Recent developments in "nonspecific" inflammatory bowel disease (first of two parts)

The interplay of gut microbiota between donors and recipients determines the efficacy of fecal microbiota transplantation

Fecal microbiota transplantation (FMT) is a promising treatment for microbiota dysbiosis associated diseases, such as Clostridioides difficile infection (CDI) and inflammatory bowel disease (IBD). The engraftment of donor bacteria is essential for the effectiveness of FMT, which to some extent depends on the matching of donors and recipients. However, how different types of donor-derived bacteria affect FMT efficacy has not been fully dissected. We recruited two longitudinal IBD cohorts of 103 FMT recipients and further analyzed 1,280 microbiota datasets from 14 public CDI and IBD studies to uncover the effect of donor-derived microbiota in recipients. We found that two enterotypes, RCPT/E and RCPT/B (dominated by Enterobacteriaceae and Bacteroides, respectively), consistently exist in both CDI and IBD patients. Based on a time-course-based multi-cohort analysis of FMT fecal samples, we observed the interplay between recipient and donor-derived microbiota during FMT, in which the FMT outcome was significantly associated with the enterotype and microbiota distance between donor and recipient after FMT. We proposed a new measurement, the ratio of colonizers to residents after FMT (C2R), to quantify the engraftment of donor-derived bacteria in the recipients, and then constructed an enterotype-based statistical model for donor-recipient matching, which was validated by both cross-validation and an additional IBD FMT cohort (n = 42). We believe that with the accumulation of FMT multi-omics datasets, machine learning-based methods will be helpful for rational donor selection for improving efficacy and precision FMT practices.

Inflammatory bowel disease and the lung in paediatric patients

The prevalence of inflammatory bowel disease (IBD) has increased over the past 20 years. Pulmonary involvement in paediatric IBD is rare but may be missed since the spectrum of symptoms is broad and mimics other diseases. The most important differential diagnoses of pulmonary manifestations of IBD are infections and therapy-related side-effects. There is no gold standard to diagnose respiratory manifestations in children with IBD. Diagnostic tests should be chosen according to history and clinical presentation. Treatment of respiratory manifestations of IBD includes inhaled or oral corticosteroids and initiation or step-up of immunomodulatory IBD therapies.

Pulmonary involvement in paediatric IBD is rare but may be underdiagnosed. The spectrum of symptoms is broad and mimics other diseases. The differentiation between IBD-related and drug-induced pulmonary manifestation can be challenging.https://bit.ly/3uZBvpA

Biochemical and histopathological effects of low dose vanadium in the healing of acetic acid-induced colitis in male wistar rats

OBJECTIVES

Vanadium has been reported to possess relevant therapeutic properties such as anti-diabetic and anti-tumoral. This study aimed at determining the effects of vanadium on experimentally induced colitis in rats.

METHODS

Forty-five male Wistar rats (103 ± 3.90 g, n=15) were used for this study and were divided into three groups. Group 1 (Untreated control) had nothing added to their drinking, while groups 2 and 3 received sodium metavanadate at a dose of 50 and 200 mg/L respectively in their drinking water for 10 weeks. Colitis was thereafter induced by intra colonic administration of 1.50 mL of 6% acetic acid. Animals were sacrificed on day 0 (pre-induction), three- and seven-days post induction. Blood samples were collected for haematological variables and the distal 8 cm of the colon was collected for macroscopic, histological and biochemical (malondialdehyde-MDA, superoxide dismutase-SOD, catalase-CAT, glutathione peroxidase- GPx and nitrite concentration- NO) assessment.

RESULTS

Low dose vanadium proved beneficial in ameliorating acetic acid-induced colitis by improving both histopathological and haematological changes. Gross observation showed a faster healing rate in vanadium treated groups (50 and 200 mg/L) compared with untreated control at day 3 (40 and 26.20 vs. 2.50%) and day 7 (80 and 66.70 vs. 42%) respectively. Vanadium also appears to exert its beneficial effects on acetic acid-induced colitis via up regulation of antioxidant enzymes (SOD, CAT, GPx) and NO while decreasing the over production of MDA.

CONCLUSIONS

Vanadium at small concentration functions as an essential trace element and may be able to promote healing process during ulcerative colitis.

Nonalcoholic fatty liver disease in patients with inflammatory bowel disease: Beyond the natural history

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a frequently reported condition in patients with inflammatory bowel disease (IBD). Both intestinal inflammation and metabolic factors are believed to contribute to the pathogenesis of IBD-associated NAFLD.

AIM

To evaluate the prevalence of steatosis and liver fibrosis (LF) in a cohort of IBD patients and the identification of metabolic- and IBD-related risk factors for NAFLD and LF.

METHODS

IBD patients were consecutively enrolled from December 2016 to January 2018. Demographic, anthropometric and biochemical data were collected so as eating habits. Abdominal ultrasound and transient elastography were performed to evaluate the presence of NAFLD and LF respectively.

RESULTS

A total of 178 consecutive patients were enrolled and included in the analysis (95 Ulcerative colitis, 83 Crohn’s disease). NAFLD was detected by imaging in 72 (40.4%) patients. Comparison between patients with and without NAFLD showed no significant differences in terms of IBD severity, disease duration, location/extension, use of IBD-related medications (i.e., steroids, anti-TNFs, and immunomodulators) and surgery. NAFLD was significantly associated with the presence of metabolic syndrome [MetS; odds ratio (OR): 4.13, P = 0.001] and obesity defined by body mass index (OR: 9.21, P = 0.0002). IBD patients with NAFLD showed higher caloric intake and lipid consumption than those without NAFLD, regardless disease activity. At the multivariate analysis, male sex, advanced age and high lipid consumption were independent risk factors for the development of NAFLD. An increased liver stiffness was detected in 21 patients (16%) and the presence of MetS was the only relevant factor associated to LF (OR: 3.40, P = 0.01).

CONCLUSION

In this study, we demonstrate that risk factors for NAFLD and LF in the IBD population do not differ from those in the general population.

Meta-analysis of gut microbiome studies identifies disease-specific and shared responses

Hundreds of clinical studies have demonstrated associations between the human microbiome and disease, yet fundamental questions remain on how we can generalize this knowledge. Results from individual studies can be inconsistent, and comparing published data is further complicated by a lack of standard processing and analysis methods. Here we introduce the MicrobiomeHD database, which includes 28 published case–control gut microbiome studies spanning ten diseases. We perform a cross-disease meta-analysis of these studies using standardized methods. We find consistent patterns characterizing disease-associated microbiome changes. Some diseases are associated with over 50 genera, while most show only 10–15 genus-level changes. Some diseases are marked by the presence of potentially pathogenic microbes, whereas others are characterized by a depletion of health-associated bacteria. Furthermore, we show that about half of genera associated with individual studies are bacteria that respond to more than one disease. Thus, many associations found in case–control studies are likely not disease-specific but rather part of a non-specific, shared response to health and disease.

Reported associations between the human microbiome and disease are often inconsistent. Here, Duvallet et al. perform a meta-analysis of 28 gut microbiome studies spanning ten diseases, and find associations that are likely not disease-specific but potentially part of a shared response to disease.

Schiff base complexes of copper and zinc as potential anti-colitic compounds

The design, synthesis and activity of polymodal compounds for the treatment of inflammatory bowel disease are reported. The compounds, being based on a metal-Schiff base motif, are designed to degrade during intestinal transit to release the bioactive components in the gut. The compounds have been developed sequential with the biomodal compounds combining copper or zinc with a salicylaldehyde adduct. These compounds were tested in a formalin induced colonic inflammation model in BK:A mice. From these studies a trimodal compound based on a zinc Schiff base analogue of sulfasalazine was designed. This was tested against a trinitrobenzenesulfonic acid (TNB) induced colitic model in Wistar rats. The use of two models allows us to test our compounds in both an acute and a chronic model. The trimodal compound reported is observed to provide anticolitic properties in the chronic TNB induced colitis model commensurate with that of SASP. However, the design of trimodal compound still has the capacity for further development. This the platform reported may offer a route into compounds which can markedly outperform the anti-colitic properties of SASP.

Organizing Pneumonia in a Patient with Quiescent Crohn’s Disease

A 64-year-old man with Crohn's disease (CD) was admitted to our hospital due to moderate risk of pneumonia while receiving scheduled adalimumab maintenance therapy. Symptoms remained virtually unchanged following administration of antibiotics. A final diagnosis of organizing pneumonia (OP) was made based on findings of intra-alveolar buds of granulation tissue and fibrous thickening of the alveolar walls on pathological examination and patchy consolidations and ground glass opacities on computed tomography. Immediate administration of prednisolone provided rapid, sustained improvement. Although a rare complication, OP is a pulmonary manifestation that requires attention in CD patients.

Organizing pneumonia presenting after ulcerative colitis remission

Ulcerative colitis (UC) is the most common form of inflammatory bowel disease worldwide, and extraintestinal manifestations (EIMs) involving various organs and systems occur in 10% to 30% of patients. Recently, although the pulmonary manifestation of UC is being increasingly recognized, these manifestations are described much less frequently than other EIMs. Furthermore, organizing pneumonia (OP) involving the lung parenchyma is a relatively uncommon pulmonary manifestation of UC, and to our knowledge, no case of OP after histologically confirmed UC remission has been previously reported in the English literature. Here, we present a case of OP after remission in an elderly female with a history of UC.

Erythrocyte deformability and oxidative stress in inflammatory bowel disease

BACKGROUND

Oxidative stress and reduced microvascular flow are important factors in the pathogenesis of inflammatory bowel disease (IBD). The increased oxidative stress reduces the erythrocyte deformability. However, in IBD, there are no studies in the literature which evaluate erythrocyte deformability.

AIMS

In our study, we investigated the effect of oxidative stress and erythrocyte deformability in IBD.

METHODS

Forty-three patients with active IBD, 48 patients with inactive IBD and 45 healthy controls were included. The erytrocyte deformability, malonyldialdehyde levels, glutation peroxidase and sulfhydryl levels were measured in peripheral venous blood samples.

RESULTS

Erytrocyte malonyldialdehyde levels in both active and inactive IBD were significantly increased compared with control groups. Plasma glutation peroxidase levels did not show statistically significant difference between all groups. The decreased plasma sulfhydryl levels in active IBD were statistically significant compared with both the inactive IBD and the control group, but plasma sulfhydryl levels in inactive IBD group did not show statistically significant differences when compared with the control group. Elongation index values in both active and inactive IBD increased significantly compared with the control group. Statistically significant correlations were not found between the elongation index and glutation peroxidase, malonyldialdehyde, sulfhydryl levels in all groups.

CONCLUSIONS

Our study is the first to evaluate the erythrocyte deformability in IBD. In our study, increased erytrocyte malonyldialdehyde levels and decreased plasma sulfhydryl levels manifested the role of oxidative stress in the pathogenesis of the disease. It is thought that the increased erythrocyte malonyldialdehyde values cause the reduction in erythrocyte deformability.

The effects of increased extracellular deformation, pressure, and integrin phosphorylation on fibroblast migration

Wound healing requires fibroblast migration. Increased pressure slows migration and ulcer healing. Pressure also induces beta1 integrin phosphorylation. We hypothesized that beta1 phosphorylation influences cell adhesion and migration. We compared the effects of increased pressure on the adhesion and motility of GD25 beta1-integrin null fibroblasts transfected with wild-type beta1A-integrin, S785A or TT788/9AA (phosphorylation-deficient), or T788D (constitutively phosphomimetic) mutants. GD25 beta1 null cells adhered less than wild type beta1A cells, suggesting adherence by non-integrin mechanisms. Preventing Ser-785 or Thr 788/789 phosphorylation reduced adhesion, suggesting that phosphorylation regulates adhesiveness. Substituting Asp for Thr788 stimulated adhesion on both substrates. Pressure decreased migration in all lines and on all matrixes, the most in wild type beta1A integrin cells and only slightly in beta1A TT788/9AA cells. In comparison, another physical force, repetitive deformation, increased migration in the beta1A integrin T788D, S785A, and wild type cells on fibronectin, and decreased migration on collagen. Deformation did not affect the migration of GD25 beta1-integrin null or TT788/9AA cells. Extracellular signal-regulated kinase (ERK) blockade neither altered basal migration nor prevented pressure inhibition, while the cellular deformation response on fibronectin was altered. beta1-Integrin phosphorylation regulates cellular adhesion and the deformation effects on motility. The pressure-induced motility response is independently regulated.

Supraphysiologic extracellular pressure inhibits intestinal epithelial wound healing independently of luminal nutrient flow

BACKGROUND

Luminal pressure may injure the gut mucosa in obstruction, ileus, or inflammatory bowel disease.

METHODS

We formed Roux-en-Y anastomoses in 19 mice, creating proximal and defunctionalized partially obstructed limbs and a distal limb to vary luminal pressure and flow. We induced mucosal ulcers by serosal acetic acid, and assessed proliferation (proliferating cell nuclear antigen) and ERK (immunoblotting). Parallel studies compared Caco-2 enterocyte migration and proliferation after pressure and/or ERK blockade.

RESULTS

At 3 days, anastomoses were probe-patent, proximal and distal limbs contained chyme, and defunctionalized limbs were empty. The proximal and defunctionalized limbs showed increased pressure and slower healing despite increased proliferation, ERK protein, and ERK activation. In vitro, pressure decreased Caco-2 migration across collagen or fibronectin, stimulated proliferation, and activated ERK. However, ERK blockade did not prevent pressure effects.

CONCLUSIONS

Luminal pressure during obstruction or ileus may impair mucosal healing independently of luminal flow despite increased mitosis and ERK activation.

Pulmonary abnormalities in inflammatory bowel disease

Extraintestinal manifestations of inflammatory bowel disease (IBD) is a common clinical problem affecting up to half of all IBD patients; pulmonary disease, however, ranks among less common extraintestinal manifestations of IBD. Pulmonary disease in patients with IBD is most frequently drug induced due to treatment with sulfasalazine or mesalamine leading to eosinophilic pneumonia and fibrosing alveolitis or due to treatment with methotrexate leading to pneumonitis. Recently, various opportunistic infections have been shown to be a further important cause of pulmonary abnormalities in those IBD patients who are treated with immunosuppressants such as anti TNF-α monoclonal antibodies, methotrexate, azathioprine or calcineurin antagonists. In not drug related pulmonary disease a wide spectrum of disease entities ranging from small and large airway dysfunction to obstructive and interstitial lung disorders exist. Patients with lung disorders and inflammatory bowel disease should be evaluated for drug-induced lung disease and opportunistic infections prior to considering pulmonary disease as an extraintestinal manifestation of inflammatory bowel disease.

The motogenic effects of cyclic mechanical strain on intestinal epithelial monolayer wound closure are matrix dependent

BACKGROUND & AIMS

Complex deformation during normal digestion due to peristalsis or villous motility may be trophic for the intestinal mucosa. Because tissue fibronectin is increased in inflammatory states that may accompany mucosal injury, we evaluated the effects of cyclic mechanical strain and fibronectin on intestinal epithelial monolayer wound closure in Caco-2 and IEC-6 intestinal epithelial cells.

METHODS

Wounds created in intestinal epithelial monolayers were subjected to cyclic deformation. Wound closure was assessed by morphometry using microscopic imaging. Cell signals were assessed by Western blot and confocal microscopy.

RESULTS

Mechanical strain stimulated wound closure on fibronectin but inhibited closure on collagen in Caco-2 and IEC-6 cells. The effect was independent of proliferation or cell spreading. Myosin light chain (MLC) and extracellular signal-regulated kinase (ERK) were phosphorylated in response to strain in confluent monolayers on both collagen and fibronectin. Blocking MLC or ERK phosphorylation inhibited the motogenic effect of strain on fibronectin. Although phosphorylated MLC was redistributed to the leading edge of migrating cells following 6 hours of strain on collagen and fibronectin, phosphorylated ERK was redistributed to the lamellipodial edge only on fibronectin.

CONCLUSIONS

Strain promotes intestinal epithelial wound closure by a pathway requiring ERK and MLC kinase. Fibronectin-dependent ERK redistribution in response to strain in confluent migrating cells may explain the matrix dependence of the motogenic effect. Repetitive deformation stimulates intestinal epithelial proliferation on a collagen substrate, but not fibronectin. Deformation may exert matrix-dependent effects on intestinal epithelial cells, promoting epithelial restitution in fibronectin-rich tissue and proliferation in fibronectin-poor mucosa.

Beneficial effects of N-acetylcysteine on acetic acid-induced colitis in rats

Ulcerative colitis is a chronic recurrent inflammatory bowel disease in which oxidative stress has been implicated. The aim of the present study was to evaluate possible protective effects of N-acetylcysteine against acetic acid-induced colitis in a rat model. Rats were administered intrarectal saline (control group) or acetic acid (colitis model group). Rats with acetic acid-induced colitis were treated by intraperitoneal or intrarectal administration of N-acetylcysteine (500 mg/kg) (treated group). Another series of rats were pre-treated by intraperitoneal or intrarectal administration of N-acetylcysteine, then administered intrarectal acetic acid (pre-treated group). The degree of tissue injuries was assessed by macroscopical and histopathological scores of the colonic mucosa. Malondialdehyde, myeloperoxidase, reduced glutathione, superoxide dismutase, and catalase levels were measured in tissue extracts of the dissected colon. Administration of N-acetylcysteine intraperitoneally or intrarectally ameliorated macroscopic score alterations produced by acetic acid in treated groups. In addition, microscopical improvement was observed in all N-acetylcysteine-treated rats compared to untreated animals with colitis. In the colonic tissues of the acetic acid-induced colitis, myeloperoxidase activity and malondialdehyde levels were elevated, while the reduced glutathione levels and superoxide dismutase and catalase activities were decreased. However, intraperitoneal or intrarectal treatment with N-acetylcysteine reversed these parameters, compared to the untreated colitis group. Notably, intrarectal administration of N-acetylcysteine elevated the reduced glutathione levels more markedly compared to the other treatment groups. Superoxide dismutase levels were increased in intraperitoneally or intrarectally N-acetylcysteine-treated groups significantly compared to the control, colitis and pre-treated groups. But there was no significant increase in catalase activity. In conclusion, N-acetylcysteine could be beneficial as a complementary agent in treatment of ulcerative colitis.

The role of esophagogastroduodenoscopy in the initial evaluation of childhood inflammatory bowel disease: a 7-year study

OBJECTIVES

To assess the role of esophagogastroduodenoscopy in the evaluation of children with suspected inflammatory bowel disease.

METHODS

All children with inflammatory bowel disease who underwent esophagogastroduodenoscopy during their initial evaluation at our institution during a 7-year period (December 1993 to November 2000) were included in the study.

RESULTS

The study included 115 patients: 81 with Crohn disease (mean age, 11.34 years; 42 males) and 34 with ulcerative colitis (mean age, 11.79 years; 20 males). Abnormal findings on esophagogastroduodenoscopy were noted in 64% of patients with Crohn disease and 50% of children with ulcerative colitis; histologic abnormalities were found in 81.6% and 70.6% of the patients, respectively. Granulomas were found in the upper gastrointestinal tracts of 23 of 81 patients (28.4%), with the most common site being the gastric mucosa. Nine of these 23 patients had granulomas solely in the upper gastrointestinal tract. Additional unsuspected pathology noted included: candidiasis, hiatal hernia, Helicobacter pylori infection, and giardiasis.

CONCLUSIONS

Endoscopic and histologic abnormalities were found in the upper gastrointestinal tracts of a significant number of children with inflammatory bowel disease. While the mechanism(s) underlying these abnormalities in patients with ulcerative colitis is unclear, the pathology can contribute to the patient's clinical condition. Pathology in the upper gastrointestinal tract should not exclude a diagnosis of ulcerative colitis. Granulomas, confirming the diagnosis of Crohn disease, were found in the upper gastrointestinal tracts of 28% of our patients with Crohn disease. In some cases, granulomas were found solely in the upper gastrointestinal tracts. Based on our data, esophagogastroduodenoscopy with biopsy should be performed in all pediatric patients with suspected inflammatory bowel disease.

Oxidative stress and antioxidant capacity in patients with inflammatory bowel disease

OBJECTIVES

In this study we aimed to determine the levels of Glutathione peroxidase (GSH-Px) and Malondialdehyde (MDA) in patients with inflammatory bowel disease (IBD) to investigate their contribution to tissue injury in inflammatory bowel disease.

DESIGN AND METHODS

Forty-seven GSH-Px patients (35 with ulcerative colitis and 12 with Crohn's disease) and 30 healthy controls were included in the study. Their plasma and MDA levels were compared using nonparametric statistical methods.

RESULTS

Plasma GSH-Px levels of the patients group were significantly higher than the control group (p < 0.001). There was no significant difference between patients and controls in view of plasma levels of MDA.

CONCLUSIONS

High levels of GSH-Px, which is response against oxidative stress, indicates the increase of free radicals in IBD, while normal plasma MDA levels suggest the clearance of free radicals without leading to lipid peroxidation. Our result reveals that there is an existing antioxidant capacity despite oxidative stress in patients with IBD.

Clinical aspects and pathophysiology of inflammatory bowel disease

The chronic inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis, are recognized as important causes of gastrointestinal disease in children and adults. In this review we delineate the clinical manifestations and diagnostic features of IBD. In addition, we summarize important recent advances in our understanding of the immune mediators of intestinal inflammation. This information has led to new therapeutic approaches in IBD. Further, we discuss the considerable data that point to the significance of genetic factors in the development of IBD and the genetic loci which have been implicated through genome-wide searches. The commensal bacterial flora also appears to be a critical element, particularly in regards to Crohn's disease, although the precise role of the bacteria in the disease manifestations remains unclear. Current investigations promise to yield fresh insights in these areas.

OPC-compounds prevent oxidant-induced carbonylation and depolymerization of the F-actin cytoskeleton and intestinal barrier hyperpermeability

Rebamipide (OPC-12759), a quinolone derivative, and OPC-6535, a thiazol-carboxylic acid derivative, are compounds with ability to protect gastrointestinal (GI) mucosal integrity against reactive oxygen metabolites (ROM). The underlying mechanism of OPC-mediated protection remains poorly understood. It is now established that ROM can injure the mucosa by disruption of the cytoskeletal network, a key component of mucosal barrier integrity. We, therefore, investigated whether OPC compounds prevent the oxidation, disassembly, and instability of the cytoskeletal protein actin and, in turn, protect intestinal barrier function against ROM. Human intestinal (Caco-2) cell monolayers were pretreated with OPC (-12759 or -6535) prior to incubation with ROM (H2O2) or HOCl). Effects on cell integrity (ethidium homodimer-1), epithelial barrier function (fluorescein sulfonic acid clearance), and actin cytoskeletal integrity (high-resolution laser confocal) were then determined. Cells were also processed for quantitative immunoblotting of G- and F-actin to measure oxidation (carbonylation) and disassembly of actin. In monolayers exposed to ROM, preincubation with OPC compounds prevented actin oxidation, decreased depolymerized G-actin, and enhanced the stable F-actin. Concomitantly, OPC agents abolished both actin cytoskeletal disruption and monolayer barrier dysfunction. Data suggest for the first time that OPC drugs prevent oxidation of actin and lead to the protection of actin cytoskeleton and intestinal barrier integrity against oxidant insult. Accordingly, these compounds may be used as novel therapeutic agents for the treatment of a variety of oxidative inflammatory intestinal disorders with an abnormal mucosal barrier such as inflammatory bowel disease.

Microaggregate of immunostained macrophages in noninflamed gastroduodenal mucosa: a new useful histological marker for differentiating Crohn's colitis from ulcerative colitis

OBJECTIVE

In 10% of cases it may be difficult to differentiate Crohn's colitis from ulcerative colitis. Distinguishing the two conditions is important because they are distinct entities with different therapeutic implications. Noncaseating granulomas are usually considered diagnostic of Crohn's disease. We previously reported that the presence of a microaggregate of immunostained macrophages within the noninflamed gastroduodenal mucosa was a characteristic finding of Crohn's disease. The aim of this study was to determine whether a microaggregate of immunostained macrophages can be a reliable marker for differentiating Crohn's colitis from ulcerative colitis.

METHODS

We investigated the presence of microaggregates of immunostained macrophages and epithelioid cell granulomas in biopsy specimens taken from the noninflamed gastroduodenal mucosa of 22 known Crohn's colitis patients and 23 established ulcerative colitis patients. The incidence of microaggregates and granulomas was compared between these two groups.

RESULTS

Microaggregates and granulomas were detected only in the Crohn's colitis patients. In addition, the presence of microaggregates was more frequent than that of granulomas in Crohn's colitis patients (54.5% and 18.2%, respectively, 95% confidence interval for the difference: 10.0-62.7%).

CONCLUSION

Detecting a microaggregate of immunostained macrophages in a biopsy specimen taken from noninflamed gastroduodenal mucosa seems to be a useful method for differentiating Crohn's colitis from ulcerative colitis.

HLA-DRB and HLA-DQB loci in the genetic susceptibility to develop glaucoma in Mexicans

PURPOSE

Glaucoma is a clinically heterogeneous disease with a pathophysiology that may include genetic susceptibility, possibly associated with an immunologic disorder. The aim of this study was to determine whether the DNA polymorphisms located in the HLA-DRB1 and HLA-DQB1 genes show a specific association pattern in Mexican mestizo patients with primary open-angle glaucoma.

METHODS

This was a cross-sectional, case-control, multicenter study. We analyzed the HLA-DRB1 and DQB1 loci of 81 Mexican mestizo nonrelated patients with primary open-angle glaucoma and 98 healthy ethnic matched control subjects. Patients were diagnosed clinically and by visual fields examination. HLA typing was performed by PCR-SSO reverse dot blot.

RESULTS

We documented increased frequencies of HLA-DRB1*0301, DRB1*1101, DRB1*0701, DRB1*1402, DQB1*0302, and DQB1*0301; however, none of them were significantly different from normal control subjects. Haplotype analysis showed that the HLA-DRB1*0407-DQB1*0302 haplotype is significantly increased in patients compared with control subjects (P = .0001).

CONCLUSIONS

The haplotype HLA-DRB1*0407-DQB1*0302 is common among Mexican mestizo (haplotype frequency = 0.102), and it was increased in our patients (haplotype frequency = 0.259, P = .0001). This may reflect an independent association of this haplotype with the disease as the result of linkage disequilibrium or the influence of a neighboring gene. The pathophysiology of this illness is uncertain, and further studies are needed regarding the genetic susceptibility to develop primary open-angle glaucoma.

Colon-specific delivery of R68070, a new thromboxane synthase inhibitor, using chitosan capsules: therapeutic effects against 2,4,6-trinitrobenzene sulfonic acid-induced ulcerative colitis in rats

The objective of this study was to estimate the therapeutic effects of R68070, a new thromboxane synthase inhibitor, on 2,4,6-trinitrobenzenesulfonic acid sodium salt (TNBS)-induced ulcerative colitis in rats. We also examined the acceleration of the healing effect of R68070 with chitosan capsules to achieve its colon-specific delivery. The colonic injury and inflammation were assessed by measuring the myeloperoxidase (MPO) activities, colon wet weight/body weight (C/B) ratio and the damage score, respectively. These markers were decreased by the oral administration of R68070 with chitosan capsules and carboxymethyl-cellulose (CMC) suspension. The therapeutic effects of R68070 against ulcerative colitis were observed in both dosage forms in a dose dependent manner. In addition, its therapeutic effects were increased by the use of chitosan capsules, compared with CMC suspension. These results suggest that chitosan capsule might be a very useful dosage form for the colon-specific delivery of R68070 as an anti-inflammatory drug and for the therapy of ulcerative colitis.

Breath alkanes determination in ulcerative colitis and Crohn's disease

PURPOSE

By considering the pathophysiologic basis of inflammatory bowel diseases, a role for excessive lipid peroxidation caused by oxygen free radical compounds has been proposed repeatedly. However, to date only a few studies are available on this topic in human beings. This study was designed to assess breath alkanes in a group of patients with active inflammatory bowel disease by a technique that clearly distinguishes pentane from isoprene, to prevent overestimation of values as in previous studies.

PATIENTS

Twenty patients with a diagnosis of active inflammatory bowel disease (10 with Crohn's disease and 10 with ulcerative colitis) were studied. Extension of the disease was similar between patient groups, and all were treated with equivalent doses of steroids and salicylates.

METHODS

Breath alkanes determination was performed by a standard procedure involving a gas chromatography column able to separate pentane from isoprene.

RESULTS

Overall, significant differences between patients with inflammatory bowel diseases and controls were found for ethane, propane, and pentane, but not for butane and isoprene. Isoprene was clearly distinguished from pentane, demonstrating that the significant elevation of pentane levels in patients with inflammatory bowel diseases is a real phenomenon and not an artifact caused by coelution with isoprene.

CONCLUSIONS

An excess of lipid peroxidation is probably an important pathogenetic factor in inflammatory bowel diseases, and this may be assessed through a noninvasive method. Because this method previously also has been shown to be able to evaluate disease activity, it could be a useful tool for studying patients with inflammatory bowel diseases.

The concept of type-1 and type-2 helper T cells and their cytokines in humans

In both mice and humans, functionally distinct helper T (Th)-cell subsets, known as Th1 and Th2 cells, are characterized by the patterns of cytokines they produce. These two polarized forms of the specific cellular immune response provide a useful model for explaining not only the different types of protection, but also the pathogenic mechanisms of several immunopathological disorders. The development of polarized Th1 or Th2 responses depends on either environmental factors, including dose of antigen, nature of immunogen and cytokines (IL-12 and interferons or IL-4) at the time of antigen presentation, or other undefined factors in the individual genetic background, mainly at level of the so-called "natural immunity". Th1-dominated responses are potentially effective in eradicating infectious agents, including those hidden within the host cells. When the Th1 response is poorly effective or exhaustively prolonged, it may result in host damage. In contrast, Th2 responses are apparently insufficient to protect against the majority of infectious agents, but can provide some protection against parasites. Th2 cells are able to make unpleasant the life of parasites in the host and tend to limit potentially harmful Th1-mediated responses. Thus, Th2 cells may be regarded as a part of down regulatory (or suppressor) mechanism for exaggerated and/ or inappropriate Th1 responses. The Th1/Th2 paradigm applied to the study of chronic inflammatory disorders or autoimmune diseases allowed to understand that a number of diseases are mediated by Th1 cells, the two clearest examples being multiple sclerosis and thyroid autoimmunity. In other disorders, Th1/Th2 polarization is less prominent, or rather Th2 responses tend to predominate, such as in systemic lupus erythematosus, progressive systemic sclerosis or allergic diseases. It is of note that in experimental models in animals, a number of diseases can be prevented by switching immune responses from Th1 to Th2 or from Th2 to Th1. Moreover, the Th1/Th2 concept suggests that modulation of the relative contribution of Th1- or Th2-type cytokines makes possible to regulate the balance between protection and immunopathology, as well as the development and/or the severity of some immunologic disorders.

Regulation of neutrophils in ulcerative colitis by colonic factors: a possible mechanism of neutrophil activation and tissue damage

The mucosal injury of active ulcerative colitis (UC) could involve enhanced migration and activation of neutrophils (PMNs). Because, in vitro, PMNs from patients with UC appear normal and are not therefore a likely cause for the enhancements, we hypothesized an abnormal colonic milieu. We previously found that factors in the UC colonic milieu markedly increase production of reactive oxygen species (ROS) by control PMNs. We now hypothesize that these factors also regulate PMN surface integrins, that regulation of UC PMNs is different than that of control PMNs, and that the integrin regulation is consistent with the ROS regulation. Using rectal dialysis, we sampled the colonic milieu in patients with active UC, in patients with inactive UC, and in control subjects. We monitored a key PMN adhesion molecule, CD11b. When control PMNs were tested, active UC rectal dialysate was almost as effective (+115%) as N-formyl-methionyl-leucyl-phenylalanine (+132%) in up-regulating CD11b. When inactive UC PMNs were tested, baseline CD11b was 50% higher than that for control PMNs. In contrast, rectal dialysates failed to up-regulate CD11b of inactive UC PMNs and in fact down-regulated CD11b. Preincubating control PMNs with UC rectal dialysates converted their CD11b response to PMN activators from up-regulation to down-regulation, mimicking inactive UC PMNs. Changes in intracellular calcium levels paralleled these changes in CD11b. Rectal dialysate-induced changes in both CD11b and calcium paralleled our previous findings on rectal dialysate-induced changes in ROS production. Thus the net overall effect of factors in the colonic milieu is a consistent and predictable regulation of PMN function--proinflammatory in UC, anti-inflammatory in control subjects. These factors may be a critical part of the pathophysiology of UC.

Selective depletion of neutrophils by a monoclonal antibody, RP-3, suppresses dextran sulphate sodium-induced colitis in rats

Administration of dextran sulphate sodium to animals induces acute colitis characterized by infiltration of large numbers of neutrophils into the colonic mucosa, which histologically resembles human active ulcerative colitis. It has been reported that neutrophils and the reactive oxygen metabolites produced by them are involved in the progress of ulcerative colitis. This study was intended to clarify their roles by using this animal model. First, possible sources and species of reactive oxygen metabolites were determined using luminol-dependent chemiluminescence with addition of enzyme inhibitors and reactive oxygen metabolite scavengers. Next, to examine whether neutrophils and hypochlorous acid derived from them contribute to tissue injury, we administered RP-3, a monoclonal antibody capable of selectively depleting neutrophils, and taurine, a hypochlorous acid scavenger, to rats treated with dextran sulphate sodium. Addition of azide, taurine, catalase, superoxide dismutase and dimethyl sulphoxide into colonic mucosal scrapings significantly inhibited chemiluminescence production, but allopurinol and indomethacin had no effects. These results suggest that excessive hypochlorous acid, hydrogen peroxide, superoxide anion and hydroxyl radical are generated by the inflamed colonic mucosa. Intraperitoneal injections of RP-3 significantly suppressed bleeding, tissue myeloperoxidase activity, chemiluminescence production and erosion formation. On the other hand, administration of taurine tended to inhibit bleeding and erosion formation to some extent, although it could not significantly suppress them. These data suggest that neutrophils play an important role in the development of this colitis and that hypochlorous acid might be one of the causes of tissue injury induced by neutrophils.

Universal skew of T cell receptor (TCR) V beta usage for Crohn's disease (CrD)

It would be of clear interest and importance to identify T cell populations which correlate with the initiation of some T cell-mediated diseases; however, it is difficult to observe the initial response of T cells in these diseases because of modification due to immunosuppressive treatment. We investigated T cell receptor (TCR) V beta usage in both affected and unaffected mucosa from 16 patients with active Crohn's disease (CrD), undergoing nutritional therapy without any immunomodulatory medications. Semiquantitative reverse transcriptase-polymerase chain reaction showed increased expression of V beta 12 and 13 in the entire mucosa of CrD but not in the controls. This was confirmed by introducing a random cloning method. Such skewing was observed primarily in CD4+ lamina propria lymphocytes. DNA sequence analysis demonstrated a striking clonal expansion of V beta 12 T cells, but the dominant clones were not identical in the patients. These findings suggest the importance of superantigen as well as specific T cell response in the pathogenesis of CrD.

Colonoscopy or sigmoidoscopy as the initial evaluation of pediatric patients with colitis: a survey of physician behavior and a cost analysis

BACKGROUND

Pediatric patients presenting with colitis, suggestive of inflammatory bowel disease, undergo evaluation with either flexible sigmoidoscopy or colonoscopy. Our objectives were to assess current practice behavior in the evaluation of pediatric patients with colitis and to determine whether flexible sigmoidoscopy or colonoscopy was more cost-effective as the initial evaluation.

METHODS

Practice behavior and procedure charges were assessed using a nationwide survey, and costs for diagnostic strategies were compared using a decision analysis program.

RESULTS

The vast majority of survey respondents would proceed with colonoscopy if colitis suggestive of Crohn's disease was noted in the rectosigmoid area (81%) or if ulcerative colitis extended proximal to the rectosigmoid area (70%). If colonoscopy would follow if flexible sigmoidoscopy suggested either ulcerative colitis or Crohn's disease (67%), then colonoscopy would result in a savings of 23%. If the evaluation was predetermined to be limited to flexible sigmoidoscopy (16%), then flexible sigmoidoscopy was the cost-effective strategy with savings of 29%. If colonoscopy would follow flexible sigmoidoscopy for Crohn's colitis only (13%), there was no clear cost advantage.

CONCLUSIONS

The most cost-effective strategy depends on the physician's need to know the disease location. Our survey results indicate that most physicians chose to establish the extent of disease in both ulcerative colitis and in Crohn's disease; thus initial colonoscopy would be the more cost-effective strategy. When knowledge of disease distribution is not essential for patient care, flexible sigmoidoscopy can lead to substantial cost savings.

Bacterial persistence and expression of disease

A considerable body of experimental and clinical evidence supports the concept that difficult-to-culture and dormant bacteria are involved in latency of infection and that these persistent bacteria may be pathogenic. This review includes details on the diverse forms and functions of individual bacteria and attempts to make this information relevant to the care of patients. A series of experimental studies involving host-bacterium interactions illustrates the probability that most bacteria exposed to a deleterious host environment can assume a form quite different from that of a free-living bacterium. A hypothesis is offered for a kind of reproductive cycle of morphologically aberrant bacteria as a means to relate their diverse tissue forms to each other. Data on the basic biology of persistent bacteria are correlated with expression of disease and particularly the mechanisms of both latency and chronicity that typify certain infections. For example, in certain streptococcal and nocardial infections, it has been clearly established that wall-defective forms can be induced in a suitable host. These organisms can survive and persist in a latent state within the host, and they can cause pathologic responses compatible with disease. A series of cases illustrating idiopathic conditions in which cryptic bacteria have been implicated in the expression of disease is presented. These conditions include nephritis, rheumatic fever, aphthous stomatitis, idiopathic hematuria, Crohn's disease, and mycobacterial infections. By utilizing PCR, previously nonculturable bacilli have been identified in patients with Whipple's disease and bacillary angiomatosis. Koch's postulates may have to be redefined in terms of molecular data when dormant and nonculturable bacteria are implicated as causative agents of mysterious diseases.

Functional studies of in vitro rat distal colon before and after restitution

BACKGROUND

Epithelial injury occurs in many acute and chronic diseases of the colon and from simple mechanical and chemical injury in the normal colon. Because epithelial repair is so important, we developed a highly reproducible, entirely in vitro model of restitution in rat distal colon.

METHODS

The muscosal surface of colon mounted in Ussing chambers was exposed to 1.5 mol/L NaCl (hypertonic saline, HS) for 10 minutes. Transepithelial potential difference, electrical resistance, and short-circuit current were used to measure return of electrophysiologic characteristics of the tissue during recovery from injury. Recovery of the barrier to transepithelial movement of large molecules was assessed by measuring mannitol and inulin permeability. Na+ and Cl- absorption and forskolin-induced Cl- secretion were used as indicators of functional recovery of the colonic mucosa after HS injury. Morphologic evaluation of tissues was performed by light microscopy and transmission electron microscopy.

RESULTS

HS treatment caused marked increases in mannitol and inulin permeability together with exfoliation of colonocytes from the surface and upper crypts, leaving long stretches of denuded basal lamina. Epithelial continuity was morphologically reestablished in 30 to 60 minutes, concomitant with return of permeability to control levels. Potential difference, electrical resistance, and short-circuit current decreased with injury and then gradually recovered, although not to preinjury level. Net Na+ and Cl- absorptions, present in undamaged tissues at approximately equivalent rates, decreased after restitution. Forskolin-stimulated Cl- secretion, present before injury, was abolished after restitution.

CONCLUSIONS

These studies describe a highly reproducible in vitro model of injury and restitution of a fully organized epithelium of rat distal colon. Although morphologic continuity and barrier properties recover after extensive superficial mucosal injury, the surface is repopulated by cells displaying transport properties and ultrastructural characteristics distinct from the surface epithelium of undamaged tissues.

The role of cigarettes and nicotine in the onset and treatment of ulcerative colitis

Epidemiological evidence suggests that ulcerative colitis is a disease of nonsmokers, while Crohn's disease is a disease of smokers. The relative risk of developing ulcerative colitis is not only greater in nonsmokers, in addition there appears to be a rebound effect in smokers who quit, with the heaviest (ex-)smokers increasing their relative risk of the disease the most. This factor poses an ethical dilemma for health professionals giving advice on stopping smoking, which may thus have a serious detrimental effect on the health of some patients. Nicotine is believed to be the pharmacological ingredient of tobacco that is responsible for this beneficial effect and several clinical trials using nicotine have demonstrated it to be an effective therapeutic agent in the treatment of ulcerative colitis. Although the aetiology of ulcerative colitis is unclear, current research using nicotine-based products has produced some interesting clues, together with the possibility of some form of therapeutic treatment based on nicotine administration.

Increased oxidative stress and decreased antioxidant defenses in mucosa of inflammatory bowel disease

Inflammatory bowel disease (IBD) is characterized by chronic intestinal inflammation whose cellular components are capable of oxidative respiratory bursts that may result in tissue injury. Mucosal biopsies were analyzed for protein carbonyl content (POPs), DNA oxidation products [8-hydroxy-2'-deoxyguanosine (8-OHdG)], reactive oxygen intermediates (ROIs), trace metals (copper, zinc, and iron) and superoxide dismutase (Cu-Zn SOD). In Crohn's disease biopsies, there was an increase in ROIs, POPs, 8-OHdG, and iron, while decreased copper and Cu-Zn SOD activity were found in inflamed tissues compared to controls. For ulcerative colitis, there was an increase in ROIs, POPs, and iron in inflamed tissue compared to controls, while decreased zinc and copper were observed. An imbalance in the formation of reactive oxygen species and antioxidant micronutrients may be important in the pathogenesis and/or perpetuation of the tissue injury in IBD and may provide a rationale for therapeutic modulation with antioxidants.

The effect of a selective 5-lipoxygenase inhibitor, zileuton, on tissue damage in acute colonic inflammation in rats

Though the mechanism of tissue damage induced by colonic inflammation in ulcerative colitis is unknown, it has been established that the inflammatory mediator and potent neutrophil (PMN) chemotaxin, leukotriene B4(LTB4), is present in elevated amounts in the inflamed mucosa. The unique role of 5-lipoxygenase in the production of leukotrienes has made it a target for inhibition. This study used a rat model of acute colonic inflammation induced by a single IP injection of Mitomycin-C to test the efficacy of a specific and potent 5-lipoxygenase inhibitor zileuton in the treatment of colonic inflammation. We hypothesized that after inducing colitis in rats with mitomycin-C, the administration of oral zileuton would inhibit leukotriene production, thus preventing PMN infiltration and subsequent tissue damage. Zileuton decreased colonic tissue damage as measured by Histological score. However, zileuton did not significantly decrease neutrophil infiltration measured by mucosal PMN or myeloperoxidase (MPO) levels. Although zileuton was successful in significantly decreasing the frequency of severe colitis in our model, the fact that the decrease in PMN count and MPO level was not statistically significant suggests that another mechanism may be involved in its anti-inflammatory effect.

A stable nitroxide radical effectively decreases mucosal damage in experimental colitis

TEMPOL, a cyclic nitroxide stable radical blocks biological damage by breaking chain reactions through termination reaction with free radicals, and by inhibiting the catalytic effect of transition metals. This study tested its protective effect on two models of experimental colitis as free radicals play an important part in their pathogenesis. TEMPOL was given intragastrically immediately after induction of colitis with acetic acid or trinitrobenzene sulphonic acid (TNB) and mucosal damage was assessed one, three, or seven days later. Cellular partition of TEMPOL was determined by electron paramagnetic resonance spectroscopy. In vitro experiments showed that TEMPOL immediately penetrates colonic mucosa and, following its intragastric administration, it persists in both gastric and colonic mucosa for several hours. Intragastric administration of TEMPOL, 0.5 g/kg/bw, immediately after intracaecal administration of 5% acetic acid significantly decreased mucosal lesion area, myeloperoxidase activity, and leukotriene B4 and C4 generation when assessed 24 hours after damage induction. Intragastric administration of TEMPOL, 0.5 g/kg/bw, immediately after intracolonic administration of 30 mg TNB in 0.25 ml 50% ethanol, and once daily thereafter, significantly decreased mucosal lesion area assessed after one, three, and seven days, having no effect on LTC4 generation and affecting colonic weight, myeloperoxidase activity, and LTB4 generation only sporadically. In conclusion, TNB and acetic acid induced colitis can be pharmacologically manipulated by TEMPOL. TEMPOL may be beneficial in the treatment or prevention of inflammatory bowel disease.

Induction and immunolocalization of manganese superoxide dismutase in acute acetic acid-induced colitis in the rat

BACKGROUND & AIMS

Oxygen radicals and reactive oxygen species play an important role in inflammatory episodes in the bowel. Nonetheless, little is known about the regulation of colonic superoxide dismutases and key antioxidant enzymes with cytoprotective and radical detoxifying properties. The aim of this study was to examine the regulation of manganese superoxide dismutase (SOD) in acute acetic acid-induced colitis.

METHODS

Colitis was induced in adult rats by the rectal administration of 5% acetic acid. Total RNA and protein were isolated from the inflamed colon from 1 to 24 hours after the induction of colitis. MnSOD messenger RNA and protein levels were evaluated by Northern and Western analyses, respectively. MnSOD protein was localized in cross sections of the colon by immunocytochemistry.

RESULTS

MnSOD messenger RNA levels showed a rapid 14-96-fold induction in response to acetic acid administration. Western analysis showed a 22-49-fold induction in MnSOD protein levels. Immunocytochemistry showed induction of MnSOD protein, specifically in smooth muscle cells, epithelial cells at the base of the glands, and myenteric plexus neurons.

CONCLUSIONS

MnSOD messenger RNA and protein levels are rapidly induced following the inflammatory insult, implicating a role for MnSOD in the acute phase of colonic inflammation. We suggest that induction of MnSOD in specific cell types may have a cytoprotective function.