Superiority of fresh islets compared with cultured islets

Area of Science:

• Islet biology and transplantation research.
• Immunology and inflammatory responses in transplantation.
• Biomaterials and tissue engineering for regenerative medicine.

Background:

• Recent reports suggest comparable outcomes for cultured versus fresh islets in transplantation.
• Clarifying the impact of islet culture on transplant quality is crucial for optimizing procedures.
• Investigating the influence of culture media on islet quality is essential.

Purpose of the Study:

• To compare the quality of freshly isolated islets with islets cultured in different media.
• To evaluate the functional and inflammatory status of fresh versus cultured islets.
• To assess the in vivo transplantation performance of fresh and cultured islets.

Main Methods:

• Islets were cultured in CMRL 1066 with serum, albumin, or Miami medium.
• Quality assessment included glucose stimulation, insulin/DNA content, and ADP/ATP ratios.
• Tissue factor (TF) expression was analyzed via Western blotting to assess inflammatory potential.
• An intraportal transplantation model in diabetic rats was used to evaluate in vivo efficacy.

Main Results:

• Fresh islets exhibited significantly higher glucose stimulation indices and insulin/DNA ratios.
• Tissue factor expression, a marker for instant blood-mediated inflammatory reactions (IBMIR), was significantly lower in fresh islets.
• Transplantation of fresh islets resulted in higher curative rates and improved recipient insulin production.
• While islet survival rates were similar, functional outcomes favored fresh islets.

Conclusions:

• Isolated islets without prior culture demonstrated superior functional capacity and transplant outcomes.
• Culture of islets may enhance tissue factor expression, potentially increasing detrimental IBMIR.
• These findings advocate for the use of freshly isolated islets to optimize islet transplantation success.