Senescent Cells: The little-known cause of aging
Anti-aging is huge business. Countless creams, lotions and potions flood the market, promising to minimize the signs of age. Plastic surgeons and med-spas are never at a loss for business. These will never go away. All people—men and women—want to look and feel young and vibrant, no matter what their “real” age.
But while these treatments address the surface signs of aging, research reveals that the real secret to turning back the hands of time is addressing a phenomenon that occurs at the cellular level: senescence.
What Is Senescence?
During our younger years, our bodies are efficiently able to eliminate cells that become senescent—damaged, dysfunctional, and no longer able to divide and multiply as they normally do. The body destroys senescent cells in a process known as apoptosis (programmed cell death), and then they’re disposed of by the immune system.
As we age, though, more and more of our cells become senescent at a faster pace. This typically happens as a result of DNA/telomere damage or oxidative stress.
The problem is, our immune system also tends to decline with age and becomes less effective. When this happens, more and more senescent cells escape apoptosis and elimination, which causes them to accumulate in the body.
Research is starting to realize that senescent cell accumulation is one of the main causes of aging and a major reason we start to develop so-called age-related diseases such as osteoarthritis, cancer, vision loss, neurodegenerative disorders, atherosclerosis, and heart disease.
This is because senescent cells, sometimes referred to as “zombie cells”, not only stop functioning normally, contributing to the greater good of your body as a whole, they instead release protein-degrading enzymes and pro-inflammatory signals.
As you know, chronic inflammation is a major risk factor for a multitude of diseases.
To make matters worse, the inflammatory signals sent out by “zombie” cells can negatively impact surrounding healthy cells, causing them to prematurely enter into a senescent state. It’s a cycle that perpetuates and accelerates aging, illness, and disease.
Fortunately, studies show that a novel approach called senotherapeutics can help to clear out these problematic cells and therefore lower risk of disease.1
Senotherapeutics are medicines or compounds that selectively target senescent cells. They work by either suppressing their inflammatory effects (senomorphics) or killing senescent cells (senolytics). Specifically, senolytics work by “turning off” the pathway that prevents apoptosis and “turning on” the signals that lead to cellular death. As a result, senescent cells can be safely eliminated from the body without harming any healthy cells.
Preliminary studies using mice show that the use of senotherapeutics decreases disease risk. Studies show that removing senescent cells can delay or slow the progression of certain diseases. In one, the removal of senescent cells led to inhibition of arterial plaque in mice with atherosclerosis. 2-3
Quercetin and Fisetin as Senolytics
Preliminary research appears to show that the bioflavonoid quercetin, when combined with other senolytics, is able to release senescent cells from the body. Quercetin is a plant pigment found in the skins of grapes, onions, and apples. Supplemental quercetin has long been used as an antioxidant and anti-inflammatory, and it’s also a powerful natural allergy fighter.
In a study released in 2018, researchers at the Mayo Clinic found that quercetin, combined with the chemotherapy agent dasatinib, cleared senescent cells from mice.5
They injected young, four-month-old mice with either senescent cells or non-senescent cells (the control group). Just two weeks later, the mice with senescent cells started showing signs of aging—impaired function, including decreased strength, endurance, speed, activity level, food intake, and body weight.
Both sets of mice were treated for three days the with quercetin/dasatinib combination. They found that the therapy “selectively killed senescent cells and slowed the deterioration in walking speed, endurance, and grip strength” in the senescent mice.
Older, 20-month-old mice were also tested with the treatment combo. Those mice experienced improved physical function, faster walking speed, and better grip strength.
When very old mice (24-27 months old) were given the quercetin/dasatinib therapy biweekly, it led to a 36 percent higher average life span, indicating that senolytics can lower risk of death.
Other research has shown that a flavonoid in strawberries, fisetin, also acts as a senolytic agent. Old mice treated with it displayed “restored tissue homeostasis, reduced age-related pathology, and extended median and maximum lifespan.”5
What You Can Do
Research into senolytics is still so young, and there’s years—perhaps decades—of work to be done before any definitive answers can be provided. But the early results are so promising that it’s worth taking advantage of the senolytic agents we do have at our disposal.
Obviously, chemotherapy agents are not available over the counter, so the average Joe cannot start using a quercetin/dasatinib therapy on his own. Not to mention, chemo drugs come with their own list of side effects.
However, both fisetin and quercetin supplements are readily available online and at almost all health food stores and pharmacies. There’s no definitive proof that these supplements will reverse the aging process, but for their antioxidant and anti-inflammatory effects alone, they are worth adding into your supplement regimen. Use as directed.
- Kim EC and Kim JR. Senotherapeutics: emerging strategy for healthy aging and age-related disease. BMB Rep. 2019 Jan;52(1): 47-55. Last accessed Sept. 12, 2019.
- Childs BG, et al. Senescent intimal foam cells are deleterious at all stages of atherosclerosis. Science. 2016;354(6311):472-7. Last accessed Sept. 13, 2019.
- Baker DJ, et al. Clearance of p16Ink4a-positive senescent cells delays ageing-associated disorders. Nature. 2011 Nov 2;479(7372):232-6. Last accessed Sept. 13, 2019.
- National Institute on Aging press release. Senolytic drugs revise damage caused by senescent cells in mice. July 9, 2018. Last accessed Sept. 13, 2019.
- Yousefzadeh MJ, et al. Fisten is a senotherapeutic that extends health and lifespan. Ebiomedicine. 2018 Oct;36:18-28. Last accessed Sept. 13, 2019.