Integrated metabolomic profiling reveals metabolomic responses by epicardial and myocardial stromal cells to ischemia.

Abstract

Introduction: Cardiac ischemia induces substantial metabolomic reprogramming, which dysregulates cardiomyocytes (CMs) and non-myocyte stromal cell populations. The stromal cells derived from epicardial adipose tissue (EAT) and ventricle are critical for extracellular matrix (ECM) remodeling, paracrine signaling, and myocardial homeostasis. However, the metabolomic content and responses of EAT-derived stromal cells (EATDS) and ventricular stromal cells (VSCs) remain unknown.

Methodology: This study employed untargeted liquid chromatography-mass spectrometry (LC-MS)-based metabolomics to characterize ischemia-driven metabolic reprogramming in EATDS and VSCs harvested from swine hearts. Ischemia was simulated using the standard ischemic buffer (pH 6.2) for 2 h.

Results: Metabolomic screening revealed 65 and 68 metabolites, respectively, for EATDS and VSCs. Results revealed extensive downregulation of amino acid biosynthesis, redox pathways, and mitochondrial metabolism, alongside selective upregulation of glycolytic and cofactor-associated metabolites. Pathway enrichment analyses indicated significant suppression of the TCA cycle, one-carbon metabolism, glutathione cycling, and branched-chain amino acid degradation, reflecting impaired bioenergetic and antioxidant capacity. Adaptive responses included the enrichment of glycolysis, β-alanine, and glyoxylate/dicarboxylate metabolism, consistent with metabolic plasticity under hypoxic conditions. Network-based analyses linked these metabolic shifts to inflammatory pathways. Functional assays demonstrated that sarcosine, pyroglutamic acid, and 3-hydroxypropionic acid modulate the gene expression of cardiac regenerative biomarkers, including GATA4, Nkx2.5, TROP-I, LGALS1, TBX5, and IRX4.

Conclusions: These findings suggest that ischemia-induced metabolomic changes exert transcriptional control over cardiac remodeling programs, emphasizing the regulatory potential of metabolite-gene interactions. Such an integrated metabolomic transcriptional response highlights novel therapeutic targets for modulating cellular resilience and heart regeneration following ischemic heart disease.