Cytokine mRNA expression in intestine from normal and inflammatory bowel disease patients

Dual Biologic Therapy in an Adolescent With Camurati-Engelmann Disease and Crohn Disease

Camurati-Engelmann disease (CED) is a rare disorder caused by activating mutations in the TGF-β1 gene and characterized by hyperostosis of long bones and bone dysplasia. We describe a case of an adolescent with CED and moderate-severe Crohn Disease (CD). Infliximab improved gastrointestinal symptoms but was associated with worsening CED-associated bone pain. Clinical remission was successfully achieved with dual biologic therapy that included vedolizumab and ustekinumab. Possible reasons for this patient's clinical response are advanced and include speculation about the complex role of TGF-β1 signaling in the etiology of both CED and CD.

A novel role of pirfenidone in attenuation acetic acid induced ulcerative colitis by modulation of TGF-β1 / JNK1 pathway

Colon diseases are a major health burden, particularly ulcerative colitis, in both men and women worldwide. Environmental and genetic factors in various colonic pathologies influence the onset and outcome of diseases. As the evidence from recent research is considered, the importance of inflammation in the onset, progression, and outcome is gaining more traction. The goal of this study was to see if pirfenidone could treat ulcerative colitis (UC) and if so, what mechanisms were involved. By intracolonic instillation [2 ml, 3 percent v/v acetic acid (AA)], ulcerative colitis was induced. Pirfenidone was administered to rats in different experimental groups (125 or 250 and 500 mg/kg, orally) for two weeks. Compared to normal group, the AA group showed an increase in colon weight, length, body weight, clinical evaluation, and macroscopic scoring of UC, serum lactate dehydrogenase, C-reactive protein, malondialdehyde, while decreasing serum total antioxidant capacity. Significant increases in colon Jun N terminal kinase1 (JNK1), transforming growth factor-beta (TGF-β1), interleukin 1 beta (IL1β), and Caspase-3 content. Furthermore, immunohistochemical staining revealed increased nuclear factor kappa B (NF-κB) expression along with histopathological changes. Pirfenidone inhibited inflammatory biomarkers release and restored oxidants/antioxidants hemostasis. In a dose-dependent manner, pirfenidone treatment showed a significantly decrease in all of these parameters. In addition, pirfenidone has significantly preserved the histopathological architecture of tissues. Current data demonstrate that Pirfenidone protects against AA-induced UC by modulating the TGF-β1/JNK1 and Caspase-3 pathways. Pirfenidone's antioxidant, anti-inflammatory, and anti-apoptotic properties are thought to be responsible for its therapeutic benefit.

Colonic mucosal and cytobrush sample cytokine mRNA expression in canine inflammatory bowel disease and their correlation with disease activity, endoscopic and histopathologic score

Canine inflammatory bowel disease (IBD) is a group of chronic gastrointestinal disorders, the pathogenesis of which remains elusive, but it possibly involves the interaction of the intestinal immune system with luminal microbiota and food-derived antigens. Mucosal cytokines profiles in canine IBD have been investigated mainly in small intestinal disease, while data on cytokine profiles in large intestinal IBD are limited. The objective of this study was to measure colonic mucosal and cytobrush sample messenger (m)RNA expression of interleukin (IL)-1β, IL-2, IL-12p40, IL-23p19, tumor necrosis factor-alpha (TNF-α) and chemokine C-C motif ligand (CCL28) in dogs with IBD and healthy controls using quantitative real-time polymerase chain reaction (PCR), and assess their correlation with clinical disease activity, endoscopic and histopathologic score. Dogs with IBD had a significantly increased mRNA expression of IL-1β, IL-23p19 and CCL28 in the colonic mucosa, compared to healthy controls. None of the selected cytokines had significantly different mRNA expression in the colonic cytobrush samples between the two groups or between the colonic mucosa and cytobrush samples of dogs with IBD. Finally, there was a statistically significant correlation of clinical disease activity with endoscopic activity score and fibrosis and atrophy of the colonic mucosa in dogs with large intestinal IBD. IL-1β, IL-23p19 and CCL28 could play a role in the pathogenesis of canine large intestinal IBD. Colonic cytokine expression does not correlate with clinical disease activity and/or endoscopic score. However, clinical signs reflect the severity of endoscopic lesions.

Physical Activity Shapes the Intestinal Microbiome and Immunity of Healthy Mice but Has No Protective Effects against Colitis in MUC2-/- Mice

Perturbation in the gut microbial ecosystem has been associated with various diseases, including inflammatory bowel disease. Habitual physical activity, through its ability to modulate the gut microbiome, has recently been shown to prophylactically protect against chemically induced models of murine colitis. Here, we (i) confirm previous reports that physical activity has limited but significant effects on the gut microbiome of mice and (ii) show that such changes are associated with anti-inflammatory states in the gut, such as increased production of beneficial short-chain fatty acids and lower levels of proinflammatory immune markers implicated in human colitis; however, we also show that (iii) these physical activity-derived benefits are completely lost in the absence of a healthy intestinal mucus layer, a hallmark phenotype of human colitis.

The interactions among humans, their environment, and the trillions of microbes residing within the human intestinal tract form a tripartite relationship that is fundamental to the overall health of the host. Disruptions in the delicate balance between the intestinal microbiota and host immunity are implicated in various chronic diseases, including inflammatory bowel disease (IBD). There is no known cure for IBD; therefore, novel therapeutics targeting prevention and symptom management are of great interest. Recently, physical activity in healthy mice was shown to be protective against chemically induced colitis; however, the benefits of physical activity during or following disease onset are not known. In this study, we examine whether voluntary wheel running is protective against primary disease symptoms in a mucin 2-deficient (Muc2^−/−) lifelong model of murine colitis. We show that 6 weeks of wheel running in healthy C57BL/6 mice leads to distinct changes in fecal bacteriome, increased butyrate production, and modulation in colonic gene expression of various cytokines, suggesting an overall primed anti-inflammatory state. However, these physical activity-derived benefits are not present in Muc2^−/− mice harboring a dysfunctional mucosal layer from birth, ultimately showing no improvements in clinical signs. We extrapolate from our findings that while physical activity in healthy individuals may be an important preventative measure against IBD, for those with a compromised intestinal mucosa, a commonality in IBD patients, these benefits are lost.

IMPORTANCE Perturbation in the gut microbial ecosystem has been associated with various diseases, including inflammatory bowel disease. Habitual physical activity, through its ability to modulate the gut microbiome, has recently been shown to prophylactically protect against chemically induced models of murine colitis. Here, we (i) confirm previous reports that physical activity has limited but significant effects on the gut microbiome of mice and (ii) show that such changes are associated with anti-inflammatory states in the gut, such as increased production of beneficial short-chain fatty acids and lower levels of proinflammatory immune markers implicated in human colitis; however, we also show that (iii) these physical activity-derived benefits are completely lost in the absence of a healthy intestinal mucus layer, a hallmark phenotype of human colitis.

Role of regenerating islet-derived proteins in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an inflammatory disorder of the gastrointestinal tract that affects millions of patients worldwide. It has a complex and multifactorial etiology leading to excessive exposure of intestinal epithelium to microbial antigens, inappropriate activation of the immune system and ultimately to the damage of intestinal tissues. Although numerous efforts have been made to improve the disease management, IBD remains persistently recurring and beyond cure. This is due largely to the gaps in our understanding of the pathogenesis of IBD that hamper the development of timely diagnoses and effective treatment. However, some recent discoveries, including the beneficial effects of interleukin-22 (IL-22) on the inflamed intestine, have shed light on a self-protective mechanism in IBD. Regenerating islet-derived (REG/Reg) proteins are small secretory proteins which function as IL-22's downstream effectors. Mounting studies have demonstrated that IBD patients have significantly increased REG expressions in the injured intestine, but with undefined mechanisms and roles. The reported functions of REG/Reg proteins in intestinal homeostasis, such as those of antibacterial, anti-inflammatory and tissue repair, lead us to discuss their potential mechanisms and clinical relevance in IBD in order to advance IBD research and management.

Synthesis, activity and mechanism of alkoxy-, carbamato-, sulfonamido-, thioureido-, and ureido-derivatives of 2,4,5-trimethylpyridin-3-ol against inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic immuno-inflammation in gastrointestinal tract. We have evaluated the activity of the compounds to inhibit the adhesion of monocytes to colon epithelial cells is triggered by a pro-inflammatory cytokine, tumour necrosis factor (TNF)-α. The in vitro activity of the compounds, 13b (an ureido-derivative), 14c, 14j, 14k, 14n (thioureido-), 18c and 18d (sulfonamido-), was in correlation with in vivo anti-colitis activity revealed as significant recovery in body- and colon-weights and colon myeloperoxidase level, a biochemical marker of inflammation reflecting neutrophil infiltration. In vivo, TNBS-induced changes in the expression of inflammatory cytokines (TNF-α, IL-6, IL-1β, IL-10, and TGF-β), NLRP3 inflammasome components (NLRP-3, Caspase-1, and IL-18), and epithelial junction molecules (E-cadherin, claudin2/3, and ZO-1) were blocked and recovered by oral administration of the compounds (1 mg/kg). Compound 14n which showed the best efficacy can be a promising lead for orally available therapeutics for pathology of IBD.

Curcumin and Intestinal Inflammatory Diseases: Molecular Mechanisms of Protection

Intestinal inflammatory diseases, such as Crohn’s disease, ulcerative colitis, and necrotizing enterocolitis, are becoming increasingly prevalent. While knowledge of the pathogenesis of these related diseases is currently incomplete, each of these conditions is thought to involve a dysfunctional, or overstated, host immunological response to both bacteria and dietary antigens, resulting in unchecked intestinal inflammation and, often, alterations in the intestinal microbiome. This inflammation can result in an impaired intestinal barrier allowing for bacterial translocation, potentially resulting in systemic inflammation and, in severe cases, sepsis. Chronic inflammation of this nature, in the case of inflammatory bowel disease, can even spur cancer growth in the longer-term. Recent research has indicated certain natural products with anti-inflammatory properties, such as curcumin, can help tame the inflammation involved in intestinal inflammatory diseases, thus improving intestinal barrier function, and potentially, clinical outcomes. In this review, we explore the potential therapeutic properties of curcumin on intestinal inflammatory diseases, including its antimicrobial and immunomodulatory properties, as well as its potential to alter the intestinal microbiome. Curcumin may play a significant role in intestinal inflammatory disease treatment in the future, particularly as an adjuvant therapy.

Very early onset IBD: novel genetic aetiologies

PURPOSE OF REVIEW

To summarize the current understanding and recent advances on the genetic aetiology in the pathogenesis of very early onset inflammatory bowel disease (VEO-IBD).

RECENT FINDINGS

IBD is a chronic disorder of the gastrointestinal tract whose manifestation is a result of complex interactions between genetics, environment, immune system and microbial flora. Over 230 IBD risk loci have been reported in genome wide association studies but the genetic contribution of the majority of these loci in the manifestation of IBD is very low. Patients with VEO-IBD present with a more severe disease than older patients, characterized by poor prognosis and failure of conventional therapy. Recent studies have reported several monogenic diseases with high penetrance that present with IBD and IBD-like intestinal manifestations and overlap with primary immunodeficiencies. Increasing body of evidence supports a prominent role of genetics in the onset of VEO-IBD. New genetic variants and diagnoses in VEO-IBD are reviewed and current challenges in therapy with potential strategy to manage the disease are discussed.

SUMMARY

Functional analysis of the genes implicated in monogenic IBD has increased the understanding of the underlying pathobiological mechanism of the disease. This knowledge can be used to personalize medicine for specific patients, improving the standard of care and quality of life.

TGF-β in inflammatory bowel disease: a key regulator of immune cells, epithelium, and the intestinal microbiota

Inflammatory bowel disease (IBD) is defined as chronic intestinal inflammation, and includes ulcerative colitis and Crohn's disease. Multiple factors are involved in the pathogenesis of IBD, and the condition is characterized by aberrant mucosal immune reactions to intestinal microbes in genetically susceptible hosts. Transforming growth factor-β (TGF-β) is an immune-suppressive cytokine produced by many cell types and activated by integrins. Active TGF-β binds to its receptor and regulates mucosal immune reactions through the TGF-β signaling pathway. Dysregulated TGF-β signaling is observed in the intestines of IBD patients. TGF-β signal impairment in specific cell types, such as T-cells and dendritic cells, results in spontaneous colitis in mouse models. In addition, specific intestinal microbes contribute to immune homeostasis by modulating TGF-β production. In this review, we describe the role of TGF-β in intestinal immunity, focusing on immune cells, epithelium, and intestinal microbes. In addition, we present potential therapeutic strategies for IBD that target TGF-β.

Transforming Growth Factor-β Messenger RNA and Protein in Murine Colitis

Using a CD4+ T-cell-transplanted SCID mouse model of colitis, we have analyzed TGF-β transcription and translation in advanced disease. By in situ hybridization, the epithelium of both control and inflamed tissues transcribed TGF-β1 and TGF-β3 mRNAs, but both were expressed significantly farther along the crypt axis in disease. Control lamina propria cells transcribed little TGF-β1 or TGF-β3 mRNA, but in inflamed tissues many cells expressed mRNA for both isoforms. No TGF-β2 message was detected in either control or inflamed tissues. Immunohistochemistry for latent and active TGF-β1 showed that all cells produced perinuclear latent TGF-β1. The epithelial cell basal latent protein resulted in only low levels of subepithelial active protein, which co-localized with collagen IV and laminin in diseased and control tissue. Infiltrating cells expressed very low levels of active TGF-β. By ELISA, very low levels (0–69 pg/mg) of soluble total or active TGF-β were detected in hypotonic tissue lysates. TGF-β1 and TGF-β3 are produced by SCID mouse colon and transcription is increased in the colitis caused by transplantation of CD4+ T-cells, but this does not result in high levels of soluble active protein. Low levels of active TGF-β may be a factor contributing to unresolved inflammation.

Effects of ex-vivo and in-vivo treatment with probiotics on the inflammasome in dogs with chronic enteropathy

Inflammasomes coordinate the maturation of IL-1β and IL-18 in response to danger signals. They are vital for maintenance of intestinal homeostasis and have been linked to chronic intestinal inflammation in humans. Probiotics have been advocated as treatment in intestinal inflammation. So far, no study has investigated the role of the inflammasome in canine chronic enteropathy (CE). In this study the intestinal expression of inflammasome components was assessed in CE dogs compared to controls, when treated with probiotic Enterococcus faecium (EF) ex-vivo and in-vivo. RNA extraction from endoscopic biopsies and reverse-transcriptase quantitative PCR was performed for NLRP3, casp-1, IL-1β and IL-18. Immunohistochemistry was performed to investigate protein expression in tissues. Gene expression of casp-1 and NLRP3 was lower in CE samples than controls. Ex-vivo treatment with EF reduced NLRP3 expression in control samples. Treatment of CE dogs with EF alongside dietary intervention had no effect on gene expression. In contrast, IL-1β protein expression in CE decreased with dietary treatment (but not with probiotics). The results of this study suggest that the inflammasome or its components may be partially involved in the inflammatory process seen in CE, but distinct from intestinal inflammation in humans.

Interleukin-8 predicts 60-day mortality in premature infants with necrotizing enterocolitis

OBJECTIVE

The purpose of this study was to evaluate the predictiveness of circulating interleukin (IL)-8 for 60-day mortality in premature infants with necrotizing enterocolitis (NEC).

BACKGROUND

NEC affects up to 5% of premature infants and remains a leading cause of mortality among neonates.

METHODS

A total of 113 infants with surgically (n=50) or medically (n=63) treated NEC were retrospectively analyzed. Laboratory parameters including serum IL-8 were assessed at the diagnosis of NEC and during the preoperative workup.

RESULTS

The 60-day mortality was 19% (22/113), 10% (6/63) in medical and 33% (16/50) in surgical NEC. IL-8 levels significantly correlated with 60-day mortality (odds ratio: 1.38; CI 1.14-1.67; p=0.001). Median IL-8 levels at diagnosis were significantly higher in neonates who were later treated surgically (median=2625 pg/ml; range: 27-7500) compared with those treated medically (median=156 pg/ml; range: 5-7500; p<0.001). The AUC to discriminate between medical and surgical NEC was 0.82 (CI, 0.74-0.90), and an exploratory IL-8 cutoff point could be established at 1783 pg/ml (sensitivity of 90.5%; specificity of 59.2%).

CONCLUSIONS

Our findings that serum IL-8 (i) correlates directly with 60-day mortality and (ii) differs significantly between medically and surgically treated infants may change the process of therapeutic decision making in NEC.

Paradoxically increased FOXP3+ T cells in IBD do not preferentially express the isoform of FOXP3 lacking exon 2

BACKGROUND

Forkhead box P3 (FOXP3)+ regulatory T cells (Tregs) are critical for controlling inflammation in the gastrointestinal tract. There is a paradoxical increase of mucosal FOXP3+ T cells in patients with inflammatory bowel disease (IBD). These FOXP3+ cells were recently shown to include interleukin (IL)-17A-producing cells in Crohn's disease, resembling Th17 cells implicated in autoimmune diseases. FOXP3 inhibits IL-17A production, but a naturally occurring splice variant of FOXP3 lacking exon 2 (Δexon2) cannot.

AIMS

We hypothesized that IBD patients preferentially express the Δexon2 variant of FOXP3 so the paradoxically increased mucosal Tregs in IBD could represent cells expressing only Δexon2.

METHODS

We used antibodies and primers that can distinguish between the full-length and Δexon2 splice variant of FOXP3 to evaluate expression of these isoforms in human intestinal tissue by immunohistochemistry and quantitative polymerase chain reaction (PCR), respectively.

RESULTS

No difference in the expression pattern of Δexon2 relative to full-length FOXP3 was seen in ulcerative colitis or Crohn's disease versus non-IBD controls. By immunofluorescence microscopy and flow cytometry, we also did not find individual cells which expressed FOXP3 protein exclusively in the Δexon2 isoform in either IBD or control tissue. FOXP3+ mucosal CD4+ T cells from both IBD and control specimens were able to make IL-17A in vitro after phorbol myristate acetate (PMA) and ionomycin stimulation, but these cells did not preferentially express Δexon2.

CONCLUSIONS

Our data do not support the hypothesis that selective expression of FOXP3 in the Δexon2 isoform accounts for the inability of copious FOXP3+ T cells to inhibit inflammation or IL-17 expression in IBD.

Cytokines in inflammatory bowel disease

Over the past decade, much has been learned regarding the role of various cytokines in the pathogenesis of inflammatory bowel disease. Several cytokine ‘knockout’ models in mice have been shown to develop colitis, while alterations in the production of various cytokines has been documented in human Crohn's disease and ulcerative colitis. In recent years, attempts have been made to treat these diseases through modulation of cytokine production or action. This review focuses on the cytokines that have been implicated in the pathogenesis of inflammatory bowel disease. The evidence for and against a role for particular cytokines in intestinal inflammation is reviewed, as is the experimental and clinical data suggesting that cytokines are rational targets for the development of new therapies.

Interleukin 8 correlates with intestinal involvement in surgically treated infants with necrotizing enterocolitis

PURPOSE

The aim of this study was to test the predictive value of interleukin (IL) 8 in the assessment of intestinal involvement in necrotizing enterocolitis (NEC).

METHODS

Forty infants with surgically treated NEC were classified into 3 groups based on intestinal involvement during laparotomy: focal (n = 11), multifocal (n = 16), and panintestinal (n = 13). Preoperatively obtained serum levels of IL-8, C-reactive protein, white blood cell count, and platelet count were correlated with intestinal involvement using logistic regression models.

RESULTS

Interleukin 8 correlated significantly with intestinal involvement in infants with surgically treated NEC (odds ratio, 1.74; confidence interval, 1.27-2.39; P < .001). An exploratory IL-8 cutoff value of 449 pg/mL provided a specificity of 81.8% and sensitivity of 82.8% to discriminate focal from multifocal and panintestinal disease. An IL-8 cutoff value of 1388 pg/mL provided a specificity of 77.8% and a sensitivity of 76.9% to discriminate panintestinal disease from focal and multifocal disease.

CONCLUSIONS

To our knowledge, this is the first study to demonstrate a significant correlation of IL-8 with intestinal involvement in advanced NEC in a large patient population. Our results indicate that IL-8 may be a promising biomarker for assessing intestinal involvement in infants with advanced NEC.

IL-1-dependent, IL-1R1-independent resistance to gastrointestinal nematodes

IL-1 null mice are unable to expel the intestinal nematode Trichuris muris; whereas WT littermates exhibit sterile immunity. Intriguingly the essential signalling components IL-1R1 and IL-1R accessory protein (AcP) are dispensable for expulsion of this parasite. IL-1 is thus critical for CD4(+) Th2-mediated immunity to T. muris; however, this action is independent of the established IL-1 signalling receptor. We also present data demonstrating that both IL-1alpha and IL-1beta induce measurable effects on T. muris primed cells isolated from IL-1R1 or IL-1R AcP null mice. MLN cells from these mice restimulated with parasite antigen proliferated at a greater rate and produced more cytokines in response to exogenous IL-1. This ability to respond to IL-1 was restricted to these parasite-primed cells and importantly was not evident in cells from naïve gene null mice. These in vitro data are consistent with the observed ability of mice with compromised IL-1 signalling to expel the parasite, bolstering the premise that an alternative IL-1 signalling mechanism is accessible in the context of an intestinal helminth-driven Th2 immune response.

Enhanced expression of transcription factor GATA-4 in inflammatory bowel disease and its possible regulation by TGF-beta1

BACKGROUND

Transforming growth factor beta 1 (TGF-beta1) promotes epithelial healing in inflammatory bowel disease. We hypothesized that GATA-4, a transcription factor cooperating with TGF-beta signaling pathway, is upregulated by TGF-beta1 in the inflamed intestinal epithelium.

METHODS

Normal and inflamed intestinal samples were subjected to immunohistochemistry for GATA-4/6 and the TGF-beta signaling pathway components Smad2/3/4. Proliferation and apoptosis were analyzed using Ki-67 and in situ DNA 3'-end labeling assays and Bax and Bcl-2 immunohistochemistry. Furthermore, GATA-4 was assessed in intestinal Caco-2 cells stimulated with TGF-beta1, or interleukin-6 and tumor necrosis factor alpha.

RESULTS

GATA-4 was detected in only 20% of normal intestinal samples, but was upregulated in corresponding inflamed regions. GATA-6 expression remained unchanged during inflammation. TGF-beta1 and Smad3/4, but not Smad2, were expressed concomitantly with GATA-4 in inflamed bowel mucosa. In intestinal Caco-2 cells, TGF-beta1 upregulated GATA-4 and Smad2/3/4, whereas treatment with control cytokines had no effect. Inflammation was associated with increased epithelial cell apoptosis and the enhancement of Bcl-2, but not Bax.

CONCLUSIONS

We surmise GATA-4 expression is upregulated in inflamed intestine correlating with the activation of TGF-beta signaling pathway. We speculate that TGF-beta1 drives GATA-4 expression during intestinal inflammation, these two components cooperating to promote epithelial healing.

Cytokines in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a devastating intra-abdominal emergency in the newborn period. The disease involves bowel wall inflammation, ischemic necrosis, eventual perforation, and the need for urgent surgical intervention. Unrecognized or left untreated, the neonate can decompensate quickly, often progressing to shock, multisystem organ failure, and eventual death. During the past several years, a number of basic science and clinical trials have been established in an attempt to understand the pathophysiology of NEC. As many researchers feel that NEC develops as an uncontrolled inflammatory response that leads to intestinal ischemia, a large number of studies have been focused on the inflammatory cascade and the role that cytokines play within that cascade. Although a large amount of data has been generated from these studies, the events leading to the ischemic injury of the intestine are still not fully understood. This article will therefore focus on the key cytokines involved with NEC, in an attempt to present the current literature and studies that support their involvement.

11beta-hydroxysteroid dehydrogenase 1 and 2 expression in colon from patients with ulcerative colitis

BACKGROUND AND AIM

11beta-hydroxysteroid dehydrogenase (11betaHSD) is an enzyme responsible for the interconversion of active 11beta-hydroxysteroids (cortisol) into biologically inactive 11-oxosteroids (cortisone). The isoform 11betaHSD1 operates predominantly as a reductase converting cortisone to cortisol, whereas 11betaHSD2 catalyzes oxidation of cortisol to cortisone. This mechanism of peripheral metabolism of glucocorticoids has been suggested to be involved in increasing the availability of anti- inflammatory glucocorticoids as a response to inflammatory stimuli. The aim of this study therefore was to investigate the impact of inflammatory bowel disease on the expression of colonic 11betaHSD1 and 11betaHSD2.

METHODS

Quantitative real-time RT-PCR was used to assess messenger RNA for 11betaHSD1 and 11betaHSD2 in bioptic samples taken from patients with ulcerative colitis and in healthy controls, and in colon of rats with colitis induced by dextran sulfate sodium (DSS). Rat colonic fragments were used for assessment of local metabolism of glucocorticoids.

RESULTS

In both human and rat specimens colitis up-regulated the expression of colonic 11betaHSD1 mRNA and down-regulated 11betaHSD2 mRNA. A similar pattern was observed at the level of local metabolism of corticosterone. Oxidation of corticosterone to 11-dehydrocorticosterone was decreased and reduction of 11-dehydrocorticosterone to corticosterone was increased in colonic tissue of rats with DSS-colitis.

CONCLUSIONS

Colonic inflammation induces local glucocorticoid activation via 11betaHSD1 and impairs glucocorticoid inactivation via 11betaHSD2. The observed changes indicate a role for local metabolism of glucocorticoids in the control of colonic inflammation.

TGF-{beta}-dependent CD103 expression by CD8(+) T cells promotes selective destruction of the host intestinal epithelium during graft-versus-host disease

Destruction of the host intestinal epithelium by donor effector T cell populations is a hallmark of graft-versus-host disease (GVHD), but the underlying mechanisms remain obscure. We demonstrate that CD8⁺ T cells expressing CD103, an integrin conferring specificity for the epithelial ligand E-cadherin, play a critical role in this process. A TCR transgenic GVHD model was used to demonstrate that CD103 is selectively expressed by host-specific CD8⁺ T cell effector populations (CD8 effectors) that accumulate in the host intestinal epithelium during GVHD. Although host-specific CD8 effectors infiltrated a wide range of host compartments, only those infiltrating the intestinal epithelium expressed CD103. Host-specific CD8 effectors expressing a TGF-β dominant negative type II receptor were defective in CD103 expression on entry into the intestinal epithelium, which indicates local TGF-β activity as a critical regulating factor. Host-specific CD8 effectors deficient in CD103 expression successfully migrated into the host intestinal epithelium but were retained at this site much less efficiently than wild-type host-specific CD8 effectors. The relevance of these events to GVHD pathogenesis is supported by the finding that CD103-deficient CD8⁺ T cells were strikingly defective in transferring intestinal GVHD pathology and mortality. Collectively, these data document a pivotal role for TGF-β–dependent CD103 expression in dictating the gut tropism, and hence the destructive potential, of CD8⁺ T cells during GVHD pathogenesis.

Interleukin-6 regulation of transforming growth factor (TGF)-beta receptor compartmentalization and turnover enhances TGF-beta1 signaling

Transforming growth factor (TGF)-beta1 is a key cytokine involved in the pathogenesis of fibrosis in many organs, whereas interleukin (IL)-6 plays an important role in the regulation of inflammation. Recent reports demonstrate interaction between the two cytokines in disease states. We have assessed the effect of IL-6 on TGF-beta1 signaling and defined the mechanism by which this occurred. Stimulation of Smad-responsive promoter (SBE)4-Lux activity by TGF-beta1 was significantly greater in the presence of IL-6 than that induced by TGF-beta1 alone. Augmented TGF-beta1 signaling following the addition of IL-6 appeared to be mediated through binding to the cognate IL-6 receptor, the presence of which was confirmed by fluorescence-activated cell sorting and Stat-specific signaling. TGF-beta1 receptors internalize by both caveolin-1 (Cav-1) lipid raft and early endosome antigen 1 (EEA-1) non-lipid raft pathways, with non-lipid raft-associated internalization increasing TGF-beta1 signaling. Affinity labeling of TGF-beta1 receptors demonstrated that IL-6 stimulation resulted in increased partitioning of TGF-beta receptors to the non-lipid raft fraction. There was no change in expression of Cav-1; however, following IL-6 stimulation, co-immunoprecipitation demonstrated decreased association of IL-6 receptor with Cav-1. Increased TGF-beta1-dependent Smad signaling by IL-6 was significantly attenuated by inhibition of clathrin-mediated endocytosis and augmented by depletion of membrane cholesterol. These results indicate that IL-6 increased trafficking of TGF-beta1 receptors to non-lipid raft-associated pools results in augmented TGF-beta1 Smad signaling.

Increased serum concentrations and surface expression on peripheral white blood cells of decay-accelerating factor (cd55) in patients with active ulcerative colitis

Inflammatory stimuli induce expression and release of decay-accelerating factor (DAF), a complement-regulatory protein present on peripheral-blood cells. Therefore, in ulcerative colitis (UC), an inflammatory colonic disease in which activated leukocytes are involved, DAF may be released from leukocytes into the circulation. In this study we compared serum DAF concentrations and surface DAF expression on peripheral-blood cells in patients with UC with disease activity. Peripheral-blood samples were obtained from 60 patients with UC (30 with active and 30 with inactive disease) and 19 healthy volunteers. Serum DAF concentrations were determined by means of immunoassay, and surface DAF expression on blood cells was examined with the use of flow cytometry. Serum DAF concentrations in patients with active disease (mean 48.6 ng/mL) were significantly higher than those in patients whose disease was in remission (33.3 ng/mL; P =.0003) and those in healthy controls (32.3 ng/mL; P =.0007). Surface DAF expression on neutrophils, CD14+ monocytes, and subsets of lymphocytes in patients with active UC was significantly increased compared with that in patients with UC in remission and in healthy controls. The increased serum DAF concentrations and surface DAF expression on leukocyte fractions in patients with active disease fell to significantly lower levels when the disease had gone into remission after medical therapy. Serum DAF concentrations are increased in UC patients in relation to disease activity. The likely source of increased DAF concentrations is peripheral-blood leukocytes that have been activated as part of the UC disease process.

TGF-beta down-regulates IL-6 signaling in intestinal epithelial cells: critical role of SMAD-2

Interleukin-6 (IL-6) is a pro-inflammatory cytokine that plays an important role in the pathogenesis of inflammatory bowel disease. TGF-beta, a multifunctional cytokine, is a potent negative regulator of mucosal inflammation in the intestine. The aim of the present study is to determine possible cross-talk between IL-6 and TGF-beta signaling pathways. Model intestinal epithelial cell lines, Caco2-BBE were used. We show that TGF-beta receptor Type II is predominantly present in the basolateral membrane of intestinal epithelial cells. TGF-beta1 induces a time-dependent phosphorylation of Smad2 and co-immunoprecipitation of SMAD-2 with Smad-4 and its subsequently translocation to the nucleus. We show that pretreatment of cells with TGF-beta1 is associated with a down-regulation of IL-6 induced tyrosine phosphorylation of STAT1 and STAT3 and suppression of ICAM-1 expression. Furthermore, TGF-beta1 pretreatment resulted in a significant inhibition of IL-6 induced ICAM-1 promoter activity. TGF-beta mediated inhibition of IL-6 induced ICAM-1 expression was reversed by transfection with dominant negative Smad2 constructs. In conclusion, we show that: 1) TGF-beta receptor Type II is predominantly located on basolateral membrane and receptor stimulation activates Smad pathway; 2) TGF-beta1 down-regulates IL-6-induced tyrosine phoshorylation of STAT1 and STAT3 and ICAM-1 expression; and 3) Smad2 is required for the down-regulation of IL-6 signaling by TGF-beta. Collectively, our data demonstrate a cross-talk between TGF-beta and IL-6, and TGF-beta may play a role in the negative regulation of IL-6 signaling in intestinal epithelial cells.

Protective effects of recombinant human interleukin-10 on intestines of hypoxia-induced necrotizing enterocolitis in immature rats

BACKGROUND/PURPOSE

The role of cytokines in the pathogenesis of hemodynamic instability or tissue destruction in patients with necrotizing enterocolitis (NEC) remains undefined. The aim of this study was to determine the effects of recombinant human interleukin-102 (rhIL-10) on intestines of hypoxia-induced necrotizing enterocolitis in immature rats.

METHODS

The study was performed on 1-day-old Sprague Dawley rat pups. Group 1 (n = 8) served as nonhypoxic controls. Group 2 (untreated, n = 11) rats were subjected to hypoxia-reoxygenation (H/O) and then were returned to their mothers. Group 3 (rhIL-10 treated, n = 10) rats were subjected to H/O, were returned to their mothers, and were treated with rhIL-10 (75 microgram/kg subcutaneously) for the next 3 days. All animals were killed on day 4, and intestine specimens were obtained to determine the tissue level of malondialdehyde (MDA) and histologic changes.

RESULTS

The microscopic lesions in the untreated rats were virtually the same as those seen in neonatal NEC, with destruction of villi and crypts, and in some cases extension to the muscularis. In contrast, in the rats treated with rhIL-10, lesions were limited essentially to the very tips of the villi. Intestinal injury score was significantly less in the rhIL-10-treated rats than in the untreated rats (P <.05). In the rhIL-10-treated group, Malondialdehyde (MDA) levels were not significant in comparison to the control group. In the untreated group, MDA levels were significantly increased when compared with the control and the rhIL-10-treated groups (P <.001 and P <.05, respectively).

CONCLUSION

RhIL-10 has a protective effect on intestinal injury in NEC in an experimental model.

Site-dependent production of transforming growth factor beta1 in colonic mucosa: its possible role in tumorigenesis of the colon

Transforming growth factor (TGF) beta1 has an antitumorigenic role in the gastrointestinal tract and may be associated with the development of colon neoplasia. In the present study we investigated whether TGF-beta1 production in mucosa is lower in the distal colon, which is where clinical evidence shows that the incidence of colon neoplasia is higher, and whether TGF-beta1 levels were lower in the mucosa of patients with colon adenoma. Production of colon mucosa TGF-beta1 was investigated by means of a 24-hour organ culture with biopsy specimens taken from different segments of the colon of 58 normal subjects by using an enzyme immunoassay. TGF-beta1 production in colon mucosa from locations near the site of sporadic adenoma was also investigated in 46 patients. TGF-beta1 production gradually increased from the rectum to the ascending colon in a statistically significant manner in both normal (r = 0.77, P < .0001) and adenoma-bearing (r = 0.8, P < .0001) mucosa. When TGF-beta1 production was compared between normal and adenoma-bearing mucosa, levels were lower in the latter, although statistically significant results were seen only in the transverse colon (P < .05). TGF-beta1 production has clear site dependency, being lowest in the rectum and highest in the ascending colon. Furthermore, low levels of TGF-beta1 are associated with the development of adenoma. Our results suggest the possibility that this site dependency is associated with the higher epidemiologic incidence of colon neoplasia in the distal colon.

Transfer of interleukin-4 and interleukin-10 in patients with severe inflammatory bowel disease of the rectum

Inflammatory bowel disease (IBD) comprises the two disorders ulcerative colitis (UC) and Crohn's disease (CD). Although the etiology is still unclear, initiation and aggravation of the inflammatory processes seem to be due to a massive local mucosal immune response. An increased number of greatly activated macrophages seems to contribute to the onset of IBD by expressing upregulated costimulatory molecules (e.g., CD80/CD86) and a cytokine profile favouring a type I proinflammatory response. The release of interleukin 2 (IL-2) and Interferon-gamma (IFN-gamma) by naive T lymphocytes predominantly stimulates cytotoxic T lymphocytes, macrophages, and natural killer (NK) cells and increases the antigen-presenting potential of all these cell types. Opposite this proinflammatory immune reaction a compensatory type II antiinflammatory response has been suggested in the inflamed mucosa, involving mainly interleukin 4 and interleukin 10. Both cytokines are able to down-regulate inflammatory mediators including tumor necrosis factor-alpha (TNF-alpha) and interleukin 1 and favor a humoral immune response. The main goal of this clinical trial is the local liposome-mediated gene transfer of these two antiinflammatory cytokines, interleukin 4 and interleukin 10, in patients with severe IBD of the rectum. This local administration of antiinflammatory cytokines will avoid toxic systemic side effects, prevents blocking of the beneficial effects of proinflammatory cytokines, e.g., TNF-alpha in other tissue compartments and increases the local concentration of interleukin 4 and interleukin 10 over a prolonged period of time. The combined effects of IL-4 and IL-10 have been shown to shift the Th1/Th2 cell activation in favor of a Th2 immune response which seems to be essential for fighting against the inflammation and ultimative healing.

Cytokine mRNA expression in leprosy: a possible role for interferon-gamma and interleukin-12 in reactions (RR and ENL)

Leprosy patients during the natural course of the disease may develop reactional episodes, namely reversal reaction (RR) and erythema nodosum leprosum (ENL). Immunological events described as occurring during RR indicate up-regulation of the immune response, whereas in ENL the events are not fully understood. The aim of this study was to analyse the in vivo pattern of cytokine gene expression in the reactional states of leprosy. Peripheral blood mononuclear cells (PBMC, n = 14) and tissue samples (n = 17) obtained from patients with ENL and RR were obtained and assayed by RT-PCR. PBMC obtained from unreactional patients (n = 15) and normal individuals (n = 5) were also assessed. Expression of interferon (IFN)gamma, granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin (IL)-2Rp55, perforin and IL-1beta mRNA in PBMC were detected mostly in ENL/RR patients, but not in unreactional patients. Likewise, cytokines such as IL-6, IL-8, tumour necrosis factor (TNF)alpha and TNFbeta were also present in reactional and tuberculoid patients as opposed to lepromatous leprosy (BL/LL). Interestingly, the majority of ENL/RR patients showed messages for IL-6, IL-10, IL-12 and TNFalpha in the skin. IFNgamma was detected in 84.6% (ENL) and 100% (RR) of the patients, whereas IL-4 was detected only in few individuals (38.5 and 25%, respectively). Although mRNA expression and protein levels may be different, the data reported in this study suggest a cytokine mRNA profile that seems to be indistinguishable for RR and ENL. In addition, it shows up-regulation of immuno-inflammatory cytokines in the blood and tissue of the same patient examined before and during reaction. Furthermore, it is suggested that this pattern of response results from an immunological reactivation that might lead to an acute inflammatory response in both reactional episodes.

Circulating pro- and counterinflammatory cytokine levels and severity in necrotizing enterocolitis

OBJECTIVES

To evaluate the relationship between the severity of necrotizing enterocolitis (NEC) and circulating concentrations of proinflammatory cytokines interleukin (IL)-1beta and IL-8 and counterinflammatory cytokines IL-1 receptor antagonist (IL-1ra) and IL-10. These cytokines have been associated with bowel injury or inflammation and may be released more slowly or later than previously examined cytokines. Also, to determine if any one of these cytokines will predict the eventual severity of NEC when measured at symptom onset.

METHOD

Serial blood samples at onset, 8, 24, 48, and 72 hours were obtained from newborn infants with predefined signs and symptoms of NEC. Normal levels were defined from weight-, gestation-, and age-matched controls. Concentrations of the four cytokines were determined by enzyme-linked immunosorbent assay and compared throughout the time period by stage of NEC, using sepsis as a co-factor. Mean concentrations of each cytokine at onset were compared with the controls. Threshold values were obtained with the best combination of high sensitivity and high specificity for defining stage 1 NEC or for diagnosing stage 3 NEC at onset.

RESULTS

There were 12 cases of stage 1, 18 cases of stage 2, and 6 cases of stage 3 NEC included in the study, as well as 20 control infants. Concentrations of IL-8 and IL-10 were significantly higher in infants with stage 3 NEC from onset through 24 hours compared with infants with less severe NEC. At onset, concentrations of all four cytokines were significantly higher in stage 3 NEC. To identify, at onset, the infants with a final diagnosis of stage 3 NEC, an IL-1ra concentration of >130 000 pg/mL had a sensitivity of 100% and a specificity of 92%. At 8 hours, an IL-10 concentration of >250 pg/mL had a sensitivity of 100% and a specificity of 90% in identifying stage 3 NEC in infants with symptoms suggestive of NEC at onset.

CONCLUSIONS

The severity of NEC and its systemic signs and symptoms are not due to a deficiency of counterregulatory cytokines. In fact, mean concentrations of IL-1ra in NEC are higher than what has been reported in other populations. The cytokines IL-8, IL-1ra, and IL-10 are released later or more slowly after a stimulus and may be more useful in identifying, within hours of symptom onset, which infant will develop significant NEC.

Growth factors in inflammatory bowel disease

The pathogenesis of both ulcerative colitis and Crohn's disease is unknown but these forms of inflammatory bowel disease (IBD) may be associated with an inability of the intestinal mucosa to protect itself from luminal challenges and/or inappropriate repair following intestinal injury. Numerous cell populations regulate these broad processes through the expression of a complex array of peptides and other agents. Growth factors can be distinguished by their actions regulating cell proliferation. These factors also mediate processes such as extracellular matrix formation, cell migration and differentiation, immune regulation, and tissue remodeling. Several families of growth factors may play an important role in IBD including: epidermal growth factor family (EGF) [transforming growth factor alpha (TGF alpha), EGF itself, and others], the transforming growth factor beta (TGF beta) super family, insulin-like growth factors (IGF), fibroblast growth factors (FGF), hepatocyte growth factor (HGF), trefoil factors, platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF) and others. Collectively these families may determine susceptibility of IBD mucosa to injury and facilitate tissue repair.

Growth factors in inflammatory bowel disease

The pathogenesis of both ulcerative colitis and Crohn's disease is unknown but these forms of inflammatory bowel disease (IBD) may be associated with an inability of the intestinal mucosa to protect itself from luminal challenges and/or inappropriate repair following intestinal injury. Numerous cell populations regulate these broad processes through the expression of a complex array of peptides and other agents. Growth factors can be distinguished by their actions regulating cell proliferation. These factors also mediate processes such as extracellular matrix formation, cell migration and differentiation, immune regulation, and tissue remodeling. Several families of growth factors may play an important role in IBD including: epidermal growth factor family (EGF) [transforming growth factor alpha (TGF alpha), EGF itself, and others], the transforming growth factor beta (TGF beta) super family, insulin-like growth factors (IGF), fibroblast growth factors (FGF), hepatocyte growth factor (HGF), trefoil factors, platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF) and others. Collectively these families may determine susceptibility of IBD mucosa to injury and facilitate tissue repair.

Transforming growth factor-betas and their signaling receptors are coexpressed in Crohn's disease

OBJECTIVE

To evaluate mechanisms that contribute to tissue repair and tissue remodeling in Crohn's disease (CD).

SUMMARY BACKGROUND DATA

Transforming growth factor-betas (TGF-betas) are involved in different chronic inflammatory disorders. They function by binding to two receptors, type I (TbetaR-I) subtype ALK5 and type II (TbetaR-II), which are concomitantly required for signal transduction.

METHODS

Tissues were obtained from 18 patients with CD (10 female patients, 8 male patients, median age 38.7 years [range 16 to 58 years]) undergoing surgery because of CD-related complications. Tissue samples of 18 healthy organ donors (10 female subjects, 8 male subjects, median age 50.3 years [range 15 to 65 years]) served as controls. The expression and localization of TGF-beta1, TGF-beta2, TGF-beta3, TbetaR-IALK5, TbetaR-II, and TbetaR-III were studied by Northern blot analysis, in situ hybridization, and immunohistochemistry.

RESULTS

On Northern blot analysis, 94% of the CD samples exhibited enhanced TGF-beta1, TGF-beta3, and TbetaR-II mRNA expression compared with controls. TGF-beta2 was increased in 72%, TbetaR-IALK5 in 72%, and TbetaR-III in 82% of the patients with CD. On in situ hybridization and immunohistochemical analysis, TGF-beta1, TbetaR-IALK5, and TbetaR-II were seen to be colocalized in the lamina propria cells and in the lymphocytes closest to the luminal surface, but also in the remaining epithelial cells, and in fibroblasts of CD tissue samples.

CONCLUSIONS

The concomitant overexpression of TGF-betas and their signaling receptors in CD points to a potential role of these regulatory molecules in the pathophysiology of CD. Activation of TGF-beta-mediated pathways might promote the repair of mucosal injury by enhancing the process of reepithelization, but might also contribute to extracellular matrix generation and subsequently to intramural fibrosis and intestinal obstruction.

Cytokine-stimulated release of decay-accelerating factor (DAF;CD55) from HT-29 human intestinal epithelial cells

Expression of DAF (CD55) is enhanced on colonic epithelial cells of patients with ulcerative colitis (UC), and stool DAF concentrations are increased in patients with active disease. Cytokines are known to modulate DAF expression in various human cells, and lesions of UC reveal altered profiles of cytokine production. In this study, we evaluate the effects of various cytokines, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, and interferon-gamma (IFN-gamma), on the synthesis and kinetics of DAF protein in HT-29 human intestinal epithelial cells. Using flow cytometry and an ELISA, we found that HT-29 cells constitutively express DAF on the cell surface and spontaneously release DAF into the culture supernatant under standard culture conditions. When the culture supernatant was centrifuged at 100000g, nearly a half of DAF was precipitated, indicating that one half of the released DAF was present as a membrane-bound form and the other half as a soluble form. Analysis of the culture supernatant of biotin surface-labelled HT-29 cells suggested that the soluble form DAF was derived by secretion from within the cell or by cleavage from the cell surface. Among the cytokines, IL-4 markedly, and IL-1beta moderately, enhanced the expression and the release of DAF. Actinomycin D, cycloheximide, and brefeldin A inhibited the increase in DAF release induced by IL-4 and IL-1beta stimulation. These results suggest that DAF is released from intestinal epithelial cells in response to cytokine stimulation and that IL-4 and IL-1beta are possible cytokines involved in DAF release into the colonic lumen of patients with UC.

Gluten induces an intestinal cytokine response strongly dominated by interferon gamma in patients with celiac disease

BACKGROUND & AIMS

Celiac disease appears to be a T cell-mediated enteropathy induced by gluten in genetically predisposed individuals. Duodenal biopsy specimens from patients with celiac disease and histologically normal controls were investigated to see if cytokine expression is related to disease activity.

METHODS

Cytokine messenger RNA (mRNA) expression was determined by quantitative reverse-transcription polymerase chain reaction and in situ expression by immunohistochemistry.

RESULTS

In normal controls, mRNA levels were usually below the quantitative limit, even after in vitro gluten stimulation. By contrast, interferon (IFN)-gamma mRNA was increased more than 1000-fold in untreated disease. In vitro gluten stimulation of specimens from treated patients (gluten-free diet) increased IFN-gamma mRNA to the levels of untreated patients. In addition, increased mRNA levels for interleukin (IL)-2, IL-4, IL-6, and tumor necrosis factor alpha were found after such stimulation, whereas mRNA for IL-5, IL-10, and IL-12p40 was usually below the quantitative level. Biopsy specimens from untreated patients contained on average 10-fold more lamina propria cells positive for IFN-gamma than normal controls, whereas cells containing IL-4 were rare in both subject groups.

CONCLUSIONS

The results show that mucosal gluten exposure in patients with celiac disease rapidly elicits high levels of IFN-gamma expression and lower levels of IL-2, IL-4, IL-6, and tumor necrosis factor alpha even in the virtual absence of IL-12.

Connective tissue growth factor: a novel regulator of mucosal repair and fibrosis in inflammatory bowel disease?

Inflammatory bowel disease (IBD) is a multifactorial disorder which is characterized by massive damage of the epithelium and the underlying mesenchyme of the intestine. Due to the potent effect of connective tissue growth factor (CTGF) on fibroblast proliferation and connective tissue deposition we speculated about a possible role of this mitogen in IBD. Here we demonstrate a strikingly increased expression of CTGF mRNA in surgical specimens of patients suffering from two forms of IBD, Crohn's disease and ulcerative colitis. In most specimens, the levels of CTGF mRNA correlated with the degree of inflammation as assessed by histological analysis of adjacent tissue samples and by expression analysis of the pro-inflammatory cytokine interleukin-1 beta. However, areas of little inflammation which were characterized by severe fibrosis also revealed high levels of CTGF mRNA. Expression of transforming growth factor beta-1 (TGF-beta 1), the only known inducer of CTGF so far, as well as of the CTGF target genes collagen I alpha 1, fibronectin and integrin alpha 5 revealed a strong correlation with the expression of CTGF. These data suggest a prominent role of CTGF in the repair of mucosal injury in IBD and in the aberrant deposition of extracellular matrix leading to fibrosis and stenosis, one major complication in IBD, especially in Crohn's disease.

Alteration of gene expression by intestinal epithelial cells precedes colitis in interleukin-2-deficient mice

Intestinal epithelial cells may be actively involved in the immunoregulatory pathways leading to intestinal inflammation. The aim of this study was to assess expression by intestinal epithelial cells of cytokines with potential involvement in the development of intestinal inflammation in interleukin (IL)-2-deficient [(-/-)] mice. Wild-type mice, mice heterozygous for the disrupted IL-2 gene, and IL-2(-/-) mice were studied at 6, 16, and 24 wk of age. The mRNA levels of transforming growth factor-beta 1 (TGF-beta 1), tumor necrosis factor-alpha (TNF-alpha), IL-1 beta, IL-6, IL-15, KC, JE, and CD14 in colonic and small intestinal epithelial cells were assessed by Northern blot analysis. CD14 was also measured by Western blotting and reverse transcriptase polymerase chain reaction (RT-PCR). TGF-beta 1 mRNA was constitutively expressed in both colonic and small intestinal epithelial cells with increased expression in the colonic epithelium of colitic mice. CD14 was detected only in colonic epithelial cells, and mRNA levels increased severalfold in IL-2(-/-) mice with colitis. Northern analysis demonstrated increased levels of TGF-beta 1 and CD14 mRNA in colonic epithelial cells of IL-2(-/-) mice before the development of signs of colitis. CD14 mRNA and protein expression in the epithelial cells of colitic mice were confirmed by RT-PCR and Western blot analysis of isolated cells. In addition, IL-2(-/-) mice also expressed increased levels of IL-15 mRNA in small intestinal and colonic epithelial cells compared with heterozygous control mice. TNF-alpha, IL-1 beta, IL-6, KC, and JE mRNAs were only detectable in colonic epithelial cells of mice after the onset of colitis. Enhanced expression of TGF-beta 1, IL-15, and CD14 by colonic epithelial cells may play a role in the subsequent development of colitis in IL-2(-/-) mice.

Induction and modulation of acute-phase response by protein malnutrition in rats: comparative effect of systemic and localized inflammation on interleukin-6 and acute-phase protein synthesis

The acute-phase protein (APP) response is regulated by cytokines such as interleukin-6 (IL-6), interleukin-1 (IL-1) and tumor necrosis factor (TNF), but may also be influenced by malnutrition. The aims of this study were as follows: 1) to determine in rats the effect of a protein-deficient diet on IL-6 mRNA expression in intestine, liver and peripheral blood mononuclear cells (PBMC), and on alpha-1 acid glycoprotein (AGP) and alpha-2 macroglobulin (A2M) serum levels and hepatic mRNA expression; 2) to compare, in protein-deficient rats, the IL-6 and APP responses after a turpentine (TO)- or a lipopolysaccharide (LPS)-induced inflammation; and 3) to determine the effect of a protein malnutrition on IL-6 mRNA expression in rat PBMC treated ex vivo with LPS. Interleukin-6 mRNA was present in intestine and PBMC but not in the liver of malnourished rats, and was absent in any tissue or cells of controls. A2M was present in the serum from malnourished rats but not after refeeding. AGP mRNA expression was not influenced by protein malnutrition. In malnourished rats, IL-6 serum level peaked later than in controls after TO and LPS treatment. In malnourished TO-treated rats, A2M mRNA increased earlier than in controls and remained detectable later than in controls. AGP mRNA expression after TO was not influenced by protein malnutrition. In PBMC of malnourished rats, LPS-induced IL-6 mRNA expression occurred earlier and lasted longer than in controls. Our results indicate that protein malnutrition by itself induces IL-6 and A2M expression, and that it modulates the APP response to inflammation.

Insulin-like growth factor-I partially attenuates colonic damage in rats with experimental colitis induced by oral dextran sulphate sodium

BACKGROUND

Administration of insulin-like growth factor-I (IGF-I) results in selective growth of the gastrointestinal tract. We investigated the effects of IGF-I on the colonic damage induced by oral dextran sulphate sodium (DSS) in the rat.

METHODS

Rats consumed 2% DSS in the drinking water for 10 days to induce colitis. Pumps were implanted on day 3 to deliver IGF-I for 7 days. Colonic histopathology and immunolocalization of transforming growth factor-beta1 (TGF-beta1) were assessed on day 10.

RESULTS

Compared with the colon of vehicle-treated rats consuming DSS, IGF-I increased the numbers of goblet cells by 76%, reduced the proportion of lamina propria cells expressing TGF-beta1, and reduced the thickness of submucosal and muscularis externa layers by 26% and 20%, respectively.

CONCLUSIONS

We conclude that the effects of IGF-I treatment on the colonic epithelium may be mediated directly, whereas the reduced inflammation in the mucosa and submucosa may be mediated by a mechanism other than up-regulation of TGF-beta1-mediated immunosuppression.

Analysis of germline and expressed T cell receptor variable region genes in Crohn's disease

A possible role of the T cell receptor genes in the pathogenesis of Crohn's disease was investigated by 1) comparison of restriction fragment length polymorphisms at the T cell receptor beta chain locus in 64 Crohn's patients and 64 normal controls; 2) semi-quantitative polymerase chain reaction analysis of T cell receptor beta and alpha chain variable region gene expression by lamina propria lymphocytes from resected segments of diseased terminal ileum. We found no association between any of the restriction fragment length polymorphisms and Crohn's disease using polymorphic markers spanning the T cell receptor beta chain locus. Analysis of T cell receptor V beta and V alpha gene expression showed that expression of T cell receptor V region families in terminal ileum lymphocytes from patients with active Crohn's disease was indistinguishable from the lymphocytes found in normal terminal ileum. These data fail to support susceptibility to Crohn's disease being associated with the T cell beta chain antigen receptor genotype. No restricted or dominant T cell receptor variable region gene expression was found in Crohn's disease tissue, compared to normal terminal ileum.

Mucosal inflammatory cytokine production by intestinal biopsies in patients with ulcerative colitis and Crohn's disease

Chronic inflammation in inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis) may be attributed partly to increased secretion of inflammatory cytokines. The aim of this study was to investigate simultaneously the spontaneous release patterns of tumor necrosis factor-alpha (TNF-alpha), interleukin-1-beta (IL-1 beta), and interleukin-6 (IL-6) by organ cultures of inflamed mucosa from IBD patients. Organ cultures of involved IBD mucosa spontaneously produced increased amounts of TNF-alpha, IL-1 beta, and IL-6 compared to normal mucosa. The patterns of cytokine release between Crohn's disease and ulcerative colitis organ cultures were not significantly different. Increased inflammatory cytokine production by lamina propria mononuclear cells (LPMCs) and mucosa treated with EDTA suggests that these cytokines originate mainly from LPMCs. These results confirm the role of inflammatory cytokines in IBD and shed a new light on the role of TNF-alpha in IBD.

Transforming growth factor-beta in GI neoplasia, wound healing and immune response

The last decade has been marked by tremendous advances in the biochemical and functional characterization of TGF-betas and their receptors in normal and transformed cells. TGF-betas have been shown to modulate proliferation, differentiation and motility of different cell types in a number of in vitro model systems and in some cases with some intriguing results. It is obvious that there is no simple pattern that explains the TGF-betas biological activity in vitro and their effects on cell behaviour need to be assessed in the context of an appropriate physiological cellular environment. Cell-cell and cell-matrix interactions, the differentiating status of the cell together with the functional activity of other soluble growth factors can influence how TGF-betas modulate cell behaviour. However, the overwhelming interest in this field shown by clinicians and basic scientists is rapidly increasing our understanding of how growth factors such as TGF-betas regulate the homeostasis of the GI mucosa and their role in gastrointestinal carcinogenesis.

Role of cytokines and platelet-activating factor in inflammatory bowel disease. Implications for therapy

BACKGROUND

Platelet-activating factor (PAF) and cytokines, such as interleukins, tumor necrosis factor, and others, are thought to play a role in the inflammatory process involving gastrointestinal disorders such as Crohn's disease, ulcerative colitis, ischemic colitis, or antibiotic-associated colitis.

PURPOSE

This study was undertaken to review the latest literature on the role of PAF and cytokines in the genesis of inflammatory bowel disease and implications for therapy and management.

RESULTS

PAF is an endogenous phospholipid involved in hypersensitivity and inflammatory reactions such as platelet and neutrophil aggregation, vasodilation, increased vascular permeability, and leukocyte adhesion, which have been associated with inflammatory processes. Cytokines are peptides that regulate and coordinate inflammatory and immunologic responses. Increased production of cytokines has been reported during Crohn's disease and ulcerative colitis and is correlated with disease activity.

CONCLUSIONS

Because PAF and cytokines may have an important role in the pathogenesis of inflammatory bowel disease, their inhibition by specific antagonists, mediators, or other agents such as steroids may have a potential therapeutic benefit in treatment and management of these inflammatory diseases in the near future.

Altered Th1/Th2 cytokine profiles in the intestinal mucosa of patients with inflammatory bowel disease as assessed by quantitative reversed transcribed polymerase chain reaction (RT-PCR)

Cytokines serve a central function as key factors in the regulation of the intestinal immune response and mediation of tissue damage in inflammatory bowel disease (IBD). Abnormalities in the expression of immunoregulatory cytokines such as IL-2, IL-4, IL-10 and interferon-gamma (IFN-gamma) may indicate a dysregulation of intestinal immunity probably associated with pathogenic events. Therefore, cytokine mRNA concentrations were determined in the mucosa of patients with IBD at sites of active (n = 13) and inactive (n = 12) ulcerative colitis (UC), active (n = 11) and inactive (n = 11) Crohn's disease (CD) and in control patients (n = 14) using quantitative RT-PCR. IL-10 mRNA concentrations were significantly increased in patients with both active UC (P < 0.001) and active CD (P < 0.005) compared with control patients. IFN-gamma mRNA concentrations were also significantly increased both in patients with active UC (P < 0.02) and active CD (P < 0.05) compared with control patients, whereas IL-2 mRNA levels were significantly (P < 0.02) increased only in active CD. IL-4 mRNA expression in the intestinal mucosa was frequently below the detection limit. Our results demonstrate that chronic intestinal inflammation in patients with CD is characterized by an increase of Th1-like cytokines. Furthermore, the increased IL-10 mRNA expression at sites of active IBD suggests that IL-10 is an important regulatory component involved in the control of the inflammatory response in inflammatory bowel disease.

Anti-inflammatory effects of CGP 47969A, a novel inhibitor of proinflammatory cytokine synthesis, in rabbit immune colitis

BACKGROUND & AIMS

Proinflammatory cytokines such as interleukin (IL) 1, IL-8, and tumor necrosis factor (TNF) have been implicated as primary mediators of intestinal inflammation. The aim of the present study was to determine the effects of a novel cytokine antagonist (CGP 47969A) in a rabbit model of acute colitis.

METHODS

Colitis was induced using the formalin-immune complex technique. Animals were pretreated intrarectally with CGP 47969A (30, 10, or 3 mg/kg), hydrocortisone (0.8 mg/kg), or vehicle (4 mL saline) 2 hours before the induction of colitis and twice daily thereafter until death 48 hours after the induction of colitis. The severity of inflammation of colonic tissue was assessed using histological analysis and myeloperoxidase activity assay, and IL-1 alpha, IL-8, TNF-alpha, and IL-1 receptor antagonist levels were determined.

RESULTS

Compared with vehicle, CGP 47969A (10 mg/kg) significantly reduced the acute inflammatory index by 58%, edema by 67%, necrosis by 99%, and myeloperoxidase activity by 49% (all P < 0.02) with efficacy similar to that of steroids. These effects were associated with a significant inhibition of colonic IL-1 alpha and IL-8 by 56% and 90%, respectively (p < 0.01).

CONCLUSIONS

Administration of CGP 47969A reduces inflammation and tissue damage in rabbit immune complex colitis through mechanisms involving the inhibition of mucosal proinflammatory cytokines.

Direct evidence of monocyte recruitment to inflammatory bowel disease mucosa

Alterations in phenotype and function of intestinal macrophages occur in inflammatory bowel disease (IBD) but it is unclear whether these changes result from the recruitment of circulating monocytes to the intestine or from proliferation of resident intestinal macrophages. We sought to demonstrate the arrival of blood monocytes, the precursors of macrophages, in IBD mucosa. Peripheral blood mononuclear cells were isolated from 23 patients with clinically active intestinal inflammation (13 Crohn's disease, eight ulcerative colitis, two infective colitis), then radiolabelled with 99mtechnetium (Tc)-stannous colloid (n = 13) or 111indium (In)-oxine (n = 10) before re-injection and abdominal scanning. Four patients had demonstrable intestinal monocyte uptake using [99mTc]-stannous colloid, while six [111In]-oxine-labelled monocyte scans were positive. Uptake sites correlated with actively inflamed regions. Patients demonstrating monocyte uptake had been treated with corticosteroids for a significantly (P < 0.02) shorter duration (median 3 vs 20 days) than those with negative scans. There was no significant difference between positive and negative scans for disease category, clinical or histological disease, activity, or radioisotope used. Biopsies of inflamed mucosa from two patients suffering ulcerative colitis who had positive scans showed a high proportion of CD14-positive macrophages, 4-9% of which contained autoradiographic grains. These results demonstrate that blood monocytes are recruited to the mucosa of actively inflamed bowel, and suggest that this process may be inhibited by corticosteroids. Moreover, the phenotype of the recently-arrived monocytes indicates their susceptibility to stimulation by lipopolysaccharide, and suggests a mechanism for the continuing inflammation in the bacterial product-rich milieu of IBD.

Elevation of interleukin-6 in inflammatory bowel disease is macrophage- and epithelial cell-dependent

Local interleukin-6 (IL-6) activity was studied using colonic mucosal tissues in inflammatory bowel disease (IBD) and inflammatory control patients. Active IBD specimens exhibited significantly higher IL-6 activity than control specimens in both cultures of isolated lamina propria mononuclear cells (LPMC) and mucosal tissues with an increased number of IL-6-producing cells. However, the activity in inactive IBD or inflammatory controls did not differ from controls. Northern blot analysis demonstrated IL-6 messenger RNA in LPMC and colonic epithelial cells isolated from active IBD specimens but not in control cells. Furthermore, immunofluorescent microscopic study of active IBD specimens showed more conspicuous staining of IL-6 in infiltrating LPMC (mostly CD68+ cells) and colonic epithelial cells. These results suggest that elevation of local IL-6 activity may be a characteristic feature of active IBD and both macrophages and colonic epithelial cells are the major cell types responsible for this phenomenon.