Science 20 November 2009:
Vol. 326. no. 5956, p. 1049
DOI: 10.1126/science.326.5956.1049-a
Vol. 326. no. 5956, p. 1049
DOI: 10.1126/science.326.5956.1049-a
Basically there are a few centers in the world raising pigs in sterile environments for islet cell harvest. By transplanting the pig islet cells into human autoimmune diabetes patients the hope is that the pig cells will not be susceptible to the autoimmune response to human islet cells. Hopefully, these cells will act as a near-term solution while the bugs are being worked out of a similar human stem cell approach.
Since pig tissue in a human will obviously mount a strong immune response the New Zealand group is "encapsulating the islets in material that will fend off immune attack while allowing insulin out. The Minnesota team is still working on an immunosuppression regimen that will allow the use of "naked islets," says Schuurman, which the scientists think will have better access to nutrients. Further down the road, scientists at the University of Pittsburgh and elsewhere are working on techniques for shuffling pigs' genes or conditioning patients' immune systems to narrow the species gap."
Obviously the biggest hurdles will be working out the regulatory issues related to grafting living pig tissue into humans to permit clinical trials. An interesting and kind of crazy idea.
What do you guys think about this? What are some of pros and cons you can think of with this approach?
That is a slick concept. It sounds like these people will have a future of immunosupression in order to not fight against the transplanted cells. Do you know if there is any data on immunosupression of those who have autoimmune diabetes in an effort to try and restore function of islet cells? If this is possible, it may make sense to just immunosupress these people, rather then introduce a foreign substance and then immunosupress them. But it may be too late to restore adequate function after disease has presented. Maybe those at high risk (family history, other autoimmune diseases in self) could be screened for antibodies and it found, "prophylactically" immunosupressed before DM presents. That may a hard pill to swallow, though.
ReplyDeleteI would also question that many of immunosuppressives are oncogenic, and it would be controversial to use significant amount of immunosuppressives because of DM.
ReplyDeleteGovernment encourage kidney transplant for chronic renal failure. It throws same question. However, the decision was made due to the life-long medical cost. ( It is sad as it’s not because of the patients’ quality of life.) It is calculated with life-long hemodialysis(HD) vs. transplant, which is significantly costly. It is still believed that it would be cheaper to give transplant than life-long HD.
Now, how about DM? It’s going to be cheaper? Who will be eligible to receive the treatment? Going back to the question of developing cancer, it would be an ethical question that what should be done versus the risks also.
Those are some great questions that I thought of when I read the article. It is a wonderful idea that has a lot of complications to deal with. I want to see some data before deciding how practical it is. I wonder if the timing of advances in human stem cell research will determine whether or not this treatment will be attempted.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteThis sounds like a very clever approach to a novel treatment, but I wonder how much time and resources would be spent making the cells different enough to not be recognized by the patient's autoimmune response but similar enough to reduce the risk of rejection. Also, there is the risk of transfer of porcine retroviruses to humans, which could eventually negatively affect the population at large. As always, I think the question is whether the possible benefit is worth the expenditure of resources and future risks.
ReplyDeleteThis idea itself is not novel because different things "pig" like liver and heart have already been tried to be transplanted without success, the difference however is between tissue and cell state. Here one might wonder in terms of host immune response that an organ has complexity which provides it better protection and at the same time makes it vulnerable to failure due to filaure of one component, the cells in this case might have a better chance at survival since even if some of the population gets destoyed it can possibly be still worth it to transplant, or it can be a simple matter of exposed surface area where an organ is better off preventing its core from host immune response while a strong response (acute rejection) can wipe out the whole population of these cells. Another thing is working out an immunosuppression regimen for this cause will be very tricky since major immunosuppressants like calcineurin inhibitors have diabetogenesis and kidney failure as most prominent side effects because of drug toxicity. I have not read the papaer but I believe these guys would reply on other classes of immunosuppressant drugs for the above reason but they may not be as effective as CsA or tacrolimus.
ReplyDelete