In a recent study posted to the medRxiv* preprint server, researchers explored post-illness gut-microbiome and metabolomic profiles of community coronavirus disease 2019 (COVID-19) cases and individuals with non-COVID-19 illnesses of prolonged duration.

Study: Metabolomic and gut microbiome profiles across the spectrum of community-based COVID and non-COVID disease: A COVID-19 Biobank study. Image Credit: Troyan/Shutterstock

Background

Studies have reported several cases of mild severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections managed within the communities; nevertheless, severe COVID-19 cases have been reported amongst individuals susceptible to cardiovascular illness. There have been growing concerns over the long duration of COVID-19 symptoms in lots of individuals, including those cases managed in communities. Nonetheless, risk aspects and biological variables related to prolonged COVID-19 symptom duration haven’t been well-characterized.

Concerning the study

In the current study, researchers investigated if metabolomic profiles of community-residing individuals differed from those with various duration of COVID-19 symptoms.

The team also investigated if the composition of the fecal microbiome obtained post-acute illness differed between individuals with diseases of various duration of symptoms with or without prior COVID-19 history. Moreover, the team assessed the probable association between the gut metagenomic composition and metabolomic profiles of the study participants.

Participants of the CSSB (COVID symptom study biobank) study were recruited and categorized as (i) asymptomatic COVID-19 group; (ii) short COVID-19 duration (≤2 weeks); (iii) long COVID-19 duration (≥28 days); and (iv) long symptom duration (≥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 identical parameters were applied for non-COVID-19 illnesses, and 6 groups were formed comprising 4 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 fecal samples were obtained between November 2020 and January 2021 from all and a couple of participants, respectively. Nuclear magnetic resonance metabolomic evaluation of metabolites (n=249, of which 37 were clinically validated) related to COVID-19-associated hospitalization was performed in March/April 2021.

Genomic deoxyribonucleic acid (gDNA) was extracted, following which DNA libraries were prepared and sequenced, and metagenomic evaluation was performed. Generalized linear modeling was used, and spearman correlation coefficients were calculated after controlling for confounding variables to find out the association between the microbiome profiles and metabolome profiles of the study participants, and the infectious diseases risk prediction (ID) scores were evaluated.

Results

Of 15,564 individuals who received email invites for the CSSB study, 37% (n=5694) were recruited for the current study, of which 84% (n=4787) of participants returned their samples for analyzing their metabolomic profiles. The common 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) might be phenotypically categorized.

The degrees of 36% (n=90/246) metabolites were different among the many OSC28 group and the asymptomatic COVID-19 group, of which 43% (n=39) differed among the many NC28 group and the asymptomatic COVID-19 group. Of the 37 clinically validated metabolites, fatty acid levels differed amongst asymptomatic COVID-19 cases and the symptomatic COVID-19 and non-COVID-19 participants.

Higher polyunsaturated fatty acids (PUFA) levels were related to lesser probabilities of longer COVID-19 duration (OR= 0.7 for OSC28 versus asymptomatic cases) and non-SARS-CoV-2 illnesses (OR=0.7 for NC28 versus asymptomatic). The monounsaturated fatty acids (MUFA) levels were related to prolonged COVID-19 (OR=1.3 for OSC28 versus asymptomatic SARS-CoV-2 infection), and elevated triglycerides (TG) and really low-density lipoproteins (VLDL) were related to prolonged illnesses in COVID-19 and non-COVID-19 participants.

TG to phosphoglycerides ratios were also directly proportional to the duration of illness. Contrastingly, elevated high-density lipoprotein (HDL) levels were related to asymptomatic COVID-19 cases. Neither glycoprotein acetyls nor amino acid levels were related to the duration of COVID-19 symptoms. Only 2.8% (n=7) variables significantly differed amongst long COVID groups (PCS84 and OSC28 combined) as compared to non-COVID-19 illness groups (NC84 and NC28 combined).

Higher HDL values were noted for acute COVID-19 patients (OR 1.2) in comparison with non-COVID-19 illness patients, with even greater levels among the many asymptomatic illness group (OR 1.4) in comparison with non-COVID-19 illnesses. Greater ID scores were related to prolonged symptom durations, and the impact of ID scores was barely stronger post- hPDI (healthy plant-based eating regimen index) adjustments with ORs 1.6 and 1.5 with and without hPDI, respectively (OSC28 vs. asymptomatic COVID-19).

Microbial richness was not significantly different among the many metabolomic subset individuals (n=301), apart from species resembling Streptococcus vestibularis, Firmicutes bacterium CAG 94 Ruminococcus callidus, and an atherogenic-dyslipidaemic profile was related to a protracted duration of COVID-19 and non-COVID-19 illnesses. No significant associations were found between the duration of illness and the microbiome of the gut amongst convalescents.

Conclusion

Overall, the study findings highlighted the potential role of cardiometabolic dysfunction within the experience of long illness duration, including after COVID-19.

*Vital notice    

medRxiv publishes preliminary scientific reports that are usually not peer-reviewed and, due to this fact, shouldn’t be thought to be conclusive, guide clinical practice/health-related behavior, or treated as established information.