title: Cyclosporine A kinetics in brain cell cultures and its potential of crossing the blood-brain barrier.
abstract: There is an increasing need to develop improved systems for predicting the safety of xenobiotics. However, to move beyond hazard identification the available concentration of the test compounds needs to be incorporated. In this study cyclosporine A (CsA) was used as a model compound to assess the kinetic profiles in two rodent brain cell cultures after single and repeated exposures. CsA induced-cyclophilin B (Cyp-B) secretion was also determined as CsA-specific pharmacodynamic endpoint. Since CsA is a potent p-glycoprotein substrate, the ability of this compound to cross the blood-brain barrier (BBB) was also investigated using an in vitro bovine model with repeated exposures up to 14 days. Finally, CsA uptake mechanisms were studied using a parallel artificial membrane assay (PAMPA) in combination with a Caco-2 model. Kinetic results indicate a low intracellular CsA uptake, with no marked bioaccumulation or biotransformation. In addition, only low CsA amounts crossed the BBB. PAMPA and Caco-2 experiments revealed that CsA is mostly trapped to lipophilic compartments and exits the cell apically via active transport. Thus, although CsA is unlikely to enter the brain at cytotoxic concentrations, it may cause alterations in electrical activity and is likely to increase the CNS concentration of other compounds by occupying the BBBs extrusion capacity. Such an integrated testing system, incorporating BBB, brain culture models and kinetics could be applied for assessing neurotoxicity potential of compounds.
authors: Department of Toxicology, University of Wuerzburg, Wuerzburg, Germany. Electronic address: patricia.bellwon@uni-wuerzburg.de.
authors: P
authors: P
authors: Bellwon
authors: Univ Lille Nord de France, F59000 Lille, France; UArtois, BBB Laboratory, EA 2465, F62300 Lens, France.
authors: M
authors: M
authors: Culot
authors: Division of Physiology, Department of Physiology and Medical Physics, Innsbruck Medical University, Innsbruck 6020, Austria.
authors: A
authors: A
authors: Wilmes
authors: Department of Toxicology, University of Wuerzburg, Wuerzburg, Germany.
authors: T
authors: T
authors: Schmidt
authors: Department of Physiology, University of Lausanne, Lausanne, Switzerland.
authors: M G
authors: MG
authors: Zurich
authors: Department of Animal Physiology, Institute of Biological Sciences, University of Rostock, Rostock, Germany.
authors: L
authors: L
authors: Schultz
authors: Department of Toxicology, University of Wuerzburg, Wuerzburg, Germany.
authors: O
authors: O
authors: Schmal
authors: Department of Animal Physiology, Institute of Biological Sciences, University of Rostock, Rostock, Germany.
authors: A
authors: A
authors: Gramowski-Voss
authors: Department of Animal Physiology, Institute of Biological Sciences, University of Rostock, Rostock, Germany.
authors: D G
authors: DG
authors: Weiss
authors: Division of Physiology, Department of Physiology and Medical Physics, Innsbruck Medical University, Innsbruck 6020, Austria.
authors: P
authors: P
authors: Jennings
authors: ECVAM, Institute for Health & Consumer Protection, European Commission Joint Research Centre, 21020 Ispra, VA, Italy.
authors: A
authors: A
authors: Bal-Price
authors: Mechanism of Toxicity Unit, Environment and Primary Prevention Department, Istituto Superiore di Sanità, Rome, Italy.
authors: E
authors: E
authors: Testai
authors: Department of Toxicology, University of Wuerzburg, Wuerzburg, Germany.
authors: W
authors: W
authors: Dekant
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000502:physiology; D001921:Brain / Q000166:cytology*; D018938:Caco-2 Cells; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D016572:Cyclosporine / Q000493:pharmacokinetics*; D004622:Embryo, Mammalian / Q000166:cytology; D006801:Humans; D051379:Mice; D009474:Neurons / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D016572:Cyclosporine
keywords: BBB model; Brain cell cultures; Cyclophilin B; Cyclosporine A uptake; Neurotoxicity; Passive diffusion