“Most studies assume that everything in the brain stops when the heart stops beating, but it doesn’t,” explained Jeffrey Loeb, a neurologist working at the University of Illinois. It is not an exhaustive denial, nor an inexplicable phenomenon, “we just haven’t quantified these changes so far” and, if you look closely, they very interesting changes that may have important implications in biomedical science.
Because, there, sheltered inside the skull, there are some brain cells that become more active and grow after death, who strive to continue fulfilling their role despite the fact that everything is already lost. As if they were those Japanese soldiers who did not surrender after the end of World War II.
And that, although it is not obvious from the outset, has consequences. Because, as Loeb himself reflects, much of the information we have on many neurological disorders is based on essentially dead tissue. If tissues change after death, Can we be sure that the neurobiological substrate of the disorders is what we think?
To verify this, Loeb and his team compared fresh tissues (taken from 20 patients who underwent epilepsy surgery) with tissues that had been dead for more than 12 hours. They examined gene expression, the specific activity of cells, and the structure of the tissues themselves. Their findings suggest that most of the genomic activity was stable for 24 hours, the generic activity was quickly depleted.
The funny thing is, for example, that glial cells not only were not depleted but their expression increased. It is something that, moreover, makes sense: these types of cells start up when things go wrong and “feed” precisely on waste. However, measuring these processes (which, however logical they were, were relatively forgotten) is a matter of the utmost importance.
Why? According to Loeb, because “researchers must take into account these genetic and cellular changes, and reduce the postmortem interval as much as possible to reduce the magnitude of these changes. “It is the only way that” brain studies post mortem can be better understood. “
Image | David Matos