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To investigate changes in von Willebrand factor (VWF) concentration, function, and multimers during pediatric extracorporeal membrane oxygenation (ECMO) and determine whether routine monitoring of VWF during ECMO would be useful in predicting bleeding.Prospective observational study of pediatric ECMO patients from April 2017 to May 2019.The PICU in a large, tertiary referral pediatric ECMO center.Twenty-five neonates and children (18 yr) supported by venoarterial ECMO.None.Arterial blood samples were collected within 24 hours pre-ECMO, daily for the first 5 days of ECMO, every second day until decannulation, and 24 hours post-ECMO. The STA R Max analyzer was used to measure VWF antigen (VWF:Ag) and ristocetin cofactor (VWF:RCo) activity. VWF collagen binding (VWF:CB) was measured using an enzyme-linked immunosorbent assay. VWF multimers were measured using the semi-automated Hydragel 11 VWF Multimer assay. Corresponding clinical data for each patient was also recorded. A total of 25 venoarterial ECMO patients were recruited (median age, 73 d; interquartile range [IQR], 3 d to 1 yr). The median ECMO duration was 4 days (IQR, 3-8 d) and 15 patients had at least one major bleed during ECMO. The percentage of high molecular weight multimers (HMWM) decreased and intermediate molecular weight multimers increased while patients were on ECMO, irrespective of a bleeding status. VWF:Ag increased and the VWF:RCo/VWF:Ag and VWF:CB/VWF:Ag ratios decreased while patients were on ECMO compared with the baseline pre-ECMO samples and healthy children.Neonates and children on ECMO exhibited a loss of HMWM and lower VWF:CB/VWF:Ag and VWF:RCo/VWF:Ag ratios compared with healthy children, irrespective of major bleeding occurring. Therefore, monitoring VWF during ECMO would not be useful in predicting bleeding in these patients and changes to other hemostatic factors should be investigated to further understand bleeding during ECMO.

To investigate platelet pathophysiology associated with pediatric extracorporeal membrane oxygenation (ECMO).Prospective observational study of neonatal and pediatric ECMO patients from September 1, 2016, to December 31, 2019.The PICU in a large tertiary referral pediatric ECMO center.Eighty-seven neonates and children (18 yr) supported by ECMO.None.Arterial blood samples were collected on days 1, 2, and 5 of ECMO and were analyzed by whole blood flow cytometry. Corresponding clinical data for each patient was also recorded. A total of 87 patients were recruited (median age, 65 d; interquartile range [IQR], 7 d to 4 yr). The median duration of ECMO was 5 days (IQR, 3-8 d) with a median length of stay in PICU and hospital of 18 days (IQR, 10-29 d) and 35 days (IQR, 19-75 d), respectively. Forty-two patients (48%) had at least one major bleed according to a priori determined definitions, and 12 patients (14%) had at least one thrombotic event during ECMO. Platelet fibrinogen receptor expression decreased (median fluorescence intensity [MFI], 29,256 vs 26,544; p = 0.0005), while von Willebrand Factor expression increased (MFI: 7,620 vs 8,829; p = 0.0459) from day 2 to day 5 of ECMO. Platelet response to agonist, Thrombin Receptor Activator Peptide 6, also decreased from day 2 to day 5 of ECMO, as measured by binding with anti-P-selectin, PAC-1 (binds activated GPIIb/IIIa), and anti-CD63 monoclonal antibodies (P-selectin area under the curve [AUC]: 63.46 vs 42.82, respectively, p = 0.0022; PAC-1 AUC: 93.75 vs 74.46, p = 0.0191; CD63 AUC: 55.69 vs 41.76, p = 0.0020).The loss of platelet response over time may contribute to bleeding during ECMO. These novel insights may be useful in understanding mechanisms of bleeding in pediatric ECMO and monitoring platelet markers clinically could allow for prediction or early detection of bleeding and thrombosis.

International audience; The study of proteins circulating in blood offers tremendous opportunities to diagnose, stratify, or possibly prevent diseases. With recent technological advances and the urgent need to understand the effects of COVID-19, the proteomic analysis of blood-derived serum and plasma has become even more important for studying human biology and pathophysiology. Here we provide views and perspectives about technological developments and possible clinical applications that use mass-spectrometry(MS)- or affinity-based methods. We discuss examples where plasma proteomics contributed valuable insights into SARS-CoV-2 infections, aging, and hemostasis and the opportunities offered by combining proteomics with genetic data. As a contribution to the Human Proteome Organization (HUPO) Human Plasma Proteome Project (HPPP), we present the Human Plasma PeptideAtlas build 2021-07 that comprises 4395 canonical and 1482 additional nonredundant human proteins detected in 240 MS-based experiments. In addition, we report the new Human Extracellular Vesicle PeptideAtlas 2021-06, which comprises five studies and 2757 canonical proteins detected in extracellular vesicles circulating in blood, of which 74% (2047) are in common with the plasma PeptideAtlas. Our overview summarizes the recent advances, impactful applications, and ongoing challenges for translating plasma proteomics into utility for precision medicine.

Proteomics, the simultaneous study of all proteins in a given cell, tissue or organism, is an innovative approach used to identify novel markers for diagnosis, prognosis and the pathophysiological mechanisms associated with diseases. Proteomic methodologies have been used in a variety of contexts such as investigating changes in protein abundance that may occur with disease presence, the response to therapeutic treatments as well as the impacts of age on the plasma proteome.Over the last decade, significant technological advancements in proteomic techniques have resulted in an increase in the use of proteomics in thrombosis and hemostasis research, particularly in order to identify relevant and novel clinical markers associated with bleeding and thrombosis. This mini-review explores the use of proteomics in the setting of thrombosis and hemostasis from 2010-2020, across five main domains (platelets, blood clot composition, stroke, venous thromboembolism, and therapeutics), as well as provides insights into key considerations for conducting proteomic studies.

Over the last decade, the use of proteomics in the setting of prematurity has increased and has enabled researchers to successfully identify biomarkers for an array of associated morbidities. The objective of this scoping review was to identify the existing literature, as well as any knowledge gaps related to proteomic biomarker discoveries in the setting of prematurity. A scoping review was conducted using PubMed, Embase and Medline databases following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. The study selection process yielded a total of 700 records, of which 13 studies were included in this review. Most studies used a tandem Mass Spectrometry (MS/MS) proteomics approach to identify key biomarkers. The corresponding studies identified proteins associated with retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), necrotising enterocolitis (NEC), late onset sepsis (LOS) and gestational age. This scoping review demonstrates the limited use of proteomics to identify biomarkers associated with severe complications of prematurity. Further research is warranted to identify biomarkers of other important morbidities associated with prematurity, such as intraventricular haemorrhage (IVH) and cerebral palsy, and to investigate the mechanisms associated with these outcomes.

BACKGROUND: Type 1 diabetes mellitus (T1DM) is a metabolic disease characterized by dysglycaemia. Cardiovascular disease (CVD) is a major complication among T1DM patients and the leading cause of mortality later in life. METHODS: The study subjects consisted of T1DM children with poor glycemic control (HbA1c > 7.5%) and healthy age and gender matched controls. Venous blood samples were collected and tested by utilizing a novel immunoassay panel with 96 protein biomarkers. Data were analyzed using non-linear regression analysis and the expression of biomarkers was compared between T1DM and healthy control groups using an unpaired student's t-test. Dynamic principal component analysis (PCA) was operated based on the differentially expressed proteins. RESULTS: Ten T1DM children and 10 healthy controls were analyzed. Twelve CVD markers show significant differential expression between T1DM patients and healthy controls (p

Bivalirudin is a reversible direct thrombin inhibitor that inhibits both bound and free thrombin and binds to the active (catalytic) and fibrinogen-binding sites of thrombin, with high affinity and specificity. Off-label use of bivalirudin in the paediatric population has increased, as an alternative to heparin, particularly in the setting of anticoagulation for patients undergoing coronary bypass surgery (CPB), extracorporeal life support (ECLS) and those on ventricular assist devices (VAD). This study aimed to determine the age-specific in vitro effect of bivalirudin in children compared to adults. Age-specific pools (neonates, ≤2 years,2 to 5 years, 6 to 10 years, 11 to 17 years and Adults) were prepared using platelet poor plasma samples from 20 individuals per age group. Pooled plasma was spiked with increasing concentrations of Bivalirudin (from 0 g/mL to 10μg/mL), and thrombin inhibition was measured using standard coagulation assays. There was a significantly increased response to bivalirudin across all paediatric age groups as compared to adults. The age-specific difference in response to bivalirudin was specifically evident in neonates, where the potential to generate thrombin was decreased 2-fold compared to adults (p 0.001). Our findings support the concept of age-specific pharmaco-dynamic responses to Bivalirudin and support the need for further ex vivo studies in hospitalised children to determine accurate clinical dosing recommendations.