As one of the authors of the initial SENS position paper, published many years ago now, Judith Campisi is one of the small number of people who is able to say that she was right all along about the value of targeted removal of senescent cells, and that it would prove to be a viable approach to the treatment of aging as a medical condition. Now that the rest of the research community has been convinced of this point - the evidence from animal studies really is robust and overwhelming - the senescent cell clearance therapies known as senolytics are shaping up to be the first legitimate, real, working, widely available form of rejuvenation therapy.
Why should we suddenly get excited about anti-aging drugs again?
There are now tools available to biomedical scientists that simply didn't exist when I was a graduate student or even a postdoc. So we're finally able to do experiments that were either considered impossible in some cases or were just dreams 20 or 25 years ago. The other thing that has changed is that the field of senescence - and the recognition that senescent cells can be such drivers of aging - has finally gained acceptance. Whether those drugs will work in people is still an open question. But the first human trials are under way right now.
How specifically does senescence contribute to aging?
The correct way to think about senescence is that it's an evolutionary balancing act. It was selected for the good purpose of preventing cancer - if cells don't divide, they can't form a tumor. It also optimizes tissue repair. But the downside is if these cells persist, which happens during aging, they can now become deleterious. Evolution doesn't care what happens to you after you've had your babies, so after around age 50, there are no mechanisms that can effectively eliminate these cells in old age. They tend to accumulate. So the idea became popular to think about eliminating them, and seeing if we can restore tissues to a more youthful state.
You've suggested that health care could be transformed by senolytic drugs, which eliminate senescent cells. That's a pretty broad claim.
If we think of aging as a driver for multiple age-related pathologies, the idea would be that a new generation of physicians - we call them geriatricians today - will take a much more holistic approach, and the interventions will also be more holistic. That's the idea-it would revolutionize the way we're thinking about medicine nowadays. And just to remind you, 80% of patients in the hospital receiving acute medical attention are over the age of 65. So the idea is that senolytics would be one weapon that geriatricians will have in their arsenal of weapons to treat aging holistically as opposed to one disease at a time.