Mucus glycoprotein content of human cholesterol gallstones

Cholesterol gallstones were obtained from patients undergoing cholecystectomy and the mucus glycoprotein extracted. The biliary mucus glycoprotein was separated from other contaminants by Sepharose 4B gel filtration and the PAS staining excluded volume used to estimate mucus glycoprotein content of the gallstones. Hexosamine and sialic acid analysis of the glycoprotein indicated it was compositionally similar to the human mucus glycoprotein from bile. The mucus glycoprotein content of the nine stones analysed individually varied between 0.75 and 2.3 mg (a 3-fold variation) (1.27 +/- 0.16 mg, mean +/- SEM), whereas stone weight varied between 0.076 and 5.885 g (a 77-fold variation) (1.27 +/- 0.63 g, mean +/- SEM). When a pool of smaller stones, average weight 47 mg, was extracted, only 1.73 mg of glycoprotein was isolated, an average of 0.01 mg/stone. Analysis of the mucus glycoprotein by gel filtration on Sepharose 2B showed the majority of the glycoprotein was excluded as is the case with the mucus glycoprotein in bile. These results are consistent with biliary mucus glycoprotein being involved in the initial stages of gallstone formation but not in subsequent growth.     

Identification of Helicobacter pylori DNA in human cholesterol gallstones

BACKGROUND: The gallbladder mucosa secretes hydrogen ions and is covered by mucus. The environmental conditions for bacterial colonization are similar to those in the stomach. Gallbladder stones often contain DNA from enteric bacteria, but no compelling evidence demonstrates that Helicobacter spp. have been present. The aim of this study was to establish bacterial DNA profiles in cholesterol gallstones with special reference to Helicobacter pylori. METHODS: Cholesterol gallstones from 20 patients were subjected to polymerase chain reaction, bacterial profiling by temporal temperature gradient gel electrophoresis, automated DNA sequencing, and Southern blot analysis using a Helicobacter sp. specific primer. A nested ureI-PCR assay was used to discriminate between gastric and non-gastric H. pylori. RESULTS: TTGE, partial 16S rDNA sequencing, and hybridization analysis revealed the presence of DNA presumably representing a mixed bacterial flora in cholesterol gallstones, including H. pylori in the gallstone centres in 11 out of 20 patients. In three cases, the urel-PCR assay revealed non-gastric H. pylori. CONCLUSIONS: These data support the presence of DNA from a mixed bacterial population, including H. pylori in cholesterol gallstones, reflecting either that H. pylori is an indigenous part of a flora in the stone-containing gallbladder or, alternatively, that H. pylori colonization in the biliary tract predisposes to cholesterol gallstone formation.     

Black pigment gallstones with cholesterol gallstones in the same gallbladder

We studied 1312 consecutive patients who underwent surgery for gallstones in the biliary tract at one university hospital in Siena, Italy, with a systematic classification of gallstones found within the gallbladder. Of these patients, 1226 were found to have gallbladder stones; 94 of these had black pigment gallstones. Of these, 13 patients were found to have black pigment gallstones and cholesterol gallstones within their gallbladder. They all had multiple black pigment gallstones, usually very small (all <6 mm diameter), in association with larger cholesterol stones in the gallbladder lumen. The cholesterol gallstones were single in seven cases, double in two cases, and multiple in four cases. All 13 of these patients with black pigment stones in association with cholesterol stones had histologic evidence of either adenomyomatosis or Rokitansky-Aschoff sinuses in the gallbladder wall. In nine of the 13 patients, the black pigment stones were located both in the gallbladder lumen and in close association with the gallbladder wall (in areas of adenomyomatosis or in Rokitanski-Aschoff sinuses). In the other four patients, the stones were found in close association with the gallbladder wall alone and not freely mobile within the gallbladder lumen. It is concluded that cholesterol stones and black pigment stones may be found in the same gallbladder. This association is infrequent with an incidence of 13 of 1226 (1.06%) in our series. There appears to be some relationship between the formation of the black pigment stones and the presence of adenomyomatosis or Rokitanski-Aschoff sinuses. However, the pathogenesis of these two compositionally distinctly different types of stones within the same gallbladder is not understood and deserves further study.     

Calcium carbonate in cholesterol gallstones

CaCO3 has been studied in twelve gallstones in which cholesterol predominated. Different polymorphs of CaCO3, as well as carbonate-apatite, were characterised by X-ray diffraction, polarised light microscopy and scanning electron microscopy. Crystals and rhombohedral aggregates of calcite, aggregates of small crystals and tabular crystals of vaterite and fibrous radial aggregates in the form of ooliths were found. In microscopic studies on sections of the stones, CaCO3 was localised mainly in the periphery in the form of layers or bands associated with calcium bilirubinate which was deposited in close relation to it. The phenomena contributing to the precipitation of CaCO3 are discussed, as is the importance of the latter in resistance to the pharmacologic treatment of gallstone disease.     

Diet and cholesterol gallstones

A group of 101 female patients with gallstones were compared to 101 agematched controls. The patients with gallstones had a statistically significant (p=0.0005) increased intake of calories, irrespective of dietary composition. Psychologic stresses were more frequent in patients with gallstones (p<0.001); the following factors were not significantly different in the two groups: body weight, working conditions, and physical exercise.     

Etiology of cholesterol gallstones.

Formation of pure cholesterol stones is initiated by an excessive intake of highly purified carbohydrates, a large intake of animal fats and a restricted intake of vegetable fibers. When the protein content of the lithogenic diet was reduced, mixed or combined stones were formed in golden hamsters. These experimentally, dietarily produced gallstones had compositions and fine structures similar to those of human gallstones. Some mentions were made on black stones which were found in the aged golden hamsters fed with lithogenic diets.     

Helicobacter pylori in the etiology of cholesterol gallstones

GOALS: We aimed to investigate the presence of bacterial structures in cholesterol gallstones and particularly presence of Helicobacter spp/H. pylori in gallstones by microbiologic cultivation, histopathologic staining, and polymerase chain reaction (PCR). BACKGROUND: Many studies suggest that different mechanisms are responsible for the formation of pigmented gallstones and cholesterol gallstones. Recently, studies showed that infection could have an important role in the formation of cholesterol gallbladder stones. STUDY: We examined 77 mixed cholesterol gallstones. After cholecystectomy, gallbladder cultures were done for H. pylori and other bacterium. Gallbladder has also been examined by three histopathologic staining methods (Warthin-Starry, hematoxylin eosin, and gram staining) for Helicobacter spp. In addition, 16S rRNA-PCR amplification was performed for Helicobacter spp in gallstones. Twenty postmortem gallbladders without gallstones were investigated by the same histopathologic and PCR methods for Helicobacter spp. as a control group. RESULTS: Different bacterium were isolated from 22 gallbladder samples (12 Escherichia coli, 8 Pseudomonas, and 2 clostridium) and H. pylori was isolated in 6 gallbladder samples. Helicobacter spp was found in 7 gallstones by PCR amplification. Helicobacter-like organisms were demonstrated in 18 samples by three different histopathologic methods. Helicobacter-like organisms were also found in five samples by the same histopathologic methods (Warthin-Starry, hematoxylin-eosin, and gram staining). Only four samples were found positive for Helicobacter spp/H. pylori by all methods. CONCLUSIONS: Bacterial population including H. pylori could have a possible role in the formation of cholesterol gallstones.     

Bacterial DNA in mixed cholesterol gallstones

OBJECTIVE: Numerous investigators have proposed a role for bacteria in biliary lithogenesis. We hypothesized that bacterial DNA is present in gallstones, and that categorical differences exist between gallstone type and the frequency of bacterial sequences. METHODS: Polymerase chain reaction (PCR) was used to amplify bacterial 16S rRNA and uidA (encoding Escherichia coli [E. coli] beta-glucuronidase) genes in different types of gallstones. PCR products were sequenced. RESULTS: Bacterial 16S rRNA and uidA DNA sequences in E. coli were detected in all brown pigment, common bile duct, and mixed cholesterol gallstones (n = 14). In contrast, only one (14%) of seven pure cholesterol gallstones yielded a PCR product. Most (88%) mixed cholesterol gallstones yielded PCR amplification products from their central, as well as their outer, portions. Sequenced products possessed 88-98% identity to 16S rRNA genes of E. coli and Pseudomonas species. CONCLUSIONS: Bacterial DNA sequences are usually present in mixed cholesterol (to 95% cholesterol content), brown pigment, and common bile duct, but rarely in pure cholesterol gallstones. The presence of bacterial beta-glucuronidase is also suggested. The role of bacteria and their products in the formation of mixed cholesterol gallstones, which comprise the majority of cholesterol gallstones, warrants further study.     

Qualitative and quantitative comparison of gallbladder proteins from patients with and without cholesterol gallstones

Amino acid analysis and protein electrophoretic techniques were used to determine whether qualitative and quantitative gallbladder protein abnormalities exist in patients with cholesterol gallstones in Inner Mongolia. Gallbladder bile osmotic pressure measurement was determined and correlations were sought between the protein concentration and osmotic pressure of gallbladder bile. Protein concentrations and bile osmolality were higher in patients with cholesterol gallstones than in controls without biliary tract disease. A correlation between the protein concentration and osmotic pressure was found in gallbladder patients but not in controls (patients: r=0.83, P<0.05; controls: r=0.74, P<0.1).     

The organic matrix of gallstones

Dissolution of gallstones consisting of cholesterol, calcium carbonate, or calcium phosphate in different solvents left an amorphous organic gel-like substance (the matrix). Matrix from cholesterol stones could be colourless but was usually orange, yellow, or brown while that from calcium carbonate and calcium phosphate stones was almost invariably coloured black or dark brown. These pigments were also shown to be organic and amorphous. The amount of matrix present and its structure varied with the texture of the crystalline material. Irrespective of their composition, laminated pieces of material yielded compact laminated matrix of the same shape as the original piece and areas of loose crystalline material gave small pieces of non-cohesive matrix. Only large cholesterol crystals which usually radiate from the stone nucleus had no associated matrix.     

Dissolution of cholesterol gallstones in vitro. Gallstone matrix content and diameter, not cholesterol content, predict gallstone dissolution in monooctanoin

The goal of this study was to identify the structural and compositional features of human gallstones that influence in vitro gallstone dissolution in the cholesterol solvent monooctanoin. Gallstones were obtained from 86 consecutive patients who had at least three morphologically similar stones. One stone from each patient was dissolved in ethanol/ether to determine cholesterol and matrix composition. The remaining two matched stones were dissolved in either monooctanoin plus ethanol (n = 86) or monooctanoin plus 2-mercaptoethanol (n = 86). The thiol reducing agent 2-mercaptoethanol has been previously shown to solubilize the isolated gallstone matrix and to accelerate the dissolution of intact, small cholesterol stones. Stone matrix content and initial diameter had the most significant predictive value for stone dissolution (p less than 0.0001 for each), whereas cholesterol content had no predictive value (p = 0.558). Stones incubated in monooctanoin containing 2-mercaptoethanol dissolved more rapidly than those incubated in monooctanoin plus ethanol (16.7% of initial weight per day vs. 13.8% of initial weight per day, p less than 0.0001). Matrix content correlated significantly with the difference in dissolution rate between stones dissolved in monooctanoin plus ethanol or monooctanoin plus 2-mercaptoethanol (p less than 0.0001). These data indicate that the matrix content of human cholesterol gallstones significantly inhibits in vitro stone dissolution in the cholesterol solvent monooctanoin. This finding may be relevant to the clinical dissolution of gallstones.     

Composition of pigmented centers of cholesterol gallstones

Most cholesterol gallstones have visually pigmented centers, but it is unclear whether this represents simple co-precipitation of pigment with cholesterol during stone nidation or nidation on a true pigment stone center. To clarify this issue, we selected from among 67 sets of cholesterol gallstones, 12 sets with the most conspicuously pigmented centers. The composition of the centers and the peripheries of these 12 stones was analyzed using infrared spectroscopy and compared with that of 10 black pigment gallstones. The pigmented centers of cholesterol stones contained 80.1 +/- 7.9% (mean +/- S.E.) cholesterol, 6.2 +/- 3.4% calcium bilirubinate (only 4 of the 12 centers had measurable calcium bilirubinate), trace amounts of calcium phosphate and no calcium carbonate or calcium palmitate. The peripheral areas of the cholesterol stones contained 91.6 +/- 2.3% cholesterol and no detectable calcium salts. For comparison, the composition of the centers of 10 black pigment gallstones was 13.5 +/- 2.2% cholesterol, 28.2 +/- 5.3% calcium bilirubinate, 5.5 +/- 2.4% calcium phosphate and 10.6 +/- 5.8% calcium carbonate. The composition of only one cholesterol stone center (15.8% cholesterol, 26.8% calcium bilirubinate) resembled that of a pigment stone, but even this center differed from that of a typical pigment stone in that it contained only a trace amount of calcium phosphate and no calcium carbonate. Thus, the chemical composition of pigmented centers of cholesterol gallstones is quantitatively different from that of black pigment stones, suggesting that cholesterol gallstones do not form on a pigment stone nidus.     

Different susceptibilities to the formation of cholesterol gallstones in mice

In the search for an animal model of genetic determinants of cholesterol cholelithiasis, we found strain, gender and individual differences in mice. Male black (C57BL6J) mice had a 50% incidence of cholesterol gallstones after they consumed lithogenic food similar to that used by Tepperman et al. for 2 weeks, whereas similarly treated male agouti (CBA/J) mice and females of both strains were free of gallstones. The male and female mice of both strains were fertile at 8 weeks of age, and the male black mice were first susceptible to induction of gallstones at 24 weeks of age. Male agouti mice of the same age did not form gallstones until they had consumed the lithogenic food for 8 weeks. The gallbladder biles of both strains were supersaturated with cholesterol during the lithogenic regimen. The male agouti mice had much higher fractional turnover rates of [24-14C]cholic acid than did the male black mice. In spite of their small total cholate pools, the agouti mice had higher rates of new cholate synthesis than did the black mice. The rate of disappearance of [1,2-3H]cholesterol from the blood was higher in the male agouti than in the black mice. The gallbladders of the agouti mice contained less bile and weighed less empty than gallbladders of the black mice. They also did not increase in volume in response to the lithogenic diet as much as gallbladders of the black mice. The difference in gallstone induction times between male and female black mice was as great as the difference between the two strains.(ABSTRACT TRUNCATED AT 250 WORDS)     

Replacement of cholesterol gallstones by murideoxycholyl taurine gallstones in prairie dogs fed murideoxycholic acid

The effect of two hydrophilic bile acids, murideoxycholic acid (3 alpha,6 beta-dihydroxy-5 beta-cholanoic acid) and ursodeoxycholic acid, on cholesterol and bile acid metabolism and hepatic pathology and gallstone composition was studied in the prairie dog. Cholesterol gallstones were induced by feeding a diet containing 1.2% cholesterol for 75 days. The animals were divided into six groups, and gallstone regression was studied as follows: groups 2 and 5, chow plus 0.2% cholesterol; groups 3 and 6, chow plus 0.2% cholesterol plus 0.15% ursodeoxycholic acid; groups 4 and 7, chow plus 0.2% cholesterol plus 0.15% murideoxycholic acid. Animals in groups 2 to 4 were killed after an additional 6 wk; animals in groups 5 to 7 were killed after an additional 12 wk. Gallstone dissolution did not occur in any group. The gallstones in groups 2, 3, 5 and 6 were typical cholesterol aggregates, as determined by polarized light microscopy and Fourier transform infrared spectrometry. The gallstones of the murideoxycholic acid group were large, solitary, dark stones that appeared radiopaque under 22 kVp x-ray examination. Scanning electron microscopy showed that in these stones the cholesterol crystals had been replaced by an amorphous material, both within the stone and on the stone surface. Chemical analysis indicated that at the end of 12 wk the calcium/sodium salt of the taurine conjugate of murideoxycholic acid (murideoxycholyl taurine) comprised 70% of the stones; protein, cholesterol and small amounts of other bile salts were also present. In vitro studies confirmed the insolubility of the sodium and calcium salts of murideoxycholyl taurine. These studies indicate that the hydrophilic bile acids, murideoxycholic acid and ursodeoxycholic acid, did not achieve gallstone dissolution under the conditions used. In the animals fed murideoxycholic acid, an insoluble calcium salt of murideoxycholyl taurine replaced cholesterol as the major constituent of gallbladder stones. This is the first example of an insoluble dihydroxy taurine-conjugated bile acid; administration of the unconjugated bile acid induced precipitation of a kind of gallstone not previously reported. The final result was transformation of cholesterol stones to bile salt stones.     

Hepatic cholesterol metabolism in patients with gallstones.

Relative rates of cholesterol and bile acid synthesis were estimated in patients with cholesterol gallstones and biliary obstruction by determining the hepatic activities of 3-hydroxy-3-methylglutaryl-CoA reductase and cholesterol 7 alpha-hydroxylase, the respective rate-determining enzymes for cholesterol and bile acid synthesis. As compared with eight control studies, 3-hydroxy-3-methylglutaryl-CoA reductase activity was 27% higher in 12 gallstone subjects, but 75% lower in 5 subjects with biliary obstruction. Cholesterol 7 alpha-hydroxylase activity was reduced in the gallstone (47% lower) and biliary obstruction (78% lower) subjects. Liver cholesterol concentrations were 56% higher in the gallstone and 53% higher in the biliary obstruction subjects than the control group. These findings suggest that the pathogenesis of gallstones is related to both increased cholesterol synthesis and decreased bile acid formation, whereas cholesterol accumulates in biliary obstruction because of defective removal since cholesterol production is low.