Getting rid of senescent cells improves health in mice. In the picture we can see two mice of the same age, however one of them has lordokyphosis (the obvious problem with the spine), sarcopenia (loss of muscle mass), cataracts and other age-related pathologies. The other one has got its senescent cells removed by the group of researchers led by Darren J. Baker and Jan M. van Deursen at the Mayo Clinic in Rochester, Minnesota. Senescent cells are the aged cells that stopped dividing, but still secreting tons of various molecules into their environment. A lot of those molecules are harmful. The hypothesis expressed by Dr. Judith Campisi was that these senescent cells contribute to aging processes in our tissues and are the cause of aging and pathologies. In the paper published in Nature Journal the link between the presence of senescent cells and age-related diseases was established. Researchers took a rapidly aging strain of mice and genetically changed them in a way to be able to selectively kill these senescent cells that expressed the p16Ink4a gene by triggering apoptosis (cell suicide). Senescent cells were removed only from the skeletal muscles, fat tissue and lens. As a result there was a significant reduction in aging pathologies in these tissues. Unfortunately, there was no difference in life span, but researchers believe it was because the main reason of death in this strain is heart failure. Senescent cells were not removed from the arteries walls and cardiac muscles, so this may be the reason why both groups of mice live the same amount of time. It would be very interesting to see if lifespan will be increased if researchers remove senescent cells from all of the tissues.