Publications

SARS-CoV-2 infection leads to a highly variable clinical evolution, ranging from asymptomatic to severe disease with acute respiratory distress syndrome, requiring intensive care units (ICU) admission. The optimal management of hospitalized patients has become a worldwide concern and identification of immune biomarkers predictive of the clinical outcome for hospitalized patients remains a major challenge. Immunophenotyping and transcriptomic analysis of hospitalized COVID-19 patients at admission allow identifying the two categories of patients. Inflammation, high neutrophil activation, dysfunctional monocytic response and a strongly impaired adaptive immune response was observed in patients who will experience the more severe form of the disease. This observation was validated in an independent cohort of patients. Using in silico analysis on drug signature database, we identify differential therapeutics that specifically correspond to each group of patients. From this signature, we propose a score—the SARS-Score—composed of easily quantifiable biomarkers, to classify hospitalized patients upon arrival to adapt treatment according to their immune profile.

Abstract Introduction The monitoring of unfractionated heparin (UFH) by anti‐factor Xa activity (AXA) is commonly used to ensure effective anticoagulation and prevent bleeding risk. However, in patients previously treated with an anti‐Xa direct oral anticoagulant (DOAC) switching to UFH therapy, there is a risk of interference that may lead to inappropriate anticoagulation. The first objective of this study was to validate DOAC‐Remove to remove DOAC for measuring UFH specific AXA. The second objective was to assess the length of DOAC interference on UFH monitoring and to identify potential predictive factors. Materials and Methods This monocentric retrospective study included all patients admitted from April 2019 to April 2021 previously treated with anti‐Xa DOAC, and for whom an interference on UFH monitoring was suspected. Interference was defined as a difference in the AXA measured before and after using DOAC‐Remove >2.8‐fold standard deviation of the method. Results Removal with DOAC‐Remove was specific of DOAC (apixaban n = 42, rivaroxaban n = 41, UFH n = 20) and sufficient to avoid interference on UFH AXA measurement. The exact interference length was 6.0 days [IQR 3.0–11.0] for apixaban ( n = 26) and 4.5 days [IQR 2.0–5.8] for rivaroxaban ( n = 20). Among the 89 patients sorted based on an interference length ≤ or >3 days, 74 (83.1%) presented an interference greater than 3 days. Correlations were observed with age for apixaban and creatinine for rivaroxaban. Conclusions Our results suggest that DOAC‐Remove could be of high interest in patients receiving UFH previously treated with an anti‐Xa DOAC even if DOAC was stopped for more than 3 days.

As compared with controls, ECFC-ECs from individuals with VTD have higher oxidative stress, proliferation stress, cellular senescence, and low proliferative potential. These findings suggest that patients with a history of VTD are ECFC-ECs dysfunctional that could be associated to permanent risk for new thrombotic events.

TRIAL REGISTRATION: NCT04420468. OBJECTIVES: Severe acute respiratory syndrome coronavirus 2–related multisystem inflammatory syndrome in children is frequently associated with shock; endothelial involvement may be one of the underlying mechanisms. We sought to describe endothelial dysfunction during multisystem inflammatory syndrome in children with shock and then assess the relationship between the degree of endothelial involvement and the severity of shock. DESIGN: Observational study. SETTING: A PICU in a tertiary hospital. PATIENTS: Patients aged under 18 ( n = 28) with severe acute respiratory syndrome coronavirus 2–related multisystem inflammatory syndrome in children and shock, according to the Centers for Disease Control and Prevention criteria. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Correlations between endothelial marker levels and shock severity were assessed using Spearman coefficient. The median (interquartile range) age was 9 years (7.5–11.2 yr). Sixteen children presented with cardiogenic and distributive shock, 10 presented with cardiogenic shock only, and two presented with distributive shock only. The median left ventricular ejection fraction, troponin level, and lactate level were, respectively, 40% (35–45%), 261 ng/mL (131–390 ng/mL), and 3.2 mmol/L (2–4.2 mmol/L). Twenty-five children received inotropes and/or vasopressors; the median Vasoactive and Inotropic Score was 8 (5–28). Plasma levels of angiopoietin-2 (6,426 pg/mL [2,814–11,836 pg/mL]), sE-selectin (130,405 pg/mL [92,987–192,499 pg/mL]), von Willebrand factor antigen (344% [288–378%]), and the angiopoietin-2/angiopoietin-1 ratio (1.111 [0.472–1.524]) were elevated and significantly correlated with the Vasoactive and Inotropic Score ( r = 0.45, p = 0.016; r = 0.53, p = 0.04; r = 0.46, p = 0.013; and r = 0.46, p = 0.012, respectively). CONCLUSIONS: Endothelial dysfunction is associated with severe acute respiratory syndrome coronavirus 2–related multisystem inflammatory syndrome in children with shock and may constitute one of the underlying mechanisms.

Summary Endothelial colony-forming cells (ECFCs) are progenitor cells committed to endothelial lineages and have robust vasculogenic properties. Mesenchymal stem cells (MSCs) have been described to support ECFC-mediated angiogenic processes in various matrices. However, MSC-ECFC interactions in hind limb ischemia (HLI) are largely unknown. Here we examined whether co-administration of ECFCs and MSCs bolsters vasculogenic activity in nude mice with HLI. In addition, as we have previously shown that endoglin is a key adhesion molecule, we evaluated its involvement in ECFC/MSC interaction. Foot perfusion increased on day 7 after ECFC injection and was even better at 14 days. Co-administration of MSCs significantly increased vessel density and foot perfusion on day 7 but the differences were no longer significant at day 14. Analysis of mouse and human CD31, and in situ hybridization of the human ALU sequence, showed enhanced capillary density in ECFC+MSC mice. When ECFCs were silenced for endoglin, coinjection with MSCs led to lower vessel density and foot perfusion at both 7 and 14 days (p<0.001). Endoglin silencing in ECFCs did not affect MSC differentiation into perivascular cells or other mesenchymal lineages. Endoglin silencing markedly inhibited ECFC adhesion to MSCs. Thus, MSCs, when combined with ECFCs, accelerate muscle recovery in a mouse model of hind limb ischemia, through an endoglindependent mechanism. Supplementary Material to this article is available online at www.thrombosis-online.com.