Objective: Islets from the same pancreas show remarkable variability in glucose sensitivity. While mitochondrial respiration is essential for glucose-stimulated insulin secretion, little is known regarding heterogeneity in mitochondrial function at the individual islet level. This is due in part to a lack of high-throughput and non-invasive methods for detecting single islet function. Methods: We have developed a novel non-invasive, high-throughput methodology capable of assessing mitochondrial respiration in large-sized individual islets using the XF96 analyzer (Agilent Technologies). Results: By increasing measurement sensitivity, we have reduced the minimal size of mouse and human islets needed to assess mitochondrial respiration to single large islets of >35,000 μm2 area (∼210 μm diameter). In addition, we have measured heterogeneous glucose-stimulated mitochondrial respiration among individual human and mouse islets from the same pancreas, allowing population analyses of islet mitochondrial function for the first time. Conclusions: We have developed a novel methodology capable of analyzing mitochondrial function in large-sized individual islets. By highlighting islet functional heterogeneity, we hope this methodology can significantly advance islet research.
Bibliographical noteFunding Information:
This project was supported by NIH funding mechanisms NIDDK 5R01DK074778-10 and R01DK099618 awarded to OSS, and the UCLA Department of Medicine Chair commitment and UCSD/UCLA Diabetes Research Center Pilot and Feasibility grant NIH P30 DK063491 awarded to ML. The authors would like to thank Dr Joss Manning Fox (University of Alberta Diabetes Institute Islet Core) for isolating and shipping human islets. PM was supported by the Alberta Diabetes Foundation. We also thank Drs. Ajit Divakaruni and Karel Erion (UCLA Department of Molecular and Medical Pharmacology and Department of Medicine, Division of Endocrinology at UCLA) for their helpful input during the preparation of this manuscript. Finally, we would like to acknowledge Drs. David Ferrick and Brian Dranka (Agilent Technologies) for invaluable insight and discussions during the planning and performance of this study.