The key role of macrophages in the immunopathogenesis of inflammatory bowel disease

Clophosome alleviate dextran sulphate sodium-induced colitis by regulating gut immune responses and maintaining intestinal integrity in mice

Inflammatory bowel disease (IBD) is a chronic progressive disorder characterized by complicated gastrointestinal inflammation. Research on therapeutic agents is still urgent due to the lack of satisfactory treatments. Gut macrophages are considered to be predominant in excessive inflammatory responses. Thus, we aimed to investigate whether depletion of macrophages would have a beneficial effect on IBD and could be a potential therapeutic strategy. In this study, we established a 12-day Dextran sodium sulphate (DSS)-induced colitis mouse model and determined the effect of the macrophage depletion agent Clophosome (neutral clodronate liposomes; CNC). The results showed that CNC significantly alleviated the symptoms of colitis, as demonstrated by greater weight gain, decreased disease activity index (DAI) scores, and lower histopathological damage scores, as well was reduced levels of the proinflammatory cytokines interleukin (IL)-6 and tumour necrosis factor (TNF)-α. To investigate T cell subsets, cells were isolated from the lamina propria and cultured to analyse the expression of IL-17A, interferon (IFN)-γ and Foxp3 in CD4+ cells by flow cytometry. The data showed that during the process of colitis, the frequencies of CD4+ IL-17A+ T cells were significantly increased. Notably, CNC treatment markedly reduced the population of CD4+ IL-17A+ T cells, especially CD4+ IL-17A+ IFN-γ+ T cells. Furthermore, intestinal barrier integrity, as assessed by immunostaining of mucin and tight junction proteins, was severely disrupted in colitis. CNC improved the intestinal barrier by enhancing the expression of muc-2 and occludin. In summary, our findings demonstrated that CNC successfully ameliorated DSS-induced colitis and that its effect may be associated with inhibiting inflammatory responses and maintaining intestinal integrity.

MiRNAs and inflammatory bowel disease: An interesting new story

Inflammatory bowel disease (IBD), as a chronic and recurrent inflammatory disorder, is caused by a dysregulated and aberrant immune response to exposed environmental factors in genetically susceptible individuals. Despite huge efforts in determining the molecular pathogenesis of IBD, an increasing worldwide incidence of IBD has been reported. MicroRNAs (miRNAs) are a set of noncoding RNA molecules that are about 22 nucleotides long, and these molecules are involved in the regulation of the gene expression. By clarifying the important role of miRNAs in a number of diseases, their role was also considered in IBD; numerous studies have been performed on this topic. In this review, we attempt to summarize a number of studies and discuss some of the recent developments in the roles of miRNAs in the pathophysiology, diagnosis, and treatment of IBD.

Heligmosmoides polygyrus fourth stages induce protection against DSS-induced colitis and change opioid expression in the intestine

Primary exposure of mice to the nematode Heligmosomoides polygyrus infection reduces inflammation in an experimental model of colitis. The aim of the present investigation was to evaluate whether the reduced inflammation provoked by H. polygyrus L4 larvae in BALB/c mice treated with dextran sulphate sodium is associated with changed expression of opioids in the small intestine and colon. Colitis was induced by 5% Dextran sulphate sodium (DSS) oral administration for 3 days before oral infection with 200 infective larvae (L3) H. polygyrus until the end of the experiment, 6 days post-infection. Clinical disease symptoms were monitored daily. The expressions of proopiomelanocortin POMC1, MOR1 (Oprm1) - opioid receptor and β-endorphin were determined by RT-PCR, Western blot and immunoassay, respectively, in the colon and small intestine of mice. RT-PCR analysis of colon tissues showed up-regulation of the expression of POMC and MOR1 opioid-dependent genes in mice with DSS-induced colitis. H. polygyrus L4 larvae inhibited DSS-induced colitis symptoms that were correlated with increased IL-1β, TNF-α, IL-6, myeloperoxidase (MPO) concentration, macrophages infiltration and MOR1, POMC and β-endorphin increased expression in the small intestine and inhibition of those in the colon.

Eosinophils in infection and intestinal immunity

PURPOSE OF REVIEW

Inflammatory bowel diseases (IBDs, e.g., Crohn's disease and ulcerative colitis) are thought to be a consequence of an uncontrolled inflammatory response against luminal antigens, including commensal bacteria. The observed link between eosinophil levels and severity and remission rates in IBD has led to speculation that eosinophils may contribute to the antimicrobial inflammatory response in IBD.

RECENT FINDINGS

Eosinophils express the necessary cellular machinery (innate immune receptors, proinflammatory cytokines, antibacterial proteins, and DNA traps) to mount an efficient antibacterial response; however, the rapid decline in eosinophil numbers following acute systemic bacterial infection suggests a very limited role for eosinophils in bacterial responses.

SUMMARY

We describe the clinical evidence of eosinophil involvement in IBD, summarize the in-vitro and in-vivo evidence of eosinophil antibacterial activity and the biology of eosinophils focusing on eosinophil-mediated bactericidal mechanisms and the involvement of eosinophil-derived granule proteins in this response, and conceptualize the contribution of eosinophils to a response against commensal bacteria in IBD.

Significance of heparanase in cancer and inflammation

Heparan sulfate proteoglycans (HSPGs) are primary components at the interface between virtually every eukaryotic cell and its extracellular matrix. HSPGs not only provide a storage depot for heparin-binding molecules in the cell microenvironment, but also decisively regulate their accessibility, function and mode of action. As such, they are intimately involved in modulating cell invasion and signaling loops that are critical for tumor growth, inflammation and kidney function. In a series of studies performed since the cloning of the human heparanase gene, we and others have demonstrated that heparanase, the sole heparan sulfate degrading endoglycosidase, is causally involved in cancer progression, inflammation and diabetic nephropathy and hence is a valid target for drug development. Heparanase is causally involved in inflammation and accelerates colon tumorigenesis associated with inflammatory bowel disease. Notably, heparanase stimulates macrophage activation, while macrophages induce production and activation of latent heparanase contributed by the colon epithelium, together generating a vicious cycle that powers colitis and the associated tumorigenesis. Heparanase also plays a decisive role in the pathogenesis of diabetic nephropathy, degrading heparan sulfate in the glomerular basement membrane and ultimately leading to proteinuria and kidney dysfunction. Notably, clinically relevant doses of ionizing radiation (IR) upregulate heparanase expression and thereby augment the metastatic potential of pancreatic carcinoma. Thus, combining radiotherapy with heparanase inhibition is an effective strategy to prevent tumor resistance and dissemination in IR-treated pancreatic cancer patients. Also, accumulating evidence indicate that peptides derived from human heparanase elicit a potent anti-tumor immune response, suggesting that heparanase represents a promising target antigen for immunotherapeutic approaches against a broad variety of tumours. Oligosaccharide-based compounds that inhibit heparanase enzymatic activity were developed, aiming primarily at halting tumor growth, metastasis and angiogenesis. Some of these compounds are being evaluated in clinical trials, targeting both the tumor and tumor microenvironment.

Heparanase enzyme in chronic inflammatory bowel disease and colon cancer

Heparanase is the sole mammalian endoglycosidase that cleaves heparan sulfate, the key polysaccharide of the extracellular matrix and basement membranes. Enzymatic cleavage of heparan sulfate profoundly affects a variety of physiological and pathological processes, including morphogenesis, neovascularization, inflammation, and tumorigenesis. Critical involvement of heparanase in colorectal tumor progression and metastatic spread is widely documented; however, until recently a role for heparanase in the initiation of colon carcinoma remained underappreciated. Interestingly, the emerging data that link heparanase to chronic inflammatory bowel conditions, also suggest contribution of the enzyme to colonic tumor initiation, at least in the setting of colitis-associated cancer. Highly coordinated interplay between intestinal heparanase and immune cells (i.e., macrophages) preserves chronic inflammatory conditions and creates a tumor-promoting microenvironment. Here we review the action of heparanase in colon tumorigenesis and discuss recent findings, pointing to a role for heparanase in sustaining immune cell-epithelial crosstalk that underlies intestinal inflammation and the associated cancer.

Inhibition of Pim-1 kinase ameliorates dextran sodium sulfate-induced colitis in mice

BACKGROUND

Pim-1 kinase is involved in the control of cell growth, differentiation and apoptosis. Recent evidence suggests that Pim kinases play a role in immune regulation and inflammation. However, the role of Pim-1 kinase in inflammatory bowel diseases (IBD) remains unclear.

AIMS

The aims of this study were to explore the role of Pim-1 kinase in the pathology of IBD and to assess whether inhibiting Pim-1 kinase may be of therapeutic benefit as a treatment regimen for IBD.

METHODS

Colitic mouse model was established by the induction of dextran sodium sulfate. The expression of Pim-1 in the colonic samples of control and colitic mice was examined. Furthermore, the mice were treated with Pim-1inhibitor (PIM-Inh), then the body weight and colon inflammation were evaluated, and the production of cytokines including IFN-γ, IL-4, TGF-β and IL-17 in colon tissues was determined by ELISA. The expression of T cell master transcription factors T-bet, ROR-γt, GATA-3 and Foxp3 and Nuclear factor κB (NF-κB) and inducible nitric oxide synthase in colon tissues was detected by real-time PCR and western blot. Finally, the effect of LPS on Pim-1 expression and the effects of PIM-Inh on LPS-induced upregualtion of p65 and TNF-α in RAW264.7 cells were examined by real-time PCR and western blot.

RESULTS

Pim-1 expression was correlated with the degree of mucosal inflammation in vivo, and it was significantly induced by LPS in vitro. PIM-Inh had protective effects on acute colitis in vivo. Mechanistically, PIM-Inh reduced the proinflammatory immune response through the inhibition of the overactivation of macrophages and the down-regulation of excessive Th1- and Th17-type immune responses. Furthermore, PIM-Inh could skew T cell differentiation towards a Treg phenotype.

CONCLUSIONS

Pim-1 kinase is involved in mucosal injury/inflammation and Pim-1 kinase inhibitor may provide a novel therapeutic approach for IBD.

CSF-1 receptor signalling from endosomes mediates the sustained activation of Erk1/2 and Akt in macrophages

Colony stimulating factor-1 (CSF-1) mediates its pleiotropic effects on macrophages through the CSF-1 receptor (CSF-1R), a receptor tyrosine kinase. Current models of CSF-1 signalling imply that the CSF-1R activates signalling pathways exclusively at the plasma membrane and the subsequent internalisation of the CSF-1R simply facilitates its lysosomal degradation in order to prevent on-going signalling. Here, we sought to establish if the CSF-1R may in fact continue to signal following its internalisation. Erk1/2, Akt and Stat3 activation were abrogated when the internalisation of the CSF-1R was impaired, with the effects on Stat3 distinct from those for Erk1/2 and Akt. Pharmacologic inhibition of the CSF-1R following its internalisation resulted in less sustained Erk1/2 and Akt activity, whereas Stat3 activity was unaffected. Significantly, the suppressive effects of the CSF-1R inhibitor on the up-regulation of gene expression by CSF-1 (e.g. cyclin D1 and Bcl-xL gene expression) were comparable irrespective of whether the inhibitor was added prior to CSF-1 stimulation or following the internalisation of the CSF-1R. Similarly, pharmacologic inhibition of Erk1/2 (or Akt) activity either prior to CSF-1 stimulation or subsequent to CSF-1R internalisation had comparable effects on the regulation of gene expression by CSF-1. Together, our data argue that key signalling responses to CSF-1 depend on the ability of the CSF-1R to signal from endosomes following its internalisation, thus adding an important spatiotemporal aspect to CSF-1R signalling.

Epigallocatechin-3-gallate Inhibits LPS-Induced NF-κB and MAPK Signaling Pathways in Bone Marrow-Derived Macrophages

Background/Aims

Epigallocatechin-3-gallate (EGCG), the primary catechin in green tea, has anti-inflammatory and anti-oxidative properties. The aim of the current study was to characterize the impact of EGCG on lipopolysaccharide (LPS)-induced innate signaling in bone marrow-derived macrophages (BMMs) isolated from ICR mice.

Methods

The effect of EGCG on LPS-induced pro-inflammatory gene expression and nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling was examined using reverse transcription-polymerase chain reaction, Western blotting, immunofluorescence, and the electrophoretic mobility shift assay.

Results

EGCG inhibited accumulation of LPS-induced IL-12p40, IL-6, MCP-1, ICAM-1, and VCAM-1 mRNA in BMMs. EGCG blocked LPS-induced IκBα degradation and RelA nuclear translocation. EGCG blocked the DNA-binding activity of NF-κB. LPS-induced phosphorylation of ERK1/2, JNK, and p38 was inhibited by EGCG. U0126 (an inhibitor of MEK-1/2) suppressed the LPS-induced IL-12p40, IL-6, MCP-1, ICAM-1, and VCAM-1 mRNA accumulation in BMMs.

Conclusions

These results indicate that EGCG may prevent LPS-induced pro-inflammatory gene expression through blocking NF-κB and MAPK signaling pathways in BMMs.

Efficient intracellular drug-targeting of macrophages using stealth liposomes directed to the hemoglobin scavenger receptor CD163

The hemoglobin scavenger receptor CD163 is exclusively expressed in the monocytic lineage and preferentially in tissue resident macrophages of the M2 phenotype and in macrophages in sites of inflammation and tumor growth. In the present study we have designed liposomes specifically targeting CD163 by hydrophobic linkage of CD163-binding monoclonal antibodies to polyethylene glycol-coated liposomes ('stealth liposomes'). Targeting to the endocytic CD163 protein greatly increased the uptake of liposomes in CD163 transfected cells and macrophages as visualized by confocal microscopy and flow cytometry of cells exposed to CD163 targeting liposomes loaded with calcein. Strong cytotoxic effects were seen in CD163-expressing human monocytes by using the chemotherapeutic agent doxorubicin as cargo of the liposomes. In conclusion, the use of stealth liposomes modified to recognize CD163 is a potential way to target drugs to macrophages that support inflammatory and malignant processes.

Gadofluorine M-enhanced magnetic resonance imaging of inflammatory bowel disease: quantitative analysis and histologic correlation in a rat model

OBJECTIVES

: To determine the colonic mural enhancement in a rat model of inflammatory bowel disease (IBD) using gadofluorine M- and diethylenetriamine pentaacetic acid (Gd-DTPA)-enhanced magnetic resonance (MR) imaging, and to correlate the degree of enhancement with the histopathologic severity of the disease.

MATERIALS AND METHODS

: This study was approved by our hospital's institutional animal care and use committee. A total of 44 rats with 2 grades (mild, n = 17; and severe, n = 27) of dinitrobenzene sulfonic acid (DNBS)-induced IBD and 13 rats without IBD, were examined using a 2.4-T, small animal MR scanner. T2- and T1-weighted MR images were acquired, and sequential T1-weighted MR imaging was then performed immediately and again 15, 45, 60, and 90 minutes, and 24 hours after intravenous -injection of either gadofluorine M- or Gd-DTPA (0.1 mmol Gd/kg body weight). The signal-to-noise ratios and enhancement ratios (ER) of the colon wall were measured. For paired and group comparisons of the histopathology and MR imaging data, the Wilcoxon- and the Mann-Whitney U tests were used, and the multifactorial analysis of variance test was used to compare the time courses of the ERs.

RESULTS

: Gadofluorine M injection resulted in significant differences in the ER of noninflamed, mildly inflamed, and severely inflamed colon wall at any time up to 24 hours after contrast injection (ER at 24 hours 2.0 ± 1.2; 10.1 ± 4.3; and 49.7 ± 10.8, respectively; P < 0.01). After Gd-DTPA injection, significant differences were observed in the ER of inflamed and noninflamed bowel at 15, 45, and 60 minutes (P < 0.01); however, no significant differences in mildly and severely inflamed bowel were observed at any time. In contrast to Gadofluorine M, there was no prolonged contrast enhancement in the inflamed colon wall after intravenous injection of Gd-DTPA (ER at 24 hours 1.6 ± 1.3; 3.4 ± 2.7; and 3.3 ± 1.6, respectively; n.s.).

CONCLUSIONS

: Gadofluorine M-enhanced MR imaging shows a higher correlation of the wall enhancement and histopathology grading in an IBD rat model than does Gd-DTPA-enhanced imaging.

Regulation of inflammation in cancer by eicosanoids

Inflammation in the tumor microenvironment is now recognized as one of the hallmarks of cancer. Endogenously produced lipid autacoids, locally acting small molecule lipid mediators, play a central role in inflammation and tissue homeostasis, and have recently been implicated in cancer. A well-studied group of autacoid mediators that are the products of arachidonic acid metabolism include: the prostaglandins, leukotrienes, lipoxins and cytochrome P450 (CYP) derived bioactive products. These lipid mediators are collectively referred to as eicosanoids and are generated by distinct enzymatic systems initiated by cyclooxygenases (COX 1 and 2), lipoxygenases (5-LOX, 12-LOX, 15-LOXa, 15-LOXb), and cytochrome P450s, respectively. These pathways are the target of approved drugs for the treatment of inflammation, pain, asthma, allergies, and cardiovascular disorders. Beyond their potent anti-inflammatory and anti-cancer effects, non-steroidal anti-inflammatory drugs (NSAIDs) and COX-2 specific inhibitors have been evaluated in both preclinical tumor models and clinical trials. Eicosanoid biosynthesis and actions can also be directly influenced by nutrients in the diet, as evidenced by the emerging role of omega-3 fatty acids in cancer prevention and treatment. Most research dedicated to using eicosanoids to inhibit tumor-associated inflammation has focused on the COX and LOX pathways. Novel experimental approaches that demonstrate the anti-tumor effects of inhibiting cancer-associated inflammation currently include: eicosanoid receptor antagonism, overexpression of eicosanoid metabolizing enzymes, and the use of endogenous anti-inflammatory lipid mediators. Here we review the actions of eicosanoids on inflammation in the context of tumorigenesis. Eicosanoids may represent a missing link between inflammation and cancer and thus could serve as therapeutic target(s) for inhibiting tumor growth.

The role of p38 mitogen-activated protein kinase in the pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) includes ulcerative colitis and Crohn's disease which is characterized by the recurrent intestinal inflammation and overactive immune responses. The signaling pathways of p38 mitogen-activated protein kinase (MAPK) play an important role in bowel inflammation. The inhibition of p38 MAPK can effectively suppress the expression of inflammatory mediators. However, due to the obvious preclinical and clinical side effects, p38 inhibitors are unacceptable in safety profiles and cannot be applied in the treatment of IBD. MAPK-activated protein kinase 2 (MK2), as the direct substrate of p38α and p38β, is a multifunctional signaling protein in the progression of inflammation and several lines of evidence demonstrate that the inhibition of MK2 may produce the same beneficial effect as the inhibition of p38 MAPK. Hence, MK2 is likely to be a potential drug target for the treatment of IBD.

Methyl-1-hydroxy-2-naphthoate, a novel naphthol derivative, inhibits lipopolysaccharide-induced inflammatory response in macrophages via suppression of NF-κB, JNK and p38 MAPK pathways

OBJECTIVE AND DESIGN

The anti-inflammatory effect of methyl-1-hydroxy-2-naphthoate (MHNA), a novel naphthol derivative, was evaluated in the lipopolysaccharide (LPS)-induced inflammatory response in murine macrophages.

MATERIALS AND METHODS

The release of nitric oxide (NO), interleukin-1beta (IL-1β) and interleukin-6 (IL-6) were detected by the Griess reagent and ELISA methods. The protein expressions of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) were examined by Western blotting. The mRNA expressions of IL-1β, IL-6, iNOS and COX-2 were determined by real-time PCR. Activation of mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB) pathways were detected by Western blotting, reporter gene assay and electrophoretic mobility shift assay.

RESULTS

MHNA significantly inhibited the release of NO, IL-1β and IL-6 as well as the protein expression of iNOS and COX-2 in LPS-stimulated macrophages. It also inhibited the mRNA expression of iNOS, COX-2, IL-1β and IL-6. Further studies indicated that MHNA inhibited LPS-induced increases in NF-κB DNA-binding activity and NF-κB transcriptional activity as well as IκB-α degradation and NF-κB translocation in a dose-dependent manner. Meanwhile, the activation of p38 MAPK and c-Jun N-terminal kinases (JNK) induced by LPS were decreased by MHNA.

CONCLUSIONS

MHNA inhibits the LPS-induced inflammatory response in murine macrophages via suppression of NF-κB and MAPKs signaling pathways activation.

Kiwifruit extracts inhibit cytokine production by lipopolysaccharide-activated macrophages, and intestinal epithelial cells isolated from IL10 gene deficient mice

Inflammatory bowel disease (IBD) is a chronic, inflammatory disorder of the gastrointestinal tract involving an inappropriate immune response to commensal microorganisms in a genetically susceptible host. This study examined the effects of aqueous and ethyl acetate extracts of gold kiwifruit (Actinidia chinensis) or green kiwifruit (Actinidia deliciosa) using in vitro models of IBD. These models comprised primary macrophages and intestinal epithelial cells isolated from C57BL/5J and interleukin-10 gene deficient (Il10(-/-)) mice and RAW 264.7, a murine macrophage-like cell line. All four kiwifruit extracts reduced the activation of these models after lipopolysaccharide stimulation, decreasing nitric oxide and cytokine secretion by both Il10(-/-) and wild-type cells. The ethyl acetate extracts exhibited the highest anti-inflammatory activity, with almost complete suppression of lipopolysaccharide-stimulated macrophage activation. These results suggest that kiwifruit extracts have significant anti-inflammatory activity relevant to IBD. We suggest that the Il10(-/-) mouse is a suitable model for further study of these compounds.

Heparanase powers a chronic inflammatory circuit that promotes colitis-associated tumorigenesis in mice

Ulcerative colitis (UC) is a chronic inflammatory bowel disease that is closely associated with colon cancer. Expression of the enzyme heparanase is clearly linked to colon carcinoma progression, but its role in UC is unknown. Here we demonstrate for what we believe to be the first time the importance of heparanase in sustaining the immune-epithelial crosstalk underlying colitis-associated tumorigenesis. Using histological specimens from UC patients and a mouse model of dextran sodium sulfate-induced colitis, we found that heparanase was constantly overexpressed and activated throughout the disease. We demonstrate, using heparanase-overexpressing transgenic mice, that heparanase overexpression markedly increased the incidence and severity of colitis-associated colonic tumors. We found that highly coordinated interactions between the epithelial compartment (contributing heparanase) and mucosal macrophages preserved chronic inflammatory conditions and created a tumor-promoting microenvironment characterized by enhanced NF-κB signaling and induction of STAT3. Our results indicate that heparanase generates a vicious cycle that powers colitis and the associated tumorigenesis: heparanase, acting synergistically with the intestinal flora, stimulates macrophage activation, while macrophages induce production (via TNF-α-dependent mechanisms) and activation (via secretion of cathepsin L) of heparanase contributed by the colon epithelium. Thus, disruption of the heparanase-driven chronic inflammatory circuit is highly relevant to the design of therapeutic interventions in colitis and the associated cancer.

Clinical and endoscopic features of responders and non-responders to adsorptive leucocytapheresis: a report based on 120 patients with active ulcerative colitis

BACKGROUND AND OBJECTIVE

Elevated/activated myeloid leucocytes, like the CD14(+)CD16(+) monocytes are sources of TNF-α, and therefore, selective depletion of these cells by granulocyte/monocyte (GM) adsorption (GMA) should promote remission or enhance drug efficacy. However, studies in ulcerative colitis (UC) reported contrasting efficacy, from an 85% to statistically insignificant level. We investigated patients' demography in responders and non-responders.

METHODS

In 120 UC patients, 61 steroid naive and 59 steroid dependent, we looked for entry clinical or endoscopic features to identify responders (or non-responders) to GMA. Patients received up to an 11 Adacolumn GMA sessions over 12 weeks. Patients were clinically and endoscopically evaluated, allowing each patient to serve as her/his own control. Immunohistochemistry on colonic biopsies was to reveal the impact of GMA on leucocyte infiltration of the mucosa.

RESULTS

Entry average clinical activity index (CAI) was 12.6, 10-16. An 80 of 120 patients responded (CAI≤4); 45 steroid naïve (73.8%) and 35 steroid dependent (59.3%). Over 900 biopsies were processed. Infiltrating leucocytes were overwhelmingly polymorphonuclear and macrophages around and within crypt abscesses. There was a marked reduction of infiltrating leucocytes in responders. Most non-responders had extensive colonic lesions with virtually no mucosal tissue left at the lesions.

CONCLUSIONS

Steroid naïve patients with short duration of UC were the best responders, while patients with deep colonic lesions and extensive loss of the mucosal tissue were non-responders.

Impaired olfactory function in mice with allergic rhinitis

OBJECTIVE

It has been reported that olfactory function is impaired in patients with allergic rhinitis. However, the mechanism of olfactory dysfunction in allergic rhinitis remains poorly understood. Because of difficulties in obtaining and analyzing human olfactory mucosa due to both technical and ethical issues, an animal model needs to be established to clarify the mechanism of olfactory dysfunction in allergic rhinitis. The purpose of this study was to study olfactory function and changes in olfactory mucosa using allergic rhinitis mice.

METHODS

A model of allergic rhinitis mice with olfactory dysfunction was developed by sensitizing with ovalbumin (OVA), and intranasally challenging with the same allergen. Olfactory function of mice with or without allergic rhinitis was assessed by odor detection ability test with cycloheximide and local field potential (LFP) with 1-octanal. We also evaluated histological changes in the olfactory mucosa of allergic rhinitis mice by both light and electron microscopy.

RESULTS

Both of odor detection ability test and LFP showed that olfactory function was impaired in mice with allergic rhinitis, but not in mice without allergic rhinitis. Histopathological findings showed prominent infiltration of eosinophils, plasma cells, neutrophils, mast cells, and macrophages in lamina propria of olfactory mucosa of mice with allergic rhinitis, although infiltration of these cells was not seen in control mice. Allergic rhinitis also increased the number and size of glands in olfactory mucosa, suggesting an elevated amount of mucin in olfactory mucosa.

CONCLUSION

This study showed for the first time that mice with allergic rhinitis have impaired olfactory function, increased size and number of olfactory glands, and infiltration of eosinophils, neutrophils, mast cells, plasma cells, and macrophages in the olfactory mucosa. This suggests that allergic reactions are seen in olfactory mucosa of mice with allergic rhinitis, and that greater olfactory gland activity is associated with olfactory dysfunction. Also, this mouse model could provide an expedient system for analyzing mechanisms of olfactory dysfunction.

Dichroa febrifuga Lour. inhibits the production of IL-1beta and IL-6 through blocking NF-kappaB, MAPK and Akt activation in macrophages

AIM OF THE STUDY

The roots of Dichroa febrifuga Lour. have been used as a traditional antimalarial drug and also used in the treatment of productive cough and unstable fever caused by infection in China and Korea. In this study, we evaluated the anti-inflammatory effect and underlying molecular mechanism of aqueous extract of Dichroa febrifuga (AEDF) in C57BL/6 mouse peritoneal macrophages.

MATERIALS AND METHODS

The effect of AEDF on proinflammatory cytokine (IL-1beta and IL-6) production was analyzed by ELISA and real-time RT-PCR. The effects of AEDF on NF-kappaB/IkappaB-alpha/IKK were measured by reporter assay (in RAW 264.7 cells), EMSA, Western blotting and kinase assay. The effects of AEDF on Akt and MAPKs activity were assayed by Western blotting.

RESULTS

AEDF inhibited the production of IL-1beta and IL-6, NF-kappaB activation, IkappaB-alpha degradation, and IKK, Akt, ERK1/2 and JNK activities in LPS-stimulated mouse peritoneal macrophages.

CONCLUSIONS

These results suggest that AEDF inhibits proinflammatory cytokine (IL-1beta and IL-6) production in LPS-stimulated mouse peritoneal macrophages, and that these effects are mediated by the inhibition of the activity of IKK/IkappaB/NF-kappaB and the phosphorylation of Akt, ERK1/2, and JNK. Our results provide a molecular basis for understanding the inhibitory effects of Dichroa febrifuga roots on endotoxin-mediated inflammation.

In patients with ulcerative colitis, adsorptive depletion of granulocytes and monocytes impacts mucosal level of neutrophils and clinically is most effective in steroid naïve patients

BACKGROUND

The aetiology of ulcerative colitis is inadequately understood, and drug therapy has been empirical rather than based on sound understanding of disease aetiology. This has been a major factor for refractoriness and adverse drug effects as additional complications. However, ulcerative colitis by its very nature is exacerbated and perpetuated by inflammatory cytokines, which are released by peripheral granulocytes and monocytes as well. Additionally, active ulcerative colitis is often associated with elevated peripheral granulocytes and monocytes with activation behaviour and are found in vast numbers within the colonic mucosa. Hence, from the clinicopathologic viewpoint, granulocytes and monocytes are appropriate targets for therapy in ulcerative colitis. Based on this thinking, an Adacolumn has been developed for depleting excess granulocytes and monocytes by adsorption.

METHODS

By colonoscopy, biopsy and histology, we investigated the impact of granulocyte and monocyte adsorption (GMA) on the mucosal level of granulocytes and monocytes in patients with active ulcerative colitis. Forty-five patients (26 steroid naïve and 19 steroid-dependent), mean age 44.7 yr, were included. Twenty patients had total colitis and 25 had left-sided colitis. Each patient was given up to 11 GMA sessions over 12 weeks. No patient received additional medications within 4 weeks (steroid) to 8 weeks (other immunosuppressants) prior to entry or during the GMA course. Colonoscopy together with biopsy was done at entry and within 2 weeks after the last GMA session.

RESULTS

At entry, the mean clinical activity index was 12.6; range 10-16. A total of 400 colonic biopsies were examined, which revealed massive infiltration of the colonic mucosa by granulocytes, and GMA was associated with striking reduction of granulocytes in the mucosa. At week 12, 33 of 45 patients (73.3%, P<0.01) had achieved clinical remission (the mean clinical activity index <or= 4). Colonoscopy revealed that most non-responders had deep colonic ulcers and extensive loss of the mucosal tissue. The response rate in steroid naïve subgroup was 22 of 26 patients (84.6%, P<0.005) and in steroid-dependent was 11 of 19 (57.9%, P<0.05 and P=0.02154 for steroid naïve vs. steroid-dependent). Patients who achieved remission could continue with their salicylates. On average, remission was sustained for 7.8 months in all 33 responders.

CONCLUSIONS

This is the first report showing a striking difference in clinical response to GMA between steroid naïve and steroid-dependent patients. Further, patients with deep colonic ulcers together with extensive loss of the mucosal tissue are not like to respond to GMA.

Intensive granulocyte and monocyte adsorption versus intravenous prednisolone in patients with severe ulcerative colitis: an unblinded randomised multi-centre controlled study

BACKGROUND AND AIM

Several uncontrolled studies have reported on the efficacy of adsorptive depletion of peripheral blood granulocytes and monocytes/macrophages (GM) in patients with moderate or severe ulcerative colitis. This study was to compare the efficacy and safety of intensive GMA with intensive intravenous prednisolone in patients with severe ulcerative colitis.

METHODS

Seventy patients with clinical activity index 10-23 were randomly assigned to intensive GMA with the Adacolumn, at 2 sessions/week in the first 3 weeks and then 1 session/week for up to 11 sessions (n = 35) or intravenous prednisolone, 40-60 mg/day for 5-10 days (n = 35). No patient received immunomodulators within 8 weeks prior to entry. Clinical response based on intention to treat was assessed at weeks 2, 6 and 12.

RESULTS

Four patients in the prednisolone group and two patients in the GMA group discontinued in week 1. At weeks 2, 6 and 12, the remission (clinical activity index < or = 4) rates (%) in the GMA group were 17.1, 54.4, 74.3, respectively. The corresponding values in the prednisolone group were 25.7, 51.4 and 48.6. Further, at week 12, 27 patients (77%) in the GMA group and 5 patients (14%) in the prednisolone group were steroid free (P = 0.0076). In the GMA group, flushing and light-headedness were observed in 5 patients versus typical steroid side effects in 29 patients of the prednisolone group.

CONCLUSIONS

In this clinical response to GMA was comparable or better than prednisolone. Further, the response to GMA was slower than to intravenous prednisolone, but was more sustainable than the latter.

A prominent role for mucosal cystine/cysteine metabolism in intestinal immunoregulation

BACKGROUND & AIMS

T-cell receptor reactivity of intestinal lamina propria T cells (LP-T) critically depends on the capacity of local accessory cells to secrete cysteine. For T cells, cysteine is the limiting precursor for glutathione synthesis, a prerequisite for antigen-dependent proliferation. We aimed to determine the role of the redoxactive microenvironment for hyporeactivity of LP-T in normal human gut vs hyperreactivity of LP-T in inflammatory bowel disease.

METHODS

Parameters relevant to cysteine production, determined as acid-soluble thiol, by intestinal lamina propria macrophages (LP-MO) vs peripheral blood monocytes were investigated (L-[(35)S]cystine uptake via system x(c)(-), messenger RNA, and protein expression of the cystine transporter subunit xCT). Glutathione levels in LP-T and peripheral blood T cells were analyzed both spectrophotometrically and by immunofluorescent staining in situ and in vitro.

RESULTS

LP-MO from normal gut, unlike peripheral blood monocytes, are unable to take up cystine, which is due to a deficient expression of the transporter xCT in situ and in vitro. As a consequence, LP-MO do not secrete cysteine. The glutathione content in LP-T from normal gut is <50% of that in autologous peripheral blood T cells. In contrast, in inflammatory bowel disease, CD14(+)CD68(+) LP-MO express xCT and secrete substantial amounts of cysteine upon stimulation, which results in high glutathione levels and full T-cell receptor reactivity in LP-T.

CONCLUSIONS

The antioxidative microenvironment of LP-T in inflammatory bowel disease and the prooxidative microenvironment in normal gut explain the differential T-cell receptor reactivities.

Factors affecting clinical and endoscopic efficacies of selective leucocytapheresis for ulcerative colitis

BACKGROUND

Granulocyte, monocyte/macrophage adsorptive apheresis is a novel treatment for active ulcerative colitis. However, as yet no study has reported on a subset of patients who might respond well to granulocyte, monocyte/macrophage adsorptive apheresis therapy.

AIM

To identify factors affecting clinical and endoscopic efficacies of granulocyte, monocyte/macrophage in patients with ulcerative colitis.

METHODS

Fifty consecutive patients with active ulcerative colitis initially received five granulocyte, monocyte/macrophage adsorptive apheresis sessions with the Adacolumn over five consecutive weeks. Patients who improved without achieving remission received five additional granulocyte, monocyte/macrophage adsorptive apheresis sessions.

RESULTS

One week after the last granulocyte, monocyte/macrophage adsorptive apheresis session, 26 (52%) and 17 patients (34%) achieved clinical and endoscopic remission, respectively. In the multivariate analysis, the dose of prednisolone administered at entry and the cumulative dose of prednisolone administered before entry were independent significant factors for both clinical and endoscopic remission, negatively impacted the efficacy of granulocyte, monocyte/macrophage adsorptive apheresis. Age, gender, duration of ulcerative colitis, number of prior relapses, duration of current exacerbation, extent and severity of ulcerative colitis, extra-intestinal manifestations, entry haematology values and C-reactive protein did not affect the outcome.

CONCLUSIONS

Based on the outcomes of this study, it appears that steroid-naïve patients and patients on low dose steroid and short duration of exposure respond to granulocyte, monocyte/macrophage adsorptive apheresis. Further studies in larger cohorts of patients should strengthen our findings.

Adacolumn selective leukocyte adsorption apheresis in patients with active ulcerative colitis: clinical efficacy, effects on plasma IL-8, and expression of Toll-like receptor 2 on granulocytes

Adacolumn selective granulocyte and monocyte apheresis (GMA) depletes activated leukocytes in patients with ulcerative colitis (UC). However, this per se cannot fully explain the efficacy of GMA. We have investigated the effects of GMA on the expression of toll-like receptors (TLRs) and plasma interleukin-8 (IL-8). Twenty-two patients with clinical activity index (CAI) of 5-17, 15 with total colitis and 7 with left-sided colitis, were included. Each patient could receive up to 10 GMA sessions, at 1 or 2 sessions per week. GMA was added to the patients' ongoing medication following a relapse or worsening UC, but no additional medication was given. Further, at entry and pre-GMA, blood samples were taken for full blood cell count, expression of TLRs on leukocytes, and plasma IL-8. Seventy-five percent of patients achieved remission after the 10th session (CAI, < or =4; P < 0.005) and there was a marked fall in C-reactive protein (P < 0.01), plasma IL-8 (P < 0.001), and granulocytes (P < 0.05) but an increase in lymphocytes (P < 0.05). The expression of TLR2 on granulocytes was down-modulated (P < 0.05) together with suppression of inflammatory cytokines produced by peripheral blood leukocytes. In conclusion, GMA appears to be an effective adjunct therapy to induce remission in the majority of patients, who are then spared from excess drug therapy. The procedure is associated with sustained immunomodulation. Control studies should strengthen these findings.

Immune dysfunction in inflammatory bowel disease

Ulcerative colitis (UC) and Crohn's disease (CD) are idiopathic inflammatory bowel diseases (IBDs) that are characterized by chronic periods of exacerbation and remission. Research into the immunopathogenesis of IBD adds support to the theory that the disease results from a dysfunctional regulation of the immune system that leads to the polarization of intestinal immune cells toward a Th1 (T helper) response. The immunologic factors that mediate alterations in intestinal homeostasis and the development of intestinal mucosal inflammation have been at the forefront of IBD research. Cytokines, which are important regulators of leukocyte trafficking and apoptotic cell death, have emerged as essential immune molecules in the pathogenesis of IBD. In this study, recent advances in the understanding of the dynamism of cytokines and the consequences for mucosal immunity and inflammation in IBD are discussed. Furthermore, this study highlights the potential use of cytokines, anti-cytokine antibodies, and cytokine-related biologic therapies as novel targets for the treatment of IBD.

Clinical evaluation of granulocyte/monocyte apheresis therapy for active ulcerative colitis

BACKGROUND

Recent evidence suggests that peripheral blood granulocytes and monocytes/macrophages have a major role in the exacerbation of ulcerative colitis.

AIMS

Our objective was to investigate if selective granulocyte and monocyte adsorptive apheresis with Adacolumn promotes remission of active ulcerative colitis and spares corticosteroid.

SUBJECTS

Sixty patients with active ulcerative colitis were studied, of whom 39 had relapsing-remitting ulcerative colitis, 15 had chronic continuous and 6 had their first episode of ulcerative colitis.

METHODS

Granulocytapheresis was done with an Adacolumn filled with cellulose acetate beads as apheresis carriers that adsorb FcgammaR and complement receptors bearing leucocytes (granulocytes, monocytes and a small fraction of lymphocytes). Patients received up to 10 Adacolumn sessions over 12 weeks, one session was 60-90 min at 30 mL/min. No additional medication was given. Efficacy was assessed with Seo's activity index (AI) [Seo M, Okada M, Yao T. An index of disease activity in patients with ulcerative colitis. Am J Gastroenterol 1992;87:971-6]. The mean AL was 197.5 and range 154.4-277.7. AI < 150 was considered significant improvement and AI < 100 was considered clinical remission.

RESULTS

Of 60 patients, 50 (83.3 %) improved, 14 achieved remission, granulocytapheresis was most effective in steroid-dependent patients. At entry, the mean dose of prednisolone was 15.3 mg/day per patient and was reduced to 3.6 mg/day after 10 sessions. Granulocytapheresis was well tolerated and no serious side-effects were observed.

CONCLUSION

Based on our experience in patients with diverse ulcerative colitis disease expression and long-term exposure to conventional drug therapy, we believe that granulocytapheresis is an effective adjunct to conventional medication for promoting remission and sparing steroids in patients with active ulcerative colitis.

Rho kinase blockade prevents inflammation via nuclear factor kappa B inhibition: evidence in Crohn's disease and experimental colitis

BACKGROUND & AIMS

Rho proteins are involved in the regulation of several cellular functions. Data from in vitro studies suggest that RhoA could be involved in the inflammatory response. We investigated the role of RhoA and its downstream effector Rho kinase in intestinal inflammation.

METHODS

Activation of RhoA was assessed by pull-down assays. A specific inhibitor of Rho kinase, Y-27632, was used to examine the role of Rho kinase in inflammatory response in vivo and in vitro by molecular biology and by immunological and biochemical approaches.

RESULTS

Increased activation of RhoA was found in inflamed intestinal mucosa of patients with Crohn's disease and of rats with 2,4,6-trinitrobenzene sulfonic acid-induced colitis. Oral administration of Y-27632 in rats significantly reduced the colonic inflammation. In vitro, activation of RhoA alone was sufficient to induce tumor necrosis factor production. Y-27632 inhibited production of tumor necrosis factor-alpha and interleukin-1 beta by lamina propria and peripheral blood mononuclear cells. Rho kinase inhibition prevented nuclear factor kappa B activation and I-kappa B phosphorylation and degradation. We showed that Rho kinase associates with and activates I-kappa B kinase alpha and that Y-27632 prevents I-kappa B kinase activation.

CONCLUSIONS

Our study provides the first evidence that Rho kinase activates I-kappa B kinase and, thus, nuclear factor kappa B, suggesting a key role of Rho kinase in inflammatory responses and intestinal inflammation. Specific inhibition of Rho kinase may be a promising approach for the treatment of patients with Crohn's disease.

Maternal milk reduces severity of necrotizing enterocolitis and increases intestinal IL-10 in a neonatal rat model

Necrotizing enterocolitis (NEC) is a devastating intestinal disease of premature infants. Maternal milk has been suggested to be partially protective against NEC; however, the mechanisms of this protection are not defined. The aim of this study was to examine the effect(s) of artificial feeding of rat milk (RM)-versus cow milk-based rat milk substitute (RMS) on the development of NEC in a neonatal rat model and elucidate the role of inflammatory cytokines in NEC pathogenesis. Newborn rats were artificially fed with either collected RM or RMS. Experimental NEC was induced by exposure to asphyxia and cold stress and evaluated by histologic scoring of damage in ileum. Intestinal cytokine mRNA expression was determined by real-time PCR. Cytokine histologic localization was performed by confocal microscopy. Similar to human NEC, artificial feeding of RM reduces the incidence and severity of NEC injury in neonatal rats. Freezing and thawing of collected RM did not eliminate the protective effect of maternal milk. Ileal IL-10 expression was significantly increased in the RM group compared with RMS. Increased IL-10 peptide production was detected in the RM group with signal localized predominantly in the cytoplasm of villus epithelial cells. These results suggest that the protective effect of maternal milk is associated with increased production of anti-inflammatory IL-10 in the site of injury. Better understanding of the mechanisms underlying these protective effects could be beneficial either in the prevention of NEC or in the development of future therapeutic strategies to cure NEC.

Leukocyte adsorptive apheresis for the treatment of active ulcerative colitis: a prospective, uncontrolled, pilot study

BACKGROUND AND AIMS

Active ulcerative colitis (UC) is characterized by infiltration of activated granulocytes and monocytes/macrophages (GM) within the large bowel mucosa. GM are major sources of inflammatory cytokines, and in UC they are elevated with increased survival time. We investigated the possibility that reducing the level of these cells might promote remission of active UC.

METHODS

Thirty-one patients with active corticosteroid refractory (refractory) UC, mean age of 42 years, duration of UC 6 years, clinical activity index (CAI) of 15, disease activity index (DAI) of 10, and 8 corticosteroid naive patients (naive), mean age of 36 years, duration of UC 2 years, CAI of 11, DAI of 8 were recruited. Each patient was treated with up to 11 cycles of granulocyte and monocyte adsorptive apheresis over 11 weeks by using a 335-mL capacity column filled with cellulose acetate beads that adsorb GM.

RESULTS

At week 12, 81% of refractory (CAI, 3; P < 0.001 and DAI, 4; P < 0.001) and 88% of naive (CAI, 1; P = 0.012 and DAI, 3; P = 0.011) patients achieved remission. Early relapse was not a feature, and at 12 months, 26 of 33 patients had maintained their remission. The treatment was well tolerated, and no severe side effects were observed.

CONCLUSIONS

The outcome of this study suggests that reduction of circulating granulocytes and monocytes results in alleviation of inflammation and promotes clinical remission in patients with severe active UC that has not responded to intensive corticosteroid treatment. These data suggest that formal controlled studies are warranted.

Serum interleukin-18 concentrations in patients with inflammatory bowel disease

Elevated expression of interleukin (IL)-18 mRNA and protein in intestinal mucosa, attributable to activated monocytes and macrophages in that site, has been reported in patients with inflammatory bowel disease (IBD). However, changes in serum IL-18 concentrations in patients with IBD have not been reported. We measured bioactive IL-18 in serum from patients with IBD, using an enzyme-linked immunosorbent assay (ELISA). Mean serum IL-18 concentrations in 5 patients with Crohn disease (CD) were 400 pg/mL, approximately 1.7 times higher than concentrations in 21 control subjects (p < 0.01). However, serum IL-18 was not increased in patients with ulcerative colitis (UC). These results suggest that like other T-helper type 1 (Th1) cytokines IL-18 may play a key pathogenetic role in Th1-mediated disorders, such as CD. Regulation and expression of IL-18 appears to differ between CD and UC, and serum IL-18 may be a useful clinical marker for CD.

The constitutive expression of galectin-3 is downregulated in the intestinal epithelia of Crohn's disease patients, and tumour necrosis factor alpha decreases the level of galectin-3-specific mRNA in HCT-8 cells

OBJECTIVE

Galectin-3, a lectin with specificity for beta galactoside, is expressed by a variety of cells, including intestinal epithelial cells. Among other functions, galectin-3 mediates cell adhesion and is involved in inflammatory processes. In this study, we assessed the expression of galectin-3 in intestinal epithelial cells from Crohn's disease patients (n = 10), ileum adjacent to resected colon carcinoma (n = 9), unspecific bowel inflammation (n = 1), diverticulosis (n = 1), ulcerative colitis (n = 3) and healthy jejunum used for interposition in larynx carcinoma (n = 1). The role of cytokines on galectin-3 expression was a further aim of our study.

METHODS

The galectin-3 distribution in intestinal epithelia was analysed by immunohistochemistry, immunoblotting, immunofluorescence and reverse transcriptase polymerase chain reaction (RT-PCR). Human intestinal epithelial cell line (HCT-8) and primary cultured intestinal epithelial cells were treated with cytokines, and the effects on galectin-3 expression were determined by RT-PCR.

RESULTS

Galectin-3 showed a homogeneous distribution in epithelia from control patients. In contrast, in epithelial cells from Crohn's disease lesions, galectin-3 staining was strongly spotted and heterogeneous. In inflamed and reorganized tissue, galectin-3 expression was markedly reduced, and was associated with disintegration of epithelia. Primary cultured epithelial cells as well as HCT-8 cells expressed galectin-3 protein and mRNA. Incubation of HCT-8 cells with tumour necrosis factor alpha (TNF-alpha), but not with other cytokines, substantially reduced galectin-3 expression as shown by semiquantitative RT-PCR.

CONCLUSIONS

Downregulation of galectin-3 in the intestinal epithelium of Crohn's disease patients may be a consequence of enhanced TNF-alpha production by inflammatory cells, thereby contributing to the pathophysiology of the disease.