I COME from a family with iffy knees. My 79 year old dad has had two full knee replacements and my sister needs one at the age of just 54. My left knee aches when I walk downstairs and clicks when I bend it: classic signs of the age-related disease osteoarthritis, caused by wear and tear on the cartilage that cushions the joint.
However, by the time you get to the knee replacement stage, you may not need to go under the knife. Instead, I look forward to swallowing a few pills now and then and feeling my knee pain go away.
Osteoarthritis is not just due to wear and tear, but also to the buildup of some nasty cells that attack the knee joint from the inside. They are called senescent cells: old or deteriorated cells that have reached the end of their lives or have suffered irreversible damage. They should die, and yet they don’t, lurking in the tissue and causing trouble.
Senescent cells are normally eliminated by the immune system, though that goes awry during aging and they accumulate, dripping poison into their surroundings and turning other cells rogue. They are a leading cause of numerous age-related conditionsnot only in the knees but also in the heart, liver, muscles and brain.
It’s no surprise, then, that researchers have been eyeing senescent cells for many years as a juicy target for efforts to slow, stop, or even reverse aging. Now, we have numerous drugs in the pipeline and some tantalizing results from human trials. There is even the hope that by eliminating senescent cells, other causes of aging will also evaporate.
Cellular senescence was…