Frequency of Obliteration of the Dorsal and Ventral Ducts of the Pancreas in Islet Transplantation.

BACKGROUND: Islet isolation is an essential process in every human islet transplantation protocol. Intraductal enzyme delivery followed by adequate distention of the pancreas is the most critical step in islet isolation. Anomalies of the pancreatic duct system can significantly affect this process. Thus, identification and characterization of ductal patency is of paramount importance to achieve optimal islet isolation. AIMS: To investigate the frequency of duct obliteration in the human pancreas and explore donor/patient characteristics associated with specific ductal variations. METHODS: We examined ductal patency of pancreata allocated for islet allotransplantation (n = 597) and autotransplantation (n = 21) after removal of the duodenum during islet isolation procedure. Donor/patient factors were reviewed from the batch files. RESULTS: Among 559 deceased donor pancreata without pancreas divisum (n = 38, 6.4%), both ducts were patent in 50.1%, only ventral duct was patent in 46.7%, and only dorsal duct was patent in 3.2%. Donor age was not associated with the frequency of obliterated dorsal duct. Black race tended to have the higher frequency of patent dorsal duct. As expected, pancreas divisum was more frequent in chronic pancreatitis cases (n = 6, 28.6%). Within 7 cases of chronic pancreatitis with unknown etiology, we encountered one case of ventral duct obliteration. CONCLUSIONS: The minor duodenal papilla and aging do not likely play an important role in the occurrence of dorsal duct obliteration. Although frequency of obliterated ventral duct was low in our population, physicians, including gastroenterologists and endoscopists, as well as islet transplantation researchers should be aware of this possibility.

Intraductal Transplantation Models of Human Pancreatic Ductal Adenocarcinoma Reveal Progressive Transition of Molecular Subtypes.

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal common malignancy, with little improvement in patient outcomes over the past decades. Recently, subtypes of pancreatic cancer with different prognoses have been elaborated; however, the inability to model these subtypes has precluded mechanistic investigation of their origins. Here, we present a xenotransplantation model of PDAC in which neoplasms originate from patient-derived organoids injected directly into murine pancreatic ducts. Our model enables distinction of the two main PDAC subtypes: intraepithelial neoplasms from this model progress in an indolent or invasive manner representing the classical or basal-like subtypes of PDAC, respectively. Parameters that influence PDAC subtype specification in this intraductal model include cell plasticity and hyperactivation of the RAS pathway. Finally, through intratumoral dissection and the direct manipulation of RAS gene dosage, we identify a suite of RAS-regulated secreted and membrane-bound proteins that may represent potential candidates for therapeutic intervention in patients with PDAC. SIGNIFICANCE: Accurate modeling of the molecular subtypes of pancreatic cancer is crucial to facilitate the generation of effective therapies. We report the development of an intraductal organoid transplantation model of pancreatic cancer that models the progressive switching of subtypes, and identify stochastic and RAS-driven mechanisms that determine subtype specification.See related commentary by Pickering and Morton, p. 1448.This article is highlighted in the In This Issue feature, p. 1426.

Human duct cells contribute to ß cell compensation in insulin resistance.

The identification of new sources of ß cells is an important endeavor with therapeutic implications for diabetes. Insulin resistance, in physiological states such as pregnancy or in pathological states such as type 2 diabetes (T2D), is characterized by a compensatory increase in ß cell mass. To explore the existence of a dynamic ß cell reserve, we superimposed pregnancy on the liver-specific insulin receptor-KO (LIRKO) model of insulin resistance that already exhibits ß cell hyperplasia and used lineage tracing to track the source of new ß cells. Although both control and LIRKO mice displayed increased ß cell mass in response to the relative insulin resistance of pregnancy, the further increase in mass in the latter supported a dynamic source that could be traced to pancreatic ducts. Two observations support the translational significance of these findings. First, NOD/SCID-γ LIRKO mice that became pregnant following cotransplantation of human islets and human ducts under the kidney capsule showed enhanced ß cell proliferation and an increase in ductal cells positive for transcription factors expressed during ß cell development. Second, we identified duct cells positive for immature ß cell markers in pancreas sections from pregnant humans and in individuals with T2D. Taken together, during increased insulin demand, ductal cells contribute to the compensatory ß cell pool by differentiation/neogenesis.

Stem cells to replace or regenerate the diabetic pancreas: Huge potential & existing hurdles.

Various stem cell sources are being explored to treat diabetes since the proof-of-concept for cell therapy was laid down by transplanting cadaveric islets as a part of Edmonton protocol in 2000. Human embryonic stem (hES) cells derived pancreatic progenitors have got US-FDA approval to be used in clinical trials to treat type 1 diabetes mellitus (T1DM). However, these progenitors more closely resemble their foetal counterparts and thus whether they will provide long-term regeneration of adult human pancreas remains to be demonstrated. In addition to lifestyle changes and administration of insulin sensitizers, regeneration of islets from endogenous pancreatic stem cells may benefit T2DM patients. The true identity of pancreatic stem cells, whether these exist or not, whether regeneration involves reduplication of existing islets or ductal epithelial cells transdifferentiate, remains a highly controversial area. We have recently demonstrated that a novel population of very small embryonic-like stem cells (VSELs) is involved during regeneration of adult mouse pancreas after partial-pancreatectomy. VSELs (pluripotent stem cells in adult organs) should be appreciated as an alternative for regenerative medicine as these are autologous (thus immune rejection issues do not exist) with no associated risk of teratoma formation. T2DM is a result of VSELs dysfunction with age and uncontrolled proliferation of VSELs possibly results in pancreatic cancer. Extensive brainstorming and financial support are required to exploit the potential of endogenous VSELs to regenerate the pancreas in a patient with diabetes.

Activin A, exendin-4, and glucose stimulate differentiation of human pancreatic ductal cells.

Islet transplantation is one treatment option for diabetes mellitus. However, novel sources of pancreatic islets or insulin-producing cells are required because the amount of donor tissue available is severely limited. Pancreatic ductal cells are an alternative source of ß-cells because they have the potential to differentiate into insulin-producing cells. We investigated whether treatment of human pancreatic ductal cells with activin A (ActA) and exendin-4 (EX-4) stimulated transdifferentiation of the cells, both in vitro and in vivo. We treated human pancreatic ductal cells with ActA and EX-4 in high-glucose media to induce differentiation into insulin-producing cells and transplanted the cells into streptozotocin-induced diabetic nude mice. Co-treatment of mice with ActA and EX-4 promoted cell proliferation, induced expression of pancreatic ß-cell-specific markers, and caused glucose-induced insulin secretion compared with the ActA or EX-4 mono-treatment groups respectively. When pancreatic ductal cells treated with ActA and EX-4 in high-glucose media were transplanted into diabetic nude mice, their blood glucose levels normalized and insulin was detected in the graft. These findings suggest that pancreatic ductal cells have a potential to replace pancreatic islets for the treatment of diabetes mellitus when the ductal cells are co-treated with ActA, EX-4, and glucose to promote their differentiation into functional insulin-producing cells.

Combination therapy with a dipeptidyl peptidase-4 inhibitor and a proton pump inhibitor induces ß-cell neogenesis from adult human pancreatic duct cells implanted in immunodeficient mice.

Combination therapy with a dipeptidyl peptidase-4 inhibitor (DPP-4i) and a proton pump inhibitor (PPI) raises endogenous levels of GLP-1 and gastrin, respectively, and restores pancreatic ß-cell mass and normoglycemia in nonobese diabetic (NOD) mice with autoimmune diabetes. The aim of this study was to determine whether a DPP-4i and PPI combination could increase ß-cell mass in the adult human pancreas. Pancreatic cells from adult human pancreas donors were implanted in NOD-severe combined immunodeficient (NOD-scid) mice and the mice were treated with a DPP-4i and a PPI for 16 weeks. Human grafts were examined for insulin content and insulin-stained cells. Graft ß-cell function was assessed by intravenous glucose tolerance tests (IVGTT) and by glucose control in human cell-engrafted mice treated with streptozotocin (STZ) to delete mouse pancreatic ß-cells. Plasma GLP-1 and gastrin levels were raised to two- to threefold in DPP-4i- and PPI-treated mice. Insulin content and insulin-stained cells in human pancreatic cell grafts were increased 9- to 13-fold in DPP-4i and PPI-treated mice and insulin-stained cells were colocalized with pancreatic exocrine duct cells. Plasma human C-peptide responses to IVGTT were significantly higher and STZ-induced hyperglycemia was more completely prevented in DPP-4i- and PPI-treated mice with grafts than in vehicle-treated mice with grafts. In conclusion, DPP-4i and PPI combination therapy raises endogenous levels of GLP-1 and gastrin and greatly expands the functional ß-cell mass in adult human pancreatic cells implanted in immunodeficient mice, largely from pancreatic duct cells. This suggests that a DPP-4i and PPI combination treatment may provide a pharmacologic therapy to correct the ß-cell deficit in type 1 diabetes.

Pancreas-preserving duodenal resections with bile and pancreatic duct replantation for duodenal dystrophy. Two case reports.

CONTEXT: Duodenal dystrophy is a rare disease, characterized by the chronic inflammation of the aberrant pancreatic tissue in the duodenal wall. CASE REPORTS: Two middle-aged men were admitted with upper abdominal pain of several months duration, periodic nausea and vomiting after meals, intermittent jaundice and weight loss. A diagnosis of cystic dystrophy of the vertical part of the duodenum without chronic inflammation of the orthotopic pancreas was established in both cases by multi-detector computed tomography, magnetic resonance imaging and endosonography. Both patients were successfully treated by two modifications of pancreas-preserving duodenal resections with reimplantation of the bile and pancreatic ducts into the neoduodenum. CONCLUSION: These cases are a good example of a pancreas-preserving approach to duodenal dystrophy treatment and can be an alternative to the Whipple procedure in cases of mild changes of the orthotopic gland.

Pancreatic duct cells in human islet cell preparations are a source of angiogenic cytokines interleukin-8 and vascular endothelial growth factor.

OBJECTIVE: Engraftment and function of human islet cell implants is considered to be dependent on their rapid and adequate revascularization. Studies with rodent islet grafts have shown that vascular endothelial growth factor (VEGF) expression by beta-cells can promote this process. The present work examines whether human islet preparations produce VEGF as well as interleukin (IL)-8, another angiogenic protein, and assesses the role of contaminating duct cells in VEGF and IL-8-mediated angiogenesis. RESEARCH DESIGN AND METHODS: Human islet and pancreatic duct cell preparations are compared for their respective expression and production of VEGF and IL-8 during culture as well as following transplantation in nonobese diabetic (NOD)/scid mice. The associated angiogenic effects are measured in an in vitro aortic ring assay and in an in vivo chick embryo chorioallantoic membrane assay. RESULTS: Cultured pancreatic duct cells expressed 3- and 10-fold more VEGF and IL-8, respectively, than cultured human islet endocrine cells and released both proteins at angiogenic levels. The angiogenic effect of purified duct cells was higher than that of purified endocrine islet cells and was completely blocked by a combination of IL-8 and VEGF antibodies. Human duct cell implants under the kidney capsule of NOD/scid mice expressed higher levels of IL-8 and VEGF than human islet cell implants and induced circulating IL-8 and VEGF levels during the first day posttransplantation. CONCLUSIONS: Human duct cell-released IL-8 and VEGF may help revascularization of currently used human islet cell grafts. Further work should examine whether and when this effect can prevail over other inflammatory and immune influences of this cell type.

Reversal of streptozotocin-induced hyperglycemia by transplantation of pseudoislets consisting of beta cells derived from ductal cells.

The present study was conducted in an attempt to treat streptozotocin (STZ)-induced hyperglycemia by transplanting beta cells derived from pancreatic ductal cells. Ductal cells obtained from neonatal rats were cultured in vitro. Approximately 70% of the cells were converted to insulin-secreting cells by incubating with betacellulin and activin A. Differentiated cells responded to a depolarizing concentration of potassium, tolbutamide and a high concentration of glucose, and insulin secretion increased by 2.5-, 2.3- and 1.6-fold, respectively. We then prepared pseudoislets using the differentiated cells, which exhibited greatly improved glucose-responsiveness, with a high concentration of glucose inducing a 3-fold increase in insulin secretion. We transplanted these pseudoislets into the portal vein of STZ-treated nude mice. Before transplantation, the plasma glucose concentration was above 400 mg/dl, and after transplantation it was markedly reduced, the effect of which persisted for two weeks. These results indicate that STZ-induced hyperglycemia can be treated by transplanting pseudoislets consisting of beta cells derived from ductal cells.

Formation of insulin-positive cells in implants of human pancreatic duct cell preparations from young donors.

AIMS/HYPOTHESIS: Pancreatic ducts are considered as potential sites for neogenesis of beta cells. In vitro studies have reported formation of islets from postnatal human and rodent duct tissue. We examined whether postnatal human duct-cell preparations can generate new beta cells after transplantation. METHODS: Pancreatic duct cells were prepared from the non-endocrine fraction of human donor pancreases that were processed for islet-cell isolation. Grafts containing 0.5 million duct cells with 1% contaminating insulin-positive cells were implanted under the kidney capsule of normoglycaemic nude mice. At 0.5 and 10 weeks post-transplantation, implants were examined for their cellular composition and for the volumes of their composing cell populations, i.e. cytokeratin 19-positive duct cells, synaptophysin-, insulin- and glucagon-positive endocrine cells. RESULTS: Between week 0.5 and 10, duct-cell volume decreased by at least 90% whereas the change in insulin-positive cell volume depended on donor age. Implants from donors over 10 years had a threefold decrease in their insulin-positive cell volume, while those from donors under 10 years had a 2.5-fold increase. After 10 weeks, the implants from the younger donors consisted of 19% insulin-positive cells occurring as single units or small cell clusters. Three percent of these insulin-positive cells also expressed the ductal marker CK 19 and were consistently found in conjunction with ductal epithelia; up to 1% was positive for the proliferation marker BrdU and located in small endocrine cell clusters. CONCLUSIONS/INTERPRETATION: These data indicate that duct cell preparations from donors under 10 years can generate insulin-positive cells. This process might involve differentiation of CK 19-positive-insulin cells that are formed at the duct epithelia as well as proliferation of insulin-positive cells within endocrine cell aggregates.

Experimental evidence for the origin of ductal-type adenocarcinoma from the islets of Langerhans.

To investigate the role of the islets of Langerhans in pancreatic carcinogenesis, freshly isolated islets from male Syrian hamsters were transplanted into the right submandibular glands of 50 female hamsters that were or were not pre-treated with streptozotocin. Thyroid gland fragments, cellulose powder, and immortal hamster pancreatic ductal cells were injected into the left submandibular gland of the same hamsters. All recipient hamsters were then treated with the potent pancreatic carcinogen N-nitrosobis(2-oxopropyl)amine weekly at a dose of 40 mg/kg of body weight for 3 weeks. Between 3 and 8 weeks later, 18 of 75 (24%) hamsters developed large ductal-type adenocarcinomas in the submandibular gland region, where islets were transplanted, but none developed tumors in the left submandibular gland. In 9 of 18 hamsters, tumors were multiple so that a total of 31 cancers were found. Eleven of these carcinomas were in the vicinity of transplanted islets, eight of which showed intra-insular ductular or cyst formation as seen in the pancreas of hamsters during pancreatic carcinogenesis. The formation of ductular structures within islets was also demonstrated in vitro. Some tumor cells in the vicinity of these islets were reactive with anti-insulin. Y chromosome message was found by polymerase chain reaction analysis in one of the three tumors examined. Also, like the induced pancreatic tumors, all three submandibular gland tumors that were examined had the mutation of the c-Ki-ras oncogene at codon 12 and all tumors expressed blood group A antigen. These and other findings strongly suggest that some components of islets, most probably stem cells, are the origin of ductal-type adenocarcinomas in this model.

Histological features of acute pancreatic allograft rejection after pancreaticoduodenal transplantation in the rat.

For characterization of histopathological changes during pancreas graft rejection, pancreaticoduodenal transplants were performed in three groups: (1) Brown Norway into diabetic Lewis rats without immunosuppression, (2) Brown Norway into diabetic Lewis rats with cyclosporin A, and (3) Lewis into Lewis rats. Diffuse inflammatory infiltration of the acini by mononuclear cells indicated the onset of rejection (stage I). Shortly after acinar infiltration, damage to small and large interlobular excretion ducts occurred. This took the form of florid circumferential inflammation and vacuolar degeneration of epithelium similar to the bile duct damage seen in primary biliary cirrhosis, graft-versus-host disease, and liver allograft rejection (stage II). Thereafter, endothelialitis and destruction of islets were evident, consistent with a more advanced and irreversible stage of rejection (stage III). Acinar inflammation and moderate duct lesions were not prevented by immunosuppression but were delayed. Nonetheless, severe vascular changes and loss of islets were avoided. We conclude that duct lesions are a reliable criterion for pancreas allograft rejection. They are more sensitive than vascular changes and more specific than cellular infiltration of acinar tissue, which may also occur in infection.

[The motor activity of the stomach after the distal transposition of the pancreatic duct]. / Motornaia deiatel'nost' zheludka posle distal'noi transpozitsii protoka podzheludochnoi zhelezy.

The stomach motility was quantitatively characterised during evacuation of acid and bicarbonate solution prior to and within 3 months after transposition of the pancreatic duct into the jejunum in dogs with fistulae. Pancreatic secret seems to play a major part in the systemic regulation of gastro-duodenal complex activity.

[The effect of distal transposition of the pancreatic duct on gastric motility]. / Vliianie distal'noi transpozitsii pankreaticheskogo protoka na motoriku zheludka.

The stomach motor activity activated by mashed meat and bread prior to and within 3 months after transposition of main pancreatic duct into the proximal portion of the jejunum, was studied in dogs with fistulae. The distal transposition of the pancreatic duct was found to reduce significantly the rate of the stomach contractions, to increase its tonus in later period and to be able to reduce the strength of the stomach contractions in delayed hours after feeding. The duodenal mechanisms of the regulation of the stomach motility were transformed in conditions of a distal shift of the pancreatic secret inflow into the intestine.