A new study has uncovered a hidden role for the brain in type 2 diabetes.

For decades, type 2 diabetes was thought of by researchers as a disease rooted in the body's peripheral systems, where insulin resistance leads to high blood sugar levels. But a new study has found that a group of neurons in the hypothalamus may play a more significant role than previously thought, reports ScienceBlog.

In a study published in the Journal of Clinical Investigation, researchers from the University of Washington examined the role of agouti-related peptide, (AgRP) neurons in the arcuate nucleus of the hypothalamus. These neurons are known to regulate appetite and energy balance.

Using a genetic method, the researchers silenced the overactive AgRP neurons of diabetic mice by injecting a virus carrying a wood toxin into the arcuate nucleus, Focus writes. This intervention deprived the neurons of the ability to communicate with other cells without destroying them.

As a result, this intervention led to the normalization of blood sugar levels—from diabetic to normal—within a week, and this level remained stable throughout the entire 10-week study period, without affecting the mice's weight and food intake.

Further analysis showed that the level of insulin in the blood plasma decreased significantly, which indicates improved insulin sensitivity. In addition, the content of glycogen in the liver increased, which indicates better processing of glucose by the liver. Moreover, the researchers did not observe changes in liver fat content or gluconeogenic gene expression, suggesting that the improved blood sugar control occurs through mechanisms different from those used in traditional diabetes treatments.

This finding challenges the conventional view that obesity and diabetes are inextricably linked. The fact that silencing AgRP neurons normalized blood sugar levels without affecting body weight or food intake suggests that different brain circuits can independently control metabolism and eating behavior. This may explain why some diabetes treatments are effective without significant weight loss.

Although studies in mice are not always directly transferable to humans, they have a link to existing diabetes treatments. For example, GLP-1 receptor agonist drugs, such as Ozempic, are known to suppress AgRP neurons. Dr. Michael Schwartz, the study's lead author, noted that the extent to which this effect contributes to the antidiabetic effects of these drugs is still unknown, suggesting a potential mechanism for these drugs to work beyond weight loss.

Researchers are continuing to study the role of the brain in the development of diabetes, and their findings are prompting a reevaluation of the underlying mechanisms of the disease. Rather than viewing type 2 diabetes solely as a peripheral metabolic disorder caused by obesity, it could also be viewed as a brain disorder in which overactive neurons cause blood sugar levels to rise regardless of body mass, the authors write.

Such a change in perspective could ultimately lead to the creation of more effective treatments for the disease, which affects hundreds of millions of people around the world.