History

     There are references to tissue engineering long before the term even existed. Many point to the Renaissance painting "The Healing  of Justinian by Saint Cosmas and Saint Damian" as the first example of Tissue Engineering in the human mind. In 1438, Angelico Fra depicted two saints healing a wounded soldier by replacing his leg with what appears to be a Homograft limb, which means that the limb is grown outside using the patient's own cells. This is not unlike the present day organ growing ideas. However, the oldest sign of something that resembles what we now know as Tissue Engineering comes from the Bible. As explained earlier, God turning one of man's ribs into a woman truly is the first example of growing human parts out of the body.

     The true commencement of the field of tissue engineering was in the 1970's when a pediatric orthopedic surgeon at the Children's Hospital, W.  T. Green, MD tried to create cartilage and implant this into a mouse. Though the experiment itself was a failure, the doctor was optimistic because he believed that the advent of biocompatible materials would help in creating scaffolds in which to transplant cells. Several years later, two doctors of the Massachusetts General Hospital and MIT worked together to create a skin substitute by using a collagen matrix to support the growth of skin cells. These skin cells were later successfully transferred to burn patients. A breakthrough occured in the mid-1980's when Dr. Vacanti approached Dr. Langler of MIT about designing appropriate scaffolds rather than using natrually available scaffolds, whose chemical and physical properties could not be controlled. The use of these natural scaffolds led to unpredictable results. Dr. Vacanti designed and conducted many thorough studies attempting to generate tissue surrogates. He used a branching network of synthetic biocompatible and biodegradable polymers as the scaffolds, which were then seeded with viable cells. His original paper in 1988 showed the world the promise of this up and coming field. Five years later, he published, with Dr. Langer, a paper that might be the most cited work in Tissue Engineering.

    Soon, Tissue Engineering spread all over the world and an organizing body was created. The Tissue Engineering Society was created in 1994 and incorporated into the Massachusetts state government in 1996. Initially meetings were held bi-annually, but as the organization grew and incorporated associations from all over the world, it started having anual meetings. It soon became TERMIS (Tissue Engineering Regenerative Medicine International Society). Along with the society, a new journal was created in 1994 called "Tissue Engineering."

     Perhaps the most famous example of Tissue Engineering is the auriculosaurus, which was a mouse with what appears to a human ear (the ear is actually that of a cow) . However, there have been many other successful examples of tissue engineering. Cartilage, skin, and pulmonary arteries were grown in the mid-'90s using the recently developed scaffolding technologies.

     The first human patient was a young boy with Polands Syndrome in 1991. He didn't have cartilage in his chest to protect his ribs nor a sternum to divide his ribs. The only thing protecting his chest was his skin. If he ever got hit in the chest, he would probably lose his life. As a baseball pitcher, this teenager really needed a new chest. By taking some of his cartilage, doctors were able to grow some cartilage to put into the boy's chest. His Poland's syndrome was effectively cured. In 1998, an industrial worker lost his thumb, which doctors were able to grow and place on his hand.

Recently, Dr. Atala has grown many organs in his lab, but these organs have not been implanted into a human. Using cells from patients, Dr. Atala has grown pulsing blood vessels, beating heart valves, and swollen bladders. These cells are often from the organ itself. However, this approach does not work for pancreas, liver, or nerve cells. Dr. Atala recently discovered that he could use cells taken from amniotic fluid to grow some liver cells. To grow organs such as the heart, he had to somehow create a complex 3D scaffold in which cells could grow into a heart. To do this, he used a printer. Instead of an ink cartridge, this printer has a cell cartridge. Instead of spraying ink onto paper in a pre-set pattern, it sprays cells onto a matrix in a pre-set pattern in successive layers. After printing multiple layers, the printer has successfully “printed” the scaffold in which the organs can be grown.

    Dr. Atala has also successfully implanted the simplest of organs, the bladder. A 16-year-old girl who was born with spina bifida, which caused her bladder to malfunction, came to Dr. Atala in search of a solution. If she drank a single glass of water, her bladder would burst. Dr. Atala took some of her bladder cells and grew a new bladder for her. He later transferred the bladder into the patient, thereby solving her bladder problems.

    Although there have been many successes in Tissue Engineering, the successfully implanted body parts have largely been relatively uncomplicated cartilage, skin, and the like. Even the success with an organ was the relatively uncomplicated bladder. The future may hold bigger and better organ transplants.