You would think that when a person is dead, the body would be made to do things; without blood and air circulation, the internal systems would be quickly depleted. But because of a strange quirk of biology there are such things as the living dead – living cells, at least, inside a formed body and dust.
Some cells inside human brains increase their activity after we die. These ‘zombie’ cells ramp up their sense of gene and bravely try to perform their vital actions, as if someone has forgotten to tell that they are now redundant.
Neurologist Jeffrey Loeb of the University of Illinois and colleagues watched as these cells exploded new tissues and bathed themselves with labor for hours after death.
“Most studies assume that everything in the brain stops when the heart stops beating, but this is not true,” Loeb said. “Our findings will be needed to study human brain bones. We have not yet measured these changes.”
Much of the information we have about brain disorders such as autism, Alzheimer’s, and schizophrenia, comes from tests performed on brain bones after death; this approach is crucial in finding cures, as animal models for brain scans often do not translate back to us.
This work is usually done on nappies from people who died more than 12 hours ago. By comparing gene expression in new brain tumors (removed as part of epilepsy surgery from 20 patients) to brain samples cited from deceased people, Loeb and the team found striking differences that there was a certain age or disease.
They used data on gene expression, which they later confirmed by studying brain histology, to understand changes in cell-specific activity over time from death, at room temperature.
While most gene activity remained stable for the 24 hours the team recorded, neuronal cells and gene activity decreased rapidly. Particularly remarkable, however, are glial cells increase gene expression and processes.
Cells survive the death of the human brain. (Dr. Jeffrey Loeb / UIC)
While surprising at first, this certainly makes a lot of sense, since glial cells, such as waste-eating microglia and astrocytes, are called to action when things go wrong. And dying is about how ‘wrong’ living things can go.
“These glial cells don’t expand after death surprisingly because they are inflammatory and their job is to clear things up after a brain injury like oxygen deficiency or stroke,” Loeb said.
The team then showed that the gene-expressed RNA itself does not change within 24 hours of death, so any changes in its amount must be the result of bio-processes. cognitive.
“The full gene interpretation of completely isolated human brain samples allows an unprecedented view of the genomic complexity of the human brain, due to the retention of so many different transcripts that are not present. more in postmortem cigarettes, “the researchers wrote in their paper.
This has a major impact on past and present studies using brain tension to understand diseases that involve immune responses – such as those ‘zombie’ glial cells that go up for a long time. and they throw pieces around a dying brain.
After 24 h, however, these cells also surrendered and were no different from the contaminated bones surrounding them.
“Researchers need to pay attention to these genetic and cellular changes, and reduce the post-mortem time as much as possible to reduce the magnitude of these changes,” Loeb explained.
“The good news from our findings is that we now know which genes and cell types are stable, which are declining, and which will go up over time so that there is a better understanding. better results from postmortem brain scans. “
Even in death, our biological bodies are never completely static.
This research was published in Scientific Reports.