There are many biological processes that naturally slow down or falter as we age, and a growing number of studies are looking at ways to interrupt that decline – to keep us living healthier for longer.One of the ways old age affects the body is via changes to hepatocyte growth factor (HGF), a protein that helps activate muscle repair.A few years ago, researchers from Kyushu University in Japan discovered that HGF undergoes a damaging chemical process called nitration as the years tick by, breaking the key muscle repair signal. Could there be some way to protect HGF from this age-related alteration? That was the question the team sought to answer next. In a new study, published in Scientific Reports, they tested two compounds designed to counter the effects of nitration via antioxidants – protective molecules that intercept the sabotaging chemical chain reaction."HGF is not necessarily missing as we age," says biologist Ryuichi Tatsumi, from Kyushu University."Rather, it can be chemically altered after it is made. That led us to wonder whether a compound with strong antioxidant capacity might protect HGF, either by preventing nitration or by compensating for the functional loss it causes."