'Micro-Bubbles' Boost Diabetes Gene Therapy Research

They can sneak therapeutic DNA into the pancreas, experts explain

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By Randy Dotinga
HealthDay Reporter

THURSDAY, May 18, 2006 (HealthDay News) -- In what could be an advance in the use of gene therapy against diabetes, researchers say they've smuggled insulin-producing genes into the pancreas of mice by hiding them in a tiny "bubble."

Then, by bursting the bubble with sound waves, the researchers were able to free the insulin genes to infiltrate the pancreas, which normally produces insulin. Once there, the genes went to work protecting the organ against the ravages of diabetes.

The technique is less invasive than other strategies that require direct injections into the pancreas, the U.S. researchers note.

The approach is "very clever," said Dr. Bob Goldstein, chief scientific officer of the Juvenile Diabetes Research Foundation. "Short of sticking a needle directly into your pancreas and delivering a gene, how am I going to deliver something harmlessly, so it doesn't hurt you and it gets to where I want it to go? That's what's special about this," said Goldstein.

Insulin is the crucial missing piece in type 1 diabetes, the inherited form of the disease that occurs when the body turns on its own insulin-producing cells. Without proper levels of insulin, the body is unable to effectively process glucose, so many diabetics with type 1 disease must inject themselves with insulin each day to keep levels steady.

People with type 2 diabetes -- the much more common, obesity-linked form of the disease -- also don't produce enough insulin, or their cells lose sensitivity to the hormone.

About 1 million Americans are estimated to have type 1 diabetes, while another 18 million suffer from type 2 disease.

In the study, U.S. researchers at Baylor University, the University of Texas and Duke University hid insulin-producing human genes in gas-filled "micro-bubbles" that they injected intravenously into the body. The bubbles reached the pancreas and then were blown open by sound waves produced by an ultrasound machine.

The finding appears in this week's issue of the Proceedings of the National Academy of Sciences.

According to the researchers, the technique succeeded in boosting the ability of the mice to tolerate higher glucose levels. They also found no evidence that the pancreas was damaged, said study co-author Dr. Jiahuan Ding, director of the Molecular Genetics Lab at Baylor University Medical Center in Dallas.

Still, the research is in its early stages. "It is still a long way to go to prove safe and efficacious of gene therapy on large animals before human tests," Ding said.

More information

For more on the latest in diabetes research, head to the American Diabetes Association.

SOURCES: Jiahuan Ding, M.D., Ph.D., director, Molecular Genetics Lab, Institute of Metabolic Disease, Baylor University Medical Center, Dallas; Bob Goldstein, M.D. Ph.D., chief scientific officer, Juvenile Diabetes Research Foundation, New York City; May 15-19, 2006, Proceedings of the National Academy of Sciences

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