Some researchers speculate that these observations suggest we can extend healthspan through extending lifespans. Others speculate that ageing can actually be reversed. A gene therapy has been mooted to treat multiple age-related diseases, restoring youthful function in some systems, for example.30 Animal experiments have identified age-associated biomarkers which can be delayed, stopped and even in some cases reversed.31 Stem cells can be reset to age 0 - these have been used to regenerate a crushed optic nerve in rats.32 Gene therapy has reprogrammed epigenetic information to reverse glaucoma in a mouse model.33 Organ replacement, and next-generation drugs also may reset the body’s clock to an earlier state.
According to a more ambitious theory of ageing, a loss of epigenetic information is a reversible cause of ageing and accelerates its hallmarks.34 Proponents claim that such changes can be reversed by epigenetic reprogramming, driving the entire system of ageing backwards. These techniques include partial reprogramming (which erases a cell’s identity and reverts it back to a stem-cell-like state),35 and gene therapy,3637 the delivery of genetic instructions for making proteins that can travel in the blood to multiple tissues.
