Effect of beta-alanine supplementation on muscle carnosine, oxidative and carbonyl stress, antioxidants and physical capacity in patients with COPD

Abstract

<b>Background:</b> Beta-alanine (BA) supplementation increases muscle carnosine (mCAR), an endogenous antioxidant and pH-buffer. It may be a strategy to enhance exercise capacity in patients with COPD as they suffer from elevated exercise-induced muscle oxidative stress and acidosis. We investigated whether BA supplementation increases mCAR and induces change in oxidative/carbonyl stress, antioxidants and physical capacity in patients with COPD. <b>Methods:</b> In a double blind, placebo(PL)-controlled, randomized trial, 40 patients (65±6 y; 75% male; 55±14 FEV₁%pred) were assigned to 12 weeks oral BA or PL. Biopsy of m. vastus lateralis was obtained pre/post intervention and mCAR, proteins affected by carbonylation and 4-hydroxynonenal, and mRNA expression of antioxidants were quantified. Incremental and constant work-rate cycle capacity, and quadriceps strength and endurance were assessed. Linear mixed model analysis was performed. <b>Results:</b> BA supplementation increased mCAR and reduced mRNA expression of glutathione peroxidase 4 (GPX4) vs. PL, while oxidative/carbonyl stress, other antioxidants and physical capacity did not change (Table 1). <b>Conclusion:</b> BA supplementation augments mCAR with 54% of baseline values in patients with COPD, which seems to downregulate antioxidant GPX4, but not beneficially change oxidative/carbonyl stress, other antioxidants and physical capacity.