Islet isolation and transplantation techniques in the primate.

Area of Science:

• Endocrinology
• Transplantation Biology
• Primate Models

Background:

• Islet transplantation is a potential therapy for type 1 diabetes.
• Optimal implantation sites and long-term graft survival in primates remain critical research areas.
• Total pancreatectomy in primates provides a model for studying islet autotransplantation.

Purpose of the Study:

• To evaluate different anatomical sites for islet transplantation in primates.
• To assess the long-term function and viability of transplanted islets.
• To identify factors influencing graft success and failure in a primate model.

Main Methods:

• Autotransplantation of pancreatic islets into monkeys following total pancreatectomy.
• Comparison of kidney subcapsular and splenic implantation sites.
• Histological examination and functional assessment (fasting glucose, glucose tolerance tests) of islet grafts.

Main Results:

• The spleen proved to be a more effective site than the kidney for islet implantation, leading to fasting normoglycemia in many animals.
• Intrasplenic islet grafts showed good morphological preservation and balanced cell populations (insulin, glucagon, somatostatin) at 4-6 weeks.
• Portal vein islet transplantation demonstrated good short and long-term function, with grafts in successful recipients remaining functional up to 2.5 years.

Conclusions:

• The spleen is a favorable site for primate islet transplantation, supporting sustained normoglycemia.
• Early graft function predicts long-term success, highlighting the importance of initial graft quality.
• Further improvements in islet isolation and implantation techniques are warranted to enhance therapeutic potential.