A new study published in the journal Nature Communications shows mice that got stem cell injections improved their health and lived two to three times longer than expected, Previous research has revealed stem cell dysfunction, such as poor replication and differentiation, in a variety of tissues in old age, but it wasn’t clear whether that loss of function contributed to the aging process or was a result of it, say senior investigators Johnny Huard, professor of orthopaedic surgery of microbiology and molecular genetics and Laura Niedernhofer, associate professor of microbiology and molecular genetics at the University of Pittsburgh.“Our experiments showed that mice that have progeria, a disorder of premature aging, were healthier and lived longer after an injection of stem cells from young, healthy animals,” Niedernhofer says. “That tells us that stem cell dysfunction is a cause of the changes we see with aging.