RESUMEN
New effective compounds to treat tuberculosis are urgently needed. IQG-607 is an orally active anti-tuberculosis drug candidate, with promising preliminary safety profile and anti-mycobacterial activity in both in vitro and in vivo models of tuberculosis infection. Here, we evaluated the mutagenic and genotoxic effects of IQG-607, and its interactions with CYP450 isoforms. Moreover, we describe for the first time a combination study of IQG-607 in Mycobacterium tuberculosis-infected mice. Importantly, IQG-607 had additive effects when combined with the first-line anti-tuberculosis drugs rifampin and pyrazinamide in mice. IQG-607 presented weak to moderate inhibitory potential against CYP450 isoforms 3A4, 1A2, 2C9, 2C19, 2D6, and 2E1. The Salmonella mutagenicity test revealed that IQG-607 induced base pair substitution mutations in the strains TA100 and TA1535. However, in the presence of human metabolic S9 fraction, no mutagenic effect was detected in any strain. Additionally, IQG-607 did not increase micronucleus frequencies in mice, at any dose tested, 25, 100, or 250 mg/kg. The favorable activity in combination with first-line drugs and mild to moderate toxic events described in this study suggest that IQG-607 represents a candidate for clinical development.
Asunto(s)
Antibacterianos/farmacología , Inhibidores Enzimáticos/farmacología , Compuestos Ferrosos/efectos adversos , Compuestos Ferrosos/farmacología , Isoniazida/análogos & derivados , Mycobacterium tuberculosis/efectos de los fármacos , Salmonella typhimurium/efectos de los fármacos , Tuberculosis/tratamiento farmacológico , Animales , Antibacterianos/administración & dosificación , Antibacterianos/efectos adversos , Aberraciones Cromosómicas , Sistema Enzimático del Citocromo P-450/metabolismo , Modelos Animales de Enfermedad , Quimioterapia Combinada , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/efectos adversos , Compuestos Ferrosos/administración & dosificación , Isoniazida/administración & dosificación , Isoniazida/efectos adversos , Isoniazida/farmacología , Masculino , Ratones , Pruebas de Sensibilidad Microbiana , Pruebas de Mutagenicidad , Mycobacterium tuberculosis/genética , Salmonella typhimurium/genética , Tuberculosis/microbiologíaRESUMEN
Mycobacterium tuberculosis is clinically recognized as a causative agent of Tuberculosis. Keeping in view, this study was endeavored to screen our previously synthesized seventeen INH analogues for their antimycobacterial potential using proportion method. During this process, INH and all the seventeen compounds were examined at different concentrations of 0.05, 0.1 and 0.2µg/mL which were prepared using Lowenstein-Jensen (LJ) base. For drug susceptibility test, three Mycobacterial strains ATCC H37Rv, known INH-sensitive and INH-resistant strains were selected, sub-cultured on LJ Medium and serial diluted to achieve 1:10, 1:100, 1:1000 and 1:10000 from calibrated bacterial suspension Mcfarland No. 1. Dilutions of 1:100 and 1:10000 were added to drug free medium and 1:100 bacterial suspension was added to each of the test concentrations and finally incubated for 4-6 weeks at 37°C. It was observed that only compounds II and XI were active against MTb. Compounds III, IX and X also showed activity but were less potent. Ligand Scout 3.02[il_10] was used to perform pharmacophore-based screening where important pharmacophoric features were identified in the structures of these compounds which could be related to their observed antimycobacterial activity.
Asunto(s)
Antituberculosos/química , Antituberculosos/farmacología , Isoniazida/análogos & derivados , Evaluación Preclínica de Medicamentos/métodos , Isoniazida/química , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Mycobacterium tuberculosis/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
The emergence of multidrug-resistant strains of Mycobacterium tuberculosis (MTB) represents a major threat to global health. Isoniazid (INH) is a prodrug used in the first-line treatment of tuberculosis. It undergoes oxidation by a catalase-peroxidase KatG, leading to generation of an isonicotinoyl radical that reacts with NAD(H) forming the INH-NADH adduct as the active metabolite. A redox-mediated activation of isoniazid using an iron metal complex was previously proposed as a strategy to overcome isoniazid resistance due to KatG mutations. Here, we have prepared a series of iron metal complexes with isoniazid and analogues, containing alkyl substituents at the hydrazide moiety, and also with pyrazinamide derivatives. These complexes were activated by H2O2 and studied by ESR and LC-MS. For the first time, the formation of the oxidized INH-NAD adduct from the pentacyano(isoniazid)ferrate(II) complex was detected by LC-MS, supporting a redox-mediated activation, for which a mechanistic proposition is reported. ESR data showed all alkylated hydrazides, in contrast to non-substituted hydrazides, only generated alkyl-based radicals. The structural modifications did not improve minimal inhibitory concentration (MIC) against MTB in comparison to isoniazid iron complex, providing support to isonicotinoyl radical formation as a requirement for activity. Nonetheless, the pyrazinoic acid hydrazide iron complex showed redox-mediated activation using H2O2 with generation of a pyrazinoyl radical intermediate and production of pyrazinoic acid, which is in fact the active metabolite of pyrazinamide prodrug. Thereby, this strategy can also unveil new opportunities for activation of this type of drug.
Asunto(s)
Antituberculosos/farmacología , Complejos de Coordinación/farmacología , Compuestos Ferrosos/farmacología , Isoniazida/análogos & derivados , Isoniazida/farmacología , Antituberculosos/síntesis química , Antituberculosos/química , Complejos de Coordinación/síntesis química , Complejos de Coordinación/química , Compuestos Ferrosos/síntesis química , Compuestos Ferrosos/química , Isoniazida/síntesis química , Isoniazida/química , Pruebas de Sensibilidad Microbiana , Modelos Químicos , Mycobacterium tuberculosis/efectos de los fármacos , Oxidación-ReducciónRESUMEN
IQG-607 is an anti-tuberculosis drug candidate, with a promising safety and efficacy profile in models of tuberculosis infection both in vitro and in vivo. Here, we evaluated the safety and the possible toxic effects of IQG-607 after acute and 90-day repeated administrations in minipigs. Single oral administration of IQG-607 (220 mg/kg) to female and male minipigs did not result in any morbidity or mortality. No gross lesions were observed in the minipigs at necropsy. Repeated administration of IQG 607 (65, 30, or 15 mg/kg), given orally, for 90 days, in both male and female animals did not cause any mortality and no significant body mass alteration. Diarrhea and alopecia were the clinical signs observed in animals dosed with IQG-607 for 90 days. Long-term treatment with IQG-607 did not induce evident alterations of blood cell counts or any hematological parameters. Importantly, the repeated schedule of administration of IQG-607 resulted in increased cholesterol levels, increased glucose levels, decrease in the globulin levels, and increased creatinine levels over the time. Most necropsy and histopathological alterations of the organs from IQG-607-treated groups were also observed for the untreated group. In addition, pharmacokinetic parameters were evaluated. IQG-607 represents a potential candidate molecule for anti-tuberculosis drug development programs. Its promising in vivo activity and mild to moderate toxic events detected in this study suggest that IQG-607 represents a candidate for clinical development.
Asunto(s)
Alopecia/inducido químicamente , Antituberculosos/toxicidad , Diarrea/inducido químicamente , Compuestos Ferrosos/toxicidad , Isoniazida/análogos & derivados , Administración Oral , Animales , Antituberculosos/farmacocinética , Evaluación Preclínica de Medicamentos , Femenino , Compuestos Ferrosos/farmacocinética , Isoniazida/farmacocinética , Isoniazida/toxicidad , Masculino , Modelos Animales , Porcinos , Porcinos Enanos , Factores de Tiempo , Pruebas de Toxicidad/métodosRESUMEN
OBJECTIVE: In order to detect the in vitro synergistic effect of 4 drugs-pasiniazid (PA), moxifloxacin, rifabutin and rifapentini on multidrug-resistant mycobacterium tuberculosis (MDR-MTB) and extensively drug-resistant mycobacterium tuberculosis(XDR-MTB), which were core drugs of"The program of retreatment research of tuberculosis". METHOD: The checkerboard method was used to detect the minimum inhibitory concentration (MIC) of antituberculosis drug combination schemes (moxifloxacin-PA, moxifloxacin-PA-rifabutin and moxifloxacin-PA-rifapentini) to 40 strains of clinical drug resistant MTB(20 strains of MDR-MTB and 20 XDR-MTB) and the standard strain H37Rv, by calculating the fractional inhibitory concentration index of joint action in vitro to judge the combined effect, with fractional inhibitory concentration index(FICI)≤0.5 and FICI≤0.75 as the basis of 2 drugs and 3 drugs showing synergy. RESULTS: The FICI of moxifloxacin-PA scheme for DR-MTB was 0.125 to 1.000, only 5 strains with a FICI ≤0.5, showing synergistic effect. The FICI of moxifloxacin-Pa-rifabutin scheme with 20 strains of MDR-MTB ranged from 0.310 to 1.260, 10 strains with a FICI≤0.75, showing synergistic effect. The FICI of moxifloxacin-PA-rifabutin scheme with 20 strains of XDR-MTB ranged from 0.215 to 1.250, 11 strains with a FICI≤0.75, showing synergistic effect. The FICI of moxifloxacin-PA-rifapentini scheme with 20 strains of MDR-MTB ranged from 0.150 to 0.780, 19 strains with a FICI≤0.75, showing synergistic effect. The FICI of moxifloxacin-PA-rifapentini scheme with 20 strains of XDR-MTB ranged from 0.200 to 1.280, 16 strains with a FICI≤0.75, showing synergistic effect. CONCLUSIONS: The synergistic effect of moxifloxacin-PA scheme was poor, but showing better synergy when further combined with rifabutin or rifapentini. Rifabutin showed better effect than rifapentini, but the synergistic effect of moxifloxacin-PA-rifabutin combination scheme was poor than that of moxifloxacin-PA-rifapentini combination scheme.
Asunto(s)
Antibióticos Antituberculosos/uso terapéutico , Tuberculosis Extensivamente Resistente a Drogas/tratamiento farmacológico , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Ácidos Aminosalicílicos/uso terapéutico , Sinergismo Farmacológico , Quimioterapia Combinada , Fluoroquinolonas/uso terapéutico , Isoniazida/análogos & derivados , Isoniazida/uso terapéutico , Pruebas de Sensibilidad Microbiana , Moxifloxacino , Retratamiento , Rifabutina/uso terapéutico , Rifampin/análogos & derivados , Rifampin/uso terapéuticoRESUMEN
The two ionophores N'(N',Nâ´E,N',Nâ´E)-N',Nâ´-((((oxybis(ethane-2,1-diyl))bis(oxy)) bis(2,1-phenylene))bis(methanylylidene))di(isonicotinohydrazide) (I1) and (N',Nâ´E,N',Nâ´E)-N',Nâ´-(((propane-1,3-diylbis(oxy))bis(2,1-phenylene))bis(methanylylidene))di(isonicotinohydrazide) (I2) were synthesised and investigated as neutral carrier in the fabrication of Mn(2+) ion selective sensor. Several membranes were prepared by incorporating different plasticizers and anionic excluders and their effect on potentiometric response was studied. The best analytical performance was obtained with the electrode having a membrane of composition of I2: PVC: o-NPOE: NaTPB in the ratio of 6:34:58:2 (w/w, mg). Comparative studies of coated graphite electrode (CGE) and coated pyrolytic graphite electrode (CPGE) based on I2 reveal the superiority of CPGE. The CPGE exhibits wide working concentration range of 1.23×10(-8)-1.0×10(-1) mol L(-1) and a detection limit down to 4.78×10(-9) mol L(-1) with a Nernstian slope of 29.5±0.4 mV decade(-1) of activity. The sensor performs satisfactorily over a wide pH range (3.5-9.0) and exhibited a quick response time (9s). The sensor can work satisfactorily in water-acetonitrile and water-methanol mixtures. It can tolerate 30% acetonitrile and 20% methanol content in the mixtures. The sensor could be used for a period of four months without any significant divergence in performance. The sensor reflects its utility in the quantification of Mn(2+) ion in real samples and has been successfully employed as an indicator electrode in the potentiometric titration of Mn(2+) ion with ethylenediaminetetraacetic acid (EDTA).
Asunto(s)
Materiales Biocompatibles Revestidos/química , Grafito/química , Hidrazonas/química , Isoniazida/análogos & derivados , Isoniazida/química , Manganeso/análisis , Nanopartículas/química , Calibración , Cationes , Conductividad Eléctrica , Electroquímica , Concentración de Iones de Hidrógeno , Electrodos de Iones Selectos , Ionóforos/química , Membranas Artificiales , Plantas Medicinales/química , Suelo/química , Soluciones , Temperatura , Factores de Tiempo , Verduras/química , Agua/químicaRESUMEN
Tuberculosis (TB) is the second cause of death from a single infectious agent, the M. tuberculosis bacillus. Nearly two billion people are infected and about 8.7 million new cases and 1.4 million deaths were reported by the World Health Organization (WHO) in 2013. Despite the availability of effective treatment, the alarming emergence of multidrug resistant (MDR) strains (with 310.000 estimated cases in 2011 among notified patients with pulmonary TB), simultaneously resistant to the two most effective anti-TB drugs, isoniazid (INH) and rifampicin, has urged the need to develop new molecular scaffolds, either structurally original or based on old and active drugs. The aim of this review is to summarize the current status of different QSAR based strategies for the design of novel anti-TB drugs based upon the most active anti-TB agent known, INH. A case study puts in evidence that the judicious application of quantitative structure- activity relationships can be successfully used to rationally design new INH-based derivatives, active against INH-resistant strains harboring mutations in the most frequent resistance related target (katG), and therefore develop candidate-compounds against MDR-TB, thus revisiting the unique effectiveness of INH against TB.
Asunto(s)
Antituberculosos/química , Biología Computacional , Descubrimiento de Drogas/métodos , Isoniazida/análogos & derivados , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Antituberculosos/farmacología , Antituberculosos/uso terapéutico , Ensayos Clínicos como Asunto , Evaluación Preclínica de Medicamentos , Quimioterapia Combinada , Humanos , Isoniazida/química , Isoniazida/farmacología , Isoniazida/uso terapéutico , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/crecimiento & desarrollo , Análisis de Componente Principal , Relación Estructura-Actividad Cuantitativa , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Resistente a Múltiples Medicamentos/microbiologíaRESUMEN
We have previously demonstrated a potent in vitro inhibitory activity for two pentacyano(isoniazid)ferrate(II) compounds, namely IQG-607 and IQG-639, against the Mycobacterium tuberculosis enoyl-acyl carrier protein reductase enzyme. In this study, the activity of these compounds was evaluated using an in vivo murine model of tuberculosis. Swiss mice were infected with M. tuberculosis H37Rv strain and then IQG-607 or IQG-639 (250 mg/kg) was administered for 28 days or 56 days. In addition, a dose-response study was performed with IQG-607 at 5, 10, 25, 50, 100, 200 and 250 mg/kg. The activity of test compounds was compared with that of the positive control drug isoniazid (INH) (25 mg/kg). After 28 days or 56 days of treatment, both IQG-607 and INH significantly reduced M. tuberculosis-induced splenomegaly as well as significantly diminishing the colony-forming units in the spleen and lungs. IQG-607 and INH ameliorated the lung macroscopic aspect, reducing lung lesions to a similar extent. However, IQG-639 did not significantly modify any evaluated parameter. Experiments using early and late controls of infection revealed a bactericidal activity for IQG-607. IQG-607 might well represent a good candidate for clinical development as a new antimycobacterial agent.
Asunto(s)
Antituberculosos/farmacología , Isoniazida/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis/tratamiento farmacológico , Animales , Carga Bacteriana , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Compuestos Ferrosos/farmacología , Isoniazida/análogos & derivados , Pulmón/efectos de los fármacos , Pulmón/microbiología , Pulmón/patología , Enfermedades Pulmonares/tratamiento farmacológico , Enfermedades Pulmonares/microbiología , Masculino , Ratones , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/patogenicidad , Oxadiazoles/farmacología , Tuberculosis/microbiologíaRESUMEN
Structural modification of the frontline antitubercular isonicotinic acid hydrazide (INH) provides lipophilic adaptations (3-46) of the drug in which the hydrazine moiety of the parent compound has been chemically blocked from the deactivating process of N(2)-acetylation by N-arylaminoacetyl transferases. As a class, these compounds show high levels of activity against Mycobacterium tuberculosis in vitro and in tuberculosis-infected macrophages. They provide strong protection in tuberculosis-infected mice and have low toxicity. With some representatives of this class achieving early peak plasma concentrations approximately three orders of magnitude above minimum inhibitory concentration, they may serve as tools for improving our understanding of INH-based treatment modalities, particularly for those patients chronically underdosed in conventional INH therapy.
Asunto(s)
Antituberculosos/química , Antituberculosos/uso terapéutico , Isoniazida/química , Isoniazida/uso terapéutico , Mycobacterium tuberculosis/efectos de los fármacos , Bases de Schiff/química , Tuberculosis/tratamiento farmacológico , Animales , Antituberculosos/farmacología , Femenino , Isoniazida/análogos & derivados , Isoniazida/farmacología , Macrófagos/efectos de los fármacos , Macrófagos/microbiología , Ratones , Ratones Endogámicos C57BL , Pruebas de Sensibilidad Microbiana , Relación Estructura-ActividadRESUMEN
Iron (Fe) chelation therapy was initially designed to alleviate the toxic effects of excess Fe evident in Fe-overload diseases. However, the novel toxicological properties of some Fe chelator-metal complexes have shifted appreciable focus to their application in cancer chemotherapy. Redox-inactive Fe chelator complexes are well suited for the treatment of Fe-overload diseases, whereas Fe chelator complexes with high redox activity have shown promising results as chemotherapeutics against cancer. Within this perspective, we discuss the different modes of action and toxicological profiles of Fe chelators, including analogues of 2-pyridylcarboxaldehyde isonicotinoyl hydrazone, di-2-pyridylketone isonicotinoyl hydrazone, di-2-pyridylketone thiosemicarbazone, and the clinically trialed chelator 3-aminopyridine-2-carboxaldehyde thiosemicarbazone. The potential application of these agents in the changing face of Fe chelation therapy is discussed.
Asunto(s)
Terapia por Quelación , Hidrazonas/efectos adversos , Quelantes del Hierro/efectos adversos , Sobrecarga de Hierro/tratamiento farmacológico , Toxicología , Humanos , Hidrazonas/química , Quelantes del Hierro/química , Sobrecarga de Hierro/metabolismo , Isoniazida/efectos adversos , Isoniazida/análogos & derivados , Isoniazida/química , Piridinas/efectos adversos , Piridinas/química , Piridoxal/efectos adversos , Piridoxal/análogos & derivados , Piridoxal/química , Relación Estructura-Actividad , Tiosemicarbazonas/efectos adversos , Tiosemicarbazonas/químicaRESUMEN
A series of nevirapine derivatives has been synthesized in an effort to enhance the spectrum of chemotherapeutic properties for the effective treatment of AIDS and AIDS-related opportunistic infections. The nevirapine derivative bearing isoniazid moiety (3a) was found to be the most potent compound with EC50 of<0.0636 microM, CC50 of>1000 microM and selectivity index of>15,723 which also exhibited 90% inhibition against Mycobacterium tuberculosis at 6.25 microg/ml. Compound 3c showed 100% inhibition against M. tuberculosis and also exhibited potent antibacterial activity against 24 pathogenic bacteria with MIC less than 1 microg/ml.
Asunto(s)
Antibacterianos/síntesis química , Fármacos Anti-VIH/síntesis química , VIH-1 , Mycobacterium tuberculosis , Nevirapina/análogos & derivados , Nevirapina/síntesis química , Infecciones Oportunistas Relacionadas con el SIDA/prevención & control , Antibacterianos/farmacología , Fármacos Anti-VIH/farmacología , Línea Celular , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , VIH-1/efectos de los fármacos , VIH-1/fisiología , Humanos , Isoniazida/análogos & derivados , Isoniazida/síntesis química , Isoniazida/farmacología , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/efectos de los fármacos , Nevirapina/farmacología , Relación Estructura-Actividad , Replicación Viral/efectos de los fármacosRESUMEN
Although iron chelation therapy with deferoxamine (DFO) has changed life expectancy in thalassemic patients, compliance with the rigorous requirements of long-term subcutaneous DFO infusions is unsatisfactory. This problem underlines the current efforts for developing alternative, orally effective chelators to improve compliance and treatment results. For the patient with transfusional iron overload in whom results of DFO treatment are unsatisfactory, several orally effective agents are now available. The most important of the new generation of oral chelators are deferiprone and ICL670. Total iron excretion with deferiprone is less than with DFO, but deferiprone has a better ability to penetrate cell membranes and may have a better cardioprotective effect than DFO. Current studies of the clinical efficacy and tolerability of ICL670 indicate that at a single oral dose of 20 mg/kg daily, it may be as effective as parenteral DFO used at the standard dose of 40 mg/kg daily. Combined chelation treatment, employing a weak chelator that penetrates cells better, and a stronger chelator with efficient urinary excretion, may result in improved therapeutic effect through iron shuttling between the two compounds. The efficacy of combined chelation treatment is additive and offers an increased likelihood of success in patients previously failing DFO or deferiprone monotherapy.
Asunto(s)
Terapia por Quelación , Quelantes del Hierro/uso terapéutico , Administración Oral , Benzoatos/administración & dosificación , Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , Deferasirox , Deferiprona , Deferoxamina/administración & dosificación , Quimioterapia Combinada , Humanos , Infusiones Intravenosas , Quelantes del Hierro/administración & dosificación , Quelantes del Hierro/análisis , Sobrecarga de Hierro/prevención & control , Isoniazida/administración & dosificación , Isoniazida/análogos & derivados , Piridonas/efectos adversos , Piridonas/uso terapéutico , Piridonas/toxicidad , Piridoxal/administración & dosificación , Piridoxal/análogos & derivados , Sobrevida/fisiología , Triazoles/administración & dosificación , Talasemia beta/sangre , Talasemia beta/tratamiento farmacológico , Talasemia beta/mortalidadRESUMEN
OBJECTIVE: To observe the effects of the protocol combining levofloxacin, pasiniazide, M. Vaccae (V+D+M protocol) in the treatment of multi-drug resistant pulmonary tuberculosis (MDR-TB). METHOD: Ninety-seven cases of MDR-TB randomized into V+D+M treatment protocol group (n=50) and control group (n=47) were observed for the negative sputum conversion rate, focal absorption, pulmonary cavity closure and improvement of immune function, after a 6-month treatment course. RESULTS: After the completion of the treatment course, the negative sputum conversion rate in V+D+M treatment protocol group was 84%, significantly higher than that in the control group (42%); the former group showed a focal absorption rate and pulmonary cavity closure rate of 83% and 66%, which were 33% and 26% respectively in the latter. In V+D+M treatment protocol group, T lymphocyte subgroups CD(3) and CD(4) were significantly elevated while CD(8) decreased after treatment, resulting in increased CD(4) to CD(8) ratio. The incidence of adverse effects resulting from the different treatment protocols in the two groups were comparable (30% vs 38%). CONCLUSION: V+D+M treatment protocol is effective for MDR-TB, which possesses the potential for application in clinical practice.
Asunto(s)
Adyuvantes Inmunológicos/administración & dosificación , Ácido Aminosalicílico/administración & dosificación , Ácidos Aminosalicílicos , Isoniazida/análogos & derivados , Isoniazida/administración & dosificación , Levofloxacino , Ofloxacino/administración & dosificación , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Pulmonar/tratamiento farmacológico , Adolescente , Adulto , Anciano , Protocolos Clínicos , Quimioterapia Combinada , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tuberculosis Resistente a Múltiples Medicamentos/inmunologíaRESUMEN
Although iron chelation therapy with deferoxamine (DFO) results in improved life expectancy of patients with thalassemia, compliance with parenteral DFO treatment is unsatisfactory, underlining the need for alternative drugs and innovative ways of drug administration. We examined the chelating potential of pyridoxal isonicotinoyl hydrazone (PIH) analogs, alone or in combination with DFO, using hypertransfused rats with labeled hepatocellular iron stores and cultured iron-loaded rat heart cells. Our in vivo studies using 2 representative PIH analogs, 108-o and 109-o, have shown that PIH analogs given orally are 2.6 to 2.8 times more effective in mobilizing hepatocellular iron in rats, on a weight-per-weight basis, than parenteral DFO administered intraperitoneally. The combined effect of DFO and 108-o on hepatocellular iron excretion was additive, and response at a dose range of 25 to 200 mg/kg was linear. In vitro studies in heart cells showed that DFO was more effective in heart cell iron mobilization than all PIH analogs studied. Response to joint chelation with DFO and PIH analogs was similar to an increase in the equivalent molar dose of DFO alone, rather than the sum of the separate effects of the PIH analog and DFO. This finding was most likely the result of iron transfer from PIH analogs to DFO, a conclusion supported directly by iron-shuttle experiments using fluorescent DFO. These findings provide a rationale for the combined, simultaneous use of iron-chelating drugs and may have useful, practical implications for designing novel strategies of iron chelation therapy.
Asunto(s)
Deferoxamina/farmacología , Corazón/fisiología , Quelantes del Hierro/farmacología , Hierro/metabolismo , Isoniazida/análogos & derivados , Isoniazida/farmacología , Piridoxal/análogos & derivados , Piridoxal/farmacología , Animales , Animales Recién Nacidos , Transfusión Sanguínea , Células Cultivadas , Femenino , Ferritinas/metabolismo , Corazón/efectos de los fármacos , Radioisótopos de Hierro , Cinética , Ratas , Ratas WistarRESUMEN
Iron overload secondary to beta-thalassemia and other iron-loading anemias is the most serious obstacle to be overcome in the treatment of these diseases, since there is no physiological mechanism for excretion of the excess iron acquired by chronic blood transfusion. Due to the inconvenience and cost of the current iron chelation therapy, the search for an orally available iron chelator is ongoing. Pyridoxal isonicotinoyl hydrazone (PIH) and many of its analogs are effective at mobilizing iron in vivo and in vitro at doses that are not toxic. PIH analogs were approximately equally effective at binding 59Fe within K562 cells; their efficacy depended upon the kinetics of release of the iron-chelator complex from the cell, which was correlated inversely with the lipophilicity of the chelators. Addition of BSA, which has a well-characterized affinity for lipophilic species, to the extracellular medium enhanced iron-chelator efflux, such that all analogs caused 59Fe release from the cells as quickly as it was chelated; this suggests that BSA acts as an extracellular sink for the iron-chelator complexes, many of which are highly lipophilic. The toxicity of the free chelators varied over two orders of magnitude, and was correlated with the amount of intracellular 59Fe-chelator complexes, implicating the complexes in the mechanism of toxicity of the chelators. Understanding the structural features that determine the efficacy and toxicity of iron chelators in biological systems is of value in the selection of PIH analogs for in vivo examination.
Asunto(s)
Antineoplásicos/farmacología , Quelantes del Hierro/farmacología , Hierro/metabolismo , Isoniazida/análogos & derivados , Isoniazida/farmacología , Piridoxal/análogos & derivados , Piridoxal/farmacología , Antineoplásicos/química , Transporte Biológico/efectos de los fármacos , División Celular/efectos de los fármacos , Humanos , Isoniazida/química , Células K562 , Piridoxal/químicaRESUMEN
The activities of six derivatives of a new class of isonicotinoylhydrazones were investigated in vitro against Mycobacterium tuberculosis H37Rv ATCC 27294, isoniazid-resistant M. tuberculosis ATCC 35822, rifampicin-resistant ATCC 35838, pyrazinamide-resistant ATCC 35828, streptomycin-resistant ATCC 35820 and 16 clinical isolates of M. tuberculosis. Several compounds showed interesting antimycobacterial activity against both ATCC strains and clinical isolates, but were less active against isoniazid-resistant M. tuberculosis. Combinations of five isonicotinoylhydrazone derivatives and rifampicin, ethambutol, para-aminosalicylic acid, isoniazid and clofazimine were also investigated against M. tuberculosis H37Rv ATCC 27294 and against ATCC drug-resistant strains. Addition of sub-MICs of some isonicotinoylhydrazone derivatives resulted in a four- to 16-fold reduction in MICs of ethambutol, para-aminosalicylic acid and rifampicin with fractional inhibitory concentrations (FICs) ranging between 0.17 and 0.37, suggesting a synergic interaction against M. tuberculosis H37Rv. Increased activity was also observed with other combinations (FICs 0.53-0.75), including isoniazid, and a synergic interaction between one of the isonicotinoylhydrazone derivatives and isoniazid (FIC 0.26) was shown against isoniazid-resistant M. tuberculosis ATCC 35822, whereas no effects were observed on combining the isonicotinoylhydrazones with clofazimine. The ability of isonicotinoylhydrazones to inhibit specifically the growth of M. tuberculosis, the high selectivity index and their ability to enhance the activity of standard antituberculous drugs in vitro indicate that they may serve as promising lead compounds for future drug development for the treatment of M. tuberculosis infections.
Asunto(s)
Antituberculosos/farmacología , Isoniazida/análogos & derivados , Isoniazida/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Ácido Aminosalicílico/química , Ácido Aminosalicílico/farmacología , Animales , Antiinflamatorios no Esteroideos/química , Antiinflamatorios no Esteroideos/farmacología , Antituberculosos/química , Antituberculosos/clasificación , Chlorocebus aethiops , Clofazimina/química , Clofazimina/farmacología , Evaluación Preclínica de Medicamentos/métodos , Evaluación Preclínica de Medicamentos/estadística & datos numéricos , Sinergismo Farmacológico , Quimioterapia Combinada , Etambutol/química , Etambutol/farmacología , Humanos , Hidrazonas/química , Hidrazonas/farmacología , Isoniazida/química , Isoniazida/clasificación , Pruebas de Sensibilidad Microbiana/estadística & datos numéricos , Mycobacterium tuberculosis/aislamiento & purificación , Rifampin/química , Rifampin/farmacología , Células VeroAsunto(s)
Quelantes del Hierro/farmacología , Isoniazida/análogos & derivados , Isoniazida/química , Isoniazida/farmacología , Piridoxal/análogos & derivados , Piridoxal/química , Piridoxal/farmacología , Animales , Antioxidantes/química , Antioxidantes/farmacología , Evaluación Preclínica de Medicamentos , Humanos , Técnicas In Vitro , Hierro/metabolismo , Quelantes del Hierro/química , Quelantes del Hierro/toxicidad , Sobrecarga de Hierro/tratamiento farmacológico , Sobrecarga de Hierro/metabolismo , Isoniazida/toxicidad , Estructura Molecular , Piridoxal/toxicidadRESUMEN
Pyridoxal isonicotinoyl hydrazone (PIH) is able to prevent iron-mediated hydroxyl radical formation by means of iron chelation and inhibition of redox cycling of the metal. In this study, we investigated the effect of PIH on Fe(II)-citrate-mediated lipid peroxidation and damage to isolated rat liver mitochondria. Lipid peroxidation was quantified by the production of thiobarbituric acid-reactive substances (TBARS) and by antimycin A-insensitive oxygen consumption. PIH at 300 microM induced full protection against 50 microM Fe(II)-citrate-induced loss of mitochondrial transmembrane potential (deltapsi) and mitochondrial swelling. In addition, PIH prevented the Fe(II)-citrate-dependent formation of TBARS and antimycin A-insensitive oxygen consumption. The antioxidant effectiveness of 100 microM PIH (on TBARS formation and mitochondrial swelling) was greater in the presence of 20 or 50 microM Fe(II)-citrate than in the presence of 100 microM Fe(II)-citrate, suggesting that the mechanism of PIH antioxidant action is linked with its Fe(II) chelating property. Finally, PIH increased the rate of Fe(II) autoxidation by sequestering iron from the Fe(II)-citrate complex, forming a Fe(III)-PIH, complex that does not participate in Fenton-type reactions and lipid peroxidation. These results are of pharmacological relevance since PIH is a potential candidate for chelation therapy in diseases related to abnormal intracellular iron distribution and/or iron overload.
Asunto(s)
Antioxidantes/farmacología , Compuestos Férricos/antagonistas & inhibidores , Quelantes del Hierro/farmacología , Isoniazida/análogos & derivados , Isoniazida/farmacología , Peroxidación de Lípido/efectos de los fármacos , Mitocondrias Hepáticas/metabolismo , Piridoxal/análogos & derivados , Piridoxal/farmacología , Animales , Quelantes/farmacología , Compuestos Férricos/farmacología , Técnicas In Vitro , Indicadores y Reactivos , Hierro/química , Potenciales de la Membrana/efectos de los fármacos , Mitocondrias Hepáticas/efectos de los fármacos , Oxidación-Reducción , Consumo de Oxígeno/efectos de los fármacos , Ratas , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismoRESUMEN
Iron chelating agents are essential for treating iron overload in diseases such as beta-thalassemia and are potentially useful for therapy in non-iron overload conditions, including free radical mediated tissue injury. Deferoxamine (DFO), the only drug available for iron chelation therapy, has a number of disadvantages (e.g., lack of intestinal absorption and high cost). The tridentate chelator pyridoxal isonicotinoyl hydrazone (PIH) has high iron chelation efficacy in vitro and in vivo with high selectivity and affinity for iron. It is relatively non-toxic, economical to synthesize and orally effective. We previously demonstrated that submillimolar levels of PIH and some of its analogues inhibit lipid peroxidation, ascorbate oxidation, 2-deoxyribose degradation, plasmid DNA strand breaks and 5,5-dimethylpyrroline-N-oxide (DMPO) hydroxylation mediated by either Fe(II) plus H(2)O(2) or Fe(III)-EDTA plus ascorbate. To further characterize the mechanism of PIH action, we studied the effects of PIH and some of its analogues on the degradation of 2-deoxyribose induced by Fe(III)-EDTA plus ascorbate. Compared with hydroxyl radical scavengers (DMSO, salicylate and mannitol), PIH was about two orders of magnitude more active in protecting 2-deoxyribose from degradation, which was comparable with some of its analogues and DFO. Competition experiments using two different concentrations of 2-deoxyribose (15 vs. 1.5 mM) revealed that hydroxyl radical scavengers (at 20 or 60 mM) were significantly less effective in preventing degradation of 2-deoxyribose at 15 mM than 2-deoxyribose at 1.5 mM. In contrast, 400 microM PIH was equally effective in preventing degradation of both 15 mM and 1.5 mM 2-deoxyribose. At a fixed Fe(III) concentration, increasing the concentration of ligands (either EDTA or NTA) caused a significant reduction in the protective effect of PIH towards 2-deoxyribose degradation. We also observed that PIH and DFO prevent 2-deoxyribose degradation induced by hypoxanthine, xanthine oxidase and Fe(III)-EDTA. The efficacy of PIH or DFO was inversely related to the EDTA concentration. Taken together, these results indicate that PIH (and its analogues) works by a mechanism different than the hydroxyl radical scavengers. It is likely that PIH removes Fe(III) from the chelates (either Fe(III)-EDTA or Fe(III)-NTA) and forms a Fe(III)-PIH(2) complex that does not catalyze oxyradical formation.
Asunto(s)
Ácido Ascórbico , Quelantes , Desoxirribosa/química , Compuestos Férricos , Isoniazida/análogos & derivados , Piridoxal/análogos & derivados , Daño del ADN , Dimetilsulfóxido , Ácido Edético , Depuradores de Radicales Libres , Radical Hidroxilo , Cinética , Modelos Químicos , Plásmidos , Relación Estructura-ActividadRESUMEN
Previous studies have demonstrated that aroylhydrazone iron (Fe) chelators of the pyridoxal isonicotinoyl hydrazone (PIH) class have high Fe chelation efficacy both in vitro and in vivo. Depending on their design, these drugs may have potential as agents for the treatment of Fe overload disease or cancer. Considering the high potential of this class of ligands, we have synthesized seven novel aroylhydrazones in an attempt to identify Fe chelators more efficient than desferrioxamine (DFO) and more soluble than those of the PIH class. These compounds belong to a new series of tridentate chelators known as the 2-pyridylcarboxaldehyde isonicotinoyl hydrazones (PCIH). In this study we have examined the Fe chelation efficacy and antiproliferative activity of these chelators including their effects on the expression of genes (WAF1 and GADD45) known to be important in mediating cell cycle arrest at G1/S. From seven chelators synthesized, three ligands, namely 2-pyridylcarbox-aldehyde benzoyl hydrazone (PCBH), 2-pyridylcarboxaldehyde m-bromobenzoyl hydrazone (PCBBH), and 2-pyridylcarboxaldehyde 2-thiophenecarboxyl hydrazone (PCTH), showed greater Fe chelation activity than DFO and comparable or greater efficiency than PIH. These ligands were highly effective at both mobilizing 59Fe from cells and preventing 59Fe uptake from 59Fe-transferrin and caused a marked increase in the RNA-binding activity of the iron-regulatory proteins (IRP). Our studies have also demonstrated that compared with the cytotoxic Fe chelator, 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311), these ligands have far less effect on cellular growth and 3H-thymidine, 3H-leucine, or 3H-uridine incorporation. In addition, in contrast to 311, which markedly increased WAF1 and GADD45 mRNA expression, PCBH and PCTH did not have any effect, whereas PCBBH increased the expression of GADD45 mRNA. Collectively, these results demonstrate the potential of several of these ligands as agents for the management of Fe overload disease.