PITTSBURGH — Carnegie Mellon University's Stefan F. Zappe is using adult neural stem cells to develop a new stem cell-based drug delivery therapy that may ultimately help treat a variety of inherited genetic disorders like Hunter syndrome.
Zappe, an assistant professor of biomedical engineering at Carnegie Mellon, and his graduate student Sasha Bakhru, are creating genetically engineered adult neural stem cells for delivery to patients' brains, where they will be programmed to produce an essential missing protein. In Hunter syndrome, for example, patients are lacking the enzyme iduronate-2-sulfatase that helps cells break down certain waste products. One in every 130,000 boys is born with the rare but deadly genetic disorder.
Successful development of this therapy will move us much closer toward being able to do one form of brain rejuvenation: take out the extracellular and intracellular junk that accumulates with age. A neural stem cell therapy that can get rid of wastes that accumulate due to a genetic defect would provide many of the biotechnological pieces needed to create a neural stem cell therapy to get rid of wastes that accumulate due to old age. For example, genetically engineered neural stem cells could clear out beta amyloid plaques which accumulate in the brains of Alzheimer's Disease sufferers.
Keep in mind that they have a lot of problems to solve before they come up with an effective therapy for the disease they are targeting. But the pursuit of treatments for existing neural genetic diseases is sending scientists down roads where they will solve many of the problems which stand in the way of effective rejuvenation therapies.
This team has developed microcapsules to deliver the stem cells into the brain.
To support their therapeutic goals, Zappe and his team have developed cell-instructive microcapsules that contain neural stem cells. These microcapsules efficiently control whether stem cells proliferate (multiply), differentiate into more specialized cell types like neurons and to what extent implanted stem cells will be allowed to migrate to the host tissue.
Zappe will be using these caviar-sized capsules specifically for rapid manipulation of stem cells outside the body and for reliable delivery of stem cells to the brain. The acute inflammatory response that usually occurs from implantation would normally cause implanted neural stem cells to differentiate into mature cell types that are not able to migrate extensively. Encapsulated stem cells will be protected from such premature differentiation.
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.
They have a lot of work cut out for them. It might take them well over 10 years to succeed. But once they and other researchers like them succeed in sending genetically engineered stem cells into various nooks and crannies of the brain the techniques they develop for doing this will be reusable for therapies aimed at rejuvenating aging brains.
|Share |||Randall Parker, 2007 November 03 05:23 PM Brain Stem Cells|