Under the Hood

Mitochondria In The Brain May Control Blood Sugar Levels, Change Shape When You Get A Sugar Rush

Blood
Our blood sugar may be controlled by more than we think. Pixabay Public Domain

As any high school science student can tell you, the mitochondria are the powerhouse of cells. In addition to energy production and respiration, though, mitochondria may also be responsible for the spike in blood sugar levels that occurs after a meal. Researchers at Yale School of Medicine have published findings in the journal Cell that could provide a better understanding of how that sugar spike affects us, and subsequently, the development of Type 2 diabetes.

The point of the study was to examine how neurons in the brain reacted to a rush of glucose. Previously, it was thought blood glucose levels were primarily controlled by insulin, a pancreatic hormone, along with the liver and muscles. This new research, however, shows mitochondria in a small set of neurons in the brain have a crucial role in systemic glucose control.

To the surprise of the team, they observed that mitochondria not only “feel” the change in circulating glucose levels, they also make adaptive changes crucial to the body’s ability to handle sugar in the blood. The researchers decided to test this by generating mouse models in which a specific mitochondrial protein called uncoupling protein 2 (UCP2) was either present or missing in varying amounts in the brain cells responsible for sensing circulating sugar levels. The results showed only cells with UCP2 present were able to control glucose levels.

“We found that when sugar increases in the body, mitochondria in subsets of brain neurons rapidly change their shape and their function is altered,” said senior author Sabrina Diano, professor in the school’s departments of obstetrics, gynecology and reproductive sciences, neurosceince, and comparative medicine, in a press release.

Diano added that what surprised the team the most was not that these changes occur in response to glucose, but that such seemingly subtle changes in a “housekeeping” cellular event in a small amount of brain cells could have such a huge impact on glucose levels, affecting many other functions.

“The findings imply that alterations in this mechanism may be crucial for the development of metabolic diseases such as type 2 diabetes, in which the body is not able to clear the blood from high levels of sugar that occur after meals,” Diano explained.

She and her team hope to focus their future research on evaluating if and how alteration of this mitochondrial mechanism in the brain is involved in the development and spread of Type 2 diabetes.

Source: Diano S, Toda C, Kim J, Impellizzeri D, Cuzzocrea S, Liu Z. UCP2 Regulates Mitochondrial Fission and Ventromedial Nucleus control of Glucose Responsiveness. Cell. 2016.

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