Jianning Dong

Celastrol ameliorates experimental colitis in IL-10 deficient mice via the up-regulation of autophagy.

BACKGROUND Celastrol had been proved effective in the treatment for IBD, probably with the modulation of oxidative stress, inflammatory cytokines and intestinal homeostasis. This study was aimed to investigate whether celastrol could ameliorate the inflammation of IL-10 deficient mice, a murine model of Crohns disease (CD) with the induction of autophagy. MATERIAL AND METHODS The mice included were divided into four groups, ##WT group, IL-10(-/-) group, Cel group and Control group (celastrol+3-Methyladenine). Celastrol (2 mg/kg) treatment by gavage was administered to mice daily over one week. 3-Methyladenine (autophagy inhibitors) was administered at a dose of 30 mg/kg by intraperitoneal injection. The histological evaluation of the colon, tissue myeloperoxidase (MPO), and colon inflammation of mice in the four groups was evaluated and compared. Furthermore, the PI3K/Akt/mTOR pathway and the status of autophagy in intestine affected by celastrol were also assessed. RESULTS The one-week administration of celastrol ameliorated established colitis in IL-10 deficient mice, associated with a reduction of marked histological inflammation, a decreased colon MPO concentration and suppression of colonic proinflammatory cytokine. Furthermore, the decreased neutrophil infiltration in proximal colon and improvement of inflammation in the Cel group was much more obvious than that in the Control group. The Western blotting analysis of the PI3K/Akt/mTOR pathway and autophagy showed that celastrol treatment up-regulated the autophagy of colon tissue by suppressing the PI3K/Akt/mTOR signaling pathway. CONCLUSIONS Celastrol ameliorates experimental colitis in IL-10 deficient mice via the up-regulation of autophagy by suppressing the PI3K/Akt/mTOR signaling pathway.

Oral treatment with SEW2871, a sphingosine-1-phosphate type 1 receptor agonist, ameliorates experimental colitis in interleukin-10 gene deficient mice

SEW2871, a selective sphingosine‐1‐phosphate type 1 receptor (S1P1) agonist, has been shown to be effective in protecting kidneys against ischaemia–reperfusion injury by reducing CD4+ T cell infiltration in mice. However, the effects of SEW2871 on colitis remain unclear. The aim of this study was to investigate the effects of SEW2871 on established colitis in interleukin (IL)‐10 gene‐deficient (IL‐10–/–) mice, a murine model of Crohns disease (CD). SEW2871 was administered by gavage at a dose of 20 mg/kg/day for 2 weeks to IL‐10–/– mice. Severity of colitis, serum amyloid A, tissue myeloperoxidase (MPO), T cells in blood and colon lamina propria (LP) and proinflammatory cytokine productions were evaluated. Furthermore, the phospho‐signal transducer and activator of transcription (STAT)‐3 (p‐STAT‐3) expression in lymphocytes isolated from colon LP was also assessed. The 2‐week administration of SEW2871 ameliorated established colitis in IL‐10–/– mice, associated with a reduction of serum amyloid A concentration, a decreased colon MPO concentration, a depletion of the peripheral CD4+CD45+ T cells and a reduction of the homing of T cells into colon LP. Moreover, typical cytokines of T helper type 1 (Th1) and Th17 cells and p‐STAT‐3 expression were also suppressed by SEW2871 treatment. SEW2871 treatment ameliorates established experimental colitis in IL‐10–/– mice, which may provide a new therapeutic approach for human CD therapy.

Dietary Non-digestible Polysaccharides Ameliorate Intestinal Epithelial Barrier Dysfunction in IL-10 Knockout Mice.

BACKGROUND Enteral nutrition [EN] was reported to be as effective as steroids in achieving short-term remission in patients with Crohns disease [CD], and exclusive EN [EEN] is widely used as primary therapy in children with CD. The aim of this study was to investigate the effect of a specific multi-fibre mix [MF], designed to match the fibre content of a healthy diet, on intestinal epithelial barrier function in IL-10 knockout [IL-10(-/-)] mice with spontaneous chronic colitis. METHODS IL-10(-/-) mice aged 16 weeks, with established colitis, were used for the experiments with multi-fibre mix diet [MF] for 4 weeks. Severity of colitis, levels of short cahin fatty acids [SCFA] in caecum contents, expression of STAT 3 and STAT 4 proteins, CD4(+) CD45(+) lymphocytes, CD4(+)Foxp3(+) regulatory T cells [Tregs] and cytokines in the lamina propria [LP], epithelial expression of tight junction proteins, TNF-α/TNFR2 mRNA expression, and epithelial apoptosis in the proximal colon were measured at the end of the experiment. RESULTS MF feeding effectively attenuated disease activity index and colitis associated with decreased lamina propria CD4(+) CD45(+) lymphocytes, IFN-γ/IL-17A mRNA expression, and p-STAT 3 and p-STAT 4 expression in colonic mucosa of IL-10(-/-) mice [p < 0.05]. Furthermore, CD4(+)Foxp3(+) Tregs in the LP and concentrations of total SCFA, acetate, propionate, and butyrate in the caecum were markedly increased after MF feeding in IL-10(-/-) mice. After MF feeding, increased epithelial expression and correct localisation of tight junction proteins [occludin and zona occludens protein 1], as well as reduced TNF-α/TNFR2 mRNA expression and epithelial apoptosis, were also observed in IL-10(-/-) mice. CONCLUSIONS These results indicated that EEN supplemented with the tested fibre mix, known to modulate the intestinal microbiota composition and SCFA production, could possibly improve efficacy in inducing remission in patients with active CD.

DHA protects against experimental colitis in IL-10-deficient mice associated with the modulation of intestinal epithelial barrier function.

A defect in the intestinal barrier is one of the characteristics of Crohns disease (CD). The tight junction (TJ) changes and death of epithelial cells caused by intestinal inflammation play an important role in the development of CD. DHA, a long-chain PUFA, has been shown to be helpful in treating inflammatory bowel disease in experimental models by inhibiting the NF-κB pathway. The present study aimed at investigating the specific effect of DHA on the intestinal barrier function in IL-10-deficient mice. IL-10-deficient mice (IL-10(-/-)) at 16 weeks of age with established colitis were treated with DHA (i.g. 35.5 mg/kg per d) for 2 weeks. The severity of their colitis, levels of pro-inflammatory cytokines, epithelial gene expression, the distributions of TJ proteins (occludin and zona occludens (ZO)-1), and epithelial apoptosis in the proximal colon were measured at the end of the experiment. DHA treatment attenuated the established colitis and was associated with reduced infiltration of inflammatory cells in the colonic mucosa, lower mean histological scores and decreased levels of pro-inflammatory cytokines (IL-17, TNF-α and interferon-γ). Moreover, enhanced barrier function was observed in the DHA-treated mice that resulted from attenuated colonic permeability, rescued expression and corrected distributions of occludin and ZO-1. The results of the present study indicate that DHA therapy may ameliorate experimental colitis in IL-10(-/-) mice by improving the intestinal epithelial barrier function.

Intestinal dysbacteriosis contributes to decreased intestinal mucosal barrier function and increased bacterial translocation.

The purpose of this study was to determine the effect of colistin‐induced intestinal dysbacteriosis on intestinal mucosal barrier function and bacterial translocation in a mouse model. Colistin or saline was administered orally for 7 days, and populations of viable organisms from the caecal mucosa and its content, the ileal segments, the mesenteric lymph nodes (MLNs) and the internal organs were prepared for examination. In the intestinal dysbacteriosis model, intestinal barrier dysfunction was observed and associated with increased bacterial translocation to extraintestinal sites. The extent of bacterial translocation to the MLNs and internal organs in the colistin group was significantly higher than in the saline group. Colistin‐induced intestinal dysbacteriosis was shown to injure the intestinal mucosa barrier function and increase bacterial dislocation.

Docosahexaenoic Acid Attenuated Experimental Chronic Colitis in Interleukin 10-Deficient Mice by Enhancing Autophagy Through Inhibition of the mTOR Pathway.

Background: In the battle against Crohn’s disease, autophagy stimulation is a promising therapeutic option—one both new and newly rediscovered. In experimental models, docosahexaenoic acid (DHA)—a long-chain polyunsaturated fatty acid—has been demonstrated to be useful in the treatment of inflammatory bowel disease through inhibition of the nuclear factor-&kgr;B pathway. However, the impact of DHA on autophagy in the colon remains unclear. Methods: Mice were divided into 3 groups: wild type (placebo), the interleukin 10 knockout group (IL-10−/−, placebo), and the DHA group (IL-10−/−, DHA). DHA was administered to IL-10−/− mice by gavage at a dosage of 35.5 mg/kg/d for 2 weeks. The severity of colitis, expression of proinflammatory cytokines, expression/distribution of LC3B, and mTOR signaling pathway were evaluated in the proximal colon tissues collected from all mice at the end of the experiment. Results: DHA administration ameliorated experimental colitis in the IL-10−/− mice, as demonstrated by decreased proinflammatory cytokines (TNF-&agr; and IFN-&ggr;), reduced infiltration of inflammatory cells, and lowered histologic scores of the proximal colon mucosa. Moreover, in the DHA-treated mice, enhanced autophagy was observed to be associated with (1) increased expression and restoration of the distribution integrity of LC3B in the colon and (2) inhibition of the mTOR signaling pathway. Conclusion: This study showed that DHA therapy could attenuate experimental chronic colitis in IL-10−/− mice by triggering autophagy via inhibition of the mTOR pathway.

Impact of enteral nutrition on energy metabolism in patients with Crohn’s disease

AIM To investigate the impact of enteral nutrition (EN) on the body composition and metabolism in patients with Crohns disease (CD). METHODS Sixty-one patients diagnosed with CD were enrolled in this study. They were given only EN (enteral nutritional suspension, TPF, non-elemental diet) support for 4 wk, without any treatment with corticosteroids, immunosuppressive drugs, infliximab or by surgical operation. Body composition statistics such as weight, body mass index, skeletal muscle mass (SMM), fat mass, protein mass and inflammation indexes such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and CD activity index (CDAI) were recorded before and after EN support. RESULTS The 61 patients were divided into three groups according to CDAI before and after EN support: A (active phase into remission via EN, n=21), B (remained in active phase before and after EN, n=19) and C (in remission before and after EN, n=21). Patients in group A had a significant increase in SMM (22.11±4.77 kg vs 23.23±4.49 kg, P=0.044), protein mass (8.01±1.57 kg vs 8.44±1.45 kg, P=0.019) and decrease in resting energy expenditure (REE) per kilogram (27.42±5.01 kcal/kg per day vs 22.62±5.45 kcal/kg per day, P<0.05). There was no significant difference between predicted and measured REE in active CD patients according to the Harris-Benedict equation. There was no linear correlation between the measured REE and CRP, ESR or CDAI in active CD patients. CONCLUSION EN could decrease the hypermetabolism in active CD patients by reducing the inflammatory response.

Anti-mouse CD52 monoclonal antibody ameliorates intestinal epithelial barrier function in interleukin-10 knockout mice with spontaneous chronic colitis.

Intestinal inflammation causes tight junction changes and death of epithelial cells, and plays an important role in the development of Crohns disease (CD). CD52 monoclonal antibody (CD52 mAb) directly targets the cell surface CD52 and is effective in depleting mature lymphocytes by cytolytic effects in vivo, leading to long‐lasting changes in adaptive immunity. The aim of this study was to investigate the therapeutic effect of CD52 mAb on epithelial barrier function in animal models of IBD. Interleukin‐10 knockout mice (IL‐10−/−) of 16 weeks with established colitis were treated with CD52 mAb once a week for 2 weeks. Severity of colitis, CD4+ lymphocytes and cytokines in the lamina propria, epithelial expression of tight junction proteins, morphology of tight junctions, tumour necrosis factor‐α (TNF‐α)/TNF receptor 2 (TNFR2) mRNA expression, myosin light chain kinase (MLCK) expression and activity, as well as epithelial apoptosis in proximal colon were measured at the end of the experiment. CD52 mAb treatment effectively attenuated colitis associated with decreased lamina propria CD4+ lymphocytes and interferon‐γ/IL‐17 responses in colonic mucosa in IL‐10−/− mice. After CD52 mAb treatment, attenuation of colonic permeability, increased epithelial expression and correct localization of tight junction proteins (occludin and zona occludens protein‐1), as well as ameliorated tight junction morphology were observed in IL‐10−/− mice. CD52 mAb treatment also effectively suppressed the epithelial apoptosis, mucosa TNF‐α mRNA expression, epithelial expression of long MLCK, TNFR2 and phosphorylation of MLC. Our results indicated that anti‐CD52 therapy may inhibit TNF‐α/TNFR2‐mediated epithelial apoptosis and MLCK‐dependent tight junction permeability by depleting activated T cells in the gut mucosa.

Tripterygium wilfordii Hook F as Maintenance Treatment for Crohn's Disease.

Background:The traditional Chinese medicine, Tripterygium wilfordii Hook F (TwHF) is widely used to treat Crohns disease (CD) in China. Methods:The authors compared different doses of TwHF with mesalazine in 198 patients with CD over a 52-week period. Subjects were randomized to receive mesalazine (3 g/d), low-dose TwHF (1.5 mg·kg−1·d−1), or high-dose TwHF (2.0 mg·kg−1·d−1). Results:A total of 137 patients completed the study. At week 52, a significant lower proportion of patients in the high-dose TwHF group (7/71) had clinical recurrence compared with patients in the low-dose TwHF (15/68, P = 0.047) or mesalazine group (17/59, P = 0.006), whereas the difference between the low-dose TwHF group and the mesalazine group was not significant (P = 0.503). Patients receiving mesalazine experienced less adverse events than those receiving high-dose TwHF (P = 0.029) and those receiving low-dose TwHF (P = 0.048), but no significant difference was found about drug adverse events resulted withdrawal in the 3 groups (P > 0.05). In addition, compared with low-dose TwHF and mesalazine, the authors also detected significant superiority of high-dose TwHF arm in the decrease of CDAI and SESCD (P < 0.05). Conclusion:A 2.0 mg/kg daily TwHF was well tolerated and prolonged remission in patients with CD.

Laquinimod ameliorates spontaneous colitis in interleukin-10-gene-deficient mice with improved barrier function.

BACKGROUND AND AIMS Crohns disease is an autoimmune disease associated with imbalanced mucosal immunity, mediated with increased Th1 and Th17 cells. Laquinimod, an immunomodulatory drug, has shown efficacy in regulating the differentiation of T cells. The aim of the study was to investigate the therapeutic effect of laquinimod on spontaneous colitis in interleukin-10-gene-deficient mice, an animal model of Crohns disease. METHODS Male Il10(-/-) mice aged 16weeks in the laquinimod group were treated with laquinimod with distilled water at a dose of 25mg/kg by oral gavage, 3 times a week. Il10(-/-) mice in the IL-10-KO group and wild type mice received equal volume of phosphate buffered saline by oral gavage, 3 times a week. After 4weeks, mice were sacrificed for analysis. Severity of colitis, epithelial expression of T-cell-associated cytokines, expression and distribution of tight junction proteins in the lamina propria and NF-κB signaling pathway associated mRNA expression were measured at the end of the experiment. RESULTS Laquinimod treatment ameliorated spontaneous colitis in Il10(-/-) mice, which was associated with decreased T-cell-associated pro-inflammatory cytokines. Increased expression and correct distribution of tight junction proteins (occludin and ZO-1) were found in Il10(-/-) mice treated with laquinimod. In addition, in mice treated with laquinimod, NF-κB signaling pathway associated mRNA in the colon was also downregulated. CONCLUSIONS Our results indicated that laquinimod treatment ameliorates colitis in Il10(-/-) mice and improves intestinal barrier function, which may support a new therapeutic approach to Crohns disease.