Selected Aspects of the Analytical and Pharmaceutical Profiles of Nifurtimox.

Nifurtimox is a nitroheterocyclic drug employed for treatment of trypanosomiases (Chagas disease and West African sleeping sickness); its use for certain cancers has also been assessed. Despite having been in the market for over 50 years, knowledge of nifurtimox is still fragmentary and incomplete. Relevant aspects of the chemistry and biology of nifurtimox are reviewed to summarize the current knowledge of this drug. These comprise its chemical synthesis and the preparation of some analogues, as well as its chemical degradation. Selected physical data and physicochemical properties are also listed, along with different approaches toward the analytical characterization of the drug, including electrochemical (polarography, cyclic voltammetry), spectroscopic (ultraviolet-visible, nuclear magnetic resonance, electron spin resonance), and single crystal X-ray diffractometry. The array of polarographic, ultraviolet-visible spectroscopic, and chromatographic methods available for the analytical determination of nifurtimox (in bulk drug, pharmaceutical formulations, and biological samples), are also presented and discussed, along with chiral chromatographic and electrophoretic alternatives for the separation of the enantiomers of the drug. Aspects of the drug likeliness of nifurtimox, its classification in the Biopharmaceutical Classification System, and available pharmaceutical formulations are detailed, whereas pharmacological, chemical, and biological aspects of its metabolism and disposition are discussed.

The Potential of Secondary Metabolites from Plants as Drugs or Leads against Trypanosoma cruzi-An Update from 2012 to 2021.

BACKGROUND: Chagas disease (American Trypanosomiasis) is classified by the World Health Organization (WHO) as one of the seventeen neglected tropical diseases (NTD), affecting, mainly, several regions of Latin America. INTRODUCTION: However, immigration has expanded the range of this disease to other continents. Thousands of patients with Chagas disease die annually, yet no new therapeutics for Chagas disease have been approved, with only nifurtimox and benznidazole available. Treatment with these drugs presents several challenges, including protozoan resistance, toxicity, and low efficacy. Natural products, including the secondary metabolites found in plants, offer a myriad of complex structures that can be sourced directly or optimized for drug discovery. METHODS: Therefore, this review aims to assess the literature from the last 10 years (2012-2021) and present the anti-T. cruzi compounds isolated from plants in this period, as well as briefly discuss computational approaches and challenges in natural product drug discovery. Using this approach, more than 350 different metabolites were divided based on their biosynthetic pathway alkaloids, terpenoids, flavonoids, polyketides, and phenylpropanoids which displayed activity against different forms of this parasite epimastigote, trypomastigote and more important, the intracellular form, amastigote. CONCLUSION: In this aspect, there are several compounds with high potential which could be considered as a scaffold for the development of new drugs for the treatment of Chagas disease-for this, more advanced studies must be performed including pharmacokinetics (PK) and pharmacodynamics (PD) analysis as well as conduction of in vivo assays, these being important limitations in the discovery of new anti-T. cruzi compounds.

Molecular Characterization of Four Mexican Isolates of Trypanosoma cruzi and Their Profile Susceptibility to Nifurtimox.

PURPOSE: The objective of this study was to molecularly characterize Mexican isolates of T. cruzi obtained from infected triatomine bugs (the vectors of T. cruzi) and to evaluate their susceptibility to Nifurtimox (NFX). METHODS: Three isolates obtained from Triatoma dimidiata (collected in the State of Veracruz) and one isolate obtained from Triatoma bassolsae (collected in the State of Puebla) were molecularly characterized and the expression of genes associated with natural resistance to NFX was analyzed by qPCR. RESULTS: Molecular characterization by PCR showed that isolates Zn3, Zn5, and SRB1 belong to the DTU TcI, while isolate Sum3 belongs to TcIV. The latter was also confirmed by sequencing of mitochondrial genes. Isolate Zn5 was the most sensitive to treatment with NFX (IC50, 6.8 µM), isolates SRB1 and Zn3 were partially resistant (IC50, 12.8 µM and 12.7 µM) and isolate Sum3 showed a high degree of resistance to NFX (IC50, 21.4 µM). We also found an association between decreased NTR1 or OYE gene expression with NFX resistance. CONCLUSION: Our results also evidenced a high variability in the susceptibility to NFX of these T. cruzi isolates Central and Southeastern Mexico, suggesting the presence of naturally resistant isolates circulating in the country. These results have important implications for defining treatment policies for patients with Chagas disease.

Trypanosoma cruzi Mitochondrial Peroxiredoxin Promotes Infectivity in Macrophages and Attenuates Nifurtimox Toxicity.

Trypanosoma cruzi is the causative agent of Chagas disease which is currently treated by nifurtimox (NFX) and benznidazole (BZ). Nevertheless, the mechanism of action of NFX is not completely established. Herein, we show the protective effects of T. cruzi mitochondrial peroxiredoxin (MPX) in macrophage infections and in response to NFX toxicity. After a 3-day treatment of epimastigotes with NFX, MPX content increased (2.5-fold) with respect to control, and interestingly, an MPX-overexpressing strain was more resistant to the drug. The generation of mitochondrial reactive species and the redox status of the low molecular weight thiols of the parasite were not affected by NFX treatment indicating the absence of oxidative stress in this condition. Since MPX was shown to be protective and overexpressed in drug-challenged parasites, non-classical peroxiredoxin activity was studied. We found that recombinant MPX exhibits holdase activity independently of its redox state and that its overexpression was also observed in temperature-challenged parasites. Moreover, increased holdase activity (2-fold) together with an augmented protease activity (proteasome-related) and an enhancement in ubiquitinylated proteins was found in NFX-treated parasites. These results suggest a protective role of MPX holdase activity toward NFX toxicity. Trypanosoma cruzi has a complex life cycle, part of which involves the invasion of mammalian cells, where parasite replication inside the host occurs. In the early stages of the infection, macrophages recognize and engulf T. cruzi with the generation of reactive oxygen and nitrogen species toward the internalized parasite. Parasites overexpressing MPX produced higher macrophage infection yield compared with wild-type parasites. The relevance of peroxidase vs. holdase activity of MPX during macrophage infections was assessed using conoidin A (CA), a covalent, cell-permeable inhibitor of peroxiredoxin peroxidase activity. Covalent adducts of MPX were detected in CA-treated parasites, which proves its action in vivo. The pretreatment of parasites with CA led to a reduced infection index in macrophages revealing that the peroxidase activity of peroxiredoxin is crucial during this infection process. Our results confirm the importance of peroxidase activity during macrophage infection and provide insights for the relevance of MPX holdase activity in NFX resistance.

Effect of B-NIPOx in Experimental Trypanosoma cruzi Infection in Mice.

Chagas disease is caused by Trypanosoma cruzi and represents a major public health problem, which is endemic in Latin America and emerging in the rest of the world. The two drugs that are currently available for its treatment, Benznidazole and Nifurtimox, are partially effective in the chronic phase of the disease. In this study, we designed and synthesized the benzyl ester of N-isopropyl oxamic acid (B-NIPOx), which is a non-polar molecule that crosses cell membranes. B-NIPOx is cleaved inside the parasite by carboxylesterases, releasing benzyl alcohol (a molecule with antimicrobial activity), and NIPOx, which is an inhibitor of α-hydroxy acid dehydrogenase isozyme II (HADH-II), a key enzyme in T. cruzi metabolism. We evaluated B-NIPOx cytotoxicity, its toxicity in mice, and its inhibitory activity on purified HADH-II and on T. cruzi homogenates. We then evaluated the trypanocidal activity of B-NIPOx in vitro and in vivo and its effect in the intestine of T. cruzi-infected mice. We found that B-NIPOx had higher trypanocidal activity on epimastigotes and trypomastigotes than Benznidazole and Nifurtimox, that it was more effective to reduce blood parasitemia and amastigote nests in infected mice, and that, in contrast to the reference drugs, it prevented the development of Chagasic enteropathy.

In vitro susceptibility to benznidazole, nifurtimox and posaconazole of Trypanosoma cruzi isolates from Paraguay / [Sensibilidad in vitro a benznidazol, nifurtimox y posaconazol de cepas de Trypanosoma cruzi de Paraguay].

Introduction: Trypanosoma cruzi, the causative agent of Chagas disease, shows substantial phenotypic and genotypic heterogeneity, which can influence the epidemiological and clinical variations of the disease and the sensitivity to the drugs used in the treatment. Objective: To assess the in vitro susceptibility to benznidazole, nifurtimox, and posaconazole of 40 cloned strains of T. cruzi isolated in Paraguay belonging to different genotypes, hosts, and localities. Materials and methods: We incubated the parasites in their epimastigote stage in LIT culture medium with different concentrations of each drug in triplicate assays. The degree of susceptibility was estimated by the inhibitory concentrations of 50 and 90% (IC50 and IC90) to obtain the average values and the standard deviation for each strain and drug. We determined the statistical significance between groups by analysis of variances with the Wilcoxon/Kruskal-Wallis non-parametric test and values of p<0.05. Results: A wide range of drug response was observed. Two groups of parasites (A and B) were identified as having significant differences in susceptibility to benznidazole (p<0.0001), and three groups (A, B, C) to nifurtimox and posaconazole (p<0.0001). Conclusions: Overall, the isolates were more susceptible to nifurtimox than benznidazole and posaconazole. Such differences highlight the heterogeneity of T. cruzi populations circulating in Paraguay, an aspect to consider in the treatment and follow up of patients.

Introducción. Trypanosoma cruzi, agente causal de la enfermedad de Chagas, exhibe una sustancial heterogeneidad fenotípica y genotípica que puede influir en las variaciones epidemiológicas y clínicas de la enfermedad, así como en la sensibilidad a los fármacos utilizados en el tratamiento. Objetivo. Evaluar la sensibilidad in vitro al benznidazol, el nifurtimox y el posaconazol de 40 cepas clonadas de T. cruzi de Paraguay, con distintos genotipos, huéspedes y localidades de origen. Materiales y métodos. En su estado epimastigote, los parásitos se incubaron en medio de cultivo LIT (Liver Infusion Tryptose) con diferentes concentraciones de cada fármaco en ensayos por triplicado. El grado de sensibilidad se estimó a partir de las concentraciones inhibitorias del 50 y el 90% (IC50 e IC90) y se obtuvieron los valores promedio y la desviación estándar de cada cepa y fármaco. La significación estadística entre grupos se determinó mediante análisis de varianzas con el test no paramétrico de Wilcoxon/Kruskal-Wallis y valores de p<0,05. Resultados. Se observó un amplio rango de respuesta a los fármacos. Se identificaron dos grupos de parásitos (A y B) con diferencias significativas en la sensibilidad al benznidazol (p<0,0001), y tres grupos (A, B, C) en cuanto a la sensibilidad al nifurtimox y el posaconazol (p<0,0001). Conclusiones. En general, las cepas fueron más sensibles al nifurtimox que al benznidazol y el posaconazol. Estas diferencias evidencian la heterogeneidad de las poblaciones de T. cruzi que circulan en Paraguay, lo que debe considerarse en el tratamiento y el seguimiento de las personas afectadas.

Phenothiazinium Dyes Are Active against Trypanosoma cruzi In Vitro.

Chagas disease is a tropical illness caused by the protozoan Trypanosoma cruzi. The disease affects populations of the Americas and has been spread to other continents due to the migration process. The disease is partially controlled by two drugs, Benznidazole and Nifurtimox. These molecules are active in the acute phase of the infection but are usually ineffective during the symptomatic chronic phase. Several research groups have developed novel candidates to control Chagas disease; however, no novel commercial formulation is available. In this article, we described the anti-T. cruzi effects of phenothiazinium dyes in amastigote and trypomastigote forms of the parasite. Methylene Blue, New Methylene Blue, Toluidine Blue O, and 1,9-Dimethyl Methylene Blue inhibited the parasite proliferation at nanomolar concentrations and also demonstrated low toxicity in host cells. Moreover, combinations of phenothiazinium dyes indicated a synergic pattern against amastigotes compared to the Benznidazole counterparts. Phenothiazinium dyes levels of reactive oxygen species (ROS) and decreased the mitochondrial potential in trypomastigotes, indicating the mechanism of action of the dyes in T. cruzi. Our article offers a basis for future strategies for the control of Chagas disease using low-cost formulations, an important point for endemic underdeveloped regions.

Developments on treatment of Chagas disease - from discovery to current times.

OBJECTIVE: This work aims to collect publications of available drugs for reposition and new substance development against the Chagas disease, since they represent the beginning of a path for new discoveries of viable alternatives to improve the prognosis of millions of patients around the world. PATIENTS AND METHODS: An extended research on English and Portuguese-language literature in the Scientific Electronic Library Online - Scielo, SciFinder and PubMed - database was made. The bibliography was screened using the keywords "Chagas Disease" and "Treatment". RESULTS: Despite the low resources available for research and development of drugs against Chagas disease, the knowledge produced in this area is large but not directly proportional to the therapeutic advances. Two categories were analyzed, such as drug repositioning, and new substances were researched. CONCLUSIONS: Even if great findings were reported, more efforts are necessary to find new therapies against Trypanosoma cruzi (T. cruzi).

Nifurtimox response of Trypanosoma cruzi isolates from an outbreak of Chagas disease in Caracas, Venezuela.

BACKGROUND & OBJECTIVES: In Venezuela, Chagas disease (ChD) is considered a serious health problem, with about 6 million people at risk; and acute outbreaks due to oral transmission of Chagas Disease (OChD) are becoming increasingly important. In 2007 there was a major outbreak of OChD and although patients from this episode were treated with nifurtimox (Lampit®-Bayer), about 70% therapeutic failure was registered. These results led us to examine whether parasite's drug susceptibility was related to this therapeutic failure. METHODS: The Trypanosoma cruzi parasites were isolated by haemoculture of the peripheral blood drawn from the pre- and post-nifurtimox treated patients infected in the 2007 OChD outbreak at Caracas, Venezuela. The in vitro assays for drug testing were performed by the MTT methodology followed by calculation of inhibitory concentration-50 (IC50) values. RESULTS: Parasite isolates obtained from the infected patients prior and after nifurtimox treatment when subjected to variable concentrations of the drug showed great heterogeneity in susceptibility with IC50 values ranging from 4.07 ± 1.82 to 94.92 ± 7.24 µM. INTERPRETATION & CONCLUSION: The high heterogeneity in nifurtimox IC50 values in the isolates and clones from the OChD patients, suggests that the therapeutic failure to nifurtimox could be due in part to a phenotypic variability that existed in the wild parasite population at the original source of contamination. Though, further pharmacological studies are needed to confirm the existence of natural nifurtimox resistance in the parasite.

New 1,2,3-triazole-based analogues of benznidazole for use against Trypanosoma cruzi infection: In vitro and in vivo evaluations.

Chagas disease has spread throughout the world mainly because of the migration of infected individuals. In Brazil, only benznidazole (Bnz) is used; however, it is toxic and not active in the chronic phase, and cases of resistance are described. This work aimed at the synthesis and the trypanocidal evaluation in vitro and in vivo of six new Bnz analogues (3-8). They were designed by exploring the bioisosteric substitution between the amide group contained in Bnz and the 1,2,3-triazole ring. All the compounds were synthesized in good yields. With the exception of compound 7, the in vitro biological evaluation shows that all Bnz analogues were active against the amastigote form, whereas only compounds 3, 4, 5, and 8 were active against trypomastigote. Compounds 4 and 5 showed the most promising activities in vitro against the form of trypomastigote, being more active than Bnz. In vivo evaluation of compounds, 3-8 showed lower potency and higher toxicity than Bnz. Although the 1,2,3-triazole ring has been described in the literature as an amide bioisostere, its substitution here has reduced the activity of the compounds and made them more toxic. Thus, further molecular optimization could provide novel therapeutic agents for Chagas' disease.

Evaluation of Trypanocidal and Antioxidant Activities of a Selected Series of 3-amidocoumarins.

BACKGROUND: Neglected diseases are becoming more prevalent due to globalization. This has inspired active research in the development of new drugs for the treatment of parasitic diseases such as Chagas disease. OBJECTIVES: With the aim of finding new trypanocidal agents, we report the in vitro evaluation of a new series of 3-amidocoumarins with or without hydroxyl substituents at position 4 of the coumarin ring. METHODS: Electrochemical and biological assays were performed in order to assess the antioxidant and trypanocidal potential of these compounds and to better understand the mechanisms involved in their activity. RESULTS: Most of the studied compounds showed high trypanocidal activity against both epimastigote and trypomastigote forms, with IC50 values in the low micromolar range. Some of them have greater activity and selectivity than the reference compound, nifurtimox. CONCLUSION: Compound 2 is the most active of this series, being also non-cytotoxic against murine RAW 264.7 macrophages. Electrochemical and radical scavenging experiments were carried out, providing new information about the profile of the best derivatives, and the potential therapeutic application of the new 3-amidocoumarins.

Drug Discovery for Paediatric Chagas Disease.

Chagas disease is caused by the parasite Trypanosoma cruzi and is regularly found among particular people living in Central and South America. Paediatric Chagas disease occurs in 1-10% of infants of infected mothers. The major important point considered in the treatment of congenital Chagas disease focuses on killing the parasite in acute infection and managing signs and symptoms in later stages. Nowadays, two drugs benznidazole and nifurtimox are currently available in the market for the treatment of paediatric Chagas disease.

Novel scaffolds for inhibition of Cruzipain identified from high-throughput screening of anti-kinetoplastid chemical boxes.

American Trypanosomiasis or Chagas disease is a prevalent, neglected and serious debilitating illness caused by the kinetoplastid protozoan parasite Trypanosoma cruzi. The current chemotherapy is limited only to nifurtimox and benznidazole, two drugs that have poor efficacy in the chronic phase and are rather toxic. In this scenario, more efficacious and safer drugs, preferentially acting through a different mechanism of action and directed against novel targets, are particularly welcome. Cruzipain, the main papain-like cysteine peptidase of T. cruzi, is an important virulence factor and a chemotherapeutic target with excellent pre-clinical validation evidence. Here, we present the identification of new Cruzipain inhibitory scaffolds within the GlaxoSmithKline HAT (Human African Trypanosomiasis) and Chagas chemical boxes, two collections grouping 404 non-cytotoxic compounds with high antiparasitic potency, drug-likeness, structural diversity and scientific novelty. We have adapted a continuous enzymatic assay to a medium-throughput format and carried out a primary screening of both collections, followed by construction and analysis of dose-response curves of the most promising hits. Using the identified compounds as a starting point a substructure directed search against CHEMBL Database revealed plausible common scaffolds while docking experiments predicted binding poses and specific interactions between Cruzipain and the novel inhibitors.

Trypanothione Reductase: A Target for the Development of Anti- Trypanosoma cruzi Drugs.

BACKGROUND & OBJECTIVE: Chagas disease or American trypanosomiasis is a major parasitic disease in Latin America with restricted available treatment: nifurtimox and benznidazole. These two drugs are ineffective in the chronic phase of the disease; therefore, there is a need for the development of new, efficient and safe drugs for the treatment of this pathology. With this goal, one of the promising targets is trypanothione reductase (TR), a key enzyme in the metabolism of Trypanosoma cruzi. CONCLUSION: In this review, we analyse the importance of TR as a drug target, as well as the well-known and new inhibitors reported in the last decade as potential therapeutic agents for Chagas disease.

TcI, TcII and TcVI Trypanosoma cruzi samples from Chagas disease patients with distinct clinical forms and critical analysis of in vitro and in vivo behavior, response to treatment and infection evolution in murine model.

The clonal evolution of Trypanosoma cruzi sustains scientifically the hypothesis of association between parasite's genetic, biological behavior and possibly the clinical aspects of Chagas disease in patients from whom they were isolated. This study intended to characterize a range of biological properties of TcI, TcII and TcVI T. cruzi samples in order to verify the existence of these associations. Several biological features were evaluated, including in vitro epimastigote-growth, "Vero"cells infectivity and growth, along with in vivo studies of parasitemia, polymorphism of trypomastigotes, cardiac inflammation, fibrosis and response to treatment by nifurtimox during the acute and chronic murine infection. The global results showed that the in vitro essays (acellular and cellular cultures) TcII parasites showed higher values for all parameters (growth and infectivity) than TcVI, followed by TcI. In vivo TcII parasites were more virulent and originated from patients with severe disease. Two TcII isolates from patients with severe pathology were virulent in mice, while the isolate from a patient with the indeterminate form of the disease caused mild infection. The only TcVI sample, which displayed low values in all parameters evaluated, was also originated of an indeterminate case of Chagas disease. Response to nifurtimox was not associated to parasite genetic and biology, as well as to clinical aspects of human disease. Although few number of T. cruzi samples have been analyzed, a discreet correlation between parasite genetics, biological behavior in vitro and in vivo (murine model) and the clinical form of human disease from whom the samples were isolated was verified.

Aspectos epidemiológicos e clínicos da Doença de Chagas aguda no Brasil e na américa Latina / Epidemiological and clinical aspects of acute Chagas Disease in Brazil and Letin America

surgindo em um cenário não habitual, relacionado com a forma de transmissão. Atualmente, a transmissão por via oral envolvendo alimentos contaminados é a principal via de infecção humana, com surtos em toda a América Latina. Entre os sintomas da fase aguda, destacam-se febre prolongada, quase sempre acompanhada de mal-estar, adinamia, cefaleia e perda do apetite, acompanhados de manifestações sistêmicas, tais como adenomegalias e hepatoesplenomegalias. As manifestações cardíacas variam desde quadros assintomáticos até graus variáveis de insuficiência cardíaca aguda ou choque cardiogênico e morte. O tratamento da fase aguda com antiparasitários deve sempre ser instituído, pois existem algumas evidencias de melhor evolução clínica em relatos de casos

Acute Chagas disease shows changes in the epidemiological situation, reappearing in an unusual scenario related to the mode of transmission. Currently, the oral transmission involving contaminated food is the main route of human infection with outbreaks throughout Latin America. Among the symptoms of the acute phase stand out prolonged fever, often accompanied by malaise, asthenia, headache and loss of appetite, accompanied by systemic manifestations such as lymphadenopathy and hepatosplenomegaly. Cardiac manifestations range from asymptomatic clinical statuses to varying degrees of acute heart failure or cardiogenic shock and death. Treatment of acute phase with antiparasitic agents should always be provided, as there is some evidence of better clinical outcome in case reports

Differential Gel Electrophoresis (DIGE) Evaluation of Naphthoimidazoles Mode of Action: A Study in Trypanosoma cruzi Bloodstream Trypomastigotes.

BACKGROUND: The obligate intracellular protozoan Trypanosoma cruzi is the causative agent of Chagas disease, a neglected illness affecting millions of people in Latin America that recently entered non-endemic countries through immigration, as a consequence of globalization. The chemotherapy for this disease is based mainly on benznidazole and nifurtimox, which are very efficient nitroderivatives against the acute stage but present limited efficacy during the chronic phase. Our group has been studying the trypanocidal effects of naturally occurring quinones and their derivatives, and naphthoimidazoles derived from ß-lapachone N1, N2 and N3 were the most active. To assess the molecular mechanisms of action of these compounds, we applied proteomic techniques to analyze treated bloodstream trypomastigotes, which are the clinically relevant stage of the parasite. METHODOLOGY/PRINCIPAL FINDINGS: The approach consisted of quantification by 2D-DIGE followed by MALDI-TOF/TOF protein identification. A total of 61 differentially abundant protein spots were detected when comparing the control with each N1, N2 or N3 treatment, for 34 identified spots. Among the differentially abundant proteins were activated protein kinase C receptor, tubulin isoforms, asparagine synthetase, arginine kinase, elongation factor 2, enolase, guanine deaminase, heat shock proteins, hypothetical proteins, paraflagellar rod components, RAB GDP dissociation inhibitor, succinyl-CoA ligase, ATP synthase subunit B and methionine sulfoxide reductase. CONCLUSION/SIGNIFICANCE: Our results point to different modes of action for N1, N2 and N3, which indicate a great variety of metabolic pathways involved and allow for novel perspectives on the development of trypanocidal agents.

Current drug therapy and pharmaceutical challenges for Chagas disease.

One of the most significant health problems in the American continent in terms of human health, and socioeconomic impact is Chagas disease, caused by the protozoan parasite Trypanosoma cruzi. Infection was originally transmitted by reduviid insects, congenitally from mother to fetus, and by oral ingestion in sylvatic/rural environments, but blood transfusions, organ transplants, laboratory accidents, and sharing of contaminated syringes also contribute to modern day transmission. Likewise, Chagas disease used to be endemic from Northern Mexico to Argentina, but migrations have earned it global. The parasite has a complex life cycle, infecting different species, and invading a variety of cells - including muscle and nerve cells of the heart and gastrointestinal tract - in the mammalian host. Human infection outcome is a potentially fatal cardiomyopathy, and gastrointestinal tract lesions. In absence of a vaccine, vector control and treatment of patients are the only tools to control the disease. Unfortunately, the only drugs now available for Chagas' disease, Nifurtimox and Benznidazole, are relatively toxic for adult patients, and require prolonged administration. Benznidazole is the first choice for Chagas disease treatment due to its lower side effects than Nifurtimox. However, different strategies are being sought to overcome Benznidazole's toxicity including shorter or intermittent administration schedules-either alone or in combination with other drugs. In addition, a long list of compounds has shown trypanocidal activity, ranging from natural products to specially designed molecules, re-purposing drugs commercialized to treat other maladies, and homeopathy. In the present review, we will briefly summarize the upturns of current treatment of Chagas disease, discuss the increment on research and scientific publications about this topic, and give an overview of the state-of-the-art research aiming to produce an alternative medication to treat T. cruzi infection.

Acute Chagas outbreaks: molecular and biological features of Trypanosoma cruzi isolates, and clinical aspects of acute cases in Santander, Colombia.

BACKGROUND: Outbreaks of acute Chagas disease associated with oral transmission are easily detected nowadays with trained health personnel in areas of low endemicity, or in which the vector transmission has been interrupted. Given the biological and genetic diversity of Trypanosoma cruzi, the high morbidity, mortality, and the observed therapeutic failure, new characteristics of these outbreaks need to be addressed at different levels, both in Trypanosoma cruzi as in patient response. The aim of this work was to evaluate the patient's features involved in six outbreaks of acute Chagas disease which occurred in Santander, Colombia, and the characteristics of Trypanosoma cruzi clones isolated from these patients, to establish the potential relationship between the etiologic agent features with host behavior. METHODS: The clinical, pathological and epidemiological aspects of outbreaks were analyzed. In addition, Trypanosoma cruzi clones were biologically characterized both in vitro and in vivo, and the susceptibility to the classical trypanocidal drugs nifurtimox and benznidazole was evaluated. Trypanosoma cruzi clones were genotyped by means of mini-exon intergenic spacer and cytochrome b genes sequencing. RESULTS: All clones were DTU I, and based on the mini-exon intergenic spacer, belong to two genotypes: G2 related with sub-urban, and G11 with rural outbreaks. Girón outbreak clones with higher susceptibility to drugs presented G2 genotype and C/T transition in Cyt b. The outbreaks affected mainly young population (±25.9 years), and the mortality rate was 10 %. The cardiac tissue showed intense inflammatory infiltrate, myocardial necrosis and abundant amastigote nests. However, although the gastrointestinal tissue was congestive, no inflammation or parasites were observed. CONCLUSIONS: Although all clones belong to DTU I, two intra-DTU genotypes were found with the sequencing of the mini-exon intergenic spacer, however there is no strict correlation between genetic groups, the cycles of the parasite or the clinical forms of the disease. Trypanosoma cruzi clones from Girón with higher sensitivity to nifurtimox presented a particular G2 genotype and C/T transition in Cyt b. When the diagnosis was early, the patients responded well to antichagasic treatment, which highlights the importance of diagnosis and treatment early to prevent fatal outcomes associated with these acute episodes.

Trypanocidal effect of the benzyl ester of N-propyl oxamate: a bi-potential prodrug for the treatment of experimental Chagas disease.

BACKGROUND: Chagas disease, which is caused by Trypanosoma cruzi, is a major health problem in Latin America, and there are currently no drugs for the effective treatment of this disease. The energy metabolism of T. cruzi is an attractive target for drug design, and we previously reported that inhibitors of α-hydroxy acid dehydrogenase (HADH)-isozyme II exhibit trypanocidal activity. N-Propyl oxamate (NPOx) is an inhibitor of HADH-isozyme II, and its non-polar ethyl ester (Et-NPOx) is cytotoxic to T. cruzi. A new derivative of NPOx has been developed in this study with higher trypanocidal activity, which could be used for the treatment of Chagas disease. METHODS: The benzyl ester of NPOx (B-NPOx) was synthesized and its activity evaluated towards epimastigotes and bloodstream trypomastigotes (in vitro), as well as mice infected with T. cruzi (in vivo). The activity of B-NPOx was also compared with those of Et-NPOx, benznidazole (Bz) and nifurtimox (Nx). NINOA, Miguz, Compostela, Nayarit and INC-5 T. cruzi strains were used in this study. RESULTS: Polar NPOx did not penetrate the parasites and exhibited no trypanocidal activity. In contrast, the hydrophobic ester B-NPOx exhibited trypanocidal activity in vitro and in vivo. B-NPOx exhibited higher trypanocidal activity than Et-NPOx, Bz and Nx towards all five of the T. cruzi strains. The increased activity of B-NPOx was attributed to its hydrolysis inside the parasites to give NPOx and benzyl alcohol, which is an antimicrobial compound with trypanocidal effects. B-NPOx was also effective against two strains of T. cruzi that are resistant to Bz and Nx. CONCLUSION: B-NPOx exhibited higher in vitro (2- to 14.8-fold) and in vivo (2.2- to 4.5-fold) trypanocidal activity towards T. cruzi than Et-NPOx. B-NPOx also exhibited higher in vitro (2- to 24-fold) and in vivo (1.9- to 15-fold) trypanocidal activity than Bz and Nx. B-NPOx is more lipophilic than Et-NPOx, allowing for better penetration into T. cruzi parasites, where the enzymatic cleavage of B-NPOx would give NPOx and benzyl alcohol, which are potent trypanocidal agents. Taken together with its low toxicity, these results suggest that B-NPOx could be used as a potent prodrug for the treatment of Chagas disease.