Thrombotic Mechanism Involving Platelet Activation, Hypercoagulability and Hypofibrinolysis in Coronavirus Disease 2019

Detection of Thrombosis Using Soluble C-Type Lectin-like Receptor-2 with D-Dimer Level and Platelet Count

Introduction: Soluble C-type lectin-like receptor -2 (sCLEC-2) has been recognized as a marker of platelet activation, and attention has been drawn to formulas combining sCLEC-2 levels with platelet count and D-dimer levels. Methods: In this study, sCLEC-2 levels, as well as sCLEC-2/platelet count (sCLEC-2/PLT), sCLEC-2 × D-dimer (sCLEC-2xDD), and sCLEc-2xDD/PLT formulas were used to detect thrombotic diseases, including microvascular thrombosis (MVT), arterial thromboembolism (ATE), and venous thromboembolism (VTE), with the aim of evaluating the ability of the three parameters combined in these formulas to diagnose thrombotic diseases. Results: The plasma sCLEC-2 levels were significantly higher in patients with infectious or thrombotic diseases than in those with neither thrombosis nor infection; however, there was no significant difference among patients with infection, ATE, VTE, and MVT; the correlations among sCLEC-2, platelet count, and D-dimer level were poor. The sCLEC-2/PLT ratio was the highest in patients with MVT, and the sCLEC-2 × D-dimer value was higher in patients with MVT and VTE than in those with neither thrombosis nor infection. Although receiver operating characteristic (ROC) analysis shows the differential diagnosis of thrombotic diseases from non-thrombosis without infection, the sCLEC-2 × D-dimer/platelet count was useful for differential diagnosis among MVT and infection or non-thrombotic diseases. Conclusions: sCLEC-2 is useful for the diagnosis of thrombosis, and the formulas of sCLEC-2 with platelet count or D-dimer are useful for the diagnosis of thrombosis using ROC analyses for the thrombosis group vs. the non-thrombosis group without infection.

Aberrant innate immune profile associated with COVID-19 mortality in Pretoria, South Africa

The African continent reported the least number of COVID-19 cases and deaths of all the continents, although the exact reasons for this are still unclear. In addition, little is known about the immunological profiles associated with COVID-19 mortality in Africa. The present study compared clinical and immunological parameters, as well as treatment outcomes in patients admitted with COVID-19 in Pretoria, South Africa, to determine if these parameters correlated with mortality in this population. The in-hospital mortality rate for the cohort was 15.79%. The mortality rate in people living with HIV (PLWH) was 10.81% and 17.16% in people without HIV (p = 0.395). No differences in age (p = 0.099), gender (p = 0.127) or comorbidities were found between deceased patients and those who survived. All four of the PLWH who died had a CD4+ T-cell count <200 cells/mm3, a significantly higher HIV viral load than those who survived (p = 0.009), and none were receiving antiretroviral therapy. Seven of 174 (4%) patients had evidence of auto-antibodies neutralizing Type 1 interferons (IFNs). Two of the them died, and their presence was significantly associated with mortality (p = 0.042). In the adjusted model, the only clinical parameters associated with mortality were: higher fraction of inspired oxygen (FiO2) (OR: 3.308, p = 0.011) indicating a greater need for oxygen, high creatinine (OR: 4.424, p = 0.001) and lower platelet counts (OR: 0.203, p = 0.009), possibly secondary to immunothrombosis. Overall, expression of the co-receptor CD86 (p = 0.021) on monocytes and percentages of CD8+ effector memory 2 T-cells (OR: 0.45, p = 0.027) was lower in deceased patients. Decreased CD86 expression impairs the development and survival of effector memory T-cells. Deceased patients had higher concentrations of RANTES (p = 0.003), eotaxin (p = 0.003) and interleukin (IL)-8 (p < 0.001), all involved in the activation and recruitment of innate immune cells. They also had lower concentrations of transforming growth factor (TGF)-β1 (p = 0.40), indicating an impaired anti-inflammatory response. The immunological profile associated with COVID-19 mortality in South Africa points to the role of aberrate innate immune responses.

Persistent hypofibrinolysis in severe COVID-19 associated with elevated fibrinolysis inhibitors activity

Hypercoagulability and reduced fibrinolysis are well-established complications associated with COVID-19. However, the timelines for the onset and resolution of these complications remain unclear. The aim of this study was to evaluate, in a cohort of COVID-19 patients, changes in coagulation and fibrinolytic activity through ROTEM assay at different time points during the initial 30 days following the onset of symptoms in both mild and severe cases. Blood samples were collected at five intervals after symptoms onset: 6-10 days, 11-15 days, 16-20 days, 21-25 days, and 26-30 days. In addition, fibrinogen, plasminogen, PAI-1, and alpha 2-antiplasmin activities were determined. Out of 85 participants, 71% had mild COVID-19. Twenty uninfected individuals were evaluated as controls. ROTEM parameters showed a hypercoagulable state among mild COVID-19 patients beginning in the second week of symptoms onset, with a trend towards reversal after the third week of symptoms. In severe COVID-19 cases, hypercoagulability was observed since the first few days of symptoms, with a tendency towards reversal after the fourth week of symptoms onset. A hypofibrinolytic state was identified in severe COVID-19 patients from early stages and persisted even after 30 days of symptoms. Elevated activity of PAI-1 and alpha 2-antiplasmin was also detected in severe COVID-19 patients. In conclusion, both mild and severe cases of COVID-19 exhibited transient hypercoagulability, reverted by the end of the first month. However, severe COVID-19 cases sustain hypofibrinolysis throughout the course of the disease, which is associated with elevated activity of fibrinolysis inhibitors. Persistent hypofibrinolysis could contribute to long COVID-19 manifestations.

COVID-19 and abnormal uterine bleeding: potential associations and mechanisms

The impact of COVID-19 on menstruation has received a high level of public and media interest. Despite this, uncertainty exists about the advice that women and people who menstruate should receive in relation to the expected impact of SARS-CoV-2 infection, long COVID or COVID-19 vaccination on menstruation. Furthermore, the mechanisms leading to these reported menstrual changes are poorly understood. This review evaluates the published literature on COVID-19 and its impact on menstrual bleeding, discussing the strengths and limitations of these studies. We present evidence consistent with SARS-CoV-2 infection and long COVID having an association with changes in menstrual bleeding parameters and that the impact of COVID vaccination on menstruation appears less significant. An overview of menstrual physiology and known causes of abnormal uterine bleeding (AUB) is provided before discussing potential mechanisms which may underpin the menstrual disturbance reported with COVID-19, highlighting areas for future scientific study. Finally, consideration is given to the effect that menstruation may have on COVID-19, including the impact of the ovarian sex hormones on acute COVID-19 severity and susceptibility and reported variation in long COVID symptoms across the menstrual cycle. Understanding the current evidence and addressing gaps in our knowledge in this area are essential to inform public health policy, direct the treatment of menstrual disturbance and facilitate development of new therapies, which may reduce the severity of COVID-19 and improve quality of life for those experiencing long COVID.

Whole blood viscoelastic testing profile and mortality in patients hospitalized with acute COVID-19 pneumonia: A systematic review and meta-analysis

BACKGROUND

Several studies have evaluated the possible association between whole blood viscoelastic testing (VET) parameters in patients hospitalized for acute Coronavirus disease 2019 (COVID-19) pneumonia and mortality. A few studies found no significant differences between survivors and non-survivors, though other studies identified potential predictors of COVID-19-related mortality. We conducted a systematic review and meta-analysis of the literature to evaluate the possible association between standard thromboelastometry/graphy parameters and mortality in patients hospitalized for acute COVID-19 pneumonia.

METHODS

Relevant studies were searched through MEDLINE, EMBASE, and Google Scholar from their inception until 15th June 2023. We aimed to identify any study including: i) adults admitted to intensive care units (ICU) or medicine wards (MW) for acute COVID-19 pneumonia; ii) viscoelastic testing; iii) mortality.

RESULTS

We included 13 studies: nine prospective and four retrospective, 231 (30.4 %) non-survivors and 528 (69.6 %) survivors. Mortality rates ranged from 12.8 % to 67.5 %. The studies using the TEG apparatus found a significant difference in K time in the Kaolin test among survivors vs. non-survivors (mean difference [MD] 0.20, 95 % confidence interval [CI] 0.12, 0.28, I2 0%). The studies using the rotational thromboelastometry apparatus found a significant difference in CT-INTEM (MD -17.14, 95 % CI -29.23, -5.06, I2 0%) and LI60-EXTEM (MD -1.00, 95 % CI -1.00, -1.00, I2 0%) assays among survivors vs. non-survivors.

CONCLUSION

We identified no specific hypercoagulable or hypocoagulable profile associated with mortality in patients with COVID-19-related pneumonia. Large prospective studies are needed to explore the possible prognostic role of VET in this subset of patients.

Super Formula for Soluble C-Type Lectin-Like Receptor 2 × D-Dimer in Patients With Acute Cerebral Infarction

Acute cerebral infarction (ACI) includes atherosclerotic and cardiogenic ACI and involves a thrombotic state, requiring antithrombotic treatment. However, the thrombotic state in ACI cannot be evaluated using routine hemostatic examinations. Plasma soluble C-type lectin-like receptor 2 (sCLEC-2) and D-dimer levels were measured in patients with ACI. Plasma sCLEC-2 and D-dimer levels were significantly higher in patients with ACI than in those without it. The sCLEC-2 × D-dimer formula was significantly higher in patients with ACI than in those without it. A receiver operating characteristic curve showed a high sensitivity, area under the curve, and odds for diagnosing ACI in the sCLEC-2 × D-dimer formula. Although the sCLEC-2 and D-dimer levels were useful for the differential diagnosis between cardiogenic and atherosclerotic ACI, the sCLEC-2 × D-dimer formula was not useful. sCLEC2 and D-dimer levels are useful for the diagnosis of ACI and the sCLEC2 × D-dimer formula can enhance the diagnostic ability of ACI, and sCLEC2 and D-dimer levels may be useful for differentiating between atherosclerotic and cardioembolic ACI.

Navigating the Post-COVID-19 Immunological Era: Understanding Long COVID-19 and Immune Response

The COVID-19 pandemic has affected the world unprecedentedly, with both positive and negative impacts. COVID-19 significantly impacted the immune system, and understanding the immunological consequences of COVID-19 is essential for developing effective treatment strategies. The purpose of this review is to comprehensively explore and provide insights into the immunological aspects of long COVID-19, a phenomenon where individuals continue to experience a range of symptoms and complications, even after the acute phase of COVID-19 infection has subsided. The immune system responds to the initial infection by producing various immune cells and molecules, including antibodies, T cells, and cytokines. However, in some patients, this immune response becomes dysregulated, leading to chronic inflammation and persistent symptoms. Long COVID-19 encompasses diverse persistent symptoms affecting multiple organ systems, including the respiratory, cardiovascular, neurological, and gastrointestinal systems. In the post-COVID-19 immunological era, long COVID-19 and its impact on immune response have become a significant concern. Post-COVID-19 immune pathology, including autoimmunity and immune-mediated disorders, has also been reported in some patients. This review provides an overview of the current understanding of long COVID-19, its relationship to immunological responses, and the impact of post-COVID-19 immune pathology on patient outcomes. Additionally, the review addresses the current and potential treatments for long COVID-19, including immunomodulatory therapies, rehabilitation programs, and mental health support, all of which aim to improve the quality of life for individuals with long COVID-19. Understanding the complex interplay between the immune system and long COVID-19 is crucial for developing targeted therapeutic strategies and providing optimal care in the post-COVID-19 era.

Biomarkers of Hypercoagulability in COVID-19

This issue focuses on the pathophysiology of coronavirus disease 2019 (COVID-19) [...].