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Aging is an inevitable facet of life. With the rising life expectancy globally, the primary demographic is shifting towards older age groups. The result—a greater burden on our healthcare systems to ensure that those who live longer also lead a healthier life. However, despite medical science's efforts to promote longer lifespans, age-related diseases are on the rise—courtesy of senescent cells, also known as "zombie cells."
Although "zombie cell" might sound like a buzzword born on social media, it is not really a pop culture reference. It's a scientific term introduced in the 2000s to describe harmful aging cells that just won't die! Scientists now believe that killing these senescent cells is the most efficient way to slow down aging. But what exactly are zombie cells, and can we really get rid of them? Let's find out!
What Are Zombie Cells?
Zombie cells, or senescent cells, were first discovered in the 60s by American biologists from the Wistar Institute of Anatomy and Biology in 1961. They found that some human cells stopped dividing after about 50 cell cycles. However, instead of dying like normal cells, these cells entered a quiescent twilight stage of absolute dormancy (due to high anti-apoptotic gene load)—a phenomenon known as senescence.
Why Are Zombie Cells Harmful?
Now, one might argue, what's wrong with a dormant cell that is just lying around minding its own business? Well, a zombie cell doesn't just sit idle. It's like that one bad apple spoiling the bunch. It secretes pro-inflammatory cytokines, sending signals to neighboring healthy cells and accelerating their aging.
When we are young, our sturdy immune system can clear out these cells very well. However, as we age, the clearance rate cannot keep up with the increasing burden of senescent cells.
According to a report from the journal Nature, scientists have found that zombie cells also slow down our body's healing and regenerative properties by causing stem cells to dysfunction. The result—premature wrinkles, cardiovascular ailments, diabetes, Alzheimer's disease, dementia, cataracts, osteoporosis, and even cancer.
Triggers for Zombie Cells
The following factors have been found to speed up cellular senescence in lab studies: Environmental stressors: Free radicals generated from smoking, sun exposure, and environmental pollution directly damage telomeres and cause DNA damage, leading healthy cells into premature senescence.
Oncogene: Oncogenes are genes promoting uncontrolled cell proliferation causing cancers. Multiple clinical trials have confirmed that carcinogens like tobacco, UV radiation, processed meat, asbestos, air pollution, pesticides, and industrial chemicals can activate these oncogenes.
Do Zombie Cells Cause Wrinkles?
With the skin being our body's largest and most exposed organ, its DNA suffers the most due to aging:
Epidermis: Zombie cells weaken the skin barrier, causing skin translucency, fine lines, and crinkles. Barrier disruption, water loss, and susceptibility to allergens cause dryness, eczema, and allergic reactions.
Dermis: Reduce cellular division with thinner skin, delayed wound healing, and decreased strength and elasticity. The result is sagging, wrinkles, and yellowing, with loss of skin glow and turgidity.
How Do I Get Rid of Zombie Cells?
Senescent cells are recognized as one of the nine hallmarks of aging. However, modern medicine has found some 'senotherapeutics' that can prevent the buildup of and clear cells by inducing their apoptosis. There are two groups of therapies in this category: senolytics and senomorphics.
Senolytics: Agents like dasatinib and quercetin are found to selectively target and destroy senescent cells by disrupting their survival pathways in animal and human trials. There is also evidence of their efficacy in promoting regeneration of healthy tissues in patients with age-related changes, cardiovascular diseases, and kidney diseases. Other noteworthy senolytics include navitoclax, FOXO4-DRI, and fisetin.
Senomorphics: They reduce the secretions of harmful substances from senescent cells. Examples include mTOR inhibitors like rapamycin and metformin and natural compounds like resveratrol and omega-3 fatty acids.
How To Remove Senescent Cells Naturally?
To reduce oxidative stress on your cells, you consume foods rich in antioxidants, such as berries, nuts, and leafy greens. Another good option is looking out for phytochemical-rich food items containing naturally occurring senolytics, namely:
Tocotrienols and Quercetin Tocotrienols are a member of the vitamin E family, while quercetin is a natural flavonoid found in many fruits, vegetables, and grains. A report from Current Drug Targets states that these two phytochemicals have senolytic properties, which can rejuvenate pre-senescent and senescent cells. Tocotrienols are found in palm oil, rice bran, and barley, while quercetin is abundant in apples, onions, berries, and leafy greens. Fisetin
Fisetin is also a natural flavonoid found in fruits and vegetables such as strawberries, apples, persimmons, and cucumbers. Medical studies show that fisetin induces apoptosis in zombie cells by inhibiting the pro-survival mechanisms.
Pentadecanoic acid
Pentadecanoic acid is an odd-chain saturated fatty acid that removes harmful dormant cells by activating AMP-activated protein kinase (AMPK) and inhibiting the mTOR pathway.
Natural sources of pentadecanoic acid include dairy fat, ruminant meat, and salmon fish.
Does Exercise Get Rid of Zombie Cells?
The junk food or fast food diet we all love has been found to substantially increase markers like p16 and senescence-associated β-galactosidase that help the zombie cells proliferate. However, a mice study found that regular exercise can mitigate the effects of a high-fat, high-carbohydrate diet and prevent the build-up of the aforementioned inflammatory markers.
Does Fasting Get Rid of Zombie Cells?
Since aging cells are vulnerable to sugar deprivation, calorie restriction and periodic fasting, such as intermittent fasting, can cause a zombie cell's death. Human and animal studies show intermittent fasting promotes autophagy and reduces inflammation and oxidative stress linked to cellular senescence.
We will all age, but how we age is up to us. Our goal should be to promote 'healthy aging' rather than 'anti-aging.' Apart from adopting a healthy lifestyle and dietary habits, I would also strongly advise you to add topical antioxidants like vitamin C, ferulic acid, and vitamin E, as well as skin renewal agents like retinoids and peptides, along with regular sunscreen use to prevent oxidative stress on our skin cells.