What Are Zombie Cells and How Are They Linked to Ageing?

It’s a fact of life: If you’re lucky enough, you will get older and, with that, your body will show signs of ageing. Research has been ongoing to try to determine what, exactly, is behind this process and scientists have largely linked the ageing process with one biological factor: Senescent cells, aka zombie cells.

A recent study published in Nature Structural & Molecular Biology specifically links zombie cells to age-related diseases like cancer, dementia, and heart disease, and breaks down how these cells develop.

The study found the oxidative damage (damage that happens as a result of an imbalance between free radicals and antioxidants in your body) to telomeres, the protective ends of chromosomes, can spark the formation of zombie cells.

This isn’t the only research on zombie cells: Scientists have been analysing these cells and their role in ageing for years.

If you’ve never heard of zombie cells before, fair. But, of course, you probably have some—or a lot of—questions about what these are and what role they play in ageing. Here’s a breakdown.

What are zombie cells?

It’s important to quickly recap how cells in your body work. There is a process called mitosis, which is a fundamental process for life, where a cell duplicates all of its contents and splits to form two identical cells, Medline Plus explains. When mitosis isn’t regulated correctly, you can develop health problems like cancer.

Zombie cells, aka senescent cells, are cells that stop dividing, according to the National Institutes of Health (NIH). When you’re younger, your immune system spots these cells and eliminates them from your body, GP Dr Sabrina Barata explains. But, as you get older, your immune system doesn’t have as large of a capacity to do this.

What do zombie cells do?

Zombie cells simply stick around in your body. “They don’t die—they become resistant to death,” says researcher and biology expert Dr Paul Robbins. “They stay in your body forever.”

These cells release certain molecules that can spark inflammation and even harm other cells, Dr Robbins says. They’ve also been linked to the growth of cancerous cells, per the NIH.

However, Dr Robbins says, senescence is seen as an anti-cancer mechanism because it stops cells that may have become abnormal from continuing to replicate.

Does everyone have zombie cells?

“I would hypothesise that yes, everyone has these cells,” Dr Robbins says. “Your burden of cells increases with age and older people or people with chronic diseases may have more.”

Cells stop dividing after they’ve divided so many times or acquire so many mutations that they’re at risk of becoming abnormal or potentially making you sick, the NIH says.

How are zombie cells related to ageing?

Zombie cells become more common as people age. “Your immune system gets rid of these cells when you’re young but, when you get older, it can’t clear them as effectively,” Dr Robbins says. Research has found that tinkering with these cells can help extend life—in mice, at least.

Could studying zombie cells be the key to living a longer life?

That’s what doctors think right now. “If we understand why senescent cells happen and how to reverse them, we have the ability to have healthier ageing with less debility,” says neurologist Dr Santosh Kesari.

Dr Robbins points out that zombie cells are “interconnected” with other “things that go wrong as we age.” Those include things like dysfunction in your stem cells, changes in metabolism, and dysfunction of your mitochondria, which generate energy to power your cells, he says.

“If one of these things are affected, the others are, too,” Dr Robbins says. “They’re all linked.” Meaning, if you can target and wipe out zombie cells, your metabolism and energy may improve, he says.

Dr Barata says that studying these cells can “absolutely” help lead to advances in healthy ageing. “If we can find a way to kill off these cells, they won’t accumulate in the body,” she says. “That will protect us from diseases like dementia, certain cancers, and cardiovascular disease.”

Currently, research is ongoing to study the impact of targeting zombie cells and certain diseases like Alzheimer’s disease, osteoarthritis, and diabetes. “We will know their impact quickly—within in a few years,” Dr Robbins says