanium surfaces can enhance bone formation both in lab and animal tests.

## Contribution

A novel method of immobilizing hydroxycholesterol with apatite on titanium surfaces to induce ossification is introduced.

## Key findings

- Apatite/20α-HC coating showed similar cell viability to apatite coating, unlike other HC variants.
- ALP activity was significantly enhanced by immobilizing HC with apatite compared to apatite alone.
- In vivo tests showed improved mineral deposition with higher concentrations of HC/apatite coatings.

## Abstract

Immobilizing bioactive molecules and osteoconductive apatite on titanium implants have investigated direct ossification. In this study, hydroxycholesterol (HC) was immobilized with apatite on titanium through simply adsorption or sandwich-like coating. Three kinds of hydroxycholesterol were chosen to induce ossification: 20α-hydroxycholesterol (20α- HC), 22(S)-hydroxycholesterol (22(S)-HC) and 25-hydroxycholesterol (25-HC).The effects of HC/apatite coating on ossification abilities were evaluated in vitro and in vivo.

At 6 d, adsorbed apatite/25-HC and apatite/22(S)-HC coating exhibited some cytotoxicity, while the cell viability of apatite/20α-HC coating was similar as apatite coating. Immobilizing HC with apatite significantly enhanced the ALP activities compared with apatite coating. There was no significant difference in ALP value between adsorbed apatite/HC coating and sandwich-like apatite/HC/apatite coating. When compared with apatite coating, the mineral deposition improved by adsorbed HC with apatite at higher concentration in vivo.

When compared with apatite coating, immobilizing HC with apatite coating induced the ossification in vitro and in vivo.

## Linked entities

- **Chemicals:** 20α-hydroxycholesterol (PubChem CID 440711), 22(S)-hydroxycholesterol (PubChem CID 168038), 25-hydroxycholesterol (PubChem CID 65094), apatite (PubChem CID 10207414)

## Full-text entities

- **Genes:** Hc (hemolytic complement) [NCBI Gene 15139] {aka C5, C5a, He, Hfib2}, ATHS (atherosclerosis susceptibility (lipoprotein associated)) [NCBI Gene 470] {aka ALP}
- **Diseases:** cytotoxic (MESH:D064420), platelet aggregation (MESH:D001791)
- **Chemicals:** cholesterol (MESH:D002784), 22(S)-HC (MESH:C003585), hydroxyapatite (MESH:D017886), penicillin (MESH:D010406), 4-nitrophenyl phosphate (MESH:C008644), calcium (MESH:D002118), HC (MESH:D006888), CaP (MESH:D002130), MgCl2 (MESH:D015636), EtOH (MESH:D000431), CO2 (MESH:D002245), ascorbate (MESH:D001205), CaO (MESH:C016538), NaOH (MESH:D012972), DPBS (MESH:C012939), streptomycin (MESH:D013307), penicillin-G (MESH:D010400), 20alpha- HC (MESH:C025813), 25-HC (MESH:C007997), Triton X-100 (MESH:D017830), acetone (MESH:D000096), Alizarin Red S (MESH:C004468), glucose (MESH:D005947), CaCl2 (MESH:D002122), Apatite (MESH:D001031), PBS (MESH:D007854), beta-glycerophosphate (MESH:C031463), magnesium (MESH:D008274), oxysterol (MESH:D000072376), water (MESH:D014867), sphingolipid (MESH:D013107), Ti (MESH:D014025), BME (-), calcium phosphate (MESH:C020243)
- **Species:** Mus musculus (house mouse, species) [taxon 10090], Rattus norvegicus (brown rat, species) [taxon 10116], Homo sapiens (human, species) [taxon 9606]
- **Cell lines:** C3H10T1/2 — Mus musculus (Mouse), Spontaneously immortalized cell line (CVCL_0190)

## Full text

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## Figures

5 figures with captions in the complete paper: https://tomesphere.com/paper/PMC4552360/full.md

## References

28 references — full list in the complete paper: https://tomesphere.com/paper/PMC4552360/full.md

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Source: https://tomesphere.com/paper/PMC4552360