COVID-19 infection-associated platelet and neutrophil activation is blunted by previous anti-SARS-CoV-2 vaccination.

The effectiveness of vaccination against SARS-CoV-2 in preventing COVID-19 or in reducing severe illness in subjects hospitalized for COVID-19 despite vaccination has been unequivocally shown. However, no studies so far have assessed if subjects who get COVID-19 despite vaccination are protected from SARS-CoV-2-induced platelet, neutrophil and endothelial activation, biomarkers associated with thrombosis and worse outcome. In this pilot study, we show that previous vaccination blunts COVID-19-associated platelet activation, assessed by circulating platelet-derived microvesicles and soluble P-selectin, and neutrophil activation, assessed by circulating neutrophil extracellular trap (NET) biomarkers and matrix metalloproteinase-9, and reduces COVID-19-associated thrombotic events, hospitalization in intensive-care units and death.

Association of Neutrophil Activation, More Than Platelet Activation, With Thrombotic Complications in Coronavirus Disease 2019.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 infection is associated with hypercoagulability, which predisposes to venous thromboembolism (VTE). We analyzed platelet and neutrophil activation in patients with coronavirus disease 2019 (COVID-19) and their association with VTE. METHODS: Hospitalized patients with COVID-19 and age- and sex-matched healthy controls were studied. Platelet and leukocyte activation, neutrophil extracellular traps (NETs), and matrix metalloproteinase 9, a neutrophil-released enzyme, were measured. Four patients were restudied after recovery. The activating effect of plasma from patients with COVID-19 on control platelets and leukocytes and the inhibiting activity of common antithrombotic agents on it were studied. RESULTS: A total of 36 patients with COVID-19 and 31 healthy controls were studied; VTE developed in 8 of 36 patients with COVID-19 (22.2%). Platelets and neutrophils were activated in patients with COVID-19. NET, but not platelet activation, biomarkers correlated with disease severity and were associated with thrombosis. Plasmatic matrix metalloproteinase 9 was significantly increased in patients with COVID-19. Platelet and neutrophil activation markers, but less so NETs, normalized after recovery. In vitro, plasma from patients with COVID-19 triggered platelet and neutrophil activation and NET formation, the latter blocked by therapeutic-dose low-molecular-weight heparin, but not by aspirin or dypiridamole. CONCLUSIONS: Platelet and neutrophil activation are key features of patients with COVID-19. NET biomarkers may help to predict clinical worsening and VTE and may guide low-molecular-weight heparin treatment.

Search for SARS-CoV-2 RNA in platelets from COVID-19 patients.

The frequent finding of thrombocytopenia in patients with severe SARS-CoV-2 infection (COVID-19) and previous evidence that several viruses enter platelets suggest that SARS-CoV-2 might be internalized by platelets of COVID-19. Aim of our study was to assess the presence of SARS-CoV-2 RNA in platelets from hospitalized patients with aconfirmed diagnosis of COVID-19. RNA was extracted from platelets, leukocytes and serum from 24 COVID-19 patients and 3 healthy controls, real-time PCR and ddPCR for viral genes were carried out. SARS-CoV-2 RNA was not detected in any of the samples analyzed nor in healthy controls, by either RT-PCR or ddPCR, while RNA samples from nasopharyngeal swabs of COVID-19 patients were correctly identified. Viral RNA was not detected independently of viral load, of positive nasopharyngeal swabs, or viremia, the last detected in only one patient (4.1%). SARS-CoV-2 entry in platelets is not acommon phenomenon in COVID-19 patients, differently from other viral infections.

Prediction of major bleeding in patients receiving DOACs for venous thromboembolism: A prospective cohort study.

BACKGROUND: In the direct oral anticoagulants (DOACs) era, extended anticoagulation is an attractive strategy after venous thromboembolism (VTE). The role of currently available bleeding risk scores for VTE patients treated with DOACs in clinical practice is undefined. METHODS: Consecutive patients with VTE were included in a prospective multicenter cohort at the initiation of treatment with DOACs. The role of ATRIA, HAS-BLED, Kuijer, ORBIT, RIETE and VTE-BLEED scores in predicting major bleeding (ISTH definition) while on DOAC treatment was assessed. RESULTS: Overall, 1034 patients were included and followed for one year or until the end of treatment or the occurrence of major bleeding. During study period, 26 major bleedings occurred in 25 patients (2.8% patient-year). Anemia, bleeding history and creatinine clearance <60 ml/min were significant predictors of major bleedings. The predictive value of bleeding risk scores was modest. In the 12-month study period, ORBIT (HR intermediate-high vs. low risk patients 3.62, 95% CI 1.65-7.94 and c-statistics 0.645, 95% CI 0.523-0.767) and VTE-BLEED (HR high vs. low 16.11, 95% CI 2.18-119.09 and c-statistics 0.674, 95% CI 0.593-0.755) score significantly predicted major bleeding. The lowest incidence of major bleeding (0.3%) was observed in the low-risk category of VTE-BLEED, while the highest (7.1%) in the high-risk category of ORBIT. CONCLUSIONS: In a real-life cohort of patients with VTE treated with DOACs, the predictive value of currently available bleeding risk scores was modest and not statistically different. Whether these scores can be used for decision making on anticoagulation should be assessed in management studies.

The role of statins in stroke.

Although evidence from epidemiological studies examining a relationship between cholesterol level and stroke is less than definitive, there is a compelling evidence from the clinical therapy trials primarily designed to examine the coronary benefits of statins that statin therapy also causes a reduction in the risk of stroke. Even though a stroke does not have the same exact pathophysiology as a heart attack, specific trials in stroke patients confirm advantages and risks of statin therapy in this kind of population. In primary prevention, statins are effective both when low-density lipoprotein (LDL) is raised and when hs-CRP is elevated. In secondary prevention, an absolute reduction of recurrent stroke can be obtained with statins, with a number needed to treat at 5 years of 45.