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1.
Lima; IETSI; oct. 2020.
Non-conventional in Spanish | BRISA/RedTESA | ID: biblio-1359498

ABSTRACT

INTRODUCCIÓN: El presente dictamen preliminar expone la evaluación de la eficacia y seguridad de isavuconazol oral, en comparación con itraconazol oral, en pacientes adultos con aspergilosis invasiva con falla o intolerancia a voriconazol oral y posaconazol oral, que requieren terapia de mantenimiento posterior a la terapia de inducción con anfotericina B deoxicolato. La aspergilosis invasiva (AI) es la infección por hongos más común en huéspedes inmunodeprimidos. A pesar de los avances en el diagnóstico y el tratamiento de la AI, las tasas de mortalidad siguen siendo altas. A nivel mundial, se estima una incidencia acumulada anual de 250,000 casos de AI, con una tasa de mortalidad de aproximadamente 30 a 80 %. En el Perú, en el 2014 se estimó una prevalencia de 1,621 casos de AI. El tratamiento antimicótico de la AI suele ser prolongado, con una duración de varios meses a más de un año. En EsSalud, los pacientes con AI son tratados inicialmente con anfotericina B deoxicolato (terapia de inducción intravenosa) y luego, una vez estables, con azoles orales (voriconazol posaconazol o itraconazol) (terapia de mantenimiento). Sin embargo, basado en la opinión de expertos, es común que los pacientes con tratamiento prolongando presenten falla o intolerancia a la terapia de mantenimiento. Así, en un contexto clínico, en el que un paciente presenta falla o intolerancia a la terapia de mantenimiento con voriconazol oral y posaconazol oral, la única opción disponible a nivel institucional es el itraconazol oral. Sin embargo, la Red Prestacional Sabogal ha propuesto el uso de isavuconazol oral como alternativa al tratamiento con itraconazol oral, basándose en una mayor biodisponibilidad1 y menor tasa de efectos adversos serios asociados a interacciones farmacológicas, lo que podría llevar a una mejor eficacia y seguridad comparativa. Cabe mencionar que para este grupo específico de pacientes con AI, no se disponen de datos epidemiológicos a nivel institucional. METODOLOGÍA: Se realizó una búsqueda sistemática de literatura con el objetivo de identificar evidencia sobre la eficacia y seguridad de isavuconazol oral, en comparación con itraconazol oral, en pacientes adultos con aspergilosis invasiva con falla o intolerancia a voriconazol oral y posaconazol oral, que requieren terapia de mantenimiento posterior a la terapia de inducción con anfotericina B deoxicolato. Se utilizaron las bases de datos PubMed, Cochrane Library y LILACS, priorizándose la evidencia proveniente de ensayos clínicos controlados aleatorizados. Asimismo, se realizó una búsqueda dentro de bases de datos pertenecientes a grupos que realizan evaluación de tecnologías sanitarias (ETS) y guías de práctica clínica (GPC), incluyendo el Healthcare Improvement Scotland, el National Institute for Health and Care Excellence (NICE), la Canadian Agency for Drugs and Technologies in Health (CADTH), la Haute Autorité de Santé (HAS), el Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen (IQWiG), además de la Base Regional de Informes de Evaluación de Tecnologías en Salud de las Américas (BRISA) y páginas web de sociedades especializadas en aspergilosis como American Thoracic Society (ATS), Infectious Diseases Society of America (IDSA), European Society for Clinical Microbiology and Infectious Diseases (ESCMID) y European Conference on Infections in Leukaemia (ECIL). Se hizo una búsqueda adicional en la página web del registro administrado por la Biblioteca Nacional de Medicina de los Estados Unidos (https://clinicaltrials.gov/) e International Clinical Trial Registry Platform (ICTRP) (https://apps.who.int/trialsearch/), para poder identificar ensayos clínicos en curso o que no hayan sido publicados para, de este modo, disminuir el riesgo de sesgo de publicación. La búsqueda sistemática se basó en una metodología escalonada, la cual consistió en la búsqueda inicial de estudios secundarios (tipo revisiones sistemáticas de ensayos clínicos) que respondan a la pregunta PICO, seguido de la búsqueda de estudios primarios (tipo ensayos clínicos aleatorizados). RESULTADOS: Se realizó una búsqueda de la literatura con respecto a la eficacia y seguridad de isavuconazol oral, en comparación con itraconazol oral, en pacientes adultos con aspergilosis invasiva con falla o intolerancia a voriconazol oral y posaconazol oral, que requieren terapia de mantenimiento posterior a la terapia de inducción con anfotericina B deoxicolato. A continuación, se describe la evidencia disponible según el orden jerárquico del nivel de evidencia o pirámide de Haynes 6S9, siguiendo lo indicado en los criterios de elegibilidad. CONCLUSIONES: El presente dictamen preliminar tuvo como objetivo evaluar la mejor evidencia sobre la eficacia y seguridad de isavuconazol oral, en comparación con itraconazol oral, en pacientes adultos con aspergilosis invasiva con falla o intolerancia a voriconazol oral y posaconazol oral, que requieren terapia de mantenimiento posterior a la terapia de inducción con anfotericina B deoxicolato. En la presente evaluación no se encontró evidencia que sustentara un mayor beneficio con isavuconazol oral en lugar de itraconazol oral en pacientes adultos con aspergilosis invasiva con falla o intolerancia a voriconazol oral y posaconazol oral, que requieren terapia de mantenimiento posterior a la terapia de inducción con anfotericina B deoxicolato. Sin embargo, se identificaron recomendaciones vigentes basadas en la opinión de expertos y la experiencia clínica que abordaron el tema en cuestión. Así, tanto en la GPC de la ATS como en DynaMed se realizaron recomendaciones a favor del uso de itraconazol oral como terapia de mantenimiento luego de la inducción con anfotericina B intravenosa (deoxicolato o liposomal). Además, en el contexto específico de falla o intolerancia a azoles orales, se identificaron recomendaciones de GPC a favor del cambio de un azol a otro en pacientes con aspergilosis tratados a largo plazo con azoles orales. Por otro lado, no se encontraron recomendaciones sobre el uso de isavuconazol oral en el contexto clínico de interés. Así, considerando la ausencia de evidencia que apoye la superioridad de isavuconazol oral sobre itraconazol oral en la población de interés, las recomendaciones de GPC a favor del uso de itraconazol oral en el contexto clínico de interés y la disponibilidad de itraconazol oral en la institución, cuyo costo es 150 veces menor que el costo de isavuconazol oral, no es posible hacer una recomendación a favor del uso de isavuconazol oral. Por lo expuesto, el IETSI no aprueba el uso de isavuconazol oral en pacientes adultos con aspergilosis invasiva con falla o intolerancia a voriconazol oral y posaconazol oral, que requieren terapia de mantenimiento posterior a la terapia de inducción con anfotericina B deoxicolato.


Subject(s)
Humans , Ergosterol/antagonists & inhibitors , Invasive Pulmonary Aspergillosis/drug therapy , Voriconazole/adverse effects , Antifungal Agents/therapeutic use , Efficacy , Cost-Benefit Analysis
2.
Bioorg Chem ; 102: 104056, 2020 09.
Article in English | MEDLINE | ID: mdl-32653607

ABSTRACT

Leishmaniasis is an infectious disease caused by protozoan parasites of the genus Leishmania. The treatment of all forms of leishmaniasis relies on first-line drug, pentavalent antimonial, and in cases of drug failure, the second-line drug amphotericin B has been used. Besides the high toxicity of drugs, parasites can be resistant to antimonial in some areas of the World, making it necessary to perform further studies for the characterization of new antileishmanial agents. Thus, the aim of the present work was to evaluate the leishmanicidal activity of tolnaftate, a selective reversible and non-competitive inhibitor of the fungal enzyme squalene epoxidase, which is involved in the biosynthesis of ergosterol, essential to maintain membrane physiology in fungi as well as trypanosomatids. Tolnaftate eliminated promastigote forms of L. (L.) amazonensis, L. (V.) braziliensis and L. (L.) infantum (EC50 ~ 10 µg/mL and SI ~ 20 for all leishmanial species), and intracellular amastigote forms of all studied species (EC50 ~ 23 µg/mL in infections caused by dermatotropic species; and 11.7 µg/mL in infection caused by viscerotropic species) with high selectivity toward parasites [SI ~ 8 in infections caused by dermatotropic species and 17.4 for viscerotropic specie]. Promastigote forms of L. (L.) amazonensis treated with the EC50 of tolnaftate displayed morphological and physiological changes in the mitochondria and cell membrane. Additionally, promastigote forms treated with tolnaftate EC50 reduced the level of ergosterol by 5.6 times in comparison to the control parasites. Altogether, these results suggest that tolnaftate has leishmanicidal activity towards Leishmania sp., is selective, affects the cell membrane and mitochondria of parasites and, moreover, inhibits ergosterol production in L. (L.) amazonensis.


Subject(s)
Antifungal Agents/therapeutic use , Antiprotozoal Agents/therapeutic use , Ergosterol/antagonists & inhibitors , Leishmania/drug effects , Leishmaniasis/drug therapy , Tolnaftate/therapeutic use , Animals , Antifungal Agents/pharmacology , Antiprotozoal Agents/pharmacology , Cell Survival , Humans , Mice , Tolnaftate/pharmacology
3.
Antimicrob Agents Chemother ; 59(10): 6402-18, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26239973

ABSTRACT

Leishmaniases comprise a spectrum of diseases caused by protozoan parasites of the Leishmania genus. Treatments available have limited safety and efficacy, high costs, and difficult administration. Thus, there is an urgent need for safer and more-effective therapies. Most trypanosomatids have an essential requirement for ergosterol and other 24-alkyl sterols, which are absent in mammalian cells. In previous studies, we showed that Leishmania amazonensis is highly susceptible to aryl-quinuclidines, such as E5700, which inhibit squalene synthase, and to the azoles itraconazole (ITZ) and posaconazole (POSA), which inhibit C-14α-demethylase. Herein, we investigated the antiproliferative, ultrastructural, and biochemical effects of combinations of E5700 with ITZ and POSA against L. amazonensis. Potent synergistic antiproliferative effects were observed against promastigotes, with fractional inhibitory concentration (FIC) ratios of 0.0525 and 0.0162 for combinations of E5700 plus ITZ and of E5700 plus POSA, respectively. Against intracellular amastigotes, FIC values were 0.175 and 0.1125 for combinations of E5700 plus ITZ and E5700 plus POSA, respectively. Marked alterations of the ultrastructure of promastigotes treated with the combinations were observed, in particular mitochondrial swelling, which was consistent with a reduction of the mitochondrial transmembrane potential, and an increase in the production of reactive oxygen species. We also observed the presence of vacuoles similar to autophagosomes in close association with mitochondria and an increase in the number of lipid bodies. Both growth arrest and ultrastructural/biochemical alterations were strictly associated with the depletion of the 14-desmethyl endogenous sterol pool. These results suggest the possibility of a novel combination therapy for the treatment of leishmaniasis.


Subject(s)
14-alpha Demethylase Inhibitors/pharmacology , Ergosterol/antagonists & inhibitors , Itraconazole/pharmacology , Leishmania mexicana/drug effects , Pyridines/pharmacology , Quinuclidines/pharmacology , Triazoles/pharmacology , Trypanocidal Agents/pharmacology , Animals , Culture Media/chemistry , Drug Synergism , Drug Therapy, Combination , Ergosterol/biosynthesis , Farnesyl-Diphosphate Farnesyltransferase/antagonists & inhibitors , Farnesyl-Diphosphate Farnesyltransferase/metabolism , Humans , Leishmania mexicana/isolation & purification , Leishmania mexicana/metabolism , Leishmania mexicana/ultrastructure , Leishmaniasis, Diffuse Cutaneous/parasitology , Lipid Droplets/drug effects , Lipid Droplets/ultrastructure , Membrane Potential, Mitochondrial/drug effects , Mice , Mitochondria/drug effects , Mitochondria/metabolism , Mitochondria/ultrastructure , Parasitic Sensitivity Tests , Reactive Oxygen Species/agonists , Reactive Oxygen Species/metabolism , Sterol 14-Demethylase/metabolism
6.
Antimicrob Agents Chemother ; 57(5): 2167-70, 2013 May.
Article in English | MEDLINE | ID: mdl-23459491

ABSTRACT

Coccidioidomycosis is a systemic mycosis caused by the dimorphic fungi Coccidioides spp. The treatment for chronic and/or disseminated coccidioidomycosis can be prolonged and complicated. Therefore, the search for new drugs is necessary. Farnesol is a precursor in the sterol biosynthesis pathway that has been shown to present antifungal activity. Thus, the objective of this study was to evaluate the in vitro antifungal activity of farnesol alone and in combination with antifungal agents against clinical and environmental strains of Coccidioides posadasii as well as to determine their effect on the synthesis of ergosterol and on cell permeability. This study employed the broth macrodilution method to determine the MIC of farnesol against 18 strains of C. posadasii. Quantification of ergosterol was performed with 10 strains of C. posadasii after exposure to subinhibitory concentrations of farnesol. Finally, the activity of farnesol was evaluated in the presence of osmotic stress, induced by the addition of NaCl to the culture medium, during the susceptibility tests. The results showed that farnesol exhibited low MICs (ranging from 0.00171 to 0.01369 mg/liter) against all tested strains. The combination of farnesol with the antifungals showed synergistic effects (fractional inhibitory concentration index [FICI] ≤ 0.5). As for the ergosterol quantification, it was observed that exposure to subinhibitory concentrations of farnesol decreased the amount of ergosterol extracted from the fungal cells. Furthermore, farnesol also showed lower MIC values when the strains were subjected to osmotic stress, indicating the action of this compound on the fungal membrane. Thus, due to the high in vitro antifungal activity, this work brings perspectives for the performance of in vivo studies to further elucidate the effects of farnesol on the host cells.


Subject(s)
Antifungal Agents/pharmacology , Coccidioides/drug effects , Ergosterol/antagonists & inhibitors , Farnesol/pharmacology , Fluconazole/pharmacology , Cell Membrane Permeability/drug effects , Coccidioides/growth & development , Coccidioides/metabolism , Drug Synergism , Drug Therapy, Combination , Ergosterol/biosynthesis , Microbial Sensitivity Tests , Osmolar Concentration , Osmotic Pressure , Sodium Chloride/chemistry
7.
Med Mycol ; 51(5): 507-13, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23181601

ABSTRACT

Trichophyton rubrum is a worldwide agent responsible for chronic cases of dermatophytosis which have high rates of resistance to antifungal drugs. Attention has been drawn to the antimicrobial activity of aromatic compounds because of their promising biological properties. Therefore, we investigated the antifungal activity of eugenol against 14 strains of T. rubrum which involved determining its minimum inhibitory concentration (MIC) and effects on mycelial growth (dry weight), conidial germination and morphogenesis. The effects of eugenol on the cell wall (sorbitol protect effect) and the cell membrane (release of intracellular material, complex with ergosterol, ergosterol synthesis) were investigated. Eugenol inhibited the growth of 50% of T. rubrum strains employed in this study at an MIC = 256 µg/ml, as well as mycelial growth and conidia germination. It also caused abnormalities in the morphology of the dermatophyte in that we found wide, short, twisted hyphae and decreased conidiogenesis. The results of these studies on the mechanisms of action suggested that eugenol exerts antifungal effects on the cell wall and cell membrane of T. rubrum. Eugenol act on cell membrane by a mechanism that seems to involve the inhibition of ergosterol biosynthesis. The lower ergosterol content interferes with the integrity and functionality of the cell membrane. Finally, our studies support the potential use of the eugenol as an antifungal agent against T. rubrum.


Subject(s)
Antifungal Agents/pharmacology , Eugenol/pharmacology , Trichophyton/drug effects , Cell Membrane/drug effects , Cell Wall/drug effects , Ergosterol/antagonists & inhibitors , Ergosterol/biosynthesis , Microbial Sensitivity Tests , Mycelium/drug effects , Mycelium/growth & development , Spores, Fungal/drug effects , Spores, Fungal/growth & development , Trichophyton/growth & development
8.
Rio de Janeiro; s.n; 2013. xvi,132 p. ilus, tab, graf, mapas.
Thesis in Portuguese | LILACS | ID: lil-750994

ABSTRACT

Os tripanossomatídeos não sintetizam o colesterol e sim esteróis com o esqueleto ergostano, porém um percentual significativo de colesterol exógeno é encontrado em todas as espécies de Leishmania, sugerindo um papel biológico para esta molécula. Esta tese tem como objetivo estudar a importância do uso de colesterol para Leishmania spp. em várias situações, avaliando o potencial deste sistema como um possível alvo farmacológico. A atividade dos inibidores de biossíntese de ergosterol associado com inibidores de transporte de colesterol derivado de LDL, foi avaliada em promastigotas e amastigotas intracelulares. A associação entre LBqT01 e cetoconazol, miconazol ou terbinafina mostrou sinergia. A associação entre a imipramina ou progesterona e cetoconazol ou terbinafina indicaram um efeito aditivo. O cetoconazol e miconazol demonstraram uma diminuição de até duas vezes o valor de IC50 nas formas amastigotas, quando combinado com os inibidores de transporte de colesterol. Foi observado também alteração da biossíntese de ergosterol após tratamento dos parasitos com os inibidores de transporte de colesterol, demonstrado por CG/MS. A combinação de LBqT01 e cetoconazol mostrou ser mais ativa in vivo do que cada fármaco individualmente. Estudamos também o mecanismo de resistência desses inibidores, avaliando a modulação de enzimas da via de biossíntese de esteróis e a utilização de colesterol exógeno pelos parasitos. Promastigotas de Leishmania amazonensis, Leishmania braziliensis e Leishmania guyanensis foram cultivadas com concentrações crescentes de sinvastatina, terbinafina e miconazol. Estes inibidores mostraram um índice de resistência de 2,5 - 8 vezes. A resistência cruzada também foi avaliada, com estes inibidores e fármacos de referência (miltefosina, anfotericina B e antimônio trivalente)...


The trypanosomes do not synthesize cholesterol sterols but with ergostane skeleton, buta significant percentage of exogenous cholesterol is found in all species of Leishmania,suggesting a biological role for this molecule. This work aims to study the importanceof use cholesterol to Leishmania spp. in several cases, evaluating the potential of thesystem as a possible drug target. The activity of the inhibitors of ergosterol biosynthesisinhibitors associated with transport of LDL cholesterol derivative was evaluated inintracellular amastigotes and promastigotes. The association between LBqT01 andketoconazole, miconazole or terbinafine showed synergy. The association betweenimipramine or progesterone, and ketoconazole, or terbinafine indicated an additiveeffect. The ketoconazole and miconazole showed a reduction of up to twice the IC50value in amastigotes when combined with the inhibitors of cholesterol transport. Changeof ergosterol biosynthesis of parasites after treatment with inhibitors of cholesteroltransport as demonstrated by GC/MS was also observed. The combination of LBqT01and ketoconazole was more active in vivo than either drug individually. We also studiedthe mechanism of resistance of these inhibitors by evaluating the modulation ofenzymes of the sterol biosynthesis pathway and use of exogenous cholesterol byparasites. Promastigotes of Leishmania amazonensis, Leishmania braziliensis andLeishmania guyanensis were cultured with increasing concentrations of simvastatin,terbinafine and miconazole. These inhibitors showed resistance index from 2.5 to 8times. Cross-resistance was evaluated with these inhibitors and reference drugs(miltefosine, amphotericin B and trivalent antimony)...


Subject(s)
Ergosterol/antagonists & inhibitors , Ergosterol/biosynthesis , Sterols/biosynthesis , Leishmania , Leishmaniasis/drug therapy
9.
Mem Inst Oswaldo Cruz ; 104 Suppl 1: 311-8, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19753490

ABSTRACT

This article presents an overview of the currently available drugs nifurtimox (NFX) and benznidazole (BZN) used against Trypanosoma cruzi, the aetiological agent of Chagas disease; herein we discuss their limitations along with potential alternatives with a focus on ergosterol biosynthesis inhibitors (EBI). These compounds are currently the most advanced candidates for new anti-T. cruzi agents given that they block de novo production of 24-alkyl-sterols, which are essential for parasite survival and cannot be replaced by a host's own cholesterol. Among these compounds, new triazole derivatives that inhibit the parasite's C14alpha sterol demethylase are the most promising, as they have been shown to have curative activity in murine models of acute and chronic Chagas disease and are active against NFX and BZN-resistant T. cruzi strains; among this class of compounds, posaconazole (Schering-Plough Research Institute) and ravuconazole (Eisai Company) are poised for clinical trials in Chagas disease patients in the short term. Other T. cruzi-specific EBI, with in vitro and in vivo potency, include squalene synthase, lanosterol synthase and squalene epoxidase-inhibitors as well as compounds with dual mechanisms of action (ergosterol biosynthesis inhibition and free radical generation), but they are less advanced in their development process. The main putative advantages of EBI over currently available therapies include their higher potency and selectivity in both acute and chronic infections, activity against NFX and BZN-resistant T. cruzi strains, and much better tolerability and safety profiles. Limitations may include complexity and cost of manufacture of the new compounds. As for any new drug, such compounds will require extensive clinical testing before being introduced for clinical use, and the complexity of such studies, particularly in chronic patients, will be compounded by the current limitations in the verification of true parasitological cures for T. cruzi infections.


Subject(s)
Chagas Disease/drug therapy , Ergosterol/antagonists & inhibitors , Trypanocidal Agents/therapeutic use , Trypanosoma cruzi/drug effects , Acute Disease , Animals , Chronic Disease , Drug Design , Ergosterol/biosynthesis , Ergosterol/chemistry , Humans , Parasitic Sensitivity Tests , Trypanocidal Agents/chemistry
10.
Mem. Inst. Oswaldo Cruz ; 104(supl.1): 311-318, July 2009. ilus
Article in English | LILACS | ID: lil-520893

ABSTRACT

This article presents an overview of the currently available drugs nifurtimox (NFX) and benznidazole (BZN) used against Trypanosoma cruzi, the aetiological agent of Chagas disease; herein we discuss their limitations along with potential alternatives with a focus on ergosterol biosynthesis inhibitors (EBI). These compounds are currently the most advanced candidates for new anti-T. cruzi agents given that they block de novo production of 24-alkyl-sterols, which are essential for parasite survival and cannot be replaced by a host's own cholesterol. Among these compounds, new triazole derivatives that inhibit the parasite's C14± sterol demethylase are the most promising, as they have been shown to have curative activity in murine models of acute and chronic Chagas disease and are active against NFX and BZN-resistant T. cruzi strains; among this class of compounds, posaconazole (Schering-Plough Research Institute) and ravuconazole (Eisai Company) are poised for clinical trials in Chagas disease patients in the short term. Other T. cruzi-specific EBI, with in vitro and in vivo potency, include squalene synthase, lanosterol synthase and squalene epoxidase-inhibitors as well as compounds with dual mechanisms of action (ergosterol biosynthesis inhibition and free radical generation), but they are less advanced in their development process. The main putative advantages of EBI over currently available therapies include their higher potency and selectivity in both acute and chronic infections, activity against NFX and BZN-resistant T. cruzi strains, and much better tolerability and safety profiles. Limitations may include complexity and cost of manufacture of the new compounds. As for any new drug, such compounds will require extensive clinical testing before being introduced for clinical use, and the complexity of such studies, particularly in chronic patients, will be compounded by the current limitations in the verification of true parasitological...


Subject(s)
Animals , Humans , Chagas Disease/drug therapy , Ergosterol/antagonists & inhibitors , Trypanocidal Agents/therapeutic use , Trypanosoma cruzi/drug effects , Acute Disease , Chronic Disease , Drug Design , Ergosterol/biosynthesis , Ergosterol/chemistry , Parasitic Sensitivity Tests , Trypanocidal Agents/chemistry
11.
Rio de Janeiro; s.n; 2009. xiii,94 p. ilus, tab, graf.
Thesis in Portuguese | LILACS | ID: lil-556574

ABSTRACT

Todos os fármacos atualmente em uso para o tratamento da leishmaniose apresentam restrições, como toxicidade, graves efeitos colaterais, custo elevado, administração parenteral ou teratogenicidade. Desta forma, o desenvolvimento de fármacos mais eficazes e seletivos é de suma importância e a identificação de vias metabólicas exclusivas do parasito que possam ser usadas como alvo pode ser um ponto de partida interessante. Acredita-se que a leishmania não dependa da utilização do colesterol exógeno para sua sobrevivência, uma vez que sintetiza seus próprios esteróis. Porém, apesar disso, um percentual expressivo de colesterol é encontrado em suas membranas sendo, em alguns casos, o esterol majoritário indicando um papel biológico para essa molécula. O presente trabalho visa estudar a importância para a L. amazonensis da utilização do colesterol proveniente do soro, em diversas situações, avaliando o potencial desse sistema como um possível alvo farmacológico. A atividade dos inibidores da biossíntese do ergosterol (cetoconazol, miconazol, terbinafina e sinvastatina) foi avaliada, na presença de soro normal ou deslipidado. Foi observada que a privação das lipoproteínas do soro potencializa o efeito dos inibidores do ergosterol. Os promastigotas tratados com esses inibidores mostraram diferenças na sua composição lipídica, com acúmulo de colesterol nas células tratadas, principalmente, com cetoconazol e miconazol, indicando um possível mecanismo de compensação da leishmania, para suprir a inibição do ergosterol. Experimentos com LDL-I125, no qual tanto a leishmania tratada com cetoconazol, quanto a tratada com sinvastatina, que inibe o início da via de biossíntese de ergosterol, aumentaram a captação da LDL. A suramina, um inibidor da captação de LDL, mostrou uma diminuição do conteúdo de colesterol da leishmania e, em associação com a sinvastatina, obteve um efeito sinérgico, mostrando que o conteúdo da LDL, principalmente colesterol, pode estar envolvido na manutenção da integridade da membrana da célula. Em adição, a resistência ao cetoconazol induzida in vitro foi estudada. Foi observada uma relação direta entre o aumento da expressão gênica da C14-desmetilase com o nível de resistência induzido em promastigotas de L. amazonensis, sugerindo que esse seja o principal mecanismo de resistência a essa classe de fármacos. De uma maneira geral, a análise dos resultados como um todo sugere que o colesterol desempenhe um importante papel na atividade dos inibidores da biossíntese do ergosterol e que o bloqueio da sua utilização pode ser um possível alvo farmacológico.


Subject(s)
Cholesterol , Ergosterol/antagonists & inhibitors , Leishmania , Lipoproteins, LDL , Leishmaniasis/therapy , Sterols
12.
Int J Antimicrob Agents ; 27(6): 530-7, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16713188

ABSTRACT

We have previously shown that Trypanosoma cruzi-infected cardiomyocytes present alterations in cytoskeletal organisation in vitro. The remarkable change in the host cell cytoskeleton opened up the question of whether treatment of infected cells with antitrypanosomal compounds, such as ergosterol biosynthesis inhibitors (EBIs), allows the reconstruction of myofibrils and the microtubule network, restoring the cell biological function. Therefore, 48-h-old T. cruzi-infected cardiomyocyte cultures were treated with 10 nM ketoconazole or posaconazole and cytoskeletal remodelling of the host cells was analysed by indirect immunofluorescence assay. Both compounds displayed a potent antiparasitic effect and dramatically reduced the infection ratio. After 120 h of treatment, actin polygonal configuration was frequently visualised in the host cell cytoplasm, suggesting the initial stage of actin framework restoration. Rearrangement of myofibrils and the microtubule network was achieved 168 h after the start of drug treatment. Our data demonstrate that the trypanocidal effect of EBIs lead to reconstruction of the cytoskeleton of T. cruzi-infected cardiomyocytes in vitro.


Subject(s)
Cytoskeleton/drug effects , Ergosterol/biosynthesis , Ketoconazole/pharmacology , Myocytes, Cardiac/drug effects , Triazoles/pharmacology , Trypanocidal Agents/pharmacology , Trypanosoma cruzi/drug effects , Animals , Cells, Cultured , Cytoskeleton/chemistry , Ergosterol/antagonists & inhibitors , Mice , Myocytes, Cardiac/chemistry , Myofibrils/drug effects
13.
J Antimicrob Chemother ; 55(5): 780-4, 2005 May.
Article in English | MEDLINE | ID: mdl-15790672

ABSTRACT

OBJECTIVES: Investigation of the antiproliferative synergy of the lysophospholipid analogues (LPAs) edelfosine, ilmofosine and miltefosine with the ergosterol biosynthesis inhibitor ketoconazole against Trypanosoma cruzi. METHODS: The effect of LPAs, ketoconazole and their combination was evaluated against epimastigotes and intracellular amastigotes by the parameter IC50 leading to construction of isobolograms, for determination of a synergic effect. For epimastigotes, ultrastructural damage induced by these treatments was evaluated by transmission and scanning electron microscopy. RESULTS: Synergy was confirmed against both epimastigotes and amastigotes of the parasite. Edelfosine or ketoconazole alone induced morphological alterations in the plasma membrane and reservosomes of the parasites, while in combination, they also led to severe mitochondrial damage, formation of autophagic structures and multinucleation. Scanning electron microscopy confirmed the effect at the plasma membrane and also revealed alterations in the shape of the parasites. CONCLUSIONS: Our results describe the synergic anti-proliferative effect of LPAs and ketoconazole against epimastigotes and intracellular amastigotes and suggest that in epimastigotes, plasma membrane, reservosomes and mitochondria are targets of these drugs, possibly by interference with lipid metabolism.


Subject(s)
Ketoconazole/pharmacology , Lysophospholipids/pharmacology , Phospholipid Ethers/pharmacology , Phosphorylcholine/analogs & derivatives , Phosphorylcholine/pharmacology , Trypanocidal Agents/pharmacology , Trypanosoma cruzi/growth & development , Animals , Chlorocebus aethiops , Drug Synergism , Drug Therapy, Combination , Ergosterol/antagonists & inhibitors , Ergosterol/biosynthesis , Lysophospholipids/chemistry , Microscopy, Electron , Microscopy, Electron, Scanning , Parasitic Sensitivity Tests/methods , Trypanosoma cruzi/drug effects , Trypanosoma cruzi/ultrastructure , Vero Cells
14.
Antimicrob Agents Chemother ; 49(4): 1556-60, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15793138

ABSTRACT

We carried out a comparative study of benznidazole and TAK-187, a long-lasting ergosterol biosynthesis inhibitor, with a murine model of Chagas' disease. The results indicated that TAK-187 was more effective than benznidazole in preventing Trypanosoma cruzi-induced cardiac damage in experimental animals.


Subject(s)
Chagas Cardiomyopathy/prevention & control , Chagas Disease/drug therapy , Ergosterol/antagonists & inhibitors , Nitroimidazoles/therapeutic use , Triazoles/therapeutic use , Trypanocidal Agents/therapeutic use , Acute Disease , Animals , Chagas Disease/parasitology , Disease Models, Animal , Ergosterol/biosynthesis , Male , Mice , Trypanosoma cruzi/drug effects , Trypanosoma cruzi/pathogenicity
15.
Rev. méd. IMSS ; 33(5): 509-15, sept.-oct. 1995. ilus, tab
Article in Spanish | LILACS | ID: lil-174190

ABSTRACT

Se revisaron las caracteristicas farmacológicas del grupo de los imidazoles: ketoconazol, itraconazol y fluconazol y se compararon sus propiedades, interacciones, efectos secundarios e indicaciones. Se considera que este grupo de medicamentos dada su eficacia, seguridad y facilidad de administración, representan una buena alternativa en el manejo de las micosis profundas y sistémicas


Subject(s)
Azoles/administration & dosage , Triazoles/therapeutic use , Ergosterol/antagonists & inhibitors , Imidazoles/therapeutic use , Mycoses/therapy
16.
J Eukaryot Microbiol ; 42(4): 337-46, 1995.
Article in English | MEDLINE | ID: mdl-7620457

ABSTRACT

The antiproliferative effects and ultrastructural alterations induced in vitro by two antifungal compounds, the azole ketoconazole and the allylamine terbinafine on Leishmania amazonensis are reported. Promastigotes treatment with ketoconazole and terbinafine induced growth arrest and cell lysis in 72 hours. Combination of the two agents produced additive effects on promastigote axenic growth and synergistic effects on intracellular amastigote proliferation. The amastigotes, either axenically grown or infecting murine macrophages, were about 100-fold more sensitive to the drugs. These compounds induced the appearance of large multivesicular bodies, especially after ketoconazole treatment, increased amount of lipid inclusions as well as numerous, polymorphic volutin granules, particularly in terbinafine-treated cells. Multivesicular bodies were observed in close apposition with organelles such as mitochondria, which also showed alterations in the distribution and appearance of cristae, and the formation of paracrystalline arrays within the matrix. Some cells presented large portions of cytoplasm wrapped by endoplasmic reticulum and many parasites also presented myelin-like endoplasmic reticulum profiles. Such alterations together with the strong acid phosphatase activity observed in the multivesicular bodies and volutin granules may indicate the existence of an unusual autophagic process in cells treated with ergosterol biosynthesis inhibitors.


Subject(s)
Antifungal Agents/pharmacology , Antiprotozoal Agents/pharmacology , Ketoconazole/pharmacology , Leishmania mexicana/drug effects , Leishmaniasis, Cutaneous/parasitology , Naphthalenes/pharmacology , Acid Phosphatase/analysis , Animals , Drug Interactions , Ergosterol/antagonists & inhibitors , Ergosterol/biosynthesis , Host-Parasite Interactions/drug effects , Humans , Leishmania mexicana/physiology , Macrophages, Peritoneal/parasitology , Mice , Microscopy, Electron , Organelles/drug effects , Organelles/ultrastructure , Reproduction , Terbinafine
17.
Mycopathologia ; 74(2): 113-8, 1981 May 08.
Article in English | MEDLINE | ID: mdl-6264302

ABSTRACT

The ultrastructural changes produced by ketoconazole in the yeast-phase of H. capsulatum and P. brasiliensis were studied by means of scanning and transmission electron microscopy. The observed alterations on both fungi were very similar to those induced by the same drug on the ultrastructure of C. albicans. These alterations include surface changes, abnormal membrane proliferation, fatty degeneration of the cytoplasm and lysis of the subcellular organelles. P. brasiliensis seems to be more sensitive to ketoconazole than H. capsulatum, since the necrosis of most of the cells was obtained in the former at a concentration of 0.1 microgram/ml and in the latter at 1 microgram/ml.


Subject(s)
Fungi/drug effects , Histoplasma/drug effects , Imidazoles/pharmacology , Paracoccidioides/drug effects , Piperazines/pharmacology , Cell Membrane/drug effects , Cytoplasm/drug effects , Ergosterol/antagonists & inhibitors , Histoplasma/ultrastructure , Ketoconazole , Microscopy, Electron , Morphogenesis , Paracoccidioides/ultrastructure , Phospholipids/antagonists & inhibitors , Triglycerides/antagonists & inhibitors
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