Microchimerism: cells of others living in our body

Most of us know that during pregnancy the mother passes different substances such as food and oxygen to the fetus. They allow them to feed themselves and survive. In this transmission, the fetus receives cells from the mother, which are involved in its survival, growth and maturation. But since the late 1990s, it has been detected that the transmission of genetic information is not one-way, but it is possible to see that the baby’s cells also pass and interact with those of the mother in the body of the baby. this one. In other words, something called microchimerism occurs.

    Micochimerism: cells in an alien body

    The concept of microchimerism refers to that situation in which a person or creature he has cells of other individuals in his body, Have inside a small percentage of DNA different from yours. These cells establish a relationship with the subject’s genetics, and can create a link between the two types of cells, which has both positive and negative consequences.

    Microchimerism occurs in both humans and other animal species, Such as rodents or dogs. It is a mechanism that has probably been around for millions of years, although it was discovered at the end of the last century.

    Natural microchimerism

    Although the first indications of this phenomenon were discovered thanks to the realization of transplants in animals, the microchemistry which occurs most often in nature between two multicellular organisms is that occurs during pregnancy.

    During pregnancy, mother and child are connected by umbilical cord and placenta, and through this connection they exchange certain cells that pass into each other’s body and become integrated there. It is suspected to have a higher incidence than previously thought and some experts even consider it to occur in all pregnancies. Specifically, it was found that they were already from the fourth week of gestation fetal cells can be found in the maternal body, And it is generally considered that from the seventh week can be identified in all pregnancies.

    This relationship between mother and child cells is not transient and is lost a few months or years after childbirth: the presence of child cells in the mother’s body has been observed up to more than twenty years after childbirth. These cells grow throughout the body, are found in the heart, liver, or even the brain, and interact with the subject’s own cells.

    Cells of the other organism they fit into their own structures and fabrics, Including the nervous system. Different experts have questioned the effect that these cells can have on behavior, and it can also be associated with the emergence of affection between mother and child. One could speculate that part of one’s own DNA is in the other may imply a higher rate of protection at the behavioral level, generating a higher level of bonding and the perception of greater similarity.

    It is important that the pregnancy does not even have to be successful for this cellular exchange to take place: even in women who have lost their babies the existence of cells with different DNA was found, which seems to correspond to that of the baby.

    Studies to date have generally been carried out on mothers who have given birth to male children. It’s not that microchimerism doesn’t occur between mother and daughter, but it’s much easier to locate cells with sex chromosome I on a female body instead of trying to differentiate two XX cells.

      Effects on the mother

      It may be logical to think that in the interaction that takes place between mother and child, it will be the mother’s cells that will provide beneficial effects to the baby, because the mother’s body is already formed and that of the mother. mother. . But the truth is that the transmission of cells from the baby to its mother too it can have big effects on your health.

      It has been shown, for example, that fetal cells often help heal internal wounds and injuries, as well as reduce symptoms of disorders such as pain in osteoarthritis both during pregnancy and in the long term. It also improves the immune system and facilitates the development of future pregnancies.

      It has also been proposed that the presence of these cells may help explain why women have greater endurance capacity and longer life expectancy, noting that many women who had given birth and possessed these microchemical cells generally have a better life expectancy (possibly due to an improvement in the autoimmune system, although this is currently only speculation). It has also been found to reduce the likelihood of cancer and that they tend to participate in tissue regeneration, Observing its implication in the cure of heart or liver diseases.

      However, microchimerism can also be negatively affected. It has been observed that the immune system of some women reacts to these cells as if they were invaders, linking them to the onset of certain autoimmune diseases. These are more common in the mother than in the fetus. They could also be linked to certain types of cancer, Although its very existence is a protective factor against this type of disease.

        Effects on the baby

        The transmission of stem cells makes the body of the unborn baby very important to him. Interestingly, it is the microchemistry that has received the least attention, focusing more on the effects of this transmission on the mother. One likely explanation for this is the difficulty of establishing differences between what the organism itself and the subject’s cells do per se and the specific influence of stem cells.

        It has been detected that the presence of stem cells in the body of the son or daughter, for example, helps children with diabetes to fight his condition. On the other hand, this transmission has also been linked to the onset of diseases such as severe immunodeficiency, neonatal lupus syndrome, dermatomyositis and biliary atresia.

        acquired microchimerism

        As we have indicated, microchemistry occurs naturally during pregnancy, this is the main form of microchemistry that exists but in addition to this process, it is possible to find this phenomenon in other types of situations, be able to speak of an acquired microchimerism.

        We are talking about organ and tissue transplants or blood transfusions, in which a part or product of one organism is inserted into another. The donated blood or organ contains the donor’s DNA, which enters and it interacts with the subject’s body that this organ receives. In this case, the relationship is not symbiotic between the individuals, as it is the recipient of the donation who receives the advantages and disadvantages of this phenomenon.

        However, this type of microchemistry has its risks, just like the body. he can recognize alien DNA as something outside invading him and react by attacking, resulting in rejection of the organ, tissue or blood. That is why it is important to take into account the blood group and donor-recipient compatibility, as well as the use of drugs to prevent such rejection from occurring.

        For this, the administration of drugs which reduce the role of alloreactive T lymphocytes (i.e. lymphocytes which react to the presence of DNA other than the same) should be used, in order to facilitate the emergence of tolerance of the graft. One common way to do this is to inhibit the replication of these lymphocytes.

        Bibliographical references:

        • Carter, A. and Fuggle, S. (1999). Detection of microchimerism after blood transfusion and solid organ transplantation: a delicate balance between sensitivity and specificity. Transplant Reviews, 13, 98-108.
        • Khosrotehrani, K .; Johnson, KL; Cha, DH; Salomon, RN and Whites, DW (2004). Transfer of fetal cells with multilinear potential to maternal tissue. Journal of the American Medical Association 292 (1): 75-80.
        • Quirós, JL and Arce, IC (2010). Natural microchimerism Are there humans with multiple genomes? Bibliographic review. Costa Rican Forensic Medicine, 27 (1). Heredia, Costa Rica.
        • Rodriguez-Barbosa, JI; Domínguez-Perles, R .; from the river, ML; Peñuelas, G .; Valdor, R .; Police, C .; Muñoz, A .; Ramírez, P .: Pons, JA and Parrilla, P. (2004). Induction of tolerance during solid organ transplantation. Gastroenterology and Hepatology, 27 (Suppl. 4): 66-72. Elsevier.
        • Rowland, K. (2018). We are crowds. Eó.

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