Thursday , January 21 2021

An atlas describes how the female's immune system adapts to the embryo during pregnancy



Every minute 250 babies are born in the world. For their families it is an extraordinary event. For researchers, birth is the result of a fact that implies a captivating paradox: The woman's immune system is dedicated to defending it against the invasion of viruses, bacteria, fungi, among others, but it allows the development of a fetus, That contains genetic material from another person. Now, researchers from England, Spain and Germany have performed for the first time The atlas of the cells that is in the contact zone between the placenta and the woman in the first months of pregnancy. In this way, they confirmed the existence of molecular mechanisms that make the female immune system "friend" to the fetus's presence.

the atlas with 35 cell types It was published by researchers in a journal work nature of the UK. They received it from studying 70,000 white blood cells and cells from the placenta and decidua (the layer formed in the pregnant uterus), derived from women whose pregnancies ended between weeks 6 and 14 of the pregnancy, who gave their consent in writing.

The identification of these cell types and the molecular mechanisms that arise in the interaction between the mother's immune system and the fetus gives greater knowledge to understand the causes of various problems that may occur during pregnancy. "One can say there are several mechanisms to ensure a friendly environment between fetal and mother cells," he said. Infobae The first author of the work, the Spanish biotechnologist Roser Vento-Tormos, who is postdoctoral in the laboratory of scientist Sarah Teichmann at the Sanger Institute in Cambridge, United Kingdom.

Days after the egg is attached to the sperm cells blastocyst, which is implanted in the woman's uterus. Placenta is also formed in the decidua, which is the mucous membrane that covers the uterus transiently. That makes the fetal and mother cells contact. Traditionally, it was estimated that the fetus was like a graft inside the woman, but thanks to research in the field of pregnancy immunology, everything changed. Atlaset – also performed by researchers from YDEVS Software Development in Valencia, Spain, Cancer Research Center in Heidelberg, Germany and the universities of Cambridge and Newcastle, England – involved another step in that address.

"In our study, we observed that cells in the layer encounter placenta-express immunomodulating molecules, and therefore, reduce any type of inflammation that may occur upon the invasion of fetal cells it forms the basic structure of the placenta and it invades the uterus, "said Vento-Tormos.

The fetus has its own cells that help the mother's immune system not attack it. They are the trophoblasts, which are the main components of the placenta. "In one of the differentiation paths, the trophoblasts differentiate and invade the decidua and go to the arteries, replacing the mother's endothelial cells and swelling the arteries, which is essential for increasing blood flow. Against the placenta, and therefore the change of nutrients between the fetus and the mother. On their way they will meet with the mother's immune cells and communicate with them. This very specific communication, which we describe in detail in our article, contributes to the fact that fetal and maternal cells exist in the same environment. In fact, our study indicates that the immune system may be necessary for the necessary invasion of trophoblasts, "said Vento-Tormos.

With the atlas, we sought to "see all the cells found in the micro-environment and how they" talk "to each other." I do not like to use the word "tolerate" as the immune system is not sleeping. The maternal immune system is active and has specific functions like helping to rearrange the arteries or help the fetal trophoblasts into the tissues and go to the arteries. There is a specific communication between trophoblasts and the mother's immune cells, so both cells interact peacefully, "said the Spanish scientist.

"At the moment there is great interest in knowing what the brokers are and the mechanisms of" dialogue "or interaction between the placenta and the mother's immune system at the beginning of pregnancy. Understanding these mechanisms at cellular and molecular levels could contribute to the development of Early treatments for pregnancy complications diagnosed at the end of pregnancy, such as pre-eclampsia and embryo growth, which can have serious consequences for mother and neonatal health, "he said. Infobae Physician in Chemistry Claudia Pérez Leirós, Principal Researcher of Conicet at the IQUIBIC, Faculty of Science at the University of Buenos Aires, who together with Dr. Rosanna Ramhorst leads a research group specializing in reproductive immunology. Pre-ectopic disorder can affect up to 5% of pregnant women, it changes blood pressure and causes 76,000 women a year in the world (25% of these deaths occur in Latin America).

"Atlas published in the magazine nature It is very valuable, "said Dr. Pérez Leirós. Describes the different cell populations present in the maternal fetal interface at the beginning of pregnancy and indicates their possible interactions through a new technology to study RNA cells at the individual level, which is called transcriptomics and bioinformatic analysis. As the authors shared the data obtained in a public archive, this wealth of information will certainly be used by researchers from other laboratories and will help speed up studies related to pregnancy and associated pathologies. "

In addition to pathologies related to pregnancy, atlas in the first trimester of pregnancy could also provide a way to better understand what happens to the immune system when the body receives an organ transplant from another person or when tumors develop. "The environment during pregnancy and cancer has similarities," said Roser Vento-Tormos. "In both scenarios, cells with different DNAs exist. Cancer cells are different due to mutations that accumulate in DNA. Nevertheless, they have mechanisms to evade the immune response, similar to those found with fetal trophoblasts. In this environment, we have detected the presence of immune control point inhibitors similar to those present in cancer. "


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