Researchers explain why insulin production decreases in type 2 diabetes

Researchers have shown why insulin secretion may not work properly in people with type 2 diabetes.
Insulin resistance, the reduced ability of the body to respond to insulin, is the key characteristic of type 2 diabetes. However, insulin secretion can also be problematic in people with type 2 diabetes.
Researchers from Uppsala and Lund universities have now identified a new factor that can affect insulin, which is produced by beta cells in the pancreas.
For insulin to be released, vesicles (which transport molecules and other fluids through cells) fuse with the cell membrane, and insulin is then ejected into the bloodstream.
In a comparison of beta cells from people with and without type 2 diabetes, the defect was noted in the attachment of insulin vesicles to the cell membrane.
People with type 2 diabetes had dramatically slowed arrival of new vesicles at the cell membrane, which the researchers attributed to a reduction of proteins responsible for these attachments.
“Here, we show that human insulin secretion […] critically depend on the availability of membrane-docked granules and that T2D is associated with a strong reduction in granule docking,” said the researchers.
This so-called granule docking was shown to work normally in people without diabetes, which was accelerated by glucose. But glucose failed to replicate this process in people with type 2 diabetes, indicating that when the body becomes overworked in regulating glucose, its processes slow down.
“The findings establish granule docking as an important glucose-dependent step in human insulin secretion that is dysregulated in T2D,” the authors concluded.
The findings have been published online in the journal Cell Metabolism.
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