Injecting a cocktail of proteins directly into the bodies of diabetic mice, researchers have converted normal pancreas cells into insulin-producing cells -- a genetic transformation that could pave the way for treating intractable diseases and injuries using a patient's own supply of healthy tissue.
The Harvard University scientists activated a trio of dormant genes that commanded the cells to transform themselves, much as a person might upload a new operating system onto a computer to change a PC into a Mac.
Within 10 days, the pancreas cells ceased their normal function -- making gut enzymes to digest food -- and instead produced insulin to regulate blood sugar, according to a study published online Wednesday in the journal Nature.
Doug Melton, co-director of the Harvard Stem Cell Institute and the study's senior author, said the same approach could be used to generate motor neurons for patients with amyotrophic lateral sclerosis, to make cardiac muscle cells for heart attack victims or to create other crucial cells that can repair damage wrought by a range of illnesses.
"We were able to flip the cell from one state into another," Melton said, adding that the approach should be useful in treating disorders in "any case where there's a cell type missing and there are neighboring cells that are still healthy."
The method has been tested only in mice and is at least two to five years from being tried in humans, he said. Applying the technique to other diseases will involve a tedious process of searching for the right combinations of dormant genes and the most effective means of turning them on.
Still, Patricia Kilian, who heads regeneration therapy research at the Juvenile Diabetes Research Foundation, said the technique would sidestep some of the complexities inherent in the highly touted but controversial research involving embryonic stem cells.
"You wouldn't be transplanting cells, so you wouldn't be dealing with immune issues," she said, calling the research remarkable and "very unexpected."
The process, which the researchers call direct reprogramming, relies on the fact that all cells contain a complete library of genes in their DNA.
As cells mature, different genes are turned on and off through a still-mysterious process that ultimately leads to the creation of a muscle fiber, neuron, cardiomyocyte or some other type of cell.
When certain types of cells are damaged or destroyed, there is no easy way to replace them.
