Researchers say clearing these aging cells from the body can slow down or reverse diseases such as Parkinson’s and Alzheimer’s.
A new study shows that removing “zombie” cells — also known as senescent (aging or deteriorating) cells — from the body has the potential to slow down or even reverse some major diseases associated with aging.
Scientists have long known that an accumulation of senescent cells is linked to conditions such as arthritis, Parkinson’s disease, and Alzheimer’s disease.
Despite the potential shown in this recent research, Dr. James Kirkland, a professor of physiology and medicine at the Mayo Clinic in Rochester, Minnesota and senior study author, emphasized that the process isn’t a magic bullet.
“It’s a very preliminary study and we should plan other trials,” Dr. Kirkland told Healthline. “The biggest risk factor for most people is still their chronological age.”
Think of “zombie” cells as little vacuum cleaners that no longer work efficiently. But because they still work a bit, they’re not cleared out by the body.
At the same time, they’re too damaged to carry out their normal functions or repair tissue. So they clog up the works, leading to a gradual deterioration of the body.
In previous studies done with animals, removing these cells reversed the aging process and extended life span.
The most recent study showed improvements in humans for the first time. The three-week trial with 14 volunteers — all elderly and with pulmonary fibrosis — was intended to investigate the safety of a new drug.
The fact that the test subjects were able to walk more quickly, get up from a chair more easily, and scored better in ability tests was an unintended benefit.
Specifically, the results showed that after the trial, participants could walk an extra 25 yards during a 6-minute jaunt, and get up from their chairs 2 seconds more quickly.
They also scored an extra point on functionality tests, moving from an average of 10 points to 11 points.
“This is a glimmer that the drug might actually work. The results were impressive. All 14 people got better in their functional ability,” Kirkland told The Telegraph in England.
The new treatment, named DQ, uses a drug called dasatnib, which is already licensed for killing cancer cells in people with leukemia, and the drug quercetin, a common plant pigment found in red wine, onions, green tea, apples, berries, Ginkgo biloba, and St John’s wort.
The drug combination began clearing out the “zombie” cells within 30 minutes, and within 24 hours, all senescent cells were gone, the researchers reported.
Pulmonary fibrosis is a scarring of the lungs that prevents oxygen moving around the body. It leads to shortness of breath, aching muscles and joints, and severe fatigue.
People diagnosed with pulmonary fibrosis usually survive only six to eight years after diagnosis. Researchers see the treatment potential here.
“The new drug has a hit-and-run effect,” Kirkland said. “It starts working quickly, so it would be ideal to be able to give it just once a month.”
The process is much like developing antibiotics, he said. Other scientists also see the potential.
“We’ve known for some time that senescent cells accumulate with age and contribute directly to the aging process,” Lorna Harries, PhD, associate professor in molecular genetics at the University of Exeter in England, told Healthline. “However, until now we’ve only been able to assess the effects of drugs that target these cells in culture or animal models.”
“We now suspect that many of the diseases of aging share common mechanisms,” she said, “so drugs that target senescent cells or modify their characteristics may represent a new avenue of treatment for other diseases of aging in the future.”
“We still have a ways to go before this eventual aim can be realized, but this work represents an important first step,” Dr. Harries said.
At this point, scientists are focusing on serious conditions where the risk-benefit analysis is in the person’s favor, Kirkland said.
“There will be issues we’ll come across,” he said. “What are the side effects? What’s the right dosage? How frequently do we administer it? Will this lead to treatment for other conditions and eventually to prevention?”
Dr. Francis Collins, director of the National Institutes of Health, expressed optimism but also caution in a recent blog.
“Caution is warranted as we learn more about the associated risks and benefits, but it’s safe to say we’ll be hearing a lot more about senolytics in the years ahead,” Dr. Collins wrote.