As we get older, NAD+ levels decrease, allowing DNA damage to build up. These mutations aren’t a direct cause of the progressive deterioration associated with aging, Sinclair said. “Cells cope with the damage by turning on the wrong genes at the wrong time,” he explained.
If NAD+ levels could be increased, Sinclair and his team hypothesized, perhaps the damage could be reversed.
They tested their theory on a group of older mice with low NAD+ levels. For a week, the mice drank a special serum of water mixed with NMN, a precursor of NAD+ that’s small enough to pass through the cellular wall. Once inside the mice’s cells, the NMN bonded with NMN molecules to form more NAD+.
“After just a week, we couldn’t tell the difference between the young mice and the old mice when we looked at their tissues,” said Sinclair.
Now Sinclair's team is moving toward human trials of the NAD+ booster, with the hope of getting a drug on the market within the next five years.
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“Our technology in the animals slows down the appearance of diseases, and that’s how we know that it’s slowing down aging itself. And as a consequence of being healthier, the animals live longer,” said Sinclair. “We think the same will happen in people. If we can delay all major diseases, then we will extend people’s lives, but only because they’re healthier. We’re not going to see people spend longer in nursing homes. We’re going to see them spend more time out of nursing homes.”
But even if Sinclair’s drug proves to delay the onset of age-related diseases in humans — effectively prolonging the human lifespan — it won’t be marketed as an “anti-aging” pill. That is, not unless the US Food and Drug Administration (FDA) accepts that aging is a treatable condition.
The FDA approves drugs for specific “indications” or recognized medical conditions. For example, the indication for a statin drug like Lipitor is cardiovascular disease, and one of the indications for Xanax is anxiety disorder. While the FDA approves drugs indicated for age-related diseases like cancer, type-2 diabetes, and dementia, it doesn’t recognize aging as its own indication... yet.
In June 2015, a group of scientists working under the American Federation for Aging Research (AFAR) met with FDA officials to make an ambitious proposal. Instead of approving a drug for one or two indications, they wanted the FDA to give their blessing to a clinical trial that would test a single drug’s effectiveness at preventing all of the major age-related illnesses at once: cancer, cardiovascular disease, dementia, and type-2 diabetes.
“We worked for weeks honing our arguments and our strategies for trying to convince them,” said Steven Austad, science director at AFAR and chair of the biology department at the University of Alabama Birmingham. “When we actually got into the meeting, within the first 15 minutes they said, ‘OK, that sounds good. Now let’s talk about the design of your study.’ We were kind of taken aback that they had accepted our logic so easily.”