Research led by investigators from the Center for Gut Microbiota Research, the Chinese University of Hong Kong, pursued a recent two-hospital cohort study first recognizing that COVID-19 worsens due to a berserk immune system, and that these patients infected with SARS-CoV-2 exhibit a markedly different gut microbiome. Published recently in the journal Gut in January 2021, it turns out according to observations based on the study, involving samples from 100 patients confirmed with COVID-19 that there is in fact an association between gut microbiota make up, cytokines and inflammatory markers. This suggests that the gut microbiome is associated with COVID-19 intensity and severity, perhaps even modulating host immune responses. Moreover, the Hong Kong-based researchers posit that the effects associated with so-called Long Covid, that is the long-term symptoms that many who recover from COVID-19 still experience, may in fact be associated with gut microbiota dysbiosis—that is the microbial imbalance or maladaptation from an impaired microbiota. Could at least part of the key to better understanding cause and cure to COVID-19 be associated with how gut microorganisms are associated with the novel coronavirus and its associated symptoms such as inflammation?
What is the microbiome?
As recorded in Wikipedia, the human microbiome represents the totality of all microbiota residing on or within human tissues and biofluids along with other associated anatomical sites where they exist, such as the skin, mammary glands, placenta, gastrointestinal tract, biliary tract, etc. Types of human microbiota include bacteria, archaea, fungi, protists and viruses. In the field of genomics, the term human microbiome may refer to the collective genomes of resident microorganisms.
The National Institute of Health’s Human Microbiome Project represents the Common Fund’s Human Microbiome Project (HMP), enabling the study of the microbial communities that reside in and on the human body, as well as the roles they play in human health and disease.
As it turns out, not all microbes in the gut are the same. Some turn out to be positive while others are negative and even neutral, while some might represent a hostile presence. While most are what is known as symbiotic (the microbe and the person benefits), others may be associated with disease.
According to the Human Microbiome Project mentioned above, healthy humans have about 80-85% good and neutral bacteria with the remainder negative. If these rations flip upside down, due to any number of factors from diet, aging, lifestyle, illness, and the like, the net result is degradation in overall health.
What is the name of the study?
Gut Microbiota composition reflects disease severity and dysfunctional immune responses in patients with COVID-19.
What was the overall study method involved?
The study team in Hong Kong conducted a two-hospital cohort study, taking samples (blood, stool, etc.) and patient records associated with 100 patients diagnosed with positive, laboratory-confirmed SARS-CoV-2 infection. A total of 27 stool samples were collected out of the 100 total number of patients for up to 30 days after viral clearance. The study team employed use of shotgun sequencing total DNA extracted from stools while inflammatory cytokines and blood marker concentration amounts were derived from plasma samples.
What is significant about this Hong Kong study?
Published in journal Gut just last month, this is one of the first research endeavors to evidence that those with COVID-19 may manifest different gut microbiomes than those people that don’t have COVID-19. Generally, this team observed that ‘good’ bacteria that are associated with positive immune system response are significantly deficient in COVID-19 patients, such as Bifidobacterium, Eubacterium rectale, and F. prausnitzii.
Is there a connection between the microbiome and so-called Long Covid?
According to this research, there is a distinct possibility. Those good, positive bacteria, again such as Bifidobacterium and F. prausnitzii and others, are woefully low even well after viral clearance. Hence, those symptoms associated with this phenomenon, from fatigue and shortness of breath to headaches and joint pain could actually represent an ongoing dysbiotic gut microbiome scenario.
What are some observations made by this study team?
That those individuals infected with COVID-19 seem to have higher numbers of noxious bacteria than do those that haven’t been infected by the pathogen. An example is that those infected with COVID-19 had higher markers such as bacterium R. gnavus—linked to inflammatory bowel diseases—typically takes up <0.1 % of a healthy gut but appears to abound during COVID-19. Moreover, the Hong Kong team measured greater amounts of R. torques (which is associated with autism, sleep disorders, etc.) as well as the bacteria B.dorei associated with chronic kidney disease as well as autoimmune disorders.
The Research Center
The Inflammatory Bowel Disease and Microbiota, Institute of Digestive Disease at The Chinese University of Hong Kong is led by Professor Siew Ng where the team conducts comprehensive research both locally and internationally.
Professor Siew C. Ng, Medicine and Therapeutics, The Chinese University of Hong Kong, Corresponding Author
Call to Action: Contact the corresponding author at [email protected]
For other researchers/authors, follow the link to the underlying source at Journal Gut.