Are Mscs Stem Cells?MSCs是干细胞吗？

haoxinaok

最近看了篇文献不是太懂，想请教各位：MSCs是干细胞吗？干细胞干性标准与壁龛的关系。- p( r; ~' d& r8 f& Y7 @8 l
There is continuing disagreement as to whether MSCs can be  @* X1 f  E% Q
called stem cells or perhaps adult stem cells. Unfortunately, the, ]- M. R1 g" U! n* q) M' S
term stem cell has been embedded in the literature with varying
  G+ W% z1 `% V2 o6 V( T6 @- idegrees of rigor. A newly fertilized egg is the cleanest example of" s2 B. m6 h) s- n* p0 C
a stem cell that meets the classical criteria: it can divide asymmetrically,' r. q% [2 X" H& t* K" M
and differentiate into all cellular phenotypes. But, as1 H  ~4 {9 H7 ]8 v) P% t* u: \
has been repeatedly pointed out, we quickly move down a slippery* K5 f9 F$ P9 B; `' k
slope in using the term for similar cells. Embryonic stem
" Q: A8 y- Q+ b8 fcells require a slight loosening of the definition, as they rarely differentiate
  f" I& F7 h- a5 C8 p. s" P+ minto the trophoblasts of the placenta.18 Hematopoietic- j- o6 s$ G8 t$ U; u/ i5 D& X( q
stem cells, epithelial stem cells, and neural stem cells further
, W3 u  L9 X2 [% F1 q  Ostretch the definition, because, with a few dissenting opinions,6 K4 _5 m. Q6 _
they are generally believed to differentiate only into restricted
& Y, J0 ~5 i# ^0 M7 V2 ~* jlineages. MSCs obviously require a similar loosening of the definition% r% d2 @( r& s5 H! U3 _7 Y
of stem cells, as the term is applied to the large family of+ Z2 m, G/ X: T( W, a! w  s# S
nonhematopoietic stem-like cells that have been isolated from2 M- o5 g9 N/ [: s
most mesenchymal tissues such as bone marrow, fat, and blood3 |/ \+ s) o, ?  o- `
vessels. The debate on whether MSCs can be called stem cells in2 w& R( y- ^5 U( j# w) R+ N
part revolves around the question of whether they can be differentiated
* s0 z# z4 J4 R+ x* Binto nonmesenchymal cells. Some of the earlier observations- G7 y: d& y7 B! I* u# s
on differentiation of the cells were probably flawed because
. `; G+ t& e6 Oof technical limitations such as unreliable labels for the cells and8 `) v& y$ v4 i( b3 ?* b
inadequate experience with potential artifacts.19 But, numerous" R* R6 p! y4 J) q
investigators are continuing to report that MSCs or related cells, d; [1 n$ z$ R1 y2 T' x
from bone marrow and other tissues can be differentiated into
6 d: _9 T* V6 x- O' ]epithelial, endothelial, and neural cells.5,20–23 At the same time, the
8 Q4 g" G8 |3 N* E0 h7 \0 u+ L; Bdefinition of a stem cell is further confused with the recognition
# _  H( ]. I( K; ^6 Qthat the properties of a stem cell depend as much on the niche, R+ @4 V" Y' g
in which it resides as on the inherent “stemness” of the cell. As: _- ~" Z; i. Y7 ^7 |/ F3 Z
concluded in a recent review on hematopoietic stem cells,24 the
1 E* m% @! c* z' W/ bconcept that stem cells differentiate in a hierarchical manner dictated' M, b# z" F- R0 s7 I+ o
by the inherent properties of the cell is a “seductive … oversimplification….”
; n7 z8 }, B5 u' d8 IIt ignores the dynamic interaction between
6 K6 r3 h  J9 S1 h# r! Ncellular niches that determine the fates of stem cells. In effect, the
4 J9 d2 ^4 A9 \6 O# Y0 t5 N3 Demphasis on hierarchical differentiation of hematopoietic stem
! J6 j+ y, Z2 r. A; d+ N" s; Ocells overlooked the critical role of niches that was clearly demonstrated
; A' R2 C5 h1 t- T8 q6 w# Zby earlier studies in simpler systems, such as oogenesis6 w3 I2 u1 x! A' u$ m
and spermatogenesis! N' L1 [, {7 v
in Drosophila.Of course, the definition of a stem cell is blurred still further
6 {! D5 X) z, i) q8 Nby nuclear transfer experiments and the more recent experiments
5 g% n# a" F" j6 \% e/ y. `2 zwith induced pluripotent stem cells in which even a transient% B; [7 [3 x* s+ a2 P; f
exposure to the appropriate transcription factors is sufficient to0 Z) ^& }; g" S1 D; J$ D
reprogram the genome to a stem-like state.26 The results suggest
! Y( o" c1 t9 C( c$ jthat differences between a stem cell and a fully differentiated4 y9 H  V7 y2 O$ Z/ `
cell are primarily a question of the ease with which external or) V4 d$ j% n: f. t5 M: e0 V: R8 l
internal signals can change the microenvironment of the nucleus) e! u7 _* p, Z2 j3 x3 p% B0 `
sufficiently3 }% L* @& ^1 y  t7 Q
to redirect the phenotype of the cell.
9 S* x  }, G, F5 N/ X1 sHow can we resolve the current confusion concerning the
7 B  O9 g% B' {7 i- z4 F: ^definition of a stem cell? Unfortunately, we cannot yet fully define! W7 t. _; _; _+ x( z" y
the state of any cell in terms of all its transcripts, its epigenetic" \; C1 b; ?2 X' `; p
status, and especially its proteomics (see recent review in ref. 27).
  p; S) v# [( ?) OAlso, a static picture in time of a cell is probably not sufficient.$ i# Y0 x# T, h
The essence of a stem cell is not its status at a given point in time.
" k: k) Q( J5 {It is the potential for change in an almost Aristotelian sense.
# K: S5 U5 w; L' j4 `0 `1 TUnfortunately, again, we do not have the means of defining the# ]/ I: i) D/ N: o& o8 N
potential of a cell in a quantitative manner. The only practical( x0 P. h- W9 F  W. ?0 L& D
solution to the current confusion is apparently in trying to convey- p4 J+ p3 Y8 D" Q  _) r
the context of each type of cell with qualifiers such as hematopoietic
# X7 W' k. O& h/ l) G0 G$ z  a. rstem cells or adult stem/progenitor cells.

xjya

一般都把MSCs 归类于adult stem cells." i( ~8 M4 L8 x$ F6 R" C  @/ C, ^+ v
我在PubMed和google上没有收到楼主提到的文章，建议楼主把这篇文章的详细信息贴上来.若是一般般的杂志，也就别太在意了。

张也行

同意楼上的说法，仅仅从概念上区分各种干细胞似乎价值不大。不管是不是严格意义上的干细胞，在临床上能应用，造福大众才是重点。

xjya

同意楼上的说法。$ r  Z  I2 ~8 r: t6 Q
MSCs是adult stem cells中首种运用于细胞替代治疗心衰临床I期实验的细胞。不管是什么细胞，能治病的就是好细胞。

haoxinaok

回复 1# haoxinaok

marrowstem

允许我说点不同意见，
+ X# O5 h- e* j  WAre MSCs Stem Cells? and MSCs是干细胞吗？% j" b& q- d  b* ?* M- a" c
我觉得这是必须得到回答的原则性问题。- g  n  N* g( b6 d
      虽然MSCs目前被应用于临床替代治疗，但其实疗效并不明确，有如盲窝摸象，而原因正是对这些基础问题的机制上的不明确。  ~5 c+ O0 c# Q+ n( b: ^3 F
    虽然中国在这方面目前走在前列，干细胞的应用遍地开花，连小医院也盲目的开展，表面上看来形势一片大好，但个人认为内含“刹机”。如果再不重视研究基本机制，而只管盲目的临床应用，完全有可能最后落得一个当前中医所面临的局面。

marrowstem

也许可以思索一下，为什么通过造血干细胞移植能从治本的意义上治愈血液及免疫系统的恶性肿瘤性疾病，而为什么同样的不能通过移植MSCs来治愈恶性实体瘤呢？0 c+ S4 ~3 v1 w# D
    我想最大的可能原因就是因为对MSCs的机制上的认识不清，从而阻碍了他的进一步应用上的成功。2 ]9 Z/ {" V; w( V0 x1 u, [9 v  L
    个人认为如果没有——Are MSCs Stem Cells? and MSCs是干细胞吗？——这两个问题的明确回答，而要想得到MSCs临床应用的明确效应是不可能的。那些盲目开展细胞治疗的科室可能的结局是走不远、更扩不大。

xjya

不一样的声音才使讨论更有意义！& L" @& {& q: n: ?% w, s+ N
的确，MSCs虽然是首种运用于临床治疗心衰的细胞但是疗效的确一般般。一开始研究者们认为MSCs可以transdifferentiate为心肌细胞，神经细胞等，但是随着研究发现这种“横向分化”能力实在是有限，反而MSCs和其它类型的细胞共移植的效果更好，比如MSCs可以促进共移植的ES-CMs的存活、整合和增殖，其可能的机制是与MSCs的旁分泌作用有关。从这方面来看，深入研究MSCs的性质的确有必要。