Babies’ Cells Found in Mothers’ Brains!

Scientists have known for years that during pregnancy, cells from the developing fetus can wind up in the mother’s bloodstream. But a newer study shows that fetal cells can also travel to specific organs, such as the heart, lungs, skin … and even the brain, where they can become integrated among the mother’s neuronal cells permanently.

This process is known as “microchimerism.” (The name comes from Greek mythology, in which Chimera was a creature that was part serpent, part lion and part goat.) Microchimeric cells were first noticed in humans when cells containing the male Y chromosome were found in the blood of mothers after a pregnancy (these foreign cells can live in the mother’s bloodstream for years after a pregnancy).

Cells traveling from the fetus to the mother’s brain and other organs had only been seen in mice. But this recent study found that cells from human fetuses can also travel to maternal organs.

Researchers at the Fred Hutchinson Cancer Research Center in Seattle analyzed tissue from 59 autopsied female brains. The scientists found Y-chromosome genes in 63 percent of the brains, and in different regions of the brains. In some cases, the cells had been there for several decades.

The cell transfer between mother and fetus occurs through the placenta, an organ that is built of cells from the mother and the fetus, and serves to exchange nutrients, gasses and wastes.

Chimeric cells are an emerging field of research, and many questions remain to be answered, including what the possible functions, if any, might be for these cells.

One of the special characteristics of chimeric cells is that they have the ability to become different tissues, like stem cells, and that’s how they’re able to inhabit different parts of the body.

Past research with rats showed cells from the fetus migrated to the mother’s heart when the heart had been injured. The fetal cells targeted the injured area, where they became several types of cardiac cells and helped repair the tissue.

We do not yet know whether the human fetal cells that go to the mother’s brain and become neurons actually become functional. However, researchers did find fewer chimeric cells in the brains of mothers who had had Alzheimer’s disease at the end of their lives than in the brains of mothers who had not had Alzheimer’s. And other studies have shown that many more microchimeric cells are found in the blood of healthy women than in that of women with breast cancer. This prompts researchers to theorize that fetal chimeric cells may have a protective function for the mother’s tissues.

But whether chimeric cells are necessarily beneficial is not yet known. Indeed, some studies have linked the prolonged existence of fetal cells in the mother’s blood to autoimmune disease. One study showed that the numbers of fetal cells were higher in women who had multiple sclerosis, an autoimmune disease, compared to siblings of these women who did not have the illness. This has led some researchers to speculate that the increase we’ve seen in autoimmune disorders among women in the last 40 years could be linked to the increase in abortion rates. When the placenta is destroyed during an abortion, a higher number of chimeric cells transfer into the mother’s bloodstream.

Pro-life groups are using these latest findings as another argument against abortion. And while the precise roles that chimeric cells may or may not play will continue to be investigated, one thing that’s clear is that they attest to just how deeply interconnected a mother and her baby are, even after birth.

By Jamell Andrews