Biomedical Engineering Reference
In-Depth Information
they were injected into genetically matched mice, the implants were
rejected before teratomas could form (Apostolou and Hochedlinger,
2011). The experiment is based on the view that the capacity to form
teratomas is one of the tests of pluripotency. Yet the fact that in
tissue-matched mice not only did teratomas fail to form but the
implants were rejected straight away suggests that an immune
reaction is more likely than in non-tissue-matched mice. Compared
to other studies using hESCs, the overall outcome of the experiment
was the conclusion that iPSCs provoke an immune response more
than genetically matched embryonic stem cells (Apostolou and
Hochedlinger, 2011).
A number of questions have been raised about the reasons why
iPSCs are more immunogenic than embryonic stem cells (Apostolou
and Hochedlinger, 2011). Future research questions include identifying
the specific genes involved in triggering the immune reaction, identifying
whether different methods of deriving iPSCs might provoke different
immune reactions and understanding more about the differences in cell
development that characterize embryonic cells versus iPSCs (Apostolou
and Hochedlinger, 2011). What this finding in mice demonstrates
mostly, however, is that there remain a number of uncertainties about
the ways that iPSCs develop that need to be resolved before any
therapeutic applications in humans might be considered.
Nevertheless, despite ongoing technical questions that are yet to
be resolved, a number of iPSC lines have been created from different
types of somatic cells. The hope is that reprogramming cells from
patients with specific conditions will enable researchers to study how
the diseased cell develops
in
vitro.
This so-called 'disease-in-a-dish'
model is of continuing commercial interest for drug screening and
personalized medicine (Callaway, 2011a). The disease-in-a-dish
model, in theory, would allow better testing of drug development
and identification of potential side effects. This approach to drug
testing, combined with the capacity to create patient-specific iPSCs,
has the capacity to allow the identification of very specific forms of
drug treatment for individual patients (Callaway, 2011a).
It is envisaged that using stem cells cultivated
in vitro
to stand in
as an approximate model of the person will allow the close study of
the mechanism of disease development and yield an enormous
