2 research outputs found
Advances in nanocarriers as drug delivery systems in Chagas disease
Chagas disease is one of the most important public health problems in Latin America due to its high mortality and morbidity levels. There is no effective treatment for this disease since drugs are usually toxic with low bioavailability. Serious efforts to achieve disease control and eventual eradication have been unsuccessful to date, emphasizing the need for rapid diagnosis, drug development, and a reliable vaccine. Novel systems for drug and vaccine administration based on nanocarriers represent a promising avenue for Chagas disease treatment. Nanoparticulate systems can reduce toxicity, and increase the efficacy and bioavailability of active compounds by prolonging release, and therefore improve the therapeutic index. Moreover, nanoparticles are able to interact with the host’s immune system, modulating the immune response to favour the elimination of pathogenic microorganisms. In addition, new advances in diagnostic assays, such as nanobiosensors, are beneficial in that they enable precise identification of the pathogen. In this review, we provide an overview of the strategies and nanocarrier-based delivery systems for antichagasic agents, such as liposomes, micelles, nanoemulsions, polymeric and non-polymeric nanoparticles. We address recent progress, with a particular focus on the advances of nanovaccines and nanodiagnostics, exploring new perspectives on Chagas disease treatment
Produção, caracterização e avaliação citotóxica de membranas lipídicas miméticas para a liberação do tripanocida N, N’-Squaramide 17 na linhagem CL-Brener de Trypanosoma cruzi
Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Pós-Graduação em Nanociência e Nanobiotecnologia, 2018.A doença de Chagas afeta cerca de 25 milhões de pessoas no mundo e é causada por
Trypanosoma cruzi (T.c.). Atualmente, os dois únicos medicamentos disponíveis utilizados para
o tratamento desta enfermidade - benzonidazol (BZ) e nifurtimox - provocam efeitos adversos no
paciente. Com isso, novos fármacos têm sido estudados a fim de se encontrar estratégias
terapêuticas mais eficientes, como o N, N'-Squaramide 17 (S) um composto com excelente
potencial terapêutico. Por meio da nanotecnologia, é possível aumentar a eficiência de fármacos
e reduzir a sua toxicidade, graças às propriedades de nanoestruturas que podem favorecer a
liberação sustentada, utilizando doses baixas do fármaco e aumentando sua concentração nos
tecidos alvos. O objetivo deste trabalho foi desenvolver membranas lipídicas miméticas, a partir
de lipídios das membranas celulares de macrófagos (linhagem RAW 264.7) e encapsular o S
nesta nanoestrutura, visando melhorar sua eficácia tripanocida sobre linhagem CL-Brener.
Assim, foram desenvolvidas e caracterizadas as nanoestruturas: (1) membrana mimética lipídica
contendo S (MLS); (2) membrana mimética lipídica vazia (MLV) e (3) N, N’-Squaramide 17
extrusado (SE). Adicionalmente, foram avaliados as características físico-químicas e os efeitos
citotóxico e tripanocida destas nanoestruturas. O diâmetro hidrodinâmico (dH) médio e potencial
zeta das nanoestruturas foram, respectivamente, de 196.5 ± 11 nm/– 61.43 ± 2.3 mV para MLS;
203.1 ± 8.5 nm/– 12.9 ± 1,2 mV para MLV e 713.9 ± 112.6 nm/– 45.3 ± 7.45 mV para SE. Notou-
se que o dH da MLS reduziu em torno de 70 nm após 10 dias de armazenamento, indicando
possível liberação do S. A encapsulação de S nas membranas miméticas foi comprovada
empregando a análise de espectroscopia vibracional na região do infravermelho (IR) e notou-se
que a nanoestrutura MLS apresentou bandas em 1788 cm-1 e 1674 cm-1 características dos
grupos carbonilas existentes em S. Em relação aos efeitos citotóxicos, após 72h de tratamento,
observou-se que a MLV apresentou excelente potencial como veículo para entrega de fármacos
visto ter nenhuma citotoxicidade em células de mamíferos nas concentrações testados. Por outro
lado, MLS, nanoestrutura contendo o S, foi ativo contra epimastigotas (IC50 de 15,9 ± 4,8 μM) e
amastigotas intracelulares (IC50 de 24,99 ±4,8 μM). Ademais, induziu baixa citotoxicidade
com IC50 de 626.7 ± 4.7 em células VERO e de 1974 ± 6 em RAW 264.7. A partir destes dados,
determinou-se o índice de seletividade (SI) e observou-se que MLS induziu atividade tripanocida
superior ao BZ em 57 vezes quando foram avaliadas a forma epimastigota e 9 vezes maior em
amastigota, mostrando ter ação alvo específica. Nos ensaios de infecção celular, as células
VERO foram infectadas com tripomastigotas e posteriormente incubadas com a metade da
citotoxicidade (IC50/2): (313 μM) de MLS por 12 h e depois analisou-se sua atividade tripanocida
durante oito dias. Observou-se no 8o dia maior inibição na taxa de infecção de amastigotas (72
%) do que com o tratamento com BZ (51%) (6.84 μM). Ainda, o número de tripomastigotas
extracelulares foi reduzido em 81 % após tratamento com MLS enquanto que BZ reduziu em 54
%. MLS também induziu alterações estruturais nos parasitas como fissuras com diâmetro de
aproximadamente 200 nm na parte superior celular da epimastigota e em tripomastigota uma
diferenciação em amastigota. Desta forma, MLS apresentou promissora eficácia tripanocida.
Ademais, o fato da MLS ter induzido baixa citotoxicidade nas linhagens celular de mamíferos
(RAW 264.7 e VERO) e elevada atividade contra os parasitas demonstra sua toxicidade alvo-
específica, tornando, assim, estas nanoestruturas promissoras para aplicação no tratamento da
doença de Chagas.Chagas disease affects about 25 million people in the world and is caused by Trypanosoma cruzi
(T.c.). Currently, the only two drugs available for the its treatment - Benzonidazol (BZ) and
nifurtimox - cause adverse effects in the patient. With this, new drugs have been studied in order
to find more efficient therapeutic strategies, such as N, N'-Squaramide 17 (S), which represents
a compound with excellent therapeutic potential. By means of nanotechnology, it is possible to
improve the drug activity thanks to the properties of nanostructures that can promote sustained,
release using low doses of drug and increasing its concentration in tissues. The objective of this
work was to develop mimetic lipid membranes, from macrophage cell membrane lipids (lineage
RAW 264.7) and encapsulate the S in this nanostructure, thus improving its trypanocidal efficacy
on CL-Brener strain. Thus, nanostructures were developed and characterized: (1) mimetic lipid
membrane containing S (MLS); (2) empty lipid mimetic membrane (MLV) and (3) N, N'-
Squaramide 17 extruded (SE). Additionally, the physic-chemical characteristics and the cytotoxic
and trypanocidal effects of these nanostructures were evaluated. The mean hydrodynamic
diameter (dH) and zeta potential of the nanostructures were, respectively, 196.5 ± 11 nm / - 61.43
± 2.3 mV for MLS; 203.1 ± 8.5 nm / - 12.9 ± 1.2 mV for MLV and 713.9 ± 112.6 nm / - 45.3 ± 7.45
mV for SE. It was observed that the MLS dH reduced around 70 nm after 10 days of storage,
indicated possible release of S. The encapsulation of S in the mimetic membranes was verified
using the analysis of vibrational spectroscopy in the infrared (IR) region and It was observed that
the MLS nanostructure showed bands in 1788 cm-1 and 1674 cm-1 characteristics of the existing
carbonyl groups in S. In relation to the cytotoxic effects, after 72h of treatment, it was observed
that the MLV presented an excellent potential as vehicle for the delivery of drugs since there is
no cytotoxicity in the mammalian cells under the concentrations tested. On the other hand, MLS,
the nanostructure containing the S, was active against epimastigotes (IC50 of 15.9 ± 4.8 μM) and
intracellular amastigotes (IC50 of 24.99 ± 4.8 μM), in addition, induced low cytotoxicity with IC50 of
626.7 ± 4.7 in VERO cells and 1974 ± 6 in RAW 264.7, From these data, the selectivity index (SI)
was determined and it was observed that MLS induced trypanocidal activity superior to BZ in 57
times over epimastigota form and 9 times greater in amastigotas, showing a specific action. In
the cell infection assays, the VERO cells were infected with trypomastigotes, incubated with half
of the cytotoxicity IC50/2: (313 μM) of MLS for 12 h and then their trypanocidal activity was
analyzed for eight days. It was observed on the 8th day, there was a greater inhibition in the
infection rate of amastigotes (72%) than with the treatment with BZ (51%) (6.84 μM). In addition,
the number of extracellular trypomastigotes was reduced by 81% after treatment with MLS while
BZ reduced by 54%. MLS also induced structural changes in parasites such as fissures with a
diameter of approximately 200 nm in the upper cellular part of the epimastigote and in
tripomastigote showed a differentiation in amastigotes. In this way, MLS presented a promising
trypanocidal efficacy. In addition, the fact that MLS has induced low cytotoxicity in mammalian
cell lineages (RAW 264.7 and VERO) and high activity against the parasites demonstrates their
specific toxicity, thus making this nanostructure promising for its application in the treatment of
Chagas disease