Minimizing infliximab toxicity in the treatment of inflammatory bowel disease

Natural Products as Dietary Agents for the Prevention and Mitigation of Oxidative Damage and Inflammation in the Intestinal Barrier

Food intake is a basic need to sustain life, but foodborne pathogens and food-related xenobiotics are also the main health concerns regarding intestinal barrier homeostasis. With a predominant role in the well-being of the entire human body, intestinal barrier homeostasis is strictly regulated by epithelial and immune cells. These cells are also the main intervenients in oxidative stress and inflammation-related diseases in the intestinal tract, triggered, for example, by genetic/epigenetic factors, food additives, pesticides, drugs, pathogens, and their metabolites. Nevertheless, the human diet can also be seen as a solution for the problem, mainly via the inclusion of functional foods or nutraceuticals that may act as antioxidant/anti-inflammatory agents to prevent and mitigate acute and chronic oxidative damage and inflammation. A literature analysis of recent advances in this topic highlights the significant role of Nrf2 (nuclear factor erythroid 2-related factor 2) and NF-kB (nuclear factor kappa-light-chain-enhancer of activated B cells) pathways in these biological processes, with many natural products and phytochemicals targeting endogenous antioxidant systems and cytokine production and balance. In this review, we summarized and discussed studies using in vitro and in vivo models of the intestinal tract used to reproduce oxidative damage and inflammatory events, as well as the role of natural products as modulators of Nrf2 and NK-kB pathways.

Reversing Ongoing Chronic Intestinal Inflammation and Fibrosis by Sustained Block of IL-12 and IL-23 Using a Vaccine in Mice

Interleukin (IL)-12 and IL-23 that share subunit p40 are important cytokines in the pathogenesis of inflammatory bowel disease. We reported that mouse p40 peptide-based vaccines ameliorated intestinal inflammation in the prevention of trinitrobenzene sulfonic acid (TNBS)–induced murine colitis model. Here, we evaluated whether administration of the vaccine after establishment of colitis would be effective in modifying both TNBS-induced and dextran sulfate sodium (DSS)–induced chronic colitis and the underlying immune mechanisms. We further examined whether vaccination could exacerbate infections. Chronic colitis was developed by either intrarectally administrating TNBS or drinking 4% DSS water. Vaccination started after two TNBS administrations or 7 days of DSS treatment. Results showed that administrating p40 vaccine induced high tittered antibodies to IL-12 and IL-23, improved clinical scores, reduced intestinal inflammation and fibrosis, and down-regulated proinflammatory cytokine productions in colon tissue, compared with control mice. Furthermore, in lamina propria mononuclear cells and/or mesenteric lymph nodes, mice immunized with p40 peptide vaccine exhibited high ratios of Treg/Th1 and Treg/Th17 cells and increased IL-10 expression in CD11c⁺IL-10⁺cells. In mice infected with lung chlamydia, in which the protective role of Th1/Th17 is well documented, vaccine immunization did not increase lung bacterial burden. We conclude that p40 vaccine may provide a potential and safe approach for treatment of IBD.

Cytokine expression and the role of Thl7 cells in mice colitis

BACKGROUND/AIMS

To explore the expression and mechanism of Thl7 cells and cytokines in mice model with 2,4,6-trinitrobenzenesulphonic acid (TNBS)-induced inflammatory bowel disease (IBD).

METHODOLOGY

ELISA assay was used to detect the expression of Th17 cytokine IL-17 and Thl cytokines IFN-y in colon tissues. Western blot assay was applied to detect IL-17 expression in peripheral blood mononuclear cells (PBMC), spleen mononuclear cells (SMC), mesenteric lymph node cells and colon tissue of colitic mice. RT-PCR assay was used to detect the effect of anti-IL-17 antibody application on TNF-a, IFN-y and IL-6 mRNA levels in SMCs from colitic mice.

RESULTS

Th17 cytokine IL-17 and Thl cytokines IFN-y were both expressed at high level in TNBS-induced colitic mice. In addition, the expression of Thl7 cytokine appeared earlier than the Thl cytokine. IL-17 levels in SMCs, mesenteric lymph node cells and colon tissue of the disease model group had significant differences compared with normal control group (p<0.01), while the IL-17 level in PBMCs of the disease model group had no significant difference (p>0.05) to control group. After application of 10 ug/mL anti-IL-7 antibody, the TNF-ct, IL-6 and IFN-y mRNA levels in SMCs of the model group showed no significant difference from that of no antibody group (p>0.05).

CONCLUSIONS

Both Th17 cells and Thl cells involved in TNBS-induced IBD and the role of Thl17 cells may be through inducing the secretion of pro-inflammatory cytokines.

[Guidelines for the management of ulcerative colitis]

Ulcerative colitis (UC) is a chronic inflammatory bowel disorder characterized by a relapsing and remitting course. The quality of life can decreases significantly during exacerbations of the disease. The incidence and prevalence of UC in Korea are still lower than those of Western countries, but have been rapidly increasing during the past decades. Various medical and surgical therapies are currently used for the management of UC. However, many challenging issues exist and sometimes these lead to differences in practice between clinicians. Therefore, Inflammatory Bowel Diseases (IBD) Study Group of Korean Association for the Study of Intestinal Diseases (KASID) set out the Korean guidelines for the management of UC. These guidelines are made by the adaptation using several foreign guidelines and encompass treatment of active colitis, maintenance of remission and indication for surgery in UC. The specific recommendations are presented with the quality of evidence. These are the first Korean treatment guidelines for UC and will be revised with new evidences on treatment of UC.

Anti-tumor necrosis factor-α monoclonal antibody alleviates parenteral nutrition-associated liver disease in mice

BACKGROUND

The authors aimed to investigate the role of anti-tumor necrosis factor (TNF)-α monoclonal antibody treatment in a mouse model of parenteral nutrition-associated liver disease (PNALD).

METHODS

C57BL/6J male mice (aged 6-8 weeks) were randomly assigned to 3 groups: parenteral nutrition (PN), PN with anti-TNF-α monoclonal antibody treatment (PN + mAb), and controls. A central venous catheter was inserted for intravenous infusion of a PN solution (PN and PN + mAb groups) or saline (controls) for 7 days. Liver pathology, hepatic biochemical indicators, and serum TNF-α concentrations were analyzed. Levels of hepatic bsep, mdr1a/mdr1b, mdr2, and mrp2 mRNA were also evaluated in each group.

RESULTS

The PN group showed significant increases in serum transaminase, direct bilirubin, and bile acids relative to the control group (P < .05). Histopathological changes in this group were consistent with early stage cholestasis. The pathological score and serum alanine aminotransferase, total bilirubin, and direct bilirubin levels were improved in the PN + mAb group relative to the PN group (P < .05). The PN group showed significantly lower hepatic bsep, mdr1a/mdr1b, mdr2, and mrp2 mRNA expression than the controls (P < .05), but these were significantly increased compared to the PN group (P < .05).

CONCLUSIONS

Infliximab administered at a single dose of 5 mg/kg body weight ameliorated the progression of PNALD and improved the expression of hepatic ABC transporter genes. Therefore, anti-TNF-α monoclonal antibody may be a beneficial therapy for patients with PNALD.

Targeting IL-12/IL-23 by employing a p40 peptide-based vaccine ameliorates TNBS-induced acute and chronic murine colitis

Interleukin (IL)-12 and IL-23 both share the p40 subunit and are key cytokines in the pathogenesis of Crohn's disease. Previously, we have developed and identified three mouse p40 peptide-based and virus-like particle vaccines. Here, we evaluated the effects and immune mechanisms of the optimal vaccine in downregulating intestinal inflammation in murine acute and chronic colitis, induced by intrarectal administrations of trinitrobenzene sulfonic acid (TNBS). Mice were injected subcutaneously with vaccine, vaccine carrier or saline three times, and then intrarectally administered TNBS weekly for 2 wks (acute colitis) or 7 wks (chronic colitis). The severity of colitis was evaluated by body weight, histology and collagen and cytokine levels in colon tissue. Th1 and Th17 cells in mesenteric lymph nodes (MLN) were determined. Our results showed the vaccine induced high level and long-lasting specific IgG antibodies to p40, IL-12 and IL-23. After administrations of TNBS, vaccinated mice had significantly less body weight loss and a significant decrease of inflammatory scores, collagen deposition and expression of p40, IL-12, IL-23, IL-17, TNF, iNOS and Bcl-2 in colon tissues, compared with carrier and saline groups. Moreover, vaccinated mice exhibited a trend to lower percentages of Th1 cells in acute colitis and of Th17 cells in chronic colitis in MLN than in controls. In summary, administration of the vaccine induced specific antibodies to IL-12 and IL-23, which was associated with improvement of intestinal inflammation and fibrosis. This suggests that the vaccine may provide a potential approach for the long-term treatment of Crohn's disease.