When a living being dies, we all usually think that life, in an instant, goes out. Kind of like someone pushed the light switch. Unexpectedly, however, some scientists have discovered that our brains – or part of it – are still active, even after death. This is what happens after a living being is declared dead. What happens to our body after death
The real question is: what we are
On closer inspection we are nothing more than an accumulation of cells that make up tissues and organs, without which life could not exist. We can therefore say that the existence of a human being is closely linked to the vitality of cells. But if we declare an individual dead and his cells are still active, we should perhaps revise the concept of death
. Scientists have discovered that in the hours following death, some brain cells are not only still active, but more than normal. These, in fact, have been shown to increase activity by gigantic proportions, astonishing the scientists of the University of Illinois at Chicago who have dealt with the study and the surprising discovery. Gene expression also increases after death
The research, published in Scientific Reports, examined the gene expression of fresh brain tissue collected during routine surgery. From the results it emerged that this expression, in many cells, increases dramatically after death. These are those that have been renamed as zombie genes, i.e. those that increased expression after the post-mortem interval and were specific to certain types of cells in particular: glial cells. From the results it emerged that these cells sprout – only after death – appendages similar to the arms. Cells Continue to Live After Death: A Surprising Research “The fact that glial cells enlarge after death is not too surprising given that they are inflammatory and their job is to clean things up following brain injuries such as oxygen deprivation or stroke, ”explained Dr. Jeffrey. Loeb, Professor John S. Garvin, chief of neurology and rehabilitation at the UIC College of Medicine. What is significant, Loeb says, are the implications of this finding: Most research studies using post-mortem human brain tissue to find treatments and potential cures for disorders like autism, schizophrenia and Alzheimer’s disease , do not take into account post-mortem gene expression or cellular activity. We really die when the heart stops beating
“Most studies assume that everything in the brain stops when the heart stops beating, but it doesn’t. Our findings will be needed to interpret human brain tissue research. We have not quantified these changes so far ». Loeb and his team noted that the global pattern of gene expression in fresh human brain tissue did not match any of the published reports on postmortem brain gene expression from people without neurological disorders or from people with a wide variety of neurological disorders. , ranging from autism to Alzheimer’s. ‘We decided to run a simulated death experiment by observing the expression of all human genes, at time points from 0 to 24 hours, from a large block of recently harvested brain tissue.24 hours after death, nothing has changed
The scientists found that around 80% of the genes analyzed remained relatively stable for 24 hours, so there were no noticeable changes in gene expression. This included genes that provide basic cellular functions and which are commonly used in research studies to show tissue quality. However, another group of genes, known to be present in neurons and intricately involved in human brain activity such as memory, thinking and seizure activity, has rapidly degraded. These genes, Loeb said, are important to researchers studying disorders like schizophrenia and Alzheimer’s disease. A third group of genes, the “zombie genes”, increased their activity while the neuronal genes were decreasing. The pattern of post mortem changes peaked at approximately 12 hours. “Our findings don’t mean that we should throw away human tissue research programs, it just means that researchers need to take these genetic and cellular changes into account and reduce the post-mortem interval as much as possible to reduce the magnitude of the changes. The good news from our findings is that we now know which genes and cell types are stable, which degrade and which increase over time, so the results of post-mortem brain studies can be better understood, ”Loeb concludes. it just means that researchers must take these genetic and cellular changes into account and shorten the post mortem interval as much as possible to reduce the extent of the changes. The good news from our findings is that we now know which genes and cell types are stable, which degrade and which increase over time, so the results of post-mortem brain studies can be better understood, ”Loeb concludes. it just means that researchers must take these genetic and cellular changes into account and shorten the post mortem interval as much as possible to reduce the extent of the changes. The good news from our findings is that we now know which genes and cell types are stable, which degrade and which increase over time, so the results of post-mortem brain studies can be better understood, ”Loeb concludes.
The “zombie” cells come to life after the death of the human brain. (Image: Dr. Jeffrey Loeb / UIC).
Loeb and director of the UI NeuroRepository, a bank of human brain tissue from patients with neurological disorders who have consented to the collection and storage of tissue for research after their death or during standard surgery to treat disorders such as epilepsy. For example, during some surgeries to treat epilepsy, epileptic brain tissue is removed to help eliminate seizures. Not all tissue is needed for pathological diagnosis, so some can be used for research. This is the fabric that Loeb and colleagues analyzed during their study.
La ricerca e stata finanziata da sovvenzioni del National Institutes of Health (R01NS109515, R56NS083527 e UL1TR002003).
Fonti scientifiche
Fabien Dachet, James B. Brown, Tibor Valyi-Nagy, Kunwar D. Narayan, Anna Serafini, Nathan Boley, Thomas R. Gingeras, Susan E. Celniker, Gayatry Mohapatra, Jeffrey A. Loeb. Selective time-dependent changes in activity and cell-specific gene expression in human postmortem brain. Scientific Reports, 2021; 11 (1) DOI: 10.1038/s41598-021-85801-6
Zombie’ genes
Research shows some genes come to life in the brain after death – UIC University
