Yoichi Kakuta

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.

Variants in CPA1 are strongly associated with early onset chronic pancreatitis

Chronic pancreatitis is an inflammatory disorder of the pancreas. We analyzed CPA1, encoding carboxypeptidase A1, in subjects with nonalcoholic chronic pancreatitis (cases) and controls in a German discovery set and three replication sets. Functionally impaired variants were present in 29/944 (3.1%) German cases and 5/3,938 (0.1%) controls (odds ratio (OR) = 24.9, P = 1.5 × 10−16). The association was strongest in subjects aged ≤10 years (9.7%; OR = 84.0, P = 4.1 × 10−24). In the replication sets, defective CPA1 variants were present in 8/600 (1.3%) cases and 9/2,432 (0.4%) controls from Europe (P = 0.01), 5/230 (2.2%) cases and 0/264 controls from India (P = 0.02) and 5/247 (2.0%) cases and 0/341 controls from Japan (P = 0.013). The mechanism by which CPA1 variants confer increased pancreatitis risk may involve misfolding-induced endoplasmic reticulum stress rather than elevated trypsin activity, as is seen with other genetic risk factors for this disease.

Association study of TNFSF15 polymorphisms in Japanese patients with inflammatory bowel disease

Tumour necrosis factor superfamily (TNFSF) 15 is a novel member of the TNFSF and its mRNA and protein expression is upregulated in inflammatory bowel disease (IBD), particularly in Crohn’s disease (CD).1,2 Recently, Yamazaki et al performed a large scale case control study using single nucleotide polymorphism (SNP) markers and reported that polymorphisms in TNFSF15 conferred susceptibility to CD in both Japanese and UK populations.3 They also suggested a potential association between a Caucasian ulcerative colitis (UC) cohort and TNFSF15 , but this association was not studied in Japanese patients. To investigate this possible association between TNFSF15 and Japanese UC, and to replicate this association with CD in Japanese, we performed a case control association study in Japanese patients …

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.

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

BACKGROUND Intestinal 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. AIM To elucidate changes of faecal microbiota in Crohns disease patients treated with elemental diet and total parenteral nutrition. METHODS Stool 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. RESULTS In 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. CONCLUSION Faecal 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

AIM To investigate the short and long-term outcomes of endoscopic balloon dilatation (EBD) for Crohns disease (CD) strictures. METHODS Between 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. RESULTS Primary 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). CONCLUSION Anastomotic 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.

Erratum to: FCGR3A-158 polymorphism influences the biological response to infliximab in Crohn’s disease through affecting the ADCC activity

An association between FCGR3A-158 V/F polymorphism and biological responses to infliximab has been reported in Crohn’s disease (CD) in Western countries. However, little is known about the mechanism by which gene polymorphism affects the responses to infliximab. The aims of this study were to confirm the association in Japanese CD patients and to reveal the effect of gene polymorphism on biological responses to infliximab. Japanese CD patients were examined retrospectively at weeks 8 and 30. Clinical and biological responses were assessed by the Crohn’s disease activity index and C-reactive protein levels, respectively. The infliximab-binding affinity of natural killer (NK) cells from FCGR3A-158 V/V, V/F and F/F donors was examined. Infliximab-mediated antibody-dependent cell-mediated cytotoxicity (ADCC) activities were also determined using transmembrane TNF-α-expressing Jurkat T cells as target cells and peripheral blood mononuclear cells (PBMCs) from V/V, V/F and F/F donors as effector cells. Biological responses at week 8 were statistically higher in V/V patients, whereas no significant differences were observed in either clinical responses at weeks 8 and 30 or biological responses at week 30 among the three genotypes. NK cells and PBMCs from V/V patients also showed higher infliximab-binding affinity and infliximab-mediated ADCC activity, respectively. Our results suggest that FCGR3A-158 polymorphism is a predicting factor of biological responses to infliximab in the early phases. FCGR3A-158 polymorphism was also found to affect the infliximab-binding affinity of NK cells and infliximab-mediated ADCC activity in vitro, suggesting that an effect on ADCC activity influences biological responses to infliximab in CD patients.

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.

Life-event stress induced by the Great East Japan Earthquake was associated with relapse in ulcerative colitis but not Crohn's disease: a retrospective cohort study

Objective Stress is thought to be one of the triggers of relapses in patients with inflammatory bowel disease (IBD). We examined the rate of relapse in IBD patients before and after the Great East Japan Earthquake. Design A retrospective cohort study. Settings 13 hospitals in Japan. Participants 546 ulcerative colitis (UC) and 357 Crohns disease (CD) patients who received outpatient and inpatient care at 13 hospitals located in the area that were seriously damaged by the earthquake. Data on patients clinical characteristics, disease activity and deleterious effects of the earthquake were obtained from questionnaires and hospital records. Primary outcome We evaluated the relapse rate (from inactive to active) across two consecutive months before and two consecutive months after the earthquake. In this study, we defined ‘active’ as conditions with a partial Mayo score=2 or more (UC) or a Harvey-Bradshaw index=6 or more (CD). Results Among the UC patients, disease was active in 167 patients and inactive in 379 patients before the earthquake. After the earthquake, the activity scores increased significantly (p<0.0001). A total of 86 patients relapsed (relapse rate=15.8%). The relapse rate was about twice that of the corresponding period in the previous year. Among the CD patients, 86 patients had active disease and 271 had inactive disease before the earthquake. After the earthquake, the activity indices changed little. A total of 25 patients experienced a relapse (relapse rate=7%). The relapse rate did not differ from that of the corresponding period in the previous year. Multivariate analyses revealed that UC, changes in dietary oral intake and anxiety about family finances were associated with the relapse. Conclusions Life-event stress induced by the Great East Japan Earthquake was associated with relapse in UC but not CD.

Identification of novel missense CTRC variants in Japanese patients with chronic pancreatitis

We read with great interest the article by Paliwal et al 1 reporting the identification of novel missense variants in the chymotrypsin C ( CTRC ) gene in patients with tropical pancreatitis and idiopathic chronic pancreatitis (CP) in India. Because there might be geographical differences in the genetics of pancreatitis, we conducted screening of the CTRC gene in Japanese patients with CP. All the eight exons in the CTRC gene were directly sequenced in 506 patients with CP (244 alcoholic, 206 idiopathic, 35 hereditary and 21 familial) and 274 healthy controls as previously described.1 This study was approved by the ethics committee of Tohoku University School of Medicine (article #2012-1-158). We identified five missense variants in patients with CP and one in controls (table 1 …