Carnegie Mellon researchers to develop new drug delivery systemNovember 05, 2007Researchers use adult neural stem cells to fight Hunter syndrome 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. Zappe, who is working with Dr. Raymond Sekula, a neurosurgeon at Allegheny General Hospital, said he selected adult neural stem cells for his work because they can be harvested from a patient's brain, have the potential to be multiplied outside of the body, can be genetically engineered, can disperse within the brain once re-implanted and can replace all major cell types of 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. "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 patient's 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. Carnegie Mellon University |
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| Related Stem Cells Current Events and Stem Cells News Articles Gene mismatch influences success of bone marrow transplants A commonly inherited gene deletion can increase the likelihood of immune complications following bone marrow transplantation, an international team of researchers reports in the November 22 advance online issue of Nature Genetics. New research shows versatility of amniotic fluid stem cells For the first time, scientists have demonstrated that stem cells found in amniotic fluid meet an important test of potential to become specialized cell types, which suggests they may be useful for treating a wider array of diseases and conditions than scientists originally thought. First reconstitution of an epidermis from human embryonic stem cells Stem cell research is making great strides. This is yet again illustrated by a study carried out by the I-STEM* Institute (I-STEM/ Inserm UEVE U861/AFM), published in the Lancet on 21 November 2009. The I-STEM team, directed by Marc Peschanski has just succeeded in recreating a whole epidermis from human embryonic stem cells. Bone Implant Offers Hope for Skull Deformities A synthetic bone matrix offers hope for babies born with craniosynostosis, a condition that causes the plates in the skull to fuse too soon. Your Own Stem Cells Can Treat Heart Disease The largest national stem cell study for heart disease showed the first evidence that transplanting a potent form of adult stem cells into the heart muscle of subjects with severe angina results in less pain and an improved ability to walk. The transplant subjects also experienced fewer deaths than those who didn't receive stem cells. Is hepatic differentiation of embryonic stem cells induced by valproic acid and cytokines? Embryonic stem (ES) cells, known for their capacity to proliferate indefinitely and differentiate into almost all types of cells including hepatocytes, have raised the hope of cellular replacement therapy for liver failure. Paradoxical protein might prevent cancer One difficulty with fighting cancer cells is that they are similar in many respects to the body's stem cells. By focusing on the differences, researchers at Karolinska Institutet have found a new way of tackling colon cancer. The study is presented in the prestigious journal Cell. U of M researchers find 2 units of umbilical cord blood reduce risk of leukemia recurrence A new study from the Masonic Cancer Center, University of Minnesota shows that patients who have acute leukemia and are transplanted with two units of umbilical cord blood (UCB) have significantly reduced risk of the disease returning. The use of stem cells in regenerative medicine may also be detrimental for health The use of stem cells in regenerative medicine is not always beneficial for human health, it may even be harmful according to a work done by the University of Granada and University of León. Scientists have demonstrated that transplantation of human mononuclear cells isolated from umbilical cord blood exerted a deleterious effect in rats with liver cirrhosis. Penn Study Provides First Clear Idea of How Rare Bone Disease Progresses An international team of scientists, led by researchers at the University of Pennsylvania School of Medicine, is taking the first step in developing a treatment for a rare genetic disorder called fibrodysplasia ossificans progressiva (FOP), in which the body's skeletal muscles and soft connective tissue turns to bone, immobilizing patients over a lifetime with a second skeleton. More Stem Cells Current Events and Stem Cells News Articles |
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