Mitochondrial Transfer: From Bench to Bedside

Intercellular mitochondrial transfer has emerged as a fundamental mechanism of tissue adaptation and repair in the cardiovascular system, with major implications for cardiovascular, neurological, metabolic, and inflammatory diseases. Once thought to be static, mitochondria are now recognized as mobile organelles that move between cells via tunneling nanotubes, extracellular vesicles, and free mitochondria. These pathways support 2 complementary axes of mitochondrial communication: Rescue by Replenish, in which healthy mitochondria or mitochondrial components restore bioenergetics and stress resistance in recipient cells, and Relief by Release, in which damaged mitochondria are exported for degradation to preserve homeostasis and limit inflammation. We summarize the molecular machinery governing tunneling nanotube formation, mitochondria-derived vesicle biogenesis, extracellular vesicle sorting, and free mitochondrial release and uptake, and discuss how these processes shape organ function. Building on these mechanistic insights, we outline 4 translational strategies: (1) cell-based therapies that donate healthy mitochondria or scavenge damaged ones; cell-free approaches using (2) mitochondria-containing extracellular vesicles or (3) purified mitochondria; (4) pharmacological, nutritional, and lifestyle interventions that augment endogenous mitochondrial turnover and intercellular exchange. Finally, we discuss key barriers to clinical translation, including inflammatory and oncogenic risks, mitonuclear incompatibility, incomplete understanding of the fate and durability of transferred mitochondria, and the lack of standardized manufacturing, potency assays, and long-term storage methods. Continued integration of mechanistic biology with bioengineering and regulatory science will be essential to safely move mitochondrial transfer-based therapies from bench to bedside in cardiovascular medicine.