Can we stop death?
"We could be immortal"
The fact that we age seems to be one of the uncomfortable things we take for granted in life. But even Michel de Montaigne expressed his doubts about this. The French essayist called it “unusual luck” to get old, because “to die of old age is a rare death” - very few people in Montaigne's 16th century, plagued by violence and epidemics, were granted it.
Today scientists are questioning whether it is really inevitable that we will deteriorate physically and mentally. Elisabeth Blackburn is one of the pioneers of such research.
Born the second of seven children in a remote small town in Tasmania, she studied biochemistry at Cambridge. Since then she has been studying the genetic mechanisms of aging. For this she received the Nobel Prize in 2009.
In her laboratory at the University of California in San Francisco, the now 63-year-old researcher talks about her discoveries as enthusiastically as if she had just made them. Only their own laughter can slow the flow of speech. In moments like this, you get the feeling that there is an even greater tenacity behind Blackburn's humor and her great friendliness. She owes her gentle stubbornness not only to her career, it also led to President Bush having the then world-famous scientist thrown out of his bioethics council in 2004 - a scandal that has never been seen before.
Dr. Blackburn, you dedicated decades of your life to the ciliates. What is so fascinating about these unicellular organisms?
They are wonderful creatures. They can reproduce asexually by simply doubling an animal. Nevertheless, there are seven genders who have children in pairs. And sometimes even three ciliates team up to reproduce together. One wonders why we are content with being women or men. Especially since ciliates, regardless of gender, can choose from seven different types of mating. That's wild! How can one not love these organisms?
Did you suspect that your research on ciliates was about to solve the mystery of human aging?
No. We wanted to study basic questions in molecular genetics. That was exciting enough: in 1975 my future husband and I were among the first people who could even read genetic information. Ciliates did well for these experiments. As we progressed over the years, we thought we were gradually penetrating the heart of biology. But my goal was never to heal human aging.
But if you look through the newspaper reports about your Nobel Prize in 2009, you might think that you have succeeded in doing just that. Didn't you find the hype excessive?
Not at all. For a long time I could not believe that our discoveries about ciliates could be transferred to humans. But now we have unequivocal evidence.
Ciliates are immortal.
This is also where the beauty of their biology lies: These unicellular organisms can divide infinitely often.
And so start a new life over and over again.
We asked ourselves how do you do it? The problem is: the chromosomes, the carriers of genetic information in the cell, lose a piece with each division.
At some point they become too short and the organism can no longer function.
This is exactly what the ciliates prevent with a fantastic, well-functioning repair mechanism. My then doctoral student Carol Greider found proof of this on Christmas Day 1984: There is a substance in the cell nucleus of the ciliates that can build up the chromosome ends again and again.
An elixir of immortality ...
... for the cell. We called this substance "telomerase". It helps to rebuild a kind of protective cap on the chromosome - the telomere. The eyelash animal owes its infinite life to this.
Our body can also regenerate. The Organs rejuvenate because their cells also divide, so to speak, to create their own successors. Unfortunately, this does not happen as often as you like with humans.
Exactly. Over the years, more and more cells die without replacement. Then the body functions slow down. But humans also have telomerase. A good ten years ago, colleagues discovered families whose members do not produce enough telomerase due to a hereditary disease - and who suffer from old-age disorders at an unusually early age. This proved that telomerase also delays aging in us.
Do these unfortunate people get demented early on?
Unfortunately, they don't have the time to do this. They die beforehand of cancer and all sorts of infections - as if their immune system was simply running out of steam. Apparently it has to do with the fact that the telomeres are getting too short. Since that discovery, we have seen a true tsunami of knowledge about the relationship between aging, disease and the length of the telomeres.
As if there really was something like a thread of life inside every cell. In ancient mythology, this determines not only the length, but also the quality of our life.
A nice picture. But the development does not always go in the direction of decay: Occasionally telomerase causes the telomeres to grow again.
In the legend, the goddesses of fate add something to the thread of life. But what does it really depend on how well our cells regenerate?
Living conditions play an important role - especially chronic stress. Together with psychologists, we examined the mothers of disabled children. Because they hardly get any support here in the USA, they are under enormous strain. And the more years they cared for their children, the shorter their telomeres, as a rule, were. We found something similar in people who had experienced traumatic events as children, such as the death of a parent or even sexual abuse. The more terrible experiences they had to endure, the more, again on average, their telomeres had shrunk.
As if every stroke of fate cut something off the thread of life.
The early stresses seem to leave particularly deep marks in the cell nucleus. The results make one thing very clear: how urgent it is to protect the children. However, there are people who can cope with even great hardships surprisingly well.
Apparently how long we live is also hereditary.
Yes. A fantastic proof of this is the Gotha, the German aristocratic almanac. It shows the life spans of around 45,000 highborn daughters from all over Europe; There is little to do with the dates of the sons, too many of whom died in the war. Women, on the other hand, almost always had a comfortable existence as long as they survived the puerperium. If one compares the age they reached with that of their parents, one makes an astonishing discovery: Until about the 75th year one has little to do with the other. Anyone who dies by then was caught accidentally by an illness or an accident. But those who make it past their 75th birthday owe it to their genes: These aristocrats usually had particularly long-lived ancestors.
But we all get more and more in the position of these higher daughters! Thanks to good hygiene and medicine that even queens could not hope for in the past, most people easily turn 75. So do genes set a natural limit in our lives?
We may be the first generation to find out. Because we live in an environment that has never been so protected before. Our organism was not shaped on this during evolution. Many people still die of cardiovascular diseases, but the number is falling: Heart attacks can be avoided by adopting a healthier lifestyle. Whether this also applies to the other big killer, Cancer, is an open question. How far human life expectancy can be increased is a huge experiment. And we are all the experimental animals in it.
What is your guess?
The current gene pool of our species apparently allows 120 years. The oldest person so far was Jeanne Calment from the south of France. She learned to fencing at the age of 85, rode a bicycle when she was a hundred and died in 1997 at 122. As with most over-centenarians, her relatives grew very old. And she enjoyed the best of health all her life - and she smoked like a chimney!
What did she die of?
It is unknown. Perhaps their death had no particular cause, as with so many very old people: at some point the whole system simply becomes unstable. Then all it takes is a small fall or pneumonia and you die. The death certificate then says "heart failure". As a doctor, you are always right.
Medicine usually assumes that disease, not old age, is the cause of death. They claim the opposite.
What do we actually mean by the word "disease"? It means different things: On the one hand, there is the suffering with a clear trigger. We are hit by some bacteria or virus and the symptoms set in. This is where medicine celebrates its great success. But on the other hand, there is such a thing as cardiovascular diseases, cancer or adult diabetes. They arise from the organism itself and build up over a long period of time. Today, doctors can usually only help to live with these ailments - if at all. Because our medicine looks too closely at the symptoms. The diabetologist tries to deal with your diabetes, the internist with the arteriosclerosis, and so on. But the reason for these diseases is more general: Apparently, the body's own repair mechanisms are failing.
And with your research you want to open up access to these ailments.
Which would be?
The three big killers - cancer, cardiovascular disease, and pulmonary disease - are clearly related to the condition of the telomeres. To understand this more precisely, we have teamed up with a large American health insurance company. Together we sift through the medical histories and habits of 100,000 insured persons over 65, analyze their genes and measure their telomeres. In this way, we want to find out which lifestyle and which genetic makeup means which stress on the body.
The insured do not oppose the fact that their insurance company examines them from the ground up?
On the contrary: people already ran down the doors for us during the preliminary studies in order to be able to participate. Some brought their résumé over personally. Others let us know that they were particularly scientifically interesting because of their daily yoga practices. They all wanted to find out how their telomeres were doing.
Do you like the role of the modern palm reader who predicts the time of death for people?
But nobody will find out from me! The length of the telomeres is only statistically representative of a certain life expectancy - just as one with a high blood lipid value is more likely, but by no means necessarily, to have a heart attack. Unfortunately, many people find it difficult to understand statistics.
Because they are understandably not very interested in how many out of a hundred patients with a certain telomere length are still alive after five years. They want to know their own fate.
Especially since it is so seductively clear to imagine that the length of the telomeres simply corresponds to the biological age!
You co-founded a company that wants to offer such tests to everyone this year. Why?
Because there is a demand for it. Our university laboratory could no longer cope with the inquiries, so everything began. And now someone has to be the first to go public. Rather, we do it well than others do it badly. That is why you will not be able to send in your sample yourself, but only through your doctor.
What do I get if I do it?
You get information about your body ...
… with which, unfortunately, there is little to do with. You have only just begun researching what exactly the state of the telomeres means for health.
We're not saying we know the answers either. Everyone who takes part should know that their data is used for ongoing research.
If you get tested, you risk a result that can be extremely stressful. Would you want to know that there is a 90 percent chance you will die in the next five years?
We also carried out a preliminary study: Nobody seemed to care about their test results. Experience with other genetic tests also shows that people know how to handle the results surprisingly well. If you have short telomeres, it's just a warning sign to take a closer look - like when the red low oil light on the dashboard comes on.
As adults, can we do something to reverse - or at least stop, the breakdown of telomeres?
Our studies on this are still at the beginning. At least one thing can be said: people who move more and sleep better have longer telomeres.
Do you know the length of your telomeres?
Yes. I am not worried. I am fine.
Has the result changed your way of life?
No. I try to move for half an hour every day anyway. This is the only silver bullet against physical decline that I accept. The data situation for this is overwhelming.
Just sport? You are a minimalist. Not to mention the billion dollar business with dietary supplements, a whole bunch of recipes against aging are also being traded among scientists: avoiding sugar, red wine, vitamin E, green tea ...
Everyone tries what seems helpful to them. But unfortunately no one was ever able to prove the effects. Nobody understands how the supposedly beneficial substances in red wine and green tea, the polyphenols, really work - and whether at all. You can get cancer from vitamin E in large amounts. It makes sense to use sugar sparingly. But the quality of life also counts for me.
You are 63. Don't you mind the signs of age?
I think my age is excellent. When I was your age ...
… 46 …
... I was the mother of a toddler. At the same time, my research occupied me completely. I felt terribly stressed. I also have another look at the world today. I wouldn't want to swap - even if I skied better back then.
Many people find it shameful that their skills are deteriorating and they no longer look like they used to. Women especially suffer from it.
But it doesn't have to be that way. Women can experience a second spring when the children are out of the house. However, they need support for this. Unfortunately, it is still common in our society to disregard older women.
You personally will find it hard to complain about the honors you came to.
In the USA you are not such a rarity as a Nobel Prize winner - as a Nobel Prize winner you are rather. When I perform in public, a lot of people get excited and want their daughter or grandchildren to see me. Just the fact that I exist proves for her: It is possible to create something like this. So at some point I realized that I don't have to do anything to be useful. It is enough to stay alive.
Would you like to be 120 or even 200 years old?
Oh yeah! However, you have to say what age you want to extend. I happily do without increasing the years between 80 and 90. Most people would like to extend the time between 20 and 30.
Not me. Too much heartache.
On the other hand, we are at the peak of our mental performance in these miserable years. If I really think about it, with a 20 year old brain I would want to start over again and again. First I would do what I did again for 25 years. Then I would try to study math thoroughly and go into cosmology. There are so exciting open questions that I often ask myself why are you wasting your time on biology. I would play the piano more often. And a lot more skiing.
The chairman of the American Bioethics Council, of which you were a member, called such dreams monstrous. Because it is precisely the transitoriness that has brought about the best aspects of human beings: dedication, seriousness, attachment to parents and children. What did you reply to him?
That the brevity of life is damn impractical. The colleague suspects that people with the prospect of more years will become lazy. But can he prove it? In any case, I don't see what suggests a lack of seriousness in my idea of three successive careers. However, I am not saying that my model will fit everyone. Some people worry that they'll have to be married to the same person for 180 years!
The question is, what is the point of aging?Turtles, for example, are spared this fate.
In which sense?
Even a specialist cannot tell the difference between the organs of a young and a hundred-year-old turtle.
Apparently these amphibians have extremely powerful repair mechanisms. Various reproductive strategies have proven themselves in evolution: Either one reproduces, especially at a young age, like us.Then living longer does not bring any biological benefit. Or an animal, like the turtle, can produce offspring until death. Then every year more means a profit. However, it costs the organism a lot of energy to constantly counteract the decline.
Food may have been scarce for our ancestors, but it is not for us. Would it be conceivable to improve the human metabolism in such a way that we no longer age either?
Basically yes. The only question is whether our cellular machinery is sufficient for this. The system we are born with may come to a point where nothing can be teased out.
Where can it be?
We do not know that. I'm on the advisory board of an initiative called Tara Oceans, which wants to study all life in the ten meters below the surface of the sea. You can find the most amazing things there: copepods, for example, with incredibly well-functioning repair systems. Although they are multicellular, some of them could even be immortal.
It is not a law of nature that higher life approaches death.
Do you fear him?
No more. My son is grown up. I would feel sorry for him and my husband if I left. But many good things have happened in my life. Why should I fear death then?
published in: Zeit-Magazin 17/2012
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