A case of IgG4-related disease associated with ulcerative colitis that was successfully treated with a JAK inhibitor.

Glucocorticoids (GC) are the standard of care for the induction and maintenance of remission in immunoglobulin G4 (IgG4)-related diseases. However, IgG4-related diseases often relapse with GC dose reduction, not only making GC dose reduction difficult but also necessitating GC dose escalation in many cases. Therefore, other immunosuppressive drugs are required to maintain remission. Here, we report a 39-year-old man with ulcerative colitis and IgG4-related disease who experienced a relapse of both diseases despite treatment with tacrolimus and 6-mercaptopurine. Following the initiation of tofacitinib, a Janus-associated kinase inhibitor, it was possible to reduce the GC dose while maintaining remission of both diseases. This case highlights the potential utility of Janus-associated kinase inhibitors in managing complex cases of IgG4-related disease, especially those with concurrent conditions such as ulcerative colitis.

Efficacy and safety of filgotinib for ulcerative colitis: A real-world multicenter retrospective study in Japan.

BACKGROUND AND AIMS: While filgotinib, an oral Janus kinase (JAK) 1 preferential inhibitor, is approved for moderately to severely active ulcerative colitis (UC), real-world studies assessing its short- and long-term efficacy and safety are limited. METHODS: This is a multicenter, retrospective study of UC patients who started filgotinib between March 2022 and September 2023. The primary outcome was clinical remission, defined as a partial Mayo score ≤1 with a rectal bleeding score of 0, or Simple Clinical Colitis Activity Index (SCCAI) ≤2 with a blood-in-stool score of 0. Secondary outcomes included clinical response, corticosteroid-free remission, and endoscopic improvement. Outcomes were assessed at 10, 26, and 58 weeks based on patients with available follow-up. Adverse events were evaluated. RESULTS: We identified 238 UC patients and 54% had prior exposure to biologics/JAK inhibitors. The median baseline partial Mayo score and SCCAI were 5 (IQR 3-6) and 4 (IQR 2-7). Clinical remission rates based on per-protocol analysis at 10, 26, and 58 weeks were 47% (70/149), 55.8% (48/86), and 64.6% (31/48), respectively. At a median follow-up of 28 weeks (IQR 10-54) with a discontinuation rate of 39%, the rates of clinical remission, clinical response, corticosteroid-free remission, and endoscopic improvement were 39.9% (81/203), 54.7% (111/203), and 36.5% (74/203), and 43.5% (10/23), respectively. These rates were comparable between biologic/JAK inhibitor-naïve and -experienced patients. While three patients (1.3%) developed herpes zoster infection, no cases of thrombosis or death were reported. CONCLUSIONS: Real-world data demonstrate favourable clinical and safety outcomes of filgotinib for UC.

Combination of leucine-rich alpha-2 glycoprotein and fecal markers detect Crohn's disease activity confirmed by balloon-assisted enteroscopy.

BACKGROUND/AIMS: Endoscopic activity confirmed by enteroscopy is associated with poor clinical outcome in Crohn's disease (CD). We investigated which of the existing biomarkers best reflects endoscopic activity in CD patients including the small bowel, and whether their combined use can improve accuracy. METHODS: One hundred and four consecutive patients with ileal and ileocolonic type CD who underwent balloon-assisted enteroscopy (BAE) from October 2021 to August 2022 were enrolled, with clinical and laboratory data prospectively collected and analyzed. RESULTS: Hemoglobin, platelet count, C-reactive protein, leucine-rich alpha-2 glycoprotein (LRG), fecal calprotectin, and fecal hemoglobin all showed significant difference in those with ulcers found on BAE. LRG and fecal calprotectin showed the highest areas under the curve (0.841 and 0.853) for detecting ulcers. LRG showed a sensitivity of 78% and specificity of 80% at a cutoff value of 13 µg/mL, whereas fecal calprotectin showed a sensitivity of 91% and specificity of 67% at a cutoff value of 151 µg/g. Dual positivity for LRG and fecal calprotectin, as well as LRG and fecal hemoglobin, both predicted ulcers with an improved specificity of 92% and 100%. A positive LRG or fecal calprotectin/hemoglobin showed an improved sensitivity of 96% and 91%. Positivity for LRG and either of the fecal biomarkers was associated with increased risk of hospitalization, surgery, and relapse. CONCLUSIONS: The biomarkers LRG, fecal calprotectin, and fecal hemoglobin can serve as noninvasive and accurate tools for assessing activity in CD patients confirmed by BAE, especially when used in combination.

Organoids transplantation as a new modality to design epithelial signature to create a membrane-protective sulfomucin-enriched segment.

BACKGROUND: The organoids therapy for ulcerative colitis (UC) is under development. It is important to dissect how the engrafted epithelium can provide benefits for overcoming the vulnerability to inflammation. We mainly focused on the deliverability of sulfomucin, which is reported to play an important role in epithelial function. METHODS: We analyzed each segment of colon epithelium to determine differences in sulfomucin production in both mice and human. Subsequently, we transplanted organoids established from sulfomucin-enriched region into the injured recipient epithelium following dextran sulfate sodium-induced colitis and analyzed the engrafted epithelium in mouse model. RESULTS: In human normal colon, sulfomucin production was increased in proximal colon, whereas it was decreased in the inflammatory region of UC. In murine colon epithelium, increased sulfomucin production was found in cecum compared to distal small intestine and proximal colon. RNA sequencing analysis revealed that several key genes associated with sulfomucin production such as Papss2 and Slc26a1 were enriched in isolated murine cecum crypts. Then we established murine cecum organoids and transplanted them into the injured epithelium of distal colon. Although the expression of sulfomucin was temporally decreased in cecum organoids, its secretion was restored again in the engrafted patches after transplantation. Finally, we verified a part of mechanisms controlling sulfomucin production in human samples. CONCLUSION: This study illustrated the deliverability of sulfomucin in the disease-relevant grafting model to design sulfomucin-producing epithelial units in severely injured distal colon. The current study is the basis for the better promotion of organoids transplantation therapy for refractory UC.

Transmural Remission Characterized by High Biologic Concentrations Demonstrates Better Prognosis in Crohn's Disease.

BACKGROUND: The importance and pathophysiology of transmural healing in patients with Crohn's disease [CD] remains to be verified. We aimed to examine the association between serum concentrations of biologics and transmural remission evaluated via magnetic resonance enterography [MRE]. METHODS: We enrolled patients with CD who received maintenance biologics 1 year after induction and prospectively followed up for at least 1 year after baseline laboratory, endoscopic and MRE examination. We evaluated the relationship between baseline factors including the presence of transmural remission and patient prognosis, as well as between serum concentrations and transmural remission. RESULTS: We included 134 patients, of whom 65, 31, 27 and 11 received infliximab, adalimumab, ustekinumab and vedolizumab, respectively. Those who achieved transmural remission showed a lower risk of hospitalization and surgery than those who did not achieve remission [p < 0.01]. Adjusted hazard ratios of transmural remission for predicting hospitalization and surgery were 0.11 and 0.02, respectively, which were lower than those of clinical remission, biochemical remission and endoscopic remission. Regarding serum concentrations, the median concentration was higher in patients with transmural remission than in patients with transmural activity for all agents [p < 0.01 for infliximab, p = 0.04 for adalimumab, p < 0.01 for ustekinumab, p = 0.08 for vedolizumab]. CONCLUSIONS: Transmural remission was the best predictor for prognosis in CD patients who received maintenance biologic therapy. High drug concentration levels were associated with transmural remission confirmed via MRE.

Hemorrhagic gastric ulcer in a patient with Behcet's disease successfully treated with infliximab.

Behcet's disease (BD) is a multisystem immune-mediated inflammatory disorder that occasionally involves the gastrointestinal tract. Reports on gastrointestinal involvement of BD are relatively rare, of which gastroduodenal involvement is particularly rare. Endoscopic features of gastroduodenal lesions are unknown, and treatment strategies have not been established. In this report, we present the case of a 72-year-old female with gastrointestinal BD who presented with extensive gastroduodenal ulcers and hematemesis that were resistant to colchicine and corticosteroid treatment, which were subsequently successfully treated with infliximab. We also review the current literature on the gastroduodenal involvement of BD. Although rare, the case highlights the importance of being aware of upper gastrointestinal manifestations of BD, as well as demonstrating the potential of infliximab to treat corticosteroid-resistant cases.

Serum Leucine-Rich α2 Glycoprotein: A Novel Biomarker for Transmural Inflammation in Crohn's Disease.

INTRODUCTION: Leucine-rich alpha-2 glycoprotein (LRG) is a newly studied biomarker for inflammatory diseases. This study aimed to investigate whether LRG can be used for evaluating transmural activity in patients with Crohn's disease (CD). METHODS: We performed magnetic resonance enterography (MRE) in 227 consecutive patients with CD from June 2020 to August 2021. We prospectively compared MRE findings with clinical and laboratory data including LRG. MRE was evaluated using 2 validated scoring systems, and transmural inflammation was defined as having a maximum simplified magnetic resonance index of activity (sMaRIA) score of ≥4 and a 5-point classification score of ≥9, respectively. RESULTS: The correlation between LRG and the total MRE score showed a positive correlation ( r = 0.576 for the sMaRIA score, P < 0.01, and r = 0.633 for the 5-point score, P < 0.01). Serum concentrations of LRG significantly increased as MRE scores increased ( P < 0.01). The area under the curve of LRG for a sMaRIA score of ≥4 and a 5-point score of ≥9 was 0.845 and 0.869, respectively, which was significantly higher than that of CDAI ( P < 0.01) or C-reactive protein ( P < 0.01). LRG levels of ≥14 µg/mL had a 67% sensitivity and 90% specificity for a sMaRIA score of ≥4 and a 73% sensitivity and 89% specificity for a 5-point score of ≥9. Patients with high LRG levels were also strongly associated with CD-related hospitalization, surgery, and clinical relapse compared with those with low LRG levels ( P < 0.01 for all). DISCUSSION: LRG is a highly accurate serum biomarker for detecting transmural activity in patients with CD. Results need to be validated in further multicenter studies.

Development and Application of Regenerative Medicine in Inflammatory Bowel Disease.

BACKGROUND: Inflammatory bowel disease (IBD) is characterized by idiopathic and chronic inflammation arising elsewhere within the gastrointestinal tract. Consequently, the mucosal tissue is destroyed during the active phase of the disease, and therefore, spontaneous repair of damaged tissue is required to restore the function and long-term homeostasis of the intestinal mucosa. Also, in patients with refractory Crohn's disease, loss of massive intestinal function can lead to short bowel syndrome or may lead to fatal intestinal failure. SUMMARY: The concept of mucosal healing shares the idea that both regulation of mucosal inflammation and repair of the damaged mucosa are critical to achieve the ideal clinical outcome in patients with IBD. However, current treatments lack the option of those targeted to mucosal repair, and therefore, patients must achieve mucosal healing depending on their intrinsic system. To counteract inflammation-induced mucosal damage, various biologics or cell-based treatments are currently being developed. In the early developmental phase, various growth factors have been tested for their ability to promote mucosal repair. However, most of these factors did not show clinical benefit, except the recombinant glucagon-like peptide-2 (GLP-2). On the contrary, cell-based treatments are rapidly emerging, using both somatic stem cells and pluripotent stem cells. KEY MESSAGES: In this review, we focus on the current state of factor-based or cell-based regenerative medicine in the treatment of IBD. Additionally, we would like to introduce current examples of tissue engineering technologies and provide future prospects for the application of regenerative medicine in IBD.

A case of venous stasis colitis possibly caused by eplerenone.

A 50-year-old man was referred to our hospital for colitis with abdominal pain and diarrhea that had persisted for more than 8 months. 9 months earlier, he had been treated for fulminant eosinophilic myocarditis. During steroid therapy, ulceration appeared in the esophagus, stomach and large intestine. The biopsy results showed cytomegalovirus (CMV) inclusion bodies, and the patient was diagnosed with CMV gastrocolitis and treated with ganciclovir. Colonoscopy 7 months earlier revealed ischemia-like segmental colitis 10 cm in length in the hepatic flexure without evidence of CMV infection. Colonoscopy after 1 month and 3 months showed no improvement. We suspected drug-induced focal ischemic colitis, and discontinued eplerenone. Colonoscopy 2 months after withdrawal of eplerenone showed improvement in colitis, and colonoscopy 8 months later showed ulcer healing. Venous disorders are cautioned as a known side effect of eplerenone, but this is the first report of venous stasis colitis thought to be caused by eplerenone.

Collagen type I-mediated mechanotransduction controls epithelial cell fate conversion during intestinal inflammation.

BACKGROUND: The emerging concepts of fetal-like reprogramming following tissue injury have been well recognized as an important cue for resolving regenerative mechanisms of intestinal epithelium during inflammation. We previously revealed that the remodeling of mesenchyme with collagen fibril induces YAP/TAZ-dependent fate conversion of intestinal/colonic epithelial cells covering the wound bed towards fetal-like progenitors. To fully elucidate the mechanisms underlying the link between extracellular matrix (ECM) remodeling of mesenchyme and fetal-like reprogramming of epithelial cells, it is critical to understand how collagen type I influence the phenotype of epithelial cells. In this study, we utilize collagen sphere, which is the epithelial organoids cultured in purified collagen type I, to understand the mechanisms of the inflammatory associated reprogramming. Resolving the entire landscape of regulatory networks of the collagen sphere is useful to dissect the reprogrammed signature of the intestinal epithelium. METHODS: We performed microarray, RNA-seq, and ATAC-seq analyses of the murine collagen sphere in comparison with Matrigel organoid and fetal enterosphere (FEnS). We subsequently cultured human colon epithelium in collagen type I and performed RNA-seq analysis. The enriched genes were validated by gene expression comparison between published gene sets and immunofluorescence in pathological specimens of ulcerative colitis (UC). RESULTS: The murine collagen sphere was confirmed to have inflammatory and regenerative signatures from RNA-seq analysis. ATAC-seq analysis confirmed that the YAP/TAZ-TEAD axis plays a central role in the induction of the distinctive signature. Among them, TAZ has implied its relevant role in the process of reprogramming and the ATAC-based motif analysis demonstrated not only Tead proteins, but also Fra1 and Runx2, which are highly enriched in the collagen sphere. Additionally, the human collagen sphere also showed a highly significant enrichment of both inflammatory and fetal-like signatures. Immunofluorescence staining confirmed that the representative genes in the human collagen sphere were highly expressed in the inflammatory region of ulcerative colitis. CONCLUSIONS: Collagen type I showed a significant influence in the acquisition of the reprogrammed inflammatory signature in both mice and humans. Dissection of the cell fate conversion and its mechanisms shown in this study can enhance our understanding of how the epithelial signature of inflammation is influenced by the ECM niche.

Mucosal healing of small intestinal stricture is associated with improved prognosis post-dilation in Crohn's disease.

BACKGROUND: Small intestinal stricture is a major cause for surgery in Crohn's disease (CD). Endoscopic balloon dilation (EBD) is performed for small intestinal strictures to avoid surgery, often repeatedly. However, factors that are associated with prognosis after EBD of small intestinal strictures remain poorly investigated. Mucosal healing is the therapeutic target in CD. We aimed to investigate the impact of mucosal healing defined by the presence of ulcers at the small intestinal stricture site on the prognosis of EBD in CD patients. METHODS: We retrospectively included patients with CD who underwent initial EBD for endoscopically impassable small intestinal strictures from January 2012 to March 2020 at a single center. The association between presence of ulcer at the stricture site and surgery after EBD was examined by Cox proportional hazards model. RESULTS: Of the 98 patients included, 63 (64.3%) had ulcer at the stricture site. 20 (31.7%) of these patients underwent surgery for the stricture in due course, whereas 4 (11.4%) of the patients without ulcer of the stricture underwent surgery. In multivariate analysis, patients with ulcer of the stricture had a significantly higher risk for surgery than those without ulcer (hazard ratio 4.84; 95% confidence interval 1.58-14.79). CONCLUSION: Mucosal healing at the stricture site indicated a favorable prognosis after EBD for small intestinal strictures in CD.

Deep neural network for video colonoscopy of ulcerative colitis: a cross-sectional study.

BACKGROUND: A combination of endoscopic and histological evaluation is important in the management of patients with ulcerative colitis. We aimed to adapt our previous deep neural network system (deep neural ulcerative colitis [DNUC]) to full video colonoscopy and evaluate its validity in the real-time detection of histological mucosal inflammation. METHODS: In this multicentre, cross-sectional study, we prospectively enrolled consecutive patients (≥15 years) with ulcerative colitis who had an indication for colonoscopy at five hospitals in Japan. Patients in clinical remission were randomly assigned (1:2) to study 1 and study 2. Those with clinically active disease were assigned to study 2 only. Study 1 assessed the validity of real-time histological assessment using DNUC and study 2 validated the consistency of endoscopic scoring between DNUC and experts. The primary endpoint for study 1 was comparison of the results judged by DNUC (healing or active) with biopsy specimens evaluated by pathologists. In study 2, the primary endpoint was the ability of DNUC to determine the Ulcerative Colitis Endoscopic Index of Severity score compared with centrally evaluated scoring by inflammatory bowel disease endoscopy experts. FINDINGS: From April 1, 2020, to March 31, 2021, 770 patients (180 in study 1 and 590 in study 2) were enrolled. Using real-time histological evaluation, DNUC was able to evaluate the presence or absence of histological inflammation in 729 (81%) of 900 biopsy specimens. For predicting histological remission, the DNUC had a sensitivity of 97·9% (95% CI 97·0-98·5) and a specificity of 94·6% (91·1-96·9). Moreover, its positive predictive value was 98·6% (97·7-99·2) and negative predictive value was 92·1% (88·7-94·3). The intraclass correlation coefficient between DNUC and experts for endoscopic scoring was 0·927 (95% CI 0·915-0·938). INTERPRETATION: DNUC provided consistently accurate endoscopic scoring and showed potential for reducing the number of biopsies required. This system is an objective and consistent application for video colonoscopy that has potential for use in various medical situations. FUNDING: Tokyo Medical and Dental University and Sony.

Intravenous tacrolimus is a superior induction therapy for acute severe ulcerative colitis compared to oral tacrolimus.

BACKGROUND: Intravenous corticosteroid is the mainstay for managing acute severe ulcerative colitis, but one-third of patients do not respond to intravenous corticosteroid. Tacrolimus, a salvage therapy before colectomy, is usually orally administered, though its bioavailability is low compared intravenous administration. The efficacy of intravenous tacrolimus has not been widely studied. AIM: To determine the efficacy and safety of intravenous tacrolimus for the treatment of acute severe ulcerative colitis. METHODS: Eighty-seven hospitalized acute severe ulcerative colitis patients were enrolled for a prospective cohort study between 2009 and 2017. Sixty-five patients received intravenous tacrolimus and 22 received oral tacrolimus. The primary outcome was the achievement of clinical remission within 2 weeks. Relapse and colectomy incidence and adverse events were assessed at 24 weeks. RESULTS: Response rates of both treatments exceeded 50% but were not significantly different. The remission rate was higher in intravenous tacrolimus compared with oral tacrolimus. At 24 weeks, oral and intravenous tacrolimus showed similar relapse-free survival rates; however, colectomy-free survival rates were higher in intravenous tacrolimus compared with oral tacrolimus. CONCLUSIONS: Patients receiving intravenous tacrolimus achieved superior remission and colectomy-free survival rates compared with patients receiving oral tacrolimus. Safety was similar between the two treatments.

Higher concentrations of cytokine blockers are needed to obtain small bowel mucosal healing during maintenance therapy in Crohn's disease.

BACKGROUND: Several studies have reported a positive correlation between serum drug concentrations and endoscopic remission in patients with Crohn's disease. AIM: To examine the association between the concentrations of cytokine blockers (infliximab, adalimumab and ustekinumab) and endoscopic remission of small bowel lesions. METHOD: This was a cross-sectional study conducted at a single tertiary referral centre. Patients with Crohn's disease who received maintenance cytokine blocker therapy were recruited from April 2018 to May 2020. We performed balloon-assisted enteroscopy and collected serum samples to measure drug concentrations. The primary endpoint was the relationship between the concentrations of cytokine blockers and endoscopic remission in the small bowel. RESULTS: We enrolled 143 patients, 66, 44 and 33 of whom were receiving infliximab, adalimumab and ustekinumab, respectively. Enteroscopic findings showed that the rate of endoscopic remission of small bowel lesions was significantly lower than that of colonic lesions (P < 0.01). For each agent, the mean drug concentration in patients exhibiting endoscopic remission in the small bowel was higher than that observed in patients with endoscopic remission in the colon (but not in the small bowel) or with any active disease (either in the small bowel, colon or both). Patients with infliximab, adalimumab and ustekinumab concentrations >5, 14 and 4 µg/mL were nearly 5.3-, 9.4- and 14.7-times more likely to exhibit endoscopic remission of the small bowel, respectively. CONCLUSIONS: Cytokine blocker treatment was less efficacious for small bowel inflammation than colonic inflammation. Higher serum concentrations were needed to achieve endoscopic remission of small bowel lesions.

Pancolonic endoscopic and histologic evaluation for relapse prediction in patients with ulcerative colitis in clinical remission.

BACKGROUND: Mucosal healing is an important treatment target in patients with ulcerative colitis. AIMS: To explore the optimal colonoscopic strategy to determine the risk for clinical relapse in patients with ulcerative colitis. METHODS: We enrolled 325 consecutive patients with ulcerative colitis in clinical and biochemical remission from April 2018 to March 2019. Five colonic segments were endoscopically and histologically assessed systematically. For endoscopic evaluation, we used three different modes of the Ulcerative Colitis Endoscopic Index of Severity (UCEIS): "original," "worst affected," and "pancolonic." The Geboes score was used for histological evaluation. We prospectively followed up the patients and defined clinical relapse as the primary endpoint. RESULTS: Within 1 year after colonoscopy, 18.2% of patients experienced a clinical relapse. Receiver operating characteristic curve analysis showed areas under the curve of 0.755, 0.817, and 0.852 for the "original," "worst affected," and "pancolonic" groups, respectively; hence, pancolonic UCEIS obtained the highest predictive value. Using the pancolonic UCEIS cutoff value of 3, Kaplan-Meier curve analysis showed that patients with endoscopic activity had a significantly lower relapse-free rate than those with endoscopic remission (P < 0.01). Multivariate analysis demonstrated endoscopic (pancolonic UCEIS >3) and histological (Geboes >3.0) activities as independent risks for relapse (HR: 3.96 and 3.48, respectively). Combining pancolonic UCEIS ≤3 and Geboes score ≤3.0 to provide 1-year relapse avoidance was 92.0% sensitive and 97.0% specific. CONCLUSION: Evaluating disease remission by complete colonoscopy is relevant, and the combination of pancolonic endoscopic and histological evaluations may appropriately evaluate mucosal healing.

Functional analysis of isoflavones using patient-derived human colonic organoids.

Inflammatory bowel disease (IBD) comprises two major subtypes, ulcerative colitis (UC) and Crohn's disease, which are multifactorial diseases that may develop due to genetic susceptibility, dysbiosis, or environmental factors. Environmental triggers of IBD include food-borne factors, and a previous nationwide survey in Japan identified pre-illness consumption of isoflavones as a risk factor for UC. However, the precise mechanisms involved in the detrimental effects of isoflavones on the intestinal mucosa remain unclear. The present study employed human colonic organoids (hCOs) to investigate the functional effect of two representative isoflavones, genistein and daidzein, on human colonic epithelial cells. The addition of genistein to organoid reformation assays significantly decreased the number and size of reformed hCOs compared with control and daidzein treatment, indicating an inhibitory effect of genistein on colonic cell/progenitor cell function. Evaluation of the phosphorylation status of 49 different receptor tyrosine kinases showed that genistein selectively inhibited phosphorylation of epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor (HGFR). We established a two-dimensional wound-repair model using hCOs and showed that genistein significantly delayed the overall wound-repair response. Our results collectively show that genistein may exert its detrimental effects on the intestinal mucosa via negative regulation of stem/progenitor cell function, possibly leading to sustained mucosal injury and the development of UC.

Substantial Epstein-Barr virus reactivation in a case of severe refractory ulcerative colitis: a possible role in exacerbation.

Ulcerative colitis (UC) is an inflammatory bowel disease that causes chronic inflammation in the colon. 5-aminosalicylic acid and immunosuppressive medications such as corticosteroids, immunomodulators, and biologic agents are used to treat these patients. However, patients with UC who receive immunosuppressive medications may be at risk for certain opportunistic infections. Epstein-Barr virus (EBV) is one of those opportunistic infections, and its pathogenic role has been implicated in refractory UC, but its pathogenicity should be further investigated. Here, we report a surgical case of refractory UC that demonstrated a serologically post-infected pattern of EBV at admission but that later had a high load of EBV in both the peripheral blood and colonic mucosa. These findings suggest that EBV may have been reactivated in the colon, after which it damaged the colonic mucosa and aggravated inflammation in this patient with UC. Thus, EBV might lead to severity and a refractory response against corticosteroids and anti-TNFα agents, necessitating emergency surgery. Viral surveillance for EBV in patients with refractory UC may facilitate understanding of the patient's pathophysiology and predicting response to medications, and the development of antiviral intervention for those patients may improve their prognosis.

Notch and TNF-α signaling promote cytoplasmic accumulation of OLFM4 in intestinal epithelium cells and exhibit a cell protective role in the inflamed mucosa of IBD patients.

Notch signaling is activated in the intestinal epithelial cells (IECs) of patients with inflammatory bowel disease (IBD), and contributes to mucosal regeneration. Our previous study indicated that TNF-α and Notch signaling may synergistically promote the expression of the intestinal stem cell (ISC) marker OLFM4 in human IECs. In the present study, we investigated the gene regulation and function of OLFM4 in human IEC lines. We confirmed that TNF-α and Notch synergistically upregulate the mRNA expression of OLFM4. Luciferase reporter assay showed that OLFM4 transcription is regulated by the synergy of TNF-α and Notch. At the protein level, synergy between TNF-α and Notch promoted cytoplasmic accumulation of OLFM4, which has potential anti-apoptotic properties in human IECs. Analysis of patient-derived tissues and organoids consistently showed cytoplasmic accumulation of OLFM4 in response to NF-κB and Notch activation. Cytoplasmic accumulation of OLFM4 in human IECs is tightly regulated by Notch and TNF-α in synergy. Such cytoplasmic accumulation of OLFM4 may have a cell-protective role in the inflamed mucosa of patients with IBD.