But as we age, the infrastructure that carries these communication signals and the environment around them degrades, causing more and more “glitches”—that’s part of aging. In the process, our organs and tissues begin to lack the signals necessary to maintain life.
Previously, scientists associated special signaling chemicals that provide communication between our brain and fat tissues with aging in mice. Now they decided to study them more closely.
Researchers allowed one group of rodents to age “naturally” with just one twist: they tuned neurons that are at the beginning of the pathway from the brain to fat tissue so that they remain active.
These cells, DMHPpp1r17, are hidden in the hypothalamus of our brain, an important communication channel between our nervous system and the body’s hormonal system.
Incredibly, the new study found that mice with activated neurons lived 60 to 70 days longer than normal control mice, which died within the typical lifespan of about 1,000 days for laboratory mice.
Mice with activated neurons also had thicker, shinier fur and were more active as they aged, suggesting they also stayed healthier longer.
“When DMHPpp1r17 neurons are turned on, they can activate our body’s fight-or-flight response, our sympathetic nervous system, using the Ppp1r17 molecule. This taps into our body’s reserves of white adipose tissue, which release a protein called eNAMPT, which in turn regulates hypothalamic neurons, completing the circuit,” the researchers write.
Ppp1r17 is also well conserved across a variety of vertebrate species, including humans, chimpanzees, monkeys, rats, mice, cattle, rabbits, chickens, and zebras. This suggests that Ppp1r17 has some important functions throughout evolution.
With less activity, the nerves running through our fatty tissues begin to degrade, meaning that even less of the eNAMPT enzyme is produced, so even fewer hypothalamic neurons are activated, creating a self-propagating system of deterioration.
Many details remain to be determined, including whether the eNAMPT enzyme acts directly on hypothalamic neurons or whether there are other steps in between.
Scientists are also trying to figure out whether this feedback loop affects communication between other types of tissue in our body, such as skeletal muscle.