Anti-Trypanosoma cruzi Activity in vitro of Phases and Isolated Compounds from Excoecaria lucida Leaves.

BACKGROUND: Chagas disease is caused by the protozoan parasite Trypanosoma cruzi. This illness is found mainly in 21 Latin American countries and an estimated 8 million people are infected worldwide. The unsatisfactory chemotherapy provokes severe toxicity and resistant strains. Medicinal plants constitute a promising source of new drugs and remedies against all kinds of disorders, mainly infectious diseases arousing interest worldwide. OBJECTIVE: The aim of this study is the isolation, structural identification and evaluation of the trypanocidal activity of samples present in the Excoecaria lucida Sw. leaves. METHODS: Total extract (TE) of E. lucida Sw. leaves was obtained by ethanol extract therefore fractionated sequentially with hexane, ethyl acetate and n-butanol, to obtain three phases: Hex, EA and But, respectively. Ellagic acid (EL1) was purified from both EA and But phases, while EL2; a 1:1 stigmasterol-3-O-ß-D-glucopyranoside plus sitosterol-3-O-ß-D-glucopyranoside mixture was obtained from the Hex phase. Activity assays were performed using bloodstream and intracellular forms of T. cruzi and cytotoxicity assays using L929 fibroblasts. RESULTS: The EL1 and EL2 samples were more active against bloodstream trypomastigote forms with EC50 of 53.0±3.6 and 58.2±29.0 µg/mL, respectively; at 100 µg/mL. These samples also showed 70% of inhibition of L929 cells infection. Toxicity assays demonstrated that after 96 h of treatment only the fractions Hex and EA presented detectable cytotoxicity. CONCLUSION: Ellagic acid, stigmasterol-3-O-ß-D-glucopyranoside and sitosterol-3-O-ß-Dglucopyranoside are reported for the first time in E. lucida Sw. leaves as well as their biological activity studies supporting further investigations for Chagas disease treatment.

In Vitro, In Silico, and In Vivo Analyses of Novel Aromatic Amidines against Trypanosoma cruzi.

Five bis-arylimidamides were assayed as anti-Trypanosoma cruzi agents by in vitro, in silico, and in vivo approaches. None were considered to be pan-assay interference compounds. They had a favorable pharmacokinetic landscape and were active against trypomastigotes and intracellular forms, and in combination with benznidazole, they gave no interaction. The most selective agent (28SMB032) tested in vivo led to a 40% reduction in parasitemia (0.1 mg/kg of body weight/5 days intraperitoneally) but without mortality protection. In silico target fishing suggested DNA as the main target, but ultrastructural data did not match.

Determinantes da densidade mineral óssea na pós-menopausa / Determinants of bone mineral density in post-menopause

Pós-menopausa é período de maior perda óssea e faz-se necessário instituir medidas preventivas que amenizem sua progressão. Objetivo: correlacionar o escore da densidade mineral óssea (DMO) e seus fatores de risco, buscando determinar aqueles que mais a influenciam. Método: estudo transversal, descritivo de 62 mulheres na pós-menopausa, saudáveis, idade média de 56,82 ± 4,02 anos, avaliadas quanto aos fatores de risco para osteoporose e nível de atividade física. Absorção de dupla energia de raios-X (DXA) avaliou coluna lombar e fêmur proximal. Os grupos, DMO normal e diminuída, foram analisados pelos testes T de Student, qui-quadrado e correlações. Resultados: Mulheres com menor índice de massa corporal (IMC), maior idade e maior tempo de menopausa apresentaram menor DMO em fêmur. Raça negra e ausência de história familiar correlacionaram-se com maior DMO. Conclusão: IMC, idade, peso, história familiar de osteoporose, raça e tempo de menopausa foram os principais fatores determinantes da DMO em mulheres na pós-menopausa.

Post-menopause is the period of greatest bone loss and it is necessary to introduce preventative measures to mitigate its progression. Aim: compare the score of bone mineral density (BMD) and their risk factors and to determine those most influencing. Method: Cross-sectional, descriptive study of 62 postmenopausal women, healthy, average age 56.82 ± 4.02 years, evaluated for risk factors for osteoporosis and physical activity level. Absorption dual energy X-ray absorptiometry (DXA) evaluated lumbar spine and proximal femur. Groups, normal and reduced BMD were analyzed by Student’s t test, chisquare and correlations. Results: Women with lower body mass index (BMI), older age and longer duration of menopause had lower BMD at the femur. Black race and absence of family history correlated with higher BMD. Conclusion: BMI, age, weight, family history of osteoporosis, race, and time since menopause were the main determinants of BMD in postmenopausal women.

Clinical Candidate VT-1161's Antiparasitic Effect In Vitro, Activity in a Murine Model of Chagas Disease, and Structural Characterization in Complex with the Target Enzyme CYP51 from Trypanosoma cruzi.

A novel antifungal drug candidate, the 1-tetrazole-based agent VT-1161 [(R)-2-(2,4-difluorophenyl)-1,1-difluoro-3-(1H-tetrazol-1-yl)-1-{5-[4-(2,2,2-trifluoroethoxy)phenyl]pyridin-2-yl}propan-2-ol], which is currently in two phase 2b antifungal clinical trials, was found to be a tight-binding ligand (apparent dissociation constant [Kd], 24 nM) and a potent inhibitor of cytochrome P450 sterol 14α-demethylase (CYP51) from the protozoan pathogen Trypanosoma cruzi. Moreover, VT-1161 revealed a high level of antiparasitic activity against amastigotes of the Tulahuen strain of T. cruzi in cellular experiments (50% effective concentration, 2.5 nM) and was active in vivo, causing >99.8% suppression of peak parasitemia in a mouse model of infection with the naturally drug-resistant Y strain of the parasite. The data strongly support the potential utility of VT-1161 in the treatment of Chagas disease. The structural characterization of T. cruzi CYP51 in complex with VT-1161 provides insights into the molecular basis for the compound's inhibitory potency and paves the way for the further rational development of this novel, tetrazole-based inhibitory chemotype both for antiprotozoan chemotherapy and for antifungal chemotherapy.

Efeitos da atividade física sobre a densidade mineral óssea de mulheres saudáveis na pré-menopausa / Physical activity effects on bone mineral density of healthy women in pre-menopause

A atividade física representa um importante estímulo ao aumento da densidade mineral óssea (DMO). Como a resistência dos ossos está associada tanto a DMO, quanto a microestrutura e propriedades do material, melhorias na massa óssea são importantes na prevenção de osteoporose na idade mais avançada. Apesar de muitos estudos sobre o tema, não existe consenso sobre qual seria o melhor tipo de atividade física, intensidade e frequência para melhorias na osteogênese e promoção do ganho de DMO. O objetivo deste estudo foi investigar os tipos de atividades físicas com melhor efeito osteogênico de aumento da DMO em mulheres saudáveis na pré-menopausa. Metodologia: Realizou-se levantamento bibliográfico de artigos científicos nas bases de dados Pubmede Direct Science publicados nos últimos dez anos. Foram selecionados estudos controlados com exercícios de alto impacto e resistido. Utilizou-se análise sistematizada dos artigos selecionados. Resultados: Foram incluídos 15 artigos nesta revisão, os quais foram separados em dois grupos, conforme o tipo de exercício. Foi realizada análise comparativa de metodologias utilizadas e resultados alcançados. Constatou-se maior eficiência do protocolo de exercício de alto impacto, mesmo em curto período de execução para aumento da DMO do fêmur proximal (colo femoral e região intertrocantérica). Em menor frequência, foi observado aumento da DMO na coluna lombar quando exercícios resistidos ou de impactos maiores foram usados. Conclusões: A maioria dos artigos executou protocolo experimental em período relativamente curto (6 meses), demonstrando que programas de exercícios simples, de fácil execução, curto período de aplicação e sem uso de aparelhos específicos são suficientes para promover remodelação óssea em sítios específicos com aumento da DMO...

Physical activity is an important stimulus to increase bone mineral density (BMD). Where by the resistance of the bone is associated with BMD, microstructure and material properties, improvements in bone mass are important to prevent osteoporosis in old ages. Despite many studies on the subject, there is no consensus on what is the best type of exercise, intensity and frequency for improvements in osteogenesis and promotion of BMD gain. This study aimed to investigate the types of physical activities that results in better osteogenic effects on increasing BMD in healthy premenopausal women. Methodology: We searched scientific articles in Pubmed and Science Direct databases published in the last ten years. We selected controlled studies which used high-impact activities or resistance training. We used systematic analysis of the selected articles. Results: Fifteen articles were included in this review, which were separated into two groups according to the type of exercise. We performed a comparative analysis of the methods used and the results achieved. There were more efficient protocols using high impact exercise even if it was a short-term program resulting in increased BMD in the proximal femur (femoral neck and intertrochanteric region). Conclusion: There were fewer studies observing increases in BMD at the lumbar spine when resistance exercise with load or high impact loads were used. Most experimental protocols performed in relatively short-term programs (6 months) demonstrated that exercise programs that were simple, easy to perform, and not using special devices are sufficient to promote bone remodeling at specific sites resultingin increased BMD...

Experimental Chemotherapy for Chagas Disease: A Morphological, Biochemical, and Proteomic Overview of Potential Trypanosoma cruzi Targets of Amidines Derivatives and Naphthoquinones.

Chagas disease (CD), caused by Trypanosoma cruzi, affects approximately eight million individuals in Latin America and is emerging in nonendemic areas due to the globalisation of immigration and nonvectorial transmission routes. Although CD represents an important public health problem, resulting in high morbidity and considerable mortality rates, few investments have been allocated towards developing novel anti-T. cruzi agents. The available therapy for CD is based on two nitro derivatives (benznidazole (Bz) and nifurtimox (Nf)) developed more than four decades ago. Both are far from ideal due to substantial secondary side effects, limited efficacy against different parasite isolates, long-term therapy, and their well-known poor activity in the late chronic phase. These drawbacks justify the urgent need to identify better drugs to treat chagasic patients. Although several classes of natural and synthetic compounds have been reported to act in vitro and in vivo on T. cruzi, since the introduction of Bz and Nf, only a few drugs, such as allopurinol and a few sterol inhibitors, have moved to clinical trials. This reflects, at least in part, the absence of well-established universal protocols to screen and compare drug activity. In addition, a large number of in vitro studies have been conducted using only epimastigotes and trypomastigotes instead of evaluating compounds' activities against intracellular amastigotes, which are the reproductive forms in the vertebrate host and are thus an important determinant in the selection and identification of effective compounds for further in vivo analysis. In addition, due to pharmacokinetics and absorption, distribution, metabolism, and excretion characteristics, several compounds that were promising in vitro have not been as effective as Nf or Bz in animal models of T. cruzi infection. In the last two decades, our team has collaborated with different medicinal chemistry groups to develop preclinical studies for CD and investigate the in vitro and in vivo efficacy, toxicity, selectivity, and parasite targets of different classes of natural and synthetic compounds. Some of these results will be briefly presented, focusing primarily on diamidines and related compounds and naphthoquinone derivatives that showed the most promising efficacy against T. cruzi.

Experimental chemotherapy for Chagas disease: 15 years of research contributions from in vivo and in vitro studies.

Chagas disease, which is caused by the intracellular parasite Trypanosoma cruzi, is a neglected illness with 12-14 million reported cases in endemic geographic regions of Latin America. While the disease still represents an important public health problem in these affected areas, the available therapy, which was introduced more than four decades ago, is far from ideal due to its substantial toxicity, its limited effects on different parasite stocks, and its poor activity during the chronic phase of the disease. For the past 15 years, our group, in collaboration with research groups focused on medicinal chemistry, has been working on experimental chemotherapies for Chagas disease, investigating the biological activity, toxicity, selectivity and cellular targets of different classes of compounds on T. cruzi. In this report, we present an overview of these in vitro and in vivo studies, focusing on the most promising classes of compounds with the aim of contributing to the current knowledge of the treatment of Chagas disease and aiding in the development of a new arsenal of candidates with anti-T. cruzi efficacy.

In vitro analyses of the effect of aromatic diamidines upon Trypanosoma cruzi.

OBJECTIVES: Aromatic diamidines (ADs) have been recognized as promising antiparasitic agents. Therefore, in the present work, the in vitro trypanocidal effect of 11 ADs upon the relevant clinical forms of Trypanosoma cruzi was evaluated, as well as determining their toxicity to mammalian cells and their subcellular localization. METHODS: The trypanocidal effect upon trypomastigotes and amastigotes was evaluated by light microscopy through the determination of the IC(50) values. The cytotoxicity was determined by the MTT colorimetric assay against mouse cardiomyocytes. For the subcellular localization, transmission electron microscopy and fluorescence approaches were used. The fluorescence intensity within the kinetoplast DNA (kDNA) and nuclear DNA (nDNA) of treated parasites was determined using the Image J program. RESULTS: Compounds 2, 5 and 7 showed the lowest IC(50) values (micromolar range) against intracellular amastigotes and trypomastigotes. In the presence of blood, all the tested ADs exhibited a reduction of their activity. The compounds did not exhibit toxicity to cardiac cells and the highest selectivity index (SI) was achieved by compound 5 with an SI of >137 for trypomastigotes and compound 7 with an SI of >107 for intracellular parasites. The subcellular effects upon bloodstream forms treated with compounds 5 and 7 were mainly on kDNA, leading to its disorganization. The higher accumulation in the kDNA observed for all tested ADs was not directly related to their efficacy. CONCLUSIONS: Our results show the high activity of this new series of ADs against both trypomastigote and amastigote forms, with excellent SIs, especially compound 7, which merits further in vivo evaluation.

Experimental chemotherapy for Chagas disease: 15 years of research contributions from in vivo and in vitro studies

Chagas disease, which is caused by the intracellular parasite Trypanosoma cruzi, is a neglected illness with 12-14 million reported cases in endemic geographic regions of Latin America. While the disease still represents an important public health problem in these affected areas, the available therapy, which was introduced more than four decades ago, is far from ideal due to its substantial toxicity, its limited effects on different parasite stocks, and its poor activity during the chronic phase of the disease. For the past 15 years, our group, in collaboration with research groups focused on medicinal chemistry, has been working on experimental chemotherapies for Chagas disease, investigating the biological activity, toxicity, selectivity and cellular targets of different classes of compounds on T. cruzi. In this report, we present an overview of these in vitro and in vivo studies, focusing on the most promising classes of compounds with the aim of contributing to the current knowledge of the treatment of Chagas disease and aiding in the development of a new arsenal of candidates with anti-T. cruzi efficacy.

Trypanosoma cruzi modulates the expression of Rabs and alters the endocytosis in mouse cardiomyocytes in vitro.

Chagas disease is an incurable illness caused by the protozoan Trypanosoma cruzi. Cardiomyocytes represent important targets for the parasite infection and alterations in their physiology were reported. Because endocytosis is involved in different cellular events and guanosine triphosphatase (GTPase) Rab proteins play important roles in various aspects of the membrane traffic, our aim was to characterize the expression of Rab proteins in T. cruzi-infected cardiomyocytes, which displayed a downregulation of Rab7 and Rab11, whereas the expression of Rab5a was maintained in the infected cultures even after longer periods of parasite internalization, but early endosome antigen 1 was partially downregulated. The parasite infection also decreased the uptake of fluid phase ligands by the cardiac cultures. The regulation of GTPase proteins and effector molecules can contribute to the altered physiology of the host cells by modifying the normal incoming of nutrients as well as interfering with other important events related to the endocytic pathway.