WHAT IS A STEM CELL?
Stem cells may originate
from the embryo or in adult form can be found in umbilical cord blood,
adipose (fat tissue), blood and niches in organs. Stem cells have the
ability for self renewal and replication. They also are capable of forming
any type of tissue or organ in the body.
Embryonic stem cells originate
from the inner mass blastocyst. They are pluripotent and capable of
forming any organ in the body.
Adult stem cells from the
blood, bone marrow, brain, eye, muscle, gastrointestinal tract, pancreas,
liver, skin form progenitor cells that can differentiate and form specific
tissues.
Adult stem cells from one
organ are capable of forming tissue from another organ , a condition
which is called plasticity. Adult stem cells derived from adipose tissue
or umbilical cord blood have the capacity to form many types of differentiated
cells such as neuron stem cells, pancreatic stem cells, cardiomyocytes,
blood and bone cells.
Research done in animal
models and clinical trials on humans show that stem cells are capable
in differentiating into specific tissue such as heart muscle, pancreatic
islets that produce insulin, neurons that would be capable of transplantation
into patients that have damaged organs.
Adult stem cells are capable
of being transferred into any one single organ of the body. Stem cells
from the bone marrow form hematopoietic cells which produce blood ,immunological
cells, neurons, oligodendrocytes, astrocytes (brain cells), liver and
stromal cells that form heart, skeletal muscle fat, cartilage and bone.
Umbilical cord blood is
also a source of stem cells capable of differentiating into many different
organ tissues.
Isolating adult stem cells
from the bone marrow and umbilical cord blood require special laboratory
techniques to isolate them and expand their numbers in culture. Various
agents are used to take the stem cells and differentiate them into specialized
tissues.
The methods of isolating
these stem cells; differentiating them and then using transplantation
methods into the blood stream or directly into the damaged organs is
an ever growing field of research.