What are "zombie cells" and how do you get rid of them?
Zombie cells clearly play a role in ageing, but no proven treatment yet exists for humans. Keep an eye on the field, but for now do not stock up on supplements or products claiming to be senolytics.
Zombie cells are cells that have stopped dividing but refuse to die. They accumulate as you age and continuously pump inflammatory substances into their surroundings. Those substances damage neighbouring healthy cells and tissues and have been linked to multiple age-related diseases, from joint problems to brain disorders.
Not all zombie cells are harmful. During embryonic development and in ordinary wound healing they actually play a useful role: they inhibit uncontrolled cell growth and help renew tissue. The problem only arises when they build up for too long and the immune system can no longer clear them in time. In people with chronic diabetic foot wounds you can see exactly that going wrong: senescent cells accumulate and inhibit the healing process that they would accelerate in a normal wound.
In mouse models of Alzheimer-like brain diseases, zombie cells were also found in brain support cells. Early intervention by removing those cells prevented tau accumulation, brain inflammation and neuron loss, and kept memory better intact. This has been demonstrated exclusively in animal research; whether it works in humans is still unknown.
Several strategies have now been investigated for the targeted removal of zombie cells, so-called senolytics. The drug navitoclax activates programmed cell death specifically in senescent cells; in mice it rejuvenated blood-forming tissue and muscle tissue. Researchers at Erasmus MC designed a peptide that prompts senescent cells to self-destruct without affecting healthy cells: mice looked healthier and their kidney function improved. Surprisingly, the common diabetes drug canagliflozin (an SGLT2 inhibitor) also turned out to reduce senescent cells in mice via the immune system, and even to extend lifespan in mice with premature ageing. Notably, ordinary insulin treatment did not have this effect, suggesting it involves more than just lowering blood sugar.
All of these findings come from animal and laboratory research. No proven senolytic treatment is yet available for humans. Researchers are working on measurement methods to identify zombie cells in human tissue, but these are not yet clinically available. The field is active and the results in animals are consistently positive, but the step towards a safe and effective treatment in humans has yet to be taken.
Claims based on PMID 24954210, 28575665, 39310100, 30232451, 26657143, 28340339, 38816549 and 35974106. All intervention results come from animal or laboratory research; no human clinical trials are available for senolytics.
What do zombie cells do to your ageing?
Zombie cells accumulate as you age and accelerate ageing through inflammatory signals; how to tackle them is promising but still very much under investigation.
What are senescent cells and why are they bad for you?
Senescent cells are damaged cells that stop dividing but continue to live and chronically inflame their surroundings. They accumulate as you age and are strongly linked to age-related diseases, but because they also play a protective role, simply clearing them all away is not an option.
Does fisetin from strawberries really work as a zombie-cell clearer?
Fisetin demonstrably clears zombie cells in cell experiments and in animals, but whether this also works in people and is safe has not yet been established. Do not take it as a supplement for now outside ongoing studies in people.
What are free radicals and what do they do to your cells?
Free radicals arise naturally when your cells produce energy and, in small amounts, do useful work. Only when they overwhelm your body's own defence systems do they damage DNA, proteins, and fats, contributing to ageing and disease.
How does air pollution damage your cells from the inside?
Air pollution damages your cells from the inside through oxidative stress: fine particulate matter causes an excess of harmful oxygen molecules that attack your DNA, energy factories, and immune system. Protection begins with limiting exposure, because the damage occurs at the cellular level.
How do telomeres protect your DNA?
Telomeres protect your chromosome ends through a system of proteins that simultaneously prevents false alarms and harmful fusions. If that system fails due to inherited defects, you can develop serious ageing-related diseases.