Prostaglandin biology in inflammatory bowel disease

Roles of prostaglandins in immunosuppression

Prostaglandins (PGs) play a crucial and multifaceted role in various physiological processes such as intercellular signaling, inflammation regulation, neurotransmission, vasodilation, vasoconstriction, and reproductive functions. The diversity and biological significance of these effects are contingent upon the specific types or subtypes of PGs, with each PG playing a crucial role in distinct physiological and pathological processes. Particularly within the immune system, PGs are essential in modulating the function of immune cells and the magnitude and orientation of immune responses. Hence, a comprehensive comprehension of the functions PG signaling pathways in immunosuppressive regulation holds substantial clinical relevance for disease prevention and treatment strategies. The manuscript provides a review of recent developments in PG signaling in immunosuppressive regulation. Furthermore, the potential clinical applications of PGs in immunosuppression are also discussed. While research into the immunosuppressive effects of PGs required further exploration, targeted therapies against their immunosuppressive pathways might open new avenues for disease prevention and treatment.

Perioperative use of NSAIDs and the risk of short-term endoscopic recurrence in Crohn's disease patients: A retrospective cohort study

BACKGROUND

More evidence is needed on the use of NSAID based postoperative pain regimens for Crohn's disease (CD) and its association with recurrence. Our goal is to assess the impact of perioperative use of NSAIDs on endoscopic disease recurrence in patients with CD.

METHODS

A retrospective cohort study was conducted. The primary outcome measured was endoscopic disease recurrence within 24 months of surgery, defined as a Rutgeerts score ≥ i2.

RESULTS

We identified 107 patients with CD that underwent index ileocolectomy with primary anastomosis between January 2009 and July 2019. Endoscopic disease recurrence was identified in 28 (26.2%) and clinical recurrence in 18 (16.8%) patients. Exposure to NSAIDs did not increase 24-month endoscopic recurrence risk (22.2% vs. 38.5% patients, p = 0.12).

CONCLUSION

In patients with CD undergoing elective ileocolic resection and primary ileocolic anastomosis, NSAID use in the perioperative period did not impact endoscopic or clinical disease recurrence rate.

Integrated bioinformatics and network pharmacology to identify the therapeutic target and molecular mechanisms of Huangqin decoction on ulcerative Colitis

Huangqin decoction (HQD) is a Traditional Chinese Medicine formula for ulcerative colitis. However, the pharmacology and molecular mechanism of HQD on ulcerative colitis is still unclear. Combined microarray analysis, network pharmacology, and molecular docking for revealing the therapeutic targets and molecular mechanism of HQD against ulcerative colitis. TCMSP, DrugBank, Swiss Target Prediction were utilized to search the active components and effective targets of HQD. Ulcerative colitis effective targets were obtained by microarray data from the GEO database (GSE107499). Co-targets between HQD and ulcerative colitis are obtained by Draw Venn Diagram. PPI (Protein–protein interaction) network was constructed by the STRING database. To obtain the core target, topological analysis is exploited by Cytoscape 3.7.2. GO and KEGG enrichment pathway analysis was performed to Metascape platform, and molecular docking through Autodock Vina 1.1.2 finished. 161 active components with 486 effective targets of HQD were screened. 1542 ulcerative colitis effective targets were obtained with |Log₂FC|> 1 and adjusted P-value < 0.05. The Venn analysis was contained 79 co-targets. Enrichment analysis showed that HQD played a role in TNF signaling pathway, IL-17 signaling pathway, Th17 cell differentiation, etc. IL6, TNF, IL1B, PTGS2, ESR1, and PPARG with the highest degree from PPI network were successfully docked with 19 core components of HQD, respectively. According to ZINC15 database, quercetin (ZINC4175638), baicalein (ZINC3871633), and wogonin (ZINC899093) recognized as key compounds of HQD on ulcerative colitis. PTGS2, ESR1, and PPARG are potential therapeutic targets of HQD. HQD can act on multiple targets through multi-pathway, to carry out its therapeutic role in ulcerative colitis.

Specific Secondary Bile Acids Control Chicken Necrotic Enteritis

Necrotic enteritis (NE), mainly induced by the pathogens of Clostridium perfringens and coccidia, causes huge economic losses with limited intervention options in the poultry industry. This study investigated the role of specific bile acids on NE development. Day-old broiler chicks were assigned to six groups: noninfected, NE, and NE with four bile diets of 0.32% chicken bile, 0.15% commercial ox bile, 0.15% lithocholic acid (LCA), or 0.15% deoxycholic acid (DCA). The birds were infected with Eimeria maxima at day 18 and C. perfringens at day 23 and 24. The infected birds developed clinical NE signs. The NE birds suffered severe ileitis with villus blunting, crypt hyperplasia, epithelial line disintegration, and massive immune cell infiltration, while DCA and LCA prevented the ileitis histopathology. NE induced severe body weight gain (BWG) loss, while only DCA prevented NE-induced BWG loss. Notably, DCA reduced the NE-induced inflammatory response and the colonization and invasion of C. perfringens compared to NE birds. Consistently, NE reduced the total bile acids in the ileal digesta, while dietary DCA and commercial bile restored it. Together, this study showed that DCA and LCA reduced NE histopathology, suggesting that secondary bile acids, but not total bile acid levels, play an essential role in controlling the enteritis.

(E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone isolated from Portulaca oleracea L. suppresses LPS-induced inflammation in RAW 264.7 macrophages by downregulating inflammatory factors

CONTEXT

Portulaca oleracea L. is herbaceous succulent annual plant, which belongs to the Portulacaceae family. Many studies have shown its wide spectrum of pharmacological activities such as anti-cancer and anti-diabetic effects.

OBJECTIVES

The objective of this study was to identify the anti-inflammatory effects of HM-chromanone isolated from Portulaca oleracea L. in LPS-stimulated RAW 264.7 macrophages.

MATERIALS AND METHODS

LPS (1 μg/ml)-stimulated mouse RAW 264.7 macrophages were used to assess the anti-inflammatory effect of HM-chromanone (10-50 μM). Cell viability was evaluated by MTT assay. In addition, the production of intracellular ROS, superoxide anion, lipid peroxide, NO, and PGE2, and activity of antioxidant enzymes were analyzed. The expressions of iNOS, COX-2, IκB, NF-κB, TNF-α, IL-1β and IL-6 were evaluated by western blot analysis.

RESULTS

HM-chromanone has demonstrated that there is no significant cytotoxic effect on the viability of RAW 264.7 macrophages. In LPS-stimulated RAW 264.7 cells, HM-chromanone treatment was found to significantly inhibit the production of intracellular ROS, superoxide anion and lipid peroxide, while enhancing the activity of antioxidant enzymes such as SOD, catalase, and GSH-px. Additionally, HM-chromanone treatment was observed to inhibit NO and PGE2 production by inhibiting the expression of iNOS and COX-2. Subsequently, HM-chromanone was observed to significantly suppress LPS-induced expression of IκB, NF-κB, TNF-α, IL-1β and IL-6.

DISCUSSION AND CONCLUSION

Overall, our results suggested that HM-chromanone suppresses LPS-induced inflammation in RAW 264.7 macrophages by downregulating the expression of inflammatory factors.

Oral administration of Jumihaidokuto inhibits UVB-induced skin damage and prostaglandin E2 production in HR-1 hairless mice

This study was conducted to investigate whether and how Jumihaidokuto (JHT), a traditional Chinese medicine, prevents UVB-induced skin damage in male HR-1 hairless mice. JHT has been traditionally prescribed for patients presenting skin disorders with redness and swelling, and, in Japan, it is approved for prescription to patients with acute and/or purulent skin disorders, hives, acute eczema, and athlete's foot. Considering the traditional use of JHT, we hypothesized that oral administration of JHT might emerge as an effective strategy to prevent UVB-induced skin damage, such as edema and erythema. Here, we pretreated mice with JHT (1000 mg/kg, p.o.) for 3 weeks and then administered a single dose of UVB irradiation (250 mJ/cm²) on the dorsal skin. UVB irradiation increased the erythema index and transepidermal water loss (TEWL) and decreased the skin water content in the epidermis at 72 h post-irradiation. JHT treatment inhibited the increase of TEWL and the loss of water content in the epidermis, but not the elevation of the erythema index. Moreover, administration of JHT suppressed UVB-induced epidermal hyperplasia by blocking the proliferation of keratinocytes and also inhibited irradiation-triggered reduction of collagen fibers and infiltration of immune cells into the dermis. Lastly, administration of JHT suppressed UVB-induced production of proinflammatory mediators, such as prostaglandin E2 and interleukin-1β. These results suggest that JHT prevents UVB-induced skin damage and that the underlying mechanism involves the inhibition of proinflammatory mediators.

IBD considerations in spondyloarthritis

Spondyloarthritis (SpA) may be regarded a family of auto-inflammatory conditions with inflammation focused on the joints. These form part of a wider family of immune-mediated inflammatory diseases, which include inflammatory bowel diseases (IBD). These conditions share common elements of pathophysiology and it is perhaps unsurprising, therefore, that individuals with SpA frequently manifest gastrointestinal inflammation, to which the physician managing the patient with SpA must be alert. In this article, we review the shared epidemiology and pathophysiology of these conditions, before discussing approaches to diagnosis and management of inflammatory gastrointestinal pathology in patients seen in rheumatology clinics. In particular, we discuss the difference between non-specific gastrointestinal inflammation commonly described in this patient group and the more specific diagnosis of Crohn's disease or ulcerative colitis. We describe the appropriate diagnostic workup for patients suspected of having IBD. In addition, we discuss how a diagnosis of IBD can inform treatment selection, highlighting important differences in treatment choice, drug dosing, monitoring and drug safety for this particular comorbid patient population.

Exploration of anti-inflammatory mechanism of forsythiaside A and forsythiaside B in CuSO4-induced inflammation in zebrafish by metabolomic and proteomic analyses

BACKGROUND

Inflammation is a general pathological phenomenon during severe disturbances to the homeostasis. Forsythiaside A (FA) and forsythiaside B (FB), isolated from the dried fruit of Forsythia suspensa (Thunb.) Vahl, are phenylethanoid compounds that show a significant anti-inflammatory effect. However, the properties and therapeutic mechanisms of this effect have not yet been systematically elucidated.

METHODS

In this study, the anti-inflammatory effects of FA and FB were investigated in CuSO₄-induced inflammation in zebrafish larvae. Intracellular generation of reactive oxygen species (ROS) and nitric oxide (NO) was investigated using fluorescence probes. Metabolomic and proteomic analyses using liquid chromatography-mass spectrometry were carried out to identify the expressions of metabolites and proteins associated with the anti-inflammatory mechanism of FA and FB. Quantitative polymerase chain reaction (PCR) was performed to detect the progressive changes in gene expression.

RESULTS

FA and FB inhibited neutrophils migration to the damaged neuromasts and remarkably reduced CuSO₄-induced ROS and NO generation in zebrafish larvae. Metabolomic analysis pointed to the involvement of nicotinate and nicotinamide metabolism, energy metabolism, pyrimidine metabolism, and purine metabolism. Proteomic analysis identified 146 differentially expressed proteins between the control and model groups. These included collagen [collagen type II alpha 1b precursor (col2a1b), collagen alpha-2(IX) chain precursor (col9a2), collagen type IX alpha I precursor (col9a1b)], nucleoside diphosphate kinase 3 isoform X1 (Nme3), WD repeat-containing protein 3 (Wdr3), and 28S ribosomal protein S7 mitochondrial precursor (Mrps7). FA and FB were shown to reverse the abnormal expressions of potential metabolite and protein biomarkers and alleviate CuSO₄-induced damage to the neuromasts in the zebrafish lateral line.

CONCLUSIONS

Our results indicate that FA and FB possess remarkable anti-inflammatory properties, protecting against CuSO₄-induced neuromasts damage in zebrafish larvae. The results also suggest a multi-component and multi-regulatory therapeutic mechanism for FA and FB.

Primary hypertrophic osteoarthropathy related gastrointestinal complication has distinctive clinical and pathological characteristics: two cases report and review of the literature

BACKGROUND

Primary hypertrophic osteoarthropathy (PHO) is a rare disease related to HPGD and SLCO2A1 gene mutation. Gastrointestinal involvement of PHO is even rarer with unknown pathogenesis. Clinical features of GI complication in PHO mimics other auto-immune based bowel entities, such as inflammatory bowel diseases and cryptogenic multifocal ulcerous stenosing enteritis (CMUSE). We aimed to analyze the clinical, genetic, radiological and pathological features of Chinese patients with PHO and determine the difference between PHO patients presenting with and without GI involvement.

METHODS

We reported two PHO cases with gastrointestinal involvement and reviewed all the studies of PHO in Chinese population published from January 1, 2000, to April 30, 2018. Clinical and genetic presentations of PHO in Chinese patients were analyzed. We compared the characteristics of those patients with gastrointestinal involvement against those without.

RESULTS

The two patients were both males with complete-form PHO for more than 10 years. GI related symptoms included diarrhea, chronic gastrointestinal hemorrhage, incomplete intestinal obstruction, anemia, and edema, which were unresponsive to etoricoxib treatment. Radiological examinations revealed segmental intestinal stenosis and thickened intestinal wall. Endoscopic findings included multiple ulcers and mucosal inflammation. Both patients had mutations of SLCO2A1 according to sequence analysis. The surgical pathology revealed chronic inflammation involving the intestinal mucosa and submucosa, similar to histological changes in CMUSE. According to the systemic review of 158 Chinese patients with PHO, 17.2% had gastrointestinal involvement, including peptic ulcer, gastric polyps, hypertrophic gastritis, and segmental intestinal stenosis. Patients with gastrointestinal involvement were more likely to have anemia (40.0% vs. 4.5%, P < 0.001), hypoalbuminemia (16.7% vs. 0.9%, P = 0.003), and myelofibrosis (19.0% vs. 0.9%, P = 0.002) than those without. Most patients with gastrointestinal complication had SLCO2A1 mutation (86.7%, 13 /15).

CONCLUSIONS

Digestive tract involvement is uncommon in patients with PHO and often presents with anemia, and hypoalbuminemia resulted from intestinal inflammation. The intestinal pathologic characteristics are distinct from Crohn's disease but similar to CMUSE. Mutations in SLCO2A1 might be the pathogenic cause of GI involvement of PHO. NSAIDs may not be effective for PHO patients with gastrointestinal complications.

Mechanisms for Reducing Neuropathic Pain

Injury typically results in the development of neuropathic pain, but the pain normally decreases and disappears in paralleled with wound healing. The pain results from cells resident at, and recruited to, the injury site releasing pro-inflammatory cytokines and other mediators leading to the development of pro-inflammatory environment and causing nociceptive neurons to develop chronic ectopic electrical activity, which underlies neuropathic pain. The pain decreases as some of the cells that induce pro-inflammation, changing their phenotype leading to the blocking the release of pro-inflammatory mediators while releasing anti-inflammatory mediators, and blocking nociceptive neuron chronic spontaneous electrical activity. Often, despite apparent wound healing, the neuropathic pain becomes chronic. This raises the question of how chronic pain can be eliminated. While many of the cells and mediators contributing to the development and maintenance of neuropathic pain are known, a better understanding is required of how the injury site environment can be controlled to permanently eliminate the pro-inflammatory environment and silence the chronically electrically active nociceptive neurons. This paper examines how methods that can promote the transition of the pro-inflammatory injury site to an anti-inflammatory state, by changing the composition of local cell types, modifying the activity of pro- and anti-inflammatory receptors, inducing the release of anti-inflammatory mediators, and silencing the chronically electrically active nociceptive neurons. It also examines the hypothesis that factors released from platelet-rich plasma applied to chronic pain sites can permanently eliminate chronic inflammation and its associated chronic pain.

Microbial metabolite deoxycholic acid controls Clostridium perfringens-induced chicken necrotic enteritis through attenuating inflammatory cyclooxygenase signaling

Necrotic enteritis (NE) caused by Clostridium perfringens infection has reemerged as a prevalent poultry disease worldwide due to reduced usage of prophylactic antibiotics under consumer preferences and regulatory pressures. The lack of alternative antimicrobial strategies to control this disease is mainly due to limited insight into the relationship between NE pathogenesis, microbiome, and host responses. Here we showed that the microbial metabolic byproduct of secondary bile acid deoxycholic acid (DCA), at as low as 50 µM, inhibited 82.8% of C. perfringens growth in Tryptic Soy Broth (P < 0.05). Sequential Eimeria maxima and C. perfringens challenges significantly induced NE, severe intestinal inflammation, and body weight (BW) loss in broiler chickens. These negative effects were diminished (P < 0.05) by 1.5 g/kg DCA diet. At the cellular level, DCA alleviated NE-associated ileal epithelial death and significantly reduced lamina propria cell apoptosis. Interestingly, DCA reduced C. perfringens invasion into ileum (P < 0.05) without altering the bacterial ileal luminal colonization. Molecular analysis showed that DCA significantly reduced inflammatory mediators of Infγ, Litaf, Il1β, and Mmp9 mRNA accumulation in ileal tissue. Mechanism studies revealed that C. perfringens induced (P < 0.05) elevated expression of inflammatory mediators of Infγ, Litaf, and Ptgs2 (Cyclooxygenases-2 (COX-2) gene) in chicken splenocytes. Inhibiting the COX signaling by aspirin significantly attenuated INFγ-induced inflammatory response in the splenocytes. Consistent with the in vitro assay, chickens fed 0.12 g/kg aspirin diet protected the birds against NE-induced BW loss, ileal inflammation, and intestinal cell apoptosis. In conclusion, microbial metabolic product DCA prevents NE-induced BW loss and ileal inflammation through attenuating inflammatory response. These novel findings of microbiome protecting birds against NE provide new options on developing next generation antimicrobial alternatives against NE.

Gut Inflammation in Association With Pathogenesis of Parkinson's Disease

Parkinson’s disease (PD) is a neurodegenerative disease that is generally thought to be caused by multiple factors, including environmental and genetic factors. Emerging evidence suggests that intestinal disturbances, such as constipation, are common non-motor symptoms of PD. Gut inflammation may be closely associated with pathogenesis in PD. This review aims to discuss the cross-talk between gut inflammation and PD pathology initiation and progression. Firstly, we will highlight the studies demonstrating how gut inflammation is related to PD. Secondly, we will analyze how gut inflammation spreads from the gastro-intestine to the brain. Here, we will mainly discuss the neural pathway of pathologic α-syn and the systemic inflammatory routes. Thereafter, we will address how alterations in the brain subsequently lead to dopaminergic neuron degeneration, in which oxidative stress, glutamate excitotoxicity, T cell driven inflammation and cyclooxygenase-2 (COX-2) are involved. We conclude a model of PD triggered by gut inflammation, which provides a new angle to understand the mechanisms of the disease.

Lipid metabolism in inflammation-related diseases

There are thousands of lipid species existing in cells, which belong to eight different categories. Lipids are the essential building blocks of cells. Recent studies have started to unveil the important functions of lipids in regulating cell metabolism. However, we are still at a very early stage in fully understanding the physiological and pathological functions of lipids. The application of lipidomics for studying lipid metabolism can provide a direct readout of the cellular status and broadens our understanding of the mechanisms that underpin metabolic disease states. This review provides an introduction to lipid metabolism and its role in modulating homeostasis and immunity. We also describe representative applications of lipidomics for studying lipid metabolism in inflammation-related diseases.

A Quantitative Analysis of Colonic Mucosal Oxylipins and Endocannabinoids in Treatment-Naïve and Deep Remission Ulcerative Colitis Patients and the Potential Link With Cytokine Gene Expression

BACKGROUND

The bioactive metabolites of omega 3 and omega 6 polyunsaturated fatty acids (ω-3 and ω-6) are known as oxylipins and endocannabinoids (eCBs). These lipid metabolites are involved in prompting and resolving the inflammatory response that leads to the onset of inflammatory bowel disease (IBD). This study aims to quantify these bioactive lipids in the colonic mucosa and to evaluate the potential link to cytokine gene expression during inflammatory events in ulcerative colitis (UC).

METHODS

Colon biopsies were taken from 15 treatment-naïve UC patients, 5 deep remission UC patients, and 10 healthy controls. Thirty-five oxylipins and 11 eCBs were quantified by means of ultra-high-performance liquid chromatography coupled with tandem mass spectrometry. Levels of mRNA for 10 cytokines were measured by reverse transcription polymerase chain reaction.

RESULTS

Levels of ω-6-related oxylipins were significantly elevated in treatment-naïve patients with respect to controls, whereas the levels of ω-3 eCBs were lower. 15S-Hydroxy-eicosatrienoic acid (15S-HETrE) was significantly upregulated in UC deep remission patients compared with controls. All investigated cytokines had significantly higher mRNA levels in the inflamed mucosa of treatment-naïve UC patients. Cytokine gene expression was positively correlated with several ω-6 arachidonic acid-related oxylipins, whereas negative correlation was found with lipoxin, prostacyclin, and the eCBs.

CONCLUSIONS

Increased levels of ω-6-related oxylipins and decreased levels of ω-3-related eCBs are associated with the debut of UC. This highlights the altered balance between pro- and anti-inflammatory lipid mediators in IBD and suggests potential targets for intervention.

Treatment with P28GST, a schistosome-derived enzyme, after acute colitis induction in mice: Decrease of intestinal inflammation associated with a down regulation of Th1/Th17 responses

Background

P28GST, a 28Kd glutathione S-transferase enzymatic protein derived from a schistosome helminth prevents experimental colitis when administered subcutaneously in the presence of adjuvant by decreasing pro-inflammatory Th1/Th17 response. Given the antioxidant properties of P28GST, we evaluated its anti-inflammatory potential when administered locally after colitis induction in the absence of adjuvant.

Methods

Colitis was induced in BALB/c mice by rectal administration of TNBS, followed by two intraperitoneal injections of P28GST at day 1 and day 2. Mice were sacrificed 48h after TNBS administration and evaluated for macroscopic and histological scores, myeloperoxidase (MPO) quantification and cytokine messenger RNA expression in the colonic tissues.

Results

Both clinical and histological scores significantly decreased in mice treated with P28GST at 5 or 50μg/kg when compared to vehicle- treated mice. A significant reduction of MPO was detected in colonic tissues from P28GST–treated mice, similarly to mice treated with methylprednisolone as the reference treatment. Pro-inflammatory cytokines TNF, IL-1β, and IL-6, mRNA as well as serum levels were down-regulated in mice colonic tissues treated with P28GST at 5 or 50μg/kg. In addition, a significant decrease of mRNA expression levels of T-bet, and ROR-γ, respective markers of Th1 and Th17 cells was observed. Whereas no significant effect was detected on Gata3 mRNA, a marker of Th2 cells, the Arg/iNOS mRNA levels significantly increased in P28GST-treated mice, suggesting the induction of M2 macrophages.

Conclusions

These findings provide evidence that P28GST injected locally after colitis induction induces a potent decrease of colitis inflammation in mice, associated to downregulation of Th1/Th17 response, and induction of anti-inflammatory alternatively activated macrophages.

Selected Molecular Mechanisms Involved in the Parasite⁻Host System Hymenolepis diminuta⁻Rattus norvegicus

The rat tapeworm Hymenolepis diminuta is a parasite of the small intestine of rodents (mainly mice and rats), and accidentally humans. It is classified as a non-invasive tapeworm due to the lack of hooks on the tapeworm’s scolex, which could cause mechanical damage to host tissues. However, many studies have shown that metabolites secreted by H. diminuta interfere with the functioning of the host’s gastrointestinal tract, causing an increase in salivary secretion, suppression of gastric acid secretion, and an increase in the trypsin activity in the duodenum chyme. Our work presents the biochemical and molecular mechanisms of a parasite-host interaction, including the influence on ion transport and host intestinal microflora, morphology and biochemical parameters of blood, secretion of antioxidant enzymes, expression of Toll-like receptors, mechanisms of immune response, as well as the expression and activity of cyclooxygenases. We emphasize the interrelations between the parasite and the host at the cellular level resulting from the direct impact of the parasite as well as host defense reactions that lead to changes in the host’s tissues and organs.

Pilot study: duodenal MDR1 and COX2 gene expression in cats with inflammatory bowel disease and low-grade alimentary lymphoma

Objectives Multidrug resistance 1 (MDR1) encodes a protein called P-glycoprotein (P-gp), which serves as an efflux pump membrane protein implicated in intestinal homeostasis and drug resistance. Cyclooxygenase-2 (COX2) is a key enzyme in the synthesis of proinflammatory prostaglandins, tumourigenesis and in mucosal defence. Despite the importance of MDR1 and COX2, changes in their mRNA levels have not been studied in cats with inflammatory bowel disease (IBD) and low-grade alimentary lymphoma (LGAL). The present study aimed to determine the mRNA levels of MDR1 and COX2 in cats with IBD and LGAL, and to evaluate their correlation with clinical signs, histological severity and between genes. Methods Cats diagnosed with IBD (n = 20) and LGAL (n = 9) between 2008 and 2015 were included in the current study. Three healthy animals composed the healthy control cats group in which endoscopy was performed immediately before the ovariohysterectomy. All duodenal biopsy samples were obtained by endoscopy. Feline chronic enteropathy activity index was calculated for all cases. IBD histopathology was classified according to severity. MDR1 and COX2 mRNA levels were determined by absolute reverse transcriptase-quantitative real-time PCR. Results Statistically significant differences were observed for MDR1 and COX2 mRNA levels between the IBD and LGAL groups. No correlations were observed between molecular gene expression, feline chronic enteropathy activity index and histological grading for IBD, and between MDR1 and COX2 genes. However, a positive statistically significant correlation was observed between MDR1 and COX2 expression in the duodenum of cats. Conclusions and relevance MDR1 and COX2 gene expression is increased in cats with LGAL compared with cats with IBD. The control group tended to have lower values than both diseased groups. These results suggest that these genes may be involved in the pathogenesis of IBD or LGAL in cats.

Impaired lipid metabolism markers to assess the risk of neuroinflammation in autism spectrum disorder

Autism spectrum disorder (ASD) is a multifactorial disorder caused by an interaction between environmental risk factors and a genetic background. It is characterized by impairment in communication, social interaction, repetitive behavior, and sensory processing. The etiology of ASD is still not fully understood, and the role of neuroinflammation in autism behaviors needs to be further investigated. The aim of the present study was to test the possible association between prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-1 (mPGES-1), prostaglandin PGE2 EP2 receptors and nuclear kappa B (NF-κB) and the severity of cognitive disorders, social impairment, and sensory dysfunction. PGE2, COX-2, mPGES-1, PGE2-EP2 receptors and NF-κB as biochemical parameters related to neuroinflammation were determined in the plasma of 47 Saudi male patients with ASD, categorized as mild to moderate and severe as indicated by the Childhood Autism Rating Scale (CARS) or the Social Responsiveness Scale (SRS) or the Short Sensory Profile (SSP) and compared to 46 neurotypical controls. The data indicated that ASD patients have remarkably higher levels of the measured parameters compared to neurotypical controls, except for EP2 receptors that showed an opposite trend. While the measured parameter did not correlate with the severity of social and cognitive dysfunction, PGE2, COX-2, and mPGES-1 were remarkably associated with the dysfunction in sensory processing. NF-κB was significantly increased in relation to age. Based on the discussed data, the positive correlation between PGE2, COX-2, and mPGES-1 confirm the role of PGE2 pathway and neuroinflammation in the etiology of ASD, and the possibility of using PGE2, COX-2 and mPGES-1 as biomarkers of autism severity. NF-κB as inflammatory inducer showed an elevated level in plasma of ASD individuals. Receiver operating characteristic analysis together with predictiveness diagrams proved that the measured parameters could be used as predictive biomarkers of biochemical correlates to ASD.

Protective effect of decursin and decursinol angelate-rich Angelica gigas Nakai extract on dextran sulfate sodium-induced murine ulcerative colitis

OBJECTIVE

To investigate the anti-inflammatory effects of decursin and decursinol angelate-rich Angelica gigas Nakai (AGNE) on dextran sulfate sodium (DSS)-induced murine ulcerative colitis (UC).

METHODS

The therapeutic effect of an AGNE was analyzed in a mouse model of UC induced by DSS. Disease activity index values were measured by clinical signs such as a weight loss, stool consistency, rectal bleeding and colon length. A histological analysis was performed using hematoxylin and eosin staining. Key inflammatory cytokines and mediators including IL-6, TNF-α, PGE₂, COX-2 and HIF-1α were assayed by enzyme-linked immunosorbent assay or western blotting.

RESULTS

Treatment with the AGNE at 10, 20, and 40 mg/kg alleviated weight loss, decreased disease activity index scores, and reduced colon shortening in mice with DSS-induced UC. AGNE inhibited the production of IL-6 and TNF-α in serum and colon tissue. Moreover, AGNE suppressed the increased expression of COX-2 and HIF-1α and the increased production of PGE₂ in colon tissue were observed in mice with DSS-induced UC. Additionally, histological damage was also alleviated by AGNE treatment.

CONCLUSIONS

The findings of this study verified that AGNE significantly improves clinical symptoms and reduces the activity of various inflammatory mediators. These results indicate the AGNE has the therapeutic potential in mice with DSS-induced UC.

Biomarkers and Microscopic Colitis: An Unmet Need in Clinical Practice

One of the most common causes of chronic diarrhea is ascribed to microscopic colitis (MC). MC is classified in subtypes: collagenous colitis (CC) and lymphocytic colitis (LC). Patients with MC report watery, non-bloody diarrhea of chronic course, abdominal pain, weight loss, and fatigue that may impair patient's health-related quality of life. A greater awareness, and concomitantly an increasing number of diagnoses over the last years, has demonstrated that the incidence and prevalence of MC are on the rise. To date, colonoscopy with histological analysis on multiple biopsies collected along the colon represents the unique accepted procedure used to assess the diagnosis of active MC and to evaluate the response to medical therapy. Therefore, the emerging need for less-invasive procedures that are also rapid, convenient, standardized, and reproducible, has encouraged scientists to turn their attention to the identification of inflammatory markers and other molecules in blood or feces and within the colonic tissue that can confirm a MC diagnosis. This review gives an update on the biomarkers that are potentially available for the identification of inflammatory activity, related to CC and LC.

Identification of Biomarkers of Impaired Sensory Profiles among Autistic Patients

Background

Autism is a neurodevelopmental disorder that displays significant heterogeneity. Comparison of subgroups within autism, and analyses of selected biomarkers as measure of the variation of the severity of autistic features such as cognitive dysfunction, social interaction impairment, and sensory abnormalities might help in understanding the pathophysiology of autism.

Methods and Participants

In this study, two sets of biomarkers were selected. The first included 7, while the second included 6 biomarkers. For set 1, data were collected from 35 autistic and 38 healthy control participants, while for set 2, data were collected from 29 out of the same 35 autistic and 16 additional healthy subjects. These markers were subjected to a principal components analysis using either covariance or correlation matrices. Moreover, libraries composed of participants categorized into units were constructed. The biomarkers used include, PE (phosphatidyl ethanolamine), PS (phosphatidyl serine), PC (phosphatidyl choline), MAP2K1 (Dual specificity mitogen-activated protein kinase kinase 1), IL-10 (interleukin-10), IL-12, NFκB (nuclear factor-κappa B); PGE2 (prostaglandin E2), PGE2-EP2, mPGES-1 (microsomal prostaglandin synthase E-1), cPLA2 (cytosolic phospholipase A2), 8-isoprostane, and COX-2 (cyclo-oxygenase-2).

Results

While none of the studied markers correlated with CARS and SRS as measure of cognitive and social impairments, six markers significantly correlated with sensory profiles of autistic patients. Multiple regression analysis identifies a combination of PGES, mPGES-1, and PE as best predictors of the degree of sensory profile impairment. Library identification resulted in 100% correct assignments of both autistic and control participants based on either set 1 or 2 biomarkers together with a satisfactory rate of assignments in case of sensory profile impairment using different sets of biomarkers.

Conclusion

The two selected sets of biomarkers were effective to separate autistic from healthy control subjects, demonstarting the possibility to accurately predict the severity of autism using the selected biomarkers. The effectiveness of the identified libraries lied in the fact that they were helpful in correctly assigning the study population as control or autistic patients and in classifying autistic patients with different degree of sensory profile impairment.

Current concepts on microscopic colitis: evidence-based statements and recommendations of the Spanish Microscopic Colitis Group

BACKGROUND

Microscopic colitis (MC) is an underdiagnosed inflammatory bowel disease.

AIM

To develop an evidence-based clinical practice guide on MC current concepts.

METHODS

Literature search was done on the Cochrane Library, EMBASE and MEDLINE electronic databases, which were consulted covering the period up until March 2015. Work groups were selected for each of the reviewed topics, with the purpose of drafting the initial statements and recommendations. They subsequently underwent a voting process based on the Delphi method. Each statement/recommendation was accompanied by the result of the vote the level of evidence, and discussion of the corresponding evidence. The grade of recommendation (GR) using the GRADE approach was established for diagnosis and treatment recommendations.

RESULTS

Some key statements and recommendations are: advancing age increases the risk of developing MC, mainly in females. The symptoms of MC and IBS-D may be similar. If MC is suspected, colonoscopy taking biopsies is mandatory. Treatment with oral budesonide is recommended to induce clinical remission in patients with MC. Oral mesalazine is not recommended in patients with collagenous colitis for the induction of clinical remission. The use of anti-TNF-alpha drugs (infliximab, adalimumab) is recommended for the induction of remission in severe cases of MC that fail to respond to corticosteroids or immunomodulators, as an alternative to colectomy.

CONCLUSIONS

This is the first consensus paper on MC based on GRADE methodology. This initiative may help physicians involved in care of these patients in taking decisions based on evidence.

Cytokine expression of microscopic colitis including interleukin-17

Background/Aims

Microscopic colitis is characterized by chronic watery diarrhea with specific pathological changes that can be diagnosed by microscopic examination. We performed immunohistochemical analysis of proinflammatory cytokines to investigate the pathogenic mechanism of microscopic colitis.

Methods

This study consisted of six patients with lymphocytic colitis, six patients with collagenous colitis, and six patients with functional diarrhea but normal pathology. We performed an immunohistochemical analysis of the colonic mucosal biopsies to assess the expression of cyclo-oxygenase-2, interleukin-17, nuclear factor-κB, interferon-γ, inducible nitric oxide synthase, and tumor necrosis factor-α. We compared the quantity score of immunohistochemical staining among the groups.

Results

The microscopic colitis group showed significantly higher expression of cyclo-oxygenase-2, interleukin-17, nuclear factor-κB, and interferon-γ compared with the control group. Cytokine expression was similar between collagenous colitis and lymphocytic colitis. However, the expression of cyclo-oxygenase-2 was higher in collagenous colitis.

Conclusions

Proinflammatory cytokines, including interleukin-17 and interferon-γ, are highly expressed in microscopic colitis. The expression of cyclo-oxygenase-2 was higher in collagenous colitis than in lymphocytic colitis. This study is the first on interleukin-17 expression in microscopic colitis patients.

Use of Cyclo-Oxygenase Inhibitors Is Not Associated with Clinical Relapse in Inflammatory Bowel Disease: A Case-Control Study

Patients with inflammatory bowel disease (IBD) often have associated conditions, for which anti-inflammatory medication with cyclo-oxygenase (COX) inhibitors may be helpful. The current evidence is conflicting regarding the role of COX-inhibitors in causing relapse in IBD. This case-control study examined the association between the use of COX inhibitors and relapse of IBD. Logistic regression was used to analyse the relationship between COX-inhibitors and IBD relapse. Overall COX inhibitor use (combined non-steroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 agents) had a negative association with relapse of IBD (adjusted OR 0.26, 95% CI 0.09–0.80). This negative association was confined to ulcerative colitis (UC) (adjusted OR = 0.06, 95% CI 0.01–0.50) and no association was found in Crohn’s disease (CD) patients (adjusted OR 1.25, 95% CI 0.18–7.46). The significant negative association between UC relapse and medication use was also seen with non-specific NSAIDs. Selective COX-2 inhibitor use was rare but non-significantly more common in stable patients. There was no association between low-dose aspirin or paracetamol use and relapse of CD or UC. We conclude that COX-inhibitor use was not associated with an increased risk of relapse in UC or CD, and may be protective in UC. Where indicated, NSAIDs should not be withheld from IBD patients.

Pathogenesis of neonatal necrotizing enterocolitis

Although necrotizing enterocolitis (NEC) is the most lethal gastrointestinal disease in the neonatal population, its pathogenesis is poorly understood. Risk factors include prematurity, bacterial colonization, and formula feeding. This review examines how mucosal injury permits opportunistic pathogens to breach the gut barrier and incite an inflammatory response that leads to sustained overproduction of mediators such as nitric oxide and its potent adduct, peroxynitrite. These mediators not only exacerbate the initial mucosal injury, but they also suppress the intestinal repair mechanisms, which further compromises the gut barrier and culminates in bacterial translocation, sepsis, and full-blown NEC.

Prostaglandin E₂ and polyenylphosphatidylcholine protect against intestinal fibrosis and regulate myofibroblast function

BACKGROUND

Intestinal fibrosis is a serious and often recurrent complication of inflammatory bowel disease despite surgical intervention. The anti-fibrotic potential of prostaglandin E2 (PGE2) and polyenylphosphatidylcholine (PC) was investigated using the murine model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced chronic intestinal inflammation and fibrosis, and murine and human intestinal myofibroblasts.

METHODS

Mice were treated with TNBS enemas weekly for 2 or 6 weeks ± PGE2 (10 mg/kg/day orally) or PC (200 mg/kg/day orally). Inflammation and fibrosis were histologically assessed and scored. Pro-inflammatory cytokines, TLR4, and ECM-related gene expression from the colonic tissue and cultured myofibroblasts were assessed by RT-qPCR. The levels of α-SMA(+) staining and endogenous PGE2 in vivo were also assessed.

RESULTS

Both PGE2 and PC treatment significantly decreased TNBS-induced intestinal inflammation and excess collagen deposition in vivo. This was accompanied by decreased α-SMA(+) staining in the lamina propria and lower collagen type I (COL1α1) expression. Endogenous PGE2 levels demonstrated that PC was not being converted into PGE2, thus mediating its effects primarily via PGE2-independent pathways. Both PGE2 and the PC isoform, 1,2-dilinoleoylphosphatidylcholine (DLPC), regulated primary mouse myofibroblast and CCD-18co COL1α1 production, and induced lower collagen type I to III and TGF-β1 to TGF-β3 ratios, demonstrating their ability to induced normal healing in the presence of phorbol 12-myristate 13-acetate (protein kinase C-dependent inducer of collagen production).

CONCLUSION

PGE2 and PC both have potent anti-fibrogenic potentials in their ability to regulate inflammatory cell and myofibroblast accumulation within inflamed tissue, to decrease pro-inflammatory cytokine expression and to maintain normal healing in an inflammatory environment.

Disruption of Escherichia coli Nissle 1917 K5 capsule biosynthesis, through loss of distinct kfi genes, modulates interaction with intestinal epithelial cells and impact on cell health

Escherichia coli Nissle 1917 (EcN) is among the best characterised probiotics, with a proven clinical impact in a range of conditions. Despite this, the mechanisms underlying these "probiotic effects" are not clearly defined. Here we applied random transposon mutagenesis to identify genes relevant to the interaction of EcN with intestinal epithelial cells. This demonstrated mutants disrupted in the kfiB gene, of the K5 capsule biosynthesis cluster, to be significantly enhanced in attachment to Caco-2 cells. However, this phenotype was distinct from that previously reported for EcN K5 deficient mutants (kfiC null mutants), prompting us to explore further the role of kfiB in EcN:Caco-2 interaction. Isogenic mutants with deletions in kfiB (EcNΔkfiB), or the more extensively characterised K5 capsule biosynthesis gene kfiC (EcNΔkfiC), were both shown to be capsule deficient, but displayed divergent phenotypes with regard to impact on Caco-2 cells. Compared with EcNΔkfiC and the EcN wild-type, EcNΔkfiB exhibited significantly greater attachment to Caco-2 cells, as well as apoptotic and cytotoxic effects. In contrast, EcNΔkfiC was comparable to the wild-type in these assays, but was shown to induce significantly greater COX-2 expression in Caco-2 cells. Distinct differences were also apparent in the pervading cell morphology and cellular aggregation between mutants. Overall, these observations reinforce the importance of the EcN K5 capsule in host-EcN interactions, but demonstrate that loss of distinct genes in the K5 pathway can modulate the impact of EcN on epithelial cell health.

Comparison of selective and non selective cyclo-oxygenase 2 inhibitors in experimental colitis exacerbation: role of leukotriene B4 and superoxide dismutase

CONTEXT

Nonsteroidal anti-inflammatory drugs are considered one of the most important causes of reactivation of inflammatory bowel disease. With regard to selective cyclo-oxygenase 2 inhibitors, the results are controversial in experimental colitis as well as in human studies.

OBJECTIVES

The aim this study is to compare nonsteroidal anti-inflammatory drugs effects, selective and non selective cyclo-oxygenase 2 inhibitors, in experimental colitis and contribute to the understanding of the mechanisms which nonsteroidal anti-inflammatory drugs provoke colitis exacerbation.

METHODS

Six groups of rats: without colitis, with colitis, and colitis treated with celecoxib, ketoprofen, indometacin or diclofenac. Survival rates, hemoglobin, plasmatic albumin, colonic tissue of interleukin-1ß, interleukin-6, tumor necrosis factor alpha, prostaglandin E2, catalase, superoxide dismutase, thiobarbituric acid-reactive substances, chemiluminescence induced by tert-butil hydroperoxides, and tissue and plasmatic leukotriene B4 were determined.

RESULTS

The groups treated with diclofenac or indometacin presented lower survival rates, hemoglobin and albumin, higher tissue and plasmatic leukotriene B4 and tissue superoxide dismutase than the group treated with celecoxib. Ketoprofen presented an intermediary behavior between diclofenac/indometacin and celecoxib, concerning to survival rate and albumin. The groups without colitis, with colitis and with colitis treated with celecoxib showed leukotriene B4 and superoxide dismutase lower levels than the groups treated with nonselective cyclo-oxygenase 2 inhibitors.

CONCLUSIONS

Diclofenac and indometacin presented the highest degree of induced colitis exacerbation with nonsteroidal anti-inflammatory drugs, celecoxib did not show colitis exacerbation, and ketoprofen presented an intermediary behavior between diclofenac/indometacin and celecoxib. These results suggest that leukotriene B4 and superoxide dismutase can be involved in the exacerbation of experimental colitis by nonselective nonsteroidal anti-inflammatory drugs.

IBD candidate genes and intestinal barrier regulation

Technological advances in the large scale analysis of human genetics have generated profound insights into possible genetic contributions to chronic diseases including the inflammatory bowel diseases (IBDs), Crohn's disease and ulcerative colitis. To date, 163 distinct genetic risk loci have been associated with either Crohn's disease or ulcerative colitis, with a substantial degree of genetic overlap between these 2 conditions. Although many risk variants show a reproducible correlation with disease, individual gene associations only affect a subset of patients, and the functional contribution(s) of these risk variants to the onset of IBD is largely undetermined. Although studies in twins have demonstrated that the development of IBD is not mediated solely by genetic risk, it is nevertheless important to elucidate the functional consequences of risk variants for gene function in relevant cell types known to regulate key physiological processes that are compromised in IBD. This article will discuss IBD candidate genes that are known to be, or are suspected of being, involved in regulating the intestinal epithelial barrier and several of the physiological processes presided over by this dynamic and versatile layer of cells. This will include assembly and regulation of tight junctions, cell adhesion and polarity, mucus and glycoprotein regulation, bacterial sensing, membrane transport, epithelial differentiation, and restitution.

Opposing roles of prostaglandin D2 receptors in ulcerative colitis

Proresolution functions were reported for PGD2 in colitis, but the role of its two receptors, D-type prostanoid (DP) and, in particular, chemoattractant receptor homologous molecule expressed on Th2 cells (CRTH2), is less well defined. We investigated DP and CRTH2 expression and function during human and murine ulcerative colitis (UC). Expression of receptors was measured by flow cytometry on peripheral blood leukocytes and by immunohistochemistry and immunoblotting in colon biopsies of patients with active UC and healthy individuals. Receptor involvement in UC was evaluated in a mouse model of dextran sulfate sodium colitis. DP and CRTH2 expression changed in leukocytes of patients with active UC in a differential manner. In UC patients, DP showed higher expression in neutrophils but lower in monocytes as compared with control subjects. In contrast, CRTH2 was decreased in eosinophils, NK, and CD3(+) T cells but not in monocytes and CD3(+)/CD4(+) T cells. The decrease of CRTH2 on blood eosinophils clearly correlated with disease activity. DP correlated positively with disease activity in eosinophils but inversely in neutrophils. CRTH2 internalized upon treatment with PGD2 and 11-dehydro TXB2 in eosinophils of controls. Biopsies of UC patients revealed an increase of CRTH2-positive cells in the colonic mucosa and high CRTH2 protein content. The CRTH2 antagonist CAY10595 improved, whereas the DP antagonist MK0524 worsened inflammation in murine colitis. DP and CRTH2 play differential roles in UC. Although expression of CRTH2 on blood leukocytes is downregulated in UC, CRTH2 is present in colon tissue, where it may contribute to inflammation, whereas DP most likely promotes anti-inflammatory actions.

iNOS-dependent increase in colonic mucus thickness in DSS-colitic rats

Aim

To investigate colonic mucus thickness in vivo in health and during experimental inflammatory bowel disease.

Methods

Colitis was induced with 5% DSS in drinking water for 8 days prior to experiment, when the descending colonic mucosa of anesthetized rats was studied using intravital microscopy. Mucus thickness was measured with micropipettes attached to a micromanipulator. To assess the contributions of NOS and prostaglandins in the regulation of colonic mucus thickness, the non-selective NOS-inhibitor L-NNA (10 mg/kg bolus followed by 3 mg/kg/h), the selective iNOS-inhibitor L-NIL (10 mg/kg bolus followed by 3 mg/kg/h) and the non-selective COX-inhibitor diclofenac (5 mg/kg) were administered intravenously prior to experiment. To further investigate the role of iNOS in the regulation of colonic mucus thickness, iNOS −/− mice were used.

Results

Colitic rats had a thicker firmly adherent mucus layer following 8 days of DSS treatment than untreated rats (88±2 µm vs 76±1 µm). During induction of colitis, the thickness of the colonic mucus layer initially decreased but was from day 3 significantly thicker than in untreated rats. Diclofenac reduced the mucus thickness similarly in colitic and untreated rats (−16±5 µm vs −14±2 µm). While L-NNA had no effect on colonic mucus thickness in DSS or untreated controls (+3±2 µm vs +3±1 µm), L-NIL reduced the mucus thickness significantly more in colitic rats than in controls (−33±4 µm vs −10±3 µm). The importance of iNOS in regulating the colonic mucus thickness was confirmed in iNOS−/− mice, which had thinner colonic mucus than wild-type mice (35±3 µm vs 50±2 µm, respectively). Furthermore, immunohistochemistry revealed increased levels of iNOS in the colonic surface epithelium following DSS treatment.

Conclusion

Both prostaglandins and nitric oxide regulate basal colonic mucus thickness. During onset of colitis, the thickness of the mucus layer is initially reduced followed by an iNOS mediated increase.

Iron-ascorbate-mediated lipid peroxidation causes epigenetic changes in the antioxidant defense in intestinal epithelial cells: impact on inflammation

Introduction

The gastrointestinal tract is frequently exposed to noxious stimuli that may cause oxidative stress, inflammation and injury. Intraluminal pro-oxidants from ingested nutrients especially iron salts and ascorbic acid frequently consumed together, can lead to catalytic formation of oxygen-derived free radicals that ultimately overwhelm the cellular antioxidant defense and lead to cell damage.

Hypothesis

Since the mechanisms remain sketchy, efforts have been exerted to evaluate the role of epigenetics in modulating components of endogenous enzymatic antioxidants in the intestine. To this end, Caco-2/15 cells were exposed to the iron-ascorbate oxygen radical-generating system.

Results

Fe/Asc induced a significant increase in lipid peroxidation as reflected by the elevated formation of malondialdehyde along with the alteration of antioxidant defense as evidenced by raised superoxide dismutase 2 (SOD2) and diminished glutathione peroxidase (GPx) activities and genes. Consequently, there was an up-regulation of inflammatory processes illustrated by the activation of NF-κB transcription factor, the higher production of interleukin-6 and cycloxygenase-2 as well as the decrease of IκB. Assessment of promoter’s methylation revealed decreased levels for SOD2 and increased degree for GPx2. On the other hand, pre-incubation of Caco-2/15 cells with 5-Aza-2′-deoxycytidine, a demethylating agent, or Trolox antioxidant normalized the activities of SOD2 and GPx, reduced lipid peroxidation and prevented inflammation.

Conclusion

Redox and inflammatory modifications in response to Fe/Asc -mediated lipid peroxidation may implicate epigenetic methylation.

Lymphocytic colitis is associated with increased pro-inflammatory cytokine profile and up regulation of prostaglandin receptor EP4

Microscopic colitis (MC) is comprised of two entities, lymphocytic (LC) and collagenous colitis. Up to 20% of patients with chronic diarrhea that have a normal appearing colonoscopy will be diagnosed with MC. Since MC was first described less than 40 years ago, little is known about the mechanisms involved in disease pathogenesis. Nonsteroidal anti-inflammatory drugs are associated with an increased risk of MC and some reports suggest a dysregulation in prostaglandin production. Recent genome wide screens have found an association between prostaglandin receptor EP4 expression and inflammatory bowel disease; however, EP4 expression has never been studied in MC. The aim of this study was to assess colonic mucosal inflammatory cytokine profiles in patients with LC and to assess expression of the prostaglandin receptor EP4. Colonic mucosal biopsies were obtained from patients undergoing colonoscopy for investigation of diarrhea and in those undergoing colon cancer screening. Following histological assessment, expression of cytokines and the prostaglandin receptor EP4 was analyzed using real-time reverse transcriptase-PCR and immunohistochemistry. Patients with LC had markedly increased mRNA expression for TNF-α, IFN-γ and IL-8 compared to normal controls (p<0.001). No significant differences were noted for IL-1β, IL-4, IL-10 or IL-12/23. Interestingly, those with LC had increased EP4 receptor expression, which positively correlated with increased TNF-α expression. This is the first report to demonstrate that LC is associated with increased TNF-α, INF-γ and IL-8 concurrent with a marked up-regulation of EP4. These findings add to our knowledge on the pathogenesis of LC and may give rise to possible new therapeutic and/or diagnostic tools in the management of MC.

Multifaceted roles of PGE2 in inflammation and cancer

Prostaglandin E(2) (PGE(2)) is a bioactive lipid that elicits a wide range of biological effects associated with inflammation and cancer. PGE(2) exerts diverse effects on cell proliferation, apoptosis, angiogenesis, inflammation, and immune surveillance. This review concentrates primarily on gastrointestinal cancers, where the actions of PGE(2) are most prominent, most likely due to the constant exposure to dietary and environmental insults and the intrinsic role of PGE(2) in tissue homeostasis. A discussion of recent efforts to elucidate the complex and interconnected pathways that link PGE(2) signaling with inflammation and cancer is provided, supported by the abundant literature showing a protective effect of NSAIDs and the therapeutic efficacy of targeting mPGES-1 or EP receptors for cancer prevention. However, suppressing PGE(2) formation as a means of providing chemoprotection against all cancers may not ultimately be tenable, undoubtedly the situation for patients with inflammatory bowel disease. Future studies to fully understand the complex role of PGE(2) in both inflammation and cancer will be required to develop novel strategies for cancer prevention that are both effective and safe.

Cyclooxygenase-2 deficiency leads to intestinal barrier dysfunction and increased mortality during polymicrobial sepsis

Sepsis remains the leading cause of death in critically ill patients, despite modern advances in critical care. Intestinal barrier dysfunction may lead to secondary bacterial translocation and the development of the multiple organ dysfunction syndrome during sepsis. Cyclooxygenase (COX)-2 is highly upregulated in the intestine during sepsis, and we hypothesized that it may be critical in the maintenance of intestinal epithelial barrier function during peritonitis-induced polymicrobial sepsis. COX-2(-/-) and COX-2(+/+) BALB/c mice underwent cecal ligation and puncture (CLP) or sham surgery. Mice chimeric for COX-2 were derived by bone marrow transplantation and underwent CLP. C2BBe1 cells, an intestinal epithelial cell line, were treated with the COX-2 inhibitor NS-398, PGD(2), or vehicle and stimulated with cytokines. COX-2(-/-) mice developed exaggerated bacteremia and increased mortality compared with COX-2(+/+) mice following CLP. Mice chimeric for COX-2 exhibited the recipient phenotype, suggesting that epithelial COX-2 expression in the ileum attenuates bacteremia following CLP. Absence of COX-2 significantly increased epithelial permeability of the ileum and reduced expression of the tight junction proteins zonula occludens-1, occludin, and claudin-1 in the ileum following CLP. Furthermore, PGD(2) attenuated cytokine-induced hyperpermeability and zonula occludens-1 downregulation in NS-398-treated C2BBe1 cells. Our findings reveal that absence of COX-2 is associated with enhanced intestinal epithelial permeability and leads to exaggerated bacterial translocation and increased mortality during peritonitis-induced sepsis. Taken together, our results suggest that epithelial expression of COX-2 in the ileum is a critical modulator of tight junction protein expression and intestinal barrier function during sepsis.

Toll-like receptor 4 signaling integrates intestinal inflammation with tumorigenesis: lessons from the murine model of colitis-associated cancer

Chronic inflammation has long been implicated as a predisposition for cancer, but the underlying mechanism for how this occurs has remained obscure. Ulcerative colitis (UC) is a chronic inflammatory disorder of the large intestine which is known to be highly linked to colorectal cancer. During chronic inflammation the intestinal mucosa is in a constant cycle of injury and repair resulting in aberrant epithelial proliferation, a process that increases the risk of neoplastic transformation. In particular, the coexistence of commensal flora in the intestine plays an important role in the regulation of mucosal restitution after epithelial injury. It has become apparent that signaling through toll-like receptors (TLRs), the receptor family recognizing pathogen-associated molecular patterns, is crucial to intestinal epithelial proliferation and mucosal restitution. We have recently described two important downstream pathways underlying TLR4-mediated epithelial proliferation in a mouse model of colitis-associated cancer; i.e., cyclooxygenase 2 (COX-2)-mediated production of prostaglandin E₂ (PGE₂), and induction of specific ligands for epidermal growth factor receptor (EGFR). These two pathways are closely involved with mucosal levels of PGE₂ and other prostanoids such as 15-deoxy-delta 12,14-prostaglandin-J2 (15d-PGJ2). Understanding the fine interplay between the TLR signaling and intestinal tumorigenesis in the setting of chronic inflammation can contribute to establishing a novel treatment strategy for inflammation-associated cancers.

Role of eosinophils in inflammatory bowel and gastrointestinal diseases

Inflammatory bowel diseases (IBD) are characterized by the invasion of leukocytes into the intestinal mucosa. However, a mixed inflammatory picture is observed that includes neutrophils, lymphocytes, monocytes, and eosinophils. To this day, the role of eosinophils in health and in disease remains unclear. Investigations into their function stem primarily from allergic diseases, asthma, and parasitic infections. This makes it even more difficult to discern a role for the fascinating eosinophil in IBDs because, unlike the lung or the skin, eosinophils reside in normal intestinal mucosa and increase in disease states; consequently, an intricate system must regulate their migration and numbers. These granulocytes are equipped with the machinery to participate in gastrointestinal (GI) inflammation and in the susceptible microenvironment, they may initiate or perpetuate an inflammatory response. A significant body of literature characterizes eosinophils present in the GI microenvironment where they have the potential to interact with other resident cells, thus promoting intestinal remodeling, mucus production, epithelial barrier, cytokine production, angiogenesis, and neuropeptide release. A number of lines of evidence support both potential beneficial and deleterious roles of eosinophils in the gut. Although studies from the gut and other mucosal organs suggest eosinophils affect mucosal GI inflammation, definitive roles for eosinophils in IBDs await discovery.

Review article: delivery and efficacy of topical 5-aminosalicylic acid (mesalazine) therapy in the treatment of ulcerative colitis

BACKGROUND

The use of topical therapy in the treatment of ulcerative colitis has declined in recent years despite evidence of good efficacy.

AIMS

To review US prescription trends for 5-aminosalicylic acid (5-ASA) since the US approval of Asacol extended-release oral mesalazine (mesalamine) in 1992; to estimate the optimal level of 5-ASA exposure in the distal colon; to determine factors influencing distal colonic exposures; and to compare the effectiveness of different 5-ASA formulations (oral, topical suspension, foam, suppositories) in clinical trials.

METHODS

Review of clinical trials, physiologic studies and prescription trends of various mesalazine formulations for treatment of distal ulcerative colitis.

RESULTS

Between 1992 and 2009, prescriptions for oral mesalazine increased sixfold, whereas topical suspensions declined by 10%. In clinical trials, topical therapy resulted in higher remission and clinical response rates than oral therapy, with trends to earlier improvement. The mucosal concentrations of 5-ASA achieved by topical agents in the distal colon were up to 200-fold higher than those achieved by oral administration alone. Despite active colitis, over 40% of a topically administered 4 g 5-ASA suspension (equal to 1.6 g) reached the sigmoid colon. This likely represents a therapeutic exposure of 5-ASA. Although topical therapies are less convenient than oral medications, treatment algorithms have failed to take into account quality of life improvements resulting from more rapid and complete treatment response.

CONCLUSIONS

Topical mesalazine therapy is superior to oral therapy in distal ulcerative colitis for both therapeutic response and drug delivery. Practice patterns should be re-evaluated in light of this information.

Recombinant lactobacilli expressing linoleic acid isomerase can modulate the fatty acid composition of host adipose tissue in mice

We have previously demonstrated that oral administration of a metabolically active Bifidobacterium breve strain, with ability to form cis-9, trans-11 conjugated linoleic acid (CLA), resulted in modulation of the fatty acid composition of the host, including significantly elevated concentrations of c9, t11 CLA and omega-3 (n-3) fatty acids in liver and adipose tissue. In this study, we investigated whether a recombinant lactobacillus expressing linoleic acid isomerase (responsible for production of t10, c12 CLA) from Propionibacterium acnes (PAI) could influence the fatty acid composition of different tissues in a mouse model. Linoleic-acid-supplemented diets (2 %, w/w) were fed in combination with either a recombinant t10, c12 CLA-producing Lactobacillus paracasei NFBC 338 (Lb338), or an isogenic (vector-containing) control strain, to BALB/c mice for 8 weeks. A third group of mice received linoleic acid alone (2 %, w/w). Tissue fatty acid composition was assessed by GLC at the end of the trial. Ingestion of the strain expressing linoleic acid isomerase was associated with a 4-fold increase (P<0.001) in t10, c12 CLA in adipose tissues of the mice when compared with mice that received the isogenic non-CLA-producing strain. The livers of the mice that received the recombinant CLA-producing Lb338 also contained a 2.5-fold (albeit not significantly) higher concentration of t10, c12 CLA, compared to the control group. These data demonstrate that a single gene (encoding linoleic acid isomerase) expressed in an intestinal microbe can influence the fatty acid composition of host fat.

Western-style diets induce macrophage infiltration and contribute to colitis-associated carcinogenesis

BACKGROUND AND AIM

A Western-style diet (WD) is known to play an important role in inflammatory bowel disease and colon carcinogenesis. The purpose of this study was to understand the role of macrophages in WD-induced colitis associated with carcinogenesis.

METHODS

Male BALB/c mice were fed a WD or a control diet (CD) for 4 weeks and exposed to azoxymethane (AOM) followed by 2% dextran sulfate sodium (DSS) for 7 days.

RESULTS

The WD increased susceptibility to DSS-induced inflammation and accelerated the infiltration of macrophages. The incidence and multiplicity of colon tumors were higher in mice fed the WD than in those fed the CD (P < 0.05). Levels of prostaglandin-endoperoxide synthase (PTGS) 2 and prostaglandin (PG) E(2) in the colon were higher after treatment with AOM and DSS in mice fed the WD than in those fed the CD. In addition, WD consumption increased the DNA binding activity of nuclear factor-kappaB and the serum concentration of tumor necrosis factor (TNF)-α. Mice fed the WD had higher numbers of F4/80-positive cells surrounding cancer cells compared with mice fed the CD. These cells expressed PTGS2, TNF-α and β-catenin, which are up-regulated by the WD. We also found that the WD increased unphosphorylated β-catenin accumulation in the cytoplasm and nucleus of colon cancer cells.

CONCLUSIONS

A WD increases the susceptibility to DSS-induced inflammation and accelerates the infiltration of macrophages. In turn, this resulted in the development and progression of colon cancer.

Fatty acids from fish: the anti-inflammatory potential of long-chain omega-3 fatty acids

Omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFA) are precursors of potent lipid mediators, termed eicosanoids, which play an important role in the regulation of inflammation. Eicosanoids derived from n-6 PUFAs (e.g., arachidonic acid) have proinflammatory and immunoactive functions, whereas eicosanoids derived from n-3 PUFAs [e.g., eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] have anti-inflammatory properties, traditionally attributed to their ability to inhibit the formation of n-6 PUFA-derived eicosanoids. While the typical Western diet has a much greater ratio of n-6 PUFAs compared with n-3 PUFAs, research has shown that by increasing the ratio of n-3 to n-6 fatty acids in the diet, and consequently favoring the production of EPA in the body, or by increasing the dietary intake of EPA and DHA through consumption of fatty fish or fish-oil supplements, reductions may be achieved in the incidence of many chronic diseases that involve inflammatory processes; most notably, these include cardiovascular diseases, inflammatory bowel disease (IBD), cancer, and rheumatoid arthritis, but psychiatric and neurodegenerative illnesses are other examples.

The role of prostaglandin E2 (PGE 2) in toll-like receptor 4 (TLR4)-mediated colitis-associated neoplasia

Background

We have previously found that TLR4-deficient (TLR4-/-) mice demonstrate decreased expression of mucosal PGE ₂ and are protected against colitis-associated neoplasia. However, it is still unclear whether PGE ₂ is the central factor downstream of TLR4 signaling that promotes intestinal tumorigenesis. To further elucidate critical downstream pathways involving TLR4-mediated intestinal tumorigenesis, we examined the effects of exogenously administered PGE ₂ in TLR4-/- mice to see if PGE ₂ bypasses the protection from colitis-associated tumorigenesis.

Method

Mouse colitis-associated neoplasia was induced by azoxymethane (AOM) injection followed by two cycles of dextran sodium sulfate (DSS) treatment. Two different doses of PGE ₂ (high dose group, 200 μg, n = 8; and low dose group, 100 μg, n = 6) were administered daily during recovery period of colitis by gavage feeding. Another group was given PGE ₂ during DSS treatment (200 μg, n = 5). Inflammation and dysplasia were assessed histologically. Mucosal Cox-2 and amphiregulin (AR) expression, prostanoid synthesis, and EGFR activation were analyzed.

Results

In control mice treated with PBS, the average number of tumors was greater in WT mice (n = 13) than in TLR4-/- mice (n = 7). High dose but not low dose PGE ₂ treatment caused an increase in epithelial proliferation. 28.6% of PBS-treated TLR4-/- mice developed dysplasia (tumors/animal: 0.4 ± 0.2). By contrast, 75.0% (tumors/animal: 1.5 ± 1.2, P < 0.05) of the high dose group and 33.3% (tumors/animal: 0.3 ± 0.5) of the low dose group developed dysplasia in TLR4-/- mice. Tumor size was also increased by high dose PGE ₂ treatment. Endogenous prostanoid synthesis was differentially affected by PGE ₂ treatment during acute and recovery phases of colitis. Exogenous administration of PGE ₂ increased colitis-associated tumorigenesis but this only occurred during the recovery phase. Lastly, PGE ₂ treatment increased mucosal expression of AR and Cox-2, thus inducing EGFR activation and forming a positive feedback mechanism to amplify mucosal Cox-2.

Conclusions

These results highlight the importance of PGE ₂ as a central downstream molecule involving TLR4-mediated intestinal tumorigenesis.

Impact of administered bifidobacterium on murine host fatty acid composition

Recently, we reported that administration of Bifidobacteria resulted in increased concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in murine adipose tissue [1]. The objective of this study was to assess the impact of co-administration of Bifidobacterium breve NCIMB 702258 and the substrate for EPA, alpha-linolenic acid, on host fatty acid composition. alpha-Linolenic acid-supplemented diets (1%, wt/wt) were fed to mice (n = 8), with or without B. breve NCIMB 702258 (daily dose of 10(9) microorganisms) for 8 weeks. Two further groups received either supplement of B. breve alone or unsupplemented diet. Tissue fatty acid composition was assessed by gas liquid chromatography. Dietary supplementation of alpha-linolenic acid resulted in higher (P < 0.05) alpha-linolenic acid and EPA concentrations in liver and adipose tissue and lower (P < 0.05) arachidonic acid in liver, adipose tissue and brain compared with mice that did not receive alpha-linolenic acid. Supplementation with B. breve NCIMB 702258 in combination with alpha-linolenic acid resulted in elevated (P < 0.05) liver EPA concentrations compared with alpha-linolenic acid supplementation alone. Furthermore, the former group had higher (P < 0.05) DHA in brain compared with the latter group. These results suggest a role for interactions between fatty acids and commensals in the gastrointestinal tract. This interaction between administered microbes and fatty acids could result in a highly effective nutritional approach to the therapy of a variety of inflammatory and neurodegenerative conditions.

Non Steroidal Anti-Inflammatory Drugs and Inflammatory Bowel Disease

Inflammatory Bowel Diseases (IBD) are an immune mediated chronic or relapsing disorders of the gastrointestinal (GI) tract. IBD is characterized by a chronic intestinal inflammatory process with various components contributing to the pathogenesis of the disease including environmental factors such as smoking or use of Non Steroidal Anti-Inflammatory Drugs (NSAIDS). NSAIDS are among the most commonly used medications for the treatment of various inflammatory conditions. The main factor limiting NSAIDS use is the concern for the development of gastrointestinal toxicity including mucosal injury. A possible association between the use of NSAIDS and the onset or relapse of IBD has been repeatedly suggested. This article will review the current concepts and evidence of the relationship between IBD and NSAIDS.

Cyclooxygenase-derived mediators regulate the immunological control of Strongyloides venezuelensis infection

The aim of this study was to define the immunoregulatory role of prostaglandins in a mouse model of Strongyloides venezuelensis infection. Strongyloides venezuelensis induced an increase of eosinophils and mononuclear cells in the blood, peritoneal cavity fluid, and bronchoalveolar lavage fluid. Treatment with the dual cyclooxygenase (COX-1/-2) inhibitors indomethacin and ibuprofen, and the COX-2-selective inhibitor celecoxib partially blocked these cellular responses and was associated with enhanced numbers of infective larvae in the lung and adult worms in the duodenum. However, the drugs did not interfere with worm fertility. Cyclooxygenase inhibitors also inhibited the production of the T-helper type 2 (Th2) mediators IL-5, IgG1, and IgE, while indomethacin alone also inhibited IL-4, IL-10, and IgG2a. Cyclooxygenase inhibitors tended to enhance the Th1 mediators IL-12 and IFN-gamma. This shift away from Th2 immunity in cyclooxygenase inhibitor-treated mice correlated with reduced prostaglandin E(2) (PGE(2)) production in infected duodenal tissue. As PGE(2) is a well-characterized driver of Th2 immunity, we speculate that reduced production of this lipid might be involved in the shift toward a Th1 phenotype, favoring parasitism by S. venezuelensis. These findings provide new evidence that cyclooxygenase-derived lipids play a role in regulating host defenses against Strongyloides, and support the exploration of eicosanoid signaling for identifying novel preventive and therapeutic modalities against these infections.