There is no doubt that pregnancy is an incredible time in a woman’s life. It is also a time of major changes for her body. As her baby grows, her body makes many adjustments, both externally and internally. And while many of the changes are ones we can see, a new study looks at the cellular ways our bodies “remember” the experience.
Published online September 21, 2023, the journal Science reveals that the connection between a mother and her developing fetus is even more complex and long-lasting than previously thought. While scientists have long understood that the mother’s body adapts to prevent her immune system from attacking the fetus, this new research sheds light on the cellular discord that takes place between a mother and her offspring.
Conducted by Sing Sing Way, MD, PhD, Division of Infectious Diseases at Cincinnati Children’s and the Center for Inflammation and Tolerance, it explores how past pregnancies affect future pregnancies and how mothers remember their babies. The findings provide valuable insights into maternal resilience, which can help reduce the risk of complications in subsequent pregnancies.
“By investigating how previous pregnancy changes the outcomes of future pregnancies—or in other words, how mothers remember their babies—our findings add a new dimension to our understanding of how pregnancy works,” says Way. “Nature has designed built-in resilience in mothers that generally reduces the risk of preterm birth, preeclampsia and stillbirth in women who have a previous healthy pregnancy. If we can learn ways to mimic these strategies, we may be better able to prevent complications in high-risk pregnancies.”
Understanding how the immune system changes during pregnancy not only has implications for improving outcomes in high-risk pregnancies, but also has the potential to advance research into vaccine development, autoimmunity and the prevention of transplant rejection. instruments.
In a previous study published in Nature in 2012, Way and his colleagues found that a woman’s body is less likely to reject a second pregnancy by the same father after a first pregnancy. This phenomenon is attributed to the presence of immunosuppressive T cells that are specific for the future fetus and instruct the immune system to cooperate with the pregnancy. These cells remain in the mother’s body for years after giving birth.
“Very small numbers of fetal cells can be found in the heart, liver, intestine, uterus and other tissues,” says Way. “The fact that we are made up of more than just cells with our own genetics, but also cells from our mothers and children is an exciting idea.”
This research revealed that the longevity of these memory-suppressing T-cells is mediated by fetal microchimeric cells, a small population of infant cells that remain in the mother’s body after pregnancy. This biological evidence confirms a more special relationship between mothers and children than previously known.
While it was initially surprising to find these suppressor cells persisting postnatally, it is believed that the presence of fetal microchimeric cells is responsible for maintaining the protective memory response. The researchers also noted that the presence of maternal microchimeric cells transferred to the child during pregnancy may contribute to the success of organ transplants from mothers.
The interaction between microchimeric cells raises interesting questions about their interactions and accumulation thresholds. Each person can have only one set of microchimeric cells at a time, and these cells are replaced by new fetal cells in subsequent pregnancies. However, mothers retain a small number of suppressor T cells from each pregnancy, which act as a safety mechanism and can be called into action during future pregnancies.
This interesting research deepens our understanding of the complex relationship between mothers and their babies and may lead to new strategies to prevent complications in high-risk pregnancies. In addition, it paves the way for further advances in areas such as vaccination, autoimmunity and organ transplant research.
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