RESUMO
Tetrahydrohyperforin (IDN-5706) is a semisynthetic derivative of hyperforin, one of the main active components of Hypericum perforatum extracts. It showed remarkable positive effects on memory and cognitive performances in wild-type mice and in a transgenic mouse model of Alzheimer's disease, but little was known about the concentrations it can reach in the brain. The investigations reported herein show that repeated treatment of mice with tetrahydrohyperforin (20 mg/kg intraperitoneally, twice daily for 4 days and once on the fifth day) results in measurable concentrations in the brain, up to 367 ng/g brain (â¼700 nM) 6 h after the last dose; these concentrations have significant effects on synaptic function in hippocampal slices. The other main finding was the identification and semiquantitative analysis of tetrahydrohyperforin metabolites. In plasma, three hydroxylated/dehydrogenated metabolites were the largest (M1-3) and were also formed in vitro on incubation of tetrahydrohyperforin with mouse liver microsomes; the fourth metabolite in abundance was a hydroxylated/deisopropylated derivative (M13), which was not predicted in vitro. These metabolites were all detected in the brain, with peak areas from 10% (M1) to â¼1.5% (M2, M3, and M13) of the parent compound. In summary, repeated treatment of mice with tetrahydrohyperforin gave brain concentrations that might well underlie its central pharmacological effects. We also provide the first metabolic profile of this compound.
Assuntos
Encéfalo/efeitos dos fármacos , Hypericum/química , Floroglucinol/análogos & derivados , Terpenos/farmacocinética , Doença de Alzheimer/tratamento farmacológico , Animais , Cromatografia Líquida de Alta Pressão , Modelos Animais de Doenças , Hipocampo/metabolismo , Camundongos , Microssomos Hepáticos , Estrutura Molecular , Floroglucinol/administração & dosagem , Floroglucinol/química , Floroglucinol/farmacocinética , Terpenos/administração & dosagem , Terpenos/químicaRESUMO
Pharmacoresistance in epileptic patients may be ascribed to at least two, not mutually exclusive, mechanisms: a pharmacokinetic mechanism and a decreased sensitivity or availability of targets to antiepileptic drugs (AEDs; i.e., carbamazepine and phenytoin (CBZ, PHT)). Brain:plasma drug concentration ratios were determined intraoperatively during lobectomies performed to alleviate drug-resistant seizures. The brain:plasma ratio of CBZ was 1.48 when therapeutic serum levels (15-34 microM) were achieved. When concentrations of CBZ found in multiple-drug-resistant brain were directly applied to human cortical slices from drug-resistant patients made hyperexcitable and hypersynchronous by Mg(2+)-free media, bursting frequency was not significantly affected and overall excitability was reduced by 40%. Similar results were obtained for PHT. At higher AED concentrations (60-200 microM), a dose-dependent decrease of bursting frequency and amplitude was observed. Slices from drug-resistant epileptic patients made hypersynchronous/hyperexcitable by elevated potassium or inhibition of GABA-A receptors behaved similarly. Of note is the response of slices from human multiple-drug-resistant brain, which was greater than in rodent cortex from naive animals. Taken together, our results support the hypothesis that multiple drug resistance to AEDs involves cerebrovascular changes that impede the achievement of appropriate drug levels in the central nervous system.
Assuntos
Anticonvulsivantes/administração & dosagem , Encéfalo/efeitos dos fármacos , Epilepsia/fisiopatologia , Adolescente , Adulto , Idoso , Animais , Anticonvulsivantes/sangue , Anticonvulsivantes/líquido cefalorraquidiano , Encéfalo/metabolismo , Criança , Pré-Escolar , Cromatografia Líquida de Alta Pressão/métodos , Resistência a Medicamentos , Epilepsia/tratamento farmacológico , Feminino , Humanos , Técnicas In Vitro , Lactente , Masculino , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Potenciais da Membrana/efeitos da radiação , Camundongos , Pessoa de Meia-Idade , Técnicas de Patch-Clamp/métodos , Cloreto de Potássio/farmacologia , RatosRESUMO
The causes and mechanisms underlying multidrug resistance (MDR) in epilepsy are still elusive and may depend on inadequate drug concentration in crucial brain areas. We studied whether limbic seizures or anticonvulsant drug treatments in rodents enhance the brain expression of the MDR gene (mdr) encoding a permeability glycoprotein (P-gp) involved in MDR to various cancer chemotherapeutic agents. We also investigated whether changes in P-gp levels affect anticonvulsant drug concentrations in the brain. Mdr mRNA measured by RT-PCR increased by 85% on average in the mouse hippocampus 3-24 hr after kainic acid-induced limbic seizures, returning to control levels by 72 hr. Treatment with therapeutic doses of phenytoin or carbamazepine for 7 d did not change mdr mRNA expression in the mouse hippocampus 1-72 hr after the last drug administration. Six hours after seizures, the brain/plasma ratio of phenytoin was reduced by 30% and its extracellular concentration estimated by microdialysis was increased by twofold compared with control mice. Knock-out mice (mdr1a/b -/-) lacking P-gp protein showed a 46% increase in phenytoin concentrations in the hippocampus 1 and 4 hr after injection compared with wild-type mice. A significant 23% increase was found in the cerebellum at 1 hr and in the cortex at 4 hr. Carbamazepine concentrations were measurable in the hippocampus at 3 hr in mdr1a/b -/- mice, whereas they were undetectable at the same time interval in wild-type mice. In rats having spontaneous seizures 3 months after electrically induced status epilepticus, mdr1 mRNA levels were enhanced by 1.8-fold and fivefold on average in the hippocampus and entorhinal cortex, respectively. Thus, changes in P-gp mRNA levels occur in limbic areas after both acute and chronic epileptic activity. P-gp alterations significantly affect antiepileptic drugs concentrations in the brain, suggesting that seizure-induced mdr mRNA expression contributes to MDR in epilepsy.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Encéfalo/fisiopatologia , Resistência a Medicamentos , Convulsões/fisiopatologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Animais , Anticonvulsivantes/farmacocinética , Anticonvulsivantes/farmacologia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Modelos Animais de Doenças , Resistência a Medicamentos/fisiologia , Estimulação Elétrica , Eletroencefalografia , Córtex Entorrinal/efeitos dos fármacos , Córtex Entorrinal/metabolismo , Expressão Gênica/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Homozigoto , Sistema Límbico/efeitos dos fármacos , Sistema Límbico/metabolismo , Sistema Límbico/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Hyperforin is one of the possible active principles mediating the antidepressant activity of Hypericum perforatum L. extracts. The ester derivative IDN 5491 (hyperforin-trimethoxybenzoate) showed antidepressant-like properties in the forced swimming test (FST) in rats, with no effect on open-field activity, when given as three intraperitoneal injections in 24 h at 3.125 and 6.25 mg/kg. The plasma concentrations of IDN 5491 were 30-50 microM, and those of hyperforin much lower but still close to those after effective doses of hyperforin-dicyclohexylammonium and Hypericum extract. This suggests that hyperforin plays a role in the antidepressant-like effect of the ester and of Hypericum extract. In vitro binding and uptake data showed that IDN 5491 is inactive on a wide panel of CNS targets at a concentration (14 microM) much higher than that measured in the brain of treated rats (0.3 microM). Like the extract, the antidepressant-like effect of IDN 5491 was blocked by (-)-sulpiride, a selective D2 receptor antagonist and by BD-1047, a selective sigma1 antagonist. Ex-vivo binding studies showed that brain sigma1 receptors are occupied after in vivo treatment with IDN 5491, possibly by an unknown metabolite or by endogenous ligand induced by hyperforin.
Assuntos
Antidepressivos/uso terapêutico , Compostos Bicíclicos com Pontes/uso terapêutico , Floroglucinol/análogos & derivados , Floroglucinol/uso terapêutico , Terpenos/uso terapêutico , Animais , Antidepressivos/metabolismo , Compostos Bicíclicos com Pontes/metabolismo , Ésteres , Hypericum , Imobilização , Masculino , Floroglucinol/metabolismo , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/metabolismo , Extratos Vegetais/uso terapêutico , Ligação Proteica/fisiologia , Ratos , Estresse Fisiológico/tratamento farmacológico , Estresse Fisiológico/metabolismo , Terpenos/metabolismoRESUMO
Juveniles (50 days post hatch) of a native cyprinid fish (Barbus plebejus) were exposed for 7 months to sediments from the River Lambro, a polluted tributary impairing the quality of the River Po for tens of kilometers from their confluence. Sediments were collected upstream of the city of Milan and downstream at the closure of the drainage basin of the River Lambro. Chemical analyses revealed the presence of a complex mixture of bioavailable endocrine-active chemicals, with higher exposure levels in the downstream section of the tributary. Mainly characterized by brominated flame retardants, alkylphenols, polychlorinated biphenyls, and minor co-occurring personal care products and natural hormones, the sediment contamination induced reproductive disorders, as well as other forms of endocrine disruption and toxicity. In particular, exposed male barbel exhibited higher biliary PAH-like metabolites, overexpression of the cyp1a gene, vitellogenin production in all specimens, the presence of oocytes (up to 22% intersex), degenerative alterations in their testis, liver fat vacuolization, a marked depression of total thyroxine (T4) and triiodothyronine (T3) plasma levels, and genotoxic damages determined as hepatic DNA adducts. These results clearly demonstrate that Lambro sediments alone are responsible for recognizable changes in the structure and function of the reproductive and, in general, the endocrine system of a native fish species. In the real environment, exposure to waterborne and food-web sources of chemicals are responsible for additional toxic loads, and the present findings thus provide evidence for a causal role of this tributary in the severe decline observed in barbel in recent decades and raise concern that the fish community of the River Po is exposed to endocrine-mediated health effects along tens of kilometres of its course.
Assuntos
Cyprinidae/fisiologia , Sistema Endócrino/efeitos dos fármacos , Exposição Ambiental , Sedimentos Geológicos/química , Gônadas/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Regulação da Expressão Gênica/efeitos dos fármacos , Itália , Fígado/efeitos dos fármacos , Masculino , Rios/química , Glândula Tireoide/efeitos dos fármacosRESUMO
RATIONALE: Hyperforin has been identified as an active constituent of Hypericum perforatum but its importance in the antidepressant effect of this plant's extracts is not really known. OBJECTIVE: To evaluate the antidepressant-like activity of two extracts in relation to the content of hyperforin and its plasma and whole brain concentrations, compared with a stable salt of hyperforin (dicyclohexylammonium; DCHA). METHODS: The effects of the extracts and hyperforin were evaluated in the rat forced swimming test. The specificity of the effects was demonstrated evaluating the rats' locomotor activity. Plasma and brain concentrations of hyperforin were determined by high performance liquid chromatography. RESULTS: The 4.5% extract (but not the 0.5% extract) given as three IP injections in 24 h (3.12-6.25 mg/kg) reduced the total immobility of rats, yielding dose-related plasma concentrations of hyperforin. These concentrations were of a similar magnitude to those after hyperforin DCHA which also significantly reduced immobility when given on the basis of the hyperforin content of the 4.5% extract (0.14 and 0.28 mg/kg). However, hyperforin was undetectable in rat brain, possibly because of poor passage of the blood-brain barrier. CONCLUSION: These results support the view that hyperforin plays a key role in the antidepressant-like activity of Hypericum p. However, brain concentrations after effective doses are probably far from those active in vitro on the neurotransmitter mechanisms so far investigated.
Assuntos
Antidepressivos/farmacologia , Hypericum , Fitoterapia , Extratos Vegetais/farmacologia , Terpenos/farmacologia , Animais , Antidepressivos/farmacocinética , Nível de Alerta/efeitos dos fármacos , Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Compostos Bicíclicos com Pontes , Cicloexilaminas/farmacologia , Relação Dose-Resposta a Droga , Comportamento Exploratório/efeitos dos fármacos , Masculino , Atividade Motora/efeitos dos fármacos , Floroglucinol/análogos & derivados , Extratos Vegetais/farmacocinética , Ratos , Ratos Endogâmicos , Relação Estrutura-Atividade , Terpenos/farmacocinéticaRESUMO
The multiple-dose pharmacokinetics and safety of a new potential antidementia compound, CL 275,838, were examined in two randomized, double-blind, parallel-group, placebo-controlled studies. The Alzheimer Disease Assessment Scale (ADAS) was employed to preliminarily assess the patients' cognitive and the behavioral profiles. In the first study, nine patients with Alzheimer type or vascular dementia were treated for 2 weeks with daily doses of 50 mg. In the second study, nine other patients, selected with the same inclusion/exclusion criteria and treated following the same experimental design, were given 100 mg day(minus sign1) CL 275,838. At the lower dose, no side effects were detected; in the 100-mg day(minus sign1) study, mild drowsiness (one patient) and moderate agitation (two patients) were observed. Laboratory tests showed no changes in either study, apart from a slight, transient increase in serum bilirubin in one patient given 100 mg. At the dose of 50 mg, no patients showed any modification on the ADAS, whereas three patients given 100 mg showed some improvement. During the 2 weeks of oral dosing, predose plasma concentrations of the parent compounds and its metabolites II and IV increased but not in proportion to the dose, although at both doses, accumulation was essentially complete within 10 days. At 50 mg, the mean steady-state C(max) and C(ss) of the parent compound were similar to those reached in young males after a comparable regimen. Mean steady-state metabolite-to-parent drug ratios were higher in patients than in healthy individuals, although there was wide variation in our patient group. Mean washout t(1/2) of the parent compound (34 h) and its metabolites II (37 h) and IV (41 h) were longer than in young men and were similar in all cases to those observed after single doses in healthy elderly subjects. After 100 mg, mean C(max) and C(ss) of the unchanged compound rose more than proportionally and the apparent t(1/2) tended to rise, compared with the lower dose. Mean steady-state oral clearance decreased, changing the metabolite-to-parent drug ratios, suggesting nonlinear kinetics after several relatively high oral doses. This might explain why the higher dose was less well tolerated.
RESUMO
BACKGROUND: The kynurenine pathway (KP) is the major route of tryptophan (TRP) catabolism and is activated by inflammation and after cardiac arrest in animals. We hypothesized that the KP activation level correlates with severity of post-cardiac arrest shock, early death, and long-term outcome. METHODS AND RESULTS: Plasma was obtained from 245 patients enrolled in a prospective multicenter observational study in 21 intensive care units in Finland. Time to return of spontaneous circulation, lowest systolic arterial pressure, and bicarbonate during the first 24 hours were collected. A cerebral performance category of 3 to 5 defined 12-month poor outcome. Plasma TRP and KP metabolites, kynurenine (KYN), kynurenic acid, 3-hydroxyanthranilic acid, and the ratio of KYN to TRP were measured by liquid chromatography and mass spectrometry. All KP metabolites at intensive care unit admission were significantly higher in cardiac arrest patients with a nonshockable rhythm compared to those with a shockable rhythm, and kynurenic acid and 3-hydroxyanthranilic acid correlated with time to return of spontaneous circulation. Patients with higher levels of KYN, KYN to TRP, kynurenic acid, and 3-hydroxyanthranilic acid had lower 24-hour systolic arterial pressure and bicarbonate. All KP metabolites and the ratio of KYN to TRP, but not TRP, were significantly higher in patients who died in the intensive care unit in comparison to those who survived. Multivariable logistic regression showed that high kynurenic acid (odds ratio: 1.004; 95% confidence interval: 1.001 to 1.008; P=0.014), and 3-hydroxyanthranilic acid (odds ratio: 1.011; 95% confidence interval: 1.001 to 1.022; P=0.03) were independently associated with 12-month poor outcome and significantly improved risk reclassification. CONCLUSIONS: KP is activated early after cardiac arrest and is associated with severity of post-cardiac arrest shock, early death, and poor long-term outcome.
Assuntos
Reanimação Cardiopulmonar , Cinurenina/sangue , Parada Cardíaca Extra-Hospitalar/mortalidade , Choque Cardiogênico/mortalidade , Ácido 3-Hidroxiantranílico/metabolismo , Idoso , Pressão Arterial/fisiologia , Cromatografia Líquida , Feminino , Humanos , Ácido Cinurênico/sangue , Modelos Logísticos , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Parada Cardíaca Extra-Hospitalar/sangue , Parada Cardíaca Extra-Hospitalar/terapia , Prognóstico , Estudos Prospectivos , Choque Cardiogênico/sangue , Choque Cardiogênico/fisiopatologia , Triptofano/sangueRESUMO
Memory loss is one of the key features of cognitive impairment in either aging, Mild Cognitive Impairment (MCI) or dementia. Pharmacological treatments for memory loss are today focused on addressing symptomatology. One of these approved compounds is memantine, a partial NMDA receptor antagonist that has proved its beneficial effects in cognition. The Octodon degus (O. degus) has been recently proposed as a potential model relevant for neurodegenerative diseases. However, there are no previous studies investigating the effect of pharmacological treatments for age-related cognitive impairment in this rodent. In this work we aimed to evaluate the effect of memantine on sleep deprivation (SD)-induced memory impairment in young and old O. degus. Young and old animals were trained in different behavioral paradigms validated for memory evaluation, and randomly assigned to a control (CTL, n=14) or an SD (n=14) condition, and treated with vehicle or memantine (10-mg/Kg i.p.) before the SD started. We demonstrate that SD impairs memory in both young and old animals, although the effect in the old group was significantly more severe (P<0.05). Memantine pretreatment was able to prevent the cognitive impairment caused by SD in both age groups, while it had no negative effect on CTL animals. The positive effect of memantine in counteracting the negative effect of SD on the retrieval process even in the aged O. degus further supports the translational potential of both the challenge and the species, and will enable a better understanding of the behavioral features of memantine effects, especially related with reference and working memories.
Assuntos
Envelhecimento/efeitos dos fármacos , Memantina/farmacologia , Transtornos da Memória/prevenção & controle , Memória de Curto Prazo/efeitos dos fármacos , Nootrópicos/farmacologia , Privação do Sono/complicações , Envelhecimento/fisiologia , Animais , Feminino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Memantina/sangue , Transtornos da Memória/etiologia , Transtornos da Memória/fisiopatologia , Memória de Curto Prazo/fisiologia , Testes Neuropsicológicos , Nootrópicos/sangue , Octodon , Distribuição Aleatória , Reconhecimento Psicológico/efeitos dos fármacos , Reconhecimento Psicológico/fisiologia , Privação do Sono/fisiopatologiaRESUMO
Oxidative stress and mitochondrial impairment are the main pathogenic mechanisms of Amyotrophic Lateral Sclerosis (ALS), a severe neurodegenerative disease still lacking of effective therapy. Recently, the coenzyme-Q (CoQ) complex, a key component of mitochondrial function and redox-state modulator, has raised interest for ALS treatment. However, while the oxidized form ubiquinone10 was ineffective in ALS patients and modestly effective in mouse models of ALS, no evidence was reported on the effect of the reduced form ubiquinol10, which has better bioavailability and antioxidant properties. In this study we compared the effects of ubiquinone10 and a new stabilized formulation of ubiquinol10 on the disease course of SOD1(G93A) transgenic mice, an experimental model of fALS. Chronic treatments (800 mg/kg/day orally) started from the onset of disease until death, to mimic the clinical trials that only include patients with definite ALS symptoms. Although the plasma levels of CoQ10 were significantly increased by both treatments (from <0.20 to 3.0-3.4 µg/mL), no effect was found on the disease progression and survival of SOD1(G93A) mice. The levels of CoQ10 in the brain and spinal cord of ubiquinone10- or ubiquinol10-treated mice were only slightly higher (≤10%) than the endogenous levels in vehicle-treated mice, indicating poor CNS availability after oral dosing and possibly explaining the lack of pharmacological effects. To further examine this issue, we measured the oxidized and reduced forms of CoQ9/10 in the plasma, brain and spinal cord of symptomatic SOD1(G93A) mice, in comparison with age-matched SOD1(WT). Levels of ubiquinol9/10, but not ubiquinone9/10, were significantly higher in the CNS, but not in plasma, of SOD1(G93A) mice, suggesting that CoQ redox system might participate in the mechanisms trying to counteract the pathology progression. Therefore, the very low increases of CoQ10 induced by oral treatments in CNS might be not sufficient to provide significant neuroprotection in SOD1(G93A) mice.
Assuntos
Esclerose Lateral Amiotrófica/metabolismo , Sistema Nervoso Central/metabolismo , Ubiquinona/análogos & derivados , Esclerose Lateral Amiotrófica/sangue , Esclerose Lateral Amiotrófica/patologia , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Sistema Nervoso Central/efeitos dos fármacos , Sistema Nervoso Central/patologia , Modelos Animais de Doenças , Progressão da Doença , Humanos , Camundongos , Camundongos Transgênicos , Medula Espinal/efeitos dos fármacos , Medula Espinal/metabolismo , Medula Espinal/patologia , Superóxido Dismutase/metabolismo , Ubiquinona/administração & dosagem , Ubiquinona/sangue , Ubiquinona/metabolismo , Ubiquinona/farmacologiaRESUMO
Abstract Doxycycline inhibits amyloid formation in vitro and its therapeutic efficacy is under evaluation in clinical trials for different protein conformational diseases, including prion diseases, Alzheimer's disease and transthyretin amyloidosis. In patients on chronic hemodialysis, a persistently high concentration of ß2-microglobulin causes a form of amyloidosis (dialysis-related amyloidosis, DRA) localized in bones and ligaments. Since doxycycline inhibits ß2-microglobulin fibrillogenesis in vitro and accumulates in bones, DRA represents an ideal form of amyloidosis where doxycycline may reach a therapeutic concentration at the site of amyloid deposition. Three patients on long-term dialysis with severe articular impairment and uncontrollable pain due to DRA were treated with 100 mg of doxycycline daily. Pharmacokinetics and safety of treatment were conducted. Plasmatic levels of the drug reached a plateau after one week (1.1-2.3 µg/ml). Treatment was well tolerated in two patients for a year, while one was suspended after 5 months due to mild esophagitis. Treatment was associated with a significant reduction in articular pain and with a significant and measurable improvement in passive and active movements in all cases, despite the persistence of unchanged amyloid deposits measured by magnetic resonance imaging.
Assuntos
Amiloidose/tratamento farmacológico , Artralgia/tratamento farmacológico , Doxiciclina/uso terapêutico , Dor Intratável/tratamento farmacológico , Placa Amiloide/patologia , Diálise Renal/efeitos adversos , Amiloidose/etiologia , Amiloidose/metabolismo , Amiloidose/patologia , Artralgia/etiologia , Artralgia/metabolismo , Artralgia/patologia , Osso e Ossos/efeitos dos fármacos , Osso e Ossos/metabolismo , Osso e Ossos/patologia , Doxiciclina/farmacocinética , Humanos , Ligamentos Articulares/efeitos dos fármacos , Ligamentos Articulares/metabolismo , Ligamentos Articulares/patologia , Masculino , Pessoa de Meia-Idade , Dor Intratável/etiologia , Dor Intratável/metabolismo , Dor Intratável/patologia , Placa Amiloide/etiologia , Placa Amiloide/metabolismo , Articulação do Ombro/efeitos dos fármacos , Articulação do Ombro/metabolismo , Articulação do Ombro/patologia , Microglobulina beta-2/antagonistas & inibidores , Microglobulina beta-2/química , Microglobulina beta-2/metabolismoRESUMO
Dyes like CR are able to inhibit the aggregation of Aß fibrils. Thus, a screening of a series of dyes including ABBB (1) was performed. Its main component 2 tested in an in vitro assay (i.e., ThT assay) showed good potency at inhibiting fibrils association. Congeners 4-9 have been designed and synthesized as inhibitors of Aß aggregation. A number of these newly synthesized compounds have been found to be active in the ThT assay with IC(50) of 1-57.4 µM. The most potent compound of this series, 4k, showed micromolar activity in this test. Another potent derivative 4q (IC(50) = 5.6 µM) rapidly crossed the blood-brain barrier, achieving whole brain concentrations higher than in plasma. So 4q could be developed to find novel potent antiaggregating ßA agents useful in Alzheimer disease as well as other neurological diseases characterized by deposits of amyloid aggregates.
Assuntos
Amiloide/metabolismo , Naftalenos/síntese química , Amiloide/química , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Animais , Barreira Hematoencefálica/metabolismo , Desenho de Fármacos , Camundongos , Naftalenos/química , Naftalenos/farmacologia , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Relação Estrutura-Atividade , Distribuição TecidualRESUMO
Despite recent progress in the fight against malaria, the emergence and spread of drug-resistant parasites remains a serious obstacle to the treatment of infections. We recently reported the development of a novel antimalarial drug that combines the 4-aminoquinoline pharmacophore of chloroquine with that of clotrimazole-based antimalarials. Here we describe the optimization of this class of hybrid drug through in-depth structure-activity relationship studies. Antiplasmodial properties and mode of action were characterized in vitro and in vivo, and interactions with the parasite's 'chloroquine resistance transporter' were investigated in a Xenopus laevis oocyte expression system. These tests indicated that piperazine derivatives 4b and 4d may be suitable for coadministration with chloroquine against chloroquine-resistant parasites. The potential for metabolism of the drugs by cytochrome P450 was determined in silico, and the lead compounds were tested for toxicity and mutagenicity. A preliminary pharmacokinetic analysis undertaken in mice indicated that compound 4b has an optimal half-life.
Assuntos
Aminoquinolinas/síntese química , Antimaláricos/síntese química , Clotrimazol/análogos & derivados , Clotrimazol/síntese química , Aminoquinolinas/farmacocinética , Aminoquinolinas/farmacologia , Animais , Antimaláricos/farmacocinética , Antimaláricos/farmacologia , Transporte Biológico , Linhagem Celular , Cloroquina/farmacocinética , Cloroquina/farmacologia , Clotrimazol/farmacocinética , Clotrimazol/farmacologia , Resistência a Medicamentos , Feminino , Meia-Vida , Hemeproteínas/antagonistas & inibidores , Hemeproteínas/biossíntese , Humanos , Malária/tratamento farmacológico , Malária/parasitologia , Masculino , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/fisiologia , Camundongos , Modelos Moleculares , Mutação , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Piperazinas/síntese química , Piperazinas/farmacocinética , Piperazinas/farmacologia , Plasmodium berghei , Plasmodium falciparum/efeitos dos fármacos , Proteínas de Protozoários/genética , Proteínas de Protozoários/fisiologia , Ratos , Ratos Sprague-Dawley , Estereoisomerismo , Relação Estrutura-Atividade , Pressão Ventricular/efeitos dos fármacos , Xenopus laevisRESUMO
Antimalarial agents structurally based on novel pharmacophores, synthesized by low-cost synthetic procedures and characterized by low potential for developing resistance are urgently needed. Recently, we developed an innovative class of antimalarials based on a polyaromatic pharmacophore. Hybridizing the 4-aminoquinoline or the 9-aminoacridine system of known antimalarials with the clotrimazole-like pharmacophore, characterized by a polyarylmethyl group, we describe herein the development of a unique class (4a-l and 5a-c) of antimalarials selectively interacting with free heme and interfering with Plasmodium falciparum (Pf) heme metabolism. Combination of the polyarylmethyl system, able to form and stabilize radical intermediates, with the iron-complexing and conjugation-mediated electron transfer properties of the 4(9)-aminoquinoline(acridine) system led to potent antimalarials in vitro against chloroquine sensitive and resistant Pf strains. Among the compounds synthesized, 4g was active in vivo against P. chabaudi and P. berghei after oral administration and, possessing promising pharmacokinetic properties, it is a candidate for further preclinical development.
Assuntos
Aminoquinolinas/farmacologia , Antimaláricos/farmacologia , Clotrimazol/farmacologia , Aminoquinolinas/química , Aminoquinolinas/farmacocinética , Animais , Antimaláricos/síntese química , Antimaláricos/farmacocinética , Linhagem Celular , Clotrimazol/química , Clotrimazol/farmacocinética , Humanos , Espectroscopia de Ressonância Magnética , Camundongos , Plasmodium/efeitos dos fármacos , Ratos , Especificidade da Espécie , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Previous structure-activity relationship studies in the search for a potent, noncompetitive alpha-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor antagonist led to 2,3-dimethyl-6-phenyl-12H-[1,3]dioxolo[4,5-h]imidazo[1,2-c][2,3]benzodiazepine (ZK 187638). However, the first synthesis had some drawbacks regarding reagents, processes, and overall yield, which furthermore decreased when the synthesis was scaled up. Therefore, we now report a new synthetic route for this compound which requires fewer steps and is suited for large-scale production. This compound significantly relieved the symptoms of neuromuscular deficit in mnd mice, a model of neuronal ceroid lipofuscinosis with motor neuron dysfunction. After oral administration, the concentrations of the compound in the brain and spinal cord were about threefold higher than those in the plasma. In summary, this novel AMPA antagonist is accessible through an optimized synthetic route, has good neurobehavioral activity, oral bioavailability, and favorable brain penetration. This opens new possibilities for the treatment of devastating neurological diseases that are mediated by the AMPA receptor.
Assuntos
Comportamento Animal/efeitos dos fármacos , Benzodiazepinas/síntese química , Benzodiazepinas/uso terapêutico , Dioxóis/síntese química , Dioxóis/uso terapêutico , Destreza Motora/efeitos dos fármacos , Lipofuscinoses Ceroides Neuronais/tratamento farmacológico , Receptores de AMPA/antagonistas & inibidores , Administração Oral , Fatores Etários , Animais , Benzodiazepinas/administração & dosagem , Sistema Nervoso Central/efeitos dos fármacos , Dioxóis/administração & dosagem , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Masculino , Camundongos , Camundongos Mutantes Neurológicos , Estrutura Molecular , Lipofuscinoses Ceroides Neuronais/fisiopatologiaRESUMO
We examined the blood-brain barrier (BBB) function in methylazoxymethanol acetate (MAM)-treated rats, a model of human developmental brain malformations. We found aberrant vessels morphology and serum albumin leakage in the heterotopic (malformed) hippocampus; these changes were associated with a significant increase in endothelial P-glycoprotein (P-gp) expression. Seizures exacerbated BBB leakage and greatly augmented P-gp expression in vessels and additionally in perivascular/parenchymal astrocytes. The effects of seizures were observed to a much larger extent in malformed than in normal brain tissue. The intrinsic changes in BBB function in MAM-exposed rats were associated with increased blood-to-brain penetration of ondansetron, a P-gp substrate. However, a marked reduction in drug brain levels was provoked by seizures, and this effect was reversed by selective blockade of P-gp activity with tariquidar. Changes in BBB function may critically contribute to determine the brain uptake and distribution of P-gp substrates in epileptic tissue associated with developmental malformations.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Barreira Hematoencefálica/metabolismo , Células Endoteliais/metabolismo , Epilepsia/metabolismo , Hipocampo , Convulsões/metabolismo , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Animais , Anticonvulsivantes/farmacocinética , Astrócitos/metabolismo , Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/anormalidades , Encéfalo/irrigação sanguínea , Permeabilidade Capilar/efeitos dos fármacos , Permeabilidade Capilar/fisiologia , Coristoma/induzido quimicamente , Modelos Animais de Doenças , Resistência a Medicamentos/fisiologia , Células Endoteliais/efeitos dos fármacos , Epilepsia/patologia , Feminino , Masculino , Análise por Pareamento , Acetato de Metilazoximetanol , Ondansetron/farmacocinética , Gravidez , RNA Mensageiro/análise , Ratos , Convulsões/patologia , Albumina Sérica/metabolismoRESUMO
Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder involving the selective degeneration of motor neurons. In a small proportion of patients, ALS is caused by mutations in copper/zinc superoxide dismutase (SOD1), and mice overexpressing SOD1(G93A) mutant develop a syndrome that closely resembles the human disease. Excitotoxicity mediated by glutamate AMPA receptors has been suggested to be implicated in the selective susceptibility of motor neurons occurring in ALS. In SOD1(G93A) mice, we found that levels of GluR2 AMPA subunit, which plays a pivotal role in the maintenance of calcium impermeability of AMPA receptors, are decreased in spinal motor neurons before symptom onset in concomitance with a modest increase of GluR3 expression, a calcium-permeable AMPA subunit. This effect can result in a higher number of calcium-permeable AMPA receptors on motor neurons of SOD1(G93A) mice, predisposing these cells to be injured by AMPA-mediated glutamate firing. In support of this, we showed that treatment with a new noncompetitive AMPA antagonist, ZK 187638, partially protected motor neurons, improved motor function, and prolonged the survival of SOD1(G93A) mice.
Assuntos
Esclerose Lateral Amiotrófica/tratamento farmacológico , Benzodiazepinas/uso terapêutico , Dioxóis/uso terapêutico , Antagonistas de Aminoácidos Excitatórios/uso terapêutico , Neurônios Motores/fisiologia , Receptores de AMPA/antagonistas & inibidores , Superóxido Dismutase/genética , Esclerose Lateral Amiotrófica/mortalidade , Esclerose Lateral Amiotrófica/patologia , Animais , Comportamento Animal/efeitos dos fármacos , Benzodiazepinas/farmacocinética , Western Blotting , Colina O-Acetiltransferase/genética , Colina O-Acetiltransferase/metabolismo , Dioxóis/farmacocinética , Antagonistas de Aminoácidos Excitatórios/farmacocinética , Humanos , Imuno-Histoquímica , Hibridização In Situ , Locomoção/efeitos dos fármacos , Locomoção/genética , Locomoção/fisiologia , Camundongos , Camundongos Transgênicos , Equilíbrio Postural/efeitos dos fármacos , Equilíbrio Postural/fisiologia , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Receptores de AMPA/biossíntese , Receptores de AMPA/genética , Superóxido Dismutase-1 , SobrevidaRESUMO
PURPOSE: We measured the brain-to-plasma partition of 10,11-dihydro-10-hydroxy-5H-dibenzo(b,f)azepine-5-carboxamide (10-OHCBZ) in epilepsy patients undergoing surgery to alleviate drug-resistant seizures and administered with different oral doses of oxcarbazepine (OXC). We addressed the possible contribution of the multidrug transporter P-glycoprotein (P-gp or MDR1) in determining 10-OHCBZ brain levels by measuring whether this active metabolite is a substrate of P-gp and the relation between the level of expression of MDR1 and the drug concentration in the same brain tissue specimens. METHODS: Steady-state plasma and brain concentrations (C(ss)) of 10-OHCBZ were determined intraoperatively in 11 patients by high-performance liquid chromatography (HPLC) with UV detection. The level of expression of MDR1 mRNA was measured in surgically resected brain tissue by reverse transcriptase polymerase chain reaction (RT-PCR). The ability of 10-OHCBZ to act as substate of P-gp was evaluated by measuring its uptake in cell lines expressing different levels of P-gp, in the presence or absence of a selective P-gp inhibitor. RESULTS: OXC was converted to 10-OHCBZ and to Di-OHCBZ, the two main metabolites measured in plasma. The brain concentrations of the active metabolite 10-OHCBZ did not reflect plasma C(ss). A significant inverse linear correlation was found between 10-OHCBZ brain-to-plasma concentration ratio and the level of brain expression of MDR1 mRNA. In vitro uptake studies demonstrated lower intracellular 10-OHCBZ levels in cells with higher P-gp expression. Intracellular drug concentration was increased by XR9576, a specific P-gp blocker. CONCLUSIONS: Pharmacologic failure of OXC in pharmacoresistant epilepsy is unlikely to be due to alterations in drug metabolism. 10-OHCBZ does not appear to cross the blood-brain barrier by simple diffusion, and it acts as a substrate of P-gp. The level of expression of MDR1 is inversely correlated with 10-OHCBZ concentration in the epileptic tissue. P-gp may play a role in the pharmacoresistance to OXC by determining the attainment of insufficient concentrations of its active metabolite at neuronal targets.