Feto-maternal microchimerism: Memories from pregnancy

Abstract

Summary There is a bidirectional transplacental cell trafficking between mother and fetus during pregnancy in placental mammals. The presence and persistence of fetal cells in maternal tissues are known as fetal microchimerism (FMc). FMc has high multilineage potential with a great ability to differentiate and functionally integrate into maternal tissue. FMc has been found in various maternal tissues in animal models and humans. Its permanence in the maternal body up to decades after delivery suggests it might play an essential role in maternal pathophysiology. Studying the presence, localization, and characteristics of FMc in maternal tissues is key to understanding its impact on the woman’s body. Here we comprehensively review the existence of FMc in different species and organs and tissues, aiming to better characterize their possible role in human health and disease. We also highlight several methodological considerations that would optimize the detection, quantification, and functional determination of FMc.

Increased fetal microchimerism in immune and stem cell subsets in preeclampsia

“…This may reflect the increased frequency of circulating stem cells in the fetus compared to adults 58 . Human and animal studies have demonstrated that pluripotent FMc participate in the process of inflammation and wound healing 59–62 . The presence of substantial FMc in stem cells suggests a mechanism for long term maintenance of FMc which may provide a mechanism for the maintenance of pro‐ or anti‐inflammatory programing.…”

Adopted neoplastic cells and the consequences of their existence

“…A hint that neoplastic adoption is not limited to transplant patients comes from the studies of fetomaternal microchimerism, a condition in which cells exchanged between a woman and her child during pregnancy persist in their bodies, sometimes for decades [194][195][196]. If the fetus is a male, fetal cells can be identified in the mother's tissues by visualizing the Y chromosome, the same approach that was used to look for cell hybrids in transplant patients.…”

Foetal microchimerism occurs in pigs

“… 1 This results in the presence of maternal cells in the foetal circulation, a condition known as maternal microchimerism (MMc), as well as foetal cells in the maternal circulation, a condition known as foetal microchimerism (FMc). 2 …”

“…1 This results in the presence of maternal cells in the foetal circulation, a condition known as maternal microchimerism (MMc), as well as foetal cells in the maternal circulation, a condition known as foetal microchimerism (FMc). 2 In 1893, Georg Schmorl initially reported FMc, when he discovered placental trophoblast cells in women who died of eclampsia. 3 Foetal cells are now well proven to enter the maternal bloodstream throughout both human and rodent gestations.…”