Four extra months
Mice given an experimental compound that blocks an enzyme called AEP lived about 17% longer than untreated animals, according to a study published in iScience. Untreated mice in the experiment averaged 24 months of age at death; treated mice averaged 28. All the animals were around 18 months old when the study began, which is middle to old age for a mouse.
The compound, labelled #11a, was mixed into the food of one group while a control group ate normally. AEP — asparagine endopeptidase — is a protease that cuts other proteins, and earlier work has linked its activity to several diseases of ageing, including neurodegeneration.
Beyond lifespan
The treated animals also looked healthier. They showed fewer signs of frailty, performed better on tests of exercise capacity, grip strength and memory, and had improved metabolic markers, including a better response to insulin. The authors write that AEP is involved in several ageing-related processes, so blocking it may address more than one pathway at once.
Independent researchers have responded with interest and caution in roughly equal measure. Mouse longevity results have a long history of failing to transfer to people, and a single study in one strain is not a replication.
Far from a human pill
No human trial has been run, and the dose, safety and long-term effects of AEP inhibition in people are unknown. The compound used here is a laboratory tool, not a medicine. Still, the study adds to a growing body of work that treats ageing as a set of biological processes that can be measured and, in principle, slowed. Other recent experiments have extended mouse lifespan by blocking inflammation signals or altering nutrient-sensing pathways, and none has yet produced a proven therapy for healthy human ageing.
The next step for this group will be to test whether the effect holds in larger animals and whether the compound is safe enough for early human studies. Until then, the finding is a signal about mechanism rather than a prescription.