{"48923":{"#nid":"48923","#data":{"type":"news","title":"Delivering Stem Cells Improves Repair of Major Bone Injuries in Rats","body":[{"value":"\u003Cp\u003EA study published this week reinforces the potential value of stem cells in repairing major injuries involving the loss of bone structure.  \u003C\/p\u003E\n\u003Cp\u003EThe study shows that delivering stem cells on a polymer scaffold to treat large areas of missing bone leads to improved bone formation and better mechanical properties compared to treatment with the scaffold alone. This type of therapeutic treatment could be a potential alternative to bone grafting operations.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Massive bone injuries are among the most challenging problems that orthopedic surgeons face, and they are commonly seen as a result of accidents as well as in soldiers returning from war,\u0022 said the study\u0027s lead author Robert Guldberg, a professor in Georgia Tech\u0027s Woodruff School of Mechanical Engineering. \u0022This study shows that there is promise in treating these injuries by delivering stem cells to the injury site. These are injuries that would not heal without significant medical intervention.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EDetails of the research were published in the early edition of the journal \u003Cem\u003EProceedings of the National Academy of Sciences\u003C\/em\u003E on January 11, 2010. This work was funded by the National Institutes of Health and the National Science Foundation.\n\u003C\/p\u003E\n\u003Cp\u003EThe study was conducted in rats in which two bone gaps eight millimeters in length were created to simulate massive injuries. One gap was treated with a polymer scaffold seeded with stem cells and the other with scaffold only. The results showed that injuries treated with the stem cell scaffolds showed significantly more bone growth than injuries treated with scaffolds only. \n\u003C\/p\u003E\n\u003Cp\u003EGuldberg and mechanical engineering graduate student Kenneth Dupont experimented with scaffolds containing two different types of human stem cells -- bone marrow-derived mesenchymal adult stem cells and amniotic fluid fetal stem cells. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022We were able to directly evaluate the therapeutic potential of human stem cells to repair large bone defects by implanting them into rats with a reduced immune system,\u0022 explained Guldberg, who is also the director of the Petit Institute for Bioengineering and Bioscience at Georgia Tech.\u003C\/p\u003E\n\u003Cp\u003EMicro-CT measurements showed no significant differences in bone regeneration between the two stem cell groups. However, combining the two types of stem cells produced significantly higher bone volume and strength compared to scaffolds without cellular augmentation.\n\u003C\/p\u003E\n\u003Cp\u003EAlthough stem cell delivery significantly enhanced bone growth and biomechanical properties, it was not able to consistently repair the injury. Eight weeks after the treatment, new bone bridged the gaps in four of nine defects treated with scaffolds seeded with adult stem cells, one of nine defects treated with scaffolds seeded with fetal stem cells, and none of the defects treated with the scaffold alone.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We thought that the functional regeneration of the bone defects may have been limited by stem cells migrating away from the injury site, so we decided to investigate the fate and distribution of the delivered cells,\u0022 said Guldberg.\n\u003C\/p\u003E\n\u003Cp\u003ETo do this, Guldberg labeled stem cells with fluorescent quantum dots -- nanometer-scale particles that emit light when excited by near-infrared radiation -- to track the distribution of stem cells after delivery on the scaffolds and completed the same experiments as previously described. \n\u003C\/p\u003E\n\u003Cp\u003EThroughout the entire study, the researchers observed significant fluorescence at the stem cell scaffold sites. However, beginning seven to 10 days after treatment, signals appeared at the scaffold-only sites. Additional analysis with immunostaining revealed that the quantum dots present at the scaffold-only sites were contained in inflammatory cells called macrophages that had taken up quantum dots released from dead stem cells.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022While our overall study shows that stem cell therapy has a lot of promise for treating massive bone defects, this experiment shows that we still need to develop an improved way of delivering the stem cells so that they stay alive longer and thus remain at the injury site longer,\u0022 explained Guldberg.\u003C\/p\u003E\n\u003Cp\u003EThe researchers also found that the quantum dots diminished the function of the transplanted stem cells and thus their therapeutic effect. When the stem cells were labeled with quantum dots, the results showed a failure to enhance bone formation or bridge defects. However, the same low concentration of quantum dots did not affect cell viability or the ability of the stem cells to become bone cells in laboratory studies. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022Although in vitro laboratory studies remain important, this work provides further evidence that well-characterized in vivo models are necessary to test the ability of regenerative tissue strategies to effectively integrate and restore function in complex living organisms,\u0022 added Guldberg. \u0022Improved methods of non-invasive cell tracking that do not alter cell function in vivo are needed to optimize stem cell delivery strategies and compare the effectiveness of different stem cell sources for tissue regeneration.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EGuldberg is currently exploring alternative cell tracking methods, such as genetically modifying the stem cells to express green fluorescent protein and\/or other luminescent enzymes such as luciferase. He is also investigating the addition of programming cues to the scaffold that will direct the stem cells to differentiate into bone cells. These signals may be particularly effective for fetal stem cells, which are believed to be more primitive than adult stem cells, according to Guldberg. \n\u003C\/p\u003E\n\u003Cp\u003ELessons learned from the current work are also being applied to develop effective stem cell therapies for severe composite injuries to multiple tissues including bone, nerve, vasculature and muscle. This follow-on work is being conducted in the Georgia Tech Center for Advanced Bioengineering for Soldier Survivability in collaboration with Ravi Bellamkonda and Barbara Boyan, professors in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University.\n\u003C\/p\u003E\n\u003Cp\u003EOther authors on the paper include Andres Garcia, professor and Woodruff Faculty Fellow in Georgia Tech\u0027s Woodruff School of Mechanical Engineering and the Petit Institute for Bioengineering and Bioscience; Georgia Tech research scientist Hazel Stevens, Georgia Tech graduate student Joel Boerckel; and National University of Ireland medical student Kapil Sharma.\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cem\u003EThis work was funded by grant number R01-AR051336 from the National Institutes of Health (NIH) and by grant number EEC-9731643 from the National Science Foundation (NSF). The content is solely the responsibility of the principal investigator and does not necessarily represent the official views of the NIH or NSF.\u003C\/em\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\n\u003C\/strong\u003E\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts:\u003C\/strong\u003E Abby Vogel (avogel@gatech.edu; 404-385-3364) or John Toon (jtoon@gatech.edu; 404-894-6986).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter:\u003C\/strong\u003E Abby Vogel\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"A new study published this week shows that delivering stem cells on a polymer scaffold to treat large areas of missing bone leads to improved bone formation and better mechanical properties compared to treatment with scaffold alone.","format":"limited_html"}],"field_summary_sentence":[{"value":"Study reinforces potential value of stem cells to repair bone in"}],"uid":"27206","created_gmt":"2010-01-11 01:00:00","changed_gmt":"2016-10-08 03:04:04","author":"Abby Vogel Robinson","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-01-11T00:00:00-05:00","iso_date":"2010-01-11T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"48924":{"id":"48924","type":"image","title":"Robert Guldberg bone regeneration","body":null,"created":"1449175408","gmt_created":"2015-12-03 20:43:28","changed":"1475894463","gmt_changed":"2016-10-08 02:41:03","alt":"Robert Guldberg bone regeneration","file":{"fid":"101291","name":"try39853.jpg","image_path":"\/sites\/default\/files\/images\/try39853_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/try39853_0.jpg","mime":"image\/jpeg","size":1255705,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/try39853_0.jpg?itok=qv-fHLYD"}},"48925":{"id":"48925","type":"image","title":"Bone regeneration with stem cell scaffold","body":null,"created":"1449175408","gmt_created":"2015-12-03 20:43:28","changed":"1475894463","gmt_changed":"2016-10-08 02:41:03","alt":"Bone regeneration with stem cell scaffold","file":{"fid":"101292","name":"tyd39853.jpg","image_path":"\/sites\/default\/files\/images\/tyd39853_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/tyd39853_0.jpg","mime":"image\/jpeg","size":405535,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tyd39853_0.jpg?itok=ZMJG3doK"}},"48926":{"id":"48926","type":"image","title":"Robert Guldberg bone regeneration","body":null,"created":"1449175408","gmt_created":"2015-12-03 20:43:28","changed":"1475894463","gmt_changed":"2016-10-08 02:41:03","alt":"Robert Guldberg bone regeneration","file":{"fid":"101293","name":"the39853.jpg","image_path":"\/sites\/default\/files\/images\/the39853_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/the39853_0.jpg","mime":"image\/jpeg","size":1050118,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/the39853_0.jpg?itok=VAKE7nTl"}}},"media_ids":["48924","48925","48926"],"related_links":[{"url":"http:\/\/www.me.gatech.edu\/faculty\/guldberg.shtml","title":"Robert Guldberg"},{"url":"http:\/\/www.me.gatech.edu\/","title":"George W. Woodruff School of Mechanical Engineering"},{"url":"http:\/\/www.ibb.gatech.edu\/","title":"Petit Institute for Bioengineering and Bioscience"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"135","name":"Research"}],"keywords":[{"id":"8233","name":"amniotic fluid fetal stem cells"},{"id":"530","name":"bone"},{"id":"8227","name":"bone defect"},{"id":"8231","name":"Bone Marrow Derived Stem Cells"},{"id":"8226","name":"Bone Regeneration"},{"id":"8225","name":"Bone Repair"},{"id":"8232","name":"fetal stem cells"},{"id":"6891","name":"fluorescence"},{"id":"8230","name":"Mesenchymal Stem Cells"},{"id":"8228","name":"Orthopedics"},{"id":"8229","name":"polymer scaffold"},{"id":"2363","name":"quantum dots"},{"id":"1489","name":"Regenerative Medicine"},{"id":"167413","name":"Stem Cell"},{"id":"167139","name":"Stem Cell Research"},{"id":"167130","name":"Stem Cells"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EAbby Vogel\u003C\/strong\u003E\u003Cbr \/\u003EResearch News and Publications\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=avogel6\u0022\u003EContact Abby Vogel\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-385-3364\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["avogel@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}