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Impaired dynein function preserves spinal interneuron survival and positioning in an ALS-like mouse model

by Eleni Christoforidou, Jordan S. Rowe, Fabio A. Simoes, Raphaelle Cassel, Luc Dupuis, Peter Nigel Leigh, Majid Hafezparast

Impaired cytoplasmic dynein function has been implicated in amyotrophic lateral sclerosis (ALS) pathogenesis, yet the contributions of spinal interneurons to disease phenotypes remain unclear. We tested the hypothesis that hypomorphic dynein function in cholinergic neurons disrupts the development, survival, or positioning of inhibitory interneuron populations in the lumbar spinal cord. Using ChAT-Cre recombination, we generated four mouse genotypes with graded reductions in dynein activity in ChAT+ cells: Dync1h1+/+ (wildtype), Dync1h1−/+ (hemizygous wildtype), Dync1h1+/Loa (heterozygous Loa mutation), and Dync1h1−/Loa (hemizygous Loa). At 52 weeks of age, lumbar spinal cords (L3–L6) were harvested, cryosectioned, and immunostained for ChAT, GAD-67, Parvalbumin, and Calbindin. Cell counts were performed on confocal images from eight sections per mouse (N = 3 male mice/genotype), and radial distances from the central canal were normalised to gray matter width. Angular distributions were analysed via circular statistics. There were no significant genotype-dependent differences in the numbers of ChAT+, GAD-67+, Parvalbumin+, or Calbindin+ cells, nor in ChAT+ subpopulations (motor neurons versus interneurons) or double‐positive interneuron subsets (e.g., ChAT+–GAD-67+, Parvalbumin+–GAD-67+, Parvalbumin+–Calbindin+). Radial positioning relative to the central canal was similarly preserved across all markers and genotypes. Circular‐median tests revealed statistically significant shifts in mean angle for ChAT+, GAD-67+, and certain double‐positive cells, but these amounted to only 5–10° displacements, translating to lateral shifts of ~10–20 µm, well within single laminar bands, and are unlikely to impact circuit connectivity. Despite substantial motor deficits and hallmark TDP-43 pathology previously seen in these models, impaired dynein function does not precipitate interneuron loss or gross migratory defects in the lumbar spinal cord. Instead, our findings suggest that the primary contributions of dynein to ALS-like phenotypes likely arise from functional disruptions in axonal transport, synaptic maintenance, and neuronal physiology rather than from structural alterations or loss of interneuron populations.

Comparison of intention-to-treat and per-protocol results in non-inferiority trials: a methodological review protocol

Por: Parpia · S. · Ofori · S. · McKechnie · T. · Rajan · N. · Wang · Y. · Wang · B. · Guyatt · G.
Introduction

Non-inferiority (NI) trial designs, which assess whether an experimental intervention is no worse than the standard of care, have become increasingly prevalent in recent years. Current thinking suggests that the intention-to-treat (ITT) analysis is considered anti-conservative in the presence of protocol violations when compared with the per-protocol (PP) analysis.

Methods and analysis

We aim to conduct a methodological review of NI trials to compare the results from ITT and PP analysis in NI trials. A comprehensive electronic search strategy will be used to identify studies indexed in MEDLINE, Embase and Cochrane Central Register of Controlled Trials databases. We will include 390 NI trials published prior to 31 December 2024. The primary outcomes are the treatment effect estimates from ITT and PP analyses. Secondary outcomes are the CI widths and the bounds of the CIs from the ITT and PP analyses. Analysis will calculate the relative difference in the point estimates, CI widths and CI bounds between the two approaches. Linear models will be used to investigate the relationship between the outcomes and the proportion of patients excluded from the PP analysis.

Ethics and dissemination

This is a methodological review that has been registered on the International Prospective Register for Systematic Reviews (PROSPERO, CRD420251125360). Research ethics is not required as the project is a methodological review of previously published trials. Study findings will be shared via peer-reviewed publications and presentations at academic conferences.

Scale-up of a paediatric HIV disclosure intervention in Ghana using a stepped wedge cluster randomised trial design: Sankofa 2 protocol and implementation

Por: Reynolds · N. R. · Shabanova · V. · Renner · L. · Antwi · S. · Ayisi Addo · S. · Enimil · A. K. · Lartey · M. · Gan · G. · Parziale · S. · Aikins Amissah · K. · Kusah · J. T. · Ofori-Atta · A. L. · Slade · E. · Agyarko-Poku · T. · Paintsil · E.
Introduction

There is a pressing need for effective interventions that can support healthcare workers and caregivers in the challenging yet crucial task of disclosing the HIV status to infected children and adolescents. Previously, we developed and tested a successful disclosure intervention called Sankofa in Ghana. In an ongoing 5-year follow-up study, Sankofa 2, we aim to build on the successful Sankofa trial by testing the intervention on a larger scale.

Methods and analysis

This study is a pragmatic, stepped-wedge cluster randomised trial.

Setting

It is being conducted in 12 HIV paediatric clinics in Ghana to examine the effectiveness, health benefits, cost and implementation of the Sankofa intervention. Caregiver–child dyads (n=700) will be enrolled. Evaluation of effectiveness, health benefits, cost and implementation of the Paediatric HIV disclosure intervention, Sankofa 2, is posed to offer valuable insights for scale-up and sustainability.

Ethics and dissemination

Ethical clearance has been obtained from the Ghana Health Service Ethics Review Committee, the University of Ghana Ethical and Protocol Review Committee, the Committee on Human Research Publication and Ethics of the Kwame Nkrumah University of Science and Technology, the Johns Hopkins Medicine Institutional Review Board and the Yale School of Medicine Human Investigation Committee. The clinical trial was registered on ClinicalTrials.gov on 5 March 2021. All caregiver participants are required to provide written informed consent and the children assent before enrolment. If either the child or caregiver says no to the study, the dyad is not eligible for the study. No study-related procedures are performed until consent is obtained. The results of the trial will be added on ClinicalTrials.gov, published in peer-reviewed journals and presented at international conferences.

Trial registration number

NCT04791865.

Enhancing cognitive function in breast cancer survivors through community-based aerobic exercise training: protocol for a Hybrid Type I effectiveness-implementation study employing a randomised controlled design

Por: Ehlers · D. K. · Austin · J. D. · Ernst · B. · Page · L. L. · Ofori · E. · Porter · G. C. · Fanning · J. · Hickman · G. · McKim · P. · Cole · M. · Donaldson · M. · Braden · B. B. · Kunze · K. L. · Butterfield · R. J. · Baxter · L. C. · Ahles · T. A. · Estabrooks · P.
Introduction

Despite growing evidence to characterise cancer-associated cognitive decline (CACD) in women with breast cancer, interventions to mitigate CACD are limited. Emerging evidence suggests aerobic exercise may enhance cognition after breast cancer diagnosis and treatment; yet, CACD remains an understudied outcome of exercise, and few high-quality studies have been conducted. In addition to knowledge gaps in effectiveness, the translation of exercise interventions to community settings remains challenging. The Breast cancer Reasoning and Activity INtervention (BRAIN) investigates the effectiveness of aerobic exercise training, delivered in a community-based setting, for improving cognitive function in women with breast cancer and gathers information on the implementation success of the intervention.

Methods and analysis

This Hybrid Type I effectiveness–implementation study is conducted at an academic medical centre in the southwestern United States in partnership with a non-profit, community health and wellness organisation. The study enrols 160 women diagnosed with stage I–IIIa breast cancer and within 3–36 months of treatment completion into a 1:1 randomised controlled trial. Individuals randomised to the exercise group receive a 6-month, individually tailored aerobic exercise programme delivered by exercise trainers employed at local community fitness centres. The programme is progressive in nature and designed to help participants achieve aerobic exercise levels consistent with guidelines for cancer survivors. Individuals randomise to the control group receive a 6-month health education control intervention delivered virtually by hospital-based health educators. Cognitive performance (primary), self-reported cognition, patient-reported outcomes, physical activity and cardiorespiratory fitness are measured at baseline, 6 months (postintervention) and 12 months (follow-up). Brain structure and function are measured via magnetic resonance imaging (MRI) at baseline and 6 months. Implementation outcomes are defined by the RE-AIM framework, which includes reach, effectiveness, adoption, implementation and maintenance. RE-AIM outcomes are measured at baseline, 6 months, 12 months and ongoing during the study.

Ethics and dissemination

This study was approved by the Mayo Clinic Institutional Review Board (#23-000020). All participants provide informed consent prior to participation. Findings will be disseminated to scientific, clinical and community audiences through manuscripts, presentations and newsletters.

Trial registration number

NCT04816006.

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