Immunoglobulin subtype-coated bacteria are correlated with the disease activity of inflammatory bowel disease.

Immune response involving various immunoglobulin (Ig) isotypes and subtypes to microbiome is involved in the pathogenesis and disease activity of inflammatory bowel diseases (IBDs). To clarify the presence of Ig-coated bacteria in the intestine and its association with disease activity in ulcerative colitis (UC) and Crohn's disease (CD), we extracted and classified Ig-coated bacteria from fecal samples of 42 patients with IBD and 12 healthy controls (HCs) using flow cytometry and 16S ribosomal RNA sequence analysis. The percentage of bacteria coated with IgA and IgM was higher in patients with IBD than in HCs, and IgG-coated bacteria were found only in patients with IBD. Moreover, the percentages of bacteria coated with IgG1, IgG2, IgG3, and IgM in UC samples and IgG3, IgG4, and IgM in CD samples were correlated with disease activities. The proportions of Bacteroides ovatus and Streptococcus increased during the active phase of CD. Hence, the detailed analysis of Ig-coated bacteria and Ig subtypes using flow cytometry could aid in developing useful indicators of disease activity and identifying more disease-related bacteria, which could become novel treatment targets for IBDs.

Liquid Biopsy for Colorectal Adenoma: Is the Exosomal miRNA Derived From Organoid a Potential Diagnostic Biomarker?

INTRODUCTION: MicroRNAs (miRNAs) can serve as tumor biomarkers; however, their role in evaluating colorectal adenoma (CRA) is unclear. Recently, the organoid culture system enabled long-term expansion of human colon epithelium. This study aimed to examine the potential of exosomal miRNAs extracted from CRA organoids as biomarkers in the clinical liquid biopsy CRA test. METHODS: We established organoid cultures from normal colon and CRA using resected specimens. Exosomes were isolated from the conditioned medium organoids. MiRNAs were isolated from the exosomes, and their expression profiles were compared using microarray analysis. To identify miRNA candidates for liquid biopsy, we prospectively compared changes in their expression in serum and exosomes before and after endoscopic resection in 26 patients with CRA. RESULTS: Seven exosomal miRNAs were overexpressed in CRA organoids: miR-4323, miR-4284, miR-1268a, miR-1290, miR-6766-3p, miR-21-5p, and miR-1246. The expression levels of 4 exosomal miRNAs (miR-4323, miR-4284, miR-1290, and miR-1246) and 2 serum miRNAs (miR-1290 and miR-1246) were significantly lower in posttreatment sera. The combined expression of 4 exosomal miRNAs could identify both CRA and large-size (>12.6 cm2) CRA with respective areas under the curve of 0.698 (95% confidence interval [CI] = 0.536-0.823) and 0.834 (95% CI = 0.660-0.929). Combinations of 2-serum miRNA expression values could identify both CRA and large-size CRA with respective area under the curves of 0.691 (95% CI = 0.528-0.817) and 0.834 (95% CI = 0.628-0.938). DISCUSSION: We found that exosomal miRNAs derived from the CRA organoid culture could be potential diagnostic biomarkers for CRA.

Localized intestinal AL amyloidosis detected as bright green using autofluorescence endoscopy.

Amyloidosis is classifiable as systemic, with amyloid deposition in organs throughout the body, or localized, involving only one organ. Amyloidosis localized in the intestinal tract is rare. This report describes three cases of localized AL amyloidosis in the intestinal tract and presents their clinical characteristics, endoscopic findings, and prognoses. All three cases were asymptomatic, and were found accidentally during endoscopy for closer examination after a positive fecal occult blood test. Endoscopic findings included patchy redness and meandering dilated vessels of the lesion. Using autofluorescence (AFI) endoscopy, the lesion of amyloid deposition was enhanced as bright green. We used fluorescence microscopy to observe unstained specimens obtained from an amyloid deposition site with excitation light. Autofluorescence was detected with the broad excitation wavelength at amyloid deposition lesion sites of the specimen. Results revealed that AL amyloid has autofluorescence that engenders its detection by AFI endoscopy as bright green. In none of the three cases was systemic amyloidosis or organ failure observed. The long-term course of all the cases was favorable.

Comprehensive Analysis of microRNA Profiles in Organoids Derived from Human Colorectal Adenoma and Cancer.

INTRODUCTION: Exosomes are membrane-enclosed nanovesicles, which are increasingly being recognized as important cell communication components for their role in transmitting microRNAs (miRNAs). No previous study has addressed the exosomal miRNA profile in colorectal adenomas (CRAs) because the long-term culture of CRA is challenging. This study aimed to identify the miRNA signature in organoid exosomes derived from human CRA and colorectal cancer (CRC) samples. METHODS: Organoid cultures were developed from resected colorectal tissues of patients with CRA or CRC undergoing surgery or endoscopic mucosal resection. Exosomes were prepared from the conditioned medium of the organoids. miRNAs were prepared from the exosomes and their source organoids. The miRNA expression profiles were compared using microarray analysis. The impact of alteration of miRNA expression on cell proliferation was examined using miRNA mimics or inhibitors in HT-29 human CRC cells. RESULTS: We established 6 organoid lines from CRC and 8 organoid lines from CRA. Exosomal miRNA signatures were different between the organoids derived from CRA and CRC. Both exosomal and cellular miR-1246 expressions were upregulated in CRC-derived organoids compared to their expression in CRA-derived organoids. Alteration of miR-1246 expression by the miR-1246 mimic or inhibitor increased or decreased cell proliferation in HT-29 cells, respectively. CONCLUSIONS: We report for the first time the miRNA profiles of exosomes in CRA- and CRC-derived organoids. The upregulation of miR-1246 might play a role in increased cell proliferation in the process of CRA-carcinoma transition.

Factors Associated with Fibrosis during Colorectal Endoscopic Submucosal Dissection: Does Pretreatment Biopsy Potentially Elicit Submucosal Fibrosis and Affect Endoscopic Submucosal Dissection Outcomes?

BACKGROUND: Submucosal fibrosis observed during colorectal endoscopic submucosal dissection (ESD) is an important factor related to incomplete resection. Biopsy is generally accepted as having the potential to elicit submucosal fibrosis, but few reports have presented definitive proof. This study investigated the relation between submucosal fibrosis and colorectal ESD outcomes and assessed factors related to fibrosis, including pretreatment biopsy. METHODS: After reviewing 369 records of colorectal ESD performed between January 2011 and December 2016, we assessed the relation between fibrosis and ESD outcomes. Multiple logistic regression analysis revealed fibrosis risk factors. RESULTS: Severe fibrosis was related significantly to ESD outcomes such as the mean procedure time (p < 0.001), en bloc resection rate (p < 0.001), and R0 resection rate (p = 0.011). Multivariate analyses indicated residual lesions (ORs 175.4, p < 0.001), pretreatment biopsy (ORs 8.30, p = 0.002), nongranular-type laterally spreading tumors (LST-NG; ORs 5.86, p = 0.025), and invasive carcinoma (ORs 5.83, p = 0.03) as independent risk factors of severe fibrosis. In each macroscopic type, LST-NG was more strongly related to fibrosis induced by pretreatment than granular-type laterally spreading tumors with adjust ORs of 50.8 and 4.69. CONCLUSIONS: Pretreatment biopsy causes submucosal fibrosis resulting in prolonged procedure times and incomplete resection. These findings suggest important benefits of avoiding biopsy before ESD.

Repertoire analysis of memory T-cell receptors in Japanese patients with inflammatory bowel disease.

BACKGROUND AND AIM: The T-cell receptor (TCR) repertoire was assessed in response to various antigens and was considered to be associated with the pathogenesis of inflammatory bowel disease (IBD). Thus, we performed TCR repertoire analysis to examine the pathology of IBD from changes in the TCR repertoire of memory T cells in the intestinal lamina propria mononuclear cells (LPMCs) and peripheral blood mononuclear cells (PBMCs) of patients with IBD. METHODS: LPMCs in the surgical specimens and PBMCs were isolated from 12 patients with IBD (5 patients with ulcerative colitis [UC] and 7 patients with Crohn's disease [CD]). PBMCs were collected from 10 healthy individuals as controls. Comprehensive TCR sequence analyses of adaptor-ligation polymerase chain reaction (PCR) products were performed using MiSeq. RESULTS: The diversity of TCR-α and TCR-ß in PBMCs was significantly lower in patients with IBD than that in controls (P = 0.00084 and 0.0013, respectively). Comparisons of TCR diversity in LPMCs and PBMCs between CD and UC showed that the diversity in LPMC was not affected by diseases, whereas that in PBMCs was significantly lower in CD than in UC (P = 0.045 and 0.049, respectively). Some TCR clones may have shown a specific increase or decrease in CD and UC, and many clones were common to both LPMCs and PBMCs in the same patients. CONCLUSION: The diversity of TCR clones in LPMCs and PBMCs in patients with IBD was significantly lower than that of PBMCs in controls. TCR diversity in PBMCs was particularly low in patients with CD.

An Integrated Genomic and Transcriptomic Analysis Reveals Candidates of Susceptibility Genes for Crohn's Disease in Japanese Populations.

Expression quantitative trait locus (eQTL) analyses have enabled us to predict the function of disease susceptibility SNPs. However, eQTL for the effector memory T cells (TEM) located in the lamina propria mononuclear cells (LPMCs), which play an important role in Crohn's disease (CD), are not yet available. Thus, we conducted RNA sequencing and eQTL analyses of TEM cells located in the LPMCs from IBD patients (n = 20). Genome-wide association study (GWAS) was performed using genotyping data of 713 Japanese CD patients and 2,063 controls. We compared the results of GWAS and eQTL of TEM, and also performed a transcriptome-wide association study using eQTL from Genotype Tissue Expression project. By eQTL analyses of TEM, correlations of possible candidates were confirmed in 22,632 pairs and 2,463 genes. Among these candidates, 19 SNPs which showed significant correlation with tenascin-XA (TNXA) expression were significantly associated with CD in GWAS. By TWAS, TNFSF15 (FDR = 1.35e-13) in whole blood, ERV3-1 (FDR = 2.18e-2) in lymphocytes, and ZNF713 (FDR = 3.04e-2) in the sigmoid colon was significantly associated with CD. By conducting integration analyses using GWAS and eQTL data, we confirmed multiple gene transcripts are involved in the development of CD.

Long-Term Prognosis of Japanese Patients with Crohn's Disease Treated by Switching Anti-Tumor Necrosis Factor-α Antibodies.

INTRODUCTION: The long-term prognosis of Japanese patients with Crohn's disease (CD) treated by switching anti-tumor necrosis factor-α (anti-TNFα) antibodies remains unclear. OBJECTIVE: This study aimed to clarify the long-term prognosis and clinical factors that affect the long-term prognosis and outcomes of such patients. METHODS: This retrospective, observational, single-center cohort study analyzed Japanese patients with CD treated by switching between infliximab and adalimumab in the Tohoku University Hospital between March 2003 and December 2017. Cumulative relapse-free survival and cumulative surgery-free survival rates were analyzed using the Kaplan-Meier method. Clinical factors that affected the long-term outcomes were identified using both a log-rank test and the Cox proportional hazards model. RESULTS: The cumulative relapse-free survival rates were 68.6, 33.7, and 22.9% at 1, 3, and 5 years, respectively. The surgery-free survival rates were 91.7, 75.7, and 57.4% at 1, 3, and 5 years, respectively. The cumulative relapse-free survival rate was significantly higher in the group with ileal lesions (HR = 0.12; 95% CI 0.0066-0.64, p = 0.0086), stricture (HR = 0.24; 95% CI 0.0094-0.59, p = 0.0021), and a penetrating type (HR = 0.34; 95% CI 0.14-0.84, p = 0.020). Intolerance (HR = 0.29; 95% CI 0.12-0.63, p = 0.0013) and switching after surgery (HR = 0.41; 95% CI 0.17-0.87, p = 0.019) were clinical factors that reduced the risk of recurrence. The cumulative surgery-free survival rate was significantly higher in the group that switched after surgery (HR = 0.28; 95% CI 0.074-0.91, p = 0.034) and used concomitant thiopurine (HR = 0.32; 95% CI 0.10-0.90, p = 0.030). CONCLUSION: We should clarify the reason for switching anti-TNFα antibodies and investigate bowel complications before switching. Surgical reset of bowel complications including stricture and fistula could reduce the risk of recurrence after switching anti-TNFα antibodies. Concomitant thiopurine administration might reduce the risk of bowel surgery after switching anti-TNFα antibodies.

Identification of two major autoantigens negatively regulating endothelial activation in Takayasu arteritis.

The presence of antiendothelial cell antibodies (AECAs) has been documented in Takayasu arteritis (TAK), a chronic granulomatous vasculitis. Here, we identify cell-surface autoantigens using an expression cloning system. A cDNA library of endothelial cells is retrovirally transfected into a rat myeloma cell line from which AECA-positive clones are sorted with flow cytometry. Four distinct AECA-positive clones are isolated, and endothelial protein C receptor (EPCR) and scavenger receptor class B type 1 (SR-BI) are identified as endothelial autoantigens. Autoantibodies against EPCR and SR-BI are detected in 34.6% and 36.5% of cases, respectively, with minimal overlap (3.8%). Autoantibodies against EPCR are also detected in ulcerative colitis, the frequent comorbidity of TAK. In mechanistic studies, EPCR and SR-BI function as negative regulators of endothelial activation. EPCR has also an effect on human T cells and impair Th17 differentiation. Autoantibodies against EPCR and SR-BI block the functions of their targets, thereby promoting pro-inflammatory phenotype.

Genetic Analysis of Ulcerative Colitis in Japanese Individuals Using Population-specific SNP Array.

BACKGROUND: To clarify the genetic background of ulcerative colitis (UC) in the Japanese population, we conducted a genome-wide association study (GWAS) using a population-specific single nucleotide polymorphism (SNP) array. METHODS: We performed a GWAS and replication study including 1676 UC patients and 2381 healthy controls. The probability of colectomy was compared between genotypes of rs117506082, the top hit SNP at HLA loci, by the Kaplan-Meier method. We studied serum expression of miR-622, a newly identified candidate gene, from 32 UC patients and 8 healthy controls by quantitative reverse-transcription polymerase chain reaction. RESULTS: In the GWAS, only the HLA loci showed genome-wide significant associations with UC (rs117506082, P = 6.69E-28). Seven nominally significant regions included 2 known loci, IL23R (rs76418789, P = 6.29E-7) and IRF8 (rs16940202, P = 1.03E-6), and 5 novel loci: MIR622 (rs9560575, P = 8.23E-7), 14q31 (rs117618617, P = 1.53E-6), KAT6B (rs12260609, P = 1.81E-6), PAX3-CCDC140-SGPP2 (rs7589797, P = 2.87E-6), and KCNA2 (rs118020656, P = 4.01E-6). Combined analysis revealed that IL23R p.G149R (rs76418789, P = 9.03E-11; odds ratio [OR], 0.51) had genome-wide significant association with UC. Patients with GG genotype of rs117506082 had a significantly lower probability of total colectomy than those with the GA+AA genotype (P = 1.72E-2). Serum expression of miR-622 in patients with inactive UC tended to be higher than in healthy controls and patients with active UC (inactive UC vs healthy controls, P = 3.03E-02; inactive UC vs active UC, P = 6.44E-02). CONCLUSIONS: IL23R p.G149R is a susceptibility locus for UC in Japanese individuals. The GG genotype of rs117506082 at HLA loci may predict a better clinical course.

Endoscopic radial incision and cutting for Crohn's Disease-associated intestinal stricture: a pilot study.

Background and study aims Intestinal stricture associated with Crohn's disease (CD) is usually treated by endoscopic balloon dilation (EBD) or stricture plasty. Although EBD is effective and safe for such strictures, refractory stricture after EBD poses a problem. Hence, other novel approaches for these refractory strictures are required. On the other hand, the efficacy of radial incision and cutting (RIC) method for esophageal stricture after esophagogastric surgery is reported. In this pilot study, we adopted the RIC technique for five CD patients with refractory intestinal stricture to dilate their strictures. We conducted the RIC procedure using an electric needle knife with a ceramic tip on the top of the needle. Four cases were of anastomotic stricture after ileocecal resection and the remaining one case was of stricture due to mucosal healing. The RIC procedure was successful for all five patients. Average procedure time was 18.6 minutes. One patient developed delayed bleeding after RIC. There were no cases of perforation. RIC could be an alternative therapy for intestinal stricture associated with CD. Further studies should be conducted to clarify its efficacy and safety.

Serum C-reactive protein and albumin are useful biomarkers for tight control management of Crohn's disease in Japan.

Tight control management of Crohn's disease (CD) based on biomarkers is more effective than conventional clinical management; however, fecal calprotectin is not allowed in Asian and some Western countries. To investigate whether tight control management based on readily available serum biomarkers results in better outcomes, we retrospectively reviewed treatment courses of consecutive Japanese CD patients treated with anti-tumor necrosis factor agents between 2003 and 2018. The association between failure of tight control (C-reactive protein (CRP) ≥ 0.5 mg/dL or albumin (Alb) < 3.8 g/dL at week 8 or 24) and subsequent major adverse outcomes (MAOs; hospitalization related to CD worsening, surgery, and discontinuation due to treatment failure) were analyzed. Among 223 patients followed for >8 weeks, 88 patients experienced MAOs. Multivariate analysis identified penetrating type, CRP ≥ 0.5 mg/dL and Alb < 3.8 g/dL at week 8 as independent risk factors (hazard ratios: 2.16, 2.06, and 2.08, respectively). Among 204 patients followed for >24 weeks, 80 patients experienced MAOs. Penetrating type, CRP ≥ 0.5 mg/dL, and Alb < 3.8 g/dL at week 24 were identified as independent risk factors (2.39, 1.90, and 2.20, respectively). Even in settings without fecal calprotectin, tight control management based on serum CRP and Alb may help avoid MAOs.

High-resolution melt analysis enables simple genotyping of complicated polymorphisms of codon 18 rendering the NUDT15 diplotype.

BACKGROUND: The genetic variants of NUDT15 have been verified to induce adverse events (AEs) of thiopurines. Codon 139 variants are frequently observed in Asians, while multiple variants are seen in codon 18 which also cause AEs including the European ancestry. The purpose of this study is to establish a technique capable of the simple genotyping of NUDT15 codon 18 and to evaluate its efficacy. METHODS: A high-resolution melt (HRM) technique is performed to simply determine genotypes. The accuracy of HRM analysis was evaluated with DNAs from 1245 Japanese patients with inflammatory bowel diseases. Subsequently, another group of 572 patients was analyzed to verify the method. The diplotypes and the frequency of their AEs were estimated on the basis of codon 18 and 139 genotypes. RESULTS: The HRM analysis enabled the correct identification of the three main genotypes, ref/ref, ref/ins, and ref/V18I, in 1236 of 1241 cases. All rare genotypes including ref/del were identified as the impossible-to-determine group, the proper diagnosis rate was 99.6%. In the verification test using other samples, the diagnosis rate was 99.7%. By estimating diplotypes using both codon 18 and 139 genotypes, 2.74% and 2.13% of Japanese patients with Arg/Arg and Arg/Cys of codon 139 have a lower enzymatic activity of NUDT15 and a higher risk for adverse responses than those estimated by codon 139 genotypes alone. CONCLUSIONS: Our study showed that HRM method enables simple genotyping of complicated codon 18 variants essential to haplotype estimation of the NUDT15.

Correction to: High-resolution melt analysis enables simple genotyping of complicated polymorphisms of codon 18 rendering the NUDT15 diplotype.

The correct name of the last author should be.

Ustekinumab treatment for hidradenitis suppurativa.

Hidradenitis suppurativa (HS) is a follicular occlusive inflammatory skin disease that occurs in the axilla, groin, buttocks and vulval region. Control of the intractable inflammation is a primary goal of HS treatments. Benefit of anti-tumor necrosis factor (TNF) antibodies against HS have been reported, and adalimumab has been approved for HS in Europe, the USA and Japan. However, the alternative therapies for anti-TNF antibodies have not been established yet. We experienced a case of HS which developed during the infliximab treatment for Crohn's disease (CD) and was well managed by ustekinumab (UST). We reviewed the articles relating to ustekinumab treatments for HS. Twenty-four HS patients, 16 women and eight men, have been treated with ustekinumab. The average age was 35.7 ± 10.8 years (mean ± SD). All were of Hurley stage II or III. Ten (10/24, 41.6%) had received anti-TNF drugs including infliximab, adalimumab and etanercept prior to UST treatment for HS. Although the initial doses varied from 45 mg s.c. to 390 mg i.v., all cases were treated with 45 or 90 mg s.c. every 8 or 12 weeks at the regular dose, by following the regimen for psoriasis or CD. HS in most of the cases started to improve after 3-5 months of UST initiation, and some achieved complete remission. To our knowledge, our case is the first Asian HS patient improved by UST. Overall, UST is useful for HS and could be an alternative treatment if HS patients do not respond to other medications including anti-TNF drugs.

The indole compound MA-35 attenuates tumorigenesis in an inflammation-induced colon cancer model.

In inflammatory bowel disease, chronic inflammation results in the development of colon cancer known as colitis-associated cancer. This disease is associated with tumor necrosis factor-α (TNF-α) signaling. In addition, intestinal fibrosis is a common clinical complication that is promoted by transforming growth factor ß1 (TGF-ß1). In our previous study, MA-35 attenuated renal fibrosis by inhibiting both TNF-α and TGF-ß1 signaling. This study aimed to identify the possible antitumor effects and antifibrotic effects of MA-35 using an AOM/DSS mouse model. MA-35 was orally administered every day for 70 days in the AOM/DSS mouse model. There was no difference in weight loss between the AOM/DSS group and the AOMDSS + MA-35 group, but the disease activity index score and the survival rate were improved by MA-35. MA-35 blocked the anemia and shortening of the colon induced by AOM/DSS. MA-35 reduced the macroscopic formation of tumors in the colon. In the microscopic evaluation, MA-35 reduced inflammation and fibrosis in areas with dysplasia. Furthermore, the TNF-α mRNA level in the colon tended to be reduced, and the interleukin 6, TGF-ß1 and fibronectin 1 mRNA levels in the colon were significantly reduced by MA-35. These results suggested that MA-35 inhibited AOM/DSS-induced carcinogenesis by reducing inflammation and fibrosis.

Correction: Allele-specific DNA methylation of disease susceptibility genes in Japanese patients with inflammatory bowel disease.

[This corrects the article DOI: 10.1371/journal.pone.0194036.].

A Genome-wide Association Study Identifying RAP1A as a Novel Susceptibility Gene for Crohn's Disease in Japanese Individuals.

BACKGROUND AND AIMS: Genome-wide association studies [GWASs] of European populations have identified numerous susceptibility loci for Crohn's disease [CD]. Susceptibility genes differ by ethnicity, however, so GWASs specific for Asian populations are required. This study aimed to clarify the Japanese-specific genetic background for CD by a GWAS using the Japonica array [JPA] and subsequent imputation with the 1KJPN reference panel. METHODS: Two independent Japanese case/control sets (Tohoku region [379 CD patients, 1621 controls] and Kyushu region [334 CD patients, 462 controls]) were included. GWASs were performed separately for each population, followed by a meta-analysis. Two additional replication sets [254 + 516 CD patients and 287 + 565 controls] were analysed for top hit single nucleotide polymorphisms [SNPs] from novel genomic regions. RESULTS: Genotype data of 4 335 144 SNPs from 713 Japanese CD patients and 2083 controls were analysed. SNPs located in TNFSF15 (rs78898421, Pmeta = 2.59 × 10-26, odds ratio [OR] = 2.10), HLA-DQB1 [rs184950714, pmeta = 3.56 × 10-19, OR = 2.05], ZNF365, and 4p14 loci were significantly associated with CD in Japanese individuals. Replication analyses were performed for four novel candidate loci [p <1 × 10-6], and rs488200 located upstream of RAP1A was significantly associated with CD [pcombined = 4.36 × 10-8, OR = 1.31]. Transcriptome analysis of CD4+ effector memory T cells from lamina propria mononuclear cells of CD patients revealed a significant association of rs488200 with RAP1A expression. CONCLUSIONS: RAP1A is a novel susceptibility locus for CD in the Japanese population.

Long-term prognosis of Japanese patients with biologic-naïve Crohn's disease treated with anti-tumor necrosis factor-α antibodies.

BACKGROUND/AIMS: Few reports have described the long-term treatment outcomes of the anti-tumor necrosis factor-α antibody for Japanese Crohn's disease (CD) patients. The aim of this study was to evaluate them and clarify the clinical factors that affect the long-term prognosis of the anti-tumor necrosis factor-α treatments. METHODS: This was a retrospective, observational, single-center cohort study. Japanese CD patients treated with either infliximab or adalimumab as a first-line therapy were analyzed. The cumulative retention rates of the biologics, relapse-free survival, and surgery-free survival were analyzed using Kaplan-Meier methods. The clinical factors associated with the long-term outcomes were estimated by both the log-rank test and Cox proportional hazard model. RESULTS: The cumulative retention rate was significantly higher in the group with a concomitant elemental diet of ≥900 kcal/day, baseline C-reactive protein (CRP) levels <2.6 mg/dL, and baseline serum albumin levels ≥3.5 g/dL, respectively. The baseline serum albumin levels were also associated with both relapse-free and surgery-free survival. The lack of concomitant use of an elemental diet ≥900 kcal/day was identified as the only independent risk factor for the withdrawal of the biologics. CONCLUSIONS: Baseline CRP levels and serum albumin levels could affect the long-term outcomes in CD patients. Concomitant elemental diet of ≥900 kcal/day could have a positive influence on clinical treatment course.

Inflammation-independent TL1A-mediated intestinal fibrosis is dependent on the gut microbiome.

Tumor necrosis factor-like cytokine 1A (TL1A, TNFSF15) is implicated in inflammatory bowel disease (IBD), modulating the location and severity of intestinal inflammation and fibrosis. TL1A expression is increased in inflamed gut mucosa and associated with fibrostenosing Crohn's disease. Tl1a-overexpression in mice lead to spontaneous ileitis, and exacerbated induced proximal colitis and fibrosis. IBD is associated with shifts in the gut microbiome, but the effect of differing microbial populations and their interaction with TL1A on fibrosis has not been investigated. We demonstrate that the pro-fibrotic and inflammatory phenotype resulting from Tl1a-overexpression is abrogated in the absence of resident microbiota. To evaluate if this is due to the absence of a unique bacterial population, as opposed to any bacteria per se, we gavaged germ-free (GF) wild-type and Tl1a-transgenic (Tl1a-Tg) mice with stool from specific pathogen free (SPF) mice and a healthy human donor (Hu). Reconstitution with SPF, but not Hu microbiota, resulted in increased intestinal collagen deposition and fibroblast activation in Tl1a-Tg mice. Notably, there was reduced fibroblast migration and activation under GF conditions compared to native conditions. We then identified several candidate organisms that correlated directly with increased fibrosis in reconstituted mice and showed that these organisms directly impact fibroblast function in vitro. Thus, Tl1a-mediated intestinal fibrosis and fibroblast activation are dependent on specific microbial populations.