Senolytics is an emerging concept of aging that just might lead scientists to the proverbial Fountain of Youth.
Aging brings with it an inevitable decrease in physical and mental abilities. Our muscles grow weaker, our bones more brittle, and our bodies become more susceptible to injury and disease. But what if there were a way to change all of that? The emerging science of “senolytics” may hold the key.
What is Senolytics?
Every cell in your body has a lifecycle and a lifespan, all of its own. New, young cells are strong, and they renew themselves through cellular division. But, every cell eventually reaches a point when it can no longer divide. And it goes into a kind of hibernation called senescence. Senescent cells are “programmed” to eventually destroy themselves in a process known as apoptosis. When we are young, this process runs very smoothly, with senescent cells dying off as they are supposed to and being replaced with young, vital cells. However, as we reach a certain age, something happens, and senescent cells remain as such, in a zombie-like state, instead of dying off. They build up in the bloodstream and organs, causing inflammation, damage to other cells, and many scientists believe most if not all of the “symptoms” we attribute to aging.
“Senolytics” is an encompassing term that is used to describe any “senolytic” compound or therapeutic that works to eliminate “senescent” cells from the body.
The problem is that senescent cells are very hard to kill. So, senolytic drugs need to be very powerful and very targeted so that they kill off senescent cells while leaving surrounding healthy cells undamaged.
“It’s very hard to kill [senescent cells],” says James Kirkland, a Mayo Clinic researcher who specializes in cellular senescence. “If you grow them under conditions that would kill a normal cell … they’ll survive and sometimes survive for years under those conditions.”
Senolytics were first studied for their antiaging potential in 2011 by a team lead by Kirkland. Since then, senolytics have garnered attention from scientists around the globe. A 2016 trial showed an increase in the lifespan of laboratory mice that were given senolytics by 17 to 35 percent.
Current Research Into the Antiaging Benefits of Senolytics
Kirkland and his team continue to research and develop senolytic compounds that they think may someday lead to antiaging drugs. He is joined by many researchers worldwide. At Erasmus University Medical Center in the Netherlands, researchers have identified a peptide that kills senescent cells without damaging surrounding healthy cells. When this peptide was administered to laboratory mice, the results were significant. Patches of missing fur began to regrow on their coats, and they were able to run twice as far as mice from the control group who had not been given the peptide.
While there is still a lot of research that needs to be done before senolytics can be manufactured in pill form or administered to human patients on a large scale, several researchers have begun preliminary human trials. The trials are showing some intriguing and promising results.
One such human trial conducted by University of Texas-San Antonio researchers in collaboration with the Mayo Clinic and Wake Forest School of Medicine showed promising results in the use of senolytics to treat Idiopathic Pulmonary Fibrosis, or IPF a type of lung disease that results in scarring of lung tissue. Patients enrolled in this trial showed an improvement in their six-minute timed walking distance by an average of 21.5 meters, something no other drug or therapy currently available has been shown to improve.
The ultimate promise of senolytics drugs is that of a panacea, a cure-all for the ills of aging.
But such compounds are likely years away from FDA approval. The studies that have so far been completed are preliminary. Larger trials are necessary to replicate their results and to prove that the compounds used in the trials are actually responsible for killing senescent cells.
But the allure of curing, or even just easing, the ills associated with aging is strong. What makes senolytics so promising is they might move us beyond treating symptoms of aging – memory problems, joint aches and pains, greater susceptibility to diseases — and begin addressing its fundamental causes.
“I’m a clinical geriatrician,” Kirkland says. “I’m sick of prescribing better wheelchairs, walkers, and incontinence devices. I’d like to do something fundamental that could slow down these processes and maybe even partially reverse them in older people.”
