{beta}-Cell function following human islet transplantation for type 1 diabetes

Area of Science:

• Endocrinology
• Immunology
• Transplantation Biology

Background:

• Islet transplantation is a potential treatment for type 1 diabetes, aiming to restore metabolic stability.
• However, achieving insulin independence often requires multiple donor pancreases due to impaired graft function.

Purpose of the Study:

• To investigate mechanistic defects contributing to suboptimal islet graft function post-transplantation.
• To assess beta-cell function and secretory capacity in patients following intraportal islet transplantation.

Main Methods:

• Studied patients at 3 and 12 months post-intraportal islet transplantation.
• Assessed C-peptide responses to intravenous glucose, oral meal, and intravenous arginine.
• Utilized a glucose-potentiated arginine test to evaluate beta-cell secretory capacity (AR(max)).

Main Results:

• Beta-cell function, measured by C-peptide response, was significantly impaired in both 3-month and 12-month transplant groups compared to controls.
• Impairment was most pronounced following intravenous glucose challenge.
• The 12-month group showed greater impairment than the 3-month group.
• Insulin-independent subjects exhibited impaired glucose-potentiation slope and maximal arginine-stimulated insulin release (AR(max)).

Conclusions:

• Impaired beta-cell function is evident at both 3 and 12 months post-islet transplantation.
• Reduced beta-cell secretory capacity suggests diminished functional beta-cell mass.
• A low engrafted beta-cell mass is likely responsible for the observed functional deficits after islet transplantation.