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Abstract
Throughout the past decades, organ transplantation
helped victims of liver. But this procedures is accompanied
with numerous problems as the demand is far greater than the
supply, no enough organs are available for patients in need,
patients die while waiting, and also, rejection and destruction
of transplanted liver in addition to high cost of this procedure
makes it unavailable for large sector of patients. Add to this,
a lot of complications accompanied with the use of immunosuppressive
medications rendering patients susceptible to
viral, bacterial diseases as well as cancer and the extremely
heavy costs for the remainder of their lives.
So, with availability of a minimally invasive
approaches, stem cell therapy has recently reffered to be
regenerative medicine provides much promise for the
treatment of what was previously regarded as incurable
diseases.
In 1960 fiest few cases of successful of stem cell of
bone marrow origin in treatment of congential Immune
deficiency disorder and end stage leukemia were reported.
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181
Stem cells are one of most fascinating areas of biology
today. But like many expanding fields of scientific inquiry,
research on stem cells raises scientific questions as rapidly as
it generates new research on stem cells is advancing
knowledge about how an organism develops from a single
cell and how healthy cells replace damaged cells in adult
organisms. This promising area of science is also leading
scientists to investigate the possibility of cell- Based
therapies to treat disease, which is often referred to as
regenerative or reparative medicine.
Stem cells have two important characters that listing
distinguish them from other types of cells.
First, they aer unspecialiazed cells that renew
themselves for long periods through cell division.
The Second is that under certain physiologic or
experimental conditions,they can be induced to become cells
with special functions such as beating cells of heart muscles
or the insulin producing cells of the pancreas.
In this literature we focused on the sources of the stem
cells which indicated in liver diseases therapy, the power of it
to regenerate and repopulate liver tissues and how to
Summary and conclusion
182
investigate stem cell transplantation by imaging techniques
and usage of markers to identify stem cells.
Until recently the three major sources of stem cells are
bone marrow,peripheral blood and cord blood Stem cell.
Three are two types of bone marrow stem Cell whether
autologous or allogenic stem cell Transplantation.
Human embryonic and adult stem cells each have
advantages and disadvantages regading potential use for cell
based regenerative theoiries.
Of course, adult and embryonic stem cells differ in the
number and types of differentiated cells types of they can
become. Embryonic stem cells can become all Cell types of
the body because they are pluripotent.
Adult stem cells are generally limited to be
Differentiated into different cell of their tissue origin.
There are many theories of transdifferentiation Which
mean conversion of cells from one differentiate to
Hepatocytes.
Although the use of stem cells for liver directed cell
based therapeutic approaches become very attractive,
Summary and conclusion
183
however, the mechanism for regeneration of liver cells by
stem cells still controversial.
Therefore, the development of appropriate methods of
cell transplantation is mandatory in order to improve
successful repopulation and tissue engineering approaches for
liver therapy by stem cells.
To prove that transdifferentiation was occurred we
must prove that the cells acquire the new Morphologic and
functional and antigenic characters of new organs e.g.,
transdifferentiation to hepatocytes.
The new cells acquire large size and acquire new
surface antigen (AFP) and appearance of functional Product
in cell culture which was albumin.
Transdifferentiation to occur there is induction stage by
nuclear transplantation or manipulation of cell culture
condition or uptake of molecules from cellular extract or
induction of ectropic gene expression.
Applications of stem cell for treatment of liver diseases
therapies seems to be a promising approach for the treatment
of liver diseases; several issues need to be aaressed to fulfill
this promise.