The death of an organism does not spell the end for its cells, according to new research. Cells have been shown to continue to function even after the organism they originated from is deceased, oftentimes developing new biological functions. The findings call into question what defines life and death, and open up a new area of medicine.
The cells go marching on
The new research, published in the journal Physiology, suggests the boundary between life and death may not be as clear-cut as previously thought. “Life and death are traditionally viewed as opposites,” said study co-authors Peter Noble, a microbiology professor at the University of Alabama at Birmingham, and Alex Pozhitkov, a bioinformatics researcher at the City of Hope cancer center, on The Conversation. “However, the emergence of new multicellular lifeforms from the cells of a dead organism introduces a ‘third state’ that lies beyond the conventional boundaries of life and death.”
There has been a range of evidence that the death of an organism does not necessarily signal the death of its cells, especially with organ, tissue and cell transplants. The new review expands on that idea, looking at other studies showing “the incredible capability of cells to reorganize and take on new forms after the death of the organism,” said Earth.com. Essentially, “under the right conditions — when provided with nutrients, oxygen, bioelectricity or biochemical cues — certain cells can grow into multicellular organisms with new functions after death,” said IFLScience.
One of the most promising pieces of research was a 2021 study that found the skin cells from dead frogs could spontaneously reorganize to form multicellular organisms called “xenobots.” These are “cells that form new roles beyond their original biological function,” said Popular Mechanics, like “using hairlike cilia for locomotion rather than transporting mucus.” Xenobots also showed the ability to collect material, record information, self-heal and limit replication. Similar results have been found in human lung cells, “which can assemble into miniature multicellular organisms called anthrobots, move around and even repair themselves and nearby neurons,” said IFL Science.
Beyond death
Both of those findings “demonstrate the inherent plasticity of cellular systems and challenge the idea that cells and organisms can evolve only in predetermined ways,” said Noble and Pozhitkov. “The third state suggests that organismal death may play a significant role in how life transforms over time.”
Cells can enter a third state only under certain conditions, however, and researchers are still not entirely sure how they can continue to function after the death of the organism. One explanation, “reminiscent of Frankenstein-style ideas,” said Earth.com, “involves a hidden system of ‘electrical circuits’ that reanimate the cells.” Others have posited that when “cells are taken out of context and are no longer exchanging information or signals from nearby cells, different genes can be expressed than what’s normal,” said Popular Mechanics. The findings have also given rise to the idea that cells may have a level of “consciousness” that allows them to have their own agency.
Exploring this third state “represents a novel and exciting avenue for medical research,” Noble said to IFL Science. “Cells in the third state may potentially be engineered to solve medical problems, such as serving as drug delivery systems.”