Why does somatostatin cause gallstones?

Gastrointestinal side effects of somatostatin analogs in neuroendocrine tumors: a focused review

Neuroendocrine tumors (NETs) are a group of well-differentiated heterogeneous neoplasms characterized by slow progression and distinct clinical and biological behavior. In the majority of patients with NET, first-line treatment is represented by somatostatin analogs (SSAs) that, despite being drugs with high tolerability (even at high doses) and providing to carcinoid symptoms control and anti-proliferative effects, may present some side effects, with potential impact on quality of life and nutritional status. The most frequent side effects are represented by gastrointestinal events in particular alterations in bowel habits (diarrhea and constipation), abdominal pain, exocrine pancreatic insufficiency, and cholelithiasis. Considering the relative rarity of NETs, literature about frequency and standard clinical management of adverse events SSA-related is still lacking and heterogeneous. The aim of this review is to arm gastroenterologists and other physicians treating NET patients with essential knowledge on the side effects of SSAs. By identifying and managing these adverse events early, healthcare professionals can offer optimal care, avert foreseeable complications, and ensure the best outcomes for patients. Without such early recognition, there is a risk of diminishing the patient's quality of life and their ability to sustain treatment over time.

EUS-Guided Cholecystoduodenostomy for a Poor Surgical Candidate With Chronic Octreotide-Associated Gallstones From Metastatic Neuroendocrine Tumor

Chronic octreotide use has been associated with gallstone formation. Historically, cholecystectomy has been the defining treatment for those who have gallstone-related disease. For those who are poor surgical candidates, percutaneous and endoscopic approaches have been used. We describe the endoscopic management of a 74-year-old man with significant gallstone burden and associated sequelae because of chronic octreotide for metastatic neuroendocrine tumor through endoscopic ultrasound-guided cholecystoduodenostomy with gallstone extraction using lumen-apposing metal stents.

Small bowel neuroendocrine tumours - casting the net wide

PURPOSE OF REVIEW

Our aim is to provide an overview of small bowel neuroendocrine tumours (NETs), clinical presentation, diagnosis algorithm and management options. We also highlight the latest evidence on management and suggest areas for future research.

RECENT FINDINGS

Dodecanetetraacetic acid (DOTATATE) scan can detect NETs with an improved sensitivity than when compared with an Octreotide scan. It is complimentary to small bowel endoscopy that provides mucosal views and allows the delineation of small lesions undetectable on imaging. Surgical resection is the best management modality even in metastatic disease. Prognosis can be improved with the administration of somatostatin analogues and Evarolimus as second-line therapies.

SUMMARY

NETs are heterogenous tumours affecting most commonly the distal small bowel as single or multiple lesions. Their secretary behaviour can lead to symptoms, most commonly diarrhoea and weight loss. Metastases to the liver are associated with carcinoid syndrome.

Gallbladder Disorders: A Comprehensive Review

Gallbladder disorders encompass a wide breadth of diseases that vary in severity. We present a comprehensive review of literature for the clinical presentation, pathophysiology, diagnostic evaluation, and management of cholelithiasis-related disease, acute acalculous cholecystitis, functional gallbladder disorder, gallbladder polyps, gallbladder hydrops, porcelain gallbladder, and gallbladder cancer.

Management of Ileal Neuroendocrine Tumors with Liver Metastases

PURPOSE

Assessment of treating metastatic ileal neuroendocrine tumors (NETs) with complete resection of primary tumor, nodal and liver metastases, plus administration of long-acting somatostatin analogues (SSAs).

METHODS

A prospective database was queried for patients with ileal or pancreatic NETs with pathology-confirmed liver metastases and tumor somatostatin receptors. Patients did not have MEN-1 and had no previous treatment. The impacts of SSA treatment on the primary outcome of survival and secondary outcome of progression-free survival were assessed with Kaplan-Meier analysis. Log rank test was used to compare overall and progression-free survival among groups.

RESULTS

Seventeen ileal NET patients and 36 pancreatic NET patients who underwent surgical resection between 2001 and 2018, who had pathology-confirmed liver metastases and confirmed tumor somatostatin receptors, did not have MEN-1, and had no previous treatment were identified. Median follow-up for patients with ileal NETs was 80 months (range 0-197 months) and 32 months (range 1-182 months) for pancreatic NETs. Five-year survival was 93% and 72% for ileal and pancreatic NET, respectively. Progression-free 5-year survival was 70% and 36% for ileal and pancreatic NET, respectively. Overall 5-year survival for pNETs was greater in those patients treated with SSA (79%) compared to those who underwent surgery alone (34%, p < 0.01). The average ECOG score was low for surviving patients with ileal (0.15) and pancreatic NET (0.73) indicating a good quality of life.

CONCLUSIONS

Resection of primary lymph node and liver metastatic ileal or pancreatic NETs followed with continued SSAs is associated with an excellent progression-free and overall survival and minimal side effects.

The Role of the Small Bowel in Unintentional Weight Loss after Treatment of Upper Gastrointestinal Cancers

Upper gastrointestinal (GI) cancers are responsible for significant mortality and morbidity worldwide. To date, most of the studies focused on the treatments’ efficacy and post-treatment survival rate. As treatments improve, more patients survive long term, and thus the accompanying complications including unintentional weight loss are becoming more important. Unintentional weight loss is defined as >5% of body weight loss within 6–12 months. Malignancies, particularly GI cancers, are diagnosed in approximately 25% of patients who present with unintentional weight loss. Whereas some recent studies discuss pathophysiological mechanisms and new promising therapies of cancer cachexia, there is a lack of studies regarding the underlying mechanism of unintentional weight loss in patients who are tumor free and where cancer cachexia has been excluded. The small bowel is a central hub in metabolic regulation, energy homeostasis, and body weight control throughout the microbiota-gut-brain axis. In this narrative review article, the authors discussed the impacts of upper GI cancers’ treatment modalities on the small bowel which may lead to unintentional weight loss and some new promising therapeutic agents to treat unintentional weight loss in long term survivors after upper GI operations with curative intent.

Complication Follow-up With Ultrasonographic Analyses of 91 Cases With Donor Gallbladder Preservation in Living Donor Liver Transplantation of Left Lateral Sectionectomies

BACKGROUND

Preserving the donor's gallbladder during living donor liver transplantation (LDLT) is a better method for liver transplantation surgery, but not enough is known about gallbladder complications after the operation.

METHODS

We retrospectively investigated postsurgical donor gallbladder complications in clinical LDLT with gallbladder preservation. The feasibility of retaining the gallbladder during liver graft procurement is discussed. Ninety-one donors with retained gallbladder after LDLT with the hepatic left lateral sectionectomy (from June 2013 to October 2015) were retrospectively analyzed. Donors were followed for 12.6 to 40.7 months after surgery (median 26.1 months). Sonography was used to evaluate gallbladder characteristics before and after surgery.

RESULTS

Gallbladder function had recovered to almost normal 1 month after transplantation. Four donors (4.40%) experienced gallbladder enlargement that resolved after 3 days. Thickening of the gallbladder wall in 31 donors (34.07%) was restored within 2 to 75 days. Biliary sludge appeared in 9 donors (9.89%); 6 of them recovered within 3 to 34 days. Three (3.30%) and 1 donor (1.10%) suffered gallstone and gallbladder polyps, respectively, which persisted until the last follow-up.

CONCLUSION

The rate of postoperative complications of the gallbladder in donors was relative low. Preserving the gallbladder in liver transplantation donors during liver graft procurement is feasible and safe.

The Surgical Management of Small Bowel Neuroendocrine Tumors: Consensus Guidelines of the North American Neuroendocrine Tumor Society

Small bowel neuroendocrine tumors (SBNETs) have been increasing in frequency over the past decades, and are now the most common type of small bowel tumor. Consequently, general surgeons and surgical oncologists are seeing more patients with SBNETs in their practices than ever before. The management of these patients is often complex, owing to their secretion of hormones, frequent presentation with advanced disease, and difficulties with making the diagnosis of SBNETs. Despite these issues, even patients with advanced disease can have long-term survival. There are a number of scenarios which commonly arise in SBNET patients where it is difficult to determine the optimal management from the published data. To address these challenges for clinicians, a consensus conference was held assembling experts in the field to review and discuss the available literature and patterns of practice pertaining to specific management issues. This paper summarizes the important elements from these studies and the recommendations of the group for these questions regarding the management of SBNET patients.

Safety of octreotide in hospitalized infants

BACKGROUND

Octreotide is used off-label in infants for treatment of chylothorax, congenital hyperinsulinism, and gastrointestinal bleeding. The safety profile of octreotide in hospitalized infants has not been described; we sought to fill this information gap.

METHODS

We identified all infants exposed to at least 1 dose of octreotide from a cohort of 887,855 infants discharged from 333 neonatal intensive care units managed by the Pediatrix Medical Group between 1997 and 2012. We collected laboratory and clinical information while infants were exposed to octreotide and described the frequency of baseline diagnoses, laboratory abnormalities, and clinical adverse events (AEs).

RESULTS

A total of 428 infants received 490 courses of octreotide. The diagnoses most commonly associated with octreotide use were chylothorax (50%), pleural effusion (32%), and hypoglycemia (22%). The most common laboratory AEs that occurred during exposure to octreotide were thrombocytopenia (47/1000 infant-days), hyperkalemia (21/1000 infant-days), and leukocytosis (20/1000 infant-days). Hyperglycemia occurred in 1/1000 infant-days and hypoglycemia in 3/1000 infant-days. Hypotension requiring pressors (12%) was the most common clinical AE that occurred during exposure to octreotide. Necrotizing enterocolitis was observed in 9/490 (2%) courses, and death occurred in 11 (3%) infants during octreotide administration.

CONCLUSION

Relatively few AEs occurred during off-label use of octreotide in this cohort of infants. Additional studies are needed to further evaluate the safety, dosing, and efficacy of this medication in infants.

Variants in motilin, somatostatin and their receptor genes and risk of biliary tract cancers and stones in Shanghai, China

Altered motility of the gallbladder can result in gallstone and cholecystitis, which are important risk factors for biliary tract cancer. Motilin (MLN) and somatostatin (SST) are known important modulators of gallbladder motility. To determine whether genetic variants in motilin, somatostatin, and their receptor genes are associated with the risk of biliary tract cancers and stones, nine tag-SNPs were determined in 439 biliary tract cancer cases (253 gallbladder, 133 extrahepatic bile duct and 53 ampulla of Vater cancer cases), 429 biliary stone cases, and 447 population controls in a population-based case–control study in Shanghai, China. We found that subjects with the MLNR rs9568169 AA genotype and SSTR5 rs169068 CC genotype were significantly associated with risk of extrahepatic bile duct cancer (OR = 0.49, 95% CI: 0.27–0.89; OR = 2.40, 95% CI: 1.13–5.13) compared to the major genotypes. MLN rs2281820 CT and rs3793079 AT genotypes had significantly increased risks of gallstones (OR = 1.52, 95% CI: 1.06–2.18; OR = 1.64, 95% CI: 1.20–2.25) compared to TT genotypes. Besides, haplotype analysis showed that MLN T-T-T haplotype (rs2281820–rs3793079–rs2281819) had a non-significantly elevated risk of gallstone (OR = 1.30, 95% CI: 0.91–1.86) compared with C-A-A haplotype. To the best of our knowledge, this is the first study to report an association between genetic polymorphisms in MLN, MLNR and their receptor genes and risk of biliary tract cancers and stones.

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We conduct a population-based case–control study of biliary tract diseases in China.

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We examine nine TagSNPs in gallbladder motility genes in this study.

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MLNR rs9568169 and SSTR5 rs169068 are related to extrahepatic bile duct cancer risk.

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MLN rs2281820 and rs3793079 are associated with gallstone risk.

Pharmacokinetics and safety of subcutaneous pasireotide and intramuscular pasireotide long-acting release in Chinese male healthy volunteers: a phase I, single-center, open-label, randomized study

PURPOSE

The purpose of this study was to assess the pharmacokinetic (PK) properties and safety of single and multiple doses of subcutaneous (SC) pasireotide and a single-dose intramuscular (IM) long-acting release (LAR) formulation of pasireotide in Chinese healthy volunteers (HVs) versus the PK properties in Western HVs (pooled from previous PK studies).

METHODS

In this phase I, single-center, open-label study, 45 Chinese male HVs were evenly randomized to 1 to 9 treatment sequences: each volunteer received a single dose of 300, 600, or 900 μg of pasireotide SC on day 1, followed by administration of the same dose BID from day 15 to the morning of day 19, and then a single IM dose of 20, 40, or 60 mg of pasireotide LAR on day 33. The PK parameters were assessed with noncompartmental analysis. Statistical comparison of PK parameters, including AUC, Cmax, and CL/F from both formulations, was made for Chinese versus Western male HVs. The safety profile was also assessed. Metabolic parameters, including blood glucose, insulin, and glucagon, and measures that reflect the effects of pasireotide LAR on relatively long-term glucose control, lipid metabolism, and systemic concentrations of pancreatic enzymes and thyrotropin were evaluated.

FINDINGS

Of the 45 randomized HVs, 42 completed the study per protocol, 1 withdrew his informed consent for personal reasons, and 2 prematurely discontinued the study because of adverse events (AEs). Concentration-time and safety profiles of both formulations were similar to those reported in Western HVs. Mean geometric mean ratios (GMRs) of Chinese versus Western HVs ranged from 0.79 to 1.42. For most primary PK parameters, 90% CIs for GMRs were within a predefined ethnic insensitivity interval (90% CI, 0.70-1.43). After considering age and weight as covariates in the statistical model, the GMRs and 90% CIs for other PK parameters were within the predefined interval (Cmax in single-dose SC administration) or significantly decreased (Cmin,ss in multiple BID SC doses and first peak Cmax in the single-dose LAR formulation). No serious AEs were reported. Both formulations were well tolerated; pasireotide SC caused transient changes in glucose metabolism. Owing to the differential binding affinity to the somatostatin receptor subtypes, pasireotide LAR elicited a concentration-dependent increase of fasting blood glucose, substantial reduction in triglyceride, and a mild decrease in cholesterol. The most frequently reported AEs after single-dose and multiple-dose pasireotide SC were injection site reaction, nausea, dizziness, and diarrhea; most HVs developed diarrhea with single-dose pasireotide LAR.

IMPLICATIONS

The pasireotide formulations had similar PK and safety profiles between Chinese and Western male HVs. Thus, no ethnic sensitivity was found for pasireotide SC or LAR.

Somatostatin receptors: from signaling to clinical practice

Somatostatin is a peptide with a potent and broad antisecretory action, which makes it an invaluable drug target for the pharmacological management of pituitary adenomas and neuroendocrine tumors. Somatostatin receptors (SSTR1, 2A and B, 3, 4 and 5) belong to the G protein coupled receptor family and have a wide expression pattern in both normal tissues and solid tumors. Investigating the function of each SSTR in several tumor types has provided a wealth of information about the common but also distinct signaling cascades that suppress tumor cell proliferation, survival and angiogenesis. This provided the rationale for developing multireceptor-targeted somatostatin analogs and combination therapies with signaling-targeted agents such as inhibitors of the mammalian (or mechanistic) target of rapamycin (mTOR). The ability of SSTR to internalize and the development of rabiolabeled somatostatin analogs have improved the diagnosis and treatment of neuroendocrine tumors.

Somatostatin receptor subtypes 2 and 5 mediate inhibition of egg yolk-induced gall bladder emptying in mice

BACKGROUND

Somatostatin inhibits gall bladder contraction. Impaired gall bladder emptying is associated with gall bladder stone formation. The incidence of cholecystolithiasis is high in patients treated with a somatostatin agonist octreotide, which predominantly interacts with somatostatin receptor subtype 2 (SSTR2). Therefore, it is believed that SSTR2 regulates gall bladder contraction; however, evidence has not been provided. Here, we evaluate the effects of SSTR1-SSTR5-selective agonists on egg yolk-induced gall bladder contraction in mice.

METHODS

Homozygous deletion of SSTR2 and SSTR5 was generated by cross-mating of SSTR2(-/-) with SSTR5(-/-) mice. Mice of different genotypes were injected with SSTR1-5-selective agonists or octreotide 15 min before induction of gall bladder emptying by egg yolk. One hour later, gall bladders were removed and weighed.

KEY RESULTS

Egg yolk-reduced gall bladder weights in all mice, irrespective of their genotype. Octreotide was the most potent inhibitor of gall bladder emptying in wild-type mice. In contrast, agonists with high selectivity for SSTR2 or SSTR5 inhibited gall bladder emptying by approximately 50-60%, whereas SSTR1-, SSTR3- and SSTR4-selective agonists failed to influence gall bladder contraction. In SSTR2(-/-) mice, octreotide and an SSTR5-selective agonist inhibited gall bladder emptying by approximately 50%, whereas SSTR2-selective agonists were inactive. Octreotide inhibited gall bladder emptying in SSTR5(-/-) mice by approximately 50%, without any effect in SSTR2(-/-)/SSTR5(-/-) mice.

CONCLUSIONS & INFERENCES

Our study provides evidence for the role of SSTR2 and SSTR5 in regulating gall bladder emptying in mice.

Biliary sludge: the sluggish gallbladder

Biliary sludge is a mixture of particulate matter which has precipitated from bile. It generally consists of cholesterol monohydrate crystals, calcium bilirubinate or other calcium salts. In a clinical setting, biliary sludge is almost always an ultrasonographic diagnosis. Although it is less clinically applicable, direct microscopic examination of gallbladder bile is far more sensitive than ultrasonography into sludge detection, and has to be regarded as the diagnostic gold standard. The overall prevalence of sludge in the general population is relatively low. However, several clinical conditions are associated with a particularly high prevalence of biliary sludge, including pregnancy, rapid weight loss, total parenteral nutrition, octreotide therapy, bone marrow or solid organ transplantation. The clinical course of biliary sludge varies, and complete resolution, a waxing and waning course, and progression to gallstones are all possible outcomes. It may cause complications usually associated with gallstones, such as biliary colic, acute cholecystitis, and acute pancreatitis. The main pathogenic mechanism involved in sludge formation is probably gallbladder dismotility, and in selected patients measures aimed to maintain adequate gallbladder contractions has been shown to effectively prevent sludge development.

[Increased bile lithogenicity after simultaneous total parenteral nutrition and octrotide. A model of calcium palmitate Gallstones]

Gallbladder stasis and gallstone formation are well-known complications of both fasting-associated total parenteral nutrition (TPN) and long-term treatment with octreotide. Additive noxious effects to hepatobiliary function may develop when both therapies are given together as treatment of enteric fistulae. The aim of this study was to assess the risk of gallstone formation during treatment with TPN and octreotide separately and in combination. We studied four groups of New Zealand rabbits (n = 32) during a 2-week intervention period: 14 chow-fed controls; 6 fasted and TPN-fed; 6 chow-fed and administered octreotide, and 6 fasted and treated with both TPN and octreotide. After treatment, the bile duct was cannulated and the gallbladder and liver tissue were obtained for histological analysis. Hepatic and gallbladder bile were retrieved for microscopic examination and measurement of biliary lipids, bilirubin, calcium, total protein, and cholesterol nucleation time. The chemical composition of gallstones was also analyzed. The results of the study suggest that simultaneous administration of these two therapies in rabbits has additive effects on gallbladder stasis and bile lithogenicity. The administration of both treatments can play an important role in the formation of calcium palmitate gallstones in these animals.

Hepatolithiasis (intrahepatic stone) during octreotide therapy for acromegaly: a case report

We report a case of hepatolithiasis (intrahepatic stone) complicated by gram-negative sepsis in a 37 year old male with acromegaly being treated with octreotide. As a child, he had suffered a traumatic injury to his liver requiring the surgical repair of a laceration. This is the first reported case of hepatolithiasis during octreotide therapy. Gallstones and bile sludge are common side effects of octreotide therapy but rarely become symptomatic or require treatment. Hepatolithiasis is uncommon in western countries but is quite prevalent in East Asia and is often associated with a predisposing condition that causes intrahepatic bile stasis (eg. bile duct stricture). In addition to its known effect on gallbladder stasis, octreotide alters bile acid composition and may thus hasten intrahepatic sludge and stone formation. Extra caution should be taken in using octreotide or its long-acting analog in patients otherwise predisposed to intrahepatic bile stasis.

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.

Establishment and characterization of primary gallbladder epithelial cell cultures in the prairie dog

BACKGROUND

The prairie dog has become the established animal gallstone model. This species has a unique propensity to form cholesterol gallstones in response to dietary manipulations. The development of a reliable gallbladder cell culture technique is critical for understanding pathogenic mechanisms of gallstone formation.

MATERIALS AND METHODS

Prairie dogs underwent laparotomy and cholecystectomy, followed by initiation of cell cultures. [3H]Thymidine incorporation was used to assess cell growth, and cell lines were assessed using routine histochemical and immunohistochemical staining.

RESULTS

Cell yields from prairie dog gallbladders were 4-8 x 10(6) viable cells per animal with viability ranging from 80 to 95%. When plated at 5 x 10(5) cells/cm2, cell clusters, visible within 24 h, coalesced into confluent monolayers within 3-5 days. Cultures remained viable for 6-8 weeks and could be passed for three to four subcultures. Immunohistochemical staining demonstrated a high degree of epithelial purity with immunopositivity for AE1/AE3, and cytokeratin, with no vimentin positivity (mesenchymal antigen). Intracytoplasmic vacuoles demonstrated positive staining for Alcian blue, periodic acid-Schiff, and mucicarmine and an anti-gallbladder mucin antibody confirmed the presence of the glycoprotein mucin.

CONCLUSIONS

This study demonstrates a reliable method for initiation and maintenance of prairie dog gallbladder epithelial cell cultures with a high degree of purity. This technique should allow further studies into the pathogenesis of cholesterol gallstones in this model.

Gallbladder motility, gallstones, and the surgeon

Cholecystectomy is one of the commonest surgical procedures in the Western world, with more than half a million procedures performed annually in the United States alone. In recent years, studies of gallstone pathogenesis and gallbladder disease have increasingly focused on abnormal gallbladder motility in the pathogenesis of some, if not all, gallbladder conditions. The control of gallbladder motility is complex and depends on an intricate interplay of neural and hormonal factors. An understanding of the control of gallbladder motility is crucial to the understanding of the mechanisms of gallstone formation and may help to explain the failure to cure symptoms after cholecystectomy in up to one third of patients. The purpose of this article is to outline mechanisms controlling gallbladder motility, examine recent developments in our understanding of this complex process, and relate changes in motility to common disease conditions of the gallbladder. The role of altered motility in the pathogenesis of gallstones is discussed and the effects of commonly performed surgical procedures such as truncal vagotomy and cholecystectomy on upper gut physiology are reviewed.

Octreotide promotes gallbladder absorption in prairie dogs: a potential cause of gallstones

BACKGROUND/AIMS

Gallstone formation during octreotide administration has been causally linked to increased biliary concentrations of calcium, protein, and total lipids, all purported prolithogenic factors. These changes may be caused by octreotide-induced gallbladder stasis or a direct effect of octreotide on gallbladder absorption. We tested the hypothesis that octreotide stimulates gallbladder ion and water transport.

METHODS

Prairie dog gallbladders were mounted in Ussing chambers and bathed in oxygenated Ringer's solution. Electrophysiological parameters were recorded, and unidirectional Na+, Cl-, and H2O fluxes were measured before and after serosal exposure to 50 nmol/L octreotide.

RESULTS

Octreotide exposure caused a significant decrease in transepithelial short-circuit current and potential difference and an increase in tissue resistance compared with baseline. These alterations in electrophysiological parameters coincided with changes in ion transport. Octreotide stimulated net Na+ and H2O absorption and converted the gallbladder from a state of Cl- secretion to one of Cl- absorption by increasing mucosal to serosal fluxes. Octreotide effects on ion transport were blocked by 4,4'-diisothiocynostilbene-2,2'-disulfonic acid and amiloride and reversed by theophylline.

CONCLUSIONS

Octreotide may promote gallstone formation by inducing gallbladder stasis and by directly increasing gallbladder absorption, which may act synergistically to increase the concentration of prolithogenic factors in bile and to facilitate nucleation and stone growth.

Acute cholecystitis after autologous bone marrow transplantation for acute myeloid leukemia

BACKGROUND

We investigated the incidence of acute cholecystitis in patients with acute myeloid leukemia (AML) undergoing autologous bone marrow transplantation in complete remission.

PATIENTS AND METHODS

Thirty-five consecutive acute myeloid leukemia patients were given oral busulfan 4 mg/kg/day for 4 days and IV cyclophosphamide 50 mg/kg/day for 4 days followed by reinfusion of autologous bone marrow purged with 4-hydroperoxycyclophosphamide.

RESULTS

Five of 35 patients developed clinical evidence of acute cholecystitis, manifested by fever, nausea, vomiting, right-upper-quadrant pain, and abdominal guarding, within 18 days after autologous bone marrow infusion. Ultrasonography and CT scans of the abdomen supported the diagnosis of cholecystitis. Three patients underwent cholecystectomy, while two patients were treated medically; all recovered uneventfully. A review of 338 consecutive bone marrow transplant patients who underwent marrow transplantation for a variety of diseases and were treated with other high-dose cytotoxic regimens during the same time period revealed significantly fewer cases of cholecystitis, i.e. two, (p < 0.0001).

CONCLUSIONS

Five of 35 AML patients undergoing autologous bone marrow transplant using busulfan, cyclophosphamide, and purged bone marrow developed evidence of acute cholecystitis. These findings suggest that the busulfan/cyclophosphamide preparative regimen may be associated with acute cholecystitis. The true incidence of this injury and its pathogenesis remain to be elucidated.

Amelioration of intestinal dysmotility and stasis by octreotide early after small-bowel autotransplantation in dogs

BACKGROUND

Intestinal dysmotility and stasis after intestinal transplantation are considered to promote bacterial overgrowth and translocation. Two prokinetic agents, KW5139 (13-leu-motilin) and the somatostatin analogue octreotide acetate, were studied to determine whether they can ameliorate intestinal dysmotility during the early postoperative period.

MATERIALS AND METHODS

Motility was recorded by multiple extraluminal strain-gauge transducers in 6 dogs on postoperative days 1, 3, 7, and 14. A barium meal study was performed with a separate group of 8 dogs on postoperative days 3 and 7.

RESULTS

The agent KW5139 induced brief, weak contractions in the graft and had little effect on the dilated bowel; however, octreotide induced motor activity that propelled accumulated intestinal contents into the colon and reduced dilation of the transplanted bowel.

CONCLUSION

Octreotide, but not KW5139, ameliorates intestinal dysmotility associated with bowel autotransplantation during the early postoperative period. Short-term administration of octreotide may be useful for the treatment of dysmotility following intestinal transplantation.

The role of bile composition and physical chemistry in the pathogenesis of octreotide-associated gallbladder stones

BACKGROUND/AIMS

Treatment of acromegaly with octreotide inhibits cholecystokinin release and gallbladder contraction and induces gallbladder stones. However, little is known about the effects of octreotide on bile composition.

METHODS

Fresh gallbladder bile was obtained from three groups: (1) 11 nonacromegalic patients with cholesterol gallstones, (2) 6 acromegalic patients with octreotide-associated stones (treatment, 300-600 micrograms/day for 3-66 months), and (3) 8 acromogalic patients with no stones before octreotide treatment, 5 of whom were reexamined after 3-24 months of therapy.

RESULTS

Compared with stone-free acromegalic patients untreated with octreotide, bile from patients with cholesterol stones and from acromegalic patients with octreotide-associated stones had greater saturation indices (mean +/- SEM) (1.52 +/- 0.17 and 1.32 +/- 0.14 vs. 0.90 +/- 0.05, respectively; P < 0.01); more cholesterol in vesicles (61.2% +/- 4.5% and 67.7% +/- 7.2% vs. 37.7% +/- 3.5%; P < 0.009); more unstable vesicles (cholesterol/phospholipid ratios, 0.97 +/- 0.12 and 0.81 +/- 0.16 vs. 0.52 +/- 0.05; P < 0.02); more rapid nucleation (< 5 and < 5 days vs. > 18 days; P < 0.003); and more deoxycholic acid (22.8% +/- 2.4% and 23.6% +/- 4.8% vs. 13.9% +/- 1.4%; P < 0.05). In the paired studies, the saturation indices increased from 0.89 +/- 0.07 before octreotide treatment to 1.12 +/- 0.03 during octreotide treatment (P < 0.02), as did the percentage of deoxycholic acid from 13.3% +/- 2.1% to 24.9% +/- 2.7% (P < 0.03).

CONCLUSIONS

Acromegalic patients with octreotide-associated gallstones and stone-free acromegalic patients treated with octreotide have similar changes in bile composition to those in patients with "conventional" cholesterol gallstone disease.

Effects of octreotide on biliary lipid composition and occurrence of cholesterol crystals in patients with acromegaly. A prospective study

Treatment with the somatostatin analog octreotide is associated with increased gallstone formation. The mechanism of formation of these stones is unclear. The purpose of this study was to examine the effect of a three-month treatment with octreotide on biliary lipid composition and the occurrence of cholesterol crystals in patients with acromegaly. Thirteen patients with active acromegaly, aged 24-76 years, received octreotide (100 micrograms three times daily) for three months. Fasting gallbladder bile was obtained during upper gastrointestinal endoscopy after ceruletide stimulation. Bile was studied before and at the end of the treatment period (N = 7), only before (N = 4), or only at the end of treatment (N = 2). Before treatment, all bile samples but one were supersaturated with cholesterol. However, none contained cholesterol crystals on microscopic examination. At the end of the treatment period, all but two samples were supersaturated with cholesterol. Three of nine samples contained cholesterol crystals, a proportion significantly higher than before treatment. The relative proportions of bile acids, cholesterol, and phospholipids, and the mean cholesterol saturation index were not different before and during treatment. Follow-up ultrasonography showed the occurrence of gallstones in four patients, including the three patients who had cholesterol crystals. We conclude that: (1) fasting gallbladder bile of patients with acromegaly is frequently supersaturated with cholesterol; (2) treatment with octreotide does not increase cholesterol saturation index, but may induce the occurrence of cholesterol crystals. The data are consistent with the view that gallstones induced by octreotide are cholesterol stones and suggest that the drug may impair gallbladder motility and/or decrease cholesterol nucleation time.

Physiology and pathophysiology of gallbladder motility

Most significant gallbladder disease is associated with gallbladder stasis. Gallbladder motility is controlled by a complex interplay of hormonal and neural factors. Experimental and clinical studies have demonstrated impaired motility in gallstone disease, and experimental evidence indicates that motility disturbances precede gallstone formation. The ability to measure gallbladder motility clinically has also resulted in better diagnosis and treatment for patients with chronic acalculous cholecystitis.

Postprandial gall bladder motility and hormone release during intermittent and continuous subcutaneous octreotide treatment in acromegaly

Repeated daily injections of the somatostatin analogue, octreotide (SMS201-995, Sandostatin) are an effective treatment for acromegaly, but lead to gall stone formation in about 50% of cases during longterm treatment. This is probably because of impaired gall bladder contraction. This study examined whether the timing of intermittent injections in relation to meals, or alternatively, continuous 24 hour subcutaneous octreotide infusion (CSOI) might avert adverse effects on gall bladder contraction. In six patients with active acromegaly, gall bladder volume, plasma cholecystokinin (CCK), and pancreatic polypeptide (PP) were measured in the fasting state and after consumption of a fatty meal. Measurements were made on five separate days: (a) without treatment, (b) 45 minutes after 100 micrograms octreotide given subcutaneously, (c) four hours after 100 micrograms octreotide given subcutaneously, (d) eight hours after 100 micrograms octreotide given subcutaneously, and (e) during CSOI of 300 micrograms/24 h for two weeks. Without treatment, postprandial gall bladder contraction was 86.2 (2.1%). Fasting gall bladder volume increased after octreotide injection and was almost doubled during CSOI. Octreotide injections impaired postprandial gall bladder contraction as well as CCK and PP release for at least four hours. Eight hours after injection and during CSOI, postprandial gall bladder contraction was partly restored (43.4% and 50.8% respectively). Postprandial CCK release was normal at eight hours after injection but very low during CSOI. PP release was suppressed by each mode of octreotide treatment. This study indicates that octreotide injections impair postprandial gall bladder contraction for at least four hours. Eight hours after injection and during CSOI, gall bladder contraction is partly restored.

Effect of somatostatin analog octreotide on human sphincter of Oddi

The effect of the long-acting somatostatin analog octreotide on the sphincter of Oddi was investigated in seven subjects referred for endoscopic sphincter of Oddi manometry. Six patients had unexplained right upper quadrant pain and one had bile duct dilatation without evidence of fixed obstruction on endoscopic retrograde cholangiopancreatography. A triple-lumen low-compliance system was used to record the sphincter of Oddi basal pressure, phasic contraction frequency, amplitude, duration, and direction of wave propagation before and after intravenous administration of octreotide in a dose of 50 micrograms. After a mean latency period of 1 min, significant changes included increased basal pressure in all seven patients, increased frequency of wave contractions in six patients, and decreased wave amplitude in six patients. The median duration of wave contraction and wave propagation sequence were not significantly influenced. Thus, octreotide has a significant stimulatory affect on the sphincter of Oddi activity, which may impair biliary and pancreatic flow.

Drug-induced gallbladder disease. Incidence, aetiology and management

A great variety of drugs is reported to induce gallbladder disease by various pathogenetic mechanisms. Early epidemiological studies indicated a doubled risk of gallbladder disease in women taking oral contraceptives. More recent studies, however, have failed to confirm those findings; these conflicting results might be explained by the different methods used to define gallbladder disease. It was shown that the lithogenic index of the bile is increased during intake of oral contraceptives. Estrogens cause hypersecretion of cholesterol in bile, due to increase in lipoprotein uptake by the hepatocyte. Progesterone inhibits acyl coenzyme A-cholesterol acyl transferase (ACAT) activity, causing delayed conversion of cholesterol to cholesterol esters. Of the lipid lowering drugs, only clofibrate has been shown to increase the risk for gallstone formation. The other fibric acid derivatives have similar properties, but clinical experience is not as extensive. They seem to be inhibitors of the ACAT enzyme system, thereby rendering bile more lithogenic. Conflicting epidemiological data exist regarding the induction of acute cholecystitis by thiazide diuretics. Ceftriaxone, a third-generation cephalosporin, is reported to induce biliary sludge in 25 to 45% of patients, an effect which is reversible after discontinuing the drug. The sludge is occasionally a clinical problem. It was clearly demonstrated that this sludge is caused by precipitation of the calcium salt of ceftriaxone excreted in the bile. Long term use of octreotide is complicated by gallstone formation in approximately 50% of patients after 1 year of therapy, due to gallbladder stasis. Hepatic artery infusion chemotherapy by implanted pump is shown to be associated with a very high risk of chemically induced cholecystitis. Prophylactic cholecystectomy at the time of pump implantation is therefore advocated. Some drugs, such as erythromcyin or ampicillin, are reported to cause hypersensitivity-induced cholecystitis. Furthermore, there are reports on the influence of cyclosporin, dapsone, anticoagulant treatment, and narcotic and anticholinergic medication in causing gallbladder disease.