The researchers say senolytics "could keep the effects of aging at bay and significantly extend the healthspan of patients."
Published in the journal Aging Cell, the study reveals how the newly discovered drugs - named "senolytics" - successfully target and kill aging-related senescent cells without damaging other cells nearby.
Senescent cells are cells that stop dividing as we age. They accumulate in various body tissues, secreting proteins that cause damage to surrounding healthy cells and tissues. Senescent cells speed up the aging process and play a significant role in the development of age-related diseases.
The research team - led by Prof. Paul Robbins and Dr. Laura Niedernhofer of The Scripps Research Institute (TSRI) - already knew that killing senescent cells in mice could increase their healthy lifespan, and hypothesized that doing so in humans would have a similar effect.
However, the team needed to find a way to target and kill the senescent cells while avoiding harm to surrounding cells.
In their study, the researchers found that - just like cancer cells - senescent cells have increased expression of "pro-survival networks" that allow them to resist programmed cell death, or apoptosis.
As such, the team set out to identify drugs that target senescent cells and induce apoptosis.
A single dose produced significant anti-aging effects
From testing 46 drugs on human senescent cells in culture, the researchers identified two that showed promise: a cancer drug called dasatinib (brand name Sprycel), and an antihistamine and anti-inflammatory supplement called quercetin.
Used together, the researchers found the compounds effectively induced apoptosis in senescent cells.
On testing a combination of the two drugs in mouse models, the team found they significantly improved cardiovascular function, boosted exercised endurance, reduced osteoporosis and frailty and dramatically extended the animals' lifespan. "Remarkably, in some cases, these drugs did so with only a single course of treatment," says Dr. Niedernhofer.
In detail, a single dose of senolytics improved the cardiovascular function of older mice within 5 days, while one dose was found to significantly boost exercise endurance in weak mice that had been exposed to radiation therapy. The team says these effects lasted for at least 7 months.
Among mice with accelerated aging, the researchers found regular administration of the senolytics delayed age-related symptoms, spine degeneration and osteoporosis, and increased their healthy lifespan.
Senior study author Dr. James Kirkland, head of the Mayo Clinic Kogod Center on Aging, explains the findings further in the video below:
Commenting on their findings, Prof. Robbins says the team sees this study as a "big first step" toward developing drugs that extend patients' healthy lifespan and tackle age-related diseases. "When senolytic agents, like the combination we identified, are used clinically, the results could be transformative," he adds.
While both drugs are already approved for separate use in humans, the researchers note that further testing is required to determine if combination use would be safe. They point out that the drugs may have side effects, particularly if used long term.
Still, the team remains very optimistic about the findings. Dr. Kirkland says:
"If translatable to humans - which makes sense as we were using human cells in many of the tests - this type of therapy could keep the effects of aging at bay and significantly extend the healthspan of patients."
In December 2014, Medical News Today reported on a study published in The BMJ, in which researchers claim following the Mediterranean diet could help slow the aging process.