Life and death would not be the only states of biological organisms. Scientists have discovered a third state, a kind of cellular rebirth, which promises a considerable advance for medicine.
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A group of cell biologists claims to have discovered a “third estate”, which goes against traditional definitions of life and death.
Death is generally defined in the scientific community as “the irreversible cessation of the general functioning of a living being”. However, processes such as organ donation show how tissues, organs and cells can continue to live for some time after the death of an organism.
Two biologists named Peter Noble, associate professor of microbiology at the University of Alabama at Birmingham, and Alex Puzhitkov, director of bioinformatics at the Earl and Manella School of Biological Sciences in Hope City, explain in an article published in The Conversation how the emergence of new multicellular organisms allows us to break with conventional definitions of life and death.
Researchers explored the processes that allow cells to continue functioning after an organism dies and that make organ transplants possible.
Their research showed that Cells from dead animals are able to spontaneously adapt to the conditions of laboratory petri dishes by forming new multicellular structures called “xenobots”.
New autonomous cellular structures
The xenobots present behaviors that go far beyond their original biological functions.
For example, new multicellular structures made from cells of dead frog embryos used their cilia – small hair-like bumps – to move through their environment, whereas in living embryos these cilia are typically used to move mucus.
These new “xenobots” also have the unique ability to perform kinematic self-replication, that is, to modify their physical form as well as their function without regard to their original function.
Studies have shown that human lung cells can spontaneously assemble into small multicellular organisms capable of movement.
These “anthrobots” also exhibit new behaviors and structures and can not only maneuver in their environment, but also repair themselves and damaged nerve cells nearby.
The results of this research revealed remarkable adaptations of cellular systems and challenged the idea that cells and organisms only evolve in predetermined ways.
This “third state” concept also suggests that the process of death of organisms can significantly influence the evolution of life over time.
Can life be preserved after death?
The ability of cells and tissues to survive and function after the death of an organism is influenced by several factors, including environmental conditions, metabolic activity, and preservation methods.
Different cell types have different survival times. In humans, for example, white blood cells are generally destroyed within 60 to 86 hours of death.
On the other hand, mouse skeletal muscle cells can be regenerated up to 14 days after death and sheep and goat fibroblast cells can be implanted about a month after death.
ADVERTISEMENTTo determine whether cells can continue to survive and function after death, their metabolic activity must be monitored. It is more difficult to keep cells alive that require a large and constant supply of energy than cells that require less energy.
Techniques such as freezing also make it possible to prolong the cellular activity of certain tissue samples.
Many factors come into play
Innate survival mechanisms are also essential for cell and tissue survival.
In genes related to stress and immunity, researchers observed a significant increase in postmortem activityprobably in response to a loss of hemostasis – the process of preventing blood loss from healthy vessels and stopping bleeding from damaged vessels.
ADVERTISEMENTFactors such as trauma, infections, and time since death also have a significant effect on the survival rate of tissues and cells.
Finally, variables like age, general health or gender also influence post-mortem conditions.
This is particularly evident in problems related to the cultivation and transplantation of islet cells – responsible for insulin production in the pancreas – between organ donors and recipients.
