Photograph: Dan Saelinger

Rebuilt Lungs

Until this year, the lung had resisted all attempts to replicate its mind-boggling complexity. But in May, researchers in Boston announced that they'd isolated the first-known human lung stem cells. Injected into injured mouse lungs, the cells sprouted mouse-sized human bronchioles, alveoli, and blood vessels.



How Soon: This procedure is still a long way off; the research is in the earliest stages.

Memory-Boosting Nasal Spray

In new research from Harvard and Tel Aviv Universities, a nasal vaccine activated immune cells in the brain that cleared away waxy plaques from blood vessels—plaques believed to contribute to Alzheimer's disease. After receiving the sniffable vaccine, mice with a genetic predisposition to Alzheimer's had fewer plaque deposits and performed much better on mouse memory tests.



How Soon: The researchers hope to begin human trials as soon as 2014.

Fat to Make You Thin

After Johns Hopkins researchers genetically reprogrammed a small part of the DNA in the brains of rats, some of the animals' lumpy white fat transformed into brown fat, the type that actually burns calories. The scientists hypothesize that messages from the altered hypothalamus woke dormant brown-fat stem cells and prompted them to make new tissue. Afterward the mice gained little weight, even when fed fattening chow.



How Soon: The goal is to make these kinds of tweaks to human DNA within a decade.