Haptoglobin-stimulated bone resorption in neonatal mouse calvarial bones in vitro

✍ Scribed by Ulf H. Lerner; Nils Fröhlander

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 498 KB
• Volume: 35
• Category: Article
• ISSN: 0004-3591
• DOI: 10.1002/art.1780350517

✦ Synopsis

Objective. To study the in vitro effects of human haptoglobin (Hp) on bone resorption and prostanoid formation.

Methods. Parietal bones were dissected out from neonatal mice that had been injected with '%a, and were cultured in chemically defined medium with or without test substances. Bone resorption was assessed by analysis of %a release. Prostanoid formation was quantified by analysis of the amount of prostaglandin E, (PGE,) in culture medium.

Results. Hp phenotype 2-1, in quantities 20.17 mg/ml, stimulated the release of 45Ca and the biosynthesis of PGE,, in a time-and dose-dependent manner. Hp-induced PGE, formation was abolished by indomethacin and flurbiprofen, whereas the stimulation of 45Ca release was only partially reduced.

Conclusion. These observations suggest that the acute-phase reactant Hp may contribute, by a humoral mechanism, to the bone resorption seen in chronic inflammatory processes.

In inflammatory conditions, cellular reactions are controlled by several locally produced and locally