The genes of certain brain cells continue to be expressed after clinical death. A discovery that must be taken into account in research on autism, schizophrenia or Alzheimer’s carried out on post-mortem brain tissue.
- Inflammatory brain cell gene expression increases after death
- This discovery should allow more precise analyzes of post-mortem brain tissue in research on neurological disorders
What if all life didn’t stop when the heart stopped beating? This can be deduced from twork carried out by researchers at the University of Illinois at Chicago and published in the journal Scientific Reports. This research shows that the gene expression of brain tissue cells not only does not cease after death but even becomes even more active!
These “zombie genes”, as the researchers call them, are specific to inflammatory cells called glial cells which they have observed grow to produce long arm-like appendages “for many hours after death”. These cells are located in the brain tissue.
Inflammatory cells that clean up the effects of brain damage
“Most studies assume that everything in the brain stops when the heart stops beating, but this is not the case,” notes Dr. Jeffrey Loeb, lead author of this work. Which, moreover, finally seems quite logical to him: “The fact that glial cells enlarge after death is not too surprising given that they are inflammatory cells whose role is to make the cleaning after brain damage related to oxygen deprivation or stroke”. In other words, their genes would survive clinical death to allow them to continue performing the tasks for which they are programmed.
How did Jeffrey Loeb and his team arrive at this astonishing discovery? They took brain tissue from deceased patients as part of research into new treatments for epilepsy. And it was by analyzing these tissues that they found very different behaviors of several groups of genes. Genes that provide basic cellular functions remained stable and another group of genes, all those known to be present in neurons and involved in brain activity – thinking and memory – rapidly degraded within hours of followed by death. It was a third group, that of the “zombie genes” that caught their attention when they noticed that their activity increased, reaching a maximum level about 12 hours after death.
Better understand post-mortem brain tissue analyzes
Beyond revealing that a part of cellular life can continue after death, this observation is of interest for research concerning neurological disorders such as autism or Alzheimer’s disease: this is based in sometimes effect on analysis of post-mortem brain tissue. And the work of Jeffrey Loeb and his team, showing that this tissue can continue to evolve after death under the effect of “zombie genes”, indicates that these changes must be taken into account. And that it is preferable for such research to work on “fresh” post-mortem brain tissue or to work only on cells whose gene expression is stabilized.
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