Your brain cells may be capable of outliving you—by a lot
Courtesy of PNAS and World Science staff
Some brain cells of mammals can long outlive the animal to which they originally belonged, if transplanted into a different brain, new research suggests.
The findings are raising scientists’ hopes that if they find a way to greatly increase human lifespan, brain cells will cooperate by working longer accordingly.
In mammals, neurons, the main type of information-processing brain cells, can last a whole lifespan in the absence of brain disease. But it has been unclear whether neurons have a maximum lifespan, similar to other types of cells in the body which, unlike neurons, normally can replicate.
To find out, Lorenzo Magrassi of the University of Pavia in Italy and colleagues transplanted precursor neurons from the developing mouse into rat embryos. They used a strain of rat that can live on average nearly twice as long as the donor mouse strain. The cells came from, and were transplanted to, a part of the brain known as the cerebellum.
The transplanted cells developed into normal neurons that made themselves at home in the rat brains, though they retained a mouse-like size and shape, the researchers said. Moreover, these cells survived for as long as their rat hosts, or up to 36 months, roughly twice as long as the average lifespan of the donor mice.
The findings suggest that the lifespan of the transplanted neurons is not genetically fixed and may have been determined by the rat brain “microenvironment,” Magrassi and colleagues wrote. They reported their findings in this week’s early online issue of the journal Proceedings of the National Academy of Sciences.
The results, they added, also suggest that increasing longevity—a hallmark of technologically advanced societies—won’t necessarily saddle longer-lived people with a problem of many dying brain cells.
“Our results suggest that neuronal survival and aging are coincident but separable processes,” they wrote. This increases “our hope that extending organismal lifespan by dietary, behavioral, and pharmacologic interventions will not necessarily result in a neuronally depleted brain.”
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