Cellular senescence, or the process by which normal cells stop dividing in response to stress or damage to their DNA, can be both beneficial and harmful. It can be beneficial in assisting wound-healing and preventing the excessive growth seen in cancers. On the other hand, it can drive ageing and age-related diseases by changing the tissue environment. This happens when the senescent cells trigger a cascade of chemical signals that cause inflammation and damage to local cells and tissue.

A gene therapy intended as a one-time treatment for dry age-related macular degeneration (AMD) has been successfully administered to a patient in the UK, marking the start of one of the first clinical trials of its kind. The therapy consists of a recombinant non-replicating adeno-associated viral (AAV) vector encoding a human complement factor.