Fetal Cell Microchimerism; Normal and Immunocompromised Gestations in Mice

Presence of fetal DNA in maternal exhaled breath condensate

OBJECTIVES

Cell-free DNA has been found in all body fluids, but DNAs emerging from locations that are not in direct contact with breath in exhaled breath condensate (EBC) are yet to be found. The potential of EBC for prenatal and cancer screening prompted us to investigate whether fetal DNA is present in maternal EBC.

METHOD

A total of 20 pregnant women's EBC and blood samples were collected. Four Y chromosome-specific assays were tested on all EBC and plasma samples by quantitative PCR (qPCR). The best-performing assay was used for digital droplet PCR (ddPCR) on all EBC and the six plasma samples.

RESULTS

The sex of the fetuses was accurately determined from plasma samples. DNA sequences could not be properly amplified in EBC samples by the qPCR. By ddPCR, the Y chromosome sequence was amplified in two of the 11 EBC samples, from women carrying male fetuses (2/11), and the Y chromosome sequence was not amplified in the EBC of women carrying female fetuses (9/9). Exhaled breath condensate ddPCR result's specificity was 100%, the detection rate of Y chromosome was 18.18% (2/11), and the corrected accuracy was 59.09%.

CONCLUSION

Our finding of "the presence of fetal DNA in maternal EBC", despite the low detection rate, might have a major impact on prenatal diagnosis and cancer screening.

Do Fetal Microchimeric Cells Influence Experimental Autoimmune Myocarditis?

Objective: We investigated the presence and influence of fetal microchimerism in the cardiac tissue of mated female mice submitted to experimental autoimmune myocarditis. Materials and methods: Nulliparous BALB/c females and BALB/c females mated with either BALB/c males (syngeneic mating) or C57BL/6 males (allogeneic mating) were immunized with cardiac myosin peptide MyHC-α_614-629 or kept as non-immunized controls. Immunization occurred 6-8 weeks after delivery and mice were assessed after 21 days. Results: Immunized mice of allogeneic mating had a lower production of anti-MyHC-α_614-629 antibodies compared to immunized nulliparous mice. Immunized nulliparous females had an intense mononuclear inflammatory infiltrate in cardiac tissue, associated with fibroplasia, while mated females had a lower inflammatory reaction. An increase in the frequency of microchimeric fetal cells was observed in mice submitted to allogeneic mating following immunization. Conclusion: Allogeneic cells of fetal origin could contribute to mitigating the inflammatory response in experimental myocarditis.

Feto-maternal microchimerism: Memories from pregnancy

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.