Efficient insulin gene delivery by ultrasonic microbubble technology

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Researchers have successfully delivered insulin-producing genes to rat pancreatic cells using a technique called ultrasonic microbubble destruction technology (UTMD).

"UTMD allows relatively noninvasive delivery of genes to pancreatic islets with an efficiency sufficient to modulate beta cell function in adult animals," Dr. Paul A. Grayburn from Baylor University Medical Center in Texas and colleagues report in the May 15th issue of PNAS Early Edition.

Briefly, the team incorporated the rat insulin 1 promotor (RIP) gene into tiny gas-filled bubbles and injected them intravenously into the rat. When the bubbles reach the microvasculature of the pancreas, a focused ultrasound beam is used to burst them, freeing their insulin-producing cargo.

According to the team, gene expression in the pancreas was confined to beta cells and was regulated appropriately by glucose.

Moreover, beta cell-specific delivery of the human insulin gene to rats by UTMD led to expression of human insulin and C-peptide, increased glucose tolerance and a lowering of blood glucose.

"Our data," the investigators conclude, "show that UTMD delivers transgenes to islet beta cells of adult living animals at a level sufficient to alter beta cell function, thereby providing a potential means of targeting therapeutic agents to the islets in the setting of diabetes."