Partner und Internationale Organisationen
(Englisch)
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INSERM, Créteil (F), Cardiff University, Cardiff (UK), CANTAB Pharmaceuticals, Cambridge (UK),CEA-CNRS, Orsay (F), Wallenberg Neuroscience Center, Lund (S), Neurosearch, Glostrup (DK)
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Abstract
(Englisch)
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CONTINUOUS DELIVERY OF NEUROTROPHIC FACTORS TO THE CNS: COMPARISON OF POLYMER RODS, ENCAPSULATED CELLS AND LENTIVIRAL VECTORS
Jean-Charles Bensadoun, Luis Pereira de Almeida, Eric G. Fine, Anne O. Zurn, Nicole Oeglon and Patrick Aebischer
The CNS application of neurotrophic factors for neurodegenerative diseases requires methods allowing the continuous localized delivery of these molecules. In the present study, the striatal diffusion of human glial cell line-derived neurotrophic factor (hGONF), a promising candidate for the treatment of Parkinson's disease, was evaluated using three distinct delivery methods: ethylene vinyl acetate-based polymer rods, genetically modified encapsulated cells, and lentiviral vectors.
Immunohistochemical detection of hGONF to characterize the diffusion of the neurotrophic factor throughout the striatum was evaluated 1 and 4 weeks following implantation in rat striatum. GONF-releasing polymer rods, encapsulated C2C12 cells genetically engineered to release GONF, and a lentiviral vector encoding GONF were obtained as described previously (Aebischer et al., J. Neurosci. Res. 23: 282, 1989; Oeglon et al., Hum. Gene Ther. 7: 2135, 1996; Oeglon et al., Hum. Gene Ther. 11 : 179, 2000). One week post-implantation, GONF immunostaining was present over approximately 4 mm in the three groups, covering almost the entire striatum (Fig. 1A- C). The staining pattern was restricted to the striatum as delineated by the corpus callosum. Four weeks post-implantation, GONF staining was detected over approximately 2, 3, and 4 mm in the presence of polymer rods, encapsulated cells, and the lentiviral vector, respectively (Fig. 1O-F).
In order to quantify and compare the diffusion pattern of GONF in the striatum using the three delivery methods, optical density of GONF immunostaining was measured throughout the entire striatum using an image analysis program. One week post- surgery, optical densities of GONF staining obtained with rods (O.O.= 11.9 :t 2.8), capsules (O.O.= 11.8 :t 1.3), and the lentiviral vector (O.O.= 9.6 :t 1.0), were not statistically different. In contrast, at the 4 week time point, the optical densities observed with polymer rods (O.O.= 1 :t 0.4), encapsulated cells (O.O.= 4.7 :t 0.6), and the lentiviral vector (O.O.= 20.7 :t 1.7), were statistically significant (Fig. 2). In separate experiments, GONF release evaluated using an ELISA assay was of 8 :t 3.4, 24.8 :t 9.6, and 8 :t 1.7ng GONF/capsule/24h before implantation, and 1 and 3 months after explantation, respectively.
A study is ongoing in collaboration with P. Brundin and A. Bjorklund, Lund, in which encapsulated C2C12 cells genetically engineered to release GONF have been co- implanted simultaneously with human mesencephalic tissue in a rat model of Parkinson's disease to evaluate effects on graft survival and functional recovery. In addition, the same cells have been implanted in pig striatum in collaboration with L. Wahlberg, NsGene, to assess cell survival and GONF release at 1 and 6 months after implantation. Analysis of the results is in progress.
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