In the battle against aging, one enemy simply refuses to die. Scientists call it the “zombie cell.” Killing zombies may be the key to treating the myriad problems elderly people experience.
The actual scientific name for zombie cells is “senescent cells.” Senescent refers to the process of becoming old. Christians shouldn’t be discouraged by being senescent—because “though our outer self is wasting away, our inner self is being renewed day by day.” (2 Corinthians 4:16)
Zombie or senescent cells start out normal but then encounter trauma, like damage to their DNA or a viral infection. When that happens, cells either die or become “zombies”—that is, suspend their normal functions and start causing trouble.
Studies suggest that as zombie cells amass, they promote aging and other conditions like osteoporosis and Alzheimer’s disease. Instead of playing a “whack-a-mole game” of treating one age-related disease only to see another spring up, scientists want to fight aging itself, says geriatrics specialist James Kirkland.
When aged mice received drugs targeting zombie cells, the animals showed better walking speed, grip strength, and endurance. That was true even in very old mice, the equivalent of people aged 75 to 90. Getting rid of zombie cells also seems to improve conditions such as cataracts, diabetes, osteoporosis, Alzheimer’s, kidney problems, and clogged arteries. In fact, zombie-killing drugs extended lifespan by an average of 36% in mice.
Surprisingly, the reverse also proved true. Transplanting zombie cells into young mice made them act older: Walking speed slowed, and muscle strength and endurance decreased. The implanted cells actually altered healthy cells into zombies.
So far, researchers have worked mostly with mice. But earlier this year, Kirkland and colleagues published the first study of a zombie-cell treatment in people. It involved 14 patients with an often-fatal disease that scars the lining of the lungs. In each case, the lungs of the patients showed evidence of zombie cells.
Given the zombie-killing drug, patients improved on some measures of physical fitness, like walking speed. Other measures, however, did not show improvement.
Still, the results are encouraging. And what about giving anti-zombie drugs to healthy people who want to avoid aging? It’s possible, believes Laura Niedernhofer of the University of Minnesota, but it’s a long way off. After all, in the anti-aging field, zombie cell treatments are young. Researchers working toward a cutting-edge cure haven’t yet decided whether the drugs are safe in the long term.