Current status of total pancreatectomy with islet autotransplantation for chronic and recurrent acute pancreatitis.

Total pancreatectomy with islet autotransplantation (TPIAT) is an established and effective treatment modality for patients diagnosed with intractable chronic pancreatitis (CP) and recurrent acute pancreatitis (RAP). TPIAT primarily aims to manage debilitating pain leading to impaired quality of life among patients with CP or RAP, which can be successfully managed with medical, endoscopic, or surgical interventions. TPIAT is significantly successful in relieving pain associated with CP and improving health-related quality of life outcomes. Furthermore, the complete loss of pancreatic endocrine function attributed to total pancreatectomy (TP) can be compensated by autologous islet transplantation (IAT). Patients receiving IAT can achieve insulin independence or can be less dependent on exogenous insulin compared with those receiving TP alone. Historically, TPIAT has been mainly used in the United States, and its outcomes have been improving due to technological advancements. Despite some challenges, TPIAT can be a promising treatment for patients with CP-related intractable pain. Thus far, TPIAT is not commonly performed in Japan. Nevertheless, it may improve health-related quality of life in Japanese patients with CP, similar to Western patients. This review article aimed to provide an overview of the indications, related procedures, and outcomes of TPIAT and to discuss future prospects in Japan.

Impact of Prevascularization on Immunological Environment and Early Engraftment in Subcutaneous Islet Transplantation.

BACKGROUND: The utilization of islet-like cells derived from pluripotent stem cells may resolve the scarcity of islet transplantation donors. The subcutaneous space is a promising transplantation site because of its capacity for graft observation and removal, thereby ensuring safety. To guarantee subcutaneous islet transplantation, physicians should ensure ample blood supply. Numerous methodologies, including prevascularization, have been investigated to augment blood flow, but the optimal approach remains undetermined. METHODS: From C57BL/6 mice, 500 syngeneic islets were transplanted into the prevascularized subcutaneous site of recipient mice by implanting agarose rods with basic fibroblast growth factor at 1 and 2 wk. Before transplantation, the blood glucose levels, cell infiltration, and cytokine levels at the transplant site were evaluated. Furthermore, we examined the impact of the extracellular matrix capsule on graft function and the inflammatory response. RESULTS: Compared with the 1-wk group, the 2-wk group exhibited improved glycemic control, indicating that longer prevascularization enhanced transplant success. Flow cytometry analysis detected immune cells, such as neutrophils and macrophages, in the extracellular matrix capsules, whereas cytometric bead array analysis indicated the release of inflammatory and proinflammatory cytokines. Treatment with antitumor necrosis factor and anti-interleukin-6R antibodies in the 1-wk group improved graft survival, similar to the 2-wk group. CONCLUSIONS: In early prevascularization before subcutaneous transplantation, neutrophil and macrophage accumulation prevented early engraftment owing to inflammatory cytokine production.

Acinar cystic transformation in the pancreatic tail.

Pancreatic acinar cystic transformation (ACT) is a rare non-neoplastic cystic lesion that is predominantly located at the pancreatic head in females. Preoperative definitive diagnosis of ACT remains challenging despite advances in radiologic imaging methods. A 25-year-old male patient presented with abdominal discomfort and a 50-mm cystic lesion in the pancreatic tail. The patient underwent laparoscopic distal pancreatectomy, because branch duct intraductal papillary mucinous neoplasm cannot be ruled out and the presence of abdominal symptoms. The resected specimen revealed a collection of small and large cysts lined by a single cuboidal epithelium layer with scattered pancreatic tissue exhibiting fibrosis in the septal wall. The cystic lesion was epithelial, trypsin-positive, B cell lymphoma 10-positive, cytokeratin 19-positive, mucin 1-positive, and MUC6-negative with a differentiated lobular central conduit causing to an adeno-cystic cell, thereby supporting the ACT diagnosis. Distinguishing ACT from other pancreatic cystic tumors remains a diagnostic challenge despite improvements in radiologic imaging methods. Surgical resection may be justified when other cystic neoplasms cannot be excluded because of its heterogeneous nature, although the ACT is a non-neoplastic lesion, and cases of malignant transformation have never been reported to date.

Preoperative Endoscopic Minor Papilla Sphincterotomy for Pancreas Divisum in a Patient with Pancreatic Cancer Who Underwent Laparoscopic Distal Pancreatectomy.

BACKGROUND: Pancreas divisum (PD) is a congenital anomaly that occurs due to failure of fusion of the dorsal and ventral pancreatic ductal systems.1-3 In PD, pancreatic juice drains mainly through the minor papilla via the dorsal duct, leading to high intraductal pressure, which can cause pancreatitis.1-3 We report a case of PD that underwent preoperative decompression using endoscopic minor papilla sphincterotomy (EMPS) before laparoscopic distal pancreatectomy (LDP) for pancreatic cancer.3 METHODS: The patient was a 74-year-old woman with pancreatic tail cancer, measuring 35 mm in size, in PD with an entirely dilated dorsal duct, implying high, intraductal pressure caused by minor papillary dysfunction. We performed EMPS to prevent postoperative pancreatitis and pancreatic fistula before LDP using a left-posterior approach, as previously described.4 As the pancreatic transection margin was positive for high-grade pancreatic intraepithelial neoplasia on intraoperative pathology, an additional resection of the pancreatic head to the right side of the portal vein was performed after the liberation of the gastroduodenal artery with both the dorsal and ventral pancreatic ducts ligated and divided. RESULTS: The operative time was 421 min, and blood loss was 70 mL. The postoperative course was uneventful, with no evidence of pancreatitis or pancreatic fistula. The patient was discharged on postoperative Day 10. Postoperative computed tomography revealed reduced dilatation of the dorsal duct. CONCLUSIONS: Preoperative EMPS may be effective in preventing pancreatic fistula after LDP in patients with PD.

Comparison of Oncological and Perioperative Outcomes Between Self-Expanding Metal Stents and Decompression Tubes for Stages II and III Obstructive Colorectal Cancer: A Retrospective Observational Study.

BACKGROUND: A bridge to surgery (BTS) using self-expandable metallic stents (SEMSs) is becoming the primary treatment for obstructive colorectal cancer (OCRC). In Japan, intestinal decompression was usually performed using decompression tubes (DTs). However, few reports have compared the outcomes of SEMS and DTs as BTS. Therefore, we compared the treatment outcomes of SEMS and DTs for OCRC. METHODS: Data of 80 patients who underwent radical resection after endoscopic decompression for stage II or III OCRC between 2007 and 2021 were retrospectively analyzed. Patients were divided into two groups based on whether they received SEMS (n = 53) or DTs (n = 27). RESULTS: The clinical success rate of decompression was 96.2% and 88.9% in the SEMS and DT groups, respectively. Additionally, 96.2% of patients who received SEMS were able to resume their routine diet without stricture symptoms. The rate of stoma construction and incidence of postoperative complications were lower in the SEMS group (p < 0.005 and p < 0.01, respectively). The 3-year relapse-free survival rates were 71.9% and 51.2% in the SEMS and DT groups, respectively, which were not significantly different (p = 0.10). CONCLUSION: BTS using SEMS might be an adequate treatment for stage II or III OCRC regardless of tumor location owing to the comparable oncological outcomes with DT and low perioperative complication rate.

Eosinophilic peritonitis with colon cancer: a case report.

BACKGROUND: Eosinophilic gastrointestinal disorders (EGIDs) are a rare group of inflammatory disorders that can occur anywhere along the gastrointestinal tract, from the esophagus to the rectum. In particular, those with malignant or benign tumors are extremely rare. CASE PRESENTATION: A 62-year-old man was referred to our hospital with a chief complaint of abdominal fullness. The peripheral white blood cell count was 19,400/µL, and the eosinophil count was 13,300/µL. Abdominal computed tomography showed massive ascites. Cytology of the ascitic fluid showed a large amount of eosinophils and no malignancy. Upper and lower gastrointestinal endoscopies were performed on the suspicion of EGIDs, and colon cancer with no other abnormalities was found. The biopsies of the cancer lesions and non-cancer lesions also showed significant differences in eosinophil counts per high-power field (HPF) between the cancer and non-cancer lesions (median 77.5 [IQR 52-115] vs. 40.5 [35-56]/HPF, P < 0.05). Exploratory laparoscopy showed cloudy massive ascites and thickening of the mesentery. Pathological examination of the mesentery showed a large amount of eosinophils (median 177.5 [IQR 91-227]/HPF) and no malignancy. Based on these findings, it was suspected that the massive ascites due to eosinophilic peritonitis could be associated with colon cancer. Steroid administration resulted in immediate disappearance of the ascites, and laparoscopic left hemicolectomy was safely performed 6 weeks after steroid administration. CONCLUSION: This report presented a case of eosinophilic peritonitis that could be related to colon cancer. Exploratory laparoscopy was useful to detect the cause of ascites. The possibility that eosinophilic peritonitis was associated with colon cancer is discussed based on the histopathological findings.

The MEK Inhibitor Trametinib Suppresses Major Histocompatibility Antigen-mismatched Rejection Following Pancreatic Islet Transplantation.

BACKGROUND: Potential adverse effects, such as functional impairment of islets, render conventional immunosuppressive drugs unsuitable for use in islet transplantation. In addition, as a single therapy, they cannot prolong islet allograft survival. Here, we investigated the utility of the mitogen-activated protein kinase inhibitor trametinib and asked whether it ameliorates acute rejection of transplanted islets without the need for conventional immunosuppressants. METHODS: Islets from fully major histocompatibility complex-mismatched BALB/c mice were transplanted into streptozotocin-induced diabetic C57BL/6 mice via the portal vein. These mice received trametinib or vehicle (orally) for 28 days. Isolated islets from BALB/c mice were incubated in vitro with different concentrations of trametinib to determine viability and function. RESULTS: Trametinib (0.1 and 0.3 mg/kg) prolonged graft survival significantly (P = 0.0007 and P = 0.005, respectively) when compared with vehicle. Histologic analyses revealed that cellular infiltration of the graft by lymphocytes was inhibited significantly on day 7 (P < 0.05). In addition, trametinib suppressed functional differentiation of naive CD4+ T cells in recipients. Expression of mRNA encoding inflammatory cytokines interleukin (IL)-2, tumor necrosis factor α, and interferon γ in recipients treated with trametinib was also inhibited (P < 0.001, P < 0.05, and P < 0.01, respectively). Trametinib also increased production of IL-4 and IL-10 (P < 0.05 and P = 0.20, respectively). In vitro, islets incubated with different concentrations of trametinib exhibited no harmful effects with respect to viability and function. CONCLUSIONS: Trametinib delayed islet graft rejection by inhibiting functional differentiation of naive CD4+ T cells and regulating inflammatory cytokines. Trametinib might be a promising candidate for maintenance immunosuppressive therapy after allogeneic islet transplantation.

Mitomycin C treatment improves pancreatic islet graft longevity in intraportal islet transplantation by suppressing proinflammatory response.

The in vitro culture period prior to cell transplantation (i.e. pancreatic islet transplantation) enables cell modification and is thus advantageous. However, the islet preconditioning method has not been fully explored. Here we present a simple approach for islet preconditioning that uses the antibiotic mitomycin C (MMC), which has antitumor activity, to reduce islet immunogenicity and prevent proinflammatory events in an intraportal islet transplantation model. Freshly isolated mice islets were treated for 30 min with 10 µg/mL MMC or not, cultured for 20 h and transplanted into the livers of syngeneic or allogeneic diabetic mouse recipients. In the allogeneic model, MMC preconditioning significantly prolonged graft survival without requiring immunosuppressants. In vitro, MMC treatment suppressed the expression of proinflammatory cytokines in islet allografts, while immunohistochemical studies revealed the suppression of inflammatory cell infiltration into MMC-treated allografts relative to untreated allografts. Furthermore, MMC preconditioning significantly suppressed the mRNA expression of proinflammatory cytokines into the transplant site and induced the differentiation of regulatory T cells with the ability to suppress CD4+ T cell-mediated immune responses. In conclusion, islet preconditioning with MMC prolonged graft survival in an intraportal islet transplantation model by suppressing proinflammatory events and inducing potentially regulatory lymphocytes.

Compact fluidic system for functional assessment of pancreatic islets.

Transplantation of pancreatic islets is becoming a promising therapy for people with type I diabetes. In this study, we present a compact fluidic system that enables assessment of islet functionality ex vivo for efficient islet transplantation. The fluidic system includes a micromesh sheet-embedded chip. Islets can be loaded easily on the micromesh sheet and observed clearly by microscopy. Islets on the mesh sheet mainly remained in place during perfusion and did not get damaged by hydraulic pressure because of high porosity of the micromesh sheet. The fluidic system was assembled with a sample fraction chip of polydimethylsiloxane. The chip includes a channel and columns, both having surfaces that were super-hydrophilized so that solutions could flow smoothly within the chip by gravity. Using mouse pancreatic islets, a dynamic glucose-stimulated insulin secretion test was performed to examine the performance of the fluidic system. The system successfully analyzed levels and patterns of insulin secretion upon exposure of the islets to low- and high-glucose solutions in turns, thus demonstrating its capacity to assess islet functions more easily and cost-effectively.