Anti-integrin αvß6 autoantibodies are a potential biomarker for ulcerative colitis-like immune checkpoint inhibitor-induced colitis.

BACKGROUND: No specific biomarker for immune checkpoint inhibitor (ICI)-induced colitis has been established. Previously, we identified anti-integrin αvß6 autoantibodies in >90% of patients with ulcerative colitis (UC). Given that a subset of ICI-induced colitis is similar to UC, we aimed to clarify the relationship between such autoantibodies and ICI-induced colitis. METHODS: Serum anti-integrin αvß6 autoantibody levels were compared between 26 patients with ICI-induced colitis and 157 controls. Endoscopic images of ICI-induced colitis were centrally reviewed. Characteristics of anti-integrin αvß6 autoantibodies in the ICI-induced colitis patients were compared with those of UC patients. RESULTS: Anti-integrin αvß6 autoantibodies were found in 8/26 (30.8%) patients with ICI-induced colitis and 3/157 (1.9%) controls (P < 0.001). Patients with anti-integrin αvß6 autoantibodies had significantly more typical UC endoscopic features than those without the autoantibodies (P < 0.001). Anti-integrin αvß6 autoantibodies in ICI-induced colitis patients were associated with grade ≥3 colitis (P = 0.001) and steroid resistance (P = 0.005). Anti-integrin αvß6 autoantibody titers correlated with ICI-induced colitis disease activity. Anti-integrin αvß6 autoantibodies of ICI-induced colitis exhibited similar characteristics to those of UC. CONCLUSIONS: Anti-integrin αvß6 autoantibodies may serve as potential biomarkers for the diagnosis, classification, risk management, and monitoring the disease activity, of ICI-induced colitis.

Hepatic abscess induced by gastric cancer mimicking differentiated hepatocellular carcinoma.

A 58-year-old man was referred to our hospital with right abdominal pain. Contrast-enhanced computed tomography (CECT) showed a rim-enhanced lesion with a fluid collection in the right hepatic lobe. Upper gastrointestinal endoscopy revealed a Borrmann type 1 tumor on the middle gastric body, identified as an adenocarcinoma on pathology. The patient underwent percutaneous transhepatic abscess drainage and was treated with antibiotics. Two weeks after drainage, CECT revealed shrinkage of the abscess; however, the wall showed contrast enhancement. Needle biopsy was performed for the liver tumor, and it suggested the possibility of highly differentiated hepatocellular carcinoma. The patient first underwent gastrectomy, and the liver tumor was followed with CECT. Two months after surgery, CECT revealed that the liver tumor had vanished. Liver abscesses and infectious tumors can be difficult to differentiate between; therefore, careful scrutiny is essential before treatment.

The Safety and Clinical Validity of Endoscopic Submucosal Dissection for Early Gastric Cancer in Patients Aged More Than 85 Years.

Endoscopic submucosal dissection (ESD) is a safe and minimally invasive method for the treatment of early gastric cancer (EGC). However, whether ESD for EGC is also safe and feasible in patients aged ≥85 years is unclear. The patients enrolled in this study were divided into three groups: age ≥85 years (44 patients, 49 lesions), age 65−84 years (624 patients, 687 lesions), and age ≤64 years (162 patients, 174 lesions). We evaluated the incidence of adverse events (AEs) and overall survival (OS) and disease-specific survival (DSS). We analyzed the factors that had a significant impact on the prognosis of patients aged ≥85 years. No significant differences were found in the incidence of AEs among the three groups (p = 0.612). The OS was significantly lower in patients aged ≥85 years (p < 0.001). Conversely, DSS was not significantly worse in patients aged ≥85 years (p = 0.100). The poor Geriatric Nutritional Risk Index correlated with poor prognosis in patients aged ≥85 years (p < 0.001). ESD is a safe and valid treatment for EGC in patients aged ≥85 years. However, the indications should be carefully decided because it is difficult to estimate the survival contribution of ESD for EGC in patients aged ≥85 years, especially in those with poor nutritional status.

Clinical impact of a novel device delivery system in the diagnosis of bile duct lesions: A single-center experience.

BACKGROUND AND AIM: Pathological evaluation is essential for the diagnosis of biliary tract diseases. However, existing evaluation methods have various challenges in terms of operability and diagnostic performance. The present study aimed to evaluate the feasibility, utility, and safety of a novel device delivery system for bile duct biopsy. METHODS: This study was conducted as a retrospective, descriptive analysis at a single center. Overall, 25 examinations in 14 consecutive patients who underwent transpapillary biopsies for biliary lesions using the novel device delivery system from July to November 2020 were reviewed. Number and time of biopsy, technical success rate, adequate tissue sampling rate, adverse events, and diagnostic performance of bile duct biopsies using the novel device were evaluated. Moreover, negative surgical margins were assessed in patients who underwent surgical resection after mapping biopsy. RESULTS: The median number of biopsy samples was five (range: 2-13), with a median biopsy time of 11.6 min. The technical success rate was 100% (140/140), with an adequate sampling rate of 82.9% (116/140). These rates did not differ depending on the biopsy site or purpose. There were no serious adverse events related to the procedures. The diagnostic sensitivity, specificity, and accuracy of biliary stricture were 90%, 100%, and 92.3%, respectively. Negative surgical margins were confirmed in all patients undergoing surgical resection, including one patient with a surgical procedure changed based on the results of mapping biopsy. CONCLUSIONS: The novel device delivery system has potentials in diagnosing biliary tract diseases and determining appropriate treatment strategies.

Reducing the risk of developing walled-off necrosis in patients with acute necrotic collection using recombinant human soluble thrombomodulin.

BACKGROUND/PURPOSE: The purpose of the present study was to investigate the possibility of reducing clinical impacts of acute necrotic collection (ANC) on patients with acute pancreatitis (AP) using recombinant human soluble thrombomodulin (rTM). METHODS: In this retrospective multicenter study, 233 consecutive AP patients with ANC and acute peripancreatic fluid collection (APFC) from 2012 to 2016 were enrolled. To assess clinical impacts of ANC, severity on admission (JPN score, JPN CT grade, and Modified CT severity index), development of walled-off necrosis (WON), imaging costs for follow-up, and mortality were recorded. Finally, we investigated whether rTM could reduce the clinical impacts, adjusting the severity using propensity analysis with Inverse probability of treatment weighting. RESULTS: Patients with ANC developed WON with higher ratio than APFC (58/98 [59.2%] vs 20/135 [14.8%], OR = 8.3, P < .01]. Severity on admission and imaging costs for follow-up in ANC patients were significantly higher than those in APFC (P < .01). However, regarding mortality, there was no significant difference between patients with ANC and APFC (P = .41). Adjusting severity, it was revealed that rTM administration significantly reduced the risk of ANC developed WON (OR = 0.23, P = .01). CONCLUSIONS: While ANC had a higher clinical impact than that of APFC, we found that early administration of rTM may reduce the impact.

Essential role of Notch/Hes1 signaling in postnatal pancreatic exocrine development.

BACKGROUND: Notch/Hes1 signaling has been shown to play a role in determining the fate of pancreatic progenitor cells. However, its function in postnatal pancreatic maturation is not fully elucidated. METHODS: We generated conditional Hes1 knockout and/or Notch intracellular domain (NICD) overexpression mice in Ptf1a- or Pdx1-positive pancreatic progenitor cells and analyzed pancreatic tissues. RESULTS: Both Ptf1acre/+; Hes1f/f and Ptf1acre/+; Rosa26NICD mice showed normal pancreatic development at P0. However, exocrine tissue of the pancreatic tail in Ptf1acre/+; Hes1f/f mice atrophied and was replaced by fat tissue by 4 weeks of age, with increased apoptotic cells and fewer centroacinar cells. This impaired exocrine development was completely rescued by NICD overexpression in Ptf1acre/+; Hes1f/f; Rosa26NICD mice, suggesting compensation by a Notch signaling pathway other than Hes1. Conversely, Pdx1-Cre; Hes1f/f mice showed impaired postnatal exocrine development in both the pancreatic head and tail, revealing that the timing and distribution of embryonic Hes1 expression affects postnatal exocrine tissue development. CONCLUSIONS: Notch signaling has an essential role in pancreatic progenitor cells for the postnatal maturation of exocrine tissue, partly through the formation of centroacinar cells.

Risk factor analysis for early rebleeding after endoscopic treatment for colonic diverticular bleeding with stigmata of recent hemorrhage.

BACKGROUND AND AIM: Colonic diverticular bleeding is a common cause of acute lower gastrointestinal bleeding. Endoscopic hemostasis is generally selected as the first-line treatment; however, a considerable number of patients experience early rebleeding after endoscopic treatment. We investigated the risk factors for early rebleeding after endoscopic treatment. METHODS: We retrospectively evaluated the data of 142 consecutive patients who underwent endoscopic treatment (endoscopic clipping or endoscopic band ligation) for colonic diverticular bleeding with stigmata of recent hemorrhage between April 2012 and April 2020. Multivariate logistic regression analysis was conducted to evaluate the statistical relationship between patient characteristics and the incidence of early rebleeding occurring within 30 days after endoscopic treatment. RESULTS: Of 142 patients, early rebleeding was detected in 34 (23.9%) patients. According to univariate analysis, platelet count of <10 × 104/µL, bleeding from the left-sided colon, and endoscopic clipping usage were associated with early rebleeding (P < 0.05). The subsequent multivariate logistic regression analysis identified bleeding from the left-sided colon (odds ratio [OR], 4.16; 95% confidence interval [CI], 1.73-10.0; P = 0.001) and endoscopic clipping usage (OR, 2.92; 95% CI, 1.21-7.00; P = 0.017) as the independent risk factors for early rebleeding. CONCLUSIONS: Bleeding from the left-sided colon and endoscopic clipping usage were the risk factors for early rebleeding after endoscopic treatment. Using endoscopic band ligation was associated with a decreased risk for early rebleeding compared with the use of endoscopic clipping, indicating that endoscopic band ligation was a preferable endoscopic modality to prevent early recurrent bleeding.

Identification of an Anti-Integrin αvß6 Autoantibody in Patients With Ulcerative Colitis.

BACKGROUND AND AIMS: Ulcerative colitis is the most frequent type of inflammatory bowel disease and is characterized by colonic epithelial cell damage. Although involvement of autoimmunity has been suggested in ulcerative colitis, specific autoantigens/antibodies have yet to be elucidated. METHODS: Using 23 recombinant integrin proteins, we performed enzyme-linked immunosorbent assays on sera from patients with ulcerative colitis and controls. Integrin expression and IgG binding in the colon tissues of patients with ulcerative colitis and controls were examined using immunofluorescence and coimmunoprecipitation, respectively. The blocking activity of autoantibodies was examined using solid-phase binding and cell adhesion assays. RESULTS: Screening revealed that patients with ulcerative colitis had IgG antibodies against integrin αvß6. In the training and validation groups, 103 of 112 (92.0%) patients with ulcerative colitis and only 8 of 155 (5.2%) controls had anti-integrin αvß6 antibodies (P < .001), resulting in a sensitivity of 92.0% and a specificity of 94.8% for diagnosing ulcerative colitis. Anti-integrin αvß6 antibody titers coincided with ulcerative colitis disease activity, and IgG1 was the major subclass. Patient IgG bound to the integrin αvß6 expressed on colonic epithelial cells. Moreover, IgG of patients with ulcerative colitis blocked integrin αvß6-fibronectin binding through an RGD (Arg-Gly-Asp) tripeptide motif and inhibited cell adhesion. CONCLUSIONS: A significant majority of patients with ulcerative colitis had autoantibodies against integrin αvß6, which may serve as a potential diagnostic biomarker with high sensitivity and specificity.

A novel technique for mapping biopsy of bile duct cancer.

BACKGROUND : Accurate preoperative assessment of the longitudinal extension of perihilar cholangiocarcinoma (PHCC) is essential for treatment planning. Mapping biopsies for PHCC remain challenging owing to technical difficulties and insufficient sample amounts. The aim of this study was to investigate the usefulness of a novel technique for mapping biopsies of PHCC. METHODS : Our novel method focused on a biliary stent delivery system for mapping biopsies. Fifty patients with PHCC undergoing endoscopic transpapillary mapping biopsy using the novel method were reviewed from August 2015 to June 2019. RESULTS : The median number of biopsy samples was six (range 1 - 17), and the rate of adequate sampling was 91.4 % (266 /291). Biopsy from the intrahepatic bile duct was possible in 82.0 % of patients (41 /50), and negative margins were confirmed in the resected specimens from 34 /39 patients who underwent surgery (87.2 %). None of the patients had post-endoscopic retrograde cholangiopancreatography pancreatitis. CONCLUSIONS : With our novel method, accurate assessment of the longitudinal extension of PHCC might be expected with minimal trauma to the duodenal papilla.

Obstructive Colitis with Minor Perforation Induced by Double Sigmoid Adenocarcinoma.

A 72-year-old women was referred to our hospital because of lower left abdominal pain. Computed tomography showed prominent sigmoid colon dilation and double tumors on both the oral and anal sides. Surgical resection revealed an expanded sigmoid colon involved in double cancer that showed strong adhesion to the surrounding tissues. The pathological findings revealed obstructive colitis and minor perforation in the dilated colon. The minor perforation was considered to have been caused by fecal impaction in the closed cavity between the two tumors, resulting in an increase in colon pressure.

Hes1 Is Essential in Proliferating Ductal Cell-Mediated Development of Intrahepatic Cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (ICC) is frequently driven by aberrant KRAS activation and develops in the liver with chronic inflammation. Although the Notch signaling pathway is critically involved in ICC development, detailed mechanisms of Notch-driven ICC development are still unknown. Here, we use mice whose Notch signaling is genetically engineered to show that the Notch signaling pathway, specifically the Notch/Hes1 axis, plays an essential role in expanding ductular cells in the liver with chronic inflammation or oncogenic Kras activation. Activation of Notch1 enhanced the development of proliferating ductal cells (PDC) in injured livers, while depletion of Hes1 led to suppression. In correlation with PDC expansion, ICC development was also regulated by the Notch/Hes1 axis and suppressed by Hes1 depletion. Lineage-tracing experiments using EpcamcreERT2 mice further confirmed that Hes1 plays a critical role in the induction of PDC and that ICC could originate from PDC. Analysis of human ICC specimens showed PDC in nonneoplastic background tissues, confirming HES1 expression in both PDC and ICC tumor cells. Our findings provide novel direct experimental evidence that Hes1 plays an essential role in the development of ICC via PDC. SIGNIFICANCE: This study contributes to the identification of the cells of origin that initiate ICC and suggests that HES1 may represent a therapeutic target in ICC.

CXCR4 in Tumor Epithelial Cells Mediates Desmoplastic Reaction in Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) features abundant stromal cells with an excessive extracellular matrix (ECM), termed the desmoplastic reaction. CXCR4 is a cytokine receptor for stromal cell-derived factor-1 (CXCL12) expressed in PDAC, but its roles in PDAC and the characteristic desmoplastic reaction remain unclear. Here, we generated a mouse model of PDAC with conditional knockout of Cxcr4 (KPC-Cxcr4-KO) by crossing Cxcr4 flox mice with Pdx1-Cre;KrasLSL-G12D/+;Trp53LSL-R172H/+ (KPC-Cxcr4-WT) mice to assess the development of pancreatic intraepithelial neoplasia (PanIN) and pancreatic cancers. Tumor cell characteristics of those two types were analyzed in vitro. In addition, CXCR4 expression in human pancreatic cancer specimens was evaluated by IHC staining. In KPC-Cxcr4-KO mice, the number and pathologic grade of PanIN lesions were reduced, but the frequency of pancreatic cancers did not differ from that in KPC-Cxcr4-WT mice. The pancreatic tumor phenotype in KPC-Cxcr4-KO mice was significantly larger and undifferentiated, characterized by abundant vimentin-expressing cancer cells, significantly fewer fibroblasts, and markedly less deposition of ECM. In vitro, KPC-Cxcr4-KO tumor cells exhibited higher proliferative and migratory activity than KPC-Cxcr4-WT tumor cells. Myofibroblasts induced invasion activity in KPC-Cxcr4-WT tumor cells, showing an epithelial-mesenchymal interaction, whereas KPC-Cxcr4-KO tumor cells were unaffected by myofibroblasts, suggesting their unique nature. In human pancreatic cancer, undifferentiated carcinoma did not express CXCR4 and exhibited histologic and IHC features similar to those in KPC-Cxcr4-KO mice. In summary, the CXCL12/CXCR4 axis may play an important role in the desmoplastic reaction in PDAC, and loss of CXCR4 induces phenotype changes in undifferentiated carcinoma without a desmoplastic reaction. SIGNIFICANCE: The current study uncovers CXCR4 as a key regulator of desmoplastic reaction in PDAC and opens the way for new therapeutic approaches to overcome the chemoresistance in patients with PDAC.

Rb and p53 Execute Distinct Roles in the Development of Pancreatic Neuroendocrine Tumors.

Pancreatic neuroendocrine tumors (PanNET) were classified into grades (G) 1 to 3 by the World Health Organization in 2017, but the precise mechanisms of PanNET initiation and progression have remained unclear. In this study, we used a genetically engineered mouse model to investigate the mechanisms of PanNET formation. Although pancreas-specific deletion of the Rb gene (Pdx1-Cre;Rbf/f ) in mice did not affect pancreatic exocrine cells, the α-cell/ß-cell ratio of islet cells was decreased at 8 months of age. During long-term observation (18-20 months), mice formed well-differentiated PanNET with a Ki67-labeling index of 2.7%. In contrast, pancreas-specific induction of a p53 mutation (Pdx1-Cre;Trp53R172H ) had no effect on pancreatic exocrine and endocrine tissues, but simultaneous induction of a p53 mutation with Rb gene deletion (Pdx1-Cre;Trp53R172H;Rb f/f ) resulted in the formation of aggressive PanNET with a Ki67-labeling index of 24.7% over the short-term (4 months). In Pdx1-Cre;Trp53R172H;Rbf/f mice, mRNA expression of Pten and Tsc2, negative regulators of the mTOR pathway, significantly decreased in the islet cells, and activation of the mTOR pathway was confirmed in subsequently formed PanNET. Thus, by manipulating Rb and p53 genes, we established a multistep progression model from dysplastic islet to indolent PanNET and aggressive metastatic PanNET in mice. These observations suggest that Rb and p53 have distinct roles in the development of PanNET. SIGNIFICANCE: Pancreas-specific manipulation of Rb and p53 genes induced malignant transformation of islet cells, reproducing stepwise progression from microadenomas to indolent (grade 1) and subsequent aggressive PanNETs (grade 2-3).

Utility of laser-cut covered self-expandable metal stents for unresectable malignant distal biliary obstruction: a single-center experience.

BACKGROUND: Few reports have evaluated the effectiveness of laser-cut, covered, self-expandable metal stents (LC-CSEMS) for unresectable malignant distal biliary obstruction (MDBO) and whether reintervention is feasible after placement. We describe our experience with LC-CSEMS placement for unresectable MDBO. METHODS: Patients undergoing LC-CSEMS placement for unresectable MDBO from November 2014 to December 2018 were reviewed. Recurrent biliary obstruction (RBO), median time to RBO (TRBO), and reintervention were analyzed. RESULTS: 52 patients who underwent LC-CSEMS placement for unresectable MDBO were included in the analysis. The RBO rate was 15 % and the median TRBO was 445 days. Reintervention was attempted in nine patients and stent removal was successful in eight patients. CONCLUSIONS: Our experience suggests the effectiveness of LC-CSEMS in patients with unresectable MDBO in terms of stent patency and feasibility of reintervention.

Hes1 plays an essential role in Kras-driven pancreatic tumorigenesis.

Most pancreatic ductal adenocarcinoma (PDAC) develops from pancreatic epithelial cells bearing activating mutant KRAS genes through precancerous lesions, i.e. acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN). During pancreatic tumorigenesis, Hes1 expression starts with the transition from acinar cells to ADM, and continues during PanIN and PDAC formation, but the role of Hes1 in pancreatic tumorigenesis is not fully elucidated. Here we show that Hes1 plays an essential role in the initiation and progression of KRAS-driven pancreatic tumorigenesis. In vitro, activation of MAPK signaling due to EGF or mutant KRAS activation induced sustained Hes1 expression in pancreatic acinar cells. In vivo, acinar cell-specific activation of mutant KRAS by Elastase1-CreERT2;KrasG12D induced ADM/PanIN formation with Hes1 expression in mice, and genetic ablation of Hes1 in these mice dramatically suppressed PanIN formation. Gene expression analysis and lineage tracing revealed that Hes1 regulates acinar-to-ductal reprogramming-related genes and, in a Hes1-deficient state, mutant Kras-induced ADM could not progress into PanIN, but re-differentiated into acinar cells. In the Elastase1-CreERT2;KrasG12D;Trp53R172H mouse PDAC model, genetic ablation of Hes1 completely blocked PDAC formation by keeping PanIN lesions in low-grade conditions, in addition to reducing the occurrence of PanIN. Together, these findings indicate that mutant KRAS-induced Hes1 plays an essential role in PDAC initiation and progression by regulating acinar-to-ductal reprogramming-related genes.

Laminin 511 is a target antigen in autoimmune pancreatitis.

Autoimmune pancreatitis (AIP), a major manifestation of immunoglobulin G4-related disease (IgG4-RD), is an immune-mediated disorder, but the target autoantigens are still unknown. We previously reported that IgG in patients with AIP induces pancreatic injuries in mice by binding the extracellular matrix (ECM). In the current study, we identified an autoantibody against laminin 511-E8, a truncated laminin 511, one of the ECM proteins, in patients with AIP. Anti-laminin 511-E8 IgG was present in 26 of 51 AIP patients (51.0%), but only in 2 of 122 controls (1.6%), by enzyme-linked immunosorbent assay. Because truncated forms of other laminin family members in other organs have been reported, we confirmed that truncated forms of laminin 511 also exist in human and mouse pancreas. Histologic studies with patient pancreatic tissues showed colocalization of patient IgG and laminin 511. Immunization of mice with human laminin 511-E8 induced antibodies and pancreatic injury, fulfilling the pathologic criteria for human AIP. Four of 25 AIP patients without laminin 511-E8 antibodies had antibodies against integrin α6ß1, a laminin 511 ligand. AIP patients with laminin 511-E8 antibodies exhibited distinctive clinical features, as the frequencies of malignancies or allergic diseases were significantly lower in patients with laminin 511-E8 antibodies than in those without. The discovery of these autoantibodies should aid in the understanding of AIP pathophysiology and possibly improve the diagnosis of AIP.