A recent New York Times article entitled “How long can we live” provides a good summary of evidence behind the scientific debate that speculates about the limits of human lifespan, and the potential consequences of altering our inheritable biology. The first validated cases of supercentenarians, people who live beyond their 110th birthday, emerged in the 1960s. Since then, we’ve seen a tenfold increase in their numbers. Japan’s population of supercentenarians grew from 22 to 146 between 2005 and 2015. Yet, the record for the longest life span is still held by Jeanne Calment, who died at age 122 in 1997. The person who came closest was Sarah Knauss, dying at age 119, in 1999. (Check out this photo of Sarah and six living generations in her family.) In other words, nobody’s come within three years of the record in almost a quarter of a century.
Have we already witnessed the limits of human life span? This article digs into the debate over this question and ponders the implications if the answer is “no.” I recently discussed this question with someone mentioned in the article, Steve Austad, and our conversation will come out August 9th. Steve bet a fellow expert on longevity in the year 2000 that there will be one or more 150-year-olds by the year 2150. (A recent article from Scientific American reported on new research suggesting Steve could be right.) I also discussed related questions and issues with Matt Kaeberlein, who was a previous guest of the podcast and returned for a second podcast that will be released mid-September.
As I alluded to in an email a few weeks ago, at the request of many of our listeners we are experimenting with taking off one new episode release per month during the summer to give listeners a chance to catch up. As such we will not have a new episode come out tomorrow. While the complete episode archive is always available to help the selection process, I have selected three episodes for you to (re)visit pertaining to life-extension research. I thought highlighting a few conversations that have been instrumental in my edification on geroscience would be apropos, given the NYT article above.
My conversation with David was one of the first discussions I had with a guest about the mechanistic target of rapamycin (mTOR). In fact, the dialogue was originally recorded as a book interview to inform a chapter of my book (pre-podcast era!) but was so good we made it a podcast episode once we started The Drive. This episode is a great place to start in the rapamycin saga and its proven ability to extend lifespan. We start at the beginning, with the discovery of rapamycin in 1972, discuss how the pharmaceutical agent works, and its effects on cancer, cardiovascular disease, and neurodegeneration. David and I will be sitting down again in the coming months to discuss the latest research coming out of his lab.
My initial conversation with Matt, similar to that with David, was a recording to inform my book a few years back. Matt also studies the effects of rapamycin on lifespan and healthspan, primarily in his research with dogs through the Dog Aging Project. We discuss rapamycin’s ability to suppress the immune system and provide immune-enhancement, as well as the drug’s anti-cancer effects when given at the right dose.
Something Rich said during our conversation really stayed with me. He said: “What I care about is: What is the process that can postpone all the different aspects of aging?” Rich always wanted to work on research that could uncover the mechanisms of aging, dispelling the myth that aging cannot be slowed. With his colleagues, Rich put together a proposal to start the Interventions Testing Program (ITP) as part of the National Institute on Aging. Rich has been instrumental in constructing a scientific framework by which life-extending drugs are tested, beginning with model organisms. This is a great episode to help organize one’s thinking about what aging is, asking the right questions, and what rigorous scientific inquiry looks like.