Cholesterol solubility

Gallstones. Bile acids keep cholesterol soluble in gallbladder bile. Therefore, they are used for the dissolution of cholesterol gallstones. Initial treatment... 

Enhancement of cholesterol solubility by high molecular weight DHS in river water, where solvent extraction of the radiolabeled cholesterol was ineffective as a means of recovery unless the OM content was altered by UV radiation. 

Biliary cholesterol saturation index (CSI) in nonacromegalic patients with cholesterol GBS (CH-GBS), acromegalic patients with Octreotide-associated GBS (OT-GBS), and stone-free patients before Octreotide treatment (No OT-GBS). "Hie value of CSI = 1.0 indicates the limit of cholesterol solubility points above the line are supersaturated, whereas those below the line are unsaturated with cholesterol. (All graphs show mean values SEMs.) Data taken from reference 18. 

Cohen, D.E. and Carey, M.C. 1991. Acyl chain unsaturation modulates distribution of lecithin molecular species between mixed micelles and vesicles in model bile. Implications for particle structure and metastable cholesterol solubilities. J. Lipid Res. 32, 1291-1302. 

Cholesterol soluble in methyl tert-butyl ether in the gallbladder... 

Flynn GL, Shah Y, Prakongpan S, et al. Cholesterol solubility in organic solvents. / Pharm Sci 1979 68 1090-1097. 

Bogardus JB. Unusual cholesterol solubility in water/glyceryl-l-mono-octanoate solutions. ] Pharm Sci 1982 71 ilQ-ill. 

Terpenes are reputed to increase cholesterol solubility in bile, though are less effective than bile acids. There are two such preparations available, Rowatinex and Rowachol , containing some combination of the following anethol, borneol, camphene, cineole, mendone, menthol, pipene and renchone, in olive oil. Direct contact dissolution by direct injection of organic solvents, such as methyl tert-butyl ether (MTBE), is sometimes used. 

The precise limits of cholesterol solubility in model bile solutions appear lower than first determined (H13, H23). 

The total lipid concentration in bile is an important factor affecting cholesterol solubility and must be taken into account when calculating biliary cholesterol saturation (C7). 

C7. Carey, M. C., and Small, D. M., The physical chemistry of cholesterol solubility in bile. 

H23. Holzbach, R. T., Marsh, M., Olszewski, M., and Holan, K., Cholesterol solubility in bile. Evidence that supersaturated bile is firequent in healthy man. /. CUn. Incest. 52, 1467-1479 (1973). 

Calculated Solubility Sphere for Cholesterol Solubility — RED Order (see Equation 10.5)... 

In our above proposed hypothesis for the in vivo formation of oxysterols, we attribute their occuiTence to the various phenomena that make it possible, (i) for various almost water-insoluble (at 25°C cholesterol solubility is approximately 0.2 mg/dl or 4.7 xM) cholesterol species to occur in serum, an aqueous medium [15], and (ii) to allow these species as lipoprotein entities to circulate in blood throughout our bodies. 

Fig. 16. Influence of oleic acid, lysolecithin, or lecithin concentration on cholesterol solubility in bile acid solution at a fixed concentration. The increment in cholesterol solubility with added polar lipids is indicated by the slope of the line, which is given in parentheses. Data from Neiderhiser and Roth (114), with their kind permission.

The solubility of cholesterol has been studied as a function of several physiologically important variables, such as the concentrations of various bile salts and phospholipids, e.g. [70, 71]. Carey [72] has generated extensive cholesterol solubility tables for native bile by identifying two key physicochemical variables, the bile salt-to-lecithin ratio and the total hpid concentration (bile salts -I- lecithin -I- cholesterol), that determine the solubility of cholesterol in bile [70]. These tables permit calculation of the litho-genic index or percent cholesterol saturation of native bile. 

Brown AW, Hang J, Dussault PH, Carr TP (2010) Phytosterol esto c[Pg.3458]

Note Basically, there are two types of fibers water soluble fiber (like oat bran) and non-soluble fiber (like wheat bran). Only soluble fiber is effective in lowering cholesterol. Soluble fiber dissolves in water. 

Several mechanisms by which plant sterols might affect cholesterol absorption have been proposed (Poliak and Kritchevsky, 1981 Ling and Jones, 1995). The interference with intestinal cholesterol absorption by plant sterols is probably related to the close resemblance in the chemical stmctures of these molecules, although the precise mechanisms are not yet fully understood. At present, reduced micellar solubility of cholesterol is thought to be the main mechanism by which plant sterols reduce cholesterol absorption. Ikeda et al. (1989) elegantly proved that cholesterol solubility in mixed micelles is reduced by plant sterols and plant stanols, in studies on rats. For 10 days rats were fed a diet enriched with cholesterol (0.5%, w/w of diet) alone, or together with... 

Ekwall and Baltcheffsky [265] have discussed the formation of cholesterol mesomorphous phases in the presence of protein-surfactant complexes. In some cases when cholesterol is added to these solutions a mesomorphous phase forms, e.g. in serum albumin-sodium dodecyl sulphate systems, but this does not occur in serum albumin-sodium taurocholate solutions [266]. Cholesterol solubility in bile salt solutions is increased by the addition of lecithin [236]. The bile salt micelle is said to be swollen by the lecithin until the micellar structure breaks down and lamellar aggregates form in solution the solution is anisotropic. Bile salt-cholesterol-lecithin systems have been studied in detail by Small and coworkers [267-269]. The system sodium cholate-lecithin-water studied by these workers gives three paracrystalline phases I, II, and III shown in Fig. 4.37. Phase I is equivalent to a neat-soap phase, phase II is isotropic and is probably made up of dodecahedrally shaped lecithin micelles and bile salts. Phase III is of middle soap form. The isotropic micellar solution is represented by phase IV. The addition of cholesterol in increasing quantities reduces the extent of the isotropic... 

A commercial emulsifying agent, glyceryl monooctanoate (monooctanoin), has been found to be an excellent solvent for cholesterol [278]. In vitro it dissolved mixed cholesterol gallstones more than twice as fast as did sodium cholate solutions which have been used as infusions for dissolution of retained cholesterol bile duct stones. Monooctanoin has also been tried by T-tube infusion in an attempt to effect direct dissolution of stones. Cholesterol solubility and dissolution kinetics are enhanced (Fig. 4.39). Monooctanoin infusions were well tolerated and some or all stones in 10 out of 12 patients were removed by dissolution by biliary tract infusion of monooctanoin over periods ranging from 4 to 21 days. 

Another hypothesis supports the idea that stearic acid is converted by the Stearoyl-CoA-Desaturase (SCD) enzyme into oleic acid, which does not affect blood cholesterol levels (Pai et al., 1997). Moreover, it seems that stearic acid does not suppress LDL receptors activity and, consequently, the plasma cholesterol level decrease. In vitro experiments have shown that stearic acid reduces cholesterol absorption by altering the synthesis of bile acids and cholesterol solubility. 

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