Motivational Enhancement Interventions to Increase Pre-Exposure Prophylaxis Use in Sexual Minority Men Who Use Stimulants: Protocol for a Pilot Sequential Multiple Assignment Randomized Trial.

BACKGROUND: Although pre-exposure prophylaxis (PrEP) could substantially mitigate HIV risk, sexual minority men who use stimulants commonly experience difficulties with engaging in PrEP clinical services. Motivational interviewing (MI) and contingency management (CM) reduce substance use and condomless anal sex (CAS) in this population, but these motivational enhancement interventions require modifications to promote engagement along the PrEP care continuum. OBJECTIVE: PrEP Readiness Interventions for Supporting Motivation (PRISM) is a pilot sequential multiple assignment randomized trial testing the feasibility, acceptability, and preliminary effectiveness of distinct combinations of telehealth MI and CM in 70 cisgender sexual minority men who use stimulants that are not currently taking PrEP. METHODS: A national sample was recruited via social networking applications to complete a baseline assessment and mail-in HIV testing. Those with nonreactive HIV results were randomized to receive either (1) a 2-session MI intervention focusing on PrEP use (session 1) and concomitant stimulant use or CAS (session 2) or (2) a CM intervention with financial incentives for documented evidence of PrEP clinical evaluation by a medical provider (US $50) and filling a PrEP prescription (US $50). At the 3-month follow-up assessment, participants who reported they had not filled a prescription for PrEP were randomized a second time to either (1) switch to a second-stage intervention (ie, MI+CM or CM+MI) or (2) continue with assessments only. Outcomes for both responders and nonresponders were reassessed at a 6-month follow-up. The primary outcome is documented evidence of filling a PrEP prescription over 6 months. Self-reported secondary outcomes include PrEP clinical evaluation by a medical provider, stimulant use, and CAS. Qualitative exit interviews were conducted with a subgroup of responders and nonresponders to characterize their experiences with the MI and CM interventions. RESULTS: Implementation of PRISM underscores challenges in reaching sexual minority men who use stimulants to optimize HIV prevention efforts. Approximately 1 in 10 (104/1060) eligible participants have enrolled. Of the 104 who enrolled, 87 (84%) completed mail-in HIV testing. We delivered 5 preliminary HIV-positive results, including posttest counseling with referrals to confirmatory testing. CONCLUSIONS: Lessons learned from PRISM underscore the central importance of a flexible, participant-centered approach to support the engagement of sexual minority men who use stimulants. Leveraging telehealth platforms to deliver motivational enhancement interventions also expanded their reach and potential public health impact with this high-priority population. Further research is needed to determine the effectiveness of telehealth MI and CM for supporting PrEP use in sexual minority men who use stimulants. TRIAL REGISTRATION: ClinicalTrials.gov NCT04205487; https://clinicaltrials.gov/study/NCT04205487. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/48459.

Frataxin deficiency impairs mitochondrial biogenesis in cells, mice and humans.

Friedreich's ataxia (FRDA) is a neurodegenerative disease caused by inherited deficiency of the mitochondrial protein Frataxin (FXN), which has no approved therapy and is an area in which biomarkers are needed for clinical development. Here, we investigated the consequences of FXN deficiency in patient-derived FRDA fibroblast cell models, the FRDA mouse model KIKO, and in whole blood collected from patients with FRDA. We observed decreased mitochondrial copy number in all the three FRDA models tested: cells, mice and patient blood. In addition, we observed 40% residual mitochondrial gene expression in FRDA patient blood. These deficiencies of mitochondrial biogenesis in FRDA cells and patient blood are significantly correlated with FXN expression, consistent with the idea that the decreased mitochondrial biogenesis is a consequence of FXN deficiency. The observations appear relevant to the FRDA pathophysiological mechanism, as FXN-dependent deficiency in mitochondrial biogenesis and consequent mitochondrial bioenergetic defect could contribute to the neurodegenerative process. The observations may also have translational potential, as mitochondrial biogenesis could now be followed as a clinical biomarker of FRDA as a correlate of disease severity, progression, and therapeutic effect. Also, mitochondrial copy number in blood is objective, scalar and more investigator-independent than clinical-neurological patient rating scales. Thus, FXN deficiency causes mitochondrial deficiency in FRDA cells, the KIKO mouse model, and in whole blood of patients with FRDA, and this deficiency could potentially be used in clinical trial design.

Neurobehavioral deficits in the KIKO mouse model of Friedreich's ataxia.

Friedreich's Ataxia (FA) is a pediatric neurodegenerative disease whose clinical presentation includes ataxia, muscle weakness, and peripheral sensory neuropathy. The KIKO mouse is an animal model of FA with frataxin deficiency first described in 2002, but neurobehavioral deficits have never been described in this model. The identification of robust neurobehavioral deficits in KIKO mice could support the testing of drugs for FA, which currently has no approved therapy. We tested 13 neurobehavioral tasks to identify a robust KIKO phenotype: Open Field, Grip Strength Test(s), Cylinder, Skilled Forelimb Grasp Task(s), Treadmill Endurance, Locotronic Motor Coordination, Inverted Screen, Treadscan, and Von Frey. Of these, Inverted Screen, Treadscan and Von Frey produced significant neurobehavioral deficits at >8 months of age, and relate to the clinically relevant endpoints of muscle strength and endurance, gait ataxia, and peripheral insensitivity. Thus we identify robust phenotypic measures related to Friedreich's ataxia clinical endpoints which could be used to test effectiveness of potential drug therapy.

Effect of cardiac pacing on forearm vascular responses and nitric oxide function.

We examined the hypothesis that changes in heart rate at rest influence bioactivity of nitric oxide (NO) in humans by examining forearm blood flow responses during cardiac pacing in six subjects. Peak forearm and mean forearm blood flows across the cardiac cycle were continuously recorded at baseline and during pacing, with the use of high-resolution brachial artery ultrasound and Doppler flow velocity measurement. The brachial artery was cannulated to allow continuous infusion of saline or N(G)-monomethyl-L-arginine (L-NMMA). As heart rate increased, no changes in pulse pressure and mean or peak blood flow were evident. L-NMMA had no effect on brachial artery diameter, velocity, or flows compared with saline infusion. These results contrast with our recent findings that exercise involving the lower body, associated with increases in heart rate and pulse pressure, also increased forearm blood flow, the latter response being diminished by L-NMMA. These data suggest that changes in blood pressure, rather than pulse frequency, may be the stimulus for shear stress-mediated NO release in vivo.