Long-term outcome of endoscopic therapy in patients with bile duct injury after cholecystectomy

BACKGROUND AND AIM

Bile duct lesions, including leaks and strictures, are immanent complications of open or laparoscopic cholecystectomy. Endoscopic procedures have gained increasing potential as the treatment of choice in the management of postoperative bile duct injuries.

METHODS

Between January 1996 and December 2006, 44 patients with biliary leakages and 12 patients with biliary strictures after cholecystectomy were identified by analyzing the endoscopic retrograde cholangiopancreatography database, clinical records, and cholangiograms. The long-term follow up of endoscopic treatment in biliary lesions after cholecystectomy was evaluated by this retrospective study.

RESULTS

In 34 of 35 patients (97%) with peripheral bile duct leakages, endoscopic therapy was successful. Transpapillary endoprothesis and/or nasobiliary drainage were removed after 31 (5-399) days. After stent removal, the median follow-up period was 81 (11-137) months. In patients with central bile duct leakages, the success rate after median 90 (4-145) days of endoscopic therapy was 66.7% (6/9 patients). The median follow up after stent removal in six successfully treated patients was 70 (48-92) months. Eleven of 12 patients (91.6%) with bile duct strictures had successfully completed stent therapy. The follow-up period of this patient group was 99 (53-140) months.

CONCLUSIONS

Endoscopic treatment of bile duct lesions after cholecystectomy is effective, particularly in patients with peripheral bile duct leakages and bile duct strictures. Therefore, it should be the first-line therapy used in these patients. Although endoscopic management is less successful in patients with central bile duct leakages, an attempt is warranted.

Infected necrosis in severe pancreatitis--combined nonsurgical multi-drainage with directed transabdominal high-volume lavage in critically ill patients

BACKGROUND

Infection of pancreatic necrosis is a life-threatening complication during the course of acute pancreatitis. In critically ill patients, surgical or extended endoscopic interventions are associated with high morbidity and mortality. Minimally invasive procedures on the other hand are often insufficient in patients suffering from large necrotic areas containing solid or purulent material. We present a strategy combining percutaneous and transgastric drainage with continuous high-volume lavage for treatment of extended necroses and liquid collections in a series of patients with severe acute pancreatitis.

PATIENTS AND METHODS

Seven consecutive patients with severe acute pancreatitis and large confluent infected pancreatic necrosis were enrolled. In all cases, the first therapeutic procedure was placement of a CT-guided drainage catheter into the fluid collection surrounding peripancreatic necrosis. Thereafter, a second endosonographically guided drainage was inserted via the gastric or the duodenal wall. After communication between the separate drains had been proven, an external to internal directed high-volume lavage with a daily volume of 500 ml up to 2,000 ml was started.

RESULTS

In all patients, pancreatic necrosis/liquid collections could be resolved completely by the presented regime. No patient died in the course of our study. After initiation of the directed high-volume lavage, there was a significant clinical improvement in all patients. Double drainage was performed for a median of 101 days, high-volume lavage for a median of 41 days. Several endoscopic interventions for stent replacement were required (median 8). Complications such as bleeding or perforation could be managed endoscopically, and no subsequent surgical therapy was necessary. All patients could be dismissed from the hospital after a median duration of 78 days.

CONCLUSION

This approach of combined percutaneous/endoscopic drainage with high-volume lavage shows promising results in critically ill patients with extended infected pancreatic necrosis and high risk of surgical intervention. Neither surgical nor endoscopic necrosectomy was necessary in any of our patients.

Long-term follow-up of percutaneous transhepatic biliary drainage (PTBD) in patients with benign bilioenterostomy stricture

BACKGROUND AND AIMS

Anastomotic strictures are well-known complications after bilioenterostomy. Endoscopic procedures are usually not possible in patients with a bilioenterostomy. Hence, percutaneous transhepatic biliary drainage (PTBD) has become the treatment of choice for the management of these patients. The main goal of the present study was to analyze the long-term follow-up of PTBD in such patients.

METHODS AND PATIENTS

Between January 1996 and December 2006, 44 patients with benign anastomotic stricture after bilioenterostomy were identified by an analysis of the PTBD database, hospital charts, and cholangiograms.

RESULTS

In 27/44 patients the percutaneous transhepatic biliary drain was successfully removed after 19.9 +/- 16.1 months (treatment success in 61.4 %). During a mean follow-up of 53.7 +/- 28.4 months after removal of the drain, no evidence was found of recurrent strictures in these patients. Ten out of 44 patients carry permanent drains (22.6 % of patients with ongoing treatment, mean follow-up 46.4 +/- 54.7 months) without the option for further surgery owing to concomitant disease (n = 2) or because they refused further surgery (n = 8). In 7 out of 44 patients (16 %) PTBD treatment was deemed to have failed and the patients underwent repeat operation.

CONCLUSIONS

PTBD should be considered the treatment of choice in patients with benign anastomotic stricture after bilioenterostomy, especially after stricturing of a hepatojejunostomy.

Validation of the X-Vision ERCP Training System and technical challenges during early training of sphincterotomy

BACKGROUND & AIMS

A new fluoroscopy-free training system for endoscopic retrograde cholangiopancreatography (ERCP) with different model subtypes recently was developed. This study aimed to establish construct validity by investigating whether the X-Vision ERCP Training System could distinguish experienced endoscopists from beginners and to reveal characteristic mistakes during sphincterotomy.

METHODS

Six staff gastroenterologists that practice ERCP, 10 trainees that perform esophagogastroduodenoscopy and colonoscopy, and 12 residents without endoscopic experience each sequentially attempted 4 different models, simulating selective cannulation of the pancreatic or bile duct, intubation of differently arranged rubber papillas, stent placement, and sphincterotomy of a biopapilla. Performance parameters were recorded and participants' expectations were compared before and after training to determine whether the simulator was a credible tool for ERCP training. Staff gastroenterologists graded the realism and utility of the simulation. The quality of sphincterotomy was assessed by an expert endoscopist.

RESULTS

Participants with ERCP experience had significantly shorter procedure times compared with those with intermediate (P < .001) or no endoscopic experience (P < .001). Total and single credibility scores significantly increased after simulator practice. The faculty found the X-Vision ERCP Training System to be realistic and useful for training. In the less-experienced groups, common mistakes made during sphincterotomy included inadequate positioning of the duodenoscope, traumatic intubation of the papilla, and continued cutting despite insufficient endoscopic view.

CONCLUSIONS

The X-Vision ERCP Training System distinguished subjects with different levels of experience and was regarded as realistic and useful for ERCP training. Common mistakes during sphincterotomy could be assessed objectively.

Auditory evoked potentials compared with bispectral index for monitoring of midazolam and propofol sedation during colonoscopy

OBJECTIVES

The purpose of this study was to evaluate and compare Bispectral index (BIS) and A-line auditory evoked potential index (AAI) for monitoring depth of low-dose midazolam and propofol sedation during colonoscopy.

METHODS

A total of 115 consecutive patients (ASA I-IV), receiving low-dose midazolam and propofol sedation for colonoscopy, were evaluated. BIS and AAI levels, Observer's Assessment of Alertness/Sedation (OAA/S) scores, blood pressure, heart rate, oxygen saturation, as well as the presence or absence of eyelash reflex, patient reaction to an external noxious stimulus and to procedure-related pain were recorded every 1-3 min by a single trained observer.

RESULTS

There was a positive correlation between BIS and OAA/S scores (correlation coefficient=0.77) and to a lesser extent AAI and OAA/S scores (correlation coefficient=0.47). BIS and AAI showed significant differences between subsequent levels of sedation (P<0.001). The clustered receiver operating characteristic curve estimate of BIS for the detection of deep sedation was significantly better than that of AAI (P<0.001). Regarding the presence or absence of eyelash reflex and patient reaction to an external noxious stimulus and to procedure-related pain, significant different levels were found for BIS as well as AAI, respectively. Only small changes were observed in hemodynamic variables and oxygen saturation. Overall, our data suggest target BIS levels of slightly above 73 for moderate sedation (defined as OAA/S scores 2 and 3).

CONCLUSIONS

BIS and AAI correlated with the level of sedation. Hemodynamic variables were poor indicators of the hypnotic-anesthetic status of the patient. BIS discriminated best between moderate and deep sedation and could complement clinical observation for guidance of moderate sedation.

[S3-guideline "Helicobacter pylori and gastroduodenal ulcer disease"]

This guideline updates a prior concensus recommendation of the German Society for Digestive and Metabolic Diseases (DGVS) from 1996. It was developed by an interdisciplinary cooperation with representatives of the German Society for Microbiology, the Society for Pediatric Gastroenterology and Nutrition (GPGE) and the German Society for Rheumatology. The guideline is methodologically based on recommendations of the Association of the Scientific Medical Societies in Germany (AWMF) for providing a systematic evidence-based consensus guideline of S 3 level and has also implemented grading criteria according to GRADE (Grading of Recommendations Assessment, Development and Evaluation). Clinical applicability of study results as well as specifics for Germany in terms of epidemiology, antibiotic resistance status, diagnostics and therapy were taken into account.

Correlation of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinase expression in ileal carcinoids, lymph nodes and liver metastasis with prognosis and survival

PURPOSE

Ileal carcinoids are gut epithelial tumors originating from serotonin-containing enterochromaffin (EC) cells. Therapeutic options for effectively inhibiting the growth and spread of metastatic carcinoids are still limited. We aimed to identify the role of matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors (TIMPs) during tumor development and metastasis.

PATIENTS AND METHODS

Tissue samples were obtained from surgically treated patients. Expression of the EC-cell marker, vesicular monoamine transporter-1 (VMAT-1), was used to verify ileal carcinoids. We investigated the differential expression of MMP-2, 7, 9, 11, and 13 and their endogenous inhibitors (TIMP-1, 2, and 3) by quantitative real-time RT-PCR in 25 primary tumors, their corresponding lymph node metastases and/or liver metastases and matched normal mucosa.

RESULTS

Significantly increased expression of VMAT-1, MMP-2, MMP-11, TIMP-1 and TIMP-3 was determined by quantitative RT-PCR in EC-cell carcinoids compared to normal intestinal mucosa (p < 0.05). In contrast, MMP-2 and MMP-9 as well as TIMP-1, TIMP-2, and TIMP-3 expression in primary tumors of patients with liver metastases (M1) was significantly lower than in patients lacking liver metastases (M0). EC-cell tumors were significantly larger in the M1 group of tumors, while VMAT-1 expression was significantly decreased. We found an inverse correlation between tumor size and prognosis. Univariate analysis further revealed that decreased expression of VMAT-1, MMP-2 and TIMP-3 in primary tumors was significantly associated with a reduced survival time of the patients.

CONCLUSION

Our data reveal that MMP-2 and TIMP-3 expression together with VMAT-1 expression are of potential prognostic and clinical value in ileal carcinoids.

Vascular endothelial growth factors, angiogenesis, and survival in human ileal enterochromaffin cell carcinoids

BACKGROUND AND AIMS

Well-differentiated neuro-endocrine ileal carcinoids are composed of serotonin-producing enterochromaffin (EC) cells. Life expectancy is determined by metastatic spread to the liver because medical treatment options are still very limited. Selective inhibition of angiogenesis or lymphangiogenesis might prevent tumour growth and metastatic spread. We examined the role of the vascular endothelial growth factors (VEGFs) A, B, C, D, and their receptors (VEGFRs) 1, 2, 3 in angiogenesis and lymphangiogenesis of ileal EC cell carcinoids with and without liver metastases.

METHODS

The expression of various VEGFs and VEGFRs was determined by quantitative real-time RT-PCR in healthy mucosa, primary tumour, lymph node metastases and liver metastases of 25 patients with ileal EC cell carcinoids. Microvessel density (MVD) was determined by CD-31 staining in primary tumours and lymphatic vessel density (LVD) by LYVE-1 staining. VEGF expression levels, MVD, LVD, and patients' survival time were correlated using logistic regression and Kaplan-Meier survival analysis.

RESULTS

VEGF-A was highly expressed with no difference between normal mucosa and tumours. VEGF-B and -D as well as VEGFR-1 and -2 expression levels were significantly increased in the tumours when compared to normal mucosa. Patients with liver metastasis, however, had a significantly lower expression of the factors A, B, and C and the receptors 2 and 3. MVD in primary tumours positively correlated with the expression of VEGF ligands and their receptors, except for VEGF-D. LVD did not correlate with any VEGF ligand or receptor. Interestingly, low expression levels of VEGF-B were associated with poor survival.

CONCLUSION

Patients with more aggressive metastatic spreading had relatively decreased expression levels of VEGF ligands and receptors. Thus, anti-angiogenic therapy may not be a suitable target in metastatic ileal EC cell carcinoids.

Do we need gastric acid?

Evidence from comparative anatomy and physiology studies indicates that gastric acid secretion developed during the evolution of vertebrates approximately 350 million years ago. The cellular mechanisms that produce gastric acid have been conserved over the millennia and therefore proton pump inhibitors have pharmacological effects in almost all relevant species. These observations suggest that gastric acid provides an important selective advantage; however, in modern-day humans the need for gastric acid can be questioned in light of the widespread use of safe and effective pharmacologic acid suppression. The Kandahar Working Group addressed questions concerning the need, production and effects of gastric acid, specifically: (1) motility in the upper gastrointestinal (GI) tract; (2) neuroendocrine factors; (3) digestive and mucosal processes; (4) microbiology, and (5) central processes and psychological involvement. We addressed each topic with the individual models available to answer our questions including animal versus human studies, pharmacologic, surgical as well as pathophysiologic states of acid suppression.

Complications of percutaneous transhepatic biliary drainage in patients with dilated and nondilated intrahepatic bile ducts

Percutaneous transhepatic biliary drainage (PTBD) have been described as an effective technique to obtain biliary access. Between January 1996 and December 2006, a total of 419 consecutive patients with endoscopically inaccessible bile ducts underwent PTBD. The current retrospective study evaluated success and complication rates of this invasive technique. PTBD was successful in 410/419 patients (97%). The success rate was equal in patients with dilated and nondilated bile ducts (p=0.820). In 39/419 patients (9%) procedure related complications could be observed. Major complications occurred in 17/419 patients (4%). Patients with nondilated intrahepatic bile ducts had significantly higher complication rates compared to patients with dilated intrahepatic bile ducts (14.5% vs. 6.9%, respectively [p=0.022]). Procedure related deaths were observed in 3 patients (0.7%). In conclusion, percutaneous transhepatic biliary drainage is an effective procedure in patients with dilated and nondilated intrahepatic bile ducts. However, patients with nondilated intrahepatic bile ducts showed a higher risk for procedure related complications.

Detection of cholangiocarcinoma in vivo using miniprobe-based confocal fluorescence microscopy

BACKGROUND & AIMS

The preoperative diagnosis of cholangiocarcinoma is associated with a low sensitivity. To overcome this limitation, a new imaging modality was evaluated to detect neoplasia in vivo in the biliary tract.

METHODS

Fourteen patients with biliary strictures were examined. Mucosal imaging was performed with a miniaturized confocal laser scanning miniprobe introduced via the accessory channel of a cholangioscope. Thereafter, targeted biopsy specimens were taken from the same regions.

RESULTS

All strictures could be reached. Presence of irregular vessels use confocal laser microscopy enabled prediction of neoplasia with an accuracy rate of 86%, sensitivity of 83%, and specificity of 88%. The respective numbers for standard histopathology were 79%, 50%, and 100%. The mean signal-to-noise-ratio of laser microscopic images acquired from malignant strictures differed significantly from those of benign origin (1.8 +/- 0.8 vs 2.6 +/- 1.0; P = .005).

CONCLUSIONS

Miniprobe-based confocal laser scanning microscopy considerably increases sensitivity for the detection of biliary neoplasia and therefore represents a promising diagnostic approach.

Diagnostic approaches for cholangiocarcinoma

Cholangiocarcinomas arise from the epithelial cells of the bile ducts and are associated with poor prognosis. Despite new diagnostic approaches, the definite diagnosis of this malignancy continues to be challenging. Cholangiocarcinomas often grow longitudinally along the bile duct rather than in a radial direction. Thus, large tumor masses are frequently absent and imaging techniques, including ultrasound, CT, and MRI have only limited sensitivity. Tissue collection during endoscopic (ERCP) and/or percutaneous transhepatic (PTC) procedures are usually used to confirm a definitive diagnosis of cholangiocarcinoma. However, forceps biopsy and brush cytology provide positive results for malignancy in about only 50% of patients. Percutaneous and peroral cholangioscopy using fiber-optic techniques were therefore developed for direct visualization of the biliary tree, yielding additional information about endoscopic appearance and tumor extension, as well as a guided biopsy acquistion. Finally, endoscopic ultrasonography (EUS) complements endoscopic and percutaneous approaches and may provide a tissue diagnosis of tumors in the biliary region through fine-needle aspiration. In the future, new techniques allowing for early detection, including molecular markers, should be developed to improve the diagnostic sensitivity in this increasing tumor entity.

A novel and practicable ERCP training system with simulated fluoroscopy

INTRODUCTION

Simulators facilitate the acquisition of technical skills for endoscopy. Here, we describe the development, introduction, and first evaluation of a novel generation of mechanical endoscopic retrograde cholangiopancreatography (ERCP) simulation models with simulated fluoroscopy, the X-Vision ERCP Training System.

METHODS

A custom-made modular ERCP simulation system was built with the use of universally obtainable materials and tools. The trainee controls ERCP activities on two screens: the aspect of the papilla and duodenum is shown on the conventional endoscopy monitor, and the trainee's actions in the equivalents of the pancreaticobiliary ducts are shown on the viewing screen of the model. Thereby, the latter screen serves as a substitute for fluoroscopy. Currently, four different models are available, allowing simulation of selective cannulation of the pancreatic or bile duct, intubation of differently arranged papillae, stent placement, and sphincterotomy of a biopapilla. The X-Vision ERCP Training System was first used during an ERCP course attended by 26 endoscopists. Trainees were supervised by an ERCP expert and an experienced ERCP nurse at each training model. The training system was evaluated by the participants and experts using a specific questionnaire.

RESULTS

During the course there were no technical problems related to the X-Vision ERCP Training System. After sphincterotomy the organic papillae could easily be exchanged within less than 15 seconds. Overall, the X-Vision ERCP Training System achieved favorable results in all categories assessed.

CONCLUSION

The new X-Vision ERCP Training System is simple and effective. A first evaluation in the context of an ERCP course showed impressive results.

In vitro activity of moxifloxacin and piperacillin/sulbactam against pathogens of acute cholangitis

AIM: To analyze the in vitro activity of moxifloxacin and piperacillin/sulbactam against pathogens isolated from patients with acute cholangitis.

METHODS: In this prospective study a total of 65 patients with acute cholangitis due to biliary stone obstruction (n = 7), benign biliary stricture (n = 16), and malignant biliary stricture (n = 42) were investigated with regard to spectrum of bacterial infection and antibiotic resistance. Pathogens were isolated from bile cultures in all study patients. In 22 febrile patients, blood cultures were also obtained. In vitro activity of moxifloxacin and piperacillin/sulbactam was determined by agar diffusion.

RESULTS: Thirty-one out of 65 patients had positive bile and/or blood cultures. In 31 patients, 63 isolates with 17 different species were identified. The predominant strains were Enterococcus species (26/63), E.coli (13/63) and Klebsiella species (8/63). A comparable in vitro activity of moxifloxacin and piperacillin/sulbactam was observed for E.coli and Klebsiella species. In contrast, Enterococcus species had higher resistances towards moxifloxacin. Overall bacteria showed antibiotic resistances in vitro of 34.9% for piperacillin/sulbactam and 36.5% for moxifloxacin.

CONCLUSION: Enterococcus species, E.coli and Klebsiella species were the most common bacteria isolated from bile and/or blood from patients with acute cholangitis. Overall, a mixed infection with several species was observed, and bacteria showed a comparable in vitro activity for piperacillin/sulbactam and moxifloxacin.

Endoscopic transpapillary brush cytology and forceps biopsy in patients with hilar cholangiocarcinoma

AIM: To evaluate the sensitivity of brush cytology and forceps biopsy in a homogeneous patient group with hilar cholangiocarcinoma.

METHODS: Brush cytology and forceps biopsy were routinely performed in patients with suspected malignant biliary strictures. Fifty-eight consecutive patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) including forceps biopsy and brush cytology in patients with hilar cholangiocarcinoma between 1995-2005.

RESULTS: Positive results for malignancy were obtained in 24/58 patients (41.4%) by brush cytology and in 31/58 patients (53.4%) by forceps biopsy. The combination of both techniques brush cytology and forceps biopsy resulted only in a minor increase in diagnostic sensitivity to 60.3% (35/58 patients). In 20/58 patients (34.5%), diagnosis were obtained by both positive cytology and positive histology, in 11/58 (19%) by positive histology (negative cytology) and only 4/58 patients (6.9%) were confirmed by positive cytology (negative histology).

CONCLUSION: Brush cytology and forceps biopsy have only limited sensitivity for the diagnosis of malignant hilar tumors. In our eyes, additional diagnostic techniques should be evaluated and should become routine in patients with negative cytological and histological findings.

In vivo histopathology for detection of gastrointestinal neoplasia with a portable, confocal miniprobe: an examiner blinded analysis

BACKGROUND & AIMS

Confocal fluorescence microscopy (CFM) has been mentioned to be a promising tool for in vivo histology. Recently, a portable confocal miniprobe has been developed. Our aim was to evaluate the potential benefit of CFM for detection of gastrointestinal neoplasia.

METHODS

A total of 47 patients with known or suspected neoplasia in the upper (n = 34) or lower gastrointestinal tract (n = 13) were examined with standard endoscopes. After mucolyis with 5-10 mL of acetic acid 1.5%, chromoendoscopy with 2-5 mL cresyl violet 0.25% was performed, with the substance also being used as a fluorophore for CFM. Real-time video sequences were recorded. Thereafter, biopsies were taken or mucosectomy/polypectomy was performed from the same examined area. All stored sequences were put into a random order and assessed by a pathologist and a gastroenterologist both blinded to any data.

RESULTS

A total of 119 CFM video sequences were recorded of 85 benign or 34 neoplastic areas. Quality of CFM images was regarded too low in 24 (pathologist) and 14 sequences (gastroenterologist). For the pathologist, accuracy of CFM detecting neoplasia was 92.6% (suitable images) and 73.9% (intention to diagnose). The respective accuracy values for the gastroenterologist were 92.4% (suitable images) and 81.5% (intention to diagnose). Agreement between CFM and histopathology was excellent (kappa values, 0.821 and 0.817).

CONCLUSIONS

We have demonstrated that CFM with a miniprobe has the potential to diagnose neoplasia during ongoing endoscopy. This system has the advantage that it can be used with standard endoscopes. Further studies are warranted for validation.

High-resolution miniprobe-based confocal microscopy in combination with video mosaicing (with video)

BACKGROUND

A new portable confocal laser microscopy system has recently been developed.

OBJECTIVE

Our purpose was to evaluate the feasibility of performing real-time microscopic imaging with a prototype of a new high-resolution miniprobe in conjunction with a video mosaicing algorithm.

DESIGN

Feasibility study.

SETTING

Tertiary referral center at a large university hospital.

PATIENTS

Seven patients referred for endoscopy for various indications.

MAIN OUTCOME MEASUREMENTS

High-resolution laser microscopy of the upper and lower GI tract was performed with standard endoscopes. Seven to 10 mL of 1% fluorescein was injected intravenously a few seconds before the procedure. No additional preparation was required. The prototype used has a lateral resolution of 1.2 microm and an axial resolution of 3 mum with a total field of 240 x 200 microm. From all stored video sequences a video mosaicing algorithm was used to combine the successive individual images, cancel motion artifacts, and reconstitute panoramas of the tissues.

RESULTS

Cell-to-cell borders, single cell structures, and mucosal inflammation was readily detectable. By the use of the mosaicing algorithm, the image area could be increased 2- to 4-fold, and image definition could be further enhanced to allow finer detail visualization.

LIMITATIONS

Low number of patients, early feasibility study.

CONCLUSIONS

Our preliminary data show that high-resolution miniprobe-based confocal fluorescence microscopy in conjunction with video mosaicing has the potential to provide images similar to standard histopathologic studies. Dynamic images with a smaller field of view can be combined to reconstruct still images of high resolution covering a fairly large area.

Submucosal endoscopy: a novel approach to en bloc endoscopic mucosal resection (with videos)

BACKGROUND

The submucosal layer is of eminent importance for endoscopic mucosal resection (EMR) in the GI tract.

OBJECTIVE

Development of submucosal endoscopy, which allows diagnostic and therapeutic endoscopy of the submucosal space (SS) in the esophagus.

DESIGN

Acute experiments in a live porcine model.

INTERVENTIONS

An area in the esophagus was marked with a diathermic probe to define a mucosal piece for resection. After local infiltration, a 1- to 2-cm transverse incision was performed 1 to 2 cm proximal and distal of these margins. We entered the SS with a flexible small-caliber videoendoscope through the proximal incision and dissected the fibrous submucosal connective tissue in a longitudinal direction with a blunt forceps. For EMR, the lifted mucosa was subsequently separated by use of an insulated-tip hook needle-knife.

MAIN OUTCOME MEASUREMENTS

En bloc resection of prespecified mucosal areas.

RESULTS

A total of 15 mucosal pieces were resected in 4 pigs. The size of the resected pieces varied from 1.6 cm x 0.9 cm to 7.4 cm x 1.7 cm ex vivo. In a fifth pig, 2 circular mucosectomies (lengths 3.0 cm and 1.6 cm) were done. All mucosal pieces could be completely resected en bloc. The endoscopic view in the SS was excellent. There were no procedure-related complications.

LIMITATIONS

The method has not yet been evaluated in humans.

CONCLUSIONS

Entering the SS for submucosal endoscopy is a novel, innovative, and practicable method for the dissection of mucosal neoplastic lesions. We demonstrated that mucosal areas of various sizes could be resected en bloc without complications.

Lack of RUNX3 regulation in human gastric cancer

It has been proposed that the transcription factor RUNX3 is the product of a gastric tumour suppressor gene. We examined RUNX3 expression in gastric biopsies from 105 patients with different histological presentations. Surprisingly, immunohistochemical staining detected RUNX3 protein expression only in infiltrating leukocytes but not in the gastric epithelium. Using laser capture microdissection and quantitative reverse transcription-polymerase chain reaction, we confirmed that the level of RUNX3 mRNA expression in the gastric epithelium was very low and was influenced neither by H. pylori infection nor by neoplastic transformation. Instead, RUNX3 was highly expressed in the gastric stroma and the level of expression correlated with the magnitude of H. pylori-induced gastric inflammation. The low level of RUNX3 expression in gastric epithelium and the absence of downregulation in gastric cancer do not support the hypothesis that RUNX3 functions as a gastric tumour suppressor gene.

Enterochromaffin cells of the human gut: sensors for spices and odorants

BACKGROUND & AIMS

Release of serotonin from mucosal enterochromaffin cells triggered by luminal substances is the key event in the regulation of gut motility and secretion. We were interested to know whether nasal olfactory receptors are also expressed in the human gut mucosa by enterochromaffin cells and whether their ligands and odorants present in spices, fragrances, detergents, and cosmetics cause serotonin release.

METHODS

Receptor expression was studied by the reverse-transcription polymerase chain reaction method in human mucosal enterochromaffin cells isolated by laser microdissection and in a cell line derived from human enterochromaffin cells. Activation of the cells by odorants was investigated by digital fluorescence imaging using the fluorescent Ca(2+) indicator Fluo-4. Serotonin release was measured in culture supernatants by a serotonin enzyme immunoassay and amperometry using carbon fiber microelectrodes placed on single cells.

RESULTS

We found expression of 4 olfactory receptors in microdissected human mucosal enterochromaffin cells and in a cell line derived from human enterochromaffin cells. Ca(2+) imaging studies revealed that odorant ligands of the identified olfactory receptors cause Ca(2+) influx, elevation of intracellular free Ca(2+) levels, and, consequently, serotonin release.

CONCLUSIONS

Our results show that odorants present in the luminal environment of the gut may stimulate serotonin release via olfactory receptors present in human enterochromaffin cells. Serotonin controls both gut motility and secretion and is implicated in pathologic conditions such as vomiting, diarrhea, and irritable bowel syndrome. Thus, olfactory receptors are potential novel targets for the treatment of gastrointestinal diseases and motility disorders.

Inhibition of T-cell proliferation by Helicobacter pylori gamma-glutamyl transpeptidase

BACKGROUND & AIMS

Helicobacter pylori colonizes the human gastric mucosa of >50% of the world's population. Most of the patients have no overt clinical symptoms. However, the infection is invariably associated with the development of active chronic gastritis, leading in some cases to the development of peptic ulcer disease, distal gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. In contrast to most other pathogens, infection with H pylori persists lifelong, but reasons for the persistence remain obscure. CD4-positive T cells are crucial for bacterial elimination but are inhibited by H pylori. We aimed to identify the factor responsible for suppression of T-cell response and characterize this inhibitory effect on a cellular and molecular level.

METHODS

Using size-exclusion chromatography, sodium dodecyl sulfate/polyacrylamide gel electrophoresis, and a spectrophotometric enzyme assay, we identified the secreted gamma-glutamyl transpeptidase of H pylori (HPGGT) as the factor responsible for inhibition of T-cell proliferation.

RESULTS

Mutagenesis of HPGGT in different H pylori strains completely abrogated this inhibitory effect. Recombinantly expressed HPGGT protein showed full antiproliferative activity. Site-directed mutagenesis and application of the GGT inhibitor acivicin revealed that inhibition of T cells depends on catalytic activity of HPGGT. Cell cycle analysis of human T cells indicated that HPGGT was necessary and sufficient to induce G(1) arrest. Reduced levels of c-Myc and phosphorylated c-Raf protein suggest the disruption of Ras-dependent signaling by HPGGT.

CONCLUSIONS

GGT is a novel immunosuppressive factor of H pylori inhibiting T-cell proliferation by induction of a cell cycle arrest in the G(1) phase.