Dr. El-Amin prepares a polyactic acid mixture that will become a scaffold upon which to grow tissues.
Even with preventive measures and cutting edge treatments, severe orthopaedic injuries necessitate operations and possible replacement of ligaments, hips, even bone. Synthetic transplants made of metal or plastic can work, but the SIU Division of Orthopaedics envisions something even better.
Tissue engineering takes the person’s tissues or stem cells and grows them around a scaﬀold to eventually become an organ, ligament, or bone. Tissue engineering can help meet the organ and tissue shortage without the complications that can result from possible rejection or disease transfer that is possible with transplants.
SIU orthopaedic surgeon Saadiq El-Amin, III, M.D., Ph.D., brings expertise in tissue engineering to regenerate bone and ligaments. Orthopaedics, he says, already has been one of the leaders of tissue engineering products, including biodegradable sutures, pins, screws, and bone grafts that promote tissue growth.
“Tissue engineering is the next level of science,” says Dr. El-Amin, who has several patents for tissue engineered polymeric scaffolds. Tissue engineering can support a graft or create another graft that allows the person’s own tissue to grow — and those tissues are stronger than artiﬁcial tissues.
For fractures that won’t heal, a bone substitute is usually necessary to take some bone from another site for grafting. This leads to high surgical costs, pain, and risk of infection. Bone substitutes from cadavers or man-made materials such as metals, plastics, or ceramics may not generate tissue and growth over time. As an alternative, tissue-engineered bone may alleviate some of these problems. “This would have a huge impact,” Dr. El-Amin says. He ﬁrst worked on tissue engineering at MIT with Dr. Cato Laurencin. As a fellow at Hospital for Special Surgery, he collaborated with Drexel University to design a tissue-engineered meniscus. This work has been accepted by the Orthopaedic Research Society.
ACL injuries — the number one ligament that athletes rupture that may end their careers — could be treated with tissue-engineered ligaments. Dr. El-Amin also hopes to reconstruct elbow ligaments and rotator cuﬀ tissues.
In an innovative method, Dr. El-Amin uses mesenchymal stem cells — multipotent stem cells derived from a person’s body that can become cartilage, tendon, muscle, or bone. “Everyone has these stem cells in their bodies,” he explains. Stem cells buried within fat cells also are being studied for tissue engineering. Yes, scientists have found that adipose tissue contain stem cells.
Here’s the design Dr. El-Amin envisions. A polymer created from hydrogel technology and a polyglycolic acid (basic sugar molecules) becomes a scaﬀold. A patient’s primordial stem cells (mesenchymal or adipose (fat) cells) are placed on the scaﬀold inside the body. The cells naturally grow onto the scaﬀold, and the lactic acid cycle of the body naturally absorbs the scaﬀold. This technique would apply to the meniscus, the ACL, or even bone. “The concept is simple, but getting there is more diﬃcult.” His labs are designing and synthesizing polymeric materials — a ﬁrst for central Illinois.
Using a person’s own cells — tissue-engineered matrices — is an innovative technique and would prove more cost eﬀective than using products already on the market. “It also would create new job opportunities for the area,” he explains. Dr. El-Amin has several patents for similar concepts of using polymeric materials for scaﬀolds and an injectable bone material for spinal fusion. The SIU School of Engineering in Carbondale will collaborate on projects.
SIU School of Medicine’s Division of Plastic Surgery has worked on tissue engineering for years to grow skin and ears (see ASPECTS 22-4). Dr. El-Amin will collaborate with Michael Neumeister, M.D., chair of the plastic surgery division, and also plans to collaborate with OB/GYN to develop polymers to regenerate the female pelvic ﬂoor. He also foresees tissue engineering projects to beneﬁt HIV research, creating peptides to help the immune system ﬁght the virus.
“This research can ultimately provide an alternative form of care that can help reduce overall morbidity and mortality as well as reduce the costs,” Dr. El-Amin says. “Tissue engineering will provide multiple options, leading to better quality of care. Patients will be able to get back to their lives faster and be happier.”