Mucus glycoprotein biosynthesis in the human gall bladder: inhibition by aspirin

Therapeutic effect of yinchenhao decoction on cholelithiasis via mucin in the gallbladder and intestine

Cholelithiasis is a common and frequently occurring disease worldwide that belongs to the category of jaundice in traditional Chinese medicine. Yinchenhao decoction (YD) consists of Artemisia capillaris Thunb., Gardenia jasminoides J.Ellis, and Rheum palmatum L., and is traditionally used to treat jaundice, which has a significant therapeutic effect on cholelithiasis. Our study aimed to investigate the pathological mechanism of cholelithiasis and the therapeutic mechanism of YD via mucin in the gallbladder and intestine. YD was prepared and analyzed using HPLC. The supersaturation stability experiment was designed by the solvent-shift method. The cell transport experiment was conducted by coculture monolayers. The animal experiment was performed using a cholelithiasis model with a high-cholesterol diet. The related indicators were detected by automatic biochemical analyzer, PCR, western blot, or ELISA. Statistics were analyzed using χ2-tests and t-tests. As the results, in cholelithiasis, MUC5AC highly expressed in the gallbladder shortened cholesterol supersaturation and promoted cholesterol crystallization via the inflammatory cytokine signaling pathway; MUC2 highly expressed in the small intestine prolonged cholesterol supersaturation and promoted cholesterol absorption via the inflammatory cytokine signaling pathway. YD inhibited mucin expression in the gallbladder and intestine in a concentration-dependent manner for cholelithiasis treatment by inhibiting the inflammatory cytokine signaling pathway, which was attributed to the active components, including chlorogenic acid, geniposide, and rhein.

Effect of prednisolone administration on gallbladder emptying rate and gallbladder bile composition in dogs

OBJECTIVE To investigate effects of prednisolone administration on gallbladder emptying rate and gallbladder bile composition in dogs. ANIMALS 6 healthy Beagles. PROCEDURES Prednisolone was administered (2 mg/kg, SC, once daily for 2 weeks) to each dog and tapered over 2 weeks. Gallbladder emptying rate and bile composition were evaluated before and after administration of prednisolone for 2 weeks as well as 1 week after cessation of prednisolone administration. RESULTS Gallbladder emptying rate decreased significantly after prednisolone administration (median, 27%; range, 0% to 38%), compared with rate before administration (median, 59%; range, 29% to 68%), but then increased 1 week after cessation of administration (median, 45%; range, 23% to 48%). Gallbladder bile mucin concentration decreased significantly after prednisolone administration (median, 8.8 mg/dL; range, 6.2 to 11.3 mg/dL), compared with concentration before administration (median, 13.1 mg/dL; range, 10.7 to 21.7 mg/dL), but then increased 1 week after cessation of administration (median, 14.3 mg/dL; range, 9.6 to 26.7 mg/dL). Gallbladder taurochenodeoxycholic acid concentration decreased significantly after prednisolone administration (8.1 mmol/L; range, 6.8 to 15.2 mmol/L), compared with concentration before administration (median, 27.2 mmol/L; range, 22.0 to 31.9 mmol/L), but then increased 1 week after cessation of administration (median, 26.4 mmol/L; range, 15.1 to 31.5 mmol/L). CONCLUSIONS AND CLINICAL RELEVANCE A lower gallbladder emptying rate caused by prednisolone administration may be involved in the pathogenesis of gallbladder disease in dogs. Further studies are required to determine the clinical importance of lower gallbladder bile mucin concentrations caused by glucocorticoid administration in the pathogenesis of gallbladder disease in dogs.

Genetics of gallstone disease

Gallstone disease (GSD) is one of the most common biliary tract disorders worldwide. The prevalence, however, varies from 5.9-21.9% in Western society to 3.1-10.7% in Asia. Most gallstones (75%) are silent. Approximately half of symptomatic gallstone carriers experience a second episode of biliary pain within 1 year. These individuals are at increased risk of developing acute cholecystitis, acute cholangitis, and biliary pancreatitis. As can be expected, these complications burden health care systems because of their invasive nature and surgical cost. Factors that contribute to gallstone formation include supersaturation of cholesterol in bile, gallbladder hypomotility, destabilization of bile by kinetic protein factors, and abnormal mucins. Epidemiologic studies have implicated multiple environmental factors and some common genetic elements in gallstone formation. Genetic factors that influence gallstone formation have been elaborated from linkage studies of twins, families, and ethnicities. Accumulating evidence suggests that genetic factors play a role in GSD.

Mucin genes in gallstone disease

Gallstone disease is a complex disorder that can be caused by environmental influences, common genetic factors and their interactions. Three major pathogenic abnormalities are considered to involve in gallstone formation: cholesterol supersaturation in bile, precipitation and nucleation of excess cholesterol, and gallbladder hypomotility, while, mucin takes part in the cholesterol nucleation process. Up to date, more than 20 mucin genes have been reported, 9 of them are identified at the mRNA and/or protein level in native gallbladder and its associated diseases. In the gallbladder, mucin is essential for best protection against detergent effect of high concentration of bile acids. Over the past decade, the properties, expressions and functions of the gallbladder mucins are delineated in animal and human studies. Alteration expressions of mucins are thought to response during the pathogenesis of gallstone formation. Moreover, recent genetic association study demonstrated mucin gene polymorphisms may also influence susceptibility to gallstone disease. This review is not to provide a complete coverage of all the aspects of mucin glycoproteins, but focus on the role and expression of mucins involve in the regulation of cholelithogenesis.

The role of mucoregulatory agents after continence-preserving urinary diversion surgery

PURPOSE

The postsurgical use of N-acetylcysteine, octreotide, and other agents to reduce mucus accumulation after urinary diversion procedures is described.

SUMMARY

Patients undergoing continence-sparing bladder resection are at risk for infection and stone formation due to mucus accumulation. In addition to N-acetylcysteine, agents studied for mucoregulatory control in such patients include aspirin, urea, ranitidine, and octreotide. N-acetylcysteine has high mucolytic activity in vitro, and positive outcomes with instillations of 20% N-acetylcysteine solution have been reported in some patients. Significant mucus reductions were reported in small numbers of patients treated with oral ranitidine 300 mg daily or instillations of 30 mL of urea 40% solution, while the benefits of aspirin are more questionable. To date, there has been only one randomized controlled trial comparing various agents for mucus reduction after reconstructive bladder surgery; the results indicated no significant benefits with the use of N-acetylcysteine, aspirin, or ranitidine. In one small study (n = 40), the use of subcutaneous octreotide immediately before and for 15 days after surgery was reported to yield significant reductions in mucus production, the need for bladder irrigation to clear blockages, and the mean duration of hospital stays.

CONCLUSION

Various agents evaluated for mucus control after urinary diversion procedures (oral ranitidine or aspirin, N-acetylcysteine or urea instillations, and subcutaneous octreotide), while reportedly effective for some patients, remain of questionable benefit. More research is needed to define the optimal role of these agents for this indication.

T-cell function is critical for murine cholesterol gallstone formation

BACKGROUND & AIMS

The formation of cholesterol gallstones is a complex process involving contributions from genes and environmental factors. Although gallbladder inflammation is believed to be common during cholelithogenesis, the role of immunologic factors is unknown.

METHODS

The role of adaptive immunity in cholesterol cholelithogenesis was analyzed utilizing immunocompetent Helicobacter spp.-infected and -uninfected BALB/c and congenic immunodeficient Rag2(-/-) (Rag) mice. Lymphocyte transfer studies were performed to determine which cellular subset was responsible for cholesterol gallstone formation. Also, gallbladder inflammation was quantified to determine the nature of the inflammatory response associated with cholelilithogenesis.

RESULTS

When fed a lithogenic diet for 8 weeks, wild-type mice developed significantly more cholesterol gallstones (27%-80% prevalence) than Rag mice ( approximately 5%, P < .05). Helicobacter spp.-infected BALB/cJ mice displayed statistically significant increases in cholesterol gallstone prevalence compared with uninfected mice (81% vs. 39%; P < .05). Transfer of splenocytes or T lymphocytes to Rag2(-/-) mice increased stone prevalence markedly (26% and 40% respectively; P < .05), whereas transfer of B cells was not appreciably cholelithogenic (13%). The adaptive immune response increased the expression of gallbladder Muc genes and accumulation of mucin gel. In addition, T cells and cholesterol monohydrate crystals induced proinflammatory gene expression in the gallbladder, which likely contributes to gallbladder dysfunction.

CONCLUSIONS

These studies indicate that T cells are critical in murine cholesterol cholelithogenesis. Furthermore, cholesterol monohydrate crystals induce expression of proinflammatory cytokines in a T-cell-dependent fashion. Acquired immunity and inflammation are likely to be crucial factors in cholesterol gallstone pathogenesis, rather then merely the result of cholelithogenesis.

Mucus production after transposition of intestinal segments into the urinary tract

Following transposition into the urinary tract, intestinal segments continue to produce mucus and problems related to excessive production do not to diminish with time. Currently, 20 human mucin genes have been described and their protein products partially or fully characterised. As the use of transposed intestinal segments in urology increases, there is now a need for a better understanding of mucins at the gene and protein levels. There is also a need for urologists to be aware of the many complications related to excess mucus production. Whilst effective therapeutic measures to reduce mucus production and its related complications remain elusive, it is now clear that without such effective mucoregulatory agents the quality of life of patients will continue to be less than satisfactory. This review describes the biology of mucus and the problems related to continued production following transposition of intestinal segments into the urinary tract. Difficulties related to quantification of urinary mucus, in addition to the structural and mucin gene changes that occur in transposed segments, are addressed.

Mucin and phospholipids determine viscosity of gallbladder bile in patients with gallstones

AIM: An increased viscosity of gallbladder bile has been considered an important factor in the pathogenesis of gallstone disease. Besides lipids and proteins, mucin has been suggested to affect the viscosity of bile. To further clarify these issues we compared mucin, protein and the lipid componEnts of hepatic and gallbladder bile and its viscosity in patients with gallstones.

METHODS: Viscosity of bile (mPa.s) was measured using rotation viscosimetry in regard to the non Newtonian property of bile at low shear rates.

RESULTS: Biliary viscosity was markedly higher in gallbladder bile of patients with cholesterol (5.00 ± 0.60 mPa.s, mean ± SEM, n = 28) and mixed stones (3.50 ± 0.68 mPa.s; n = 8) compared to hepatic bile (0.92 ± 0.06 mPa.s, n = 6). A positive correlation between mucin and viscosity was found in gallbladder biles (r = 0. 65; P < 0.001) but not in hepatic biles. The addition of physiologic and supraphysiologic amounts of mucin to gallbladder bile resulted in a dose dependent non linear increase of its viscosity. A positive correlation was determined between phospholipid concentration and viscosity (r = 0.34, P < 0.005) in gallbladder biles. However, no correlation was found between total protein or the other lipid concentrations and viscosity in both gallbladder and hepatic biles.

CONCLUSION: The viscosity of gallbladder bile is markedly higher than that of hepatic bile in patients with gallstones. The concentration of mucin is the major determinant of biliary viscosity and may contribute by this mechanism to the role of mucin in the pathogenesis of gallstones.

Gallstone formation. Local factors

Bile supersaturation is necessary for cholesterol gallstones to form. Not all people with supersaturated bile form gallstones, however, and additional factors must be present. The role of pronucleating substances has been extensively studied. Of these, proteins, especially mucin, are best understood. Mucin is secreted by the gallbladder epithelium and may act as a nidus for crystal nucleation. Other proteins that may act as pronucleators include alpha 1-acid glycoprotein, alpha 1-antichymotrypsin, phospholipase C, and a small calcium binding protein. The role of antinucleating factors is less well understood. Certain drugs, including octreotide and ceftriaxone, may also predispose to stone formation. Another local factor is gallbladder stasis, a well-known risk factor for pigment stone formation. More recent research has focused on the role of bacterial infection, which has long been believed to be a factor in pigment gallstone formation. Newer data also support a role for infection in cholesterol gallstone pathogenesis. Additionally, genetic factors that may predispose a patient to cholesterol gallstones have been identified in mice and in humans.

Nonsteroidal antiinflammatory drug use and gallstone disease prevalence: a case-control study

OBJECTIVES

Conflicting results on the relationship between gallstone disease and the use of nonsteroidal antiinflammatory drugs (NSAIDs) have been reported, but studies on the effect of NSAID use in populations not selected on the basis of a high risk for gallstone development are still lacking.

METHODS

We conducted a case-control study involving 216 patients, regular NSAID users (43 men and 173 women) consecutively admitted to a rheumatology department, suffering from rheumatoid arthritis (n = 147), osteoarthritis (n = 49), and ankylosing spondylitis (n = 20). Two-hundred sixteen patients who were not NSAID users, matched for gender, age, and body mass index, consecutively admitted to a medical department for various medical pathologies, acted as a control group. All patients underwent upper abdomen ultrasonography.

RESULTS

The overall prevalence of gallstones was similar in the two groups: 24.0% in NSAID users (15.7% actual stones and 8.3% previous cholecystectomy) and 21.3% in controls (13.9% gallstones and 7.4% cholecystectomy). The prevalence of gallstone disease was significantly higher in women than in men, and the mean age was higher in gallstone patients than in gallstone-free patients, in both groups. No significant differences in type and duration of arthritis condition, type and dose of NSAID taken, and duration of treatment between gallstone patients and gallstone-free patients were found. On logistic regression analysis only female gender, aging, and family history of gallstone disease were significantly associated with the presence of gallstones, whereas no relationship between NSAID use and gallstone disease was found.

CONCLUSIONS

Chronic NSAID ingestion does not seem to prevent gallstones in arthritis patients; in these patients gallstone disease is associated with classic risk factors (female gender and age).

Ground squirrel model for cholelithiasis: role of epithelial glycoproteins

The cholesterol-fed Richardson's ground squirrel (Spermophilus richardsonii) has proven to be an effective animal model in which to study factors that influence cholesterol gallstone formation and associated alterations in the gallbladder epithelium. Ground squirrels of either sex, fed a 2% cholesterol-enriched diet, exhibit cholesterol monohydrate crystal precipitation within 24 hours and macroscopically visible cholesterol stones by 3 weeks. Data on bile chemistry, biliary cholesterol precipitation, and various mucosal alterations occurring prior to, during, and after stone formation were collected using sampling intervals from 6 hours to 20 weeks on the diet. The results indicate that mucin hypersecretion appears to be more closely related to the initiation of nucleation than does either bile calcium of pH. Mucus hypersecretion begins within 18 hours of diet initiation and continues throughout the 20 week experimental period. Apical excrescences became more common and were larger in size during the early stages of cholelithiasis. Administration of aspirin during the experimental period demonstrated an inhibition of mucin synthesis and release. Gallstones were not formed in these aspirin-treated animals. A lectin-binding panel for 10 epithelial glycoprotein-related sugars indicated the mucin secreted by the gallbladder epithelium of 7 day experimental animals differed from that of controls. The most obvious difference was the abolition of WGA binding in the experimental animals, suggesting an absence of sialic acid expression in the mucin during the lithogenic process. Ultrastructural histochemistry indicated that both sulphomucin and sialomucin were present in the secretory granules and within the surface mucus layer of both experimental and control animals. Experimental animals, however, exhibited a significant predominance for sulphomucin. This pattern varies from that typically seen in other regions of the gastrointestinal tract where sialomucins predominate during pathologic processes.

Characterization of glycoproteins in the epithelial cells of human and other mammalian gallbladder. A review

The mammalian gallbladder mucosa is lined by a simple columnar epithelium. Typical surface epithelial cells (principal cells) contain short microvilli, secretory granules, dense bodies, mitochondria and Golgi apparatus. Dense bodies are thought to be lysosomes. Secretory granules contain mucous glycoproteins which are released to the lumen by exocytosis. Oligosaccharide side chains of mucous glycoproteins may provide a favorable environment for nucleation of cholesterol in gallstone formation; therefore they have been studied during the past decades. Histochemical techniques allow the in situ identification of carbohydrates at both the cellular and subcellular levels. The oligosaccharide chains of principal cell mucous glycoproteins have been studied by classical histochemical techniques (PAS, alcian blue, HID, etc). These techniques indicate that mammalian gallbladder mucous glycoproteins are heavily sulphated, whereas sialic acid residues are scarce. Neutral mucins have not been described in the mammalian gallbladder. Electron microscopic studies have located the oligosaccharide chains in secretory granules and Golgi apparatus. More recently, lectins (molecules which specifically recognize and bind with different saccharides or saccharide sequences) have been applied for the intracellular localization of carbohydrate residues. Lectin histochemistry has detected fucose, galactose, N-acetylglucosamine, N-acetylgalactosamine and N-acetylneuraminic acid residues in mucous granules, Golgi apparatus and apical membrane of human principal cells. Mannose residues were observed only in dense bodies. The combined use of deglycosylation procedures and lectin histochemistry has revealed a variety of terminal sequences in oligosaccharide chains of gallbladder mucous glycoproteins: Neu5Ac(alpha 2-3)Gal(beta 1-3)GalNAc, Neu5Ac(alpha 2-3)Gal(beta 1-4)GlcNAc and Gal(beta 1-4)GlcNAc. This technology also suggested the occurrence of N-linked oligosaccharides in the dense bodies of principal cells. Mucous granules mainly contained mucin-type O-linked oligosaccharides although some N-linked chains have also been detected. Gallstone formation is probably a complex process depending on multiple factors. Mucous glycoproteins are one of the factors involved in this process. Histochemical methods offer an excellent research tool for the characterization of glycoproteins in the epithelial cells of the gallbladder, thus contributing to the elucidation of the pathophysiology of gallstone formation.

Biochemical and morphological correlations in human gallbladder with reference to membrane permeability

There is good evidence that gallbladder epithelium is permeable to a diverse range of molecules which move into the epithelial cell from the lumen or the basement membrane. Morphological investigations have shown both secretory mucous droplets, components of the endocytosis pathway together with evidence of a system allowing passage of molecules across the basement membrane. This indicates that the gallbladder epithelium may be influenced by molecules presented via the apical and basal membranes, complicating our understanding of gallbladder function, particularly in disease. Gallbladder disease increases the proteoglycan content of the basement membrane, but the implication of this in terms of permeability remains to be defined. Indeed, it remains unknown whether this precedes disease or is a manifestation of the disease process. The removal of water from hepatic bile by gallbladder involves two counter ion transport systems. Autoradiography shows that ion transport occurs into the lateral intracellular spaces but it remains unclear whether this leads to a hypertonic solution in these spaces causing an osmotically driven water absorption or if the process involves an osmotically linked isotonic secretion. These ion pumps are reversible, for water is absorbed during the interdigestive phase but fluid is secreted into the lumen during digestion or in the presence of disease. Appropriate neural stimulation can increase or decrease fluid absorption from the lumen while vasoactive intestinal peptide or secretin promote fluid secretion, probably mediated by prostaglandins leading to raised cyclic AMP acting at the cellular level. Immediate control may depend on intracellular Ca2+ which activates a calmodulin-protein kinase, phosphorylating the counter ion transporters to downregulate their activity. Failure of this regulatory process may explain the initial increase in bile concentrating potential seen in the development of gallstones although the mechanism of such failure remains unknown. More concentrated bile increases movement of biliary compounds into gallbladder epithelial cells which alter gallbladder function in a complex manner. Secondary bile acids are raised in gallstone disease and increase permeability of the gallbladder epithelium to molecules including cholesterol. This cholesterol absorbed from the lumen may have paramount importance to gallbladder function. Raised biliary cholesterol reduces gallbladder motility, possibly by increasing the amount of cholesterol in gallbladder muscle membranes and reducing contraction in response to cholecystokinin. However, increased secondary bile acids are also associated with an alteration in phospholipid acyl groups which may alter ion transport activity and/or cholesterol solubility within the micelle/vesicle. As the acyl groups show increased arachidonate levels the production of prostaglandins could be raised, although currently it is not known if this phospholipid arachidonate enters the epithelial cells. In addition, gallbladder inflammation is associated with raised phospholipase A2 activity, leading to formation of fatty acids and lysophospholipid which causes membrane damage. The fatty acids are likely to displace cholesterol from the micelle but may also act directly on the epithelium, possibly increasing prostaglandin production and thus stimulating mucin secretion. Increased mucin secretion is seen early in gallstone disease but the evidence presently available cannot determine if this is a causative factor.

Aspirin changes the secretion rate and amino acid composition of human small intestinal mucin in subjects with ileal conduits

The effect of aspirin on the rate of secretion and amino acid composition of human ileal mucin was studied, using subjects with ileal conduits as a model system in which mucin secreted from the ileal conduit tissue is flushed out in the urine and can be measured and analysed. Aspirin (600 mg per day, administered orally) increased the daily mucin output by 37-104% in subjects by days 3 or 4, but thereafter the mucin output declined to below the baseline level by day 10. Mucin samples, purified from the ileal conduit urine during the control period and during aspirin administration, were compared. There were no discernible changes in the degree of polymerisation or the density, but during aspirin administration the amino acid composition was significantly changed, and in particular threonine and proline were enriched. One possible explanation, consistent with the compositional analyses, is that the N- and C-terminal regions of the mucin subunits have been cleaved off and lost during aspirin administration. The observed changes in mucin secretion may have implications for the mechanism of the toxic effects of aspirin on the small intestine by altering the barrier properties of the mucus layer.

Cholesterol gallstone formation in man and potential treatments of the gallbladder motility defect

Cholelithiasis affects 10-15% of the adult population in Western society, and about 75% of gallstones are of cholesterol type. Hepatic hypersecretion of cholesterol with the formation of instable cholesterol-rich vesicles in bile, an imbalance between nucleation-inhibiting and nucleation-promoting proteins with further aggregation of cholesterol crystals in a gallbladder with a motility defect (stasis), all play a role in the pathogenesis of cholesterol gallstones. Experimental animal models suggest that gallstone formation can be prevented by improving gallbladder emptying. Thus, a better understanding of the causes underlying the impaired gallbladder motor function in patients with gallstones might lead to the selection of therapeutic approaches for those individuals who are at increased risk for the formation or recurrence of gallstones. The present article focuses on current concepts and theories on the pathogenesis of cholesterol gallstones with emphasis on the gallbladder motility defect. Several treatment strategies for the correction of gallbladder hypomotility are also discussed.

Biosynthesis of a human gall-bladder mucin

Mucin glycoproteins play an important role in the initial stages of gall-stone formation by a currently largely unknown mechanism. Understanding the structure of gall-bladder mucin is necessary to comprehend the mechanism by which cholesterol monohydrate crystals aggregate. Three successive CsCl-gradient-ultracentrifugation steps were used to purify human gall-bladder mucin from gall-bladder tissue. The isolated macromolecules had a typical mucin-like monosaccharide composition and appeared as heterogeneous high-M(r) glycoproteins on SDS/PAGE. A polyclonal antiserum was raised against these molecules and the specificity of the antiserum was ascertained by immunoblotting. The antiserum specifically stained mucous granules at the apical side of all gall-bladder epithelial cells in neck, fundus and body. The antibody was subsequently used to immunoprecipitate the mucin and biosynthetic intermediates from gall-bladder-tissue homogenates. An early biosynthetic precursor of the isolated mucin was identified by SDS/PAGE as a single polypeptide with an apparent M(r) of approx. 470,000. This precursor protein was converted after 1 h into a heterogeneous high-M(r) glycoconjugate with an electrophoretic mobility similar to that of the purified mucin. The mature mucin, but not the precursor, was secreted into the culture medium, starting at 1 h. As shown by SDS/PAGE under non-reducing conditions, the precursors form disulphide-linked oligomers. Using the N-glycosylation inhibitor tunicamycin, the apparent M(r) of the precursor was decreased to approx. 410,000, indicating that N-linked glycan chains are attached to the precursor polypeptide.

Indomethacin decreases viscosity of gallbladder bile in patients with cholesterol gallstone disease

There is experimental evidence that inhibition of cyclooxygenase with nonsteroidal anti-inflammatory drugs may decrease cholesterol gallstone formation and mitigate biliary pain in gallstone patients. The mechanisms by which NSAIDs exert these effect are unclear. In a prospective, controlled clinical trial we examined the effects of oral indomethacin on the composition of human gallbladder bile. The study included 28 patients with symptomatic cholesterol or mixed gallstones. Of these, 8 were treated with 3 x 25 mg indomethacin daily for 7 days prior to elective cholecystectomy while 20 received no treatment and served as controls. Bile and tissue samples from the gallbladder were obtained during cholecystectomy. Indomethacin tissue levels in the gallbladder mucosa, as assessed by HPLC, were 1.05 +/- 0.4 ng/mg wet weight, a concentration known to inhibit effectively cyclooxygenase activity. Nevertheless, no differences between the treated and untreated groups were found in the concentrations of biliary mucus glycoprotein (0.94 +/- 0.27 versus 0.93 +/- 0.32 mg/ml) or total protein (5.8 +/- 0.9 versus 6.4 +/- 1.3 mg/ml), cholesterol saturation (1.3 +/- 0.2 versus 1.5 +/- 0.2), or nucleation time (2.0 +/- 3.0 versus 1.5 +/- 2.0 days). However, biliary viscosity, measured using a low-shear rotation viscosimeter, was significantly lower in patients receiving indomethacin treatment (2.9 +/- 0.6 versus 5.6 +/- 1.2 mPa.s; P < 0.02). In conclusion, in man oral indomethacin decreases bile viscosity without alteration of bile lithogenicity or biliary mucus glycoprotein content.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholesterol cholelithiasis in the prairie dog: role of mucin and nonmucin glycoproteins

The aims of this study were to examine the effect of exogenous prostaglandin on mucin secretion and to determine the role of nonmucin glycoproteins on gallstone formation in the prairie dog model of cholesterol cholelithiasis. The concentration of total glycoprotein and nonmucin glycoproteins was measured in gallbladder bile from four groups of prairie dogs fed a control diet or a diet supplemented with 1.2% cholesterol with or without simultaneous subcutaneous administration of prostaglandin E1. Cholesterol feeding resulted in an increased concentration of concanavalin-A binding-proteins in gallbladder bile associated with an increase in pronucleating activity in vitro. Treatment with prostaglandin E1 and cholesterol feeding was associated with a significant increase in the incidence of cholesterol gallstone formation. Prostaglandin E1 treatment in the cholesterol-fed animals increased biliary concentrations of total glycoprotein and concanavalin-A-binding glycoproteins. Therefore the increased biliary glycoprotein level in cholesterol-fed, prostaglandin E1-treated prairie dogs, which reflects higher levels of mucin and nonmucin glycoproteins, appears to be an important factor in gallstone formation.