Growing New Organs | TED Talk

Dr. Atala mentions at the beginning how many lives have been saved since we began successfully performing transplants. He notes, however, that the list of patients waiting for transplants has doubled while the numbers of donors has remained flat. What is his explanation for this trend?

0:37 We have a major shortage of organs. In the last decade, the number of patients waiting for a transplant has doubled. While, at the same time, the actual number of transplants has remained almost entirely flat. That really has to do with our aging population. We're just getting older. Medicine is doing a better job of keeping us alive. But as we age, our organs tend to fail more.

He makes a point of saying that if they want to regenerate a specific organ, they want cells from that specific organ in a patient. He says "a windpipe cell already knows it wants to be a windpipe cell." Explain what he means by this.

14.09 if possible, we'd rather use the cells from your very specific organ. If you present with a diseased wind pipe we'd like to take cells from your windpipe. If you present with a diseased pancreas we'd like to take cells from that organ. Why? Because we'd rather take those cells which already know that those are the cell types you want. A windpipe cell already knows it's a windpipe cell. We don't need to teach it to become another cell type. So, we prefer organ-specific cells.

What is an advantage to growing organs from that same patient's cells?

14:09 Because they will not reject. We can take cells from you, create the structure, put it right back into you, they will not reject.

You saw the video of the salamander's foot growing back after an injury. Do humans have the ability to regenerate tissue like this? Explain and provide some examples.

2:44 Yes. Humans can regenerate. Our bodies have many organs and every single organ in your body has a cell population that's ready to take over at the time of injury. It happens every day. As you age, as you get older. Your bones regenerate every 10 years. Your skin regenerates every two weeks. So, your body is constantly regenerating.

Dr. Atala mentions how we currently use biomaterial to "bridge the gap". What does he mean by this? What is an example where this is used?

3:43 One of the ways that we do that is actually by using smart biomaterials. How does this work? Well, on the left side here you see a urethra which was injured. This is the channel that connects the bladder to the outside of the body. And you see that it is injured. We basically found out that you can use these smart biomaterials that you can actually use as a bridge. If you build that bridge, and you close off from the outside environment, then you can create that bridge, and cells that regenerate in your body, can then cross that bridge, and take that path.

What are the steps of engineering an organ?

4:58 if a patient comes in to us with a diseased or injured organ, you can take a very small piece of tissue from that organ, less than half the size of a postage stamp, you can then tease that tissue apart, and look at its basic components, the patient's own cells, you take those cells out, grow and expand those cells outside the body in large quantities, and then we then use scaffold materials. To the naked eye they look like a piece of your blouse, or your shirt, but actually these materials are fairly complex and they are designed to degrade once inside the body. It disintegrates a few months later. It's acting only as a cell delivery vehicle. It's bringing the cells into the body. It's allowing the cells to regenerate new tissue, and once the tissue is regenerated the scaffold goes away.

Why did the immune system only recognize and start fighting the tumor after the polio virus was introduced?

All human cancers develop a shield of protective measures that make them invisible to the immune system. By infecting the tumor with the polio virus, the protective shield is removed, allowing the immune system to come in an attack.

What are some disadvantages of organ transplants? Think about what it is like for people on a donor list and what it is like once you receive a donated organ.

Disadvantages: 1. We have a major shortage of organs 2. Every 30 seconds a patient dies from diseases that could be treated with tissue regeneration or replacement. 3. The donated organ could be rejected by the patient's body.

How does the polio virus work to kill cancer cells in a tumor?

The Polio virus seeks out and attaches to a receptor that is found on the surface of cells that make up nearly every kind of tumor. The doctors re-engineered the polio cells by removing a key genetic sequence and adding a harmless bit of cold virus. The re-engineered polio cells doesn't cause paralysis or death as it cannot reproduce in normal calls. But, it can in cancer cells and when it replicates, it releases deadly toxins that poison the cancer cell.