Sewing old and young mice together. Killing crabby zombie cells (but not all of them). A biotech CEO who becomes a guinea pig for her company’s anti-aging gene therapy. And the amazingly long lifespan of ... squirrels.
These are all parts of what Tina Hesman Saey, molecular biology writer at Science News, discovered in the course of writing her new story “Slowing Time,” part of the new “Aging’s Future” issue of Science News.
Below, go behind the story in this Q&A with Tina to find out whether we’ll ever live forever, why she pushed so hard to cover the science of aging, and how long Rocky can really live.
WHAT IS AGING, REALLY: Nobody agrees — certainly not at the molecular level. I went on a reporting trip to the Buck Institute for Research on the Aging expecting somebody there to have the answer, and it’s like, oh no! Scientists are all very passionate about their own views — and equally passionate in dismissing other scientists’ views.
SO WHY SEW TWO MICE TOGETHER: It’s called a parabiosis experiment. You surgically stitch together two mice so that their blood supplies grow together.
When you stitch together an old mouse and a young mouse, it rejuvenates the old mouse. Its memory gets better, it’s easier for its muscles to heal, it’s spry again and has all this energy. But the young mouse doesn’t fare so well — it starts to age prematurely.
This indicates that aging isn’t just a passive buildup of random damage, but an active process. It also suggests that, while everyone will grow chronologically older, we should theoretically — like the old mouse — be able to stave off the frailty and diseases that come with aging.
KILL THE WALKING DEAD (CELLS): Most of the anti-aging interventions I learned about aren’t about lifestyle changes, but exploring how to remove senescent cells. These are zombie cells that have shut down — they no longer divide, they no longer do the things that they used to do when they were young and vigorous. Instead, they send out all of these crabby messages — curmudgeon chemical signals into your blood to the cells around them, which makes those cells start to shut down too.
When you stitch together an old mouse and a young mouse, it rejuvenates the old mouse.
Now researchers are killing the senescent cells in mice and removing them from the body. That helps the mice live longer, healthier lives. That might also work in the human body — but you can't kill all of them, because it turns out they're needed in wound healing. Without at least a few of them, you'd never be able to heal a cut.
CAN WE LIVE CLOSE TO FOREVER ... SOMEDAY: Probably not, according to the science. We won’t live 500 years. We probably won’t live much longer than we do now. But we can be healthy pretty much up to the day we die.
THE CEO WHO LENGTHENED HER TELOMERES: Telomeres are the endcaps on chromosomes — they work like those little plastic things at the end of shoelaces to keep your chromosomes from unraveling at the ends. Longer telomeres are associated with longer life, and if they get too short, you’re in danger of having that cell die, getting disease, and dying yourself.
People have used short telomeres as a marker of aging — but one company seems to consider it a cause of aging. The company’s CEO is 45 years old, and she went to Colombia to undergo an anti-aging gene therapy they’ve devised to lengthen telomeres. But nobody knows if that’s going to make her healthier. Many say that she may have stabilized chromosomes that are damaged and could lead to cancer. She might actually die sooner because she’s done this.
MOST EXCITING AREA OF AGING RESEARCH: There are so many. The thing is, we don’t have the answer to what’s going to work against aging — and we don’t know if it’s going to work in our lifetimes.
Squirrels can live up to 30 years.
This isn’t a new problem. One researcher I was interviewing reached into his desk drawer and pulled out a napkin on which he and another researcher had put down their predictions 20 years ago about what was going to happen in aging research in the next 10 years. And basically none of their predictions have come true.
The promising research then was on mutations in mice and worms that made them live twice as long as they normally would — so the researchers thought we would have by now made humans live twice as long as well. Uh-uh.
TINA’S GOOD GENES: One of my grandmothers died at age 92. Up until a few months before her death of a brain tumor, she was still an Avon lady, and still walked five miles every day. She’d complained to me about a year before she died (she didn't know of the tumor) that she was slowing down — that it was taking her closer to an hour now to do five miles instead of 45 minutes.
But we all assumed it would be my grandfather who would die first, because he’d had a stroke and some health issues — but he’s 97 and is still hanging in there. It’s one of those mysteries of life.
WHY SHE PUSHED HER EDITORS FOR YEARS TO FOCUS ON THE SCIENCE OF AGING: Because the media has focused on longevity without any understanding of the processes behind aging and what's actually going on there — what the science is. I thought that was something that Science News could actually contribute to.
Aging is a very active area of research and has become even more so over the last 10-15 years, with a lot of studies in the last five years. The timing is right.
BIGGEST SURPRISE REPORTING THIS STORY: That squirrels can live up to 30 years. Now every time I see a squirrel, I wonder how old it is.