Biomedical Engineering Reference
In-Depth Information
the main limitations to be faced in achieving a widespread therapeutic
use of MSCs include both their scarcity in adult tissues and the current
lack of simple unambiguous identifying markers. these are major issues
contributing towards the cost effectiveness and standardisation of their use.
On the other hand, evidence suggesting wider MSC tissue distribution and
greater plasticity stimulates research in this field (Godara
et al
., 2008a).
therefore, advances in stem cell biology research are fundamental steps
to understanding fully the role of these cells in tissue regeneration and to
optimising their exploitation in a therapeutic context (Dawson and Oreffo,
2008).
in the past few years, intensive research into understanding the biological
characteristics of MSCs has already shed light on some of their phenotypic
markers, their immunosuppressive-non-immunogenic properties and their
role in the treatment of graft-versus-host disease, in the acceleration of
haematopoietic recovery and in the treatment of selected inherited diseases
(Pelagiadis
et al
., 2008).
although autologous bone marrow represents the main source of MSCs
for both experimental and clinical studies, their clinical use may be limited
by both their number and their declined differentiation potential in relatively
elderly patients. For this reason, alternative sources of MSCs have been
investigated that include adipose tissue obtained by lipoaspiration and
umbilical cord blood, the latter containing high precursor frequencies and
youngest cells. the yields when isolating these cells from each of these
tissues, as well as their expansion and differentiation potentials, have been
analysed (Bieback
et al
., 2008).
adipose tissue-derived mesenchymal stem cells (atMSCs) have been
shown to differentiate into bone, cartilage, fat or muscle. However, it is not
certain that ATMSCs are equal to bone marrow-derived mesenchymal MSCs
for their bone and cartilage forming potential. For this purpose, studies have
been performed where MSCs from adipose and bone marrow tissues have
been compared for their ability to express typical MSC markers such as
StRO-1 and CD34 and for their osteogenic potential in typical osteogenic
cell culture media (im
et al
., 2005). the results showed that both bone-
derived MSCs and atMSCs were StRO-1 positive and CD34 negative, but
osteoblastic differentiation of ATMSCs was significantly lower than in cells
derived from bone marrow, suggesting that atMSCs may have an osteogenic
potential inferior to the cells derived from bone marrow.
in a similar study, atMSCs osteogenic potential was compared to that
of cells deriving from bone marrow and periosteum (PMSCs) in
in vitro
and
in vivo
tests (Hayashi
et al
., 2008). Colony-forming unit frequency in
bone marrow-derived cells in this type of MSCs, together with the PMSCs,
showed the highest osteogenic activity both in culture and upon subcutaneous
implantation in rats by hydroxyapatite scaffolds.
