Intraportally transplanted pancreatic islets revascularized from hepatic arterial system

Area of Science:

• Transplantation Biology
• Vascular Biology
• Endocrinology

Background:

• Intraportal transplantation is a common method for pancreatic islet grafting.
• Understanding the revascularization process of these grafts is critical for successful engraftment and function.
• The primary source of blood supply to intraportally transplanted islets remains incompletely understood.

Purpose of the Study:

• To investigate the revascularization patterns of intraportally transplanted pancreatic islets in mice.
• To determine the contribution of the hepatic artery versus the portal vein to islet graft vascularization.
• To assess the impact of hyperglycemia on islet graft revascularization.

Main Methods:

• Syngeneic pancreatic islets were transplanted intraportally into normoglycemic and diabetic C57BL/6 mice.
• Microspheres were injected via the portal vein or abdominal aorta at various time points post-transplantation.
• The presence and distribution of microspheres within liver sections containing islet grafts were analyzed.

Main Results:

• Intra-arterial microsphere administration resulted in significantly higher islet graft occupancy compared to intraportal administration.
• Approximately 20-30% of islet sections contained microspheres when administered arterially 2 weeks post-transplantation.
• Intraportally implanted islets in hyperglycemic mice showed reduced revascularization compared to normoglycemic controls.

Conclusions:

• Intraportally transplanted pancreatic islets are primarily revascularized by the hepatic artery.
• Islet graft revascularization commences within the first week post-implantation.
• Hyperglycemia negatively influences the revascularization of intraportally transplanted pancreatic islets.