SLOWING TIME It’s unlikely we can live forever, but researchers are exploring ways to extend health further into old age.
Stem cells from pig fat helped grow bone grafts in a special chamber, shown here.
Sarindr Bhumiratana/Columbia Engineering
GUT REACTION Research on rats and mice suggests that gut bacteria start the cycle of obesity. The bacteria make a molecule called acetate that sends signals through the vagus nerve to stimulate hunger and fat storage.