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In vitro model for evaluating drug transport across the blood–brain barrier

Université d'Artois, Arras, Nord-Pas-de-Calais, France
Advanced drug delivery reviews (Impact Factor: 12.71). 05/1999; 36(2-3):165-178. DOI: 10.1016/S0169-409X(98)00083-0
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ABSTRACT The passage of substances across the blood–brain barrier (BBB) is regulated in the cerebral capillaries, which possess certain distinct different morphological and enzymatic properties compared with the capillaries of other organs. Investigations of the functional characteristics of brain capillaries have been facilitated by the use of cultured brain endothelial cells, but in most studies some characteristics of the in vivo BBB are lost. To provide an in vitro system for studying brain capillary functions, we have developed a process of coculture that closely mimics the in vivo situation by culturing brain capillary endothelial cells on one side of a filter and astrocytes on the other. In order to assess the drug transport across the blood–brain barrier, we compared the extraction ratios in vivo to the permeability of the in vitro model. The in vivo and the in vitro values showed a strong correlation. The relative ease with which such cocultures can be produced in large quantities facilitates the screening of new centrally active drugs. This model provides an easier, reproducible and mass-production method to study the blood–brain barrier in vitro.

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    • "the beginning and at the end of the experiments . The receiver compartments were sampled at the end of the experiments . The amount of radiotracer in the abluminal compartment was measured in a liquid scintillation analyser ( Packard Instrument Company , Meriden , USA ) . The BBB permeability coefficients to sucrose were calculated as described by Cecchelli et al . 1999 [ 11 ]"
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    ABSTRACT: Historically, the focus has been to use in vitro BBB models to optimize rate of drug delivery to the CNS, whereas total in vivo brain/plasma ratios have been used for optimizing extent. However, these two parameters do not necessarily show good correlations with receptor occupancy data or other pharmacological readouts. In line with the free drug hypothesis, the use of unbound brain concentrations (Cu,br) has been shown to provide the best correlations with pharmacological data. However, typically the determination of this parameter requires microdialysis, a technique not ideally suited for screening in early drug development. Alternative, and less resource-demanding methodologies to determine Cu,br employ either equilibrium dialysis of brain homogenates or incubations of brain slices in buffer to determine fraction unbound brain (fu,br), which is subsequently multiplied by the total brain concentration to yield Cu,br. To determine Cu,br/Cu,pl ratios this way, still requires both in vitro and in vivo experiments that are quite time consuming. The main objective of this study was to explore the possibility to directly generate Cu,br/Cu,pl ratios in a single in vitro model of the BBB, using a co-culture of brain capillary endothelial and glial cells in an attempt to mimick the in vivo situation, thereby greatly simplifying existing experimental procedures. Comparison to microdialysis brain concentration profiles demonstrates the possibility to estimate brain exposure over time in the BBB model. A stronger correlation was found between in vitro Cu,br/Cu,pl ratios and in vivo Cu,br/Cu,pl obtained using fu,br from brain slice than with fu,br from brain homogenate for a set of 30 drugs. Overall, Cu,br/Cu,pl ratios were successfully predicted in vitro for 88% of the 92 studied compounds. This result supports the possibility to use this methodology for identifying compounds with a desirable in vivo response in the CNS early on in the drug discovery process.
    PLoS ONE 12/2013; 8(12):e80634. DOI:10.1371/journal.pone.0080634 · 3.53 Impact Factor
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    • "The dwell time was set at 20 ms for all of the analytes. Permeability coefficients were calculated according to Equations 1–3 (Cecchelli et al., 1999): "
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    British Journal of Pharmacology 08/2012; 168(2). DOI:10.1111/j.1476-5381.2012.02145.x · 4.99 Impact Factor
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    • "We tested the effect of BK and ATP on the permeability of BCECs grown on filter membranes in the presence of glial cells (Cecchelli et al, 1999). Exposure to BK (0.5 mmol/L, present during the 60- minute duration of the permeability assay) increased the endothelial permeability measured with LY. "
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    Journal of cerebral blood flow and metabolism: official journal of the International Society of Cerebral Blood Flow and Metabolism 06/2011; 31(9):1942-57. DOI:10.1038/jcbfm.2011.86 · 5.34 Impact Factor
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