Did you know that during pregnancy, if a mother suffers organ damage, the fetus in the womb sends stem cells to repair the damaged organ?
The fetal stem cells can persist in the mother for decades after pregnancy without rejection. The cells can be engrafted into the maternal bone marrow and migrate through the circulation despite the cells having distinctly different genetics.
During pregnancy, there’s a transfer and incorporation of the fetus’ stem cells into its mother’s organs, called fetomaternal microchimerism. The fetal stem cells can persist in the mother for decades after pregnancy without rejection. The cells can be engrafted into the maternal bone marrow and migrate through the circulation despite the cells having distinctly different genetics.
Stem cells can morph into different tissues. In a trial done on clinical mice by Dr. Hina Chaudhry of the Mount Sinai School of medicine in New York City and her team, female mice were mated with transgenic male mice tagged with a fluorescent protein. When monitored, the fetal stem cells flowed from the mother’s placenta into the mother’s heart when they induced cardiac injury to the mother. The fetal stem cells directly targeted the damaged cardiac cells and were integrated into the mother’s heart.
According to Chaudhry, it is an evolutionary mechanism. The fetus promotes its survival by protecting its mother’s heart. The cells cannot cause any immunological reaction because they are obtained from the placenta and are likely to provide a new and potentially limitless source of stem cells that repair damaged hearts.
However, in a review on the topic, Amy Boddy, a postdoctoral fellow at the Arizona State University, wrote that the process is bidirectional. The mother’s cells also cross the placenta into the fetus. According to this review, we all carry our mothers’ cells and are closer to our older siblings than we’d imagine.