Once the brain has healed from the initial implant of the encapsulated stem cells, the stem cells are genetically engineered to produce an enzyme that eats the microcapsule, freeing the neural stem cells. The stem cells can then migrate deep into the surrounding brain tissue where they provide the missing enzyme.
We are particularly interested in targeting the brain because this area of the body is protected by the so-called blood-brain barrier that has been very difficult to penetrate with therapeutic enzymes that are usually injected into the patients bloodstream, Zappe said. Zappe and Sekula are working to develop technologies that will ultimately enable clinicians to harvest neural stem cells from a patient, genetically engineer them from outside the body and then re-implant them and remotely control their actions in non-invasive ways.
By using inducible gene expression, we hope to provide physicians with external control over capsule degradation and the amount of therapeutic enzyme released into the brain by engineered cells as determined by the dose of drugs that are given to the patient in pill form, Zappe said.
Hunter syndrome is a devastating illness affecting more than 500 children in the U.S. alone. Over time, toxic waste products accumulate in the cells of the body, and, although progression of the disease varies, the majority of children die in their teens. If we can reliably provide the missing enzyme iduronate-2-sulfatase to the central nervous system of these children, we may change the course of this disease. Our technology and methodology also will likely have far-reaching implications for hundreds of other diseases of the central nervous system, Sekula said.
|Contact: Chriss Swaney|
Carnegie Mellon University