Weill
Cornell Medical College Advance
Recovery
of Adult Bone Marrow Stem Cells for Tissue Regeneration
Edited
By Herman Rosen, M.D.
Dr. Shahin Rafii and colleagues from Weill Medical College of Cornell University
have discovered the mechanism by which organ-specific adult bone marrow stem
cells may be recruited. Stem cells derived from embryos have been the subject
of recent ethical debate, but stem cells derived from adult bone marrow may
prove to be even more suitable for therapeutic purposes, both as the key to
blood vessel formation in tumors and as an alternative source of replaceable
stem cells that can be used readily for fighting disease through organ regeneration
and gene therapy.
Stem cells derived from bone marrow normally rest there. When stimulated, they
proliferate, self-renew, and are mobilized to the peripheral blood, where they
incorporate into damaged tissue. The mechanism by which stem cells are stimulated
was published in a recent issue of Cell. The research provides enormous
promise for the development of far-reaching therapeutics. The newly unlocked
mechanism may be the key to facilitating future treatments of countless diseases,
ranging from heart disease and stroke to diabetes and Parkinson’s. By stimulating
the production of stem cells from the adult bone marrow, thereby facilitating
their recovery, doctors may eventually be able to restore the functioning of
diseased mature organs such as the heart, muscle, lung, kidneys, pancreas, and
brain.
Adult bone-marrow-derived stem cells may have an advantage over embryonic stem
cells in that they possess “the appropriate developmental instructions and are
more likely to engraft functionally into an adult tissue, undergoing regeneration
during development or after injury,” said Dr. Rafii. They found that physiological
stress, as may occur during tissue injury, activates an enzyme (called MMP-9)
in bone marrow cells, and that promotes the release of Stem Cell Factor which
leads to the proliferation and mobilization of stem cells from a dormant microenvironment
of the bone marrow to an environment that promotes their expansion, differentiation,
and mobilization to the bloodstream.
These exciting results lay the foundation for developing strategies whereby
activation of enzymes such as MMP-9 or others can function as molecular switches
to expand and recover a large population of hibernating stem cells for use in
tissue-regeneration and gene therapy.#
Dr.
Herman Rosen is Clinical Professor of Medicine at Weill Medical College of Cornell
University.
