After all, if we can understand how some animals manage to bypass aging, that could be a first step toward using the same sort of strategy ourselves.
And that’s exactly what researchers are trying to do.
Worming Our Way Out of The Aging Trap
In a study at the University of Nottingham in England, for example, scientists have made great progress in understanding how a type of flatworm sidesteps aging and becomes immortal.[i] The worms – planarian worms – don’t get older. When their organs start to age, or their tissues are damaged, they effortlessly replace them with new-grown cells.According to researcher Aziz Aboobaker, the Nottingham group has been studying two types of these worms. One type has male and female members and reproduces sexually. The other is asexual and divides in two to make copies of itself.
Both types have no problem regenerating new skin, guts, muscles and even brain tissue over and over again, without end. In human terms, it’s as if every time you reached your fiftieth birthday, you turned back the clock and simply regrew yourself as a 20-year-old.
Not All Stem Cells Are Alike
Our stem cells wear out as we age and, as a result, we lose our ability to make repairs in the body with each passing year.As Dr. Aboobaker puts it, “This means that the stem cells are no longer able to divide and so become less able to replace exhausted, specialized cells in the tissues of our bodies. Our aging skin is perhaps the most visible example of this effect.”
But the worms don’t have that problem. “Planarian worms and their stem cells are somehow able to avoid the aging process and to keep their cells dividing.”
These stem cells remain immortal thanks to their regenerative telomeres. Telomeres are the protective end caps on genetic material that keeps it from getting damaged when cells divide.
In humans, aging stem cells wear out because their telomeres become so shortened over time they can’t protect DNA from damage. The stem cells then become non-functional or undergo apoptosis – programmed cell death. As a result, aging leads to a shortage of healthy stem cells. When that happens, damage accumulates in the body’s organs because the dwindling number of stem cells that are left can’t keep up with the repairs.
But the worms can maintain their stem cell telomeres with a continual supply of telomerase – an enzyme that regenerates their telomeres. In humans, this enzyme is not available to older cells. But the worms have an endless supply of this key to immortality. If we can learn to help our cells maintain more telomerase, we might also live longer.
Other Immortals
Scientists are also looking into how these other animals live long lives:- Turtles: Turtles never die of old age. They’ve been known to live for hundreds of years and their organs don’t seem to wear out.
- The Turritopsis dohrnii jellyfish revert to younger forms and regrow themselves when faced with problematic environmental conditions.
- The tuatara lizard of New Zealand keeps growing into its 30s. No one knows how long they can live, but one male sired offspring when he was 111.
Well, it seems a reasonable bet that if they can live for hundreds of years, researchers can find a way to make it happen for us, too.
