In a New York laboratory, a special group of mice is destined to outlive their cage-mates. Their muscles will stay strong for longer. Their brains will stay sharp for longer. When they eventually die, they will have seen more months than their peers.The secret to their longevity isn’t a drug or a special diet. Instead, Dongsheng Cai from the Albert Einstein College of Medicine simply reduced the levels of a single protein called NF-kB in part of the brain called the hypothalamus. That was enough to extend their lives.