A role of the aryl hydrocarbon receptor in attenuation of colitis

BACKGROUND AND AIMS

The aryl hydrocarbon receptor (AhR), which is a member of the basic helix-loop-helix/Per-Arnt-Sim homology superfamily, plays an important role in multiple biological functions, and AhR knockout (AhR KO) animals suffer from a variety of organ disorders including a decline in the efficacy of their immune system. In addition, AhR activation is known to aid the maintenance of homeostasis in vivo. In this study, we investigated whether AhR is functionally associated with intestinal immunity.

METHODS AND RESULTS

In in vivo experiments, it was found that dextran sodium sulfate (DSS)-evoked colitis was more severe in AhR KO mice than in C57BL/6J wild type mice. It was also revealed that the administration of DSS increased the expression levels of AhR and CYP1A1 mRNA in the colon epithelium. In addition, oral administration of β-naphthoflavone (βNF), a non-toxic agonist of AhR, suppressed the pathogenesis of DSS-induced colitis. βNF also attenuated DSS-induced colitis. In cell culture experiments, downregulation of AhR in human colon carcinoma SW480 cells enhanced the inflammatory responses evoked by lipopolysaccharide (LPS), and furthermore, AhR activation attenuated LPS-induced inflammatory responses, suggesting that AhR expressing intestinal epithelial cells are involved in the prevention of colitis.

CONCLUSIONS

Our findings about the potential role of AhR activators in epithelial immune regulation aid our understanding of mucosal homeostasis and inflammatory bowl disease (IBD) and suggest that AhR activation has therapeutic value for the treatment of IBD.

GCMS-based metabolomic study in mice with colitis induced by dextran sulfate sodium

BACKGROUND

Metabolomics provides data about all the metabolic processes of a cell or organism. So far, the changes that occur in the levels of metabolites during the development of colitis have not been fully elucidated. Here we examined the changes of metabolite levels in the serum and colon tissue of colitis mice using gas chromatography mass spectrometry (GC/MS) with the aim of achieving a detailed understanding of the pathogenesis of inflammatory bowel disease (IBD).

METHODS

To induce colitis, C57BL/6J mice were administered 3.0% dextran sulfate sodium (DSS) in their drinking water for 5 days and were subsequently given drinking water alone.

RESULTS

A total of 77 and 92 metabolites were detected in serum and colon tissue, respectively, and among the metabolites the compositions of TCA cycle intermediates and amino acids changed depending on the degree of colitis. Then, partial least square discriminant analysis (PLS-DA), a multiple classification analysis, showed distinct clustering and clear separation of the groups according to the degree of colitis. Furthermore, PLS-DA loadings plots revealed that succinic acid, indole-3-acetic acid, glutamic acid, and glutamine were the main contributors to the separation of each stage of colitis. In addition, it was revealed that supplementation with glutamine, the level of which was significantly decreased in the acute phase of colonic inflammation, attenuated colitis induced by DSS.

CONCLUSIONS

Our results suggest that metabolomics is capable of representing the various degrees of colitis, and our findings will aid in the discovery of therapeutic agents for IBD and other inflammatory disorders by metabolomic approaches.

Clinical outcome of conservatively managed pancreatic intraductal papillary mucinous neoplasms with mural nodules and main duct dilation

BACKGROUND

Surgical resection of intraductal papillary mucinous neoplasm (IPMN) is strongly recommended for patients exhibiting high-risk stigmata (HRS). However, determining surgical indications for elderly patients with comorbidities is challenging, as clinical outcomes are not well characterized. This multicenter observational study elucidated the clinical outcomes of patients with IPMN exhibiting HRS who did not undergo surgery.

METHODS

This study enrolled 101 IPMN patients exhibiting HRS with follow-up observations at 11 hospitals in Japan (2011-2016). The median observation period was 37 months (maximum: 86 months). Primary outcomes were estimated 5-year overall survival (OS) and disease-specific survival (DSS). Survival was also stratified based on HRS features.

RESULTS

Of 101 patients, 32 (31.7%) had the main pancreatic duct (MPD) measuring ≥ 10 mm and 80 (79.2%) had mural nodules measuring ≥ 5 mm. The estimated 5-year OS and DSS were 74% and 91%, respectively. In the stratified analysis, the co-presence of MPD ≥ 10 mm and mural nodules ≥ 5 mm or mural nodule ≥ 10 mm were related to worse 5-year DSS (MPD ≥ 10 mm and mural nodules ≥ 5 mm vs other characteristics: 60% vs 95%, log-rank test: p = 0.049; mural nodules ≥ 10 mm vs < 10 mm: 77% vs 95%, log-rank test: p = 0.003).

CONCLUSIONS

The estimated 5-year DSS of conservatively managed IPMN patients with mural nodules and main duct dilation was 91%. Only IPMN patients with plural HRS or large nodule formation might have an increased mortality risk. This is an important insight that can help facilitate appropriate clinical decision-making, especially in the elderly or high-surgical risk IPMN patients.

A novel fully covered metal stent for unresectable malignant distal biliary obstruction: results of a multicenter prospective study

BACKGROUND/AIMS

Endoscopic self-expandable metal stent (SEMS) placement is currently the standard technique for treating unresectable malignant distal biliary obstructions (MDBO). Therefore, covered SEMS with longer stent patency and fewer migrations are required. This study aimed to assess the clinical performance of a novel, fully covered SEMS for unresectable MDBO.

METHODS

This was a multicenter single-arm prospective study. The primary outcome was a non-obstruction rate at 6 months. The secondary outcomes were overall survival (OS), recurrent biliary obstruction (RBO), time to RBO (TRBO), technical and clinical success, and adverse events.

RESULTS

A total of 73 patients were enrolled in this study. The non-obstruction rate at 6 months was 61%. The median OS and TRBO were 233 and 216 days, respectively. The technical and clinical success rates were 100% and 97%, respectively. Furthermore, the rate of occurrence of RBO and adverse events was 49% and 21%, respectively. The length of bile duct stenosis (<2.2 cm) was the only significant risk factor for stent migration.

CONCLUSIONS

The non-obstruction rate of a novel fully covered SEMS for MDBO is comparable to that reported earlier but shorter than expected. Short bile duct stenosis is a significant risk factor for stent migration.

Relapse and side effects of steroid therapy beyond 3 years in autoimmune pancreatitis: A multicenter retrospective study

BACKGROUND

The impact of extended steroid administration on patients with autoimmune pancreatitis after a 3-year maintenance period remains poorly understood. This study analyzed the advantage and disadvantage of continuing steroid therapy beyond 3 years.

METHODS

In this retrospective multicenter study across 17 institutions, patients who successfully completed 3 years of maintenance therapy without experiencing relapse were categorized into two groups: the maintenance therapy discontinuation group, who discontinued steroid therapy after the initial 3-year period, and maintenance therapy continuation group, who continued steroid therapy beyond 3 years. The cumulative relapse rate after 3 years of maintenance therapy was the primary outcome. Relapse predictors were compared using the Gray test for cumulative relapse incidence by specific factor.

RESULTS

Of 211 patients, 105 experienced no relapse during the 3-year maintenance therapy and were divided into two groups: 69 in the maintenance therapy discontinuation group and 36 in the maintenance therapy continuation group. The relapse rate was lower in the maintenance therapy continuation group than in the maintenance therapy discontinuation group (P = 0.035). Predictors of relapse after 3 years included cessation of maintenance therapy (hazard ratio [HR] = 3.76; 95 % confidence interval [CI] = 1.07-13.3, P = 0.040) and renal involvement (HR = 2.88; 95 % CI = 1.04-7.99, P = 0.042). The maintenance therapy continuation group showed a significantly higher prevalence of macrovascular complications, compared with the maintenance therapy discontinuation group (P = 0.005).

CONCLUSIONS

Cessation of steroid maintenance therapy and renal involvement were predictors of relapse after 3 years of maintenance therapy. However, the long-term use of steroids may increase the risk of macrovascular complications.

Pancreatic injury in patients treated with immune checkpoint inhibitors: a retrospective multicenterstudy

BACKGROUND

Immune checkpoint inhibitor-related pancreatic injury (ICI-PI) is a rare occurrence, which has not been reported in detail. We conducted a retrospective multicenter study to determine the clinical characteristics, risk factors, and treatment of ICI-PI.

METHODS

We reviewed the medical records of patients who received ICIs for malignant tumors between April 2014 and April 2019 at 16 participating hospitals. Patients with elevated pancreatic enzymes or pancreatitis were identified and classified using the Common terminology Criteria for Adverse Events (CTCAE) ver.5.0). The number of patients with pancreatic enzyme elevation was determined and those with pancreatic enzyme elevation of ≥ grade 3 according to CTCAE ver.5.0, or pancreatitis underwent detailed analysis for ICI-PI.

RESULTS

The study enrolled 1069 patients. Nineteen patients (1.8%) had ICI-PI, 5 (0.5%) of whom also had pancreatitis. Four patients had mild pancreatitis, whereas 1 patient had severe pancreatitis, culminating in death. Steroid therapy was administered to 7 of 19 patients, which led to ICI-PI improvement in 5 patients. On the other hand, ICI-PI improved in 9 of 12 patients who were not administered steroid therapy. Six of the 14 patients with ICI-PI improvement were rechallenged with ICI, and ICI-PI relapse occurred in only 1 patient (16.7%), which improved with ICI discontinuation and steroid therapy.

CONCLUSIONS

ICI-PI is a rare occurrence, with a low incidence of pancreatitis, which followed a very serious course in one patient. Although the benefit of steroid therapy for ICI-PI is unclear, ICI rechallenge is acceptable after improvement of ICI-PI without pancreatitis.

Temporal progression of pancreatic cancer computed tomography findings until diagnosis: A large-scale multicenter study

BACKGROUND

Focal parenchymal atrophy and main pancreatic duct (MPD) dilatation have been identified as early signs of pancreatic ductal adenocarcinoma. However, limited evidence exists regarding their temporal progression due to previous study limitations with restricted case numbers.

OBJECTIVE

To ascertain a more precise frequency assessment of suspicious pancreatic ductal adenocarcinoma findings as well as delineate the temporal progression of them.

METHODS

A multicenter retrospective study was conducted on patients diagnosed with pancreatic ductal adenocarcinoma between 2015 and 2021. We included patients who had undergone at least one computed tomography (CT) scan ≥6 months before diagnosing pancreatic ductal adenocarcinoma. The temporal progression of suspicious pancreatic ductal adenocarcinoma findings on CT was investigated.

RESULTS

Out of 1832 patients diagnosed with pancreatic ductal adenocarcinoma, 320 had a previous CT before their diagnosis. Suspicious pancreatic ductal adenocarcinoma findings were detected in 153 cases (47.8%), with focal parenchymal atrophy (26.6%) being the most common followed by MPD dilatation (11.3%). Focal parenchymal atrophy was the earliest detectable sign among all suspicious findings and became visible on average 2.7 years before diagnosis, and the next most common, MPD dilatation, 1.1 years before diagnosis. Other findings, such as retention cysts, were less frequent and appeared around 1 year before diagnosis. Focal parenchymal atrophy followed by MPD dilatation was observed in 10 patients but not in reverse order. Focal parenchymal atrophy was more frequently detected in the pancreatic body/tail. No significant relationship was found between the pathological pancreatic ductal adenocarcinoma differentiation or tumor stage and the time course of the CT findings. All cases of focal parenchymal atrophy progressed just prior to diagnosis, and the atrophic area was occupied by tumor at diagnosis. Main pancreatic duct dilatation continued to progress until diagnosis.

CONCLUSION

This large-scale study revealed that the temporal progression of focal parenchymal atrophy is the earliest detectable sign indicating pancreatic ductal adenocarcinoma. These results provide crucial insights for early pancreatic ductal adenocarcinoma detection.

The anti-migration effect of partially covered self-expandable metal stents for unresectable malignant distal biliary obstruction: A multicenter comparative study

Objectives

Covered self-expandable metal stents are commonly used for unresectable malignant distal biliary obstruction. Partially covered self-expandable metal stents have uncovered sections at both ends; however, their anti-migration effect remains unclear. The objective of this study was to evaluate that effect by comparing such stents with fully covered self-expandable metal stents for patients with unresectable malignant distal biliary obstruction.

Methods

This was a multicenter, retrospective comparative study of partially covered stents with fully covered stents for unresectable malignant distal biliary obstruction. Stent migration, recurrent biliary obstruction, and the time to recurrent biliary obstruction were compared between them.

Results

Thirty-nine patients with partially covered stents were included and compared with 42 patients with fully covered stents. The partially covered group had a significantly lower stent migration rate (3% vs. 36%; p < 0.001). The recurrent biliary obstruction rate was significantly lower in the partially covered group (21% vs. 43%; p = 0.036). The non-recurrent biliary obstruction rate at 6 months was 90% and 68% in the partially and fully covered groups, respectively. The time to recurrent biliary obstruction was significantly longer in the partially covered group (Gray's test, p = 0.016). Only partially covered stent placement was significantly associated with a lower risk of stent migration (subdistribution hazard ratio = 0.077; 95% confidence interval = 0.01-0.60; p = 0.014) in the multivariable analysis.

Conclusions

The anti-migration effect of partially covered self-expandable metal stents was associated with a reduced recurrence of biliary obstruction and prolonged time to such obstruction.