A human gut microbiota has been discovered that it has the potential to alleviate the effects of the respiratory syncytial virus (RSV), which is responsible for lower respiratory tract infections, particularly bronchiolitis, in children aged 2 and less. The virus has claimed the lives of around 100,000 people around the globe.
The research was carried out under the supervision of four other FAPESP projects (18/15313-8,20/04583-4,17/06577-9and20/13689-0). In an articlepublishedineBioMedicine, the latest findings are revealed.
According to the author of the article, a short-chain fatty acid acetate from the gut microbiota protected mice against RSV and mitigated the severity of the disease in those already infected. We also determined that antioxidants enhance human cells and in animals; we also found that it would inhibit certain signs and symptoms from the virus in humans; also found that a reduction in the disease would be required by the author. In particular, Dr. Aurelio Ramirez Vinolo, a professor at the
While a premature baby is infected, the monoclonal antibody palivizumab is recommended to prevent lung disease, but this prophylactic treatment is cost effective.
According to the researchers, a low-cost natural product from gut microbiota might be able to treat severe RSV infection directly in the respiratory tract. Krist H. Antunes, a postdoc in pediatrics and immunology at the Pontifical Catholic University of Rio Grande do Sul (PUC-RS) in Porto Alegre, Brazil, is the first author of the article.
During the COVID-19 epidemic, the number of other viral respiratory infections has temporarily decreased, but RSV bronchiolitis cases have recently recovered. Off-season outbreaks of such infections pose a threat to vulnerable babies, strengthening the importance of affordable prevention.
Laboratory tests
Different approaches were used in mice to alter gut microbiota, such as administering antibiotics and increasing the amount of fiber in their diet, for example. Resistance to infection increased when the microbiota increased, according to Vinolo. Laboratory investigations in which cells were treated with this acetate also provided significant results.
The results of the experiments identified a laboratory-grown viral strain that differed from the one that circulates among humans. For the most part, researchers used oral oral tablets to extract the virus from two individuals who were previously treated with acetate.
Acetate activated the production of antiviral molecules, among which RIG-I sounded particularly effective against RSV. In cells without RIG-I, the acetate failed to prevent the progression of infections.
The children were inoculated into mice in the next phase, reducing viral load by 93% and reducing airway inflammation.
Gut microbiota in infants with bronchiolitis
Thirty infants aged less than 12 months were recruited in collaboration with Ana Paula Duarte de Souza and Renato Stein, both of whom are professors at PUC-RS. Stool samples were collected from 17 of the infants. We evaluated the composition of their gut microbiota and determined the levels of short-chain fatty acids, according to Vinolo.
Combining this data with clinical evidence on the children''s bronchiolitis, high levels of acetate were associated with less severe respiratory disease, particularly higher oxygen saturation and decreased days with fever.
This type of study hints to a correlation, but does not indicate its validity as a result of Vinolo''s findings. Nevertheless, it gives an additional hint for continuing to examine gut acetate.
The researchers collected cells from the same airways and treated them with acetate in the laboratory to confirm their findings. As previously, viral load decreased and the activity of antiviral molecules increased.
The COVID-19 epidemic began when the team performed similar experiments using the compound against SARS-CoV-2. Positive effects were not observed in this case. This coronavirus is different from RSV. The pathways activated by the acetate may not imply its action, according to Vinolo.
Future implications
Vinolo believes that sufficient evidence has been obtained for the group to begin clinical trials designed to verify the safety and benefits of using acetate to prevent or control bronchiolitis. However, the pandemic has been difficult. We expect to complete the first trial in 2022, possibly with intranasal therapy.
Despite the fact that other short-chain fatty acids produced by gut microbiota have similar effects, they do not reach the bloodstream in large quantities, according to Vinolo. Acetate contains high levels in various parts of the organism, such as the lungs.
The body''s role is emphasized in the organism''s role, particularly in the immune system. For Vinolo, this is a good opportunity for everyone to aim for a balanced diet with plenty of soluble fiber, including cereals such as oats, linseed, and chia, legumes such as lentils and dry beans, and fruit such as apples and bananas.
We do not know whether gut microbiota acetate production may be sufficient to protect human infants, but this is the possibility in laboratory animals, according to Vinolo.