Researchers have made a key discovery in the fight against obesity

Researchers have made a key discovery in the fight against obesity

Researchers have made a key discovery in the fight against obesity

Researchers have identified a previously unknown communication pathway that allows fat to communicate directly with the brain, at least in mice. By eliminating this connection, the rodents burned more fat. More work is needed, but disrupting this communication network could one day help cure obesity in humans.

We have known for a long time that the brain uses sympathetic nervous system neurons to tell the body to burn more fat. Until now, however, scientists believed that reverse communication (from fat to the brain) was less direct, with fat sending messages to the brain releasing hormones into the bloodstream.

A new study published in the journal Nature shows that fat also sends messages directly to the brain via sensory nerve cells called dorsal root ganglia.

Beige fat to fight obesity

Located near the spinal cord, the dorsal root ganglia (DRG) extend long strands to peripheral organs. The sensory information collected is then sent to the brain via the spinal cord. Researchers have long known that DRGs carry information from the skin and muscles to the brain. Until now, however, it has always been difficult to determine what information neurons transmit from adipose tissue to the brain via DRGs due to the difficulty of visualizing these neurons in action.

Eventually, the researchers found a way to do this. As part of this work, neuroscientist Li Ye and his team at the Scripps Research Institute in La Jolla, California, fluorescently labeled extended DRG neurons in the adipose tissue of several mice. Using a previously developed system for seeing through animal tissue, the researchers were able to observe the action of DRGs from their origins near the spinal cord to the fat pads.

As a reminder, fat comes in many colors depending on how the body uses it. Brown, for example, burns to generate heat. White is mostly memorized (that’s what you want to see disappear). Finally, beige is placed between the two. When the body needs to burn more fat, these fatty tissues can turn into brown fat in an attempt to generate heat. When the body doesn’t need to burn it, the beige fat turns white and is then stored.

These adipose tissues are therefore more “dynamic” than the others. For this reason, researchers believe they can play an important role in obesity problems. For this study, the team therefore focused on it.

fat of obesity
Credits: Pixabay / jarmoluk

“Car brakes” size

During their experiments, the researchers suppressed the DRG neurons that connected to this beige fat by means of a virus. As a result, the genes related to fat production and heat generation intensified. In other words, the mice burned more fat. Their beige fat also turned browner, a sign that the rodents’ temperatures had risen.

One way to better appreciate the process is to imagine the following analogy. If the body is a car and fat is fuel, the sympathetic nervous system acts like the accelerator pedal telling the body to burn more fuel (therefore more fat). In contrast, the newly discovered fat brain communication system appears to work like a brake pedal, acting in opposition to the accelerator pedal of the sympathetic nervous system. Here, the researchers have cut the brakes, which promoted fat burning.

Researchers speculate that this “braking system” tells the brain how much fat is being burned, ensuring that the body doesn’t burn too much. This is only preliminary work, but it would be interesting to see if such a process could be at work in humans and, if so, if this process could be manipulated in hopes of helping obese people lose weight.

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