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Growing Organs in the Lab

Tissue Engineering and Regenerative Medicine part 1 -组织工程 & 再生医学 (一)

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Painting hangs at the Countway Library at Harvard Medical School. First time an organ was ever transplanted in 1954. Joe Murray in the front getting the patient ready for the transplant, while in the back room, Hartwell Harrison, the Chief of Urology at Harvard, actually harvesting the kidney. The kidney was the first organ ever to be transplanted to the human.

After 62 years, we’re still facing many of the same challenges as many decades ago. Certainly many advances, many lives saved. But 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.
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In the UK alone around 1,000 people die every year for lack of an organ transplant, and another 10,000 are waiting for one. For many, this is because Britain has an “opt-in” regime of informed consent: 90% of Britons say they approve of organ donation, but only 30% have signed up. Most other European Union countries have some form of presumed consent, in which everyone is assumed to be a donor unless he expressly “opts out”.

TAPb (Tissue Access for Patient benefit) in University College London aim to facilitate the pathway for access, storage, use and transfer of human organs, cells and tissue between clinical centres within UCL Partners, academic groups in UCL, other universities, hospitals, medical researcher and biotechnology companies, to enhance the ability for researchers to access the materials they need. Alongside this, researcher will be able to exchange information and access guides on regulatory, ethics and practical issues concerning access, transfer and use of this type of material. These guides will be video and documents format, based on talks at organised events given by experts in the relevant fields. All of this information will be accessible on a website that seeks to link groups within UCL and attract attention from the wider world through social media and expansion of existing contacts.
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There are three different ways to donate. These are: 1. Brain stem death. 2. Circulatory death 3. living donation – Whilst you are still alive you can choose to donate a kidney, a small section of your liver, discarded bone from a hip or knee replacement and also your amniotic membrane (placenta).

As we know populations are aging the challenge faced is not just for organs but also for tissues. Trying to replace pancreas, trying to replace nerves that can help us with Parkinson’s. These are major issues. This is actually a very stunning statistic. Every 30 seconds a patient dies from diseases that could be treated with tissue regeneration or replacement. There are many approaches such as using new materials, using stem cells, engineering better drug delivery methods etc.
Wouldn’t it be great if our bodies could regenerate? Wouldn’t it be great if we could actually harness the power of our bodies, to actually heal ourselves? It’s not really that foreign of a concept, actually; it happens on the Earth every day. This is actually a picture of a salamander(蝾螈).

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Salamanders have this amazing capacity to regenerate. During limb injury, limb regenerates in a period of weeks.

Salamanders can do it. Why can’t we? Why can’t humans regenerate? Actually, we can regenerate. Your body has 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. The challenge occurs when there is an injury. At the time of injury or disease, the body’s first reaction is to seal itself off from the rest of the body. It basically wants to fight off infection, and seal itself, whether it’s organs inside your body, or your skin, the first reaction is for scar tissue to move in, to seal itself off from the outside

So, how can we harness that power? One of the ways that we do that is actually by using smart biomaterials. How does this work?

Below is an example of synthetic windpipe developed by team in UCL division of surgery and interventional science. Professor Seifalian designed and developed the trachea scaffold using a material known as a novel porous nanocomposite polymer-POSS-PCU (Polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane). A nanocomposite is a material containing some components that are less than 100 nanometres (nm) in size. To give a sense of scale, a human hair is about 60,000 nanometres in thickness. A polymer is a repeating chain of small, identical molecules (called monomers) which are linked together.
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Skeletal formula of POSS-PCU. This novel nanocomposite (纳米合成物) polymer has been used in constructing scaffolds for artificial organs as well as protective coating for medical devices.

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Professor Alex Seifalian and his team designed and built the synthetic(人造) windpipe ‘scaffold’ used in an operation in Sweden announced by the Karolinska University Hospital and Karolinska

Polymers (聚合物) are already used in medical devices, but the properties of these novel polymers reduce the risk of rejection, rupture, or the need for repeat surgery. They have better elasticity, strength and versatility and are formulated to encourage cell growth.

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A full size ‘y-shaped’ trachea scaffold (气管支架) was manufactured in Professor Seifalian’s labs. This was accomplished using a CT (computerised tomography) scan of the patient as a guide, to create the exact shape and dimension needed. A mould was then made using glass. The windpipe after the stem cells (干细胞) have been incorporated, just before transplantation.

作者: Amy_Li

Amy 目前是伦敦大学学院博士,主要的研究方向是硅酸盐生化玻璃,假体离子和骨细胞相互作用



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