Wednesday, 8 August 2007

Magnetocapsules protect transplanted beta cells

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Experimentally used to treat type 1 diabetes, pancreatic beta cell transplants require immunosupressive drugs and have yielded inconsistent results. Johns Hopkins researchers state part of the challenge is an inability to track the cells after transplantation. Currently, transplanted cells can be attacked by a recipient's immune system, and the cells cannot be seen, blinding researchers in determining why the cells stop making insulin over time.

A team at Hopkins is testing a new technique which encapsulates transplanted cells in magnetic capsules, allowing the cells to be tracked via magnetic resonance imaging (MRI). After mixing alginate (gooey stuff from seaweed) and Feridex, a material containing magnetic iron ore, they surrounded islet clusters of 500 to 1,000 beta cells with this hardened shell called a magnetocapsule. Super tiny, magnetocapsules are 1/128 of an inch wide. Insulin can pass through the shell's tiny openings, while simultaneously shielding an immune system attack by the body. Sort of like an inside out roach motel with a twist -- insulin out, no bad bugs in.

The magnetocapsules have been tested in pigs and diabetic mice, successfully secreting insulin and avoiding rejection by the immune system. Study co-author Dr. Jeff Bulte, professor of radiology and chemical and biomolecular engineering at Hopkins, stated they hope magnetocapsules will solve the problems of tissue-type matching and immunosupressive drugs associated with cell-based therapies for type 1 diabetes. The study will be published online in Nature Medicine. Read more at Medical News Today.

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