In a recent study published on the preprint server medRxiv*, researchers explored the gut microbiome and post-illness metabolomic profiles of community-acquired coronavirus disease 2019 (COVID-19) cases and people with long-lasting non-COVID-19 illnesses .
Study: Gut microbiome and metabolomic profiling across the community-based spectrum of COVID and non-COVID disease: a COVID-19 biobank study. Image credit: Troyan/Shutterstock
background
Studies have reported several cases of community-managed mild and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections; however, severe cases of COVID-19 have been reported among people prone to cardiovascular disease. There has been growing concern about the long duration of symptoms of COVID-19 in many people, including cases managed in the communities. However, the risk factors and biological variables associated with prolonged duration of COVID-19 symptoms have not been well characterized.
About the study
In the present study, the researchers investigated whether the metabolomic profiles of community-dwelling individuals differed from those with variable duration of COVID-19 symptoms.
The team also investigated whether the composition of the faecal microbiome obtained after acute illness differs between people with illness of varying duration of symptoms with or without a history of COVID-19. In addition, the team assessed the likely association between gut metagenomic composition and the metabolomic profiles of the study participants.
CSSB study participants (Covid Symptom Study Biobank) were recruited and classified as (i) asymptomatic COVID-19 group; (ii) short duration of COVID-19 (≤2 weeks); (iii) long duration of COVID-19 (≥28 days); and (iv) long duration of symptoms (≥28 days) of non-COVID-19 illnesses. Long COVID groups were recategorized as OCS28 (28 to 83 days) and post-COVID-19 syndrome (PCS84, >84 days).
The same parameters were applied for non-COVID-19 diseases and six groups were formed consisting of four COVID-19 groups as (i) asymptomatic; (ii) acute COVID-19 (≤1 week); (iii) PCS84 and (iv) OSC28; and two non-Covid-19 groups: non-Covid-19 illnesses for 28–83 days (NC28), non-Covid-19 illnesses for ≥84 days (NC84).
Capillary blood samples and faecal samples were obtained between November 2020 and January 2021 from all and some participants, respectively. Nuclear magnetic resonance metabolomic analysis of metabolites (n = 249, of which 37 were clinically validated) associated with hospitalization associated with COVID-19 was performed in March/April 2021.
Genomic deoxyribonucleic acid (gDNA) was extracted, then DNA libraries were prepared and sequenced, and metagenomic analysis was performed. A generalized linear model was used and Spearman’s correlation coefficients were calculated after controlling for confounding variables to determine the association between microbiome profiles and metabolome profiles of study participants, and assessed the Infectious Disease Risk Prediction (ID) scores.
results
Of 15,564 individuals who received e-mail invitations for the CSSB study, 37% (n=5694) were recruited for the present study, of which 84% (n=4787) of participants returned their samples to analyze their metabolomic profiles. The average age of the participants was 53 years, most of them (79%) were women, adequate data were obtained for 78% (n=3718) individuals and 81% (n=2561) could be categorized phenotypically.
Metabolite levels of 36% (n = 90/246) were different between the OSC28 group and the asymptomatic COVID-19 group, of which 43% (n = 39) differed between the NC28 group and the asymptomatic COVID-19 group . Of the 37 clinically validated metabolites, fatty acid levels differed between asymptomatic COVID-19 cases and symptomatic, non-COVID-19 participants.
Higher levels of polyunsaturated fatty acids (PUFA) were associated with lower odds of longer duration of COVID-19 (OR = 0.7 for OSC28 versus asymptomatic cases) and non-SARS-CoV-2 disease (OR = 0.7 for NC28 versus asymptomatic). Monounsaturated fatty acid (MUFA) levels were associated with prolonged COVID-19 (OR = 1.3 for OSC28 versus asymptomatic SARS-CoV-2 infection), and elevated triglycerides (TG) and high-density lipoprotein low-density lipoprotein (VLDL) were related to a prolonged period. diseases in participants with COVID-19 and non-COVID-19.
TG to phosphoglyceride ratios were also directly proportional to disease duration. In contrast, elevated levels of high-density lipoprotein (HDL) were linked to asymptomatic cases of COVID-19. Neither glycoprotein acetyls nor amino acid levels were related to duration of COVID-19 symptoms. Only 2.8% (n = 7) of variables differed significantly between long COVID groups (PCS84 and OSC28 combined) compared to non-COVID-19 disease groups (NC84 and NC28 combined).
Higher HDL values were observed for patients with acute COVID-19 (OR 1.2) compared to patients with non-COVID-19 disease, with even greater levels among the asymptomatic disease group (OR 1.4) compared to non-Covid-19 diseases. Larger ID scores were associated with longer symptom duration, and the impact of ID scores was slightly stronger after adjustments for hPDI (healthy plant-based diet index) with OR 1.6 and 1.5 with and without hPDI, respectively (OSC28 vs. asymptomatic COVID-19). ).
Microbial richness was not significantly different between people in the metabolomic subset (n = 301), except for species such as Streptococcus vestibularis, the bacterium Firmicutes CAG 94 Ruminococcus callidus and an atherogenic-dyslipidemic profile was associated with prolonged duration of COVID -19 and no. – COVID-19 diseases. No significant associations were found between disease duration and gut microbiome among convalescents.
Conclusion
Overall, the study findings highlighted the potential role of cardiometabolic dysfunction in the long-term experience of illness, including after COVID-19.
*Important news
medRxiv publishes preliminary scientific reports that are not peer-reviewed and therefore should not be considered conclusive, guide clinical practice/health-related behavior, or be treated as established information.