Japanese researchers have tested out a vaccine in mice that appears to prevent the accumulation of zombie cells, scientifically known as senescent cells, which are usually associated with aging and several diseases. While it might be a stretch to call this development a “vaccine against old age,” the vaccine could eventually prove useful for the prevention of certain age-related diseases.
Senescent cells are normal cells that have stopped multiplying but don't die. Instead, they stick around like “undead zombies” and release chemicals that can trigger inflammation in surrounding healthy cells. Senescence can be caused by a number of factors, including the general wear and tear of the cell's genetic material that occurs with each successive division, as well as wider DNA damage. A 2011 study found that eliminating these senescent cells delays age-related illnesses and later studies confirmed that removing them can alleviate, and perhaps even prevent, certain illnesses.
As reported in the journal Nature Aging, scientists at Juntendo University in Tokyo, looked to remedy this problem by developing a vaccine that stops senescent cells from accumulating.
The researchers identified a protein found in the senescent cells of humans and mice. They then used this information to create a peptide vaccine that triggers an immune response against the protein. Much like a vaccine against a virus or a bacteria, the vaccine will "train" the body's immune system to create antibodies that will recognize a specific antigen found on the protein of the senescent cells and eliminate them.
To test out the vaccine, the team carried out an experiment on mice suffering from arteriosclerosis, a thickening and hardening of the walls of arteries often seen in old age. Not only did the vaccine improve the mices’ arteriosclerosis, but the study’s conclusion also explained that it had improved “normal and pathological aging in aged mice and prolonged the lifespan of mice with premature aging.”
“We can expect that (the vaccine) will be applied to the treatment of arterial stiffening, diabetes and other aging-related diseases,” professor Toru Minamino, study author from the Juntendo University Graduate School of Medicine, told the Japan Times.
Once again, however, it would be naive to think this vaccine could be the foundation of eternal youth. Firstly, the research is only in its early stages and the vaccine has only been carried out in mice. Secondly, cellular senescence isn’t the only hallmark of aging. Along with the accumulation of “zombie cells,” aging people will also experience telomere shortening, genome instability, epigenetic alterations, stem cell exhaustion, and other biochemical signs of aging. Senescent cells, therefore, are just one part of the puzzle.