Some of our brain cells become more active hours after we die, research shows

Even after we’re dead, some of our brain cells may experience one last and major momentary burst of life, new research suggests Tuesday. The study found evidence that certain “zombie genes” in our brain cells are more active shortly after death, causing some cells to expand enormously for hours. The findings won’t radically change our views on life and death, but they may have some important implications for studying brain tissue taken post-mortem.

It’s no secret that our cells can live and function for a while, even after we’re clinically dead, before they eventually die out. But while almost every cell contains the same genetic information as the other, different types of cells express this genetic information differently, turning different genes on or off. And when the researchers looked at the gene expression of different cells in a “dying brain,” they discovered some clear patterns.

For their studies, published In Scientific Reports on Tuesday, the team looked at samples of brain tissue donated by patients who had recently undergone brain surgery for epilepsy (surgical treatments can safely remove parts of the brain involved in the seizure disorder). They then mimicked the brain death process by omitting the freshly removed samples at room temperature for various time periods, up to 24 hours. All the while, the team gathered information about the cellular and genetic activity of these cells.

In a majority of the genes they studied, characterized as “housekeeping genes” that maintain basic cellular function, they found that the genes remained at the same level of activity throughout the 24-hour period. In the “neuronal” genes, genes out there turned on in the neuron cells responsible for brain functions such as thinking and memory, their activity began to decline after 12 hours.

But in a third group of genes, linked to the function of glial cells – the immune and supportive systems of the brain – gene expression actually increased after “death” and continued to increase until 24 hours later. The glial cells themselves also grew enormously in size and even new “arms” were added as the neurons in these samples were degenerating.

T.The results don’t prove that zombies are theoretically possible, anyAnd it’s not even a big surprise that glial cells are particularly active after death. The cells likely respond to the injury and inflammation that occurs in the brain when they run out of oxygen after someone’s last moments. But the findings pose a potential wrinkle in the way much human brain research is conducted, according to the authors, as many studies rely on post-mortem examinations of the brain.

“Most studies assume that everything in the brain stops when the heart stops beating, but this is not so,” said study author Jeffrey Loeb, chief of neurology and rehabilitation at the University of Illinois at the Chicago College of Medicine. a pronunciation released by the university. “Our findings are necessary to interpret research on human brain tissue. We just haven’t quantified these changes so far. “

One problem is that research into conditions such as Alzheimer’s disease and other forms of dementia often depend on post-mortem brain samples collected 12 or more hours later death. If the findings here are valid, many of these studies may be missing important clues in dying cells that could later be missing. Loeb and his team hope that future studies can better account for the changes that take place in a dying brain. For example, a possible solution could be to collect even earlier post-mortem brain samples for research or to rely more heavily on samples from willing patients who do undergo brain surgery.

“The good news of our findings is that we now know which genes and cell types are stable, which degrade, and which increase over time, so that the results of post-mortem brain studies can be better understood,” said Loeb.