Reduced cholesterol metastability of hepatic bile and its further decline in gall bladder bile in patients with cholesterol gall stones

Ductal stones recurrence after extracorporeal shock wave lithotripsy for difficult common bile duct stones: Predictive factors

BACKGROUND & PURPOSE

Extra-corporeal shock wave lithotripsy (ESWL) can be considered in difficult common bile duct stones (DCBDS), with a success rate greater than 90% but data on stone recurrence after ESWL are limited. We performed a retrospective analysis to evaluate long-term outcomes in patients who underwent ESWL for DCBDS.

METHODS

From May 1992 to October 2012, patients who underwent ESWL treatment for DCBDS, not amenable to endoscopic extraction, were included. Data on long-term outcome were collected through phone interviews and medical records.

RESULTS

A total of 201 patients with a successful clearance of DCBDS after ESWL were included. During a median follow-up period of 4.64 years, 40 patients (20%) developed a recurrence of bile duct stones. Logistic regression analysis showed that the common bile duct diameter, gallstones presence and the maximum stone size were significantly associated with recurrence.

CONCLUSIONS

We observed a recurrence rate of 20% over a median follow-up of 4 years. Gallbladder stones, stone size and a dilated common bile duct diameter are risk factors for recurrent stone formation, while ursodeoxycholic acid treatment did not influence recurrence in our population.

Impaired human gallbladder lipid absorption in cholesterol gallstone disease and its effect on cholesterol solubility in bile

BACKGROUND & AIMS

The role of the gallbladder in gallstone pathogenesis is still unclear. We examined the effects of gallbladder mucosal lipid absorption on lipid composition and cholesterol crystallization in bile.

METHODS

The in vitro-isolated, intra-arterially perfused gallbladder model was used (1) to compare the absorption rates of lipids from standard bile by gallbladders obtained from 7 patients with cholesterol gallstones and 6 controls; and (2) to measure the microscopic cholesterol crystal detection time in cholesterol-enriched pig bile before and after lipid absorption by the pig gallbladder.

RESULTS

Control gallbladders, but not cholesterol gallstone gallbladders, significantly reduced cholesterol (P < 0.02) and phospholipid (P < 0.01) and increased bile salt (P < 0.01) molar percentages in bile over a 5-hour period by efficient and selective cholesterol and phospholipid absorption. A histomorphometric study of the epithelial cells showed significantly higher values for nuclear density (P < 0.01) and nuclear (P < 0.05) and cytoplasmic (P < 0.05) areas in the cholesterol gallstone than the control group. Sequential microscopy of cholesterol-enriched pig bile showed significantly shorter cholesterol filament (P < 0.01) and typical cholesterol plate (P < 0. 02) detection times before than after exposure of bile to the gallbladder lipid absorption.

CONCLUSIONS

In cholesterol gallstone disease, the human gallbladder epithelium loses its capacity to selectively and efficiently absorb cholesterol and phospholipids from bile, even if it is hyperplastic and hypertrophic. This epithelial dysfunction eliminates the positive effect that the normal gallbladder exerts on cholesterol solubility in bile and might be a pathogenetic cofactor for cholesterol gallstone formation.

Hepatic bile versus gallbladder bile: a comparison of protein and lipid concentration and composition in cholesterol gallstone patients

Many studies have demonstrated that gallbladder bile (but not hepatic bile) of animals or patients with cholesterol gallstones contains higher protein concentrations than does gallbladder bile of control patients without stones or with pigment stones. The underlying defect has not been elucidated. To establish whether there is net production or net absorption/degradation of protein by gallbladder epithelium for different classes of protein, paired samples of hepatic and gallbladder bile were obtained from fourteen patients with cholesterol gallstones during elective cholecystectomy. In these paired samples, lipid and protein composition were determined. To obtain the concentration ratio (CR) of protein and lipid, its concentration in the gallbladder was divided by the concentration determined in the paired hepatic bile sample. The CR of bile salts was used as a parameter for water absorption in the gallbladder. Of the biliary proteins that were determined only mucin, albumin, immunoglobulin (Ig) G, and aminopeptidase N appeared to increase in the gallbladder from another cause than water absorption. A strong correlation was found between mucin, albumin, and IgG. Haptoglobin, alpha1-acid glycoprotein, IgM, and IgA appeared to be absorbed by gallbladder epithelium in the majority of patients. In cholesterol gallstone patients, total protein concentration in gallbladder bile of cholesterol gallstone patients is increased when compared with hepatic bile. The increase in protein concentration cannot be explained for all bile samples solely by water absorption. In this study we show that the defect is largely caused by a selective increase in albumin, mucin, and IgG. All other proteins which were investigated are taken up by the gallbladder.

Human gallbladder mucosal function: effects on intraluminal fluid and lipid composition in health and disease

Gallbladder mucosal absorption of fluid during fasting is a well-known process. Indirect in vivo and recent in vitro evidence for physiologically relevant gallbladder absorption of cholesterol and phospholipids from bile has been observed in humans. The present study explored and compared by indirect means the relative efficiences of human gallbladder mucosal absorption of fluid and lipids in health and disease. Biliary lipids and pigment content were measured in fasting gallbladder bile samples obtained from gallstone-free controls and from four study groups: multiple and solitary cholesterol gallstone patients, and morbidly obese subjects with and without gallstones. Bile salts and pigment content were significantly greater in gallstone-free controls than in all other disease study groups. This was interpreted as evidence of more effective gallbladder mucosal fluid absorption in nonobese gallstone-free controls compared to that in all other groups. Correlation plot analyses of biliary lipids showed lower concentrations of phospholipids than expected from the index bile salt concentrations. The same was found for cholesterol concentrations but only in supersaturated samples. These findings were much more pronounced in gallstone free-controls and were accordingly interpreted as evidence of more efficient gallbladder absorption of both phospholipids and cholesterol in controls compared with that found in each of the disease study groups. Moreover, impaired gallbladder mucosal function, while invariably associated with cholesterol gallstone disease, was not found to be a necessary consequence of the physical presence of stones. It is concluded that efficient gallbladder mucosal absorption of both fluid and apolar lipids from bile is a normal physiological process that is often seriously impaired in the presence of either cholesterol gallstone disease or at least one of its precursor forms.

Serum and bile lipid levels in patients with and without gallstones

The aim of the present study was to investigate predisposing factors that lead to the formation of gallstones. In a group of 70 patients (51 with gallstones and 19 without, 20 possible risk factors were studied: percent of ideal body weight, the presence of superoxide dismutase in erythrocytes and in serum, lipid peroxide in serum, total serum cholesterol (Ch), high-density lipoprotein (HDL)-cholesterol (Ch), low-density lipoprotein (LDL)-Ch, very low-density lipoprotein (VLDL)-Ch, serum triglyceride (TG), HDL-TG, LDL-TG, VLDL-TG, serum bile acids (lithocholic acid, deoxycholic acid, chenodeoxy cholic acid, ursodeoxy-cholic acid, and cholic acid) and serum apolipoproteins (apo A-1, apo B-100, and apo A-1/apo B-100). Levels of apo B-100 and serum insulin in patients with gallstones were strikingly higher, and superoxide dismutase in erythrocytes was significantly lower than in individuals with no gallstones. Apo A-1 and HDL-Ch were also higher and LDL-Ch was lower in the gallstone group, albeit non-significantly so (P > 0.05) by t-test. However, Apo A-1, HDL-Ch, and LDL-Ch showed remarkably good discriminatory power in stepwise discriminant analysis of the 20 factors. Bile lipid composition was also measured and the cholesterol saturation index was calculated, but no significant differences were seen between the two groups. The results demonstrate that serum lipid patterns differ to some extent in patients with and without gallstones. Lipid derangement may contribute to the development of gallstone disease.

Lithogenicity of human bile is reduced by freezing and thawing

We examined the effects of freezing and thawing upon the nucleation time and the distribution of cholesterol between micelles and vesicles in 9 human gallbladder and 7 hepatic biles. The nucleation time was significantly longer after freezing when compared to fresh samples (22.4 +/- 2.6 vs. 7.4 +/- 1.9 days, respectively). Concomitantly, a substantial shift of cholesterol from vesicles to micelles was noted, with the proportion of vesicular cholesterol decreasing from 26.5% +/- 6.0% in fresh biles to 8.6% +/- 2.3% after freezing. These effects were observed in all types of human biles, regardless of origin, cholesterol saturation or initial presence of cholesterol crystals, and were most notable after the first week of freezing. The decrease in vesicular cholesterol in all biles and the increase in nucleation time of gallbladder biles correlated with the time the samples had been in a frozen state. It is concluded that the lithogenic properties of human bile are not maintained during storage at -20 degrees C. Freezing results in a shift of cholesterol from vesicles to micelles and reduces the tendency of cholesterol to crystallize from bile samples.

The effects of dietary phospholipids enriched with phosphatidylethanolamine on bile and red cell membrane lipids in humans

The role of phospholipids in biliary cholesterol solubilization and crystallization has only recently begun to be appreciated. Phospholipid vesicles are believed to be the metastable carrier from which cholesterol nucleates. Cholesterol crystallization is influenced by the phospholipid species in bile. Feeding rats and hamsters with diets enriched in phospholipids or their precursors, especially ethanolamine, resulted in reduced cholesterol saturation of bile. Although whole phospholipids are normal dietary constituents, the effects and safety of phospholipid components have not been tested in humans. In the present study, we have evaluated the effects of a dietary phospholipid mixture, enriched with phosphatidylethanolamine, on human bile and red blood cell membrane lipid composition. Five ambulatory volunteers having a chronic indwelling T-tube, with an intact enterohepatic circulation, were investigated. Thirty-six grams of phospholipids (54% phosphatidylethanolamine, 54% linoleyl acyl chains) were added to their daily diet for fourteen days. Biliary nucleation time, cholesterol carriers, as well as plasma, red blood cell membrane, and bile lipid compositions, were monitored. Following phospholipid supplementation, the proportion of linoleyl chains (18:2) in biliary phospholipids increased significantly from 31.1 +/- 1.2 to 37.7 +/- 5.3%, while that of oleyl chains (18:1) decreased from 11.4 +/- 1.6 to 9.6 +/- 1.1%. These changes were accompanied by an increase of linoleate and its metabolite, arachidonate, in red cell membranes. Phospholipid feeding did not cause any side effects, and no significant changes in biliary nucleation time, cholesterol, phospholipid, or bile salt concentrations, or in the distribution of cholesterol within micelles or vesicles. We conclude that phospholipid feeding is safe, and can be effective as a vehicle for lecithin fatty acyl chain modulation of bile and lipid membranes. These findings may provide a basis for a controlled modulation of biliary phospholipids to increase cholesterol solubility in bile.