Article

Back pain associated with symptomatic disc degeneration is a common
clinical condition. Intervertebral disc (IVD) cell apoptosis and senescence
increase with aging and degeneration. Repopulating the IVD with cells that could
produce and maintain extracellular matrix would be an alternative therapy to
surgery. The objective of this study was to determine the potential of human
umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) as a novel cell
source for disc repair. In this study, we intended to confirm the potential for
hUCB-MSCs to differentiate and display a chondrocyte-like phenotype after
culturing in micromass and after injection into the rabbit IVD explant culture.
We also wanted to confirm hUCB-MSC survival after transplantation into the IVD
explant culture. DESIGN: This study consisted of micromass cultures and in vitro
rabbit IVD explant cultures to assess hUCB-MSC survival and differentiation to
display chondrocyte-like phenotype. First, hUCB-MSCs were cultured in micromass
and stained with Alcian blue dye. Second, to confirm cell survival, hUCB-MSCs
were labeled with an infrared dye and a fluorescent dye before injection into
whole rabbit IVD explants (host). IVD explants were then cultured for 4 wks. Cell
survival was confirmed by two independent techniques: an imaging system detecting
the infrared dye at the organ level and fluorescence microscopy detecting
fluorescent dye at the cellular level. Cell viability was assessed by staining
the explant with CellTracker green, a membrane-permeant tracer specific for live
cells. Human type II collagen gene expression (from the graft) was assessed by
polymerase chain reaction. RESULTS: We have shown that hUCB-MSCs cultured in
micromass are stained blue with Alcian blue dye, which suggests that
proteoglycan-rich extracellular matrix is produced. In the cultured rabbit IVD
explants, hUCB-MSCs survived for at least 4 wks and expressed the human type II
collagen gene, suggesting that the injected hUCB-MSCs are differentiating into a
chondrocyte-like lineage. CONCLUSIONS: This study demonstrates the abiity of
hUBC-MSCs to survive and assume a chondrocyte-like phenotype when injected into
the rabbit IVD. These data support the potential for hUBC-MSCs as a cell source
for disc repair. Further measures of the host response to the injection and
studies in animal models are needed before trials in humans.

Langue : ANGLAIS