Tissue Engineering at Pratt

January 1, 2003

By Anu Kotha

(Kotha is a freshman at Pratt)

Within the next 10 years, more than 70 million people are going to join the ranks of seniors. As they age, they will face several medical problems. One such problem concerns joints. The articular cartilage that allows bones to smoothly move over each other wears down with time. Unlike most tissues in the body, articular cartilage cannot heal itself. Due to the loss of this cartilage, bones rub against each other and cause tremendous pain at the joints, especially at the knee.

At this time, the best option to alleviate serious pain is knee-joint replacement. Approximately 200,000 total knee joint operations are performed annually at a cost of about $26,000 per replacement. Usually these artificial joints last only 10-15 years. A less painful option may be available in future. This solution is brewing at Duke University.

Researchers under the leadership Professor Lori Setton are working on a biomaterial that can be implanted at the knee joint. The biomaterial, Elastin-like polypeptides (ELP), has unique properties that make it attractive as an injectable scaffold for cartilaginous tissue repair. These artificial polypeptides are native to the elastin found in muscle, cartilage, and other soft tissues, and thus can evade detection by the immune system. This decreases the chances of rejection of the biomaterial by the body. When in the gel-like state, ELPs possess mechanical properties that approach that of native cartilaginous tissues. Setton’s lab has genetically modified ELPs so that they will transition from liquid to the gel-like coacervate when inside the human body. ELPs, however, lack the strength to withstand the pressure that occurs at the knees. The lab is working on strengthening ELPs by crosslinking these polypeptides in the presence of enzymes or visible light from lasers. Setton was recently awarded a $1.45 million grant for this tissue cartilage work.

If all works well, according to Setton, the lab may have a biomaterial that attains physical properties of cartilaginous tissues for the repair of not only knees but various joints and invertebral discs. This goal of creating biomaterials for the purpose of alternative therapies for minimally invasive intervention to inhibit the progression of disease and eliminate total joint replacement is one of the hallmarks of the field of tissue engineering.

Tissue engineering is a rapidly expanding area combining the disciplines of biology and engineering to solve medical problems. The goal is to develop and manipulate laboratory-grown molecules, cells, tissues or organs for the purpose of restoring, maintaining or improving the function of human tissues or organs. Commercially produced skin is already available to treat patients with diabetic ulcers and burns. Scientists have engineered blood vessels from adult pigs’ arteries to act like human vessels. In 5-10 years, regeneration of such blood vessels, bone, and skin may become routine. Tissue engineering offers the possibilities of building deficient osteoporotic bone or stopping cancer cells by choking off their blood supply. This field is attractive for industry since new developments for treatments of diseases will be relatively inexpensive compared to today’s methods.

As seen with the development of cartilage, tissue engineering may provide us a future where body parts are available to purchase. Though this scenario is years away, the possibility of having new options to treat diseases is exciting and offers hope for the betterment of human health.