Medical researchers have found a way to reverse a cause of aging in animals - and it doesn't involve starvation.
The work relates to mitochondria, which are our cells' battery packs and give energy to carry out key biological functions, and a series of molecular eventsthat enable communication inside cells between the mitochondria and the nucleus. As communication breaks down, aging accelerates.
The background to the research is that as we age, levels of the chemical NAD, which facilitate this cellular 'communication', decline. The only way to slow the NAD drop was to restrict calories and exercise intensively. In this work, the researchers used a compound that cells transform into NAD to repair the broken network and rapidly restore communication and mitochondrial function. It mimics the effects of diet and exercise.
While Professor David Sinclair of Harvard Medical School's group was working on muscles in tissue culture, colleagues at University of New South Wales (UNSW) in Sydney were working on animal models to prove the work could have the same results.
"It was shocking how quickly it happened," says co-author Dr Nigel Turner, an ARC Future Fellow from UNSW's Department of Pharmacology. "If the compound is administered early enough in the aging process, in just a week, the muscles of the older mice were indistinguishable from the younger animals."
The mice, which were two-years-old, also performed well on insulin resistance and inflammation – both of which are correlated with aging. They were compared with six-month-old animals.
"It was a very pronounced effect," says Dr Turner. "It's something like a 60-year-old being similar to a 20-year-old on some measures."
The younger mice given the same compound were "supercharged above normal level" on certain measures, according to Dr Turner. "So it is possible this would have benefits in healthy, young humans."
One particularly important aspect of this research involves HIF-1, which is an intrusive molecule that foils communication, but also has a role in cancer. It has been known for some time that HIF-1 is switched on in many cancers, now this research has found it also switches on during ageing.
"We become cancer-like in our aging process," says Professor Sinclair. "Nobody has linked cancer and aging like this before." This may explain why the greatest risk of cancer is age.
The researchers are now looking at the longer-term outcomes the NAD-producing compound has on mice. They are exploring whether it can be used to safely treat rare mitochondrial diseases and other conditions, such as type 1 and type 2 diabetes, as well as for longevity and good health.
"There's clearly much more work to be done here, but if those results stand, then ageing may be a reversible condition, if it is caught early," says Professor Sinclair.
Well, aging can be detected at birth, if that will help.
The researchers hope to start human trials late next year.
Cell. Source: University of New South Wales