Induced pluripotent stem
cells (iPS cells) are derived typically from fully differentiated cells
that have been genetically altered, or reprogrammed, to possess the
same properties and behaviour as embryonic cells, giving them the
ability to differentiate into any of the 220 different cell types in
the body, and can be cultured to reproduce indefinitely. For
research purposes, iPS cells are preferred because they do not require
embryos as starting points, and can be used to generate cells from many
adult tissues, including skin cells.
Another advantage of using
iPS cells is that they allow for cell lines to be genetically
customized to patients, reducing the issue of immune rejection that is
common during tissue transplantation therapies.
Lunenfeld researchers have
switched virtually all human embryonic stem cell work to iPS stem
cell-derived cells, which are typically made from skin fibroblasts. Of
note, any research using human embryonic stem cell lines is conducted
under strict ethical guidance.
Listen to Dr. Andras Nagy
describe the use of iPS cells.
What researchers at the
Samuel Lunenfeld Research Institute of Mount Sinai Hospital are
contributing to this growing field:
The first two human
embryonic stem cell lines in Canada were established by Dr. Andras Nagy
following strict ethical review procedures. These have been approved by
the Canadian Institutes of Health Research (CIHR) for use by other
scientists and have enabled new insights into stem cell biology and
Dr. Nagy also devised a process for creating stem cells
without the use of a viral vector. This new method eliminates the
chance of inherited or de novo DNA mutations where there would either
be an excess or deletion of DNA segments. His team is also currently
exploring each phase of the programming process, to help make future
stem-cell based applications safer and more efficient.
Dr. Ian Rogers
is on the forefront of creating stem-cell based treatments for diabetes
and peripheral vascular disease. He and his colleagues are using stem
cells to create natural replacements for essential cells in the
pancreas that are destroyed by the illness, specifically in type 1
Dr. Rita Kandel and her team are developing biologic
replacements for damaged joints and tissues, using stem cells from the
patient’s own tissues.