You have likely heard of stem cells before. Stem cells are special cells that can become any kind of cell. They have huge potential in regenerative medicine, from treating blood cancer to bone and tissue repair. However, you might have also heard that they are difficult to get. Some stem cells come from painful bone marrow harvests, or are collected during pregnancy from embryos, umbilical cords, or placentas. However, there’s one kind of stem cell that is safe, ethical, and non-invasive to access. Stem cells in menstrual fluid.
Menstrual fluid has long been seen as something to hide and throw away. However, science is just beginning to realize that menstrual fluid has huge potential for clinical application, from diagnosing endometriosis to harvesting stem cells. The stem cells that are found in menstrual blood originate in the uterus. The uterus is home to many kinds of endometrial stem cells, such as endometrial mesenchymal stem cells or endometrial epithelial progenitor stem cells. Endometrial mesenchymal stem cells are stem cells that stay in the uterus or are shed in menstrual fluid. Endometrial epithelial progenitor stem cells become epithelial cells, or cells that line surfaces of the body.
All these cells work together to do something amazing. They allow the uterus to completely regrow its inner lining every month during the menstrual cycle, anywhere from 400 to 500 times in a single lifespan. For so long, we never knew the uterus was this amazing! For instance, the liver can regrow after 75% of tissue loss but only once in a while when it needs to respond to injuries. If it keeps regrowing, the liver will scar. Skin cells shed and replace all the time, but not to the extreme organ-wide level that the endometrium sheds and regrows.
Endometrial stem cells found in menstrual blood can differentiate into almost any cell type, a process called pluripotency. Plus, they’re also able to increase in number very quickly and effectively, as well as having low immunogenicity, which means that they are easily “accepted” by the body and less likely to cause an unwanted immune response. Endometrial stem cells can differentiate into adipose or fat cells, glial cells, neurons, pancreatic cells, and bone cells. Scientists have tested endometrial stem cells on all sorts of skin repair, finding that the stem cells are able to support healing. These factors make endometrial stem cells very promising for future use!
In a lab, endometrial stem cells can double every 19.4 hours. They can do this up to 68 times, yielding about 1.5 quintillion cells. That’s enough cells to treat everyone in the world!
Aside from differentiation, endometrial stem cells also have the ability of paracrine signaling. Paracrine signaling is the communication between nearby or local cells, and is made possible when the endometrial stem cells secrete certain chemicals and protein messengers that tell other cells to grow, multiply, move, and ultimately, heal. This means that the stem cells don’t even have to grow at the target area. Instead, all we need is the things that they secrete, such as a nutrient-rich culture broth that is collected from actively growing cells.
There are so many ways to use endometrial stem cells. Scientists have already begun looking at the possible benefits of using these stem cells in treating many conditions, such as intrauterine adhesions (scars inside the uterus), infertility, premature ovarian insufficiency, liver disorders, skin damage, and neurological diseases.
Endometrial stem cells offer huge potential for regenerative medicine. For millions of women and girls with underresearched gynecological conditions, these stem cells offer beautiful promise and hope for better treatments.
Difficult Words:
Endometrium: Pronounced: “en-dow-MEE-tree-umm.” The inner lining of the uterus that is regrown and then shed during the menstrual cycle to prepare for possible pregnancy.
Infertility: Pronounced: "in-fir-TI-luh-tee." Definition: The inability of someone to have a baby.
Menstrual cycle: Definition: The cycle that prepares the uterus for possible pregnancy and takes about 28 days. It is driven by hormones and involves menstruation and the thickening of the endometrium.
Menstruation: Pronounced: “men-STUR-a-tion.” Definition: The process where a woman discharges blood and other materials lining the uterus. This happens about once a month from puberty until menopause. Menstruation stops during pregnancy.
Non-invasive: Pronounced “non-in-VAY-siv.” Definition: Any medical test or procedure that does not involve incisions on the skin or insertion of medical tools.
Premature ovarian insufficiency: Definition: When the ovaries stop working early or before the age of 40. Leads to irregular periods, low estrogen, and infertility.
Uterus: Pronounced: “YOU-ter-us.” Definition: The pear-shaped hollow organ inside a woman’s pelvis. This is where the baby grows, also called the womb.
Sources:
https://pmc.ncbi.nlm.nih.gov/articles/PMC4904135/
https://link.springer.com/article/10.1186/1479-5876-5-57
https://pubmed.ncbi.nlm.nih.gov/30036086/
https://www.mdpi.com/2227-9059/13/10/2435
https://pmc.ncbi.nlm.nih.gov/articles/PMC10797688/