Acalculous gallbladder disease: a controversial entity and imaging dilemma revisited

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.

Gastrobiliary motility is not coordinated in patients with non-ulcer dyspepsia of normal gastric emptying time: simultaneous sonographic study

BACKGROUND

Disorders of the motor function of the upper gastrointestinal tract have been implicated in the pathogenesis of non-ulcer dyspepsia. Approximately 50% of patients with abdominal symptoms (without ulcer) have normal gastric emptying. Apart from gastric emptying, other mechanisms are very important in the etiology of non-ulcer dyspepsia.

METHODS

Gastric emptying and gallbladder motility were simultaneously investigated in 16 patients with non-ulcer dyspepsia and in 15 healthy controls. Fasting blood samples were taken, and pepsinogen levels were assayed.

RESULTS

Gastric emptying time, fasting antral diameter, and post-prandial antral diameter were not significantly different between the patients with non-ulcer dyspepsia and the controls. Fasting gallbladder volume, the time required to reach minimal gallbladder residual volume, minimal gallbladder residual volume, and the serum levels of pepsinogen were not significantly different. Simple linear regression was used to summarize the relationship between gastric emptying time and time required to reach minimal gallbladder residual volume. In the controls, the gastric emptying time and time required to reach minimal gallbladder residual volume were linearly related. However, in the patients with non-ulcer dyspepsia, they were not related.

CONCLUSIONS

These observations suggest that disturbance of coordination between gastric emptying and gallbladder emptying is a cause of the symptoms of non-ulcer dyspepsia.

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.

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.

Leptospirosis mimicking acute cholecystitis among athletes participating in a triathlon

Leptospirosis, a disease acquired by exposure to contaminated water, is characterized by fever accompanied by various symptoms, including abdominal pain. An acute febrile illness occurred in athletes who participated in an Illinois triathlon in which the swimming event took place in a freshwater lake. Of 876 athletes, 120 sought medical care and 22 were hospitalized. Two of the athletes had their gallbladders removed because of abdominal pain and clinical suspicion of acute cholecystitis. We applied an immunohistochemical test for leptospirosis to these gallbladders and demonstrated bacterial antigens staining (granular and filamentous patterns) around blood vessels of the serosa and muscle layer. Rare intact bacteria were seen in 1 case. These results show that leptospirosis can mimic the clinical symptoms of acute cholecystitis. If a cholecystectomy is performed in febrile patients with suspicious environmental or animal exposure, pathologic studies for leptospirosis on formalin-fixed, paraffin-embedded tissues may be of great value.

Gallbladder muscle dysfunction in patients with chronic acalculous disease

BACKGROUND & AIMS

The mechanisms responsible for the abnormalities of gallbladder emptying in patients with chronic acalculous gallbladder disease (AGD) have not been elucidated. This study was designed to determine whether a muscle defect could explain this gallbladder dysfunction.

METHODS

Gallbladder contraction induced by a continuous intravenous cholecystokinin octapeptide (CCK-8) infusion was determined by ultrasonography in control subjects, patients with AGD, pigment stones, and cholesterol stones. Muscle cells were obtained by enzymatic digestion. (125)I-CCK-8 binding and [(35)S]guanosine triphosphate gamma S (GTP gamma S) binding studies were performed.

RESULTS

In vivo gallbladder contraction induced by CCK-8 was significantly lower in AGD (29.4%) and cholesterol stones (28.8%) than in pigment stones (59.8%) and normal controls (57.8%; P < 0.01). In vitro muscle cell contraction induced by CCK-8 was also lower in AGD than in pigment stones. It remained impaired in AGD after stimulation with the G-protein activators GTP gamma S and AlF(4) and with the second messenger 1,2-dioctanoyl-sn-glycerol. However, GTP gamma S binding induced by CCK-8 and vasoactive intestinal polypeptide and the binding capacity of CCK receptors were not different between AGD and pigment stones.

CONCLUSIONS

These findings suggest that there is a good correlation between in vivo and in vitro gallbladder response to CCK-8 in patients with AGD. Unlike those found in cholesterol stones, the muscle defects in AGD appear to reside in the contractile apparatus.