04 Dec Study Refutes “Sterile Womb Dogma”: How the Cold Virus Can Spread to Fetus from Mother

MedicalResearch.com Interview with:

Dr. Piedimonte

Giovanni Piedimonte, MD, FAAP, FCCP
Vice President for Research
Institutional Official
Professor of Pediatrics
Tulane University

MedicalResearch.com: What is the background for this study?

Response: We have been testing the hypothesis that, when a pregnant woman catches a common cold with a virus called respiratory syncytial virus (RSV), viral particles can spread from the mother’s respiratory tract to the unborn child via the placenta. Preliminary data in animal models suggest that this is possible, and might cause changes in lung growth predisposing the offspring to develop asthma after birth. Recently, also human data have supported this theory.

However, an essential step to conclusively demonstrate vertical transmission of respiratory viruses was the confirmation that human placentas can be infected and allow the transmission of such germs, which is the main finding of this study.

MedicalResearch.com: What are the main findings?

Response: Unexpectedly, we also found evidence that RSV uses to access the fetus an approach very similar to that putatively used by the completely unrelated Zika virus, i.e., infects and accumulates within the placental immune cells that should instead protect the fetus against the invasion of germs and other environmental particles.

MedicalResearch.com: What should readers take away from your report?

Response: For many years, the placenta was perceived as a perfectly secure gate between the mother and the fetus, protecting the latter from environmental influences because impenetrable to most physical, chemical, and biological agents.

Hence, most previous studies exploring the effects of respiratory viruses or pollution as early determinants of airway disease were based on the assumption that the placenta was shielding the fetus from both, keeping the growing lungs “clean” until birth. However, in recent years, it has become increasingly evident that – in addition to chemicals – viruses and other small particles coming from the environment can cross the placental barrier and impact the fetus. Even an imbalanced maternal diet during pregnancy can have dire consequences for fetal development, both directly and by increasing the toxicity of other agents.

In particular, our studies confute the “sterile womb dogma” and provide compelling evidence that RSV can be transmitted via the bloodstream from the infected airways of a pregnant mother to the lungs of her unborn child. We have preliminary evidence that also inert metallic particles present in many commercial products might do the same and add to the fetal damage. 

MedicalResearch.com: What recommendations do you have for future research as a result of this work? 

Response: I think it is imperative to continue and expand the research into the complex interactions within the mother-fetus dyad, and in particular focus on the consequences of environmental exposures of pregnant mothers on fetal development. We have known for many years that several infections – such as toxoplasmosis, rubella, CMV, herpes – can be transmitted to the fetus and cause severe structural deformities manifesting at birth. More recently, media have focused on previously unknown threats like the Zika virus, again due to the emergence of obvious structural defect like microcephaly in the infected newborns. However, our research suggests that also viruses that do not generate macroscopic congenital malformations can produce more subtle deviations in the developmental trajectory of apparently normal offspring, resulting in predisposition to chronic diseases like asthma, diabetes, even cancer.

This hypothesis may also explain the epidemic increase of several chronic disorders in the population.

MedicalResearch.com: Is there anything else you would like to add?

Response: Healthcare costs in the U.S. already account for ~18% of our GDP, and continue to grow steadily year over year. Yet our expensive healthcare system is failing to achieve its goals because of its focus on treatment rather than prevention. To reverse this ominous trend, the bulk of available resources should be dedicated to the protection of pregnant women, rather than to the therapy of irreversible chronic diseases and end-of-life palliation. Indeed, chronic diseases like obesity, diabetes, asthma, and even some forms of cancer have become epidemic and their management in adulthood is escalating the costs of healthcare to proportions unsustainable for any world economy.

If we want to prevail in the war against chronic diseases that so far have eluded any therapeutic strategy, it is essential to recognize that the months spent in our mothers’ womb may be the most consequential of our lives, and identify the intrauterine and early life events shaping organ development to prevent or redirect dysfunctional phenotypes before they result in actual disease. Securing a balanced and healthy diet, clean air to breathe, and viral prophylaxis to all pregnant women and their offspring during early childhood should be the first and most important step in this direction.

Citation:

Respiratory syncytial virus exhibits differential tropism for distinct human placental cell types with Hofbauer cells acting as a permissive reservoir for infection

Vladimir Bokun,, John J. Moore, Robert Moore, Carrie C. Smallcombe, Terri J. Harford, Fariba Rezaee,, Frank Esper ,Giovanni Piedimonte

Published: December 2, 2019

https://doi.org/10.1371/journal.pone.0225767

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Last Updated on December 4, 2019 by Marie Benz MD FAAD