Shear Forces Induced Platelet Clearance Is a New Mechanism of Thrombocytopenia.

Background: Thrombocytopenia has been consistently described in patients with extracorporeal membrane oxygenation (ECMO) and associated with poor outcome. However, the prevalence and underlying mechanisms remain largely unknown, and a device-related role of ECMO in thrombocytopenia has been hypothesized. This study aims to investigate the mechanisms underlying thrombocytopenia in ECMO patients.

Inflammatory markers and auto-Abs to type I IFNs in COVID-19 convalescent plasma cohort study.

Background: COVID-19 convalescent plasma (CCP) contains neutralising anti-SARS-CoV-2 antibodies that may be useful as COVID-19 passive immunotherapy in patients at risk of developing severe disease. Such plasma from convalescent patients may also have additional immune-modulatory properties when transfused to COVID-19 patients.

Methods: CCP (n = 766) was compared to non-convalescent control plasma (n = 166) for soluble inflammatory markers, ex-vivo inflammatory bioactivity on endothelial cells, neutralising auto-Abs to type I IFNs and reported adverse events in the recipients.

Modulation of inflammatory M1-macrophages phenotype by valvular interstitial cells.

Background: Aortic valve stenosis involves inflammation, excess deposition of a collagen-rich extracellular matrix, and calcification. Recent studies have shown that M1 or inflammatory macrophages derived from infiltrating monocytes promote calcification of valvular interstitial cells, the most prevalent cell type of the aortic valve. We hypothesized that valvular interstitial cells could modulate inflammatory macrophages phenotype.

Thrombus formation during ECMO: Insights from a detailed histological analysis of thrombus composition.

Objectives: Intra-device thrombosis remains one of the most common complications during extracorporeal membrane oxygenation (ECMO). Despite anticoagulation, approximately 35% of patients develop thrombi in the membrane oxygenator, pump heads, or tubing. The aim of this study was to describe the molecular and cellular features of ECMO thrombi and to study the main drivers of thrombus formation at different sites in the ECMO circuits.

Neutrophil extracellular traps (NETs) infiltrate haematoma and surrounding brain tissue after intracerebral haemorrhage: A post-mortem study.

Aims: Because of their prothrombotic and neuroinflammatory effects, neutrophils and neutrophil extracellular traps (NETs) represent interesting therapeutic targets for spontaneous intracerebral haemorrhage (sICH). We investigated the presence, spatial and temporal distribution of NETs in a human sICH post-mortem study.

Methods: From 2005 to 2019, all sICH patients who came to autopsy within the first month after stroke were included and grouped according to the timing of death: 72 h, 4-7 days, 8-15 days and >15 days after ICH onset.

Vascular Endothelial Damage in the Pathogenesis of Organ Injury in Severe COVID-19.

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Time Course of Reendothelialization with Polyzene-F Nanocoated Cobra PzF™ Coronary Stent on Rabbit Iliac Arteries.

Purpose: Evaluation of reendothelialization with a new thin struts cobalt chromium alloy stent coated with a nano-layer of Polyzene™-F (PzF) in a rabbit iliac artery model.

Methods: Fifteen stented external rabbit iliac arteries were harvested at Day 7 for electron microscopy analysis following Cobra PzF stents implantation to assess reendothelialization and compare to historical data. Ten additional rabbits were used to assess time course of reendothelialization at 3 and 5 days.

Texture parameters of R2* maps are correlated with iron concentration and red blood cells count in clot analogs: A 7-T micro-MRI study.

Background And Purpose: Previous studies have suggested that mechanical revascularization in acute ischemic stroke (AIS) patients could be affected by clot histology. In this 7-T micro-MRI study, we used R2* relaxometry of clot analogs to evaluate the relationship between texture parameters of R2* maps and clot constituents.

Materials And Methods: Twelve AIS clot analogs were experimentally generated to obtain a wide range of red blood cell concentrations.

Arterial Pulsatility and Circulating von Willebrand Factor in Patients on Mechanical Circulatory Support.

Background: The main risk factor for bleeding in patients with continuous-flow mechanical circulatory support (CF-MCS) is the acquired von Willebrand factor (VWF) defect related to the high shear-stress forces developed by these devices. Although a higher bleeding rate has been reported in CF-MCS recipients who had reduced pulsatility, the relation between pulsatility and the VWF defect has never been studied.

Objectives: The purpose of this study was to investigate the relation between pulsatility and VWF under CF-MCS.

Leptin induces osteoblast differentiation of human valvular interstitial cells via the Akt and ERK pathways.

Aims: Calcific aortic valve disease (CAVD) affects 2-6% of the population over 65 years, and age, gender, smoking, overweight, dyslipidemia, diabetes contribute to the development of this disease. CAVD results, in part, from the osteoblast differentiation of human valvular interstitial cells (VICs). This study aims to elucidate the effects of leptin on osteoblast phenotype of VICs and the signalling pathways involved.

Von Willebrand Factor Multimers during Transcatheter Aortic-Valve Replacement.

Background: Postprocedural aortic regurgitation occurs in 10 to 20% of patients undergoing transcatheter aortic-valve replacement (TAVR) for aortic stenosis. We hypothesized that assessment of defects in high-molecular-weight (HMW) multimers of von Willebrand factor or point-of-care assessment of hemostasis could be used to monitor aortic regurgitation during TAVR.

Methods: We enrolled 183 patients undergoing TAVR.

M1 and M2 macrophage proteolytic and angiogenic profile analysis in atherosclerotic patients reveals a distinctive profile in type 2 diabetes.

This study aimed to investigate atherosclerotic mediators' expression levels in M1 and M2 macrophages and to focus on the influence of diabetes on M1/M2 profiles. Macrophages from 36 atherosclerotic patients (19 diabetics and 17 non-diabetics) were cultured with interleukin-1β (IL-1β) or IL-4 to induce M1 or M2 phenotype, respectively. The atherosclerotic mediators' expression was evaluated by quantitative reverse transcription-polymerase chain reaction (RT-PCR).

Von Willebrand factor as a biological sensor of blood flow to monitor percutaneous aortic valve interventions.

Rationale: Percutaneous aortic valve procedures are a major breakthrough in the management of patients with aortic stenosis. Residual gradient and residual aortic regurgitation are major predictors of midterm and long-term outcome after percutaneous aortic valve procedures. We hypothesized that (1) induction/recovery of high molecular weight (HMW) multimers of von Willebrand factor defect could be instantaneous after acute changes in blood flow, (2) a bedside point-of-care assay (platelet function analyzer-closure time adenine DI-phosphate [PFA-CADP]), reflecting HMW multimers changes, could be used to monitor in real-time percutaneous aortic valve procedures.

Alterations in neutrophil production and function at an early stage in the high-fructose rat model of metabolic syndrome.

Background: Although neutrophils are crucially involved in inflammation, they have received only little attention in metabolic syndrome (MetS). We hypothesized that neutrophil infiltration into adipose tissue (AT) may occur at an early stage of MetS, in association with modulation of major functions of neutrophils and of their bone marrow production.

Methods: Fifty-six male Sprague-Dawley rats were fed regular (control rats (CRs)) or high-fructose (60%; fructose-fed rats (FFRs)) diets.

Carbon monoxide improves cardiac function and mitochondrial population quality in a mouse model of metabolic syndrome.

Aims: Metabolic syndrome induces cardiac dysfunction associated with mitochondria abnormalities. As low levels of carbon monoxide (CO) may improve myocardial and mitochondrial activities, we tested whether a CO-releasing molecule (CORM-3) reverses metabolic syndrome-induced cardiac alteration through changes in mitochondrial biogenesis, dynamics and autophagy.

Methods And Results: Mice were fed with normal diet (ND) or high-fat diet (HFD) for twelve weeks.

The presence of apoptotic bone marrow cells impairs the efficacy of cardiac cell therapy.

Injection of autologous bone marrow cells into infarcted myocardium has been proposed to limit the deterioration of cardiac function following myocardial infarction (MI); unfortunately, the beneficial effects observed have been modest. One of the limiting factors is believed to be poor local survival of the injected cells, but the potential impact of apoptosis among the injected cells has yet to be assessed. Therefore, this study aimed to quantify the apoptosis rate in bone marrow mononuclear cells (BMMCs) prepared for cardiac therapy, and to analyze their effects in vitro on cardiomyoblast apoptosis and in vivo on cardiac function recovery following MI.

Atherosclerotic-like process in aortic stenosis: activation of the tissue factor-thrombin pathway and potential role through osteopontin alteration.

Background: We recently demonstrated in an experimental model the expression of tissue factor (TF) in aortic valves. Thrombin, generated at the end of the TF-initiated coagulation cascade, has been shown to cleave the anti-calcific osteopontin (OSP) liberating the pro-inflammatory OSP N-half.

Objectives: We hypothesized that TF might play an important role in calcific aortic valve stenosis (AS) through thrombin generation and hence evaluated the valvular expression of TF and its inhibitor (TF pathway inhibitor), α-thrombin, OSP and its thrombin-cleaved form (OSP N-half).

Experimental off-pump transventricular pulmonary valve replacement using a self-expandable valved stent: A new approach for pulmonary incompetence after repaired tetralogy of Fallot?

Objective: Off-pump valve replacement using self-expandable stents is an emerging technique for pulmonary valve disease. However, significant limitations are the lack of easily available valve substitute to be inserted within the stent and, in the setting of repaired tetralogy of Fallot, the existence of huge pulmonary trunk. We report the first experimental results of a transventricular approach using a decellularized porcine xenograft mounted in a self-expandable stent.

Inhibition of tissue factor-factor VIIa proteolytic activity blunts hepatic metastasis in colorectal cancer.

Background: Expression of the principal initiator of coagulation, tissue factor (TF), by colorectal cancer (CRC) cells is involved in tumoral angiogenesis and metastasis progression, after binding of factor VIIa (FVIIa) to TF and generation of TF-FVIIa activity. We thus hypothesized that inhibition of the TF pathway by active site-blocked FVIIa (FFR-FVIIa) may prevent the development of hepatic metastasis in CRC.

Methods: Rat tumoral cells (DHDK12 proB cells) expressing high levels of TF were injected in the portal vein in syngenic BDIX rats.

Comparison of blood activation in the wound, active vent, and cardiopulmonary bypass circuit.

Background: During cardiopulmonary bypass, aspirated blood exhibits strong activation features, but the triggering event remains unclear. Contact of blood with the pericardial cavity and surgical wound has been advocated as the main trigger, but suction forces are also considered as a possible contributor. We thus designed a study to identify the possible causes involved in this activation.

Beneficial effects of fenofibrate on plaque thrombogenicity and plaque stability in atherosclerotic rabbits.

Background: Fibrates are peroxisome proliferator-activated receptor alpha (PPARalpha) agonists which modulate many aspects of lipoprotein metabolism and inflammation. They have been recently demonstrated to inhibit in vitro expression of tissue factor (TF), the main initiator of blood coagulation, which probably plays a pivotal role in thrombotic complications after plaque rupture. We investigated whether a 4-week fenofibrate treatment might affect the TF expression and cellular modifications in angioplasty-induced rabbit plaque rupture.

Identification of tissue factor in experimental aortic valve sclerosis.

Background: Aortic valve sclerosis (AVS) shares epidemiological and histological similarities with atherosclerosis. Tissue factor (TF), the main initiator of blood coagulation, is present in atherosclerotic plaques and contributes to their thrombogenicity. We aimed to analyze valvular TF expression in addition to other components of atherosclerosis in two models of AVS.