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We watched the Guinness Book of World Records and saw that scientists were growing human parts, like ears, on other species, such as rats. We were wondering how this process was possible. We would appreciate any response. Thanks.
Question Date: 1999-10-08
Answer 1:

I was not able to find any information about a mouse with a human ear from the Guinness book of world records! Did you watch a video on this topic? This sounds like an experiment in tissue/cell compatibility between mouse and human immune systems. Can "foreign" tissue (human cells) be grown on the mouse? (i.e., tissue allowed to grow on the mouse and have the mouse nourish the tissue) These scientists must have found a way to trick the mouse into thinking the human ear tissue was similar to its own cells. This is my best guess!
Other people in my lab have seen a picture of what you described, but since I couldn't find it, let's explore some more about organ transplant and "organ sprouting". (There are things happening in the biotechnical industry right now that beat anything you'll see in the Guinness Book of Records!!)

I have sent you 2 websites that you should check out. Try to answer these questions when you read them:

1) Why would it be better to grow an entire organ (such as kidney, bladder or bone marrow) using your own cells as the "starter material", rather than receiving an organ from another person? (hint: think of your immune system...)

2) Why do you need a "scaffolding" (structural base for bladder?) for the new tissue trying to form an organ to grow on? Why did scientists make sure this structure was biodegradable by your body?

3) How do doctors decide who gets the organs? The sickest people? The richest people? The person who is next on a waiting list? Do you think doctors have a hard time deciding who gets the organs? Would this problem be solved if "sprouting organs" became a common event?

Quote from http://www.msnbc.com/news/180102.asp?cp1=1#BODY

"THOUGH ROUTINE transplantation of laboratory-grown organs into humans remains years away, the field is sprouting like never before. The ultimate goal, researchers say, is to take a small piece of a person's own tissue and grow a "patch" or entire organ that is suitable for transplantation back into the patient.
Such an approach would eliminate problems related to rejection, which occurs when tissue or an organ is transplanted from one person to another, experts say. Moreover, the new methods are expected to be associated with less pain and fewer complications, while solving the problem of supply that now limits transplants of all kinds."

The website above also has information on:

* Biodegradable bladders
* Regenerating limbs
* Hearts that keep beating
* Stimulating bone growth

If you drive a car, did you put that "organ donor sticker" on your driver's license? Ask your parents if they did this too. When you read this site, are you surprised how few organs are actually donated from accident victims to needy patients?

How many organs come from accident victims?

Good luck!

Answer 2:

Wow, what a neat question.I bet you're wondering "is that a _real_ human ear on that mouse?" The answer is.....no. You see, one of the problems in medicine is grafting. Grafting essentially means to take something that's been cut off and "stick" it back on. In some cases, people have lost their ears in an accident, and if that ear couldn't be retrieved or if it was badly damaged, then the person had to live without an ear. Now, living without the outside of your ear is not going to kill you, but it would be nice to restore that person's ear to its original appearance, right? Nowadays, scientists can take some of your cells and culture (grow) them in a small dish full of nutrients, but who wants an ear shaped like a small dish? So a few years ago, researchers in Boston perfected a technique to culture these cells on the backs of mice. Now you're probably wondering how they get them to look like ears. What the researchers did is mold the shape of an ear out of a biodegradable plastic (which means that your body's cells can dissolve it), sprinkle human cartilage cells on the mold, and then implant the whole thing on the back of a mouse which had been "engineered" to not reject the foreign tissue. While the ear grows, the mouse looks a little strange but it doesn't hear any better. The really nice thing is that they can then remove the ear without killing the mouse. The scientists hope to one day grow noses and ears in test tubes. Who knows, maybe you'll all get jobs growing ears and noses. Just promise me you won't make any Frankenstein monsters.

Answer 3:

(Reference Scientific American, April 1999.)

Body parts are not grown so far really, but the ability to take an undifferentiated cell (a cell that has not decided what it wants to become) and make it into a "skin" cell (or a specific cell type) is here. This change of a cell's identity can be accomplished because the factors that "cause that" change (proteins that bind to DNA in a cell) have been identified. An "undifferentiated cell" has to come from a very early embryo. Thus, a scientist can take one cell type (an undifferentiated cell from an embryo) and make it into a different cell type by just adding those "factors" (proteins) to the medium (food and water) that the cells are growing in. Yes, scientists have taken it even one step further. They have joined together with engineers that can make a "frame" in which to grow those cells. So, if an ear needs to be made, then they can make a plastic-like substance into the shape of an ear with holes that are big enough for the cells to crawl through and then fill the space. Thus, scientists can grow an "ear". However, this "ear" will only look like an ear, but will not have hair and the finer features.

On the other hand, skin is grown easily in the laboratory, and they use that skin to patch someone that has been injured and had their own skin removed. However, it is skin, but it is fresh new skin (young looking), so if the patient is "old" or "older" then the "new" skin will not look like their "old skin.

Answer 4:

To grow human organs, you need the following. i) human cells, ii) a scaffold (a piece of special plastic) on which cells can grow, and iii) a supply of nutrients (oxygen, glucose etc.). To make human organs, scientists first make plastic scaffolds of the shape of a human ear. They put human cells on it. To obtain the cells, scientists take a small section of the somebody's ear and separate cells from it. The scaffold that is loaded with cells is placed in a special solution, which is full of nutrients (serum). The scaffold is allowed to sit in serum for a few weeks under clean conditions. Scientists then remove the scaffold and attach it to the rat skin. The "human ear" continues to get a supply of nutrients from the rat blood. The cells in the scaffold multiply and develop into a complete ear. Plastic in the scaffold dissolves in a few weeks and we get our ear.

Most human cells are capable of multiplying and communicating with their neighbors in order to develop into a functional mass what we call organ. They need some support (plastic scaffold) and nutrients (serum or rat blood) and they can manage the rest. The field of growing functional organs from human cells is called tissue engineering.

Answer 5:

This is now possible through a technology called tissue engineering. A synthetic scaffold of (usually) collagen is made, supplemented with proteins to which cells know how to stick and remain viable. This scaffold, or matrix, is shaped into the desired for shape(e.g., earlike) then implanted. In the back of a rat these seeded scaffolds grow in the shape of tissues desired to be replaced, e.g., ears).

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