Gut microbiota composition is altered in postural orthostatic tachycardia syndrome and post-acute COVID-19 syndrome

Postural Orthostatic Tachycardia Syndrome (POTS) reflects an autonomic dysfunction, which can occur as a complication to COVID-19. Our aim was to examine gastrointestinal symptoms and gut microbiota composition in patients with POTS and post-acute COVID-19 syndrome (PACS), compared with controls. POTS patients (n = 27), PACS patients (n = 32) and controls (n = 39) delivered fecal samples and completed a 4-day food diary, irritable bowel syndrome-severity scoring system (IBS-SSS), and visual analog scale for IBS (VAS-IBS). A total of 98 DNA aliquots were sequenced to an average depth of 28.3 million (M) read pairs (Illumina 2 × 150 PE) per sample. Diversity and taxonomic levels of the microbiome, as well as functional abundances were calculated for POTS and PACS groups, then compared with controls. There were several differences in taxonomic composition between POTS and controls, whereas only the abundance of Ascomycota and Firmicutes differed between PACS and controls. The clinical variables total IBS-SSS, fatigue, and bloating and flatulence significantly correlated with multiple individual taxa abundances, alpha diversity, and functional abundances. We conclude that POTS, and to a less extent PACS, are associated with differences in gut microbiota composition in diversity and at several taxonomic levels. Clinical symptoms are correlated with both alpha diversity and taxonomic and functional abundances.

Anxiety and depression symptoms among patients with long COVID: a retrospective cohort study

Patients suffering from post-acute sequelae of COVID-19 (PASC) have a higher prevalence of anxiety and depression than the general population. The long-term trajectory of these sequelae is still unfolding. To assess the burden of anxiety and depression among patients presenting to the University of Iowa Hospitals and Clinics (UIHC) post-COVID-19 clinic, we analyzed how patient factors influenced Generalized Anxiety Disorder-7 (GAD-7) and Patient Health Questionnaire-9 (PHQ-9) scores. In this retrospective cohort study, the GAD-7 and PHQ-9 questionnaire scores of patients presenting to the UIHC post-COVID clinic between March 2021-February 2022 (N = 455) were compared to the scores of a sample of patients presenting to the general internal medicine (GIM) clinic during the same period (N = 94). Our analysis showed that patients with an absent history of depression on their electronic medical record (EMR) problem list scored significantly higher on the GAD-7 (mean difference -1.62, 95% CI -3.12 to -0.12, p = 0.034) and PHQ-9 (mean difference -4.45, 95% CI -5.53 to -3.37, p < 0.001) questionnaires compared to their similar counterparts in the GIM clinic. On the other hand, patients with an absent history of anxiety on their EMR problem list scored significantly higher on the GAD-7 (mean difference -2.90, 95% CI -4.0 to -1.80, p < 0.001) but not on the PHQ-9 questionnaire (p = 0.196). Overall, patients with PASC may have experienced a heavier burden of newly manifest anxiety and depression symptoms compared to patients seen in the GIM clinic. This suggests that the mental health impacts of PASC may be more pronounced in patients with no prior history of anxiety or depression.

Acute to post-acute COVID-19 thromboinflammation persistence: Mechanisms and potential consequences

Concerns for the long-term effects of COVID-19 infection have grown due to frequently reported persisting symptoms that can affect multiple systems for longer than 4 weeks after initial infection, a condition known as long-COVID-19 or post-acute COVID-19 syndrome (PACS). Even nonhospitalized survivors have an elevated risk for the development of thromboinflammatory-associated events, such as ischemic stroke and heart failure, pulmonary embolism and deep vein thrombosis. Recent findings point to the persistence of many mechanisms of hypercoagulability identified to be associated with disease severity and mortality in the acute phase of the disease, such as sustained inflammation and endotheliopathy, accompanied by abnormal fibrin generation and impaired fibrinolysis. Platelets seem to be central to the sustained hypercoagulable state, displaying hyperreactivity to stimuli and increased adhesive capacity. Platelets also contribute to elevated levels of thromboinflammatory mediators and pro-coagulant extracellular vesicles in individuals with ongoing PACS. Despite new advances in the understanding of mechanisms sustaining thromboinflammation in PACS, little is known about what triggers this persistence. In this graphical review, we provide a schematic representation of the known mechanisms and consequences of persisting thromboinflammation in COVID-19 survivors and summarize the hypothesized triggers maintaining this prothrombotic state.

Investigation of liquid biopsy analytes in peripheral blood of individuals after SARS-CoV-2 infection

BACKGROUND

Post-acute COVID-19 syndrome (PACS) is linked to severe organ damage. The identification and stratification of at-risk SARS-CoV-2 infected individuals is vital to providing appropriate care. This exploratory study looks for a potential liquid biopsy signal for PACS using both manual and machine learning approaches.

METHODS

Using a high definition single cell assay (HDSCA) workflow for liquid biopsy, we analysed 100 Post-COVID patients and 19 pre-pandemic normal donor (ND) controls. Within our patient cohort, 73 had received at least 1 dose of vaccination prior to SARS-CoV-2 infection. We stratified the COVID patients into 25 asymptomatic, 22 symptomatic COVID-19 but not suspected for PACS and 53 PACS suspected. All COVID-19 patients investigated in this study were diagnosed between April 2020 and January 2022 with a median 243 days (range 16-669) from diagnosis to their blood draw. We did a histopathological examination of rare events in the peripheral blood and used a machine learning model to evaluate predictors of PACS.

FINDINGS

The manual classification found rare cellular and acellular events consistent with features of endothelial cells and platelet structures in the PACS-suspected cohort. The three categories encompassing the hypothesised events were observed at a significantly higher incidence in the PACS-suspected cohort compared to the ND (p-value < 0.05). The machine learning classifier performed well when separating the NDs from Post-COVID with an accuracy of 90.1%, but poorly when separating the patients suspected and not suspected of PACS with an accuracy of 58.7%.

INTERPRETATION

Both the manual and the machine learning model found differences in the Post-COVID cohort and the NDs, suggesting the existence of a liquid biopsy signal after active SARS-CoV-2 infection. More research is needed to stratify PACS and its subsyndromes.

FUNDING

This work was funded in whole or in part by Fulgent Genetics, Kathy and Richard Leventhal and Vassiliadis Research Fund. This work was also supported by the National Cancer InstituteU54CA260591.