ABSTRACT
There is a growing interest to use in vitro BBB cell assays in early safety assessment of compounds. By modifying a well-validated co-culture model of brain capillary endothelial and glial cells, developed by Dehouck et al. [Dehouck, M.P., Meresse, S., Delorme, P., Fruchart, J.C., Cecchelli, R., 1990. An easier, reproducible, and mass-production method to study the blood-brain barrier in vitro. Journal of Neurochemistry 54 (5), 1798-1801], it has been possible to develop a new in vitro BBB system suitable for high throughput screening (HTS). In addition, this new procedure substantially reduces the use of experimental animals and considerably facilitates the process of obtaining a functional in vitro BBB model. The model is ready to use after only 4 days of culture and then shows the typical expression and localization of tight junction proteins. The function of the P-glycoprotein and the transcriptional expression of other efflux transporters such as MRP 1, 4 and 5 have been demonstrated. In addition, the model produces a good in vitro/in vivo correlation for 10 compounds (R2=0.81). Furthermore, studies were undertaken within the European ACuteTox consortium with the objective to assess BBB toxicity and make risk assessments of potentially toxic compounds according to their predicted ability to reach the CNS compartment. These investigations demonstrated that the results produced in the HTS BBB model were similar to the standard co-culture model.
Subject(s)
Blood-Brain Barrier/drug effects , Drug Evaluation, Preclinical/methods , ATP Binding Cassette Transporter, Subfamily B/biosynthesis , ATP Binding Cassette Transporter, Subfamily B/genetics , Animals , Blotting, Western , Carrier Proteins/metabolism , Cattle , Cells, Cultured , Chemistry, Pharmaceutical , Data Interpretation, Statistical , Endothelial Cells/drug effects , Endothelium, Vascular/cytology , Endothelium, Vascular/drug effects , Microscopy, Fluorescence , Permeability/drug effects , Pharmaceutical Preparations/metabolism , RNA/biosynthesis , RNA/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction , Tight Junctions/drug effectsABSTRACT
PURPOSE: The objective of the current study was to determine the ability of some antiemetic compounds to cross the blood-brain barrier (BBB) and thereby to determine possible side effects of compounds for the central nervous system (CNS). METHODS: We compared the brain penetration of some antiemetic compounds using an in vitro BBB model consisting in brain capillary endothelial cells co-cultured with primary rat glial cells. RESULTS: This study clearly demonstrated that the metopimazine metabolite, metopimazine acid, has a very low brain penetration, lower than metopimazine and even less than the other antiemetic compounds tested in this study. CONCLUSIONS: The poor brain penetration of metopimazine acid, metopimazine biodisponible form, seems very likely related to the clinically observed difference in therapeutic and safety profile.
Subject(s)
Antiemetics/pharmacokinetics , Blood-Brain Barrier/metabolism , Chlorpromazine/pharmacokinetics , Domperidone/pharmacokinetics , Isonipecotic Acids/pharmacokinetics , Metoclopramide/pharmacokinetics , Animals , Animals, Newborn , Antiemetics/metabolism , Brain/cytology , Brain/metabolism , Capillary Permeability , Cells, Cultured , Chlorpromazine/metabolism , Claudin-1 , Coculture Techniques/methods , Domperidone/metabolism , Endothelial Cells/cytology , Endothelial Cells/metabolism , Endothelium, Vascular/metabolism , Isonipecotic Acids/metabolism , Membrane Proteins/analysis , Metoclopramide/metabolism , Neuroglia/cytology , Neuroglia/metabolism , Occludin , Phosphoproteins/analysis , Rats , Sucrose/metabolism , Tight Junctions/chemistry , Tight Junctions/metabolism , Zonula Occludens-1 ProteinABSTRACT
The treatment of ischemic strokes is limited to the prevention of cerebrovascular risk factors and to the modulation of the coagulation cascade during the acute phase. A new therapeutic strategy could be to preventively protect the brain against noxious biological reactions induced by cerebral ischemia such as oxidative stress and inflammation to minimize their neurological consequences. Here, we show that a peroxisome proliferator-activated receptor (PPAR-alpha) activator, fenofibrate, protects against cerebral injury by anti-oxidant and anti-inflammatory mechanisms. A 14 d preventive treatment with fenofibrate reduces susceptibility to stroke in apolipoprotein E-deficient mice as well as decreases cerebral infarct volume in C57BL/6 wild-type mice. The neuroprotective effect of fenofibrate is completely absent in PPAR-alpha-deficient mice, suggesting that PPAR-alpha activation is involved as a mechanism of the protection against cerebral injury. Furthermore, this neuroprotective effect appears independently of any improvement in plasma lipids or glycemia and is associated with (1) an improvement in middle cerebral artery sensitivity to endothelium-dependent relaxation unrelated to an increase in nitric oxide synthase (NOS) type III expression, (2) a decrease in cerebral oxidative stress depending on the increase in numerous antioxidant enzyme activities, and (3) the prevention of ischemia-induced expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 in cerebral vessels without any change in NOS II expression. These data demonstrate that PPAR-alpha could be a new pharmacological target to preventively reduce the deleterious neurological consequences of stroke in mice and suggest that PPAR-alpha activators could preventively decrease the severity of stroke in humans.
