NAD in skeletal muscle at 3 T: impact of age and disease

Motivation: NAD is a metabolite of interest in the investigation of muscle with aging and disease; and it can be measured using 31P MRS. Goal(s): We aimed to quantify NAD in two different muscle groups in a cohort of healthy controls and in patients with a known muscle disease, at 3 T. Approach: Besides assessing total NAD concentrations, we attempted to quantify both NAD+ and NADH following simulations to assess the robustness to separate both resonances on a 3-T clinical system. Results: Total NAD correlated negatively with age, demonstrated differences between muscles and decreased with disease; while robust separation between NAD+-NADH remained challenging. Impact: Since NAD is abundant in living cells and sensitive to change (age, disease, exercise, supplementation) and 31P MRS allows its quantification, this metabolite can serve as a potential quantitative MR biomarker in skeletal muscle studies.