Insulin Sensitivity and Insulin Secretion in Adults With Friedreich's Ataxia: The Role of Skeletal Muscle.

Introduction: Friedreich's ataxia (FRDA) is a multisystem disorder caused by frataxin deficiency. FRDA-related diabetes mellitus (DM) is common. Frataxin supports skeletal muscle mitochondrial oxidative phosphorylation (OXPHOS) capacity, a mediator of insulin sensitivity.

In vivo assessment of OXPHOS capacity using 3 T CrCEST MRI in Friedreich's ataxia.

Background: Friedreich's ataxia (FRDA) is a neurodegenerative disease caused by decreased expression of frataxin, a protein involved in many cellular metabolic processes, including mitochondrial oxidative phosphorylation (OXPHOS). Our objective was to assess skeletal muscle oxidative metabolism in vivo in adults with FRDA as compared to adults without FRDA using chemical exchange saturation transfer (CrCEST) MRI, which measures free creatine (Cr) over time following an in-magnet plantar flexion exercise.

Methods: Participants included adults with FRDA (n = 11) and healthy adults (n = 25).

Multimodality assessment of heart failure with preserved ejection fraction skeletal muscle reveals differences in the machinery of energy fuel metabolism.

Aims: Skeletal muscle (SkM) abnormalities may impact exercise capacity in patients with heart failure with preserved ejection fraction (HFpEF). We sought to quantify differences in SkM oxidative phosphorylation capacity (OxPhos), fibre composition, and the SkM proteome between HFpEF, hypertensive (HTN), and healthy participants.

Methods And Results: Fifty-nine subjects (20 healthy, 19 HTN, and 20 HFpEF) performed a maximal-effort cardiopulmonary exercise test to define peak oxygen consumption (VO ), ventilatory threshold (VT), and VO efficiency (ratio of total work performed to O consumed).