Study Finds Blood Cells Can Be Reprogrammed to Act as Embryonic Stem CellsApril 21, 2009In a recent study, U.S. researchers have reprogrammed cells found in circulating blood into cells that are molecularly and functionally indistinguishable from embryonic stem cells, a revolutionary achievement that provides a readily accessible source of stem cells and an alternative to harvesting embryonic stem cells. The findings were prepublished online in Blood, the official journal of the American Society of Hematology. Embryonic stem cells have long been coveted for their potential to treat a multitude of diseases as a result of their unique properties of nearly indefinite self-renewal and pluripotency (the ability to develop into any type of cell in the body), but their use has been the subject of political controversy. "Our findings provide the first proof that cells from human blood can morph into stem cells," said senior study author George Q. Daley, MD, PhD, an investigator for the Howard Hughes Medical Institute at Children's Hospital, Boston. "Making pluripotent stem cells from blood, which is one of the easiest tissues to obtain, provides an easy strategy for generating patient-specific stem cells that are valuable research tools and may one day be used to treat a number of diseases." To generate induced pluripotent stem cells (dubbed iPS cells), blood was collected from a 26-year-old male donor. From the blood sample, the researchers isolated CD34+ cells, a type of stem cell that produces only blood cells, and cultured them in growth factors for six days to increase their number. During the culture, the scientists infected the CD34+ cells with viruses carrying reprogramming factors, genes normally expressed in embryonic stem cells that can reset the blood cells to an embryonic state. Colonies of cells exhibiting physical characteristics similar to embryonic stem (ES) cells appeared about two weeks after the procedure. To determine whether these cells were also functionally similar to ES cells, the scientists analyzed the CD34+ iPS cell lines to see if they had acquired stem cell "markers," the unique combination of proteins that coat the cells' surface and distinguish them from other types of cells. Indeed, the iPS cell lines expressed the same markers as ES cells and further shared the capacity to differentiate into a variety of specialized cell types. In vitro, the iPS cells readily developed into clusters of cells called embryoid bodies from which cells of virtually any type can develop. These differentiated cells expressed genes for all three embryonic germ layers (the tissues from which all other tissue types in the body develop) and also produced myeloid and granulocyte colonies (types of white blood cells). The group confirmed that the reprogrammed cells had acquired ES cell characteristics by injecting the newly reprogrammed cells into immunodeficient mice. The cells successfully generated well-differentiated teratomas, benign masses containing all three embryonic germ layers, including respiratory, bone, and neural tissue. "Not only has this work identified a new programmable cell type, but the cells are easy to obtain and analyze in many research laboratories and bone marrow transplantation centers around the world," said Grover C. Bagby, MD, Professor of Medicine and Molecular and Medical Genetics at Oregon Health and Science University, who is not affiliated with the study. "These findings will immediately enhance the pace of laboratory research in this field and will ultimately help to determine whether iPS cells have a therapeutic potential equivalent to that of embryonic stem cells." To receive a copy of the study, or to arrange an interview with the lead author, reporters may contact Patrick Irelan, ASH Communications Assistant, at 202-776-0544 or pirelan@hematology.org. The American Society of Hematology (www.hematology.org) is the world's largest professional society concerned with the causes and treatment of blood disorders. Its mission is to further the understanding, diagnosis, treatment, and prevention of disorders affecting blood, bone marrow, and the immunologic, hemostatic, and vascular systems, by promoting research, clinical care, education, training, and advocacy in hematology. In September 2008, ASH launched Blood: The Vital Connection (www.bloodthevitalconnection.org), a credible online resource addressing bleeding and clotting disorders, anemia, and cancer. It provides hematologist-approved information about these common blood conditions including risk factors, preventive measures, and treatment options. Blood, the official journal of ASH, is the most cited peer-reviewed publication in the field. Blood is issued to Society members and other subscribers weekly and is available in print and online at www.bloodjournal.org. American Society of Hematology |
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| Related Embryonic Stem Cell Current Events and Embryonic Stem Cell News Articles Of mice and men: Stem cells and ethical uncertainties The recent creation of live mice from induced pluripotent stem cells (iPSCs) not only represents a remarkable scientific achievement, but also raises important issues, according to bioethicists at The Johns Hopkins University's Berman Institute of Bioethics. Endocrine Society calls for expanded scope and funding for stem cell research Stem cell research holds great promise for the treatment of millions of Americans with debilitating and possibly fatal diseases. Small mechanical forces have big impact on embryonic stem cells Applying a small mechanical force to embryonic stem cells could be a new way of coaxing them into a specific direction of differentiation, researchers at the University of Illinois report. Applications for force-directed cell differentiation include therapeutic cloning and regenerative medicine. Stem cell success points to way to regenerate parathyroid glands An early laboratory success is taking University of Michigan researchers a step closer to parathyroid gland transplants that could one day prevent a currently untreatable form of bone loss associated with thyroid surgery. NIH researchers identify key factor that stimulates brain cancer cells to spread Researchers funded by the National Institutes of Health have found that the activity of a protein in brain cells helps stimulate the spread of an aggressive brain cancer called glioblastoma multiforme (GBM). Stem cell research: From molecular physiology to therapeutic applications Stem cell research promises remedies to many devastating diseases that are currently incurable, ranging from diabetes and Parkinson's disease to paralysis. Research may hold key to maintaining embryonic stem cells in lab In a new study that could transform embryonic stem cell (ES cell) research, scientists at UT Southwestern Medical Center have discovered why mouse ES cells can be easily grown in a laboratory while other mammalian ES cells are difficult, if not impossible, to maintain. Female human embryos adjust the balance of X chromosomes before implantation Dutch researchers have found the first evidence that a process of inactivating the X chromosome during embryo development and implantation, which was known to occur in mice but unknown in humans, does, in fact, take place in human female embryos prior to implantation in the womb. MU scientists convert pigs' connective tissue cells into stem cells For years, proponents have touted the benefits of embryonic stem cell research, but the potential therapies still face hurdles. What do blood stem cells need to grow? Blood flow Blood stem cells literally go with the flow, according to a new report published as an immediate early publication in the journal Cell, a Cell Press journal, on May 13th. More Embryonic Stem Cell Current Events and Embryonic Stem Cell News Articles |
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