A genome-wide association study identified PTPN2 as a population-specific susceptibility gene locus for primary biliary cholangitis.

BACKGROUND AIMS: Previous genome-wide association studies (GWAS) have indicated the involvement of shared (population-non-specific) and non-shared (population-specific) susceptibility genes in the pathogenesis of primary biliary cholangitis (PBC) among European and East-Asian populations. Although a meta-analysis of these distinct populations has recently identified more than 20 novel PBC susceptibility loci, analyses of population-specific genetic architecture are still needed for a more comprehensive search for genetic factors in PBC. APPROACH RESULTS: Protein tyrosine phosphatase non-receptor type 2 (PTPN2) was identified as a novel PBC susceptibility gene locus through a GWAS and subsequent genome-wide meta-analysis involving 2,181 cases and 2,699 controls from the Japanese population (GWAS-lead variant: rs8098858, p=2.6×10-8). In-silico and in-vitro functional analyses indicated that the risk allele of rs2292758, which is a primary functional variant, decreases PTPN2 expression by disrupting Sp1 binding to the PTPN2 promoter in T follicular helper cells (Tfh) and plasmacytoid dendritic cells (pDCs). Infiltration of PTPN2-positive T-cells and pDCs were confirmed in the portal area of the PBC-liver by immunohistochemistry. Furthermore, transcriptomic analysis of PBC-liver samples indicated the presence of a compromised negative feedback loop in-vivo between PTPN2 and IFNG in patients carrying the risk allele of rs2292758. CONCLUSIONS: PTPN2, a novel susceptibility gene for PBC in the Japanese population, may be involved in the pathogenesis of PBC via an insufficient negative feedback loop caused by the PTPN2 risk allele of rs2292758 in IFN signaling. This suggests that PTPN2 could be a potential molecular target for PBC treatment.

Role of deleterious single nucleotide variants in the coding regions of TNFAIP3 for Japanese autoimmune hepatitis with cirrhosis.

Autoimmune hepatitis (AIH) is an autoimmune liver disease and cirrhosis is sometimes complicated with AIH at diagnosis, influencing its prognosis. TNFAIP3 gene encodes A20, an inhibitor of nuclear factor-κB pathway, and is a susceptibility gene for autoimmune diseases. We investigated deleterious variants in the coding regions of TNFAIP3 gene of Japanese AIH patients or those with cirrhosis. The deleterious variants in the coding regions of TNFAIP3 gene were analyzed by the cycle sequencing method and the frequencies of deleterious TNFAIP3 alleles of AIH or AIH with cirrhosis were compared with those of Japanese controls. The deleterious alleles in TNFAIP3 were not associated with AIH. A significant association was shown for the deleterious alleles in TNFAIP3 (P = 0.0180, odds ratio (OR) 4.28, 95% confidence interval (CI) 1.53-11.95) with AIH with cirrhosis at presentation. The serum IgM levels in AIH patients with deleterious alleles in TNFAIP3 were tended to be lower than those without (P = 0.0152, Q = 0.1216). The frequency of deleterious alleles in TNFAIP3 was higher in the AIH subset without the DRB1 risk alleles than that with (P = 0.0052, OR 5.10, 95%CI 1.55-16.74). The deleterious alleles in TNFAIP3were associated with AIH with cirrhosis.

POGLUT1, the putative effector gene driven by rs2293370 in primary biliary cholangitis susceptibility locus chromosome 3q13.33.

Primary biliary cholangitis (PBC) is a chronic and cholestatic autoimmune liver disease caused by the destruction of intrahepatic small bile ducts. Our previous genome-wide association study (GWAS) identified six susceptibility loci for PBC. Here, in order to further elucidate the genetic architecture of PBC, a GWAS was performed on an additional independent sample set, then a genome-wide meta-analysis with our previous GWAS was performed based on a whole-genome single nucleotide polymorphism (SNP) imputation analysis of a total of 4,045 Japanese individuals (2,060 cases and 1,985 healthy controls). A susceptibility locus on chromosome 3q13.33 (including ARHGAP31, TMEM39A, POGLUT1, TIMMDC1, and CD80) was previously identified both in the European and Chinese populations and was replicated in the Japanese population (OR = 0.7241, P = 3.5 × 10-9). Subsequent in silico and in vitro functional analyses identified rs2293370, previously reported as the top-hit SNP in this locus in the European population, as the primary functional SNP. Moreover, e-QTL analysis indicated that the effector gene of rs2293370 was Protein O-Glucosyltransferase 1 (POGLUT1) (P = 3.4 × 10-8). This is the first study to demonstrate that POGLUT1 and not CD80 is the effector gene regulated by the primary functional SNP rs2293370, and that increased expression of POGLUT1 might be involved in the pathogenesis of PBC.

Lack of association between the CARD10 rs6000782 polymorphism and type 1 autoimmune hepatitis in a Japanese population.

BACKGROUND: Previous genome-wide association studies have evaluated the impact of common genetic variants and identified several non-HLA risk loci associated with autoimmune liver diseases. More recent genome-wide association studies and replication analyses reported an association between variants of the CARD10 polymorphism rs6000782 and risk of type 1 autoimmune hepatitis (AIH). In this case-control study, we genotyped 326 Japanese AIH patients and 214 control subjects. RESULTS: Genomic DNA from 540 individuals of Japanese origin, including 326 patients with type-1 AIH and 214 healthy controls, was analyzed for two single nucleotide polymorphisms (SNPs) in the CARD10 gene. We selected CARD10 rs6000782 SNPs and genotyped these using PCR-RFLP method and direct sequencing. The Chi square test revealed that the rs6000782 variant alle (c) was not associated with the susceptibility for AIH in a Japanese population [p = 0.376, odds ratio (OR) 1.271, 95 % confidence interval (CI) 0.747-2.161] in an allele model. Our data also showed that CARD10 rs6000782 variants were not associated with AIH or with the clinical parameters of AIH. CONCLUSIONS: In this study we examined an association between rs6000782 SNPs in the CARD10 gene and type-1 AIH. Results showed no significant association of rs62000782 with type-1 AIH in a Japanese population. This study demonstrated no association between CARD10 rs6000782 variants and AIH in a Japanese population.

Circulating microRNA Profiles in Patients with Type-1 Autoimmune Hepatitis.

Recent studies have demonstrated that micro (mi)RNA molecules can be detected in the circulation and can serve as potential biomarkers of various diseases. This study used microarray analysis to identify aberrantly expressed circulating miRNAs in patients with type 1 autoimmune hepatitis (AIH) compared with healthy controls. Patients with well-documented and untreated AIH were selected from the National Hospital Organization (NHO)-AIH-liver-network database. They underwent blood sampling and liver biopsy with inflammation grading and fibrosis staging before receiving treatment. To further confirm the microarray data, circulating expression levels of miR-21 and miR-122 were quantified by real-time quantitative polymerase chain reaction in 46 AIH patients, 40 patients with chronic hepatitis C (CHC), and 13 healthy controls. Consistent with the microarray data, serum levels of miR-21 were significantly elevated in AIH patients compared with CHC patients and healthy controls. miR-21 and miR-122 serum levels correlated with alanine aminotransferase levels. Circulating levels of miR-21 and miR-122 were significantly reduced in AIH patients with liver cirrhosis, and were inversely correlated with increased stages of fibrosis. By contrast, levels of circulating miR-21 showed a significant correlation with the histological grades of inflammation in AIH. We postulate that aberrantly expressed serum miRNAs are potential biomarkers of AIH and could be implicated in AIH pathogenesis. Alternations of miR-21 and miR-122 serum levels could reflect their putative roles in the mediation of inflammatory processes in AIH.

Enteral nutrition decreases hospitalization rate in patients with Crohn's disease.

BACKGROUND AND AIMS: Crohn's disease (CD) is a chronic inflammatory bowel disease with relapse and remission. CD patients are admitted to hospital when bowel inflammation flares up severely, which lowers their quality of life. Enteral nutrition (EN) with an elemental diet plays an important role in the treatment for CD patients in Japan, because of its few adverse effects, and it is thought to be effective in maintaining remission. We investigated the effectiveness of EN with an elemental diet with regard to the avoidance of hospitalization. METHODS: A total of 268 patients with CD who visited hospital from 2003-2008 were enrolled. The relationship between the caloric content of an elemental diet and hospitalization as an end-point was examined retrospectively using Cox regression analysis. Cumulative non-hospitalization rates were calculated by the Kaplan-Meier method. RESULTS: Of the 268 patients, 155 received an elemental diet providing 900 kcal/day or more. Among 237 patients with ileal involvement, 135 patients receiving an elemental diet providing 900 kcal/day or more showed a statistically significant improvement in cumulative non-hospitalization rate. Among 31 patients without ileal involvement, in contrast, the cumulative non-hospitalization rate did not differ among those receiving an elemental diet of less or more than 900 kcal/day. CONCLUSION: The use of an elemental diet of 900 kcal/day may be effective in avoiding hospitalization in CD patients with ileal lesions. This diet may be useful in improving the long-term convalescence of these patients.

Relationship between nutritional therapy and surgery in Crohn's disease.

BACKGROUND/AIMS: Crohn's disease is often refractory and some patients require repeated surgical treatment. Nutritional therapy with an elemental diet has been reported effective in improving nutritional state and suppressing inflammation, and might be expected to assist in minimizing the need for surgery. We evaluated the relationship between an elemental diet and the period that patients spent without intestinal resection. METHODOLOGY: A total of 153 patients with Crohn's disease who visited our hospital from July, 1999 to July, 2005 were enrolled. The relationship between the caloric content of an elemental diet and surgery as an endpoint was examined using Cox regression analysis. Cumulative non-operation rates were calculated by the Kaplan-Meier method. Statistical significance was determined using the log-rank test. RESULTS: Among patients with jejunoileal involvement, patients receiving an elemental diet providing 900 kcal or more per day showed a statistically significant improvement in cumulative non-operation rate. Among those without jejunoileal involvement, in contrast, the cumulative non-operation rate did not differ among those receiving an elemental diet of less or more than 900 kcal per day. CONCLUSIONS: The use of an elemental diet of 900 kcal per day may be effective in avoiding surgery in patients with jejunoileal lesions. This diet may be useful in improving long-term convalescence in these patients.

Value of colonoscopy for prediction of prognosis in patients with ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory bowel disorder characterized by exacerbations and remissions. Some UC patients remain refractory to conventional medical treatment while, in others, the effectiveness of drugs is limited by side-effects. Recently, cyclosporine and leukocyte removal therapy have been used for refractory UC patients. To predict the efficacy of these therapies is important for appropriate selection of treatment options and for preparation for colectomy. Endoscopy is the cornerstone for diagnosis and evaluation of UC. Endoscopic parameters in patients with severe or refractory UC may predict a clinical response to therapies, such as cyclosporine or leukocyte removal therapy. As for the patients with quiescent UC, relapse of UC is difficult to predict by routine colonoscopy. Even when routine colonoscopy suggests remission and a normal mucosal appearance, microscopic abnormalities may persist and relapse may occur later. To more accurately identify disease activity and to predict exacerbations in UC patients with clinically inactive disease is important for deciding whether medical treatment should be maintained. Magnifying colonoscopy is useful for the evaluation of disease activity and for predicting relapse in patients with UC.

A case of cytomegalovirus enterocolitis diagnosed by the double-balloon enteroscopy.

A 73-year-old woman presented with massive bloody stools while undergoing hospitalization for multiple myeloma. Colonoscopy and transrectal double-balloon enteroscopy revealed multiple punched-out ulcers throughout the entire colon and in the distal ileum. Cytomegalovirus was detected in the biopsy specimens of both the colonic and ileal mucosa and in the peripheral blood, which lead the diagnosis of CMV enterocolitis. The patient's gastrointestinal bleeding was temporarily improved by the administration of ganciclovir, though she died thereafter due to progression of the primary disease. We herein report the effectiveness of transrectal double-balloon enteroscopy for the diagnosis of cytomegalo-virus enterocolitis.

Magnifying chromoscopy, a novel and useful technique for colonoscopy in ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory bowel disorder characterized by exacerbations and remissions. The degree of inflammation as assessed by conventional colonoscopy is a reliable parameter of disease activity. However, even when conventional colonoscopy suggests remission and normal mucosal findings, microscopic abnormalities may persist, and relapse may occur later. Patients with long-standing, extensive ulcerative colitis have an increased risk of developing colorectal cancer. Ulcerative colitis-associated colorectal cancer is characterized by an early age at onset, poorly differentiated tumor cells, mucinous carcinoma, and multiple lesions. Early detection of dysplasia and colitic cancer is thus a prerequisite for survival. A relatively new method, magnifying chromoscopy, is thought to be useful for the early detection and diagnosis of dysplasia and colitic cancer, as well as the prediction of relapse.