Location, morphology and invasiveness of lateral spreading tumors in the colorectum differ between two large cohorts from an eastern and western country

BACKGROUND AND STUDY AIMS

Data from Japanese series show that surface morphology of laterally spreading tumors (LST) in the colon identifies lesions with different incidence and pattern of submucosal invasion. Such data from western countries are scarce. We compared clinical and histological features of LST in a western country and an eastern country, with special interest on mucosal invasiveness of LST, and investigated the effect of clinical factors on invasiveness in both countries.

PATIENTS AND METHODS

Patients with LST lesions ≥20mm were included from a multicenter prospective registry in Spain and from a retrospective registry from the National Cancer Center Hospital East, Japan. The primary outcome was the presence of submucosal invasion in LST. The secondary outcome was the presence of high-risk histology, defined as high-grade dysplasia or submucosal invasion.

RESULTS

We evaluated 1102 patients in Spain and 663 in Japan. Morphological and histological characteristics differed. The prevalence of submucosal invasion in Japan was six-fold the prevalence in Spain (Prevalence Ratio PR=5.66; 95%CI: 3.96, 8.08), and the prevalence of high-risk histology was 1.5 higher (PR=1.44; 95%CI: 1.31, 1.58). Compared to the granular homogeneous type and adjusted by clinical features, granular mixed, flat elevated, and pseudo-depressed types were associated with higher odds of submucosal invasion in Japan, whereas only the pseudo-depressed type showed higher risk in Spain. Regarding high-risk histology, both granular mixed and pseudo-depressed were associated with higher odds in Japan, compared with only the granular mixed type in Spain.

CONCLUSION

This study reveals differences in location, morphology and invasiveness of LST in an eastern and a western cohort.

High incidence of advanced colorectal neoplasia during endoscopic surveillance in serrated polyposis syndrome

BACKGROUND

Serrated polyposis syndrome (SPS) has been associated with an increased risk of colorectal cancer (CRC). Accordingly, intensive surveillance with annual colonoscopy is advised. The aim of this multicenter study was to describe the risk of advanced lesions in SPS patients undergoing surveillance, and to identify risk factors that could guide the prevention strategy.

METHODS

From March 2013 to April 2015, 296 patients who fulfilled criteria I and/or III for SPS were retrospectively recruited at 18 centers. We selected patients in whom successful clearing colonoscopy had been performed and who underwent subsequent endoscopic surveillance. Advanced neoplasia was defined as CRC, advanced adenoma, or advanced serrated lesion that were ≥ 10 mm and/or with dysplasia. Cumulative incidence of advanced neoplasia was calculated and independent predictors of advanced neoplasia development were identified.

RESULTS

In 152 SPS patients a total of 315 surveillance colonoscopies were performed (median 2, range 1 - 7). The 3-year cumulative incidence of CRC and advanced neoplasia were 3.1 % (95 % confidence interval [CI] 0 - 6.9) and 42.0 % (95 %CI 32.4 - 51.7), respectively. Fulfilling both I + III criteria and the presence of advanced serrated lesions at baseline colonoscopy were independent predictors of advanced neoplasia development (odds ratio [OR] 1.85, 95 %CI 1.03 - 3.33, P  = 0.04 and OR 2.62, 95 %CI 1.18 - 5.81, P  = 0.02, respectively). During follow-up, nine patients (5.9 %) were referred for surgery for invasive CRC (n = 4, 2.6 %) or because of polyp burden (n = 5, 3.3 %). After total colectomy, 17.9 % patients developed advanced neoplasia in the retained rectum.

CONCLUSIONS

Patients with SPS have a substantial risk of developing advanced neoplasia under endoscopic surveillance, whereas CRC incidence is low. Personalized endoscopic surveillance based on polyp burden and advanced serrated histology could help to optimize prevention in patients with SPS.

[Management of new oral anticoagulants in gastrointestinal bleeding and endoscopy]

New oral direct anticoagulants agents are alternatives to warfarin for long-term anticoagulation in a growing number of patients that require long-term anticoagulation for atrial fibrillation, deep venous thrombosis and pulmonary embolism. These new agents with predictable pharmacokinetic and pharmacodynamics profiles offer a favorable global safety profile, but increased gastrointestinal bleeding compared to the vitamin K antagonists. Many gastroenterologists are unfamiliar and may be wary of these newer drugs, since Clinical experience is limited and no specific antidote is available to reverse their anticoagulant effect. In this article the risk of these new agents and, how to manage these agents in both the presence of acute gastrointestinal bleeding and in patients undergoing endoscopic procedures is reviewed.

[Endoscopic treatment of pancreatic pseudocyst. Practical features]

The initial treatment of most cases of pancreatic pseudocyst is endoscopic while surgery has been relegated to patients who cannot undergo this procedure for technical reasons, such as roux-en-Y roux reconstruction, or to those in whom other procedures have been unsuccessful. This change in the management of this entity is due to advances in therapeutic endoscopy (as a result of the development of guidelines, dilatation balloons, prostheses, safer techniques) as well as to better knowledge of the pathogenesis of pancreatic pseudocyst. The present study aims to describe endoscopic procedures for the drainage of pancreatic pseudocysts, particularly key technical features to ensure the maximum safety and effectiveness of this therapeutic technique.

Capsule endoscopy versus computed tomographic or standard angiography for the diagnosis of obscure gastrointestinal bleeding

BACKGROUND AND AIMS

Capsule endoscopy (CE) is superior to push enteroscopy and small bowel barium radiography in detecting the source of obscure GI bleeding. We now compared whether CE has a superior diagnostic yield than CT angiography (CTA) or standard mesenteric angiography (ANGIO) in patients with obscure GI bleeding.

METHODS

From June 2004 to October 2005, consecutive patients admitted for OGIB underwent both CTA and ANGIO, followed by CE, performed blindly by independent examiners within the next 7 days. The primary end point of the study was the diagnostic yield for each technique, defined as the frequency of detection of lesions with a high probability of bleeding.

RESULTS

Twenty-eight patients (16 men and 12 women, mean age 74 +/- 2 yr) with OGIB (overt bleeding in 20 cases and chronic occult in 8) were prospectively evaluated. CTA or standard angiography could be performed in 25 of 28 patients (applicability 86%), because of contrast allergy (1 patient) and chronic renal failure (2 patients). A source of bleeding was detected by CE in a greater proportion of patients, 72% (18 of 25, 95% CI 50.6-87.9%), than CTA, 24% (6 of 25, 95% CI 9.4-45.1%, P= 0.005 vs CE), or ANGIO, 56% (14 of 25, 95% CI 34.9-75.6%, P= NS). Similarly, CE was able to diagnose 100% of patients diagnosed by CTA and 86% of patients diagnosed by ANGIO. Moreover, CE was positive in 12 of 19 (63%) negative cases on CTA and in 6 of 11 (55%) negative cases on ANGIO. As a result of the CE findings, therapeutic intervention was undertaken in 9 of 19 (47%) patients with positive results.

CONCLUSION

CE detects more lesions than CTA or standard mesenteric angiography in patients with obscure GI bleeding and has a therapeutic impact in almost half of the patients with positive findings.

[Massive hemorrhage due to nodular hyperplasia of Brunner's glands in antiphospholipid syndrome]

Gastrointestinal hemorrhage is an exceptional complication of antiphospholipid syndrome and most reported cases are secondary to ischemic lesions. Brunner's gland hyperplasia is an infrequent and usually asymptomatic condition that has been associated with chronic renal failure. We report a patient with primary antiphospholipid syndrome who, after mechanic heart valve replacement and while in a state of drug-induced anticoagulation, experienced a life-threatening upper gastrointestinal hemorrhage due to nodular hyperplasia of Brunner's glands. This entity may be considered in the differential diagnosis of upper gastrointestinal bleeding in patients with antiphospholipid syndrome, most of whom are treated with oral anticoagulatory drugs, and particularly in patients with chronic renal failure.

Colitis induces CRF expression in hypothalamic magnocellular neurons and blunts CRF gene response to stress in rats

We investigated hypothalamic neuronal corticotropin-releasing factor (CRF) gene expression changes in response to visceral inflammation induced by 2,4,6-trinitrobenzenesulfonic acid (TNB) and acute stress. Seven days after TNB, rats were subjected to water-avoidance stress (WAS) or restraint for 30 min and euthanized. Hypothalamic CRF primary transcripts (heteronuclear RNA, hnRNA) and CRF and arginine vasopressin (AVP) mRNAs were assessed by in situ hybridization. Antisense (35)S-labeled cRNA probes against CRF mRNA intronic and exonic sequences and an oligonucleotide probe against the AVP mRNA were used. TNB induced macroscopic lesions and a fivefold elevation in myeloperoxidase activity in the colon. Colitis increased CRF hnRNA and mRNA signals in the magnocellular part of the paraventricular nucleus of the hypothalamus (PVN) and supraoptic neurons, whereas AVP mRNA was not altered. Colitis did not modify CRF hnRNA signal in the parvocellular part of the PVN (pPVN), plasma corticosterone, and serum osmolarity levels. However, CRF hnRNA expression in the pPVN and the rise in corticosterone and defecation induced by WAS or restraint were blunted in colitic rats. These data show that colitis upregulates CRF gene synthesis in magnocellular hypothalamic neurons but dampens CRF gene transcription in the pPVN and plasma corticosterone responses to environmental acute stressors.

A multicenter, randomized, clinical trial of hormonal therapy in the prevention of rebleeding from gastrointestinal angiodysplasia

BACKGROUND & AIMS

The efficacy of hormonal therapy for recurrent bleeding from gastrointestinal angiodysplasia remains uncertain. We investigated the efficacy of long-term estrogen-progestagen therapy in the prevention of rebleeding from gastrointestinal angiodysplasia.

METHODS

Seventy-two noncirrhotic patients bleeding from gastrointestinal angiodysplasia confirmed by endoscopy or angiography were randomized to receive in double-blind conditions treatment with ethinylestradiol (0.01 mg) plus norethisterone (2 mg) (1 tablet/d), or placebo (1 tablet/d) for a minimum period of 1 year (range: 1-2 years).

RESULTS

Four patients could not be assessed because they did not attend the first follow-up visit. Failure of treatment occurred in 13 of 33 (39%) patients in the treatment group and in 16 of 35 (46%) patients in the placebo group (P = NS). No significant differences between groups were found according to number of bleeding episodes (0.7 +/- 1.0 vs. 0.9 +/- 1.5) and transfusional requirements (0.9 +/- 1.9 vs. 0.7 +/- 1.5 units). Treatment received was not an independent predictor for rebleeding prevention in the multivariate regression analysis. Severe adverse events (2 vs. 1) and mortality (0 vs. 1 patient, respectively) were similar between the treatment and placebo groups.

CONCLUSIONS

Continuous estrogen-progestagen treatment is not useful in the prevention of rebleeding from gastrointestinal angiodysplasia.

Accuracy of helical computed tomographic angiography for the diagnosis of colonic angiodysplasia

BACKGROUND & AIMS

The diagnosis of colonic angiodysplasia is often challenging and relies on endoscopy or catheter angiography. We investigated whether computed tomographic angiography (CTA) contributes to the diagnosis of colonic angiodysplasia.

METHODS

Twenty-eight patients with suspected bleeding from colonic angiodysplasia were prospectively evaluated. Gastrointestinal bleeding was investigated by colonoscopy plus visceral angiography and by CTA. The level of agreement between CTA and the former procedures was determined.

RESULTS

CTA images of diagnostic quality were obtained in 26 patients. Eighteen patients were diagnosed with colonic angiodysplasia by colonoscopy plus visceral angiography, and 14 by CTA (kappa = 0.68; P < 0.001). Sensitivity, specificity, and positive predictive values of CTA for detection of colonic angiodysplasia were 70%, 100%, and 100%, respectively. CTA signs including accumulation of vessels in the colonic wall, early filling vein, and supplying enlarged artery were present in 55%, 50%, and 22% of cases, respectively. None of these signs were present in the 8 patients with obscure gastrointestinal bleeding and negative diagnostic investigation of the digestive tract.

CONCLUSIONS

CTA is a sensitive, specific, well-tolerated, and minimally invasive tool for the diagnosis of colonic angiodysplasia.

Helicobacter pylori eradication prevents recurrence from peptic ulcer haemorrhage

BACKGROUND

Successful eradication of Helicobacter pylori infection clearly modifies the natural history of peptic ulcer disease and prevents further recurrences of duodenal and gastric ulcers. However, there are few prospective studies about actual rates of rebleeding after H. pylori eradication, a highly relevant aspect of management as re-infection, relapse of ulcer disease for other reasons (i.e. anti-inflammatory agents) or idiopathic ulcers unrelated to H. pylori may develop and cause further bleeding episodes.

OBJECTIVE

To determine the incidence of bleeding episodes after eradication of H. pylori infection in patients who had bled from an H. pylori-positive peptic ulcer.

PARTICIPANTS AND INTERVENTIONS

H. pylori-positive patients who bled from a gastric or duodenal ulcer were treated with appropriate triple and/or quadruple therapy. H. pylori eradication was confirmed by urea breath test 4 weeks after treatment. Patients received no further treatment but were followed clinically and additional urea breath tests were performed every 6 months. Endoscopy with antral and corpus biopsies and urea breath test were repeated as soon as patients manifested any dyspeptic symptoms that might signal recurrence.

RESULTS

A total of 103 patients with bleeding duodenal ulcer were included in the study; H. pylori was successfully eradicated in 93 of these patients, who were followed for a median interval of 27 months. The yearly re-infection rate was calculated to be 0.6%. There were no instances of rebleeding in any patients during the follow-up period.

CONCLUSIONS

Even after prolonged follow-up, successful H. pylori eradication prevents rebleeding.

Somatostatin plus isosorbide 5-mononitrate versus somatostatin in the control of acute gastro-oesophageal variceal bleeding: a double blind, randomised, placebo controlled clinical trial

BACKGROUND

Variceal bleeding is a severe complication of portal hypertension. Somatostatin reduces portal pressure by decreasing splanchnic blood flow, and nitrates by diminishing intrahepatic resistance. Experimental studies have shown that the combination of somatostatin and nitrates has an additive effect in decreasing portal pressure.

AIM

To compare the therapeutic efficacy of either intravenous infusion of somatostatin plus oral isosorbide 5-mononitrate or somatostatin alone in gastro-oesophageal variceal bleeding associated with liver cirrhosis.

METHODS

A unicentre, double blind, placebo controlled, clinical trial was conducted. Sixty patients bleeding from oesophageal or gastric varices were randomised to receive intravenous infusion of somatostatin (250 microg/hour) plus oral isosorbide 5-mononitrate (40 mg/12 hours) (group I) or somatostatin infusion plus placebo (group II) for 72 hours.

RESULTS

The two groups of patients had similar clinical, endoscopic, and haematological characteristics. Control of bleeding was achieved in 18 out of 30 patients (60%) in group I and 26 out of 30 patients (87%) in group II (p<0.05). There was no significant difference in mean transfusion requirements between the two groups: 2.6 (2.2) v 1.8 (1.6) respectively; means (SD). Mortality and side effects were similar in the two groups, but development of ascites was higher in group I (30%) than in group II (7%) (p<0.05).

CONCLUSION

In cirrhotic patients with acute gastro-oesophageal variceal bleeding, addition of isosorbide 5-mononitrate to somatostatin does not improve therapeutic efficacy, induces more adverse effects, and should not be used.

Characterisation of immune mediator release during the immediate response to segmental mucosal challenge in the jejunum of patients with food allergy

BACKGROUND

Food allergy is a common complaint among patients with a broad spectrum of abdominal and extra-abdominal symptoms that must be distinguished from other more common non-immunological food intolerances.

AIMS

To investigate whether human intestinal hypersensitivity reactions are associated with detectable release of inflammatory mediators from activated cells, which may serve as a biological marker of true allergic reactions.

PATIENTS/METHODS

In eight patients with food allergy and seven healthy volunteers, a closed-segment perfusion technique was used to investigate the effects of jejunal food challenge on luminal release of tryptase, histamine, prostaglandin D(2), eosinophil cationic protein, peroxidase activity, and water flux.

RESULTS

Intraluminal administration of food antigens induced a rapid increase in intestinal release of tryptase, histamine, prostaglandin D(2), and peroxidase activity (p<0.05 v basal period) but not eosinophil cationic protein. The increased release of these mediators was associated with a notable water secretory response.

CONCLUSIONS

These results suggest that human intestinal hypersensitivity reactions are characterised by prompt activation of mast cells and other immune cells, with notable and immediate secretion of water and inflammatory mediators into the intestinal lumen. Analysis of the profile of markers released into the jejunum after food provocation may be useful for the objective diagnosis of food allergy.

Mechanisms underlying the anti-inflammatory actions of central corticotropin-releasing factor

Immune activation of hypothalamic corticotropin-releasing factor (CRF) provides a negative feedback mechanism to modulate peripheral inflammatory responses. We investigated whether central CRF attenuates endothelial expression of intercellular adhesion molecule 1 (ICAM-1) and leukocyte recruitment during endotoxemia in rats and determined its mechanisms of action. As measured by intravital microscopy, lipopolysaccharide (LPS) induced a dose-dependent increase in leukocyte rolling, adhesion, and emigration in mesenteric venules, which was associated with upregulation of endothelial ICAM-1 expression. Intracisternal injection of CRF abrogated both the increased expression of ICAM-1 and leukocyte recruitment. Intravenous injection of the specific CRF receptor antagonist astressin did not modify leukocyte-endothelial cell interactions induced by a high dose of LPS but enhanced leukocyte adhesion induced by a low dose. Blockade of endogenous glucocorticoids but not alpha-melanocyte-stimulating hormone (alpha-MSH) receptors reversed the inhibitory action of CRF on leukocyte-endothelial cell interactions during endotoxemia. In conclusion, cerebral CRF blunts endothelial upregulation of ICAM-1 and attenuates the recruitment of leukocytes during endotoxemia. The anti-inflammatory effects of CRF are mediated by adrenocortical activation and additional mechanisms independent of alpha-MSH.

Increased expression of angiogenic factors in human colonic angiodysplasia

OBJECTIVE

Angiodysplasia of the colon is a distinct vascular abnormality characterized by focal accumulation of ectatic vessels in the mucosa and submucosa. To investigate whether angiogenesis contributes to the pathogenesis of human colonic angiodysplasia, we examined the expression of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF), and its endothelial cell receptors flt-1 and KDR.

METHODS

Immunohistochemistry was performed in sections of specimens obtained from 18 patients with colonic angiodysplasia and from eight patients with colon cancer and its adjacent, histologically normal margins of resection. We used affinity-purified rabbit polyclonal antibodies and a streptoavidin-biotin peroxidase method.

RESULTS

We detected strong immunoreactivity for vascular endothelial growth factor, homogeneously distributed in the endothelial lining of blood vessels of all sizes in 16 (89%) specimens of colonic angiodysplasia and in seven (88%) patients with colon cancer. In contrast, very limited immunoreactivity was found in normal colon. Vascular staining for flt-1 was observed in eight (44%) and one (12.5%) of the colonic angiodysplasia or colon cancer specimens, respectively, but not in normal colon. Vascular immunoreactivity for basic fibroblast growth factor was observed in seven (39%) specimens from patients with colonic angiodysplasia, whereas either very limited or no immunostaining was found in sections from specimens of patients with colon cancer and its normal margins.

CONCLUSIONS

In human colonic angiodysplasia, increased expression of angiogenic factors is likely to play a pathogenic role.

The impact of delaying gastric emptying by either meal substrate or drug on the [13C]-urea breath test

OBJECTIVE

Optimal [13C]-urea breath test (UBT) conditions for diagnosis of Helicobacter pylori infection are still being fine-tuned. In the present study we investigated the impact of delaying gastric emptying by different meal substrates or L-DOPA, a drug known to induce gastric stasis, on the performance of the [13C]-UBT.

METHODS

A total of 115 patients participated in the study. On two consecutive days, participants ingested [13C]-urea (100 mg) 10 min after either 270 ml of a mixed formula meal (1 Kcal/ml) or an equivalent amount of tap water. In 11 participants two additional tests were performed with or without oral 500 mg L-DOPA given 30 min before [13C]-urea load. The 13C/12C ratio in a basal breath sample was compared with ratios in samples collected 30 and 60 min after [13C]-urea. Histological assessment of H. pylori presence in antral biopsy served as reference standard.

RESULTS

Formula UBT showed excellent specificity (100% at 30 and 60 min) and good sensitivity (97% at both time intervals), whereas water UBT had the same specificity but slightly lower sensitivity (94% at 30 min and 73% at 60 min). In formula UBT, 13C/12C ratios were higher at 60 min than at 30 min (21.7+/-2 vs 17.7+/-1.8 per thousand respectively, p < 0.01, whereas in water UBT 13C/12C ratios were higher at 30 min than at 60 min (13.9+/-1.5 vs 8.4+/-0.09 per thousand respectively, p < 0.01). Pretreatment with L-DOPA did not modify either the sensitivity or the specificity of the UBT.

CONCLUSIONS

The performance of the [13C]-urea with a formula meal may not be improved by pharmacologically delaying gastric emptying. A short, water-based test may be a sensible approach to worldwide standardization of the [13C]-UBT for H. pylori infection.

[The attitude of primary health care physicians in the metropolitan area of Barcelona about the diagnosis and treatment of Helicobacter pylori infection in gastroduodenal diseases]

AIM

To evaluate the attitude of primary health care physicians versus the diagnosis and treatment of infection by Helicobacter pylori in patients with dyspepsia and gastroduodenal ulcer.

DESIGN

An observational, transversal study was performed by a self administered questionnaire from June to October, 1997.

PARTICIPANTS

Primary health care physicians from 38 reformed Medical Centers in the metropolitan area of Barcelona were included in the study.

RESULTS

Of the 359 doctors to whom the questionnaire was sent, 283 responded (78.8%). In a patient with dyspepsia 95.4% would first request endoscopy. If they knew of the presence of infection by Helicobacter pylori 96.1% would administer eradication treatment in patients with gastric and duodenal ulcer and 15% would also do so if the endoscopy were normal. If the presence of infection by Helicobacter pylori were unknown in a patient with gastroduodenal ulcer, 65.3% would treat with anti-H2 or proton pump inhibitors associated with a diagnostic test of infection by Helicobacter pylori. If the physician decided to carry out eradication treatment of Helicobacter pylori infection, 98.6% would use one of the regimes recommended by different scientific societies. If confirmation of eradication of Helicobacter pylori infection were requested, 89% would do so one and three months after completion of treatment. In patients with gastric ulcer, 69.3% would request endoscopy on completion of treatment. The percentage of physicians specialized in Family and Community Medicine who would carry out eradication treatment in patients with duodenal ulcer and Helicobacter pylori infection and who would request endoscopies in patients with dyspepsia was found to be statistically significant in comparison with physicians without this specialty.

CONCLUSIONS

The attitude of primary care physicians in the metropolitan area of Barcelona with regard to the diagnosis and treatment of infection by Helicobacter pylori in gastroduodenal diseases largely reflects the recommendations recently made by several scientific societies. In general there are no significant differences with respect to this attitude in regard to the age and sex of the physician, although their training was found to influence in some of the responses analyzed.

[Gastric ulcers as the only manifestation of infection by cytomegalovirus in immunocompetent patients]

Gastritis is an infrequent manifestation of infection by cytomegalovirus (CMV) in a healthy host. This complication is usually associated to a mononucleosic syndrome during the course of a disseminated infection. Macroscopically, it presents with edema and mucosal congestion, multiple erosions or ulcers. Histologic examination of the endoscopic biopsies allows the etiologic diagnosis to be established in most cases. In immunocompetent patients the clinical course of gastritis by CMV is usually self-limited. We herein present two immunocompetent patients with gastric ulcerous disease as the only manifestation of CMV infection. Both patients required antiviral treatment due to refractoryness to the antisecretor treatment and one case evolved to pyloric stenosis requiring surgery.

Release of mast cell mediators into the jejunum by cold pain stress in humans

BACKGROUND & AIMS

The central nervous system regulates gut functions via complex interactions between the enteric nervous and immune systems. The aim of this study was to investigate whether mast cell mediators are released into the human jejunal lumen during stress.

METHODS

A closed-segment perfusion technique was used to investigate jejunal release of tryptase, histamine, prostaglandin D2, and water flux in response to the cold pressor test in 8 healthy subjects and 9 patients with food allergy. In 6 food-allergic patients, jejunal biochemical responses to cold pain stress were compared with those induced by food intraluminal challenge.

RESULTS

Cold pain stress elevated heart rate and blood pressure and increased luminal release of mast cell mediators and jejunal water secretion in both groups. Stress-induced release of tryptase and histamine, but not of prostaglandin D2 and water flux, was greater in food-allergic patients than in healthy volunteers. In food-allergic patients, jejunal biochemical responses induced by cold pain stress were similar to those induced by antigen challenge.

CONCLUSIONS

These results show the ability of the central nervous system to modulate intestinal mast cell activity and suggest that mast cells have a role in stress-related gut dysfunction.

Regulation of intestinal mast cells and luminal protein release by cerebral thyrotropin-releasing hormone in rats

BACKGROUND & AIMS

Intestinal mast cell activity is modulated by the central nervous system, but the mechanisms are not well established. The aim of this study was to investigate whether cerebral thyrotropin-releasing hormone (TRH) activates intestinal mast cells and to elucidate the mechanisms involved, specifically, the contribution of mast cells to vagally stimulated luminal protein release.

METHODS

In anesthetized rats, mast cell activation was assessed by measuring the release of the specific mucosal rat mast cell protease II (RMCP II) and prostaglandin (PG) D2 into the intestinal lumen. Luminal protein release was measured as an index of epithelial permeability to macromolecules.

RESULTS

Intracisternal injection of the TRH analogue RX 77368 (30 ng) induced a transient increase in intestinal release of RMCP II and PGD2 that was abolished by dox-antrazole. RX 77368-stimulated RMCP II release was also abolished by vagotomy and reduced by atropine by 65%. However, both systemic capsaicin and indo-methacin enhanced RMCP II release. RX 77368-stimulated luminal protein release was abolished by vagotomy and reduced by doxantrazole.

CONCLUSIONS

Central vagal activation by TRH stimulates intestinal mast cell secretion, in part via peripheral muscarinic receptors, and is modulated by PGs and capsaicin-sensitive afferent innervation. Intestinal mast cell activation contributes to the TRH analogue-stimulated luminal protein release.

Central vagal activation by an analogue of TRH stimulates gastric nitric oxide release in rats

In the stomach nitric oxide (NO) appears to be involved in vagally induced cholinergic vasodilation and nonadrenergic, noncholinergic relaxation of the fundus. We investigated whether central vagal activation by intracisternal injection of a thyrotropin-releasing hormone (TRH) analogue stimulates gastric NO release in anesthetized rats. To quantitate gastric NO production, the luminal release of NO breakdown products, nitrite (NO2-) and nitrate (NO3-), were measured by the Griess method. Intracisternal injection of RX-77368 (30-300 ng) dose dependently stimulated gastric NO2- and NO3- release (P < 0.05) along with a significant acid secretory response (P < 0.05). The specific inhibitor of NO synthesis, NG-nitro-L-arginine methyl ester (10 mg/kg ip), completely blocked gastric luminal NO2- and NO3- release without affecting the acid secretory response to the highest dose of RX-77368. Either bilateral cervical vagotomy, hexamethonium (15 mg/kg ip), or atropine (1 mg/kg ip) abolished both gastric luminal release of NO-derived metabolites and the acid secretory responses to RX-77368. These results indicate that intracisternal injection of RX-77368 stimulates gastric release of NO through vagal nicotinic pathways and peripheral activation of muscarinic receptors. These findings provide evidence for central nervous system regulation of NO-mediated functions in the rat stomach through TRH-sensitive vagal pathways.

[Estrogen and progestagen treatment in digestive hemorrhage caused by vascular malformations]

The efficacy of an association of estrogens and progestagens in the treatment of gastrointestinal bleeding by angiodysplasia was analyzed. Thirty-three patients with gastrointestinal bleeding due to vascular malformations were admitted from January 1986 to December 1993. Fifteen of the 33 patients were submitted to surgical or endoscopic treatment. The remaining 18 patients underwent daily oral treatment with a combination of estrogens-progestagens containing 2.5 mg of lynestrenol and 0.075 mg of mestranol. One patient presented a venous thrombosis leading to suppression of treatment at one month of initiation. The 17 remaining patients were treated for a mean of 22 +/- 4 months (range: 3-60). During treatment 13 of the 17 patients (76%) did not present evidence of hemorrhage. Likewise, the number of hemorrhagic episodes per year decreased from 4.4 +/- 1.2 prior to treatment to 0.7 +/- 0.5 during treatment (p < 0.05) with transfusional requirements decreasing from 7.9 +/- 2.8 erythrocyte concentrates per year prior to treatment to 1.2 +/- 1.0 during treatment (p < 0.05). In conclusion, the combined treatment with estrogens and progestagens prevents recurrence of gastrointestinal bleeding by angiodysplasia.

Role of vagal and splanchnic capsaicin-sensitive afferents in enterogastric inhibition of acid secretion in rats

The role of capsaicin-sensitive afferent innervation and neural pathways involved in the enterogastric inhibition of gastric acid secretion by luminal acid was investigated in urethan-anesthetized rats. Intestinal perfusion with graded concentrations of HCl (50, 75, and 100 mM) for 1 h dose dependently inhibited both thyrotropin-releasing hormone (TRH) analogue- and pentagastrin-stimulated acid output (P < 0.01). The inhibitory effect of intestinal perfusion with HCl (100 mM) on pentagastrin-stimulated acid secretion was blocked by bilateral vagotomy, whereas celiac ganglionectomy had no effect. Systemic capsaicin pretreatment (125 mg/kg sc) reduced the antisecretory effects of luminal acid on both TRH analogue- and pentagastrin-stimulated acid secretion. Neither selective perivagal nor selective periceliac capsaicin treatments (1% solution) modified the antisecretory effect of intestinal perfusion with HCl (75 mM) on TRH analogue-stimulated acid secretion. However, combined selective perivagal plus periceliac capsaicin treatment reduced it to the same extent as systemic capsaicin treatment. We conclude that enterogastric inhibition of acid secretion by luminal acid in urethan-anesthetized rats is mediated by extrinsic reflexes involving both vagal and splanchnic capsaicin-sensitive afferent fibers.

Interleukin-1 receptor antagonist does not prevent endotoxin-induced inhibition of gastric acid secretion in rats

The underlying mechanisms involved in endotoxin-induced inhibition of gastric acid secretion were investigated in conscious rats with pylorus ligation for 2 hr. Intraperitoneal injection of endotoxin (0.1, 1, and 5 micrograms/rat) inhibited gastric acid output by 31%, 80%, and 84% respectively. Intraperitoneal endotoxin (1 microgram/rat) -induced inhibition of gastric acid secretion was not altered by pretreatment with the interleukin-1 receptor antagonist, IL-1RA, indomethacin, naloxone, or capsaicin. Treatments were injected peripherally at doses previously shown to antagonize the antisecretory effect of exogenous interleukin-1 beta, to inhibit prostaglandin synthesis in the stomach and brain, to block opiate receptors, and to alter functioning of unmyelinated afferent nerve fibers. These results indicate that the antisecretory effect of endotoxin can be expressed by factors other than interleukin-1, prostaglandins, or opioid peptides that do not require the integrity of capsaicin-sensitive afferent pathways.

Central interleukin-1 beta-induced inhibition of acid secretion in rats: specificity of action

It is well established that IL-1 beta acts in the brain to potently inhibit gastric acid secretion in pylorus-ligated rats. The present study was designed to further investigate the specificity and mechanisms of the centrally mediated antisecretory action of IL-1 beta in conscious rats. Intracerebroventricular injection of IL-1 beta (100 ng) decreased acid secretion in pylorus-ligated rats and inhibited basal and pentagastrin-stimulated acid secretion in rats with chronic gastric fistula. The antisecretory effect of IL-1 beta (100 ng) injected into the lateral ventricle of pylorus ligated rats was completely reversed by prior intracerebroventricular injection of the IL-1 receptor antagonist, IL-1ra, (100 micrograms). Peripheral administration of the somatostatin monoclonal antibody, CURE.S6, did not modify intracisternal IL-1 beta-induced inhibition of acid secretion in pylorus ligated rats. IL-6 and tumor necrosis factor-alpha (100 ng) injected intracisternally did not influence gastric acid secretion in pylorus-ligated rats. These data show that IL-1 beta action in the CNS is mediated through interaction with specific IL-1 receptors and is selective to this cytokine. IL-1 beta antisecretory action can be observed under basal and pentagastrin-stimulated conditions and is independent from somatostatin release in the periphery.

Potent inhibition of gastric acid secretion and ulcer formation by centrally and peripherally administered interleukin-1

IL-1 beta is one of the most potent centrally acting inhibitors of gastric acid secretion in rats. Sites of action have been located in the anterior/preoptic area and paraventricular nucleus of the hypothalamus where other biological activities of IL-1 have also been described. IL-1 beta action is, so far, quite unique to this cytokine and its action is not reproduced by IL-2 or TNF alpha. The IL-1 effect involves prostaglandin pathways and is unrelated to CRF. Similarly, systemic injection of IL-1 induces a long lasting inhibition of acid secretion through prostaglandin-dependent mechanisms. Several findings support the possibility that the effect of systemic IL-1 can be CNS-mediated and/or exerted at the periphery through local release of PG in the stomach. Exogenous IL-1 given into either the circulation or the cerebrospinal fluid also inhibits gastric injury induced by a variety of experimental models (stress, aspirin, ethanol). Such a protective effect is mediated through the inhibition of acid secretion and prostaglandin release, although other mechanisms may also contribute. Whether endogenously released IL-1 beta exerts a protective role in the gastric mucosa is still to be investigated.

Interleukin-1 beta acts at hypothalamic sites to inhibit gastric acid secretion in rats

It has been established that interleukin-1 beta (IL-1 beta) injected into the cerebrospinal fluid inhibits gastric acid secretion in rats. Brain sites of action of IL-1 beta were investigated in conscious rats implanted unilaterally with chronic hypothalamic cannula. Gastric acid secretion was monitored 2 h after pylorus ligation. Human recombinant IL-1 beta (10 ng) microinjected into the medial preoptic area, anterior hypothalamus, and paraventricular nucleus inhibited gastric acid secretion by 76-83%. IL-1 beta microinjected into the ventromedial hypothalamus and other hypothalamic sites outside of responsive sites had no effect. IL-1 beta inhibitory action in the medial preoptic area was dose related (0.1-10 ng), prevented by indomethacin (5 mg/kg ip), and mimicked by prostaglandin E2. These results show that IL-1 beta acts in the medial preoptic area/anterior hypothalamus and paraventricular nucleus to inhibit acid secretion in pylorus-ligated rats and that IL-1 beta action is likely to involve prostaglandin E2.

Potent inhibition of gastric acid secretion by intravenous interleukin-1 beta and -1 alpha in rats

The influence of human and rat recombinant interleukin-1 (hIL-1 beta and -1 alpha and rIL-1 beta) on acid secretion was investigated in conscious pylorus-ligated rats. Intravenous injection of either hIL-1 beta, hIL-1 alpha or rIL-1 beta dose dependently inhibited gastric acid output with an ED50 of 0.05 microgram, 0.5 microgram and 2.2 micrograms, respectively. The antisecretory action of IL-1 beta was associated with an increase in circulating levels of gastrin. hIL-1 beta-induced inhibition of acid secretion was dose dependently reversed by peripheral injection of the IL-1 receptor antagonist, IL-RA, with a dose ratio of 1:10(3) for complete reversal. The inhibitory effect of hIL-1 beta was blocked by indomethacin and was not modified by IV injections of the CRF receptor antagonist, alpha-helical CRF(9-41), or the monoclonal somatostatin antibody CURE.S6, or by systemic capsaicin pretreatment. These results show that systemic hIL-1 beta-induced inhibition of gastric acid secretion is mediated through IL-1 receptors and prostaglandin pathways, and does not involves CRF receptors, afferent fibers, or changes in circulating gastrin or somatostatin levels.

Role of central prostaglandin E2 in the regulation of gastric acid secretion in the rat

The central action of prostaglandin E2 (PGE2) on gastric acid secretion was investigated in rats by comparing the effects of intracisternal (i.ci.) and i.v. administration of PGE2 and the influence of i.ci. injection of indomethacin on acid secretion and PGE2 generation in the brain and stomach. I.ci. injections of PGE2 (1-10 micrograms) or the stable analog, 16,16-dimethyl PGE2, (0.01-0.1 micrograms) induced a dose dependent inhibition of baclofen-stimulated gastric acid secretion by 0-82% and by 7-87% respectively. I.v. infusion of PGE2 also induced a dose related inhibition of baclofen-stimulated acid secretion, but 10 fold higher doses were required. I.ci. or i.v. injection of indomethacin in doses ranging from 50 to 500 micrograms/rat, produced a similar dose dependent inhibition of the PGE2 generation in both the gastric mucosa and brain cortex measured 1 h post injection. I.ci. injection of indomethacin (500 micrograms) increased within 10 min acid secretion with a peak response at 20-30 min; 60-120 min post injection, when prostaglandin synthesis was inhibited by 90%, basal and baclofen-stimulated acid output were not altered. These results further establish that PGE2 acts in the brain to inhibit vagally stimulated gastric acid secretion in rats, and do not support a tonic inhibitory influence of endogenous brain PGE2 in the regulation of gastric acid secretion. In addition, these data showed that indomethacin injected i.ci. at 500 micrograms does not induce a selective inhibition of prostaglandin synthesis in the brain.

Gastric cytoprotection by intracisternal interleukin-1 beta in the rat

The effects of intracisternal (ic) injection of recombinant interleukin-1 beta (IL-1) on absolute ethanol-induced gastric necrotic lesions were studied in conscious rats. IL-1 given ic inhibited ethanol-induced gastric lesions. The cytoprotective effect was dose dependent (ED175 ng/rat), long lasting with a maximal action when given 1-3 h prior to ethanol, blocked by ic injection of a IL-1 receptor antagonist protein (IRAP), and by intraperitoneal injection of indomethacin. IL-1, injected ic, was detected in the peripheral blood. However, IL-1 serum levels were lower after IL-1 injection ic than after ip at a dose giving equal gastric protection. These data show that ic IL-1 induces long lasting gastric protection mediated by interaction with IL-1 receptors and prostaglandin pathways at central and/or peripheral sites that remain to be localized.

Increased gastric PGE2 biosynthesis in cirrhotic patients with gastric vascular ectasia

Plasma levels of glucagon, secretin, norepinephrine, arginine-vasopressin, and prostaglandin biosynthesis in the gastric mucosa were determined in cirrhotic patients with gastric vascular ectasia associated with hypoacidity, in cirrhotics without this lesion, and in healthy controls. Plasma concentrations of glucagon, secretin, and norepinephrine were similar in cirrhotics with gastric vascular ectasia and cirrhotics without this lesion, these concentrations being significantly higher (p less than 0.05) than in healthy controls. However, there was no significant difference between plasma levels of arginine-vasopressin in patients with cirrhosis (with or without gastric vascular ectasia) and those in healthy controls. The biosynthesis of prostaglandin E2 in the antrum of the gastric mucosa was significantly higher in cirrhotics with gastric vascular ectasia than in cirrhotics without this lesion (p less than 0.05) and healthy controls (p less than 0.005). Prostaglandin E2 in the corpus was significantly higher (p less than 0.05) in cirrhotics with gastric vascular ectasia than in healthy controls. The biosynthesis of 6-keto PGF1 alpha (a stable metabolite of prostacyclin) and PGF2 alpha in the corpus and antrum of gastric mucosa was not significantly different in cirrhotics with gastric vascular ectasia, cirrhotics without this lesion and healthy controls. Since prostaglandin E2 has a vasodilator and acid-inhibitory effect, we speculate that high content of this prostanoid in the gastric mucosa may play a role in the pathogenesis of ectatic capillaries and acid inhibition present in some cirrhotic patients.

Gastric vascular ectasias in cirrhosis: association with hypoacidity not related to gastric atrophy

To investigate whether hypergastrinemia and low serum levels of pepsinogen I are associated with gastric hypoacidity in cirrhosis with capillary ectasia of gastric mucosa and whether this alteration is secondary to the presence of atrophic gastritis, two groups of patients were studied: 1) 12 cirrhotic patients with diffuse gastric red spots at the endoscopic examination, and 2) 12 cirrhotic patients with endoscopically normal mucosa. Vascular ectasia of the gastric mucosa was histologically confirmed in all patients with gastric red spots. The study of base-line and stimulated acid gastric secretion showed that 9 of 12 (75%) cirrhotics with gastric vascular ectasia had achlorhydria and that 8 of these 9 patients had high base-line gastrin serum levels (greater than 130 pg/ml) and low base-line pepsinogen I serum levels (less than 20 ng/ml). Base-line gastrin and pepsinogen I serum levels were significantly greater and lower, respectively, in patients with gastric vascular ectasias than in cirrhotics without these lesions. None of the patients of either group had complete atrophy in the corpus of the stomach, and only 4 of the 9 cirrhotics with gastric vascular ectasia and achlorhydria had moderate atrophy. These results show that achlorhydria is frequently associated with hypergastrinemia and low pepsinogen I serum levels in patients with cirrhosis and gastric vascular ectasias and suggest that this disturbance is not secondary to a morphologic abnormality of the gastric mucosa.

Comparison of snare and large forceps biopsies in the histologic diagnosis of gastric vascular ectasia in cirrhosis

To compare snare and large forceps biopsies in the histologic diagnosis of gastric vascular ectasia (GVE) in cirrhosis, two groups of patients were studied: (a) 8 cirrhotic patients in whom endoscopy disclosed multiple gastric red spots (GRS), and (b) 5 cirrhotic patients with no GRS. Histologic examination of snare specimens identified dilated capillaries in the mucosa of the stomach in 75% of the cirrhotic patients with GRS, while large forceps specimens enabled the diagnosis of GVE only in 20% of the cases (p less than 0.05). Morphometric analysis of snare specimens demonstrated a significantly greater mean mucosal capillary cross-sectional area in cirrhotic patients with GRS than in cirrhotic patients without these lesions (p less than 0.05), while no differences in this parameter was observed in large forceps specimens. These findings indicate that gastric mucosal specimens obtained with large forceps are not useful for establishing the histologic diagnosis of GVE in cirrhotic patients with GRS.

Somatostatin compared with cimetidine in the treatment of bleeding peptic ulcer without visible vessel

In a randomized double-blind trial 100 patients with severe bleeding peptic ulcers were treated with an intravenous (i.v.) infusion of cimetidine or somatostatin. Only those patients in whom endoscopy performed within 6 h of admission showed non-arterial bleeding or signs of recent haemorrhage without a visible vessel entered the trial. The two treatment groups were well matched for age, sex, presence of underlying disease, prior ingestion of ulcerogenic drugs, tobacco habits, type of bleeding, haematocrit at admission, presence of hypovolaemic shock, source of bleeding and endoscopic findings. Four patients in each group were excluded after randomization. Further haemorrhage occurred in eight (17.3%) patients in the somatostatin group and in 10 (21.7%) in the cimetidine group, but the difference was not statistically significant. The number of surgical procedures, blood transfusion requirement, duration of hospitalization and mortality rates were similar in the two treatment groups. These results suggest that somatostatin does not improve the results obtained with cimetidine in patients with bleeding peptic ulcer, in whom the endoscopy discloses non-arterial bleeding or signs of recent haemorrhage without a visible vessel.

Conservative management of bleeding duodenal ulcer without a visible vessel: prospective randomized trial

Between January 1983 and December 1985, 305 patients were admitted to our hospital because of bleeding duodenal ulcer. A subgroup of 69 patients aged 50 or above in whom emergency endoscopy showed non-arterial bleeding or signs of recent haemorrhage without a visible vessel entered a prospective therapeutic trial. The patients were randomized to receive either (1) early surgery, implying immediate operation, or (2) expectant management, with surgery reserved only for patients with further haemorrhage. The two groups were homogeneous with respect to age, sex, prior ingestion of ulcerogenic drugs, mode of bleeding, admission haematocrit, number with hypovolaemic shock and number with active bleeding on initial endoscopy. Overall mortality was 8.6 per cent. Mortality in patients submitted to early surgery was five times higher than that in those allocated to expectant therapy (14.7 per cent versus 2.9 per cent; risk ratio 5.07). The results suggest that expectant management is advisable in patients with bleeding duodenal ulcer not bleeding massively and in whom endoscopy does not disclose spurting arterial bleeding or a visible vessel.