These sensory neurons tell the brain how much fat it should burn each day.
By analyzing adipose tissue, scientists at the Scripps Institute have found the biological messenger that controls our body fat. It’s a whole new system of sensory neurons that can tell the brain when it’s necessary to burn fat and when it’s not.
Obesity is a clinical condition increasingly recurring. About 40% of adults on the planet are overweight, and 13% are already obese. This due to metabolic problems that were believed to be associated with hormones in the blood.
However, this new study has made it clear that the newly identified neurons are the only ones capable of monitoring adipose tissue and sending that information to the brain.
We have a couple of extra neurons to fight against being overweight (or favor it)
This new neural system is located in the spinal column, but it branches out until it reaches the adipose tissue. That conglomerate of fat cells where energy is stored until the body needs it.
It has been known for several years that mammals are full of neurons even in adipose tissue. However, it is the first time that the usefulness of these neurons has been confirmed.
According to their findings, sensory neurons promote fat burning during exercise or other biological stresses such as starvation. This through automatic responses such as increasing the heart rate or dilating the eyes to consume energy.
But they can also promote fat accumulation if they lose contact with the brain.
How does this sensory system work?
Project scientists had to create new measurement tools to find this system. Among them, a cell manipulation technique called ROOT, which helped them reach the deepest neurons in adipose tissue, and a photographic technique called HYBRiD, to give neurons transparency.
Thanks to these techniques, the team clearly saw that almost half of the fat neurons did not connect to the Sympathetic Nervous System. Rather, they were part of another system that went directly to the brain.
However, when experimenting with mice, they realized that these sensory neurons work in conjunction with sympathetic neurons. While sympathetic neurons turn on fat burning and fat production, sensory neurons turn off these commands.
That is why, if they are damaged, the delicate metabolic balance is upset. The brain does not receive sensory messages from adipose tissue, so it does not consider that there is enough fat. Consequently, cells begin to store more sugars to produce heat, which over time promotes diseases such as diabetes, fatty liver disease, atherosclerosis, and obesity.
Therefore, the scientists concluded that these nerves play a crucial role within our body as “switches”.
“This tells us that there is no single instruction. These types of neurons act as an accelerator and a brake to burn fat.”
Li Ye, Associate Professor of Neuroscience at Scripps Research
What does this all mean?
Although this study did not focus on metabolic problems, it is yet another example of how important neurons are to health and disease in the human body.
Perhaps understanding this system could help people in the future who fight against being overweight and its associated health problems.
Scientists Discover a Secret Messenger Between Fat And The Brain https://www.sciencealert.com/scientists-discover-a-secret-messenger-between-fat-and-the-brain
The role of somatosensory innervation of adipose tissues https://doi.org/10.1038/s41586-022-05137-7