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本帖最后由 qianqianlaile 于 2011-3-21 11:29 编辑 ' `+ e! \1 d" m w( Z0 V( M
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INTRODUCTION
' E j% ~6 B `! O7 e4 jCell therapy has tremendous potential in regenerative medicine, yet, there are concerns in
4 F; z4 z0 Q5 z5 {! Jthe utility of cell therapy due to questions regarding different cell harvest and cultivation ) g! B4 R3 `5 A! Q0 u' Z
methods (Haack-Sorensen et al., 2008; Mannello and Tonti, 2007). Bone marrow derived - o, ?, p+ Z* ~. V) M
stem cells have been identified for a number of years, and there are a number of 9 K; }" C2 x7 |+ w; Z- F
ongoing clinical trials exploring the safety and efficacy of their use for a number of 1 }+ U8 H8 V+ |/ W- Q6 M4 |
clinical applications (Battiwalla and Hematti, 2009; Sadan et al., 2009; Satija et al.,
2 ^; }: A- R" [8 |# h$ D3 H9 n2009). There has been an increased interest in recent years in the potential of oral-$ L! m: ], K5 L, H5 y' \+ i
derived stem cells for cell therapy, primarily because they can be derived from a readily 6 E& M! ^; p7 q6 I( E0 z* Q; K
available source, extracted teeth (Gronthos et al., 2000; Miura et al., 2003; Seo et al., & z- x% v- t/ L( d+ [
2004). These cells exhibit multipotency and regenerative capacities characteristic of
G, M0 y/ u: @3 _mesenchymal stem cells (Batouli et al., 2003; Shi et al., 2005) and have the capacity to 3 [( k/ x* q, F: J
repair and regenerate tooth structures in vivo (Krebsbach and Robey, 2002; Mao et al., 2006).
5 ?# B- j$ W3 N* L- e2 G- i Because oral-derived stem cells have been more recently identified, clinical ) j2 @& O% |0 o f
protocols are still being developed for their use. Regardless of the specific protocol
; b) Q6 K+ A I% G* W" q0 Xused, most current cell therapy approaches rely upon ex vivo cell expansion in order to / q6 G0 v, ~0 _- u1 z
produce sufficient cell numbers for transplantation. Though a wide variety of protocols 5 n" U1 @. B+ ]: \# m7 l' a
and culturing methods exist, one common aspect to most of them is the inclusion of
0 _; l1 `+ [; z6 f7 e |8 banimal sera for cell expansion, in that it contains a rich source of nutrients and growth
4 i- @% w# Q8 J' n* X% Zfactors (Mannello and Tonti, 2007). Despite the widespread standard use of animal / g+ J: l, {6 Q+ P- ?# x r
sera for in vitro cell culture (Freshney, 2000), there are several problems which exist
- z) z; \. N; X1 w1 {" nrelative to its use for clinical application. ( {9 Y7 W* c$ ^2 y W; R y
One of the central issues regarding limitations in using animal sera for clinical cell & F7 k# M/ i, @3 o" L1 M ^
therapy protocols is that its components are highly variable and, in many cases,
- v s' O! a* q: ^/ Xunknown. Though components of sera have identified, it has also been demonstrated
0 \, w. X+ G$ hthat consistency between different lots cannot be assured (Price and Gregory, 1982). In $ M/ f- f5 Y$ P: D4 X
the context of multipotent stem cells, serum components and concentrations have
4 n- g9 ?+ p" z r# z6 j- R! ?0 Osignificant impact on cell survival and proliferative capacity, phenotype, and multipotent
2 K# _: U) b3 G9 q e" H& a- Qpotential (Agata et al., 2009; Sotiropoulou et al., 2006). Additionally, for clinical use, the + T( Z8 L9 m+ G. S; Y% r
inclusion of xenogeneic serum for cell expansion carries immunological risks associated
6 S# f9 N$ ]$ u/ q/ ^+ S/ Bwith the immunogenicity of serum proteins and the potential of transmission of prion + C _' z! s7 }! Z
diseases and zoonoses (Shahdadfar et al., 2005). These concerns have led to efforts
9 \% {! F3 }! _3 Qaimed at incorporating FBS alternatives in cell expansion protocols, including the use of - Z' p4 t! }' `- _3 ]0 G- w. w
autologous and allogeneic sera, and the proprietary manufacturing of serum-free media
_0 Y8 a# v ]( p8 ~# w# j) F, Xformulations by different companies (Nakamura et al., 2008). Even with these approaches,5 Y$ [ ^0 ?3 F; v0 t" i
there are limitations in the availability of both autologous and allogeneic
q9 m6 k8 L9 N( y/ U1 Q( O' Ysera and companies do not freely disclose their proprietary “serum-free” media
( s% n5 h# p' f( q s8 y5 Ncomponents. These factors not only prohibit clinical translation, but also limit " Q; Z- s% b }: E R/ l: V! }
widespread use and study of more basic fundamental questions regarding specific
% I( K7 e6 \8 }5 `; Smechanisms involved in the modulation of these media on cell function. As such, there
7 e( s- p6 J. k( t: F2 {exists a need for the development of chemically-defined media which can propagate the
& m; v7 |- ^$ G- A6 Z9 V4 H) xcultivation of stem cells without adversely affecting cell function and phenotype
, b8 a1 c1 h" r$ Q(Mannello and Tonti, 2007)./ Y. {& n- b$ r) B
In this study, we aimed to develop a serum-free media (K-M) for the expansion o. {# n6 b& \7 Z" r* c& o3 x
dental-derived stem cells, including stem cells-derived from exfoliated deciduous (baby)# b$ `7 O2 D. c
teeth (SHEDs) and periodontal ligament stems cells (PDLSCs). Cell expansion in this
: U) U2 f) M, cmedia was compared to standard FBS containing media used to culture these cells,
, E s! |6 P r7 P" g5 {as well as three other serum-free media formulations (two of which are commercially available)
4 e& Z( u" k% V9 A! U1 N2 wused for culture of mesenchymal stem cells. Additionally, through ( K' Z! H- M& ?0 O6 ?( |
differentiation assays and microarray analyses, multipotency and differential gene
1 |: }' h Z. V0 ^" vexpression of 84 stem cell associated genes was examined between cells cultured in K-
+ S* j- }8 O7 aM vs. those cultured in FBS- containing media. |
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