The researchers at Duke University have grown human skeletal muscle in the lab that may help to test new drugs and study diseases in functioning human muscle outside the human body.
The lab-grown tissue is found to be similar to the native tissue that contracts and responds to external stimuli such as electrical pulses, biochemical signals and pharmaceuticals.
“We are working to test drugs’ efficacy and safety without jeopardising a patient’s health and also to reproduce the functional and biochemical signals of diseases including rare ones,” explained Nenad Bursac, associate professor of biomedical engineering at Duke University.
Bursac and Lauran Madden, the researchers, began with a small sample of human cells that had already progressed beyond stem cells but hadn’t yet become muscle tissue. They expanded these “myogenic precursors” by more than a 1000-fold, and then put them into a supportive, 3-D scaffolding filled with a nourishing gel that allowed them to form aligned and functioning muscle fibers.
Amid, Madden subjected the new muscle to a barrage of tests to determine how closely it resembled native tissue inside a human body. “We have a lot of experience making bio-artifical muscles from animal cells in the laboratory, and it still took us a year of adjusting variables like cell and gel density and optimizing thec ulture matrix and media to make this work with human muscle cells,” she said.
She found that the muscles robustly contracted in response to electrical stimuli – a first for human muscle grown in a laboratory. She also showed that the signalling 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, the duo studied its response to a variety of drugs, including statins used to lower cholesterol. The effects of the drugs matched those seen in human patients.
“One of our goals is to use this method to provide personalised medicine to patients,” said Bursac, “We 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.”
The study appeared in the open-access journal eLife.