SC Connecticut News

Stem cells play a crucial role in repairing damaged tissue, whether it’s a scraped knee or a scarred uterus following pregnancy. New stem cell research has identified the molecules that the cells produce to promote the healing process. The finding could pave the way for the development of new, more effective drugs for injuries or various diseases, including conditions related to reproductive health such as Asherman syndrome, a gynecologic condition in which the uterus scars and becomes fibrotic.

Scientists previously believed that stem cells served as backup cells that repaired tissues by differentiating into new cells that repopulated the site of injury. Now, they have learned that it is rare for stem cells to completely replace injured tissue. However, they still do not fully understand how the cells are able to help damaged areas regenerate.

"We found the molecules that stem cells make to help heal and repair tissue, and we hope that understanding this will be potentially useful as a medication in the future," says Hugh Taylor, MD.

In the uterus, stem cells play several roles, including helping it expand during pregnancy and regenerate after childbirth. This new study identified several microRNAs (miRNAs) secreted by stem cells that helped drive growth and proliferation of cells in uterine tissue. The researchers published their findings in Stem Cell Research & Therapy on May 1.

Exosomes are extracellular vesicles containing various bioactive molecules and allow cellular communication. In their study, Taylor’s team isolated exosomes secreted by stem cells from human bone marrow. They used RNA sequencing to characterize all miRNA contained in these vesicles and identified those most abundant. Researchers then introduced these prominent miRNAs into human uterine tissue.

The team found that miRNAs significantly increased growth and proliferation of uterine cells. They also studied their effect on decidualization in endometrial cells—a differentiation process preparing the uterus to support an embryo—and discovered that miRNAs blocked decidualization.

"In a uterus, once a cell becomes differentiated to support pregnancy, it can no longer repair and regenerate," explains Taylor. "By blocking this process, it allows the cells to focus on proliferating and turns on these reparative processes."

The study offers insight into how stem cells promote reparative processes without replacing tissue itself. Taylor hopes that as researchers gain greater understanding about how miRNAs work, they could one day be used as drugs for repairing various damaged tissues.

Asherman syndrome typically occurs after pregnancy when there may not be enough stem cells available to help heal properly, potentially hindering future fertility. "The idea is that these miRNAs could be used as a medication much more readily available and practical," says Taylor. "We could potentially deliver them to help prepare the uterus in critical windows when it is damaged and may be vulnerable."

The finding could also have significance beyond reproductive health. In future research, Taylor’s team plans to study how miRNAs respond to other types of traumatic tissue injury in animal models.

"We studied the uterus," notes Taylor, "but the implications are beyond reproduction—potentially including many other conditions where stem cells are involved in repair and regeneration."