Can aging be reversed? For now, scientists are asking a smaller but more realistic question: can aged cells be pushed back toward a younger state without changing what kind of cells they are? In April 2026, Nature reported that this idea is reaching its first human clinical test. The therapy, called ER-100, has received US FDA clearance, and a Phase 1 trial is recruiting people with open-angle glaucoma and non-arteritic anterior ischemic optic neuropathy, two eye diseases that damage retinal ganglion cells and can lead to permanent vision loss. The study plans to enroll up to 18 participants and follow them for as long as five years. (nature.com)
The science behind ER-100 comes from “partial epigenetic reprogramming.” In 2006, Shinya Yamanaka showed that a small set of genes could turn adult cells into stem cells. But full reprogramming is risky, because cells can lose their identity and even form tumors. ER-100 uses only three of the four classic Yamanaka factors — OCT4, SOX2 and KLF4, often called OSK — in an effort to reset some age-related epigenetic marks while keeping retinal cells as retinal cells. In this trial, the genes are delivered by a modified adeno-associated virus into one eye, and their activity is switched on with doxycycline for eight weeks. (trialstoday.org)
Why start with the eye? Researchers see it as a practical and relatively controlled target. The tissue is accessible, doctors can measure vision and retinal structure very precisely, and a local treatment may reduce whole-body risks. The excitement also comes from earlier animal studies: a 2020 Nature paper reported that OSK restored youthful DNA methylation patterns, promoted optic nerve regeneration, and reversed vision loss in aged mice and in a mouse model of glaucoma. Life Biosciences has also said that preclinical work in nonhuman primates showed controlled OSK expression, restoration of methylation patterns, and improved visual function. (nature.com)
Still, this is not a proof that humans can “become young again.” Phase 1 trials are mainly about safety, and major questions remain about long-term effects, efficiency, and whether changes in epigenetic age truly mean real rejuvenation. Even so, the field has crossed an important line: the idea of reversing at least some features of cellular aging is no longer only a mouse experiment. It is now a careful human test. (trialstoday.org)










