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      CommentAuthorLBA
    • CommentTimeJan 13th 2008
     (500.1)
    Scientists create a beating heart in lab

    "niversity of Minnesota researchers have created a beating heart in the laboratory.

    By using a process called whole organ decellularization, scientists from the University of Minnesota Center for Cardiovascular Repair grew functioning heart tissue by taking dead rat and pig hearts and reseeding them with a mixture of live cells. The research will be published online in the January 13 issue of Nature Medicine.

    “The idea would be to develop transplantable blood vessels or whole organs that are made from your own cells,” said Doris Taylor, Ph.D., director of the Center for Cardiovascular Repair, Medtronic Bakken professor of medicine and physiology, and principal investigator of the research."
  1.  (500.2)
    It's an interesting way of getting the structure of the heart already in place. What would be a good clinical step would be to see if the decellularized part of the heart would trigger an immune response.

    Tie it in with getting stem cells from adults and we could be on our way to not needing life-long immune suppression therapy.

    Now, time to hit someone with an ATHENS account to read the whole paper and see if the promise is as good as this reporting.
    • CommentAuthorKosmopolit
    • CommentTimeJan 14th 2008
     (500.3)
    Using a real organ as a template is a very interesting idea and gets around the problems of creating complex 3D structure from scratch - so far the most complex thing that's been grown that way is a bladder.

    But it implies you're going to need a donor heart for every new heart you grow. Now I can see that getting away from the need to use immunosuppresant drugs will be a big step forward and I'm sure that some hearts not currently usable will now be able to be used. (I wonder if you can freeze and store the "matrices"?)

    But it still seems there are going to be problems getting enough hearts.

    Seeing as all the actual cells from the original heart are supposed to be removed, I wonder if it would be possible to use animal hearts to create the matrices? That'd really solve the supply problem.

    I'm also wondering whether this approach will work on other organs.
    • CommentAuthorZeebo
    • CommentTimeJan 15th 2008
     (500.4)
    Have read the abstract, will get the rest of the article tomorrow at work and look at it. There may be a short summary posted, depending upon tomorrow's workload.

    There would still be an immunological response to the extracellular matrix elements in the heart.

    Without any developmental signaling components, I'm skeptical that this technique could ever form a physiologically functional heart since it's unlikely that any random cell lineage can form the sinoatrial and atrioventricular nodes, so that will acquire additional work. Also, their current model only has 2% of the force of an adult heart.

    Still, it's a major accomplishment and pretty damn cool all-in-all.
    • CommentAuthorZeebo
    • CommentTimeJan 16th 2008
     (500.5)
    I downloaded and read the article today. It's actually quite convincing and rather cool. The decellularized hearts show a complete lack of nuclei and contractile elements but the collagens and such are still present. All the valves and small blood vessel linings also are still intact and functional. The cardiac cells spread from the point of injection to the surrounding scaffold and beat within 4 days. Within 8 days, they can be paced by electrodes, but have the aforementioned lack of force. The paper reports that they've done the same decellularization procedure with similar results in a pig's heart (which is analogous to a human heart). They also claim to have done it with several other organs including bladder and liver, but give no data to support it.

    Another interesting feature of the biomatrix is that it is firmer than standard artificial biomatrices, which means it's basically much more durable. That's a necessity when making things like a heart that contracts constantly.
    • CommentAuthorKosmopolit
    • CommentTimeJan 17th 2008
     (500.6)
    The lack of force is obviously disappointing but restoring even minimal kidney capacity, for example, could make a huge difference for a lot of people.
    • CommentAuthorHarvey
    • CommentTimeJan 17th 2008
     (500.7)
    There's a couple of useful practical advances to this here ;

    1. Your heart muscle dies pretty easily , making lots of donor hearts useless - using an existing heart as a template for growth of stem cells is a big help
    2. Organs are highly organised - growing them up in the lab from cells has always been hampered by the problems associated with getting your cells to know how to organise thenselves properly. If you can get them grow on a template in the right shape, then you're on a winner.