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Electronic Letters to:
- Cellular:
Alessandra Santos-Silva, Richard Fairless, Margaret C. Frame, Paul Montague, George M. Smith, Andrew Toft, John S. Riddell, and Susan C. Barnett- FGF/Heparin Differentially Regulates Schwann Cell and Olfactory Ensheathing Cell Interactions with Astrocytes: A Role in Astrocytosis
J. Neurosci. 2007; 27: 7154-7167[Abstract] [Full text] [PDF]
eLetters: Submit a response to this article
Electronic letters published:
Distinct properties of OECs and Schwann cells: intrinsic or induced?
- Konstantin Wewetzer (16 July 2007)
Distinct properties of OECs and Schwann cells: intrinsic or induced? 16 July 2007 
Konstantin Wewetzer,
associate professor
Hannover Medical School; University of Veterinary Medicine, Dept. Pathol., 30559 Hannover, GermanySend letter to journal:
Re: Distinct properties of OECs and Schwann cells: intrinsic or induced?
konstantin.wewetzer{at}tiho-hannover.de Konstantin Wewetzer
The question of whether olfactory ensheathing cells (OECs) display a unique regenerative potential is still unresolved. In a series of studies including this one, Susan Barnett and co-workers reported differential behaviour of OECs and Schwann cells following confrontation with astrocytes in vitro and in vivo. However, methodological problems leave the conclusion that this reflects intrinsic cell type-specific properties in question. The major point is that comparable culture conditions were used in the confrontation assays but not during cell isolation. There are two important questions. First, are the differences in the isolation protocol of minor significance, and second, do both cell types display specific growth requirements? In our view, the answer to both questions is clearly no.
We and others have cultured both cell types under identical conditions avoiding the use of conditioned media (Wewetzer and Brandes, 2006). In this study, however, OECs were exposed to astrocyte-conditioned medium, FGF-2 (500ng/ml, Fairless et al., 2005), heregulin-ß1 (50ng/ml), and forskolin (5x10-7M) whereas Schwann cells received no astrocyte- conditioned medium, no FGF-2, only 20ng/ml heregulin-ß1 but twice as much forskolin. The authors cannot exclude the possibility that this special treatment of OECs induced long-lasting changes of their cellular phenotype biasing the subsequent confrontation and transplantation experiments. Forskolin dramatically alters gene expression (Wewetzer et al., 2001) and 500ng/ml FGF-2 is far beyond any physiological relevance. To expose OECs but not Schwann cells to conditioned medium of the cell type the interaction to which is studied subsequently in vitro and in vivo is a fundamental problem.
References
Fairless R, Frame MC, Barnett SC (2005) N-cadherin differentially determines Schwann cell and olfactory ensheathing cell adhesion and migration responses upon contact with astrocytes. Mol Cell Neurosci 28:253 -263.
Wewetzer K, Brandes G (2006) Axonal signalling and the making of olfactory ensheathing cells: a hypothesis. Neuron Glia Biol 2:217-224.
Wewetzer K, Grothe C, Claus P (2001) In vitro expression and regulation of ciliary neurotrophic factor and its alpha receptor subunit in neonatal olfactory ensheathing cells. Neurosci Lett 306:165-168
Email: konstantin.wewetzer@tiho-hannover.de
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