The Effects of Beta-cell Mass and Function, Intercellular Coupling, and islet Synchrony on Ca2+ Dynamics in Patients with Type 2 Diabetes Mellitus
Type 2 diabetes (T2D) is a challenging metabolic disorder characterized by a substantial loss of beta-cell mass via progressive programmed cell death and alteration of beta-cell function in the islets of Langerhans, disrupting insulin secretion and glucose homeostasis. The mechanisms for deficiency in beta-cell mass and function during the hyperglycemia development and T2D pathogenesis are complex. To study the relative contribution of beta-cell mass to beta-cell function in T2D, we make use of a comprehensive electrophysiological model from human beta-cell clusters. We find that defect in beta-cell mass causes a functional decline in single beta-cell, impairment in intra-islet synchrony, and changes in the form of oscillatory patterns of membrane potential and intracellular Ca2+ concentration, which can lead to changes in insulin secretion dynamics and insulin levels. The model demonstrates good correspondence between suppression of synchronizing electrical activity and pulsatile insulin release, and published experimental measurements. We then compare the role of gap junction-mediated electrical coupling with both beta-cell synchronization and metabolic coupling in the behavior of Ca2+ concentration dynamics within human islets. Our results indicate that inter-beta-cellular electrical coupling depicts a more important factor in shaping the physiological regulation of islet function and in human T2D. We further predict that varying the conductance gating of delayed rectifier K+ channels modifies oscillatory activity patterns of the beta-cell population lacking intercellular coupling, which significantly affects Ca2+ concentration and insulin secretion.
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Posted 29 Dec, 2020
Received 16 Jan, 2021
On 06 Jan, 2021
On 30 Dec, 2020
On 30 Dec, 2020
On 30 Dec, 2020
On 30 Dec, 2020
Invitations sent on 27 Dec, 2020
On 27 Dec, 2020
On 23 Dec, 2020
On 23 Dec, 2020
On 19 Dec, 2020
The Effects of Beta-cell Mass and Function, Intercellular Coupling, and islet Synchrony on Ca2+ Dynamics in Patients with Type 2 Diabetes Mellitus
Posted 29 Dec, 2020
Received 16 Jan, 2021
On 06 Jan, 2021
On 30 Dec, 2020
On 30 Dec, 2020
On 30 Dec, 2020
On 30 Dec, 2020
Invitations sent on 27 Dec, 2020
On 27 Dec, 2020
On 23 Dec, 2020
On 23 Dec, 2020
On 19 Dec, 2020
Type 2 diabetes (T2D) is a challenging metabolic disorder characterized by a substantial loss of beta-cell mass via progressive programmed cell death and alteration of beta-cell function in the islets of Langerhans, disrupting insulin secretion and glucose homeostasis. The mechanisms for deficiency in beta-cell mass and function during the hyperglycemia development and T2D pathogenesis are complex. To study the relative contribution of beta-cell mass to beta-cell function in T2D, we make use of a comprehensive electrophysiological model from human beta-cell clusters. We find that defect in beta-cell mass causes a functional decline in single beta-cell, impairment in intra-islet synchrony, and changes in the form of oscillatory patterns of membrane potential and intracellular Ca2+ concentration, which can lead to changes in insulin secretion dynamics and insulin levels. The model demonstrates good correspondence between suppression of synchronizing electrical activity and pulsatile insulin release, and published experimental measurements. We then compare the role of gap junction-mediated electrical coupling with both beta-cell synchronization and metabolic coupling in the behavior of Ca2+ concentration dynamics within human islets. Our results indicate that inter-beta-cellular electrical coupling depicts a more important factor in shaping the physiological regulation of islet function and in human T2D. We further predict that varying the conductance gating of delayed rectifier K+ channels modifies oscillatory activity patterns of the beta-cell population lacking intercellular coupling, which significantly affects Ca2+ concentration and insulin secretion.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the latest manuscript can be downloaded and accessed as a PDF.