They discover how obesity is a risk factor for severe COVID

The obesity is one of the factors influencing the COVID-19 can develop seriously. A group of Spanish scientists has discovered the mechanisms involved in this relationship and proposes a biomarker, through a blood test, that can detect this risk.

The research, led by the Spanish Obesity and Nutrition Network Biomedical Research Center (Ciberobn), focuses on the visceral adipose tissue of obese patients and the ACE2 gene, which, in addition to functioning as a gateway for the SARS virus -CoV-2, is involved in inflammatory processes in the body.

An overweight person “usually” has the ACE2 gene less expressed in adipose tissue and, when infected, those levels decrease even more, which can make them more susceptible to the cytokine storm with which the body responds in occasions before the coronavirus and that aggravates the disease, explains Ana Belén Crujeiras, Ciberobn researcher and leader of the investigation.

The team focused on the so-called methylation marks, a fundamental epigenetic mechanism in the regulation of gene expression and how they work.

This mechanism consists of chemical marks that are added to DNA in response to factors such as the environment, diet, physical activity, exposure to toxins or psychological state.

If DNA has been described as the “book of life, made up of a large succession of combined letters, Crujeiras explains that the methylation marks would be the spelling.

A comma in the right place makes the body work correctly, but in the wrong place it can change the meaning of the sentence and lead to the development of diseases.

The interesting thing about these methylation marks, he says, is that, unlike genetic mutations, they can be reversed, for example, by going from a bad diet to a healthy one.

The team studied ACE2 in the adipose tissue of obese patients and others with normal weight, to verify that in the former it had “high levels of these methylation marks”.

Patients who were treated for weight loss on a very low-calorie ketogenic diet or a balanced low-calorie diet later had levels of methylation markers similar to people of normal weight.

ACE2 is involved in inflammatory processes in the body and, when highly activated, triggers anti-inflammatory mechanisms that exert a protective action in the body.

However, when a gene has high methylation marks, as occurs with ACE2 in overweight people, its expression generally decreases, Crujeiras details.

A person with obesity is in a chronic low-grade inflammatory state and, if the action of the ACE2 gene is also reduced, it will cause the inflammation to be greater after infection by COVID-19.

Crujeiras points out that this possibility “correlates perfectly with the results observed in visceral adipose tissue” and its implication in the development of other obesity-related diseases such as cardiovascular disease, diabetes or cancer.

“The expert indicates that methylation marks could be a biomarker to determine the risk of a person with obesity to suffer from severe COVID-19, since the same pattern observed in adipose tissue has been seen in leukocytes and can be detected with a sample. minimally invasive blood