Isabel Mayer de Andrade - Academia.edu (original) (raw)

Papers by Isabel Mayer de Andrade

Mice were inoculated with 5,000 T. cruzi Y strain ... more Mice were inoculated with 5,000 T. cruzi Y strain trypomastigotes by the intraperitoneal route and treated with daily doses 50, 75 and 100 mg/kg of bodyweight (mg/kg) of benznidazole (Bz) or itraconazole (Itz) alone or in combination for 20 consecutive days. (a) Maximum number of trypomastigotes detected in the peripheral blood of treated mice up to 30 days post-treatment. (b) IgG antibodies in treated mice by ELISA up to 30 days post-treatment. The results are shown as the reactivity index value, which was obtained by dividing the absorption value (O.D. value) of each serum sample by the mean value of the differential control uninfected sample. (-) negative results in fresh blood examination and PCR assay, (+) positive results in fresh blood examination and/or PCR assay, and & significant difference relative to benznidazole treatment administered alone at the same dose; ★ significant relative to itraconazole treatment administered alone at the same dose.</p

Mice were inoculated with 5000 trypomastigotes of VL-10 strain by intraperitoneal route ... more Mice were inoculated with 5000 trypomastigotes of VL-10 strain by intraperitoneal route and treated with fexinidazole 300 mg/kg of body weight (mpk), or benznidazole 100 mpk for 20 days. For controls, infected and untreated (IC) and uninfected (NIC) groups were also evaluated. A. IgG antibodies in mice treated with fexinidazole or benznidazole, compared with IC control group, 6 months post-treatment. B. Myocardial inflammatory cell count in cardiac tissue of mice infected with VL-10 T. cruzi strain, 6 months post-treatment. C. Hematoxilin-eosin stained slides. −Fex = mice with parasite negativity in fresh blood examination, blood culture, and PCR assay; +Fex or +Bz = mice positive of parasites in fresh blood examination, blood culture, and PCR assay: NIC = non-infected control; IC = infected and untreated control. * Significant difference compared to NIC; # significant difference compared to IC.</p

Maximum number of trypomastigotes detected in the peripheral blood of mice infected with... more Maximum number of trypomastigotes detected in the peripheral blood of mice infected with Trypanosoma cruzi Y strain and treated with daily doses 50, 75 or 100 mg/kg bodyweight (mg/kg) of benznidazole (Bz) or itraconazole (Itz) for 20 consecutive days and those in the infected control group (IC). Insert indicates Pearson correlation analysis between drug dose and parasitemia levels.</p

1Swiss female (n = 6) weight 20 to 24 g were inoculated with 5×103</sup&gt... more 1Swiss female (n = 6) weight 20 to 24 g were inoculated with 5×103 trypomastigotes (Ystrain).Treatment was started at 4th day after inoculation followed by 7 daily doses and the drugs were administered orally.*Significant difference in relation to benznidazole monotherapy treatment at same dose.ND – Not detected.</p

1Swiss female (n = 10) weight 20 to 24 g were inoculated with 5×103</sup&g... more 1Swiss female (n = 10) weight 20 to 24 g were inoculated with 5×103 trypomastigotes (Y strain).Treatment was initiated at 4th day after inoculation followed by 10 or 20 daily doses and it was being orally administered.2FBE – fresh blood examination performed before and after cyclophosphamide immunossupression.3PCR assay was performed in the 1st and 6th month after treatment.4mpk – milligrams/kilogram/day.5All mice died before 30 days of infection.6All mice had positive results in fresh blood examination.</p

1Swiss female (n = 10) weight 20 to 24 g were inoculated with 5×103</sup&g... more 1Swiss female (n = 10) weight 20 to 24 g were inoculated with 5×103 trypomastigotes (VL-10 strain).Treatment was initiated at 7th day after inoculation followed by 20 days and the drugs were administered orally. Benznidazole was given once daily and posaconazole administered twice a day (b.i.d.).2FBE – fresh blood examination performed before and after cyclophosphamide immunosuppression.3PCR assay was performed in the 1st and 6th month after treatment.</p

Maximum number of trypomastigote forms detected in the peripheral blood of mice infected... more Maximum number of trypomastigote forms detected in the peripheral blood of mice infected with Trypanosoma cruzi VL-10 strain and treated with 100 mg/kg of bodyweight (mpk) of benznidazole (Bz) or 40 mpk of posaconazole (Ps) and with Bz plus Ps combination at the following dosages: 50 or 100 mpk of Bz in combination with 10 or 20 mpk of Ps for 20 consecutive days. Benznidazole was given daily and posaconazole twice a day (b.i.d.). IC – infected and untreated animals. a, b, c - different letters indicate significant differences, and the same letters indicates similar values among parasitemia levels.</p

Chemical structure of fexinidazole and benznidazole.</p

The aim of this study was to assess the anti-Trypanosoma cruzi activity of nitroimidazoles compou... more The aim of this study was to assess the anti-Trypanosoma cruzi activity of nitroimidazoles compounds using three sequential in vivo assays: (i) evaluation of the efficacy of a single dose of each compound to reduce parasitemia and mortality; (ii) determination of the effective dose of each new compound using a rapid treatment for 7 days; (iii) assessment of the efficacy of each compound to cure mice infected with the Y T. cruzi strain, which is moderately resistant to Benznidazole (Bz) and (iv) evaluate cure on T.cruzi resistant model of infection (VL-10 and Colobian strain). Experimental animals were infected with 5x10 3 blood trypomastigotes and treated with Fexinidazole (Fex), DNDi-IM2, DNDi-IM3, DNDi-IM4 and the reference drug, Bz. Our results showed that, for all evaluated nitroimidazoles, a single dose of 500 mpk (mg/kg) was efficient to suppress or reduce the parasite load and mortality of infected mice, at levels better, similar; or lower than Bz-treatment for Fex and DNDi-IM3, DNDi-IM2 or DNDi-IM4, respectively. In the second treatment scheme a relationship between the dose and the therapeutic response was observed. Usually, the treatment with 300mpk/day was able to induce higher (Fex and DNDi-IM3) similar (DNDi-IM2) or lower (DNDi-IM4) levels of parasite clearance, when compared with Bz treatment. Additionally, treatment with 300 mpk of the DNDi-IM4 for 20 days did not induce parasitological cure. The DNDi-IM3-treatment was able to induce parasitological cure in 33.3% of mice, being the Bz-treatment induced 60.1% of parasitological cure. Differently, treatment with 300mpk of the Fex and DNDi-IM3 was able to induce parasitological cure in 80% and 100% of mice, respectively. Considering the high efficacy of Fex we were interested to assess the effect of Fex on mice infected with VL-10 and Colombian Bz resistant strains. The Fex-treatment of mice infected with these T. cruzi stocks during the acute phase of the infection induced to 89% and 78% of parasitological cure, while the Bz-treatment was not able to induce cure in animals infected with these stocks. The Fex induced 70% of cure in VL-10 infected mice, when treated in cronic infection. More important, we demonstrated that Fex treatment decrease the myocarditis in all VL-10 and Colombian infected animals, although parasite eradication could not be achieved in all treated animals. These data clearly show that Fex has high anti-T. cruzi activity and efficacy to cure these experimental infection models, and is more effective when compared to standardized Bz treatment at the doses tested. An overall analysis in our results indicated that all nitroimidazoles tested here presented activity against T. cruzi, but with individual differences in their potency.

Chemical Biology & Drug Design, 2014

This article is protected by copyright. All rights reserved. values ranging from 1.4 to 46 µM. No... more This article is protected by copyright. All rights reserved. values ranging from 1.4 to 46 µM. None of these compounds was toxic to a normal monkey kidney cell line (BGM), thus exhibiting good selectivity indexes, as high 351 for one compound (11).

Memórias do Instituto Oswaldo Cruz, 2014

Due to the recent advances of atovaquone, a naphthoquinone, through clinical trials as treatment ... more Due to the recent advances of atovaquone, a naphthoquinone, through clinical trials as treatment for malarial infection, 19 quinone derivatives with previously reported structures were also evaluated for blood schizonticide activity against the malaria parasite Plasmodium falciparum. These compounds include 2-hydroxy-3-methylamino naphthoquinones (2-9), lapachol (10), nor-lapachol (11), iso-lapachol (12), phthiocol (13) and phenazines (12-20). Their cytotoxicities were also evaluated against human hepatoma and normal monkey kidney cell lines. Compounds 2 and 5 showed the highest activity against P. falciparum chloroquine-resistant blood-stage parasites (clone W2), indicated by their low inhibitory concentration for 50% (IC 50) of parasite growth. The therapeutic potential of the active compounds was evaluated according to the selectivity index, which is a ratio of the cytotoxicity minimum lethal dose which eliminates 50% of cells and the in vitro IC 50. Naphthoquinones 2 and 5, with activities similar to the reference antimalarial chloroquine, were also active against malaria in mice and suppressed parasitaemia by more than 60% in contrast to compound 11 which was inactive. Based on their in vitro and in vivo activities, compounds 2 and 5 are considered promising molecules for antimalarial treatment and warrant further study.

Malaria Journal, 2014

Background: Several species of Aspidosperma (Apocynaceae) are used as treatments for human diseas... more Background: Several species of Aspidosperma (Apocynaceae) are used as treatments for human diseases in the tropics. Aspidosperma olivaceum, which is used to treat fevers in some regions of Brazil, contains the monoterpenoid indole alkaloids (MIAs) aspidoscarpine, uleine, apparicine, and N-methyl-tetrahydrolivacine. Using bio-guided fractionation and cytotoxicity testing in a human hepatoma cell line, several plant fractions and compounds purified from the bark and leaves of the plant were characterized for specific therapeutic activity (and selectivity index, SI) in vitro against the blood forms of Plasmodium falciparum. Methods: The activity of A. olivaceum extracts, fractions, and isolated compounds was evaluated against chloroquine (CQ)-resistant P. falciparum blood parasites by in vitro testing with radiolabelled [ 3 H]-hypoxanthine and a monoclonal anti-histidine-rich protein (HRPII) antibody. The cytotoxicity of these fractions and compounds was evaluated in a human hepatoma cell line using a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, and the SI was calculated as the ratio between the toxicity and activity. Two leaf fractions were tested in mice with Plasmodium berghei. Results: All six fractions from the bark and leaf extracts were active in vitro at low doses (IC 50 < 5.0 μg/mL) using the anti-HRPII test, and only two (the neutral and basic bark fractions) were toxic to a human cell line (HepG2). The most promising fractions were the crude leaf extract and its basic residue, which had SIs above 50. Among the four pure compounds evaluated, aspidoscarpine in the bark and leaf extracts showed the highest SI at 56; this compound, therefore, represents a possible anti-malarial drug that requires further study. The acidic leaf fraction administered by gavage to mice with blood-induced malaria was also active. Conclusion: Using a bio-monitoring approach, it was possible to attribute the anti-P. falciparum activity of A. olivaceum to aspidoscarpine and, to a lesser extent, N-methyl-tetrahydrolivacine; other isolated MIA molecules were active but had lower SIs due to their higher toxicities. These results stood in contrast to previous work in which the anti-malarial activity of other Aspidosperma species was attributed to uleine.

PLoS Neglected Tropical Diseases, 2013

Background: Current chemotherapy for Chagas disease is unsatisfactory due to its limited efficacy... more Background: Current chemotherapy for Chagas disease is unsatisfactory due to its limited efficacy, particularly in the chronic phase, with frequent side effects that can lead to treatment discontinuation. Combined therapy is envisioned as an ideal approach since it may improve treatment efficacy whilst decreasing toxicity and the likelihood of resistance development. We evaluated the efficacy of posaconazole in combination with benznidazole on Trypanosoma cruzi infection in vivo. Methods and Findings: Benznidazole and posaconazole were administered individually or in combination in an experimental acute murine infection model. Using a rapid treatment protocol for 7 days, the combined treatments were more efficacious in reducing parasitemia levels than the drugs given alone, with the effects most evident in combinations of sub-optimal doses of the drugs. Subsequently, the curative action of these drug combinations was investigated, using the same infection model and 25, 50, 75 or 100 mg/kg/day (mpk) of benznidazole in combination with 5, 10 or 20 mpk of posaconazole, given alone or concomitantly for 20 days. The effects of the combination treatments on parasitological cures were higher than the sum of such effects when the drugs were administered separately at the same doses, indicating synergistic activity. Finally, sequential therapy experiments were carried out with benznidazole or posaconazole over a short interval (10 days), followed by the second drug administered for the same period of time. It was found that the sequence of benznidazole (100 mpk) followed by posaconazole (20 mpk) provided cure rates comparable to those obtained with the full (20 days) treatments with either drug alone, and no cure was observed for the short treatments with drugs given alone. Conclusions: Our data demonstrate the importance of investigating the potential beneficial effects of combination treatments with marketed compounds, and showed that combinations of benznidazole with posaconazole have a positive interaction in murine models of Chagas disease.

Memórias do Instituto …, 2008

PLoS Neglected Tropical Diseases, 2012

PLOS ONE, 2015

The nitroheterocyclic drugs nifurtimox and benznidazole are first-line drugs available to treat C... more The nitroheterocyclic drugs nifurtimox and benznidazole are first-line drugs available to treat Chagas disease; however, they have limitations, including long treatment courses and toxicity. Strategies to overcome these limitations include the identification of new drugs with specific target profiles, re-dosing regimens for the current drugs, drug repositioning and combination therapy. In this work, we evaluated combination therapy as an approach for optimization of the current therapeutic regimen for Chagas disease. The curative action of benznidazole/itraconazole combinations was explored in an established infection of the mice model with the T. cruzi Y strain. The activities of the benznidazole/itraconazole combinations were compared with the results from those receiving the same dosage of each individual drug. The administration of benznidazole/itraconazole in combination eliminated parasites from the blood more efficiently than each drug alone. Here, there was a significant reduction of the number of treatment days (number of doses) necessary to induce parasitemia suppression with the benznidazole/itraconazole combination, as compared to each compound administered alone. These results clearly indicate the enhanced effects of these drugs in combination, particularly at the dose of 75 mg/kg, as the effects observed with the drug combinations were four times more effective than those of each drug used alone. Moreover, benznidazole/itraconazole treatment was shown to prevent or decrease the typical lesions associated with chronic experimental Chagas disease, as illustrated by similar levels of inflammatory cells and fibrosis in the cardiac muscle tissue of healthy and treated mice. These results emphasize the importance of exploring the potential of combination treatments with currently available compounds to specifically treat Chagas disease.

Background: New safe and effective treatments for Chagas disease (CD) are urgently needed. Curren... more Background: New safe and effective treatments for Chagas disease (CD) are urgently needed. Current chemotherapy options for CD have significant limitations, including failure to uniformly achieve parasitological cure or prevent the chronic phase of CD, and safety and tolerability concerns. Fexinidazole, a 2-subsituted 5-nitroimidazole drug candidate rediscovered following extensive compound mining by the Drugs for Neglected Diseases initiative and currently in Phase I clinical study for the treatment of human African trypanosomiasis, was evaluated in experimental models of acute and chronic CD caused by different strains of Trypanosoma cruzi. Methods and Findings: We investigated the in vivo activity of fexinidazole against T. cruzi, using mice as hosts. The T. cruzi strains used in the study were previously characterized in murine models as susceptible (CL strain), partially resistant (Y strain), and resistant (Colombian and VL-10 strains) to the drugs currently in clinical use, be...

European Journal of Pharmaceutics and Biopharmaceutics Official Journal of Arbeitsgemeinschaft Fur Pharmazeutische Verfahrenstechnik E V, Mar 1, 2011

Benznidazole (BNZ) is traditionally used to treat Chagas disease. Despite its common use, BNZ has... more Benznidazole (BNZ) is traditionally used to treat Chagas disease. Despite its common use, BNZ has a poor water solubility and a variable bioavailability. The purpose of this study was to prepare BNZ microcrystals by solvent change precipitation and to study the effects of BNZ micronisation on therapeutic efficiency using a murine model of Chagas disease. The solvent change precipitation procedure was optimised in order to obtain stable and homogeneous particles with a small particle size, high yield and fast dissolution rate. The thermal and crystallographic analysis showed no polymorphic change in the microcrystals, and microscopy confirmed a significant reduction in particle size. A marked improvement in the drug dissolution rate was observed for micronised BNZ particles and BNZ tablets in comparison with untreated BNZ and commercial Rochagan. In vivo studies showed a significant increase in the therapeutic efficacy of the BNZ microparticles, corroborating the dissolution results.

1Swiss female (n = 10) weight 20 to 24 g were inoculated with 5×103</sup&g... more 1Swiss female (n = 10) weight 20 to 24 g were inoculated with 5×103 trypomastigotes (VL-10 strain).Treatment was initiated at 7th day after inoculation followed by 20 days and the drugs were administered orally. Benznidazole was given once daily and posaconazole administered twice a day (b.i.d.).2FBE – fresh blood examination performed before and after cyclophosphamide immunosuppression.3PCR assay was performed in the 1st and 6th month after treatment.</p