An injury can occur at any time. Fortunately for us, our tissues have stem cells ready to multiply and take the place of the cells damaged by the accident. However, sometimes there are not enough stem cells in the injured area, or the stem cells themselves have been victims of the trauma. In these cases, it is up to adult cells to try to play nurse. But their cellular programming is often already too specialized and does not allow them to multiply as quickly as stem cells.
No problem, they have a trick, which has just been discovered by researchers at Washington University in St. Louis (USA): cells can throw away much of the machinery they acquired as they mature, a bit like an adult well accustomed to their routine getting rid of all their furniture to become more flexible. This strange way of becoming young again by "vomiting" what is cluttering them was presented on August 26, 2025 in the journal Cell Reports.
Declutter to keep only the essentials
This process was partially brought to light a few years ago by the same team, who showed that adult cells can become more immature in order to proliferate and heal a wound. To do this, they destroy part of their contents (through a cleaning process called "autophagy") and undergo cellular reprogramming. To better understand this phenomenon, the researchers used a mouse model of gastric injury. In these wounds, the urgency of repair is vital, because the gastrointestinal tissue is a barrier that protects the body from all the toxic and pathogenic material that can end up in the digestive tract. And then, surprise: to be able to multiply and thus repair the injury, the cells of this tissue don't just destroy some of the "furniture" in their house, they also throw some of it out the "window"!
This Marie Kondo-esque cleaning strategy has been dubbed "cathartocytosis" (Greek for "cellular cleansing"). During this process, the cell forms vesicles that encapsulate organelles (the cells' organs) and other cell components. Then, the cell membrane forms holes, "windows," through which these vesicles can exit the cell, ridding it of all this excess.
“After an injury, cells need to repair tissue, but mature cells have too much cellular machinery that prevents them from doing this repair. This way of cleaning the cell is a quick way to get rid of this machinery, allowing the cell to become small again and able to proliferate and repair the injury., explains in a press release Jeffrey W. Brown, co-author of the study. We identified this process in the digestive system, but we believe it also happens in other tissues.”
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A process that cleans the inside of cells, but dirty the outside
But this quick cleaning method doesn't have all the upsides. To understand this, just imagine what would happen if, while doing a major cleaning at home, you simply threw old furniture out the window, without taking it to the recycling center. They would quickly pile up in the street, littering the neighborhood and blocking traffic. This is exactly what could happen around these cells. To heal an injury, all this cellular waste is quickly deposited in the extracellular space, which can cause inflammation.
Paradoxically, this could slow down the repair of the injury, increasing the risk of it becoming chronic. Not to mention the increased risk of cancer due to the accumulation of these pro-inflammatory waste products.It's a risky process, warns Jason C. Mills, who led the study. In the stomach, cells live a long time, and they acquire mutations as they age. If many of these aging cells that have accumulated mutations start to revert to a younger stage in order to repair an injury—knowing that injuries themselves also cause inflammation—there is an increased risk that these cells acquire of mutations harmful and perpetuates themmultiplying, causing a risk of cancer.”
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The authors of this work also believe that this process of cathartocytosis could play a role in intestinal infections caused by the bacteria Helicobacter pylori, which causes chronic wounds (ulcers) and increases the risk of cancer.If we can better understand this process, we can design methods to help cells repair injuries, and in the context of chronic injury, prevent damaged cells from entering chronic cycles of cathartocytosis and thus contribute to the formation of tumors”, hopes Jeffrey W. Brown.
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