Single-centre experience of extending indications for percutaneous intraportal islet autotransplantation (PIPIAT) after pancreatic surgery to prevent diabetes: feasibility, radiological aspects, complications and clinical outcome

Interventional Radiological Management and Prevention of Complications after Pancreatic Surgery: Drainage, Embolization and Islet Auto-Transplantation

Pancreatic surgery still remains burdened by high levels of morbidity and mortality with a relevant incidence of complications, even in high volume centers. This review highlights the interventional radiological management of complications after pancreatic surgery. The current literature regarding the percutaneous drainage of fluid collections due to pancreatic fistulas, percutaneous transhepatic biliary drainage due to biliary leaks and transcatheter embolization (or stent–graft) due to arterial bleeding is analyzed. Moreover, also, percutaneous intra-portal islet auto-transplantation for the prevention of pancreatogenic diabetes in case of extended pancreatic resection is also examined. Moreover, a topic not usually treated in other similar reviewsas percutaneous intra-portal islet auto-transplantation for the prevention of pancreatogenic diabetes in case of extended pancreatic resection is also one of our areas of focus. In islet auto-transplantation, the patient is simultaneously donor and recipient. Differently from islet allo-transplantation, it does not require immunosuppression, has no risk of rejection and is usually efficient with a small number of transplanted islets.

Cell Therapy for Type 1 Diabetes: From Islet Transplantation to Stem Cells

The field of cell therapy of type 1 diabetes is a particularly interesting example in the scenario of regenerative medicine. In fact, β-cell replacement has its roots in the experience of islet transplantation, which began 40 years ago and is currently a rapidly accelerating field, with several ongoing clinical trials using β cells derived from stem cells. Type 1 diabetes is particularly suitable for cell therapy as it is a disease due to the deficiency of only one cell type, the insulin-producing β cell, and this endocrine cell does not need to be positioned inside the pancreas to perform its function. On the other hand, the presence of a double immunological barrier, the allogeneic one and the autoimmune one, makes the protection of β cells from rejection a major challenge. Until today, islet transplantation has taught us a lot, pioneering immunosuppressive therapies, graft encapsulation, tissue engineering, and test of different implant sites and has stimulated a great variety of studies on β-cell function. This review starts from islet transplantation, presenting its current indications and the latest published trials, to arrive at the prospects of stem cell therapy, presenting the latest innovations in the field.

Portal Vein Thrombosis May Be More Strongly Associated With Islet Infusion Than Extreme Thrombocytosis After Total Pancreatectomy With Islet Autotransplantation

BACKGROUND

Total pancreatectomy with islet autotransplantation (TPIAT) involves pancreatectomy, splenectomy, and reinjection of the patient's pancreatic islets into the portal vein. This process triggers a local inflammatory reaction and increase in portal pressure, threatening islet survival and potentially causing portal vein thrombosis. Recent research has highlighted a high frequency of extreme thrombocytosis (platelets ≥1000 × 109/L) after TPIAT, but its cause and association with thrombotic risk remain unclear.

METHODS

This retrospective single-site study of a contemporary cohort of 409 pediatric and adult patients analyzed the frequency of thrombocytosis, risk factors for thrombosis, and antiplatelet and anticoagulation strategies.

RESULTS

Of 409 patients, 67% developed extreme thrombocytosis, peaking around postoperative day 16. Extreme thrombocytosis was significantly associated with infused islet volumes. Thromboembolic events occurred in 12.2% of patients, with portal vein thromboses occurring significantly earlier than peripheral thromboses. Portal vein thromboses were associated with infused islet volumes and portal pressures but not platelet counts or other measures. Most thromboembolic events (82.7%) occurred before the postoperative day of maximum platelet count. Only 4 of 27 (14.8%) of portal vein thromboses occurred at platelet counts ≥500 × 109/L. Perioperative heparin was given to all patients. Treatment of reactive thrombocytosis using aspirin in adults and hydroxyurea in children was not associated with significantly decreased thromboembolic risk.

CONCLUSIONS

These results suggest that post-TPIAT thrombocytosis and portal vein thromboses may be linked to the islet infusion inflammation, not directly to each other, and further reducing this inflammation may reduce thrombosis and thrombocytosis frequencies simultaneously.

β Cell Replacement Therapy: The Next 10 Years

β cell replacement with either pancreas or islet transplantation has progressed immensely over the last decades with current 1- and 5-year insulin independence rates of approximately 85% and 50%, respectively. Recent advances are largely attributed to improvements in immunosuppressive regimen, donor selection, and surgical technique. However, both strategies are compromised by a scarce donor source. Xenotransplantation offers a potential solution by providing a theoretically unlimited supply of islets, but clinical application has been limited by concerns for a potent immune response against xenogeneic tissue. β cell clusters derived from embryonic or induced pluripotent stem cells represent another promising unlimited source of insulin producing cells, but clinical application is pending further advances in the function of the β cell like clusters. Exciting developments and rapid progress in all areas of β cell replacement prompted a lively debate by members of the young investigator committee of the International Pancreas and Islet Transplant Association at the 15th International Pancreas and Islet Transplant Association Congress in Melbourne and at the 26th international congress of The Transplant Society in Hong Kong. This international group of young investigators debated which modality of β cell replacement would predominate the landscape in 10 years, and their arguments are summarized here.