Study found that the placenta can block the transmission of SARS-CoV-2 to the fetus

A survey published in the journal The Journal of Clinical Investigation aims to demonstrate that the technology applied for the molecular analysis of tumors has been used to perform a complete clinical, morphological and molecular analysis of the placentas of pregnant women with and without SARS-CoV-2 infection, who gave birth during the first wave of the pandemic in Italy.

“Thanks to this work, we were able to verify that, although the virus could infect the placenta, in no case was there vertical transmission from mother to newborn, which suggests that the placenta may be a barrier. maternal-neonatal effective against the virus, even in the presence of severe infectionSays Dr Paolo Nuciforo, head of the molecular oncology group at the Vall d’Hebron Oncology Institute (VHIO), and co-author of the work with Dr Joan Seoane.

The director of Oncolgy at the Alexander Fleming Institute, Dr. Matías Chacón (MN 86697), underlines that “it is essential to understand from this work in which it follows that the placenta plays an important role in blocking the transmission of the virus to the fetus. And the presence of the virus in the placenta depending on the amount of viral load that generated a major or minor inflammatory reaction. If the inflammatory reaction is very severe, the placenta may be damaged but there is no infection in the fetus ”.

“This is a very important study which shows the great capacity of the organism to generate an inflammatory reaction, whether it is innate with very primitive cells, or an adaptive immune response with more complex cells, which are B lymphocytes. , which generate antibodies. These are therefore ways of reacting not only against a virus but also against cancer. This scenario that presents itself is very similar to what we see in oncology, where whenever we rely more on immunological knowledge and on our body’s ability to generate an antigen-antibody reaction against the presence of a tumor cell “said the specialist.

Another of the trial authors, Dr Joan Seoane, adds that “for the first time we have determined the viral load in placental tissues using the combination of PCR and in situ hybridization techniques and it has been shown that, although occasionally, SARS -CoV-2 can massively infect placental cells and cause their death ”.

In addition, he adds: “The virus seeks to escape the control of the immune system and for that it develops different strategies. This is something that it has in common with tumor cells. We wanted to offer our experience in this regard, bringing everything we have learned in the context of cancer. Thus, we observed that the strategies used by tumor cells to evade the immune system are similar to those used by the virus “.

On the other hand, indicate how what is discovered about the SARS-CoV-2 virus itself can be used to develop new cancer treatments, and vice versa, apply what is known about cancer to research treatments for COVID-19.

“From this work we can deduce that an inflammatory reaction can contain a virus and we have known for many years that a good inflammatory response can also stop or slow down tumor cells”, explains Chacón. “These assumptions in cancer, at present, most pathologies are treated not only by chemotherapy or hormone therapy, but also immunotherapy has invaded almost all tumor models with great success. And what does immunotherapy do? Basically, it triggers inflammatory responses or decreases the ability of this tumor cell to evade the immune system. Then, the work allows us to continue to understand or understand the mechanisms of escape, whether it is a virus or a tumor cell of our immune system “.

To carry out the study at the Vall d’Hebron Institute of Oncology, 37 pregnant women were analyzed, 21 of whom had confirmed an infection with SARS-CoV-2 during a PCR test. All of the women gave birth to live asymptomatic newborns, except in two cases. One patient who tested negative underwent induction of labor for a therapeutic miscarriage due to a chromosomal abnormality, and another of the newborns, in this case a positive patient with SARS-CoV-2, had showed perinatal asphyxia requiring mechanical ventilation and supplemental oxygen for the first three days of life, followed by epilepsy episodes and neurological symptoms which gradually resolved after drug treatment.

However, for the head of oncology at Fleming, the study shows extrapolations, because the work does not homologate cancer and viral disease as the same entity, but rather allows us to have hypotheses. “In the case of the virus, we have seen that the higher the viral load, the greater the inflammation and possibly the greater the reaction against the coronavirus virus.. In the case of cancer, the patients’ immune system is not so intact, it has such a great capacity to react against the presence of the tumor. So, many times against the tumor, the immune system itself can no longer inflame the body to get more cells capable of destroying tumor cells.. This is a big step forward, a milestone in oncology. It has been in effect for over 10 years. Just like in 1965, Milstein developed monoclonal antibodies, which are one of the fundamental tools for blocking the stages between what is the aggressor, in this case the virus or cancer, and the host that we and our immune system are ‘.

The study carried out was also able to verify that, in order for this damage to occur in the placenta with any implication in the outcome of pregnancy, it is necessary that a high viral load reach this organ, although it is not directly related to any known clinical or pathological parameter in pregnant women. “Right now, we don’t know how to correctly identify these patients, in order to offer them a different treatment that will prevent the placenta from being affected. There are different alternatives, such as the development of possible markers in the blood of patients, but this is still an unexplored path on which further research is needed ”, comments Dr Paolo Nuciforo.

But what is the similarity to cancer? “The mechanism of tumor growth is that of viral expansion. The virus or cancer is always trying to develop strategies, which are cellular, complex, which require the immune system, which is not only the presence of white blood cells, but also the coordination of the formation of lymphocytes, the release of substances appropriate, the approach of the offending cell, which in this case may be a tumor or a viral cell, and be able to eradicate it. You can also leave antibodies and leave memory so that this does not happen again. It is really a coordination job. It is currently called a very large intersection between what is the immune system and tumor cells or the immune system and viral load. This is in vogue because of the extensive development of what is essentially the microbiome, which is the collection of bacteria and microbes that inhabit our bodies, ”explains Chacón.

It would also allow us to have a better immune response or less immune response. In cancer it is very developed and five or six years ago it was not mentioned. These are really strategies where viral agents teach us not only to have better immune responses, but also to understand escape mechanisms. And this is where humans can also intercede and invent monoclonal antibodies that block certain steps and make their own immune response much more effective than we would naturally have.

But why study a virus in a cancer research center? Research into infectious diseases and cancer can go hand in hand. Infectious diseases are of great concern to oncologists. This is due to the fact Cancer patients who receive chemotherapy or immunotherapy and are particularly vulnerable to infections, such as SARS-CoV-2, because their immune systems are weakened. Understanding the intersection between the two diseases represents an extraordinary opportunity to prevent and treat cancer.

I KEEP READING