A new study redefines the definition of death. Scientists revealed that the body remains alive even after the heart stops -- for at least one day or two. Even after death, some genes in the body works for up to 48 hours. This new finding gives implications to forensics and organ transplant.
Death is commonly defined as the cessation of all biological functions that sustain a living organism. However, instead of a quick complete shutdown after the heart stops beating, death is more like a slow process. A study on some animals revealed that some cells in the body remain alive after death.
Researchers from University of Washington led by Peter Noble and Alex Pozhitkov studied zebrafish and mouse samples immediately after death. They measured the amount of messenger RNA (mRNA) -- genes that command the cells to make products like proteins -- in the animals. In the findings published in Open Biology, researchers revealed there is an increase in amount of mRNA suggesting the genes ae very active, trying to repair bodily damage after death.
"Not all cells are 'dead' when an organism dies," senior author Peter Noble told Seeker. "Different cell types have different life spans, generation times and resilience to extreme stress." The researchers measure the mRNA levels in the liver and brain samples of mica and zebrafish regularly for up to four days and compare them to the levels measured at exact time of death.
Even though the overall mRNA levels decreased over time, results revealed that mRNA connected to 548 zebrafish genes and 515 mouse genes recorded one or more peaks of activity even after death. This means some cells stay active even after the animal died until it exhausts all its stored energy. The researchers added that some genes that are off wakes up after death, including fetal development genes and some genes related to cancer. "Hundreds of genes with different functions woke up after death, including fetal development genes," the researchers told New Scientist.
The researchers added that the same process happens to the human body. Inactive genes turn on as part of physiological processes -- a last ditch effort to aid healing in the body. This study gives insight to organ donation, specifically on the activation of cancer genes as well as forensics. The researchers also raised a question the definition of death. If some cells or genes in the body remain alive for up to 48 hours. Does that mean the body is still technically alive?
