Promising way to reverse aging
Findings of a new study published in Science could lead to effective anti-ageing drugs.
The study, led by researchers from Harvard Medical School, University of Rochester, Mayo Clinic, University of Bayreuth, and The University of New South Wales, shows that nicotinamide mononucleotide (NMN) -- a naturally occurring compound found in certain vegetables -- has a dramatic rejuvenating effect on aging mice. As the compound may also have the potential to reverse aging in humans, the team plans to conduct clinical trials within six months.
Study leader Dr David Sinclair and the team looked at a molecule called NAD+, the oxidised form of the chemical nicotinamide adenine dinucleotide. NAD+ is present in every cell in the body. In previous work, the team discovered that the levels of NAD+ decline as people age regardless of their health. Moreover, increasing NAD+ levels in older mice made them look like younger mice. This work and many other studies highlighted the anti-ageing properties of NAD+, suggesting that NAD+ supplementation could be a treatment for aging.
For the current study, the team continued exploring the working mechanism of NAD+ and found that NAD+ plays an important role in regulating protein interactions that control DNA repair. When the researchers treated younger mice and older mice with NMN, which is a booster of NAD+, the animals' cells became more capable of repairing DNA damage caused by radiation exposure or old age. “The cells of the old mice were indistinguishable from the young mice, after just one week of treatment," Dr Sinclair stated.
Accumulated DNA damage is a major cause of aging and cancer. DNA damage can occur when a cell divides. Both normal metabolic activities and environmental factors such as radiation, plant toxins, and viruses can cause damage to DNA. In most cases, DNA damage can be repaired because cells have a variety of repair strategies. One is an enzyme called PARP1, short for poly(adenosine diphosphate–ribose) polymerase 1
The researchers found that NAD+ seemed to boost the activity of PARP1. Thus, low NAD+ levels seen in old people could decrease PARP1's ability to repair damaged DNA. In their paper, the researchers detailed how NAD+ works to impact PARP1 activity and keep cells young.