What is Tissue Engineering?
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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 |
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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