Scientists injected a patient's own mitochondria into her eyes in an experimental attempt to treat severe blindness, Nature reported. Researchers extracted the energy-producing organelles from the woman's leg muscles and delivered them directly into the vitreous fluid of both eyes.
A brain bleed in February had damaged the woman's retina and optic nerve, leaving her almost completely blind with pupils that did not react to flashed light. In May, researchers obtained emergency approval from the US Food and Drug Administration to attempt the procedure.
David Putrino, a neuroscientist at the Icahn School of Medicine at Mount Sinai and co-author of a preprint posted on August 10, said the team aimed to determine whether the organelles could protect retinal ganglion cells. These inner retinal neurons send vision signals to the brain. Prior rodent studies showed that delivering mitochondria into vitreous fluid supported the survival of viable neurons after optic-nerve trauma.
Clinical evaluations after the injections revealed no inflammation or physical damage in either eye. Putrino explained that the primary safety concern had been an immune reaction against injected materials, but the autologous transfer avoided rejection. Previous human trials had transplanted mitochondria into the heart and brain, making this the first attempt inside human eyes.
The injections triggered measurable pupil responses to light, but the effect subsided after approximately four weeks and failed to restore the woman's sight. Temurkhan Ayupov, a mitochondria biologist at the Institute of Molecular and Clinical Ophthalmology Basel, said the preprint demonstrates that injecting a patient's own mitochondria into eyes is relatively safe, though it does not confirm therapeutic efficacy.
Low-vision assessments conducted after the transplant noted that the patient perceived shapes and shadows in her left eye, Putrino reported. He stated that while the team was not attempting to prove clinical efficacy, light responses remained higher than baseline measurements recorded before the procedure.
