Narrow-band imaging versus Lugol chromoendoscopy for esophageal squamous cell cancer screening in normal endoscopic practice: randomized controlled trial.

BACKGROUND: Narrow-band imaging (NBI) is as sensitive as Lugol chromoendoscopy to detect esophageal squamous cell carcinoma (SCC) but its specificity, which appears higher than that of Lugol chromoendoscopy in expert centers, remains to be established in general practice. This study aimed to prove the superiority of NBI specificity over Lugol chromoendoscopy in the detection of esophageal SCC and high grade dysplasia (HGD) in current general practice (including tertiary care centers, local hospitals, and private clinics). METHODS: This prospective randomized multicenter trial included consecutive patients with previous or current SCC of the upper aerodigestive tract who were scheduled for gastroscopy. Patients were randomly allocated to either the Lugol or NBI group. In the Lugol group, examination with white light and Lugol chromoendoscopy were successively performed. In the NBI group, NBI examination was performed after white-light endoscopy. We compared the diagnostic characteristics of NBI and Lugol chromoendoscopy in a per-patient analysis. RESULTS: 334 patients with history of SCC were included and analyzed (intention-to-treat) from 15 French institutions between March 2011 and December 2015. In per-patient analysis, sensitivity, specificity, positive and negative likelihood values were 100 %, 66.0 %, 21.2 %, and 100 %, respectively, for Lugol chromoendoscopy vs. 100 %, 79.9 %, 37.5 %, and 100 %, respectively, for NBI. Specificity was greater with NBI than with Lugol (P = 0.002). CONCLUSIONS: As previously demonstrated in expert centers, NBI was more specific than Lugol in current gastroenterology practice for the detection of early SCC, but combined approaches with both NBI and Lugol could improve the detection of squamous neoplasia.

CAD-CAP: a 25,000-image database serving the development of artificial intelligence for capsule endoscopy.

Background and study aims Capsule endoscopy (CE) is the preferred method for small bowel (SB) exploration. With a mean number of 50,000 SB frames per video, SBCE reading is time-consuming and tedious (30 to 60 minutes per video). We describe a large, multicenter database named CAD-CAP (Computer-Assisted Diagnosis for CAPsule Endoscopy, CAD-CAP). This database aims to serve the development of CAD tools for CE reading. Materials and methods Twelve French endoscopy centers were involved. All available third-generation SB-CE videos (Pillcam, Medtronic) were retrospectively selected from these centers and deidentified. Any pathological frame was extracted and included in the database. Manual segmentation of findings within these frames was performed by two pre-med students trained and supervised by an expert reader. All frames were then classified by type and clinical relevance by a panel of three expert readers. An automated extraction process was also developed to create a dataset of normal, proofread, control images from normal, complete, SB-CE videos. Results Four-thousand-one-hundred-and-seventy-four SB-CE were included. Of them, 1,480 videos (35 %) containing at least one pathological finding were selected. Findings from 5,184 frames (with their short video sequences) were extracted and delimited: 718 frames with fresh blood, 3,097 frames with vascular lesions, and 1,369 frames with inflammatory and ulcerative lesions. Twenty-thousand normal frames were extracted from 206 SB-CE normal videos. CAD-CAP has already been used for development of automated tools for angiectasia detection and also for two international challenges on medical computerized analysis.

Safety of Endoscopic Ultrasound-Guided Fine-Needle Aspiration for Pancreatic Solid Pseudopapillary Neoplasm Before Surgical Resection: A European Multicenter Registry-Based Study on 149 Patients.

OBJECTIVES: The results of only a few endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for pancreatic solid pseudopapillary neoplasm (SPN) have been published, and the safety of the procedure has never been investigated. Our study compared the recurrence rate in patients with and without preoperative EUS-FNA. METHODS: This European multicenter registry-based study was conducted in 22 digestive units, and retrospectively included all patients who underwent complete resection of a pancreatic SPN from 2000 to 2018. Patients with and without initial EUS-FNA were compared, and postsurgery recurrence and the associated risk factors were evaluated. RESULTS: A complete resection of a pancreatic SPN was performed in 149 patients (133 women, 89%), with a mean age of 34 (standard deviation, 14) years. There were no significant differences between the with (78 patients) and without (71 patients) EUS-FNA groups, except for age and tumor size and location.Preoperative EUS-FNA allowed pancreatic SPN diagnosis in 63/78 cases (81%). After a mean follow-up of 43 (standard deviation, 36) months, recurrence was noted in 4 patients (2.7%). Preoperative EUS-FNA was not correlated with recurrence, but an older age (P = 0.005) was significant. CONCLUSIONS: Preoperative EUS-FNA does not affect pancreatic SPN recurrence. In this series, old age was significantly correlated with recurrence.

Diagnostic value of CA19.9, circulating tumour DNA and circulating tumour cells in patients with solid pancreatic tumours.

BACKGROUND: The direct comparison of CA19.9, circulating tumour cells (CTCs) and circulating tumour DNA (ctDNA) using endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has never been performed for the diagnosis of solid pancreatic tumours (SPTs). METHODS: We included 68 patients with a SPT referred for EUS-FNA. CTCs were analysed using size-based platform and ctDNA using digital PCR. The sensitivity, specificity, negative and positive predictive values were evaluated for each marker and their combination. RESULTS: SPTs corresponded to 58 malignant tumours (52 pancreatic adenocarcinoma (PA) and 6 others) and 10 benign lesions. The sensitivity and specificity for PA diagnosis were 73% and 88% for EUS-FNA, 67% and 80% for CTC, 65% and 75% for ctDNA and 79% and 93% for CA19.9, respectively. The positivity of at least 2 markers was associated with a sensitivity and specificity of 78% and 91%, respectively. CtDNA was the only marker associated with overall survival (median 5.2 months for ctDNA+ vs 11.0 months for ctDNA-, P=0.01). CONCLUSIONS: CA19.9 alone and in combination with ctDNA and/or CTC analysis may represent an efficient method for diagnosing PA in patients with SPTs. Further studies including a larger cohort of patients with both malignant and benign lesions will be necessary to confirm these promising results.

Complete endoscopic sphincterotomy with vs. without large-balloon dilation for the removal of large bile duct stones: randomized multicenter study.

Background and study aims Endoscopic sphincterotomy plus large-balloon dilation (ES-LBD) has been reported as an alternative to endoscopic sphincterotomy for the removal of bile duct stones. This multicenter study compared complete endoscopic sphincterotomy with vs. without large-balloon dilation for the removal of large bile duct stones. This is the first randomized multicenter study to evaluate these procedures in patients with exclusively large common bile duct (CBD) stones. Methods Between 2010 and 2015, 150 patients with one or more common bile duct stones ≥ 13 mm were randomized to two groups: 73 without balloon dilation (conventional group), 77 with balloon dilation (ES-LBD group). Mechanical lithotripsy was subsequently performed only if the stones were too large for removal through the papilla. Endoscopic sphincterotomy was complete in both groups. Patients could switch to ES-LBD if the conventional procedure failed. Results There was no between-group difference in number and size of stones. CBD stone clearance was achieved in 74.0 % of patients in the conventional group and 96.1 % of patients in the ES-LBD group (P < 0.001). Mechanical lithotripsy was needed significantly more often in the conventional group (35.6 % vs. 3.9 %; P < 0.001). There was no difference in terms of morbidity (9.3 % in the conventional group vs. 8.1 % in the ES-LBD group; P = 0.82). The cost and procedure time were not significantly different between the groups overall, but became significantly higher for patients in the conventional group who underwent mechanical lithotripsy. The conventional procedure failed in 19 patients, 15 of whom underwent a rescue ES-LBD procedure that successfully cleared all stones. Conclusions Complete endoscopic sphincterotomy with large-balloon dilation for the removal of large CBD stones has similar safety but superior efficiency to conventional treatment, and should be considered as the first-line step in the treatment of large bile duct stones and in rescue treatment.Trial registered at ClinicalTrials.gov (NCT02592811).

A novel hemostatic powder for upper gastrointestinal bleeding: a multicenter study (the "GRAPHE" registry).

Background and study aims: The hemostatic powder TC-325 (Hemospray; Cook Medical, Winston-Salem, North Carolina, USA) has shown promising results in the treatment of upper gastrointestinal bleeding (UGIB) in expert centers in pilot studies. The aim of this study was to evaluate the feasibility and efficacy of TC-325 in a large prospective registry of use in routine practice. Patients and methods: The data of all patients treated with TC-325 were prospectively collected through a national registry. Outcomes were the immediate feasibility and efficacy of TC-325 application, as well as the rates of rebleeding at Day 8 and Day 30. Multivariate analysis was performed to determine predictive factors of rebleeding. Results: A total of 202 patients were enrolled and 64 endoscopists participated from 20 centers. TC-325 was used as salvage therapy in 108 patients (53.5 %). The etiology of bleeding was an ulcer in 75 patients (37.1 %), tumor in 61 (30.2 %), postendoscopic therapy in 35 (17.3 %), or other in 31 (15.3 %). Application of the hemostatic powder was found to be very easy or easy in 31.7 % and 55.4 %, respectively. The immediate efficacy rate was 96.5 %. Recurrence of UGIB was noted at Day 8 and Day 30 in 26.7 % and 33.5 %, respectively. Predictive factors of recurrence at Day 8 were melena at initial presentation and use of TC-325 as salvage therapy. Conclusion: These multicenter data confirmed the high rate of immediate hemostasis, excellent feasibility, and good safety profile of TC-325, which could become the treatment of choice in bleeding tumors or postendoscopic bleeding but not in bleeding ulcers where randomized studies are needed. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02595853).

Enteral delivery of proteins enhances the expression of proteins involved in the cytoskeleton and protein biosynthesis in human duodenal mucosa.

BACKGROUND: Amino acids are well known to be key effectors of gut protein turnover. We recently reported that enteral delivery of proteins markedly stimulated global duodenal protein synthesis in carbohydrate-fed healthy humans, but specifically affected proteins remain unknown. OBJECTIVE: We aimed to assess the influence of an enteral protein supply on the duodenal mucosal proteome in carbohydrate-fed humans. DESIGN: Six healthy volunteers received for 5 h, on 2 occasions and in random order, either an enteral infusion of maltodextrins alone (0.25 g · kg⁻¹ · h⁻¹) mimicking the fed state or maltodextrins with a protein powder (0.14 g proteins · kg⁻¹ · h⁻¹). Endoscopic duodenal biopsy specimens were then collected and frozen until analysis. A 2-dimensional polyacrylamide gel electrophoresis-based comparative proteomics analysis was then performed, and differentially expressed proteins (at least ±1.5-fold change; Student's t test, P < 0.05) were identified by mass spectrometry. Protein expression changes were confirmed by Western blot analysis. RESULTS: Thirty-two protein spots were differentially expressed after protein delivery compared with maltodextrins alone: 28 and 4 spots were up- or downregulated, respectively. Among the 22 identified proteins, 11 upregulated proteins were involved either in the cytoskeleton (ezrin, moesin, plastin 1, lamin B1, vimentin, and ß-actin) or in protein biosynthesis (glutamyl-prolyl-transfer RNA synthetase, glutaminyl-transfer RNA synthetase, elongation factor 2, elongation factor 1δ, and eukaryotic translation and initiation factor 3 subunit f). CONCLUSIONS: Enteral delivery of proteins altered the duodenal mucosal proteome and mainly stimulated the expression of proteins involved in cytoskeleton and protein biosynthesis. These results suggest that protein supply may affect intestinal morphology by stimulating actin cytoskeleton remodeling.

Radiofrequency ablation for the treatment of gastric antral vascular ectasia.

BACKGROUND AND STUDY AIMS: The traditional endoscopic treatment for gastric antral vascular ectasia (GAVE) is argon plasma coagulation, but results are not always positive. Radiofrequency ablation (RFA) is a new endoscopic therapy that may be an attractive option for the treatment of GAVE. The aim of this study was to assess the efficacy and safety of RFA for the treatment of GAVE. PATIENTS AND METHODS: This was an open-label, retrospective, case series study. The main outcome measures were number of red blood cell (RBC) packs transfused (transfusion requirement) and hemoglobin concentrations (g/dL) in the 6 months prior to and after RFA. Success was defined as a decrease in transfusion requirement in the 6 months after RFA compared with before treatment. RESULTS: A total of 24 patients underwent a mean of 1.8 ± 0.8 RFA sessions. No complications were reported. One patient was referred for additional argon plasma coagulation during follow-up. The mean number of RBC packs decreased in all 23 transfusion-dependent patients, from a mean of 10.6 ± 12.1 during the 6 months prior to RFA, to a mean of 2.5 ± 5.9 during the 6 months after RFA treatment (P < 0.001), and 15 patients (65.2 %) were weaned off transfusions completely. An increase in the hemoglobin concentration was reported in all patients after RFA (from 6.8 ± 1.4 g/dL to 9.8 ± 1.8 g/dL; P < 0.001). CONCLUSION: RFA for the treatment of GAVE seems feasible and safe, and significantly reduced the need for RBC transfusion and increased the hemoglobin level in this retrospective case series.

Diagnostic impact of routine colonoscopy following acute diverticulitis: A multicenter study in 808 patients and controls.

BACKGROUND: The diagnosis of acute diverticulitis is mainly based on clinical, biological and computed tomography (CT)-scan findings. Elective colonoscopy is recommended after medical treatment, to rule out another diagnosis and to detect associated conditions; however, the relevance of this recommendation has been questioned. PATIENTS AND METHODS: Between January 2005 and December 2011, we retrospectively identified in three referral centers the consecutive patients whom underwent a colonoscopy after the medical treatment of a CT scan-proven acute diverticulitis episode. We excluded from the analysis patients with haematochezia or recent change in bowel habits. Sex and age-matched asymptomatic patients undergoing a screening colonoscopy were chosen as a control group. We collected and compared the results of colonoscopy and histological findings in both groups. RESULTS: We matched 404 patients whom underwent a colonoscopy after an episode of acute diverticulitis with 404 control patients. Their mean age was 60.9 years, with 59% being women. Colorectal adenoma, advanced adenoma and cancer detection rates in acute diverticulitis patients were 12.1%, 2.7% and 0.25%, respectively; versus 14.6% (p = 0.35), 6.7% (p = 0.01) and 0.25% respectively, in control patients. CONCLUSIONS: Diagnosis rates for adenomas and for colorectal cancer during a colonoscopy scheduled after acute diverticulitis were similar than those of control patients undergoing a screening colonoscopy, while the detection rate of advanced adenomas was lower. We suggest that colonoscopy should be indicated only in selected patients, i.e. those presenting with reasonable doubt on initial CT-scan, those with alarm symptoms, and those with identified risk factors for colorectal cancer.

Enteral glutamine infusion modulates ubiquitination of heat shock proteins, Grp-75 and Apg-2, in the human duodenal mucosa.

Glutamine, the most abundant amino acid in the human body, plays several important roles in the intestine. Previous studies showed that glutamine may affect protein expression by regulating ubiquitin-proteasome system. We thus aimed to evaluate the effects of glutamine on ubiquitinated proteins in human duodenal mucosa. Five healthy male volunteers were included and received during 5 h, on two occasions and in a random order, either an enteral infusion of maltodextrins alone (0.25 g kg(-1) h(-1), control), mimicking carbohydrate-fed state, or maltodextrins with glutamine (0.117 g kg(-1) h(-1), glutamine). Endoscopic duodenal biopsies were then taken. Total cellular protein extracts were separated by 2D gel electrophoresis and analyzed by an immunodetection using anti-ubiquitin antibody. Differentially ubiquitinated proteins were then identified by liquid chromatography-electrospray ionization MS/MS. Five proteins were differentially ubiquitinated between control and glutamine conditions. Among these proteins, we identified two chaperone proteins, Grp75 and hsp74. Grp75 was less ubiquitinated after glutamine infusion compared with control. In contrast, hsp74, also called Apg-2, was more ubiquitinated after glutamine. In conclusion, we provide evidence that glutamine may regulate ubiquitination processes of specific proteins, i.e., Grp75 and Apg-2. Grp75 has protective and anti-inflammatory properties, while Apg-2 indirectly regulates stress-induced cell survival and proliferation through interaction with ZO-1. Further studies should confirm these results in stress conditions.

Impact of nutritional parameter variations during definitive chemoradiotherapy in locally advanced oesophageal cancer.

BACKGROUND: Undernutrition is frequently observed in patients with a locally advanced oesophageal carcinoma. However, variations of nutritional parameters during chemoradiotherapy have not been thoroughly investigated. AIM: To evaluate the characteristics and the impact of nutritional variations during treatment. METHODS: Weight loss, body mass index (BMI), serum albumin level and daily food intake at baseline and during treatment (T1=week 1; T2=week 5 or 8; T3=week 11) were retrospectively analyzed in 101 patients with oesophageal carcinoma. RESULTS: Significant variations occurred during chemoradiotherapy with a decrease in serum albumin level (p<0.001), body mass index (p<0.001) and weight (p<0.001). Response rate to treatment was significantly lower in patients with undernutrition at T1 (p=0.05), from T1 to T2 (p=0.01) and from T1 to T3 (p=0.04). Median overall survival was 25 months in patients with persistent undernutrition from T1 to T2 vs 42 months in wellnourished patients from T1 to T2 and those malnourished only at T1 or T2 (p=0.05). In responders, patients presenting with a lower weight or a lower food intake from T1 to T3 had worse survival (33 vs 59 months, p<0.001 and 29 vs 61 months, p=0.001, respectively). CONCLUSION: Significant variations of nutritional parameters occurred during chemoradiotherapy with a worse impact on response and survival.

Lack of correlation between morbid obesity and severe gastroesophageal reflux disease in candidates for bariatric surgery: results of a large prospective study.

The relationship between obesity and gastroesophageal reflux disease (GERD) is a subject of debate. In this large series of 250 morbidly obese patients, all candidates for bariatric surgery, we have shown the very low prevalence of severe GERD and neither Barrett's esophagus nor esophageal adenocarcinoma was detected. Moreover, no relationship was found between GERD and not only BMI but also abdominal diameter.

Enteral delivery of proteins stimulates protein synthesis in human duodenal mucosa in the fed state through a mammalian target of rapamycin-independent pathway.

BACKGROUND: Glutamine modulates duodenal protein metabolism in fasted healthy humans, but its effects in a fed state remain unknown. OBJECTIVE: We aimed to assess the effects of either glutamine or an isonitrogenous protein mixture on duodenal protein metabolism in humans in the fed state. DESIGN: Twenty-four healthy volunteers were randomly included in 2 groups. Each volunteer was studied on 2 occasions in a random order and received, during 5 h, either an enteral infusion of maltodextrins alone (0.25 g · kg⁻¹ · h⁻¹; both groups) that mimicked a carbohydrate fed state or maltodextrins with glutamine (group 1) or an isonitrogenous (22.4 mg N · kg⁻¹ · h⁻¹) protein powder (group 2). Simultaneously, a continuous intravenous infusion of ¹³C-leucine and ²H5-phenylalanine (both 9 µmol · kg⁻¹ · h⁻¹) was performed. Endoscopic duodenal biopsies were taken. Leucine and phenylalanine enrichments were assessed by using gas chromatography-mass spectrometry in duodenal proteins and the intracellular free amino acids pool to calculate the mucosal fractional synthesis rate (FSR). Proteasome proteolytic activities and phosphokinase expression were assessed by using specific fluorogenic substrates and macroarrays, respectively. RESULTS: The FSR and proteasome activity were not different after the glutamine supply compared with after maltodextrins alone. In contrast, the FSR increased (1.7-fold increase; P < 0.05) after protein-powder delivery without modification of total proteasome activity. The protein powder increased insulinemia, PI3 kinase, and erk phosphorylation but did not affect the mammalian target of rapamycin (mTOR) pathway and mitogen-activated protein kinase signal-integrating kinase 1 phosphorylation. A trend for an increase of eukaryotic translation initiation factor 4E phosphorylation was observed (P = 0.07). CONCLUSION: In the carbohydrate fed state, enteral proteins but not glutamine increased duodenal protein synthesis through an mTOR independent pathway in humans.

An enteral leucine supply modulates human duodenal mucosal proteome and decreases the expression of enzymes involved in fatty acid beta-oxidation.

Leucine is well known to regulate protein metabolism in muscle. We recently reported that enteral leucine infusion decreased proteasome activity in human duodenal mucosa and enhanced intestinal cell proliferation, but its effects on gut proteome remain unknown. Therefore, we aimed to assess the effects of an enteral leucine infusion on the whole proteome of duodenal mucosa. In this work, 5 healthy volunteers received for 5h, on 2 occasions and in random order, an enteral supply of maltodextrins (0.25 g kg(-1) h(-1)) or maltodextrins supplemented with leucine (0.035 g kg(-1) h(-1)). At the end of infusion, endoscopic duodenal biopsy samples were collected and analyzed by 2D-PAGE. Eleven protein spots were differentially and significantly (P<0.05) expressed in response to the leucine-supplemented maltodextrins compared with maltodextrins alone. Forty percent of identified proteins by mass spectrometry were located in mitochondria. Four proteins were involved in lipid metabolism: HADHA, ACADVL and CPT2 expressions were reduced, whereas FABP1 expression was increased. In addition, the expression of DHA kinase involved in glycerol metabolism was also downregulated. Finally, leucine supplementation altered the duodenal mucosal proteome by regulating the expression of several enzymes mainly involved in lipid metabolism. These results suggest that leucine supplementation may slowdown fatty acid beta-oxidation in human duodenal mucosa.

Role of toll like receptors in irritable bowel syndrome: differential mucosal immune activation according to the disease subtype.

BACKGROUND: The irritable bowel syndrome (IBS) is a functional gastrointestinal disorder whose pathogenesis is not completely understood. Its high prevalence and the considerable effects on quality of life make IBS a disease with high social cost. Recent studies suggest that low grade mucosal immune activation, increased intestinal permeability and the altered host-microbiota interactions that modulate innate immune response, contribute to the pathophysiology of IBS. However, the understanding of the precise molecular pathophysiology remains largely unknown. METHODOLOGY AND FINDINGS: In this study our objective was to evaluate the TLR expression as a key player in the innate immune response, in the colonic mucosa of IBS patients classified into the three main subtypes (with constipation, with diarrhea or mixed). TLR2 and TLR4 mRNA expression was assessed by real time RT-PCR while TLRs protein expression in intestinal epithelial cells was specifically assessed by flow cytometry and immunofluorescence. Mucosal inflammatory cytokine production was investigated by the multiplex technology. Here we report that the IBS-Mixed subgroup displayed a significant up-regulation of TLR2 and TLR4 in the colonic mucosa. Furthermore, these expressions were localized in the epithelial cells, opening new perspectives for a potential role of epithelial cells in host-immune interactions in IBS. In addition, the increased TLR expression in IBS-M patients elicited intracellular signaling pathways resulting in increased expression of the mucosal proinflammatory cytokines IL-8 and IL1ß. CONCLUSIONS: Our results provide the first evidence of differential expression of TLR in IBS patients according to the disease subtype. These results offer further support that microflora plays a central role in the complex pathophysiology of IBS providing novel pharmacological targets for this chronic gastrointestinal disorder according to bowel habits.

Factors associated with diagnosis of obscure gastrointestinal bleeding by video capsule enteroscopy.

BACKGROUND & AIMS: Capsule enteroscopy (CE) is the best noninvasive tool to explore the entire small bowel of patients with obscure gastrointestinal bleeding (OGIB); it has a diagnostic yield of 40%-80%. However, little is known about the factors associated with a diagnosis of OGIB by CE. METHODS: We analyzed data from 911 consecutive patients who underwent CE for OGIB from January 2004 to January 2010. Results from upper and lower gastrointestinal endoscopy examinations were negative in all patients. CE findings were recorded. Features of patients that were associated with diagnosis of OGIB by CE were identified by using logistic regression. RESULTS: Based on CE, 509 patients (56%) had a confirmed lesion responsible for the OGIB: 203 had disease of the small bowel (22%), 88 had ulcerations (10%), 70 had tumors (8%), 24 had varices (2%), 6 had diverticula (0.5%), and 118 had what appeared to be bleeding lesions of the esophagus or stomach (10.6%) or colon (2%). Factors independently associated with a diagnosis of OGIB by CE were age >60 years (odds ratio [OR], 1.2), male sex, history of overt bleeding (OR, 3.8), and current hospitalization (OR, 1.4). Women were less likely to be diagnosed with OGIB by CE (OR, 0.7). CONCLUSIONS: A history of overt bleeding is the factor most strongly associated with a diagnosis of OGIB by CE. Male sex, age >60 years, and inpatient status were also independent predictors of positive diagnosis by CE.

The expression and the cellular distribution of the tight junction proteins are altered in irritable bowel syndrome patients with differences according to the disease subtype.

OBJECTIVES: Recent studies have suggested that an increased intestinal permeability is involved in the pathophysilogy of irritable bowel syndrome (IBS). However, the differential expression of tight junctions (TJs) proteins according to IBS subtypes and symptoms remained unknown. The objective of this study was to study zonula occludens-1 (ZO-1), occludin, and claudin-1 in the colonic mucosa of patients with IBS. METHODS: Fifty IBS patients fulfilling the Rome III criteria and 31 controls were included. All types of IBS patients participated with predominant diarrhea (IBS-D, n=19), predominant constipation (IBS-C, n=14), constipation alternating with diarrhea (IBS-A, n=15), or unclassified (IBS-U, n=2). IBS symptom intensity was quantified on 10-cm Visual Analog Scale (VAS). TJ proteins (claudin-1, ZO-1, occludin) were quantified by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), western blot, while their localization was determined by immunofluorescence. RESULTS: ZO-1 and occludin expression was lower in IBS patients compared with controls, whereas only a trend for a decrease of claudin-1 was observed. The mRNA levels remained unaffected. In the subgroup analyses, occludin and claudin-1 expression was decreased in IBS-D patients but not in IBS-C and IBS-A patients. The subcellular distribution of these three proteins was altered in IBS-C and IBS-D patients. Occludin (r=0.40, P<0.01) and claudin-1 (r=0.46, P<0.01) expression was correlated with the duration of symptoms. The expression of occludin was lower in patients with an abdominal pain intensity higher than 6 on the VAS (P<0.05). CONCLUSIONS: Occludin and claudin-1 appeared markedly affected in IBS-D patients. In addition, our results suggest that alteration of TJ proteins may be involved in the initiation of IBS and contribute to visceral hypersensitivity.

Effects of an enteral glucose supply on protein synthesis, proteolytic pathways, and proteome in human duodenal mucosa.

BACKGROUND: Previous studies have shown that the glucose supply reduces postoperative insulin resistance and improves patient outcomes. However, the effects of luminal glucose on intestinal mucosal proteins remain unknown. OBJECTIVE: We aimed to assess the effects of an enteral glucose supply on protein synthesis, proteolytic pathways, and proteome in human duodenal mucosa. DESIGN: Twenty healthy volunteers received a 5-h enteral infusion of either saline or glucose (0.12 g · kg(-1) · h(-1)). Simultaneously, a continuous intravenous infusion of l-[1-(13)C]leucine (12 µmol · kg(-1) · h(-1)) was maintained until endoscopy. The duodenal mucosal protein fractional synthesis rate (FSR) was calculated from leucine enrichments assessed in protein and free amino acid pools by gas chromatography-mass spectrometry. Cathepsin D, calpains, and chymotrypsin-like proteasome mucosal activities were evaluated by using specific fluorogenic substrates. A 2-dimensional PAGE-based comparative proteomics analysis was also performed on additional duodenal mucosal biopsy samples to identify differentially expressed proteins. RESULTS: Duodenal mucosal protein FSR and protease activities were not affected by glucose infusion relative to saline. Nevertheless, the comparative proteomics analysis indicated that 10 protein spots were significantly differentially expressed (ie, at least ±1.5-fold modulated; Student's t test, P < 0.05) in response to the glucose infusion relative to saline. Of the 8 proteins identified by mass spectrometry, α-enolase, cytoplasmic aconitate hydratase, and glutathione S-transferase ω-1 were upregulated, whereas epoxide hydrolase 2 was downregulated. CONCLUSION: Enteral glucose supply affected neither duodenal mucosal protein FSR nor activities of mucosal proteases but altered the duodenal mucosal proteome by modulating the expression of several enzymes involved mainly in carbohydrate and xenobiotic metabolism. This trial is registered at clinicaltrials.gov as NCT00213551.