Kinetics of functional beta cell mass decay in a diphtheria toxin receptor mouse model of diabetes

Pim P Van Krieken,Andrea Dicker,Per-Olof Berggren,Pedro L Herrera,Maria Eriksson,Erwin Ilegems,Ulf Ahlgren

doi:10.1038/s41598-017-12124-w

Abstract

Functional beta cell mass is an essential biomarker for the diagnosis and staging of diabetes. It has however proven technically challenging to study this parameter during diabetes progression. Here we have detailed the kinetics of the rapid decline in functional beta cell mass in the RIP-DTR mouse, a model of hyperglycemia resulting from diphtheria toxin induced beta cell ablation. A novel combination of imaging modalities was employed to study the pattern of beta cell destruction. Optical projection tomography of the pancreas and longitudinal in vivo confocal microscopy of islets transplanted into the anterior chamber of the eye allowed to investigate kinetics and tomographic location of beta cell mass decay in individual islets as well as at the entire islet population level. The correlation between beta cell mass and function was determined by complementary in vivo and ex vivo characterizations, demonstrating that beta cell function and glucose tolerance were impaired within the first two days following treatment when more than 50% of beta cell mass was remaining. Our results illustrate the importance of acquiring quantitative functional and morphological parameters to assess the functional status of the endocrine pancreas.

Highlights

The pancreatic beta cells are essential for the maintenance of adequate blood glucose levels
Optical projection tomography (OPT) imaging of the insulin-stained and tissue-cleared whole mount RIP-diphtheria toxin receptor (DTR) pancreas was complemented with repeated confocal imaging of RIP-DTR islets transplanted into the anterior chamber of the eye (ACE)
Samples were scanned by OPT and images were subsequently processed and analysed, allowing the identification of insulin-positive clusters defined as islets of Langerhans (Fig. 1a,b, Supplementary Movie 1)

Summary

Introduction

The pancreatic beta cells are essential for the maintenance of adequate blood glucose levels. While OPT ensures accurate quantification of the total beta cell volume, islet number and distribution within the mouse pancreas[28], the ACE model allows to monitor the precise kinetics of BCM decay by longitudinal assessment of a small number of islet grafts serving as ‘reporters’ for changes occurring in the pancreas[29]. Information obtained this way was further combined with various physiological and functional studies at different time points, leading to a complete appreciation of functional beta cell mass in the RIP-DTR mouse model

Methods

Results

Conclusion