Alterations in the composition of the gut microbiota caused by Covid-19 can reveal the risk of serious disease
For some time, several studies on sars-CoV-2 virus infection have focused attention on the role of bacteria, viruses and other invisible inhabitants of the human intestine, which make up the so-called "microbiota". Now an Italian research demonstrates how Sars-Cov-2 infection causes alterations of the flora in, published in the prestigious journal Plos One, reveals how the study of this population with new generation genomic sequencing systems can provide new tools for diagnosis and for Covid-19 therapy, and to better define who runs the greatest risk from infection.
The study was conducted by scholars from the National Institute of Infectious Diseases "Lazzaro Spallanzani" (INMI) in Rome and by the IRCCS "Casa Sollievo della Sofferenza" in San Giovanni Rotondo.
From the respiratory tract to the intestine
The Sars-Cov-2 virus has now been understood, it does not limit its effects only to the respiratory system, although interstitial pneumonia remains one of the most serious symptoms to be faced in serious forms. In fact, it has been seen that it can also attack other organs, such as the intestine: the Ace-2 receptor, which is the gateway through which the virus enters human cells, is also abundantly present in the cells of the gastro-intestinal tract. .
Furthermore, an important proportion of Covid-19 patients show gastrointestinal symptoms, and various studies in the past have shown that respiratory infections, and among them Covid-19, are associated with alterations in the composition of the intestinal microbiota, that complex "community" composed mainly of bacteria, but also of yeasts, parasites and viruses, which we commonly call "intestinal flora" and which plays an essential role in maintaining the balance (the so-called "eubiosis") of the organism.
Recent research has highlighted the existence of a "lung-intestine axis", in which the intestinal microbiota, when the intestinal immune cells have identified foreign pathogens, releases microbial and immuno-modulatory products that help regulate lung immunity, and vice versa . Scientists from Spallanzini and Casa Sollievo della Sofferenza have hypothesized that Sars-Cov-2 pneumonia can affect the intestinal microbiota, and that diagnostic markers can be extracted from these alterations that could be of great help in the stratification of patients and related patients. severe disease risk profiles.
For the research, rectal swabs of 23 patients admitted to the INMI were collected between April and May 2020, divided into three groups: nine positive for Sars-Cov-2 hospitalized in ordinary hospitalization, six positive for Sars-Cov- 2 hospitalized in intensive care, and eight patients hospitalized in ordinary hospitalization or intensive care but negative for Sars-Cov-2, used as control group. The samples of these patients were then subjected to genomic sequencing of 16S ribosomal RNA, a technique that allows for the identification of the various microorganisms present in the microbiota in a much faster and more efficient way than traditional microbiological techniques. The analysis revealed significant differences in the composition of the microbiota between the three groups of patients. Compared to the control group and patients in ordinary hospitalization, patients with more serious forms, for example, showed a decrease in the Chao1 index, which measures microbial richness.
From the laboratory to therapies
"Our research is only the first step in a new and promising area of research, which will be deepened with larger groups of patients and also including patients with paucisymptomatic or asymptomatic patients – explain Antonio Mazzarelli and Maria Letizia Giancola of INMI. What is clear, however, is that the intestinal flora of Covid-19 patients presents significant differences: both compared to non-Covid-19 patients, and in relation to the different degree of severity of the disease. This evidence is of great importance, which opens the way to subsequent promising diagnostic and clinical applications ".
"These data may open new perspectives also in the therapeutic field in the near future – adds Valerio Pazienza, biologist of the Gastroenterology Research Laboratory of IRCCS Casa Sollievo della Soflievo. It is possible to assume an adjuvant therapeutic option to the current treatments available today, where the integration of specific mixtures of probiotics, appropriately selected to selectively compete with the harmful microorganisms increased in Covid-19 patients, can both mitigate the loss of richness of the intestinal microbiota and mitigate the course of the disease, possibly avoiding the risk of transfer to the intensive care unit for Sars-CoV-2 positive patients ".
Tag: Coronavirus Infectious diseases