Eminent biomedical researcher Leonard Hayflick died on August 1, 2024, at age 96. He was best known for his pioneering research on telomers, the piece of DNA that diminishes when normal cells replicate. He determined that the telomere disappears after about 50 replications of normal human embryonic cells, resulting in cell senescence and death. Fifty replications occur over a maximum of about 120 years This phenomenon came to be known as the Hayflick Limit for the human lifespan.
Hayflick was an outlier who relentlessly criticized aging research for emphasizing treating and curing diseases while investing little in basic molecular and cellular research. He insisted that common factors at the molecular and cellular levels underlying diseases associated with aging could provide answers leading to the cure of all age-related diseases including Alzheimer's.
In 2016 I interviewed Hayflick for an article titled On the Verge of Immortality or Are We Stuck with Death? He passionately exclaimed "Why in the hell aren't we studying the fundamental biology of aging if that is the major risk factor for age-associated diseases? Why are we ignoring it almost 100 percent?"
When I praised him for his discovery of the Hayflick limit he fired back, "I never said that." I was stunned. By then the Hayflick Limit was well-known in scientific circles. Was its creator denying it now?
After gathering my thoughts, I asked him why there isn't a Hayflick Limit since the telomere vanishes after 50 replications. Doesn't that imply a limit to the human lifespan? Almost every researcher proposing to extend the human lifespan begins with the question: Is it possible to exceed The Hayflick Limit? Microsoft Edge currently lists nearly 300,000 references for The Hayflick Limit.
Here is the transcript of my recorded interview with Leonard Hayflick on his denial of a Hayflick Limit:
Starr: There are hundreds as you well know maybe more articles about you that talk about the Hayflick Limit setting longevity at about 120 years.
Hayflick: No, That's absolutely spurious. I've never seen that in print before. If it has occurred it has occurred maybe once or twice but it's absolutely wrong.
Starr: Oh no, it's in hundreds of articles.
Hayflick: Hundreds of articles are wrong which is not unusual. In the past fifty years, I have never seen an article about my work that was accurate. If this is included in hundreds of articles it's dead wrong.
Starr: OK. If it's wrong it's wrong. You have the last word in this.
Hayflick: It has to be corrected. It did not set human longevity at approximately 120 years. I would like to see the data that supports that phrase. Give me one example.
Star r: When I submit this [article] to an editor and it says the Hayflick Limit based on the 50 replications of cells the question the editor will ask, "Then what's the limit?"
Hayflick: That editor needs to be educated in biology That's my response. It's a stupid editor who wants to hype the article and I'm unwilling to hype my work.
Starr: The editor would say if we are going to talk about life span, life expectancy, and there's a limit, what limit are we talking about"what are the parameters?
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