A robust gut lining is important for our overall health Shutterstock/3dMediSphere As we age, the cells that line our intestine gradually lose their ability to renew themselves, which is important for maintaining good immune health. But now, scientists have reversed this process in older mice using genetically engineered immune cells. Known as CAR T-cell therapy, this is most commonly used to treat some kinds of blood cancer. This involves collecting a sample of someone’s immune cells, called T-cells, reprogramming them in the laboratory to target and kill cancer cells, multiplying them, and then infusing them back into the bloodstream. Variations on the technique have also recently shown potential for treating solid tumours, as well as for preventing clogged arteries and treating the autoimmune condition lupus. In this latest study, Semir Beyaz at Cold Spring Harbor Laboratory in New York state and his colleagues wondered about the therapy’s potential for restoring function in an ageing intestine. They wanted to target senescent cells. These cells, which accumulate with age, have lost their ability to divide but remain …