Circulating Extracellular Mitochondria in Cardiometabolic Disease: Harnessing the Potential for Diagnosis, Prognosis, and Treatment

Mitochondria play a significant role in the functioning of the cell, acting both as an intracellular energy source and a signaling organelle. In the heart, mitochondria produce more than 95% of the ATP in addition to regulating the redox state, calcium homeostasis, apoptosis, and lipid synthesis. However, there is also evidence that mitochondria exist outside of cells where they have been observed to mediate cell-to-cell communication, repair, and participate in the immune response. Cardiometabolic disease (CMD) has a complex pathogenesis closely associated with mitochondrial dysregulation, inflammation, and metabolic abnormalities. Because of this metabolic interdependence between the myocardium and the intracellular mitochondria, circulating extracellular mitochondria (CEMI) are being identified as possible regulators of CMD. Outside of the cell, mitochondrial functions are determined by the mitochondrial form, either as whole functional structures (e.g., small extracellular mitochondria) or as mitochondrial components with or without membrane encapsulation. Here, we explore the different forms of CEMI, their role in CMD pathogenesis, their potential therapeutic utility in treating diseases, and their role as biomarkers.