7 ms·

T cells block nerve cell regeneration with age, but can be reversed – mice study

141 points by mrtedbear 4y ago

rogerkirkness 4y ago
This feels like one of those - there is probably a reason for that - moments.
- TrainedMonkey 4y ago
  Possibly. Assuming yes, brings up a question of whether that reason still applies.
- kgc 4y ago
  Likely reduces incidences of cancer.
  - majidmir 4y ago
    Probably on both cellular and social scales
    - neuronic 4y ago
      The T-cells should up their ante then.
- oneoff786 4y ago
  Biological systems that include death as a feature propagate more effectively
  - throwawayboise 4y ago
    Yes, and death also enables reproduction without eventual overpopulation. Reproduction leads to mutation, which evolves the species.
  - TedDoesntTalk 4y ago
    So what about the Hydra and turritopsis dohrnii?
    - oneoff786 4y ago
      Local maxima of the fitness function
- Aperocky 4y ago
  The reason might not be for the health of the individual - as evolution emphasize reproductive fitness and not longevity. Evolution make individuals of a specie healthy and fit until they reproduce and raise their young, and after that the evolutionary pressure becomes negative (are now competing against offspring success in limited resources).
  - turtledove 4y ago
    This is notably prevalent in octopus, who are incredible creatures with short lifespans post reproduction.
  - cortic 4y ago
    One of the reasons we live so long is that the evolutionary pressure is not negative after reproduction; To begin with it takes 15+ years to raise human offspring to a stage where they might be able to fend for themselves. 20+ years to give them advantage in the environment. Grandparents relieving this burden for each generation greatly increases their reproductive success, far beyond procreation. This is of course similar to other animals, but the benefits are amplified by at least two major factors in humans. First the usefulness of inherited complex knowledge. And second, because of fetal underdevelopment due to birthing hip limitations in evolved bipedal locomotion.
    - throw827474737 4y ago
      Hm not true, a lot of other factors like medicine more relevant, would even say that modern human society has taken out almost all evolutionary pressure except for really bad conditions?!
      - klipt 4y ago
        Not at all, in fact modern society has added many new evolutionary pressures. E.g. by inventing birth control, society gave an evolutionary advantage to people who refuse to use birth control for religious reasons, or people whose biology is incompatible with birth control, e.g. a woman for whom the pill just doesn't work, is likely to have more children.
- jostmey 4y ago
  Perhaps not! Evolution does not select for longevity once enough time has elapsed for sufficient reproduction
- arcticbull 4y ago
  I mean, the female hyena gives birth through the clitoris. Not all evolutionary decisions are optimal for the individual. Some are just horrifying and weird.
  - Hedepig 4y ago
    This. Another example is the recurrent laryngeal nerve.
    - andai 4y ago
      >The extreme detour of the recurrent laryngeal nerves, about 4.6 metres (15 ft) in the case of giraffes, is cited as evidence of evolution, as opposed to intelligent design. The nerve's route would have been direct in the fish-like ancestors of modern tetrapods, traveling from the brain, past the heart, to the gills (as it does in modern fish). Over the course of evolution, as the neck extended and the heart became lower in the body, the laryngeal nerve was caught on the wrong side of the heart. Natural selection gradually lengthened the nerve by tiny increments to accommodate, resulting in the circuitous route now observed. https://en.wikipedia.org/wiki/Recurrent_laryngeal_nerve#Evidence_of_evolution https://en.wikipedia.org/wiki/Recurrent_laryngeal_nerve#Evid...
  - b112 4y ago
    https://www.hyaenidae.org/how-does-the-female-spotted-hyena-give-birth/ https://www.hyaenidae.org/how-does-the-female-spotted-hyena-... I just found this, reading up on your comment, and by god I hate SEO spam, and auto-generated docs.
- SemanticStrengh 4y ago
  Death is in part an evolutionary advantage. The thymus of humans self atrophy in order to kill the elderly
  - formerly_proven 4y ago
    > The thymus of humans self atrophy in order to kill the elderly [citation needed]
    - JPLeRouzic 4y ago
      2009: "There is an accumulating body of evidence that a decline in immune function with age is common to most if not all vertebrates. For instance, age-associated thymic involution seems to occur in all species that possess a thymus, indicating that this process is evolutionary ancient and conserved. ... we show that life history trade-offs play a key role and we highlight the possible advantages of the age-related decline in thymic function." https://www.cell.com/trends/immunology/fulltext/S1471-4906(09)00105-7 https://www.cell.com/trends/immunology/fulltext/S1471-4906(0... 2021: "The thymus begins to degenerate as early as the second year of life and continues through aging in human beings, leading to a decreased output of naïve T cells, the limited TCR diversity and an expansion of monoclonal memory T cells in the periphery organs. These alternations will reduce the adaptive immune response to tumors and emerging infectious diseases, such as COVID-19, also it is easier to suffer from autoimmune diseases in older people. " https://clinicalepigeneticsjournal.biomedcentral.com/articles/10.1186/s13148-021-01197-0 https://clinicalepigeneticsjournal.biomedcentral.com/article...
      - SemanticStrengh 4y ago
        Great links! You might be interested in my answer too
    - SemanticStrengh 4y ago
      > total loss of thymic reticuloepithelial tissue and the associated thymocytes should occur only at the age of 120 years in humans. The thymus involution is the most obvious hard limit for Ageing beyond 120 years old. At age 70 your thymus has 100% shutdown and the only T cell immune system you have left are the old one still remaining in your bloodstream) (the half life is of 17 years) The involution of the thymus (3% per year) has no consensual explanative theory behind it but the two main theories are: 1) a fact is that thymus involution appear by biologically controlled mechanisms, it appear too soon (teenage years) to be mainly due to a normal effect of an accumulation of damage (aging) although reducing oxidative stress reduce the rate of loss of thymus. Another fact is that it is universal among mammals, and since a long time it is a conserved evolutionary mechanism. Now I'd like you to appreciate for a minute how lucky we are and how absurdly kind life is with us. We are optimized for survival in a world with scarce resources. We should have developed atrocious mechanisms that would make the human condition deep shit for increased survival but we have mysteriously not. E.g after taking your meal of the day we should go into low energy consumption mode, have much reduced muscular and cognitive abilities) except in the presence of dangers/stressor, until the next day. As I said, mysteriously we are not too much behavioiraly optimized but that does not preclude that some mechanisms (especially ancient mechanisms) have been designed for hardcore resource contraints and therefore have surprising tradeoffs. The thymus is an energy consuming organ but it's not needed for medium term survival. Because the t cell it has produced will still work for the next 20-30 years. The age of reproduction in humans is well below 40 year old and evolutonarily speaking, a human leaving past its age of reproduction is an absurd inefficiency. It does not contribute much to the survival of the group and it consumes critical resources. It would often be logical to induce an instantaneous death to humans past a certain age (evolutonarily speaking). Many living beings, especially insects, die after reproduction, usually being eaten by the mother/childs. Again nature has been kind with us, but basically thymus involution is like killing you after the age of reproduction, except it's a very slow process that reach completude at 70 years old and absolute immune absence at 120. (note that this is only about T cells, the spleen (producing b cells) is another topic although it doesn't age well either). So yeah this theory it the most potent to explain why the thymus involute. Since this theory is a bit harsh for politics, researchers do not talk much about it. They fallback on a milder version where they simply say that the thymus in itself consume energy and reducing it allow for oleer people to consume less energy (or allocate it to other things) without addressing the obvious evolutonnary advantage of controlling lifespan. Their milder theory is probably true in conjunction with mine. A backing evidence of them is that testosterone reduce the thymus, possibly for resources competition. https://pubmed.ncbi.nlm.nih.gov/9427047/ https://pubmed.ncbi.nlm.nih.gov/9427047/ "Why does the thymus involutes?" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3295077/#:~:text=Why%20does%20the%20thymus%20involutes%3F https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3295077/#:~:tex... I am one of the only transhumanist on earth to know that the thymic hormone thymalin restore thymus function and increase lymphocite T production by 680% and that this effect has been tested to lead to a 410% reduction of all cause mortality in humans. https://pubmed.ncbi.nlm.nih.gov/33237528/ https://pubmed.ncbi.nlm.nih.gov/33237528/ It's non use (e.g it was the trivial day 1 covid cure) is causing millions of deaths daily and induce misery in the quality of life of so many humans. Unfortunately science illiteracy is too strong for mankind to evolve past its infancy. The same could be said about Skq1.
JPLeRouzic 4y ago
As it is not told by the university PR article, I think it's important to state this is about axonal regeneration, not neuron's body regeneration. https://www.science.org/doi/abs/10.1126/science.abd5926 https://www.science.org/doi/abs/10.1126/science.abd5926
Linda703 4y ago
[dead]
Terry_Roll 4y ago
Sodium (Salt) increases the Th17 cells https://en.wikipedia.org/wiki/T_helper_17_cell https://en.wikipedia.org/wiki/T_helper_17_cell and it looks like Th17 also stimulate CD8+ cells. https://pubmed.ncbi.nlm.nih.gov/21660450/ https://pubmed.ncbi.nlm.nih.gov/21660450/ So it looks like junk food & Govt Food regulations mandating sodium preservatives can dumb you down!
born-jre 4y ago
At this point we could probably give best medical care to all the mouse if we wanted. We probably have cure for their cancer and now way to reverse age too. Other day there was article about how injecting brain fluid from young mouse to old one helped its brain or sth. #lilbit_sarcasm :D

141 points by mrtedbear 4y ago

rogerkirkness 4y ago

This feels like one of those - there is probably a reason for that - moments.

TrainedMonkey 4y ago
Possibly. Assuming yes, brings up a question of whether that reason still applies.
kgc 4y ago
Likely reduces incidences of cancer.
- majidmir 4y ago
  Probably on both cellular and social scales
  - neuronic 4y ago
    The T-cells should up their ante then.
oneoff786 4y ago
Biological systems that include death as a feature propagate more effectively
- throwawayboise 4y ago
  Yes, and death also enables reproduction without eventual overpopulation. Reproduction leads to mutation, which evolves the species.
- TedDoesntTalk 4y ago
  So what about the Hydra and turritopsis dohrnii?
  - oneoff786 4y ago
    Local maxima of the fitness function
Aperocky 4y ago
The reason might not be for the health of the individual - as evolution emphasize reproductive fitness and not longevity. Evolution make individuals of a specie healthy and fit until they reproduce and raise their young, and after that the evolutionary pressure becomes negative (are now competing against offspring success in limited resources).
- turtledove 4y ago
  This is notably prevalent in octopus, who are incredible creatures with short lifespans post reproduction.
- cortic 4y ago
  One of the reasons we live so long is that the evolutionary pressure is not negative after reproduction; To begin with it takes 15+ years to raise human offspring to a stage where they might be able to fend for themselves. 20+ years to give them advantage in the environment. Grandparents relieving this burden for each generation greatly increases their reproductive success, far beyond procreation. This is of course similar to other animals, but the benefits are amplified by at least two major factors in humans. First the usefulness of inherited complex knowledge. And second, because of fetal underdevelopment due to birthing hip limitations in evolved bipedal locomotion.
  - throw827474737 4y ago
    Hm not true, a lot of other factors like medicine more relevant, would even say that modern human society has taken out almost all evolutionary pressure except for really bad conditions?!
    - klipt 4y ago
      Not at all, in fact modern society has added many new evolutionary pressures. E.g. by inventing birth control, society gave an evolutionary advantage to people who refuse to use birth control for religious reasons, or people whose biology is incompatible with birth control, e.g. a woman for whom the pill just doesn't work, is likely to have more children.
jostmey 4y ago
Perhaps not! Evolution does not select for longevity once enough time has elapsed for sufficient reproduction
arcticbull 4y ago
I mean, the female hyena gives birth through the clitoris. Not all evolutionary decisions are optimal for the individual. Some are just horrifying and weird.
- Hedepig 4y ago
  This. Another example is the recurrent laryngeal nerve.
  - andai 4y ago
    >The extreme detour of the recurrent laryngeal nerves, about 4.6 metres (15 ft) in the case of giraffes, is cited as evidence of evolution, as opposed to intelligent design. The nerve's route would have been direct in the fish-like ancestors of modern tetrapods, traveling from the brain, past the heart, to the gills (as it does in modern fish). Over the course of evolution, as the neck extended and the heart became lower in the body, the laryngeal nerve was caught on the wrong side of the heart. Natural selection gradually lengthened the nerve by tiny increments to accommodate, resulting in the circuitous route now observed. https://en.wikipedia.org/wiki/Recurrent_laryngeal_nerve#Evidence_of_evolution https://en.wikipedia.org/wiki/Recurrent_laryngeal_nerve#Evid...
- b112 4y ago
  https://www.hyaenidae.org/how-does-the-female-spotted-hyena-give-birth/ https://www.hyaenidae.org/how-does-the-female-spotted-hyena-... I just found this, reading up on your comment, and by god I hate SEO spam, and auto-generated docs.
SemanticStrengh 4y ago
Death is in part an evolutionary advantage. The thymus of humans self atrophy in order to kill the elderly
- formerly_proven 4y ago
  > The thymus of humans self atrophy in order to kill the elderly [citation needed]
  - JPLeRouzic 4y ago
    2009: "There is an accumulating body of evidence that a decline in immune function with age is common to most if not all vertebrates. For instance, age-associated thymic involution seems to occur in all species that possess a thymus, indicating that this process is evolutionary ancient and conserved. ... we show that life history trade-offs play a key role and we highlight the possible advantages of the age-related decline in thymic function." https://www.cell.com/trends/immunology/fulltext/S1471-4906(09)00105-7 https://www.cell.com/trends/immunology/fulltext/S1471-4906(0... 2021: "The thymus begins to degenerate as early as the second year of life and continues through aging in human beings, leading to a decreased output of naïve T cells, the limited TCR diversity and an expansion of monoclonal memory T cells in the periphery organs. These alternations will reduce the adaptive immune response to tumors and emerging infectious diseases, such as COVID-19, also it is easier to suffer from autoimmune diseases in older people. " https://clinicalepigeneticsjournal.biomedcentral.com/articles/10.1186/s13148-021-01197-0 https://clinicalepigeneticsjournal.biomedcentral.com/article...
    - SemanticStrengh 4y ago
      Great links! You might be interested in my answer too
  - SemanticStrengh 4y ago
    > total loss of thymic reticuloepithelial tissue and the associated thymocytes should occur only at the age of 120 years in humans. The thymus involution is the most obvious hard limit for Ageing beyond 120 years old. At age 70 your thymus has 100% shutdown and the only T cell immune system you have left are the old one still remaining in your bloodstream) (the half life is of 17 years) The involution of the thymus (3% per year) has no consensual explanative theory behind it but the two main theories are: 1) a fact is that thymus involution appear by biologically controlled mechanisms, it appear too soon (teenage years) to be mainly due to a normal effect of an accumulation of damage (aging) although reducing oxidative stress reduce the rate of loss of thymus. Another fact is that it is universal among mammals, and since a long time it is a conserved evolutionary mechanism. Now I'd like you to appreciate for a minute how lucky we are and how absurdly kind life is with us. We are optimized for survival in a world with scarce resources. We should have developed atrocious mechanisms that would make the human condition deep shit for increased survival but we have mysteriously not. E.g after taking your meal of the day we should go into low energy consumption mode, have much reduced muscular and cognitive abilities) except in the presence of dangers/stressor, until the next day. As I said, mysteriously we are not too much behavioiraly optimized but that does not preclude that some mechanisms (especially ancient mechanisms) have been designed for hardcore resource contraints and therefore have surprising tradeoffs. The thymus is an energy consuming organ but it's not needed for medium term survival. Because the t cell it has produced will still work for the next 20-30 years. The age of reproduction in humans is well below 40 year old and evolutonarily speaking, a human leaving past its age of reproduction is an absurd inefficiency. It does not contribute much to the survival of the group and it consumes critical resources. It would often be logical to induce an instantaneous death to humans past a certain age (evolutonarily speaking). Many living beings, especially insects, die after reproduction, usually being eaten by the mother/childs. Again nature has been kind with us, but basically thymus involution is like killing you after the age of reproduction, except it's a very slow process that reach completude at 70 years old and absolute immune absence at 120. (note that this is only about T cells, the spleen (producing b cells) is another topic although it doesn't age well either). So yeah this theory it the most potent to explain why the thymus involute. Since this theory is a bit harsh for politics, researchers do not talk much about it. They fallback on a milder version where they simply say that the thymus in itself consume energy and reducing it allow for oleer people to consume less energy (or allocate it to other things) without addressing the obvious evolutonnary advantage of controlling lifespan. Their milder theory is probably true in conjunction with mine. A backing evidence of them is that testosterone reduce the thymus, possibly for resources competition. https://pubmed.ncbi.nlm.nih.gov/9427047/ https://pubmed.ncbi.nlm.nih.gov/9427047/ "Why does the thymus involutes?" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3295077/#:~:text=Why%20does%20the%20thymus%20involutes%3F https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3295077/#:~:tex... I am one of the only transhumanist on earth to know that the thymic hormone thymalin restore thymus function and increase lymphocite T production by 680% and that this effect has been tested to lead to a 410% reduction of all cause mortality in humans. https://pubmed.ncbi.nlm.nih.gov/33237528/ https://pubmed.ncbi.nlm.nih.gov/33237528/ It's non use (e.g it was the trivial day 1 covid cure) is causing millions of deaths daily and induce misery in the quality of life of so many humans. Unfortunately science illiteracy is too strong for mankind to evolve past its infancy. The same could be said about Skq1.

JPLeRouzic 4y ago

As it is not told by the university PR article, I think it's important to state this is about axonal regeneration, not neuron's body regeneration. https://www.science.org/doi/abs/10.1126/science.abd5926 https://www.science.org/doi/abs/10.1126/science.abd5926

Linda703 4y ago

[dead]

Terry_Roll 4y ago

Sodium (Salt) increases the Th17 cells https://en.wikipedia.org/wiki/T_helper_17_cell https://en.wikipedia.org/wiki/T_helper_17_cell and it looks like Th17 also stimulate CD8+ cells. https://pubmed.ncbi.nlm.nih.gov/21660450/ https://pubmed.ncbi.nlm.nih.gov/21660450/ So it looks like junk food & Govt Food regulations mandating sodium preservatives can dumb you down!

born-jre 4y ago

At this point we could probably give best medical care to all the mouse if we wanted. We probably have cure for their cancer and now way to reverse age too. Other day there was article about how injecting brain fluid from young mouse to old one helped its brain or sth. #lilbit_sarcasm :D