Mitochondrial transfer: a Janus-faced force in health and disease.

Mitochondrial transfer is increasingly recognized as a dynamic form of intercellular communication that reshapes how we understand tissue homeostasis, immune function, and disease progression. Rather than being a passive event, mitochondrial transfer involves the movement of organelles between cells through defined mechanisms, such as tunneling nanotubes, extracellular vesicles, or direct engulfment, altering the metabolic, epigenetic, and immunological profiles of recipient cells. In physiological and regenerative contexts, mitochondrial transfer contributes to cellular rescue, stem cell function, and organ recovery. However, in malignancies and infections, it can subvert immune surveillance, promote metabolic reprogramming, and reinforce pathological resilience. This dual capacity - simultaneously protective and pathogenic - positions mitochondrial transfer as a central yet ambivalent mechanism in health and disease. Beyond mechanistic insight, we explore its implications for emerging mitochondrial therapies, highlighting critical considerations in donor-recipient compatibility, organelle identity, and translational ethics. Mitochondrial transfer is increasingly recognized as a biologically significant process with both therapeutic potential and complex implications for our understanding of intercellular communication.