{"327601":{"#nid":"327601","#data":{"type":"news","title":"Platelets modulate clotting behavior by \u201cfeeling\u201d their surroundings","body":[{"value":"\u003Cp\u003EPlatelets, the tiny cell fragments whose job it is to stop bleeding, are very simple. They don\u2019t have a cell nucleus. But they can \u201cfeel\u201d the physical environment around them, researchers at Emory University and Georgia Tech have discovered.\u003C\/p\u003E\u003Cp\u003EPlatelets respond to surfaces with greater stiffness by increasing their stickiness, the degree to which they \u201cturn on\u201d other platelets and other components of the clotting system, the researchers found.\u003C\/p\u003E\u003Cp\u003E\u201cPlatelets are smarter than we give them credit for, in that they are able to sense the physical characteristics of their environment and respond in a graduated way,\u201d said Wilbur Lam, M.D., Ph.D., assistant professor in the Department of Pediatrics at Emory University School of Medicine and in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University.\u003C\/p\u003E\u003Cp\u003EThe results are published in the journal \u003Cem\u003EProceedings of the National Academy of Sciences\u003C\/em\u003E. The first author of the paper is research associate Yongzhi Qiu. Lam is also a physician in the Aflac Cancer and Blood Disorders Center, Children\u2019s Healthcare of Atlanta.\u003C\/p\u003E\u003Cp\u003EThe researchers\u2019 findings could influence the design of medical devices, because when platelets grab onto the surfaces of catheters and medical implants, they tend to form clots, a major problem for patient care.\u003C\/p\u003E\u003Cp\u003EModifying the stiffness of materials used in these devices could reduce clot formation, the authors suggest. The results could also guide the refinement of blood thinning drugs, which are prescribed to millions to reduce the risk of heart attack or stroke.\u003C\/p\u003E\u003Cp\u003EThe team was able to separate physical and biochemical effects on platelet behavior by forming polymer gels with different degrees of stiffness, and then overlaying them each with the same coating of fibrinogen, a sticky protein critical for blood clotting. Fibrinogen is the precursor for fibrin, which forms a mesh of insoluble strands in a blood clot.\u003C\/p\u003E\u003Cp\u003EWith stiffer gels, platelets spread out more and become more activated. This behavior is most pronounced when the concentration of fibrinogen is relatively low, the researchers found.\u003C\/p\u003E\u003Cp\u003E\u201cThis variability helps to explain platelet behavior in the 3D context of a clot in the body, which can be quite heterogenous in makeup,\u201d Lam said.\u003C\/p\u003E\u003Cp\u003EQiu and colleagues were also able to dissect platelet biochemistry by allowing the platelets to adhere and then spread on the various gels under the influence of drugs that interfere with different biochemical steps.\u003C\/p\u003E\u003Cp\u003EProteins called integrins, which engage the fibrinogen, and the protein Rac1 are involved in the initial mechanical sensing during adhesion, while myosin and actin, components of the cytoskeleton, are responsible for platelet spreading.\u003C\/p\u003E\u003Cp\u003E\u201cWe found that the initial adhesion and later spreading are separable, because different biochemical pathways are involved in each step,\u201d Lam said. \u201cOur data show that mechanosensing can occur and plays important roles even when the cellular structural building blocks are fairly basic, even when the nucleus is absent.\u201d\u003C\/p\u003E\u003Cp\u003EThe research was supported by the National Science Foundation, the American Heart Association, the National Heart Lung \u0026amp; Blood Institute (U54HL112309, R01HL121264) and the National Eye Institute (PN2EY018244).\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: Emory University: Quinn Eastman (\u003Ca href=\u0022mailto:qeastma@emory.edu\u0022\u003Eqeastma@emory.edu\u003C\/a\u003E) (404-727-7829) or Georgia Tech: John Toon (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) (404-894-6986).\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: Quinn Eastman\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EPlatelets, the tiny cell fragments whose job it is to stop bleeding, are very simple. They don\u2019t have a cell nucleus. But they can \u201cfeel\u201d the physical environment around them, researchers at Emory University and Georgia Tech have discovered.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Blood platelets can \u0022feel\u0022 the physical environment around them, researchers have learned."}],"uid":"27303","created_gmt":"2014-09-22 14:52:06","changed_gmt":"2016-10-08 03:17:07","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2014-09-22T00:00:00-04:00","iso_date":"2014-09-22T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"327581":{"id":"327581","type":"image","title":"Platelet clotting behavior","body":null,"created":"1449245064","gmt_created":"2015-12-04 16:04:24","changed":"1475895039","gmt_changed":"2016-10-08 02:50:39","alt":"Platelet clotting behavior","file":{"fid":"200257","name":"platelets-lam-qui.jpg","image_path":"\/sites\/default\/files\/images\/platelets-lam-qui_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/platelets-lam-qui_0.jpg","mime":"image\/jpeg","size":1120441,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/platelets-lam-qui_0.jpg?itok=KLkh4JeU"}},"327591":{"id":"327591","type":"image","title":"Platelet spreading","body":null,"created":"1449245064","gmt_created":"2015-12-04 16:04:24","changed":"1475895039","gmt_changed":"2016-10-08 02:50:39","alt":"Platelet spreading","file":{"fid":"200258","name":"plateletsspread.png","image_path":"\/sites\/default\/files\/images\/plateletsspread_0.png","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/plateletsspread_0.png","mime":"image\/png","size":149607,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/plateletsspread_0.png?itok=yNks7LoS"}}},"media_ids":["327581","327591"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"146","name":"Life Sciences and Biology"},{"id":"135","name":"Research"}],"keywords":[{"id":"1440","name":"blood"},{"id":"102021","name":"clotting"},{"id":"36131","name":"platelets"},{"id":"171368","name":"surface"},{"id":"3264","name":"Wallace H. Coulter Department of Biomedical Engineering"},{"id":"14681","name":"Wilbur Lam"}],"core_research_areas":[{"id":"39441","name":"Bioengineering and Bioscience"}],"news_room_topics":[{"id":"71891","name":"Health and Medicine"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}