A new study led by researchers at the University of California San Francisco specified that not all senescent cells are harmful "zombies" that need to be eliminated to avoid age-related disease.
This UCSF research specifically found that some of them are implanted in "young, healthy tissues," and they promote normal repair from damage.
📢Hot News! @UCSF press release highlighting @ucsfpenglab's most recent manuscript in @ScienceMagazine. Sentinel senescent cells of the lung are important for normal tissue repair. https://t.co/i8qr6FLNqa
— UCSF Bakar Aging Research Institute (@UCSFAging) October 17, 2022
Based on this finding, scientists have now seen the said cells in action in lung tissue, as well as other organs, serving as barriers in the body, like the small intestine, skin, and colon.
And when the team used drugs known as "senolytics" to destroy the cells, lung tissue injuries healed more slowly.
Aging Cells
According to Tien Peng, M.D., associate professor of pulmonary, critical care, sleep medicine, and allergy and the senior author of the study published in the Science journal, "senescent cells can occupy niches" with favored positions as "sentinels" that are monitoring tissues for injury and respond by activating nearby stem cells to grow and institute repair.
Peng explained that it was understandable that researchers initially saw senescent cells as "purely detrimental."
As one ages, senescent cells build up that have characteristics of old, worn-out cells, which include the inability to make new cells.
Rather than dying like normal aged cells, they indeed live on, spewing a cocktail of inflammatory compounds, forming the senescence-associated phenotype or SASP.
Such factors are associated with Alzheimer's disease, arthritis, and other age-related maladies like cancer, among others. The name "zombie cells" was derived from these maladies.
Senolytics Drugs
Using drugs called senolytics that aim and destroy zombie cells, the study investigators made the exciting discovery that clearing senescent cells from animals stopped or diminished age-related disease and extended the animals' lifespan.
Subsequently, a boom of activity occurred in research laboratories and pharmaceutical firms focused on discovering and refining more powerful editions of the said drugs.
Nonetheless, killing off senescent cells has dangers. For one thing, this present research showed that senescent cells possess the ability to promote normal healing through the activation of stem cell repair.
Describing their study, Peng explained it suggests that senolytics could negatively impact normal repair although they have the potential to target diseases, where senescent cells are driving pathologic stem cell behavior.
Green Glowing Senescent Cells Observed
A similar EurekAlert! report said, in their research on lung tissue, Peng's team observed green glowing senescent cells "lying next to stem cells on the basement membrane," serving as a barrier that prevents foreign cells and hazardous chemicals from penetrating the body and enables oxygen to diffuse from the air in the lungs into underlying tissues.
The research team saw senescent cells in the same positions in other barrier organs like the small intestine, skin, and colon; and their experiments validated that, if senescent cells were destroyed with senolytics, lung stem cells were unable to correctly repair the barrier surface.
Related information about senescent cells is shown on Mayo Clinic's YouTube video below:
Check out more news and information on Stem Cells in Science Times.
