RESUMEN
PURPOSE: Alzheimer's disease (AD) may disturb functions of the blood-brain barrier and change the disposition of drugs to the brain. This study assessed the disease-induced changes in drug transporters in the brain capillaries of transgenic AD mice. METHODS: Eighteen drug transporters and four tight junction-associated proteins were analyzed by RT-qPCR in cortex, hippocampus and cerebellum tissue samples of 12-16-month-old APdE9, Tg2576 and APP/PS1 transgenic mice and their healthy age-matched controls. In addition, microvessel fractions enriched from 1-3-month-old APdE9 mice were analyzed using RT-qPCR and Western blotting. Brain transport of methotrexate in APdE9 mice was assessed by in vivo microdialysis. RESULTS: The expression profiles of studied genes were similar in brain tissues of AD and control mice. Instead, in the microvessel fraction in APdE9 mice, >2-fold alterations were detected in the expressions of 11 genes but none at the protein level. In control mice strains, >5-fold changes between different brain regions were identified for Slc15a2, Slc22a3 and occludin. Methotrexate distribution into hippocampus of APdE9 mice was faster than in controls. CONCLUSIONS: The expression profile of mice carrying presenilin and amyloid precursor protein mutations is comparable to controls, but clear regional differences exist in the expression of drug transporters in brain.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Encéfalo/metabolismo , Inhibidores Enzimáticos/farmacocinética , Proteínas de Transporte de Membrana/metabolismo , Metotrexato/farmacocinética , Proteínas de Uniones Estrechas/metabolismo , Enfermedad de Alzheimer/genética , Animales , Transporte Biológico , Encéfalo/irrigación sanguínea , Encéfalo/efectos de los fármacos , Modelos Animales de Enfermedad , Sistemas de Liberación de Medicamentos , Descubrimiento de Drogas , Inhibidores Enzimáticos/metabolismo , Humanos , Masculino , Proteínas de Transporte de Membrana/análisis , Proteínas de Transporte de Membrana/genética , Metotrexato/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Preparaciones Farmacéuticas/metabolismo , Proteínas de Uniones Estrechas/análisis , Proteínas de Uniones Estrechas/genética , TranscriptomaRESUMEN
Conjunctiva occupies most of the ocular surface area, and conjunctival permeability affects ocular and systemic drug absorption of topical ocular medications. Therefore, the aim of this study was to obtain a computational in silico model for structure-based prediction of conjunctival drug permeability. This was done by employing cassette dosing and quantitative structure-property relationship (QSPR) approach. Permeability studies were performed ex vivo across fresh porcine conjunctiva and simultaneous dosing of a cassette mixture composed of 32 clinically relevant drug molecules with wide chemical space. The apparent permeability values were obtained using drug concentrations that were quantified with liquid chromatography tandem-mass spectrometry. The experimental data were utilized for building a QSPR model for conjunctival permeability predictions. The conjunctival permeability values presented a 17-fold range (0.63-10.74 × 10-6 cm/s). The final QSPR had a Q2 value of 0.62 and predicted the external test set with a mean fold error of 1.34. The polar surface area, hydrogen bond donor, and halogen ratio were the most relevant descriptors for defining conjunctival permeability. This work presents for the first time a predictive QSPR model of conjunctival drug permeability and a comprehensive description on conjunctival isolation from the porcine eye. The model can be used for developing new ocular drugs.
