Navegando por Autor "Richard, Sylvain"
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Item Avaliação in vivo da eficácia antimalárica, toxicidade cardiovascular e neurocomportamental do arteméter por via oral veiculado em nanocápsulas.(2017) Souza, Ana Carolina Moreira; Guimarães, Andrea Grabe; Mosqueira, Vanessa Carla Furtado; Richard, Sylvain; Guimarães, Andrea Grabe; Fagundes, Elaine Maria de Souza; Leite, Elaine Amaral; Bahia, Maria Terezinha; Isoldi, Mauro CésarO arteméter (ATM) é um antimalárico utilizado clinicamente em combinação (ATC) com outros antimaláricos (WHO, 2016). Apresenta meia vida plasmática curta, baixa biodisponibilidade por via oral e toxicidade cardiovascular e neurológica, entre outros efeitos adversos. Nanocápsulas de poly-ε-caprolactona veiculando ATM (ATM-NC) foram desenvolvidas e caracterizadas anteriormente. O objetivo deste trabalho foi avaliar a eficácia antimalárica in vivo e os efeitos cardiovasculares e neurocomportamentais de ATM-NC administrado por via oral em comparação ao ATM em sua forma livre. Foram utilizados camundongos C57BL6 fêmeas previamente infectados por Plasmodium berghei para a avaliação da eficácia antimalárica e machos para a avaliação dos efeitos cardiovasculares e neurocomportamentais. Os animais foram tratados por via oral, duas vezes ao dia por 4 dias com veículo (sorbitol/carboximetilcelulose) ou NC branca, ATM livre ou ATM-NC, nas doses de 40, 80 e 120 mg/kg. ATM-NC (120 mg/kg) aboliram a parasitemia e promoveram a sobrevida de 100 %. Para avaliar a cardiotoxicidade foram realizados: 1) eletrocardiograma (ECG) na derivação periférica II antes e após o tratamento em camundongos anestesiados, não infectados e infectados. O ATM livre induziu cardiotoxicidade evidenciado pelo prolongamento dos intervalos QT e QTc. Para a maior dose estudada (120ºmg/kg), em camundongos não infectados, ATM-NC impediu estes prolongamentos em 34 % e 30 %, respectivamente, comparado ao ATM livre. Nos camundongos infectados, ATM-NC também reduziu o prolongamento dos intervalos QT e QTc em 28 % e 27 %, respectivamente. 2) Ecocardiograma (ECO) foi realizado em camundongos não infectados e tratados com ATM livre e ATM-NC na dose de 120 mg/kg. Para este estudo não foram encontradas diferenças significativas entre os grupos avaliados. Os cardiomiócitos de camundongos previamente tratados com a dose de 120 mg/kg foram isolados e avaliados in vitro 3) sob estimulação em campo (1 Hz) em sistema Ionoptix para o transiente de Ca2+ e contratilidade do sarcômero, 4) em sistema patch-clamp para o potencial de ação (PA) e a corrente nos canais de Ca2+. O ATM livre reduziu o transiente de Ca2+ em 41 %, o Ca2+ diastólico em 12 % e a porcentagem de encurtamento do sarcômero de 4,6 % (controle) para 3,1 %. Além disso, o ATM livre causou o prolongamento do PA comparado ao veículo (350,0 ± 49,3 ms e 137,7 ± 20,5 ms, respectivamente). 5) Cardiomiócitos de camundongos não tratados foram isolados e incubados com ATM livre nas concentrações 0,1; 1 e 10 µM. ATM livre 10 µM reproduziu os efeitos sobre Ca2+ observados nos cardiomióciotos dos camundongos tratados, assim indicando efeitos cardiotóxicos. Por outro lado, ATM-NC não causou nenhuma alteração significativa em nenhum dos parâmetros avaliados. A avaliação da neurotoxicidade foi realizada em camundongos não infectados e infectados. Para os camundongos não infectados o ATM livre (120 mg/kg) reduziu significativamente a capacidade de exploração nos braços abertos do labirinto em cruz elevado, indicando transtorno neurocomportamental como a ansiedade. Para animais infectados o tratamento com ATM livre (120 mg/kg) desencadeou comportamentos similares a ansiedade e diminui a capacidade locomotora dos camundongos, pois reduziu em 65 % e 67 % a capacidade exploratória dos braços abertos e fechados do labirinto em cruz elevado. ATM-NC impediu a manifestação dos efeitos neurocomportamentais em camundongos não infectados e reduziu os efeitos sobre os camundongos infectados. Concluímos que o ATM em NC apresentou eficácia por via oral e que NC são capazes de impedir ou minimizar os efeitos cardiotóxicos e neurocomportamentais causados pelo ATM em sua forma livre.Item Biodegradable polymeric nanocapsules prevent cardiotoxicity of anti-trypanosomal lychnopholide.(2017) Branquinho, Renata Tupinambá; Roy, Jérôme; Farah, Charlotte; Garcia, Giani Martins; Aimond, Franck; Guennec, Jean Yves Le; Guimarães, Dênia Antunes Saúde; Guimarães, Andrea Grabe; Mosqueira, Vanessa Carla Furtado; Lana, Marta de; Richard, SylvainChagas disease is a neglected parasitic disease caused by the protozoan Trypanosoma cruzi. New antitrypanosomal options are desirable to prevent complications, including a high rate of cardiomyopathy. Recently, a natural substance, lychnopholide, has shown therapeutic potential, especially when encapsulated in biodegradable polymeric nanocapsules. However, little is known regarding possible adverse effects of lychnopholide. Here we show that repeated-dose intravenous administration of free lychnopholide (2.0 mg/kg/day) for 20 days caused cardiopathy and mortality in healthy C57BL/6 mice. Echocardiography revealed concentric left ventricular hypertrophy with preserved ejection fraction, diastolic dysfunction and chamber dilatation at end-stage. Single cardiomyocytes presented altered contractility and Ca2+ handling, with spontaneous Ca2+ waves in diastole. Acute in vitro lychnopholide application on cardiomyocytes from healthy mice also induced Ca2+ handling alterations with abnormal RyR2-mediated diastolic Ca2+ release. Strikingly, the encapsulation of lychnopholide prevented the cardiac alterations induced in vivo by the free form repeated doses. Nanocapsules alone had no adverse cardiac effects. Altogether, our data establish lychnopholide presented in nanocapsule form more firmly as a promising new drug candidate to cure Chagas disease with minimal cardiotoxicity. Our study also highlights the potential of nanotechnology not only to improve the efficacy of a drug but also to protect against its adverse effects.Item Mechanisms of artemether toxicity on single cardiomyocytes and protective effect of nanoencapsulation.(2020) Souza, Ana Carolina Moreira; Guimarães, Andrea Grabe; Cruz, Jader dos Santos; Miranda, Artur Santos; Farah, Charlotte; Oliveira, Liliam Teixeira; Lucas, Alexandre; Aimond, Franck; Sicard, Pierre; Mosqueira, Vanessa Carla Furtado; Richard, SylvainBackground and Purpose: The artemisinin derivative, artemether, has antimalarial activity with potential neurotoxic and cardiotoxic effects. Artemether in nanocapsules (NC-ATM) is more efficient than free artemether for reducing parasitaemia and increasing survival of Plasmodium berghei-infected mice. NCs also prevent prolongation of the QT interval of the ECG. Here, we assessed cellular cardiotoxicity of artemether and how this toxicity was prevented by nanoencapsulation. Experimental Approach: Mice were treated with NC-ATM orally (120 mg kg−1 twice daily) for 4 days. Other mice received free artemether, blank NCs, and vehicle for comparison. We measured single-cell contraction, intracellular Ca2+ transient using fluorescent Indo-1AM Ca2+ dye, and electrical activity using the patch-clamp tech nique in freshly isolated left ventricular myocytes. The acute effect of free artemether was also tested on cardiomyocytes of untreated animals. Key Results: Artemether prolonged action potentials (AP) upon acute exposure (at 0.1, 1, and 10 μM) of cardiomyocytes from untreated mice or after in vivo treatment. This prolongation was unrelated to blockade of K+ currents, increased Ca2 + currents or promotion of a sustained Na+ current. AP lengthening was abolished by the NCX inhibitor SEA-0400. Artemether promoted irregular Ca2+ transients during pacing and spontaneous Ca2+ events during resting periods. NC-ATM prevented all effects. Blank NCs had no effects compared with vehicle. Conclusion and Implications: Artemether induced NCX-dependent AP lengthening (explaining QTc prolongation) and disrupted Ca2+ handling, both effects increasing pro-arrhythmogenic risks. NCs prevented these adverse effects, providing a safe alternative to the use of artemether alone, especially to treat malaria.Item Polyester nanocapsules for intravenous delivery of artemether : formulation development, antimalarial efficacy, and cardioprotective effects in vivo.(2022) Diniz, Alessandra Teixeira Vidal; Guimarães, Homero Nogueira; Garcia, Giani Martins; Braga, Érika Martins; Richard, Sylvain; Guimarães, Andrea Grabe; Mosqueira, Vanessa Carla FurtadoArtemether (ATM) is an effective antimalarial drug that also has a short half-life in the blood. Furthermore, ATM is also cardiotoxic and is associated with pro-arrhythmogenic risks. We aimed to develop a delivery system enabling the prolonged release of ATM into the blood coupled with reduced cardiotoxicity. To achieve this, we prepared polymeric nanocapsules (NCs) from different biodegradable polyesters, namely poly(D,L-lactide) (PLA), poly-ε-caprolactone (PCL), and surface-modified NCs, using a monomethoxi-polyethylene glycol-block-poly(D,L-lactide) (PEG5kDa- PLA45kDa) polymer. Using this approach, we were able to encapsulate high yields of ATM (>85%, 0–4 mg/mL) within the oily core of the NCs. The PCL-NCs exhibited the highest percentage of ATM loading as well as a slow release rate. Atomic force microscopy showed nanometric and spherical particles with a narrow size dispersion. We used the PCL NCs loaded with ATM for biological evaluation following IV administration. As with free-ATM, the ATM-PCL-NCs formulation exhibited potent antimalarial efficacy using either the “Four-day test” protocol (ATM total at the end of the 4 daily doses: 40 and 80 mg/kg) in Swiss mice infected with P. berghei or a single low dose (20 mg/kg) of ATM in mice with higher parasitemia (15%). In healthy rats, IV administration of single doses of free-ATM (40 or 80 mg/kg) prolonged cardiac QT and QTc intervals and induced both bradycardia and hypotension. Repeated IV administration of free-ATM (four IV doses at 20 mg/kg every 12 h for 48 h) also prolonged the QT and QTc intervals but, paradoxically, induced tachycardia and hypertension. Remarkably, the incorporation of ATM in ATM-PCL-NCs reduced all adverse effects. In conclusion, the encapsulation of ATM in biodegradable polyester NCs reduces its cardiovascular toxicity without affecting its antimalarial efficacy.Item Polymeric nanocapsules prevent oxidation of core-loaded molecules : evidence based on the effects of docosahexaenoic acid and neuroprostane on breast cancer cells proliferation.(2015) Roy, Jérôme; Oliveira, Liliam Teixeira; Oger, Camille; Galano, Jean Marie; Poncé, Valerie Bultel; Richard, Sylvain; Guimarães, Andrea Grabe; Vilela, José Mário Carneiro; Andrade, Margareth Spangler; Durand, Thierry; Besson, Pierre; Mosqueira, Vanessa Carla Furtado; Guennec, Jean-Yves LeBackground: Nanocapsules, as a delivery system, are able to target drugs and other biologically sensitive molecules to specific cells or organs. This system has been intensively investigated as a way to protect bioactives drugs from inactivation upon interaction with the body and to ensure the release to the target. However, the mechanism of improved activity of the nanoencapsulated molecules is far from being understood at the cellular and subcellular levels. Epidemiological studies suggest that dietary polyunsaturated fatty acids (PUFA) can reduce the morbidity and mortality from breast cancer. This influence could be modulated by the oxidative status of the diet and it has been suggested that the anti-proliferative properties of docosahexaenoic acid (DHA) are enhanced by pro-oxidant agents. Methods: The effect of encapsulation of PUFA on breast cancer cell proliferation in different oxidative medium was evaluated in vitro. We compared the proliferation of the human breast cancer cell line MDA-MB-231 and of the non-cancer human mammary epithelial cell line MCF 10A in different experimental conditions. Results: DHA possessed anti-proliferative properties that were prevented by alpha-tocopherol (an antioxidant) and enhanced by the pro-oxidant hydrogen peroxide that confirms that DHA has to be oxidized to exert its anti-proliferative properties. We also evaluated the anti-proliferative effects of the 4(RS)-4-F4t-neuroprostane, a bioactive, non-enzymatic oxygenated metabolite of DHA known to play a major role in the prevention of cardiovascular diseases. DHA-loaded nanocapsules was less potent than non-encapsulated DHA while co-encapsulation of DHA with H2O2 maintained the inhibition of proliferation. The nanocapsules slightly improves the anti-proliferative effect in the case of 4(RS)-4-F4t-neuroprostane that is more hydrophilic than DHA. Conclusion: Overall, our findings suggest that the sensitivity of tumor cell lines to DHA involves oxidized metabolites. They also indicate that neuroprostane is a metabolite participating in the growth reducing effect of DHA, but it is not the sole. These results also suggest that NC seek to enhance the stability against degradation, enhance cellular availability, and control the release of bioactive fatty acids following their lipophilicities.Item Reduced cardiotoxicity and increased oral efficacy of artemether polymeric nanocapsules in Plasmodium berghei-infected mice.(2018) Souza, Ana Carolina Moreira; Mosqueira, Vanessa Carla Furtado; Silveira, Ana Paula Amariz; Antunes, Lidiane Rodrigues; Richard, Sylvain; Guimarães, Homero Nogueira; Guimarães, Andrea GrabeArtemether (ATM) cardiotoxicity, its short half-life and low oral bioavailability are the major limiting factors for its use to treat malaria. The purposes of this work were to study free-ATM and ATM-loaded poly-ε-caprolactone nanocapules (ATM-NC) cardiotoxicity and oral efficacy on Plasmodium berghei-infected mice. ATM-NC was obtained by interfacial polymer deposition and ATM was associated with polymeric NC oily core. For cardiotoxicity evaluation, male black C57BL6 uninfected or P. berghei-infected mice received, by oral route twice daily/4 days, vehicle (sorbitol/carboxymethylcellulose), blank-NC, free-ATM or ATMNC at doses 40, 80 or 120 mg kg−1 . Electrocardiogram (ECG) lead II signal was obtained before and after treatment. For ATM efficacy evaluation, female P. berghei-infected mice were treated the same way. ATM-NC improved antimalarial in vivo efficacy and reduced mice mortality. Free-ATM induced significantly QT and QTc intervals prolongation. ATMNC (120 mg kg−1 ) given to uninfected mice reduced QT and QTc intervals prolongation 34 and 30%, respectively, compared with free-ATM. ATM-NC given to infected mice also reduced QT and QTc intervals prolongation, 28 and 27%, respectively. For the first time, the study showed a nanocarrier reducing cardiotoxicity of ATM given by oral route and it was more effective against P. berghei than free-ATM as monotherapy.