Adverse events of self-expandable metal stent placement for malignant distal biliary obstruction: a large multicenter study.

BACKGROUND AND AIMS: Endoscopic placement of self-expandable metal stents (SEMSs) for malignant distal biliary obstruction (MDBO) may be accompanied by several types of adverse events. The present study analyzed the adverse events occurring after SEMS placement for MDBO. METHODS: The present study retrospectively investigated the incidence and types of adverse events in patients who underwent SEMS placement for MDBO between April 2018 and March 2021 at 26 hospitals. Risk factors for acute pancreatitis, cholecystitis, and recurrent biliary obstruction (RBO) were evaluated by univariate and multivariate analyses. RESULTS: Of the 1425 patients implanted with SEMSs for MDBO, 228 (16.0%) and 393 (27.6%) experienced early adverse events and RBO, respectively. Pancreatic duct without tumor involvement (P = .023), intact papilla (P = .025), and SEMS placement across the papilla (P = .037) were independent risk factors for acute pancreatitis. Tumor involvement in the orifice of the cystic duct was an independent risk factor for cholecystitis (P < .001). Use of fully and partially covered SEMSs was an independent risk factor for food impaction and/or sludge. Use of fully covered SEMSs was an independent risk factor for stent migration. Use of uncovered SEMSs and laser-cut SEMSs was an independent risk factor for tumor ingrowth. CONCLUSIONS: Pancreatic duct without tumor involvement, intact papilla, and SEMS placement across the papilla were independent risk factors for acute pancreatitis, and tumor involvement in the orifice of the cystic duct was an independent risk factor for cholecystitis. The risk factors for food impaction and/or sludge, stent migration, and tumor ingrowth differed among types of SEMSs.

Context-Dependent Roles of Hes1 in the Adult Pancreas and Pancreatic Tumor Formation.

BACKGROUND & AIMS: The Notch signaling pathway is an important pathway in the adult pancreas and in pancreatic ductal adenocarcinoma (PDAC), with hairy and enhancer of split-1 (HES1) as the core molecule in this pathway. However, the roles of HES1 in the adult pancreas and PDAC formation remain controversial. METHODS: We used genetically engineered dual-recombinase mouse models for inducing Hes1 deletion under various conditions. RESULTS: The loss of Hes1 expression in the adult pancreas did not induce phenotypic alterations. However, regeneration was impaired after caerulein-induced acute pancreatitis. In a pancreatic intraepithelial neoplasia (PanIN) mouse model, PanINs rarely formed when Hes1 deletion preceded PanIN formation, whereas more PanINs were formed when Hes1 deletion succeeded PanIN formation. In a PDAC mouse model, PDAC formation was also enhanced by Hes1 deletion after PanIN/PDAC development; therefore, Hes1 promotes PanIN initiation but inhibits PanIN/PDAC progression. RNA sequencing and chromatin immunoprecipitation-quantitative polymerase chain reaction revealed that Hes1 deletion enhanced epithelial-to-mesenchymal transition via Muc5ac up-regulation in PDAC progression. The results indicated that HES1 is not required for maintaining the adult pancreas under normal conditions, but is important for regeneration during recovery from pancreatitis; moreover, Hes1 plays different roles, depending on the tumor condition. CONCLUSIONS: Our findings highlight the context-dependent roles of HES1 in the adult pancreas and pancreatic cancer.

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.

Long-term Outcomes of Stent Placement Inside the Bile Duct for Biliary Strictures After Living Donor Liver Transplantation.

In living donor liver transplantation (LDLT), anastomotic biliary stricture is a serious and refractory complication. In this study, we reviewed the transition of post-LDLT anastomotic biliary strictures and evaluated long-term outcomes of stent placement inside the bile duct, which is referred to as an "inside-stent." Of 805 consecutive adult LDLT recipients in our institution (2000-2018), we reviewed 639 patients with duct-to-duct biliary reconstruction and analyzed chronological changes of post-LDLT biliary strictures. Moreover, we focused on the year 2006 when various surgical modifications were introduced and compared the details of post-LDLT biliary strictures before and after 2006, especially focusing on the long-term outcome of inside-stent placement. The proportion of left lobe grafts had increased from 1.8% before 2005 to 39.3% after 2006 (P < 0.001) to maximize the living donor safety. Overall, post-LDLT anastomotic biliary strictures occurred in 21.3% of the patients with a median follow-up period of 106.1 months, which was decreased from 32.6% before 2005 to 12.8% after 2006 (P < 0.001). Anastomotic biliary strictures were less frequent in patients with left lobe grafts than with right lobe grafts (9.4% versus 25.4%; P < 0.001). The overall technical success rate of inside-stent placement was 82.4%, with an improvement from 75.3% before 2005 up to 95.7% after 2006 (P < 0.01). Furthermore, the stricture resolution rate remained high at approximately 90% throughout the observation period. Increased use of left lobe grafts with several surgical modifications significantly reduced post-LDLT anastomotic biliary strictures, leading to favorable long-term outcomes of inside-stent placements for this condition.

Plasmacytoid Dendritic Cell Activation and IFN-α Production Are Prominent Features of Murine Autoimmune Pancreatitis and Human IgG4-Related Autoimmune Pancreatitis.

The abnormal immune response accompanying IgG4-related autoimmune pancreatitis (AIP) is presently unclear. In this study, we examined the role of plasmacytoid dendritic cell (pDC) activation and IFN-α production in this disease as well as in a murine model of AIP (MRL/Mp mice treated with polyinosinic-polycytidylic acid). We found that the development of AIP in treated MRL/Mp mice occurred in parallel with pancreatic accumulation of pDCs producing IFN-α, and with pDC depletion and IFN-α-blocking studies, we showed that such accumulation was necessary for AIP induction. In addition, we found that the pancreas of treated MRL/Mp mice contained neutrophil extracellular traps (NETs) shown previously to stimulate pDCs to produce IFN-α. Consistent with these findings, we found that patients with IgG4-related AIP also exhibited pancreatic tissue localization of IFN-α-expressing pDCs and had significantly higher serum IFN-α levels than healthy controls. In addition, the inflamed pancreas of these patients but not controls also contained NETs that were shown to be capable of pDC activation. More importantly, patient pDCs cultured in the presence of NETs produced greatly increased levels of IFN-α and induced control B cells to produce IgG4 (but not IgG1) as compared with control pDCs. These data suggest that pDC activation and production of IFN-α is a major cause of murine AIP; in addition, the increased pDC production of IFN-α and its relation to IgG4 production observed in IgG4-related AIP suggest that this mechanism also plays a role in the human disease.

Pathogenicity of IgG in patients with IgG4-related disease.

OBJECTIVE: IgG4-related disease (IgG4-RD) is a systemic disease characterised by elevated serum IgG4 and IgG4-positive lymphoplasmacytic infiltration in the affected tissues. The pathogenic role of IgGs, including IgG4, in patients with IgG4-RD, however, is unknown. DESIGN: We examined the pathogenic activity of circulating IgGs in patients with IgG4-RD by injecting their IgGs into neonatal male Balb/c mice. Binding of patient IgGs to pancreatic tissue was also analysed in an ex vivo mouse organ culture model and in tissue samples from patients with autoimmune pancreatitis (AIP). RESULTS: Subcutaneous injection of patient IgG, but not control IgG, resulted in pancreatic and salivary gland injuries. Pancreatic injury was also induced by injecting patient IgG1 or IgG4, with more destructive changes induced by IgG1 than by IgG4. The potent pathogenic activity of patient IgG1 was significantly inhibited by simultaneous injection of patient IgG4. Binding of patient IgG, especially IgG1 and IgG4, to pancreatic tissue was confirmed in both the mouse model and AIP tissue samples. CONCLUSIONS: IgG1 and IgG4 from patients with IgG4-RD have pathogenic activities through binding affected tissues in neonatal mice.

Impact of EUS-FNA for preoperative para-aortic lymph node staging in patients with pancreatobiliary cancer.

BACKGROUND AND AIMS: In patients with pancreatobiliary cancer, para-aortic lymph node (PALN) metastasis is considered to be the involvement beyond the regional lymph nodes, namely, distant metastasis. Effective methods for preoperative PALN staging, however, are not established. This study aimed to compare the diagnostic capability for PALN metastasis between EUS-FNA and (18)F-fluorodeoxyglucose positron emission tomography with CT (PET/CT). METHODS: We performed a prospective, nonrandomized, single-center trial. Between December 2010 and March 2014, 208 patients with pancreatobiliary cancer without apparent distant metastasis except for PALNs were assessed for study eligibility before surgery. Among them, 52 consecutive patients with PALN enlargement were enrolled in the study. (18)F-Fluorodeoxyglucose PET/CT and EUS-FNA were performed sequentially as a single combined procedure to evaluate PALN metastases. The primary outcome was to compare the diagnostic capability of EUS-FNA and PET/CT for PALN metastasis. RESULTS: Of 71 enlarged PALNs in the 52 patients, 30 (42.3%) were finally diagnosed as metastases in 21 patients (40.4%). Of the 21 patients with PALN metastases, preoperative EUS-FNA or PET/CT made a correct diagnosis in 20 (95.2%) or 12 (57.1%), respectively. EUS-FNA had higher sensitivity and specificity for the diagnosis of PALN metastasis (sensitivity, 96.7% [29/30]; 95% confidence interval, 82.2%-99.9%; specificity, 100% [39/39]; 95% confidence interval, 91.0%-100%) than PET/CT. CONCLUSIONS: EUS-FNA is superior to PET/CT for preoperative PALN staging in patients with pancreatobiliary cancer. Because of the clinical benefit of EUS-FNA to reduce unnecessary surgery, it should be part of the standard preoperative examination for patients with pancreatobiliary cancer. (UMIN clinical trials registry number: 000006408.).

Risk of cancer in patients with autoimmune pancreatitis.

OBJECTIVES: Although simultaneous occurrences of autoimmune pancreatitis (AIP) and cancer are occasionally observed, it remains largely unknown whether cancer and AIP occur independently or these disorders are interrelated. The aim of this study was to examine the relationship between AIP and cancer. METHODS: We conducted a multicenter, retrospective cohort study. One hundred and eight patients who met the Asian diagnostic criteria for AIP were included in the study. We calculated the proportion, standardized incidence ratio (SIR), relative risk, and time course of cancer development in patients with AIP. We also analyzed the clinicopathological characteristics of AIP patients with cancer in comparison with those without cancer. RESULTS: Of the 108 AIP patients, 18 cancers were found in 15 patients (13.9%) during the median follow-up period of 3.3 years. The SIR of cancer was 2.7 (95% confidence interval (CI) 1.4-3.9), which was stratified into the first year (6.1 (95% CI 2.3-9.9)) and subsequent years (1.5 (95% CI 0.3-2.8)) after AIP diagnosis. Relative risk of cancer among AIP patients at the time of AIP diagnosis was 4.9 (95% CI 1.7-14.9). In six of eight patients whose cancer lesions could be assessed before corticosteroid therapy for AIP, abundant IgG4-positive plasma cell infiltration was observed in the cancer stroma. These six patients experienced no AIP relapse after successful cancer treatment. CONCLUSIONS: Patients with AIP are at high risk of having various cancers. The highest risk for cancer in the first year after AIP diagnosis and absence of AIP relapse after successful treatment of the coexisting cancers suggest that AIP may develop as a paraneoplastic syndrome in some patients.

[A case of endocrine carcinoma of the cecum treated with CDDP/VP-16].

A 41-year-old man was admitted to our hospital because of multiple liver tumors. Colonoscopy showed a mass lesion in the cecum. He was given a diagnosis of endocrine cell carcinoma by immunostaining technique, and received chemotherapy of CAPOX regimen for 3 courses. After that, he underwent second-line chemotherapy of EP(CDDP/VP-16)regimen due to deterioration of his performance status(PS), and his tumor marker NSE. He then showed dramatically improved PS, and improvement in the size of liver mets and NSE(4. 3mg/mL).

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.

Solitary pancreatic metastasis of occult pulmonary small cell carcinoma diagnosed by EUS-FNA cytology: a case report.

A 74-year-old man presented with symptoms suggestive of acute pancreatitis, and a mass lesion measuring 25 mm was detected in the pancreatic head. Cytological and histopathological examinations of EUS-FNA specimens taken from the lesion demonstrated small cell (neuroendocrine) carcinoma. Tumor cells were immunoreactive for cytokeratin, synaptophysin, chromogranin A, CD56, and TTF-1, and PET-CT of the chest revealed a small tumor in the upper lobe of the left lung. Pulmonary carcinoma, particularly small cell carcinoma, infrequently presents with a solitary metastatic lesion in the pancreas as an initial manifestation and clinically simulates a primary pancreatic neoplasm. Because primary small cell carcinoma of the pancreas is very uncommon, metastasis from the lung should always be considered when evaluating pancreatic neoplasms showing a "small cell" morphology. Immunohistochemistry for TTF-1 is useful for determining the pulmonary origin of this type of neoplasm, and its application to cytology specimens is recommended.

Mucinous Cystic Adenoma of the Liver: A Thought-Provoking Case of an Uncommon Hepatic Neoplasm.

BACKGROUND Mucinous cystic neoplasm (MCN) of the liver is a rare hepatic neoplasm: a cystic, mucus-producing tumor. Histopathologic examination reveals ovarian-like stroma. The origin of MCN of the liver is still unknown, although ectopic ovarian-like stroma in the liver has been suggested as a possibility. We document a thought-provoking case of MCN of the liver, and intratumoral fatty tissue may support the opinion that ectopic ovarian-like stroma in the liver is a possible origin for both MCN and ovarian teratoma. CASE REPORT An expansive 10.5-cm cystic tumor was incidentally detected in a 71-year-old woman. Imaging studies revealed that the tumor was multiloculated, with cyst contents comprising mucus, muddy-looking fluid (inspissated bile), and hematoma. Imaging studies revealed fatty tissue and calcifications in the cyst walls. The diagnosis of MCN of the liver was made, although MCNs have never been reported to include fatty tissue. Extended left lobectomy was performed, and the tumor was curatively removed without any rupture. A multilocular cyst, mucus, calcifications, and fatty tissue were clearly observed on gross inspection. Histopathological examination revealed ovarian-like stroma. Evidence of malignancy was not detected. Her postoperative course was uneventful. To the best of our knowledge, our patient is the first case of MCN of the liver with intratumoral fatty tissue. This case may support the hypothesis that MCN originates from ectopic ovarian-like stroma in the liver. CONCLUSIONS We documented a thought-provoking case of MCN of the liver in detail, and this MCN accompanied with fatty tissue might originate from ectopic ovarian-like stroma.

Adrenocorticotropic hormone-dependent hypercortisolism caused by pancreatic neuroendocrine carcinoma: A thought-provoking but remorseful case of delayed diagnosis.

INTRODUCTION AND IMPORTANCE: Definitive diagnosis of functioning neuroendocrine neoplasms (NENs) in the pancreas is challenging. Adrenocorticotropic hormone (ACTH) regulates adrenal cortisol production. Ectopic ACTH secretion by functioning NENs may cause hypercortisolism. PRESENTATION OF CASE: A 62-year-old woman who was receiving medications for hypertension and hyperlipidemia was referred to our hospital because of abnormal blood tests. Diabetes mellitus was initially diagnosed. Dynamic computed tomography and endoscopic ultrasound revealed a 35-mm diameter hypovascular tumor in the distal pancreas and multiple liver metastases. Endoscopic ultrasound-guided fine-needle aspiration resulted in a diagnosis of neuroendocrine carcinoma. The patient developed pancreatic leakage progressing to peritonitis, abscess formation, pleural effusion, and ascites after the fine-needle aspiration biopsy. Her clinical condition deteriorated to a septic state, necessitating emergency surgery comprising distal pancreatectomy, intraperitoneal lavage, and drainage. Wound healing was protracted and accompanied by ongoing high white blood cell counts and neutrophilia. She also developed a gastric ulcer postoperatively. Systematic endocrine investigations were performed because hypercortisolism caused by a functioning NEN was suspected. Eventually, a definitive diagnosis of an ACTH-producing NEN in the pancreas was made. Systemic chemotherapy was proposed; however, the patient and her family opted for palliative treatment only. She died 42 days after the initial diagnosis. CLINICAL DISCUSSION: We here present a patient with ACTH-dependent hypercortisolism attributable to a pancreatic NEN who died of progressive cancer after a delay in definitive diagnosis. CONCLUSION: Detailed investigation, including systematic endocrine examination and functional imaging studies, are important for precise diagnosis of, and appropriate treatment for, NENs.

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.

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.

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).

Impact of continuous local lavage on pancreatic juice-related postoperative complications: Three case reports.

BACKGROUND: Postoperative pancreatic leakage readily results in intractable pancreatic fistula and subsequent intraperitoneal abscess. This refractory complication can be fatal; therefore, intensive treatment is important. Continuous local lavage (CLL) has recently been reevaluated as effective treatment for severe infected pancreatitis, and we report three patients with postoperative intractable pancreatic fistula successfully treated by CLL. We also discuss our institutional protocol for CLL for postoperative pancreatic fistula. CASE SUMMARY: The first patient underwent subtotal stomach-preserving pancreaticoduodenectomy, and pancreatic leakage was observed postoperatively. Intractable pancreatic fistula led to intraperitoneal abscess, and CLL near the pancreaticojejunostomy site was instituted from postoperative day (POD) 8. The abscess resolved after 7 d of CLL. The second patient underwent distal pancreatectomy. Pancreatic leakage was observed, and intractable pancreatic fistula led to intraperitoneal abscess near the pancreatic stump. CLL was instituted from POD 9, and the abscess resolved after 4 d of CLL. The third patient underwent aneurysmectomy and splenectomy with wide exposure of the pancreatic parenchyma. Endoscopic retrograde pancreatic drainage was performed on POD 15 to treat pancreatic fistula; however, intraperitoneal abscess was detected on POD 59. We performed CLL endoscopically via the transgastric route because the percutaneous approach was difficult. CLL was instituted from POD 63, and the abscess resolved after 1 wk of CLL. CONCLUSION: CLL has therapeutic potential for postoperative pancreatic fistula.