With substantial advancement of technology in the last several years, there has been a whirlwind of developments in the field of regenerative medicine. So far, we’ve heard of fully-functional ear, nose, urinary bladder and even trachea, being regenerated from human stem cells. Well scientists, at the Duke University, have finally managed to grow what is likely the first ever contracting human muscle, in a laboratory. Closely resembling living cells in its form as well as function, the lab-created tissue has been shown to respond to a variety of biochemical stimuli and also drugs.
The research, recently published in the eLife journal, was headed by a Duke University professor of the department of biomedical engineering, Nenad Bursac and a postdoctoral fellow named Lauran Madden. According to the team, the regenerated tissue will allow researchers and pharmaceutical companies to analyse diseases and also the effectiveness of specific drugs in combating such diseases, in a laboratory outside the human body. Speaking about the importance of the project, Bursac said:
The beauty of this work is that it can serve as a test bed for clinical trials in a dish. We are working to test drugs’ efficacy and safety without jeopardizing a patient’s health and also to reproduce the functional and biochemical signals of diseases—especially rare ones and those that make taking muscle biopsies difficult.
Based on their experience in developing bioartificial tissues from animal cells, the team chose a human cell sample that had already passed the stem cell stage, but had not yet grown into muscle tissue. The sample was then placed onto a special three-dimensional scaffolding, containing a nutrient-rich solution of specific density. The setup allowed the cells to reorganize themselves into fully-operative muscle fibers. Following this, a multitude of tests were conducted to ascertain the similarity between the regenerated skeletal muscle and the actual tissues present inside the human body. Madden said:
We 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 cells.
When subjected to an external electrical signal, the tissue exhibited uniform contractions; marking the first time that a lab-grown tissue has accomplished such a feat. In order to check if it could be used for drug testing, the muscle’s response to different medicines was closely observed and recorded. For instance, administering higher doses of statin, a medicine that reduces cholesterol, caused the sample to undergo fat accumulation. Furthermore, the team was able to detect increased contractions of the muscle, under the influence of clenbuterol, a performance improving medicine used by athletes.
Although developed artificially in a laboratory, the skeletal muscle tissue showed remarkable resemblance with living human cells, especially with regard to its response towards particular drugs. The fat accumulation as well as the increased contraction, of the muscle, are in fact effects that the medicines generate only in case of human patients. Currently, the researchers are looking for ways to recreate the same contracting muscle tissue from induced pluripotent stem cells (iPSCs). Unlike biopsied cells, the iPSCs are capable of giving birth to all other types of human cells. Bursac was reported saying:
One of our goals is to use this method to provide personalized medicine to. 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… There are a some diseases, like Duchenne Muscular Dystrophy for example, that make taking muscle biopsies difficult. If 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.