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Harvesting Organs through Regenerative Medicine

Does harvesting organs from your clone sound like science-fiction to you? Well it is. The concept of generating spare organs from a living clone was used in Michael Smith’s science-fiction novel “Spares” (1997). However, science-fiction has a tendency to become science reality. Today it’s possible to create new organs from your own cells, without firing up human rights activists. The recent development of bioartificial organs, thanks to the field regenerative medicine, has researchers excited about future applications and seems like a much more promising way to replicate organs than the technique used in “Spares”.

Bioartificial organs are composed of the transplant recipient’s cells and synthetic materials. Complex organs such as hearts have been produced artificially decades ago. These artificial organs are complex machines, sometimes used by patients temporarily as they wait for an organ transplant, but in the end they are only machines. Tissue engineers wanted something more lifelike, organs that could actually be a living, functioning part of the body. Currently, researchers like Dr. Macchiarini are producing organs with cells, blood vessels, and nerves. So far, only a few bioartificial organs have been made and transplanted. These are relatively simple organs, like skin, bladders, and tracheas. In June 2011, Dr. Macchiarini successfully produced and implanted a bioartificial trachea into Mr. Beyene, a patient who was in dire need of a trachea transplant due to a developing tumor (Fountain, 2012). Researchers are growing more optimistic about the possibility of organ donors and organ rejection being a thing of the past.

So what’s the science behind bioartifical organs and tissue engineering? It’s unimaginably complicated, which should come as no surprise, but it can be broken down into some simple steps. Remember, organs are composed of tissues, which are a collection of cells that carry out related functions (Silverthorn, 2013). Scientists have been able to regenerate cells for quite some time; the problem lies in getting these cells to come together and form complex structures, like an organ. Researchers solved this problem by developing a framework from synthetic materials. This framework is called a scaffold and is typically made up of fibrous, porous polymers. The scaffold is first seeded with stem cells, and then it’s placed into an incubator for a few weeks. Stem cells are special cells that have the ability to differentiate. Stem-cell-stimulating drugs can help them become specialized cells. These cells begin to multiply, taking to the shape of the scaffold, which eventually dissolves and is replaced by proteins. You now have an organ that can be stitched onto a patient (Fountain, 2012).

There are some major benefits in using a bioartificial organ over a donated or artificial organ. The obvious benefit is that it can be made in a laboratory. Healthy organs are in short supply. According to an article by National Geographic “More than 100,000 people are waiting for organ transplants in the U.S. alone; every day 18 of them die” (Glausiusz, 2011). On top of the short supply is the likelihood that the patient’s body will reject the donated organ. The immune system is known to attack foreign DNA that enters the body. The patient’s body will not reject the bioartificial organ because it’s made up of his or hers own cells. Another advantage in using a bioartificial organ is that once attached, it’s able to receive blood and the nutrients it needs to grow and function (Glausiusz, 2011). Artificial organs are more readily available than donor organs, but they lack the ability to receive nutrients from the body and cannot sustain themselves.

Mr. Beyene, the patient who received the bioartificial trachea, has now fully recovered and is doing very well according to a New York Times article that was published in 2012. “Now, 15 months after the operation, Mr. Beyene, 39, who is from Eritrea, is tumor-free and breathing normally. He is back in Iceland with his wife and two small children, including a 1-year-old boy whom he had thought he would never get to know” (Fountain, 2012). Mr. Beyene says his quality of life is much better now. The outcome could have been much different if Mr. Beyene decided not to undergo a bioartificial trachea transplant (Fountain, 2012).

The experimental development of bioartificial organs took place long before Mr. Beyene’s trachea transplant. Some may remember a rather bizarre photograph in the late nineties, of what appeared to be a hairless mouse with a human ear growing out of its back. This was accomplished by leading researcher Charles Vacanti and his colleagues in the Department of Anesthesiology, UMass Medical Center, Worcester, MA. The scientific journal outlining the researchers work was published in 1997, and gained quite a bit of attention from the scientific and public community (Kruszelnicki, 2006). The researchers constructed a human’s auricle; crafted from a synthetic scaffold using polyglycolic acid immersed in a 1% solution of polyacetic acid. The scaffold was seeded with chondrocytes (cartilage cells) isolated from a calf and then implanted into 10 athymic mice. Athymic mice were crucial to this experiment because they lacked a thymus gland, meaning they lacked an immune system so foreign cells would not be rejected. After twelve weeks, the formation of new cartilage was apparent and the structure closely resembled a human’s auricle (Vacanti, 1997). This “human ear” was now a living, growing addition to the mouse; sustained by nourishments from newly grown blood vessels.

The photograph of the mouse growing a human auricle sparked outrage amongst an anti-genetics group, which placed an ad in the New York Times with a caption that read, “This is an actual photo of a genetically engineered mouse with a human ear on its back” (Kruszelnicki, 2006). However, the research that was conducted by Charles Vacanti and his colleagues shows us that genetic engineering or an actual human ear were not responsible for this achievement. Dr. Vacanti and his team’s ability to regenerate tissue (cartilage tissue) was a major accomplishment; however, current research in the field of regenerative medicine is far beyond the stage of only regenerating tissue. At Wake Forest for Regenerative Medicine in Winston-Salem, N.C., researchers are working on creating number of simple and complex organs, which are composed of multiple tissues, such as muscle tissue and epithelial tissue.

An article by ABC News published in June 2012 accredits Dr. Atala, the director of the Wake Forest Institute for Regenerative Medicine, for the world’s first successful bioartifical implant into a human being. While training to become an urologist, Dr. Atala came across numerous children who needed bladder transplants and thought to himeself “Why not try to grow these children new bladders from their own cells?” (Noonan, 2012). Dr. Atala used similar techniques developed by Dr. Vacanti to make this a reality. A small amount of cells were obtained from a child’s bladder, and then multiplied and placed on a biodegradable scaffold. It took seven weeks for the cells to take form to the scaffold, resembling a child’s bladder. This procedure was performed on multiple children and began in 1998, but it wasn’t considered a total success until 2006, since the researchers wanted to prove that a bioartificial organ would still be functioning long after the original implant. “They are still walking around with their engineered bladders, and they are happy with them”, says Dr. Atala (Noonan, 2012).

Dr. Atala has made major contributions to the field of regenerative medicine through his research and current successes; however, Dr. Atala and other researchers at Wake Forest Institute for Regenerative Medicine are still trying to make improvements to bioartificial organs. The institution’s homepage states “our laboratories, our scientists are looking for ways to create insulin-producing cells in the laboratory, engineer blood vessels for heart bypass surgery and apply our regenerative medicine technologies to battlefield injuries” (2013).

Currently, researchers at Wake Forest are trying to develop complex organs using a technique called “bioprinting”. Complex organs, such as a heart, require the construction of highly detailed structures at the minute level to function properly. Bioprinting is capable of producing such details with high precision. The technology being implemented is similar to the one used in your ink printers, but the cartridges are filled with cells instead of ink. The advantage of using this highly modified printer is that it can be programmed to print cells in a pre-determined order. This project was founded by a U.S. Department of Defense program, seeking new ways to prevent battlefield deaths that result from burns. The printer’s original intent was to print layers of skin to treat patients with severe burns, but they have been able to produce bone tissue as well as a two-chambered mouse heart. The most astonishing fact about the printed mouse heart is that it actually beats. Once the cells are stimulated by an electric shock from an outside source, the heart begins to beat (Emspak, 2010).

The ability to generate organs is no longer just a concept as portrayed by science-fiction novels or movies. Thanks to the developing field of regenerative medicine, bioartificial organs are now being made and implanted into humans. This medical breakthrough has restored the quality of human lives and has researchers excited about future applications. The rapid development in the field of regenerative medicine, from Dr. Vacanti’s breakthrough in regenerating cartilage on the back of a mouse to Wake Forest Institute of Regenarative Medicine’s beating mouse heart, makes the idea of going to your doctor’s office and asking for a new organ, like a tune up, seem possible in the not too distant future. The extension of human life is inevitable, but one has to ask how long this technology can extend a human’s life and what the repercussions might be.

Reference:

1. Emspak, Jessie. “Tissue.prn: Desktop Printer Technology Used to Lay Down Regenerated Skin Cells to Treat Burns in Mice: Scientific American.” Tissue.prn: Desktop Printer Technology Used to Lay Down Regenerated Skin Cells to Treat Burns in Mice: Scientific American. N.p., June 2010. Web. 11 Apr. 2013.

2. Fountain, Henry. “BODY BUILDERS; A First: Organs Tailor-Made With Body's Own Cells.” The New York Times. The New York Times, 16 Sept. 2012. Web. 10 Apr. 2013.

3. Glausiusz, Josie. “The Big Idea: Organ Regeneration.” National Geographic Magazine. N.p., Mar. 2011. Web. 10 Apr. 2013

4. Kruszelnicki, Karl. “Mouse with Human Ear.” Mouse with Human Ear › Dr Karl's Great Moments In Science (ABC Science). N.p., June 2006. Web. 10 Apr. 2013.

5. Noonan, Jessica. “Lab-Grown 'Custom' Organs May Be Future of Medicine.”ABC News. ABC News Network, 25 June 2012. Web. 11 Apr. 2013.

6. Silverthorn, Dee Unglaub, Bruce R. Johnson, William C. Ober, Claire W. Garrison, and Andrew C. Silverthorn. Human Physiology: An Integrated Approach. Boston: Pearson Education, 2013. Print

7. Smith, Michael Marshall. Spares. New York: Bantam, 1997. Print.

8. Vacanti CA, Cao Y, Vacanti JP, Paige KT, Upton J. 1997. Transplantation of chondrocytes utilizing a polymer-cell construct to produce tissue-engineered cartilage in the shape of a human ear. Plastic and Reconstructive surgery. 2:297-302

9. “Wake Forest Institute for Regenerative Medicine.” (WFIRM). N.p., n.d. Web. 11 Apr. 2013.

chris.txt · Last modified: 2013/04/11 00:49 by 64.189.67.53