Cardiac failure in adults is associated with down regulation of fatty acid beta oxidation and accumulation of long chain (LC) fatty acid derivatives such as LC acylcarnitines [1Sack M.N., Rader T.A., Park S., Bastin J., McCune S.A., Kelly D.P., et al. Fatty acid oxidation enzyme gene expression is downregulated in the failing heart Circulation 1996 ; 2837-2842 [cross-ref]

Cliquez ici pour aller à la section Références, 2Ruiz M., Labarthe F., Fortier A., Bouchard B., Thompson Legault J., Bolduc V., et al. Circulating acylcarnitine profile in human heart failure: a surrogate of fatty acid metabolic dysregulation in mitochondria and beyond Am J Physiol Heart Circ Physiol 2017 ; H768-H781

Cliquez ici pour aller à la section Références]. These lipidomic disturbances have been shown to impair cardiac function [3D'Souza K.Nzirorera C., Kienesberger P.C., D'Souza K. Lipid metabolism and signaling in cardiac lipotoxicity Biochim Biophys Acta 2016 ; 1513-1524 [cross-ref]

Cliquez ici pour aller à la section Références]. No data are available concerning metabolic modification in heart failure in children.

We retrospectively collected acylcarnitines profiles, NT pro BNP, clinical and echographical data and MRI performed in children explored for a non-metabolic cardiomyopathy in our centre from 2015 to 2021.

Eighteen children aged from 1 month to 16years old (median 2.7years old) met the inclusion criteria. Thirteen were diagnosed for a dilated cardiomyopathy (DCM) [with normal left ventricular ejection fraction (LVEF) for 5 of them], 4 had a hypertrophic cardiomyopathy and 1 suffered from a restrictive cardiomyopathy. Seven children had clinical symptoms of cardiac insufficiency, and nine showed elevation of NT pro BNP. Considering first only children with DCM, sum of total acylcarnitines and sum of LC acylcarnitines were significantly enhanced in patients with impaired LVEF compared to those with normal LVEF (40.0±16.8 vs. 16.2±5.7μM, P<0.01, and 4.8±1.6 vs. 3.1±0.7μM, P<0.05, respectively). Similarly, considering the whole patients with cardiomyopathy, children with an elevation of NT pro BNP level displayed accumulation of total acylcarnitines and LC acylcarnitines compared to those with a normal NT pro BNP level (38.9±16.9 vs. 15.5±8.2μM, P<0.01, and 5.2±2.4 vs. 2.8±1.1μM, P<0.01, respectively).

Our results suggest alteration of fatty acid oxidation in children with cardiomyopathy and impaired LVEF or elevated NT pro BNP. This metabolic modification needs to be confirmed with a larger scale study. Such lipidomic alteration could worsen heart function, and may suggest considering a metabolic treatment of heart failure in children.