几年前，Duke University的科学家从脂肪组织中分离了一种基质细胞（stromal cells），具有重新编程分化的能力，能够分化成脂肪细胞、软骨细胞和骨细胞。因为这些类型的细胞都是间叶（mesenchymal tissue）或结缔组织（connective tissue）起源，所以称其为干细胞还为时尚早。而几乎整整两年以前，进一步的研究证明它们还可以分化为完全不同起源的神经细胞。而最近的研究有再更进一步。
最新的一期《Experimental Neurology》发表了研究者的文章：有这种细胞分化成的神经元细胞（neuron）和神经胶质（glial cell）细胞具有功能性，进而大大加强了这种细胞是成年干细胞的可能性。这类脂肪来源的成年基质细胞（adipose-derived adult stromal，ADAS cell），在特异性的的诱导混合试剂下，表现出神经元的形态特征，并且能够表达各种神经元细胞和神经胶质细胞的标记蛋白。
最重要的实验来自于glutamate agonist N-methyl-
Experimental Neurology Volume 187, Issue 2 , June 2004, Pages 319-328
Characterization of neuronal/glial differentiation of murine adipose-derived adult stromal cells
Neural tissue has limited capacity for intrinsic repair after injury, and the identification of alternate sources of neuronal stem cells has broad clinical potential. Preliminary studies have demonstrated that adipose-derived adult stromal (ADAS) cells are capable of differentiating into mesenchymal and non-mesenchymal cells in vitro, including cells with select characteristics of neuronal/glial tissue. In this study, we extended these observations to test the hypothesis that murine (mu) ADAS cells can be induced to exhibit characteristics of neuronal and glial tissue by exposure to a cocktail of induction agents. We characterized the differentiation of muADAS cells in vitro using immunohistochemistry and immunoblotting, and examined whether these cells respond to the glutamate agonist N-methyl--aspartate (NMDA). We found that induced muADAS cells express proteins indicative of neuronal/glial cells, including nestin, GFAP, S-100, NeuN, MAP2, tau, and
-III tubulin. Induced muADAS cells express 
-aminobutyric acid (GABA), the NR-1 and NR-2 subunits of the glutamate receptor, GAP-43, synapsin I, and voltage-gated calcium channels. Finally, induced muADAS cells demonstrate decreased viability in response to NMDA. These findings suggest that muADAS cells can be induced to exhibit several phenotypic, morphologic, and excitotoxic characteristics consistent with developing neuronal and glial tissue.
Author Keywords: Adipose-derived adult stromal cell; Mesenchymal stem cell; Neural differentiation
Fig. 1. Morphologic changes following neuronal induction of muADAS cells. (Left) MuADAS cells grown under control conditions grow as a monolayer of large, flat cells. (Right) MuADAS cells after 24 h culture in neuronal induction media display cytoplasmic retraction and a spherical cell body appearance (200× magnification).
Fig. 4. Immunocytochemistry of muADAS cells stained with antibodies against GAP-43, synapsin I, GABA, NMDA receptor subunits 1 (NR-1) and 2 (NR-2), and pan 
-1 subunit of voltage-gated calcium channels. (A) MuADAS cells grown under control conditions expressed low levels of pan -1 calcium channel marker and synapsin I, and undetectable levels of the other following markers, representative image shown. (B) GAP-43 expression after neuronal induction. (C) Synapsin I staining in muADAS cells after neuronal induction. (D) NR-1 expression seen in muADAS cells following neuronal induction. (E) NR-2 expression seen in muADAS cells following neuronal induction. (F) GABA staining seen in muADAS cells after neuronal induction. (G) Pan -1 calcium channel marker staining seen in muADAS cells following neuronal induction. Diamino benzidine (DAB) served as a brown chromagen for all markers.
