Stem Cell Effectiveness May Depend on Age

As stem cell clinical trials
for people with MS become more common, researchers are trying to understand the
biologic changes and therapeutic effects of older donor stem cells. A new study
appearing in STEM CELLS
Translational Medicine demonstrates that adipose-derived stem cells
donated by older people are less effective than cells from their younger
counterparts.


Previous studies on animals
have shown that transplantation of mesenchymal stem cells (MSCs) holds promise
as a therapy for all forms of MS. The MSCs migrate to areas of damage, release
trophic (cell growth) factors and exert neuroprotective and immunomodulatory
effects to inhibit T cell proliferation.


MS-related clinical trials
have all confirmed the safety of autologous MSC therapy. However what is
unclear is whether MSCs derived from older donors have the same therapeutic
potential as those from younger ones.


“Aging is known to have
a negative impact on the regenerative capacity of most tissues, and human MSCs
are susceptible to biologic aging including changes in differentiation
potential, proliferation ability and gene expression. These age-related
differences may affect the ability of older donor cells to migrate extensively,
provide trophic support, persist long-term and promote repair mechanisms,”
said Bruce Bunnell, Ph.D., of Tulane University’s Center for Stem Cell Research
and Regenerative Medicine. He served as lead author of the study, conducted by
a team composed of his colleagues at Tulane.


In their study, mice were
induced with chronic experimental autoimmune encephalomyelitis (EAE) and
treated before disease onset with human adipose-derived MSCs derived from
younger (less than 35 years) or older (over age 60) donors. The results
corroborated previous studies suggesting that older donors are less effective
than their younger counterparts.

“We found that, in vitro, the stem cells
from the older donors failed to ameliorate the neurodegeneration associated
with EAE. Mice treated with older donor cells had increased inflammation of the
central nervous system, demyelination leading to an impairment in movement,
cognition and other functions dependent on nerves, and a proliferation of
splenocytes [white blood cells in the spleen], compared to the mice receiving
cells from younger donors,” Dr. Bunnell noted.

Source: MS Foundation