Current view of the immunopathogenesis in inflammatory bowel disease and its implications for therapy

Ginsenoside Rg1 attenuates dextran sodium sulfate-induced ulcerative colitis in mice

Ulceration colitis (UC) is a chronic and recurrent inflammatory disorder in the gastro-intestinal tract. The purpose of our study is to explore the potential mechanisms of ginsenoside Rg1 (GS Rg1) on dextran sulfate sodium (DSS)-induced colitis in mice and lipopolysaccharide (LPS)-induced RAW 264.7 cells. Acute colitis was induced in male C57BL/6 mice. In vitro model of LPS-induced RAW 264.7 cells to simulate enteritis model. The disease activity index (DAI), colon length, body weight and histopathological analysis were performed in vivo. Pro-inflammatory cytokines and markers for oxidative and anti-oxidative stress, MPO level were measured in vivo and in vitro. Nuclear erythroid 2-related factor 2 (Nrf2) and NF-?B p65 protein levels were analyzed using western blotting. Our results indicated that the UC models were established successfully by drinking DSS water. GS Rg1 significantly attenuated UC-related symptoms, including preventing weight loss, decreasing DAI scores, and increasing colon length. GS Rg1 ameliorated the DSS-induced oxidative stress. IL-1beta, IL-6, and TNF-alpha levels were significantly increased in serum and cell supernatant effectively, while treatment with the GS Rg1 significantly reduced these factors. GS Rg1 reduced MPO content in the colon. GS Rg1 treatment increased SOD and decreased MDA levels in the serum, colon, and cell supernatant. GS Rg1 restored the Nrf-2/HO-1/NF-?B pathway in RAW 264.7 cells and UC mice, and these changes were blocked by Nrf-2 siRNA. Overall, GS Rg1 ameliorated inflammation and oxidative stress in colitis via Nrf-2/HO-1/NF-kappaB pathway. Thus, GS Rg1 could serve as a potential therapeutic agent for the treatment of UC.

Role of CD34 in inflammatory bowel disease

Inflammatory bowel disease (IBD) is caused by a variety of pathogenic factors, including chronic recurrent inflammation of the ileum, rectum, and colon. Immune cells and adhesion molecules play an important role in the course of the disease, which is actually an autoimmune disease. During IBD, CD34 is involved in mediating the migration of a variety of immune cells (neutrophils, eosinophils, and mast cells) to the inflammatory site, and its interaction with various adhesion molecules is involved in the occurrence and development of IBD. Although the function of CD34 as a partial cell marker is well known, little is known on its role in IBD. Therefore, this article describes the structure and biological function of CD34, as well as on its potential mechanism in the development of IBD.

Personalized redox medicine in inflammatory bowel diseases: an emerging role for HIF-1α and NRF2 as therapeutic targets

Inflammatory bowel diseases (IBD), encompassing Crohn's disease (CD) and ulcerative colitis (UC), are intimately associated with inflammation and overproduction of reactive oxygen species (ROS). Temporal and inter-individual variabilities in disease activity and response to therapy pose significant challenges to diagnosis and patient care. Discovery and validation of truly integrative biomarkers would benefit from embracing redox metabolomics approaches with prioritization of central regulatory hubs. We here make a case for applying a personalized redox medicine approach that aims to selectively inhibit pathological overproduction and/or altered expression of specific enzymatic sources of ROS without compromising physiological function. To this end, improved 'clinical-omics integration' may help to better understand which particular redox signaling pathways are disrupted in what patient. Pharmacological interventions capable of activating endogenous antioxidant defense systems may represent viable therapeutic options to restore local/systemic redox status, with HIF-1α and NRF2 holding particular promise in this context. Achieving the implementation of clinically meaningful mechanism-based biomarkers requires development of easy-to-use, robust and cost-effective tools for secure diagnosis and monitoring of treatment efficacy. Ultimately, matching redox-directed pharmacological interventions to individual patient phenotypes using predictive biomarkers may offer new opportunities to break the therapeutic ceiling in IBD.

Anti-inflammatory and Immunomodulatory Potency of Selenium-Enriched Probiotic Mutants in Mice with Induced Ulcerative Colitis

Selenium-enriched Lactobacillus plantarum and Bifidobacterium longum mutants were used as a protector against Piroxicam-induced ulcerative colitis (UC). In this study, 32 BALB/c male mice were distributed to four groups: the control group, the Piroxicam group which was given 0.8 mg Piroxicam, SP and SB groups which were given 0.8 mg Piroxicam, and plus Lactobacillus plantarum and Bifidobacterium longum selenium-enriched mutants, respectively. Bodyweight; serum content of IgG, IgM, TNF-α, IL-2, IL-6, and IL-10; CBC; myeloperoxidase enzyme activity; histopathological examination of colon and spleen; and expression of TNF-α, IL-2, IL-6, and IL-10 genes in colon and spleen with qRT-PCR were determined. Bodyweight was found to reduce in the Piroxicam group and then recovery in the SB group. Serum content of IgG, IL-2, and IL-10 reduced in the Piroxicam group, whereas IgG, TNF-α, and IL-6 increased in the Piroxicam group in comparison to the other groups. Myeloperoxidase activity witnessed a significant increase in the Piroxicam group compared with the other groups. No significant differences were observed between all groups in measurements of red cells, hemoglobin, neutrophil, monocyte, eosinophil, and basophil in blood. Meanwhile, the white blood cells and platelets recorded the highest and lowest value, respectively, in the Piroxicam group. The colon of the Piroxicam group showed a noticeably massive infiltration of inflammatory cells in the lamina propria. These inflammations were mildly reduced in the SP group, while the reduction in the SB group was significant. In the Piroxicam group, splenic parenchyma saw an increase in the number of melanomacrophages, while hypertrophic plasma cells were observed in the SP group. The spleen of the SB group exhibits a nearly normal form. TNF-α and IL-6 genes had significantly upregulated in the colon of the Piroxicam group compared to the control group, while they were significantly downregulated in the SB group. In contrast, IL-2 and IL-10 genes had upregulated in the colon of the SB group compared to the control groups, while they had downregulated in the Piroxicam group. The expression of these genes had not recorded significant differences between all groups in the spleen. Therefore, this study recommends Bifidobacterium longum selenium-enriched mutants as anti-inflammatory and immunomodulatory supplements.

FDA-Approved Excipient N, N-Dimethylacetamide Attenuates Inflammatory Bowel Disease in In Vitro and In Vivo Models

Inflammatory bowel disease (IBD) affects almost 7 million people worldwide and is increasing in incidence. While the precise pathogenesis of IBD remains unknown, the production of inflammatory cytokines and chemokines play a central role. We have previously found that N, N-dimethylacetamide (DMA), a widely used non-toxic drug excipient, suppresses cytokine and chemokine secretion in vitro and prevents inflammation-induced preterm birth in vivo. Using sandwich enzyme-linked immunosorbent assays (ELISAs), we tested whether DMA attenuates cytokine and chemokine secretion from LPS- or TNFα-stimulated human intestinal epithelial cells and human monocytes and HMGB1 release from RAW 264.7 cells. To test our hypothesis that the mechanism of DMA's effects in in vitro and in vivo models of IBD is inhibition of the NF-κB pathway, we used western blotting to track levels of the nuclear factor kappa B (NF-κB) inhibitory molecule I kappa B alpha (IκBα) in THP-1 human monocytes in the absence or presence of DMA. Finally, we induced colitis in C57Bl/6 mice with dextran sodium sulfate (DSS) and then tested whether i.p injections of DMA at 2.1 g/kg/day attenuates clinical and histopathologic signs of colitis. DMA attenuated cytokine and chemokine release from human intestinal epithelial cells and human monocytes and HMGB1 release from RAW 264.7 cells. Importantly, DMA prevented degradation of IκBα in THP-1 cells, thereby suggesting one mechanism for DMA's effects. Finally, we show here, for the first time, that DMA attenuates clinical and histologic features of DSS-induced colitis. Based on these data, DMA should be further explored in preclinical and clinical trials for its potential as novel drug therapy for IBD.

Gly-Pro-Ala peptide and FGSHF3 exert protective effects in DON-induced toxicity and intestinal damage via decreasing oxidative stress

Deoxynivalenol (DON), a common mycotoxin, usually induces oxidative stress and intestinal injury of humans and animals. This study aims to investigate the protective effect of Gly-Pro-Ala (GPA) peptide, isolated from fish skin gelatin hydrolysate fraction 3 (FGSHF3), on alleviating the toxicity and oxidative stress induced by DON in the mice and IPEC-J2 cells. DON treatment decreases average daily gain and feeds intake, which causes enlargement of the liver and spleen. FGSHF3 (200 mg/kg) and GPA (200 mg/kg) treatment significantly increase average daily gain and inhibits enlargement of the liver and spleen. Furthermore, FGSHF3 and GPA treatment significantly alleviates intestinal injury and maintains tight junction in mice and IPEC-J2 cells. FGSHF3 and GPA treatment significantly inhibits ROS and MDA production and enhances antioxidant enzyme activity, such as CAT, SOD-1, GCLM, GCLC, and GSH-PX. Furthermore, FGSHF3 and GPA treatment promote Nrf2 migration from the cytoplasm to the nucleus, resulting in exerting antioxidant effects. And its effects are abolished after Nrf2 is knockdown by siRNA. Overall, our results suggest GPA peptide may be a promising candidate for the alleviation of DON-induced toxicity in humans and animals.

IL-1 and CD40/CD40L platelet complex: elements of induction of Crohn's disease and new therapeutic targets

Ulcerative colitis (UC) and Crohn's disease (CD) are chronic and multifactorial diseases that affect the intestinal tract, both characterized by recurrent inflammation of the intestinal mucosa, resulting in abdominal pain, diarrhea, vomiting and, rectal bleeding. Inflammatory bowel diseases (IBD) regroup these two disorders. The exact pathological mechanism of IBD remains ambiguous and poorly known. In genetically predisposed patients, defects in intestinal mucosal barrier are due to an uncontrolled inflammatory response to normal flora. In addition to the genetic predisposition, these defects could be triggered by environmental factors or by a specific lifestyle which is widely accepted as etiological hypothesis. The involvement of the CD40/CD40L platelet complex in the development of IBD has been overwhelmingly demonstrated. CD40L is climacteric in cell signalling in innate and adaptive immunity, the CD40L expression on the platelet cell surface gives them an immunological competence. The IL-1, a major inflammation mediator could be involved in different ways in the development of IBD. Here, we provide a comprehensive review regarding the role of platelet CD40/CD40L in the pathophysiological effect of IL-1 in the development of Crohn's disease (CD). This review could potentially help future approaches aiming to target these two pathways for therapeutic purposes and elucidate the immunological mechanisms driving gut inflammation.

High-Fat Diet Promotes DSS-Induced Ulcerative Colitis by Downregulated FXR Expression through the TGFB Pathway

Ulcerative colitis is one of the IBD which cause a chronic intestinal inflammation and dysfunctional of the mucosal barrier. For now, the incident of UC was steadily increased all over the world. It has become a novel independent risk factor of several severe diseases especially colon-rectal cancer. However, the etiology of UC was still obscure. Previous studies show that high-fat diet contributed to the pathogenesis of immune system dysregulation, and farnesoid X receptor (FXR) was also implicated in the pathogenesis of various inflammatory symptoms. Yet, their inner roles in the pathogenesis of UC have not been mentioned. In this study, we aim to investigate the role of FXR in UC. High-fat diet (HFD) promotes the progression of DSS-induced UC, shows an increasing secretion of bile acid in serum, and leads to a downregulation of FXR target genes (FXRα, Shp, and lbabp). Adding FXR agonist FexD rescues the phenotype induced by high-fat diet, whereas TGFBRI inhibitor SB431542 abrogates the restoration by FexD in DSS-induced UC mice. To further verify the relationship between the FXR and TGFB signaling pathway, we made a UC-HFD model in the Caco2 cell line. Results shows the same conclusion that FXR mitigate UC inflammation through a TGFB-dependent pathway. These results expand the role of FXR in ulcerative colitis and suggest that FXR activation may be considered a therapeutic strategy for UC.

Oxidative Stress and Redox-Modulating Therapeutics in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is associated with the production of reactive species that target cysteine redox switches in proteins, thereby affecting gene regulation, DNA damage, ion transport, intermediary metabolism, and mitochondrial function. Precursors of reactive species are derived from organic and inorganic compounds and their cofactors, including amino acids, vitamins, oxygen, nitrite, and sulfate. Nutrition and the gut microbiome fuel this process to a significant extent. The production of reactive species in IBD is reflected by a reduction in systemic free thiols, the major components of the antioxidant machinery. Systemic free thiols are amenable to nutritional or therapeutic intervention. This opens up future avenues for therapeutic modulation of redox status in IBD.

Colorectal Surgery Review for Primary Care Providers

Colon and rectal disorders can be functional and inflammatory. This is the second paper of a three-part series14 and will focus on the diagnosis and treatment of rectal prolapse, fecal incontinence and inflammatory bowel disease.

Assessing Mucosal Inflammation in a DSS-Induced Colitis Mouse Model by MR Colonography

Inflammatory bowel disease (IBD) is characterized by a chronic flaring inflammation of the gastrointestinal tract. To determine disease activity, the inflammatory state of the colon should be assessed. Endoscopy in patients with IBD aids visualization of mucosal inflammation. However, because the mucosa is fragile, there is a significant risk of perforation. In addition, the technique is based on grading of the entire colon, which is highly operator-dependent. An improved, noninvasive, objective magnetic resonance imaging (MRI) technique will effectively assess pathologies in the small intestinal mucosa, more specifically, along the colon, and the bowel wall and surrounding structures. Here, dextran sodium sulfate polymer induced acute colitis in mice that was subsequently characterized by multisection magnetic resonance colonography. This study aimed to develop a noninvasive, objective, quantitative MRI technique for detecting mucosal inflammation in a dextran sodium sulfate–induced colitis mouse model. MRI results were correlated with endoscopic and histopathological evaluations.

Cryptotanshinone inhibits prostaglandin E2 production and COX-2 expression via suppression of TLR4/NF-κB signaling pathway in LPS-stimulated Caco-2 cells

Crytotanshinone (CTN), one of the main constituents of Salvia miltiorrhiza, has been known to exhibit antioxdative, anti-inflammatory and other important therapeutic activities. The aim of this study was to evaluate the effect of CTN on prostaglandin E2 and COX-2 production in LPS-stimulated human intestinal cells (Caco-2 cells). Caco-2 cells were stimulated with LPS in the presence or absence of CTN. The production of prostaglandin E2 (PGE₂) was detected by ELISA. The expression of COX-2 was detected by qRT-PCR and Western blot. The extent of phosphorylation of IκB-α, NF-κB p65 and the expression of TLR4 were detected by western blot. The results showed that CTN dose-dependently inhibited the expression of COX-2 both in mRNA and protein levels, resulting in a decreased production of PGE₂. We also found that CTN suppressed LPS-induced NF-κB activation and IκBα degradation. Furthermore, CTN inhibited the expression of TLR4 up-regulated by LPS. These results suggest that CTN exerts an anti-inflammatory property by inhibiting TLR4/NF-κB signaling pathway and the release of pro-inflammatory mediators. These findings suggest that CTN may be a therapeutic agent against intestinal inflammatory diseases.

Protective effects of polyphenol-rich infusions from carob (Ceratonia siliqua) leaves and cladodes of Opuntia ficus-indica against inflammation associated with diet-induced obesity and DSS-induced colitis in Swiss mice

In the present study, we have investigated the effects of polyphenol-rich infusions from carob leaves and OFI-cladodes on inflammation associated with obesity and dextran sulfate sodium (DSS)-induced ulcerative colitis in Swiss mice. In vitro studies revealed that aqueous extracts of carob leaves and OFI-cladodes exhibited anti-inflammatory properties marked by the inhibition of IL-6, TNF-α and nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells concomitant with NF-κβ nucleus translocation inhibition. For in vivo investigations, Swiss male mice were subjected to control or high fat diet (HFD). At the 8th week after the start of study, animals received or not 1% infusion of either carob leaves or OFI-cladode for 4 weeks and were subjected to 2% DSS administration in drinking water over last 7 days. After sacrifice, pro-inflammatory cytokines levels in plasma and their mRNA expression in different organs were determined. Results showed that carob leaf and OFI-cladode infusions reduced inflammation severity associated with HFD-induced obesity and DSS-induced acute colitis indicated by decrease in pro-inflammatory cytokines expression (as such TNF-α, IL1b and IL-6) in colon, adipose tissue and spleen. In addition, plasma levels of IL-6 and TNF-α were also curtailed in response to infusions treatment. Thus, carob leaf and OFI-cladode infusions prevented intestinal permeability through the restoration of tight junction proteins (Zo1, occludins) and immune homeostasis. Hence, the anti-inflammatory effect of carob leaves and OFI-cladodes could be attributed to their polyphenols which might alleviate inflammation severity associated with obesity and colitis.

Anti-inflammatory effect of a novel locally acting A2A receptor agonist in a rat model of oxazolone-induced colitis

Adenosine represents a powerful modulating factor, which has been shown to orchestrate the scope, duration, and remission of the inflammatory response through the activation of four specific receptors, classified as A₁, A_2A, A_2B, and A₃, all being widely expressed in a variety of immune cells. Several selective A_2A receptor agonists have displayed anti-inflammatory effects, through the suppression of IL-12, TNF, and IFN-γ production by monocytes and lymphocytes, in the setting of chronic intestinal inflammation. However, the therapeutic application of A_2A receptor agonists remains hindered by the risk of serious cardiovascular adverse effects arising from the wide systemic distribution of A_2A receptors. The present study focused on evaluating the anti-inflammatory effects of the novel poorly absorbed A_2A receptor agonist PSB-0777 in a rat model of oxazolone-induced colitis as well as to evaluate its cardiovascular adverse effects, paying particular attention to the onset of hypotension, one of the main adverse effects associated with the systemic pharmacological activation of A_2A receptors. Colitis was associated with decreased body weight, an enhanced microscopic damage score and increased levels of colonic myeloperoxidase (MPO). PSB-0777, but not dexamethasone, improved body weight. PSB-0777 and dexamethasone ameliorated microscopic indexes of inflammation and reduced MPO levels. The beneficial effects of PSB-0777 on inflammatory parameters were prevented by the pharmacological blockade of A_2A receptors. No adverse cardiovascular events were observed upon PSB-0777 administration. The novel A_2A receptor agonist PSB-0777 could represent the base for the development of innovative pharmacological entities able to act in an event-specific and site-specific manner.

Signalling mechanisms in PAF-induced intestinal failure

Capillary leakage syndrome, vasomotor disturbances and gut atony are common clinical problems in intensive care medicine. Various inflammatory mediators and signalling pathways are involved in these pathophysiological alterations among them platelet-activating factor (PAF). The related signalling mechanisms of the PAF-induced dysfunctions are only poorly understood. Here we used the model of the isolated perfused rat small intestine to analyse the role of calcium (using calcium deprivation, IP-receptor blockade (2-APB)), cAMP (PDE-inhibition plus AC activator), myosin light chain kinase (inhibitor ML-7) and Rho-kinase (inhibitor Y27632) in the following PAF-induced malfunctions: vasoconstriction, capillary and mucosal leakage, oedema formation, malabsorption and atony. Among these, the PAF-induced vasoconstriction and hyperpermeability appear to be governed by similar mechanisms that involve IP3 receptors, extracellular calcium and the Rho-kinase. Our findings further suggest that cAMP-elevating treatments - while effective against hypertension and oedema - bear the risk of dysmotility and reduced nutrient uptake. Agents such as 2-APB or Y27632, on the other hand, showed no negative side effects and improved most of the PAF-induced malfunctions suggesting that their therapeutic usefulness should be explored.

The potential of volatile organic compounds for the detection of active disease in patients with ulcerative colitis

BACKGROUND

To optimise treatment of ulcerative colitis (UC), patients need repeated assessment of mucosal inflammation. Current non-invasive biomarkers and clinical activity indices do not accurately reflect disease activity in all patients and cannot discriminate UC from non-UC colitis. Volatile organic compounds (VOCs) in exhaled air could be predictive of active disease or remission in Crohn's disease.

AIM

To investigate whether VOCs are able to differentiate between active UC, UC in remission and non-UC colitis.

METHODS

UC patients participated in a 1-year study. Clinical activity index, blood, faecal and breath samples were collected at each out-patient visit. Patients with clear defined active faecal calprotectin >250 μg/g and inactive disease (Simple Clinical Colitis Activity Index <3, C-reactive protein <5 mg/L and faecal calprotectin <100 μg/g) were included for cross-sectional analysis. Non-UC colitis was confirmed by stool culture or radiological evaluation. Breath samples were analysed by gas chromatography time-of-flight mass spectrometry and kernel-based method to identify discriminating VOCs.

RESULTS

In total, 72 UC (132 breath samples; 62 active; 70 remission) and 22 non-UC-colitis patients (22 samples) were included. Eleven VOCs predicted active vs. inactive UC in an independent internal validation set with 92% sensitivity and 77% specificity (AUC 0.94). Non-UC colitis patients could be clearly separated from active and inactive UC patients with principal component analysis.

CONCLUSIONS

Volatile organic compounds can accurately distinguish active disease from remission in UC and profiles in UC are clearly different from profiles in non-UC colitis patients. VOCs have demonstrated potential as new non-invasive biomarker to monitor inflammation in UC.

Alterations in cytokine gene expression profile in colon mucosa of Inflammatory Bowel Disease patients on different therapeutic regimens

Inflammatory bowel disease (IBD) is assumed to be caused by genetic and environmental factors that interact together in promoting intestinal immune dysregulation where cytokines have validated role. However, the underlying intimate mechanisms in the human IBD involving cytokines still needs to be supplemented especially in the clinical context. The aim of this study was to investigate the expression of some inflammatory and regulatory cytokines (IL-17A, IL-23, IL-6, TGFβ1, and IL-10) as well as of the transcription factor FoxP3 in mucosal samples of IBD and non-IBD patients. We assessed the mRNA relative quantities (RQ) of the above-mentioned cytokines and the transcription factor FoxP3 in paired colonic samples (inflamed and adjacent normal mucosa) from 37 patients with IBD and in normal mucosal tissue in 12 persons without IBD by performing a qRT-PCR assay and tested the protein levels of target cytokines in serum samples. The patients were divided into three groups: without any therapy (n=10), on 5-ASA (n=11) and on immunosuppressants (Azathioprine±5-ASA/corticosteroids) (n=16) in order to compare the RQ values for each therapeutic group. All investigated genes were found upregulated in the inflamed mucosa of IBD patients in the following order: IL-6>FoxP3>TGFβ1>IL-23>IL-17A>IL-10. We also observed that the gene expression of FoxP3 and IL-6 were substantially higher in the inflamed mucosal tissue of the IBD patients than the adjacent normal mucosa (p=0.035, p=0.03 respectively). Differences between higher mRNA expression of FoxP3 and IL-6 in inflamed tissue were considered significant in patients with ulcerative colitis (UC) (p=0.011, p=0.000 respectively) and with Crohn's disease (CD) (p=0.008, p=0.000 respectively) in comparison to the normal mucosa of non-IBD persons and we found increased TGFβ1 in CD patients alone (p=0.041). Furthermore, IL-6 and TGFβ1 were overexpressed (RQ>10) in non-inflamed mucosa from IBD patients compared to the normal mucosa from the controls. When we compared the gene expression for paired mucosa in the immunosuppressive treated group with the 5-ASA treated group we observed opposite changes in IL-6 and TGFβ1 expression. Additionally, we found higher serum levels of IL-23 (p=0.008), TGFβ1 and IL-6 in IBD patients compared to non-IBD patients. The obtained specific expression profile consisting of IL-6, TGFβ1, IL-10 and FoxP3 may represent a transcriptional hallmark for IBD. Furthermore, we found that treatment with immunosuppressive therapy was more beneficial for driving cytokine expression to restore immune regulation in patients with IBD, unlike the 5-ASA therapy.

Recent Trends in Pharmacological Activity of Alkaloids in Animal Colitis: Potential Use for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic and disrupted inflammation of the gastrointestinal tract. IBD have two main conditions, Crohn's disease and ulcerative colitis, and have been extensively investigated in recent years. Antibiotics derived from salicylates, steroids, immunosuppressors, and anti-TNF therapy are part of the therapeutic arsenal for IBD. However, very often patients stop responding to treatments over the time. In this context, searching for alternative agents is crucial for IBD clinical management. Natural products derived from medicinal plants are an interesting therapeutic alternative, since several studies have proven effective treatments in animal models of intestinal inflammation. Several naturally occurring compounds are potent antioxidants, both as free radical scavengers and as modulators of antioxidant enzymes expression and activity. A number of natural compounds have also been proved to inhibit the release of proinflammatory cytokines, decreasing the activation of nuclear factor κB (NF-κB), which is important to the inflammatory response in IBD. The alkaloids are substances of a very diverse class of plant secondary metabolites; an extensive list of biological activities has been attributed to alkaloids, such as being anticholinergic, antitumor, diuretic, antiviral, antihypertensive, antiulcer, analgesic, and anti-inflammatory. In the present work, studies on the pharmacological activity of alkaloids in experimental models of IBD were reviewed.

The Immunological Basis of Inflammatory Bowel Disease

Inflammatory bowel diseases (IBDs) are chronic ailments, Crohn's disease and ulcerative colitis being the most important. These diseases present an inflammatory profile and they differ according to pathophysiology, the affected area in the gastrointestinal tract, and the depth of the inflammation in the intestinal wall. The immune characteristics of IBD arise from abnormal responses of the innate and adaptive immune system. The number of Th17 cells increases in the peripheral blood of IBD patients, while Treg cells decrease, suggesting that the Th17/Treg proportion plays an important role in the development and maintenance of inflammation. The purpose of this review was to determine the current state of knowledge on the immunological basis of IBD. Many studies have shown the need for further explanation of the development and maintenance of the inflammatory process.

Dynamic collection and analysis of volatile organic compounds from the headspace of cell cultures

Exhaled breath has proven to be a valuable source of information about human bodies. Subtle differences between volatile organic compounds (VOCs) formed endogenously can be detected and become a base for a potential monitoring tool for health and disease. Until now, there has been a lack of biological and mechanistic knowledge of the processes involved in the production of relevant VOCs. Among the possible sources of health-related and disease-related VOCs are microorganisms found in the respiratory tract and in the gut. Other VOCs in the body are produced by cells that are influenced by the disease, for instance, due to metabolic disorders and/or inflammation. To gain insight into the in vivo production of VOCs by human cells and thus the exhaled breath composition, in vitro experiments involving relevant cells should be studied because they may provide valuable information on the production of VOCs by the affected cells. To this aim we developed and validated a system for dynamically (continuously) collecting headspace air in vitro using a Caco-2 cell line. The system allows the application of different cell lines as well as different experimental setups, including varying exposure times and treatment options while preserving cell viability. Significant correlation (p  ⩽  0.0001) between collection outputs within each studied group confirmed high reproducibility of the collection system. An example of such an application is presented here. We studied the influence of oxidative stress on the VOC composition of the headspace air of Caco-2 cells. By comparing the VOC composition of air flushed through empty culture flasks (n  =  35), flasks with culture medium (n  =  35), flasks with medium and cells (n  =  20), flasks with medium and an oxidative stressor (H2O2) (n  =  20), and flasks with medium, stressor, and cells (n  =  20), we were able to separate the effects from the stressor on the cells from all other interactions. Measurements were performed with gas chromatography time-of-flight mass spectrometry. Multivariate data analysis allowed detection of significant altered compounds in the compared groups. We found a significant change (p  ⩽  0.001) of the composition of VOCs due to the stressing of the Caco-2 cells by H2O2. A total of ten VOCs showed either increased or decreased abundance in the headspace of the cell cultures due to the presence of the H2O2 stressor.

Oxidative Stress and DNA Damage: Implications in Inflammatory Bowel Disease

This review will focus on published human studies on oxidative stress and DNA damage in inflammatory bowel disease (IBD), both ulcerative colitis and Crohn's disease, assessing their role in the pathophysiology of these diseases. Search was performed over PubMed and ScienceDirect databases to identify relevant bibliography, using keywords including "oxidative stress," "DNA damage," "IBD," and "oxidative DNA damage." Whether as cause or effect, mechanisms underlying oxidative stress have the potential to condition the course of various pathologies, particularly those driven by inflammatory scenarios. IBDs are chronic inflammatory relapsing conditions. Oxidative stress has been associated with some of the characteristic clinical features exhibited in IBD, namely tissue injury and fibrosis, and also to the ulcerative colitis-associated colorectal cancer. The possible influence of oxidative stress over therapeutic behavior and response, as well as their contribution to the oxidative burden and consequences, is also addressed. Due to the high prevalence and incidence of IBD worldwide, and also to its associated morbidity, complications, and disease and treatment costs, it is of paramount importance to better understand the pathophysiology of these diseases.

Inflammatory Bowel Disease: An Overview of Immune Mechanisms and Biological Treatments

Inflammatory bowel diseases (IBD) are characterized by chronic inflammation of the intestinal tract associated with an imbalance of the intestinal microbiota. Crohn's disease (CD) and ulcerative colitis (UC) are the most widely known types of IBD and have been the focus of attention due to their increasing incidence. Recent studies have pointed out genes associated with IBD susceptibility that, together with environment factors, may contribute to the outcome of the disease. In ulcerative colitis, there are several therapies available, depending on the stage of the disease. Aminosalicylates, corticosteroids, and cyclosporine are used to treat mild, moderate, and severe disease, respectively. In Crohn's disease, drug choices are dependent on both location and behavior of the disease. Nowadays, advances in treatments for IBD have included biological therapies, based mainly on monoclonal antibodies or fusion proteins, such as anti-TNF drugs. Notwithstanding the high cost involved, these biological therapies show a high index of remission, enabling a significant reduction in cases of surgery and hospitalization. Furthermore, migration inhibitors and new cytokine blockers are also a promising alternative for treating patients with IBD. In this review, an analysis of literature data on biological treatments for IBD is approached, with the main focus on therapies based on emerging recombinant biomolecules.

Volatile Organic Compounds in Exhaled Air as Novel Marker for Disease Activity in Crohn's Disease: A Metabolomic Approach

BACKGROUND

Disappearance of macroscopic mucosal inflammation predicts long-term outcome in Crohn's disease (CD). It can be assessed by ileocolonoscopy, which is, however, an invasive and expensive procedure. Disease activity indices do not correlate well with endoscopic activity and noninvasive markers have a low sensitivity in subgroups of patients. Volatile organic compounds (VOCs) in breath are of increasing interest as noninvasive markers. The aim of this study was to investigate whether VOCs can accurately differentiate between active CD and remission.

METHODS

Patients participated in a 1-year follow-up study and Harvey-Bradshaw index, blood, fecal, and breath samples were collected at regular intervals. Patients were stratified into 2 groups: active (fecal calprotectin >250 µg/g) or inactive (Harvey-Bradshaw index <4, C-reactive protein <5 mg/L, and fecal calprotectin <100 µg/g) disease. Breath samples were analyzed by gas chromatography-time-of-flight mass spectrometry. Random forest analyses were used to find the most discriminatory VOCs.

RESULTS

Eight hundred thirty-five breath-o-grams were measured, 140 samples were assigned as active, 135 as inactive disease, and 110 samples of healthy controls. A set of 10 discriminatory VOCs correctly predicted active CD in 81.5% and remission in 86.4% (sensitivity 0.81, specificity 0.80, AUC 0.80). These VOCs were combined into a single disease activity score that classified disease activity in more than 60% of the previously undetermined individuals.

CONCLUSIONS

We showed that VOCs can separate healthy controls and patients with active CD and CD in remission in a real-life cohort. Analysis of exhaled air is an interesting new noninvasive application for monitoring mucosal inflammation in inflammatory bowel disease.

Umbilical cord mesenchymal stem cells modulate dextran sulfate sodium induced acute colitis in immunodeficient mice

Introduction

Inflammatory bowel diseases (IBD) are complex multi-factorial diseases with increasing incidence worldwide but their treatment is far from satisfactory. Unconventional strategies have consequently been investigated, proposing the use of cells as an effective alternative approach to IBD. In the present study we examined the protective potential of exogenously administered human umbilical cord derived mesenchymal stem cells (UCMSCs) against Dextran Sulfate Sodium (DSS) induced acute colitis in immunodeficient NOD.CB₁₇-Prkdc^scid/J mice with particular attention to endoplasmic reticulum (ER) stress.

Methods

UCMSCs were injected in NOD.CB₁₇-Prkdc^scid/J via the tail vein at day 1 and 4 after DSS administration. To verify attenuation of DSS induced damage by UCMSCs, Disease Activity Index (DAI) and body weight changes was monitored daily. Moreover, colon length, histological changes, myeloperoxidase and catalase activities, metalloproteinase (MMP) 2 and 9 expression and endoplasmic reticulum (ER) stress related proteins were evaluated on day 7.

Results

UCMSCs administration to immunodeficient NOD.CB₁₇-Prkdc^scid/J mice after DSS damage significantly reduced DAI (1.45 ± 0.16 vs 2.08 ± 0.18, p < 0.05), attenuating the presence of bloody stools, weight loss, colon shortening (8.95 ± 0.33 cm vs 6.8 ± 0.20 cm, p < 0.01) and histological score (1.97 ± 0.13 vs 3.27 ± 0.13, p < 0.001). Decrease in neutrophil infiltration was evident from lower MPO levels (78.2 ± 9.7 vs 168.9 ± 18.2 U/g, p < 0.01). DSS treatment enhanced MMP2 and MMP9 activities (>3-fold), which were significantly reduced in mice receiving UCMSCs. Moreover, positive modulation in ER stress related proteins was observed after UCMSCs administration.

Conclusions

Our results demonstrated that UCMSCs are able to prevent DSS-induced colitis in immunodeficient mice. Using these mice we demonstrated that our UCMSCs have a direct preventive effect other than the T-cell immunomodulatory properties which are already known. Moreover we demonstrated a key function of MMPs and ER stress in the establishment of colitis suggesting them to be potential therapeutic targets in IBD treatment.

IBD: microbiota manipulation through diet and modified bacteria

BACKGROUND/AIMS

Crohn's disease (CD) and ulcerative colitis (UC) are both typified by an altered intestinal microbiota, and gene associations imply various defects in the mucosal barrier and in the innate immune response to bacteria. This review aims to assess how alterations in diet or use of modified bacteria could have therapeutic effects in CD or UC.

METHODS

A MEDLINE search using the terms 'prebiotic', 'genetically modified bacteria', 'mucosal barrier in association with ulcerative colitis', 'Crohn's disease' or 'microbiota'.

RESULTS

A large body of data from in vitro and animal studies shows promise for therapeutic approaches that target the microbiota. Approaches include dietary supplementation with fermentable fibres (prebiotics) and soluble fibres that block bacterial-epithelial adherence (contrabiotics), enhancement of the mucosal barrier with phosphatidylcholine, and use of genetically modified bacteria that express IL-10 or protease inhibitors. Vitamin D supplementation also shows promise, acting via enhancement of innate immunity. Clinical trials have shown benefit with enterically delivered phosphatidylcholine supplementation in UC and near-significant benefit with vitamin D supplementation in CD.

CONCLUSION

Strategies that target the microbiota or the host defence against it appear to be good prospects for therapy and deserve greater investment.

Hydrolysate from eggshell membrane ameliorates intestinal inflammation in mice

Inflammatory bowel diseases (IBD) comprises of ulcerative colitis (UC) and Cohn’s disease (CD) as two main idiopathic pathologies resulting in immunologically mediated chronic inflammatory conditions. Several bioactive peptides and hydro lysates from natural sources have now been tested in animal models of human diseases for potential anti-inflammatory effects. Eggshell membrane (ESM) is a well-known natural bioactive material. In this study, we aim to study the anti-inflammatory activity of ESM hydro lysate (AL-PS) in vitro and in vivo. In vitro, AL-PS was shown to inhibit pro-inflammatory cytokine IL-8 secretion. In vivo treatment with AL-PS was shown to reduce dextran sodium sulphate (DSS)-induced weight loss, clinical signs of colitis and secretion of interleukin (IL)-6 (p < 0.05). In addition, treatment with AL-PS also attenuated the severity of intestinal inflammation via down-regulation of IL-10 an anti-inflammatory cytokine. This validates potential benefits of AL-PS as a novel preventative target molecule for treatment of IBD.

Endometrial regenerative cells as a novel cell therapy attenuate experimental colitis in mice

Background

Endometrial regenerative cells (ERCs) are mesenchymal-like stem cells that can be non-invasively obtained from menstrual blood and are easily grown /generated at a large scale without tumorigenesis. We previously reported that ERCs exhibit unique immunoregulatory properties in vitro, however their immunosuppressive potential in protecting the colon from colitis has not been investigated. The present study was undertaken to determine the efficacy of ERCs in mediating immunomodulatory functions against colitis.

Methods

Colitis was induced by 4% dextran-sulfate-sodium (DSS, in drinking water) in BALB/c mice for 7 days. ERCs were cultured from healthy female menstrual blood, and injected (1 million/mouse/day, i.v.) into mice on days 2, 5, and 8 following colitis induction. Colonic and splenic tissues were collected on day 14 post-DSS-induction. Clinical signs, disease activity index (DAI), pathological and immunohistological changes, cytokine profiles and cell populations were evaluated.

Results

DSS-induced mice in untreated group developed severe colitis, characterized by body-weight loss, bloody stool, diarrhea, mucosal ulceration and colon shortening, as well as pathological changes of intra-colon cell infiltrations of neutrophils and Mac-1 positive cells. Notably, ERCs attenuated colitis with significantly reduced DAI, decreased levels of intra-colon IL-2 and TNF-α, but increased expressions of IL-4 and IL-10. Compared with those of untreated colitis mice, splenic dendritic cells isolated from ERC-treated mice exhibited significantly decreased MHC-II expression. ERC-treated mice also demonstrated much less CD3⁺CD25⁺ active T cell and CD3⁺CD8⁺ T cell population and significantly higher level of CD4⁺CD25⁺Foxp3⁺ Treg cells.

Conclusions

This study demonstrated novel anti-inflammatory and immunosuppressive effects of ERCs in attenuating colitis in mice, and suggested that the unique features of ERCs make them a promising therapeutic tool for the treatment of ulcerative colitis.

Association of the macrophage migration inhibitory factor gene--173G/C polymorphism with inflammatory bowel disease: a meta-analysis of 4296 subjects

A variety of epidemiologic studies have focused on the association between macrophage migration inhibitory factor (MIF) gene--173G/C polymorphism and inflammatory bowel disease (IBD). However, results in different studies have been inconsistent. In order to derive a more precise estimation of the associations, we performed this meta-analysis and systematic searches of electronic databases PubMed and Web of Science (up to April 30, 2013). Based on our search criteria, a total of seven eligible studies concerning the MIF--173G/C polymorphism and IBD risk were included in the final meta-analysis, comprising 2162 IBD cases and 2134 controls. Significant association was found between MIF--173G/C polymorphism and the risk of IBD when all studies were pooled into the meta-analysis (for C allele vs. G allele: OR=1.25, 95% CI=1.12-1.41, p=0.000; for C/C vs. G/G: OR=1.71, 95% CI=1.23-2.39, p=0.002; for C/C+G/C vs. G/G: OR=1.24, 95% CI=1.09-1.42, p=0.002; for C/C vs. G/C+G/G: OR=1.67, 95% CI=1.20-2.33, p=0.002). Heterogeneity and publication bias did not exist in the overall comparisons. The present meta-analysis suggests an association between the MIF--173G/C polymorphism and IBD risk. However, due to few studies and the selection bias existed in some studies, the results should be interpreted with caution.

Nitrite and nitrite reductases: from molecular mechanisms to significance in human health and disease

Nitrite, previously considered physiologically irrelevant and a simple end product of endogenous nitric oxide (NO) metabolism, is now envisaged as a reservoir of NO to be activated in response to oxygen (O(2)) depletion. In the first part of this review, we summarize and compare the mechanisms of nitrite-dependent production of NO in selected bacteria and in eukaryotes. Bacterial nitrite reductases, which are copper or heme-containing enzymes, play an important role in the adaptation of pathogens to O(2) limitation and enable microrganisms to survive in the human body. In mammals, reduction of nitrite to NO under hypoxic conditions is carried out in tissues and blood by an array of metalloproteins, including heme-containing proteins and molybdenum enzymes. In humans, tissues play a more important role in nitrite reduction, not only because most tissues produce more NO than blood, but also because deoxyhemoglobin efficiently scavenges NO in blood. In the second part of the review, we outline the significance of nitrite in human health and disease and describe the recent advances and pitfalls of nitrite-based therapy, with special attention to its application in cardiovascular disorders, inflammation, and anti-bacterial defence. It can be concluded that nitrite (as well as nitrate-rich diet for long-term applications) may hold promise as therapeutic agent in vascular dysfunction and ischemic injury, as well as an effective compound able to promote angiogenesis.

The PepT1-transportable soy tripeptide VPY reduces intestinal inflammation

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract. The peptide transporter PepT1 is responsible for the intestinal uptake of dietary peptides, and its expression in the gastrointestinal tract is up-regulated during intestinal inflammation, indicating that PepT1 may be a promising target for IBD therapeutics.

METHODS

The transport of soy-derived di- and tripeptides across Caco-2 intestinal epithelial cells was examined, and the anti-inflammatory effects of the transported peptide VPY were evaluated in vitro in Caco-2 and THP-1 macrophages, and in vivo in a mouse model of DSS-induced colitis.

RESULTS

VPY inhibited the secretion of IL-8 and TNF-α, respectively, from Caco-2 and THP-1 cells. VPY transport and anti-inflammatory activity in Caco-2 cells was reduced in the presence of Gly-Sar, indicating this activity was mediated by PepT1. In mice, VPY treatment reduced DSS-induced colitis symptoms and weight loss, improved colon histology, reduced MPO activity, and decreased gene expression of the pro-inflammatory cytokines TNF-α, IL-6, IL-1β, IFN-γ and IL-17 in the colon.

CONCLUSIONS AND GENERAL SIGNIFICANCE

VPY is a novel PepT1 substrate that can inhibit the production of pro-inflammatory mediators in vitro in intestinal epithelial and immune cells, and reduce the severity of colitis in mice by down-regulating the expression of pro-inflammatory cytokines in the colon, suggesting that VPY may be promising for the treatment of IBD.

Modulation of NF-κB activation by resveratrol in LPS treated human intestinal cells results in downregulation of PGE2 production and COX-2 expression

Resveratrol is a natural phytoalexin present in a variety of plant species, such as grapes and red wine, that is well known for its anti-inflammatory effects. In addition, a cancer chemotherapeutic activity of resveratrol has been described. Here we evaluated the effect of resveratrol on COX-2 and prostaglandin E(2) production in human intestinal cells Caco-2 cells treated with lipopolysaccharide (LPS). Resveratrol concentration-dependently inhibited the expression of COX-2 mRNA in the LPS-treated cells, as well as protein expression, resulting in a decreased production of PGE(2). In order to investigate the mechanisms through which resveratrol exhibited these anti-inflammatory effects, we examined the activation of IκB in LPS-stimulated intestinal cells. Results demonstrated that resveratrol inhibited the translocation of NF-κB p65 subunits from the cytosol to the nucleus, which correlated with its inhibitory effects on IκBα phosphorylation and degradation. These results suggest that the down-regulation of COX-2 and PGE(2) by resveratrol may be related to NF-κB inhibition through the negative regulation of IKK phosphorylation in intestinal cells.

Immunologic and genetic markers in patients with idiopathic ocular inflammation and a family history of inflammatory bowel disease

PURPOSE

To evaluate the prevalence of immunologic and genetic markers in patients with idiopathic ocular inflammation and a family history of inflammatory bowel disease.

DESIGN

Matched case-control study.

METHODS

Patients with a diagnosis of idiopathic ocular inflammation and family history of inflammatory bowel disease who did not have inflammatory bowel disease themselves were identified and matched to control patients with idiopathic ocular inflammation. Serum was evaluated for immunologic markers using Prometheus IBD Serology 7. Genomic DNA was analyzed for single nucleotide polymorphisms (SNP) of the NOD2 gene associated with Crohn disease.

RESULTS

Fifteen patients with idiopathic ocular inflammation and family history of inflammatory bowel disease were matched to 15 control patients based on age, sex, and race. Eight of 15 patients (53%) with a family history of inflammatory bowel disease had elevated p-ANCA antibody levels compared to 3 of 15 controls (20%) (1-sided P = .04) with a matched analysis odds ratio of 6.0 (1-sided P = .06). Four of 15 patients (27%) with family history of inflammatory bowel disease tested positive for immunologic markers predicting ulcerative colitis, while no control patients tested positive (1-sided P = .06). Carrier rates of NOD2 SNPs did not differ significantly between the test and control groups.

CONCLUSIONS

One-quarter of patients with idiopathic ocular inflammation and a family history of inflammatory bowel disease had immunologic markers predicting bowel disease, and one-half had elevated p-ANCA levels. Prometheus IBD Serology 7 may be useful in the evaluation of selected patients with unexplained uveitis.

A functional polymorphism in UGT1A1 related to hyperbilirubinemia is associated with a decreased risk for Crohn's disease

BACKGROUND

An imbalance between the production of reactive oxygen species (ROS) and their capturing by antioxidants results in oxidative stress, this may play an important role in the pathogenesis of inflammatory bowel disease (IBD). Since bilirubin is an important endogenous antioxidant, increased levels of bilirubin may protect against IBD. UDP-glucuronosyltransferase 1A1 (UGT1A1) is the only enzyme involved in the conjugation of bilirubin and the common UGT1A1*28 allele in the UGT1A1 gene, which is strongly associated with Gilbert's syndrome in Caucasians, results in elevated plasma bilirubin levels.

AIMS

To test the hypothesis that the UGT1A1*28 allele is associated with lower disease susceptibility to, and disease behavior within, IBD. In addition, a possible altered risk for developing IBD-drug related side-effects was explored.

METHODOLOGY

Genomic DNA of 751 patients with IBD (209 patients with ulcerative colitis and 542 patients with Crohn's disease) and 930 healthy controls was genotyped for the UGT1A1*28 promoter polymorphism, and genotype distribution was compared between patients and controls. Genotype phenotype interactions were also investigated.

RESULTS

Patients with Crohn's disease significantly less often bear the UGT1A1*28 homozygous genotype compared to the control group, with an odds ratio of 0.64, 95% CI: 0.42-0.98. The ulcerative colitis group showed no significant differences compared to controls.

CONCLUSION

The homozygous state of the UGT1A1*28 polymorphism, associated with higher serum bilirubin levels, may be protective for the development of Crohn's disease, suggesting that the anti-oxidant capacity of bilirubin may play a part.

Effects of a dietary intervention on acute gastrointestinal side effects and other aspects of health-related quality of life: a randomized controlled trial in prostate cancer patients undergoing radiotherapy

PURPOSE

To study the effect of a dietary intervention on acute gastrointestinal side effects and other aspects of health-related quality of life (HRQOL) in prostate cancer patients referred to radiotherapy.

MATERIALS AND METHODS

A total of 130 patients were randomly assigned to one of two groups: an intervention group (IG, n=64), instructed to reduce their intake of insoluble dietary fibres and lactose, a standard care group (SC, n=66), instructed to continue their normal diet. Gastrointestinal side effects and other aspects of HRQOL were evaluated from baseline up to 2 months after completed radiotherapy, using the EORTC QLQ-C30 and QLQ-PR25 and the study-specific Gastrointestinal Side Effects Questionnaire (GISEQ). A scale indicating adherence to dietary instructions was developed from a Food Frequency Questionnaire (FFQ), with lower scores representing better compliance. Descriptive and inferential statistical analyses were conducted.

RESULTS

There was an interaction effect between randomization and time in the FFQ Scores (p<0.001), indicating that both groups followed their assigned dietary instructions. The dietary intervention had no effect on gastrointestinal side effects or other aspects of HRQOL. During radiotherapy, the percentage of patients with bowel symptoms and bloated abdomen was lower in IG compared to SC, but the between-group differences were not statistically significant. During radiotherapy, the percentage of patients with bowel symptoms, urinary symptoms, pain, fatigue and diminished physical and role functioning increased in both groups.

CONCLUSIONS

The dietary intervention had no effect on gastrointestinal side effects or other aspects of HRQOL. The tendency towards lower prevalence of bowel symptoms in IG may indicate some positive effect of the dietary intervention, but methodological refinements, clearer results and longer follow-up are needed before the value of diet change can be established with certainty.

Candidate mucosal and surrogate biomarkers of inflammatory bowel disease in the era of new technology

OBJECTIVE

There is increasing knowledge of the pathophysiology behind inflammatory bowel disease (IBD) although the exact mechanism is far from fully understood. In the era of new technology, over the last years molecular approaches have shed light on the inflammatory mechanisms and their metabolic end products. This opens for a molecular fingerprinting that can be used in the biomarker field of IBD. There is a great need of biomarkers for prediction of clinical outcome and prognostic biomarker for prediction of therapeutic effects in IBD. Although the biomarker concept is old, so far very few really useful biomarkers exist in IBD.

MATERIAL AND METHODS

Here, we review the predictive and prognostic biomarkers in IBD in the era of new technologies with emphasis on the potential of molecular fingerprinting.

RESULTS

Very few candidate biomarkers have been documented. The most promising candidate predictor is tumor necrosis factor-α, but there is a lack of validation.

CONCLUSION

So far, there are few biomarkers documented in IBD, but we are at the start of a new scientific field that will be of great value for the handling of the disease.

Effects of feeding potato pulp on cholesterol metabolism and its association with cecal conditions in rats

To clarify the functional properties of potato pulp (PP), a waste product resulting from extraction of starch from potatoes, we examined the effects of PP on cholesterol metabolism and cecal conditions in rats. Plasma total cholesterol (T-Chol) levels were lower in rats fed a PP-supplemented diet for four weeks than in those fed a control diet. Cecal pH was lowered due to an increase in the levels of cecal total short-chain fatty acids, especially butyrate, in the PP group compared to the control group. Furthermore, animals fed with the PP-supplemented diet showed increased cecal ratios of Lactobacillus and Clostridia and decreased cecal ratios of Bacteroides and Gammaproteobacteria with slightly negative and positive correlations with plasma T-Chol levels, respectively. In conclusion, ingestion of PP for four weeks is likely to improve both cecal conditions and cholesterol metabolism, suggesting that PP has prebiotic effects.

Antioxidative potential of a combined therapy of anti TNFα and Zn acetate in experimental colitis

AIM: To evaluate whether combination therapy with anti-tumour necrosis factor α (TNFα) antibody and Zn acetate is beneficial in dextran sodium sulphate (DSS) colitis.

METHODS: Colitis was induced in CD1-Swiss mice with 5% DSS for 7 d. The experimental mice were then randomised into the following subgroups: standard diet + DSS treated (induced colitis group); standard diet + DSS + subcutaneous 25 μg anti-TNFα treated group; Zn acetate treated group + DSS + subcutaneous 25 μg anti-TNFα; standard diet + DSS + subcutaneous 6.25 μg anti-TNFα treated group and Zn acetate treated group + DSS + subcutaneous 6.25 μg anti-TNFα. Each group of mice was matched with a similar group of sham control animals. Macroscopic and histological features were scored blindly. Homogenates of the colonic mucosa were assessed for myeloperoxidase activity as a biochemical marker of inflammation and DNA adducts (8OH-dG) as a measure of oxidative damage.

RESULTS: DSS produced submucosal erosions, ulcers, inflammatory cell infiltration and cryptic abscesses which were reduced in both groups of mice receiving either anti-TNFα alone or combined with zinc. The effect was more pronounced in the latter group (vs Zn diet, P < 0.02). Myeloperoxidase activity (vs controls, P < 0.02) and DNA adducts, greatly elevated in the DSS fed colitis group (vs controls, P < 0.05), were significantly reduced in the treated groups, with a more remarkable effect in the group receiving combined therapy (vs standard diet, P < 0.04).

CONCLUSION: DSS induces colonic inflammation which is modulated by the administration of anti-TNFα. Combining anti-TNFα with Zn acetate offers marginal benefit in colitis severity.

Nutritional stimulation of the autonomic nervous system

Disturbance of the inflammatory response in the gut is important in several clinical diseases ranging from inflammatory bowel disease to postoperative ileus. Several feedback mechanisms exist that control the inflammatory cascade and avoid collateral damage. In the gastrointestinal tract, it is of particular importance to control the immune response to maintain the balance that allows dietary uptake and utilization of nutrients on one hand, while preventing invasion of bacteria and toxins on the other hand. The process of digestion and absorption of nutrients requires a relative hyporesponsiveness of the immune cells in the gut to luminal contents which is not yet fully understood. Recently, the autonomic nervous system has been identified as an important pathway to control local and systemic inflammation and gut barrier integrity. Activation of the pathway is possible via electrical or via pharmacological interventions, but is also achieved in a physiological manner by ingestion of dietary lipids. Administration of dietary lipids has been shown to be very effective in reducing the inflammatory cascade and maintaining intestinal barrier integrity in several experimental studies. This beneficial effect of nutrition on the inflammatory response and intestinal barrier integrity opens new therapeutic opportunities for treatment of certain gastrointestinal disorders. Furthermore, this neural feedback mechanism provides more insight in the relative hyporesponsiveness of the immune cells in the gut. Here, we will discuss the regulatory function of the autonomic nervous system on the inflammatory response and gut barrier function and the potential benefit in a clinical setting.

Inorganic nitrite therapy: historical perspective and future directions

Over the past several years, investigators studying nitric oxide (NO) biology and metabolism have come to learn that the one-electron oxidation product of NO, nitrite anion, serves as a unique player in modulating tissue NO bioavailability. Numerous studies have examined how this oxidized metabolite of NO can act as a salvage pathway for maintaining NO equivalents through multiple reduction mechanisms in permissive tissue environments. Moreover, it is now clear that nitrite anion production and distribution throughout the body can act in an endocrine manner to augment NO bioavailability, which is important for physiological and pathological processes. These discoveries have led to renewed hope and efforts for an effective NO-based therapeutic agent through the unique action of sodium nitrite as an NO prodrug. More recent studies also indicate that sodium nitrate may also increase plasma nitrite levels via the enterosalivary circulatory system resulting in nitrate reduction to nitrite by microorganisms found within the oral cavity. In this review, we discuss the importance of nitrite anion in several disease models along with an appraisal of sodium nitrite therapy in the clinic, potential caveats of such clinical uses, and future possibilities for nitrite-based therapies.

Apple polyphenols require T cells to ameliorate dextran sulfate sodium-induced colitis and dampen proinflammatory cytokine expression

Human IBD, including UC and Crohn's disease, is characterized by a chronic, relapsing, and remitting condition that exhibits various features of immunological inflammation and affects at least one/1000 people in Western countries. Polyphenol extracts from a variety of plants have been shown to have immunomodulatory and anti-inflammatory effects. In this study, treatment with APP was investigated to ameliorate chemically induced colitis. Oral but not peritoneal administration of APP during colitis induction significantly protected C57BL/6 mice against disease, as evidenced by the lack of weight loss, colonic inflammation, and shortening of the colon. APP administration dampened the mRNA expression of IL-1β, TNF-α, IL-6, IL-17, IL-22, CXCL9, CXCL10, CXCL11, and IFN-γ in the colons of mice with colitis. APP-mediated protection requires T cells, as protection was abated in Rag-1(-/-) or TCRα(-/-) mice but not in IL-10(-/-), IRF-1(-/-), μMT, or TCRδ(-/-) mice. Administration of APP during colitis to TCRα(-/-) mice actually enhanced proinflammatory cytokine expression, further demonstrating a requirement for TCRαβ cells in APP-mediated protection. APP treatment also inhibited CXCR3 expression by TCRαβ cells, but not B or NK cells, in the colons of mice with colitis; however, depletion of CD4(+) or CD8(+) T cells alone did not abolish APP-mediated protection. Collectively, these results show that oral administration of APP protects against experimental colitis and diminishes proinflammatory cytokine expression via T cells.

Novel components of the human metabolome: the identification, characterization and anti-inflammatory activity of two 5-androstene tetrols

Two natural 5-androstene steroid tetrols, androst-5-ene-3β,7β,16α,17β-tetrol (HE3177) and androst-5-ene-3α,7β,16α,17β-tetrol (HE3413), were discovered in human plasma and urine. These compounds had significant aqueous solubility, did not bind or transactivate steroid-binding nuclear hormone receptors, and were not immunosuppressive in murine mixed-lymphocyte studies. Both compounds appear to be metabolic end products, as they were resistant to primary and secondary metabolism. Both were orally bioavailable, and were very well tolerated in a two-week dose-intensive toxicity study in mice. Anti-inflammatory properties were found with exogenous administration of these compounds in rodent disease models of multiple sclerosis, lung injury, chronic prostatitis, and colitis.

Preventive oral treatment with resveratrol pro-prodrugs drastically reduce colon inflammation in rodents

There is no pharmaceutical or definitive surgical cure for inflammatory bowel diseases (IBDs). The naturally occurring polyphenol resveratrol exerts anti-inflammatory properties. However, its rapid metabolism diminishes its effectiveness in the colon. The design of prodrugs to targeting active molecules to the colon provides an opportunity for therapy of IBDs. Herein we explore the efficacy of different resveratrol prodrugs and pro-prodrugs to ameliorate colon inflammation in the murine dextran sulfate sodium (DSS) model. Mice fed with a very low dose (equivalent to 10 mg for a 70 kg-person) of either resveratrol-3-O-(6'-O-butanoyl)-β-D-glucopyranoside (6) or resveratrol-3-O-(6'-O-octanoyl)-β-D-glucopyranoside (7) did not develop colitis symptoms and improved 6-fold the disease activity index (DAI) compared to resveratrol. Our results indicate that these pro-prodrugs exerted a dual effect: (1) they prevented the rapid metabolism of resveratrol and delivered higher quantities of resveratrol to the colon and (2) they reduced mucosal barrier imbalance and prevented diarrhea, which consequently facilitated the action of the delivered resveratrol in the colon mucosa.

Role of EP4 receptor and prostaglandin transporter in prostaglandin E2-induced alteration in colonic epithelial barrier integrity

Prostaglandin E(2) (PGE(2)) is a proinflammatory lipid mediator produced in excess in inflammatory bowel disease (IBD). PGE(2) couples to and signals via four different E-prostanoid (EP) receptors, namely EP1, EP2, EP3, and EP4. In this study, we determined a role for PGE(2) and EP4 receptors in altering colonic epithelial barrier integrity. In healthy colonic mucosa, EP4 receptors were localized on apical plasma membrane of epithelial cells at the tip of mucosal folds, whereas, in patients with IBD and in rats with dextran sodium sulfate (DSS)-induced colitis, they were diffusely overexpressed throughout the mucosa. Similarly, expression of EP4 receptor was polarized in T84 colonic epithelial monolayer and mimics the normal epithelium. Apical exposure of T84 monolayer with high levels of PGE(2) decreased barrier integrity, which was abrogated by an EP4 receptor antagonist. To reveal the mechanism of vectorial transport of basally produced PGE(2) toward apical EP4 receptors, we identified prostaglandin transporters (PGT) in human colonic epithelia. PGT were least expressed on epithelial cells at the colonic mucosal folds of control subjects but overexpressed in epithelial cells of patients with IBD or animals with DSS-induced colitis. T84 monolayer also expressed PGT, which increased twofold following stimulation with TNF-α. Importantly, in T84 monolayer stimulated with TNF-α, there was a corresponding increase in the uptake and vectorial transport of (3)H-PGE(2) to the apical surface. Knockdown or pharmacological inhibition of PGT significantly decreased vectorial transport of (3)H-PGE(2). These studies unravel a mechanism whereby EP4 receptor and PGT play a role in PGE(2)-induced alteration of epithelial barrier integrity in colitis.

CD34 is required for infiltration of eosinophils into the colon and pathology associated with DSS-induced ulcerative colitis

Eosinophil migration into the gut and the release of granular mediators plays a critical role in the pathogenesis of inflammatory bowel diseases, including ulcerative colitis. We recently demonstrated that eosinophil migration into the lung requires cell surface expression of the sialomucin CD34 on mast cells and eosinophils in an asthma model. Based on these findings, we investigated a similar role for CD34 in the migration of eosinophils and other inflammatory cells into the colon as well as explored the effects of CD34 ablation on disease development in a dextran sulfate sodium-induced model of ulcerative colitis. Our findings demonstrate decreased disease severity in dextran sulfate sodium-treated Cd34(-/-) mice, as assessed by weight loss, diarrhea, bleeding, colon shortening and tissue pathology, compared with wild-type controls. CD34 was predominantly expressed on eosinophils within inflamed colon tissues, and Cd34(-/-) animals exhibited drastically reduced colon eosinophil infiltration. Using chimeric animals, we demonstrated that decreased disease pathology resulted from loss of CD34 from bone marrow-derived cells and that eosinophilia in Cd34(-/-)IL5(Tg) animals was sufficient to overcome protection from disease. In addition, we demonstrated a decrease in peripheral blood eosinophil numbers following dextran sulfate sodium treatment. These findings demonstrate that CD34 was expressed on colon-infiltrating eosinophils and played a role in eosinophil migration. Further, our findings suggest CD34 is required for efficient eosinophil migration, but not proliferation or expansion, in the development of ulcerative colitis.