[FoRK] Wake the Dead!
sdw at lig.net
Fri Jun 15 09:39:36 PDT 2012
Well, recycle them at least:
Dormancy of Stem Cells Enables Them to Remain Viable Days After Death
Featured In: Academia News | Human Studies | Europe
Thursday, June 14, 2012
Under the direction of Fabrice Chrétien, in collaboration with Shahragim Tajbakhsh, researchers from the Institut Pasteur, the
Université de Versailles Saint-Quentin-en-Yvelines, the Paris Public Hospital Network (AP-HP), and the CNRS have shown for the
first time in humans and mice, the capacity of stem cells to adopt a dormant state when their environment becomes hostile,
including several days after death. This ability to significantly reduce metabolic activity enables them to preserve their
potential for cellular division, even after extended periods post mortem. After isolation, they can then be used to repair
damaged organs or tissues. This discovery could lead to new therapeutic avenues for treating numerous diseases. The study is
being published in the journal Nature communications.
Remarkably, skeletal muscle stem cells can survive for seventeen days in humans and sixteen days in mice, post mortem well
beyond the 1-2 days currently thought. This discovery was made by researchers from the Institut Pasteur, the Université de
Versailles Saint-Quentin-en-Yvelines, the Paris Public Hospital Network (AP-HP), and the CNRS under the direction of Professor
Fabrice Chrétien*, in collaboration with a team led by Professor Shahragim Tajbakhsh**. The scientists were also able to show
that these stem cells, once back in culture, retained their capacity to differentiate into perfectly functioning muscle cells.
In light of this astonishing result, scientists then sought to characterize these cells to understand how they survive in such
adverse conditions. They observed that these cells enter a deeper state of quiescence, drastically lowering their metabolism.
This so-called "dormant" state is a result of cellular organization that is stripped to the bare minimum: fewer mitochondria
(cellular power plants using oxygen to produce energy in cells) and diminished stores of energy.
“We can compare this to pathological conditions where cells are severely deficient in resources, before regaining a normal cell
cycle for regenerating damaged tissues and organs, explains Fabrice Chrétien. When muscle is in the acute phase of a lesion, the
distribution of oxygen is highly disrupted. We have even observed that muscle stem cells in anoxia (totally deprived of oxygen)
at 4°C have a better survival rate than those regularly exposed to ambient levels of oxygen.”
The team of Fabrice Chrétien then wondered if these results were consistent with other cell types. Tests were then done on stem
cells taken from bone marrow where blood cells are produced. These cells remained viable for four days in post mortem mice
models, and more importantly, they retained their capacity to reconstitute tissue after a bone marrow transplant.
This discovery could form the basis of a new source, and more importantly new methods of conservation, for stem cells used to
treat a number of pathologies. This is the case for leukemia, for example, which requires a bone marrow transplant to restore a
patient's blood and immune cells destroyed by chemotherapy and radiation. By harvesting stem cells from the bone marrow of
consenting donors post mortem, doctors could address to a certain extent the shortage of tissues and cells. Although highly
promising, this approach in the realm of cellular therapy still requires more testing and validation before it can be used in
clinical applications. Nevertheless, it paves the way to investigate the viability of stem cells from all tissues and organs
Source: Institut Pasteur
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