Stem Cells
The use of stem cells in biomedical research
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Stem cells
are cells in the body that can specialize into
particular types of cells. The process of specializing is known as
differentiation. Differentiation occurs when specific genes are
activated or silenced to induce cell behaviour in accordance with its
function.
Widely touted as a source of great
hope for use in regenerative medicine, stem cells are being
investigated for use in the development of new drugs to prevent and
treat illnesses including Parkinson’s disease, spinal cord injury and
peripheral vascular disease.
Adult stem cells occur naturally in different parts of the body but typically grow slowly, are rare and difficult to isolate, and can only develop into a limited range of other cell types. For research purposes, embryonic stem cells are preferred as they can be readily expanded in culture and grown indefinitely, and they also possess the unique potential to form any tissue in the body (aside from extra-embryonic tissues such as placenta). |
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. |
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Haematopoietic stem cells—those that give rise to all different blood types—are currently used for the clinical treatment of leukemia and lymphoma via autologous (cells are reintroduced into the same patient) or allogeneic (cells are donated from a different individual who is closely matched) transplant. Human embryonic stem cells are derived from the cells of an early pre-embryo less than six days old (and consisting of less than 100 cells) that has not yet implanted in the uterus wall. 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. |
Meet the Experts:
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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
diabetes.
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.
