A new study has shown that the bond between mothers and their children may be even more elemental than common wisdom and centuries of art and literature would have us believe. According to Scientific American, new research by the National Institute of Health indicates that mothers’ and children’s cells may integrate into each other’s bodies and remain there, alive, and possibly aiding host tissue in disease resistance and other functions, for decades.
Previously, doctors and scientists have believed that each person’s body was a collection of distinct, individual cells belonging only to ourselves. The discovery of living foreign cells in the body belies that notion and suggests that our bodies may be not only holding on to the cells of others, but putting them to work.
During gestation, mothers and children freely pass cells back and forth via the placenta, where the developing embryo gets all of its nutrients and gases and by which its wastes are processed and eliminated. The embryonic cells can take up residence in multiple locations throughout the mother’s body, including the lungs, muscles, heart, kidneys and skin, as well as in the thyroid gland.
Scientists now say that these cells may have a wide array of impacts on the host tissues. The phenomenon — called microchimerism, after the chimeras of Greek myth, fire-breathing creatures that part snake, part lion and part goat — has even been found in the brain.
In a new study, researchers studied fetal-derived male cells in the brains of some women. The cells were less likely to appear in the brains of women with Alzheimer’s disease, and while a definitive correlation has not been proven, scientists are hopeful of establishing one.
Microchimerism was discovered when scientists found male Y-chromosomal cells circulating in women’s blood after pregnancy, meaning cells from their male offspring were still surviving in their system. Scientists studying Alzheimer’s found Y-chromosomal cells in 60 percent of diseased women’s brains.
Researchers theorized that since Alzheimer’s is more common in women who have had multiple pregnancies, they would find more chimeric feltal Y-chromosome cells in the brains of women with Alzheimer’s. In fact, the reverse was true. There were fewer fetal derived cells in the brains of the women with Alzheimer’s. The scientists are still puzzling out the results.
In addition to passing cells through the placenta, scientists are finding evidence that microchimeric cells are passed from mother to child during nursing, and that twins exchange cells in utero. According to Scientific American, “Women may have microchimeric cells both from their mother as well as from their own pregnancies, and there is even evidence for competition between cells from grandmother and infant within the mother.”
Some evidence suggests that fetal microchimeric cells are like stem cells in that they can become a variety of different types of cells and may aid in tissue repair. Fetal cells in mother rats became new heart or brain tissue according to the mother’s needs.
Other studies show that the cells aid in the formation of important immunities in the mother, possibly preventing the types of mutations that result in cancer. Breast cancer patients, for example, have low levels of fetal microchimeric cells in the blood. Whether scientists are confusing correlation with causation in this instance is still unclear, however.
According to the National Cancer Institute, reproductive history plays a role in whether women are at risk for some cancers. Women who have been pregnant are at lower risk for breast and other types of cancers. While some researchers believe that this has to do with the types of hormones produced during pregnancy, a growing body of evidence indicates that microchimeric cells may play a role in cancer prevention. Babies may protect their mothers in ways they never realized.
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