Mature Cells Activate Hidden Stem Cell Pathways for Tissue Repair, Study

Researchers from Technion-Israel Institute of Technology have discovered that the body possesses an internal repair mechanism that contradicts conventional understanding of tissue regeneration. Rather than aging as permanent and irreversible, mature cells retain the ability to reprogram themselves back into stem cells capable of healing damaged tissue. The findings, published in Nature Communications, suggest that tissue regeneration may not require external cell transplantation.

The prevailing scientific view had held that once stem cells are lost from a tissue, regeneration is no longer possible and disease or collapse follows inevitably. Ruby Shalom-Feuerstein and Shalini Dimri-Wagh challenged this assumption by developing a novel tracking system. Using fluorescent labels in transparent cornea tissue, they monitored stem cell activity in living mice and tested what happens when stem cells are eliminated entirely.

“We were surprised to discover that the cornea can regenerate itself even after the destruction of all its stem cells,” said Prof. Shalom-Feuerstein. “What is even more surprising is the repair process itself. Following injury, even mature, aged cells undergo reprogramming and become stem cells that function throughout life and prevent disease development.”

The researchers determined that this reprogramming is not a temporary response but produces cells that function as stem cells over extended periods, enabling sustained tissue repair. The team identified a driving force behind the process: macrophages, immune cells that normally fight bacterial infections. These cells secrete signaling molecules that trigger the transformation of aged cells into stem cells. 

“In other words, the body has a remarkable ability to replenish its own stem cell reservoir, a capacity usually attributed only to simple organisms that can, for example, regrow amputated limbs,” Shalom-Feuerstein explained. “While the ability to regenerate entire organs was indeed lost in complex organisms such as humans, our study shows that part of this capacity remains. This means that instead of relying solely on transplants or external interventions, we may one day be able to activate natural mechanisms that already exist within the body and harness them for healing.”

The findings hold significant potential for clinical applications, particularly in tissues like the cornea, where stem cell damage causes vision loss and blindness. Although the research was primarily conducted in mice, results from human corneal cells are promising. The team emphasizes this is an initial step toward understanding a previously unknown natural process and are now working to determine whether the mechanism exists in humans and can be controlled for therapeutic purposes.