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| The Inside Anatomy of the Ear |
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In one study, science researchers approached this problem by looking at stem cells to regenerate the hair cells. We have many different cells in our bodies that come together to form our organs. Many cells already know what they are defined as, such as in this case the hair cells job is for balance and hearing. This can be compared to different majors in colleges. One person may be studying biology to become a doctor and another person may be studying theatre to become an actor or actress. All of these studies are specific but are important for society. This relates to cells who have their own specific jobs that are important for our bodies.
However, we have some cells that are like the undecided majors in college, who are not sure of what they want to do yet. These undecided cells are called stem cells. These cells that we have in our body are not specialized. These cells have the potential to develop into any specialized cells, just like the undecided major has the opportunity to decide to be either a biology major or theatre major etc. In this study, the scientists are coaxing these unsure cells to become hair cells. Some of these stem cells that are located in our body our in our bone marrow. The bone marrow is the spongy tissue inside some of your bones that contain stem cells. The researchers goal in this study was to move the stem cells in the bone marrow to the inner ear to regenerate hair cells. The researchers did this by using G-CSF (Granulocyte Colony Stimulating Factor) which is a factor that will cause the stem cells from the bone marrow to be sent into the blood stream, so that these cells are able to travel from the bone marrow to the inner ear.
This study was done in rats because they have a similar inner ear structure to humans. The researchers used 30 adult male rats in this study. They made sure that all of them had good hearing before experimentation was initiated. These rats were divided into two groups. The first group was called the control group,where these rats were not subjected to the experiment.They were dissected to observe their hair cells so that it can be compared with the hair cells of the rats that will be experimented. This was done to see how successful the use of stem cells are in the regeneration of new hair cells. The second group of rats were the experimental group. The researchers added a toxin so that their hair cells were damaged and the rats were deaf. 5 of these rats were not treated with G-CSF so these deaf rats could be compared to the other rats that were treated with G-CSF. After 5-6 months of treatment, 5 out of 12 rats who had damaged hair cells (who were deaf) that had G-CSF treatment were able to hear again. Therefore, the stem cells became hair cells in almost 50% of the rats and their hearing was restored.
This research is important because it helps lead to the cure of deafness. However, the question is why only half the mice who were treated had restored hearing? Could other factors help restore hearing? There is still more research that needs to be done.
Read About The Research Study Here
The G-CSF (Granulocyte Colony Stimulating Factor) seems like such a specific tool for researchers to use. I wonder how it stimulates the stem cells to move from the bone marrow through the blood stream to the specific target of the inner ear? Could this redirection be utilized for other defected areas of the human body?
ReplyDeleteSounds like an exciting new field of research!
Hi Grace! My first question would be your question! Why only 5/12. It sounds like a possible delivery challenge. Did the authors speculate on the issue? Was this an i.p. injection? Was there histology to see if hair cells were coming back in some rats, but just not functional yet for hearing?
ReplyDeleteFirstly, how do the inner hair cells contribute to maintaining balance? I really liked your analogy comparing stem cells to specific college majors because it made the concept easily understandable. I know that G-CSF (Granulocyte Colony Stimulating Factor) makes the stem cells from the bone marrow travel to the bloodstream, but how do they know to go to the inner ear? Is there a specific receptor in the inner ear? Essentially the stem cells work to regenerate the inner ear hair cells in order to restore hearing. This field of research has a lot of potential because stem cells can be used in a multitude of ways to cure different disorders and diseases because of their regenerative properties. I wonder why this experiment was only 50% successful - was it because some stem cells didn't make it to their target in the inner ear or because they couldn't migrate out of the bloodstream and into the inner ear?
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ReplyDeleteGrace,
ReplyDeleteI felt that our posts complimented one another very nicely. I believe the cochlear implant is, at the moment, the best way to surpass the damaged hair cells. It would be incredible if scientists could figure out a way to more successfully regenerate the hair cells and then transfer that knowledge to humans. Cochlear implants do an amazing job at bringing sound to deaf individuals but the sounds these people hear are no where near perfect. If the hair cells could be completely regenerated, it would put an end to an invasive surgery and some of the challenges of a cochlear implant (example: they are not water proof!). I was also intrigued that these hair cells could throw off someone's balance. But it definitely makes sense! .Like Natalie, I wonder if these techniques could be utilized to regenerate other structures in the body. I am very interested to hear if studies similar to these will be more successful in the future!
It was interesting to see how stem cells may be used, especially after having covered them in class. I liked the analogy that you used, comparing stem cells to undecided majors, it worked well. It's interesting how promising the research in this field is, even 5 out of 12 rats regenerating their hearing is good (Compared with the alternative of none of them). I'm sure that these methods will be honed and perfected in future experiments, as we learn more and more about theses cells and what they can do for us in countless situations.
ReplyDeleteI am also curious why only 5/12 of the rats regained their ability to hear. It make you wonder if there are other gene products or epigenetic changes that are important in the generation of these hair cells. This article has a lot of promising implications for the future of stem cell research in general and to target hearing loss. I would like to see another study performed by this group to test why only the 5/12 could hear, and see what other factors may have a role in this.
ReplyDeleteIt's very interesting how more and more experiments are using mice as model organisms for potential treatments in humans. You mentioned how the mice were tested initially to make sure they have 'good hearing'. I'm just curious to how one can speculate whether or not a mouse has good hearing when their could be external queues influencing what they hear or see. This article shows a lot of progression in terms of potential aides in hearing deficits; however, it would be interesting if there was another study conducted with a larger sample size. Even if less than half the mice had hearing restored, it is still a positive sign in the right direction for further experimentation and research in this field of study.
ReplyDeleteI found this article very interesting and its findings exciting! Working at an Emergency Department, I have realized that many people come in because they are experiencing dizziness or vertigo. It is more common than I realized before working there. I wonder if damaged hair cells are a common contributing factor to this. Further, it would be interesting to see if repair of these hair cells would decrease symptoms in people who have experienced them. While only 5/12 rats regaining hearing may not seem like a lot, it is still early in the research and I'm sure these numbers will improve in further tests. With all the recent advances in stem cell research, hopefully they will be trying this on humans in the near future. It could potentially permanently help so many people with both hearing problems and dizziness!
ReplyDeleteI can't imagine what it must be like to live in a world with no sound. It is exciting to see improvements being made that could potentially reverse the causes of deafness. My grandfather has been deaf in one ear for the majority of his life and now I wonder if it has something to do with damage of his inner ear cells. I think this ties in nicely with what we've learned in class about stem cells and their potential to turn into a variety of new cells. I also wonder how these stem cells get directed from bone marrow to the ear. I hope further research will increase the success rate in rats and then eventually be performed on humans.
ReplyDeleteThis is well written with its comparisons that are easy to grasp for those unfamiliar with science terminology. That being said, it is also an interesting post for those who understand biology, as it always is amazing to see improvement in a field that would assist many. While only 50% regained hearing, this is still remarkable as they were completely deaf before. This may impact people with some damage as they might be able to hear better with a greater success rate. I’m sure with further research a more effective cure will be developed, and the common problem of hearing loss could be cured without the need of devices.
ReplyDeleteI thought the use of the majors to explain stem cells was a very good idea! I wonder why they used such a small sample size because I remember from statistics that you need a sample of at least 40 to even start to make the findings significant and reliable. The G-CSF seems like it could be very useful at treating people with hearing loss. I also wonder why it only worked in 50% of the mice treated. I wonder if maybe when they made the mice deaf they could have accidently caused some nerve damage which made it so that way it only worked in 50% of the mice.
ReplyDeleteI am very interested in this research, especially because hearing loss seems to run in my family and I know I most definitely listen to the radio too loud when I am in the car. I was wondering how old these mice were when they were in the study. The multipotent stem cells from the bone marrow niche knew to enter the blood stream because of G-CSF, but what was the factor that told them to go to the ear? Also, would stem cells from other niches also be able to be tried in an additional study to see if maybe they would lead to more mice experiencing a return of their hearing?
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