Lychnopholide loaded in surface modified polylactide nanocapsules (LYC-PLA-PEG-NC) cure mice infected by Trypanosoma cruzi strain a prototype of resistance to benznidazole and nifurtimox: First insights of its mechanism of action.

Chagas disease (CD) remains neglected and causes high morbidity and mortality. The great difficulty is the lack of effective treatment. The current drugs cause side effects and have limited therapeutic efficacy in the chronic phase. This study aims to fulfil some gaps in studies of the natural substance lychnopholide nanoencapsulated LYC-PLA-PEG-NC (LYC-NC) and free (Free-LYC): the activity in epimastigotes and amastigotes to determine its selectivity index (SI), the therapeutic efficacy in mice infected with Colombian Trypanosoma cruzi strain and insight of the mechanism of LYC-NC action on T. cruzi. The SI was obtained by calculation of the ratio between the IC50 value toward H9c2 cells divided by the IC50 value in the anti-T. cruzi test. Infected Swiss mice were treated with 2 and 12 mg/kg/day via intravenous and oral, respectively, and the therapeutic efficacy was determined. The IC50 of LYC-NC and Free-LYC for epimastigotes of T. cruzi were similar. Both were active against amastigotes in cell culture, particularly Free-LYC. The SI of LYC-NC and Free-LYC were 45.38 and 32.11, respectively. LYC-NC 2 and 12 mg/kg/day cured parasitologically, 62.5% and 80% of the animals, respectively, infected with a strain resistant to treatment. The fluorescent NC was distributed in the cardiomyocyte cytoplasm, infected or not, and interacted with the trypomastigotes. Together, these results represent advances in demonstrating LYC as a potent new therapeutic option for treating CD.

Trypanosoma cruzi infection increases atherosclerotic lesion in ApoE-deficient mice.

Apolipoprotein E (ApoE) is the major ligand for the transporting and removal of chylomicrons and lipoproteins by the liver. Since the creation of the ApoE-knockout mice, it is well established that ApoE deficiency results in spontaneous atherosclerosis in aged animals. Atherosclerosis is also observed in animals infected with Trypanosoma cruzi, a protozoan that elicits a systemic inflammatory response in mammalian hosts, culminating in damage to cardiac, neuronal, and endothelial cells. Pro-atherogenic effects related to the experimental infection with T. cruzi may be induced by inflammatory components affecting the vascular wall. Herein, we evaluated whether infection with different strains of T. cruzi worsened the atherogenic lesions observed in aged ApoE-/- mice. After four weeks of infection with Berenice-78 (Be-78) or Colombian (Col) strains of the parasite, mice presented increased CCL2 and CCL5 production and high migration of inflammatory cells to cardiac tissue. Although the infection with either strain did not affect the survival rate, only the infection with Col strain caused abundant parasite growth in blood and heart and increased aortic root lesions in ApoE-/- mice. Our findings show, for the first time that ApoE exerts a protective anti-atherosclerotic role in the aortic root of mice in the acute phase of experimental infection with the Col strain of T. cruzi. Further studies should target ApoE and nutritional interventions to modulate susceptibility to cardiovascular disabilities after T. cruzi infection, minimizing the risk of death in both experimental animals and humans.

Higher oral efficacy of ravuconazole in self-nanoemulsifying systems in shorter treatment in experimental chagas disease.

We investigated the in vitro activity and selectivity, and in vivo efficacy of ravuconazole (RAV) in self-nanoemulsifying delivery system (SNEDDS) against Trypanosoma cruzi. Novel formulations of this poorly soluble C14-α-demethylase inhibitor may improve its efficacy in the experimental treatment. In vitro activity was determined in infected cardiomyocytes and efficacy in vivo evaluated in terms of parasitological cure induced in Y and Colombian strains of T. cruzi-infected mice. In vitro RAV-SNEDDS exhibited significantly higher potency of 1.9-fold at the IC50 level and 2-fold at IC90 level than free-RAV. No difference in activity with Colombian strain was observed in vitro. Oral treatment with a daily dose of 20 mg/kg for 30 days resulted in 70% of cure for RAV-SNEDDS versus 40% for free-RAV and 50% for 100 mg/kg benznidazole in acute infection (T. cruzi Y strain). Long-term treatment efficacy (40 days) was able to cure 100% of Y strain-infected animals with both RAV preparations. Longer treatment time was also efficient to increase the cure rate with benznidazole (Y and Colombian strains). RAV-SNEDDS shows greater efficacy in a shorter time treatment regimen, it is safe and could be a promising formulation to be evaluated in other pre-clinical models to treat T. cruzi and fungi infections.

Production of MMP-9 and inflammatory cytokines by Trypanosoma cruzi-infected macrophages.

Matrix metalloproteinases (MMPs) constitute a large family of Zn(2+) and Ca(2+) dependent endopeptidases implicated in tissue remodeling and chronic inflammation. MMPs also play key roles in the activation of growth factors, chemokines and cytokines produced by many cell types, including lymphocytes, granulocytes, and, in particular, activated macrophages. Their synthesis and secretion appear to be important in a number of physiological processes, including the inflammatory process. Here, we investigated the interaction between human and mouse macrophages with T. cruzi Colombian and Y strains to characterize MMP-9 and cytokine production in this system. Supernatants and total extract of T. cruzi infected human and mouse macrophages were obtained and used to assess MMP-9 profile and inflammatory cytokines. The presence of metalloproteinase activity was determined by zymography, enzyme-linked immunosorbent assay and immunoblotting assays. The effect of cytokines on MMP-9 production in human macrophages was verified by previous incubation of cytokines on these cells in culture, and analyzed by zymography. We detected an increase in MMP-9 production in the culture supernatants of T. cruzi infected human and mouse macrophages. The addition of IL-1ß or TNF-α to human macrophage cultures increased MMP-9 production. In contrast, MMP-9 production was down-modulated when human macrophage cultures were treated with IFN-γ or IL-4 before infection. Human macrophages infected with T. cruzi Y or Colombian strains produced increased levels of MMP-9, which was related to the production of cytokines such as IL-1ß, TNF-α and IL-6.

Protective effects of Theracurmin treatment during experimental infection of the Colombian strain of Trypanosoma cruzi at the testicular site.

Introduction: Chagas' disease is a tropical neglected illness caused by Trypanosoma cruzi and remains one of the most significant causes of morbidity and mortality in South and Central Americas. The disease is caused by a moderate to intense and persistent inflammatory response characterized by local upregulated expression and production of inflammatory mediators that favors the activation and recruitment of distinct cells of the immune system into different tissues to eliminate the parasites. Theracurmin is a curcumin's derived formulation of nanoparticles. Its anti-inflammatory properties make this bioactive compound a mitigating factor in pathological cases after an overwhelming inflammatory response. Methods: Our research focused on the testicular investigation in 28 mice infected by 103 trypomastigote forms of Colombian strain of T. cruzi and preventively treated with Theracurmin. The mice were treated with 30 mg/Kg of Theracurmin during the period of 30 days. At the 30th day post infection animals were euthanized, and its testicles were collected to morphological and immunological assays. Results: The animals infected and treated with Theracurmin presented a reduction in the testicular levels of IL-15 and IL-6. The volume density (%) of the tunica propria was also higher in all infected animals, but Theracurmin decreased this parameter in the treated animals. In the intertubular area, the percentage of some intertubular components was decreased in the infected animals such as the percentage and volume of Leydig cells, connective tissue, and macrophages. Discussion: Furthermore, our data pointed to the daily use of Theracurmin in the diet as a protective element of the testicular function.

Clonal structure of Trypanosoma cruzi Colombian strain (biodeme Type III): biological, isoenzymic and histopathological analysis of seven isolated clones

The clonal structure of the Colombian strain of Trypanosoma cruzi, biodeme Type III and zymodeme 1, was analyzed in order to characterize its populations and to establish its homogeneity or heterogeneity. Seven isolated clones presented the basic characteristics of Biodeme Type III, with the same patterns of parasitemic curves, tissue tropism to skeletal muscle and myocardium, high pathogenicity with extensive necrotic-inflammatory lesions from the 20th to 30th day of infection. The parental strain and its clones C1, C3, C4 and C6, determined the higher levels of parasitemia, 20 to 30 days of infection, with high mortality rate up to 30 days (79 to 100%); clones C2, C5 and C7 presented lower levels of parasitemia, with low mortality rates (7.6 to 23%). Isoenzymic patterns, characteristic of zymodeme 1, (Z1) were similar for the parental strain and its seven clones. Results point to a phenotypic homogeneity of the clones isolated from the Colombian strain and suggest the predominance of a principal clone, responsible for the biological behavior of the parental strain and clones.

A estrutura clonal da cepa Colombiana do Trypanosoma cruzi, biodema Tipo III e zimodema 1, foi analisada com o objetivo de caracterizar as suas populações e estabelecer a homogeneidade ou heterogeneidade das mesmas. Foram isolados sete clones, os quais apresentaram as características básicas do biodema Tipo III, com o mesmo padrão de curvas parasitêmicas, tropismo tecidual para músculo esquelético e miocárdio, alta patogenicidade, com extensas lesões necrótico-inflamatórias, do 20º ao 30º dia de infecção. A cepa parental e os clones C1, C3, C4 e C6 apresentaram os niveis mais elevados de parasitemia entre 20 e 30 dias pós-infecção e alto indice de mortalidade até 30 dias (79 a 100%); os clones C2, C5 e C7 apresentaram niveis mais baixos de parasitemia com baixa mortalidade até 30 dias (7,6 a 23%). Os padrões isoenzimáticos foram característicos do zimodema 1 (Z1) para a cepa parental e os sete clones. Os achados do presente trabalho indicam uma homogeneidade fenotípica entre os clones isolados da cepa Colombiana e sugerem a predominância de um clone principal, responsável pelo padrão de comportamento biológico da cepa parental e dos clones.