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.

Asymptomatic and symptomatic deep venous thrombosis in hospitalized acutely ill medical patients: risk factors and therapeutic implications.

BACKGROUND: Acutely ill medical patients experience deep venous thrombosis (DVT) during the hospitalization, however the time course of DVT is still unclear. OBJECTIVES: To evaluate risk factors in acutely ill hospitalized medical patients for proximal asymptomatic DVT (ADVT) and symptomatic DVT (SDVT) at admission and discharge. PATIENTS/METHODS: In this prospective observational study, consecutive acutely ill medical patients (hospitalized mainly for acute medical disease as infections, neoplasm, anemia, heart failure) underwent compression ultrasonography (CUS) of proximal lower limb veins within 48 h from admission and at discharge to diagnose ADVT and SDVT. Covid-19 patients, anticoagulant therapy, surgical procedures, acute SDVT, and acute pulmonary embolism, were exclusion criteria. Biographical characteristics at hospitalization, D-Dimer (assessed by ELISA)) and DD-improve score. RESULTS: Of 2,100 patients (1002 females, 998 males, age 71 ± 16 years) 58 (2.7%) had proximal ADVT at admission. Logistic regression analysis showed that age, and active cancer were independently associated with ADVT at admission. The median length of hospitalization was 10 days [interquartile range: 6-15]. During the hospital stay, 6 patients (0.3%) with a negative CUS at admission experienced DVT (2 SDVT and 4 ADVT). In the subgroup of patients (n = 1118), in whom D-dimer was measured at admission, D-Dimer and IMPROVE-DD score were associated with ADVT at admission (n = 37) and with all DVT (n = 42) at discharge. ROC curve defined an IMPROVE-DD score of 2.5 as the optimal cut-off for discriminating patients with and without thrombotic events. CONCLUSIONS: We provide evidence of early development of ADVT in unselected acutely ill medical patients suggesting the need of investigating patients by CUS immediately after hospital admission (within 48 h). Advanced age, active cancer, known thrombophilia and increased IMPROVE-DD score may identify patients at risk. The benefit of anticoagulation needs to be investigated in patients with these specific risk factors and negative CUS at admission. TRIAL REGISTRATION: NCT03157843.

Low-grade endotoxemia and NOX2 in patients with coronary microvascular angina.

BACKGROUND: Endothelial dysfunction and oxidative stress were hypothesized to be involved in the pathogenesis of coronary microvascular angina (MVA). NADPH oxidase-2 (NOX2) activation could provoke increased oxidative stress and endothelial dysfunction, but data on MVA have not been provided yet. AIMS: This study aimed to evaluate the interaction among NOX2 activation, serum lipopolysaccharide (LPS) levels, as well as oxidative stress production as potential causes of endothelial dysfunction in MVA patients. METHODS: In this study, we wanted to compare serum levels of soluble NOX2-dp (sNOX2-dp), H2O2 production, hydrogen peroxide breakdown activity (HBA), nitric oxide (NO) bioavailability, endothelin 1 (ET-1), serum zonulin (as intestinal permeability assay), and LPS in 80 consecutive subjects, including 40 MVA patients and 40 controls (CT), matched for age and sex. RESULTS: Compared with CT, MVA patients had significantly higher values of sNOX2-dp, H2O2, ET-1, LPS, and zonulin. Conversely HBA and NO bioavailability were significantly lower in MVA patients. Simple linear regression analysis showed that sNOX2 was associated with serum LPS, serum zonulin, H2O2, and ET-1. Furthermore, an inverse correlation between sNOX2, HBA, and nitric oxide bioavailability was observed. Multiple linear regression analysis showed that LPS and zonulin emerged as the only independent predictive variables associated with sNOX2. CONCLUSIONS: This study provides the first report attesting that patients with MVA have high LPS levels, NOX2 activation, and an imbalance between pro-oxidant and antioxidant systems, in favor of the oxidizing molecules that could be potentially implicated in the endothelial dysfunction and vasoconstriction of this disease.

Chocolate enriched by extra virgin olive oil improves endothelial function and oxidative stress in patients with diabetes.

OBJECTIVE: Endothelial dysfunction and oxidative stress are among the most relevant mechanisms underlying the atherosclerotic process in patients with type 2 diabetes mellitus (T2 DM). Extra virgin olive oil (EVOO) reduces postprandial glycemia with a mechanism counteracting oxidative stress-mediated incretin down-regulation in healthy subjects and in patients with impaired fasting glucose. The aim of this study was to evaluate if the intake of chocolate enriched by EVOO had positive effects on endothelial function and oxidative stress in patients with T2 DM. METHODS: In this study we enrolled and randomly assigned 25 consecutive patients with T2 DM to receive 40 g of EVOO-enriched chocolate or 40 g of control chocolate spread. Participants were assessed at baseline and 2 h after chocolate intake. Endothelial function was assessed by arterial brachial flow-mediated dilation (FMD); oxidative stress was evaluated by the measurement of serum nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-2 (Nox2) levels, nitric oxide availability, and serum hydrogen peroxide breakdown activity (HBA). RESULTS: We observed a significant increase of FMD, nitric oxide (NO) availability, and HBA in the EVOO-enriched chocolate group (P < 0.001). Conversely, soluble Nox2-derived peptide (sNox2-dp) levels significantly decreased (P < 0.001). No significant change was observed in the control chocolate group. To assess the relation of EVOO-enriched chocolate to endothelial function and oxidative stress, a general linear model (GLM) analysis was performed; a significant difference for treatments was found with respect to FMD, NO availability, HBA, and sNox-dp. CONCLUSIONS: Administration of 40 g of EVOO-enriched chocolate is associated with increased endothelial function and reduction of oxidative stress in patients with T2 DM. Future studies are needed to analyze the effect of chronic assumption of EVOO-enriched chocolate on vascular function, oxidative stress, and cardiovascular complications in patients with T2 DM.