“We discovered that CBP predicts lifespan and accounts for 80 percent of lifespan variation in mammals,” said Dr. Mobbs. “Finding the right balance is key; only a 10 percent restriction will produce a small increase in lifespan, whereas an 80 percent restriction will lead to a shorter life due to starvation.”
The team found an optimal dietary restriction, estimated to be equivalent to a 30 percent caloric reduction in mammals, increased lifespan over 50 percent while slowing the development of an age-related pathology similar to Alzheimer’s disease….
researchers found that when dietary restriction was maintained throughout the worms' adulthood, lifespan increased by 65 percent and the Alzheimer's disease-related paralysis decreased by about 50 percent.
“We showed that dietary restriction activates CBP in a roundworm model, and when we blocked this activation, we blocked all the protective effects of dietary restriction,” said Dr. Mobbs. “It was the result of blocking CBP activation, which inhibited all the protective effects of dietary restriction, that confirmed to us that CBP plays a key role in mediating the protective effects of dietary restriction on lifespan and age-related disease. ”
In the second part of study, Dr. Mobbs and his team looked at the other end of this process: What happens to CBP in a high-calorie diet that has led to diabetes, a disease in which glucose metabolism is impaired? Researchers examined mice and found that diabetes reduces activation of CBP, leading Dr. Mobbs to conclude that a high-calorie diet that leads to diabetes would have the opposite effect of dietary restriction and would accelerate aging.
Dr. Mobbs hypothesizes that dietary restriction induces CBP by blocking glucose metabolism, which produces oxidative stress, a cellular process that leads to tissue damage and also promotes cancer cell growth. Interestingly, dietary restriction triggers CBP for as long as the restriction is maintained, suggesting that the protective effects may wear off if higher dietary intake resumes. CBP responds to changes in glucose within hours, indicating genetic communications respond quickly to fluctuations in dietary intake.
“Our next step is to understand the exact interactions of CBP with other transcription factors that mediate its protective effects with age,” said Dr. Mobbs. “If we can map out these interactions, we could then begin to produce more targeted drugs that mimic the protective effects of CBP.”