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www.technology.org 2015 0000201.txt

#First contracting human muscle grown in laboratory The lab-grown tissue should soon allow researchers to test new drugs and study diseases in functioning human muscle outside of the human body. The study was led by Nenad Bursac associate professor of biomedical engineering at Duke university and Lauran Madden a postdoctoral researcher in Bursac laboratory. It appears January 13 in the open-access journal elife. he beauty of this work is that it can serve as a test bed for clinical trials in a dishsaid Bursac. e are working to test drugsefficacy and safety without jeopardizing a patient health and also to reproduce the functional and biochemical signals of diseasesspecially rare ones and those that make taking muscle biopsies difficult. ursac and Madden started with a small sample of human cells that had progressed already beyond stem cells but hadn yet become muscle tissue. They expanded these yogenic precursorsby more than a 1000-fold and then put them into a supportive 3d scaffolding filled with a nourishing gel that allowed them to form aligned and functioning muscle fibers. e have a lot of experience making bioartifical muscles from animal cells in the laboratory and it still took us a year of adjusting variables like cell and gel density and optimizing the culture matrix and media to make this work with human muscle cellssaid Madden. Madden subjected the new muscle to a barrage of tests to determine how closely it resembled native tissue inside a human body. She found that the muscles robustly contracted in response to electrical stimuli first for human muscle grown in a laboratory. She also showed that the signaling pathways allowing nerves to activate the muscle were intact and functional. To see if the muscle could be used as a proxy for medical tests Bursac and Madden studied its response to a variety of drugs including statins used to lower cholesterol and clenbuterol a drug known to be used off-label as a performance enhancer for athletes. The effects of the drugs matched those seen in human patients. The statins had a dose-dependent response causing abnormal fat accumulation at high concentrations. Clenbuterol showed a narrow beneficial window for increased contraction. Both of these effects have been documented in humans. Clenbuterol does not harm muscle tissue in rodents at those doses showing the lab-grown muscle was giving a truly human response. ne of our goals is to use this method to provide personalized medicine to patientssaid Bursac. e can take a biopsy from each patient grow many new muscles to use as test samples and experiment to see which drugs would work best for each person. his goal may not be far away; Bursac is already working on a study with clinicians at Duke Medicinencluding Dwight Koeberl associate professor of pediatricso try to correlate efficacy of drugs in patients with the effects on lab-grown muscles. Bursac#s group is also trying to grow contracting human muscles using induced pluripotent stem cells instead of biopsied cells. here are a some diseases like Duchenne Muscular dystrophy for example that make taking muscle biopsies difficultsaid Bursac. f we could grow working testable muscles from induced pluripotent stem cells we could take one skin or blood sample and never have to bother the patient again. ther investigators involved in this study include George Truskey the R. Eugene and Susie E. Goodson Professor of Biomedical engineering and senior associate dean for research for the Pratt School of engineering and William Krauss professor of biomedical engineering medicine and nursing at Duke university. The research was supported by NIH Grants R01ar055226 and R01ar065873 from the National Institute of Arthritis and Musculoskeletal and Skin disease and UH2TR000505 from the NIH Common Fund for the Microphysiological Systems Initiative. Source: Duke university By Ken Kinger n

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