Protocol and biomarker strategy for a multi-site randomized controlled trial examining biological mechanisms and dosing of active music engagement in children with acute lymphoblastic leukemia and lymphoma and parents.

BACKGROUND: Music therapy is a standard palliative care service in many pediatric and adult hospitals; however, most research has focused on the use of music to improve psychosocial dimensions of health, without considering biological dimensions. This study builds on prior work examining psychosocial mechanisms of action underlying an Active Music Engagement (AME) intervention, designed to help manage emotional distress and improve positive health outcomes in young children with cancer and parents (caregivers), by examining its effects on biomarkers of stress and immune function. METHODS: This two-group randomized controlled trial (R01NR019190) is designed to examine biological mechanisms of effect and dose-response relationships of AME on child/parent stress during the consolidation phase of Acute B- or T-cell Lymphoblastic Leukemia (ALL) and T-cell Lymphoblastic Lymphoma (TLyLy) treatment. Child/parent dyads (n = 228) are stratified (by age, site, risk level) and randomized in blocks of four to the AME or attention control condition. Each group receives one session (30-minutes AME; 20-minutes control) during weekly clinic visits (4 weeks standard risk B-cell ALL; 8 weeks high risk B-cell ALL/T-cell ALL/TLyLy). Parents complete questionnaires at baseline and post-intervention. Child/parent salivary cortisol samples are taken pre- and post-session (sessions 1-4). Child blood samples are reserved from routine draws before sessions 1 and 4 (all participants) and session 8 (high risk participants). We will use linear mixed models to estimate AME's effect on child/parent cortisol. Examining child/parent cortisol as mediators of AME effects on child and parent outcomes will be performed in an ANCOVA setting, fitting the appropriate mediation models using MPlus and then testing indirect effects using the percentile bootstrap approach. Graphical plots and non-linear repeated measures models will be used to examine dose-response relationship of AME on child/parent cortisol. DISCUSSION: During pediatric cancer treatment there are special challenges that must be considered when measuring cortisol and immune function. In this manuscript we discuss how we addressed three specific challenges through our trial design. Findings from this trial will increase mechanistic understanding of the effects of active music interventions on multiple biomarkers and understanding of dose-response effects, with direct implications for clinical practice. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04400071.

Implementing NIH Behavior Change Consortium Treatment Fidelity Recommendations in a Multi-Site Randomized Controlled Trial of an Active Music Engagement Intervention for Young Children with Cancer and Parents.

Treatment fidelity is the use of methodological strategies to monitor and enhance reliability and validity of behavioral intervention trials. Despite availability of guidelines and checklists, treatment fidelity remains underreported, hindering evaluation, interpretation, and cross-study comparisons. Treatment fidelity is particularly important for music interventions given the inherent complexity of musical stimuli and flexibility required for tailored delivery. The purpose of this paper is to define and describe treatment fidelity strategies for our trial of a music-based play intervention for young children with cancer and parents grounded in the NIH Behavior Change Consortium Treatment Fidelity Recommendations. We report strategies for all 5 areas: study design, training providers, delivery of treatment, receipt of treatment, and enactment of treatment skills. We also discuss 4 challenges our team encountered, including: (1) standardizing live music delivery, (2) defining boundaries for tailored intervention delivery, (3) managing extended time between participants, and (4) minimizing risk for bias. This paper expands on current fidelity literature and may provide a working model for other investigators examining dyadic and/or active music interventions.

Development of a carotid artery thrombolysis stroke model in mice.

Recanalization with restored cerebral perfusion is the primary goal of thrombolytic therapy in acute ischemic stroke. The identification of adjunctive therapies that can be safely used to enhance thrombolysis in stroke remains an elusive goal. We report here the development of a mouse in situ carotid artery thrombolysis (iCAT) stroke model involving graded cerebral ischemia to induce unihemispheric infarction after thrombotic occlusion of the common carotid artery (CCA). Electrolytic-induced thrombotic occlusion of the left CCA enabled real-time assessment of recanalization and rethrombosis events after thrombolysis with recombinant tissue-type plasminogen activator (rtPA). Concurrent transient stenosis of the right CCA induced unihemispheric hypoperfusion and infarction in the left middle cerebral artery territory. Real-time assessment of thrombolysis revealed recanalization rates <30% in rtPA-treated animals with high rates of rethrombosis. Addition of the direct thrombin inhibitor argatroban increased recanalization rates to 50% and reduced rethrombosis. Paradoxically, this was associated with increased cerebral ischemia and stroke-related mortality (25%-42%). Serial analysis of carotid and cerebral blood flow showed that coadministration of argatroban with rtPA resulted in a marked increase in carotid artery embolization, leading to distal obstruction of the middle cerebral artery. Real-time imaging of carotid thrombi revealed that adjunctive anticoagulation destabilized platelet-rich thrombi at the vessel wall, leading to dislodgement of large platelet emboli. These studies confirm the benefits of anticoagulants in enhancing thrombolysis and large artery recanalization; however, at high levels of anticoagulation (∼3-fold prolongation of activated partial thromboplastin time), this effect is offset by increased incidence of carotid artery embolization and distal middle cerebral artery occlusion. The iCAT stroke model should provide important new insight into the effects of adjunctive antithrombotic agents on real-time thrombus dynamics during thrombolysis and their correlation with stroke outcomes.

Endogenous fibrinolysis facilitates clot retraction in vivo.

Clot retraction refers to the process whereby activated platelets transduce contractile forces onto the fibrin network of a thrombus, which over time increases clot density and decreases clot size. This process is considered important for promoting clot stability and maintaining blood vessel patency. Insights into the mechanisms regulating clot retraction at sites of vascular injury have been hampered by a paucity of in vivo experimental models. By pairing localized vascular injury with thrombin microinjection in the mesenteric circulation of mice, we have demonstrated that the fibrin network of thrombi progressively compacts over a 2-hour period. This was a genuine retraction process, as treating thrombi with blebbistatin to inhibit myosin IIa-mediated platelet contractility prevented shrinkage of the fibrin network. Real-time confocal analysis of fibrinolysis after recombinant tissue-type plasminogen activator (tPA) administration revealed that incomplete proteolysis of fibrin polymers markedly facilitated clot retraction. Similarly, inhibiting endogenous fibrinolysis with tranexamic acid reduced retraction of fibrin polymers in vivo. In vitro clot retraction experiments indicated that subthreshold doses of tPA facilitated clot retraction through a plasmin-dependent mechanism. These effects correlated with changes in the elastic modulus of fibrin clots. These findings define the endogenous fibrinolytic system as an important regulator of clot retraction, and show that promoting clot retraction is a novel and complementary means by which fibrinolytic enzymes can reduce thrombus size.