Influence of phospholipid on bile salt binding to calcium hydroxyapatite and on the poisoning of nascent hydroxyapatite crystals

Masayuki Okido, Roger D. Soloway, Roger S. Crowther

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Glycine-conjugated, dihydroxy bile salts inhibit calcium hydroxyapatite (HAP) formation by binding to and poisoning nascent crystal embryos. Their taurine-conjugated counterparts bind less well to hydroxyapatite and do not inhibit its formation; but more hydrophobic, synthetic analogs of the taurine conjugated bile salts are inhibitors of hydroxyapatite formation. Because hydrophobicity is an important determinant of the ability of bile salts to inhibit hydroxyapatite crystal growth, experiments were performed to study the effect of the physiologically important mixed micelles of bile salt and phospholipid. Taurodeoxycholate/phosphatidylcholine (10:1) mixed micelles bound to HAP at lower total lipid concentrations than did pure taurodeoxycholate. At low total lipid concentrations, phosphatidylcholine (PC) binding appeared to predominate, suggesting that PC had a higher affinity than did taurodeoxycholate (TDC) for the HAP surface. Although glycodeoxycholate (3 mM) significantly (> 95%) inhibited hydroxyapatite precipitation, higher concentrations of taurodeoxycholate, either alone or mixed with phosphatidylcholine, did not affect hydroxyapatite formation. These results suggest that biliary phospholipids do not modulate the ability of bile salts to inhibit hydroxyapatite crystal growth.

Original languageEnglish (US)
Pages (from-to)321-325
Number of pages5
JournalLiver
Volume16
Issue number5
StatePublished - Oct 1 1996

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Keywords

  • Calcium phosphate
  • Cholelithiasis
  • Micelles
  • Surface properties

ASJC Scopus subject areas

  • Hepatology

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