Article

Cultures of rat olfactory ensheathing cells are contaminated with Schwann cells.

Department of Anatomy and Cell Biology, Queen's University, Kingston, Ontario, Canada.
Neuroreport (Impact Factor: 1.64). 05/2006; 17(5):459-62. DOI: 10.1097/01.wnr.0000209000.32857.1b
Source: PubMed

ABSTRACT Implantation of cultured olfactory ensheathing cells into the damaged spinal cord of adult rats has been reported to remyelinate central axons. This observation is curious because olfactory ensheathing cells do not myelinate axons in their native environment. We have recently determined that calponin is the first definitive phenotypic marker for olfactory ensheathing cells. Primary cultures of adult rat olfactory mucosa and olfactory bulb were immunostained for p75 neurotrophin receptor and calponin. Our results reveal that two populations of p75 neurotrophin receptor-positive cells exist in primary cultures of the olfactory mucosa and bulb: calponin-positive olfactory ensheathing cells and calponin-negative Schwann cells. As olfactory tissues likely yield a mixed glial population, the idea that olfactory ensheathing cells are capable of de novo myelin synthesis after intraspinal implantation should be re-evaluated.

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    • "This medium is selective for OECs because it does not support long-term culture of Schwann cells beyond 24 hrs (Cheng et al., 1998, Levi et al., 1994, Lobsiger et al., 2000). In many laboratories the culture medium contains either fetal calf serum or one of the neuregulins which will support both OECs and Schwann cells (Bock et al., 2007, Rizek and Kawaja, 2006). "
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    ABSTRACT: Olfactory mucosa, the sense organ of smell, is an adult tissue that is regenerated and repaired throughout life to maintain the integrity of the sense of smell. When the sensory neurons of the olfactory epithelium die they are replaced by proliferation of stem cells and their axons grow from the nose to brain assisted by olfactory ensheathing cells located in the lamina propria beneath the sensory epithelium. When transplanted into the site of traumatic spinal cord injury in rat, olfactory lamina propria or purified olfactory ensheathing cells promote behavioural recovery and assist regrowth of some nerves in the spinal cord. A Phase I clinical trial demonstrated that autologous olfactory ensheathing cell transplantation is safe, with no adverse outcomes recorded for three years following transplantation. Autologous olfactory mucosa transplantation is also being investigated in traumatic spinal cord injury although this whole tissue contains many cells in addition to olfactory ensheathing cells, including stem cells. If olfactory ensheathing cells are proven therapeutic for human spinal cord injury there are several important practical issues that will need to be solved before they reach general clinical application. This article is part of a Special Issue entitled: Understanding olfactory ensheathing glia and their prospect for nervous system repair.
    Experimental Neurology 05/2011; 229(1):174-80. DOI:10.1016/j.expneurol.2010.08.025 · 4.62 Impact Factor
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    • "It has been argued that OECs are not the myelinating cell in the above studies and that contaminating SCs may be responsible for the remyelination (Rizek and Kawaja, 2006). These investigators suggest that OECs, but not SCs, express the muscle fiber actin binding protein calponin (Boyd et al., 2006), and that most cells in OEC culture preparations are p75 + and calponin -, thus suggesting a contamination in OEC cultures of Schwann cells. "
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    ABSTRACT: Olfactory ensheathing cells (OECs) are specialized glial cells that guide olfactory receptor axons from the nasal mucosa into the brain where they make synaptic contacts in the olfactory bulb. While a number of studies have demonstrated that in vivo transplantation of OECs into injured spinal cord results in improved functional outcome, precise cellular mechanisms underlying this improvement are not fully understood. Current thinking is that OECs can encourage axonal regeneration, provide trophic support for injured neurons and for angiogenesis, and remyelinate axons. However, Schwann cell (SC) transplantation also results in significant functional improvement in animal models of spinal cord injury. In culture SCs and OECs share a number of phenotypic properties such as expression of the low affinity NGF receptor (p75). An important area of research has been to distinguish potential differences in the in vivo behavior of OECs and SCs to determine if one cell type may offer greater advantage as a cellular therapeutic candidate. In this review we focus on several unique features of OECs when they are transplanted into the spinal cord.
    Neuroscience Letters 07/2009; 456(3):137-42. DOI:10.1016/j.neulet.2008.08.093 · 2.06 Impact Factor
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    • "Recently, we have used FACS to isolate OECs from the olfactory mucosa or olfactory bulbs of adult rats (Rizek and Kawaja, 2006; Jahed et al., 2007) (Fig. 7). These tissues were first dissociated by mechanical and enzymatic methods (using the procedures described by Bianco et al., 2004), and then incubated with a monoclonal IgG against p75NTR tagged with FITC (Alamone Labs, Israel). "
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    ABSTRACT: Over the past few years, the idea of using intraspinal implantations of olfactory ensheathing cells (OECs) as a therapeutic strategy to enhance recovery after spinal cord injury has quickly moved from experimentation with laboratory mammals to surgical approaches for paralyzed humans. Despite this progression, several important issues have yet to be thoroughly addressed: for instance, which of the many methods currently being used best yields enriched populations of OECs, and how such purity can be empirically tested and validated among different mammalian species, including humans. Here we offer an authoritative review of those methods used to isolate OECs from the olfactory mucosa and/or olfactory bulbs of rats, mice, dogs, pigs, non-human primates, and humans. As well, we assess which biomarkers are currently being utilized to determine the relative proportions of OECs and contaminating cells in these glial cultures. Although there have been numerous review articles regarding OECs in vitro, our review is unique in that it offers a critical assessment of the methods currently being used to generate cultures of mammalian OECs. More specifically, we examine the issue of culture contamination by phenotypically similar Schwann cells. This review is timely because recent clinical usage of OECs has come under intense criticism for a number of reasons, including the reliable identification of cultured human OECs. We believe that once these methodological issues of isolation and characterization of OECs have been resolved, this glial population will offer paralyzed individuals a truly viable cellular strategy for intraspinal therapy.
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