
In a day and age where super hero blockbusters are all the rage wouldn’t it be incredible if humans had some of those abilities? Super heroes are all the rage in the movie industry and have been capable of taking some of the most obscure powers and render them with near perfect CGI. Sadly super hero’s aren’t real and humans aren’t born with super human strength, the ability to fly, or shoot lasers out of our eyes. However, there is one power in particular that could be replicated if given the necessary tools, that power is a healing factor. Healing factors allows super heroes to take extraordinary amounts of damage that would leave ordinary people in shambles, but with their healing factor they are able to slowly recover. Heroes like Deadpool, Wolverine, and the Flash have the ability to heal faster than normal humans, Wolverine and Deadpool are even able to regrow their own limbs at certain times. But is it possible for a human to regrow limbs? Of course not, not without some help. The field of genetics can lead to a road of infinite possibilities. However, genetics aren’t the only means that could give a human more regenerative power, stem cells are another way that humans can regenerate naturally. Even with the combination of stem cells and isolating genetics this cannot give humans the ability to regrow limbs.  This process can be done by gene splicing human genetics with that of a species that can regrow limbs. Certain types of reptiles are able to regrow their tails or limbs with their cells. Using genetic splicing scientists have been able to isolate genes to further human evolution (SIAM). What does the future of splicing genes with reptiles look like?

Splicing our genes with that of reptiles is a very difficult and dangerous task. If done incorrectly it could possibly kill people and cause some serious side effects. Using another species genetic code and trying to modify it to be compatible with humans sounds like something straight out of a comic book or science fiction novel, but in reality might actually be possible. Genetic splicing is a complicated process that involves scientists carefully extracting enzymes of DNA, and using that enzyme to help further our DNA. The best way to picture it would be like interchangeable puzzle pieces. For example if you had a 3 pieces that were blue and three that were red, and all three are the same shape and corresponded with each other you could swap a piece of the red in for the blue piece and vise versa. This is true for genetic splicing DNA except when the new genetic material is added it becomes a whole new strand of DNA (SIAM Journal on Computing). So genetic splicing is basically taking proteins in the DNA isolating them, and mixing them with desired proteins to create the new strand of DNA. Theoretically this process of genetic splicing could be used when combined with reptile genes to make a new strand compatible with human’s, in order to do this scientists could use stem cells. 

Stem cells have regenerative abilities to become any cell in the body, this can allow the body to utilize them to repair damaged tissues. Scientists have been trying to study the capabilities of stem cells for a while now, and have been using rats as their base of testing. A study in which rats were injected with stem cells show the progress that stem cell regeneration has on the mice. “This study was designed to isolate MSCs from rat BM, and investigate the differentiation potential of these cells into nerve-like cells after treatment with specific growth factors.” (In Vitro Differentiation of Mesenchymal Stem Cells Derived from Rat Bone Marrow into Nerve –Like Cells, Qianxu Lu ).  This study determined that the stem cells in rats regenerated bone marrow tissues and even helped repair the nervous system. 

“Mesenchymal stem cells were isolated according to their adherence to tissue culture flask which gives some degree of purification as non-adherent haematopoietic cells are removed and discarded through the continuous medium changing. After 2-3 days of cultivation, there were groups of rounded cells distributed in the culture as aggregations. In addition, other cells attached as single rounded cells. Then within time of culture, the attached cells became elongated with small uni-polar and bipolar processes or fibroblast like-spindle shape (Fig. 1A). As a result of continuous medium changing, it became clear to distinguish adherent cells with proliferation activity.” 

(In Vitro Differentiation of Mesenchymal Stem Cells Derived from Rat Bone Marrow into Nerve –Like Cells, Qianxu Lu).  This study showed that the new cells that were created using stem cells actually helped the rats regrow some of their nervous tissue. 

  The regenerative capabilities are amazing and have been used in many medical studies to try and treat diseases that attack cells and make them useless or just completely destroy them like cancer. Stem cells are the only cells in the human body that scientists know of that can become any cell and that is why they are so effective in treating diseases and manufacturing them into drugs. Many people have seen the use of making them a super drug such as Susan Solomon she had this to say in her ted talk about stem cells “So, embryonic stem cells are really incredible cells. They are our body's own repair kits, and they're pluripotent, which means they can morph into all of the cells in our bodies. Soon, we actually will be able to use stem cells to replace cells that are damaged or diseased.” (“The Promise of Research with Stem Cells”, Susan Solomon). Her Ted Talk provided information on how stem cells work and their regenerative capabilities. Her most notable statement was 

“So let me put that in perspective for you and give you some context. This is an extremely new field. In 1998, human embryonic stem cells were first identified, and just nine years later, a group of scientists in Japan were able to take skin cells and reprogram them with very powerful viruses to create a kind of pluripotent stem cell called an induced pluripotent stem cell, or what we refer to as an IPS cell. This was really an extraordinary advance, because although these cells are not human embryonic stem cells, which still remain the gold standard, they are terrific to use for modeling disease and potentially for drug discovery”(“The Promise of Research with Stem Cells”, Susan Solomon).  

This ted talk showed the regenerative capabilities of stem cells and how they can be used to treat diseases.  

There is no denying that stem cells work and are an incredible resource to humans. Another article had this to say on the regenerative capabilities of stem cells “In a 1956 review entitled “Renewal of Cell Populations,” Leblond and Walker noted that multiple adult tissues, including the skin and intestines, accommodate numerous mitotic divisions but seemingly do not undergo a commensurate expansion in tissue size (1). The authors presciently concluded that “the cells of the tissue are said to undergo renewal” (1). Such tissues are perpetually being “recycled,” with cells being extruded or lost and continually being replaced by newly born cells.” (Hans Clevers).  Hans makes his stance on the regenerative powers of stem cells and shows that they are able to regrow damaged tissues. This allows for damaged tissues to be healed. For example, if someone had serious damage in the liver from either a rare disease, car accident or drinking excessively. Stem cells would be a possible way to replace and regrow the tissue that was damaged.  The only problem is getting them to regenerate entire limbs, where stem cells can be used to grow back tissues and even some external organs such as ears or other small appendages their regenerative abilities is still much to be desired. Scientists have grown human ears on other animals but there has yet to be results when it comes to repairing a human arm or leg. Even repairing matter in the brain or curing spinal injuries are still way too advanced for the current level of stem cell research. However genetic splicing human stem cells and cells from a reptile with incredible regenerative feats could yield new results. 

To determine what genes humans need we must first take a look at how we ourselves repair our wounds. Humans have an incredible regenerative process in which we use scar tissue to heal deep wounds to prevent blood loss (Peter Martin). However, we cannot make an arm or a leg regrow using scar tissue or any cells in our body Peter describes how regeneration works for humans “Most skin lesions are healed rapidly and efficiently within a week or two. However, the end product is neither aesthetically nor functionally perfect.”(Peter Martin). He reconfirms what was mentioned above, even though we can heal from a loss of a limb it will not be functionally same. “Epidermal appendages that have been lost at the site of damage do not regenerate, and when the wound has healed there remains a connective tissue scar where the collagen matrix has been poorly reconstituted, in dense parallel bundles, unlike the mechanically efficient basket-weave meshwork of collagen in unwounded dermis.”(Peter martin). Essentially when a leg or arm is lost it results in scar tissue forming in the area that was cut. That is the problem with the human regenerative process we are not able to be functionally “The Same” after a traumatic injury. Peter then identifies “A major goal of wound-healing biology is to figure out how skin can be induced to reconstruct the damaged parts more perfectly. Clues as to how this might be achieved come from studies of wound healing in embryos, where repair is fast and efficient and results in essentially perfect regeneration of any lost tissue.”(Peter Martin). Peter is talking about stem cells but in theory it might be impossible to regrow perfect limbs with just stem cells. However using those stem cells with that of an animal that can regrow limbs might be possible to yield better results. The animal in question is a reptile. Reptiles have certain genetic capabilities that allow them to regrow limbs.

 A reptile with the regenerative feats necessary is now the final piece of this equation. Reptiles have incredible regenerative capabilities especially salamanders, they are able to regrow parts of their tail while it is cut off. However, when it comes time to regrow other limbs a simple salamander falls short. In order for a human to be able to regrow limbs the reptile in question would have to be able to regrow any limb or part of its body. Scientists have found a reptile like this its name is the axolotl. This unique reptile is able to regrow any part of its body without fail any number of times (Dynamic membrane depolarization is an early regulator of ependymoglial cell response to spinal cord injury in axolotl). For example a study was done on an axolotl with spinal injuries “To address this question we developed a spinal cord injury model in axolotls and used in vivo imaging of labeled ependymoglial cells to characterize the response of these cells to injury.” ( Dynamic membrane depolarization is an early regulator of ependymoglial cell response to spinal cord injury in axolotl.). So essentially what scientists did was create a spinal chord injury to see how the axolotl’s body would respond. In the study scientists observed just how well the axolotl healed and the process that took place. In a short summary this is what happened, through the use of specific genes and enzymes that the axolotl possesses it was able to regrow its spinal chord perfectly. Perfectly meaning there was no tissue scaring, nerve damage or malformation that occurred. This is the trait that humans should have, this specific trait can offer up a whole new field of scientific discoveries. 

 This feat on its own is fascinating but the really interesting part is that it was able to regrow its limbs without any nerve damage. Nerve damage is also a key factor in re-growing limbs, re-growing the limbs is a challenge in its self, but imagine that it regrew perfectly only to realize the nerves are so damaged there is no feeling in it or it could be shaking out of control. The axolotl’s genes allow the nerves and tissue to regrow perfectly and without scar tissue. The axolotl is even able to regrow organs and parts of its brain. “Unlike starfish or fictional superheroes, most vertebrates cannot regrow their limbs. Axolotls are an exception”( Cell Rep. 18, 762 (2017).). This means that with the right technology and testing we can have super human regeneration using the axolotls traits. 

The technology is all here we have genetic splicing, a super power cell and a reptile that can regrow limbs. When looking at it from a scientific standpoint theoretically it might be possible to cross our genes and that of reptiles to allow greater regenerative capabilities. The only problem is the actual process, like stated before the risks of cross species genetics is unpredictable. Using stem cells is a great way to keep our DNA consistent with our own body but scientists have not yet tested this. Although they offer a way to essentially have a human like cell with reptile capabilities it has not been tested, and results have not been published stating that it works. In theory this sounds great being able to utilize another species traits and apply it to our own body. But the risks can also be grave, when the body has foreign cells the white blood cells often attack and attempt to destroy them. Which is why stem cells can be used to keep the body’s own cellular make up in line. But the genes from the reptiles might cause our own cells to mutate and become foreign leading to high fever and possibly death it is essentially what happens when people get a skin transplant or organ transplant, the body recognizes it as different and decides to kill it resulting in more problems. The payoff however is worth the risk if successful limb regeneration can be possible. Wounded soldiers who have lost limbs in the line of duty might finally have a chance to walk again with their own flesh and blood. An even greater effect would be those who have had brain damage they can regrow and repair their brain enabling them to be healed. Cancer and other diseases would also be rendered useless since the cells would be constantly regenerating. And although cancer and other diseases strive off of them multiplying, the stem cells and axolotl genes would keep the mutations in check.  In conclusion if able the genetic splicing of our cells with that of the axolotls would be a huge breakthrough in the scientific community and would offer a way for humans to recover without the use of scar tissue.  