Altered gut microbial metabolites could mediate the effects of risk factors in Covid-19

Summary of a published review by the Medlab Research Department

DATE: Tuesday 28th September 2021
Author: Medlab,

Categories > Article

With 219 million cases worldwide and 4.55 million deaths the coronavirus has shaken the world we know, perpetually changing our lives forever. With every country facing the ongoing effects of the pandemic, it is assured that COVID-19 is here to stay.

Coronavirus disease 2019 (Covid-19), caused by severe acute respiratory syndrome coronavirus 2 infection, has caused a pandemic. Whilst most Covid-19 patients present with mild symptoms or are asymptomatic, a proportion will develop severe disease, which could be fatal. The effects of the pandemic have had a detrimental effect on not only our public health systems but our economy, our futures, and our lives.

The studies of gut dysbiosis in Covid-19 could provide preventive and therapeutic opportunities. Over the last 5 years, Medlab has carried out extensive research and initiated clinical trials relating to the gut microbiome, the effects of probiotics for chronic conditions and developed technologies (NanoCelle®) to improve patients’ quality of life. Naturally, research into the relationship between our gut microbiota and Covid-19 was of grave interest to us.

In a published review titled ‘Altered gut microbial metabolites could mediate the effects of risk factors in Covid-19’, Jiezhong Chen, Sean Hall (Medlab’s CEO) and Luis Vitetta (Medlab’s Director of Medical Research) explore how the roles of the gut microbiota and COVID-19 pathogenesis could have important implications in the prevention and treatment of the disease.

Clinically, Covid-19 patients manifest fever with dry cough, fatigue and dyspnoea, and in severe cases develop into acute respiratory distress syndrome (ARDS), sepsis and multi‐organ failure. These severe patients are characterized by hyper inflammation with highly increased pro-inflammatory cytokines which are accompanied by decreased lymphocyte counts. Clinical evidence supports that gut microbiota dysregulation is common in Covid-19 and plays a key role in the pathogenesis of Covid-19.

In their research, Jiezhong Chen, Sean Hall, and Luis Vitetta summarize the roles of intestinal dysbiosis in Covid-19 pathogenesis and hypothesise that the associated mechanisms are being mediated by gut bacterial metabolites. Based on this premise, they propose possible clinical implications. Various risk factors associated with gut dysbiosis could be causal for severe Covid-19, and these include ageing, concomitant chronic disease, SARS-CoV-2 infection of enterocytes, use of antibiotics, dietary factors, and psychological distress. Understanding how SARSCoV-2 causes severe Covid-19 is critical to reducing morbidity.

Recent studies have reported that the gut microbiota is dysregulated in Covid-19.15-17 By comparing gut microbiota in 30 hospitalized Covid-19 patients and 30 healthy participants, it was reported that intestinal dysbiosis was associated with the Covid-19 patients. Compared to healthy patients, Covid-19 positive patients had increased opportunistic pathogens and decreased beneficial commensal bacteria. Dysregulation of gut microbiota (dysbiosis) is associated with risk factors and severe Covid-19 due to decreased commensal microbial metabolites, which cause reduced anti-inflammatory mechanisms and chronic low-grade inflammation. The preconditioned immune dysregulation enables SARS-CoV-2 infection to progress to an uncontrolled hyperinflammatory response.

Understanding the important roles of the gut microbiota in the pathogenesis of Covid-19 could have important implications in the prevention and treatment of the disease. Healthy gut microbiota can maintain an immune system that is in equilibrium ready to neutralize Covid-19 viral assaults. Hence, a pre-existing balanced pro- and anti-inflammatory gut of microbial metabolites could potentially avoid hyper inflammation after Covid-19 and thus prevent severe Covid-19. Various approaches which could improve the gut microbiota could be used beneficially, particularly in vulnerable populations. The aged or those with underlying chronic diseases may greatly benefit from a gut microbiota that may be improved with the administration of probiotics, prebiotics and synbiotics.

Gut microbiota and bacterial metabolites could also be involved in the prevention and treatment efficacy of other agents used in the treatment of Covid-19, such as vitamin D. Low levels of vitamin D are now known to be associated with the severity of Covid-19; low concentrations of vitamin D and its metabolite 25-hydroxy vitamin D are inversely correlated with the severity of Covid-19.139,140

To summarise, a pre-existing gut microbiota that is diverse and abundant could be beneficial for the prevention of severe Covid-19, and supplementation with commensal microbial metabolites may facilitate and augment the treatment of severe Covid-19. The studies of gut dysbiosis in Covid-19 could provide preventive and therapeutic opportunities. But, this is only the beginning, with researchers focusing their efforts on important means of controlling the virus, we look forward to furthering our research into NanoCelle®  small molecules and biologics to accelerate the development of potential therapies where it is needed most.

A full list of references is available in the published review.

Read full published review

About the author


Medlab in-house Editor.