Inflammatory bowel disease and irritable bowel syndrome: separate or unified?

Berberine Administration in Treatment of Colitis: A Review

Berberine (Brb) is one of the well-known naturally occurring compounds exclusively found in Berberis vulgaris and other members of this family, such as Berberis aristata, Berberis aroatica, and Berberis aquifolium. This plant-derived natural compound has a variety of therapeutic impacts, including anti-oxidant, anti-inflammatory, anti-diabetic, and anti-tumor. Multiple studies have demonstrated that Brb has great anti-inflammatory activity and is capable of reducing the levels of proinflammatory cytokines, while it enhances the concentrations of anti-inflammatory cytokines, making it suitable for the treatment of inflammatory disorders. Colitis is an inflammatory bowel disease with chronic nature. Several factors are involved in the development of colitis and it appears that inflammation and oxidative stress are the most important ones. With respect to the anti-inflammatory and antioxidant effects of Brb, its administration seems to be beneficial in the treatment of colitis. In the present review, the protective effects of Brb in colitis treatment and its impact on molecular pathways are discussed.

Berberine prevents stress-induced gut inflammation and visceral hypersensitivity and reduces intestinal motility in rats

BACKGROUND

Irritable bowel syndrome (IBS) is a common chronic non-organic disease of the digestive system. Berberine (BBR) has been used to treat patients with IBS, but the underlying therapeutic mechanism is little understood. We believe that BBR achieves its therapeutic effect on IBS by preventing stress intestinal inflammation and visceral hypersensitivity and reducing bowel motility.

AIM

To test the hypothesis that BBR achieves its therapeutic effect on IBS by preventing subclinical inflammation of the intestinal mucosa and reducing visceral hypersensitivity and intestinal motility.

METHODS

IBS was induced in rats via water avoidance stress (WAS). qRT-PCR and histological analyses were used to evaluate the levels of cytokines and mucosal inflammation, respectively. Modified ELISA and qRT-PCR were used to evaluate the nuclear factor kappa-B (NF-κB) signal transduction pathway. Colorectal distention test, gastrointestinal transit measurement, Western blot, and qRT-PCR were used to analyze visceral sensitivity, intestinal motility, the expression of C-kit (marker of Cajal mesenchymal cells), and the expression of brain derived neurotrophic factor (BDNF) and its receptor TrkB.

RESULTS

WAS led to mucosal inflammation, visceral hyperalgesia, and high intestinal motility. Oral administration of BBR inhibited the NF-κB signal transduction pathway, reduced the expression of pro-inflammatory cytokines [interleukin (IL)-1β, IL-6, interferon-γ, and tumor necrosis factor-α], promoted the expression of anti-inflammatory cytokines (IL-10 and transforming growth factor-β), and improved the terminal ileum tissue inflammation. BBR inhibited the expression of BDNF, TrkB, and C-kit in IBS rats, leading to the reduction of intestinal motility and visceral hypersensitivity. The therapeutic effect of BBR at a high dose (100 mg/kg) was superior to than that of the low-dose (25 mg/kg) group.

CONCLUSION

BBR reduces intestinal mucosal inflammation by inhibiting the intestinal NF-κB signal pathway in the IBS rats. BBR reduces the expression of BDNF, its receptor TrkB, and C-kit. BBR also reduces intestinal motility and visceral sensitivity to achieve its therapeutic effect on IBS.

An exploration of the barriers to the confident diagnosis of irritable bowel syndrome: A survey among general practitioners, gastroenterologists and experts in five European countries

BACKGROUND

The diagnostic processes for chronic abdominal conditions are challenging. Despite their tendency for diagnostic tests in patients with irritable bowel syndrome (IBS) symptoms, clinicians are encouraged to make a positive diagnosis based on symptom criteria without alarm signs. We explored how European physicians diagnose and manage patients suffering from IBS.

METHODS

We conducted a vignette-based survey to evaluate the diagnostic approaches in four standardized patients with IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), inflammatory bowel disease (IBD) and chronic constipation (CC). General practitioners (GP, n = 104), gastroenterologists (GE, n = 100) and IBS experts (n = 25) from five European countries participated.

RESULTS

Experts showed the highest rates of correct diagnoses (88%-92%) for all cases except CC (only 60%) and were more prone to a positive diagnosis (64%/68% in IBS-C/CC), whereas GEs and GPs tended toward a diagnosis by exclusion (63%/63% and 62%/60% in IBS-C/CC). In the CC vignette, conducting tests was more frequent than prescribing treatment among 44% experts, 63% GEs and 36% GPs. The diagnosis of IBD presented little difficulty for any of the participants.

CONCLUSIONS

This study highlights the difficulties in confidently diagnosing chronic functional bowel conditions, especially for non-experts, whereas IBD caused little difficulty. Differentiating between IBS-C and CC seemed particularly challenging, even for experts.

Neurokinin-1-receptor antagonism decreases anxiety and emotional arousal circuit response to noxious visceral distension in women with irritable bowel syndrome: a pilot study

BACKGROUND

Irritable bowel syndrome is characterised by chronic abdominal pain and frequent comorbid anxiety. The substance P ⁄ neurokinin-1 receptor system is implicated in the regulation of both pain and anxiety, suggesting a potential therapeutic target in IBS.

AIM

To determine whether inhibition of the neurokinin-1 receptor (NK1R) will change pain ratings and brain responses to experimental visceral pain and anxiety symptoms in women with IBS or not.

METHODS

Rome II positive IBS women were recruited for a double-blind, placebo-controlled, cross-over study of NK1R antagonist AV608. Treatment periods were 3 weeks with a 2-week washout period. Functional MRI during a visceral distension paradigm was performed before first treatment and after treatment blocks. SPM8 was used to compare brain activity during painful and nonpainful visceral stimuli in regions associated with emotional arousal and interoception. Negative affect, anxiety symptoms and pain ratings were assessed.

RESULTS

Eleven subjects completed the study and eight subjects provided fMRI data. AV608, compared with placebo, was associated with reduced anxiety, negative affect, and pain ratings. During AV608 treatment, the amygdala, hippocampus and anterior cingulate gyrus showed decreased activity during visceral distension. AV608 was also associated with decreases in activity in brain regions associated with interoception (posterior insula, anterior mid-cingulate gyrus).

CONCLUSIONS

Chronic treatment with AV608 in IBS is associated with improved mood and pain ratings and activity of emotional arousal related brain regions. This suggests that further exploration of NK1R antagonists is warranted in visceral pain disorders, particularly in patients with comorbid anxiety symptoms.

Dextran sulfate sodium-induced low grade mucosal inflammation activates visceral hypersensitivity in rats

AIM: To investigate the role of low grade mucosal inflammation (LGMI) induced by dextran sulfate sodium (DSS) in visceral sensitivity of the rats.

METHODS: Forty healthy male Sprague-Dawley (SD) rats were randomly divided into LGMI group and control group (n = 20). LGMI was induced by addition of 15 g/L DSS to drinking water for 7 d, and then distilled water for another 7 d. The control group rats were given distilled water alone. At the 14th day, abdominal withdrawal reflex (AWR) and myoelectric amplitude (MA) of the oblique externus abdominis muscle were recorded respectively after colonic distention by balloon with ascending internal pressure from 20 mmHg to 80 mmHg. The colonic tissue samples were taken for histopathologic examinations (HE staining), and the expressions of c-fos, substance P (SP) and calcitonin gene-related peptide (CGRP) in the intumescentia lumbalis were detected using immunohistochemistry.

RESULTS: The colonic mucosal inflammation score in LGMI rats was 1.56 ± 0.78, significantly higher than that in control rats (0.46 ± 0.54, P = 0.003). Neither the AWR score nor the MA had significant difference between the two groups when the internal balloon pressure was 20 mmHg. When the pressure was up to 40, 60, 80 mmHg, the AWR score and the MA in LGMI rats were significantly higher than those in the control group (all P < 0.05). The expression of c-fos, SP and CGRP in LGMI were respectively higher than those in controls (165.26 ± 10.12 vs 126.52 ± 11.48, 134.28 ± 10.62 vs 120.82 ± 8.92, 157.66 ± 6.25 vs 118.67 ± 5.68, all P < 0.01).

CONCLUSION: Low grade inflammation of colonic mucous induced by DSS in rats may promote expression of the c-Fos, SP, and CGRP in the intumescentia lumbalis, and activate the visceral hypersensitivity, which underlies IBS.

Inhibition of endothelial cell adhesion molecule expression improves colonic hyperalgaesia

Leucocyte-endothelial cell interactions are prerequisite to leucocyte infiltration and intestinal inflammation. GI270384X is a novel inhibitor of ICAM-1 and E-selectin expression and inhibits leucocyte adhesion and improves experimental colitis. We hypothesized that GI270384X maybe effective in treatment of visceral hyperalgaesia. Visceromotor behavioural responses to colorectal distension (CRD) were obtained in naïve rats or rats treated with zymosan (3 h) or 2,4,6-trinitrobenzene sulphonic acid (TNBS) (4 and 30 days) or rats exposed to acute restraint stress. Studies were also performed in a high-anxiety genetic model of colonic hyperalgaesia using Wistar-Kyoto (WKY) rats. Rats were treated orally with GI270384X or vehicle either prior to or after the administration of sensitizing stimulus. The visceromotor response to CRD was significantly enhanced in all models. GI270384X attenuated the enhanced responses to distension induced by inflammatory stimuli (TNBS and zymosan) and in the high-anxiety WKY rats; however, the drug did not inhibit the hypersensitivity induced by acute restraint stress. GI270384X was most potent in the models of acute inflammatory hyperalgaesia with a minimum efficacious dose (MED) of 0.3 and 1 mg kg(-1) observed in the TNBS and zymosan models respectively. The compound was less potent in the chronic and postinflammatory models with an MED of 10 and 30 mg kg(-1) observed in the WKY and 30-day TNBS models respectively. These findings show for the first time that inhibition of leucocyte-endothelial cell interactions can have a beneficial effect on visceral hyperalgaesia associated with inflammatory and chronic anxiety states, but is less effective against stress-associated visceral hyperalgaesia.

Melatonin and ulcerative colitis: evidence, biological mechanisms, and future research

Ulcerative colitis (UC) is an inflammatory bowel disease that afflicts up to 1 million people in the US. Current treatments for UC are mostly nonspecific, not always effective, and often accompanied by serious side effects. Therefore, there is considerable interest in finding alternative and more tolerable treatments for this disease. Physiologic data suggest that melatonin is an important regulator of both inflammation and motility in the gastrointestinal tract, and data from in vitro studies, animal experiments, and limited studies in humans suggest that supplemental melatonin may have an ameliorative effect on colitis. In this review we summarize the evidence regarding melatonin as a possible therapeutic agent in UC and discuss possible biological mechanisms and directions for future research.

[Socioeconomic and nutritional profile of patients with inflammatory bowel disease at a university hospital]

BACKGROUND

Inflammatory bowel diseases include chronic and relapsing inflammatory disorders, represented by ulcerative proctocolitis and Crohns disease, commonly associated with malnutrition.

AIM

Characterize the nutritional and socioeconomic profile of patients hospitalized at the Pernambuco "Hospital das Clínicas", Recife, PE, Brazil.

METHODS

Cross-sectional study carried out at the gastroenterology clinic, which was previously approved by the Ethics Commission for studies involving human beings. The methods included clinical history data, socioeconomic conditions and nutritional assessment. Data were subject to statistical analysis (Students t test for equal and unequal variables).

RESULTS

The sample consisted of 24 male and female patients, with a mean age of 43.83 +/- 16.13 years, mostly married, coming from Recife, with low income, who lived in their own house with relatives. We found a higher prevalence of ulcerative proctocolitis (62.5%), with diagnosis time of more than 5 years, symptoms of abdominal pain, bloody-mucous diarrhea with 6-9 evacuations/day, with the distal colon being the most affected part. Osteoporosis was present in 26.7% of cases. Nutritional status was assessed through the body mass index. The weight loss percentage corresponded to 41.7% and 70.8%, respectively, classified as malnourished, associated or not with high prevalence levels of anemia, hypoalbuminemia and hypocalcemia. Gender correlation evidenced higher triceps fold and arm circumference values in men.

CONCLUSIONS

Despite the study limitations, data suggest relevant information about the occurrence of these diseases in the northeast of Brazil, as well as about its frequent association with important nutritional deficiencies.

Gastrointestinal microbiota in irritable bowel syndrome: their role in its pathogenesis and treatment

Irritable bowel syndrome (IBS) is a chronic disorder characterized by abdominal pain, change in bowel habit, and bloating. It has traditionally been viewed as a disorder of visceral hypersensitivity heavily influenced by stress, and therefore therapeutic strategies to date have largely reflected this. However, more recently, there is good evidence for a role of the gastrointestinal (GI) microbiota in its pathogenesis. Changes in fecal microbiota, the use of probiotics, the phenomenon of postinfectious IBS, and the recognition of an upregulated host immune system response suggest that an interaction between the host and GI microbiota may be important in the pathogenesis of IBS. This article explores the role of the GI microbiota in IBS and how their modification might lead to therapeutic benefit.

Experimental gastritis in mice enhances anxiety in a gender-related manner

There is a gender-related comorbidity of pain-related and inflammatory bowel diseases with psychiatric diseases. Since the impact of experimental gastrointestinal inflammation on the emotional-affective behavior is little known, we examined whether experimental gastritis modifies anxiety, stress coping and circulating corticosterone in male and female Him:OF1 mice. Gastritis was induced by adding iodoacetamide (0.1%) to the drinking water for at least 7 days. Inflammation was assessed by gastric histology and myeloperoxidase activity, circulating corticosterone determined by enzyme immunoassay, anxiety-related behavior evaluated with the elevated plus maze and stress-induced hyperthermia tests, and depression-like behavior estimated with the tail suspension test. Iodoacetamide-induced gastritis was associated with gastric mucosal surface damage and an increase in gastric myeloperoxidase activity, this increase being significantly larger in female mice than in male mice. The rectal temperature of male mice treated with iodoacetamide was enhanced, whereas that of female mice was diminished. The circulating levels of corticosterone were reduced by 65% in female mice treated with iodoacetamide but did not significantly change in male mice. On the behavioral level, iodoacetamide treatment caused a decrease in nocturnal home-cage activity, drinking and feeding. While depression-related behavior remained unaltered following induction of gastritis, behavioral indices of anxiety were significantly enhanced in female but not male mice. There was no correlation between the estrous cycle and anxiety as well as circulating corticosterone. Radiotracer experiments revealed that iodoacetamide did not readily enter the brain, the blood-brain ratio being 20:1. Collectively, these data show that iodoacetamide treatment causes gastritis in a gender-related manner, its severity being significantly greater in female than in male mice. The induction of gastritis in female mice is associated with a reduction of circulating corticosterone and an enforcement of behavioral indices of anxiety. Gastric inflammation thus has a distinct gender-dependent influence on emotional-affective behavior and its neuroendocrine control.

Bowel Obsession Syndrome in a Patient With Ulcerative Colitis

Gastroenterologists are often faced with the diagnostic problem of differentiating acute symptoms of ulcerative colitis from functional intestinal disorders. Bowel obsession syndrome (BOS) is an OCD-like, functional syndrome characterized by fear of fecal incontinence and compulsive behaviors of evacuation-checking. Only sparse case studies on treatment of BOS with antidepressants have been published. This is the first study on successful psychotherapy of a male patient with ulcerative colitis overlapping functional bowel symptoms and marked symptoms of BOS. Clinical recognition of BOS may help clinicians in differential diagnosis, prevent unnecessary investigations, and give patients the most appropriate treatment.

Interaction between interleukin-17-producing CD4+ T cells and colonic subepithelial myofibroblasts: what are they doing in mucosal inflammation?

Recent studies have shown alterations and activations in the mucosal immune system in patients with irritable bowel syndrome (IBS) as well as in those with inflammatory bowel disease (IBD). As one of effectors of mucosal inflammation, a new lineage of effector CD4+ T cells characterized by production of interleukin (IL)-17, the T-helper (Th)-17 lineage, was recently described. Th-17 cells are developmentally and functionally distinct from Th1 and Th2 cells. Here, we discuss the recent concept of low-grade inflammation as a factor associated with the pathophysiology of IBS. Furthermore, based on the data from our laboratory, interaction between Th-17 cells and colonic subepithelial myofibroblasts may play an important role in the pathophysiology of IBS and IBD.

Treatment of irritable bowel syndrome in outpatients with inflammatory bowel disease using a food and beverage intolerance, food and beverage avoidance diet

Irritable bowel syndrome (IBS) in the outpatient with chronic inflammatory bowel disease (IBD) is a difficult but important challenge to recognize and treat. It is very helpful to have effective treatment approaches for IBS that are practical and use minimal medications. Because of the underlying chronic inflammation in IBD, IBS symptoms occur with increased frequency and severity, secondary to increased hypersensitivity to foods and beverages that stimulate the gastrointestinal tract. This paper discusses how to treat IBS in the IBD outpatient, with emphasis on using a food and beverage intolerance, avoidance diet. The adverse effects of many foods and beverages are amount dependent and can be delayed, additive, and cumulative. The specific types of foods and beverages that can induce IBS symptoms include milk and milk containing products; caffeine containing products; alcoholic beverages; fruits; fruit juices; spices; seasonings; diet beverages; diet foods; diet candies; diet gum; fast foods; condiments; fried foods; fatty foods; multigrain breads; sourdough breads; bagels; salads; salad dressings; vegetables; beans; red meats; gravies; spaghetti sauce; stews; nuts; popcorn; high fiber; and cookies, crackers, pretzels, cakes, and pies. The types of foods and beverages that are better tolerated include water; rice; plain pasta or noodles; baked or broiled potatoes; white breads; plain fish, chicken, turkey, or ham; eggs; dry cereals; soy or rice based products; peas; applesauce; cantaloupe; watermelon; fruit cocktail; margarine; jams; jellies; and peanut butter. Handouts that were developed based upon what worsens or helps IBS symptoms in patients are included to help patients learn which foods and beverages to avoid and which are better tolerated.

Disturbed in vitro adrenergic modulation of cytokine production in inflammatory bowel diseases in remission

OBJECTIVE

Psychological stress has been implicated in the pathophysiology of both inflammatory and functional gastrointestinal (GI) diseases. The goal of this study was to address neuroendocrine modulation of cytokine production by peripheral blood cells in GI diseases.

METHODS

We analyzed the in vitro effects of the beta-adrenergic agonist terbutaline and the glucocorticoid agonist dexamethasone on TNF-alpha and IL-10 production by LPS-stimulated monocytes in whole cell blood cultures in patients with inflammatory bowel diseases in remission (N=10), diarrhoea-predominant irritable bowel syndrome (IBS, N=12), patients with a recent gastroenteritis (post-infectious group, N=10), and healthy controls (N=15).

RESULTS

In response to terbutaline, there was a significant increase in IL-10 production (concentration effect: p<0.05), which was diminished in IBD (group effect: p<0.01), comparable in IBS and controls, but enhanced in the post-infectious group (group x concentration effect: p<0.05). In contrast, terbutaline resulted in a concentration-dependent suppression of TNF-alpha production, which was comparable in all groups. Dexamethasone suppressed TNF-alpha production in a dose-dependent manner in all groups, but this effect was significantly more pronounced in post-infectious subjects (group effect: p<0.05).

CONCLUSIONS

In IBD, disturbed adrenergic regulation of IL-10 could be part of the mechanism(s) underlying the modulation of disease activity by psychological stress. Diarrhoea-predominant IBS was not associated with altered adrenergic or glucocorticoid regulation of cytokine production by peripheral blood cells, whereas a recent history of gastroenteritis was associated with disturbed neuroendocrine modulation of cytokine production, which may play role in the pathophysiology of post-infectious IBS.

Psychoneuroimmunology and occupational therapy for inflammatory disorders

The occupational therapy profession was founded in 1917 on the notion that occupations contribute to psychological well being and physical adaptation. The credibility of occupational therapy has been threatened because the scientific basis of this notion is not always evident. The focus of occupational therapy in many physical settings has therefore shifted away from its original ethos towards one of physical problem solving and discharge facilitation.

Psychoneuroimmunology (PNI) is a developing branch of science that provides a theoretical framework to support the profession’s return to its original ethos of using occupations to promote health. This paper is an analysis of psychoneuroimmunological evidence to support occupational therapy for inflammatory disorders. A broad literature search revealed mind-body inflammatory pathways including anatomical links, nerve growth factor, adrenocorticotrophin, cortisol, somatostatin and substance-P.

Brain-gut connections in functional GI disorders: anatomic and physiologic relationships

Understanding the neural regulation of gut function and sensation makes it easier to understand the interrelatedness of emotionality, symptom-attentive behavior or hypervigilance, gut function and pain. The gut and the brain are highly integrated and communicate in a bidirectional fashion largely through the ANS and HPA axis. Within the CNS, the locus of gut control is chiefly within the limbic system, a region of the mammalian brain responsible for both the internal and external homeostasis of the organism. The limbic system also plays a central role in emotionality, which is a nonverbal system that facilitates survival and threat avoidance, social interaction and learning. The generation of emotion and associated physiologic changes are the work of the limbic system and, from a neuroanatomic perspective, the 'mind-body interaction' may largely arise in this region. Finally, the limbic system is also involved in the 'top down' modulation of visceral pain transmission as well as visceral perception. A better understanding of the interactions of the CNS, ENS and enteric immune system will significantly improve our understanding of 'functional' disorders and allow for a more pathophysiologic definition of categories of patients currently lumped under the broad umbrella of FGID.

Detection of inflammatory markers in stools from patients with irritable bowel syndrome and collagenous colitis

OBJECTIVE

Irritable bowel syndrome (IBS) and collagenous colitis (CC) share chronically recurring symptoms of altered bowel habits associated with abdominal pain or discomfort. The aims of the present study were to investigate whether inflammatory markers could be detected in faeces from patients with IBS and CC, and to elucidate whether such analyses could be used as non-invasive tools to distinguish between these disorders.

MATERIAL AND METHODS

Stool samples were obtained from 18 patients with CC, 46 patients with IBS and 20 healthy controls (HC). Eosinophil protein X (EPX), myeloperoxidase (MPO), tryptase, interleukin-1 beta (IL-1beta) and tumour necrosis factor alpha (TNFalpha) were measured in supernatants from processed faeces using immunoassays.

RESULTS

EPX levels were enhanced in faeces from CC patients (median 3.8 microg/g (0.47-16.2)) compared to patients with IBS (0.44 microg/g (0.25-1.8)), p<0.001, and HC (0.46 microg/g (0.21-1.3)), p<0.001. In addition, MPO was increased in CC patients (11.7 microg/g (2.0-124)) compared to IBS patients (1.7 microg/g (0.81-5.2)), p<0.01, and HC (2.5 microg/g (1.1-6.3)), p<0.05. Tryptase was found in 9/18 patients with CC, 6/46 with IBS and 1/19 HC. IL-1beta was only enhanced in 2/11 CC patients and TNFalpha was not detected in any sample.

CONCLUSIONS

Increased levels of EPX, MPO and tryptase were observed in stools from collagenous colitis patients, whereas the levels in IBS patients did not differ from healthy controls. Our data suggest that faecal markers could be used as part of the clinical work-up to determine which patients should be biopsied and evaluated for collagenous colitis.

Differences in brain responses to visceral pain between patients with irritable bowel syndrome and ulcerative colitis

Patients with mild chronic inflammation of the rectum or ileum have reduced perceptual responses to rectosigmoid distension compared to patients with irritable bowel syndrome (IBS). The current study sought to identify differences in regional cerebral blood flow (rCBF) during rectal distension, which might correspond to these perceptual differences. In 8 male ulcerative colitis (UC) patients with quiescent disease, 7 male IBS patients and 7 healthy male controls, rCBF was assessed using 15O-water positron emission tomography at baseline and during actual and anticipated but undelivered rectal distensions. No group differences were seen in anterior insula and dorsal anterior cingulate cortex (dACC), two regions consistently activated by painful intestinal stimuli. However, IBS patients showed greater activation of the amygdala, rostroventral ACC, and dorsomedial frontal cortical regions. In contrast, no significant differences were observed between UC and controls. When these two non-IBS groups were combined, functional connectivity analyses showed that right lateral frontal cortex (RLFC) activation positively correlated with activation of the dorsal pons/periaqueductal gray, a key region involved in endogenous pain inhibition. According to the connectivity analysis, this effect was mediated by inhibition of medial frontal cortex by the RLFC. Chronic colonic inflammation is not necessarily associated with increased visceral afferent input to the brain during rectal distension. In the sample studied, the primary difference between functional and quiescent inflammatory disease of the colon was in terms of greater activation of limbic/paralimbic circuits in IBS, and inhibition of these circuits in UC and controls by the RLFC.

An acute stressor enhances sensitivity to a chemical irritant and increases 51CrEDTA permeability of the colon in adult rats

We investigated the effect of prior acute stress on colonic permeability induced by a chemical irritant known to induce symptoms similar to inflammatory bowel disease in rodents. Adult male rats (n = 12) were stressed by a single session of ten unpredictable, uncontrollable foot shocks, and half were home cage controls (n = 12). Twenty-nine days later, half of each treatment group was exposed to 4% DSS (dextran sulphate sodium) solution in their drinking water for 48 hours while half received pure water over two periods separated by 17 days. After food deprivation overnight and light isoflurane anaesthesia the following morning, the animals were given a colonic infusion of 2000 nCi (nanocurie) 51CrEDTA (51Cr-labelled ethylenediaminetetraacetic acid) and then placed individually in metabolic cages for a six hours continuous urine collection. Radioactivity in urine was measured by a gamma counter and percentage recovery of 51CrEDTA calculated as an indicator of colonic mucosal permeability. Results concluded that pre-shocked animals exposed to DSS showed significantly higher mucosal permeability than the pre-shocked animals given water, and the non-shocked animals given either DSS or water. Pre-shock in combination with two exposures to a chemical irritant separated by 17 days had a pronounced effect on colonic permeability, indicating that stress should be considered a possible initiating or contributory factor to increased intestinal permeability related to a mucosal challenge.

Update on the etiology, pathogenesis and diagnosis of ulcerative colitis

Evidence is accumulating that both genetic and environmental factors contribute to ulcerative colitis. The most consistent genetic associations have been shown for the MHC locus HLA Class II alleles, but the interleukin-1 family of genes and the multidrug resistance gene MDR1 have also been implicated as genetic susceptibility factors for the development of disease. In addition, there is a relationship between ulcerative colitis and bacterial flora, with an increased number of adherent Bacteroides spp. and Enterobacteriaceae spp. present in inflamed bowel segments. Conversely, cigarette smoking and appendectomy have both been shown to protect against the development of ulcerative colitis. Despite our improved understanding of the genetics and inflammatory mechanisms that underpin this disease, however, the etiology and pathogenesis of ulcerative colitis remain undefined. The diagnosis of ulcerative colitis is being aided by recent advances in diagnostic strategies, including the detection of fecal and serologic markers and the use of wireless capsule endoscopy, but, in the absence of a pathognomonic marker, the definition of this disease remains based on well-established clinical, endoscopic and histologic criteria. In particular, it is difficult to discriminate ulcerative colitis from other forms of colitis, including Crohn's disease, and there seems to be a growing overlap of pathophysiologic processes between ulcerative colitis and post-infectious irritable bowel syndrome. Patients who remain indeterminate between ulcerative colitis and Crohn's disease also continue to be a diagnostic challenge.