Intraportal Pancreatic Islet Transplantation Research Articles

2022 Canadian Surgery Forum Sept. 15–17, 202201. Operative classification of ventral abdominal hernias: new and practical classification02. Watchful waiting for large primary splenic cysts03. Transversus abdominis plane (TAP) blocks with and without dexamethasone in colorectal surgery04. What factors determine publication of resident research day projects?05. Characterization of near-infrared imaging and indocyanine green use amongst general surgeons06. Variation in opioid prescribing

# 01. Operative classification of ventral abdominal hernias: new and practical classification {#article-title-2} Ventral hernias of the abdomen are defined as a noninguinal, nonhiatal defect in the fascia of the abdominal wall. Unfortunately, there is not currently a universal classification system

Outcomes Following Extrahepatic and Intraportal Pancreatic Islet Transplantation: A Comparative Cohort Study.

Preliminary studies show promise for extrahepatic islet transplantation (ITx). However, clinical comparisons with intraportal ITx outcomes remain limited. This single-center cohort study evaluates patients receiving extrahepatic or intraportal ITx between 1999 and 2018. Primary outcome was stimulated C-peptide level. Secondary outcomes were fasting plasma glucose, BETA-2 scores, and fasting C-peptide level. Multivariable logistic modeling evaluated factors independently associated with a composite variable of early graft failure and primary nonfunction within 60 d of ITx. Of 264 patients, 9 (3.5%) received extrahepatic ITx (gastric submucosal = 2, subcutaneous = 3, omental = 4). Group demographics were similar at baseline (age, body mass index, diabetes duration, and glycemic control). At 1-3 mo post-first infusion, patients receiving extrahepatic ITx had significantly lower stimulated C-peptide (0.05 nmol/L versus 1.2 nmol/L, P < 0.001), higher fasting plasma glucose (9.3 mmol/L versus 7.3 mmol/L, P < 0.001), and lower BETA-2 scores (0 versus 11.6, P < 0.001) and SUITO indices (1.5 versus 39.6, P < 0.001) compared with those receiving intraportal ITx. Subjects receiving extrahepatic grafts failed to produce median C-peptide ≥0.2 nmol/L within the first 60 d after transplant. Subsequent intraportal infusion following extrahepatic transplants achieved equivalent outcomes compared with patients receiving intraportal transplant alone. Extrahepatic ITx was independently associated with early graft failure/primary non-function (odds ratio 1.709, confidence interval 73.8-39 616.0, P < 0.001), whereas no other factors were independently predictive. Using current techniques, intraportal islet infusion remains the gold standard for clinical ITx, with superior engraftment, graft function, and glycemic outcomes compared with extrahepatic transplantation of human islets.

P.101: Safety and Efficacy of a Percutaneous Intraportal Islet Transplantation Procedure Using Tract Embolization With Gelatine Foam Pledgets

Introduction: Intraportal pancreatic islet transplantation is a minimally invasive procedure to treat patients with diabetes mellitus and unstable glycemic control despite optimal medical treatment. We analysed the safety and efficacy of percutaneous transhepatic intraportal islet transplantation procedures using embolization of the hepatic puncture tract with gelatin foam pledgets. Methods: This was a retrospective, single center study including all allogeneic islet transplantations between 2007 and 2019 at the Leiden University Medical Center. Under local anaesthesia, islets were infused into the main portal vein using a right-sided transhepatic approach. Tract embolization was performed in 51/62 procedures using the Hunter Biopsy Sealing Device. Complications were assessed according to CTCAEv5.0. Stimulated C-peptide during a mixed meal test was measured after 3 months to evaluate efficacy. Results: A total of 62 islet transplants in 38 recipients (female 39.5%; median age 53.2 (IQR 40.8 – 64.0) years) were included. 11 complications occurred in 62 procedures: no CTCAE grade 4 or 5 complications occurred. Bleeding occurred in 3/11 (27.3%) of procedures without tract embolization, compared to 2/51 (3.9%) with tract embolization (p=0.01). 3 of these bleeding episodes comprised grade 3 complications which could be managed conservatively, and 2 bleeding episodes were grade 1 that did not require intervention. More than one puncture attempt was a positive predictor for bleeding (p=0.001) and pain (p=0.002). No portal vein thromboses were encountered.1 biliary puncture (grade 1) and 5 episodes of pain (grade 1 (n=3) and grade 2 (n=2)) occurred. Three months after infusion, stimulated C-peptide was >0.17 nmol/L in 60/62 (97%) transplant recipients. Conclusion: A percutaneous transhepatic procedure using gelatine foam pledgets is a safe and efficacious method to transplant islets into the portal vein. Complications were either self-limiting or could be managed with non-invasive treatment. The vast majority of patients gained endogenous insulin production.

Cibinetide Protects Isolated Human Islets in a Stressful Environment and Improves Engraftment in the Perspective of Intra Portal Islet Transplantation

During intra-portal pancreatic islet transplantation (PITx), innate immune reactions such as the instant blood mediated inflammatory reaction (IBMIR) cause an immediate loss of islets. The non-hematopoietic erythropoietin analogue cibinetide has previously shown islet-protective effects in mouse PITx. Herein, we aimed to confirm cibinetide’s efficacy on human islets, and to characterize its effect on IBMIR. We cultured human islets with pro-inflammatory cytokines for 18 hours with or without cibinetide. ATP content and caspase 3/7 activity were measured. Dynamic glucose perfusion assay was used to evaluate islet function. To evaluate cibinetides effect on IBMIR, human islets were incubated in heparinized polyvinyl chloride tubing system with ABO compatible blood and rotated for 60 minutes to mimic the portal vein system. Moreover, human islets were transplanted into athymic mice livers via the portal vein with or without perioperative cibinetide treatment. The mice were sacrificed six days following transplantation and the livers were analyzed for human insulin and serum for human C-peptide levels. Histological examination of recipient livers to evaluate islet graft infiltration by CD11b+ cells was performed. Our results show that cibinetide maintained human islet ATP levels and reduced the caspase 3/7 activity during culture with pro-inflammatory cytokines and improved their insulin secreting capacity. In the PVC loop system, administration of cibinetide reduced the IBMIR-induced platelet consumption. In human islet to athymic mice PITx, cibinetide treatment showed an increased amount of human insulin in the livers and higher serum human C-peptide, while histological examination of the livers showed reduced infiltration of pro-inflammatory CD11b+ cells around islets grafts compared to the controls. In summary, Cibinetide protected isolated human islets in a pro-inflammatory milieu and reduced IBMIR related platelet consumption. It improved engraftment of human islets in athymic mice. The study confirms that cibinetide is a promising agent to be used in clinical PITx.

Improvement of Islet Allograft Function Using Cibinetide, an Innate Repair Receptor Ligand.

During intraportal pancreatic islet transplantation (PITx), early inflammatory reactions cause an immediate loss of more than half of the transplanted graft and potentiate subsequent allograft rejection. Previous findings suggest that cibinetide, a selective innate repair receptor agonist, exerts islet protective and antiinflammatory properties and improved transplant efficacy in syngeneic mouse PITx model. In a stepwise approach toward a clinical application, we have here investigated the short- and long-term effects of cibinetide in an allogeneic mouse PITx model. Streptozotocin-induced diabetic C57BL/6N (H-2) mice were transplanted with 320 (marginal) or 450 (standard) islets from BALB/c (H-2) mice via the portal vein. Recipients were treated perioperative and thereafter daily during 14 d with cibinetide (120 µg/kg), with or without tacrolimus injection (0.4 mg/kg/d) during days 4-14 after transplantation. Graft function was assessed using nonfasting glucose measurements. Relative gene expressions of proinflammatory cytokines and proinsulin of the graft-bearing liver were assessed by quantitative polymerase chain reaction. Cibinetide's effects on dendritic cell maturation were investigated in vitro. Cibinetide ameliorated the local inflammatory responses in the liver and improved glycemic control immediately after allogeneic PITx and significantly delayed the onset of allograft loss. Combination treatment with cibinetide and low-dose tacrolimus significantly improved long-term graft survival following allogeneic PITx. In vitro experiments indicated that cibinetide lowered bone-marrow-derived-immature-dendritic cell maturation and subsequently reduced allogeneic T-cell response. Cibinetide reduced the initial transplantation-related severe inflammation and delayed the subsequent alloreactivity. Cibinetide, in combination with low-dose tacrolimus, could significantly improve long-term graft survival in allogeneic PITx.

Intraportal Transplantation of Pancreatic Islets in Mouse Model.

Pancreatic islet transplantation to reduce hyperglycemia is highly successful in rodents with chemically-induced diabetes. The most common transplantation site in experimental islet transplantation is the kidney capsule. However, as less is known about the interaction of pancreatic islets with blood constituents, it also makes sense to utilize the portal vein approach in experimental islet transplantation. This protocol demonstrates an intraportal islet transplantation technique in NMRI nude mice. Streptozotocin (180 mg/kg) is injected intraperitoneally to induce hyperglycemia in recipient mice. They are considered as diabetic at a non-fasting blood glucose level greater than 20 mmol/L. One day prior to transplantation, mouse pancreatic islets are isolated from the donor pancreas by collagenase digestion; a minimum of 350 islets are utilized per diabetic recipient. Depending upon the islet isolation yield, two or more donor mice are utilized per recipient. After overnight culture at 37 °C, islets are administered into the recipient liver via the portal vein. After surgery, the mice are protected in red Makrolon houses and observed until are awake. This protocol maintains glycemic control for 120 days in syngeneic mice and 15 days in allogeneic mice.

Intraportal Transplantation of Pancreatic Islets in Mouse Model

Intraportal Transplantation of Pancreatic Islets in Mouse Model

Polymeric nano-shielded islets with heparin-polyethylene glycol in a non-human primate model

Intraportal pancreatic islet transplantation incurs huge cell losses during its early stages due to instant blood-mediated inflammatory reactions (IBMIRs), which may also drive regulation of the adaptive immune system. Therefore, a method that evades IBMIR will improve clinical islet transplantation. We used a layer-by-layer approach to shield non-human primate (NHP) islets with polyethylene glycol (nano-shielded islets, NSIs) and polyethylene glycol plus heparin (heparin nano-shielded islets; HNSIs). Islets ranging from 10,000 to 20,000 IEQ/kg body weight were transplanted into 19 cynomolgus monkeys (n = 4, control; n = 5, NSI; and n = 10, HNSI). The mean C-peptide positive graft survival times were 68.5, 64 and 108 days for the control, NSI and HNSI groups, respectively (P = 0.012). HNSI also reduced the factors responsible for IBMIR in vitro. Based on these data, HNSIs in conjunction with clinically established immunosuppressive drug regimens will result in superior outcomes compared to those achieved with the current protocol for clinical islet transplantation.

Allo- and auto-percutaneous intra-portal pancreatic islet transplantation (PIPIT) for diabetes cure and prevention: the role of imaging and interventional radiology.

Although the life expectancy of patients with type 1 diabetes mellitus (T1DM) has improved since the introduction of insulin therapy, the acute life-threatening and long-term complications from diabetes mellitus are significant causes of both mortality and morbidity. Percutaneous intra-portal pancreatic islet transplantation (PIPIT) is a minimally invasive, repeatable procedure which allows a β-cell replacement therapy through a liver islet engraftment, leading to insulin release and glycaemic control restoration in patients with diabetes. Allo-PIPIT, in which isolated and purified islets from cadaveric donor are used, does not require major surgery, and is potentially less expensive for the recipient. In case of long-term T1DM, islet-after-kidney (IAK) transplantation can simultaneously cure diabetes and chronic renal failure, while islet-transplant-alone (ITA) is performed in brittle, short-term T1DM, based on the infusion of an adequate islet mass and on a steroid-free immunosuppressive regimen according to the Edmonton protocol. Results of the Collaborative Islet Transplant Registry (CITR) demonstrate that allo-PIPIT reduces episodes of hypoglycemia and diabetic complications, and improves quality of life of diabetic patients. Auto-PIPIT, in which the own patient's islets are used, has been investigated as a preventive treatment for pancreatogenic diabetes in patients who undergo extensive pancreatectomy for malignant and non-malignant disease. This Review outlines the role of imaging and interventional radiology in allo- and auto-PIPIT.

Hepatocellular clear cell foci after combined intraportal pancreatic islet transplantation and knockout of chREBP in diabetic mice

Hepatocellular clear cell foci after combined intraportal pancreatic islet transplantation and knockout of chREBP in diabetic mice

Hepatocellular glycogenotic foci after combined intraportal pancreatic islet transplantation and knockout of the carbohydrate responsive element binding protein in diabetic mice

AimsThe intraportal pancreatic islet transplantation (IPIT) model of diabetic rats is an insulin mediated model of hepatocarcinogenesis characterized by the induction of clear cell foci (CCF) of altered hepatocytes, which are pre-neoplastic lesions excessively storing glycogen (glycogenosis) and exhibiting activation of the AKT/mTOR protooncogenic pathway. In this study, we transferred the IPIT model to the mouse and combined it with the knockout of the transcription factor carbohydrate responsive element binding protein (chREBP).MethodsC57BL/6J Wild-type (WT) and chREBP-knockout (chREBP-KO) mice (n = 297) were matched to 16 groups (WT/ chREBP-KO, experimental/control, streptozotocine-induced diabetic/not diabetic, one/four weeks). Experimental groups received the intraportal transplantation of 70 pancreatic islets. Liver and pancreatic tissue was examined using histology, morphometry, enzyme- and immunohistochemistry and electron microscopy.ResultsCCF emerged in the liver acini downstream of the transplanted islets. In comparison to WT lesions, CCF of chREBP-KO mice displayed more glycogen accumulation, reduced activity of the gluconeogenic enzyme glucose-6-phosphatase, decreased glycolysis, lipogenesis and reduced levels of the AKT/mTOR cascade members. Proliferative activity of CCF was ∼two folds higher in WT mice than in chREBP-KO mice.ConclusionsThe IPIT model is applicable to mice, as murine CCF resemble preneoplastic liver lesions from this hepatocarcinogenesis model in the rat in terms of morphological, metabolic and molecular alterations and proliferative activity, which is diminished after chREBP knockout. chREBP appears to be an essential component of AKT/mTOR mediated cell proliferation and the metabolic switch from a glycogenotic to lipogenic phenotype in precursor lesions of hepatocarcinogenesis.

Highly Selective Intraportal Transplantation of Pancreatic Islets

Histological assessment of intraportally transplanted islets in experimental rodent models is limited by the wide dissemination of islets throughout the liver. We describe a technique of highly selective intraportal islet transplantation, which increases the density of transplanted islets and hence facilitates their histological analysis and validate this model as a means of quantitative histological analysis of islet graft survival. We also compared the number of islets visualized histologically with that of nonabsorbable dextran beads, representing the number of transplanted islets there would have been if there had been no graft loss. Diabetic Lewis rats or nondiabetic Sprague-Dawley rats were transplanted with 500 or 1000 syngeneic islets or an equivalent number of beads either into the main branch (MB), or selectively into the right branch (RB) of the portal vein. Islet transplantation led to an identical fall in blood glucose levels whichever technique was used. The graft area and number of islets recovered for histological analysis was 3- to 4-fold higher when islets were transplanted using the RB technique. Quantitative histological graft analysis demonstrated that 46% to 61% of intraportally transplanted islets were lost compared with corresponding bead graft sizes. Fewer islets were lost when a greater islet mass was transplanted. Selective islet transplantation increases the concentration of islets and hence facilitates islet recovery after intraportal transplantation without detrimental effects on transplantation outcome. This technique, when combined with bead transplantation and digital image analysis, provides an accurate method for estimating the number of islets surviving intra-portal transplantation.

Revelation of simple and complex liver acini after portal transplantation of pancreatic islets or thyroid follicles in rats

The microarchitecture of the liver is still not completely understood although various concepts of structural liver organization have been proposed. Among them, Rappaport's liver acinus stands out as one of the most accepted models. The correctness of this model, however, has also been doubted, and its applicability is hampered by the fact that the outlines of the liver acinus are disguised and nobody was ever able to give visual evidence by "unmasking" a simple liver acinus from the surrounding liver tissue. After intraportal transplantation of pancreatic islets or thyroid follicles into diabetic or thyroidectomized rats, respectively, the transplants engraft in small portal tracts and morphologically alter the downstream liver tissue due to excessive hormone secretion. Using a combined approach of perfusion fixation, stereomicroscopy, and light microscopy, we demonstrate in this study that these foci of altered liver tissue represent simple and complex liver acini, exactly as described by Rappaport. We present stereomicroscopical and histological examples of all important cut levels of altered simple and complex liver acini, including their topographical relation to the supplying and draining vessels and to the "central vein" liver lobule. Moreover, by computer-aided reconstruction of serial semi-thin sections, we were able to present the first 3-dimensional images of simple and complex liver acini. Our results prove the correctness of Rappaport's acinus model and confirm the simple liver acinus as the principal microcirculatory unit of the liver.

Radiologic aspects of islet cell transplantation

Percutaneous transhepatic intraportal pancreatic islet transplantation is an experimental treatment for patients with type 1 diabetes. The radiologic aspects of pancreatic islet transplantation are described, including a review of interventional radiology, ultrasound, and fluoroscopy image-guided, minimally invasive techniques and procedure-related complications and their avoidance.

Effect of Inspired Oxygen on Portal and Hepatic Oxygenation: Effective Arterialization of Portal Blood by Hyperoxia

Because hypoxia may compromise the survival of intraportally transplanted pancreatic islets, we have measured portal blood flow and both portal and hepatic oxygenation in normal and diabetic rats breathing graded inspired oxygen concentrations. Portal blood flow and hepatic tissue oxygenation were measured using a transonic flowmeter and near infrared spectroscopy while gas analysis was carried out on portal venous blood samples. The effects of breathing 13%, 21%, 50%, or 100% oxygen were compared in animals with steptozotocin-induced diabetes and in controls. In diabetic rats breathing 21% oxygen, portal blood flow was significantly lower than in controls (7.2+/-0.7 vs. 9.1+/-0.8 ml/min, p < 0.05). In both groups, breathing 100% oxygen significantly increased portal flow (to 8.4+/-1.0 and 12.2+/-0.7 ml/min, respectively). This effect was not secondary to hepatic arterial vasoconstriction because it was not prevented by hepatic artery ligation. In controls, breathing 100% oxygen increased portal pO2 from 5.0+/-0.9 to 14.4+/-1.4 kPa (p < 0.05) and portal venous oxygen saturation (PSaO2) from 53.9+/-12.1% to 92.9+/-1.4% (p < 0.05), a value not significantly different from peripheral (arterial) saturation. Similarly, in diabetic animals pO2 rose from 5.6+/-0.3 to 11.7+/-0.4 kPa (p < 0.01) and SO2 from 55.5+/-5.2% to 88.5+/-0.6% (p < 0.05). Hepatic oxyhemoglobin rose and deoxyhemoglobin fell reciprocally as a function of the inspired oxygen concentration. Improved hepatic oxygenation observed in animals breathing oxygen-enriched gas mixtures results from an increase in splanchnic blood flow coupled with a marked increase in portal oxygen saturation. This effective arterialization of portal blood may have important consequences for the success of intraportal transplantation of pancreatic islets.

Production of tissue factor by pancreatic islet cells as a trigger of detrimental thrombotic reactions in clinical islet transplantation

Intraportal transplantation of pancreatic islets offers improved glycaemic control and insulin independence in type 1 diabetes mellitus, but intraportal thrombosis remains a possible complication. The thrombotic reaction may explain why graft loss occurs and islets from more than one donor are needed, since contact between human islets and ABO-compatible blood in vitro triggers a thrombotic reaction that damages the islets. We investigated the possible mechanism and treatment of such thrombotic reactions. Coagulation activation and islet damage were monitored in four patients undergoing clinical islet transplantation according to a modified Edmonton protocol. Expression of tissue factor (TF) in the islet preparations was investigated by immunohistochemistry, immunoprecipitation, electron microscopy, and RT-PCR. To assess TF activity in purified islets, human islets were mixed with non-anticoagulated ABO-compatible blood in tubing loops coated with heparin. Coagulation activation and subsequent release of insulin were found consistently after clinical islet transplantation, even in the absence of signs of intraportal thrombosis. The endocrine, but not the exocrine, cells of the pancreas were found to synthesise and secrete active TF. The clotting reaction triggered by pancreatic islets in vitro could be abrogated by blocking the active site of TF with specific antibodies or site-inactivated factor VIIa, a candidate drug for inhibition of TF activity in vivo. Blockade of TF represents a new therapeutic approach that might increase the success of islet transplantation in patients with type 1 diabetes, in terms of both the risk of intraportal thrombosis and the need for islets from more than one donor.

Intraportal transplantation of pancreatic islets into livers of diabetic rats. Reinnervation of islets and regulation of insulin secretion by the hepatic sympathetic nerves

Intraportal transplantation of pancreatic islets into livers of diabetic rats. Reinnervation of islets and regulation of insulin secretion by the hepatic sympathetic nerves

Intraportal transplantation of pancreatic islets into livers of diabetic rats. Reinnervation of islets and regulation of insulin secretion by the hepatic sympathetic nerves.

Two weeks after intraportal transplantation of 2,000 neonatal pancreatic islets, recipient rats completely recovered from streptozotocin-induced diabetes. The reversal of diabetes could be documented by the normalization of blood glucose levels, by a restored weight gain, by normal glucagon and insulin levels in blood, and by a disappearance of polyuria and polydipsia. The reversal remained stable for at least 9 months. This study determined whether intraportally transplanted pancreatic islets were reinnervated after transplantation and whether the secretion of insulin and glucagon from pancreatic islets might be modulated by the vegetative innervation of recipient livers. Predominantly catecholaminergic but also cholinergic nerve fibers were detected not only within the portal tracts around hepatic arteries, portal veins, and bile ducts, but also at the borderline of hepatocytes and beta-cells and in islet cell complexes between beta-cells. Corresponding electron micrographs showed beta-cells in close contact with axons of nonmyelinated nerve fibers. Isolated livers were single pass perfused via both the hepatic artery and the portal vein. An increase in glucose level from 5 to 14 mmol/l enhanced hepatic glucose uptake and increased insulin secretion from transplanted islets with a biphasic secretion profile but had no effect on glucagon output. Stimulation of the nerve plexus around the hepatic artery and the portal vein (7.5 Hz, 2 min), which activates primarily the sympathetic system, not only reduced glucose uptake and perfusion flow but also completely reversed the glucose-stimulated increase in insulin secretion. Nerve stimulation did not influence glucagon secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute hepatocellular damage following intraportal transplantation of pancreatic islets in rats

Acute hepatocellular damage following intraportal transplantation of pancreatic islets in rats