Background

Trauma is the leading cause of morbidity and mortality in children in the United States. The antifibrinolytic drug tranexamic acid (TXA) improves survival in adults with traumatic hemorrhage, however, the drug has not been evaluated in a clinical trial in severely injured children. We designed the Traumatic Injury Clinical Trial Evaluating Tranexamic Acid in Children (TIC-TOC) trial to evaluate the feasibility of conducting a confirmatory clinical trial that evaluates the effects of TXA in children with severe trauma and hemorrhagic injuries.

Methods

Children with severe trauma and evidence of hemorrhagic torso or brain injuries will be randomized to one of three arms: (1) TXA dose A (15 mg/kg bolus dose over 20 min, followed by 2 mg/kg/hr infusion over 8 h), (2) TXA dose B (30 mg/kg bolus dose over 20 min, followed by 4 mg/kg/hr infusion over 8 h), or (3) placebo. We will use permuted-block randomization by injury type: hemorrhagic brain injury, hemorrhagic torso injury, and combined hemorrhagic brain and torso injury. The trial will be conducted at four pediatric Level I trauma centers. We will collect the following outcome measures: global functioning as measured by the Pediatric Quality of Life (PedsQL) and Pediatric Glasgow Outcome Scale Extended (GOS-E Peds), working memory (digit span test), total amount of blood products transfused in the initial 48 h, intracranial hemorrhage progression at 24 h, coagulation biomarkers, and adverse events (specifically thromboembolic events and seizures).

Discussion

This multicenter trial will provide important preliminary data and assess the feasibility of conducting a confirmatory clinical trial that evaluates the benefits of TXA in children with severe trauma and hemorrhagic injuries to the torso and/or brain.

Trial registration

ClinicalTrials.gov registration number: NCT02840097 . Registered on 14 July 2016.

We examined the extracellular vesicle (EV) and RNA composition of pooled normal cerebrospinal fluid (CSF) samples and CSF from five major neurological disorders: Alzheimer's disease (AD), Parkinson's disease (PD), low-grade glioma (LGG), glioblastoma multiforme (GBM), and subarachnoid haemorrhage (SAH), representing neurodegenerative disease, cancer, and severe acute brain injury. We evaluated: (I) size and quantity of EVs by nanoparticle tracking analysis (NTA) and vesicle flow cytometry (VFC), (II) RNA yield and purity using four RNA isolation kits, (III) replication of RNA yields within and between laboratories, and (IV) composition of total and EV RNAs by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and RNA sequencing (RNASeq). The CSF contained ~106 EVs/μL by NTA and VFC. Brain tumour and SAH CSF contained more EVs and RNA relative to normal, AD, and PD. RT-qPCR and RNASeq identified disease-related populations of microRNAs and messenger RNAs (mRNAs) relative to normal CSF, in both total and EV fractions. This work presents relevant measures selected to inform the design of subsequent replicative CSF studies. The range of neurological diseases highlights variations in total and EV RNA content due to disease or collection site, revealing critical considerations guiding the selection of appropriate approaches and controls for CSF studies.

Ten ongoing studies designed to test the possibility that extracellular RNAs may serve as biomarkers in human disease are described. These studies, funded by the NIH Common Fund Extracellular RNA Communication Program, examine diverse extracellular body fluids, including plasma, serum, urine and cerebrospinal fluid. The disorders studied include hepatic and gastric cancer, cardiovascular disease, chronic kidney disease, neurodegenerative disease, brain tumours, intracranial haemorrhage, multiple sclerosis and placental disorders. Progress to date and the plans for future studies are outlined.

Background

The antifibrinolytic drug tranexamic acid (TXA) improves survival in adults with traumatic hemorrhage; however, the drug has not been evaluated in a trial in injured children. We assessed the feasibility of a large-scale trial evaluating the effects of TXA in children with severe hemorrhagic injuries.

Methods

Severely injured children (0 up to 18th birthday) were randomized into a double-blind randomized trial of (1) TXA 15 mg/kg bolus dose, followed by 2 mg/kg/h infusion over 8 h, (2) TXA 30 mg/kg bolus dose, followed by 4 mg/kg/h infusion over 8 h, or (3) normal saline placebo bolus and infusion. The trial was conducted at four pediatric Level I trauma centers in the United States between June 2018 and March 2020. We enrolled patients under federal exception from informed consent (EFIC) procedures when parents were unable to provide informed consent. Feasibility outcomes included the rate of enrollment, adherence to intervention arms, and ability to measure the primary clinical outcome. Clinical outcomes included global functioning (primary), working memory, total amount of blood products transfused, intracranial hemorrhage progression, and adverse events. The target enrollment rate was at least 1.25 patients per site per month.

Results

A total of 31 patients were randomized with a mean age of 10.7 years (standard deviation [SD] 5.0 years) and 22 (71%) patients were male. The mean time from injury to randomization was 2.4 h (SD 0.6 h). Sixteen (52%) patients had isolated brain injuries and 15 (48%) patients had isolated torso injuries. The enrollment rate using EFIC was 1.34 patients per site per month. All eligible enrolled patients received study intervention (nine patients TXA 15 mg/kg bolus dose, 10 patients TXA 30 mg/kg bolus dose, and 12 patients placebo) and had the primary outcome measured. No statistically significant differences in any of the clinical outcomes were identified.

Conclusion

Based on enrollment rate, protocol adherence, and measurement of the primary outcome in this pilot trial, we confirmed the feasibility of conducting a large-scale, randomized trial evaluating the efficacy of TXA in severely injured children with hemorrhagic brain and/or torso injuries using EFIC.

Objective

We evaluated the acceptability of the Pediatric Quality of Life Inventory (PedsQL) and other outcomes as the primary outcomes for a pediatric hemorrhagic trauma trial (TIC-TOC) among clinicians.

Methods

We conducted a mixed-methods study that included an electronic questionnaire followed by teleconference discussions. Participants confirmed or rejected the PedsQL as the primary outcome for the TIC-TOC trial and evaluated and proposed alternative primary outcomes. Responses were compiled and a list of themes and representative quotes was generated.

Results

73 of 91 (80%) participants completed the questionnaire. 61 (84%) participants agreed that the PedsQL is an appropriate primary outcome for children with hemorrhagic brain injuries. 32 (44%) participants agreed that the PedsQL is an acceptable primary outcome for children with hemorrhagic torso injuries, 27 (38%) participants were neutral, and 13 (18%) participants disagreed. Several themes were identified from responses, including that the PedsQL is an important and patient-centered outcome but may be affected by other factors, and that intracranial hemorrhage progression assessed by brain imaging (among patients with brain injuries) or blood product transfusion requirements (among patients with torso injuries) may be more objective outcomes than the PedsQL.

Conclusions

The PedsQL was a well-accepted proposed primary outcome for children with hemorrhagic brain injuries. Traumatic intracranial hemorrhage progression was favored by a subset of clinicians. A plurality of participants also considered the PedsQL an acceptable outcome for children with hemorrhagic torso injuries. Blood product transfusion requirement was favored by fewer participants.

Extracellular RNAs (exRNAs) have been identified in all tested biofluids and have been associated with a variety of extracellular vesicles, ribonucleoprotein complexes and lipoprotein complexes. Much of the interest in exRNAs lies in the fact that they may serve as signalling molecules between cells, their potential to serve as biomarkers for prediction and diagnosis of disease and the possibility that exRNAs or the extracellular particles that carry them might be used for therapeutic purposes. Among the most significant bottlenecks to progress in this field is the lack of robust and standardized methods for collection and processing of biofluids, separation of different types of exRNA-containing particles and isolation and analysis of exRNAs. The Sample and Assay Standards Working Group of the Extracellular RNA Communication Consortium is a group of laboratories funded by the U.S. National Institutes of Health to develop such methods. In our first joint endeavour, we held a series of conference calls and in-person meetings to survey the methods used among our members, placed them in the context of the current literature and used our findings to identify areas in which the identification of robust methodologies would promote rapid advancements in the exRNA field.

The Extracellular RNA Communication Consortium (ERCC) was launched to accelerate progress in the new field of extracellular RNA (exRNA) biology and to establish whether exRNAs and their carriers, including extracellular vesicles (EVs), can mediate intercellular communication and be utilized for clinical applications. Phase 1 of the ERCC focused on exRNA/EV biogenesis and function, discovery of exRNA biomarkers, development of exRNA/EV-based therapeutics, and construction of a robust set of reference exRNA profiles for a variety of biofluids. Here, we present progress by ERCC investigators in these areas, and we discuss collaborative projects directed at development of robust methods for EV/exRNA isolation and analysis and tools for sharing and computational analysis of exRNA profiling data.