[Human immunodeficiency virus and venous thromboembolism: Role of direct oral anticoagulants]. / Modalités du traitement de la maladie veineuse thromboembolique du patient VIH par les anticoagulants oraux directs.

Nowadays, thanks to highly active antiretroviral therapy (HAART), human immunodeficiency virus (HIV) infection is transforming into a chronic disease. The life expectancy of people living with HIV (PWH) has increased, as well as their risk of developing several co-morbidities, in particular cardiovascular diseases. In addition, the incidence of venous thromboembolism (VTE) is increased in PWH with a 2 to 10 times higher incidence when compared to the general population. Over the last decade, direct oral anticoagulants (DOACs) have been widely used in the treatment and prevention of VTE and non-valvular atrial fibrillation. DOACs are characterized by a rapid onset of activity, a predictable response and a relatively wide therapeutic window. Nevertheless, drug interactions exist between HAART and DOACs, exposing PWH to a theoretically increased bleeding or thrombotic risk. DOACs are substrates of the transport protein P-glycoprotein and/or of isoforms of cytochromes P450 pathway, which can be affected by some antiretroviral drugs. Limited guidelines are available to assist physicians with the complexity of those drug-drug interactions. The aim of this paper is to provide an updated review on the evidence of the high risk of VTE in PWH and the place of DOAC therapy in this population.

Type I interferon response and vascular alteration in chilblain-like lesions during the COVID-19 outbreak.

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 chilblains (SC), defined as cold-induced sporadic chilblains occurring during 2015 and 2019 with exclusion of chilblain lupus. METHODS: This observational study was conducted during 9-16 April 2020 at Saint-Louis Hospital, Paris, France. All patients referred with CLL seen during this period of the COVID-19 pandemic were included in this study. We excluded patients with a history of chilblains or chilblain lupus. Fifty patients were included. RESULTS: Histological patterns were similar and transcriptomic signatures overlapped in both the CLL and SC groups, with type I interferon polarization and a cytotoxic-natural killer gene signature. CLL were characterized by higher IgA tissue deposition and more significant transcriptomic activation of complement and angiogenesis factors compared with SC. We observed in CLL a systemic immune response associated with IgA antineutrophil cytoplasmic antibodies in 73% of patients, and elevated type I interferon blood signature in comparison with healthy controls. Finally, using blood biomarkers related to endothelial dysfunction and activation, and to angiogenesis or endothelial progenitor cell mobilization, we confirmed endothelial dysfunction in CLL. CONCLUSIONS: Our findings support an activation loop in the skin in CLL associated with endothelial alteration and immune infiltration of cytotoxic and type I IFN-polarized cells leading to clinical manifestations.

[Use of antiplatelet therapy and direct oral anticoagulants in candidates for renal transplantation: The French guidelines from the CTAFU]. / Recommandations françaises du Comité de transplantation de l'association française d'urologie (CTAFU) : agents antiplaquettaires et anticoagulants oraux directs en transplantation rénale.

OBJECTIVE: To define guidelines for the use of antiplatelet therapy (AT) and direct oral anticoagulants (DOAC) in candidates for kidney allotransplantation. METHOD: A review of the medical literature following a systematic approach was conducted by the CTAFU to report the use of AT and DOAC before major surgery and in the setting of advanced chronic kidney disease, defining their managment prior to kidney transplantation with the corresponding level of evidence. RESULTS: DOAC are not recommended in patients under dialysis. Aspirin therapy, but not anti-P2Y12 and DOAC, may be maintained during renal transplantation. Anti-P2Y12 and DOAC should not be use in patients awaiting a kidney transplant, except when a living donor is scheduled, therefore authorizing treatment interruption in optimal conditions. Further data regarding DOAC reversion and monitoring may improve their use in this setting. Global level of evidence is weak. CONCLUSION: These French recommendations should contribute to improve surgical management of kidney transplant candidates exposed to AT or DOA.

Respiratory mechanics and gas exchanges in the early course of COVID-19 ARDS: a hypothesis-generating study.

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 invasive mechanical ventilation, seeking after corresponding pathophysiological and biological characteristics. METHODS: Between March 22 and March 30, 2020 respiratory mechanics, gas exchanges, circulating endothelial cells (CEC) as markers of endothelial damage, and D-dimers were studied in 22 moderate-to-severe COVID-19 ARDS patients, 1 [1-4] day after intubation (median [IQR]). MEASUREMENTS AND MAIN RESULTS: Thirteen moderate and 9 severe COVID-19 ARDS patients were studied after initiation of high PEEP protective mechanical ventilation. We observed moderately decreased respiratory system compliance: 39.5 [33.1-44.7] mL/cmH2O and end-expiratory lung volume: 2100 [1721-2434] mL. Gas exchanges were characterized by hypercapnia 55 [44-62] mmHg, high physiological dead-space (VD/VT): 75 [69-85.5] % and ventilatory ratio (VR): 2.9 [2.2-3.4]. VD/VT and VR were significantly correlated: r2 = 0.24, p = 0.014. No pulmonary embolism was suspected at the time of measurements. CECs and D-dimers were elevated as compared to normal values: 24 [12-46] cells per mL and 1483 [999-2217] ng/mL, respectively. CONCLUSIONS: We observed early in the course of COVID-19 ARDS high VD/VT in association with biological markers of endothelial damage and thrombosis. High VD/VT can be explained by high PEEP settings and added instrumental dead space, with a possible associated role of COVID-19-triggered pulmonary microvascular endothelial damage and microthrombotic process.

[Venous thromboembolism and urological cancer: Epidemiology and therapeutically management]. / Maladie thromboembolique veineuse et cancers urologiques : épidémiologie et prise en charge thérapeutique.

INTRODUCTION: Active cancer is a risk factor in the occurrence of venous thromboembolism (VTE). This is the second cause of death for these patients. In onco-urology, some cancers are associated with an increased risk of VTE. The aim of this study was to propose a focus of epidemiology and VTE therapy management. MATERIAL AND METHODS: A systematic analysis of the PubMed® database was performed through the PRISMA methodology using the followings keywords : "neoplasm", "venous thromboembolism", "prophylaxis", "pulmonary embolism", "urology". The original papers were included with a priority on: meta-analyzes, literature reviews, randomized controlled trials and good-level proof cohort studies. Only publications in English or French have been selected. RESULTS: The incidence of VTE was more important in case of renal carcinomas (3.5%/year). When surgery was proposed cystectomy was the riskiest procedure (2.6 to 11.6% VTE). Chemotherapy alone was an important risk factor increasing by a factor of six the occurrence of VTE. Hormonotherapy also increased this risk by induced hypogonadism. The curative treatment for VTE associated with cancers has to be performed through the injection of low molecular weight heparin. The implantation of a prophylactic treatment was not systematic among patients diagnosed with urological cancer. CONCLUSION: The understanding of mechanisms associated with the occurrence of VTE among these patients has enabled to improve patient management, especially those suffering from urological cancer. Undeniably, frequency of VTE is probably underestimated by urologists during clinical practice.

Increase in both angiogenic and angiostatic mediators in patients with idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is associated with a marked pulmonary vascular remodeling. The aim of this study was to investigate a potential imbalance between angiogenic and angiostatic factors in this disease. METHODS AND RESULTS: Sixty-four subjects with IPF and 10 healthy control subjects (60-70 years old) were prospectively included in this multicenter study. Plasma levels of vascular endothelial growth factor A (VEGF-A), thrombospondin-1 (TSP-1) and stem cell factor (SCF) were determined by Elisa. Comparisons between IPF and controls were made using the Mann-Whitney U test. We also analyzed these soluble mediators in relation with IPF severity (DLCO<40% or>40%) predicted or total lung capacity (TLC) and forced vital capacity (FVC) (both<55% or>55% predicted) using the same test. VEGF-A plasma levels were increased in IPF vs. controls (P=0.0008) as well as those of TSP-1 (P=0.008), irrespective of the severity of the disease as reflected by DLCO, TLC or FVC values. In contrast, SCF levels were similar in IPF and controls. CONCLUSIONS: Factors modulating angiogenic responses are dysregulated in patients with IPF with increases in VEGF-A and TSP-1. The serial assessment of VEGF-A and TSP-1 during the follow-up and the search for potential relationships with the outcome of the disease might give us hints to the clinical implication of these results.

The profibrotic cytokine transforming growth factor-ß1 increases endothelial progenitor cell angiogenic properties.

BACKGROUND: Transforming growth factor-ß1 (TGF-ß1) is a profibrotic cytokine that plays a major role in vascular biology, and is known to regulate the phenotype and activity of various vascular cell populations. Because most fibrotic diseases, such as idiopathic pulmonary fibrosis (IPF), are associated with vascular remodeling, and as endothelial progenitor cells (EPCs) may be involved in this process, we investigated the impact of TGF-ß1 modulation of EPC angiogenic properties. METHODS: TGF-ß1 plasma levels were determined in 64 patients with IPF and compared with those in controls. The effect of TGF-ß1 on angiogenesis was studied in vivo in a Matrigel plug model and in vitro on endothelial colony-forming cells (ECFCs). We studied the effects of inhibiting the expression of the three main receptors of TGF-ß1 in ECFCs by using short interfering RNA. RESULTS: Total TGF-ß1 plasma levels were significantly increased in patients with IPF as compared with controls (P < 0.0001). TGF-ß1 had proangiogenic effects in vivo by increasing hemoglobin content and blood vessel formation in Matrigel plugs implanted in C57/Bl6 mice, and in vitro by enhancing ECFC viability and migration. The effects were abolished by silencing the three main TGF-ß1 receptors. CONCLUSIONS: TGF-ß1 is proangiogenic in vivo and induces ECFC angiogenic properties in vitro, suggesting that TGF-ß1 may play a role during vascular remodeling in fibrotic disease states via EPCs.

Osteoprotegerin, a new actor in vasculogenesis, stimulates endothelial colony-forming cells properties.

BACKGROUND: Osteoprotegerin (OPG), a soluble receptor of the tumour necrosis factor family, and its ligand, the receptor activator of nuclear factor-κB ligand (RANKL), are emerging as important regulators of vascular pathophysiology. OBJECTIVES: We evaluated their effects on vasculogenesis induced by endothelial colony-forming cells (ECFC) and on neovessel formation in vivo. METHODS: Effects of OPG and RANKL on in vitro angiogenesis were evaluated after ECFC incubation with OPG or RANKL (0-50 ng mL(-1)). Effects on microvessel formation were evaluated with an in vivo murin Matrigel plug assay. Vascularization was evaluated by measuring plug hemoglobin and vascular endothelial growth factor (VEGF)-R2 content 14 days after implantation. RESULTS: We found that ECFC expressed OPG and RANK but not RANKL mRNA. Treatment of ECFC with VEGF or stromal cell-derived factor-1 (SDF-1) upregulated OPG mRNA expression. OPG stimulated ECFC migration (P < 0.05), chemotaxis (P < 0.05) and vascular cord formation on Matrigel(®) (P < 0.01). These effects were correlated with SDF-1 mRNA overexpression, which was 30-fold higher after 4 h of OPG stimulation (P < 0.01). OPG-mediated angiogenesis involved the MAPK signaling pathway as well as Akt or mTOR cascades. RANKL also showed pro-vasculogenic effects in vitro. OPG combined with FGF-2 promoted neovessel formation in vivo, whereas RANKL had no effect. CONCLUSIONS: OPG induces ECFC activation and is a positive regulator of microvessel formation in vivo. Our results suggest that the OPG/RANK/RANKL axis may be involved in vasculogenesis and strongly support a modulatory role in tissue revascularization.

Distinct patterns of circulating endothelial cells in pulmonary hypertension.

The respective abundance of circulating endothelial cells and endothelial progenitor cells may reflect the balance between vascular injury and repair. As pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) can share features of pulmonary remodelling, we postulated that the two disorders might be associated with different types of pulmonary endothelial dysfunction. We studied 25 consecutive patients undergoing cardiac catheterisation for suspected pulmonary hypertension. Nine patients had PAH, nine had CTEPH, and seven had normal pulmonary arterial pressure and served as controls. Circulating endothelial cells were isolated with CD146-coated beads. CD34(+)CD133(+) cell and endothelial progenitor cell numbers were respectively determined by flow cytometry and cell culture, in peripheral vein and pulmonary artery blood. Plasma levels of soluble vascular endothelial growth factor (VEGF), soluble E-selectin and soluble vascular cell adhesion molecule (sVCAM) were measured by ELISA. No difference in progenitor counts or VEGF levels was found across the three groups. Compared to controls, circulating endothelial cell numbers were significantly increased in PAH but not in CTEPH, in keeping with the elevated soluble E-selectin and sVCAM levels found in PAH alone. In conclusion, PAH, in contrast to CTEPH, is associated with markers of vascular injury (circulating endothelial cells, soluble E-selectin and sVCAM) but not with markers of remodelling (endothelial progenitor cells, CD34(+)CD133(+) cells and VEGF).

Endothelial progenitor cells: characterization, in vitro expansion, and prospects for autologous cell therapy.

Injection of hematopoietic stem cells or endothelial progenitor cells (EPCs) expanded ex vivo has been shown to augment neovascularization in adult patients, but the precise origin and identity of the cell population responsible for these clinical benefits are controversial. The limited quantity of EPCs in the circulation has been the main obstacle to clinical trials. Several authors have therefore attempted to expand these cells ex vivo in order to obtain a homogeneous cell therapy product. One possible means of expanding EPCs ex vivo is to activate the thrombin receptor PAR-1 with the specific peptide SFLLRN. Indeed, PAR-1 activation promotes cell proliferation and C-X-C chemokine receptor type 4 (CXCR4) dependent migration and differentiation, with an overall angiogenic effect. This review summarizes the results and rationale of clinical trials of angiogenic therapy, the nature of EPCs, the different methods of ex vivo expansion, and current methods of quantification.

The angiopoietin pathway is modulated by PAR-1 activation on human endothelial progenitor cells.

OBJECTIVES: The importance of protease-activated receptor-1 (PAR-1) in blood vessel development has been shown in knock-out mice. As endothelial progenitor cells (EPCs) express functional PAR-1, we examined whether PAR-1 stimulation by the peptide SFLLRN interfered with the angiopoietin pathway, that is EPC commitment, proliferation and migration. METHODS AND RESULTS: Given the strong PAR-1 expression on CD34+ cells, we tested the effect of SFLLRN 75 micromol L(-1) on the emergence of EPCs from cord blood. PAR-1 activation did not modify the number of colonies or the day of emergence, in keeping with the lack of induction of angiopoietin 1 gene expression. Conversely, SFLLRN treatment of EPCs induced angiopoietin 2 gene expression and protein synthesis. Experiments with polyclonal blocking antibodies showed that angiopoietin 2 was involved in the proliferative effect of PAR-1 activation. PAR-1 activation also enhanced migration toward angiopoietin 1 in a Boyden chamber assay. CONCLUSIONS: Our study demonstrates that PAR-1-induced proliferation of EPCs involves angiopoietin 2. PAR-1 also enhances EPC migration toward angiopoietin 1. These findings might explain the role of thrombin in neovascularization via the angiopoietin pathway.

[Acute megakaryoblastic leukemia (AML-7) in a woman of 95 years]. / Leucémie aiguë mégacaryoblastique (LAM-7) chez une patiente de 95 ans.

Acute leukemia of megakaryocyte lineage (AML-7) is a rare entity defined by a blastic proliferation of which a part (>or= 50%) is represented by megakaryoblasts. We report the case of a 95 year old woman presenting a AML-7 secondary to a myelodysplastic syndrome (MDS), that represents an unusual form of MDS acutisation.