"While the body has a capacity to repair small defects in skeletal muscle, the only option for larger defects is to surgically move muscle from one part of the body to another. This is like robbing Peter to pay Paul," said George Christ, Ph.D., a professor at Wake Forest Baptist Medical Center's Institute for Regenerative Medicine. "Rather than moving existing muscle, our aim is to help the body grow new muscle."
In the current issue of Tissue Engineering Part A, Christ and team build on their prior work and report their second round of experiments showing that placing cells derived from muscle tissue on a strip of biocompatible material – and then "exercising" the strip in the lab – results in a muscle-like implant that can prompt muscle regeneration and significant functional recovery. The researchers hope the treatment can one day help patients with muscle defects ranging from cleft lip and palate to those caused by traumatic injuries or surgery.
For the study, small samples of muscle tissue from rats and mice were processed to extract cells, which were then multiplied in the lab. The cells, at a rate of 1 million per square centimeter, were placed onto strips of a natural biological material. The material, derived from pig bladder with all cells removed, is known to be compatible with the body.
Next, the strips were placed in a computer-controlled device that slowly expands and contracts – essentially "educating" the implants on how to perform in the body. This cyclic stretching and relaxation occurred three times per minute for the first five minutes of each hour for about a week. In the current study, the scientists tried several different protocols, such as adding more cells to the strips during the exercise process.
The next step was implanting the strips in mice with about half of a large muscle in the back (latissimus dorsi) removed to create functional impairment. While the strips are "muscle-like" at the time of implantation, they are not yet functional. Implantation in the body – sometimes referred to as "nature's incubator" – prompts further development.
The goal of the project was to speed up the body's natural recovery process as well as prompt the development of new muscle tissue. The scientists compared four groups of mice. One group received no surgical repair. The other groups received implants prepared in one of three ways: one was not exercised before implantation, one was exercised for five to seven days, and one had extra cells added midway through the exercise process. The results showed that exercising the implants made a significant difference in both muscle development and function.
"The implant that wasn't exercised, or pre-conditioned, was able to accelerate the repair process, but recovery then stopped," said Christ. "On the other hand, when you exercise the implant, there is a more prolonged and extensive functional recovery. Through exercising the implant, you can increase both the rate and the magnitude of the recovery."
A variety of laboratory tests were used to measure results. A test of muscle force at two months, for example, showed that animals who received the implants with extra cells added had a threefold increase in absolute force compared to animals whose muscle damage was not repaired. The force-producing capacity of muscle is what determines the ability to perform everyday tasks.
"If these same results were repeated in humans, the recovery in function would clearly be considered significant," said Christ. "Within two months after implantation, the force generated by the repaired muscle is 70 percent that of native tissue, compared to 30 percent in animals that didn't receive repair."
The results also showed that new muscle tissue developed both in the implant, as well as in the area where the implant and native tissue met, suggesting that the implant works by accelerating the body's natural healing response, as well as by prompting the growth of new muscle tissue.
The researchers hope to evaluate the treatment in patients who need additional surgery for cleft lip and palate, a relatively common birth defect where there is a gap in muscle tissue required for normal facial development. These children commonly undergo multiple surgeries that involve moving muscle from one location to another or stretching existing muscle tissue to cover the tissue gap. The implant used in the current research is almost exactly the size required for these surgeries.
"As a surgeon I am excited about the advances in tissue-engineered muscle repair, which have been very promising and exciting potential in the surgical correction of both functional and cosmetic deformities in cleft lip and cleft palate" said Phillip N. Freeman, M.D., D.M.D., associate professor of Oral and Maxillofacial Surgery at the University of Texas Health Science Center at Houston. "Current technology does not address the inadequate muscle volume or function that is necessary for complete correction in 20 percent to 30 percent of cases. With this innovative technology there is the potential to make significant advances in more complete corrections of cleft lip and cleft palate patients."
The technology was originally developed under the Armed Forces Institute of Regenerative Medicine (AFIRM) with funding from the Department of Defense and the National Institutes of Health. The sponsor of the current research was the Telemedicine & Advanced Technology Research Center. A longer-term goal is to use the implant – in combination with other tissue-engineered implants and technologies being developed as part of AFIRM -- to treat the severe head and facial injuries sustained by military personnel. For example, AFIRM-sponsored projects under way to engineer bone, skin and nerve may one day be combined to make a "composite" tissue.
Co-researchers were Benjamin T. Corona, Ph.D., lead author, Masood A. Machingal, Ph.D., Tracy Criswell, Ph.D., Manasi Vadhavkar, MD., Ashley C. Dannahower, Christopher Bergman, and Weixin Zhao, M.D., all from Wake Forest Baptist.
Media Contacts: Karen Richardson, email@example.com, (336) 716-4453 or Main Number (336) 716-4587.
About the Wake Forest Institute for Regenerative Medicine
The Wake Forest Institute for Regenerative Medicine is dedicated to the discovery, development and clinical translation of regenerative medicine technologies. The institute has used biomaterials alone, cell therapies, and engineered tissues and organs for the treatment of patients with injury or disease. Institute scientists were the first in the world to engineer a replacement organ in the laboratory that was successfully implanted in patients. The Institute is based at Wake Forest Baptist Medical Center, a fully integrated academic medical center located in Winston-Salem, North Carolina. The institution comprises the medical education and research components of Wake Forest School of Medicine, the integrated clinical structure and consumer brand Wake Forest Baptist Health, which includes North Carolina Baptist Hospital and Brenner Children's Hospital, the commercialization of research discoveries through the Piedmont Triad Research Park, as well a network of affiliated community based hospitals, physician practices, outpatient services and other medical facilities.
Karen Richardson | EurekAlert!
Plant inspiration could lead to flexible electronics
22.06.2017 | American Chemical Society
A rhodium-based catalyst for making organosilicon using less precious metal
22.06.2017 | Tokyo Institute of Technology
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.
New Manufacturing Technologies for New Products
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
22.06.2017 | Life Sciences
22.06.2017 | Materials Sciences
22.06.2017 | Materials Sciences