Gallbladder muscle dysfunction in patients with chronic acalculous disease

Functional gastrointestinal disorders. Overlap syndrome Clinical guidelines of the Russian Scientific Medical Society of Internal Medicine and Gastroenterological Scientific Society of Russia

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Constitutive law of healthy gallbladder walls in passive state with damage effect

Biomechanical properties of human gallbladder (GB) wall in passive state can be valuable to diagnosis of GB diseases. In the article, an approach for identifying damage effect in GB walls during uniaxial tensile test was proposed and a strain energy function with the damage effect was devised as a constitutive law phenomenologically. Scalar damage variables were introduced respectively into the matrix and two families of fibres to assess the damage degree in GB walls. The parameters in the constitutive law with the damage effect were determined with a custom MATLAB code based on two sets of existing uniaxial tensile test data on human and porcine GB walls in passive state. It turned out that the uniaxial tensile test data for GB walls could not be fitted properly by using the existing strain energy function without the damage effect, but could be done by means of the proposed strain energy function with the damage effect involved. The stresses and Young moduli developed in two families of fibres were more than thousands higher than the stresses and Young's moduli in the matrix. According to the damage variables estimated, the damage effect occurred in two families of fibres only. Once the damage occurs, the value of the strain energy function will decrease. The proposed constitutive laws are meaningful for finite element analysis on human GB walls.

Fatty meal sonography comparing coconut oil and chocolate bar with full-fat yoghurt as cholecystagogues for gallbladder ejection fractions

Background

The authors compared the effectiveness of a chocolate bar and full-fat yoghurt combination to coconut oil in determining the gallbladder ejection fraction (GBEF). The clinical motive was functional gallbladder disorder (FGD) which has the clinical picture of symptomatic gallstones but without gallstones. Functional gallbladder disorder has a decreased GBEF of less than 35%. Gallbladder ejection fraction can be calculated by ultrasound, using cholecystokinin (CCK) as a stimulant for gallbladder contraction. Cholecystokinin is not available in South Africa, and the researchers compared a 60 g Snickers chocolate bar with 200 g full-fat yoghurt, against the theoretically superior coconut oil.

Objectives

To determine the efficacy of coconut oil versus chocolate bar and 200 g full-fat yoghurt combination in performing sonographic GBEFs.

Method

This was a randomised clinical experiment, before and after crossover trial. The three experimental components of the study included 15 g coconut oil, 20 g coconut oil and a standard fatty meal consisting of 60 g Snickers bar and 200 g full-fat yoghurt.

Results

The GBEF for the chocolate bar and yoghurt combination was the highest (62.84%). The GBEF for 20 g of coconut oil was 23.47% and for 15 g of coconut oil was 5.11%. There was a statistically significant difference between the chocolate and yoghurt combination and the 20 g coconut oil, as well as the chocolate yoghurt combination and the 15 g coconut oil, both with a p-value of < 0.0001. No statistically significant difference was found between the 20 g and 15 g coconut oil.

Conclusions

The 60 g Snickers chocolate bar and 200 g full-fat yoghurt combination was superior to the coconut oil. The authors advocate using the chocolate and yoghurt fatty meal oral stimulant to determine GBEF.

An update on the pathogenesis of cholesterol gallstone disease

PURPOSE OF REVIEW

Gallstone disease is a major epidemiologic and economic burden worldwide, and the most frequent form is cholesterol gallstone disease.

RECENT FINDINGS

Major pathogenetic factors for cholesterol gallstones include a genetic background, hepatic hypersecretion of cholesterol, and supersaturated bile which give life to precipitating cholesterol crystals that accumulate and grow in a sluggish gallbladder. Additional factors include mucin and inflammatory changes in the gallbladder, slow intestinal motility, increased intestinal absorption of cholesterol, and altered gut microbiota. Mechanisms of disease are linked with insulin resistance, obesity, the metabolic syndrome, and type 2 diabetes. The role of nuclear receptors, signaling pathways, gut microbiota, and epigenome are being actively investigated.

SUMMARY

Ongoing research on cholesterol gallstone disease is intensively investigating several pathogenic mechanisms, associated metabolic disorders, new therapeutic approaches, and novel strategies for primary prevention, including lifestyles.

Recent advances in understanding and managing cholesterol gallstones

The high prevalence of cholesterol gallstones, the availability of new information about pathogenesis, and the relevant health costs due to the management of cholelithiasis in both children and adults contribute to a growing interest in this disease. From an epidemiologic point of view, the risk of gallstones has been associated with higher risk of incident ischemic heart disease, total mortality, and disease-specific mortality (including cancer) independently from the presence of traditional risk factors such as body weight, lifestyle, diabetes, and dyslipidemia. This evidence points to the existence of complex pathogenic pathways linking the occurrence of gallstones to altered systemic homeostasis involving multiple organs and dynamics. In fact, the formation of gallstones is secondary to local factors strictly dependent on the gallbladder (that is, impaired smooth muscle function, wall inflammation, and intraluminal mucin accumulation) and bile (that is, supersaturation in cholesterol and precipitation of solid crystals) but also to "extra-gallbladder" features such as gene polymorphism, epigenetic factors, expression and activity of nuclear receptors, hormonal factors (in particular, insulin resistance), multi-level alterations in cholesterol metabolism, altered intestinal motility, and variations in gut microbiota. Of note, the majority of these factors are potentially manageable. Thus, cholelithiasis appears as the expression of systemic unbalances that, besides the classic therapeutic approaches to patients with clinical evidence of symptomatic disease or complications (surgery and, in a small subgroup of subjects, oral litholysis with bile acids), could be managed with tools oriented to primary prevention (changes in diet and lifestyle and pharmacologic prevention in subgroups at high risk), and there could be relevant implications in reducing both prevalence and health costs.

Rome IV. Gallbladder and Sphincter of Oddi Disorders

The concept that motor disorders of the gallbladder, cystic duct and sphincter of Oddi can cause painful syndromes is attractive and popular, at least in the USA. However, the results of commonly performed ablative treatments (cholecystectomy and sphincterotomy) are not uniformly good. The predictive value of tests that are often used to diagnose dysfunction (dynamic gallbladder scintigraphy and sphincter manometry) is controversial. Evaluation and management of these patients is made difficult by the fluctuating symptoms and the placebo effect of invasive interventions. A recent stringent study has shown that sphincterotomy is no better than sham treatment in patients with post-cholecystectomy pain and little or no objective abnormalities on investigation, so that the old concept of sphincter of Oddi dysfunction (SOD) type III is discarded. ERCP approaches are no longer appropriate in that context. There is a pressing need for similar prospective studies to provide better guidance for clinicians dealing with these patients. We need to clarify the indications for cholecystectomy in patients with Functional Gallbladder Disorder (FGBD) and the relevance of sphincter dysfunction in patients with some evidence for biliary obstruction (previously SOD type II, now called "Functional Biliary Sphincter Disorder - FBSD") and with idiopathic acute recurrent pancreatitis.

The cholecystokinin-1 receptor antagonist devazepide increases cholesterol cholelithogenesis in mice

BACKGROUND

A defect in gallbladder contraction function plays a key role in the pathogenesis of gallstones. The cholecystokinin-1 receptor (CCK-1R) antagonists have been extensively investigated for their therapeutic effects on gastrointestinal and metabolic diseases in animal studies and clinical trials. However, it is still unknown whether they have a potential effect on gallstone formation.

DESIGN

To study whether the CCK-1R antagonists enhance cholelithogenesis, we investigated cholesterol crystallization, gallstone formation, hepatic lipid secretion, gallbladder emptying function and intestinal cholesterol absorption in male C57BL/6J mice treated by gavage with devazepide (4 mg/day/kg) or vehicle (as controls) twice per day and fed the lithogenic diet for 21 days.

RESULTS

During 21 days of feeding, oral administration of devazepide significantly accelerated cholesterol crystallization and crystal growth to microlithiasis, with 40% of mice forming gallstones, whereas only agglomerated cholesterol monohydrate crystals were found in mice receiving vehicle. Compared to the vehicle group, fasting and postprandial residual gallbladder volumes in response to the high-fat meal were significantly larger in the devazepide group during cholelithogenesis, showing reduced gallbladder emptying and bile stasis. Moreover, devazepide significantly increased hepatic secretion of biliary cholesterol, but not phospholipids or bile salts. The percentage of intestinal cholesterol absorption was higher in devazepide-treated mice, increasing the bioavailability of chylomicron-derived cholesterol in the liver for biliary hypersecretion into bile. These abnormalities induced supersaturated bile and rapid cholesterol crystallization.

CONCLUSIONS

The potent CCK-1R antagonist devazepide increases susceptibility to gallstone formation by impairing gallbladder emptying function, disrupting biliary cholesterol metabolism and enhancing intestinal cholesterol absorption in mice.

Gallbladder dysfunction: how much longer will it be controversial?

BACKGROUND

Motility disorders of the biliary tree [biliary dyskinesia, including both gallbladder dysfunction (GBD), and sphincter of Oddi dysfunction] are difficult to diagnose and to treat.

SUMMARY

There is controversy in the literature in particular regarding the criteria that should be used to select patients for cholecystectomy (CCY) in cases of suspected GBD. The current review covers the history, diagnosis, and treatment of GBD. Key Messages: Only >85% of patients with suspected GBD have relief following CCY, a much lower rate than the nearly 100% success rate following CCY for gallstone disease. Unfortunately, the literature is lacking, and there are no universally agreed-upon criteria for selecting which patients to refer for operation, although cholecystokinin (CCK)-enhanced hepatobiliary iminodiacetic acid scan is often used, with emphasis on an abnormally low gallbladder ejection fraction or pain reproduction at CCK administration. There is a clear need for large, well-designed, more definitive, prospective studies to better identify the indications for and efficacy of CCY in cases of GBD.

Pain provocation and low gallbladder ejection fraction with CCK cholescintigraphy are not predictive of chronic acalculous gallbladder disease symptom relief after cholecystectomy

INTRODUCTION

Chronic acalculous gallbladder disease (CAGD) falls within the spectrum of diseases associated with gallbladder dysmotility. Cholecystokinin-cholescintigraphy (CCK-CS) has been used to evaluate for CAGD, with a gallbladder ejection fraction (GBEF) of <35 % being indicative of gallbladder dysfunction. The reproduction of biliary colic upon administration of CCK has been cited as indicative of CAGD. Our purpose was to determine whether low GBEF or reproduction of pain during CCK-CS was predictor of surgical outcomes related to resolution of symptoms or as a correlate to gallbladder pathology.

METHODS

A retrospective review of patients was performed to evaluate adults with a diagnosis of CAGD who underwent CCK-CS prior to surgical intervention. CPT and ICD-9 coding queries were used to identify the patient population. Patients with cholelithiasis were excluded.

RESULTS

Sixty-four patients met inclusion criteria. Two patients were lost to follow-up and were excluded. During CCK-CS, 41 patients (66 %) reported symptoms similar to their presenting complaint. Twenty-one patients reported no symptoms with CCK-CS. There was no significant relationship between gallbladder pathology and either GBEF or reproduction of symptoms with CCK-CS (p = 0.14). About 81 % of patients (n = 50) had relief of symptoms following cholecystectomy. Sixty-six percentage of patients (n = 33) with long-term symptom relief after cholecystectomy had reproduction of symptoms with CCK-CS. Nineteen percentage of all patients (n = 12) had long-term symptom recurrence despite surgery. Eight of these patients (66 %) had symptom reproduction with CCK-CS. There was no significant correlation with either the GBEF or symptoms reproduction with CCK-CS as a predictor of postoperative outcome (p = 0.12).

CONCLUSION

Provocation of pain by CCK-CS and low GBEF are unreliable predictors of postoperative relief of symptoms following cholecystectomy for biliary dyskinesia or chronic acalculous gallbladder disease.

Membrane cholesterol affects stimulus-activity coupling in type 1, but not type 2, CCK receptors: use of cell lines with elevated cholesterol

The lipid microenvironment of membrane proteins can affect their structure, function, and regulation. We recently described differential effects of acute modification of membrane cholesterol on the function of type 1 and 2 cholecystokinin (CCK) receptors. We now explore the regulatory impact of chronic cholesterol modification on these receptors using novel receptor-bearing cell lines with elevated membrane cholesterol. Stable CCK1R and CCK2R expression was established in clonal lines of 25RA cells having gain-of-function in SCAP [sterol regulatory element binding protein (SREBP) cleavage-activating protein] and SRD15 cells having deficiencies in Insig-1 and Insig-2 enzymes affecting HMG CoA reductase and SREBP. Increased cholesterol in the plasma membrane of these cells was directly demonstrated, and receptor binding and signaling characteristics were shown to reflect predicted effects on receptor function. In both environments, both types of CCK receptors were internalized and recycled normally in response to agonist occupation. No differences in receptor distribution within the membrane were appreciated at the light microscopic level in these CHO-derived cell lines. Fluorescence anisotropy was studied for these receptors occupied by fluorescent agonist and antagonist, as well as when tagged with YFP. These studies demonstrated increased anisotropy of the agonist ligand occupying the active state of the CCK1R in a cholesterol-enriched environment, mimicking fluorescence of the uncoupled, inactive state of this receptor, while there was no effect of increasing cholesterol on fluorescence at the CCK2R. These cell lines should be quite useful for examining the functional characteristics of potential drugs that might be used in an abnormal lipid environment.

Disruption of gallbladder smooth muscle function is an early feature in the development of cholesterol gallstone disease

BACKGROUND; Decreased gallbladder smooth muscle (GBSM) contractility is a hallmark of cholesterol gallstone disease, but the interrelationship between lithogenicity, biliary stasis, and inflammation are poorly understood. We studied a mouse model of gallstone disease to evaluate the development of GBSM dysfunction relative to changes in bile composition and the onset of sterile cholecystitis.

METHODS

BALB/cJ mice were fed a lithogenic diet for up to 8 weeks, and tension generated by gallbladder muscle strips was measured. Smooth muscle Ca(2+) transients were imaged in intact gallbladder.

KEY RESULTS

Lipid composition of bile was altered lithogenically as early as 1 week, with increased hydrophobicity and cholesterol saturation indexes; however, inflammation was not detectable until the fourth week. Agonist-induced contractility was reduced from weeks 2 through 8. GBSM normally exhibits rhythmic synchronized Ca(2+) flashes, and their frequency is increased by carbachol (3 μm). After 1 week, lithogenic diet-fed mice exhibited disrupted Ca(2+) flash activity, manifesting as clustered flashes, asynchronous flashes, or prolonged quiescent periods. These changes could lead to a depletion of intracellular Ca(2+) stores, which are required for agonist-induced contraction, and diminished basal tone of the organ. Responsiveness of Ca(2+) transients to carbachol was reduced in mice on the lithogenic diet, particularly after 4-8 weeks, concomitant with appearance of mucosal inflammatory changes.

CONCLUSIONS & INFERENCES

These observations demonstrate that GBSM dysfunction is an early event in the progression of cholesterol gallstone disease and that it precedes mucosal inflammation.

Sensitivity of cholecystokinin receptors to membrane cholesterol content

Cholesterol represents a structurally and functionally important component of the eukaryotic cell membrane, where it increases lipid order, affects permeability, and influences the lateral mobility and conformation of membrane proteins. Several G protein-coupled receptors have been shown to be affected by the cholesterol content of the membrane, with functional impact on their ligand binding and signal transduction characteristics. The effects of cholesterol can be mediated directly by specific molecular interactions with the receptor and/or indirectly by altering the physical properties of the membrane. This review focuses on the importance and differential effects of membrane cholesterol on the activity of cholecystokinin (CCK) receptors. The type 1 CCK receptor is quite sensitive to its cholesterol environment, while the type 2 CCK receptor is not. The possible structural basis for this differential impact is explored and the implications of pathological states, such as metabolic syndrome, in which membrane cholesterol may be increased and CCK1R function may be abnormal are discussed. This is believed to have substantial potential importance for the development of drugs targeting the CCK receptor.

Differential sensitivity of types 1 and 2 cholecystokinin receptors to membrane cholesterol

Recent studies indicate that membrane cholesterol can associate with G protein-coupled receptors (GPCRs) and affect their function. Previously, we reported that manipulation of membrane cholesterol affects ligand binding and signal transduction of the type 1 cholecystokinin receptor (CCK1R), a Class A GPCR. We now demonstrate that the closely related type 2 cholecystokinin receptor (CCK2R) does not share this cholesterol sensitivity. The sequences of both receptors reveal almost identical cholesterol interaction motifs in analogous locations in transmembrane segments two, three, four, and five. The disparity in cholesterol sensitivity between these receptors, despite their close structural relationship, provides a unique opportunity to define the possible structural basis of cholesterol sensitivity of CCK1R. To evaluate the relative contributions of different regions of CCK1R to cholesterol sensitivity, we performed ligand binding studies and biological activity assays of wild-type and CCK2R/CCK1R chimeric receptor-bearing Chinese hamster ovary cells after manipulation of membrane cholesterol. We also extended these studies to site-directed mutations within the cholesterol interaction motifs. The results contribute to a better understanding of the structural requirements for cholesterol sensitivity in CCK1R and provides insight into the function of other cholesterol-sensitive Class A GPCRs.

Gallbladder dyskinesia

The most appropriate means to diagnose and manage patients with suspected gallbladder dyskinesia remain contentious. A major problem relates to difficulties in clearly identifying the features that characterize biliary-like pain. Conflicting reports in the literature regarding whether symptoms alone are reliable predictors of pain relief after cholecystectomy in patients with suspected gallbladder dysfunction underscore the perceived need by clinicians for a reliable test to help confirm a clinical suspicion of gallbladder dysfunction before cholecystectomy. Most studies report use of cholecystokinin-cholescintigraphy (CCK-CS) with calculation of gallbladder ejection fraction in predicting symptom outcome after cholecystectomy in patients with suspected gallbladder dyskinesia. However, quality evidence is lacking, thereby precluding a definitive recommendation regarding its use. Nevertheless, CCK-CS may be useful when performed using a slow infusion of CCK in a well-selected patient population. Based on our clinical experience and interpretation of the literature, we currently suggest consideration of cholecystectomy to our patients based on high clinical suspicion. This is performed after adequate follow-up with trials of pharmacologic therapies and exclusion of other disease entities and counseling the patient on postoperative expectations. Clearly, a large, prospective, controlled study is needed with patients meeting the Rome definition of gallbladder dyskinesia, randomized to surgery or no surgery, and using standardized CCK-CS methods and outcome measures with long-term follow-up. This study would help us better understand the pathophysiology and optimal management of this clinically challenging condition.

Effects of cholesterol on CCK-1 receptors and caveolin-3 proteins recycling in human gallbladder muscle

The contraction of gallbladders (GBs) with cholesterol stones is impaired due to high cholesterol concentrations in caveolae compared with GBs with pigment stones. The reduced contraction is caused by a lower cholecystokinin (CCK)-8 binding to CCK-1 receptors (CCK-1R) due to caveolar sequestration of receptors. We aimed to examine the mechanism of cholesterol-induced sequestration of receptors. Muscle cells from human and guinea pig GBs were studied. Antibodies were used to examine CCK-1R, antigens of early and recycling endosomes, and total (CAV-3) and phosphorylated caveolar-3 protein (pCAV-3) by Western blots. Contraction was measured in muscle cells transfected with CAV3 mRNA or clathrin heavy-chain small-interfering RNA (siRNA). CCK-1R returned back to the bulk plasma membrane (PM) 30 min after CCK-8 recycled by endosomes, peaking at 5 min in early endosomes and at 20 min in recycling endosomes. Pretreatment with cholesterol-rich liposomes inhibited the transfer of CCK-1R and of CAV-3 in the endosomes by blocking CAV-3 phosphorylation. 4-Amino-5-(4-chloro-phenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (inhibitor of tyrosine kinase) reproduced these effects by blocking pCAV-3 formation, increasing CAV-3 and CCK-1R sequestration in the caveolae and impairing CCK-8-induced contraction. CAV-3 siRNA reduced CAV-3 protein expression, decreased CCK-8-induced contraction, and accumulated CCK-1R in the caveolae. Abnormal concentrations of caveolar cholesterol had no effect on met-enkephalin that stimulates a delta-opioid receptor that internalizes through clathrin. We found that impaired muscle contraction in GBs with cholesterol stones is due to high caveolar levels of cholesterol that inhibits pCAV-3 generation. Caveolar cholesterol increases the caveolar sequestration of CAV-3 and CCK-1R caused by their reduced recycling to the PM.

Gallbladder imaging

The treatment of gallbladder disease has been revolutionized by improvements in laparoscopic surgery as well as endoscopic and radiologic interventional techniques. Therapeutic success is dependent on accurate radiologic assessment of gallbladder pathology. This article describes recent technical advances in ultrasonography, multidetector computed tomography, magnetic resonance imaging, positron emission tomography, and scintigraphy, which have significantly improved the accuracy of noninvasive imaging of benign and malignant gallbladder disease. The imaging findings of common gallbladder disorders are presented, and the role of each of the imaging modalities is placed in perspective for optimizing patient management.

Functional gallbladder disorder: gallbladder dyskinesia

Functional gallbladder disorder, commonly referred to as gallbladder dyskinesia, is characterized by the occurrence of abdominal pain resembling gallbladder pain but in the absence of gallstones. The diagnosis and management of this condition can be confusing even for the most astute clinician. The aim of this article is to clarify the identification and management of patients with suspected functional gallbladder disorder.

Evaluation and management of functional biliary pain in patients with an intact gallbladder

The diagnosis and management of suspected functional biliary pain in patients with an intact gallbladder remains contentious. Major issues include the lack of a clear definition of what constitutes biliary pain, a poor understanding of its natural history and pathophysiology, and the all too common scenario of the patient who has persistent pain despite surgical removal of the gallbladder. As a consequence, symptoms alone have generally been considered to be unreliable in the diagnosis of gallbladder dysfunction, and this has led to a search for a reliable test to help confirm a clinical suspicion of gallbladder dysfunction prior to the definitive treatment, cholecystectomy. At present, cholecystokinin-cholescintigraphy with a calculation of the gallbladder ejection fraction is the most commonly used test; however, its utility in predicting symptom outcome after cholecystectomy has been questioned. The use of cholecystokinin-cholescintigraphy to determine the appropriateness for cholecystectomy appears to be most useful when performed using a slow infusion of cholecystokinin in a well-selected patient population. However, for reasons explained herein, consideration of cholecystectomy on the basis of high clinical suspicion after adequate follow-up with trials of pharmacological therapies and exclusion of other disease entities, together with counseling the patient on postoperative expectations, may be a reasonable alternative.

High levels of caveolar cholesterol inhibit progesterone-induced genomic actions in human and guinea pig gallbladder muscle

Gallbladder disease is prevalent during pregnancy. It has been suggested that this complication of pregnancy is attributable to increased bile cholesterol (Ch) induced by estrogens and to gallbladder hypomotility caused by increasing levels of progesterone (P4). Studies on nonpregnant gallbladders have shown that increased levels of bile Ch contribute to both gallstone formation and bile stasis. These studies investigated the effects of high levels of plasma membrane Ch on P4 on gallbladder muscle cells from human and guinea pigs. Contraction was studied in intact and permeabilized muscle cells. G proteins were determined by Western blot, and 3H-P4 incorporation by muscle cells was measured in the beta-scintillation counter. High levels of caveolar Ch blocked the effects induced by P4 treatment for 6 h. They suppressed the expected P4 inhibition of GTP-gammaS (a G protein activator)-induced contraction and changes in G proteins by downregulating Gi3 and upregulating Gs protein levels. Ch inhibited these P4 actions at the caveolar 3 (CAV-3) level, since the P4 effects were antagonized by treatment with CAV-3 antibody, by reducing CAV-3 expression through CAV-3 siRNA. CAV-3 antibody and siRNA reduced caveolar Ch levels. High caveolar levels of Ch and CAV-3 antibody blocked the incorporation of 3H-P4 into caveolae. Treatment with GDP-betaS (a G protein antagonist) had no effect on P4 actions. High caveolar Ch levels blocked the P4 effects on muscle contraction and G protein changes probably because both Ch and P4 require CAV-3 proteins for their transport across the plasma membrane.

Usefulness of fatty meal-stimulated cholescintigraphy in the diagnosis and treatment of chronic acalculous cholecystitis

OBJECTIVE

Fatty meal cholescintigraphy (fatty meal CS) is a potential physiologic alternative for cholecystokinin (CCK) CS in the diagnosis and treatment of chronic acalculous cholecystitis (CAC). However, there are limited data in the literature to support this assumption. Our objective was to determine the usefulness of fatty meal CS in the diagnosis and treatment of CAC.

METHODS

We retrospectively reviewed the medical records of 198 patients who had undergone fatty meal CS for presumed CAC. Data retrieved focused on symptom improvement following management. Gallbladder ejection fraction (GBEF) of 50% or less was considered abnormal. Patients were divided into groups on the basis of test results and management.

RESULTS

In group 1a, patients with low GBEF and cholecystectomy, 88% (54 of 61) reported symptom improvement, whereas the remaining 12% (7 of 61) retained their symptoms. Group 1b consisted of patients with low GBEF and who were managed medically. Persistence of symptoms was noted in 76% (32 of 42) of patients, whereas the remaining 24% (10 of 42) had symptom improvement. Group 2 consisted of patients with normal GBEF. Follow-up showed that 60% (47 of 78) of patients had symptom improvement either spontaneously or on medical treatment, whereas the remaining 40% (31 of 78) retained their symptoms.

CONCLUSIONS

Fatty meal CS is a very useful technique in the diagnosis of CAC. It predicts a good surgical outcome once GBEF is low in patients with high pre-test probability for CAC. Moreover, fatty meal CS may be a good alternative to CCK CS.

Coordinate regulation of gallbladder motor function in the gut-liver axis

Gallstones are one of the most common digestive diseases with an estimated prevalence of 10%-15% in adults living in the western world, where cholesterol-enriched gallstones represent 75%-80% of all gallstones. In cholesterol gallstone disease, the gallbladder becomes the target organ of a complex metabolic disease. Indeed, a fine coordinated hepatobiliary and gastrointestinal function, including gallbladder motility in the fasting and postprandial state, is of crucial importance to prevent crystallization and precipitation of excess cholesterol in gallbladder bile. Also, gallbladder itself plays a physiopathological role in biliary lipid absorption. Here, we present a comprehensive view on the regulation of gallbladder motor function by focusing on recent discoveries in animal and human studies, and we discuss the role of the gallbladder in the pathogenesis of gallstone formation.

Reactive oxygen species are messengers in maintenance of human and guinea pig gallbladder tonic contraction

The tonic contraction of human and guinea pig gallbladder (GB) is dependent on basal levels of PGE(2) and thromboxane A(2) (TxA(2)). The pathway involved in the genesis of these prostaglandins has not been elucidated. We aimed to examine the source of reactive oxygen species (ROS) and whether they contribute to the genesis of GB tonic contraction by generating basal prostaglandin levels. Tonic contraction was studied in human and guinea pig GB muscle strips treated with ROS scavengers (Tiron and catalase), apocynin (an inhibitor of NADPH oxidase), and NOX-1 small interference RNA (siRNA). The subunits of NADPH oxidase and their functional roles were determined with specific antibodies in GB muscle cells. ROS scavengers reduced the GB tonic contraction and H(2)O(2) and PGE(2) levels. Apocynin also inhibited the tonic contraction. Antibodies against subunits of NADPH oxidase present in GB muscle cells lowered H(2)O(2) and PGE(2) levels. NOX-1 siRNA transfection reduced the tonic contraction, NOX-1 expression, and levels of H(2)O(2) and PGE(2). Tiron and apocynin inhibited the expected increase in tension and H(2)O(2) levels induced by stretching of muscle strips. H(2)O(2) increased the levels of PGE(2) and TxA(2) by increasing platelet-activating factor-like lipids that phosphorylate p38 and cPLA(2) sequentially. H(2)O(2) generated by NADPH oxidase participates in a signal transduction pathway that maintains the GB tonic contraction by activating PAF, p38, and cPLA(2) to generate prostaglandins.

Cholecystosteatosis: an explanation for increased cholecystectomy rates

INTRODUCTION

Over the past decade, obesity has become epidemic, and the number of cholecystectomies as well as the percentage with acalculous cholecystitis have increased. We have recently reported that congenitally obese mice and lean mice fed a high fat diet have increased gallbladder wall lipids and poor gallbladder emptying. Therefore, we tested the hypothesis that compared to patients with a normal gallbladder, patients with both acalculous and calculous cholecystitis would have increased gallbladder wall fat.

METHODS

Sixteen patients who underwent cholecystectomy for acalculous cholecystitis were identified. Sixteen nondiseased controls who underwent incidental cholecystectomy during surgery for liver or pancreatic disease and 16 diseased controls whose gallbladder was removed for chronic calculous cholecystitis were chosen to match the acalculous patients for gender and Body Mass Index. Pathology specimens were reviewed in a blinded fashion for gallbladder wall fat, thickness, and inflammation.

RESULTS

Acalculous cholecystitis patients were younger (p < 0.01) than nondiseased or diseased controls. Gallbladder wall fat was significantly increased (p < 0.02) in the acalculous and calculous cholecystitis patients compared to the nondiseased controls. Gallbladder wall thickness (p < 0.02) and inflammatory score (p < 0.01) were highest in the calculous cholecystitis patients.

CONCLUSIONS

These data suggest that compared to nondiseased controls, (1) patients with acalculous cholecystitis are younger and have increased gallbladder fat and (2) patients with calculous cholecystitis have increased gallbladder fat and inflammation. We conclude that increased gallbladder fat may lead to poor gallbladder emptying and biliary symptoms. Thus, cholecystosteatosis may explain, in part, the increased need for cholecystectomy and the higher percentage of these patients with acalculous cholecystitis.

Role of caveolae in the pathogenesis of cholesterol-induced gallbladder muscle hypomotility

Muscle cells from human gallbladders (GB) with cholesterol stones (ChS) exhibit a defective contraction, excess cholesterol (Ch) in the plasma membrane, and lower binding of CCK-1 receptors. These abnormalities improved after muscle cells were incubated with Ch-free liposomes that remove the excess Ch from the plasma membrane. The present studies were designed to investigate the role of caveolin-3 proteins (Cav-3) in the pathogenesis of these abnormalities. Muscle cells from GB with ChS exhibit higher Ch levels in the plasma membrane that were mostly localized in caveolae and associated with parallel increases in the expression of Cav-3 in the caveolae compared with that in GB with pigment stones (PS). The overall number of CCK-1 receptors in the plasma membrane was not different between muscle cells from GB with ChS and PS, but they were increased in the caveolae in muscle cells from GB with ChS. Treatment of muscle cells from GB with ChS with a Galpha(i3) protein fragment increased the total binding of CCK-1 receptors (from 8.3 to 11.2%) and muscle contraction induced by CCK-8 (from 11.2 to 17.3% shortening). However, Galpha(q/11) protein fragment had no such effect. Moreover, neither fragment had any effect on muscle cells from GB with PS. We conclude that the defective contraction of muscle cells with excessive Ch levels in the plasma membrane is due to an increased expression of Cav-3 that results in the sequestration of CCK-1 receptors in the caveolae, probably by inhibiting the functions of Galpha(i3) proteins.

Prostaglandins mediate tonic contraction of the guinea pig and human gallbladder

The gallbladder (GB) maintains tonic contraction modulated by neurohormonal inputs but generated by myogenic mechanisms. The aim of these studies was to examine the role of prostaglandins in the genesis of GB myogenic tension. Muscle strips and cells were treated with prostaglandin agonists, antagonists, cyclooxygenase (COX) inhibitors, and small interference RNA (siRNA). The results show that PGE2, thromboxane A2 (TxA2), and PGF(2alpha) cause a dose-dependent contraction of muscle strips and cells. However, only TxA2 and PGE2 (E prostanoid 1 receptor type) antagonists induced a dose-dependent decrease in tonic tension. A COX-1 inhibitor decreased partially the tonic contraction and TxB2 (TxA2 stable metabolite) levels; a COX-2 inhibitor lowered the tonic contraction partially and reduced PGE2 levels. Both inhibitors and the nonselective COX inhibitor indomethacin abolished the tonic contraction. Transfection of human GB muscle strips with COX-1 siRNA partially lowered the tonic contraction and reduced COX-1 protein expression and TxB2 levels; COX-2 siRNA also partially reduced the tonic contraction, the protein expression of COX-2, and PGE2. Stretching muscle strips by 1, 2, 3, and 4 g increased the active tension, TxB2, and PGE2 levels; a COX-1 inhibitor prevented the increase in tension and TxB2; and a COX-2 inhibitor inhibited the expected rise in tonic contraction and PGE2. Indomethacin blocked the rise in tension and TxB2 and PGE2 levels. We conclude that PGE2 generated by COX-2 and TxA2 generated by COX-1 contributes to the maintenance of GB tonic contraction and that variations in tonic contraction are associated with concomitant changes in PGE2 and TxA2 levels.

Role of CCK/gastrin receptors in gastrointestinal/metabolic diseases and results of human studies using gastrin/CCK receptor agonists/antagonists in these diseases

In this paper, the established and possible roles of CCK1 and CCK2 receptors in gastrointestinal (GI) and metabolic diseases are reviewed and available results from human agonist/antagonist studies are discussed. While there is evidence for the involvement of CCK1R in numerous diseases including pancreatic disorders, motility disorders, tumor growth, regulation of satiety and a number of CCK-deficient states, the role of CCK1R in these conditions is not clearly defined. There are encouraging data from several clinical studies of CCK1R antagonists in some of these conditions, but their role as therapeutic agents remains unclear. The role of CCK2R in physiological (atrophic gastritis, pernicious anemia) and pathological (Zollinger-Ellison syndrome) hypergastrinemic states, its effects on the gastric mucosa (ECL cell hyperplasia, carcinoids, parietal cell mass) and its role in acid-peptic disorders are clearly defined. Furthermore, recent studies point to a possible role for CCK2R in a number of GI malignancies. Current data from human studies of CCK2R antagonists are presented and their potential role in the treatment of these conditions reviewed. Furthermore, the role of CCK2 receptors as targets for medical imaging is discussed.

Cholecystokinin and gastrin receptors

Cholecystokinin and gastrin receptors (CCK1R and CCK2R) are G protein-coupled receptors that have been the subject of intensive research in the last 10 years with corresponding advances in the understanding of their functioning and physiology. In this review, we first describe general properties of the receptors, such as the different signaling pathways used to exert short- and long-term effects and the structural data that explain their binding properties, activation, and regulation. We then focus on peripheral cholecystokinin receptors by describing their tissue distribution and physiological actions. Finally, pathophysiological peripheral actions of cholecystokinin receptors and their relevance in clinical disorders are reviewed.

Functional gallbladder and sphincter of oddi disorders

The functional disorder of the gallbladder (GB) is a motility disorder caused initially either by metabolic abnormalities or by a primary motility alteration. The functional disorders of the sphincter of Oddi (SO) encompass motor abnormalities of either the biliary or the pancreatic SO. Dysfunction of the GB and/or biliary SO produce similar patterns of pain. The pain caused by a dysfunction of the pancreatic SO can be similar to that of acute pancreatitis. The symptom-based diagnostic criteria of motility dysfunction of the GB and biliary SO are episodes of moderate to severe steady pain located in the epigastrium and right upper abdominal quadrant that last at least 30 minutes. GB motility disorder is suspected after gallstones and other structural abnormalities have been excluded. This diagnosis should then be confirmed by a decreased GB ejection fraction induced by cholecystokinin at cholescintigraphy and after disappearance of the recurrent biliary pain after cholecystectomy. Symptoms of biliary SO dysfunction may be accompanied by features of transient biliary obstruction, and those of pancreatic SO dysfunction are associated with elevation of pancreatic enzymes and even pancreatitis. Biliary-type SO dysfunction is more frequently recognized in postcholecystectomy patients. SO manometry is valuable to select patients with sphincter dysfunction; however, because of the high incidence of complications, these patients should be referred to an expert unit for such assessment. Thus invasive tests should be performed only in the presence of compelling clinical evidence and after noninvasive testing has yielded negative findings. The committee recommends that division of the biliary or pancreatic sphincters only be considered when the patient has severe symptoms, meets the required criteria, and other diagnoses are excluded.

Short-term ursodeoxycholic acid treatment improves gallbladder bile turnover in gallstone patients: a randomized trial

Ursodeoxycholic acid (UDCA) prevents in vitro gallbladder (GB) muscle damage caused by acute cholecystitis and reduces risk of biliary pain and complications in gallstone (GS) patients. These effects could be partially explained by the improved GB bile turnover.

OBJECTIVES

To assess the effect of short-term UDCA treatment on GB motility and bile turnover.

METHODS

Ultrasonographic (US) assessment of GB volumes was performed in 16 GS patients, in the postprandial phase, for 90 min with a time sampling of 1 min, before and after 30 days of UDCA (10 mg kg(-1) die(-1)) or placebo, randomly assigned. US data were analysed with statistical tools and with computer fluido-dynamic (CFD) software Fluent(TM) to simulate GB bile flow.

RESULTS

After therapy, fasting volume (FV) increased from 21.6 +/- 9 to 28.2 +/- 12 mL (p < 0.001) while the ejection fraction (EF) remained unchanged (44.5 +/- 17% vs 45.1 +/- 20%; p: ns). Volumes before and after treatment were poorly correlated (0.02 < r < 0.35), unlike those in placebo patients (r > 0.6). The average GB volume was increased in 7 out of 10 patients following UDCA (range 7-67%). CFD analysis supports the finding of improved bile flow after treatment.

CONCLUSIONS

Unlike results of conventional US parameters of GB motility, CFD analysis shows that UDCA improves GB bile turnover in GS patients.

Controversies concerning pathophysiology and management of acalculous biliary-type abdominal pain

Acalculous biliary-type abdominal pain is a commonly encountered clinical problem whose pathophysiology is unclear and evaluation and management are controversial. Cholecystokinin cholescintigraphy to measure the gallbladder ejection fraction (GEF) has been advocated as a criterion for cholecystectomy. However, there is no consensus regarding the dose and rate of infusion of cholecystokinin, both of which can alter the GEF, and the definition of an abnormal ejection fraction varies among studies. Many but not all studies have concluded that a low GEF predicts good outcomes after cholecystectomy, but most studies suffer from poor methodology and there is only one prospective randomized controlled trial. Also, some patients with a normal GEF have responded to cholecystectomy. Another controversial area has been the role of sphincter of Oddi dysfunction (SOD) in patients with biliary-type pain and gallbladder in situ. Some reports suggest an overlap between SOD and low GEF, although a causal relationship has not been established. Yet another subject of interest is the role of visceral hyperalgesia in patients with acalculous biliary-type pain. We have reviewed the relevant literature relating to these issues and have highlighted the controversial aspects. In the absence of high-quality studies, an evidence-based treatment algorithm is difficult to design but will be proposed. More prospective controlled trials are warranted to better define the appropriate evaluation and management of patients with this syndrome.

Functional biliary-type pain: update and controversies

Recurrent biliary-type abdominal pain is a perplexing clinical dilemma that occurs in patients with an acalculous gallbladder in situ or in patients who have undergone a previous cholecystectomy. The pathogenesis of functional biliary-type pain is often unclear; therefore, evaluation and management remain controversial. In patients with an acalculous gallbladder in situ, critical importance has been given to delayed gallbladder emptying using cholescintigraphy (CCK-CS) to determine if gallbladder dysfunction is present. However, several issues remain unresolved, including methodology, definition of delayed emptying, and the absence of high-quality studies to determine if CCK-CS can predict who will do well with cholecystectomy. In patients with previous cholecystectomy, the main area of controversy is the evaluation of patients with sphincter of Oddi Type III, including the role of endoscopic retrograde cholangiopancreatography with SO manometry and sphincterotomy in these patients. Suggested algorithms for management of both clinical scenarios are provided.

Impaired cytoprotective function of muscle in human gallbladders with cholesterol stones

Acute cholecystitis develops in gallbladders (GB) with excessive bile cholesterol (Ch). Increased membrane Ch content affects membrane function and may affect PGE(2) receptors involved in the cytoprotection against acute inflammation. This study was aimed at determining whether the cytoprotective response to PGE(2) is affected by lithogenic bile with Ch. Muscle cells from human GB with cholesterol stones (ChS) or pigment stones (PS) were obtained by enzymatic digestion. PGE(2) levels were measured by radioimmunoassay, and activities of superoxide dismutase (SOD) and catalase were assayed by spectrophotometry. The contraction in response to H(2)O(2) in muscle cells from PS was 14 +/- 0.3%, not different from normal controls, and decreased after the cells were incubated with Ch-rich liposomes (P < 0.05), which increase the Ch content in the plasma membranes. In muscle cells from GB with ChS, H(2)O(2)-induced contraction was only 9.2 +/- 1.3% and increased to 14 +/- 0.2% after Ch-free liposome treatment to remove Ch from the plasma membranes (P < 0.01). H(2)O(2) caused a similar increase in the levels of lipid peroxidation and PGE(2) content in muscle cells from GBs with ChS and PS. However, the activities of SOD and catalase were significantly lower in muscle cells from GBs with ChS compared with those with PS. The binding capacity of PGE(2) receptors was also significantly lower in muscle cells from GBs with ChS compared with those with PS. In conclusion, the cytoprotective response to reactive oxygen species is reduced in muscle cells from GBs with ChS despite a normal increase in the cellular levels of PGE(2). This impaired cytoprotective response may be due to a dysfunction of PGE(2) receptors with decreased binding capacity resulting from excessive Ch levels in the plasma membrane.

Transforming growth factor-beta pathway is activated in cholecystolithiasis

BACKGROUND

The etiopathogenesis of cholecystolithiasis is not well defined. Primary dysmotility of the organ, due to fibrosis of the gallbladder wall or muscular dysfunction, is suggested as a crucial factor. Transforming growth factor-beta (TGF-beta) and connective tissue growth factor (CTGF) are involved in several fibrotic disorders and play a critical role in fibrogenesis, thereby changing the physiological function of the organs. In the present study we analyzed the role of TGF-beta and its downstream target CTGF in patients with cholecystolithiasis.

METHODS

Gallbladders were obtained from 16 individuals undergoing surgery for symptomatic cholecystolithiasis. Normal human gallbladder tissue samples from five individuals without any history of gallbladder disease were obtained through an organ donor transplantation program. Northern blot analysis, in situ hybridization, and immunohistochemistry were used to analyze the expression of TGF-beta1 and CTGF in the gallbladder tissue samples.

RESULTS

By northern blot analysis there was an enhanced TGF-beta1 mRNA expression (eightfold increase; P < 0.04) in the cholecystolithiasis tissue samples in comparison with normal controls. There was also a concomitant increase in CTGF (41-fold increase; P < 0.01). By in situ hybridization and immunohistochemistry, CTGF mRNA was localized mainly in the mucosa layer, while intensive staining of the smooth muscle cells with TGF-beta1 and CTGF was observed. In addition, TGF-beta1 immunoreactivity was also localized in the fibroblasts and inflammatory cells. TGF-beta1 m-RNA levels showed a significant relationship with the degree of fibrosis in the tissue samples (P < 0.04, r = 0.5).

CONCLUSION

Our data indicate that TGF-beta and CTGF are involved in ultrastructural tissue changes in patients with cholecystolithiasis. Activation of the "TGF-beta pathway," predominantly in the remaining mucosa and submucosal layer, indicates that extracellular matrix (ECM) synthesis with subsequent gallbladder wall fibrosis is an important step in gallbladder dysfunction in this disorder.

Bethanechol provocation testing does not predict symptom relief after cholecystectomy for acalculous biliary pain

BACKGROUND

The currently accepted hypothesis to explain acalculous gallbladder pain is the lack of contractile co-ordination between the body and neck. We have previously shown that bethanechol, a muscarinic stimulant causes differential stimulation of these two regions.

AIM

To evaluate the reliability of bethanechol-induced gallbladder contraction in predicting symptom relief after cholecystectomy in patients with acalculous gallbladder disease.

METHODS

Fifty-one patients underwent a bethanechol provocation test together with serial ultrasound to determine gallbladder emptying. McGill pain questionnaires were completed, and patients positive for pain (bethanechol provocation test +ve) were offered cholecystectomy, and patients negative for pain (bethanechol provocation test -ve) were reassessed at 6 months and offered cholecystectomy if symptoms persisted. All patients answered pain questionnaires either 6 months after surgery or as follow-up.

RESULTS

There was no difference in the percentage of gallbladder emptying between the bethanechol provocation test +ve and bethanechol provocation test -ve groups. Fifty-three percent of bethanechol provocation test +ve patients and 54% of bethanechol provocation test -ve patients still remained symptomatic 6 months after surgery. Conclusion. Gallbladder pain provoked by bethanechol does not predict symptom relief after cholecystectomy.

Smooth muscle function and dysfunction in gallbladder disease

The gallbladder epithelium and smooth muscle layer are exposed to concentrated biliary solutes, including cholesterol and potentially toxic hydrophobic bile salts, which are able to influence muscle contraction. Physiologically, gallbladder tone is regulated by spontaneous muscle activity, hormones, and neurotransmitters released into the muscle from intrinsic neurons and extrinsic sympathetic nerves. Methods to explore gallbladder smooth muscle function in vitro include cholecystokinin (CCK) receptor-binding studies and contractility studies. In human and animal models, studies have focused on cellular and molecular events in health and disease, and in vitro findings mirror in vivo events. The interplay between contraction and relaxation of the gallbladder muscularis leads in vivo to appropriate gallbladder emptying and refilling during fasting and postprandially. Defective smooth muscle contractility and/or relaxation are found in cholesterol stone-containing gallbladders, featuring a type of gallbladder leiomyopathy; defects of CCKA receptors and signal transduction may coexist with abnormal responses to oxidative stress and inflammatory mediators. Abnormal smooth musculature contractility, impaired gallbladder motility, and increased stasis are key factors in the pathogenesis of cholesterol gallstones.

Does gallbladder ejection fraction predict outcome after cholecystectomy for suspected chronic acalculous gallbladder dysfunction? A systematic review

The clinical utility of cholecystokinin-cholescintigraphy with calculation of a gallbladder ejection fraction (GBEF) in patients with suspected chronic acalculous gallbladder dysfunction (CAGD) remains controversial. It was our aim to critically evaluate the literature on the utility of the GBEF to predict outcome of patients with suspected CAGD. We performed an electronic search of the MEDLINE database for articles published between 1980 and 2002 and a manual search of references from bibliographies of identified articles. Only articles in English that concerned adults were screened. Data extracted included both qualitative and quantitative data reported on the study groups, cholescintigraphic technique, interventions, treatment outcomes, and trial methodologic characteristics. Twenty-three publications met the inclusion criteria. All were considered of poor methodologic quality. All but three studies were retrospective case series, only one was randomized, and none were adequately blinded, used adequate controls, or enrolled a sufficient number of patients. Five studies used a cut-off value for an abnormal GBEF that was different than the value used by the others, one study did not provide a cut-off value, and several did not report details of the cholescintigraphic technique (namely, the rate of cholecystokinin infusion). Studies varied in their outcome measures and the criteria for success. The overall assessment of outcome in 19 studies concluded that calculation of a GBEF was useful in patients with suspected CAGD. The low methodologic quality of the studies precluded a meta-analysis approach to the data. Use of a calculated GBEF to diagnose and predict treatment outcome in suspected CAGD has not been adequately studied. Although most studies report utility of GBEF in predicting symptom outcome after cholecystectomy in patients with suspected CAGD, quality evidence is lacking, thereby precluding a definitive recommendation regarding its use. More high quality trials are needed.

Gallbladder motility and functional gastrointestinal disorders

Functional gastrointestinal disorders can be defined as 'a variable combination of chronic or recurrent gastrointestinal symptoms not explained by structural or biochemical abnormalities'. Motor disorders are considered to be one of the pathogenetic mechanisms of these symptoms; in fact, it has been hypothesized that the smooth muscle of the whole gastrointestinal tract could be involved. Gallbladder motility has been evaluated in patients with dysmotility-like dyspepsia, irritable bowel syndrome and biliary disorders without gallstones; results of these observations are often inconclusive, conflicting and not always useful from a clinical point of view. The aim of this review is to explore the relationship between gallbladder motility and functional gastrointestinal disorders from pathogenetic and physiopathological points of view, and also to define the possible impact of these observations on clinical practice.

Value of measuring gallbladder motility in clinical practice

Measurement of gallbladder motility is a powerful research tool, but its value in clinical practice is uncertain. Three main conditions have been investigated for potential clinical application of this measurement. The first potential application is for identification of patients at risk of recurrence following gallstone dissolution with medical therapy. Results in this clinical setting are disappointing due to the low positive predictive value for gallstone recurrence in sluggish gallbladder emptying. The second potential application is for identification of obese patients at risk of gallstone formation during rapid weight loss. In this condition, a high negative predictive value has been reported for a normal gallbladder emptying pattern. The third potential application is for patients with recurrent biliary colic and acalcolous gallbladder disease. The diagnostic value of a provocative test involving intravenous cholecystokinin injection as a method of identifying patients likely to benefit from cholecystectomy is uncertain, partly as a consequence of non-standardized methodology. The balance of evidence reported in this review suggests a low inherent value of measurement of gallbladder motility in clinical practice. Acalcolous gallbladder disease is the clinical setting deserving further investigation on the value of the cholecystokinin provocative test, but this test needs to be standardized.

Acalculous biliary pain: new concepts for an old entity

Biliary pain is commonly reported in household surveys with the presumed cause being gallstones. When gallstones are absent or other abnormalities as a potential cause of similar pain do not exist, a different approach is necessary. Although trans-abdominal ultrasound can detect stones down to 3-5 mm, the advent of endoscopic ultrasound provides an even better definition for microlithiasis of < 3 mm. Duodenal aspiration of bile can further detect cholesterol microlithiasis or bilirubin granules, another potential source of biliary-type pain and perhaps even pancreatitis. Only in this way can acalculous gallbladder disease be clearly defined. The percentage of cholecystokinin-stimulated gallbladder emptying has been reputed to be the most sensitive diagnostic test for 'biliary dyskinesia', but abnormality of gallbladder emptying can be due to a smooth muscle defect of the gallbladder itself or heightened tone in the sphincter of Oddi. The value of surgical intervention has not been clearly established. The advent of laparoscopic cholecystectomy, however, has increased the number of patients with acalculous biliary disease who undergo surgery. Surgery is best done using impaired gallbladder emptying as the criterion for operation with improved outcome. Often, following cholecystectomy, biliary pain does not resolve the so-called 'post cholecystectomy syndrome'. Absence of the gallbladder as a pressure reservoir leaves the sphincter of Oddi as the prime determinant of bile duct pressure. Sphincter of Oddi dysfunction also exists in patients with an intact biliary tract and may become evident following cholecystectomy. Biliary manometry has clarified who might benefit from sphincterotomy. Choledochoscintigraphy is a non-invasive preliminary test. Advent of visceral hypersensitivity and better definition of this entity has shown, that in some of these patients with type III sphincter of Oddi, dysfunction appears to reside in duodenal hyperalgesia. It is clear that improved criteria are required to perform gallbladder emptying and better techniques to detect visceral hypersensitivity. Nonetheless, functional biliary pain in the absence of gallstone disease is a definite entity and a challenge for clinicians.

Involvement of cholecystokinin/gastrin-related peptides and their receptors in clinical gastrointestinal disorders

In this paper the possible roles of cholecystokinin (CCK), gastrin, or gastrin-related peptides and their receptors in human gastrointestinal diseases are reviewed. For CCK/CCK(A) receptors (CCK(A)-R), the evidence for their proposed involvement in diseases caused by impaired CCK release or CCK(A)-R mutations, pancreatic disorders (acute/chronic pancreatitis), gastrointestinal motility disorders (gallbladder disease, irritable bowel syndrome), pancreatic tumor growth and satiety disorders, is briefly reviewed. The evidence that has established the involvement of gastrin/CCK(B)-R in mediating the action of hypergastrinaemic disorders, mediating hypergastrinaemic effects on the gastric mucosa (ECL hyperplasia, carcinoids, parietal cell mass), and acid-peptic diseases, is reviewed. The evidence for their possible involvement in mediating growth of gastric and pancreatic tumours and possible involvement of gastrin-related peptides in colon cancers, is reviewed briefly.

Imaging benign and malignant disease of the gallbladder

This article reviews the imaging of various benign and malignant diseases of the gallbladder. Clinical findings and imaging features using ultrasound, CT, and MR for the detection and evaluation of gallstones, acute cholecystitis, xanthogranulomatous cholecystitis, adenomyomatosis, and carcinoma of the gallbladder among other disorders are discussed.