MDNews - Greater Boston

CliniCal fEatuRE the future in a dish building uPon nobel PriZe aWard-Winning research, scientists stand on the Verge oF MonuMental breakthroughs in tissue rePlaceMent and PharMaceutical testing. 12 | Greater Boston MD News ■ mdnEwS.COm iN 2007, SHinya yamanaka, M.D., Ph.D., senior investigator at the Gladstone Institute of Cardiovascular Disease, L.K. Whittier Foundation investigator in stem cell biology and professor of anatomy at the University of California, San Francisco, discovered human adult cells could be reprogrammed to mimic embryonic stem cells. Dr. Yamanaka dubbed these "induced pluripotent stem" (iPS) cells, and although extensive research into iPS cells' therapeutic and pharmaceutical use has not advanced past animal studies, researchers have successfully engineered cartilage and bone in mouse and pig models. The primary benefit of iPS cells is researchers can create any kind of tissue from a single cell, according to Farshid Guilak, Ph.D., professor of orthopedic surgery at Duke University Medical Center. Using mice, Dr. Guilak's team successfully engineered cartilage harvested from adipose cells. To encourage the cells to turn into cartilage, Dr. Guilak's team replicated the anatomical environment in which cells typically differentiate in the body by exposing them to transforming growth factor and bone morphogenetic proteins. Using known sequences of growth factors involved in cartilage a nd bone formation, Dr. Guila k 's team found the growth factor — bone morphogenetic protein 4 — responsible for turning on genetic expression for cartilage. Using these methods, Dr. Guilak and his colleagues have produced the best cartilage he's ever seen in a petri dish, which is where immediate clinical applications may be observed. Engineered cartilage likely won't be approved for transplantation for some time, but the patient-specific tissues present in the lab provide immediate opportunity for medical breakthroughs. "One thing we can readily do now is develop a series of stem cells from different patients to make unlimited supplies of cartilage or other tissues matched to

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