"In essence, we have built a replacement sphincter that we hope can one day benefit human patients. This is the first bioengineered sphincter made with both muscle and nerve cells, making it 'pre-wired' for placement in the body," said senior author Khalil N. Bitar, Ph.D., a professor of regenerative medicine at Wake Forest Baptist Medical Center's Institute for Regenerative Medicine. Bitar performed the work when he was on the University of Michigan faculty and it included a colleague from Emory University.
Sphincters are ring-like muscles that maintain constriction of a body passage. There are numerous sphincters in the human body, including those that control the release of urine and feces. There are actually two sphincters at the anus – one internal and one external. Fecal incontinence is the result of a weakened internal sphincter.
There is a high incidence of weakened internal fecal sphincters in older adults; and women who have had episiotomies during childbirth can also be affected. "Many individuals find themselves withdrawing from their social lives and attempting to hide the problem from their families, friends, and even their doctors," said Bitar. "Many people suffer without help."
Current options for repair of the internal anal sphincter include grafts of skeletal muscle, injectable silicone material or implantation of mechanical devices, all of which have high complication rates and limited success.
To engineer an internal anal sphincter in the laboratory, the researchers used a small biopsy from a human sphincter and isolated smooth muscle cells that were then multiplied in the lab. In a ring-shaped mold, these cells were layered with nerve cells isolated from mice to build the sphincter. The mold was placed in an incubator for nine days, allowing for tissue formation. The entire process took about six weeks.
Numerous laboratory tests of the engineered sphincters, including stimulating the nerve cells, showed normal tissue function, such as the ability to relax and contract. The sphincters were then implanted just under the skin of mice to determine how they would respond in the body. Mice with suppressed immune systems were selected so that there would be no issues with rejection.
After 25 days of implantation, each sphincter was re-tested and also compared with the animals' native sphincters. The engineered sphincters had developed a blood vessel supply and continued to function like native tissue.
"The engineered sphincters were physiologically similar to native tissue," said Bitar. "This takes us one step closer to realizing the goal of using a patient's own cells to engineer a replacement sphincter in the lab."
Bitar's team had previously shown that circular pieces of tissue made from sphincter muscle cells displayed characteristics of native sphincters. However, the tissue lacked the nerve cells required for normal function in the body.
"Our latest advance, a sphincter engineered with muscle and nerve cells, will allow us to 'connect' the engineered tissue with nerve pathways in the intestine," said Bitar.
Bitar's group will continue the research in more advanced research models. The ultimate goal is to harvest both muscle and nerve cells from a patient, build a pre-wired sphincter in the lab, and implant it back in the same patient. Using the patient's own cells would eliminate the risk of rejection.
"While we have numerous challenges to meet, we have crossed a major hurdle," said Bitar. "This proof of concept research suggests that this strategy may be useful for treating a variety of neuromuscular conditions of the intestine. In addition, it could potentially be applied to other diseases of sphincter muscles, including urinary incontinence."
Co-researchers were Robert Gilmont, Ph.D., Sita Somara, Ph.D., and lead author Shreya A. Raghavan, a Ph.D. candidate, all now at Wake Forest Baptist; Daniel Teitelbaum M.D., from the University of Michigan; and Shanthi Srinivasan, M.D., from Emory University.
Media Contacts: Karen Richardson, firstname.lastname@example.org, (336) 716-4453 or Main Number (336) 716-4587.
Wake Forest Baptist Medical Center is 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. Wake Forest School of Medicine is ranked among the nation's best medicine schools and is a leading national research center in fields such as regenerative medicine, cancer, neuroscience, aging, addiction and public health sciences. Wake Forest Baptist's clinical programs are consistently ranked as among the best in the country by U.S.News & World Report.
Karen Richardson | EurekAlert!
Researchers identify cause of hereditary skeletal muscle disorder
22.02.2017 | Klinikum der Universität München
Second cause of hidden hearing loss identified
20.02.2017 | Michigan Medicine - University of Michigan
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
22.02.2017 | Power and Electrical Engineering
22.02.2017 | Life Sciences
22.02.2017 | Physics and Astronomy