Gene Silencing May Improve Effectiveness of Islet Cell Transplants for Diabetes

Scientists are reporting that a gene therapy technique called gene silencing shows potential for improving the effectiveness and expanded use of transplants of insulin-producing cells to treat insulin-dependent (type 1) diabetes.

In the new study, Drs. Ram Mahato, Guofeng Cheng, and Lin Zhu, from the University of Tennessee Health Science Center (Memphis, USA), pointed out that transplantation of the pancreas' insulin producing cells, called islet cells, has great potential for treating patients with insulin-dependent diabetes. However, the procedure currently is ineffective for most people because of a tendency of the body's immune system to reject transplanted cells. Studies by other investigators indicate that a specific enzyme, caspase-3, plays a major role in carrying-out this destructive process.

To address this problem, the scientists genetically modified islet cells in the laboratory to turn off, or "silence” the gene responsible for producing caspase-3. When the modified cells were transplanted into the kidneys of mice with insulin-dependent diabetes, the blood glucose levels of the mice became normal for up to 32 days, according to the scientists. When the cells were removed, the blood glucose levels of the mice returned to high levels similar to pre-transplantation levels, confirming that the transplanted cells were functional and effective, according to the researchers.

The study is slated to be published the December 1, 2008, issue of the journal Molecular Pharmaceutics.

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