Human heart muscle cell renewal
The conventional wisdom has been that cell division in heart muscle cells (cardiomyocytes) stops at or shortly after birth and that the cardiomyocytes of an 80 year-old are the same ones he started out with. The technology of radioactive carbon-dating has been recently applied to study this issue and shows that this conventional wisdom is wrong. Heart muscle cells are slowly but constantly renewing throughout life.
Radioactive carbon-dating has long been used as the primary technology for establishing the age of archeological artifacts. A recent study applied radioactive carbon-dating based on carbon-14, generated by nuclear bomb tests during the Cold War to analyzing the issue of heart muscle renewal. The study looked at the integration of carbon-14 into human cardiomyocyte DNA to establish the age of cardiomyocytes. Nuclear bombs were tested above-ground between 1955 and 1963. So, looking at the carbon-14 content in cardiomyocyte DNA from people born before 1955 it is possible to tell how many are original and the rate of cardiomycyte renewal.. “We report that cardiomyocytes renew, with a gradual decrease from 1% turning over annually at the age of 25 to 0.45% at the age of 75. Fewer than 50% of cardiomyocytes are exchanged during a normal life span.” So, when someone reaches the age of 50, about 55% of his or her heart muscle cells date back to birth and the rest are newer(ref).
The study is interested in that it opens the possibility for interventions that greatly accelerate the rate of renewal of heart muscle cells. Such could be useful for treating a number of cardiac pathologies and for helping extend the working lifetimes of hearts.
About Vince Giuliano
Being a follower, connoisseur, and interpreter of longevity research is my latest career, since 2007. I believe I am unique among the researchers and writers in the aging sciences community in one critical respect. That is, I personally practice the anti-aging interventions that I preach and that has kept me healthy, young, active and highly involved at my age, now 93. I am as productive as I was at age 45. I don’t know of anybody else active in that community in my age bracket. In particular, I have focused on the importance of controlling chronic inflammation for healthy aging, and have written a number of articles on that subject in this blog. In 2014, I created a dietary supplement to further this objective. In 2019, two family colleagues and I started up Synergy Bioherbals, a dietary supplement company that is now selling this product.
In earlier reincarnations of my career. I was Founding Dean of a graduate school and a full University Professor at the State University of New York, a senior consultant working in a variety of fields at Arthur D. Little, Inc., Chief Scientist and C00 of Mirror Systems, a software company, and an international Internet consultant. I got off the ground with one of the earliest PhD's from Harvard in a field later to become known as computer science. Because there was no academic field of computer science at the time, to get through I had to qualify myself in hard sciences, so my studies focused heavily on quantum physics. In various ways I contributed to the Computer Revolution starting in the 1950s and the Internet Revolution starting in the late 1980s. I am now engaged in doing the same for The Longevity Revolution. I have published something like 200 books and papers as well as over 430 substantive.entries in this blog, and have enjoyed various periods of notoriety. If you do a Google search on Vincent E. Giuliano, most if not all of the entries on the first few pages that come up will be ones relating to me. I have a general writings site at www.vincegiuliano.com and an extensive site of my art at www.giulianoart.com.
Please note that I have recently changed my mailbox to email@example.com.
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Enjoyed you informative piece on heart cells.
I have been researching the ramifications of increasing body size for over 3 decades. I started out using the 2nd law of thermodynamics as my guide to the aging process. My application of this law to human longevity was based on the hypothesis that increased mass and energy increases entropy and accelerates aging. Since then I have published many papers and a two books on the negative aspects of increasing body height and associated weight which are currently viewed as a good thing by most medical and nutritional experts, including economist and nobel prize winner, Robert Fogel.
If you are interested in this area of research, check out my website: http://www.humanbodysize.com
The site lists a number of my publications.
I was not familiar with your past work or book but find it interesting, being a physicist by early training. As I see it, however, there is something screwy about our classical views of entropy and the Second Law of Thermodynamics. The problem is that it can be applied only very narrowly:
1. From a cosmological perspective, just after the big bang there was only pure energy nothing was differentiated from anything else. Out of this evolved a highly ordered universe with galaxy clusters, galaxies, suns, planets, laws of physics, chemical elements and laws of chemistry, living organisms, biology and society. There is now a very great deal of system and organization that started from none, all opposite of what the Second Law says happens.
2. From a biological perspective, living organisms represent very low entropy systems. We have an incredible amount of internal order. Even though the impact on the environment of biological organisms is increase of overall entropy. How this happens is far beyond the scope of the 2nd Law. In fact, so is evolution itself.
Without question the Second Law holds for a closed volume of gas not in thermodynamic equilibrium and we never see smoke in the sky gathering up and going down smoke stacks, but in the large in the world we live in the Law seems not to hold. And this seems to apply on multiple levels. Information as you know is negative entropy, so the increasing volumes or information being produced by our society represents a decrease in entropy. So is this dialog.
That all said, I think you are right in one respect. Big heavy people consume more food, produce more waste and tend to increase overall entropy more. So do whales and elephants, but evolution in its wisdom produced those creatures as well as microbes, mice and us. Enough said! I will have to look at your book before I can respond more speciically to your hypothysis about size, thermodynamic deterioriation and aging.