Distribution of phosphatidylcholine molecular species between mixed micelles and phospholipid-cholesterol vesicles in human gallbladder bile: dependence on acyl chain length and unsaturation.

Booker, M.; Ww, LaMorte; Ahrendt, SA; Lillemoe, K. D.; Pitt, H. A.

doi:10.1016/s0022-2275(20)41403-8

Cited by 24 publications

(4 citation statements)

References 24 publications

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“…The molar percentages of phosphatidylcholine molecular species in each lecithin used in the study are reported in [14]. Molecular species of lecithin are asymmetrically distributed between vesicles and micelles in human bile and MB systems [15,16]. The results of this study demonstrated that lecithin hydrophobicity within a physiological range considerably affects bile metastability as well as the CH crystal nucleation process.…”

Section: The Degree Of Hydrophobicity Of Various Lecithin Species By Hplcmentioning

confidence: 81%

Lecithin hydrophobicity modulates the process of cholesterol crystal nucleation and growth in supersaturated model bile systems

Ochi

Tazuma²,

Kajiyama

1996

Biochemical Journal

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The present study was performed to determine whether the degree of lecithin hydrophobicity regulates bile metastability and, therefore, affects the process of cholesterol crystallization. Supersaturated model bile (MB) solutions were prepared with an identical composition on a molar basis (taurocholate/lecithin/cholesterol, 73:19.5:7.5; total lipid concentration 9 g/dl) except for the lecithin species; egg yolk phosphatidylcholine, soybean phosphatidylcholine, 1-palmitoyl-2-linoleoyl-sn-phosphatidylcholine, dilinoleoyl phosphatidylcholine and dipalmitoyl phosphatidylcholine. Each MB solution was incubated and sequentially examined. Video-enhanced contrast microscopy demonstrated that the rate of vesicular aggregation and fusion correlated with the degree of lecithin hydrophobicity, and that the rate of cholesterol crystal nucleation correlated with the degree of lecithin hydrophilicity. In MBs containing less hydrophobic lecithin, needle-like crystals developed and transformed into mature plate-like crystals, whereas classical plate-like crystals were consistently observed in MBs composed of hydrophobic lecithin. Laser-diffraction particle size analysis demonstrated that the increase in lecithin hydrophobicity enlarged the vesicle dimension, enhancing its cholesterol-holding capacity. Correlation between vesicular cholesterol packing density and lecithin hydrophobicity suggests that the process of bile cholesterol nucleation and growth is regulated, in part, by acyl chain unsaturation in lecithin. Since the composition of biliary lecithins is responsive to dietary manipulations, this study provides new insights into the prevention of cholesterol gallstones.

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Section: The Degree Of Hydrophobicity Of Various Lecithin Species By Hplcmentioning

confidence: 81%

Lecithin hydrophobicity modulates the process of cholesterol crystal nucleation and growth in supersaturated model bile systems

Ochi

Tazuma²,

Kajiyama

1996

Biochemical Journal

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“…The most abundant bile salts in human bile are glycocholate (GCH 30 mol %), glycochenodeoxycholate (GCD 29 mol %), taurocholate (TCH 12 mol %), taurochenodeoxycholate (TCD 11 mol %), glycodeoxycholate (GDX 9 mol %), and taurodeoxycholate (TDX 2 mol %). , It has been reported that 95% of the phospholipids (PLs) in bile are secreted as phosphatidylcholine (PC), principally as two molecular species 1-palmitoyl, 2-linoleyl (16:0-18:2) phosphatidylcholine or 1-palmitoyl, 2-oleoyl (16:0-18:1) phosphatidylcholine (POPC). ,, Given this knowledge, we chose to model bile using pure POPC and GDX, which we believe is representative of the mixture found in bile. The choice of GDX was validated by an initial series of experiments.…”

Section: Resultsmentioning

confidence: 99%

“…26,31 It has been reported that 95% of the phospholipids (PLs) in bile are secreted as phosphatidylcholine (PC), principally as two molecular species 1-palmitoyl, 2-linoleyl (16:0-18:2) phosphatidylcholine or 1palmitoyl, 2-oleoyl (16:0-18:1) phosphatidylcholine (POPC). 26,32,33 Given this knowledge, we chose to model bile using pure POPC and GDX, which we believe is representative of the mixture found in bile. The choice of GDX was validated by an initial series of experiments.…”

Section: ■ Resultsmentioning

confidence: 99%

Digestion of Phospholipids after Secretion of Bile into the Duodenum Changes the Phase Behavior of Bile Components

Birru¹,

Warren²,

Ibrahim³

et al. 2014

Mol. Pharmaceutics

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Bile components play a significant role in the absorption of dietary fat, by solubilizing the products of fat digestion. The absorption of poorly water-soluble drugs from the gastrointestinal tract is often enhanced by interaction with the pathways of fat digestion and absorption. These processes can enhance drug absorption. Thus, the phase behavior of bile components and digested lipids is of great interest to pharmaceutical scientists who seek to optimize drug solubilization in the gut lumen. This can be achieved by dosing drugs after food or preferably by formulating the drug in a lipid-based delivery system. Phase diagrams of bile salts, lecithin, and water have been available for many years, but here we investigate the association structures that occur in dilute aqueous solution, in concentrations that are present in the gut lumen. More importantly, we have compared these structures with those that would be expected to be present in the intestine soon after secretion of bile. Phosphatidylcholines are rapidly hydrolyzed by pancreatic enzymes to yield equimolar mixtures of their monoacyl equivalents and fatty acids. We constructed phase diagrams that model the association structures formed by the products of digestion of biliary phospholipids. The micelle-vesicle phase boundary was clearly identifiable by dynamic light scattering and nephelometry. These data indicate that a significantly higher molar ratio of lipid to bile salt is required to cause a transition to lamellar phase (i.e., liposomes in dilute solution). Mixed micelles of digested bile have a higher capacity for solubilization of lipids and fat digestion products and can be expected to have a different capacity to solubilize lipophilic drugs. We suggest that mixtures of lysolecithin, fatty acid, and bile salts are a better model of molecular associations in the gut lumen, and such mixtures could be used to better understand the interaction of drugs with the fat digestion and absorption pathway.

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“…For example, partitioning of PC species in bile between micelles and vesicles was shown to be strictly determined by sn-1 chain length and the degree of non-saturation at both the sn-1 and sn-2 positions. 1 Chain length can also play a role in cholesterol solubility. 2 Finally, PC composition changes were linked to Alzheimer's disease, 3 to cortex lesions in rats, 4 or to Duchenne muscular dystrophy.…”

Section: Introductionmentioning

confidence: 99%

Structural Characterization of Phosphatidylcholines by Atmospheric Pressure Photoionization Mass Spectrometry

Delobel

Touboul

Laprévôte

2005

Eur J Mass Spectrom (Chichester)

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The potential of atmospheric pressure photoionization was investigated for the structural analysis of phosphatidylcholine lipids (PCs). [M+H]+ ions of high abundance were obtained, along with several fragment ions. Three of these dissociation products corresponded to quite unusual fragmentation pathways but allowed the determination of both the nature and the position on the glycerol backbone (sn-1 or sn-2) of the fatty acyl chains. The loss of a methyl group from the choline head was also observed. These results suggest a complex ionization mechanism in APPI. However, this method proved to be very powerful for the rapid structural analysis of PC species without using MS/MS experiments.

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Distribution of phosphatidylcholine molecular species between mixed micelles and phospholipid-cholesterol vesicles in human gallbladder bile: dependence on acyl chain length and unsaturation.

Cited by 24 publications

References 24 publications

Lecithin hydrophobicity modulates the process of cholesterol crystal nucleation and growth in supersaturated model bile systems

Lecithin hydrophobicity modulates the process of cholesterol crystal nucleation and growth in supersaturated model bile systems

Digestion of Phospholipids after Secretion of Bile into the Duodenum Changes the Phase Behavior of Bile Components

Structural Characterization of Phosphatidylcholines by Atmospheric Pressure Photoionization Mass Spectrometry

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