Biomedical Engineering Reference
In-Depth Information
The most exciting use of cultured stem cells is the promise for curing many
devastating diseases like Parkinson's and other neurological illnesses. However, more
basic research remains before stem-cell-based therapy is widely used. Development
of stem cell-based therapies for neurodegenerative disorders is still at an early stage.
Many basic issues remain to be resolved, and we need to move forward with caution
and avoid scientifically ill-founded trials in affected individuals. One challenge now
is to identify molecular determinants of stem cell proliferation so as to control unde-
sired growth and genetic alterations of ESCs. We also need to know how to pattern
adult stem cells to obtain a more complete repertoire of various types of cells for
replacement, and how to induce effective functional integration of the stem cell-derived
neurons into existing neural and synaptic network. Technological advances will be
needed to make precise genetic modifications of stem cells or their progeny that will
enhance their capacity for migration, integration, and pathway reconstruction.
The potential of the brain self-repair mechanisms is virtually unexplored.
We need to develop technologies for genetic labeling of stem cell progeny so that
we can firmly establish where neurogenesis occurs and which cell types are gener-
ated following damage. The functional properties of the new neurons and their
ability to form appropriate afferent and efferent connections should be determined.
We also need to identify, with the aid of genomic and proteomic approaches, the
cellular and molecular players that, in a concerted action, regulate different steps of
neurogenesis. On the basis of this knowledge, we should design strategies to deliver
molecules that improve the yield of new functional neurons and other cells in the
damaged area.
The use of embryonic stem cells (which can evolve into any type of cell in the
body) has been surrounded by controversy. The essential importance of these findings
are in that if other scientists can duplicate the process on a larger scale, it could reduce
the need for embryonic stem cells in research and eliminate rejection problems associ-
ated with using stem cells from an outside donor. Researchers worldwide share opin-
ion that various types of stem cells hold great promise for understanding and treating
a wide variety of diseases. In a discovery that has the potential to change the face of
stem cell research, a University of Louisville scientist has identified VSELs in the
adult body that seem to behave like embryonic stem cells. Yet, of the stem cells
discussed in this review ES cells are still considered to have the most capacity to
differentiate into a variety of cells and their proliferation capacity is also unsurpassed
by any other cell type. There are three major problems with ES cells; ethical issues,
immunological rejection problems (that potentially could be solved by therapeutical
cloning), and the potential of developing teratomas.
In the future, ideally, adult (somatic) stem cells from the patient will be extracted
and manipulated, and then reintroduced into the same patient to cure debilitating
diseases, including neurological. This would preclude the use of embryonic stem
cells for cell therapy, eliminate the ethical objections against stem cell research, and
also resolve immunological rejection problems. However, at present, the cell prolif-
eration and differentiation potential of embryonic stem cells due to all obstacles
mentioned above remains still more likely to produce a cure than do the adult
(somatic) cells.
