Protein Hints at a Fountain of Youth in Blood

A protein has been added to blood cells that appears to make them young again—cue the speculation on whether this substance is, at long last, a way to reliably reverse some of the effects of aging.

According to New Scientist, researchers discovered that older mice had low levels of a protein called osteopontin, and that stem cells injected into the mice quickly aged. The reverse—putting old stem cells into a dish filled with osteopontin—appeared to rejuvenate them. The team behind the work say they are developing a drug that they hope could be used to, as one of the researchers put it, "make old blood young again," and boost older people’s immune systems.

The thing is, the gap between a bit of primary research and a clinically effective drug is huge—especially in the anti-aging arena. Several years ago, scientists and the public alike were excited to learn that when an old mouse and a young mouse were surgically joined so that they shared a circulatory system, the old mouse showed many signs of growing young again. The secret to prolonging life, it seemed, was in youthful blood.

Subsequent experiments have produced, you’ll forgive the expression, mixed results. In one, old blood turned out to be terrible for young mice, while young blood didn’t do much for the elderly. That hasn’t stopped the idea from getting the Silicon Valley treatment: Folks who pony up $8,000 to a startup called Ambrosia will receive a two-liter bagful of young-person blood plasma. The company’s founder is billing it as a clinical trial, but some say it looks a lot more like a scam.

What it comes down to is that no one knows what it is about young blood that causes the rejuvenation effect—or whether blood is even the most important part of the equation. Last year, a team of researchers at the Salk Institute genetically engineered mice so that they bore extra copies of genes known be able to turn back the biological clock on adult cells, transforming them into something resembling embryonic cells. By controlling the expression of these genes, the researchers were able to get the mice to live 30 percent longer than they normally would.

That doesn’t mean the discoverers of osteopontin are wrong to pursue their work. Clearly something very interesting is going on that suggests aging is not the immutable force we take it to be. The question that these and many other researchers are trying to answer, is just what that something is.