What is Tissue Engineering?

Tissue Engineering is the study of the growth of new connective tissues, or organs, from cells and a collagenous scaffold to produce a fully functional organ for implantation back into the donor host. This technique will allow organs to be grown from implantation (rather than transplantation) and hence free from imunological rejection. The starting point for any tissue-engineered organ is the harvesting of small amounts of tissue from the future recipient of the Tissue Engineered organ. This could be as small as a 2mm punch biopsy for some applications.

Cells from the biopsy are then cultured from explants or a collagenase digestion to create a "cell bank". These cells are then further cultured on collagenous substrates, under the correct physiological conditions, to form Tissue Engineered constructs for implantation. The process is carried out in a Tissue Culture facility to maintain a sterile environment. Cellular biochemical and physical activity can be enhanced by the addition of growth factors or cytokines, also by the use of physical stimulation. The tensioning-Culture Force Monitor applies minute physical loads to stimulate the resident cell population in the collagenous scaffold into bio-chemical and bio-physical activity normally associated with organogenesis and tissue repair. After further tissue culture under the correct conditions, the resident cells in the Tissue Engineered construct will disolve the original collagen scaffold and secrete a new collagen rich neo-tissue, the construct can then be implanted back into the patient from whom the cells were originally removed. This science will remove the necessity for anti-rejection drugs as the living tissue engineered construct has been grown from the patients own cells, and will be accepted as a natural part of the patients body.1

 

 

Neo-tissue sample created in laboratoty

 

 

Human aortic heart valve

More about Tissue Engineering

Start with some building material (e.g., extracellular matrix, biodegradable polymer), shape it as needed, seed it with living cells and bathe it with growth factors. When the cells multiply, they fill up the scaffold and grow into three-dimensional tissue, and once implanted in the body, the cells recreate their intended tissue functions. Blood vessels attach themselves to the new tissue, the scaffold dissolves, and the newly-grown tissue eventually blends in with its surroundings.

Tissue engineering frequently involves stem cells, a kind of premature cell first isolated from the body in 1992; implanting stem cells in the appropriate location can generate everything from bone to tendon to cartilage.

Cartilage Repair. Approximately 900,000 cases of traumatic injury to articular cartilage occur annually. Adult cartilage does not normally regenerate after injury leading to complications from sports and other physical injuries.

Bone Repair. An estimated 800,000 patients in the U.S. alone are hospitalized annually with severe bone fractures, of which half require open fracture reduction procedures. A considerable portion of these fractures do not heal properly requiring supplemental procedures, such as bone grafts, and other fractures are non-responsive to any effort.

Dermal Wound Healing. The failure of dermal wounds to heal properly affects an estimated 2.6 million patients in the U.S. These wounds frequently are the result of complications of other conditions such as diabetes, circulation disorders and immobilization. These wounds fail frequently to heal for an extended period of time, even several months or years, leading to serious and life threatening complications such as infections, with some requiring amputation of the afflicted extremity.2

 

References:

1.      Taken from http://www.wmin.ac.uk/cter/whatis.htm

2.      Taken from http://www.fibrogen.com/tissue/index.html

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