Scientists in China have slowed signs of ageing in monkeys using modified stem cells, potentially paving the way for stem cell-based treatments for age-related health conditions. 

With ageing, the body loses its capacity to recover from damage and organs begin to fail, partly because stem cells become less effective at replacing old or damaged cells. However, progress in stem cell therapy for ageing has been limited, due to the risk that transplanted stem cells may grow uncontrollably and form tumours. 

Researchers from the Chinese Academy of Sciences and Xuanwu Hospital Capital Medical University have genetically altered human stem cells to make them resistant to cellular ageing and prevent tumour formation.  

The modified cells were injected twice a week into elderly macaques, which are comparable to humans in their 60s and 70s. After 44 weeks, the macaques had no adverse effects, including no tumours. The monkeys that received the treatment were better at solving tasks that involved memory and thinking, and more than half of the 61 tissues analysed, including brain, bones and reproductive tissues, had fewer morphological  signs of ageing-related decline. 

The study, published in the journal Cell, suggests stem cells could be a safe tool for further studies in clinical trials to counteract the effects of ageing across multiple organs.