Ketogenic diet induces cardiac changes via the OHB-Ffar3-Hopx/ACTC1 regulatory pathway in growing mice

Abstract

The ketogenic diet (KD), a high-fat, low-carbohydrate dietary regimen widely used for drug-resistant epilepsy and weight management, has been increasingly applied in adolescents. However, its long-term effects on juvenile cardiac development and functional homeostasis remain poorly understood. Here, juvenile mice (postnatal day 28–84) were fed a KD, and the underlying mechanisms were further investigated in β-hydroxybutyrate (OHB)-treated H9C2 cardiomyocytes. KD induced sustained ketosis, reduced body weight gain, and promoted a smaller cardiac phenotype accompanied by progressive alterations in ventricular functional parameters, including decreased LVEF/LVFS, septal thinning, and elevated BNP levels. Histological analyses revealed myocardial disorganization, myofibrillar disruption, mitochondrial abnormalities, and reduced cardiomyocyte area, together with decreased expression of proteins involved in cardiac contraction and calcium handling. Transcriptomic analysis identified Hopx as a key downregulated gene. Mechanistically, OHB exposure was associated with increased Ffar3 expression and reduced Hopx expression, while HOPX was found to interact with ACTC1. Hopx silencing recapitulated the OHB-induced alterations, whereas Hopx overexpression partially alleviated these effects. Collectively, long-term KD/OHB exposure impairs juvenile cardiac development and functional homeostasis through a candidate OHB-Ffar3-Hopx/ACTC1 regulatory pathway, highlighting potential cardiac risks associated with prolonged KD exposure during postnatal development.