Glucose-induced insulin secretion in isolated human islets: Does it truly reflect β-cell function in vivo?

Area of Science:

• Endocrinology
• Diabetes Research
• Islet Cell Biology

Background:

• Type 2 diabetes involves beta-cell dysfunction and impaired insulin secretion.
• Rodent islets have been crucial in studying beta-cell pathophysiology.
• Research increasingly utilizes isolated human islets for diabetes studies.

Purpose of the Study:

• To assess the translational validity of in vitro human islet studies for understanding in vivo insulin secretion.
• To compare qualitative and quantitative aspects of glucose-induced insulin secretion in isolated human islets versus living subjects.

Main Methods:

• Review of clinical investigations and experimental studies on isolated human islets over 60 years.
• Analysis of data comparing in vitro and in vivo insulin secretion under varying glucose concentrations.
• Evaluation of discrepancies in insulin secretion kinetics between diabetic subjects and their isolated islets.

Main Results:

• In vitro human islet data generally show good qualitative and quantitative coherence with in vivo insulin secretion under physiological glucose stimulation.
• Concordance between in vitro and in vivo findings diminishes under extreme conditions.
• Significant discrepancies exist in insulin secretion kinetics between Type 2 diabetic subjects and their isolated islets studied in vitro.

Conclusions:

• Information from in vitro human islet studies is largely translatable to the in vivo situation for normal physiological conditions.
• Future research must ensure experimental conditions closely mimic physiological states to avoid altering islet function.
• Refined experimental designs are needed to resolve discrepancies, particularly in Type 2 diabetes research.