A Comparative Study of Acute Alcoholic Hepatitis vs. Non-Alcoholic Hepatitis Patients from a Cohort with Chronic Alcohol Dependence

The rate of alcoholic hepatitis (AH) has risen in recent years. AH can cause as much as 40-50% mortality in severe cases. Successful abstinence has been the only therapy associated with long-term survival in patients with AH. Thus, it is crucial to be able to identify at-risk individuals in order to implement preventative measures. From the patient database, adult patients (age 18 and above) with AH were identified using the ICD-10 classification from November 2017 to October 2019. Liver biopsies are not routinely performed at our institution. Therefore, patients were diagnosed with AH based on clinical parameters and were divided into "probable" and "possible" AH. Logistic regression analysis was performed to determine risk factors associated with AH. A sub-analysis was performed to determine variables associated with mortality in AH patients. Among the 192 patients with alcohol dependence, there were 100 patients with AH and 92 patients without AH. The mean age was 49.3 years in the AH cohort, compared to 54.5 years in the non-AH cohort. Binge drinking (OR 2.698; 95% CI 1.079, 6.745; p = 0.03), heavy drinking (OR 3.169; 95% CI 1.348, 7.452; p = 0.01), and the presence of cirrhosis (OR 3.392; 95% CI 1.306, 8.811; p = 0.01) were identified as characteristics more commonly found in the AH cohort. Further, a higher inpatient mortality was seen in those with a probable AH diagnosis (OR 6.79; 95% CI 1.38, 44.9; p = 0.03) and hypertension (OR 6.51; 95% CI 9.49, 35.7; p = 0.02). A higher incidence of mortality was also noted among the non-Caucasian race (OR 2.72; 95% CI 4.92; 22.3; p = 0.29). A higher mortality rate despite a lower incidence of alcohol use among non-Caucasian patients may indicate healthcare disparities.

A Rare Case of Methotrexate-Induced Gastric Ulcer

Methotrexate is commonly used to treat autoimmune conditions and malignancy. Peptic ulcer disease is a sparsely documented side effect of methotrexate. A 70-year-old female patient with rheumatoid arthritis on methotrexate presented with generalized fatigue and was found to be anemic. Endoscopy revealed gastric ulcers, the etiology of which was attributed to methotrexate use after careful exclusion of other possible causes. Cessation of methotrexate has been reported in the literature as vital to the healing of ulcers. Proton pump inhibitors or histamine 2 receptor (H2R) blockers may also be used as treatment; however, methotrexate should be discontinued before initiation of proton pump inhibitors, which can hinder the metabolism of methotrexate and can, in turn, lead to a worsening of the peptic ulcer disease.

A Systematic Review of the Efficacy and Safety of Fecal Microbiota Transplantation in the Treatment of Hepatic Encephalopathy and Clostridioides difficile Infection in Patients With Cirrhosis

The microbiome of the human gut and liver coexists by influencing the health and disease state of each system. Fecal microbiota transplantation (FMT) has recently emerged as a potential treatment for conditions associated with cirrhosis, such as hepatic encephalopathy and recurrent/refractory Clostridioides difficile infection (rCDI). We have conducted a systematic review of the safety and efficacy of FMT in treating hepatic encephalopathy and rCDI. A literature search was performed using variations of the keywords "fecal microbiota transplant" and "cirrhosis" on PubMed/MEDLINE from inception to October 3, 2021. The resulting 116 articles were independently reviewed by two authors. Eight qualifying studies were included in the systematic review. A total of 127 cirrhotic patients received FMT. Hepatic encephalopathy was evaluated by cognitive tests, such as the Psychometric Hepatic Encephalopathy Score (PHES) and EncephalApp Stroop test. Not only was there an improvement in the cognitive performance in the FMT cohort, but the improvement was also maintained throughout long-term follow-up. In the treatment of rCDI, the FMT success rate is similar between cirrhotic patients and the general population, although more than one dose may be needed in the former. The rate of serious adverse events and adverse events in the cirrhotic cohort was slightly higher than that in the general population but was low overall. We found evidence that supports the therapeutic potential and safety profile of FMT to treat hepatic encephalopathy and rCDI in cirrhotic patients. Further research will be beneficial to better understand the role of FMT in cirrhosis.

Intraluminal Endovascular Coil Migration: A Rare Complication Post-Embolization of the Gastroduodenal Artery for a Previously Bleeding Duodenal Ulcer

Transarterial angiographic embolization is a highly effective, safe treatment for non-variceal upper gastrointestinal bleeding refractory to endoscopic intervention. However, intraluminal coil migration is a possible complication. Coil migration, while usually a self-limiting process, can lead to significant rebleeding. In our case, a patient presented with a life-threatening duodenal ulcer hemorrhage, likely precipitated by intraluminal endovascular coil migration after a recent gastro-duodenal artery embolization. He was successfully managed without endoscopic coil removal and had no additional gastrointestinal bleeding. It is important for endoscopists to be aware of this complication and weigh the risks and benefits of coil removal.

Utility of inflammatory markers to predict adverse outcome in acute pancreatitis: A retrospective study in a single academic center

BACKGROUND/AIM

Acute pancreatitis (AP) is a commonly encountered emergency where early identification of complicated cases is important. Inflammatory markers like lymphocyte to monocyte ratio (LMR) and neutrophil to lymphocyte ratio (NLR) are simple and readily available markers. In this study, we evaluated the utility of these markers in the early identification of patients with complicated AP.

PATIENTS AND METHODS

All patients with a diagnosis of AP admitted to the University Medical Center in Las Vegas/Nevada between August 2015 and September 2018 were identified using ICD-10 codes. Medical records were reviewed retrospectively. Epidemiological measures and their associated confidence intervals were calculated using MedCalc (v. 18).

RESULTS

The LMR showed a significant difference between groups, with the non-complicated cases consistently higher than the complicated cases but without significant temporal differences. The NLR showed a significant difference with a significant temporal relation. Using the bound of the 95% confidence interval separating the two groups, LMR <2 was found to be associated with a complicated case and NLR >10.5 was suggestive of a complicated case. High specificity (85-92%) with low sensitivity (23-69%) was noted; hence, these cut points were very good at discerning non-complicated cases.

CONCLUSION

Our data show persistently low LMR that is associated with severe AP and a value of <2.0 can be used clinically to predict severe AP on admission. It also shows that elevated NLR is associated with complicated AP and prolonged hospital stay with a value >10.5 that can be used to predict severe complicated AP and to monitor response to treatment over time.

Proton pump inhibitor in upper gastrointestinal fecal microbiota transplant: A systematic review and analysis

BACKGROUND AND AIMS

Fecal microbiota transplantation (FMT) is used in recurrent Clostridioides difficile infections. However, protocols are facility dependent, and one variable is whether pre-procedural proton pump inhibitors (PPIs) are given. In theory, PPIs reduce acidity and protect the transplanted microbiome for the most potent dose. We conducted a systematic review to study the effect of PPIs on FMT delivered by upper gastrointestinal (GI) routes.

METHODS

We searched Pubmed/Medline, Cochrane Library, Embase, Scopus, and Web of Science through December 16, 2018 using variations of keywords "fecal microbiota transplant" and "Clostridium difficile infection." Two authors independently reviewed 4210 results and found 11 qualifying studies with data on upper GI FMT, use of PPIs, and the rate of treatment failure at follow-up.

RESULTS

Of 233 included patients, treatment failure occurred in 20.6% of those with use of PPIs versus 22.6% in the group without (relative risk 0.91; confidence interval 0.56-1.50). Limitations include the lack of studies directly comparing outcomes based on use of PPIs and inability to control for possible confounders such as chronic PPI use, amount of stool transplanted, and pre-FMT antibiotics.

CONCLUSIONS

We did not find evidence supporting a clinically significant benefit from routine use of PPIs in FMT protocol. It is possible that the theoretical benefit from improved survival of transplanted microbiota is offset by negative effects on the microbiome. We suggest that routine use of PPIs in upper GI FMT be reconsidered. Further investigation is needed to optimize protocols for safety and efficacy.

EDGE in Roux-en-Y gastric bypass: How does it compare to laparoscopy-assisted and balloon enteroscopy ERCP: a systematic review and meta-analysis

Background and study aims  Endoscopic ultrasound-directed transgastric ERCP (EDGE) is a new endoscopic procedure to perform ERCP in Roux-en-y gastric bypass (RYGB) patients. The aim of this study was to conduct a systematic review and meta-analysis to evaluate technical success, clinical success and adverse effects of EDGE and compare it to laparoscopic ERCP (LA-ERCP) and balloon ERCP (BE-ERCP). Patients and methods  We conducted a comprehensive search of several databases and conference proceedings including PubMed, EMBASE, Google-Scholar, LILACS, SCOPUS, and Web of Science databases to identify studies reporting on EDGE, LA-ERCP, and BE-ERCP. The primary outcome was to evaluate technical and clinical success of all three procedures and the secondary analysis focused on calculating the pooled rate of all adverse events (AEs), along with the commonly reported AE subtypes. Results  Twenty-four studies on 1268 patients were included in our analysis with the majority of the population being males with mean age 53.72 years. Pooled rates of technical and clinical success with EDGE wer 95.5 % and 95.9 %, with LA-ERCP were 95.3 % and 92.9 % and were BE-ERCP were 71.4 % and 58.7 %, respectively. Pooled rates of all AEs with EDGE were 21.9 %, with LA-ERCP 17.4 % and with BE-ERCP 8.4 %. Stent migration was the most common AE with EDGE with 13.3 % followed by bleeding with 6.6 %. Conclusion  Our meta-analysis demonstrated that the technical and clinical success of EDGE procedure is better than BE-ERCP and comparable to that of LA-ERCP in RYGB patients. EDGE also has a similar safety profile as compared to LA-ERCP but has higher AE rate as compared to BE-ERCP.

EUS-guided biliary drainage: A systematic review and meta-analysis

ERCP is the current procedure of choice for patients with jaundice caused by biliary obstruction. EUS-guided biliary drainage (EUS-BD) has emerged as an alternative to ERCP in patients requiring biliary drainage. The aim of the study was to conduct a systematic review and meta-analysis to report the overall efficacy and safety of EUS-BD. We conducted a comprehensive search of several databases including PubMed, EMBASE, Web of Science, Google Scholar, and LILACS databases (earliest inception to June 2018) to identify studies that reported EUS-BD in patients. The primary outcome was to look at the technical and clinical success of the procedure. The secondary analysis focused on calculating the pooled rate of re-interventions and all adverse-events, along with the commonly reported adverse-event subtypes. Twenty-three studies reporting on 1437 patients were identified undergoing 1444 procedures. Majority of the patient population were male (53.86%), with an average age of 67.22 years. The pooled technical success rates and clinical success rates were 91.5% (95% confidence interval [CI]: 87.7-94.2, I^[2] = 76.5) and 87% (95% CI: 82.3-90.6, I^[2] = 72.4), respectively. The total adverse event rates were 17.9% (95% CI: 14.3-22.2, I^[2] = 69.1). Subgroup analysis of three major individual adverse events was bile leak: 4.1% (2.7-6.2, I^[2] = 46.7), stent migration: 3.9% (2.5-6.2, I^[2] = 43.5), and infection: 3.8% (2.8-5.1, I^[2] = 0) Substantial heterogeneity was noted in the analysis. EUS-BD has high technical and clinical success rate and hence a very effective procedure. Concerns about publication bias exist. Careful consideration should be given to the adverse events and weighing the risks and benefits of the alternative nonsurgical/surgical approaches.

Autoimmune hepatitis in patients with human immunodeficiency virus infection: A systematic review of the published literature

BACKGROUND

Liver disease in patients with HIV is common and typically has complex and multifactorial presentations that represent a major cause of morbidity and mortality. Autoimmune hepatitis (AIH) is rarely reported in patient with HIV and the disease course and clinical outcomes for treatment have not been well characterized. We are aiming to determine the patient characteristics, disease prevalence, and treatment outcomes from published articles of patients with HIV and AIH.

METHOD

A systematic search of PubMed, Web of Science, and Google Scholar through February 20, 2019 identified 15 studies that reported the outcomes of AIH in patients with HIV. Because of the small sample sizes and skewed distributions, resampling tests of mean differences using permutation distributions (MAXn = 10,000 permutations) were utilized; analyses were performed using R (v. 3.5.1). Categorical differences were calculated using Fisher exact test for odds ratio = 1 (equal odds), and Cramer V was calculated for effect size; analyses were completed in SPSS (v. 25).

RESULTS

By reviewing 15 studies reporting a total of 35 patients with AIH and HIV, male patients were found to have significantly higher aspartate transaminase and alanine transaminase levels at time of diagnosis. No other significant findings identified. The CD4 count and viral load did not show significant correlation with AIH diagnosis or its prognosis. All patients but one who presented with severe immune deficiency and responded to highly active anti-retroviral therapy received immunosuppressive treatment without side effects and achieved remission except 2 lost to follow-up and 3 expired.

CONCLUSION

Although rare, but AIH can develop in patients with HIV and physicians should consider it in the differential diagnosis for HIV patients presented with abnormal liver function tests, especially after excluding hepatitis C virus and drug-induced liver injury.Patients with immune deficiency disorders who present with AIH can be treated safely with steroid either as monotherapy or in combination with another immune suppressant therapy.

Endoscopic retrograde cholangiopancreatography in cirrhosis - a systematic review and meta-analysis focused on adverse events

AIM

To investigate indications and outcomes of endoscopic retrograde cholangiopancreatography (ERCP) in cirrhotics, especially adverse events. Patients with cirrhosis undergoing ERCP are believed to have increased risk. However, there is a paucity of literature describing the indications and outcomes of ERCP procedures in patients with cirrhosis, especially focusing on adverse events.

METHODS

We performed a systematic appraisal of major literature databases, including PubMed and EMBASE, with a manual search of literature from their inception until April 2017.

RESULTS

A total of 6,505 patients from 15 studies were analyzed (male ratio 59%, mean age 59 years), 11% with alcoholic and 89% with non-alcoholic cirrhosis, with 56.2% Child-Pugh class A, and 43.8% class B or C. Indications for ERCP included choledocholithiasis 60.9%, biliary strictures 26.2%, gallstone pancreatitis 21.1% and cholangitis 15.5%. Types of interventions included endoscopic sphincterotomy 52.7%, biliary stenting 16.7% and biliary dilation 4.6%. Individual adverse events included hemorrhage in 4.58% (95%CI: 2.77-6.75%, I 2 = 85.9%), post-ERCP pancreatitis (PEP) in 3.68% (95%CI: 1.83-6.00%, I 2 = 89.5%), cholangitis in 1.93% (95%CI: 0.63-3.71%, I 2 = 87.1%) and perforation in 0.00% (95%CI: 0.00-0.23%, I 2 = 37.8%). Six studies were used for comparison of ERCP-related complications in cirrhosis vs non-cirrhosis, which showed higher overall rates of complications in cirrhosis patients with pooled OR of 1.63 (95%CI: 1.27-2.09, I 2 = 65%): higher rates of hemorrhage with OR of 2.05 (95%CI: 1.62-2.58, I 2 = 2.1%) and PEP with OR of 1.33 (95%CI: 1.04-1.70, I 2=65%), but similar cholangitis rates with OR of 1.23 (95%CI: 0.67-2.26, I 2 = 44.3%).

CONCLUSION

There is an overall higher rate of adverse events related to ERCP in patients with cirrhosis, especially hemorrhage and PEP. A thorough risk/benefit assessment should be performed prior to undertaking ERCP in patients with cirrhosis.

Comparison of outcomes for supine vs. prone position ERCP: a systematic review and meta-analysis

Background  While endoscopic retrograde cholangiopancreatography (ERCP) is usually performed in the prone position, some studies have advocated for ERCP in the supine position. Studies comparing the technical success and safety outcomes have shown variable results. We performed a systematic review and meta-analysis of studies reporting the comparison between the two positions for ERCP outcomes. Methods  We conducted a search of electronic databases and conference proceedings including PubMed, EMBASE, and Web of Science databases (from inception through October 2016) to identify studies that reported the comparison of technical success and safety outcomes between supine and prone ERCP. The primary outcome was to estimate the pooled rates of technical success. The secondary outcome was to estimate the risks of complications, such as cardiopulmonary and post-ERCP pancreatitis (PEP). Results  Six studies reporting on 309 supine and 1415 prone ERCPs were identified. The pooled technical success rates for completion of ERCP in supine and prone positions were 89.1 % (95 %CI = 80.9 - 94.0) and 95.6 % (95 %CI = 91.5 - 97.7), respectively. The pooled rates for complications (cardiopulmonary and PEP) in the supine position were 37.5 % (95 %CI = 19.1 - 60.3) and 3.5 % (95 %CI = 1.6 - 7.3), respectively. The pooled rates for complications (cardiopulmonary and PEP) in the prone position were 41.0 % (95 %CI = 20.9 - 64.8) and 3.9 % (95 %CI = 2.4 - 6.4), respectively. The mean time required for the procedure was 30 minutes and 29.8 minutes for supine and prone positions, respectively. Substantial heterogeneity was noted in the analysis. Conclusion  Prone ERCPs have a higher technical success rate with a slightly lower mean duration but a higher number of adverse events. The decision with regard to patient position should be made after evaluating the overall clinical scenario.

Laparotomy and intraoperative enteroscopy for obscure gastrointestinal bleeding before and after the era of video capsule endoscopy and deep enteroscopy: A tertiary center experience

BACKGROUND

To evaluate roles of intraoperative endoscopy (IOE) in management of severe obscure GI bleeding (OGIB) before vs. after introduction of video capsule endoscopy (VCE) and deep enteroscopy (DE).

METHODS

We retrospectively reviewed prospectively collected data of patients undergoing IOE for severe OGIB in a tertiary referral center.

RESULTS

52 patients had laparotomy/IOE for OGIB, 11 pre and 41 post VCE/DE eras. In the pre VCE/DE era, 36.4% (4/11) had preoperative presumptive diagnoses while in the post VCE/DE era presumptive diagnoses were made in 48.8% (20/41) (p = 0.18). Preoperative evaluation led to correct diagnoses in 18.2% (2/11) in the pre and 51.2% (21/41) in the post VCE/DE era (p = 0.09). Vascular lesions and ulcers were the most common diagnoses, but rebleeding was common. No rebleeding was found among patients with tumors, Meckel's diverticulum, and aortoenteric fistula.

CONCLUSIONS

Presumptive diagnoses in the post VCE/DE era were usually accurate. If VCE or DE are negative, the probability of negative IOE is high. Patients with tumors and Meckel's diverticulum were the best candidates for IOE.

Evidence for alterations in central noradrenergic signaling in irritable bowel syndrome

BACKGROUND/AIMS

Alterations in noradrenergic (NE) signaling have been implicated in the pathophysiology of irritable bowel syndrome (IBS), and adrenergic receptors are potential treatment targets.

METHODS

To characterize central NE signaling in IBS, 11 patients and 11 healthy controls (HCs) were studied 3 times during an auditory oddball vigilance task after double-blind ingestion of the α2-adrenoreceptor (α2AR) antagonist yohimbine (YOH), the α2AR agonist clonidine (CLO), or placebo (PLA). Regional cerebral glucose metabolism was measured with [¹⁸F] fluorodeoxyglucose (FDG) positron emission tomography (PET). Measures of anxiety, early-life trauma, plasma NE and blood pressure were acquired.

RESULTS

Patients had higher plasma NE levels than HCs before and after ingestion of all drugs (all p<0.05). YOH increased plasma NE and more anxiety in patients than in HCs. After YOH, NE levels directly correlated with drug-induced increases in anxiety in IBS patients (r=0.61), but not in HCs. IBS patients showed less YOH-mediated reduction of activity in a central arousal circuit, consistent with fewer functional presynaptic α2AR. In HCs, but not in patients, activation of amygdala and subgenual anterior cingulate cortex (sgACC) was inversely correlated with activation of anterior mid cingulate cortex (aMCC), and state anxiety covaried directly with activity in limbic and right frontotemporal cortices, but indirectly with activity in the left frontotemporal cortex. YOH-mediated reduction of activity in brainstem and amygdala inversely correlated with early life trauma.

CONCLUSIONS

IBS patients showed evidence for increased noradrenergic activity consistent with downregulation of presynaptic inhibitory α2ARs. Activity within central arousal circuits was biased toward greater excitability and reduced corticolimbic inhibition in IBS. Early life trauma may be one mediator of these abnormalities.

CCK-8 and CCK-58 differ in their effects on nocturnal solid meal pattern in undisturbed rats

Various molecular forms of CCK reduce food intake in rats. Although CCK-8 is the most studied form, we reported that CCK-58 is the only detectable endocrine peptide form in rats. We investigated the dark-phase rat chow intake pattern following injection of CCK-8 and CCK-58. Ad libitum-fed male Sprague-Dawley rats were intraperitoneally injected with CCK-8, CCK-58 (0.6, 1.8, and 5.2 nmol/kg), or vehicle. Food intake pattern was assessed during the dark phase using an automated weighing system that allowed continuous undisturbed monitoring of physiological eating behavior. Both CCK-8 and CCK-58 dose dependently reduced 1-h, dark-phase food intake, with an equimolar dose of 1.8 nmol being similarly effective (-49% and -44%). CCK-58 increased the latency to the first meal, whereas CCK-8 did not. The intermeal interval was reduced after CCK-8 (1.8 nmol/kg, -41%) but not after CCK-58. At this dose, CCK-8 increased the satiety ratio by 80% and CCK-58 by 160%, respectively, compared with vehicle. When behavior was assessed manually, CCK-8 reduced locomotor activity (-31%), whereas grooming behavior was increased (+59%). CCK-58 affected neither grooming nor locomotor activity. In conclusion, reduction of food intake by CCK-8 and CCK-58 is achieved by differential modulation of food intake microstructure and behavior. These data highlight the importance of studying the molecular forms of peptides that exist in vivo in tissue and circulation of the animal being studied.

The water exchange method for colonoscopy-effect of coaching

The growing popularity of water immersion is supported by its long history as an adjunct to air insufflation; after facilitating colonoscope passage, the infused water is conveniently removed during withdrawal. Water exchange, a modification of water immersion to minimize discomfort in scheduled unsedated patients in the U.S. is new. Even though it may be superior in reducing pain and increasing adenoma detection, the paradigm shift to complete exclusion of air during insertion necessitates removal of infused water containing residual feces, a step often perceived as laborious and time-consuming. The nuances are the efficient steps to remove infused water predominantly during insertion to maintain minimal distension and deliver salvage cleansing. Mastery of the novel maneuvers with practice returns insertion time towards baseline. In this observational study the impact of direct verbal coaching on the primary outcome of intention-to-treat cecal intubation was assessed. The results showed that 14 of 19 (74%) experienced colonoscopists achieved 100% intention-to-treat cecal intubation. Initiation of the examination with water exchange did not preclude completion when conversion to the more familiar air insufflation method was deemed necessary to achieve cecal intubation (total 98%). The overall intention-to-treat cecal intubation rate was 88%, 90% in male and 87% in female. Only 2.7% of bowel preparation was rated as poor during withdrawal. The mean volume of water infused and cecal intubation time was 1558 ml and 18 min, respectively. Direct coaching appears to facilitate understanding of the nuances of the water exchange method. Studies of individual learning curves are necessary.

Ischemic colitis as a cause of severe hematochezia: risk factors and outcomes compared with other colon diagnoses

BACKGROUND

Risk factors and outcomes of severe hematochezia from ischemic colitis compared with other colonic diagnoses have not been well studied.

OBJECTIVE

Our purposes were (1) to compare demographics and outcomes of patients hospitalized with severe hematochezia from ischemic colitis compared with other colonic diagnoses, (2) to compare inpatient and outpatient start of bleeding from ischemic colitis, and (3) to describe potential risk factors.

DESIGN

Prospective cohort study.

SETTING

Tertiary referral academic centers.

PATIENTS

Patients referred for gastroenterology consultation for severe hematochezia.

INTERVENTIONS

Colonoscopic therapy was provided as indicated.

MAIN OUTCOME MEASUREMENTS

Rebleeding, surgery, and length of hospital stay after colonoscopy.

RESULTS

Of 550 patients in the past 12 years with severe hematochezia from colonic sources, the cause in 65 patients (11.8%) was ischemia. Ischemic colitis was found more often in females, in patients taking anticoagulant agents, in patients with severe lung disease, those with higher creatinine levels, those with higher glucose levels, and those with more fresh frozen plasma transfusions. Five patients with focal lesions had colonoscopic hemostasis. Major 30-day outcomes of ischemic colitis patients were significantly worse than patients with other colonic diagnoses. Patients with inpatient (vs outpatient) ischemic colitis had significantly more and more severe comorbidities at baseline and significantly higher rates of rebleeding, surgery, and more days spent in hospital and in the intensive care unit.

LIMITATIONS

Two-center study.

CONCLUSIONS

Major 30-day outcomes in ischemic colitis patients were significantly worse than in patients with other colonic diagnoses. Comparing outpatient and inpatient start of ischemic colitis, inpatients had significantly worse outcomes.

Comparison of CRF-immunoreactive neurons distribution in mouse and rat brains and selective induction of Fos in rat hypothalamic CRF neurons by abdominal surgery

Mice and rats are widely used in stress-related behavioral studies while little is known about the distribution of the stress hormone, corticotropin-releasing factor (CRF) in the mouse brain. We developed and characterized a novel rat/mouse CRF polyclonal antibody (CURE ab 200101) that was used to detect and compare the brain distributions of CRF immunoreactivity in naïve and colchicine-treated rats and mice. We also assessed whether the visceral stressor of abdominal surgery activated brain CRF neurons using double labeling of Fos/CRF in naïve rats. CRF-ir neurons were visualized in the cortex, bed nucleus of the stria terminalis, central amygdala, hypothalamic paraventricular nucleus (PVN), Barrington's nucleus and dorsolateral tegmental area in naïve rats. CRF-immunoreactive (ir) neurons in the mouse brain were detected only after colchicine. The pattern shows fundamental similarity compared to the colchicine-treated rat brain, however, there were differences with a lesser distribution in both areas and density except in the lateral septum and external subnucleus of the lateral parabrachial nucleus which contained more CRF-ir neurons in mice, and CRF-ir neurons in the dorsal motor nucleus of the vagus were found only in mice. Abdominal surgery in naïve rats induced Fos-ir in 30% of total CRF-ir neurons in the PVN compared with control (anesthesia alone) while Fos was not co-localized with CRF in other brain nuclei. These data indicate that CRF-ir distribution in the brain displays similarity as well as distinct features in mice compared to rats that may underlie some differential stress responses. Abdominal surgery activates CRF-ir neurons selectively in the PVN of rats without colchicine treatment.

Guanylate cyclase C-mediated antinociceptive effects of linaclotide in rodent models of visceral pain

BACKGROUND Linaclotide is a novel, orally administered investigational drug currently in clinical development for the treatment of constipation-predominant irritable bowel syndrome (IBS-C) and chronic idiopathic constipation. Visceral hyperalgesia is a major pathophysiological mechanism in IBS-C. Therefore, we investigated the anti-nociceptive properties of linaclotide in rodent models of inflammatory and non-inflammatory visceral pain and determined whether these pharmacological effects are linked to the activation of guanylate cyclase C (GC-C). METHODS Orally administered linaclotide was evaluated in non-inflammatory acute partial restraint stress (PRS) and acute water avoidance stress (WAS) models in Wistar rats, and in a trinitrobenzene sulfonic acid (TNBS)-induced inflammatory model in Wistar rats and GC-C null mice. KEY RESULTS In TNBS-induced colonic allodynia, linaclotide significantly decreased the number of abdominal contractions in response to colorectal distension without affecting the colonic wall elasticity change in response to distending pressures after TNBS. However, linaclotide had no effect on visceral sensitivity under basal conditions. In addition, linaclotide significantly decreased colonic hypersensitivity in the PRS and WAS models. In wild type (wt) and GC-C null mice, the instillation of TNBS induced similar hyperalgesia and allodynia. However, in post-inflammatory conditions linaclotide significantly reduced hypersensitivity only in wt mice, but not in GC-C null mice. CONCLUSIONS & INFERENCES These findings indicate that linaclotide has potent anti-nociceptive effects in several mechanistically different rodent models of visceral hypersensitivity and that these pharmacological properties of linaclotide are exerted through the activation of the GC-C receptor. Therefore, linaclotide may be capable of decreasing abdominal pain in patients suffering from IBS-C.

Childhood trauma is associated with hypothalamic-pituitary-adrenal axis responsiveness in irritable bowel syndrome

BACKGROUND & AIMS

A history of early adverse life events (EALs) is associated with a poorer outcome and higher levels of distress in adult patients with functional gastrointestinal disorders. An EAL is thought to predispose individuals to develop a range of chronic illnesses by inducing persistent changes in the central stress response systems, including the hypothalamic-pituitary-adrenal (HPA) axis. We sought to determine if EALs affect the HPA axis response to a visceral stressor in irritable bowel syndrome (IBS) patients and healthy controls, and to determine if this is affected by sex or related to symptoms or quality of life.

METHODS

Forty-four IBS patients (25 women, 19 men) and 39 healthy controls (21 women, 18 men) were assessed for gastrointestinal and psychological symptoms and EALs by validated questionnaires and interview. All subjects underwent a visceral stressor (sigmoidoscopy). Salivary cortisol was collected at baseline and serially for 1 hour poststressor.

RESULTS

Twenty-one IBS patients and 18 controls had EALs. In subjects with and without IBS, an EAL was associated with higher mean (+/-SD) cortisol levels (0.32 +/- 0.2 vs 0.20 +/- 0.1 microg/dL; P = .003) and higher area under the curve (28.1 +/- 17 vs 18.6 +/- 13 microg x min/dL; P = .005) after the stressor compared with subjects without EALs. In IBS, a faster resolution of cortisol to basal values corresponded to lower symptom severity (r = -0.36, P < .05) and better disease-specific quality of life (r = 0.33, P < .05).

CONCLUSIONS

HPA axis hyperresponsiveness to a visceral stressor is related more to a history of EALs than to the presence of IBS. However, HPA axis reactivity has a moderating effect on IBS symptoms.

Comparative efficacy of rabeprazole and pantoprazole in the control of nocturnal Acid output and intragastric acidity

BACKGROUND/AIMS

Nocturnal reflux is a largely undiagnosed and unmanaged condition predisposing to multiple esophageal complications. We evaluated the effects of rabeprazole and pantoprazole on nocturnal intragastric pH and gastric acid output during Day 1 of therapy following the consumption of standard meals.

METHODS

The study had a double-blinded, randomized, two-way crossover design, and involved 15 patients with a history of mild reflux. Following an overnight fast, patients were given either rabeprazole (20 mg) or pantoprazole (40 mg) prior to the first of three standard Western meals. They then underwent overnight continuous intragastric pH monitoring and gastric acid output measurement. The drug effect was analyzed using a two-treatment, two-period crossover mixed model.

RESULTS

The percentage of time during which the mean intragastric pH was greater than 4.0 and gastric acid output was less than 2.0 was higher for oral rabeprazole (p<0.05). The inhibition of acid output was greater for rabeprazole at almost all time points. Furthermore, the mean time-matched pH values differed significantly over the first 8.3 hours (p<0.05).

CONCLUSIONS

On day 1, oral rabeprazole inhibited acid output to a greater extent and for a longer period than pantoprazole, and the intragastric pH was significantly higher for rabeprazole than for pantoprazole over the first 8.3 hours.

The role of neurokinin 1 receptors in the maintenance of visceral hyperalgesia induced by repeated stress in rats

BACKGROUND & AIMS

The neurokinin 1 receptors (NK(1)Rs) and substance P (SP) have been implicated in the stress and/or pain pathways involved in chronic pain conditions. Here we examined the participation of NK(1)Rs in sustained visceral hyperalgesia observed in rats exposed to chronic psychological stress.

METHODS

Male Wistar rats were exposed to daily 1-hour water avoidance stress (WA) or sham WA for 10 consecutive days. We tested intraperitoneal or intrathecal injection of the NK(1)R antagonist SR140333 on the visceromotor reflex to colorectal distention in both groups at day 11. Real-time reverse-transcription polymerase chain reaction, Western blot, and immunohistochemistry were used to assess the expression of NK(1)Rs and/or SP in samples of colon, spinal cord, and dorsal root ganglia.

RESULTS

Both intraperitoneal and intrathecal SR140333 injection diminished the enhanced visceromotor reflex to colorectal distention at day 11 in stressed rats but did not affect the response in control animals. Real-time polymerase chain reaction and Western blotting demonstrated stress-induced up-regulation of spinal NK(1)Rs. Immunohistochemistry showed an increased number of NK(1)R-expressing neurons in the laminae I of the dorsal horn in stressed rats. The expression of NK(1)Rs was decreased in colon from stressed rats compared with control. The expression of SP gene precursor in dorsal root ganglia was unchanged in stressed rats compared with controls.

CONCLUSIONS

Stress-induced increased NK(1)R expression on spinal neurons and the inhibitory effect of intrathecal NK(1)R antagonist on visceral hyperalgesia support the key contribution of spinal NK(1)Rs in the molecular pathways involved in the maintenance of visceral hyperalgesia observed after chronic WA.

The neuropeptide tyrosine Y1R is expressed in interneurons and projection neurons in the dorsal horn and area X of the rat spinal cord

The localization of the neuropeptide tyrosine Y1 receptor was studied with immunohistochemistry in parasagittal and transverse, free-floating sections of the rat lumbar spinal cord. At least seven distinct Y1 receptor-positive populations could tentatively be recognized: Type 1) abundant small, fusiform Y1 receptor-positive neurons in laminae I-II, producing a profuse neuropil; Type 2) Y1 receptor-positive projection neurons in lamina I; Type 3) small Y1 receptor-positive neurons in lamina III, similar to Type 1 neurons, but less densely packed; Type 4) a number of large, multipolar Y1 receptor-positive neurons in the border area between laminae III-IV, with dendrites projecting toward laminae I-II; Type 5) a considerable number of large, multipolar Y1 receptor-positive neurons in laminae V-VI; Type 6) many large Y1 receptor-positive neurons around the central canal (area X); and Type 7) a small number of large Y1 receptor-positive neurons in the medial aspect of the ventral horns (lamina VIII). Many of the neurons present in laminae V-VI and area X produce craniocaudal processes extending for several hundred micrometers. Retrograde tracing using cholera toxin B subunit injected at the 9th thoracic spinal cord level shows that several Type 5 neurons in laminae V-VI, and at least a few Type 2 in lamina I and Type 6 in area X have projections extending to the lower segments of the thoracic spinal cord (and perhaps to supraspinal levels). The present results define distinct subpopulations of neuropeptide tyrosine-sensitive neurons, localized in superficial and deep layers of the dorsal, in the ventral horns and in area X. The lamina II neurons express somatostatin [The neuropeptide Y Y1 receptor is a somatic receptor on dorsal root ganglion neurons and a postsynaptic receptor on somatostatin dorsal horn neurons. Eur J Neurosci 11:2211-2225] and are presumably glutamatergic [Todd AJ, Hughes DI, Polgar E, Nagy GG, Mackie M, Ottersen OP, Maxwell DJ (2003) The expression of vesicular glutamate transporters VGLUT1 and VGLUT2 in neurochemically defined axonal populations in the rat spinal cord with emphasis on the dorsal horn. Eur J Neurosci 17:13-27], that is they are excitatory interneurons under a Y1 receptor-mediated inhibitory influence. The remaining Y1 receptor-positive spinal neurons need to be phenotyped, for example if the large Y1 receptor-positive laminae III-IV neurons (Type 5) are identical to the neurokinin (NK)1R-positive neurons previously shown to receive neuropeptide tyrosine positive dendritic contacts [Polgár E, Shehab SA, Watt C, Todd AJ (1999) GABAergic neurons that contain neuropeptide Y selectively target cells with the NK1 receptor in laminae III and IV of the rat spinal cord. J Neurosci 19:2637-2646]. If so, neuropeptide tyrosine could have an antinociceptive action not only via Y1 receptor-positive interneurons (Type 1) but also projection neurons. The present results show neuropeptide tyrosine-sensitive neuron populations virtually in all parts of the lumbar spinal cord, suggesting a role for neuropeptide tyrosine signaling in many spinal functions, including pain.

Corticotropin-releasing factor receptor 1 mediates acute and delayed stress-induced visceral hyperalgesia in maternally separated Long-Evans rats

In rodents, maternal pup interactions play an important role in programming the stress responsiveness of the adult organism. The aims of this study were 1) to determine the effect of different neonatal rearing conditions on acute and delayed stress-induced visceral sensitivity as well as on other measures of stress sensitivity of the adult animal; and 2) to determine the role of corticotropin-releasing factor receptor (CRF-R) subtype 1 (CRF(1)R) in mediating visceral hypersensitivity. Three groups of male Long-Evans rat pups were used: separation from their dam for 180 min daily from postnatal days 2-14 (MS180), daily separation (handling) for 15 min (H), or no handling. The visceromotor responses (VMR) to colorectal distension, stress-induced colonic motility, and anxiety-like behavior were assessed in the adult rats. The VMR was assessed at baseline, immediately after a 1-h water avoidance (WA) stress, and 24 h poststress. Astressin B, a nonselective CRF-R antagonist, or CP-154,526, a selective CRF(1)R antagonist, was administered before the stressor and/or before the 24-h measurement. MS rats developed acute and delayed stress-induced visceral hyperalgesia. In contrast, H rats showed hypoalgesia immediately after WA and no change in VMR on day 2. MS rats with visceral hyperalgesia also exhibited enhanced stress-induced colonic motility and increased anxiety-like behavior. In MS rats, both CRF-R antagonists abolished acute and delayed increases in VMR. Rearing conditions have a significant effect on adult stress responsiveness including immediate and delayed visceral pain responses to an acute stressor. Both acute and delayed stress-induced visceral hypersensitivity in MS rats are mediated by the CRF/CRF(1)R system.

Repeated exposure to water avoidance stress in rats: a new model for sustained visceral hyperalgesia

Chronic stress plays an important role in the development and exacerbation of symptoms in functional gastrointestinal disorders. To better understand the mechanisms underlying this relationship, we aimed to characterize changes in visceral and somatic nociception, colonic motility, anxiety-related behavior, and mucosal immune activation in rats exposed to 10 days of chronic psychological stress. Male Wistar rats were submitted daily to either 1-h water avoidance (WA) stress or sham WA for 10 consecutive days. The visceromotor response to colorectal distension, thermal somatic nociception, and behavioral responses to an open field test were measured at baseline and after chronic WA. Fecal pellets were counted after each WA stress or sham WA session as a measure of stress-induced colonic motility. Colonic samples were collected from both groups and evaluated for structural changes and neutrophil infiltration, mast cell number by immunohistochemistry, and cytokine expression by quantitative RT-PCR. Rats exposed to chronic WA (but not sham stress) developed persistent visceral hyperalgesia, whereas only transient changes in somatic nociception were observed. Chronically stressed rats also exhibited anxiety-like behaviors, enhanced fecal pellet excretion, and small but significant increases in the mast cell numbers and the expression of IL-1beta and IFN-gamma. Visceral hyperalgesia following chronic stress persisted for at least a month. Chronic psychological stress in rats results in a robust and long-lasting alteration of visceral, but not somatic nociception. Visceral hyperalgesia is associated with other behavioral manifestations of stress sensitization but was only associated with minor colonic immune activation arguing against a primary role of mucosal immune activation in the maintenance of this phenomenon.

Delayed stress-induced colonic hypersensitivity in male Wistar rats: role of neurokinin-1 and corticotropin-releasing factor-1 receptors

The mechanism(s) underlying stress-induced colonic hypersensitivity (SICH) are incompletely understood. Our aims were to assess the acute and delayed (24 h) effect of water avoidance (WA) stress on visceral nociception in awake male Wistar rats and to evaluate the role of two stress-related modulation systems: the substance P/neurokinin-1 receptor (SP/NK(1)R) and the corticotropin-releasing factor (CRF)/CRF(1) receptor (CRF/CRF(1)R) systems, as well as the possible involvement of the sympathetic nervous system. Visceral pain responses were measured as the visceromotor response to colorectal distension (CRD) at baseline, immediately after WA and again 24 h later. The NK(1)R antagonists RP-67580 and SR-140333 and the CRF(1)R antagonist CP-154526 were injected 15 min before WA or 1 h before the CRD on day 2. Chemical sympathectomy was performed by repeated injection of 6-hydroxydopamine. WA stress resulted in a significant increase in the visceromotor response on day 2, but no change immediately after WA. Injection of CP-154526 abolished delayed SICH when applied either before WA stress or before the CRD on day 2. Both NK(1)R antagonists only decreased SICH when injected before the CRD on day 2. Chemical sympathectomy did not affect delayed SICH. Our results indicate that in male Wistar rats, both NK(1)R and CRF(1)R activation, but not sympathetic nervous system activation, play a role in the development of SICH.

Anti-hyperalgesic effect of octreotide in patients with irritable bowel syndrome

BACKGROUND

Octreotide has been found to be beneficial in the treatment of chronic pain, although the mechanisms underlying its therapeutic effect are incompletely understood.

AIMS

To assess the effect of octreotide on perceptual responses to rectal distension in irritable bowel syndrome patients and healthy controls at baseline and following the experimental induction of rectal hyperalgesia.

METHODS

In study 1, rectal perception thresholds for discomfort were determined in seven irritable bowel syndrome patients and eight healthy controls on three separate days using a computer-controlled barostat. Subjects received saline, low-dose and high-dose octreotide in a random double-blind fashion. In study 2, perceptual responses to rectal distension were obtained in nine irritable bowel syndrome patients and seven controls before and after repetitive high-pressure mechanical sigmoid stimulation.

RESULTS

Octreotide increased the discomfort thresholds in irritable bowel syndrome patients, but not in controls, without changing rectal compliance. Repetitive sigmoid stimulation resulted in decreased rectal discomfort thresholds in the patient group only. In irritable bowel syndrome patients, octreotide prevented the sensitizing effect of repetitive sigmoid stimulation on rectal discomfort thresholds.

CONCLUSIONS

Octreotide effectively increased discomfort thresholds in irritable bowel syndrome patients, but not in controls, at baseline and during experimentally induced rectal hyperalgesia. These findings suggest that octreotide exerts primarily an anti-hyperalgesic rather than analgesic effect on visceral perception.

Cephalic phase of acid secretion involves activation of medullary TRH receptor subtype 1 in rats

Mechanisms involved in the cephalic phase of gastric acid secretion were studied in awake fasted rats with chronic gastric fistula and exposed to the sight and smell of chow for 30 min. Acid secretion was monitored using constant intragastric perfusion and automatic titration. Sham feeding induced a peak acid response reaching 82 +/- 7 micromol/10 min within 20 min compared with the average 22 +/- 2 micromol/10 min in controls. The sham-feeding response was abolished by intracisternal pretreatment with the TRH(1)-receptor antisense oligodeoxynucleotides or subcutaneous injection of atropine, whereas TRH(1) mismatch oligodeoxynucleotides had no effect. Serum gastrin was not altered by the sham feeding and increased by refeeding. Gastrin antibody did not block the rise in acid during sham feeding, although the net acid response was reduced by 47% compared with the control group. Glycine-gastrin antibody, indomethacin and nitro-l-arginine methyl ester had no effect. Atropine and gastrin antibody decreased basal acid secretion by 98 and 75%, respectively, whereas all other pretreatments did not. These results indicate that the cholinergic-dependent acid response to sham feeding is mediated by brain medullary TRH(1) receptors in rats.

Activation of raphe pallidus neurons increases insulin through medullary thyrotropin-releasing hormone (TRH)-vagal pathways

INTRODUCTION

Pancreatic insulin secretion is regulated by the vagus nerve. Medullary thyrotropin-releasing hormone (TRH) containing projections from the raphe pallidus (Rpa) neurons innervate vagal preganglionic motor neurons in the dorsal vagal complex (DVC) and are involved in vagal regulation of gastric functions.

AIM

To investigate whether chemical stimulation of Rpa neurons influences circulating insulin levels through brain medullary TRH-vagal pathways.

METHODOLOGY

In fasted, pentobarbital-anesthetized rats, kainic acid (10 ng/50 nL) was microinjected into the Rpa, and serum insulin levels were measured. Gastric acid secretion was monitored as a control of vagally mediated visceral response.

RESULTS

Chemical stimulation of Rpa neuronal cell bodies significantly increased serum insulin levels. Values before and at 30, 60, and 90 minutes after the microinjection of kainic acid were 0.34 +/- 0.02, 0.54 +/- 0.06, 0.60 +/- 0.06, and 0.99 +/- 0.13 ng/mL, respectively. In the same rats, gastric acid secretion was stimulated (basal, 2.3 +/- 0.6, versus 26.1 +/- 8.6 micromol/15 min at 30 minutes). Microinjections outside of the Rpa had no effect. The Rpa stimulation-induced increase in serum insulin could be mimicked by DVC microinjection of TRH analog, completely prevented by bilateral cervical vagotomy, and significantly reduced by bilateral microinjection of TRH antibody into the DVC.

CONCLUSION

Chemical activation of Rpa neurons increases pancreatic insulin release through medullary TRH and vagal-mediated pathways.

Failure of a motilin receptor agonist (ABT-229) to relieve the symptoms of functional dyspepsia in patients with and without delayed gastric emptying: a randomized double-blind placebo-controlled trial

INTRODUCTION

Motilin-receptor agonists are prokinetics; whether they relieve the symptoms of functional dyspepsia is unknown. We aimed to test the efficacy of the motilin agonist ABT-229 in functional dyspepsia patients with and without delayed gastric emptying.

METHODS

Patients were randomized with postprandial symptoms and documented functional dyspepsia by endoscopy (n=589 in intention-to-treat analysis). Patients were assigned to either the delayed or normal gastric emptying strata, based on a validated 13C octanoic acid breath test. Patients were then further randomized within each strata, to receive one of four doses of ABT-229 (1.25, 2. 5, 5 or 10 mg b.d. before breakfast and dinner) or placebo for 4 weeks, following a 2-week baseline. The primary outcome was the assessment of change in symptom severity over the 2 weeks from baseline to final visit, based on a self-report questionnaire measuring severity on visual analogue scales.

RESULTS

Baseline characteristics across the treatment arms were very similar. No significant differences in the upper abdominal discomfort severity score (maximum 800 mm) were observed for any active treatment arm vs. placebo (mean change from baseline -139, -141, -145, -160 and -134 mm for placebo, 1.25, 2.5, 5, and 10 mg, respectively, at 4 weeks by intention-to-treat). More patients on placebo reported a good or excellent global response than patients on 1.25 or 5 mg of active therapy (both P < 0.05). The results were very similar in those with and without delayed gastric emptying. Helicobacter pylori status did not predict response. Excluding patients with any baseline heartburn (total remaining n=240), ABT-229 10 mg was inferior to placebo in relief of upper abdominal discomfort.

CONCLUSIONS

ABT-229 was of no value for relief of symptoms in functional dyspepsia, compared with placebo.

Peripheral PYY inhibits intracisternal TRH-induced gastric acid secretion by acting in the brain

The site of action of peripheral peptide YY (PYY)-induced inhibition of vagally stimulated gastric acid secretion was studied using immunoneutralization with PYY antibody in urethan-anesthetized rats. Gastric acid secretion (59+/-7 micromol/90 min) stimulated by intracisternal injection of the stable thyrotropin-releasing hormone (TRH) analog RX-77368 (14 pmol/rat) was dose-dependently inhibited by 52%, 69%, and 83% by intravenous infusion of 0.25, 0.5, and 1.0 nmol. kg(-1) x h(-1) PYY, respectively. PYY or PYY(3-36) (2.4 pmol/rat) injected intracisternally also inhibited the acid response to intracisternal RX-77368 by 73% and 80%, respectively. Intravenous pretreatment with PYY antibody (4.5 mg/rat), which shows a 35% cross-reaction with PYY(3-36) by RIA, completely prevented the inhibitory effect of intravenously infused PYY (1 nmol x kg(-1) x h(-1)). When injected intracisternally, the PYY antibody (280 microg/rat) reversed intracisternal PYY (2.4 pmol)- and intravenous PYY (1 nmol x kg(-1) x h(-1))-induced inhibition of acid response to intracisternal RX-77368 by 64% and 93.5%, respectively. These results provide supporting evidence that peripheral PYY inhibits central vagal stimulation of gastric acid secretion through an action in the brain.

Inhibition of pentagastrin-induced gastric acid secretion by intravenous pantoprazole: a dose-response study

OBJECTIVE

The purpose of this study was to compare the gastric acid inhibitory ability of increasing doses of intravenous (i.i.) pantoprazole with that of i.v. famotidine and placebo. Pentagastrin was infused continuously in healthy subjects as a model for patients with Zollinger-Ellison syndrome.

METHODS

Pentagastrin (1 microg/kg/h) was infused to stimulate maximum acid output in 39 subjects over a 25-h period. After 60 min of pentagastrin infusion, subjects received a single dose of i.v. pantoprazole (20, 40, 80, or 120 mg), i.v. famotidine (20 mg), or saline placebo. The variables measured were onset of response (time until acid output fell to < 10 mEq/h), duration of response (time acid output remained < 10 mEq/h), and cumulative acid output over 24 h.

RESULTS

All doses of i.v. pantoprazole produced a dose-dependent suppression of acid output to < 10 mEq/h. Single i.v. doses of pantoprazole, 80 and 120 mg, suppressed acid output by > 90% in all subjects for < or = 21 h and had an onset of action of < 1 h.

CONCLUSIONS

Intravenous pantoprazole has a rapid onset and a clear dose-related effect, with a significantly longer duration of action than that of i.v. famotidine.

Intracisternal TRH analog increases gastrin release and corpus histidine decarboxylase activity in rats

Thyrotropin-releasing hormone (TRH) acts in brain stem nuclei to induce vagally mediated stimulation of gastric secretion. The effects of intracisternal injection of the TRH analog RX-77368 on plasma gastrin levels and corpus histidine decarboxylase (HDC) activity were studied in 48-h fasted conscious rats. RX-77368 (25-100 ng) increased plasma gastrin levels by threefold at 30 min, which remained significantly higher than control at 2 and 4 h postinjection. Corpus HDC activity began to increase at 2 h and reached a peak at 4 h postinjection with a 21-fold maximum response observed at 50 ng. Morphological changes in the appearance of corpus HDC-immunoreactive cells correlated well with HDC activity. Pretreatment with gastrin monoclonal antibody completely prevented RX-77368 stimulatory effects on HDC activity. Atropine significantly attenuated gastrin increase at 30 min by 26%. These results indicated that in conscious fasted rats, TRH analog acts in the brain to increase corpus HDC activity in the enterochromaffin-like cells, which involves gastrin release stimulated by central TRH analog.

Prospective randomized comparative study of bipolar electrocoagulation versus heater probe for treatment of chronically bleeding internal hemorrhoids

BACKGROUND

Our purpose was to compare the efficacy, complications, failure rates, and crossovers of heater and bipolar probe treatments of chronically bleeding internal hemorrhoids.

METHODS

Eighty-one patients (31 female, 50 male) with mean age of 53 years had large (grade 2 to 3) internal hemorrhoids with bleeding for a mean of 12 years, had failed medical management, and were randomized in a prospective study of anoscopic treatments to heater versus bipolar probes. Failure was defined as a major complication or failure to reduce the size of all internal hemorrhoids with three or more treatments.

RESULTS

With similar background variables and no difference in treatment times, rectal bleeding and other symptoms were controlled in a shorter time with the heater probe than with the bipolar probe (77 versus 121 days). Five complications (fissures, bleeding, or rectal spasm) occurred with the bipolar probe, and two occurred with the heater probe. The heater probe caused more pain during treatments but had significantly fewer failures and crossovers.

CONCLUSIONS

For patients who had failed medical management of chronically bleeding internal hemorrhoids, the techniques and complications of heater and bipolar probes were similar, but pain was more common, failures and crossovers were less frequent, and the time to symptom relief was shorter with the heater probe than with the bipolar probe.

Intraislet regulation of pancreatic polypeptide secretion in the isolated perfused rat pancreas

The present study is to determine if intraislet insulin or somatostatin regulate pancreatic polypeptide (PP) secretion in the isolated perfused rat pancreas by infusing insulin or somatostatin antisera. Isolated rat pancreata were stimulated with either 16.7 mM glucose (G) alone, G with antisomatostatin antibody (G + SA), or G with antiinsulin antibody (G + IA). G inhibited PP secretion -22 +/- 9.5 pM below basal, a decrease of 9 +/- 6.3% (n = 6; p = NS), G + IA inhibited PP secretion -10 +/- 27.2 pM below basal, a decrease of 20 +/- 15% (n = 7, p = NS), and G + SA stimulated PP secretion 18 +/- 7.1 pM above basal, an increase of 26 +/- 5% (n = 6; p < 0.05). G stimulated insulin secretion 3,144 +/- 210 pM above basal (n = 6, p < 0.05), and G + SA stimulated insulin secretion 2,695 +/- 195 pM above basal (n = 7; p < 0.05 vs. baseline, p = NS vs. G alone). G stimulated C-peptide secretion 886 +/- 175 pM above basal (n = 6; p < 0.05), G + SA stimulated C-peptide secretion 847 +/- 102 pM above basal (n = 7; p < 0.05, p = NS vs. G alone), and G + IA stimulated C-peptide secretion 834 +/- 93 pM above basal (n = 7; p < 0.05, p = NS vs. G alone). These data demonstrate that infusion of SA results in significant stimulation of PP secretion during high-G infusion, whereas IA has no effect. Infusions of SA or IA at the doses used have no effect on G-stimulated insulin or C-peptide secretion. This suggests that intraislet somatostatin may be an inhibitory regulator of PP secretion in the isolated perfused rat pancreas.

Medullary thyrotropin-releasing hormone mediates vagal-dependent adaptive gastric protection induced by mild acid in rats

BACKGROUND & AIMS

Adaptive gastric protection is dependent on vagal pathways in rats. It is hypothesized that medullary thyrotropin-releasing hormone (TRH), known to regulate vagal function, is part of the brain mechanisms mediating adaptive gastric protection.

METHODS

Urethane-anesthetized rats were pretreated with either acute bilateral subdiaphragmatic vagotomy, sham operation, or intracisternal injection of purified control, TRH, or peptide YY antibody. Gastric lesions were assessed 75 minutes after orogastric administration of 1 mL of either vehicle or 0.35N HCl followed 15 minutes later by 0.6N or 1.0N HCl.

RESULTS

Injection of 0.6N and 1.0N HCl induced gastric lesions covering 23.1% +/- 2.7% and 37.8% +/- 3.3% of the corpus mucosa, respectively. Pretreatment with 0.35N HCl resulted in 67.3% and 50.5% reductions in gastric lesions induced by 0.6N and 1.0N HCl, respectively. Subdiaphragmatic vagotomy or intracisternal injection of TRH antibody increased gastric lesions induced by 0.6N HCl to 32.2% +/- 2.2% and 42.9% +/- 5.6%, respectively, and completely abolished the protective effect of 0.35N HCl pretreatment. Control or peptide YY antibody injected intracisternally did not alter the gastric protection induced by mild acid.

CONCLUSIONS

These results indicate that medullary TRH plays a role in the vagally mediated adaptive gastric protection induced by mild acid.

The influence of somatostatin on glucagon and pancreatic polypeptide secretion in the isolated perfused human pancreas

The current study was undertaken to determine whether intraislet somatostatin regulates glucagon or pancreatic polypeptide (PP) secretion in the human pancreas. A high-affinity, high-specificity monoclonal somatostatin antibody (CURE.S6) was used to immunoneutralize somatostatin in the isolated, perfused human pancreas. Single-pass perfusion was performed in pancreata obtained from cadaveric organ donors using a modified Krebs media with either 3.9 or 12.9 mM glucose. Sequential test periods separated by basal periods were performed with infusion of either exogenous somatostatin-14 (SS-14), CURE.S6, or a combined infusion. Infusion of SS-14 did not significantly alter glucagon or PP secretion during low-glucose or high-glucose perfusion. Immunoneutralization of intraislet somatostatin with CURE.S6 resulted in a significant increase of glucagon secretion under low-glucose conditions (delta X = 15 +/- 3 pM) (p < 0.05), but did not significantly effect glucagon secretion under high-glucose conditions (delta X = -2 +/- 3 pM) (p = NS). PP secretion remained unchanged during CURE.S6 infusion. Combined infusion of SS-14 and CURE.S6 did not significantly alter glucagon or PP secretion. The data suggest that intraislet somatostatin may have an inhibitory role in the regulation of glucagon secretion during low-glucose conditions and that intraislet somatostatin does not regulate PP secretion in the isolated, perfused human pancreas.

Medullary TRH is involved in gastric protection induced by low dose of kainic acid into the raphe pallidus

The gastroprotective effect of kainic acid microinjected into the raphe pallidus (Rpa) at a dose subthreshold to increase acid secretion was investigated in urethan-anesthetized rats. Kainic acid (25 pg/30 nl) microinjected into the Rpa inhibited by 65.8% gastric damage induced by intragastric ethanol (60%). No protection was observed when kainic acid was injected outside of the Rpa. The cytoprotective effect was completely abolished by thyrotropin-releasing hormone (TRH) antibody microinjected bilaterally (1.3 micrograms/site) into the dorsal motor nucleus of the vagus (DMN), indomethacin (5 mg/kg ip), and atropine (0.3 mg/kg sc). Microinjection of TRH antibody outside of the DMN or of control antibody into the DMN did not modify the protective action induced by kainic acid into the Rpa. The TRH antibody microinjected alone into the DMN did not alter the severity of the ethanol-induced gastric lesions. These data indicate that excitation of Rpa neurons by a low dose of kainic acid results in cytoprotection against ethanol lesions. Furthermore, this cytoprotection occurs as a result of TRH action in the DMN and activation of muscarinic and prostaglandin pathways.

Intracisternal injection of TRH antibody blocks gastric emptying stimulated by 2-deoxy-D-glucose in rats

We evaluated the effect of 2-deoxy-D-glucose (2-DG) on gastric emptying of a non nutrient solution in conscious rats using a Phenol red method. Intravenous injection of 2-deoxy-D-glucose dose-dependently increased the rate of gastric emptying. This stimulatory action of 2-DG was abolished by subdiaphragmatic vagotomy. Intracisternal injection of thyrotropin-releasing hormone (TRH) antibody blocked intracisternal TRH and intravenous 2-DG-induced enhancement of gastric emptying but not the stimulation of gastric emptying induced by intracisternal pancreatic polypeptide. The TRH antibody injected intraperitoneally had no effect. These results suggest that endogenous TRH in the brain is involved in vagal-dependent stimulation of gastric emptying by 2-DG.

Gastric mucosal damage induced by 2-deoxy-D-glucose involves medullary TRH in the rat

These studies examined the effect of 2-deoxy-D-glucose (2-DG) on gastric mucosal integrity. Intravenous administration of 2-DG in doses of 100 and 125 mg/kg dose-dependently produced multiple, hemorrhagic gastric mucosal lesions while 75 mg/kg of 2-DG failed to induce gastric lesions. Intracisternal injection of 2-DG in doses of 10 and 20 mg/kg also induced gastric mucosal damage in a dose-dependent manner whereas the injection of 5 mg/kg of 2-DG intracisternally did not induce the development of gastric lesions. Gastric mucosal damage by intravenous 2-DG was completely blocked by bilateral gastric branch vagotomy. Intracisternal but not intraperitoneal injection of anti-TRH antibody 8964 significantly reduced the severity of gastric mucosal lesions evoked by intravenous administration of 2-DG. These results suggest that 2-DG acts in the brain to induce gastric mucosal damage through vagal dependent pathways. Endogenous TRH in the central nervous system may be involved in the production of gastric mucosal damage by 2-DG.

Uremia in the rat affects gastric cell growth and differentiation

The aim of this study was to determine if hypertrophy of different tissues seen in uremic rats included gastrointestinal hypertrophy and an increase in parietal cell mass that might explain the increased acid secretion we previously reported. Chronic renal failure was induced by subtotal nephrectomy. Despite a lower total body weight, uremic rats had a significantly greater stomach weight (33%), corpus area (13%), corpus mucosal height (19%), and parietal (32%) and enterochromaffin-like (ECL, 54%) cell density, but a 16% decrease in mucous neck cell region height. These findings suggest that uremia leads to gastric stem cell stimulation with differentiation favoring parietal and ECL cells over mucous cells. In addition, in uremic rats there was an increase in height of the duodenal mucosa, but not of the ileal or transverse colon mucosa. In conclusion, the present study shows that uremia in the rat promotes hypertrophy of the stomach with cell differentiation favoring parietal cells over mucus cells. The increase in parietal cell mass may explain the increased acid secretion in these rats.

Parenterally or enterally administered anti-somatostatin antibody induces increased gastrin in suckling rats

This study demonstrates the effectiveness of parenteral and oral anti-somatostatin monoclonal antibody to stimulate gastrin cell activity in suckling rats. Intraperitoneal anti-somatostatin monoclonal antibody increased serum gastrin concentration (> 2-fold), and orally administered antibodies retained their neutralizing capabilities as demonstrated by a 30% induction of gastrin synthesis. Absorption of luminal monoclonal antibody was time dependent and saturable as demonstrated by measurement of serum murine immunoglobulin G and the subsequent effects on serum gastrin and antral gastrin mRNA concentrations. Enhanced gastrin synthesis after oral administration required whole antibody in that enterally delivered F(ab')2 fragments were not absorbed and did not increase serum gastrin concentrations. In addition, pretreatment with excess Fc fragments decreased monoclonal antibody absorption and eliminated the serum gastrin response to oral monoclonal antibody. These results demonstrate that orally administered murine anti-somatostatin monoclonal antibody was rapidly and efficiently absorbed via an Fc-dependent mechanism and retained immunoneutralizing activity against endogenous somatostatin, neutralizing its inhibition of gastrin cell activity. These results indicate that orally administered monoclonal antibodies could potentially be used to determine the role of other peptides and growth factors as potential physiological regulators during the suckling period of postnatal development.

Regulatory role of intraislet somatostatin on insulin secretion in the isolated perfused human pancreas

This study was undertaken to determine whether intraislet somatostatin inhibits insulin secretion in the human islet. A high-affinity monoclonal somatostatin antibody was used to immunoneutralize somatostatin in the isolated, perfused human pancreas. Single pass perfusion was performed in pancreata obtained from cadaveric organ donors using a modified Krebs medium with either 3.9 or 12.9 mM glucose. Sequential test periods separated by basal periods were performed with either somatostatin-14 (SS-14), somatostatin monoclonal antibody (CURE.S6), or a combined infusion. Infusion of SS-14 resulted in inhibition of insulin secretion under both low glucose (delta X = -712 +/- 212 pM) (p < 0.05) and high glucose (delta X = -21,913 +/- 10,003 pM) (p = 0.06) conditions. Immunoneutralization of intraislet somatostatin with CURE.S6 resulted in a significant increase in insulin secretion under both low glucose (454 +/- 162 pM) (p < 0.05) and high glucose (2,177 +/- 829 pM) (p < 0.05) conditions. Combined infusion of SS-14 and CURE.S6 resulted in a reversal of the inhibitory effect of exogenous SS-14. The data suggest that intraislet somatostatin has an inhibitory role in the regulation of insulin secretion in the human islet.

Raphe pallidus stimulation increases gastric contractility via TRH projections to the dorsal vagal complex in rats

The role of thyrotropin releasing hormone (TRH) in the dorsal vagal complex (DVC) in mediating the enhanced gastric contractility induced by glutamate (100 pmol) microinjected into the raphe pallidus (Rpa) was investigated in urethane-anesthetized rats acutely implanted with miniature strain gauge force transducers on the corpus of the stomach. Glutamate-induced stimulation of gastric contractility was dose-dependently inhibited by bilateral microinjection into the DVC of TRH antibody (0.17, 0.85 or 1.7 micrograms/100 nl/site) but not by vehicle. TRH antibody microinjected into the dorsal medullary reticular field had no effect. These data indicate that activation of Rpa neurons by glutamate increases gastric motor function through TRH release in the DVC.

Use of the Fab fragment for immunoneutralization of somatostatin in the isolated perfused human pancreas

The role of the somatostatin-secreting D cell in the islet remains controversial. The present study was undertaken to determine whether infusion of the Fab fragment of a highly sensitive somatostatin monoclonal antibody into the isolated, perfused human pancreas would influence insulin secretion. Single-pass perfusion was performed in pancreata obtained from cadaveric organ donors using a modified Krebs-media with 3.9 mM glucose. Sequential test periods separated by basal periods were performed with either somatostatin monoclonal antibody Fab fragment (SFab), somatostatin-14 (SS-14), or a combined infusion. Immunoneutralization of intraislet somatostatin with SFab resulted in a significant increase in both immunoreactive insulin (IRI) (1,122 +/- 497 pM) (p < 0.05) and immunoreactive C-peptide (IRC-P) secretion (146 +/- 53 pM) (p < 0.05). Infusion of SS-14 resulted in inhibition of both IRI secretion (-3,372 +/- 1,360 pM) (p < 0.05) and IRC-P secretion (-708 +/- 220 pM) (p < 0.05). Combined infusion of SFab and SS-14 reversed the inhibitory effect of exogenous SS-14 on IRI and IRC-P secretion. The data suggest that intraislet somatostatin has an inhibitory role in the regulation of B-cell secretion in the human islet and demonstrates that the Fab fragment of the somatostatin monoclonal antibody is an effective tool for immunoneutralization studies in the human pancreas. In addition, immunostaining of the donor pancreata demonstrated the presence of somatostatin-immunoreactive endocrine cells interspersed throughout the islet core and mantle. The demonstrated proximity of somatostatin-immunoreactive endocrine cells to B cells lends anatomic support to the concept that intraislet somatostatin influences insulin secretion in the human islet.

TRH in dorsal vagal complex mediates acid response to excitation of raphe pallidus neurons in rats

The role of thyrotropin-releasing hormone (TRH) in the dorsal vagal complex (DVC) in the acid response to excitation of raphe pallidus neurons was investigated in urethan-anesthetized rats with gastric fistula. Kainic acid (0.19 microgram/30 nl) microinjected into the raphe pallidus stimulated gastric acid secretion. The response was prevented by vagotomy. A specific polyclonal TRH antibody, 8964, was raised and characterized (50% inhibitory dose for TRH was 80 pg/ml at an antibody final dilution of 1:10(5)). The TRH antibody injected intracisternally blocked the acid response to intracisternal TRH, but not that of the TRH analogue RX-77368. The TRH antibody (0.33, 0.65, or 1.3 micrograms.100 nl-1.site-1) microinjected bilaterally into the DVC prevented dose dependently by 31, 60, and 76%, respectively, the increase in acid secretion induced by kainic acid injected into the raphe pallidus. The TRH antibody (1.3 microgram/site) microinjected into medullary sites outside of the DVC had no effect. These data indicate that excitation of raphe pallidus neurons induces a vagal-dependent stimulation of gastric acid secretion that is mediated by endogenous TRH in the DVC. TRH neurons in the raphe pallidus projecting to the DVC may have a physiological relevance in the vagal regulation of gastric function.

Intestinal fat does not inhibit gastric function through a hormonal somatostatin mechanism in dogs

In awake dogs with chronic gastric, duodenal, and jejunal fistulas, F(ab)1 fragments of somatostatin monoclonal antibody (mAb S607) were administered intravenously (IV) to test the hypothesis that intraintestinal lipid inhibits peptone-stimulated gastric acid secretion and emptying by a hormonal somatostatin mechanism. Plasma somatostatin was increased significantly by duodenal and jejunal perfusion with 20% lipid. Somatostatin administered IV caused dose-dependent inhibition of meal-stimulated gastric acid secretion and gastric emptying similar to that seen after intestinal perfusion with lipid. Administration of mAb S607 F(ab)1 fragments significantly reversed somatostatin (400 pmol.kg-1.h-1, IV)-induced inhibition of peptone-stimulated acid output and gastric emptying. Acid output inhibited by intraduodenal lipid was reversed partially after F(ab)1 administration, but the inhibitory effect of intrajejunal lipid was not altered. Inhibition of acid secretion by IV somatostatin and by intraintestinal fat was not caused by a decrease in circulating gastrin concentrations. Gastric emptying delayed by intraintestinal lipid was unaffected by antibody administration. Somatostatin does not appear to be a major hormonal mediator of intestinal fat-induced inhibition of gastric acid secretion or delayed gastric emptying in dogs.