# Protective potential of mesenchymal stem cells against COVID-19 during pregnancy

## TL;DR

This paper explores how mesenchymal stem cells from the fetus may protect pregnant women from severe COVID-19 symptoms.

## Contribution

The paper proposes a novel hypothesis that fetal mesenchymal stem cells may naturally protect pregnant women from severe SARS-CoV-2 infection.

## Key findings

- Pregnant women are less likely to develop severe forms of COVID-19 compared to non-pregnant individuals.
- Mesenchymal stem cells (MSCs) from fetal tissues may confer protective effects against SARS-CoV-2-induced inflammation.
- MSCs are being tested in over 100 clinical trials for treating severe cases of COVID-19.

## Abstract

SARS-CoV-2 causes COVID-19. COVID-19 has led to severe clinical illnesses and an unprecedented death toll. The virus induces immune inflammatory responses specifically cytokine storm in lungs. Several published reports indicated that pregnant females are less likely to develop severe symptoms compared with non-pregnant. Putative protective role of maternal blood circulating fetal mesenchymal stem cells (MSCs) has emerged and have been put forward as an explanation to alleviated symptoms. MSCs with immune-modulatory, anti-inflammatory and anti-viral roles, hold great potential for the treatment of COVID-19. MSCs could be an alternative to treat infections resulting from the SARS-CoV-2 and potential future outbreaks. This review focuses on the MSCs putative protective roles against COVID-19 in pregnant females.

The COVID-19 outbreak is still posing a global health concern. Despite the herd immunity provided by vaccination programs, no efficient treatments are yet available especially against the severe forms of the disease. According to published reports, pregnant females are less likely to develop the severe form of the disease due to the protective effect of specialized cells named mesenchymal stem cells (MSCs). These cells are present in the placenta and amniotic fluid. They can migrate from these tissues to the mother's blood stream and are believed to confer protection to the pregnant females against severe form of COVID-19. Further investigations are on the way to uncover the potential role of MSC as an alternative therapy for COVID-19 and other diseases.

The virus SARS-CoV-2 results in COVID-19 infection. Several reports indicated that pregnant females are less likely to develop severe symptoms. Circulating fetal Mesenchymal stem cells in pregnant females might protect them.

SARS-CoV-2 result in highly contagious condition, the COVID-19. Symptoms can vary from asymptomatic, mild to severe respiratory distress. Antiviral, antimalarial, and anti-inflammatory medications were tested in COVID-19 treatment studies, but none of them were found to be effective. The available therapies and vaccinations are insufficient to fully guard against COVID-19 infection and its associated complications.

Since the COVID-19 outbreak, stem cells, in particular mesenchymal cells (MSCs), have received attention as an alternative therapy and are now emerging as a promising therapeutic option against COVID-19. Currently, MSCs are being used in more than 100 clinical trials to treat COVID-19 (source: Clinicaltrials.gov). According to several reports, patients in the majority of clinical trials using MSCs for the treatment of COVID-19 recovered well, with less lung damage and better survival. MSCs are a feasible treatment option for COVID-19 patients, particularly for those who are in a critical condition.

Several studies imply that pregnant women are less likely to get the severe form of COVID-19, although preclinical and clinical settings are still needed to confirm this. The number of critical cases of COVID-19 infection was extremely low in pregnant women. SARS-CoV-2 mother-to-fetus transmission has not been documented in the majority of COVID-19-pregnancy cases.

The presence of fetal MSCs in the mother's blood raises the possibility that MSCs from fetal tissues (placenta, amniotic fluid, cord blood) may shield the mothers from the potentially harmful effects of COVID-19 while they are pregnant. Maternal blood circulating fetal MSCs might be naturally safeguarding pregnant women.

MSCs, due to their anti-inflammatory, immunomodulatory, and antiviral activities, constitute a promising therapeutic target against SARS-CoV-2 induced inflammation. Lactoferrin may also defend against viral infection in females by lowering ACE2 together with the low expression of TMPRSS2 which are necessary for SARS-CoV-2 entry in the cells. The successful outcomes of MSCs clinical trials in COVID-19 patients, especially those in critical conditions, could be a treatment option for all including pregnant females, and those with underlying conditions. Clinical trials on the application of the fetal MSCs to pregnant females with COVID-19 would confirm the hypothesis.