Senescence or the loss of a cells’ ability to divide, normally functions as a tumor suppressing mechanism; however, senescent cells become “toxic” as they accumulate with age. This is because they cause stem cell aging that reduces the ability of tissue regeneration and repair which then drives chronic inflammation and oxidative stress causing further damage and dysfunction. Since chronic inflammation and oxidative stress are thought to be the root cause of many age-related diseases,such as age-related osteoarthritis and atherosclerosis for example.

At the Institute for Regenerative Medicine in Pittsburgh, fast-aging elderly mice with a usual lifespan of approximately 21 days were injected with stem cells from younger mice. They were given an injection of stem cells approximately four days before they were expected to die, and the results were outstanding.