A research group led by the Buck Institute for Research on Aging (California, USA), in collaboration with the Georgia Institute of Technology (Georgia, USA), reports that they reversed the aging process for human adult stem cells. The findings could lead to medical treatments that may repair a host of ailments that occur because of tissue damage as people age.  The collaborators used adult stem cells from humans and combined experimental techniques with computational approaches to study the changes in the genome associated with aging. They compared freshly isolated human adult stem cells from young individuals, which can self-renew, to cells from the same individuals that were subjected to prolonged passaging in culture. This accelerated model of adult stem cell aging exhausts the regenerative capacity of the adult stem cells. Researchers looked at the changes in genomic sites that accumulate DNA damage in both groups. They found the majority of DNA damage and associated chromatin changes that occurred with adult stem cell aging were due to parts of the genome known as retrotransposons, which were previously thought to be non-functional and were even labeled as 'junk DNA', but accumulating evidence indicates these elements play an important role in genome regulation. While the young adult stem cells were able to suppress transcriptional activity of these genomic elements and deal with the damage to the DNA, older adult stem cells were not able to scavenge this transcription. Victoria Lunyak, from the Buck Institute, comments that:  "We demonstrated that we were able to reverse the process of aging for human adult stem cells by intervening with the activity of non-protein coding RNAs originated from genomic regions once dismissed as non-functional 'genomic junk'.”