Akira Andoh

Increased expression of interleukin 17 in inflammatory bowel disease

Background and aim: Interleukin (IL) 17 is a cytokine which exerts strong proinflammatory activities. In this study we evaluated changes in IL-17 expression in the inflamed mucosa and in the serum of patients with inflammatory bowel disease (IBD). Methods: Tissue samples were obtained endoscopically or surgically from patients with ulcerative colitis (UC) (n=20), Crohn’s disease (CD) (n=20), infectious colitis (n=5), ischaemic colitis (n=8), and normal colorectal tissues (n=15). IL-17 expression was evaluated by a standard immunohistochemical procedure. Serum IL-17 levels were determined by ELISA. IL-17 mRNA expression was analysed by reverse transcriptase-polymerase chain reaction. Results: IL-17 expression was not detected in samples from normal colonic mucosa, infectious colitis, or ischaemic colitis. In the inflamed mucosa of active UC and CD patients, IL-17 expression was clearly detectable in CD3+ T cells or CD68+ monocytes/macrophages. The average number of IL-17+ cells was significantly increased in active UC and CD patients compared with inactive patients. IL-17 mRNA expression was not detected in normal mucosa but was detectable in the mucosa from active UC and CD patients. IL-17 was not detected in the sera from normal individuals, infectious colitis, or ischaemic colitis patients but IL-17 levels were significantly elevated in IBD patients. Conclusions: IL-17 expression in the mucosa and serum was increased in IBD patients. It is likely that IL-17 expression in IBD may be associated with altered immune and inflammatory responses in the intestinal mucosa.

IL-22 ameliorates intestinal inflammation in a mouse model of ulcerative colitis

Expression of IL-22 is induced in several human inflammatory conditions, including inflammatory bowel disease (IBD). Expression of the IL-22 receptor is restricted to innate immune cells; however, the role of IL-22 in colitis has not yet been defined. We developed what we believe to be a novel microinjection-based local gene-delivery system that is capable of targeting the inflamed intestine. Using this approach, we demonstrated a therapeutic potency for IL-22-mediated activation of the innate immune pathway in a mouse model of Th2-mediated colitis that induces disease with characteristics similar to that of IBD ulcerative colitis (UC). IL-22 gene delivery enhanced STAT3 activation specifically within colonic epithelial cells and induced both STAT3-dependent expression of mucus-associated molecules and restitution of mucus-producing goblet cells. Importantly, IL-22 gene delivery led to rapid amelioration of local intestinal inflammation. The amelioration of disease by IL-22 was mediated by enhanced mucus production. In addition, local gene delivery was used to inhibit IL-22 activity through overexpression of IL-22-binding protein. Treatment with IL-22-binding protein suppressed goblet cell restitution during the recovery phase of a dextran sulfate sodium-induced model of acute colitis. These data demonstrate what we believe to be a novel function for IL-22 in the intestine and suggest the potency of a local IL-22 gene-delivery system for treating UC.

Epithelial overexpression of interleukin-32α in inflammatory bowel disease

Interleukin (IL)‐32 is a recently described proinflammatory cytokine, characterized by induction of nuclear factor (NF)‐κB activation. We studied IL‐32α expression in the inflamed mucosa of inflammatory bowel disease (IBD). We also investigated mechanisms regulating IL‐32α expression. Tissue samples were obtained endoscopically or surgically from patients with ulcerative colitis (UC) (n = 10), Crohns disease (CD) (n = 10), ischaemic colitis (n = 4) and normal colorectal tissues (n = 10). IL‐32α expression was evaluated by standard immunohistochemical procedure. IL‐32 mRNA expression was analysed by Northern blot. IL‐32α was expressed weakly by colonic epithelial cells from normal individuals and subjects with ischaemic colitis. In the inflamed mucosa of IBD patients, epithelial IL‐32α expression was increased markedly. In UC and CD patients, IL‐32α expression was enhanced in affected mucosa compared to non‐affected mucosa. In intestinal epithelial cell lines, expression of IL‐32α mRNA and protein was enhanced by IL‐1β, interferon (IFN)‐γ and tumour necrosis factor (TNF)‐α. A combination of TNF‐α plus IFN‐γ exerted synergistic effects. IL‐32α induction by IL‐1β and/or TNF‐α was mediated by NF‐κB activation. Epithelial IL‐32α expression was increased in IBD patients, and in CD patients in particular. IL‐32α might be involved in the pathophysiology of IBD as a proinflammatory cytokine and a mediator of innate immune response.

Interleukin-33 expression is specifically enhanced in inflamed mucosa of ulcerative colitis

BackgroundInterleukin (IL)-33 is a cytokine belonging to the IL-1 family. IL-33 has been shown to elicit a Th2-like cytokine response in immune cells. In this study, we investigated IL-33 expression in the inflamed mucosa of patients with inflammatory bowel disease (IBD), and characterized the molecular mechanisms responsible for IL-33 expression in human colonic subepithelial myofibroblasts (SEMFs).MethodsIL-33 mRNA expression was determined by real-time polymerase chain reaction (PCR). IL-33 expression in the IBD mucosa was evaluated by immunohistochemical methods.ResultsIL-33 mRNA expression was significantly elevated in active lesions from patients with ulcerative colitis (UC), but was not detected in inactive lesions from UC patients or in lesions from patients with either active or inactive Crohn’s disease. Colonic SEMFs were identified as a major source of IL-33 in the mucosa. IL-1β and tumor necrosis factor-α (TNF-α) significantly enhanced IL-33 mRNA and protein expression in isolated colonic SEMFs. IL-1β and TNF-α did not affect IL-33 expression in intestinal epithelial cell lines (HT-29 and Caco-2 cells). This IL-1β- and TNF-α-induced IL-33 mRNA expression was mediated by p42/44 mitogen activated protein kinase (MAPK) pathway-dependent activation of nuclear factor (NF)-κB and activator protein (AP)-1.ConclusionsIL-33, derived from colonic SEMFs, may play an important role in the pathophysiology of UC.

Treatment of ulcerative colitis by feeding with germinated barley foodstuff: first report of a multicenter open control trial

Background. Germinated barley foodstuff (GBF) is a prebiotic foodstuff that effectively increases luminal butyrate production by stimulating the growth of protective bacteria. In the first pilot study, GBF has been shown to reduce both clinical activity and mucosal inflammation in ulcerative colitis (UC). The aim of this study was to investigate the efficacy of GBF in the treatment of UC in a multicenter open control trial. Methods. Eighteen patients with mildly to moderately active UC were divided into two groups using a random allocation protocol. The control group (n = 7) were given a baseline anti-inflammatory therapy for 4 weeks. In the GBF-treated group (n = 11), patients received 20–30 g GBF daily, together with the baseline treatment, for 4 weeks. The response to the treatments was evaluated clinically and endoscopically. Fecal micro-flora were also analyzed. Results. After 4 weeks of observation, the GBF-treated group showed a significant decrease in clinical activity index scores compared with the control group (P < 0.05). No side effects related to GBF were observed. GBF therapy increased fecal concentrations of Bifidobacterium and Eubacterium limosum. Conclusions. Oral GBF therapy may have the potency to reduce clinical activity of UC. We believe that these results support the use of GBF administration as a new adjunct therapy for UC.

Role of Dietary Fiber and Short-Chain Fatty Acids in the Colon

Luminal nutrition is important for maintenance of gastrointestinal mucosal structure and function. In particular, short chain fatty acids (SCFAs), metabolic products of anaerobic bacterial fermentation of dietary fiber and resistant starch, are particularly important as the preferred respiratory fuel of the colonocytes. A variety of biological effects of SCFAs have been reported, and there is now increasing number of experimental works showing new aspects of these molecules. For example, as the mechanisms mediating anti-inflammatory effects of SCFAs, several investigators identified the inhibitory effect of butyrate on proinflammatory cytokine-induced NF-kappaB activation. Various inflammatory responses are now discussed with the central role of NF-kappaB activation, and thus the inhibition of NF-kappaB activation represents the efficacy of dietary fiber and SCFAs in the treatment with inflammatory bowel disease. Furthermore, recent advance in molecular technology has identified mechanisms mediating anti-tumor effects of SCFAs. SCFAs modulate expression of cell cycle-regulating proteins and induce apoptosis in colon cancer cells. SCFAs increase the susceptibility of colon cancer cells to complement-mediated cell injury. In this review, new aspects of functions of SCFAs are focused and summarized.

IL-6 Secretion by Human Pancreatic Periacinar Myofibroblasts in Response to Inflammatory Mediators

There is increasing evidence that IL-6 plays an important role in the pathophysiology of acute pancreatitis via its broad proinflammatory actions. To identify the local biosynthetic site for IL-6 in human pancreas, we investigated IL-6 secretion in human pancreatic periacinar myofibroblasts. IL-6 secretion was determined by ELISA and Northern blotting. The activation of NF-κB was assessed by EMSA. The activation of mitogen-activated protein kinase (MAPK) was assessed by immunoblotting. IL-6 secretion was rapidly induced by IL-17, IL-1β, and TNF-α. EMSAs demonstrated that IL-17, IL-1β, and TNF-α induced NF-κB activation within 1.5 h after stimulation, and a blockade of NF-κB activation by the pyrrolidine derivative of dithiocarbamate and tosyl-phe-chloromethylketone markedly reduced the IL-17-, IL-1β-, or TNF-α-induced IL-6 gene expression. Furthermore, IL-17, IL-1β, and TNF-α induced a rapid activation of extracellular signal-related kinase p42/44 and p38 MAPKs, and specific MAPK inhibitors (SB203580, PD98059, and U0216) significantly reduced IL-17-, IL-1β-, or TNF-α-induced IL-6 secretion, indicating the role of MAPKs in the induction of IL-6. The combination of either IL-17 plus IL-1β or IL-17 plus TNF-α enhanced IL-6 secretion and IL-6 mRNA expression; in particular, the effects of IL-17 plus TNF-α were much stronger than those induced by IL-17 plus IL-1β. TNF-α-induced IL-6 mRNA degraded rapidly at any concentrations, and the combination of IL-17 and TNF-α markedly enhanced IL-6 mRNA stability. This indicates that the effects of IL-17 plus TNF-α were regulated at the post-transcriptional level. In conclusion, pancreatic periacinar myofibroblasts secreted a large amount of IL-6 in response to proinflammatory cytokines. These cells might play an important role in the pathogenesis of acute pancreatitis via IL-6 secretion.

Comparison of the fecal microbiota profiles between ulcerative colitis and Crohn’s disease using terminal restriction fragment length polymorphism analysis

BackgroundTerminal restriction fragment length polymorphism (T-RFLP) analysis is a powerful tool to assess the diversity of a microbial community. In this study, we performed T-RFLP analysis of the fecal microbiota from patients with ulcerative colitis (UC) and those with Crohn’s disease (CD).MethodsThirty-one patients with UC, 31 patients with CD, and 30 healthy individuals were enrolled. The polymerase chain reaction (PCR) products obtained from the 16S rRNA genes of fecal samples were digested with BslI, and T-RF lengths were determined.ResultsThe fecal microbial communities were classified into 5 clusters. Twenty-eight of the 30 healthy individuals and 17 of the 18 patients with inactive UC were classified into clusters I, II, and III, but these clusters included a small number of patients with active UC and inactive/active CD. In contrast, 8 of the 13 patients with active UC and the majority of CD patients (12 of the 16 patients with inactive CD, and 11 of the 15 patients with active CD) were included in clusters IV and V. Based on the BslI-digested T-RFLP database, the bacteria showed a significant decrease in the Clostridium family in patients with active UC and inactive/active CD. In contrast, Bacteroides were significantly increased in CD patients. No significant differences were observed between patients with active UC and those with active CD.ConclusionThe fecal microbial communities of IBD patients were different from those of healthy individuals. The gut microbiota of patients with inactive UC tended to be closer to that of healthy individuals, suggesting different roles for the fecal microbiota in the pathophysiology of UC and CD.

A new prebiotic from germinated barley for nutraceutical treatment of ulcerative colitis

Abstract  A germinated barley foodstuff (GBF) containing glutamine‐rich protein and hemicellulose‐rich fiber was made from brewers spent grain, by physical isolation. Our previous studies demonstrated that GBF supported maintenance of epithelial cell populations, facilitated epithelial repair, and suppressed epithelial nuclear factor κB‐DNA‐binding activity through generating increased short‐chain fatty acid (especially butyrate) production by luminal microflora, which includes Bifidobacterium and Eubacterium, thereby preventing experimental colonic injury. The fiber fraction also modulates stool water content because of its high water‐holding capacity. The patients with mild to moderate active ulcerative colitis who had been unresponsive to or intolerant of standard treatment received 20–30 g GBF, feeding daily in a non‐randomized, open‐label fashion. At 4 weeks, this treatment resulted in a significant clinical and endoscopic improvement. The improvement was associated with an increase in stool butyrate concentrations. These results indicate that GBF feeding is a potentially new, attractive prebiotic treatment in patients with ulcerative colitis. The potency of GBF on modulating microflora, as well as the high water‐holding capacity, may play an important role in treatment and prolongation of remission in ulcerative colitis.

Physiological and anti-inflammatory roles of dietary fiber and butyrate in intestinal functions.

BACKGROUND We investigated the effects of pectin, a soluble dietary fiber, on the morphological parameters of the small intestine. In addition, we tested the effects of butyrate enemas on dextran sulfate sodium (DSS)-induced experimental colitis. METHODS Male Wistar rats were fed an elemental diet containing 2.5% pectin for 14 days, and several parameters were then determined. DSS-induced colitis was evoked by the oral administration of water containing 3% DSS for 10 days. The butyrate enema (3 mL of 100 mmol/L butyrate per day) was begun 7 days before the DSS treatment. Interleukin (IL)-8 secretion in the human intestinal epithelial cell line HT-29 was determined by enzyme-linked immunosorbent assay (ELISA). RESULTS Pectin feeding induced a significant increase in the villus height and crypt depth in the small intestine. These effects correlated with a significant increase in plasma enteroglucagon levels. Pretreatment with a butyrate enema significantly blocked the development of DSS-induced experimental colitis. In the in vitro experiment, sodium butyrate dose-dependently inhibited tumor necrosis factor (TNF)-alpha-induced IL-8 secretion in HT-29 cells. CONCLUSIONS A trophic effect due to dietary fiber was directly observed. The generation of short-chain fatty acids and the induction of enteroglucagon release might play an important role in this process. Butyrate, one of the major metabolites of dietary fiber, exerted a potent anti-inflammatory effect both in vivo and in vitro. Dietary fiber may therefore play important roles in the regulation of normal and pathological conditions in the intestine.