Critical transitions in pancreatic islets

TL;DR

This study investigates the nature of calcium signaling transitions in pancreatic beta-cell collectives, revealing a hysteresis indicative of a first-order phase transition, with implications for understanding insulin release mechanisms.

Contribution

The paper demonstrates that calcium signaling transitions in pancreatic islets are first-order phase transitions with hysteresis, supported by experimental data and a network model.

Findings

Calcium signals show a sharp transition with hysteresis.

The transition is characterized as a first-order phase transition.

Network modeling captures the observed hysteresis and critical behavior.

Abstract

Calcium signals in pancreatic beta-cells collectives show a sharp transition from uncorrelated to correlated state resembling a phase transition as the slowly increasing glucose concentration crosses the tipping point. However, the exact nature or the order of this phase transition is not well understood. Using confocal microscopy to record the collective calcium activation of beta-cells in an intact islet under changing glucose concentration in increasing and then decreasing way, we first show that in addition to the sharp transition, the coordinated calcium response exhibits a hysteresis indicating a critical, first order transition. A network model of beta-cells combining link selection and coordination mechanisms capture the observed hysteresis loop and the critical nature of the transition. Our results point towards the understanding the role of islets as tipping elements in the pancreas that interconnected by perfusion, diffusion and innervation cause the tipping dynamics and abrupt insulin release.