ABSTRACT
Introduction: The cytochrome P450 enzyme subfamilies, including CYP3A4 and CYP1A2, have a major role in metabolism of a range of drugs including several anti-cancer treatments. Many factors including environmental exposures, diet, diseaserelated systemic inflammation and certain genetic polymorphisms can impact the activity level of these enzymes. As a result, the net activity of each enzyme subfamily can vary widely between individuals and in the same individual over time. This variability has potential major implications for treatment efficacy and risk of drug toxicity, but currently no assays are available for routine use to guide clinical decision-making. Methods: To address this, a mass spectrometry-based method to measure activities of CYP3A4, CYP1A2 was adapted and tested in free-living participants. The assay results were compared with the predicted activity of each enzyme, based on a self-report tool capturing diet, medication, chronic disease state, and tobacco usage. In addition, a feasibility test was performed using a low-volume dried blood spots (DBS) on two different filter-paper supports, to determine if the same assay could be deployed without the need for repeated standard blood tests. Results: The results confirmed the methodology is safe and feasible to perform in free-living participants using midazolam and caffeine as test substrates for CYP3A4 and CYP1A2 respectively. Furthermore, though similar methods were previously shown to be compatible with the DBS format, the assay can also be performed successfully while incorporating glucuronidase treatment into the DBS approach. The measured CYP3A4 activity score varied 2.6-fold across participants and correlated with predicted activity score obtained with the self-report tool. The measured CYP1A2 activity varied 3.5-fold between participants but no correlation with predicted activity from the self-report tool was found. Discussion: The results confirm the wide variation in CYP activity between individuals and the important role of diet and other exposures in determining CYP3A4 activity. This methodology shows great potential and future cross-sectional and longitudinal studies using DBS are warranted to determine how best to use the assay results to guide drug treatments.
ABSTRACT
BACKGROUND: Emotion regulation is an ability related to psychological well-being; when dysregulated, individuals may have psychiatric symptoms and maladapted physiological responses. Virtual reality-assisted cognitive behavioral therapy (VR-CBT) is an effective psychotherapy to target and strengthen emotion regulation; however, it currently lacks cultural sensitivity and can be improved by adapting it to the cultural context of service users. During previous participatory research, we co-designed a culturally adapted cognitive behavioral therapy (CBT) manual and 2 virtual reality (VR) environments to function as a complement to therapy (VR-CBT) for Inuit who would like to access psychotherapy. Emotion regulation skill building will occur in virtual environments that have interactive components such as heart rate biofeedback. OBJECTIVE: We describe a protocol for a proof-of-concept 2-arm randomized controlled trial (RCT) with Inuit (n=40) in Québec. The primary aims of this research are to investigate the feasibility, benefits, and challenges of the culturally adapted VR-CBT intervention versus an established VR self-management that is available commercially. We will also investigate self-rated mental well-being and objective psychophysiological measures. Finally, we will use proof-of-concept data to identify suitable primary outcome measures, conduct power calculations in a larger trial for efficacy, and collect information about preferences for on-site or at-home treatment. METHODS: Trial participants will be randomly assigned to an active condition or active control condition in a 1:1 ratio. Inuit aged 14 to 60 years will receive a culturally adapted and therapist-guided VR-CBT with biofeedback or a VR relaxation program with nonpersonalized guided components over a 10-week period. We will collect pre- and posttreatment measures of emotion regulation and biweekly assessments over the treatment and at 3-month follow-up. The primary outcome will be measured by the Difficulties in Emotion Regulation Scale (DERS-16) and a novel psychophysiological reactivity paradigm. Secondary measures include psychological symptoms and well-being via rating scales (eg, anxiety or depressive symptoms). RESULTS: As this is the prospective registration of an RCT protocol, we do not yet report any results from the trial. Funding was confirmed in January 2020, and recruitment is expected to start in March 2023 and is set to finish in August 2025. The expected results are to be published in spring 2026. CONCLUSIONS: The proposed study responds to the community's desire for accessible and appropriate resources for psychological well-being, as it was developed in active collaboration with the Inuit community in Québec. We will test feasibility and acceptance by comparing a culturally adapted, on-site psychotherapy with a commercial self-management program while incorporating novel technology and measurement in the area of Indigenous health. We also aim to fulfill the needs for RCT evidence of culturally adapted psychotherapies that are lacking in Canada. TRIAL REGISTRATION: International Standard Randomized Controlled Trial Number (ISRCTN) 21831510; https://www.isrctn.com/ISRCTN21831510. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/40236.
