Nicolas Gendron

Hôpital Européen Georges-Pompidou (Hôpitaux Universitaires Paris-Ouest) · Service d’Hématologie

Background Coronavirus disease‐2019 (COVID‐19) has been associated with cardiovascular complications and coagulation disorders. Objectives To explore the coagulopathy and endothelial dysfunction in COVID‐19 patients. Methods Study analyzed clinical and biological profiles of patients with suspected COVID‐19 infection at admission, including hemos...

Objective: The study's aim was to analyze the capacity of human valve interstitial cells (VICs) to participate in aortic valve angiogenesis. Approach and Results: VICs were isolated from human aortic valves obtained after surgery for calcific aortic valve disease and from normal aortic valves unsuitable for grafting (control VICs). We examined VIC...

Background: Idarucizumab has been included in guidelines for the management of bleeding or surgical procedure in dabigatran-treated patients without need for biological monitoring. The aim of the study was to assess the prognostic value of dabigatran plasma level before reversal to test the hemostatic efficacy of idarucizumab. The secondary objecti...

Introduction: Antiphospholipid antibodies (APA) clinical relevance in COVID-19 is controversial. We aimed to investigate the prevalence and prognostic value of conventional and non-conventional APA in COVID-19 patients. Methods: This study was a multi-centric, prospective observational French cohort of patients hospitalized for COVID-19 suspicio...

Background Severe COVID-19 is associated with a high circulating level of calprotectin, the S100A8/S100A9 alarmin heterodimer. Baseline calprotectin amount measured in peripheral blood at diagnosis correlates with disease severity. The optimal use of this biomarker along COVID-19 course remains to be delineated. Methods We focused on patients with...

D‐dimer is a fragment of crosslinked fibrin resulting from plasmin cleavage of fibrin clots and hence an indirect biomarker of the hemostatic system activation. Early in the coronavirus disease 2019 (COVID‐19) pandemic, several studies described coagulation disorders in affected patients, including high D‐dimer levels. Consequently, D‐dimer has bee...

La maladie thromboembolique veineuse (MTEV) est une maladie multifactorielle résultant de l’interaction entre des facteurs de risque environnementaux, cliniques et biologiques. La thrombophilie biologique correspond à la présence d’un facteur de risque biologique acquis ou constitutionnel prédisposant à la maladie thromboembolique veineuse (MTEV)....

Les agents antiplaquettaires et les anticoagulants sont un pilier du traitement et de la prévention secondaire des évènements thrombotiques. Cependant, malgré les progrès obtenus au cours des 10 dernières années dans le développement des thérapeutiques antithrombotiques, un défi fondamental reste encore de minimiser leur effet secondaire principal...

Background Carmat bioprosthetic total artificial heart (Aeson; A-TAH) is a pulsatile and autoregulated device. The aim of this study is to evaluate level of hemolysis potential acquired von Willebrand syndrome after A-TAH implantation. Methods We examined the presence of hemolysis and acquired von Willebrand syndrome in adult patients receiving A-...

Introduction: D-dimer measurement is a safe tool to exclude pulmonary embolism (PE) but its specificity decreases in COVID-19. Our aim was to derive a new algorithm with specific D-dimer threshold in COVID-19 patients. Methods: We conducted a French multicenter, retrospective cohort study among 774 COVID-19 patients with suspected PE. D-dimer th...

Although women have lower age-standardized cardiovascular disease incidence, prevalence, and death-related rates than men, there are also reports indicating that women with cardiovascular disease receive less care, fewer investigations, and have poorer outcomes after a coronary event. The aims of this study were to compare the characteristics of me...

Severe inherited thrombophilia includes rare deficiencies of natural anticoagulants (antithrombin and proteins C and S) and homozygous or combined factor V Leiden and FII G20210A variants. They are associated with a high thrombosis risk and can impact the duration of anticoagulation therapy for patients with a venous thromboembolism (VTE) event. Th...

Introduction La morbi-mortalité cardiovasculaire est un problème majeur chez les patients BPCO et dont l’évènement clé est l’apparition d’une dysfonction endothéliale. Les « Endothelial Colony-Forming Cells » (ECFCs) sont des cellules souches/progénitrices endothéliales qui contribuent à la vasculogénèse physiologique in vivo, et leur défaut de mob...

For more than 10 years, direct oral anticoagulants (DOACs) have been increasingly prescribed for the prevention and treatment of thrombotic events. However, their use in immunothrombotic disorders, namely heparin-induced thrombocytopenia (HIT) and antiphospholipid syndrome (APS), is still under investigation. The prothrombotic state resulting from...

Background Microvascular, arterial and venous thrombotic events have been largely described during severe coronavirus disease 19 (COVID-19). However, mechanisms underlying hemostasis dysregulation remain unclear. Methods We explored two independent cross-sectional cohorts to identify soluble markers and gene-expression signatures that discriminate...

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is presenting as a systemic disease associated with vascular inflammation and endothelial injury. Severe forms of SARS-CoV-2 infection induce acute respiratory distress syndrome (ARDS) and there is still an ongoing debate on whether COVID-19 A...

Background: SARS-CoV-2 uses Angiotensin-Converting Enzyme 2 as a viral gateway to the cell and could interact with the renin-angiotensin-aldosterone system. Other studies have shown kalemia abnormalities in patients with severe forms of coronavirus disease 2019. Our goal was to assess the prognosis value of kalemia within ten days of symptom offset...

Ischemic vascular disease is a major cause of mortality and morbidity worldwide, and regeneration of blood vessels in perfusion‐deficient tissues is a worthwhile therapeutic goal. The idea of delivering endothelial stem/progenitor cells to repair damaged vasculature, reperfuse hypoxic tissue, prevent cell death, and consequently diminish tissue inf...

Background: Microthrombosis and large-vessel thrombosis are the main triggers of COVID-19 worsening. The optimal anticoagulant regimen in COVID-19 patients hospitalized in medical wards remains unknown. Objectives: To evaluate the effects of intermediate-dose vs. standard-dose prophylactic anticoagulation (AC) among patients with COVID-19 hospitali...

The Aeson® total artificial heart (A-TAH) has been developed as a total heart replacement for patients at risk of death from biventricular failure. We previously described endothelialization of the hybrid membrane inside A-TAH probably at the origin of acquired hemocompatibility. We aimed to quantify vasculogenic stem cells in peripheral blood of p...

Background: The outbreak of chilblain-like lesions (CLL) during the COVID-19 pandemic has been reported extensively, potentially related to SARS-CoV-2 infection, yet its underlying pathophysiology is unclear. Objectives: To study skin and blood endothelial and immune system activation in CLL in comparison with healthy controls and seasonal chilb...

Background: The impact of estrogen and testosterone on atherosclerotic cardiovascular disease is well known but the role of gonadotropins: follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL) in some extent remains less studied. Objectives: To explore the angiogenic potential of gonadotropins on endothelial colony-fo...

Laboratory confirmation of heparin-induced thrombocytopenia (HIT) is of crucial importance and remains challenging and relies on platelet functional assays highlighting the presence of heparin-dependent platelet-activating antibodies in patient serum or plasma. Platelet functional assays using washed platelets include the 14C-serotonin release assa...

The Aeson® total artificial heart (A-TAH) has been developed as a total heart replacement for patients at risk of death from biventricular failure. We previously described endothelialization of the hybrid membrane inside A-TAH probably at the origin of acquired hemocompatibility. We aimed to quantify vasculogenic stem cells in peripheral blood of p...

Objective: Coronavirus disease 19 is a well-established cause of rare arterial thrombosis. Nevertheless, the exact mechanism of arterial thrombosis remains to be elucidated. We herein report the case of a large floating thrombus of the aortic arch, its surgical management and histological analysis. Case: A 65-year-old patient presented to the emerg...

Background: Heparin-induced thrombocytopenia (HIT) is a prothrombotic life-threatening disorder caused by an adverse reaction to heparin exposure. In this context, it is imperative to stop heparin immediately and to replace it by a non-heparin anticoagulant therapy. Despite their advantages, the use of direct oral anticoagulants (DOACs) is only eme...

Background Coronavirus disease 2019 (COVID-19) is a respiratory disease associated with endotheliitis and microthrombosis.Objectives To correlate endothelial dysfunction to in-hospital mortality in a bi-centric cohort of COVID-19 adult patients.Methods Consecutive ambulatory and hospitalized patients with laboratory-confirmed COVID-19 were enrolled...

We report a case of a 62‐year‐old man who developed cerebral venous sinus thrombosis with subarachnoid hemorrhage and concomitant thrombocytopenia, which occurred 13 days after ChAdOx1 nCov‐19 injection. The patient died in the intensive care unit after heparin infusion and platelet transfusion. The key clinical purpose of this case report is to be...

Background Microthrombosis is a hallmark of COVID-19. We previously described von willebrand factor (VWF) and their high molecular weight multimers (HMWMs) as potential trigger of microthrombosis.Objectives Investigate VWF activity with collagen-binding assay and ADAMTS13 in COVID-19.Methods and resultsOur study enrolled 77 hospitalized COVID-19 pa...

Endothelial colony-forming cells (ECFCs) are human vasculogenic cells described as potential cell therapy product and good candidates for being a vascular liquid biopsy. Since interleukin-8 (IL-8) is a main actor in senescence, its ability to interact with ECFCs has been explored. However, expression of CXCR1 and CXCR2, the two cellular receptors f...

Endothelial progenitor cells (EPCs) are involved in vasculogenesis and cardiovascular diseases. However, the phenotype of circulating EPCs remains elusive but they are more often described as CD34⁺KDR⁺. The aim of the study was to extensively characterize circulating potential vasculogenic stem cell candidates in two populations of patients with ca...

Background Coronavirus disease 2019 (COVID‐19) is a respiratory disease associated with vascular inflammation and endothelial injury. Objectives Correlate circulating angiogenic markers VEGF‐A, PlGF and FGF‐2 to in‐hospital mortality in COVID‐19 adult patients. Methods Consecutive ambulatory and hospitalized patients with COVID‐19 infection were...

Background: Coronavirus disease 2019 (COVID-19) has been associated with coagulation disorders, in particular high concentrations of D-dimers, and increased frequency of venous thromboembolism. Aim: To explore the association between D-dimers at admission and in-hospital mortality in patients hospitalized for COVID-19, with or without symptomatic v...

Background COVID‐19 is a respiratory disease associated to thrombotic outcomes with coagulation and endothelial disorders. Based on that, several anticoagulation (AC) guidelines have been proposed. We aimed to identify if AC therapy modifies the risk of developing severe COVID‐19. Methods and Results COVID‐19 patients initially admitted in medical...

Introduction Coronavirus disease 2019 (COVID-19) has been associated with cardiovascular complications and coagulation disorders. Previous studies reported pulmonary embolism (PE) in severe COVID-19 patients. Aim of the study was to estimate the prevalence of symptomatic PE in COVID-19 patients and to identify the clinical, radiological or biologic...

Rationale: COVID-19 ARDS could differ from typical forms of the syndrome. Objective: Pulmonary microvascular injury and thrombosis are increasingly reported as constitutive features of COVID-19 respiratory failure. Our aim was to study pulmonary mechanics and gas exchanges in COVID-2019 ARDS patients studied early after initiating protective inv...

Introduction Au cours de l’épidémie de COVID-19, de nombreux cas de pseudo-engelures ont été rapportées mais le lien entre ces lésions et l’infection virale n’est pas établi. Le but de cette étude était de caractériser la clinique, la biologie, l’histologie et l’activation endothéliale de ces lésions. Matériel et méthodes Tous les patients adressé...

Background: Coronavirus disease 2019 (COVID-19) has been associated with cardiovascular complications and coagulation disorders. Objectives: To explore clinical and biological parameters of COVID-19 patients with hospitalization criteria that could predict referral to intensive care unit (ICU). Methods: Analyzing the clinical and biological profile...

Background: Microvascular thrombosis, as well as arterial and venous thrombotic events, have been largely described during severe Coronavirus disease 19 (COVID-19). Therapeutic anticoagulation has been proposed in critical patients, however mechanisms underlying hemostasis dysregulation remain unclear. Methods: We explored two independent cross-sec...

Background Coronavirus disease-2019 (COVID-19), a respiratory disease has been associated with ischemic complications, coagulation disorders, and an endotheliitis.Objectives To explore endothelial damage and activation-related biomarkers in COVID-19 patients with criteria of hospitalization for referral to intensive care unit (ICU) and/or respirato...

Idiopathic pulmonary fibrosis (IPF) is a severe, progressive and irreversible lung disease constantly associated with a major vascular remodeling process. Endothelial colony-forming cells (ECFCs) are human vasculogenic cells proposed as a cell therapy product or liquid biopsy in vascular disorders. Since the link between IPF and thrombosis has been...

Background: Coronavirus disease 2019 (COVID-19) has been associated with coagulation disorders, in particular high levels of D-dimers, and increased frequency of venous thromboembolism (VTE). We explore the association between D-dimers at admission and in-hospital mortality in hospitalized COVID-19 patients with or without symptomatic VTE. Methods:...

Pulsatile Carmat bioprosthetic total artificial heart (C-TAH) is designed to be implanted in patients with biventricular end-stage heart failure. Since flow variation might contribute to endothelial dysfunction, we explored circulating endothelial biomarkers after C-TAH implantation in seven patients and compared the manual and autoregulated mode....

Valproic acid (VPA), a histone deacetylase (HDAC) inhibitor is a widely used anticonvulsant drug. VPA is also under clinical evaluation to be employed in anticancer therapy, as an antithrombotic agent or a molecule to be used in the stem cells expansion protocols. Since endothelial colony forming cells (ECFC) has been identified as the human postna...

Résumé Les anticoagulants oraux directs, anti-IIa ou anti-Xa, sont largement utilisés dans le traitement et la prévention de la maladie thromboembolique veineuse ainsi que dans la fibrillation atriale non valvulaire. Ils sont caractérisés par une action rapide, prévisible et un intervalle thérapeutique large. Néanmoins, des interactions médicamente...

The Carmat bioprosthetic total artificial heart (C-TAH) is a biventricular pump developed to minimize drawbacks of current mechanical assist devices and improve quality of life during support. This study aims to evaluate the safety of the hybrid membrane, which plays a pivotal role in this artificial heart. We investigated in particular its blood-c...

Although bone marrow aspiration (BMA) is still considered a painful procedure, pain level remains poorly documented. We therefore conducted a prospective study intended to evaluate pain level in adult patients undergoing BMA at the sternal or iliac crest site to identify factors associated with pain. We enrolled a total of 448 patients who underwen...

Stem cells at the origin of endothelial progenitor cells and in particular endothelial colony forming cells (ECFCs) subtype have been largely supposed to be positive for the CD133 antigen, even though no clear correlation has been established between its expression and function in ECFCs. We postulated that CD133 in ECFCs might be expressed intracel...

Disseminated toxoplasmosis is infrequent after kidney transplant transmission but life threatening due to a lack of diagnostic suspicion as well as specific chemoprophylaxis recommendations. Solid organ transplantation has resulted in few cases of disseminated toxoplasmosis presenting with associated hemophagocytic syndrome. Herein, we report, with...

Immunoglobulin light chains are called free when they are not linked with heavy chains to form a whole immunoglobulin. Quantification of free light chains is a part of the French national authority for health guidelines for diagnostic and follow-up of light chain, oligo or non-secretory myeloma and AL amyloidosis. Most recently, the World health or...

Idarucizumab is a humanized antigen binding fragment (Fab) of a recombinant anti-dabigatran monoclonal antibody (IgG1-kappa) that allows rapid and sustained reversal of dabigatran-induced anticoagulation in case of bleeding or urgent surgery. Herein, we report a very unusual case of dabigatran reversal by idarucizumab in a 79-year-old woman with ac...

Introduction Idiopathic pulmonary fibrosis (IPF) is a devastating disease characterized by obliteration of alveolar architecture, resulting in declining lung function and ultimately death. Pathogenic mechanisms involve a concomitant accumulation of scar tissue together with myofibroblasts activation and a strong abnormal vascular remodeling. Endoth...