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Discussion

    Published:December 08, 2009DOI:https://doi.org/10.1016/j.jtcvs.2009.10.007
        Dr Yolonda Colson(Boston, Mass). I have no conflicts.
        You are to be congratulated on doing an amazing job in getting this to actually work, and I think that you have defined a very nice clinical problem that currently does not have a great solution. Having said that, I think there are a lot of obvious questions in terms of longer-term follow-up and analysis. I have several questions.
        You have 4 different groups that fail for different reasons, except group 4, which does well. Were those groups done sequentially, meaning did you do all the animals in group 1, all the animals in group 2, and so, on so that there is a learning curve in terms of infection and how you do it, or were they randomized?
        Dr Go. Yes, it was randomized.
        Dr Colson. Therefore there were some in the different groups done after your success in group 4?
        Dr Go. Exactly.
        Dr Colson. I read the article that you have submitted, and you also talk about there being no evidence of rejection or reaction. What was done to actually know that other than grossly looking at it because you did a lot of biopsies and obtained a lot of blood samples in the article that you did not talk about here. Second, the animals in group 4 were all killed at 60 days, which is a little less than 1 month after group 3. Is 60 days significant? In terms of longer-term follow-up, does that help us clinically?
        Dr Go. To answer the first question, we took blood samples for analysis, as I mentioned in the presentation, to determine, for example, swine leukocyte antigen and other information and the C-reactive protein level. As for the rejection, I just mentioned the swine leukocyte antigen.
        Excuse me, what was the second question?
        Dr Colson. The animals in group 4 were killed at 60 days routinely rather than seeing what their long-term
        Dr Go. To my knowledge, 1 month in the pig is comparable with 6 months in a human subject, which means 60 days in a pig translates to 360 days in a human subject. However, this is just follow-up for the middle term. I would not say this is for the long-term result.
        Dr Colson. Have you seen that in your patient whose case was published in Lancet?
        Dr Go. Yes. Actually, after 3 months of follow-up, she is doing fine.
        Dr Frank C. Detterbeck(New Haven, Conn). You replaced a 6-cm segment of trachea?
        Dr Go. Yes.
        Dr Detterbeck. Tell me about the respiratory endothelium. It seems like that has been the problem with longer-segment tracheal replacement. Unless I missed it, you were seeding with chondrocytes primarily, right?
        Dr Go. Sorry, I did not hear the question.
        Dr Detterbeck. You seeded your bioengineered grafts with chondrocytes.
        Dr Colson. On the outside and epithelium on the inside.
        Dr Detterbeck. Epithelium on the inside. Okay. I missed that part. Thank you.