Persistent endotheliopathy in the pathogenesis of long COVID syndrome: Comment from von Meijenfeldt et al

[Interaction of somatic findings and psychiatric symptoms in COVID-19. A scoping review]

An infection with SARS-CoV‑2 can affect the central nervous system, leading to neurological as well as psychiatric symptoms. In this respect, mechanisms of inflammation seem to be of much greater importance than the virus itself. This paper deals with the possible contributions of organic changes to psychiatric symptomatology and deals especially with delirium, cognitive symptoms, depression, anxiety, posttraumatic stress disorder and psychosis. Processes of neuroinflammation with infection of capillary endothelial cells and activation of microglia and astrocytes releasing high amounts of cytokines seem to be of key importance in all kinds of disturbances. They can lead to damage in grey and white matter, impairment of cerebral metabolism and loss of connectivity. Such neuroimmunological processes have been described as a organic basis for many psychiatric disorders, as affective disorders, psychoses and dementia. As the activation of the glia cells can persist for a long time after the offending agent has been cleared, this can contribute to long term sequalae of the infection.

Prolonged platelet hyperactivity after COVID-19 infection

Platelet hyperactivity often occurs in patients with coronavirus disease 2019 (COVID-19). However, it remains unclear how long platelet hyperactivity lasts after the acute phase, owing to a lack of follow-up studies. To elucidate the course of platelet hyperactivity, we serially measured platelet activity in patients with COVID-19 up to 40 days after hospital admission using an easily assessable haematology analyser that semi-quantitates platelet clumps on a scattergram. Our results showed that platelet hyperactivity persisted for at least 40 days even after acute inflammation subsided in most patients with COVID-19, regardless of disease severity. Persistent platelet hyperactivity may contribute to thromboembolic complications in post-COVID-19 patients.

Quality of life and ability to work of patients with Post-COVID syndrome in relation to the number of existing symptoms and the duration since infection up to 12 months: a cross-sectional study

PURPOSE

Following SARS-CoV-2 virus infection, patients may suffer from long-lasting symptoms regardless of disease severity. Preliminary results show limitations in health-related quality of life (HRQoL). The aim of this study is to show a possible change depending on the duration since infection and the accumulation of symptoms. Additionally, other possible influencing factors will be analyzed.

METHODS

The study population consisted of patients (18-65 years) presenting to the Post-COVID outpatient clinic of the University Hospital Jena, Germany, between March and October 2021. The HRQoL was assessed by the use of the RehabNeQ and the SF-36. Data analysis was descriptive with frequencies, means, and/or percentages. In addition, a univariate analysis of variance was performed to show the dependence of physical and psychological HRQoL on specific factors. This was finally tested for significance at an alpha level of 5%.

RESULTS

Data from 318 patients were analyzed, most of whom had 3-6 months of infection (56%) and 5-10 symptoms persisted (60.4%). Both mental (MCS) and physical sum score (PCS) of HRQoL were significantly lower than those of the German normal population (p < .001). The number of remaining symptoms (MCS p = .0034, PCS p = .000) as well as the perceived ability to work (MCS p = .007, PCS p = .000) influenced the HRQoL.

CONCLUSION

The HRQoL of patients with Post-COVID-syndrome is still reduced months after infection and so is their occupational performance. In particular, the number of symptoms could have an influence on this deficit, which would need to be further investigated. Further research is needed to detect other factors influencing HRQoL and to implement appropriate therapeutic interventions.

The suboptimal fibrinolytic response in COVID-19 is dictated by high PAI-1

BACKGROUND

Severe COVID-19 disease is associated with thrombotic complications and extensive fibrin deposition. This study investigates whether the hemostatic complications in COVID-19 disease arise due to dysregulation of the fibrinolytic system.

METHODS

This prospective study analyzed fibrinolytic profiles of 113 patients hospitalized with COVID-19 disease with 24 patients with non-COVID-19 respiratory infection and healthy controls. Antigens were quantified by Ella system or ELISA, clot lysis by turbidimetric assay, and plasminogen activator inhibitor-1 (PAI-1)/plasmin activity using chromogenic substrates. Clot structure was visualized by confocal microscopy.

RESULTS

PAI-1 and its cofactor, vitronectin, are significantly elevated in patients with COVID-19 disease compared with those with non-COVID-19 respiratory infection and healthy control groups. Thrombin activatable fibrinolysis inhibitor and tissue plasminogen activator were elevated in patients with COVID-19 disease relative to healthy controls. PAI-1 and tissue plasminogen activator (tPA) were associated with more severe COVID-19 disease severity. Clots formed from COVID-19 plasma demonstrate an altered fibrin network, with attenuated fiber length and increased branching. Functional studies reveal that plasmin generation and clot lysis were markedly attenuated in COVID-19 disease, while PAI-1 activity was elevated. Clot lysis time significantly correlated with PAI-1 levels. Stratification of COVID-19 samples according to PAI-1 levels reveals significantly faster lysis when using the PAI-1 resistant (tPA) variant, tenecteplase, over alteplase lysis.

CONCLUSION

This study shows that the suboptimal fibrinolytic response in COVID-19 disease is directly attributable to elevated levels of PAI-1, which attenuate plasmin generation. These data highlight the important prognostic potential of PAI-1 and the possibility of using pre-existing drugs, such as tenecteplase, to treat COVID-19 disease and potentially other respiratory diseases.

Protection by metformin against severe Covid-19: an in-depth mechanistic analysis

Since the outbreak of Covid-19, several observational studies on diabetes and Covid-19 have reported a favourable association between metformin and Covid-19-related outcomes in patients with type 2 diabetes mellitus (T2DM). This is not surprising since metformin affects many of the pathophysiological mechanisms implicated in SARS-CoV-2 immune response, systemic spread and sequelae. A comparison of the multifactorial pathophysiological mechanisms of Covid-19 progression with metformin's well-known pleiotropic properties suggests that the treatment of patients with this drug might be particularly beneficial. Indeed, metformin could alleviate the cytokine storm, diminish virus entry into cells, protect against microvascular damage as well as prevent secondary fibrosis. Although our in-depth analysis covers many potential metformin mechanisms of action, we want to highlight more particularly its unique microcirculatory protective effects since worsening of Covid-19 disease clearly appears as largely due to severe defects in the structure and functioning of microvessels. Overall, these observations confirm that metformin is a unique, pleiotropic drug that targets many of Covid-19′s pathophysiology processes in a diabetes-independent manner.

Impaired exercise capacity in post-COVID syndrome: the role of VWF-ADAMTS13 axis

A VWF(Ag)/ADAMTS13 ratio ≥1.5 was evident in 28% of the PCS cohort.

Of the patients with impaired exercise capacity, 55% had a VWF(Ag)/ADAMTS13 ratio ≥1.5 (odds ratio, 4).

Post-COVID syndrome (PCS), or long COVID, is an increasingly recognized complication of acute SARS-CoV-2 infection, characterized by persistent fatigue, reduced exercise tolerance, chest pain, shortness of breath, and cognitive slowing. Acute COVID-19 is strongly linked with an increased risk of thrombosis, which is a prothrombotic state quantified by an elevated von Willebrand factor (VWF) antigen (Ag)/ADAMTS13 ratio that is associated with severity of acute COVID-19 infection. We investigated whether patients with PCS also had evidence of a prothrombotic state associated with symptom severity. In a large cohort of patients referred to a dedicated post-COVID-19 clinic, thrombotic risk, including VWF(Ag)/ADAMTS13 ratio, was investigated. An elevated VWF(Ag)/ADAMTS13 ratio (≥1.5) was present in nearly one-third of the cohort and was 4 times more likely to be present in patients with impaired exercise capacity, as evidenced by desaturation ≥3% and/or an increase in lactate level >1 from baseline on a 1-minute sit-to-stand test and/or a 6-minute walk test (P < .0001). Of 276 patients, 56 (20%) had impaired exercise capacity, of which 55% (31/56) had a VWF(Ag)/ADAMTS13 ratio ≥1.5 (P < .0001). Factor VIII and VWF(Ag) were elevated in 26% and 18%, respectively, and support a hypercoagulable state in some patients with PCS. These findings suggest possible ongoing microvascular/endothelial dysfunction in the pathogenesis of PCS and suggest a role for antithrombotic therapy in the treatment of these patients.