Mitochondrial transfer and mesenchymal stem cells in ophthalmology: current evidence and therapeutic implications.

Mitochondrial dysfunction, driven by genetic mutations or oxidative stress, is a central contributor to the onset and progression of ophthalmic diseases. In recent years, intercellular mitochondrial transfer (MT) has emerged as a novel mechanism of cellular communication and repair in ocular tissues. MT occurs through tunneling nanotubes, extracellular vesicles (EVs), cell fusion, or transmitophagy, and has been shown to support photoreceptor survival, maintain retinal homeostasis, and protect against oxidative injury. Mesenchymal stem cells (MSCs), owing to their remarkable reparative and immunomodulatory properties, have attracted particular attention as efficient mitochondrial donors. Evidence from experimental models demonstrates that MSC-mediated MT can restore bioenergetics, mitigate oxidative stress, and rescue cellular function in inherited optic neuropathies, corneal injuries, retinal degenerative diseases, and ischemic retinopathies. This review summarizes current evidence of MT in ophthalmology, highlights the therapeutic contributions of MSCs, discusses the molecular and microenvironmental factors regulating MT efficiency, and outlines unresolved challenges. We further provide perspectives on how mitochondrial transfer may be translated into innovative therapies for ocular disorders.