Tumour necrosis factor and Crohn's disease

New Insights into the Mechanisms of Action of Anti-Tumor Necrosis Factor-α Monoclonal Antibodies in Inflammatory Bowel Disease

Tumor necrosis factor alpha (TNF-α) has been widely accepted as a therapeutic target for inflammatory disorders including inflammatory bowel disease. Anti-TNF-α monoclonal antibodies (mAbs) including infliximab, adalimumab, golimumab, and certolizumab pegol have revolutionized therapy for these chronic inflammatory disorders. These agents are potent inhibitors of TNF-α, but significant evidence points to the fact that their actions extend beyond simple neutralization of the cytokine. Recent advances in understanding the mechanism of action of anti-TNF-α mAbs has discovered a number of previously unrecognized actions that are likely to be relevant in mediating their anti-inflammatory effects. Many of those actions are mediated by the binding of the antibodies to transmembrane TNF-α (tmTNF-α) and involve complex interactions with other molecular factors and cells. In this review, we have highlighted new information on the mechanism of actions of anti-TNF-α mAbs, from in vitro and in vivo studies. Despite obvious benefits in many patients, the clinical use of these antibodies are hampered by the fact that some patients do not respond to them, and among patients who do respond, many will develop recurrent disease despite continued dosing. Although pharmacokinetic factors explain some of the observed cases of partial or complete resistance to the effects of anti-TNF-α mAbs, other nonresponder patients may be resistant to those agents mechanism of action. A more thorough understanding of the mechanism of action of anti-TNF-α mAbs may allow the development of strategies to individualize therapy and to overcome resistance.

Hepatic manifestations of non-steroidal inflammatory bowel disease therapy

Inflammatory bowel disease (IBD) is composed of Crohn's disease and ulcerative colitis and is manifested by both bowel-related and extraintestinal manifestations. Recently the number of therapeutic options available to treat IBD has dramatically increased, with each new medication having its own mechanism of action and side effect profile. A complete understanding of the hepatotoxicity of these medications is important in order to distinguish these complications from the hepatic manifestations of IBD. This review seeks to evaluate the hepatobiliary complications of non-steroid based IBD medications and aide providers in the recognition and management of these side-effects.

Orally administered extract from Prunella vulgaris attenuates spontaneous colitis in mdr1a-/- mice

AIM: To investigate the ability of a Prunella vulgaris (P. vulgaris) ethanolic extract to attenuate spontaneous typhlocolitis in mdr1a^-/- mice.

METHODS: Vehicle (5% ethanol) or P. vulgaris ethanolic extract (2.4 mg/d) were administered daily by oral gavage to mdr1a^-/- or wild type FVB^WT mice from 6 wk of age up to 20 wk of age. Clinical signs of disease were noted by monitoring weight loss. Mice experiencing weight loss in excess of 15% were removed from the study. At the time mice were removed from the study, blood and colon tissue were collected for analyses that included histological evaluation of lesions, inflammatory cytokine levels, and myeloperoxidase activity.

RESULTS: Administration of P. vulgaris extracts to mdr1a^-/- mice delayed onset of colitis and reduced severity of mucosal inflammation when compared to vehicle-treated mdr1a^-/- mice. Oral administration of the P. vulgaris extract resulted in reduced (P < 0.05) serum levels of IL-10 (4.6 ± 2 vs 19.4 ± 4), CXCL9 (1319.0 ± 277 vs 3901.0 ± 858), and TNFα (9.9 ± 3 vs 14.8 ± 1) as well as reduced gene expression by more than two-fold for Ccl2, Ccl20, Cxcl1, Cxcl9, IL-1α, Mmp10, VCAM-1, ICAM, IL-2, and TNFα in the colonic mucosa of mdr1a^-/- mice compared to vehicle-treated mdr1a^-/- mice. Histologically, several microscopic parameters were reduced (P < 0.05) in P. vulgaris-treated mdr1a^-/- mice, as was myeloperoxidase activity in the colon (2.49 ± 0.16 vs 3.36 ± 0.06, P < 0.05). The numbers of CD4⁺ T cells (2031.9 ± 412.1 vs 5054.5 ± 809.5) and germinal center B cells (2749.6 ± 473.7 vs 4934.0 ± 645.9) observed in the cecal tonsils of P. vulgaris-treated mdr1a^-/- were significantly reduced (P < 0.05) from vehicle-treated mdr1a^-/- mice. Vehicle-treated mdr1a^-/- mice were found to produce serum antibodies to antigens derived from members of the intestinal microbiota, indicative of severe colitis and a loss of adaptive tolerance to the members of the microbiota. These serum antibodies were greatly reduced or absent in P. vulgaris-treated mdr1a^-/- mice.

CONCLUSION: The anti-inflammatory activity of P. vulgaris ethanolic extract effectively attenuated the severity of intestinal inflammation in mdr1a^-/- mice.

Id1 expression in endothelial cells of the colon is required for normal response to injury

Inhibitor of DNA binding (ID)-1 is important for angiogenesis during embryogenesis and tumor development. Whether ID1 expression in endothelial cells of the colon is required for normal response to injury is unknown. We demonstrate that Id1 is up-regulated in colonic endothelial cells in an experimental model of colitis and in the inflamed mucosa of patients with inflammatory bowel disease. Because prostaglandin E2 and tumor necrosis factor-α are also elevated in colitis, we determined whether these factors could induce ID1 transcription in cultured endothelial cells. Tumor necrosis factor-α stimulated ID1 transcription via early growth response 1 protein (Egr-1). By contrast, the induction of ID1 by prostaglandin E2 was mediated by cAMP response element-binding protein (CREB). To determine whether the increased ID1 levels in the endothelial cells of inflamed mucosa were an adaptive response that modulated the severity of tissue injury, Id1 was conditionally depleted in the endothelium of mice, which sensitized the mice to more severe chemical colitis, including more severe diarrhea, bleeding, and histological injury, and shorter colon compared with control mice. Moreover, depletion of Id1 in the vasculature was associated with increased CD31(+) aggregates and increased vascular permeability in inflamed mucosa compared with those in Id1 wild-type control mice. These results suggest that endothelial ID1 up-regulation in inflamed colonic mucosa is an adaptive response that modulates the severity of tissue injury.

Interleukin 34: a new modulator of human and experimental inflammatory bowel disease

IBD (inflammatory bowel disease), where CD (Crohn's disease) and UC (ulcerative colitis) represent the two main forms, are chronic inflammatory conditions of the intestine. Macrophages play a central role in IBD pathogenesis and are regulated by major differentiation factors such as CSF-1 (colony-stimulating factor 1) in homoeostasis and inflammation. IL (interleukin)-34 has recently been discovered as a second ligand for CSF-1R (CSF-1 receptor). However, expression and involvement of IL-34 in IBD remain unknown. In the present paper, we investigated the expression of IL34, CSF1 and their shared receptor CSF1R in normal human ileum and colon, in inflamed and non-inflamed tissues of CD and UC patients, and in a mouse model of experimental colitis. We found distinct expression patterns of IL34 and CSF1 in ileum and colon, with higher IL34 in ileum and, in contrast, higher CSF1 in colon. Furthermore, IL34 and CSF1 expression was increased with inflammation in IBD patients and in experimental colitis. In humans, infiltrating cells of the lamina propria and intestinal epithelial cells expressed IL-34, and TNF-α (tumour necrosis factor α) regulated IL-34 expression in intestinal epithelial cells through the NF-κB (nuclear factor κB) pathway. These data demonstrate the expression pattern of IL-34 in ileum and colon and suggest IL-34 as a new modulator of inflammation in IBD.

The macrophage differentiation factor interleukin-34, produced by intestinal epithelial cells, is up-regulated in patients with inflammatory bowel disease, and may be a novel modulator of intestinal inflammation.

Managing refractory Crohn's disease: challenges and solutions

The goals of treatment for active Crohn’s disease (CD) are to achieve clinical remission and improve quality of life. Conventional therapeutics for moderate-to-severe CD include 5-aminosalicylic acid, corticosteroids, purine analogs, azathioprine, and 6-mercaptopurine. Patients who fail to respond to conventional therapy are treated with tumor necrosis factor (TNF)-α inhibitors such as infliximab and adalimumab, but their efficacy is limited due to primary nonresponse or loss of response. It is suggested that this requires switch to another TNF-α inhibitor, a combination therapy with TNF-α blockade plus azathioprine, or granulocyte and monocyte adsorptive apheresis, and that other therapeutic options having different mechanisms of action, such as blockade of inflammatory cytokines or adhesion molecules, are needed. Natalizumab and vedolizumab are neutralizing antibodies directed against integrin α4 and α4β7, respectively. Ustekinumab is a neutralizing antibody directed against the receptors for interleukin-12 and interleukin-23. Here, we provide an overview of therapeutic treatments that are effective and currently available for CD patients, as well as some that likely will be available in the near future. We also discuss the advantages of managing patients with refractory CD using a combination of TNF-α inhibitors plus azathioprine or intensive monocyte adsorptive apheresis.

(-)-Epicatechin in the prevention of tumor necrosis alpha-induced loss of Caco-2 cell barrier integrity

An increased permeability of the intestinal barrier is proposed as a major event in the pathophysiology of inflammatory bowel diseases (IBD). Tumor necrosis alpha (TNFα) plays a central role in IBD pathogenesis, in part promoting tight function (TJ) barrier dysfunction. Food extracts enriched in (-)-epicatechin (EC) prevent the development or improve the progression of IBD in animal models. This study investigated the capacity of EC to inhibit TNFα-induced permeabilization of Caco-2 cell monolayers, characterizing the underlying mechanisms. Caco-2 cells differentiated into intestinal epithelial cells were incubated in the absence/presence of TNFα, with or without the addition of 0.5-5 μM EC. TNFα triggered cell monolayer permeabilization, decreasing transepithelial electrical resistance (TEER) and increasing the paracellular transport of fluorescein sulfonic acid. The permeabilizing effects of TNFα were not due to Caco-2 cell apoptosis as evaluated by DNA fragmentation, caspase 3 and 9 activation, and cell morphology. EC prevented TNFα-triggered Caco-2 monolayer permeabilization and acted inhibiting the associated: (i) NADPH oxidase (NOX)-mediated increased oxidant production, (ii) NF-κB (IκBα phosphorylation, p50 and RelA nuclear transport, and nuclear NF-κB-DNA binding) and ERK1/2 activation, (iii) increased myosin light kinase expression, and decreased TJ protein ZO-1 levels. In summary, EC prevented TNFα-mediated Caco-2 cell barrier permeabilization in part through the inhibition of NOX/NF-κB activation and downstream TJ disruption. Diets rich in EC could contribute to ameliorate IBD-associated increased intestinal permeability.

Strengthening of the intestinal epithelial tight junction by Bifidobacterium bifidum

Epithelial barrier dysfunction has been implicated as one of the major contributors to the pathogenesis of inflammatory bowel disease. The increase in intestinal permeability allows the translocation of luminal antigens across the intestinal epithelium, leading to the exacerbation of colitis. Thus, therapies targeted at specifically restoring tight junction barrier function are thought to have great potential as an alternative or supplement to immunology-based therapies. In this study, we screened Bifidobacterium, Enterococcus, and Lactobacillus species for beneficial microbes to strengthen the intestinal epithelial barrier, using the human intestinal epithelial cell line (Caco-2) in an in vitro assay. Some Bifidobacterium and Lactobacillus species prevented epithelial barrier disruption induced by TNF-α, as assessed by measuring the transepithelial electrical resistance (TER). Furthermore, live Bifidobacterium species promoted wound repair in Caco-2 cell monolayers treated with TNF-α for 48 h. Time course (1)H-NMR-based metabonomics of the culture supernatant revealed markedly enhanced production of acetate after 12 hours of coincubation of B. bifidum and Caco-2. An increase in TER was observed by the administration of acetate to TNF-α-treated Caco-2 monolayers. Interestingly, acetate-induced TER-enhancing effect in the coculture of B. bifidum and Caco-2 cells depends on the differentiation stage of the intestinal epithelial cells. These results suggest that Bifidobacterium species enhance intestinal epithelial barrier function via metabolites such as acetate.

Effect of adalimumab on an enterocutaneous fistula in patients with Crohn's disease: a case series

Crohn's disease (CD) is characterized by transmural inflammation of the gastrointestinal tract, which predisposes patients to the formation of a fistula. The efficacy of adalimumab (ADA) for an enterocutaneous fistula remains unclear. In this report, we present a case series of 3 patients with enterocutaneous fistulizing CD treated with ADA. ADA treatment achieved sustained complete fistula closure in one patient. The other two cases, which failed to achieve fistula closure, had intestinal stenosis and were not receiving concomitant azathioprine. Combination therapy with ADA and azathioprine may be a useful option and an alternative to surgery for enterocutaneous fistulizing CD.

Adalimumab in Crohn's disease patients: pharmacokinetics in the first 6 months of treatment

BACKGROUND

Adalimumab is an effective therapy for Crohn's disease patients. However, there is limited knowledge on the pharmacokinetic properties of adalilumab in patients with Crohn's disease.

AIM

To assess the pharmacokinetic properties of adalilumab in a retrospective clinical cohort of patients with Crohn's disease, naïve to anti-tumour necrosis factor alpha therapy (anti-TNF).

METHODS

In a single tertiary centre, a clinical retrospective cohort was formed out of 76 patients with Crohn's disease who started adalilumab treatment (160/80/40EOW) between July 2007 and September 2010. We serially evaluated adalilumab serum levels at week 0, 12 and 28.

RESULTS

Patients were followed for a median time of 201 days (range 120-244) and received a median of 14 adalilumab injections (range 6-25). Adalilumab levels, although divergent between patients, were stable between week 12 and week 28. There was no correlation between adalilumab level and time since last administration (r = -0.061). In a multivariable regression analysis of patient factors influencing week 28 adalilumab levels, the regression model containing CRP at week 28 and BMI at baseline weakly but significantly predicted week 28 adalilumab levels (R(2) = 0.193, P = 0.004). Concomitant use of immunosuppressives was not a significant predictor (P = 0.304).

CONCLUSIONS

Intra-individual adalilumab levels seem very stable during the first 28 weeks of treatment, whereas inter-individual levels vary. Adalilumab levels appear stable over a 2-week period, as the time since last adalilumab administration did not affect the adalilumab level. CRP and BMI weakly predict week 28 adalilumab levels, whereas the use of immunosuppressives does not.

Cytokine patterns in experimental schistosomiasis mansoni infected mice treated with silymarin

The purpose of this study was to determine cytokine patterns in experimental schistosomiasis mansoni infected mice treated with silymarin. The study was conducted upon 100 mice that were divided into five groups; 20 each: uninfected control group, Schistosoma mansoni infected untreated mice (infected control), infected mice treated with praziquantel (PZQ), infected mice treated with silymarin and infected mice treated with both praziquantel and silymarin. 10 mice from each group were sacrificed at 10th and 18th weeks post infection respectively. Histopathological investigations were performed. Liver sections were stained with hematoxylin-eosin and Masson's trichrome stain to evaluate changes of granuloma sizes and numbers. Serum levels of the cytokines (TNF-α, IFN-γ, IL-4 and TGF-β1) were assessed in the sera of all groups by immunoassay. The measured levels of cytokines (IFN-γ, IL-4, TNF-α, TGF-β1) were found to be significantly increased in infected mice compared to normal control. At the same time, treated groups with silymarin alone or combined with PZQ showed significant decrease in IL-4, TNF-α and TGF-β1 levels compared to infected control. On the other hand, there was a significant increase in IFN-γ level observed in all treated groups compared to infected control. In addition, the histopathological examination of the liver in the group treated with PZQ showed a reduction in the number of livers eggs granuloma at all periods of sacrification compared with the infected untreated group. However, there was more decrease in granulomas diameter in both silymarin treated group or combined with PZQ at all periods of sacrification when compared to infected untreated group. In conclusion; treatment with silymarin combined with PZQ in murine schistosomiasis could reduce hepatic fibrosis by their action on the production of pro-inflammatory cytokines.

Incidence and predictors of clinical response, re-induction dose, and maintenance dose escalation with certolizumab pegol in Crohn's disease

BACKGROUND

Certolizumab pegol (CERT) is indicated for reducing the signs and symptoms of Crohn's disease (CD) and maintaining clinical response. Patients losing response received an extra "capture" re-induction dose in the PRECiSE 4 study. We examined the use of certolizumab in a retrospective cohort of patients with CD at a single inflammatory bowel disease center.

METHODS

We conducted a retrospective chart review of all adult patients with CD treated with CERT at the University of Chicago from April 22, 2008 to May 1, 2011. Demographics, disease characteristics, inflammatory bowel disease therapies, surgeries, CERT dosing, and clinical outcomes were recorded. Predictors of clinical response, re-induction dosing, and maintenance dose escalation were evaluated. Univariate, multivariate, and Kaplan-Meier analyses were performed for predictive variables of clinical response, re-induction dosing, and maintenance dose increases.

RESULTS

One hundred ten patients were identified; 23 were excluded. The remaining 87 patients had a sustained clinical response of 31.0%, remission of 14.9%, minimal or no response of 31.0%; 37.9% initially responded but lost response. In total, 35.6% of patients received a single re-induction dose of 400 mg after a mean of 29 weeks, predicted by prior anti-tumor necrosis factor (P = 0.007) and absence of perianal disease (P = 0.006); only 5 patients (16.1%) maintained a durable response or remission; 11.5% increased maintenance dosage after a mean of 50 weeks; all but 1 subsequently stopped CERT.

CONCLUSIONS

Some patients with CD (31%) achieved a sustained response. The majority of patients receiving re-induction dosing did not achieve a sustained clinical response. Previous treatment with anti-tumor necrosis factor therapy was associated with reduced responses, suggesting that CERT may be more effective as an initial anti-tumor necrosis factor therapy.

Total glucosides of peony attenuates 2,4,6-trinitrobenzene sulfonic acid/ethanol-induced colitis in rats through adjustment of TH1/TH2 cytokines polarization

The present study is to investigate effects of total glucosides of peony (TGP) on 2,4,6-trinitrobenzene sulfonic acid (TNBS)/ethanol-induced colitis in rats and to explore potential clinical use of TGP for treatment of inflammatory bowel disease. Sixty Sprague-Dawley rats were randomly grouped into normal controls, model controls, sulfasalazine (SASP) controls (100 mg/kg/day), and low, medium, and high-dose TGP groups (25, 50, and 100 mg/kg/day, respectively). 24 h following colonic instillation of TNBS, TGP, and SASP were given by gastric gavage three times a day for 7 days. Disease activity index (DAI), colon macroscopic damage index (CMDI), histopathological score (HPS), and myeloperoxidase (MPO) activity were evaluated. Levels of serum TNF-α, IL-1β, and IL-10 were measured by ELISA, and expression of TNF-α, IL-1β, and IL-10 mRNA and protein in colonic tissues was detected by RT-PCR and western blot, respectively. Compared with rats in the model controls, TGP (50 or 100 mg/kg/day)-treated rats with TNBS/ethanol-induced colitis showed significant improvements of DAI, CMDI, HPS, and MPO activity. Moreover, administration of TGP (50 or 100 mg/kg/day) decreased the up-regulated levels of serum TNF-α and IL-1β, and expression of TNF-α and IL-1β mRNA and protein in colonic tissues, and increased the serum IL-10 and colonic IL-10 mRNA and protein level. And there was no significant difference compared with administration of SASP (P > 0.05). TGP attenuates TNBS/ethanol-induced colitis in rats and its efficacy is similar to SASP, the potential mechanism might be related to the adjustment of Th1/Th2 cytokines polarization by decreasing pro-inflammatory cytokine TNF-α and IL-1β, and increasing anti-inflammatory cytokine IL-10.

MicroRNAs regulate tight junction proteins and modulate epithelial/endothelial barrier functions

Tightly controlled epithelial and endothelial barriers are a prerequisite for life as these barriers separate multicellular organisms from their environment and serve as first lines of defense. Barriers between neighboring epithelial cells are formed by multiple intercellular junctions including the ‘apical junctional complex—AJC’ with tight junctions (TJ), adherens junctions (AJ), and desmosomes. TJ consist of tetraspan transmembrane proteins like occludin, various claudins that directly control paracellular permeability, and the ‘Junctional Adhesion Molecules’ (JAMs). For establishing tight barriers TJ are essential but at the same time have to allow also selective permeability. For this, TJ need to be tightly regulated and controlled. This is organized by a variety of adaptor molecules, i.e., protein kinases, phosphatases and GTPases, which in turn are regulated and fine-tuned involving microRNAs (miRNAs). In this review we summarize available data on the role and targeting of miRNAs in the maintenance of epithelial and/or endothelial barriers.

EIS-based biosensor for ultra-sensitive detection of TNF-α from non-diluted human serum

Serum background is a critical issue for biosensor development as it interferes with the detection of target molecules and may give rise to false positive signal. We present here highly sensitive and selective TNF-α biosensor which is able to detect TNF-α from non-diluted human serum using magnetic bead coupled antibody and electrochemical impedance spectroscopy (EIS) techniques. The process is designed to detect TNF-α from human serum in three stages; (1) abundant protein backgrounds are depleted from the serum using magnetic bead coupled albumin and IgG antibodies, (2) after background depletion TNF-α is captured using magnetic bead coupled TNF-α antibody, and (3) the captured TNF-α is eluted from the magnetic beads and measured using EIS technique in which comb structured gold microelectrodes array (CSGM) is utilized to enhance the detection sensitivity. The system is able to achieve the limit of detection (LOD) at 1 pg/ml (57 fM) and a linear relationship between increasing TNF-α concentrations and charge-transfer resistance in a dynamic range of 1-1000 pg/ml.

The roles of genetic factors in uveitis and their clinical significance

BACKGROUND

Uveitis is a diverse group of intraocular inflammatory disease and is a significant cause of visual loss worldwide. Recent studies have identified various endogenous immune mechanisms and genetic factors that are involved in the pathogenesis of uveitis. This review provides an overview on the role of genetics in the development and clinical course of uveitis.

METHODS

PUBMED was used for literature search, and articles published from 1970 to 2012 that evaluated the genetic associations and mechanisms involved in the development and clinical features of uveitis were included.

RESULTS

Studies have demonstrated associations between various genetic factors and the development and clinical course of intraocular inflammatory conditions. Genes involved included genes expressing interleukins, chemokines, chemokine receptors, and tumor necrosis factor and genes involved in complement system, oxidation, and other intracellular molecular pathways.

CONCLUSION

Multiple genetic factors play important roles in the pathogenesis of uveitis and may influence the clinical course of uveitis. Further studies to investigate the genetic mechanisms of uveitis might identify additional genetic associations and might have the potential for identifying novel therapeutic targets in the treatment of intraocular inflammation.

Adalimumab Treatment in Biologically Naïve Crohn's Disease: Relationship with Ectopic MUC5AC Expression and Endoscopic Improvement

Background. Adalimumab (ADA) is effective for patients with Crohn's disease (CD). However, there have been few reports on ADA therapy with respect to its relationship with pathologic findings and drug efficacy in biologically naïve CD cases. Methods. Fifteen patients with active biologically naïve CD were treated with ADA. We examined them clinically and pathologically with ectopic MUC5AC expression in the lesions before and after 12 and 52 weeks of ADA therapy, retrospectively. Results. Both mean CD activity index scores and serum C-reactive protein values were significantly lower after ADA therapy (P < 0.001). In the MUC5AC negative group, all cases exhibited clinical remission (CR) and endoscopic improvement at 52 weeks. In MUC5AC positive groups, loss of MUC5AC expression was detected in cases having CR and endoscopic improvement at 52 weeks, while remnant ectopic MUC5AC expression was observed in those exhibiting no endoscopic improvement and flare up after 52 weeks. Conclusions. ADA leads to CR and endoscopic improvement in biologically naïve CD cases. In addition, ectopic MUC5AC expression may be a predictive marker of flare up and endoscopic improvement in the intestines of CD patients.

Concentrated grape juice (G8000™) reduces immunoexpression of iNOS, TNF-alpha, COX-2 and DNA damage on 2,4,6-trinitrobenzene sulfonic acid-induced-colitis

Inflammatory bowel disease (IBD) is a common chronic gastrointestinal disorder characterized by alternating periods of remission and active intestinal inflammation. Flavonoids exert several biological activities, which are mainly related to their ability to inhibit inflammatory process and/or to their antioxidant properties, and are able to regulate the immune response. The aim of this study was to evaluate whether phenolic compounds present in grape juice could reduce the inflammatory effects induced by experimental colitis. A total of 41 male Wistar rats were randomized into seven groups, as follows: G1--Sham group: sham induced-colitis rats; G2--(2,4,6-rinitrobenzenesulfonic acid) TNBS group: nontreated induced-colitis; G3--2% grape juice control group; G4--1% grape juice 24h after TNBS colitis induction; G5--1% grape juice on day 7 after colitis induction; G6--2% grape juice 24h after colitis induction; G7--2% grape juice on day 7 after colitis induction. Genotoxicity was evaluated by comet assay. Immunohistochemistry was determined using the streptavidin-biotin-peroxidase method being analyzed in control (normal tissue) and "hot spot" areas i.e., presenting inflammatory process being graded as 1 (weak), 2 (moderate), or 3 (strong). Both parameters were evaluated in the cytoplasm of epithelial or inflammatory cells. TNF-immunoexpression and iNOS were reduced after drinking grape juice 24 h or after 7 days for all doses tested. COX-2 was reduced in the groups exposed to 1% grape juice 24 h or 7 days of exposure. The grape juice at 1% dose in the last 7 days of treatment as well as grape juice at 2% dose decreased the peripheral blood genotoxicity. Taken together, the grape juice mainly at 1% dose exerts anti-inflammatory effects in chronic colitis caused by TNBS as a result of down regulation in the expression of pro-inflammatory cytokines and reduction of genotoxicity in peripheral blood cells.

MiR-874 promotes intestinal barrier dysfunction through targeting AQP3 following intestinal ischemic injury

Intestinal ischemic injury is a significant clinical problem arising from diseases or as a complication of abdominal surgery. Our previous study showed aquaporin 3 is involved in intestinal barrier impairment. Here, we revealed that intestinal ischemia induced a time-dependent increase of miR-874 expression and a time-dependent decrease of AQP3 expression, and the level of miR-874 expression was inversely related to AQP3 protein expression. In addition, miR-874 promoted the paracellular permeability in vitro through targeting 3'UTR of AQP3. Two of the tight junction proteins, Occludin and Claudin-1, were found to be involved in miR-874-induced intestinal barrier dysfunction.

Prednisolone but not infliximab aggravates the upregulated hepatic nitrogen elimination in patients with active inflammatory bowel disease

BACKGROUND

Catabolism and weight loss are serious problems in patients with active inflammatory bowel disease (IBD). The body nitrogen (N) depletion is partly related to increased hepatic capacity for the elimination of N through urea synthesis. This is probably caused by the inflammation per se, and the treatment with prednisolone may aggravate the problem, whereas the effect of biological therapy is unknown. Therefore, we examined the effects of prednisolone or infliximab on the regulation of urea synthesis in patients with active IBD.

METHODS

Urea synthesis was quantified by the functional hepatic nitrogen clearance (FHNC), i.e., the slope of the linear relationship between the urea nitrogen synthesis rate and the blood α-amino nitrogen concentration during alanine infusion. Thirty-seven patients with active IBD treated with either prednisolone or infliximab were examined before and after 7 days of treatment.

RESULTS

At baseline, the FHNC was similar in the 2 treatment groups (36 L/h). After 7 days, prednisolone increased the FHNC by 40% (55 L/h) (P = 0.03), whereas infliximab tended to reduce the FHNC by 15% (30 L/h) (P = 0.09). The changes in the FHNC differed significantly between the 2 treatment groups (P < 0.01).

CONCLUSIONS

Prednisolone treatment further upregulated urea synthesis, which increases the hepatic loss of nitrogen and promotes body catabolism. In contrast, infliximab treatment caused no such aggravation and likely reduced the N loss. These results may argue in favor of infliximab therapy for IBD and add to the pathophysiological understanding of the interplay between inflammation, catabolism, and anti-inflammatory treatment.

Analysis of the cytokine profile in the duodenal mucosa of refractory coeliac disease patients

This study shows that refractory coeliac disease-associated immune response is marked by a profile of cytokines, which differs from that in active coeliac disease. Moreover, it documents the clinical benefit of a neutralizing anti-TNF-α antibody in a patient with refractory coeliac disease.

Adalimumab: a review of its use in the treatment of patients with ulcerative colitis

Adalimumab is a fully human, recombinant, monoclonal IgG1 antibody specific for the cytokine tumor necrosis factor-α. It is approved for the treatment of patients with inflammatory diseases, including adults with moderately to severely active ulcerative colitis who are refractory to, or intolerant of, corticosteroids and/or immunomodulators. In two well-designed 8- and 52-week clinical trials in patients with moderately to severely active ulcerative colitis despite treatment with corticosteroids and/or immunomodulators, subcutaneous adalimumab (160 mg, week 0; 80 mg, week 2; 40 mg every other week starting at week 4) was more effective than placebo for inducing and maintaining clinical remission. A statistically significant effect size (albeit <10 %) over placebo for the remission per Mayo score (primary endpoint) was observed with adalimumab at 8 weeks in both trials and at 52 weeks in one trial. Compared with placebo, adalimumab was associated with reductions in hospitalizations and improvements in other secondary endpoints, including clinical response, mucosal healing, corticosteroid-sparing, and health-related quality of life measures. Additionally, an early response to adalimumab was shown to be predictive of long-term efficacy. Adalimumab was generally well tolerated, compared with placebo, during clinical trials in patients with ulcerative colitis; the adverse event profile was similar to that in patients with Crohn's disease or other approved indications. Adalimumab provides a new treatment option for patients with moderately to severely active ulcerative colitis who are refractory to, or intolerant of, corticosteroids and/or immunomodulators.

Excessive weight gain is associated with an increased risk for pouch failure in patients with restorative proctocolectomy

BACKGROUND

The aim was to evaluate the impact of weight gain on pouch outcomes after ileostomy closure.

METHODS

Consecutive inflammatory bowel disease patients with ileal pouches followed up at our subspecialty Pouch Center from 2002 to 2011 were studied. The association of excessive weight gain (defined as a 15% increase the index weight) with pouch outcomes were evaluated using univariate and multivariate analyses.

RESULTS

A total of 846 patients met inclusion criteria, with 470 (55.6%) being men. The mean age at the diagnosis of inflammatory bowel disease and at pouch surgery was 27.2 ± 11.9 years and 37.8 ± 12.8 years, respectively. Patients with weight gain more likely had mechanical or surgical complications of the pouch (18.4% versus 12.3%, P = 0.049), Crohn's disease of the pouch (30.6% versus 18.5%, P = 0.001), Pouch Center visits (2.0 [1.0-4.0] versus 2.0 [1.0-3.0], P = 0.008), and postoperative pouch-related hospitalization (21.1% versus 10.6%, P < 0.001). After a median follow-up of 9.0 (interquartile range = 4.0-14.0) years, 68 patients (8.0%) developed pouch failure. In the multivariate analysis, excessive weight gain was an independent risk factor for pouch failure with a hazard ratio of 1.69 (95% confidence interval = 1.01-2.84, P = 0.048) after adjusting for preoperative or postoperative use of anti-tumor necrosis factor biologics, postoperative use of immunosuppressants, Crohn's disease of the pouch, mechanical or surgical complications of the pouch, and postoperative pouch-associated hospitalization.

CONCLUSIONS

Excessive weight gain after closure of the ileostomy is associated with worse pouch outcomes in patients with inflammatory bowel disease. Appropriate weight control may help improve pouch retention.

Adalimumab treatment in Crohn's disease: an overview of long-term efficacy and safety in light of the EXTEND trial

The advent of anti-tumor necrosis factor (TNF) therapies revolutionized the treatment of inflammatory bowel disease. Adalimumab is a subcutaneous anti-TNF agent indicated for use in patients with moderate-to-severe Crohn’s disease and those with moderate-to-severe ulcerative colitis. In both diseases, it can be used for both induction of remission and for maintenance of remission. This review focuses on its use in Crohn’s disease as described in the EXTEND (Extend the Safety and Efficacy of Adalimumab through Endoscopic Healing) trial. Several clinical trials using traditional instruments to measure clinical response have had endoscopic substudies looking for endoscopic healing. The EXTEND trial is the first to use mucosal healing on endoscopy as a primary endpoint for patients with moderate-to-severe Crohn’s disease and baseline ulcerative disease treated with continuous adalimumab. In this well designed trial, the primary endpoint was narrowly missed, but the secondary endpoints further the notion that mucosal healing should be a more mainstream measure of drug efficacy. How this will translate from clinical trials to the clinic is not yet clear, but identifying noninvasive markers for mucosal healing, and understanding the implications of mucosal healing for safety, resource utilization, and quality of life are all worthy targets for further study. The aim of this review is to understand the role of mucosal healing, safety profile, and efficacy in patients treated with anti-TNF therapy, with particular attention to adalimumab and the EXTEND trial.

Beneficial role of the probiotic mixture Ultrabiotique on maintaining the integrity of intestinal mucosal barrier in DSS-induced experimental colitis

The etiology of inflammatory bowel diseases which include ulcerative colitis (UC) and Crohn disease has not yet been clarified. Several hypotheses suggest a change in composition of gut microflora along with an impaired mucosal barrier that lead to excessive mucosal immunologic responses. Increased production of nitric oxide (NO) contributes greatly to the tissue injury caused by chronic inflammation. Evidence indicates that the mucus layer covering the epithelium is altered during UC and experimental colitis. Our aim in this study was to investigate the potential therapeutic effect of probiotic during DSS-induced colitis by modulating the immune system and colonic mucus production. For that purpose, the probiotic formulation Ultrabiotique(®) (Lactobacillus acidophilus, Bifidobacterium lactis, Lactobacillus plantarum and Bifidobacterium breve) was administered daily for 7 d to mice with colitis. Probiotic supplementation improved clinical symptoms and histological alterations observed during DSS induced colitis. Ultrabiotique(®) treatment down regulated the NO production by peritoneal macrophages of DSS-treated mice and enhanced mucus production in both DSS-treated and healthy mice. In conclusion, the modification of microflora by the Ultrabiotique(®) played a beneficial role in maintaining the integrity of the intestinal mucosal barrier and promoted tissue repair.

Serum adalimumab concentration and clinical remission in patients with Crohn's disease

BACKGROUND

Drug concentration monitoring may be useful to guide therapeutic adjustments for anti-tumor necrosis factor agents in Crohn's disease. The relationship between serum adalimumab concentrations and clinical outcomes was assessed using data from CLinical Assessment of Adalimumab Safety and Efficacy Studied as Induction Therapy in Crohn's Disease (CLASSIC) I/II.

METHODS

Serum adalimumab concentrations at week 4 of CLASSIC I and weeks 4, 24, and 56 of CLASSIC II were compared by clinical remission status (yes/no). Logistic regression and Classification and Regression Tree analyses explored factors associated with remission at weeks 4, 24, and 56. Threshold analyses and receiver operating characteristic curves evaluated the relationship between serum concentrations and clinical remission/response.

RESULTS

Serum adalimumab concentrations for 275 patients were available. Median adalimumab concentrations were significantly higher in patients who achieved clinical remission than those who did not at week 4 of CLASSIC I (8.10 versus 5.05 µg/mL, P < 0.05). At all time points, adalimumab concentrations demonstrated considerable variability and overlap between patients with and without remission. With Classification and Regression Tree analyses, baseline Crohn's Disease Activity Index, baseline C-reactive protein, and adalimumab concentrations were associated with early remission at week 4 of CLASSIC I and week 4 of CLASSIC II, but not at weeks 24 and 56. Receiver operating characteristic curves demonstrated low utility of cutoff thresholds to discriminate by clinical response/remission status.

CONCLUSIONS

A positive association between serum adalimumab concentration and remission was identified at several time points. A threshold concentration reliably associated with remission was not identified. Further prospective evaluations are needed before recommendations for adalimumab concentration monitoring can be made.

Colon Mucosa Exhibits Loss of Ectopic MUC5AC Expression in Patients with Ulcerative Colitis Treated with Oral Tacrolimus

Background. Tacrolimus (FK506) is effective for patients with ulcerative colitis (UC). However, there are few reports on tacrolimus therapy (TT) with respect to the relationship with endoscopic and clinicopathologic findings. Methods. Thirty patients with moderate/severe active UC refractory to or dependent on corticosteroid were treated with oral tacrolimus. The expression of ectopic MUC5AC in the colon was pathologically analyzed before and at 12 weeks after TT, evaluating the Mayo score and steroid-sparing effects. Results. Both mean disease and endoscopic activity index scores were reduced at levels of statistical significance in 26 UC patients receiving more than one month of TT (P < 0.0001). The dose of prednisolone was reduced by a statistically significant amount (P = 0.00022), and 14 of the 26 patients (53.8%) had steroid-free status 12 weeks after TT. The decrease in ectopic MUC5AC expression in the mucous cells of the colon was significantly associated with endoscopic improvement of inflammation in the UC patients with TT (P = 0.043). Loss of ectopic MUC5AC expression was detected in all patients who had complete response. Conclusions. Tacrolimus appears to be effective for the treatment of moderate/severe UC patients. Loss of ectopic MUC5AC expression may be important for pathologic remission in the colon of UC patients.

Clinical use of anti-TNF therapy and increased risk of infections

Biologics such as antitumor necrosis factor (anti-TNF) drugs have emerged as important agents in the treatment of many chronic inflammatory diseases, especially in cases refractory to conventional treatment modalities. However, opportunistic infections have become a major safety concern in patients on anti-TNF therapy, and physicians who utilize these agents must understand the increased risks of infection. A literature review of the published data on the risk of bacterial, viral, fungal, and parasitic infections associated with anti-TNF therapy was performed and the clinical presentation, diagnostic tests, management, and prevention of opportunistic infections in patients receiving anti-TNF therapy were reviewed. Awareness of the therapeutic potential and associated adverse events is necessary for maximizing therapeutic benefits while minimizing adverse effects from anti-TNF treatments. Patients should be adequately vaccinated when possible and closely monitored for early signs of infection. When serious infections occur, withdrawal of anti-TNF therapy may be necessary until the infection has been identified and properly treated.

Normalization of mucosal cytokine gene expression levels predicts long-term remission after discontinuation of anti-TNF therapy in Crohn's disease

OBJECTIVE

To investigate mucosal cytokine gene expression levels in healed mucosa after anti-tumor necrosis factor (TNF) therapy in patients with Crohn's disease (CD) as possible risk factors for relapse after discontinuation of therapy.

DESIGN

Thirty-seven CD patients treated with anti-TNF agents until complete mucosal healing, documented by endoscopy, discontinued anti-TNF treatment and entered a follow-up study. Levels of mRNA expression of interleukin (IL)17A (IL17A), IL23, interferon-gamma (IFNG), TNF-alpha (TNF), IL10 and Forkhead Box P3 (FOXP3) were measured in biopsies from healed mucosa and analyzed as possible risk factors of relapse. Mucosal cytokine transcript levels from patients without CD served as controls.

RESULTS

Patients were followed after therapy withdrawal until relapse. Median time to relapse was 20 and 68 weeks for patients with elevated and normalized IL17A and TNF expression levels, respectively (p = 0.02 for IL17A and p = 0.003 for TNF, log-rank). Expression levels of TNF, IL17A and FOXP3 were significantly higher in patients who relapsed before 26 weeks than in those who did not relapse, and also higher in patients with relapse before week 52 versus non-relapsers. Elevated expression levels of TNF and IL17A in healed mucosa significantly increased the risk of relapse (HR = 3.4, p = 0.03, sensitivity 80%, specificity 38% and HR = 4.1, p = 0.008, sensitivity 81%, specificity 61%, respectively).

CONCLUSIONS

Normalization of mucosal gene expression of cytokines after anti-TNF therapy does not occur in all patients with healed mucosa as judged by endoscopy. Normalization of TNF and/or IL17A expression predicts long-term remission.

The possible mechanisms of Picrasma quassiodes (D. Don) Benn. in the treatment of colitis induced by 2,4,6-trinitrobenzene sulfonic acid in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Picrasma quassiodes (D. Don) Benn.(PQB) is used in folk medicines for the treatment of colds, upper respiratory infection, acute tonsillitis, acute gastroenteritis, bacillary dysentery and a variety of acute infectious diseases in Asia. Although recent reports indicate that PQB has antibacterial, and anti-inflammatory effects, its effects on colitis and its inhibitory mechanisms have not been previously reported.

AIM OF THE STUDY

To assess the effects and the mode of action of the extract of Picrasma quassiodes (D. Don) Benn.(PQB) on a model of colitis in mice induced by trinitrobenzene sulfonic acid (TNBS).

MATERIALS AND METHODS

We induced mice colitis using TNBS/ethanol, then different doses of Picrasma quassiodes (D. Don) Benn.(PQB) extract (100, 200 and 400 mg/kg/day) and sulfasalazine (500 mg/kg/day) were administered by gavage for 7 days after the induction of colitis. The mice body weight, colonic wet weight, colonic lengths, myeloperoxidase (MPO) activity, macroscopic and histological colon injury were observed. Pro-inflammatory cytokines such as: tumor necrosis factor-alpha (TNF-α) and interleukin-8 (IL-8) were assayed by enzyme-linked immunoassay. The protein expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in the colons were determined by immunohistochemical analysis.

RESULTS

PQB administration effectively prevented mice diarrhea, decreasing of the body weights, shortening of colon length and increasing of colon wet weight. Macroscopic and histological examinations also indicated that it was protected against colonic edema, ulceration and MPO activity elevation. Furthermore, PQB inhibited the abnormal secretions of pro-inflammatory cytokines, such as TNF-α and IL-8. Additionally, administration of PQB effectively inhibited COX-2 and iNOS protein expression.

CONCLUSIONS

These results suggest that PQB has an anti-inflammatory effect on TNBS-induced colitis due to the down-regulations of the productions and expressions of inflammatory mediators, and that it may be a potential inflammatory bowel disease (IBD) drug candidate.

Protective effect of sanguinarine against acetic acid-induced ulcerative colitis in mice

The quaternary ammonium salt, sanguinarine (SANG), is of great practical and research interest because of its pronounced, widespread physiological effects, which promote anti-microbial and anti-inflammatory responses in experimental animals. Although SANG is originally shown to possess anti-inflammatory properties and it has been used to treat various inflammatory diseases, its effects on ulcerative colitis have not been previously explored. The aim of the present study is to evaluate the effect of SANG on acetic acid-induced ulcerative colitis in mice. Experimental animals received SANG (1, 5 and 10 mg/kg, p.o.) and sulfasalazine (500 mg/kg, p.o.) for seven consecutive days after induction of colitis by intra-rectal acetic acid (5% v/v) administration. The colonic mucosal injury was assessed by clinical, macroscopic, biochemical and histopathological examinations. SANG treatment significantly decreased mortality rate, body weight loss, disease activity index (DAI), wet colon weight, macroscopic and histological score when compared to acetic acid-induced controls. In addition, administration of SANG effectively inhibited p65 NF-κB protein expression and MPO activity accumulation. The levels of TNF-α and IL-6 in the serum and colon tissue of mice with experimental colitis were decreased by SANG in a concentration-dependent manner in response to p65 NF-κB. The possible mechanism of protection on experimental colitis was that SANG could be through attenuating early steps of inflammation as well as decreasing the expression of NF-κB and subsequent pro-inflammatory cytokines production.

Maintenance of the remission stage of Crohn's disease with adalimumab therapy during pregnancy

A 25-year-old pregnant woman complained of abdominal pain and diarrhea. Total colonoscopy provided a diagnosis of Crohn's disease (CD) of the large intestine (Crohn's colitis). Because the patient was allergic to mesalazine, adalimumab (ADA) was used as maintenance therapy during pregnancy, following prednisolone as remission induction therapy. Remission of the patient's CD was maintained with ADA, and the patient delivered a baby girl without any difficulties. Remission of the patient's CD continued to be maintained with the administration of ADA after childbirth. We believe that this is the first report of the use of ADA therapy in a pregnant CD patient in Japan.

Comparative effectiveness of anti-TNF agents for Crohn's disease in a tertiary referral IBD practice

BACKGROUND

The three Food and Drug Administration (FDA)-approved anti-tumor necrosis factor drugs (anti-TNFs) for Crohn's disease (CD) have not been directly compared.

AIM

To compare the efficacy of the three anti-TNFs for CD in clinical practice.

METHODS

Retrospective review of patients initiated on anti-TNF between 2004 and 2008. Disease activity, quality of life, and remission rates were compared between groups over 1 year.

RESULTS

Sixty patients with CD were initiated on anti-TNF from 2004 to 2008: 31 on infliximab (IFX) and 29 on adalimumab (ADA) or certolizumab pegol (CTZ). More patients in the ADA/CTZ scores group had prior exposure to anti-TNF (76 versus 10%, p < 0.01). Mean Harvey-Bradshaw Index (HBI) scores in the IFX group were lower than in the ADA/CTZ group at 12 months (2.72 ± 3.34 versus 5.63 ± 5.33, p = 0.03). At 12 months, more IFX patients were in remission compared with those on ADA/CTZ (88 versus 53%, p ≤ 0.01). Mean short inflammatory bowel disease questionnaire (SIBDQ) scores were not different between the IFX and ADA/CTZ groups at 12 months. Stratified analyses and logistic regression based on prior anti-TNF use did not show differences in remission rates at any time point post-baseline between groups.

CONCLUSIONS

After adjustment for prior anti-TNF there was no difference in remission rates between the IFX and ADA/CTZ groups at any time point post-baseline. This suggests that differences between groups were accounted for by a higher rate of prior anti-TNF in the ADA/CTZ group. Our results should be reviewed with caution given the small sample size.

Anti-TNF therapy is associated with decreased imaging and radiation exposure in patients with Crohn's disease

BACKGROUND

Diagnostic imaging is frequently used in Crohn's disease (CD) for diagnosis, evaluation of complications, and determination of response to treatment. Patients with CD are at risk for high radiation exposure in their lifetime. The aim of our study was to compare the effective dose of radiation in CD patients the year prior to and the year after initiation of anti-tumor necrosis factor (anti-TNF) agents or corticosteroids.

METHODS

We conducted a retrospective review of 99 CD patients initiated on anti-TNF therapy or corticosteroids between 2004 and 2009 in a tertiary care center.

RESULTS

Sixty-five patients were initiated on anti-TNF agents and 34 were initiated on corticosteroids. The anti-TNF cohort was significantly younger at diagnosis and at the time of initiation of anti-TNF or steroid therapy. The anti-TNF group had significantly more stricturing, penetrating, and perianal disease than the corticosteroid group. The anti-TNF cohort had a significant reduction in number of radiologic exams (5.5 vs. 3.7, P < 0.01) as well as a significant reduction in the cumulative radiation dose (28.1 vs. 15.0 mSv, P < 0.01) the year after initiation of therapy. This reduction was largely attributable to decreased use of computed tomography (CT) scans. In contrast, there was no significant change in radiation exposure in the corticosteroid cohort. Logistic regression analysis showed a strong trend toward higher exposure in patients with complicated disease behavior (stricturing or penetrating phenotype) (odds ratio [OR] 2.87, 95% confidence interval [CI] 0.98-8.38).

CONCLUSIONS

Initiation of anti-TNF therapy for treatment of CD is associated with a significant reduction in diagnostic radiation exposure. Conversely, steroid treatment does not reduce diagnostic radiation exposure.

Role of TLR4/NF-κB in damage to intestinal mucosa barrier function and bacterial translocation in rats exposed to hypoxia

The role of Toll-like receptor 4 (TLR4)/nuclear factor-kappa-B (NF-κB) in intestinal mucosal barrier damage and bacterial translocation under hypoxic exposure is unclear. Here, we investigated their role using an acute hypobaric hypoxia model. Adult Sprague-Dawley rats were divided into control (C), hypoxia (H), hypoxia+NF-κB inhibitor pyrrolidinedithiocarbamic acid (PDTC) (100 mg. kg) (HP), hypoxia+0.5 mg/kg lipopolysaccharide (HPL), and hypoxia+PDTC+LPS (HPL) group. Except control group, other four groups were placed in a hypobaric chamber set at 7000 m. Samples were collected at 72 h after pressure reduction. Damage in ultrastructure of the intestinal tract was examined by transmission electron microscopy and bacterial translocation was detected by cultivation. Kinetic turbidimetric assay was used to measure the serum LPS.

ELISA was performed to detect TNF-α and IL-6 serum concentrations. Fluorescent quantitative RT-PCR was used to measure TLR4 mRNA levels was measured using quantitative RT-PCR and protein of NF-κB p65 was measured by western blotting. Different degrees of intestinal mucosa damage were observed in groups H and HL. The damage was significantly alleviated after blockage of the TLR4/NF-κB signaling pathway. PDTC- treatment also reversed hyoxia- and LPS-induced bacterial translocation rate and increased serum levels of LPS, TNF-α, and IL-6. TLR4 mRNA levels and NF-κB p65 expression were consistent with the serum factor results. This study suggested that TLR4 and NF-κB expression increased in rat intestinal tissues after acute hypoxia exposure. PDTC-treatment reversed TLR4 and NF-κB upregulation and alleviated damage to the intestinal tract and bacterial translocation. Thus, the TLR4/NF-κB signaling pathway may be critical to the mechanism underlying hypoxia-induced damage to intestinal barrier function and bacterial translocation.

Experimental human endotoxemia: a model of the systemic inflammatory response syndrome?

BACKGROUND

The normal human intravenous endotoxin model has been used for more than 50 years. It was once considered a possible model of sepsis, but, because no infection is present, it is better described as a model of systemic inflammation. We demonstrate herein that at least three of four systemic inflammatory response syndrome (SIRS) criteria are achieved with the model.

METHODS

Otherwise healthy human volunteers were given Escherichia coli endotoxin 2 ng/kg intravenously. Vital signs were monitored, and blood samples were collected over time for assessment of white blood cells (WBCs), cytokines, counter-regulatory hormones, and monocyte receptors.

RESULTS

The means of three variables (core temperature, heart rate, WBC) met the SIRS criteria. Compared with baseline, cytokines were elevated acutely, with tumor necrosis factor-alpha (TNFα) exhibiting temporal primacy over the other cytokines. Counter-regulatory hormones (cortisol, epinephrine) also were elevated acutely. Finally, the monocyte cell-surface receptors cluster of differentiation molecule (CD) 11b and TNF receptor-II were elevated and decreased, respectively.

CONCLUSIONS

The experimental human endotoxin model satisfies SIRS criteria and probably is best described as a model of Toll-like receptor 4 agonist-induced systemic inflammation.

The effect of adalimumab for induction of endoscopic healing and normalization of mucosal cytokine gene expression in Crohn's disease

OBJECTIVE

To investigate the effects of adalimumab on the induction of complete endoscopic healing and normalization of mucosal cytokine gene expression in patients with active Crohn's disease.

MATERIAL AND METHODS

A prospective, single-center study including 77 patients. All were examined by endoscopy before initiation of adalimumab induction therapy with a minimum of six adalimumab injections. Patients were treated until documentation of complete endoscopic healing. Biopsies for measurements of mRNA expression levels of interleukin(IL)-17A (IL17A), IL23, interferon-gamma (IFNG), tumor necrosis factor-alpha (TNF), IL10 and Forkhead Box P3 (FOXP3), as well as for immunohistochemistry (IHC) were sampled at pre- and post-treatment endoscopy, and from 17 control patients.

RESULTS

Complete endoscopic healing was achieved in 27.3% after 10 weeks of treatment, documented by endoscopy at week 12. Cumulative endoscopic healing after 52 weeks was 44.2%. Complete endoscopic healing led to a significant reduction in mRNA expression levels for all cytokines except IL10. Elevated expression of TNF and IL-17A persisted in 52% and 76%, respectively, of patients with complete endoscopic remission. Pre-treatment cytokine gene expression levels did not predict response to adalimumab therapy.

CONCLUSIONS

Adalimumab induces accumulated complete endoscopic healing in 44% of patients after 52 weeks of therapy. Normalization of mucosal gene expression of cytokines does not occur in all patients with endoscopy-verified healed mucosa. Inclusion of normalized mucosal cytokine expression into the concept of mucosal healing could have an impact on long-term clinical outcome.

Infliximab and surgical treatment of complex anal Crohn's disease

AIM

Perianal fistulae in Crohn's disease are frequently complex, involve the anal sphincter complex and surgical treatment can be associated with poor healing of wounds and damage to the mechanism of continence. The aim of this study was to evaluate the efficacy and duration of response to infliximab in the long-term management of perianal fistulae in Crohn's disease in routine clinical practice.

METHOD

A prospectively maintained database was used to identify patients with Crohn's disease and complex anal fistulae who were treated with infliximab (primary treatment, three initial infusions followed by maintenance therapy). Patients who received infliximab for luminal disease or for enterocutaneous, peristomal or rectovaginal fistulae were excluded from this study.

RESULTS

Fifty-two patients [25 male, median age 24 (range 15-72) years] were treated with infliximab for perianal Crohn's fistulae for a median of 66 (7-124) months. Twenty-six of the patients underwent pre-infliximab MRI scans and 38 had an examination under anaesthetic (EUA) prior to commencement of treatment, 22 of whom had seton(s) inserted into their fistulae. Maintenance therapy was possible in 42 (81%) of 52 patients. Twenty-two (42.3%) patients had a complete response to treatment, 23 (44.2%) had a partial response and 7 (13.5%) had no response. Less than complete response to infliximab was associated with a greater risk of requiring surgical intervention (Fisher's exact test, d.f. 1, P = 0.005).

CONCLUSION

The response rates of Crohn's related complex perianal fistulae to infliximab are good. Complete response is associated with a reduced need for surgical intervention.

Systematic assessment of factors influencing preferences of Crohn's disease patients in selecting an anti-tumor necrosis factor agent (CHOOSE TNF TRIAL)

BACKGROUND

Infliximab (IFX), adalimumab (ADA), and certolizumab pegol (CZP) have similar efficacy in induction and maintenance of clinical remission in Crohn's disease (CD). Given the comparable nature of these drugs, patient preferences may influence the choice of the product. We aimed to identify factors that may contribute to CD patients' decision in selecting one anti-tumor necrosis factor (TNF) agent over the others.

METHODS

A prospective survey was performed among anti-TNF-naïve CD patients. Prior to completion of a questionnaire, patients were provided with a written description of the three anti-TNF agents, focusing on indications, mode of administration, side effects, and scientific evidence of efficacy and safety for each drug.

RESULTS

One hundred patients (47 females, mean age 45 ± 16 years, range 19-81) with an ileal, colonic, or ileocolonic (33%, 40%, and 27%, respectively) disease location completed the questionnaire. Based on the information provided, 36% of patients preferred ADA, 28% CZP, and 25% IFX, whereas 11% were undecided. The patients' decision in selecting a specific anti-TNF drug was influenced by the following factors: ease of use (69%), time required for therapy (34%), time interval between application of the drug (31%), scientific evidence for efficacy (19%), and fear of syringes (10%).

CONCLUSIONS

The majority of patients preferred anti-TNF medications that were administered by subcutaneous injection rather than by intravenous infusion. Ease of use and time required for therapy were two major factors influencing the patients' selection of a specific anti-TNF drug. Patients' individual preferences should be taken into account when prescribing anti-TNF drugs.

Adalimumab therapy following granulocyte and monocyte adsorptive apheresis in a patient with Crohn's disease accompanied by chronic myeloid leukemia

A 52-year-old woman was diagnosed with Crohn's disease (CD) of the large intestine in May 2001. Her disease was accompanied by the development of chronic myelogenous leukemia (CML) in December 2003. Remission of her CML has been maintained up to the present with tyrosine kinase inhibitors. Clinical and endoscopic remission of the patient's CD was maintained with salazosulfapyridine (3000 mg/day) and occasional prednisolone (≤20 mg/day) from 2001 to 2010. However, in December 2010 the patient complained of abdominal pain and diarrhea more than 10 times a day. Endoscopy showed serpiginous (snake-like) ulcers in the transverse colon and aphthous ulcers in the sigmoid colon. Intensive granulocyte and monocyte adsorptive apheresis (GMA) (two sessions per week, total of ten sessions) was performed, and the CD activity index (CDAI) decreased from 259 to 175. Six adalimumab injections were administered to improve the remaining inflammatory mucosa. Two months after induction therapy with adalimumab, the CDAI decreased from 175 to 107 without side effects. Endoscopy revealed mucosal healing of the colonic inflammatory lesions. We experienced a case of a patient with CD accompanied by CML. We successfully treated the patient by a combination of intensive GMA and adalimumab.

Efficacy and safety of infliximab and adalimumab in Crohn's disease: a single centre study

BACKGROUND

Infliximab and adalimumab are highly effective in Crohn's Disease (CD). This is supported by clinical trials and open-label studies using either infliximab or adalimumab, thus not allowing a proper comparison between these anti-TNFs in CD.

AIM

To evaluate the efficacy and safety of infliximab and adalimumab in active CD.

METHODS

In a longitudinal study, CD patients with indication for anti-TNFs were treated with infliximab or adalimumab.

RESULTS

Ninety-three patients were treated with infliximab (n = 44) or adalimumab (n = 49). In the infliximab group, the induction was completed by 77.3% of patients, due to no response (n = 2), delayed hypersensitivity reactions (DHR) or infusion reactions (n = 8). Maintenance with infliximab was completed by 60% of patients, due to clinical worsening or loss of efficacy (n = 5), DHR or infusion reactions (n = 5). In the adalimumab group, all patients completed the induction, while maintenance was completed by 67% of patients, due to clinical worsening or loss of efficacy (n = 8), DHR (n = 1), other causes (n = 7). In both groups, the CDAI significantly reduced at baseline vs. each visit (P < 0.04). The Kaplan-Meier survival analysis performed to evaluate the risk of steroid-free remission in patients treated with infliximab vs. adalimumab detected no differences (log-rank test P = 0.4). Cox proportional-hazards regression identified two predictors of steroid-free remission using anti-TNFs: no smokers [HR = 2.94 (1.52-5.70), P = 0.001] and non stricturing non penetrating behaviour [HR = 3.116 (1.06-9.13), P = 0.03826].

CONCLUSIONS

Infliximab and adalimumab showed a similar efficacy. No smoking and non-stricturing non-penetrating behaviour were predictors of steroid-free remission.

Mechanisms of tumor necrosis factor-alpha-induced leaks in intestine epithelial barrier

PURPOSE

The aim of this study was to investigate the signaling mechanisms surrounding changes in tight junction (TJ) and the permeability of human intestinal epithelial cell induced by tumor necrosis factor-alpha (TNF-α).

METHODS

To confirm that TNF-α induces epithelial barrier hyperpermeability by disrupting tight junction, Caco-2 cells were exposed to TNF-α, and changes in epithelial permeability (via TER assay), F-actin dynamics (via Rhodamine-phalloidin staining) and tight junction protein expression (via western blot) were monitored. Moreover, to ensure that NF-κB participated in the regulatory mechanisms, Caco-2 cells were transfected with DNMu-IκBα or control plasmids, the above experiments were repeated and the activation effect of TNF-α on NF-κB was detected by luciferase reporter assays. Lastly, we took dominant negative plasmid and knockdown approaches to investigate the potential importance of the NF-κB/myosin light chain kinase (MLCK)/myosin light chain phosphorylation (pMLC) pathways in TNF-a-mediated damage.

RESULT

TNF-α could cause NF-κB activation, F-actin rearrangement, tight junction disruption and barrier dysfunction. These effects were alleviated by inhibiting NF-κB. TNF-α induced increase of MLCK transcription and MLC phosphorylation act later than NF-κB activation, which could be suppressed both by inactivating and deleting NF-κB.

CONCLUSIONS

TNF-α induces intestinal epithelial cell hyperpermeability by disrupting TJs, in part through MLCK upregulation, in which NF-κB is the positive upstream regulator for MLCK.

TNF-Alpha in the Locomotor System beyond Joints: High Degree of Involvement in Myositis in a Rabbit Model

The importance of TNF-alpha in arthritis is well documented. It may be that TNF-alpha is also markedly involved in muscle inflammation (myositis). An animal model where this can be investigated is needed. A newly developed rabbit myositis model involving pronounced muscle overuse and local injections of substances having proinflammatory effects was therefore used in the present study. The aim was to investigate the patterns of TNF-alpha expression in the developing myositis and to evaluate the usefulness of this myositis model for further TNF-alpha research. Human rheumatoid arthritis (RA) synovial tissue was examined as a reference. TNF-alpha immunoexpression and TNF-alpha mRNA, visualized via in situ hybridization, were detected in cells in the inflammatory infiltrates of the affected muscle (soleus muscle). Coexistence of TNF-alpha and CD68 immunoreactions was noted, suggesting that the TNF-alpha reactive cells are macrophages. Expression of TNF-alpha mRNA was also noted in muscle fibers and blood vessel walls in areas with inflammation. These findings demonstrate that TNF-alpha is highly involved in the myositis process. The model can be used in further studies evaluating the importance of TNF-alpha in developing myositis.

Genetic and genomic predictors of anti-TNF response

The introduction of anti-TNF therapy has dramatically improved the outlook for patients suffering from a number of inflammatory conditions including rheumatoid arthritis and inflammatory bowel disease. Despite this, a substantial proportion of patients (approximately 30-40%) fail to respond to these potentially toxic and expensive therapies. Treatment response is likely to be multifactorial; however, variation in genes or their expression may identify those most likely to respond. By targeted testing of variants within candidate genes, potential predictors of anti-TNF response have been reported; however, very few markers have replicated consistently between studies. Emerging genome-wide association studies suggest that there may be a number of genes with modest effects on treatment response rather than a few genes of large effect. Other potential serum biomarkers of response have also been explored including cytokines and autoantibodies, with antibodies developing to the anti-TNF drugs themselves being correlated with treatment failure.

Biomarkers of Therapeutic Response in the IL-23 Pathway in Inflammatory Bowel Disease

OBJECTIVES:

Interleukin-23 (IL-23) has emerged as a new therapeutic target for the treatment of inflammatory bowel disease (IBD). As biomarkers of disease state and treatment efficacy are becoming increasingly important in drug development, we sought to identify efficacy biomarkers for anti-IL-23 therapy in Crohn's disease (CD).

METHODS:

Candidate IL-23 biomarkers, downstream of IL-23 signaling, were identified using shotgun proteomic analysis of feces and colon lavages obtained from a short-term mouse IBD model (anti-CD40 Rag2^−/−) treated preventively with monoclonal antibodies (mAbs) to the IL-23 receptor (IL-23R). The biomarkers were then measured in an IBD T-cell transfer model treated therapeutically with a mAb to IL-23 (p19), confirming their association with IBD. To assess the clinical relevance of these markers, we assessed their concentrations in clinical serum, colon tissue, and feces from CD patients.

RESULTS:

We identified 57 proteins up or downregulated in diseased animals that returned to control values when the mice were treated with mAbs to IL-23R. Among those, S100A8, S100A9, regenerating protein 3β (REG), REG3γ, lipocalin 2 (LCN2), deleted in malignant tumor 1 (DMBT1), and macrophage migration inhibitory factor (MIF) mRNA levels correlated with disease score and dose titration of mAbs to IL-23R or IL-23(p19). All biomarkers, except DMBT1, were also downregulated after therapeutic administration of mAbs to IL-23(p19) in a T-cell transfer IBD mouse model. In sera from CD patients, we confirmed a significant upregulation of S100A8/A9 (43%), MIF (138%), pancreatitis-associated protein (PAP, human homolog of REG3β/γ 49%), LCN2 (520%), and CCL20 (1280%), compared with control samples, as well as a significant upregulation of S100A8/A9 (887%), PAP (401%), and LCN2 (783%) in human feces from CD patients compared with normal controls.

CONCLUSIONS:

These studies identify multiple protein biomarkers downstream of IL-23 that could be valuable tools to assess the efficacy of this new therapeutic agent.