Yoshitaka Kinouchi

Crohn's disease is associated with novel polymorphisms in the 5'-flanking region of the tumor necrosis factor gene.

BACKGROUND & AIMSnTumor necrosis factor (TNF) is considered to play an important role in the pathogenesis of Crohns disease (CD). Recently, 3 polymorphisms in the 5-flanking region of the TNF gene at positions -1031, -863, and -857, which are related to high transcriptional promoter activity, have been identified in the Japanese population. In an effort to understand potential genetic association with CD, we evaluated patients diagnosed with CD and ulcerative colitis (UC) in the presence of other novel polymorphisms.nnnMETHODSnBlood samples were obtained from 103 patients with CD and 76 patients with UC. Polymorphisms in the TNF gene at their respective positions were analyzed by direct sequencing, and the allele frequencies were compared with those determined previously in a healthy Japanese population.nnnRESULTSnAllele frequencies of -1031C, -863A, and -857T in normal controls were 16.0%, 14.0%, and 17.7%, respectively. Polymorphic allele frequencies at positions -1031, -863, and -857 were 24.3%, 21.8%, and 27.2% in CD and 11.8%, 11.2%, and 11.8% in UC, respectively. The frequencies at all 3 positions were significantly higher in CD patients than in UC patients or healthy controls. Among the subgroups of CD, small bowel disease showed the highest frequencies.nnnCONCLUSIONSnAlthough the findings need to be confirmed in other populations with larger numbers of patients, TNF gene polymorphisms -1031C, -863A, and -857T are positively associated with CD; they may influence not only the susceptibility to CD but also the disease location.

A genome-wide association study identifies three new susceptibility loci for ulcerative colitis in the Japanese population

Ulcerative colitis is one of the principal forms of inflammatory bowel disease with complex manifestations. Although previous studies have indicated that there is a genetic contribution to the pathogenesis of ulcerative colitis, the genes influencing susceptibility to the disease have not been fully determined. To identify genetic factors conferring risk of ulcerative colitis, here we conducted a two-stage genome-wide association study and subsequent replication study using 1,384 Japanese individuals with ulcerative colitis and 3,057 control subjects. In addition to the expected strong association with the major histocompatibility complex (MHC) region, we identified three new susceptibility loci: the immunoglobulin receptor gene FCGR2A (rs1801274, P = 1.56 × 10−12), a locus on chromosome 13q12 (rs17085007, P = 6.64 × 10−8) and the glycoprotein gene SLC26A3 (rs2108225, P = 9.50 × 10−8). rs1801274 is a nonsynonymous SNP of FCGR2A that is reported to have a critical effect on receptor binding affinity for IgG and to be associated with other autoimmune diseases. Our findings provide insight into the molecular pathogenesis of ulcerative colitis.

TNFSF15 transcripts from risk haplotype for Crohn's disease are overexpressed in stimulated T cells

TNFSF15 is a susceptibility gene for Crohns disease (CD). It remains to be elucidated how the associated single nucleotide polymorphisms (SNPs) in TNFSF15 affect the susceptibility to CD. Because there are no non-synonymous SNPs in TNFSF15, we speculated that one or more of the SNPs associated with CD may act as cis-regulatory SNPs. To reveal the effects of the SNPs on the transcriptional activity of TNFSF15, we first examined the allelic expression imbalance of TNFSF15 in peripheral blood mononuclear cells (PBMCs). When PBMCs stimulated by phytohemagglutinin (PHA) were examined, the allelic ratio of mRNA transcribed from the risk haplotype to the non-risk haplotype increased, compared with the ratio without stimulation. When peripheral blood T cells and Jurkat cells stimulated by phorbol 12-myristate 13-acetate + ionomycin were examined, an allelic expression imbalance similar to that observed in PBMCs stimulated by PHA was confirmed. The promoter assay in stimulated Jurkat cells showed that the luciferase activity of the promoter region (-979 to +35) of the risk haplotype was significantly higher than that of the non-risk haplotype, and deletion and mutagenesis analysis demonstrated that this difference resulted from the -358T/C SNP. The promoter activity of -358C (risk allele) was higher than that of -358T (non-risk allele) in stimulated T cells. This effect of -358T/C on the transcriptional activity in stimulated T cells may confer susceptibility to CD.

Telomere shortening and the clinicopathologic characteristics of human colorectal carcinomas

It has been reported that shortening of telomeres and strong activation of telomerase occur frequently in colorectal carcinomas. In the current study, the authors examined the correlations between the telomere length of colorectal carcinomas and their clinicopathologic characteristics as well as the activity of telomerase to clarify whether telomere length might represent the biologic behavior of tumors and the mode of tumor development.

C-reactive protein is an indicator of serum infliximab level in predicting loss of response in patients with Crohn’s disease

BackgroundThe ability of serum infliximab level to predict clinical outcome in infliximab therapy in Crohn’s disease is unclear. Here, we aimed to clarify the correlation between the timing of loss of response (LOR) to treatment and a decrease in serum infliximab level, and, in addition, to identify an indicator of infliximab level.MethodsThe study used data from a previous clinical study of infliximab for Crohn’s disease, in which infliximab was initially given at 0, 2, 6xa0weeks at 5xa0mg/kg, and then at 8-week intervals to 62xa0week-10 responders. Of these 62, here we analysed data from 57 in whom Crohn’s disease activity index and serum infliximab level were evaluated at week 14.ResultsTwelve patients showed a clinical response despite an infliximab level <1xa0μg/mL at week 14; of these, 8 (67xa0%) experienced LOR by week 54. A decrease in infliximab level preceded LOR in 6 (75xa0%). In receiver operating characteristic curve analysis, C-reactive protein (CRP) showed better performance in detecting an infliximab level <1xa0μg/mL. Infliximab level was <1xa0μg/mL in 60–80xa0% of patients with CRP >0.5xa0mg/dL. Time to LOR (median: 22.0xa0weeks) was significantly longer than that to a decrease in infliximab level to <1xa0μg/mL (14.0xa0weeks, pxa0<xa00.05) or to an increase in CRP to >0.5xa0mg/dL (14.0xa0weeks, pxa0<xa00.01).ConclusionsA decrease in serum infliximab level preceded LOR, and was easily detected by an increase in CRP. The CRP may be an indicator of serum infliximab level in predicting LOR.

Retrieval of serum infliximab level by shortening the maintenance infusion interval is correlated with clinical efficacy in Crohn's disease.

Background: Infliximab has shown beneficial effects in the treatment of Crohns disease (CD). The aim of this study was to assess 1) the clinical efficacy of shortening the infusion interval from 8 to 4 weeks when patients had shown loss of response during maintenance therapy, and 2) the association between the serum trough level and clinical efficacy. Methods: This was an open‐label prospective multicenter study. Infliximab was administered at 5 mg/kg to patients with active CD at weeks 0, 2, and 6. Week 10 responders received infliximab every 8 weeks thereafter. In those with loss of response after week 14 the interval was switched to every 4 weeks. Co‐primary endpoints were the rate of patients achieving clinical response and remission at week 54. Serum level of infliximab was measured at each visit. Results: Fifty‐seven patients who responded to induction treatment received maintenance therapy after week 14. Thirty‐seven patients continued at the 8‐week interval and 20 patients were switched to a 4‐week interval. The overall clinical response and remission rates at week 54 were 82.5% and 61.4%, respectively. For those with loss of response, treatment at the 4‐week interval resulted in clinical response and remission rates of 83.3% (15/18) and 55.6% (10/18), respectively, at week 54. A correlation between clinical efficacy and serum trough level was found (P < 0.01, overall). Conclusions: A treatment strategy with an option of shortening the dosing interval of infliximab retrieves its trough level and may be useful for maintaining its efficacy. (Inflamm Bowel Dis 2012)

Changes of faecal microbiota in patients with Crohn's disease treated with an elemental diet and total parenteral nutrition.

BACKGROUNDnIntestinal microbiota contributes to the pathogenesis of Crohns disease. Elemental diet and total parenteral nutrition are effective therapies for Crohns disease; however, changes of microbiota as a result of both treatments have not been fully elucidated.nnnAIMnTo elucidate changes of faecal microbiota in Crohns disease patients treated with elemental diet and total parenteral nutrition.nnnMETHODSnStool samples were collected from 33 active Crohns disease patients and 17 healthy subjects, and recollected after elemental diet (8 patients) and total parenteral nutrition (9 patients). Terminal restriction fragment length polymorphism analysis of bacterial 16srDNA was performed to evaluate the whole microbiota. Specific quantitative PCR was then used to determine populations of predominant bacterial groups.nnnRESULTSnIn Crohns disease patients, the number of terminal restriction fragments, which reflects bacterial species, was significantly lower. Populations of total bacteria and Bifidobacterium were significantly lower and the ratio of Enterococcus was higher. The number of terminal restriction fragments was significantly decreased after total parenteral nutrition, but not after elemental diet. Population of Bacteroides fragilis significantly decreased after elemental diet, while population of Enterococcus significantly increased after total parenteral nutrition.nnnCONCLUSIONnFaecal microbiota in Crohns disease patients was markedly different from healthy subjects. Species diversity was reduced by total parenteral nutrition, but not by elemental diet.

Short and long-term outcomes of endoscopic balloon dilatation for Crohn’s disease strictures

AIMnTo investigate the short and long-term outcomes of endoscopic balloon dilatation (EBD) for Crohns disease (CD) strictures.nnnMETHODSnBetween January 1995 and December 2011, 47 EBD procedures were performed in 30 patients (8 females and 22 males) with CD. All patients had strictures through which an endoscope could not pass, and symptoms of these strictures included abdominal pain, abdominal fullness, nausea, and/or vomiting. The 47 strictures included 17 anastomotic and 30 de novo strictures. Endoscopy and dilatation were performed under conscious sedation with intravenous diazepam or flunitrazepam. The dilatations were all performed using through-the-scope balloons with diameters from 8 mm to 20 mm on inflation and lengths of 30-80 mm. Each dilatation session consisted of two to four, 3-min multistep inflations of the balloon, repeated at intervals of 1 wk until adequate dilatation (up to 15-20 mm in diameter) was achieved. The follow-up data were collected from medical records and analyzed retrospectively. Primary success was defined as passage of the scope through the stricture after EBD. Long-term outcomes were analyzed focusing on intervention-free survival and surgery-free survival demonstrated by the Kaplan-Meier method. (Intervention-free meant cases in which neither endoscopic balloon re-dilatation nor surgery was needed after the first dilatation during the observation period). The log rank test was used to evaluate the difference in long-term outcomes between anastomotic and de novo stricture cases.nnnRESULTSnPrimary success was achieved in 44 of the 47 strictures (93.6%). Balloon dilatations failed in 3 cases (6.4%). In 1 case, EBD was a technical failure because the guide-wire could not be passed through the stricture which showed severe adhesion and was a flexural lesion of the intestine. In 2 cases, unexpected perforations occurred immediately after balloon dilatation. Of the 47 treatments, complications occurred in 5 (10.6%). All 5 patients had de novo strictures. One suffered bleeding, two high fever and there were colorectal perforations. One of the patients with a colorectal perforation was treated surgically, the other was managed conservatively. These 2 cases correspond to the two aforementioned EBD failures. Long-term outcomes were evaluated for the 44 successfully-treated strictures after a median follow-up of 26 mo (range, 2-172 mo). During the observation period, re-strictures after EBDs occurred in 26 cases (60.5%). Fourteen of these 26 re-stricture cases underwent EBD again, but in two EBD failed and surgery was ultimately performed in both cases. Twelve of the 26 re-stricture cases were initially treated surgically when the re-strictures occurred. Finally, 30 of the 47 strictures (63.8%) were successfully managed with EBD, allowing surgery to be avoided. Intervention-free survival evaluated by the Kaplan-Meier method was 75% at 12 mo, 58% at 24 mo, and 43% at 36 mo. There was no significant difference between the anastomotic strictures (n = 16) and de novo strictures (n = 28) in the intervention-free survival as evaluated by the log-rank test. Surgery-free survival evaluated by the Kaplan-Meier method was 90% at 12 mo, 75% at 24 mo, and 53% at 36 mo. The 16 anastomotic strictures were associated with significantly better surgery-free survivals than the 28 de novo strictures (log-rank test: P < 0.05).nnnCONCLUSIONnAnastomotic strictures were associated with better long-term outcomes than de novo strictures, indicating that stricture type might be useful for predicting the long-term outcomes of EBD.

Successful treatment of cap polyposis by avoidance of intraluminal trauma: clues to pathogenesis

“Cap polyposis” is a rarely-encountered condition in which distinctive inflammatory polyps are located from the rectum to the distal descending colon. Microscopically, the polyps consist of elongated, tortuous, and distended crypts covered by a “cap” of inflammatory granulation tissue. Although the pathogenesis is unknown, mucosal prolapse has been postulated to be an important etiological factor, given certain clinical and histological similarities. We describe two cases of cap polyposis with protein-losing enteropathy. One was treated successfully by avoidance of straining at defecation. Another resolved after double-barreled transverse colostomy. Both successful treatments support a causal link of polyposis to prolapse.

Modulation of endoplasmic reticulum (ER) stress-induced autophagy by C/EBP homologous protein (CHOP) and inositol-requiring enzyme 1α (IRE1α) in human colon cancer cells.

To explore the relationship between UPR and autophagy in intestinal epithelial cells, we investigated whether autophagy was induced by endoplasmic reticulum (ER) stress in colon cancer cell lines. We demonstrated that autophagy was induced by ER stress in HT29, SW480, and Caco-2 cells. In these cells, inositol-requiring enzyme1α (IRE1α) and C/EBP homologous protein (CHOP) were involved in the ER stress-autophagy pathway, and CHOP was a regulator of IRE1α protein expression. Our findings suggest that CHOP promotes IRE1α and autophagy especially in ER stress conditions. This study will provide important insights into the disclosure of the ER stress-autophagy pathway.