Potential of bifidobacteria and selenium flagged in COVID-19 fight

15 Sep 2020 --- Bifidobacteria and selenium have both come under the spotlight in the fight against COVID-19.

According to a Russia-based geneticist, the FN3 surface protein found on B. longum blocks or binds some types of cytokines, thus stopping excessive or uncontrollable inflammation. When there are too many cytokines, a cytokine storm occurs. This dangerous and sometimes deadly reaction can be observed in severe cases of COVID-19. 

“Selective binding of TNF-α, one of the key factors of inflammation, with a fragment of the FN3 protein of B. longum opens a prospect for developing new medicinal drugs that would slow down the cytokine reaction,” says Valery Danilenko, biology professor from RUDN University, Moscow. 

He adds that it has already been agreed that a preclinical trial of a new FN3-based anti-inflammatory medication should be conducted as soon as possible.

Delving into the science
The researchers discovered that FN3 helps cells attach to different surfaces, including intestinal walls covered in mucus. Moreover, it has two protein-carbohydrate moieties (fibronectin domains) that are similar to human cytokine receptors. The experiment showed that FN3 is able to bind TNF-α, one of the main cytokine storm factors.

Of four cytokines that belonged to different classes, only the tumor necrosis factor TNF-α showed effective binding. 

The team theorized that the bifidobacterial are capable of regulating immune responses. This was backed by the finding that bifidobacterial surface proteins were able to recognize specific classes of cytokines.

According to the researchers, studies like this are especially important for understanding the processes of immune development in newborn babies, as their intestinal microbiome almost entirely consists of bifidobacteria. 

Biologists also believe that the tumor necrosis factor-specific fragment of FN3 can reduce the levels of cytokine storm in COVID-19 patients.

This is not the first time that probiotics have formed part of the COVID-19 conversation. In May, ADM Biopolis launched a clinical trial into the effects of administering a food supplement containing three of ADM’s live probiotic strains on COVID-19 patients. Lallemand and Biosearch Life have also made moves in this space.Bifidobacteria may be able to be used to make an anti-inflammatory medication when treating COVID-19 and other diseases (Credit: RUDN University). 

Looking to selenium
Meanwhile, a review published in Frontiers in Nutrition lays out a three-pronged approach for using selenium to help combat COVID-19 fatalities. 

The researchers detail that selenium deficiency promotes mutations, replication and virulence of RNA viruses, including the one responsible for COVID-19. Additionally, low selenium status has been associated with severe COVID-19, especially in the elderly. 

According to the scientists, the element may be beneficial via restoration of host antioxidant capacity, reduction of apoptosis and endothelial cell damages as well as platelet aggregation.

“Selenium has been overlooked but may have a significant place in COVID-19 spectrum management, particularly in vulnerable elderly, and might represent a game-changer in the global response to COVID-19,” they write. 

Prevention, documentation and treatment
The first step in implementing the selenium plan revolves around prevention. The researchers recommend supplementing populations at risk of developing severe COVID-19 – including the elderly with co-morbidities and the obese – before they become infected.

Specifically, this would involve 200 mcg selenium supplementation daily for three weeks followed by a maintenance dose of less than 200 mcg throughout the active circulation of SARS-COV-2. 

The researchers say this seems “safe and sound,” considering the high mortality risk related to COVID-19 in these vulnerable subgroups.

However, they acknowledge that long-term supplementation needs special attention and it might be recommended to monitor glycemia after a few weeks.

The next step is the documentation of serum selenium status whenever possible in hospitalized COVID-19 patients.

Finally, symptomatic patients should be treated with selenium. The researchers recommend that outpatients at all ages have the systematic addition of selenium. Meanwhile, sodium selenite is recommended upon hospital admission as soon possible, before the deadly cytokine storm arises. 

“Pending the development of an effective vaccine, while faced with the deadly COVID-19 pandemic and especially the unprecedented pressure it exerts on the health care system, the potential use and effectiveness (or not) of sodium selenite must be urgently tested and documented in outpatient as well as inpatient settings,” the researchers write. 

They conclude that as some countries enter the post-confinement era, implementing preventive selenium supplementation, especially in the elderly, represents a sound, safe and feasible strategy. “Selenium with its pleiotropic effects in the COVID-19 disease spectrum may become an important research topic in human health.”

In May, an analysis found a correlation between low selenium levels and COVID-19 death rates in China. 

By Katherine Durrell