Old cells change the shape of the brain even before aging begins

Cellular senescence is a condition where cells stop dividing but do not die. They become like zombies, changing their functions and influencing their neighbors. Previously, biologists searched for them only in the elderly, but a new technique has made it possible to find traces of this process even at the earliest stages of development.

The authors of the work encountered the phenomenon of “antagonistic pleiotropy”. This is a complex term that hides a simple but cruel irony of nature: the mechanisms that are necessary for the survival and growth of the embryo turn into enemies over the years, contributing to the withering of the body. What built the brain at the beginning of life begins to break it down at the end.

The most interesting discovery is that aging affects different types of cells in different ways. Researchers have found that when microglia (the brain’s immune defense cells) age, it is associated with an increase in the volume of brain tissue. But the aging of excitatory neurons, on the contrary, leads to shrinkage of the brain and loss of volume.

The processes are not chaotic. They are clear molecular programs that work throughout life. Aging is a fundamental biological function inherent in us from the beginning.

The breakthrough was made possible by the Living Brain Project. Usually, the brain is examined either postmortem or only through MRI scans. Here, doctors were able to take tiny tissue samples from patients undergoing deep brain stimulation and immediately compare them with a map of their neural connections. Noam Beckmann, one of the leaders of the study, emphasizes: This is the first work that directly connected the molecular networks of a living person with the physical shape of his brain.

It’s too early to talk about the eternal youth pill, but understanding the mechanism is half the success. If doctors learn to distinguish between “good” aging, which is necessary for development, and “bad” aging, which leads to diseases, this will open the way to fundamentally new methods of treating neurodegenerative diseases.

Brian Kopell, director of the Center for Neuromodulation, noted that often the greatest discoveries are made not through the invention of something new, but through a unique look at what is already in hand. The evidence that senility can be embedded in the mechanism of development challenges established dogmas and suggests looking for medicines where no one has looked before.