Endothelial dysfunction, oxidative stress and low-grade endotoxemia in COVID-19 patients hospitalised in medical wards.

BACKGROUND: Endothelial dysfunction, assessed by flow-mediated dilation (FMD), is related to poor prognosis in patients with COVID-19 pneumonia (CP). In this study, we explored the interplay among FMD, NADPH oxidase type 2 (NOX-2) and lipopolysaccharides (LPS) in hospitalised patients with CP, community acquired pneumonia (CAP) and controls (CT). METHODS: We enrolled 20 consecutive patients with CP, 20 hospitalised patients with CAP and 20 CT matched for sex, age, and main cardiovascular risk factors. In all subjects we performed FMD and collected blood samples to analyse markers of oxidative stress (soluble Nox2-derived peptide (sNOX2-dp), hydrogen peroxide breakdown activity (HBA), nitric oxide (NO), hydrogen peroxide (H2O2)), inflammation (TNF-α and IL-6), LPS and zonulin levels. RESULTS: Compared with controls, CP had significant higher values of LPS, sNOX-2-dp, H2O2,TNF-α, IL-6 and zonulin; conversely FMD, HBA and NO bioavailability were significantly lower in CP. Compared to CAP patients, CP had significantly higher levels of sNOX2-dp, H2O2, TNF-α, IL-6, LPS, zonulin and lower HBA. Simple linear regression analysis showed that FMD inversely correlated with sNOX2-dp, H2O2, TNF-α, IL-6, LPS and zonulin; conversely FMD was directly correlated with NO bioavailability and HBA. Multiple linear regression analysis highlighted LPS as the only predictor of FMD. CONCLUSION: This study shows that patients with COVID-19 have low-grade endotoxemia that could activate NOX-2, generating increased oxidative stress and endothelial dysfunction.

Distinct platelet crosstalk with adaptive and innate immune cells after adenoviral and mRNA vaccination against SARS-CoV-2.

BACKGROUND: Genetic-based COVID-19 vaccines have proved to be highly effective in reducing the risk of hospitalization and death. Because they were first distributed in a large-scale population, the adenoviral-based vaccines were linked to a very rare thrombosis with thrombocytopenia syndrome, and the interplay between platelets and vaccinations increasingly gained attention. OBJECTIVES: The objective of this article was to study the crosstalk between platelets and the vaccine-induced immune response. METHODS: We prospectively enrolled young healthy volunteers who received the mRNA-based vaccine, BNT162b2 (n = 15), or the adenovirus-based vaccine, AZD1222 (n = 25) and studied their short-term platelet and immune response before and after vaccine injections. In a separate cohort, we retrospectively analyzed the effect of aspirin on the antibody response 1 and 5 months after BNT162b2 vaccination. RESULTS: Here, we show that a faster antibody response to either vaccine is associated with the formation of platelet aggregates with marginal zone-like B cells, a subset geared to bridge the temporal gap between innate and adaptive immunities. However, although the mRNA-based vaccine is associated with a more gradual and tolerogenic response that fosters the crosstalk between platelets and adaptive immunity, the adenovirus-based vaccine, the less immunogenic of the 2, evokes an antiviral-like response during which the platelets are cleared and less likely to cooperate with B cells. Moreover, subjects taking aspirin (n = 56) display lower antibody levels after BNT162b2 vaccination compared with matched individuals. CONCLUSION: Platelets are a component of the innate immune pathways that promote the B-cell response after vaccination. Future studies on the platelet-immune crosstalk post-immunization will improve the safety, efficacy, and strategic administration of next-generation vaccines.

Association between PaO2/FiO2 ratio and thrombotic events in COVID-19 patients.

PaO2/FiO2 (P/F ratio) is considered a marker of hypoxia/hypoxemia and mortality. Several prothrombotic changes are associated with the decrease of P/F ratio. The role of P/F ratio in patients with arterial and venous thrombosis remains unclear. The aim of this study was to assess in patients with coronavirus disease 2019 (COVID-19), the association between P/F ratio and arterial/venous thrombosis. One thousand and four hundred and six COVID-19 patients were recruited; 289 (21%) patients had P/F ratio < 200 and 1117 (79%) ≥ 200. Compared to the patients with P/F ratio ≥ 200, those with P/F ratio < 200 were older and with higher levels of glycemia, D-dimer and lower levels of albumin. Multiple linear regression analysis showed that albumin (standardized coefficient ß:  0.156; SE: 0.001; p = 0.0001) and D-dimer (standardized coefficient ß: -0.135; SE: 0.0001; p = 0.0001) were associated with P/F ratio. During the hospitalization 159 patients were transferred in intensive care unit (ICU), 253 patients died, 156 patients had arterial or venous thrombotic events. A bivariate logistic analysis was performed to analyze the predictors of thrombosis in COVID-19 patients; P/F ratio < 200 (Odds Ratio: [OR] 1.718, 95% Confidence Interval [CI] 1.085-2.718, p = 0.021), albumin (OR 1.693, 95% CI 1.055-2.716, p = 0.029), D-dimer (OR 3.469, 95% CI 2.110-5.703, p < 0.0001), coronary artery disease (CAD) (OR 1.800, 95% CI 1.086-2.984, p = 0.023) and heart failure (OR 2.410 95% CI 1.385-4.193, p = 0.002) independently predicted thrombotic events in this population. This study suggests that the P/F ratio is associated with thrombotic events by promoting a hypercoagulation state in patients hospitalized for COVID-19.

Serological Response and Relationship with Gender-Sensitive Variables among Healthcare Workers after SARS-CoV-2 Vaccination.

Vaccine-induced immunity is a key strategy in the long-term control of the COVID-19 pandemic. The aim of our study was to explore the relationship between mRNA vaccine-induced antibodies and gender-sensitive variables among healthcare workers. Two thousand-sixty-five volunteers who received the BNT162b2 vaccine were enrolled in the study and followed up. Demographic, clinical, and social variables (educational level, marital status, occupation, childcare) were evaluated through a self-administered questionnaire. Anti-Spike (S) IgG were measured at 1 month (T1) and at 5 months (T2) after the second vaccine dose. At T1, median anti-S IgG values were 693 [394->800] AU/mL (1 AU = 2.6 BAU). Values > 800 AU/mL (2080 BAU/mL) were directly associated with a previous COVID-19 (p < 0.001) infection and inversely with age (p < 0.001), smoking habit (p < 0.001), and autoimmune diseases (p < 0.001). At T2, a significant decreasing in anti-S IgG values was observed (187 [81-262] AU/mL), with a median decrease of 72 [60-82]%. On multivariate data analysis, a reduction of more than 82% was directly associated with male sex (p < 0.021), age (p < 0.001), smoking (p = 0.038), hypertension (p = 0.042), and, inversely, with previous COVID-19 infection (p < 0.001) and being "cohabiting" (p = 0.005). Our findings suggest that demographic, clinical, and social variables play a role in anti-S IgG values decreasing in long-term follow up and should be considered to find personalized vaccine schedules.

Sex and gender differences in community-acquired pneumonia.

Awareness of the influence of sex ands gender on the natural history of several diseases is increasing. Community-acquired pneumonia (CAP) is the most common acute respiratory disease, and it is associated with both morbidity and mortality across all age groups. Although a role for sex- and gender-based differences in the development and associated complications of CAP has been postulated, there is currently high uncertainty on the actual contribution of these factors in the epidemiology and clinical course of CAP. More evidence has been produced on the topic during the last decades, and sex- and gender-based differences have also been extensively studied in COVID-19 patients since the beginning of the SARS-CoV-2 pandemic. This review aims to provide an extensive outlook of the role of sex and gender in the epidemiology, pathogenesis, treatment, and outcomes of patients with CAP, and on the future research scenarios, with also a specific focus on COVID-19.

The ADA (Age-D-Dimer-Albumin) Score to Predict Thrombosis in SARS-CoV-2.

BACKGROUND: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-related pneumonia is associated with venous and arterial thrombosis. Aim of the study was to find out a new score for predicting thrombosis in patients with SARS-CoV-2. METHODS: We included a cohort of 674 patients affected by SARS-CoV-2, not requiring intensive care units, and followed-up during the hospitalization until discharge. Routine analyses performed at in-hospital admission included also serum albumin and D-dimer while arterial and venous thromboses were the endpoints of the study. RESULTS: During the follow-up, 110 thrombotic events were registered; patients with thrombotic events were older and had lower albumin and higher D-dimer, compared with thrombotic event-free ones. On multivariable logistic regression with step-by-step procedure age, serum albumin, and D-dimer were independently associated with thrombotic events. The linear combination of age, D-dimer, and albumin allowed to build-up the ADA (age-D-dimer-albumin) score, whose area under the curve (AUC) was 0.752 (95% confidence interval [CI], 0.708-0.795). ADA score was internally validated by bootstrap sampling procedure giving an AUC of 0.752 (95% CI: 0.708-0.794). CONCLUSION: Combination of age, D-dimer, and albumin in the ADA score allows identifying SARS-CoV-2 patients at higher risk of thrombotic events.

Platelet and immune signature associated with a rapid response to the BNT162b2 mRNA COVID-19 vaccine.

BACKGROUND: A rapid immune response is critical to ensure effective protection against COVID-19. Platelets are first-line sentinels of the vascular system able to rapidly alert and stimulate the immune system. However, their role in the immune response to vaccines is not known. OBJECTIVE: To identify features of the platelet-immune crosstalk that would provide an early readout of vaccine efficacy in adults who received the mRNA-based COVID-19 vaccine (BNT162b2). METHODS: We prospectively enrolled 11 young healthy volunteers (54% females, median age: 28 years) who received two doses of BNT162b2, 21 days apart, and we studied their platelet and immune response before and after each dose of the vaccine (3 and 10 ± 2 days post-injection), in relation to the kinetics of the humoral response. RESULTS: Participants achieving an effective level of neutralizing antibodies before the second dose of the vaccine (fast responders) had a higher leukocyte count, mounted a rapid cytokine response that incremented further after the second dose, and an elevated platelet turnover that ensured platelet count stability. Their circulating platelets were not more reactive but expressed lower surface levels of the immunoreceptor tyrosine-based inhibitory motif (ITIM)-coupled receptor CD31 (PECAM-1) compared to slow responders, and formed specific platelet-leukocyte aggregates, with B cells, just 3 days after the first dose, and with non-classical monocytes and eosinophils. CONCLUSION: We identified features of the platelet-immune crosstalk that are associated with the development of a rapid humoral response to an mRNA-based vaccine (BNT162b2) and that could be exploited as early biomarkers of vaccine efficacy.

Comparison of Thrombotic Events and Mortality in Patients with Community-Acquired Pneumonia and COVID-19: A Multicenter Observational Study.

BACKGROUND: It is still unclear if patients with community-acquired pneumonia (CAP) and coronavirus disease 2019 (COVID-19) have different rate, typology, and impact of thrombosis on survival. METHODS: In this multicenter observational cohort study, 1,138 patients, hospitalized for CAP (n = 559) or COVID-19 (n = 579) from seven clinical centers in Italy, were included in the study. Consecutive adult patients (age ≥ 18 years) with confirmed COVID-19-related pneumonia, with or without mechanical ventilation, hospitalized from March 1, 2020 to April 30, 2020, were enrolled. COVID-19 was diagnosed based on the World Health Organization interim guidance. Patients were followed-up until discharge or in-hospital death, registering the occurrence of thrombotic events including ischemic/embolic events. RESULTS: During the in-hospital stay, 11.4% of CAP and 15.5% of COVID-19 patients experienced thrombotic events (p = 0.046). In CAP patients all the events were arterial thromboses, while in COVID-19 patients 8.3% were venous and 7.2% arterial thromboses.During the in-hospital follow-up, 3% of CAP patients and 17% of COVID-19 patients died (p < 0.001). The highest mortality rate was found among COVID-19 patients with thrombotic events (47.6 vs. 13.4% in thrombotic-event-free patients; p < 0.001). In CAP, 13.8% of patients experiencing thrombotic events died versus 1.8% of thrombotic event-free ones (p < 0.001). A multivariable Cox-regression analysis confirmed a higher risk of death in COVID-19 patients with thrombotic events (hazard ratio: 2.1; 95% confidence interval: 1.4-3.3; p < 0.001). CONCLUSION: Compared with CAP, COVID-19 is characterized by a higher burden of thrombotic events, different thrombosis typology and higher risk of thrombosis-related in-hospital mortality.

Cutaneous adverse reactions after COVID-19 vaccines in a cohort of 2740 Italian subjects: An observational study.

An in-depth characterization of the incidence, morphology, and onset of COVID-19-vaccines cutaneous adverse reactions is currently lacking. The existing literature on COVID-19 vaccination-related cutaneous adverse reactions largely focused on messenger RNA vaccines and mainly included type 1 hypersensitivity reactions, such as urticaria and angioedema. Other cutaneous manifestations are still poorly characterized and have been classified as delayed hypersensitivity rash. Our prospective observational study on a sample of 2740 subjects who underwent the COVID-19 vaccination aimed at defining the prevalence of cutaneous adverse reactions and at identifying their timing of onset and their correlation with the administered dose. Vaccine-related cutaneous adverse reactions occurred in 50 subjects. Patients were asked to complete a questionnaire on the type of COVID-19 vaccine received, the time of onset of cutaneous reactions, and the dates of administration. Out of 2740 individuals who received the COVID-19 vaccination, 50 were diagnosed with cutaneous adverse reactions to vaccine, after the first dose in 28 patients, after the second in 20, and after both in two. We reported localized injection site erythema in 12 patients and generalized cutaneous reactions in 38 patients. Our study shows that cutaneous adverse reactions to COVID-19 vaccination are not common and most often occur after the first dose, recurring infrequently after the second dose. These reactions are usually easily manageable and, even in severe generalized cases, oral antihistamines and corticosteroids were sufficient for resolution. Therefore, except for immediate hypersensitivity reactions, cutaneous adverse reactions do not represent a contraindication to the completion of the vaccination cycle.

Prevalence of right ventricular dysfunction and impact on all-cause death in hospitalized patients with COVID-19: a systematic review and meta-analysis.

The Coronavirus Disease (COVID-19) pandemic imposed a high burden of morbidity and mortality. In COVID-19, direct lung parenchymal involvement and pulmonary microcirculation dysfunction may entail pulmonary hypertension (PH). PH and direct cardiac injury beget right ventricular dysfunction (RVD) occurrence, which has been frequently reported in COVID-19 patients; however, the prevalence of RVD and its impact on outcomes during COVID-19 are still unclear. This study aims to evaluate the prevalence of RVD and associated outcomes in patients with COVID-19, through a Systematic Review and Meta-Analysis. MEDLINE and EMBASE were systematically searched from inception to 15th July 2021. All studies reporting either the prevalence of RVD in COVID-19 patients or all-cause death according to RVD status were included. The pooled prevalence of RVD and Odds Ratio (OR) for all-cause death according to RVD status were computed and reported. Subgroup analysis and meta-regression were also performed. Among 29 studies (3813 patients) included, pooled prevalence of RVD was 20.4% (95% CI 17.1-24.3%; 95% PI 7.8-43.9%), with a high grade of heterogeneity. No significant differences were found across geographical locations, or according to the risk of bias. Severity of COVID-19 was associated with increased prevalence of RVD at meta-regression. The presence of RVD was found associated with an increased likelihood of all-cause death (OR 3.32, 95% CI 1.94-5.70). RVD was found in 1 out of 5 COVID-19 patients, and was associated with all-cause mortality. RVD may represent one crucial marker for prognostic stratification in COVID-19; further prospective and larger are needed to investigate specific management and therapeutic approach for these patients.

Arterial and venous thrombosis in coronavirus 2019 disease (Covid-19): relationship with mortality.

BACKGROUND: Patients with coronavirus disease 2019 (Covid-19) may experience venous thrombosis while data regarding arterial thrombosis are sparse. METHODS: Prospective multicenter study in 5 hospitals including 373 patients with Covid-19-related pneumonia. Demographic data, laboratory findings including coagulation tests and comorbidities were reported. During the follow-up any arterial or venous thrombotic events and death were registered. RESULTS: Among 373 patients, 75 (20%) had a thrombotic event and 75 (20%) died. Thrombotic events included 41 venous thromboembolism and 34 arterial thrombosis. Age, cardiovascular disease, intensive care unit treatment, white blood cells, D-dimer, albumin and troponin blood levels were associated with thrombotic events. In a multivariable regression logistic model, intensive care unit treatment (Odds Ratio [OR]: 6.0; 95% Confidence Interval [CI] 2.8-12.6; p < 0.001); coronary artery disease (OR: 2.4; 95% CI 1.4-5.0; p = 0.022); and albumin levels (OR: 0.49; 95% CI 0.28-0.87; p = 0.014) were associated with ischemic events. Age, sex, chronic obstructive pulmonary disease, diabetes, heart failure, coronary heart disease, intensive care unit treatment, in-hospital thrombotic events, D-dimer, C-reactive protein, troponin, and albumin levels were associated with mortality. A multivariable Cox regression analysis showed that in-hospital thrombotic events (hazard ratio [HR]: 2.72; 95% CI 1.59-4.65; p < 0.001), age (HR: 1.035; 95% CI 1.014-1.057; p = 0.001), and albumin (HR: 0.447; 95% CI 0.277-0.723; p = 0.001) predicted morality. CONCLUSIONS: Covid-19 patients experience an equipollent rate of venous and arterial thrombotic events, that are associated with poor survival. Early identification and appropriate treatment of Covid-19 patients at risk of thrombosis may improve prognosis.

Low-Grade Endotoxemia and Thrombosis in COVID-19.

INTRODUCTION: Patients with community-acquired pneumonia display enhanced levels of lipopolysaccharides (LPS) compared with controls, suggesting that low-grade endotoxemia may be implicated in vascular disturbances. It is unknown whether this occurs in patients with coronavirus 2019 (COVID-19) and its impact on thrombotic complications. METHODS: We measured serum levels of zonulin, a marker of gut permeability, LPS, and D-dimer in 81 patients with COVID-19 and 81 healthy subjects; the occurrence of thrombotic events in COVID-19 during the intrahospital stay was registered. RESULTS: Serum LPS and zonulin were higher in patients with COVID-19 than in control subjects and, in COVID-19, significantly correlated (R = 0.513; P < 0.001). Among the 81 patients with COVID-19, 11 (14%) experienced thrombotic events in the arterial (n = 5) and venous circulation (n = 6) during a median follow-up of 18 days (interquartile range 11-27 days). A logistic regression analysis showed that LPS (P = 0.024) and D-dimer (P = 0.041) independently predicted thrombotic events. DISCUSSION: The study reports that low-grade endotoxemia is detectable in patients with COVID-19 and is associated with thrombotic events. The coexistence of low-grade endotoxemia with enhanced levels of zonulin may suggest enhanced gut permeability as an underlying mechanism.

Nox2 activation in Covid-19.

Nox2 is responsible for artery dysfunction via production of reactive oxidant species. RNA viruses may activate Nox2, but it is unknown if this occurs in coronavirus 2019(Covid-19). Nox2 activation by soluble Nox2-derived peptide(sNox2-dp) was measured in patients hospitalized for Covid-19 (n = 182) and controls (n = 91). sNox2-dp values were higher in Covid-19 patients versus controls and in severe versus non severe Covid-19. Patients with thrombotic events(n = 35,19%) had higher sNox2-dp than thrombotic event-free ones. A logistic regression analysis showed that sNox2 and coronary heart disease predicted thrombotic events. Oxidative stress by Nox2 activation is associated severe disease and thrombotic events in Covid-19 patients.

Is Albumin Predictor of Mortality in COVID-19?

Coronavirus 2019 (COVID-19) is a pandemic associated with a high risk of mortality. Human serum albumin (HSA) is an acute phase reactant with antioxidant property; however, its behavior and impact on survival in COVID-19 patients have never been studied so far. Among 319 COVID-19 patients followed up for a median of 19 days, 64 died. Compared with survivors, nonsurvivors had more prevalence of intensive care unit (ICU) admission, chronic obstructive pulmonary disease (COPD), heart failure, elevated levels of D-dimer, high-sensitivity C reactive protein (hs-CRP) and troponins, and lower values of albumin. At the Cox regression analysis, albumin (hazard ratio [HR]: 0.38, 95% confidence interval [CI]: 0.23-0.63, p < 0.001) and age (HR: 1.03, 95% CI: 1.01-1.06, p = 0.001) were independently associated with mortality, irrespective of adjustment for gender, ICU admission, heart failure, COPD, and hs-CRP levels. Our observation leads to the hypothesis that HSA analysis may be used to identify patients at higher risk of death in COVID-19 patients.

SARS-CoV-2 and myocardial injury: a role for Nox2?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be complicated by myocardial injury but at-risk patients as well as mechanism of disease are unclear. We gathered data regarding troponin levels in the so far reported SARS-CoV-2 patients and found a large variability in terms of troponin levels, patients with more severe disease, as those treated by ICU, presenting with higher percentage of troponin elevation. However, lack of prospective studies hampers adequate analysis of risk factors of myocardial damage. Previous study demonstrated that Nox2 is up-regulated in pneumonia and closely associated with troponin elevation suggesting Nox2 activation as mechanism eliciting myocardial damage; data in SARS-CoV-2 are still lacking. We hypothesize that SARS-Cov-2 may induce myocardial injury via Nox2-related ROS production and that analysis and eventually targeting Nox2 may be a novel approach to manage SARS-CoV-2.

Hypercoagulation and Antithrombotic Treatment in Coronavirus 2019: A New Challenge.

The novel coronavirus 2019 (COVID-19) is clinically characterized by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is responsible for a high number of patients needing mechanical ventilation or intensive care units treatment and for the elevated mortality risk. A link between COVID-19 and multiorgan failure may be dependent on the fact that most COVID-19 patients are complicated by pneumonia, which is known to be associated with early changes of clotting and platelet activation and artery dysfunction; these changes may implicate in thrombotic-related events such as myocardial infarction and ischemic stroke. Recent data showed that myocardial injury compatible with coronary ischemia may be detectable in SARS-CoV-2 patients and laboratory data exploring clotting system suggest the presence of a hypercoagulation state. Thus, we performed a systematic review of COVID-19 literature reporting measures of clotting activation to assess if changes are detectable in this setting and their relationship with clinical severity. Furthermore, we discussed the biologic plausibility of the thrombotic risk in SARS-CoV-2 and the potential use of an antithrombotic treatment.