“Lactoferrin, a natural protein found in bovine milk, in combination with a specific probiotic, Lactobacillus paracasei DG, could contribute to the prevention of Covid-19 and relieve symptoms associated with the infection. The data emerging from an in vitro study on lactoferrin are very interesting “. This was stated by the virologist of the University of Milan to time.news Salute, Fabrizio Pregliasco, Health Director at the Galeazzi Orthopedic Institute in Milan, one of the authors of the research published last August in the journal Gut microbes.
The antiviral immune effects and anti Sars-CoV-2 activity of three Lacticaseibacillus probiotic strains (L. paracasei DG, L. rhamnosus GG, L. paracasei LPC-S01), alone or in combination with lactoferrin in vitro, using an intestinal epithelial cell line Caco-2, which expresses the Ace2 receptor. The intestine, indeed, represents another viral target organ that supports SarS-CoV-2 replication.
SarS-CoV-2 infection spreads mainly through droplets and respiratory secretions, however “the intestinal tract – explains Pregliasco – it could be another potential channel of infection, and in about 17% of cases, respiratory symptoms are associated with gastrointestinal disorders. These data suggest that the gastrointestinal tract could be a location for viral activity and replication ”.
Probiotics act “both on the innate immune system – reiterates Pregliasco – both on the acquired one and have the potential to reduce the severity of infections in the gastrointestinal and upper respiratory tract. They exhibit their antiviral activity through direct interaction with the virus, the production of antiviral metabolites, the stimulation of the type I interferon response and the production of antibodies against the virus. The potential of probiotics in reducing the risk and severity of viral respiratory tract infections is also supported by clinical and experimental studies of influenza, rhinovirus, and respiratory syncytial virus. So far these effects had not been tested on Covid-19, but some probiotics had demonstrated antiviral activity against other coronaviruses. Lactoferrin, a naturally derived substance, has shown antiviral, immunomodulatory and anti-inflammatory effects, so our hypothesis, confirmed by the study, concerned the possible synergy between probiotic and lactoferrin“.
The results confirm that the three probiotics stimulate antiviral activity at different levels, but L. paracasei DG is the most effective and promising in terms of antiviral immunomodulatory activity and able to induce the expression of genes involved in the antiviral response, such as IFNA1 and IFNB1 (antiviral cytokines), TLR7 and IFIH1 (involved in virus recognition), IRF7 and MAVS (participate in the signaling pathways of the antiviral response). “Our work demonstrates that the Lacticaseibacillus paracasei DG strain is a promising candidate with potential for prophylaxis against infection.”Underlines Pregliasco, who adds:“ Not only is the antiviral activity of L. paracasei DG confirmed, but also its ability to suppress Sars-CoV-2 replication by 50% in vitro. Lactic acid bacteria, such as L. paracasei DG, produce a wide variety of antimicrobial compounds, such as hydrogen peroxide, lactic acid and bactericidal substances, capable of reducing viral load. ”
These results “which were not observed with the other two strains tested, demonstrate how important it is to choose the right probiotic – continues the expert – The results are decidedly positive, so the expectation of confirmation in a subsequent in vivo experiment is growing. . “The beneficial and antiviral effects of probiotics and lactoferrin in humans lead us to think that their association may confirm the data of our work also in a future in vivo study.“. Regarding the possible future clinical developments of the study, Pregliasco has no doubts: “On Sars-CoV-2 this research is important but it is clear that we do not want to be the therapeutic alternative in the face of a need for studies, clinical trials and all insights into the case. As I had already seen for other probiotics, however, their use as adjuvants in terms of prevention and strengthening of the immune defenses is confirmed “.