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Abstract
As there is huge demand for liver transplantation but
there are never enough organs and the procedure is not always
successful, we can use bone marrow or umbilical cord blood
stem cells to help treat liver disease and reduce the need for
liver transplantation (Hunter D, 2003).
The discovery of adult tissue specific stem cells such as
haemopiotic stem cells, which have the ability to
transdifferentiate into other tissues, has generated much
excitement among cell biologists and transplant clinicians. It
opens new avenaes for basic biological research by using stem
cells from adults as an alternative to stem cells from embryos.
It also carries important implications for the treatment of many
liver, heart, and neurogenerative diseases (Kuehnle I and A
Goodell M, 2002).
HSCs have been reported to produce not only all of the
blood lineages, but also skeletal muscle (Gussoni E et al,
1999), neurons (Brazelton TR et al, 2000), cardiac muscle
(Orlic D et al, 2001), pulmonary epithelium (Krause DS and
Theise ND, 2001), and liver epithelium (Petersen BE et al,
1999).
These reports on stem cell plasticity and the observations
on the expression of hematopoietic markers in oval cells
described earlier led to the hypothesis that bone marrow stem
cells may give also rise to epithelial cells, including hepatic
oval cells. This was confirmed experimentally in 1999 by
Petersen and coworkers (Petersen BE et al, 1999). A murine
study showed that not only oval cells but also hepatocytes
could be derived from donor bone marrow (Thomas ED et al,
1975).
Although most published information on adult stem cells
draws heavily from studies with animal models, there is
increasing clinical evidence to support the concept of stem cells
transdifferentiation (Theise et al, 2000).
Recent findings indicate that adult BM also contains cells
that can differentiate into additional mature, nonhematopoietic
cells of multiple tissues including epithelial cells of the liver,
kidney, lung, skin, gastrointestinal (GI) tract, and myocytes of
heart and skeletal muscle (Erica L et al, 2003).
The new discovery that stem cells can also turn into liver
cells inside patients means that marrow stem cells could
eventually be used to repair damaged livers as well (White D,
2000).
Thus, presence of such hepatocyte progenitor cells in BM
could explain that in vivo differentiation of bone marrow into
hepatocytes noted in recent studies ((Lagasse E et al, 2000).
To ensure that the human stem cells developed into liverlike
cells, the researchers tested for the presence of a human
protein, albumin that is only produced by the liver (Hunter D,
2003).