?{REGENERATION}? Is it possible ???!!

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    • #10899
      CXCR4
      Participant

      Hello to everyone on Biology-online who are reading this. I would like to know if there is anyone studying or working on cell regeneration, or regeneration period. I always had thoughts of wolverine as a child for those of you who know about the comic book hero.

      But besides the childhood dreams I believe this work can help the world in a fast process. But there are many reason probably still pending for Government issues which I do understand. Let me know how you feel and what you think, besides this is Biology online. A place for scientist, doctors,teachers, and students.

      Thanks once again Biology/online.

    • #89027
      mith
      Participant

      Lookup finite cell lines.

    • #89029
      jonmoulton
      Participant

      The axolotl has been used as a model organism for the study of regeneration.

      http://en.wikipedia.org/wiki/Axolotl

      Try searching PubMed for axolotl.

      http://www.ncbi.nlm.nih.gov/sites/entre … rm=axolotl

      Or for full papers, PubMed Central (change the search box in the page linked above from PubMed to PMC).

    • #89036
      Jones
      Participant

      Don’t star fish regenerate?
      Or something similar..

    • #89038
      biohazard
      Participant

      Quite a few lower organisms regenerate (if we are talking about whole new limbs and such). And also some vertebrates are capable of that (like salamanders Jonmoulton mentioned). Even some lizards can grow themselves a new tail, although just once. I’m not sure if this is good enough to count as "proper" regeneration, but at least it’s better than what humans can do.

      Naturally also humans are capable of regeneration to some degree. Best examples probably are epithelial tissue and blood cells, but interestingly also liver can regenerate (being the only internal organ able to do so): only a small bit of liver can regenerate into a functional organ, although not quite as large as the original was. Bit like the lizard’s tail! 😉

      Apparently this was already known by the ancient Greeks, who had this story of Prometheus who was chained to a mountain wall and every day an eagle ate his liver, but the liver grew back every night and the eagle came again to eat it the next day. Good source of nutrition for the eagle, but poor Prometheus…

      Despite these modest yet crucial forms of regeneration we humans have, Wolverine’s regeneration capabilities seem quite impossible for humans to achieve. I think we’re miles away from being able to even artificially create anything but a piece of skin or a nerve, and those already take weeks if not months to grow 😛

    • #89039
      mith
      Participant

      We’re pretty successful with skin because it requires very little blood vessels, compare that to a liver or spleen which are packed with vessels. The scaffolding itself is one of the greatest hurdles we face.

    • #89040
      CXCR4
      Participant

      Thanks for the replys so far that everyone has given, I have been working on the study of bone regeneration. I thought to myself about how iron is a strong oxidating element if I am not mistaken. Do you perhaps think increasing iron or enchancing T-cells work be a strong route. I have heard that metal is also a good source of oxidating, just like wolverine’s metal just a fairy tail though. lol?

    • #89052
      jonmoulton
      Participant

      Increasing blood iron can be dangerous. Iron concentration is a factor that limits the ability of bacteria to live in blood. The body sequesters blood iron with high-affinity chelators (hemopexin is an interesting example of blood-iron scavenging: http://en.wikipedia.org/wiki/Hemopexin). High iron concentration in blood can facilitate growth of bacteria there.

    • #89053
      mith
      Participant

      how does iron oxidation relate to cell regeneration?

    • #89057
      Jones
      Participant

      Because hemoglobin is in red blood cells and it releases oxygen for cell use.

    • #89059
      mith
      Participant

      …that’s assuming there’s not enough oxygen that’s causing the lack of regeneration, I highly doubt that’s the case.

    • #89063
      Jones
      Participant

      You highly doubt it, doesn’t mean it’s not possible.

    • #89073
      biohazard
      Participant

      Lack of oxygen isn’t what limits human tissue regeneration. Unless of course if we talk about, say, pressure ulcers or other such conditions where lack of circulation and oxygen supply is the limiting factor. But the fact that we cannot regenerate a new hand or an eye is not because there’d be too little oxygen available.

    • #89077
      mith
      Participant

      One of my profs is researching the use of stem cells and regeneration and she basically said that the mechanism we evolved to heal and create scar tissue is what prevents us from regenerating limbs. Evolutionarily, it’s more important to stop a large bleed than to actually grow one back. Supposedly if we knew what cocktail of cytokines to use, we’d just pour(in a highly sophisticated manner) some on an open wound and the cells would know what to do.

    • #89078
      Jones
      Participant

      Why, exactly, can’t it be the lack of oxygen?
      I’m not getting this or something.
      There’s no reason why just alternatives to the idea.
      And like zero reason why it couldn’t be, just statements made…

    • #89083
      mith
      Participant

      Well, it if was simply a lack of oxygen, then you could put someone in an oxygen tent and they’d grow back all their missing limbs.

    • #89091
      Jones
      Participant

      SO what if since as long as we have dependable historical records people had already messed something up physically or environmentally that made it hard to regenerate limbs?
      Haha, that would be amazing…

    • #91484
      havonasun
      Participant

      Why not sequence the axolotl, the starfish and others, and compare it to our own?
      There is definitely merit in examining oxygen intake. Ologists of some sort measured the oxygen level in a bubble encased in amber and found it to be around 31-38%. I was taught in school that O2 was at 21%. Current measurements show it at 17% One scientist claims that 12% is fatal. Don’t know where I’m going with this. Just thought I’d regurgitate, I guess. Anyway, we are holographic in the sense that every cell contains the entire DNA sequence, so it seems that we are most likely capable of regeneration. It’s quite possible that our environmental history (thousands? millions of years?) prevents it. Or maybe it’s not intended that we do. Population control would be a bitch!

    • #91486
      Jesse2504
      Participant

      Thats a lecture given on regeneration and stem cells in humans, has some useful information.

    • #91487
      MrMistery
      Participant

      Doug Melton is so awesome 🙂

    • #91502
      Jesse2504
      Participant

      Part of the reason those creatures can regenerate is because of the simplicity of their structure, we are much larger and have many different cell types when it comes to regeneration, evolutionarily speaking the humans who have better repair systems should have increased in frequency and we are the result. If we were able to undergo rapid regeneration the trade off might have been our complexity or other characteristics that increase our fitness in the environment.

      I think regeneration is a very helpful thing to many people as it gives us the ability to be complex and to repair damage to that system.

    • #91558
      kolean
      Participant

      Epimorphic regeneration should be available to any organism, simple or complex. It should just be a recapitulation of the developmental genetic program. Now, there can be a hinderance to accessing the develpmental genetic program, but there should be ways around that. Like how to block fibrosis (scar tissue formation) and proceed to epithelial cells disengaging from the basement membrane and sliding over the wound opening. Dedifferentiation of local cells to form the structure, and then transdifferentiation of the cells following the developmental genetic program and renewing the limb/organ. Cell signaling may be the key to unlocking this mystery.

      And then once this mystery is unlocked and mastered, then we can begin the enhancements (for example Wolverine).

    • #91568
      kolean
      Participant

      While researching regeneration (again), I came across regulatory proteins that are found in oncogenes and for the cell cycle. I wonder if cancer is our mutation towards regeneration, except that we haven’t found the right regulatory proteins to make it work viably yet.

    • #91570
      biohazard
      Participant

      I think cancer is more like a blast from the past – cancer cells resemble unicellular organisms in that they do not see "the big picture" but instead just multiply time after time as long as there are nutrients available, even if it meant their own demise as well.

      Regulatory proteins we have have evolved in part to prevent this in order to make us function as a whole, not as individual cells.

      I find it highly unlikely that we are evolving anywehre towards the ability to regenerate any better than we do now – because as it can clearly be seen, the more "advanced" an organism is, the poorer its regenerative capabilities are.

      Like it has already bee sain in this thread, in bigger animals and especially in warm-blooded ones, there is much more acute need to stop bleeding and create scar tissue to block the wound rather than trying to grow back a limb.

      I believe it would be an extremely challenging task to artificially create an environment where humans could regenerate back a limb, with all the issues of genetic regulation and cytokine/hormone environment that is reguired for it to happen properly.

    • #91574
      kolean
      Participant

      The possibility is there. As you say, humans are quote "advanced", though I would use the word more "complex" (or maybe that we just don’t have full comprehension . . . yet), and that means that there are more processes to repress to get back to stem cell/progenitor/dedifferentiated status. But if the dna "blueprints" are still there, we should be able to create an environment (albeit complex) to facilitate regeneration.
      The cytokine and hormone environment has been brought up in the literature to be conducive to fibrosis. I believe that it is cytokines, though a different cytokine environment than what is expressed now, may be beneficial towards regeneration. True, we may have to repress the immune system thru out the regeneration process though.
      Now the hormone may be the key. Why else would innervation be a requirement for regeneration? A hormone that starts the differentiation development again. And has to start the regeneration process with gradients of factors right at the beginning. With all that massive destruction of cells (amputation), there has to be a release of a threshold gradient of some factor, or possibly factors. This release should trigger the release of this hormone in the nerve axon? A type of neurotransmitter? That is released upon the threshold gradient of massive destruction. Cytokines of course would be involved as they react to the destruction also. But which ones?

      The word cancer is used to describe a general heading of cells gone wild. Somehow they can not carry on their specific function, and may find alternative ways of producing new functions. This can have evolutionary implications. Now some are not viable to the organism, and sometimes they are viable. Procreation of these new functions will produce evolution. Survival of the fitness (though with modern medicine, any viable functioning organism seems to procreate 😉 ) is the theme. Regeneration may be one of those functions. . . . one day (which yes could mean a thousand years or so in the eyes of evolution).

    • #91576
      biohazard
      Participant

      I think I got your point, and yes, "complex" is a good word to describe the same I tried with "advanced". Anyways, I’m not too sure there’s much evolutionary pressure towards regeneration in humans, quite the contrary: we can probably make excellent artificial limbs long before evolution has time to do anything about it 🙂

      This is not to say it is impossible to make humans regenerate a limb, but I fear it’s next to it. I think it’s easier and more realistic to design artificial limbs and organs, maybe even partly/fully biological ones. But you never know, maybe after a few centuries you get to tell me "I told you so!" 😛

    • #91594
      kolean
      Participant

      The more we tinker around with stem cells, the closer we will get to unlocking the mysteries. I am not a big fan of letting Mother Nature do all the tinkering around: evolutionary pressure. Though she gets to make the big evolutionary ones because she can do what she wants and has no rules to follow. Humans on the other hand . . . .

    • #91616
      MrMistery
      Participant

      kolean, i would like you to be right, but i fear that the more we look at in vivo dedifferentiation followed by differentiation into another cell type we see that it might not be a viable treatment option. right now it seems to me that transdifferentiation might be a more viable approach to explore..

    • #91627
      kolean
      Participant

      Can you clarify the distinction between "transdifferentiation" and the "dedifferentiation and then differentiation" that occurs during epimorphic regeneration? Is it just the process of reployment of developmental programming during the latter, while the former has a different process of reprogramming? Because basically, are they not both repressing the phenotypic expression of one cell and transforming it into the phenotypic expression of another cell?

    • #91641
      MrMistery
      Participant

      with transdifferentiation, you are not passing through the stem cell state, you’re just turning one cell type into another more or less directly. this is good because it by-passes the tricky stem cell state. here’s a nice straightforward paper where this approach is used:
      http://www.nature.com/nature/journal/v4 … 07314.html

    • #91667
      kolean
      Participant

      I don’t have full access to the article right now, so what does it mean by:
      . . . using a strategy of re-expressing key developmental regulators in vivo, we identify a specific combination of three transcription factors (Ngn3 (also known as Neurog3) Pdx1 and Mafa) that reprograms differentiated pancreatic exocrine cells in adult mice into cells that closely resemble beta-cells.

    • #91687
      MrMistery
      Participant

      well it’s like iPS cells: they very very closely resemble embryonic stem cells, but they’re not exactly identical. Just like that, those cells don’t have all the same characteristics of beta cells (if i remember correctly they don’t cluster into islands).

    • #93500
      WANNABEBIOLOGIST
      Participant

      ok dont take this as scietific fact as it is just a theory of mine but i believe it is very possable as we are able to regenerate cells as babies and as we are just a fetus but we loose the ability to coordinate our cells. it is the ability to coordinate there cells and cell memory that allows some creatures to regenerate and i believe that our liver is the key to unlocking man kinds full potential. your quetion should be is it possable to use stem cells to engineer a human liver but during its growth process to introduce hormones from a salamander or axolotl to mutate the DNA enough to create human cell with the ability of cell memory and coordination or if it is possable to locate the exact pair genes that give salamanders and axolotl’s the abilty to do this already and introduce that to human but i honestly dont really know what im talking about but someone proove my theory is absolutely impossable and i’ll shake ya hand. 😈

    • #93514
      MrMistery
      Participant

      why do you think the liver is the most important organ?

    • #93519
      kolean
      Participant

      Probably because a human liver can regenerate itself (unless less than 25% of its mass).

      You are thinking like an organ system biologist when you think that the liver can show us how to regenerate. Now with the liver, it just regenerates the same cell over and over (hepatocytes) with the blood vessels and other vessels (epithelium/endothelial) spreading thru it, to produce the tissue mass.

      Now regeneration in a salamander can be plain like the lens regeneration, or it could be as complex as the whole tail or arm/leg. I do not think hormones mutate genes/DNA to create cellular memory. Plus you can not mutate or mess with the DNA genome as that is your original blueprint.

      I think that they just re-express developmental genes (basic original blueprint that has been repressed after the embryological process was completed) using blastemal cells (pluripotent or totipotent seems to be the question lately – but albeit a type of stem cell).

      Blastemal cells are regular cells that de-differentiated from the wound site (though not all the way back to beginning stem cells, as a new article remarks on cellular memory for muscle and nerve cells mostly) and grow to the right size of mass needed for the regenerating appendage. Then they begin to differentiate back to their programmed cell fate.

      Personally, I think that miRNA and PcG/chromatin remodeling will be what we find that lets us dedifferentiate the cell’s programmed fate, and then redifferentiate it with the appropriate environment (here is where the hormones, cytokines, transcription factors, etc. come into play).

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