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本帖最后由 qianqianlaile 于 2011-3-21 11:29 编辑 4 M' U% u. D8 B+ J& z! x
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INTRODUCTION9 W5 m" k+ f- }( E9 N4 l! L
Cell therapy has tremendous potential in regenerative medicine, yet, there are concerns in 7 ~. Z. e; k. _1 u) @5 x9 f; u; V
the utility of cell therapy due to questions regarding different cell harvest and cultivation 4 }; q# R5 [" }' }% } e8 Z# Y% l
methods (Haack-Sorensen et al., 2008; Mannello and Tonti, 2007). Bone marrow derived
8 [! f% _( V: o/ U7 zstem cells have been identified for a number of years, and there are a number of 5 N3 b0 Y7 z0 ]9 M5 `! t
ongoing clinical trials exploring the safety and efficacy of their use for a number of
; t) Z1 k2 t: ]- P9 L4 w( ~' Aclinical applications (Battiwalla and Hematti, 2009; Sadan et al., 2009; Satija et al., : v4 B" A/ w' A, f. S; x6 e
2009). There has been an increased interest in recent years in the potential of oral-9 r7 D& E+ V( ]1 J. ?0 k
derived stem cells for cell therapy, primarily because they can be derived from a readily
$ c( C/ E/ t3 k$ x2 E- Oavailable source, extracted teeth (Gronthos et al., 2000; Miura et al., 2003; Seo et al.,
1 m) i2 }$ F2 {$ d% T( n2004). These cells exhibit multipotency and regenerative capacities characteristic of # e5 e. L, b; T! L
mesenchymal stem cells (Batouli et al., 2003; Shi et al., 2005) and have the capacity to
2 P9 C& ~; B1 l& f7 r8 J( ?repair and regenerate tooth structures in vivo (Krebsbach and Robey, 2002; Mao et al., 2006). * T5 B, w2 H% _. B1 X+ d
Because oral-derived stem cells have been more recently identified, clinical
- d* y8 r/ {9 n- _' l7 `. c* Yprotocols are still being developed for their use. Regardless of the specific protocol
, I; G7 b3 n& ^! Rused, most current cell therapy approaches rely upon ex vivo cell expansion in order to & p+ N; X3 g6 l4 O7 K
produce sufficient cell numbers for transplantation. Though a wide variety of protocols b# J2 F2 \9 V7 L+ y
and culturing methods exist, one common aspect to most of them is the inclusion of
# ~. R- @' t) V, O# z0 D" Nanimal sera for cell expansion, in that it contains a rich source of nutrients and growth
2 m! p- @$ i: q8 Dfactors (Mannello and Tonti, 2007). Despite the widespread standard use of animal . i5 P2 V0 Z5 J3 N
sera for in vitro cell culture (Freshney, 2000), there are several problems which exist % y9 n$ n, j" V; M8 I2 f/ F2 ^8 O
relative to its use for clinical application. - t* t& l9 g4 `1 S1 I2 ] ?4 e3 N8 e$ W
One of the central issues regarding limitations in using animal sera for clinical cell + n3 Q1 q! x. T0 U! ]+ |
therapy protocols is that its components are highly variable and, in many cases,
4 \$ @# [2 F1 g, ^ wunknown. Though components of sera have identified, it has also been demonstrated $ V j, H& Q( s8 {2 r, y
that consistency between different lots cannot be assured (Price and Gregory, 1982). In ( C& R. [/ k+ q2 i" A) f
the context of multipotent stem cells, serum components and concentrations have
8 W: g. ]6 X. O9 l$ Rsignificant impact on cell survival and proliferative capacity, phenotype, and multipotent
( U* C: S" i% m9 X6 Tpotential (Agata et al., 2009; Sotiropoulou et al., 2006). Additionally, for clinical use, the z; M* c% h4 p7 Z
inclusion of xenogeneic serum for cell expansion carries immunological risks associated
6 P) w& b( e; u0 S0 |4 u' Iwith the immunogenicity of serum proteins and the potential of transmission of prion 4 k: b- K8 P4 \4 ?. c
diseases and zoonoses (Shahdadfar et al., 2005). These concerns have led to efforts ! ^) A B/ p- M6 W! G
aimed at incorporating FBS alternatives in cell expansion protocols, including the use of $ k- v/ ^7 E! P* j
autologous and allogeneic sera, and the proprietary manufacturing of serum-free media
3 E) i5 J9 u6 ?formulations by different companies (Nakamura et al., 2008). Even with these approaches,: b" ?( E8 u! Y5 [5 r- y2 [
there are limitations in the availability of both autologous and allogeneic + r6 e t: r: o2 |7 C, `
sera and companies do not freely disclose their proprietary “serum-free” media
5 Z3 `0 O4 z3 d& \& r/ x8 Scomponents. These factors not only prohibit clinical translation, but also limit # Q7 ~! P* W& O7 a$ b f9 G4 C
widespread use and study of more basic fundamental questions regarding specific + q/ n9 f) r! J( z2 s. ] H, E
mechanisms involved in the modulation of these media on cell function. As such, there
9 j. c/ S0 n* j( C! Eexists a need for the development of chemically-defined media which can propagate the
2 Y5 b! n9 [2 j: V4 Pcultivation of stem cells without adversely affecting cell function and phenotype
. J2 ^, c/ h" _: V$ \(Mannello and Tonti, 2007).
, |6 u- h$ |$ g! o yIn this study, we aimed to develop a serum-free media (K-M) for the expansion o
* |. L& K% k! J. \- k9 T% sdental-derived stem cells, including stem cells-derived from exfoliated deciduous (baby)5 x9 V, G: v! A, B7 I$ b( ^' F
teeth (SHEDs) and periodontal ligament stems cells (PDLSCs). Cell expansion in this 3 d8 t3 {8 _' A$ e* o: B% {$ w. N( ?
media was compared to standard FBS containing media used to culture these cells,
3 ]( X* I! A, e; Y! Vas well as three other serum-free media formulations (two of which are commercially available) 2 ]- C7 m( U6 r* {, w8 H4 S+ p8 @, K
used for culture of mesenchymal stem cells. Additionally, through . N" G$ {( h7 |0 r4 f, J8 P E
differentiation assays and microarray analyses, multipotency and differential gene
4 l% |% v; f% D( Eexpression of 84 stem cell associated genes was examined between cells cultured in K-
! x8 C1 D0 B7 I5 j S" |. [M vs. those cultured in FBS- containing media. |
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