Project description:ObjectivesDuring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, dramatic endothelial cell damage with pulmonary microvascular thrombosis have been was hypothesized to occur. The aim was to assess whether pulmonary vascular thrombosis (PVT) is due to recurrent thromboembolism from peripheral deep vein thrombosis or to local inflammatory endothelial damage, with a superimposed thrombotic late complication.DesignObservational study.SettingMedical and intensive care unit wards of a teaching hospital.ParticipantsThe authors report a subset of patients included in a prospective institutional study (CovidBiob study) with clinical suspicion of pulmonary vascular thromboembolism.InterventionsComputed tomography pulmonary angiography and evaluation of laboratory markers and coagulation profile.Measurements and main resultsTwenty-eight of 55 (50.9%) patients showed PVT, with a median time interval from symptom onset of 17.5 days. Simultaneous multiple PVTs were identified in 22 patients, with bilateral involvement in 16, mostly affecting segmental/subsegmental pulmonary artery branches (67.8% and 96.4%). Patients with PVT had significantly higher ground glass opacity areas (31.7% [22.9-41] v 17.8% [10.8-22.1], p < 0.001) compared with those without PVT. Remarkably, in all 28 patients, ground glass opacities areas and PVT had an almost perfect spatial overlap. D-dimer level at hospital admission was predictive of PVT.ConclusionsThe findings identified a specific radiologic pattern of coronavirus disease 2019 (COVID-19) pneumonia with a unique spatial distribution of PVT overlapping areas of ground-glass opacities. These findings supported the hypothesis of a pathogenetic relationship between COVID-19 lung inflammation and PVT and challenged the previous definition of pulmonary embolism associated with COVID-19 pneumonia.
Project description:AimsSeveral reports indicate that diabetes determines an increased mortality risk in patients with coronavirus disease 19 (COVID-19) and a good glycaemic control appears to be associated with more favourable outcomes. Evidence also supports that COVID-19 pneumonia only accounts for a part of COVID-19 related deaths. This disease is indeed characterised by abnormal inflammatory response and vascular dysfunction, leading to the involvement and failure of different systems, including severe acute respiratory distress syndrome, coagulopathy, myocardial damage and renal failure. Inflammation and vascular dysfunction are also well-known features of hyperglycemia and diabetes, making up the ground for a detrimental synergistic combination that could explain the increased mortality observed in hyperglycaemic patients.Materials and methodsIn this work, we conduct a narrative review on this intriguing connection. Together with this, we also present the clinical characteristics, outcomes, laboratory and histopathological findings related to this topic of a cohort of nearly 1000 subjects with COVID-19 admitted to a third-level Hospital in Milan.ResultsWe found an increased mortality in subjects with COVID-19 and diabetes, together with an altered inflammatory profile.ConclusionsThis may support the hypothesis that diabetes and COVID-19 meet at the crossroads of inflammation and vascular dysfunction. (ClinicalTrials.gov NCT04463849 and NCT04382794).
Project description:Rationale: Infection with the SARS-CoV2 virus is associated with elevated neutrophil counts. Evidence of neutrophil dysfunction in COVID-19 is based on transcriptomics or single functional assays. Cell functions are interwoven pathways, and understanding the effect across the spectrum of neutrophil function may identify therapeutic targets. Objectives: Examine neutrophil phenotype and function in 41 hospitalised, non-ICU COVID-19 patients versus 23 age-matched controls (AMC) and 26 community acquired pneumonia patients (CAP). Methods: Isolated neutrophils underwent ex vivo analyses for migration, bacterial phagocytosis, ROS generation, NETosis and receptor expression. Circulating DNAse 1 activity, levels of cfDNA, MPO, VEGF, IL-6 and sTNFRI were measured and correlated to clinical outcome. Serial sampling on day three to five post hospitalization were also measured. The effect of ex vivo PI3K inhibition was measured in a further cohort of 18 COVID-19 patients. Results: Compared to AMC and CAP, COVID-19 neutrophils demonstrated elevated transmigration (p = 0.0397) and NETosis (p = 0.0332), and impaired phagocytosis (p = 0.0036) associated with impaired ROS generation (p < 0.0001). The percentage of CD54+ neutrophils (p < 0.001) was significantly increased, while surface expression of CD11b (p = 0.0014) and PD-L1 (p = 0.006) were significantly decreased in COVID-19. COVID-19 and CAP patients showed increased systemic markers of NETosis including increased cfDNA (p = 0.0396) and impaired DNAse activity (p < 0.0001). The ex vivo inhibition of PI3K γ and δ reduced NET release by COVID-19 neutrophils (p = 0.0129). Conclusions: COVID-19 is associated with neutrophil dysfunction across all main effector functions, with altered phenotype, elevated migration and NETosis, and impaired antimicrobial responses. These changes highlight that targeting neutrophil function may help modulate COVID-19 severity.
Project description:BackgroundProgressive respiratory failure is the primary cause of death in the coronavirus disease 2019 (Covid-19) pandemic. Despite widespread interest in the pathophysiology of the disease, relatively little is known about the associated morphologic and molecular changes in the peripheral lung of patients who die from Covid-19.MethodsWe examined 7 lungs obtained during autopsy from patients who died from Covid-19 and compared them with 7 lungs obtained during autopsy from patients who died from acute respiratory distress syndrome (ARDS) secondary to influenza A(H1N1) infection and 10 age-matched, uninfected control lungs. The lungs were studied with the use of seven-color immunohistochemical analysis, micro-computed tomographic imaging, scanning electron microscopy, corrosion casting, and direct multiplexed measurement of gene expression.ResultsIn patients who died from Covid-19-associated or influenza-associated respiratory failure, the histologic pattern in the peripheral lung was diffuse alveolar damage with perivascular T-cell infiltration. The lungs from patients with Covid-19 also showed distinctive vascular features, consisting of severe endothelial injury associated with the presence of intracellular virus and disrupted cell membranes. Histologic analysis of pulmonary vessels in patients with Covid-19 showed widespread thrombosis with microangiopathy. Alveolar capillary microthrombi were 9 times as prevalent in patients with Covid-19 as in patients with influenza (P<0.001). In lungs from patients with Covid-19, the amount of new vessel growth - predominantly through a mechanism of intussusceptive angiogenesis - was 2.7 times as high as that in the lungs from patients with influenza (P<0.001).ConclusionsIn our small series, vascular angiogenesis distinguished the pulmonary pathobiology of Covid-19 from that of equally severe influenza virus infection. The universality and clinical implications of our observations require further research to define. (Funded by the National Institutes of Health and others.).
Project description:Several studies have described unusually high incidence of vascular thrombosis in coronavirus disease-2019 (COVID-19) patients. Pathogenesis of the vascular thrombosis in COVID-19 is least understood for now and presents a challenge to the treating physicians. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative pathogen for COVID-19, has been shown to bind to angiotensin converting enzyme 2 (ACE2) protein in human epithelial cells which facilitates its entry in the organ and mediate tissue specific pathogenesis. For ACE2 mediated cell entry of the SARS-CoV-2, co-expression of one more protein-Transmembrane protease serine 2 (TMPRSS2) is essential. Existing studies suggested significant expression of ACE2 and TMPRSS2 in human vascular endothelium. Vascular endothelial dysfunction can potentially activate coagulation cascade eventually resulting in thrombosis. ACE2 has proven role in the maintenance of endothelial integrity inside the vessels. Existing in situ evidence for SARS-CoV-1 (the causative agent for SARS pandemic of 2002, which shared ACE2 as cell entry receptor) suggested that virus binding can downregulate ACE2, thus can induce endothelial dysfunction. Recently, in situ evidence has been presented that SARS-CoV-2 can infect cells in engineered human vascular endothelium, which can be effectively blocked by using clinical-grade recombinant human ACE2. Based on the circumstantial evidence present in the literature, we propose a SARS-CoV-2 cell entry receptor ACE2 based mechanism for vascular thrombosis in COVID-19 patients.
Project description:Current knowledge regarding mechanisms underlying cardiovascular complications in patients with COVID-19 is limited and urgently needed. We shed light on a previously unrecognized mechanism and unravel a key role of red blood cells, driving vascular dysfunction in patients with COVID-19 infection. We establish the presence of profound and persistent endothelial dysfunction in vivo in patients with COVID-19. Mechanistically, we show that targeting reactive oxygen species or arginase 1 improves vascular dysfunction mediated by red blood cells. These translational observations hold promise that restoring the redox balance in red blood cells might alleviate the clinical complications of COVID-19-associated vascular dysfunction.
Project description:Background and aimsHigh levels of lipoprotein(a) could worsen the outcome of COVID-19 due to prothrombotic and proinflammatory properties of lipoprotein(a). We tested the hypotheses that during COVID-19 hospitalization i) increased thrombotic activity and inflammation are associated with lipoprotein(a) levels, and ii) lipoprotein(a) levels are associated with rate of hospital death and discharge.MethodsWe studied 211 patients admitted to Copenhagen University Hospital in 2020 with COVID-19, that is, prior to any vaccination. Thrombotic activity was marked by elevated D-dimer while inflammation was marked by elevated interleukin-6, C-reactive protein, and procalcitonin. Patients were followed until death (N = 36) or discharge (N = 175).ResultsA 2-fold higher D-dimer was associated with 14% (95%CI: 8.1-20%) higher lipoprotein(a). Conversely, 2-fold higher interleukin-6, C-reactive protein, and procalcitonin were associated with respectively 4.3% (0.62-7.8%), 5.7% (0.15-5.2%), and 8.7% (5.2-12%) lower lipoprotein(a). For hospital death, the multivariable adjusted hazard ratio per 2-fold higher lipoprotein(a) was 1.26 (95%CI:0.91-1.73). Corresponding hazard ratios per 2-fold higher biomarker were 0.93 (0.75-1.16) for D-dimer, 1.42 (1.17-1.73) for interleukin-6, 1.44 (0.95-2.17) for C-reactive protein, and 1.44 (1.20-1.73) for procalcitonin. For hospital discharge, the multivariable adjusted hazard ratio per 2-fold higher lipoprotein(a) was 0.91 (95%CI:0.79-1.06). Corresponding hazard ratios per 2-fold higher biomarker were 0.86 (0.75-0.98) for D-dimer, 0.84 (0.76-0.92) for interleukin-6, 0.80 (0.71-0.90) for C-reactive protein, and 0.76 (0.67-0.88) for procalcitonin.ConclusionsIn COVID-19 patients, thrombotic activity marked by elevated D-dimer was associated with higher lipoprotein(a) while elevated inflammatory biomarkers of interleukin-6, C-reactive protein, and procalcitonin were associated with lower lipoprotein(a); however, elevated lipoprotein(a) was not associated with rate of hospital death or discharge.
Project description:Patients with psoriasis have systemic and vascular inflammation and are at increased risk for myocardial infarction, stroke, and cardiovascular death. However, the underlying mechanism(s) mediating the link between psoriasis and vascular disease is incompletely defined. This study sought to determine whether chronic skin-specific inflammation has the capacity to promote vascular inflammation and thrombosis. Using the KC-Tie2 doxycycline-repressible (Dox-off) murine model of psoriasiform skin disease, spontaneous aortic root inflammation was observed in 33% of KC-Tie2 compared with 0% of control mice by 12 months of age (P=0.04) and was characterized by the accumulation of macrophages, T lymphocytes, and B lymphocytes, as well as by reduced collagen content and increased elastin breaks. Importantly, aortic inflammation was preceded by increases in serum tumor necrosis factor-?, IL-17A, vascular endothelial growth factor, IL-12, monocyte chemotactic protein-1, and S100A8/A9, as well as splenic and circulating CD11b(+)Ly-6C(hi) pro-inflammatory monocytes. Doxycycline treatment of old mice with severe skin disease eliminated skin inflammation and the presence of aortic root lesion in 1-year-old KC-Tie2 animals. Given the bidirectional link between inflammation and thrombosis, arterial thrombosis was assessed in KC-Tie2 and control mice; mean time to occlusive thrombus formation was shortened by 64% (P=0.002) in KC-Tie2 animals; and doxycycline treatment returned thrombosis clotting times to that of control mice (P=0.69). These findings demonstrate that sustained skin-specific inflammation promotes aortic root inflammation and thrombosis and suggest that aggressive treatment of skin inflammation may attenuate pro-inflammatory and pro-thrombotic pathways that produce cardiovascular disease in psoriasis patients.
Project description:The high incidence of thrombotic events suggests a possible role of the contact system pathway in COVID-19 pathology. In this study, we determined the altered levels of factor XII (FXII) and its activation products in critically ill patients with COVID-19 in comparison with patients with severe acute respiratory distress syndrome related to the influenza virus (acute respiratory distress syndrome [ARDS]-influenza). Compatible with those data, we found rapid consumption of FXII in COVID-19 but not in ARDS-influenza plasma. Interestingly, the lag phase in fibrin formation, triggered by the FXII activator kaolin, was not prolonged in COVID-19, as opposed to that in ARDS-influenza. Confocal and electron microscopy showed that increased FXII activation rate, in conjunction with elevated fibrinogen levels, triggered formation of fibrinolysis-resistant, compact clots with thin fibers and small pores in COVID-19. Accordingly, clot lysis was markedly impaired in COVID-19 as opposed to that in ARDS-influenza. Dysregulated fibrinolytic system, as evidenced by elevated levels of thrombin-activatable fibrinolysis inhibitor, tissue-plasminogen activator, and plasminogen activator inhibitor-1 in COVID-19 potentiated this effect. Analysis of lung tissue sections revealed widespread extra- and intravascular compact fibrin deposits in patients with COVID-19. A compact fibrin network structure and dysregulated fibrinolysis may collectively contribute to a high incidence of thrombotic events in COVID-19.