Journal of Lipid Research, Vol 35, 60-70, Copyright © 1994 by Lipid Research, Inc.

ARTICLES

Phospholipid molecular species influence crystal habits and transition sequences of metastable intermediates during cholesterol crystallization from bile salt-rich model bile

FM Konikoff, DE Cohen and MC Carey
Department of Medicine, Gastroenterology Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115.

Despite its importance in cholesterol gallstone formation, crystallization of cholesterol from bile is poorly understood, especially with respect to the influences of other biliary lipids. We reported recently (Konikoff et al. J. Clin. Invest. 1992. 90: 1155- 1160) that cholesterol can crystallize from model and native biles as filamentous crystals covered by a surface layer of lecithin molecules. During growth, filamentous crystals transformed via metastable intermediates into classical plate-like cholesterol monohydrate crystals. Using the same dilute (1.2 g/dl total lipid) bile salt-rich (97.5 moles %) model bile supersaturated with cholesterol, we have studied the effects of natural egg yolk, soy bean as well as single molecular species of lecithins, other phospholipids and related lipid classes on early filamentous cholesterol crystallization, as well as transformations between crystal habits and their growth to equilibrium cholesterol monohydrate plates. After extraction and derivatization, HPLC analysis revealed that the surfaces of filamentous crystals were enriched preferentially with lecithin molecular species having longer and more saturated sn-1 and sn-2 acyl chains compared to mixed lecithin species of whole bile. In contrast, the molecular species distribution of lecithins on equilibrium plate-like crystals resembled that of whole bile. After incubation of pre-formed anhydrous cholesterol and cholesterol monohydrate crystals in cholesterol-free lipid solutions, we demonstrated that surface-adsorbed lecithins were not preferentially enriched excluding nonspecific lecithin adsorption. Time-sequences and transformations between metastable crystalline intermediates were altered markedly by specific phospholipid species: model biles composed of saturated short-chain, medium-chain, and polyunsaturated long-chain lecithins induced rapid precipitation of short filamentous crystals that became plate-like slowly by an "arborization pattern." Long-chain saturated lecithins and natural sphingomyelins retarded cholesterol crystallization markedly, and filamentous as well as metastable intermediate crystals made transient appearances only after plate-like crystals had formed. These observations suggest that phospholipid molecular species and class influence the earliest events in cholesterol crystallization from bile salt-rich model bile. Furthermore, as the molecular species of lecithins adsorbed onto filamentous cholesterol crystals were more saturated than in whole bile and essentially identical to those in biliary vesicles, this finding provides chemical evidence for a vesicular origin of the critical cholesterol nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				J. Kasbo, B. Tuchweber, S. Perwaiz, G. Bouchard, H. Lafont, N. Domingo, F. Chanussot, and I. M. Yousef Phosphatidylcholine-enriched diet prevents gallstone formation in mice susceptible to cholelithiasis J. Lipid Res., December 1, 2003; 44(12): 2297 - 2303. [Abstract] [Full Text] [PDF]

				Y. V. Zastavker, N. Asherie, A. Lomakin, J. Pande, J. M. Donovan, J. M. Schnur, and G. B. Benedek Self-assembly of helical ribbons PNAS, July 6, 1999; 96(14): 7883 - 7887. [Abstract] [Full Text] [PDF]

				P PORTINCASA, K J VAN ERPECUM, and G P VANBERGE-HENEGOUWEN Cholesterol crystallisation in bile Gut, August 1, 1997; 41(2): 138 - 141. [Full Text] [PDF]