Study unveils reasons some patients to develop more severe COVID-19 symptoms

Findings of research conducted at PUCRS were published in Frontiers of Immunology

08/02/2021 - 14h25

Photo: Unplash

Although there are risk groups for Covid-19, some people who are not in these groups may need hospitalization when their symptoms get worse, whereas other patients in the risk group may present only milder symptoms. As researchers from PUCRS’ Cell and Tissue Biology Laboratory, in partnership with researchers from UFCSPA and UNIVATES, engaged in studying this issue further, they have found a possible explanation in the levels of angiotensin II in the blood. Angiotensin (both I and II) is a polypeptide, that is, a set of amino acids, that, among other functions, regulates blood pressure, as explained by Léder Leal Xavier, professor of Physiology of PUCRS’ School of Health and Life Sciences and one of the leaders of the study.  

The way Xavier sees it, the Covid-19 virus gets into the human cells through an enzyme that is found in the membrane of these cells, known as angiotensin-converting enzyme 2 (ECA2), which is mostly found in the lungs. It is, therefore, the “bridge” for the virus into the body. Angiotensin II, in turn, removes ECA2 from the cell membrane. Without this “gateway”, the amount of virus that can effectively get into the body can be much smaller. The research group hypothesizes that patients who manage to increase levels of angiotensin II during Covid-19 infection have a lower viral load and can activate the immune system appropriately, thus having a better prognosis. However, some people are unable to produce an increased amount of angiotensin II levels, and consequently, their viral load tends to be high. Because they do not activate the immune system properly at the onset of the disease, they may experience more severe symptoms.  

The study, which is being spearheaded by PhD student Paula Neves, enrolled in the Graduate Program in Cellular and Molecular Biology of PUCRS (PPGBCM), can help explain why this happens and advance possible treatments for COVID-19, as well as other infections for other viruses that may eventually be found, using ECA2 as a gateway into the human body. “It is important to know the basic biology of diseases in order to take further action”, Léder adds.  

PPGBCM’s postdoctoral research fellowDr. Andrea Wieck Ricachenevsky, on the other hand, commends the importance of congregating scientists from different institutions: “These researchers have different backgrounds and specialize in different areas. In addition, because they offer different points of view on the topics in question, this can advance multidisciplinarity, which is very important in a study”.  

At last, according to the researchers, the study draws insights from physiological and biochemical theories about the human body’s responses to Covid-19 and other viral infections. The way they see it, it can serve as a basis for future studies in search of treatments that mitigate the effects of these diseases. However, they stress that basic measures such as social distancing, use of masks, vaccination and a visit to the doctor on any suspicion of Covid-19 are priorities. Up until now, the study is not intended to make any adjustments to the clinical treatment patients receive, since, for the time being, there is no “universal” medication for Covid-19, but different treatments for each symptom, to be prescribed by a medical doctor.  

You can get access to the full article, published in the journal Frontiers of Immunology here