A living connection
Image: ock / Анастасия Попова
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The link between a mother and child is profound, and new research suggests a physical connection even deeper than anyone thought. The profound psychological and physical bonds shared by the mother and her child begin during gestation when the mother is everything for the developing fetus, supplying warmth and sustenance, while her heartbeat provides a soothing constant rhythm.
The physical connection between mother and fetus is provided by the placenta, an organ, built of cells from both the mother and fetus, which serves as a conduit for the exchange of nutrients, gasses, and wastes. Cells may migrate through the placenta between the mother and the fetus, taking up residence in many organs of the body including the lung, thyroid muscle, liver, heart, kidney and skin. These may have a broad range of impacts, from tissue repair and cancer prevention to sparking immune disorders.
It is remarkable that it is so common for cells from one individual to integrate into the tissues of another distinct person. We are accustomed to thinking of ourselves as singular autonomous individuals, and these foreign cells seem to belie that notion, and suggest that most people carry remnants of other individuals. As remarkable as this may be, stunning results from a new study show that cells from other individuals are also found in the brain. In this study, male cells were found in the brains of women and had been living there, in some cases, for several decades. What impact they may have had is now only a guess, but this study revealed that these cells were less common in the brains of women who had Alzheimer’s disease, suggesting they may be related to the health of the brain.
We all consider our bodies to be our own unique being, so the notion that we may harbor cells from other people in our bodies seems strange. Even stranger is the thought that, although we certainly consider our actions and decisions as originating in the activity of our own individual brains, cells from other individuals are living and functioning in that complex structure. However, the mixing of cells from genetically distinct individuals is not at all uncommon. This condition is called chimerism after the fire-breathing Chimera from Greek mythology, a creature that was part serpent part lion and part goat. Naturally occurring chimeras are far less ominous though, and include such creatures as the slime mold and corals.
Microchimerism is the persistent presence of a few genetically distinct cells in an organism. This was first noticed in humans many years ago when cells containing the male “Y” chromosome were found circulating in the blood of women after pregnancy. Since these cells are genetically male, they could not have been the women’s own, but most likely came from their babies during gestation.
In this new study, scientists observed that microchimeric cells are not only found circulating in the blood, they are also embedded in the brain. They examined the brains of deceased women for the presence of cells containing the male “Y” chromosome. They found such cells in more than 60 percent of the brains and in multiple brain regions. Since Alzheimer’s disease is more common in women who have had multiple pregnancies, they suspected that the number of fetal cells would be greater in women with AD compared to those who had no evidence for neurological disease. The results were precisely the opposite: there were fewer fetal-derived cells in women with Alzheimer’s. The reasons are unclear.
Microchimerism most commonly results from the exchange of cells across the placenta during pregnancy, however there is also evidence that cells may be transferred from mother to infant through nursing. In addition to exchange between mother and fetus, there may be exchange of cells between twins in utero, and there is also the possibility that cells from an older sibling residing in the mother may find their way back across the placenta to a younger sibling during the latter’s gestation. 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.
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31 Comments
Add Comment"... may have a broad range of impacts, from tissue repair and cancer prevention to sparking immune disorders."
Reply | Report Abuse | Link to thisI have to wonder then do mothers statistically outlive women who have never been pregnant? Has this question ever been studied?
More on this topic at http://www.scientificamerican.com/article.cfm?id=your-cells-are-my-cells
Reply | Report Abuse | Link to thisMaybe this is the way how unconscious memory (instincts) or sometimes even conscious memories are transferred? Our own and all ancestors lifetime experiences reside somewhere inside us, and the only possibility to store such big amount of information I see in the chemistry inside cells, neurons or some other kind.
Reply | Report Abuse | Link to thisMaybe my theory that Déjà vu is really memory cells from an ancestor isn't so far fetched.
Reply | Report Abuse | Link to thisI agree...
Reply | Report Abuse | Link to thisYes. And those that have a child (not necessarily the first) after 35 have been shown to live the longest. The research can be found online. There are websites for late term mothers that publish links to these studies. The Mayo clinic has done at least one.
Reply | Report Abuse | Link to thisHello JustLooking and JT-----you 2 are obviously on to something. The obstetric literature is replete with studies showing that women who have never had a child have a higher incidence of both breast and ovarian cancers. It's the continuous monthly cycling that causes these mutations. Nature's way is for the woman to be more or less constantly pregant or at least breast feeding which itself would interrupt the monthly cycyles. So, you see there are many variables and the famous Minnesota Twin Study might have some further elucidation. In that study identical twins were separated at birth and were reunited later. The similarities are fascinating and, some, beyond belief.
Reply | Report Abuse | Link to thisA transfering of cells would have zilch to do with 'deja vu'. It's not how neurons work. That concept is more the outcome of cheesy 1930 novels.
Reply | Report Abuse | Link to thisDid they also study the brains of men? Maybe foreign cells can migrate there from other sources, such as nucleated cells from blood transplants. Maybe the foreign cells in women aren't really coming from fetuses. Were they genetically matched?
Reply | Report Abuse | Link to thisCurious: What is the likelihood of this CAUSING a mental or physical disease in the mother that has had no previous symptoms or family history of that particular illness yet develops it years later after carrying a child that had inherited the disease from the other parent?
Reply | Report Abuse | Link to thisThis experimental evidence argues in favor of my intuition that women are biologically superior to men. I wouldn't be surprised if eventually we men disappear as a viable species. Male rabbits can reproduce parthenogenetically with no need for male sperm participation. Can this fact be extended eventually to include human females? Quare Some years ago I wrote a medical malpractice fiction in Spanish (Las Empresas Montero) where this actually happened. Sorry for the commercial but you can read it at
Reply | Report Abuse | Link to this<http://www.lulu.com/shop/search.ep?keyWords=Dr.+Angell+O.+de+la+Sierra&categoryId=100501&pn=3> :-) Dr.d
this leads me to wonder if a few 'y' cells injected into a woman with Alzheimers, (from her husband), might slow, or defeat the disease.
Reply | Report Abuse | Link to thisThis makes me wonder if a few 'y' cells from a male (husband), or son, might cause a withdrawai from Alzheimers
Reply | Report Abuse | Link to this[...], taking up residence in many organs of the body including the lung, thyroid muscle, liver, heart, kidney and skin[...]
Reply | Report Abuse | Link to thisAs far as I know, there is no such thing as a thyroid muscle. I suppose this is only because of a missing coma, but please correct it as it brings confusion.
This is very interesting...while my wife is a very awesome person, she is really not a humerous person.
Reply | Report Abuse | Link to thisBut - when my wife was pregnant with our 2nd child I kept telling her how funny she was. As soon as she had our son, it ceased.
He has a very unique sense of humor and I always tell that story - we really knew he was going to be a funny guy from BEFORE the time he was born.
This is very interesting...while my wife is a very awesome person, she is really not a humerous person.
Reply | Report Abuse | Link to thisBut - when my wife was pregnant with our 2nd child I kept telling her how funny she was. As soon as she had our son, it ceased.
He has a very unique sense of humor and I always tell that story - we really knew he was going to be a funny guy from BEFORE the time he was born.
The mother's with multiple births & Alzheimers probably have less microchimeric cells in their brain because these cells have been recognized by their immune system as foreign & destroyed. Perhaps in the process, the resulting inflammation & destruction leads to damage in the brain (abnormal amyloid accumulation) resulting Alzheimers. Mothers having immune systems that do not recognize these cells as foreign, probably are able to derive a benefit form these cells peacefully co-existing within. Their additional genetic contribution potentially expressed in a biological complimentary manners- ie., providing additional immunological recognition/ or repair reconnaissance- perhaps even affecting intelligence and mental health.
Reply | Report Abuse | Link to thisI was wondering that as well. They just said they found male cells in the brains of women who had been pregnant. They didn't even say whether or not any of the children had been male.
Reply | Report Abuse | Link to thisThey did say it seemed the transfer could go the other way & through siblings, as well, perhaps some males were included in that part of the study?
There are a lot of unanswered questions here.
Why be so quick to dismiss deja vu as the "outcome of cheesy 1930s novels"? As the Chinese say, "A closed mind is like a closed book--just a block of wood."
Reply | Report Abuse | Link to thisAt what point in pregnancy does the cell migration begin? Could mothers be carrying cells of, say, previous miscarriages?
Reply | Report Abuse | Link to thisIs it possible that Alzheimer's could be a result of the body attacking the foreign cells in the brain? It kills the cells but also causes the normal brain cells to deterioriate?
Reply | Report Abuse | Link to thisIt would be very difficult to relate the mother's lifetime with the presence of these cells. I don't find this research surprising. Everyone has stem cells inside them, and we already know that they home to sites of injury/inflammation.
Reply | Report Abuse | Link to thisYou are on a scientific site so you should know the proper application of "who" and "that".
Reply | Report Abuse | Link to this"The connection between mother and child is ever deeper than thought."
Reply | Report Abuse | Link to thisClever!
Any evidence of maternal cells residing in their sons? X-chromosome containing cells should be detectable in male offspring in that case.
Reply | Report Abuse | Link to this"however there is also evidence that cells may be transferred from mother to infant through nursing"...
Reply | Report Abuse | Link to thisno wonder why Breast-feeding reduces cancer risk..
one thing they did say is that cells from different people inside the mother will compete with each other. perhaps that is why the effects of pregnancy can be good for cancer but bad for autoimmune disorders. maybe having children is good for the mother, but better if she has less of them. i read the entire article, but didn't find anything about number of children versus benefits and drawbacks.
Reply | Report Abuse | Link to thisConsidering the possibility of such cells "priming" the immune system, I wonder if this helps to drive genetic diversity. People who's parents are more genetically dissimilar would have a better primed immune system.
Reply | Report Abuse | Link to thisMy mother had seven children and later developed breast cancer resulting in a double masectomy.
Reply | Report Abuse | Link to thisMy wife's mother had 5 children (all girls) and developed severe Alzheimers in her early 70's.
The situation is far, far more complex than suggested in the article.
I was thinking the same thing, thanks for posting this, as I was hesitant to sound too new-agey on a "Sci Am" post.
Reply | Report Abuse | Link to thisCheck this out - it is amazing on shared memory and consciousness. Be patient with the transcript from that wonderful show, To The Best of Our Knowledge. Here is the link: http://ttbook.org/book/transcript/transcript-darold-treffert-uncut. It's so intriguing along the lines of the shared cell discoveries.
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