Lazy Insulin Granules.

“Lazy Insulin Granules”

Sujatha Ramasamy, Scientist, New Delhi.

Diabetes is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced. This high blood sugar produces the classical symptoms of polyuria (frequent urination), polydipsia (increased thirst) and polyphagia (increased hunger).

There are interesting information on diabetes research reveleas that Dr. Herbert Gaisano, a researcher at the Toronto Western Research Institute, at the University of Toronto, shows the role of SNARE protein known as VAMP8 is crucial to inducing "newcomer insulin secretory granules" to move to the front of the line and fuse to the plasma membrane, where they are able to release insulin into the bloodstream."In patients with diabetes, the granules become lazy, meaning they don't want to fuse to the plasma membrane, which they need to do so in order to release insulin," said Dr. Gaisano, the study's lead author. "Newcomer granules, on the other hand want to reach the plasma membrane and fuse right away -- this is why VAMP8 is so important, this protein makes newcomers rush to the front and fuse, and which actually more than compensated for the lazy granules."Thus this new information paves way to explain how the new class of diabetes drugs that mimic glucagon-like peptide (GLP)-1 works to increase insulin secretion in the body, which Dr. Gaisano's group has found in this study to be acting via VAMP8. With a better understanding of the exact mechanisms that influence GLP-1 drug actions (a major focus of research in Toronto), future drug therapies can be made more effective.A second set of findings where also revelead by the Gaisano team that the absence of VAMP8 causes more islet beta cell growth, by directly influencing beta cell division i.e. mitosis. This is of importance since beta cells are destroyed in type 1 diabetes (most common type in children) and the latter stages of type 2 diabetes (in adults), and hence inducing an increase in beta cell proliferation would be of great benefit to all diabetic patients.

This discovery in Toronto on a novel mechanism of insulin secretion and beta-cell growth continues the excellence and proud history that started from the discovery of insulin by Banting (Nobel Prize, 1923), Macleod (Nobel Prize, 1923), Collip and Best in Toronto. This underscores the need to sustain the almost century-long support for diabetes research at the most basic science and molecular level. "While insulin and other therapies help people living with diabetes successfully manage the disease for many years, it remains a condition that adversely impacts many organs (heart, kidneys, and eyes) of the body causing many health complications," said Dr. Gaisano.

Reference: Diabetes Research Reveals Important Link to Overcoming 'Lazy Insulin Granules'

ScienceDaily (July 26, 2012)