title: Blood-brain barrier P450 enzymes and multidrug transporters in drug resistance: a synergistic role in neurological diseases.
abstract: Drug penetration into the central nervous system (CNS) is controlled by the blood-brain barrier (BBB). Even though a number of strategies to circumvent the BBB and to improve drug access have been developed, drug resistance in CNS diseases remains an unmet clinical problem. We here review the mechanisms by which a healthy or pathological BBB influences drug distribution in the brain, with emphasis on the role of P450 metabolic enzymes and multi-drug transporter (MDT) proteins. In addition to the classic hepatic and gut biotransformation pathways, CNS expression of P450 enzymes may bear pharmacokinetic and pharmacodynamic significance exerting a metabolic activity and transforming parent drugs into specific products. We propose these mechanisms to play a major role in CNS drug resistant pathologies including refractory forms of epilepsy.  Changes in the cerebrovascular hemodynamic conditions can affect expression of P450 enzymes and MDT proteins. This should be taken into account when developing in vitro experimental approaches to reproduce the physiological or pathological properties of the BBB. Finally, a link between P450 and MDT expression in the diseased brain and cell survival is discussed.
authors.affiliation: Molecular Medicine Cerebrovascular Research Cleveland Clinic Foundation NB-20 9500 Euclid Ave Cleveland, OH 44195, USA.
authors.forename: Chaitali
authors.initials: C
authors.lastname: Ghosh
authors.forename: Vikram
authors.initials: V
authors.lastname: Puvenna
authors.forename: Jorge
authors.initials: J
authors.lastname: Gonzalez-Martinez
authors.forename: Damir
authors.initials: D
authors.lastname: Janigro
authors.forename: Nicola
authors.initials: N
authors.lastname: Marchi
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism*; D001921:Brain / Q000378:metabolism / Q000503:physiopathology; D002470:Cell Survival; D002491:Central Nervous System Agents / Q000493:pharmacokinetics / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D004351:Drug Resistance; D005786:Gene Expression Regulation; D006439:Hemodynamics; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009422:Nervous System Diseases / Q000188:drug therapy / Q000503:physiopathology
chemical_list: D002491:Central Nervous System Agents; D026901:Membrane Transport Proteins; D003577:Cytochrome P-450 Enzyme System