As an alternative to transplanting islets into the liver, which has limited success because cells tend to die off there, Dr. Camillo Ricordi and his colleagues at the Diabetes Research Institute in Florida are working on a tiny, implantable device that creates a safe haven for islet production elsewhere in the body. I call it a “reverse IUD” because an IUD is implanted specifically as an intrusion, to interrupt the natural course of cell bonding, whereas this device hopes to achieve the opposite: islet cell generation.
The current procedure for islet cell implantation is injecting islet cells into the liver, because it’s a more robust environment than the pancreas. “You could cut out half the liver and it would regenerate to its normal size within a few weeks,” Dr. Ricordi tells me. “But the FDA is not totally comfortable with the liver as a reception site, since tissues there can’t ever be removed.” It’s a question of what happens to the cell mass as the islets slowly die off, which they tend to do in the liver.
But what if there were a safe and gentle way to place the islets into their natural environment, the pancreas? Or someplace else in the body where they would thrive? Well, that’s what researchers are trying to accomplish with this little 5 mm diameter device, which looks like a tiny cylinder cage. The hope is to create a “bio-artificial organ” in which the insulin-producing cells can survive and function long-term.
In studies, researchers have implanted the device in rats and left it in place for 40 days until tissue and new blood vessels proliferated around and inside it. Then, through a small incision, the plug is removed and islet cells in a saline solution are injected into the space. So far so good. Scientists found no adverse effects up to 180 days after transplantation. Conversely, where the device was removed, the diabetic condition quickly returned.
DRI is hoping to start clinical trials with humans within the next two years, Ricordi says.
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See also my post on Treating Diabetes at the Community Level, at DiabetesMonitor.com today.
Wow!
That’s an approach I had not heard before. Very interesting.
Thanks for the update!
Is the idea that the pores in the cage are large enough for insulin molecules and red blood cells to go in and out, but too small for white blood cells to get in and destroy the islet cells? They look too big for that (and I’m not even positive they’re different sizes, though I seem to recall reading an approach based on that idea).
no, this tech just provides an alternate site for implantation of islets; it allows vascularization of the subcutaneous space and a place for the islets to reside – it does not provide any immunoprotection.
They actually are having clinical trials for a PEG at CHRISTUS Transplant Institute in San Antonio, TX. I think this is exciting, it is just unfortunate that the supply of islets is so small in comparison to the number of diabetics.
http://www.novocell.com/press_release.php?title=PR_June_12_2006.htm
This link will take you to the parent company doing the PEG encapsulated human islet allografts.
They also have a plan for the short supply of islet cells
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