Antiviral Activities of Heparan Sulfate Mimetic RAFT Polymers Against Mosquito-borne Viruses.

Mosquito-borne viruses are a major worldwide health problem associated with high morbidity and mortality rates and significant impacts on national healthcare budgets. The development of antiviral drugs for both the treatment and prophylaxis of these diseases is thus of considerable importance. To address the need for therapeutics with antiviral activity, a library of heparan sulfate mimetic polymers was screened against dengue virus (DENV), Yellow fever virus (YFV), Zika virus (ZIKV), and Ross River virus (RRV). The polymers were prepared by RAFT polymerization of various acidic monomers with a target MW of 20 kDa (average Mn ∼ 27 kDa by GPC). Among the polymers, poly(SS), a homopolymer of sodium styrenesulfonate, was identified as a broad spectrum antiviral with activity against all the tested viruses and particularly potent inhibition of YFV (IC50 = 310 pM). Our results further uncovered that poly(SS) exhibited a robust inhibition of ZIKV infection in both mosquito and human cell lines, which points out the potential functions of poly(SS) in preventing mosquito-borne viruses associated diseases by blocking viral transmission in their mosquito vectors and mitigating viral infection in patients.

Apixaban overdose in children: case report and proposed management. A brief communication from the Pediatric and Neonatal Thrombosis and Hemostasis SSC of ISTH.

Background: Direct oral anticoagulants are commonly prescribed for adults and increasingly also for children requiring anticoagulation therapy. While household medications should not be accessible to children, accidental, and intentional overdoses occur. Key Clinical Question: How should apixaban overdose in children be managed?. Clinical Approach: We present a case of an accidental overdose with the factor Xa antagonist apixaban in a young child and propose an approach to the management of cases of apixaban overdose in children. Conclusion: Given the increasing use of direct oral anticoagulants, it is important to have an approach to the management of overdose of these medications.

Technical report: The clinically useful selection of proteins protocol: An approach to identify clinically useful proteins for validation.

Clinical proteomics studies aiming to develop markers of clinical outcome or disease typically involve distinct discovery and validation stages, neither of which focus on the clinical applicability of the candidate markers studied. Our clinically useful selection of proteins (CUSP) protocol proposes a rational approach, with statistical and non-statistical components, to identify proteins for the validation phase of studies that could be most effective markers of disease or clinical outcome. Additionally, this protocol considers commercially available analysis methods for each selected protein to ensure that use of this prospective marker is easily translated into clinical practice. SIGNIFICANCE: When developing proteomic markers of clinical outcomes, there is currently no consideration at the validation stage of how to implement such markers into a clinical setting. This has been identified by several studies as a limitation to the progression of research findings from proteomics studies. When integrated into a proteomic workflow, the CUSP protocol allows for a strategically designed validation study that improves researchers' abilities to translate research findings from discovery-based proteomics into clinical practice.

Plasma from patients with vaccine-induced immune thrombotic thrombocytopenia displays increased fibrinolytic potential and enhances tissue-type plasminogen activator but not urokinase-mediated plasminogen activation.

BACKGROUND: Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare complication of adenovirus vector-based COVID-19 vaccines. VITT is associated with markedly raised levels of D-dimer; yet, how VITT modulates the fibrinolytic system is unknown. OBJECTIVES: We aimed to compare changes in fibrinolytic activity in plasma from patients with VITT, patients diagnosed with venous thromboembolism (VTE) after vaccination but without VITT (VTE-no VITT), and healthy vaccinated controls. METHODS: Plasma levels of plasmin-antiplasmin (PAP) complexes, plasminogen, and alpha-2-antiplasmin (α2AP) from 10 patients with VITT, 10 patients with VTE-no VITT, and 14 healthy vaccinated controls were evaluated by enzyme-linked immunosorbent assay and/or Western blotting. Fibrinolytic capacity was evaluated by quantitating PAP levels at baseline and after ex vivo plasma stimulation with 50-nM tissue-type plasminogen activator (tPA) or urokinase for 5 minutes. RESULTS: Baseline PAP complex levels in control and VTE-no VITT individuals were similar but were ∼7-fold higher in plasma from patients with VITT (P < .0001). VITT samples also revealed consumption of α2AP and fibrinogenolysis consistent with a hyperfibrinolytic state. Of interest, VITT plasma produced significantly higher PAP levels after ex vivo treatment with tPA, but not urokinase, compared to the other groups, indicative of increased fibrinolytic potential. This was not due to D-dimer as addition of D-dimer to VTE-no VITT plasma failed to potentiate tPA-induced PAP levels. CONCLUSION: A marked hyperfibrinolytic state occurs in patients with VITT, evidenced by marked elevations in PAP, α2AP consumption, and fibrinogenolysis. An unidentified plasma cofactor that selectively potentiates tPA-mediated plasminogen activation also appears to exist in the plasma of patients with VITT.

Apixaban for Prevention of Thromboembolism in Pediatric Heart Disease.

BACKGROUND: Children with heart disease frequently require anticoagulation for thromboprophylaxis. Current standard of care (SOC), vitamin K antagonists or low-molecular-weight heparin, has significant disadvantages. OBJECTIVES: The authors sought to describe safety, pharmacokinetics (PK), pharmacodynamics, and efficacy of apixaban, an oral, direct factor Xa inhibitor, for prevention of thromboembolism in children with congenital or acquired heart disease. METHODS: Phase 2, open-label trial in children (ages, 28 days to <18 years) with heart disease requiring thromboprophylaxis. Randomization 2:1 apixaban or SOC for 1 year with intention-to-treat analysis. PRIMARY ENDPOINT: a composite of adjudicated major or clinically relevant nonmajor bleeding. Secondary endpoints: PK, pharmacodynamics, quality of life, and exploration of efficacy. RESULTS: From 2017 to 2021, 192 participants were randomized, 129 apixaban and 63 SOC. Diagnoses included single ventricle (74%), Kawasaki disease (14%), and other heart disease (12%). One apixaban participant (0.8%) and 3 with SOC (4.8%) had major or clinically relevant nonmajor bleeding (% difference -4.0 [95% CI: -12.8 to 0.8]). Apixaban incidence rate for all bleeding events was nearly twice the rate of SOC (100.0 vs 58.2 per 100 person-years), driven by 12 participants with ≥4 minor bleeding events. No thromboembolic events or deaths occurred in either arm. Apixaban pediatric PK steady-state exposures were consistent with adult levels. CONCLUSIONS: In this pediatric multinational, randomized trial, bleeding and thromboembolism were infrequent on apixaban and SOC. Apixaban PK data correlated well with adult trials that demonstrated efficacy. These results support the use of apixaban as an alternative to SOC for thromboprophylaxis in pediatric heart disease. (A Study of the Safety and Pharmacokinetics of Apixaban Versus Vitamin K Antagonist [VKA] or Low Molecular Weight Heparin [LMWH] in Pediatric Subjects With Congenital or Acquired Heart Disease Requiring Anticoagulation; NCT02981472).

Surgeons' perspectives on operation report documentation.

BACKGROUND: Operation report documentation is essential for safe patient care and team communication, yet it is often imperfect. This qualitative study aims to understand surgeons' perspectives on operation report documentation, with surgeons reviewing cleft palate repair operation reports. It aims to determine how surgeons write an operation report (in narrative and synoptic report formats) and explore the consequences of incomplete documentation on patient care. METHODS: A qualitative semi-structured interview was conducted with cleft surgeons who were asked to consider operation reports and hypothetical clinical cases. Eight operation reports performed at one centre for cleft palate repair were randomly selected for review. RESULTS: An operation report's purpose-patient care, complication documentation, future surgery, and research-will influence the detail documented. All cleft palate repair operation reports had important information missing. Synoptic report writing provides clearer documentation; however, narrative report writing may be a more robust communication and education tool. Surgeons described a bell-curve response in the level of training required to document an operation report-residents knew too little, fellows documented clearly, and Consultants documented briefer reports to highlight salient points. CONCLUSIONS: An understanding of surgeons' perspectives on operation report documentation is richer after this study. Surgeons know that clear documentation is essential for patient care and a skill that must be taught to trainees; barriers may be the documentation method. The flexibility of a hybrid operation report format is necessary for surgical care.

International Survey of the Management of Disseminated Intravascular Coagulation Among Pediatric and Neonatal Health Care Practitioners.

The International Society of Thrombosis and Hemostasis (ISTH) provides objective disseminated intravascular coagulation (DIC) measurement through diagnostic criteria validated in adults. The applicability of these criteria in pediatric and neonatal DIC is controversial and unvalidated. Primary objective: to evaluate current practice in pediatric and neonatal DIC management among different specialties. Secondary objective: to understand the potential impact of developmental hemostasis on DIC laboratory evaluation. We performed a multicenter survey between January and September 2016. The questionnaire was distributed internationally through professional societies. In all, 211 responses were received, of which 160 were full responses and 51 were partial. Overall, 85% of respondents practiced in tertiary academic centers; 70% practiced in pediatric-only hospitals. The majority of respondents (42%) used their personal clinical experience in the management of DIC. Sixty percent of respondents treated DIC until the resolution of both clinical and laboratory parameters. Laboratory investigations were monitored in the majority of DIC cases without thrombosis or bleeding (80%); age-specific reference ranges for tests were lacking in 20% of pediatric-only hospitals and 35% of combined pediatric/adult hospitals. Adherence to standardized DIC guidelines was poor but varied by geographical location. This survey reveals variable practices among pediatricians in the management of DIC. Further studies are needed to validate the DIC diagnostic criteria in children.

Corrigendum to 'The Hemophilia Joint Health Score version 2.1 Validation in Adult Patients Study: A multicenter international study' [Research and Practice in Thrombosis and Haemostasis, 6/2, (2022) e12690].

[This corrects the article DOI: 10.1002/rth2.12690.].

What did we learn (and did not learn) from the pediatric direct oral anticoagulant trials, and how might we better design pediatric anticoagulant trials in the future?

A State of the Art lecture titled "What the direct oral anticoagulants (DOACs) trials did and didn't tell us" was presented at the International Society on Thrombosis and Haemostasis (ISTH) Congress in 2022. The use of DOACs in children is of particular interest as they exhibit several advantages over conventional anticoagulation agents most commonly used in pediatrics. To date, several DOAC pediatric investigational programs (PIPs) have been completed, and although they have provided some of the best quality of evidence in pediatric anticoagulation therapy, the data generated by these trials remain limited. Here, we review and summarize the currently available data provided by the DOAC PIPs, provide perspectives on what we have and have not learned from these trials, and how we might leverage this knowledge to optimize the design of future anticoagulant PIPs. Finally, we summarize relevant new data on this topic presented during the 2022 ISTH Congress.

Protocol for the Investigation of Plasma and Whole Blood Clot Property of Fibrin Fiber Thickness Using Scanning Electron Microscopy.

Blood clot formation represents a key component of the coagulation process for preventing excessive hemorrhage. The structural characteristics of blood clots are associated with their strength and susceptibility to fibrinolysis. Scanning electron microscopy is a technique that allows for state-of-the-art image capture of blood clots, providing visualization of topography, fibrin thickness, fibrin network density, and blood cell involvement and morphology. In this chapter, we provide a detailed protocol for characterization of plasma and whole blood clot structure using SEM, covering the spectrum from blood collection, in vitro clot formation, sample preparation for SEM, imaging, and image analysis, specifically focusing on the measurement of fibrin fiber thickness.

A systems immunology study comparing innate and adaptive immune responses in adults to COVID-19 mRNA and adenovirus vectored vaccines.

Identifying the molecular mechanisms that promote optimal immune responses to coronavirus disease 2019 (COVID-19) vaccination is critical for future rational vaccine design. Here, we longitudinally profile innate and adaptive immune responses in 102 adults after the first, second, and third doses of mRNA or adenovirus-vectored COVID-19 vaccines. Using a multi-omics approach, we identify key differences in the immune responses induced by ChAdOx1-S and BNT162b2 that correlate with antigen-specific antibody and T cell responses or vaccine reactogenicity. Unexpectedly, we observe that vaccination with ChAdOx1-S, but not BNT162b2, induces an adenoviral vector-specific memory response after the first dose, which correlates with the expression of proteins with roles in thrombosis with potential implications for thrombosis with thrombocytopenia syndrome (TTS), a rare but serious adverse event linked to adenovirus-vectored vaccines. The COVID-19 Vaccine Immune Responses Study thus represents a major resource that can be used to understand the immunogenicity and reactogenicity of these COVID-19 vaccines.

Using an electronic medical record patient portal for warfarin self-management: Empowering children and parents.

Background: Many children taking warfarin perform their international normalized ratio (INR) at home, with results phoned to a clinician who instructs warfarin dosing. Data suggest that parents can be supported to make warfarin dosing decisions themselves, a process known as patient self-management (PSM). Objectives: This study aimed to determine the suitability and acceptability of warfarin PSM in children using the Epic Patient Portal. Methods: Children currently performing INR patient self-testing were eligible. Participation involved an individualized education session, adherence to the PSM program, and participation in phone interviews. Clinical outcomes (INR time in therapeutic range and safety outcomes), patient portal functionality, and family experience were assessed. The hospital human research ethics committee approved the study and consent was obtained from parents/guardians. Results: Twenty-four families undertook PSM. The median age of children was 11 years and all children had congenital heart disease. A median of 13 INRs was uploaded to the portal per family (range, 8-47) across a 10-month period. Before PSM, the mean time the INR was in therapeutic range was 71%; this increased to 79.9% during PSM (difference: P < .001). No adverse events were encountered. Eight families participated in a phone interview. The major theme identified was empowerment; minor themes that emerged included "gaining knowledge," "trust and responsibility builds confidence," "saving time," and "resources as a safety net." Conclusion: This study demonstrates that communication via the Epic Patient Portal is satisfactory to families and offers a suitable option for PSM for children. Importantly, PSM empowers and builds confidence in families to facilitate management of their child's health.

Platelet function in neonates and children.

Platelets are major regulators of haemostasis and coagulation. The primary role of platelets in coagulation is to form a stable clot and stop bleeding. Studies of platelet phenotype and function in neonates and children have been restricted by the large volumes required for many common platelet function tests such as platelet aggregometry. Developmental changes in platelets have not been as well described as developmental changes in plasma coagulation proteins, and overall, platelet phenotype and function in neonates and children has been understudied when compared to adults. Recent developments in more sensitive platelet function testing methods requiring smaller blood volumes such as flow cytometry has enabled recent studies to further investigate platelet phenotype and function in neonates and children. In this review we will provide an overview of recent advances from the past five years in platelets in the context of developmental haemostasis, as well as the role of platelets in neonatal paediatric disease.

Biomarkers in pediatric venous thromboembolism: a systematic review of the literature.

BACKGROUND: Accurate prediction of the individual risk of venous thromboembolism (VTE) remains suboptimal in children, and biomarkers are currently not used to stratify the risk of VTE in children. OBJECTIVES: This study aimed to assess which biological or radiological biomarkers may predict VTE or VTE complications in children. PATIENTS/METHODS: A literature search was performed for peer-reviewed publications (1990-2022). We included studies addressing the use of biomarkers for patients aged 29 days to 18 years to predict VTE or its complications, including but not limited to TE-related death, VTE recurrence, or postthrombotic syndrome. Given the heterogeneity of the study designs, populations, and outcomes, no quantitative data synthesis was performed. RESULTS: Forty studies were included, totaling 10,987 participants (median age: 4.7 years). Reports were often lacking critical methodological data, including blood collection method (68% of studies) and timepoints, laboratory testing technique (41%), or primary outcome definition (20%). Forty-six individual biomarkers were assessed for VTE prediction (32 studies, 9525 participants), including d-dimers, fibrinogen, platelet count, white blood cell count, and factor VIII. Albumin, C-reactive protein, d-dimers, factor VIII, and thrombin-antithrombin levels showed promising results for VTE prediction. In 9 studies (1606 participants), no biomarker was consistently predictive of postthrombotic syndrome, VTE persistence, or VTE recurrence in children. CONCLUSIONS: Several candidate biomarkers were promising in the prediction of VTE in children. Still, discrepancies between different studies and the high risk of bias from the current literature prevent their widespread use in the clinical setting. Further prospective research in various pediatric subpopulations is required.

Blood Collection Processing and Handling for Plasma and Serum Proteomics.

The plasma and serum proteome has enormous potential as a tool for understanding the health of a number of physiological systems. Despite this potential, the use of plasma and serum proteomics clinically and for research is limited, and there are no strict guidelines on how samples should be collected and prepared for proteomic analysis. Given the sensitivity of proteomic analysis, there are a number of pre-analytical variables that should be considered and determined prior to undertaking proteomics-based methodologies.In this chapter, we provide an example of a blood processing protocol and highlight major considerations for pre-analytical variables involving the collection, processing, and handling of blood samples for plasma and serum proteomics. We provide comprehensive notes on aspects of the protocol that must be considered before commencing sample collections for a proteomic study as well as a thorough checklist to be used when designing new proteomic studies.

Proteomic Applications and Considerations: From Research to Patient Care.

Despite technological advancements in the field of proteomics, the rate at which serum and plasma biomarkers identified using proteomic approaches are translated into clinical use remains extremely low. In this chapter, we describe recent technological advancements and analytical strategies in proteomic methods. We also describe the progress of proteomic blood-based biomarkers to date and discuss what the future of proteomics might entail with the use of multi-omic approaches and implementing machine learning on large proteomic datasets. Lastly, we provide several key considerations for biomarker studies, ranging from sample type to the use of reference samples, in order to achieve progress from bench to bedside, ultimately improving patient diagnosis, disease, and/or therapeutic monitoring and care.

Children and Snakebite: Snake Venom Effects on Adult and Paediatric Plasma.

Snakebite is a globally neglected tropical disease, with coagulation disturbances being the primary pathology of many deadly snake venoms. Age-related differences in human plasma have been abundantly reported, yet the effect that these differences pose regarding snakebite is largely unknown. We tested for differences in coagulotoxic effects (via clotting time) of multiple snake venoms upon healthy human adult (18+) and paediatric (median 3.3 years old) plasma in vivo and compared these effects to the time it takes the plasmas to clot without the addition of venom (the spontaneous clotting time). We tested venoms from 15 medically significant snake species (from 13 genera) from around the world with various mechanisms of coagulotoxic actions, across the three broad categories of procoagulant, pseudo-procoagulant, and anticoagulant, to identify any differences between the two plasmas in their relative pathophysiological vulnerability to snakebite. One procoagulant venom (Daboia russelii, Russell's Viper) produced significantly greater potency on paediatric plasma compared with adult plasma. In contrast, the two anticoagulant venoms (Pseudechis australis, Mulga Snake; and Bitis cornuta, Many-horned Adder) were significantly more potent on adult plasma. All other procoagulant venoms and all pseudo-procoagulant venoms displayed similar potency across both plasmas. Our preliminary results may inform future studies on the effect of snake venoms upon plasmas from different age demographics and hope to reduce the burden of snakebite upon society.

Changes in von Willebrand Factor Multimers, Concentration, and Function During Pediatric Extracorporeal Membrane Oxygenation.

OBJECTIVES: 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. DESIGN: Prospective observational study of pediatric ECMO patients from April 2017 to May 2019. SETTING: The PICU in a large, tertiary referral pediatric ECMO center. PATIENTS: Twenty-five neonates and children (< 18 yr) supported by venoarterial ECMO. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: 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. CONCLUSIONS: 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.