nifurtimox and benzonidazole

Chagas disease, caused by the protozoan Trypanosoma cruzi is a neglected tropical disease with high prevalence (5.7 million in Latin America, WHO 2015), significant burden, and significant morbimortality mostly due to severe heart disorders during the chronic phase of infection. Chagas disease is endemic in Latin America, and medical care for the disease is the major expense for Brazil's Universal Healthcare System (Sistema Único de Saúde (SUS). The efficacy of the available drugs benznidazole and nifurtimox are low for the chronic phase of Chagas disease, the phase in which most patients are diagnosed, and there are frequent side effects, and drug resistance occurs. The rapid deployment of new drug regimens that are effective for the chronic phase treatment is low-cost and less toxic than the currently available therapy, which is a global priority. Repurposing drugs already in clinical use with other combinations would be the fastest and safest strategy for treating Chagas disease patients. We hypothesize that the combined treatment using repurposing drugs with benznidazole will be more efficacious than benznidazole alone. This needs to be tested further both in vitro and in animal models to understand the efficacy of the treatment before performing human clinical trials. We further hypothesize that producing nanoparticle formulation of the drugs can reduce their toxicity and improve therapeutic use.

Topics: Animals; Chagas Disease; Drug Repositioning; Humans; Neglected Diseases; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease, caused by Trypanosoma cruzi, is treated with only two drugs; benznidazole and nifurtimox. These drugs have some disadvantages, including their efficacy only in the acute or early infection phases, adverse effects during their use, and the resistance that the parasite has developed to their activity. Therefore, it is necessary to identify new, safe and effective therapeutic alternatives to treat Chagas disease, though governments and the pharmaceutical industry have shown a lack of interest in contributing to this solution. Institutions and research groups on the other hand have worked on some strategies that can help to address the problem. Some of these include the modification of conventional drug dosages, drug repurposing, and combined therapy. Plants and derived compounds with antiparasitic effects have also been studied, taking advantage of traditional medicinal knowledge. Others have studied the parasite to identify essential genes that can be used as therapeutic targets to design new, targeted drugs. Some of these studies have generated promising results, but few reach clinical phase studies. Institutions and research groups should be encouraged to unify efforts and cover all aspects of drug development according to resources and knowledge availability. In the end, this exchange of knowledge would lead to the development of new therapeutic alternatives to treat Chagas disease and benefit the populations it affects.

Topics: Animals; Chagas Disease; Drug Development; Drug Resistance; Humans; Medicine, Traditional; Molecular Targeted Therapy; Nifurtimox; Nitroimidazoles; Plant Preparations; Trypanocidal Agents; Trypanosoma cruzi

Despite more than 100 years since it was firstly described Chagas disease, only two drugs are available to treat Chagas disease: Nifurtimox launched by Bayer in 1965 and benznidazole launched by Roche in 1971. Drug discovery initiatives have been looking for new compounds as an alternative to these old drugs. Although new platforms have been used with the latest technologies, a critical step on that process still relies on the in vivo model. Unfortunately, to date, available animal models have limited predictive value and there is no standardization. With the aim to better understand the role of benznidazole, the current standard of care of Chagas disease, we performed this review. We intend to analyze the influence of the experimental design of the most used animal model, the murine model, in the assessment of the efficacy endpoint.

Topics: Animals; Chagas Disease; Disease Models, Animal; Dose-Response Relationship, Drug; Humans; Mice; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease is a neglected disease that remains a public health threat, particularly in Latin America. The most important treatment options are nitroimidazole derivatives, such as nifurtimox and benznidazole (BZN). Some studies suggest that for adults seropositive to T. cruzi but without clinically evident chronic Chagas cardiomyopathy (CCC), a simple fixed-dose scheme of BZN could be equivalent to a weight-adjusted dose. We compared the efficacy and safety of a fixed dose of BZN with an adjusted dose for T. cruzi seropositive adults without CCC. We used the Cochrane methods, and reported according to the PRISMA statement. We included randomized controlled trials (RCTs) allocating participants to fixed and/or adjusted doses of BZN for T. cruzi seropositive adults without CCC. We searched (December 2019) Cochrane, MEDLINE, EMBASE, LILACS, Clinicaltrials.gov, and International Clinical Trials Registry Platform (ICTRP), and contacted Chagas experts. Selection, data extraction, and risk of bias assessment, using the Cochrane tool, were performed independently by pairs of reviewers. Discrepancies were solved by consensus within the team. Primary outcomes were parasite-related outcomes and efficacy or patient-related safety outcomes. We conducted a meta-analysis using RevMan 5.3 software and used GRADE summary of finding tables to present the certainty of evidence by outcome. We identified 655 records through our search strategy and 10 studies (four of them ongoing) met our inclusion criteria. We did not find any study directly comparing fixed vs adjusted doses of BZN, however, some outcomes allowed subgroup comparisons between fixed and adjusted doses of BZN against placebo. Moderate-certainty evidence suggests no important subgroup differences for positive PCR at one year and for three safety outcomes (drug discontinuation, peripheral neuropathy, and mild rash). The same effect was observed for any serious adverse events (low-certainty evidence). All subgroups showed similar effects (I2 0% for all these subgroup comparisons but 32% for peripheral neuropathy), supporting the equivalence of BZN schemes. We conclude that there is no direct evidence comparing fixed and adjusted doses of BZN. Based on low to very low certainty of evidence for critical clinical outcomes and moderate certainty of evidence for important outcomes, fixed and adjusted doses may be equivalent in terms of safety and efficacy. An individual patient data network meta-analysis could bette

Topics: Adult; Cardiomyopathies; Chagas Disease; Databases, Factual; Humans; Nifurtimox; Nitroimidazoles; Patient Safety; Randomized Controlled Trials as Topic; Treatment Outcome; Triazoles; Trypanosoma cruzi

People with Chagas disease may develop progressive and lethal heart conditions. Drugs to eliminate the parasite Trypanosoma cruzi (T cruzi) currently carry limited therapeutic value and are used in the early stages of the disease. Extending the use of these drugs to treat chronic chagasic cardiomyopathy (CCC) has also been proposed.. To assess the benefits and harms of nitrofurans and trypanocidal drugs for treating late-stage, symptomatic Chagas disease and CCC in terms of blood parasite reduction or clearance, mortality, adverse effects, and quality of life.. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and LILACS databases on 12 November 2019. We also searched two clinical trials registers, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), on 3 December 2019.. We included randomised controlled trials (RCTs) assessing trypanocidal drugs versus placebo or no treatment for late-stage, symptomatic Chagas disease and CCC.. We conducted the reporting of the review according the standard Cochrane methods. Two review authors independently retrieved articles, performed data extraction, and assessed risk of bias. Any disagreements were resolved by a third review author. We contacted study authors for additional information.. We included two studies in this review update. One RCT randomly assigned 26 participants to benznidazole 5 mg/kg/day; 27 participants to nifurtimox 5 mg/kg/day; and 24 participants to placebo for 30 days. The second RCT, newly included in this update, randomised 1431 participants to benznidazole 300 mg/day for 40 to 80 days and 1423 participants to placebo. We also identified one ongoing study. Benznidazole compared to placebo At five-year follow-up, low quality of the evidence suggests that there may be a benefit of benznidazole when compared to placebo for clearance or reduction of antibody titres (risk ratio (RR) 1.25, 95% confidence interval (CI) 1.14 to 1.37; 1 trial; 1896 participants). We are uncertain about the effects of benznidazole for the clearance of parasitaemia demonstrated by negative xenodiagnosis, blood culture, and/or molecular assays due to very limited evidence. Low quality of the evidence suggests that when compared to placebo, benznidazole may make little to no difference in the risk of heart failure (RR 0.89, 95% CI 0.69 to 1.14; 1 trial; 2854 participants) and ventricular tachycardia (RR 0.80, 95% CI 0.51 to 1.26; 1 trial; 2854 participants). We found moderate quality of the evidence that adverse events increase with benznidazole when compared to placebo (RR 2.52, 95% CI 2.09 to 3.03; 1 trial; 2854 participants). Adverse effects were observed in 23.9% of patients in the benznidazole group compared to 9.5% in the placebo group. The most frequent adverse effects were: cutaneous rash, gastrointestinal symptoms, and peripheral polyneuropathy. No data were available for the outcomes of pathological demonstration of tissue parasites and quality of life. Nifurtimox compared to placebo Data were only available for this comparison for the outcome clearance or reduction of antibody titres, and we are uncertain about the effect due to very limited evidence. Regarding adverse events, one RCT mentioned in a general manner that nifurtimox caused intense adverse events, without any quantification.. There is insufficient evidence to support the efficacy of the trypanocidal drugs benznidazole and nifurtimox for late-stage, symptomatic Chagas disease and CCC.

Topics: Chagas Cardiomyopathy; Chagas Disease; Chronic Disease; Humans; Nifurtimox; Nitroimidazoles; Parasitemia; Placebos; Randomized Controlled Trials as Topic; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease, caused by infection with the parasite Trypanosoma cruzi, represents a huge public health problem in the Americas, where millions of people are affected. Despite the availability of two drugs against the infection (benznidazole and nifurtimox), multiple factors impede their effective usage: (1) gaps in patient and healthcare provider awareness; (2) lack of access to diagnosis; (3) drug toxicity and absence of treatment algorithms to address adverse effects; (4) failures in drug supply and distribution; and (5) inconsistent drug efficacy against the symptomatic chronic stage. Areas covered: We review new approaches and technologies to enhance access to diagnosis and treatment to reduce the disease burden. We also provide an updated picture of recently published and ongoing anti-T. cruzi drug clinical trials. Although there has been progress improving the research and development (R&D) landscape, it is unclear whether any new treatments will emerge soon. Literature search methodologies included multiple queries to public databases and the use of own-built libraries. Expert opinion: Besides R&D, there is a major need to continue awareness and advocacy efforts by patient associations, local and national governments, and international agencies. Overall, health systems strengthening is essential to ensure vector control commitments, as well as patient access to diagnosis and treatment.

Topics: Chagas Disease; Health Services Accessibility; Humans; Latin America; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Neglected tropical diseases (NTDs) constitute a group of infectious diseases prevalent in countries with tropical and subtropical climate that affect the poorest individuals and produce high chronic disability associated with serious problems for the health system and socioeconomic development. Chagas disease or American trypanosomiasis is included on the NTDs list. However, even though this disease affects more than 10 million people, mostly in Latin America, causing the death of over 10,000 people every year, only two drugs are approved for its treatment, benznidazole and nifurtimox. These antiparasitic agents were developed almost half a century ago and present several biopharmaceutical disadvantages such as low aqueous solubility and permeability limiting their bioavailability. In addition, both therapeutic agents are available only as tablets and a liquid pediatric formulation is still lacking. Therefore, novel pharmaceutical strategies to optimize the pharmacotherapy of Chagas disease are urgently required. In this regard, nanotechnological approaches may be a crucial alternative for the delivery of both drugs ensuring an effective pharmacotherapy although the successful bench-to-bedside translation remains a major challenge. The present work reviews in detail the formulation and in-vitro/in-vivo analysis of different nanoformulations of nifurtimox and benznidazole in order to enhance their solubility, dissolution, bioavailability and trypanocidal activity.

Topics: Chagas Disease; Dosage Forms; Humans; Nanostructures; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. It is a significant public health problem, affecting millions of people worldwide. And although it was described 110 years ago, only two old nitroheterocyclic drugs, benznidazole and nifurtimox, are currently available for the treatment of Chagas disease and both have several limitations. Besides the clear unmet medical need, many challenges preclude the development of new treatments, some of them related to a lack of understanding of the pathophysiology of the disease and parasite-host interactions. New knowledge and tools are becoming available, but the number of new chemical entities progressing through the preclinical pipeline is inadequate. Therefore, it is still uncertain whether safe, effective and accessible new drugs will be available in the near future. The Chagas disease research community must commit to even greater collaboration to ensure that patients eventually benefit from better treatments.

Topics: Chagas Disease; Drug Discovery; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease has become a global health problem due to migration of infected people out of Latin America to non-endemic countries. For more than 40 years, only the nitroimidazole compounds Benznidazole and Nifurtimox, have been used for specific treatment of Trypanosoma cruzi infection with disappointing results, specially due to the long duration of treatment and adverse events in the chronic phase. In the last years, ergosterol inhibitors have been also proposed for specific treatment. Different randomized clinical trials were performed for evaluating their treatment efficacy and safety. One of the greatest concerns in clinical trials is to provide an early surrogate biomarker of response to trypanocidal chemotherapy. Serological response is slow and the classical parasitological tests have poor sensitivity and are time-consuming. Nowadays, PCR is the most helpful tool for assessing treatment response in a short period of time. Different protocols of PCR have been developed, being quantitative real time PCR based on amplification of repetitive satellite or minicircle DNA sequences plus an internal amplification standard, the mostly employed strategies in clinical trials. Standardized protocols and the use of an external quality assessment ensure adequate technical procedures and reliable data. Clinical trials have shown a significant reduction in parasite loads, reaching undetectable DNA levels in bloodstream after specific treatment, however events of treatment failure have also been reported. Treatment failure could be due to inadequate penetrance of the drugs into the affected tissues, to the presence of primary or secondary drug resistance of the infecting strains as well as to the existence of dormant parasite variants reluctant to drug action. The early diagnosis of drug resistance would improve clinical management of Chagas disease patients, allowing dictating alternative therapies with a combination of existing drugs or new anti-T. cruzi agents. The aim of this review was to describe the usefulness of detecting T.cruzi DNA by means of real time PCR assays, as surrogate biomarker in clinical trials for evaluating new drugs for CD or new regimens of available drugs and the possibility to detect treatment failure.

Topics: Biomarkers; Chagas Disease; Chronic Disease; Drug Resistance; Humans; Nifurtimox; Nitroimidazoles; Nucleic Acids; Parasite Load; Real-Time Polymerase Chain Reaction; Treatment Failure; Treatment Outcome; Trypanocidal Agents; Trypanosoma cruzi

The genetic diversity of Trypanosoma cruzi, the protozoan agent of Chagas disease, is widely recognized. At present, T. cruzi is partitioned into seven discrete typing units (DTUs), TcI-TcVI and Tcbat. This article reviews the present knowledge on the parasite population structure, the evolutionary relationships among DTUs and their distinct, but not exclusive ecological and epidemiological associations. Different models for the origin of hybrid DTUs are examined, which agree that genetic exchange among T. cruzi populations is frequent and has contributed to the present parasite population structure. The geographic distribution of the prevalent DTUs in humans from the southern United States to Argentina is here presented and the circumstantial evidence of a possible association between T. cruzi genotype and Chagas disease manifestations is discussed. The available information suggests that parasite strains detected in patients, regardless of the clinical presentation, reflect the principal DTU circulating in the domestic transmission cycles of a particular region. In contrast, in several orally transmitted outbreaks, sylvatic strains are implicated. As a consequence of the genotypic and phenotypic differences of T. cruzi strains and the differential geographic distribution of DTUs in humans, regional variations in the sensitivity of the serological tests are verified. The natural resistance to benznidazole and nifurtimox, verified in vivo and in vitro for some parasite stocks, is not associated with any particular DTU, and does not explain the marked difference in the anti-parasitic efficacy of both drugs in the acute and chronic phases of Chagas disease. Throughout this review, it is emphasized that the interplay between parasite and host genetics should have an important role in the definition of Chagas disease pathogenesis, anti-T. cruzi immune response and chemotherapy outcome and should be considered in future investigations.

Topics: Animals; Argentina; Biological Evolution; Chagas Disease; Drug Resistance; Genetic Variation; Genotype; Humans; Nifurtimox; Nitroimidazoles; Serologic Tests; Trypanosoma cruzi

Although Chagas disease is a rare entity in North America, it is associated with significant cardiac morbidity. It is estimated that 20-30% of those who are infected will eventually develop cardiovascular disease secondary to Chagas disease. We review the literature and share our experience on the surgical management of this challenging patient population.

Topics: Cardiac Surgical Procedures; Chagas Cardiomyopathy; Echocardiography; Female; Heart Aneurysm; Heart Ventricles; Humans; Magnetic Resonance Imaging; Middle Aged; Nifurtimox; Nitroimidazoles; Serologic Tests; Stroke Volume; Treatment Outcome; Trypanocidal Agents

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.

Topics: Antiparasitic Agents; Chagas Disease; Drug Discovery; Humans; Nifurtimox; Nitroimidazoles; Parasitic Sensitivity Tests; Trypanosoma cruzi

Chagas disease (CD) is caused by the protozoan parasite

Topics: Animals; Chagas Disease; Chronic Disease; Clinical Trials as Topic; Disease Models, Animal; Drug Compounding; Humans; Incidence; Latin America; Nanoparticles; Nifurtimox; Nitroimidazoles; Observational Studies as Topic; Randomized Controlled Trials as Topic; Tissue Distribution; Trypanocidal Agents; Trypanosoma cruzi

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.

Topics: Americas; Chagas Disease; Humans; Life Cycle Stages; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

A conservative estimation indicates that more than 400 000 Latin American immigrants are living in Italy. Several studies have shown that among these, the prevalence of Chagas disease is between 3.9% and 17%, so it is not unlikely to find a patient with this disease during a cardiology visit. How many patients from Latin America are diagnosed with heart failure in Italy and no one has ever thought about a possible Chagas disease? This brief review describes the situation of the disease in Italy, its characteristics, the etiology of this disease and its treatment. The latter aspect will be discussed considering the recent published results of the BENEFIT study, where it was found that treatment with benznidazole in patients with Chagas' cardiomyopathy is able to reduce significantly the detection of parasites in the blood, but it is not able to prevent clinical deterioration during 5 years of follow-up. The possible implications of these results will be discussed.

Topics: Chagas Cardiomyopathy; Chagas Disease; Emigrants and Immigrants; Humans; Italy; Neglected Diseases; Nifurtimox; Nitroimidazoles; Prevalence; South America; Treatment Outcome; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease or American trypanosomiasis is a neglected tropical disease caused by the parasite Trypanosoma cruzi. Although the number of infected individuals has decreased, about 6-7 million people are infected worldwide. The chemotherapy drugs currently used are limited to benznidazole and nifurtimox. They are effective in acute phase, congenital transmission and children with chronic infection; however, recent clinical trials have shown limitations in adults with chronic infection, presenting drawbacks during the treatment. Thus, there is an urgent need for new effective, safe and affordable drugs to fight against this complex disease. There were high expectations for azole derivatives as they appeared to be the most promising drugs for the treatment of Chagas disease during the last decade; however, the disappointing results obtained so far in clinical trials evidenced the lack of correlation between preclinical and clinical development. Therefore, the feedback obtained from these studies should define the starting point for addressing a roadmap for the drug discovery process in the fight against this disease. To tackle this challenge, it is important to keep in mind the drug target profile, already defined by panels of experts, and the coordinated work involving multi-disciplinary networks focusing not only on the discovery of new drugs but also on the standardization of the protocols that would allow acceleration in the Chagas disease drug discovery process.

Topics: Chagas Disease; Clinical Trials as Topic; Drug Discovery; Humans; Nifurtimox; Nitroimidazoles; Real-Time Polymerase Chain Reaction; RNA, Protozoan; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease is caused by the flagellate protozoan Trypanosoma cruzi (T. cruzi). It is endemic in Latin American countries outside the Caribbean. The current criterion for cure in the chronic phase of the disease is the negativization of at least two serological tests such as enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence assay (IIF) and indirect hemagglutination assay (IHA). The serological evolution of treated subjects with chronic T. cruzi infection is variable. Treatment failure is indicated by a positive parasitological and/or molecular test (persistence of parasitemia).. To summarize the pattern of response to treatment of parasitological, molecular and serological tests performed during the follow-up of subjects with chronic T. cruzi infection.. Electronic searches in relevant databases and screening of citations of potentially eligible articles were accomplished. Organizations focusing on neglected infectious diseases were asked for help in identifying relevant studies. Included studies were randomized controlled trials (RCTs), quasi-RCTs, and cohort studies involving adults and children with chronic infection who received trypanocidal treatment (benznidazole or nifurtimox) and were followed over time. The assessment of risk of bias was performed separately for each study design. The Cochrane Collaboration's tool and the guidelines developed by Hayden et al. were used. Two reviewers extracted all data independently. A third review author was consulted in case of discordant opinion. Additional analyses were defined in ad-hoc basis. Scatter plots for percentage of positive parasitological and molecular tests and for negative serological tests were developed by using the lowess curve technique. Heterogeneity was measured by I2. The protocol was registered in PROSPERO, an international prospective register of systematic review protocols (Registration Number CRD42012002162).. Out of 2,136 citations screened, 54 studies (six RCTs and 48 cohort studies) were included. The smoothed curves for positive xenodiagnosis and positive polymerase chain reaction (PCR) were characterized by a sharp decrease at twelve month posttreatment. Afterwards, they reached 10-20% and 40% for xenodiagnosis and PCR, respectively. The smoothed curves for negative conventional serological tests increased up to 10% after 48 months of treatment. In the long-term, the rate of negativization was between 20% and 45%. The main sources of bias identified across cohort studies were the lack of control for confounding and attrition bias. In general, RCTs were judged as low risk of bias in all domains. The level of heterogeneity across included studies was moderate to high. Additional analysis were incomplete because of the limited availability of data. In this regard, the country of origin of study participants might affect the results of parasitological and molecular tests, while the level of risk of bias might affect serological outcomes. Subgroup analysis suggested that seronegativization occurs earlier in children compared to adults.. We acknowledge that there is a dynamic pattern of response based on parasitological, molecular and serological tests in subjects chronically infected with T. cruzi after treatment. Our findings suggest a trypanocidal effect in the long-term follow-up. Further research is needed to explore potential sources of heterogeneity and to conduct reliable subgroup analysis.

Topics: Adult; Antibodies, Protozoan; Chagas Disease; Child; Chronic Disease; Cohort Studies; Disease Progression; DNA, Protozoan; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique, Indirect; Follow-Up Studies; Hemagglutination Tests; Humans; Nifurtimox; Nitroimidazoles; Parasitemia; Randomized Controlled Trials as Topic; Treatment Failure; Trypanocidal Agents; Trypanosoma cruzi; Xenodiagnosis

In the last decades, increasing international migration and travel from Latin America to Europe have favoured the emergence of tropical diseases outside their "historical" boundaries. Chagas disease, a zoonosis endemic in rural areas of Central and South America represents a clear example of this phenomenon. In the absence of the vector, one of the potential modes of transmission of Chagas disease in non-endemic regions is through blood and blood products. As most patients with Chagas disease are asymptomatic and unaware of their condition, in case of blood donation they can inadvertently represent a serious threat to the safety of the blood supply in non-endemic areas. Since the first cases of transfusion-transmitted Chagas disease were described in the last years, non-endemic countries began to develop ad hoc strategies to prevent and control the spread of the infection. United States, Spain, United Kingdom and France first recognised the need for Trypanosoma cruzi screening in at-risk blood donors. In this review, we trace an up-to-date perspective on Chagas disease, describing its peculiar features, from epidemiological, pathological, clinical and diagnostic points of view. Moreover, we describe the possible transmission of Chagas disease through blood or blood products and the current strategies for its control, focusing on non-endemic areas.

Topics: Adult; Blood Donors; Blood Safety; Chagas Disease; Donor Selection; Emigration and Immigration; Enzyme-Linked Immunosorbent Assay; Europe; Female; Global Health; Health Services Needs and Demand; Humans; Infant, Newborn; Latin America; Male; Mass Screening; Nifurtimox; Nitroimidazoles; North America; Parasitemia; Pregnancy; Pregnancy Complications, Infectious; Transfusion Reaction; Travel; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease is the highest impact parasitic disease in the Americas but often goes untreated due to the shortcomings of currently available therapeutics. Thus there is an urgent need for new treatment options and growing interest in drug development for the infection. This review summarizes some of the recent advances and failures in this realm, with particular emphasis on recently published studies and unpublished results presented at a recent Chagas Drug Discovery Consortium meeting.

Topics: Chagas Disease; Clinical Trials as Topic; Drug Discovery; Drug Therapy, Combination; Humans; Nifurtimox; Nitroimidazoles; Sterols; Trypanocidal Agents; Trypanosoma cruzi

For years, Chagas disease treatment has been limited to only two drugs of highly questionable and controversial use (Nifurtimox(®) and Benznidazole(®)). In the search of effective drugs, many efforts have been made, but only a few structures have emerged as actual candidates. Heading into this, the multitarget-directed approach appears as the best choice. In this framework, indazoles were shown to be potent Trypanosoma cruzi growth inhibitors, being able to lead both the formation of reactive oxygen species and the inhibition of trypanothione reductase. Herein, we discuss the main structural factors that rule the anti-T. cruzi properties of indazoles, and how they would be involved in the biological properties as well as in the action mechanisms, attempting to make parallels between the old paradigms and current evidences in order to outline what could be the next steps to follow in regard to the future drug design for Chagas disease treatment.

Topics: Chagas Disease; Drug Design; Humans; Indazoles; NADH, NADPH Oxidoreductases; Nifurtimox; Nitroimidazoles; Protozoan Proteins; Reactive Oxygen Species; Trypanocidal Agents; Trypanosoma cruzi

Immunosuppression, which has become an increasingly relevant clinical condition in the last 50 years, modifies the natural history of Trypanosoma cruzi infection in most patients with Chagas disease. The main goal in this setting is to prevent the consequences of reactivation of T. cruzi infection by close monitoring. We analyze the relationship between Chagas disease and three immunosuppressant conditions, including a description of clinical cases seen at our center, a brief review of the literature, and recommendations for the management of these patients based on our experience and on the data in the literature. T. cruzi infection is considered an opportunistic parasitic infection indicative of AIDS, and clinical manifestations of reactivation are more severe than in acute Chagas disease. Parasitemia is the most important defining feature of reactivation. Treatment with benznidazole and/or nifurtimox is strongly recommended in such cases. It seems reasonable to administer trypanocidal treatment only to asymptomatic immunosuppressed patients with detectable parasitemia, and/or patients with clinically defined reactivation. Specific treatment for Chagas disease does not appear to be related to a higher incidence of neoplasms, and a direct role of T. cruzi in the etiology of neoplastic disease has not been confirmed. Systemic immunosuppressive diseases or immunosuppressants can modify the natural course of T. cruzi infection. Immunosuppressive doses of corticosteroids have not been associated with higher rates of reactivation of Chagas disease. Despite a lack of evidence-based data, treatment with benznidazole or nifurtimox should be initiated before immunosuppression where possible to reduce the risk of reactivation. Timely antiparasitic treatment with benznidazole and nifurtimox (or with posaconazole in cases of therapeutic failure) has proven to be highly effective in preventing Chagas disease reactivation, even if such treatment has not been formally incorporated into management protocols for immunosuppressed patients. International consensus guidelines based on expert opinion would greatly contribute to standardizing the management of immunosuppressed patients with Chagas disease.

Topics: Adult; Antiprotozoal Agents; Chagas Disease; Female; Humans; Immunocompromised Host; Male; Middle Aged; Nifurtimox; Nitroimidazoles; Opportunistic Infections; Triazoles; Trypanosoma cruzi

Hundred years after the discovery of Chagas' disease, there is a lack of effective treatment to control this neglected disease caused by the parasite Trypanosoma cruzi. The transmission is primarily through vector-borne blood transfusion or during pregnancy, producing high mortality and morbidity among poor people in many countries of Latin America. In the last decades, the efforts have been focused mainly on the elimination of vectors. At the same time, screening of blood donors in order to avoid transfusional transmission has been improved all over the world. However, Chagas' disease is still a major public health problem, with estimates of nearly 90 million people at risk of infection and more than eight million infected in 18 endemic countries. Despite the high incidence in endemic regions and the dissemination of neglected diseases in North America and Europe, to date, there are only two drugs developed and prescribed for the treatment of Chagas' disease, nifurtimox (tablets of 120 mg) and benzonidazole (tablets of 100 mg). In this review, different approaches carried out in the last decades for developing novel pharmaceutical formulations for the delivery of nifurtimox and benznidazole are discussed.

Topics: Animals; Chagas Disease; Drug Delivery Systems; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease, also known as American trypanosomiasis, is a chronic infection caused by Trypanosoma cruzi, a protozoan parasite. It is transmitted to human beings mainly through the feces of infected triatomine bugs. The disease affects an estimated 8 to 10 million people in the Americas, putting them at risk of developing life-threatening cardiac and gastrointestinal complications. This article provides a brief update on the epidemiology, clinical manifestations, diagnosis, and treatment of Chagas disease.

Topics: Chagas Disease; Chronic Disease; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease affects 7.7 million people and 28 million people are at risk of acquiring the disease in 15 endemic countries of Latin America. Benznidazole and nifurtimox are drugs that have been used to treat the disease. However, both drugs induce severe side effects. Treatment with benznidazole has been recommended for the acute phase (0-4 months after infection), recent chronic phase (children 0-14 years of age, treated 4 months after infection) and congenital infection. Average cure rates for Chagas disease patients obtained from clinical trials were 97.9% (congenital infection, treatment performed 0-6 months of age), 71.5% (acute phase), 57.6% (recent chronic phase, children 0-13 years of age) and 5.9% (late chronic phase, great majority of patients between 15 and 69 years of age). Clinical evidence about the capacity of antiparasitic treatment to avoid, stop or revert heart pathology in indeterminate and cardiac chronic patients is contradictory. The investigation of novel therapeutic strategies against Chagas disease remains a priority in the research of tropical diseases. Unfortunately, Chagas disease remains neglected in the formulation of strategies toward control of this disease. This article focuses on current therapeutic approaches to Chagas disease.

Topics: Adult; Animals; Chagas Disease; Child; Clinical Trials as Topic; Drug Administration Schedule; Humans; Latin America; Mice; Myocarditis; Nifurtimox; Nitroimidazoles; Survival Analysis; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease and African sleeping sickness are trypanosomal infections that represent important public health problems in Latin America and Africa, respectively. The restriction of these diseases to the poorer parts of the world has meant that they have been largely neglected and limited progress has been made in their treatment. The nitroheterocyclic prodrugs nifurtimox and benznidazole, in use against Chagas disease for >40 years, remain the only agents available for this infection. In the case of African sleeping sickness, nifurtimox has recently been added to the arsenal of medicines, with the nitroheterocycle fexinidazole currently under evaluation. For a long time, the cytotoxic mechanism of these drugs was poorly understood: nifurtimox was thought to act via production of superoxide anions and nitro radicals, while the mode of benznidazole action was more obscure. The trypanocidal activity of nitroheterocyclic drugs is now known to depend on a parasite type I nitroreductase (NTR). This enzyme is absent from mammalian cells, a difference that forms the basis for the drug selectivity. The role of this enzyme in drug activation has been genetically and biochemically validated. It catalyses the 2-electron reduction of nitroheterocyclic compounds within the parasite, producing toxic metabolites without significant generation of superoxide. Recognition that this enzyme is responsible for activation of nitroheterocyclic prodrugs has allowed screening for compounds that preferentially target the parasite. This approach has led to the identification of two new classes of anti-trypanosomal agents, nitrobenzylphosphoramide mustards and aziridinyl nitrobenzamides, and promises to yield new, safer, more effective drugs.

Topics: Africa; Animals; Benzamides; Chagas Disease; Humans; Insect Vectors; Latin America; Nifurtimox; Nitro Compounds; Nitroimidazoles; Nitroreductases; Phosphoramide Mustards; Prodrugs; Protozoan Proteins; Trypanocidal Agents; Trypanosoma brucei brucei; Trypanosoma cruzi; Trypanosomiasis, African

Topics: Adult; Animals; Chagas Cardiomyopathy; Chagas Disease; Chronic Disease; Disease Progression; Electrocardiography; Female; Humans; Life Cycle Stages; Nifurtimox; Nitroimidazoles; Practice Guidelines as Topic; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease must be treated in all its stages: acute, indeterminate, chronic, and initial and middle determinant chronic, due to the fact that DNA of the parasite can be demonstrated by PCR in chronic cases, where optical microscopy does not detect parasites. Nifurtimox (NF) and benznidazole (BNZ) are the drugs accepted to treat humans based upon ethical considerations and efficiency. However, both the drugs produce secondary effects in 30% of the cases, and the treatment must be given for at least 30-60 days. Other useful drugs are itraconazole and posaconazole. The latter may be the drug to treat Chagas disease in the future when all the investigations related to it are finished. At present, there is no criterion of cure for chronic cases since in the majority, the serology remains positive, although it may decrease. In acute cases, 70% cure with NF and 75% with BNZ is achieved. In congenital cases, 100% cure is obtained if the treatment is performed during the first year of life. In chronic acquired cases, 20% cure and 50% improvement of the electrocardiographic changes are obtained with itraconazole.

Topics: Acute Disease; Animals; Chagas Disease; Chronic Disease; Humans; Nifurtimox; Nitroimidazoles; Time Factors; Treatment Outcome; Trypanocidal Agents

There are approximately 7.8 million people in Latin America, including Chile, who suffer from Chagas disease and another 28 million who are at risk of contracting it. Chagas is caused by the flagellate protozoan Trypanosoma cruzi. It is a chronic disease, where 20%-30% of infected individuals develop severe cardiopathy, with heart failure and potentially fatal arrhythmias. Currently, Chagas disease treatment is more effective in the acute phase, but does not always produce complete parasite eradication during indeterminate and chronic phases. At present, only nifurtimox or benznidazole have been proven to be superior to new drugs being tested. Therefore, it is necessary to find alternative approaches to treatment of chronic Chagas. The current treatment may be rendered more effective by increasing the activity of anti-Chagasic drugs or by modifying the host's immune response. We have previously shown that glutathione synthesis inhibition increases nifurtimox and benznidazole activity. In addition, there is increasing evidence that cyclooxygenase inhibitors present an important effect on T. cruzi infection. Therefore, we found that aspirin reduced the intracellular infection in RAW 264.7 cells and, decreased myocarditis extension and mortality rates in mice. However, the long-term benefit of prostaglandin inhibition for Chagasic patients is still unknown.

Topics: Acute Disease; Animals; Chagas Cardiomyopathy; Chagas Disease; Chronic Disease; Cyclooxygenase 1; Cyclooxygenase 2; Humans; Mice; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease is a neglected parasitic disease endemic in the Americas. It mainly affects impoverished populations and the acute phase of the infection mostly affects children. Many cases have also been detected in nonendemic countries as a result of recent migratory trends. The chronic phase is relatively asymptomatic, but 30% of patients with chronic infection eventually develop cardiac and digestive complications that commonly lead to death or disability. Only two drugs are available for the treatment of Chagas disease, benznidazole and nifurtimox. These drugs have been shown to be effective in the treatment of both acute and early chronic phases in children, but the pharmacokinetics of these drugs have never been studied in this population. We have set out to conduct a pharmacokinetics study of benznidazole in a pediatric population with Chagas disease. The results of this study are expected to allow better estimation of the optimal doses and schedule of pharmacotherapy for Chagas disease in children.

Topics: Argentina; Chagas Cardiomyopathy; Chagas Disease; Child; Drug Administration Schedule; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

It is estimated that over 300,000 people with Chagas disease are living in the USA, with more than 30,000 cases of Chagas cardiomyopathy expected per year. The epidemiology of Chagas disease in Central and South America differs from that of the USA, where particular attention must focus on blood bank screening, organ donation and vertical transmission. It is essential that healthcare practitioners have heightened awareness of Chagas disease in the differential diagnosis of certain patients and are aware of recommendations for the management of these patients in the USA. Ongoing attention must focus on trials that determine whether all patients will benefit from treatment as well as studies of new agents for therapy.

Topics: Chagas Disease; Guidelines as Topic; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi; United States

Chagas disease is a significant public health problem in the Americas, despite efforts to decrease the number of new cases since 1990. Etiologic treatment of the disease's chronic phase is still controversial.. We reviewed the strongest studies to evaluate the drugs used in the acute and chronic disease phases, with emphasis on benznidazole.. A Medline search using the keywords 'Chagas disease' and 'treatment,' with no date limitations, was performed.. Study methods in completed trials varied greatly, with none being a randomized, double-blind, placebo-controlled study. The only trial using these methods is still ongoing. The treatment in acute phase is the major indication, but during chronic phase doubts still remain.. Only patients in the acute phase of Chagas disease (whatever their age; including children and adolescents) who are treated have good outcomes, although the criteria defining 'cure' remain controversial.

Topics: Adolescent; Adult; Chagas Disease; Child; Humans; Middle Aged; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

Current knowledge of the biochemistry of Trypanosoma cruzi has led to the development of new drugs and the understanding of their mode of action. Some trypanocidal drugs such as nifurtimox and benznidazole act through free radical generation during their metabolism. T. cruzi is very susceptible to the cell damage induced by these metabolites because enzymes scavenging free radicals are absent or have very low activities in the parasite. Another potential target is the biosynthetic pathway of glutathione and trypanothione, the low molecular weight thiol found exclusively in trypanosomatids. These thiols scavenge free radicals and participate in the conjugation and detoxication of numerous drugs. Inhibition of this key pathway could render the parasite much more susceptible to the toxic action of drugs such as nifurtimox and benznidazole without affecting the host significantly. Other drugs such as allopurinol and purine analogs inhibit purine transport in T. cruzi, which cannot synthesize purines de novo. Nitroimidazole derivatives such as itraconazole inhibit sterol metabolism. The parasite's respiratory chain is another potential therapeutic target because of its many differences with the host enzyme complexes. The pharmacological modulation of the host's immune response against T. cruzi infection as a possible chemotherapeutic target is discussed. A large set of chemicals of plant origin and a few animal metabolites active against T. cruzi are enumerated and their likely modes of action are briefly discussed.

Topics: Acute-Phase Reaction; Animals; Chagas Disease; Ergosterol; Host-Parasite Interactions; Humans; Immunologic Factors; Mammals; Nifurtimox; Nitric Oxide; Nitroimidazoles; Purines; Sulfhydryl Compounds; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease (American trypanosomiasis) is endemic in 21 countries of the Americas, where control is largely focused on elimination of the domestic insect vectors (Triatominae) coupled with measures to extend and improve the screening of blood donors in order to avoid tranfusional transmission. Through national programmes and multinational initiatives coordinated by WHO-PAHO, much has been accomplished in these domains in terms of reducing transmission. Attention now turns to consolidating the successes in interrupting transmission, and improved treatment for those already infected and those who may become affected in the future. This article, based on technical discussions at the "Epidemiological and Sociological Determinants of Chagas Disease, Basic Information to Establish a Surveillance and Control Policy " meeting in Rio de Janeiro, is designed to open the debate on appropriate strategies for continuation of the successful initiatives against Chagas disease.

Topics: Chagas Disease; Health Services Accessibility; Humans; International Cooperation; Nifurtimox; Nitroimidazoles; Pan American Health Organization; Trypanocidal Agents

Chagas disease, an infection caused by a protozoan parasite and previously endemic to Mexico and Central and South America, is becoming more prevalent in the United States and Canada. Because nurses and physicians in health care settings may be the first to encounter undiagnosed cases of Chagas disease, it is essential that public health personnel and health care providers in general become more familiar with the disease, including its incidence and prevalence, clinical manifestations, diagnostic criteria, treatment options, and implications for nursing.

Topics: Acute Disease; Animals; Canada; Chagas Disease; Chronic Disease; Emigration and Immigration; Hispanic or Latino; Humans; Immunologic Tests; Incidence; Insect Control; Insect Vectors; Nifurtimox; Nitroimidazoles; Nurse's Role; Prevalence; Primary Prevention; Risk Factors; South America; Travel; Triatoma; Trypanocidal Agents; United States

Chagas' disease (American trypanosomiasis) is an endemic parasitic disease in some areas of Latin America. About 16-18 million persons are infected with the aetiological agent of the disease, Trypanosoma cruzi, and more than 100 million are living at risk of infection. There are different modes of infection: (1) via blood sucking vector insects infected with T. cruzi, accounting for 80-90% of transmission of the disease; (2) via blood transfusion or congenital transmission, accounting for 0.5-8% of transmission; (3) other less common forms of infection, eg, from infected food or drinks or via infected organs used in transplants. The acute phase of the disease can last from weeks to months and typically is asymptomatic or associated with fever and other mild nonspecific manifestations. However, life-threatening myocarditis or meningoencephalitis can occur during the acute phase. The death rate for persons in this phase is about 10%. Approximately 10-50% of the survivors develop chronic Chagas' disease, which is characterized by potentially lethal cardiopathy and megacolon or megaoesophagus. There are two drugs available for the aetiological treatment of Chagas' disease: nifurtimox (Nfx) and benznidazole (Bz). Nfx is a nitrofurane and Bz is a nitroimidazole compound. The use of these drugs to treat the acute phase of the disease is widely accepted. However, their use in the treatment of the chronic phase is controversial. The undesirable side effects of both drugs are a major drawback in their use, frequently forcing the physician to stop treatment. The most frequent adverse effects observed in the use of Nfx are: anorexia, loss of weight, psychic alterations, excitability, sleepiness, digestive manifestations such as nausea or vomiting, and occasionally intestinal colic and diarrhoea. In the case of Bz, skin manifestations are the most notorious (e.g., hypersensitivity, dermatitis with cutaneous eruptions, generalized oedema, fever, lymphoadenopathy, articular and muscular pain), with depression of bone marrow, thrombocytopenic purpura and agranulocytosis being the more severe manifestations. Experimental toxicity studies with Nfx evidenced neurotoxicity, testicular damage, ovarian toxicity, and deleterious effects in adrenal, colon, oesophageal and mammary tissue. In the case of Bz, deleterious effects were observed in adrenals, colon and oesophagus. Bz also inhibits the metabolism of several xenobiotics biotransformed by the cytochrome P450 system and it

Topics: Animals; Chagas Disease; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

People with Chagas disease (American Trypanosomiasis) may develop progressive and potentially lethal heart conditions. Drugs to eliminate the causative parasite, Trypanosoma cruzi, currently in use have limited therapeutic value and are used in early stages of the disease. Extending the use of these drugs to treat symptomatic chronic parasitism with chronic Chagasic cardiopathy (CCC) and progressive dilated cardiomyopathy has been proposed.. To assess the effects (harms and benefits) of nitrofurans and imidazolic trypanocidal drugs for treating late stage chronic Chagas disease and CCC.. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (Issue 3, 2004), MEDLINE (1985-2004), EMBASE (1985-2004), BIREME (1985-2004), LILACS (1985-2004), ARTEMISA (1985-2004), SCIELO (1985-2004). Indexing terms in English and Spanish were used. References obtained were assessed for relevance by two reviewers independently.. We included randomized controlled clinical trials (RCTs), single or double blind using trypanocidal drugs versus placebo or no treatment in CCC.. All articles retrieved were assessed using a predefined check list to determine if they met the inclusion criteria. Two independent reviewers collected data using a pre-designed form piloted on three articles before the review process started. Disagreements were resolved by a third reviewer. If the information was unavailable the articles were excluded. We planned a quantitative analysis of reduction of parasite load whether recorded as a categorical variable or the reduction of specific antibody titers. However insufficient data were available for quantitative analysis. We prepared a qualitative description of data identified.. We found only one randomized double blind placebo controlled trial. We also found six uncontrolled or non-randomized studies which were of some relevance and were therefore described. We found insufficient evidence to define the effects of drug treatment for people with CCC.. There is insufficient evidence to support the efficacy of nitrofurans or imidazolic drugs as recommended treatment in CCC and chronic T.cruzi infections, specifically if overt heart disease is present. A well designed randomized controlled trial is necessary to establish if new drugs are suitable for treatment of cardiac patients with CCC.

Topics: Chagas Cardiomyopathy; Chagas Disease; Chronic Disease; Clinical Trials as Topic; Humans; Imidazoles; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

Chagas' disease is a major parasitic problem in developing countries in Central and South America. Chemotherapy for such disease is still insufficient and not effective in its chronic part. Many efforts have been made in recent years to know more about possible new biochemical targets to design new selective drugs. This paper reviews old therapeutic approaches -Nifurtimox, Benznidazole and related compounds- and the latest rationally developed drugs that prove to be active against different parasitic forms.

Topics: Animals; Chagas Disease; Drug Design; Enzyme Inhibitors; Humans; Nifurtimox; Nitroimidazoles; Phosphoenolpyruvate Carboxykinase (ATP); Reducing Agents; Trypanocidal Agents; Trypanosoma cruzi

In this "Critical Review" we made a historical introduction of drugs assayed against Chagas disease beginning in 1912 with the works of Mayer and Rocha Lima up to the experimental use of nitrofurazone. In the beginning of the 70s, nifurtimox and benznidazole were introduced for clinical treatment, but results showed a great variability and there is still a controversy about their use for chronic cases. After the introduction of these nitroheterocycles only a few compounds were assayed in chagasic patients. The great advances in vector control in the South Cone countries, and the demonstration of parasite in chronic patients indicated the urgency to discuss the etiologic treatment during this phase, reinforcing the need to find drugs with more efficacy and less toxicity. We also review potential targets in the parasite and present a survey about new classes of synthetic and natural compounds studied after 1992/1993, with which we intend to give to the reader a general view about experimental studies in the area of the chemotherapy of Chagas disease, complementing the previous papers of Brener (1979) and De Castro (1993).

Topics: Chagas Disease; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

Topics: Animals; Chagas Disease; Gentian Violet; Humans; Insect Vectors; Nifurtimox; Nitroimidazoles; Toxicology; Trypanocidal Agents

An effective treatment for Trypanosoma cruzi infection has been investigated, since the 30s. The goals of the specific treatment against T. cruzi infection are, at the individual level, to eliminate the parasite, and to reduce the probability of developing Chagas disease. At the end of the 60s and at the beginning of the 70s, two compounds were clinically investigated in Argentina: Nifurtimox and Benznidazole. After the approval by the Ministry of Health, in 1983 the first guidelines for the treatment of T. cruzi infection were proposed and approved. These guidelines recommended the treatment of cases in the acute phase. Due to the publication of new information in support of the utility of these drugs for treating cases in the indeterminate phase of Chagas disease, in 1997 the original guidelines were revised and new procedures were approved. At present, the treatment is recommended for: 1) all patients undergoing the acute phase; 2) children and young people undergoing the indeterminate phase; 3) adult patients undergoing the indeterminate phase or with incipient heart lesions; 4) laboratory accidents and during surgery, and 5) organ transplant recipients or donors. The general clinical laboratory control is needed for the intra-treatment monitoring of the patient. Titration of specific antibodies with monospecific antigens has been shown to be an adequate marker of therapeutic efficacy.

Topics: Adult; Argentina; Chagas Disease; Child; Drug Administration Schedule; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

The chemotherapy of Chagas' disease remains an unsolved problem, and the search for alternative drugs continues. Only two nitroheterocyclic drugs are in clinical use at the present time, and these have severely restricted applicability for chronic patients, as well as being highly toxic. This review covers drugs tested in the last 12 years. A large number of different compounds have been assayed in a variety of ways, most commonly in terms of their capacity to inhibit epimastigote proliferation. Allopurinol has emerged for the treatment of chronic cases. However, only with greater knowledge of the biochemistry of the parasite and in particular of its peculiarities, will it be possible to shift the emphasis of drug research away from random screenings onto a more rational footing. This is exemplified by recent studies carried out using purine derivatives and trypanothione reductase inhibitors.

Topics: Animals; Anti-Bacterial Agents; Azoles; Chagas Disease; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease, caused by the protozoan parasite, Trypanosoma cruzi, is a major source of morbidity and death in Latin America. Many infected immigrants from that region now reside in the United States, posing a risk of transfusion-associated transmission of the organism. Serologic testing is the cornerstone of diagnosing chronic T. cruzi infections, and improved assays are needed. Drug treatment is problematic because the two available drugs can have severe side effects and lack efficacy. T. cruzi infection can be particularly severe in immunosuppressed patients.

Topics: Animals; Chagas Disease; Heart; Humans; Immunocompromised Host; Interferon-gamma; Laboratory Infection; Mice; Nifurtimox; Nitroimidazoles; Recombinant Proteins; Trypanocidal Agents; Trypanosoma cruzi; United States

American trypanosomiasis (Chagas' disease) is an endemic parasitic disease afflicting more than 20 million persons in Latin America. Two drugs are currently being used for treatment of the acute phase of Chagas' disease: 4-[(5-nitrofurfurylidene)amino-3-methylthiomorpholine-1,1-di oxide] (Nifurtimox; Nfx) and (N-benzl-2-nitro-1-imidazole acetamide) (Benznidazole; Bz). Nfx and Bz have serious undesirable effects, which have been reported during their clinical use, including anorexia and weight loss, nausea and vomiting, nervous excitation, insomnia, psyche depressions, convulsions, vertigo, headache, sleepiness, myalgias, arthralgias, loss of balance, disorientation, forgetfulness, paresthesias, adynamia, acoustic phenomena, peripheral neuropathies, gastralgia, mucosal edema, hepatic intolerance, skin manifestations, and intolerance to drinking alcohol. Effects in the central and peripheral nervous system of Nfx were also reproduced in animals. Signs of testicular and ovarian injury were reported for both Nfx and Bz, the effects of Bz being in general less intense than those of Nfx. Both drugs evidenced mutagenicity. In light of the present knowledge about the toxicity of Nfx and Bz, further studies on the mutagenic, teratogenic, carcinogenic, and reproductive effects of both drugs are recommended. Lack of information is particularly serious for Bz. Studies on Nfx and Bz biotransformation, activation to reactive metabolites, and potential mechanisms for their toxic effects were analyzed. Risk-benefit considerations of the use of Nfx and Bz were made and an analysis of the need for research on Chagas' disease chemotherapy was also performed.

Topics: Chagas Disease; Humans; Latin America; Nifurtimox; Nitrofurans; Nitroimidazoles

Topics: Allopurinol; Animals; Free Radicals; Gentian Violet; Glutathione; Humans; Nifurtimox; Nitroimidazoles; Oxidation-Reduction; Trypanocidal Agents; Trypanosoma cruzi

In recent years it has been apparent that many of the known antiparasitic drugs produce free radicals. Intracellular reduction followed by autooxidation yielding O.-2 and H2O2 has been suggested as the mode of action of nifurtimox on Trypanosoma cruzi and as the basis of its toxicity in mammals. On the other hand, free radical intermediates that do not generate oxygen-reduction products under physiological conditions have been found in the metabolic pathways of other antiparasitic nitro compounds (benznidazole, metronidazole, and other 5-nitroimidazoles) used in the treatment of diseases such as Chagas' disease, trichomoniasis, giardiasis, balantidiasis, amebiasis, and schistosomiasis. In these cases, as well as in the case of niridazole (used in the treatment of schistosomiasis), covalent binding or other interactions of the intermediates of nitroreduction with parasite macromolecules are possibly involved in their toxicity. Redox cycling of these compounds under aerobic conditions appears to be a detoxification reaction by inhibiting net reduction of the drugs.

Topics: Animals; Chemical Phenomena; Chemistry; Free Radicals; Hydrogen Peroxide; Macromolecular Substances; Metronidazole; Nifurtimox; Niridazole; Nitro Compounds; Nitroimidazoles; Oxidation-Reduction; Parasitic Diseases; Schistosoma mansoni; Superoxides; Tritrichomonas; Trypanosoma cruzi

Topics: Chagas Disease; Gentian Violet; Humans; Melarsoprol; Nifurtimox; Nitroimidazoles; Pentamidine; Suramin; Trypanocidal Agents; Trypanosomiasis, African

Either benznidazole (BZN) or nifurtimox (NFX) is recommended as equivalent to treat Trypanosoma cruzi infection. Nonetheless, supportive data from randomised trials is limited to individuals treated with BZN in southern cone countries of Latin America.. The goal of this randomised, concealed, blind, parallel-group trial is to inform the trypanocidal efficacy and safety of NFX and its equivalence to BZN among individuals with T. cruzi positive serology (TC+). Eligible individuals are TC+, 20-65 years old, with no apparent symptoms/signs or uncontrolled risk factors for cardiomyopathy and at negligible risk of re-infection. Consenting individuals (adherent to a 10-day placebo run-in phase) receive a 120-day BID blinded treatment with NFX, BZN or matching placebo (2:2:1 ratio). The four active medication arms include (1) a randomly allocated sequence of 60-day, conventional-dose (60CD) regimes (BZN 300 mg/day or NFX 480 mg/day, ratio 1:1), followed or preceded by a 60-day placebo treatment, or (2) 120-day half-dose (120HD) regimes (BZN 150 mg/day or NFX 240 mg/day, ratio 1:1). The primary efficacy outcome is the proportion of participants testing positive at least once for up to three polymerase chain reaction (PCR) assays (1 + PCR) 12-18 months after randomisation. A composite safety outcome includes moderate to severe adverse reactions, consistent blood marker abnormalities or treatment abandons. The trial outside Colombia (expected to recruit at least 60% of participants) is pragmatic; it may be open-label and not include all treatment groups, but it must adhere to the randomisation and data administration system and guarantee a blinded efficacy outcome evaluation. Our main comparisons include NFX groups with placebo (for superiority), NFX versus BZN groups and 60CD versus 120HD groups (for non-inferiority) and testing for the agent-dose and group-region interactions. Assuming a 1 + PCR ≥ 75% in the placebo group, up to 25% among BZN-treated and an absolute difference of up to ≥ 25% with NFX to claim its trypanocidal effect, 60-80 participants per group (at least 300 from Colombia) are needed to test our hypotheses (80-90% power; one-sided alpha level 1%).. The EQUITY trial will inform the trypanocidal effect and equivalence of nitroderivative agents NFX and BZN, particularly outside southern cone countries. Its results may challenge current recommendations and inform choices for these agents.. ClinicalTrials.gov, NCT02369978 . Registered on 24 February 2015.

Topics: Adult; Aged; Asymptomatic Diseases; Chagas Disease; Colombia; Female; Humans; Male; Middle Aged; Multicenter Studies as Topic; Nifurtimox; Nitroimidazoles; Randomized Controlled Trials as Topic; Therapeutic Equivalency; Time Factors; Treatment Outcome; Trypanocidal Agents; Trypanosoma cruzi; Young Adult

Laboratory and animal studies have demonstrated that pyrazolopyrimidines have significant activity against Trypanosoma cruzi. This clinical investigation was to ascertain the efficacy of allopurinol in the treatment of chronic Chagas' disease. Of 307 patients studied, 91 were untreated; the remaining 216 were divided into 4 treatment groups. These corresponded to 600 or 900 mg/day of allopurinol for 60 days and benznidazole or nifurtimox at conventional dosage regimens. Patients were evaluated clinically, serologically, and parasitologically. Allopurinol was found to be as efficacious as the conventional therapeutic modalities in eliminating the parasitemia and rendering patients seronegative. Adverse reactions occurred in 11% of patients who received allopurinol and in 30% of those receiving nitrofurans. Reactions with the conventional therapy were more frequent and of a more serious nature. Oral allopurinol is as effective as the nitrofurans, but has none of the side effects.

Topics: Adult; Allopurinol; Chagas Disease; Chronic Disease; Clinical Trials as Topic; Female; Humans; Male; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

Topics: Animals; Cats; Chagas Disease; Clinical Trials as Topic; Cricetinae; Dogs; Guinea Pigs; Humans; Mice; Nifurtimox; Nitrofurans; Nitroimidazoles; Rats; Trypanocidal Agents; Trypanosoma cruzi

Topics: Allopurinol; Chagas Cardiomyopathy; Chagas Disease; Chronic Disease; Clinical Trials as Topic; Female; Humans; Male; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

Chagas disease, caused by the protozoan Trypanosoma cruzi, is a serious chronic parasitic disease, currently treated with Nifurtimox (NFX) and Benznidazole (BZ). In addition to high toxicity, these drugs have low healing efficacy, especially in the chronic phase of the disease. The existence of drug-resistant T. cruzi strains and the occurrence of cross-resistance between BZ and NFX have also been described. In this context, it is urgent to study the metabolism of these drugs in T. cruzi, to better understand the mechanisms of resistance. Prostaglandin F2α synthase (PGFS) is an enzyme that has been correlated with parasite resistance to BZ, but the mechanism by which resistance occurs is still unclear. Our results show that the genome of the CL Brener clone of T. cruzi, contains five PGFS sequences and three potential pseudogenes. Using CRISPR/Cas9 we generated knockout cell lines in which all PGFS sequences were disrupted, as shown by PCR and western blotting analyses. The PGFS deletion did not alter the growth of the parasites or their susceptibility to BZ and NFX when compared to wild-type (WT) parasites. Interestingly, NTR-1 transcripts were shown to be upregulated in ΔPGFS mutants. Furthermore, the ΔPGFS parasites were 1.6 to 1.7-fold less tolerant to oxidative stress generated by menadione, presented lower levels of lipid bodies than the control parasites during the stationary phase, and were less infective than control parasites.

Topics: Chagas Disease; Dinoprost; Humans; Nifurtimox; Oxidative Stress; Trypanocidal Agents; Trypanosoma cruzi; Vitamin K 3

Parasite persistence after acute infection with Trypanosoma cruzi is an important factor in the development of Chagas disease (CD) cardiomyopathy. Few studies have investigated the clinical effectiveness of CD treatment through the evaluation of cardiological events by long term follow-up of treated children. Cardiological evaluation in children is challenging since features that would be diagnosed as abnormal in an adult's ECG may be normal, age-related findings in a pediatric ECG trace. The objective was to evaluate cardiac involvement in patients with Chagas disease with a minimum follow-up of 6 years post-treatment.. A descriptive study of a cohort of pediatric patients with CD treated with benznidazole (Bz) or nifurtimox (Nf) was conducted. Children (N = 234) with at least 6 years post CD treatment followed at the Parasitology and Chagas Service, Buenos Aires Children's Hospital (Argentina) were enrolled. By convenience sampling, children who attended a clinical visit between August 2015 and November 2019 were also invited to participate for additional cardiovascular studies like 24-hour Holter monitoring and speckle-tracking 2D echocardiogram (STE). Benznidazole was prescribed in 171 patients and nifurtimox in 63 patients. Baseline parasitemia data was available for 168/234 patients. During the follow-up period, alterations in routine ECG were observed in 11/234 (4.7%, 95% CI [2-7.4%]) patients. In only four patients, with complete right bundle branch block (cRBBB) and left anterior fascicular block (LAFB), ECG alterations were considered probably related to CD. During follow-up, 129/130 (99%) treated patients achieved persistent negative parasitemia by qPCR. Also decrease in T.cruzi antibodies titers was observed in all patients and negative seroconversion occurred in 123/234 (52%) patients.. A low incidence of cardiological lesions related to CD was observed in patients treated early for pediatric CD. This suggests a protective effect of parasiticidal treatment on the development of cardiological lesions and highlights the importance of early treatment of infected children.. ClinicalTrials.gov NCT04090489.

Topics: Adult; Cardiology; Chagas Cardiomyopathy; Chagas Disease; Child; Humans; Nifurtimox; Nitroimidazoles; Parasitemia; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease is caused by

Topics: Animals; Chagas Disease; Isoenzymes; Mice; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease remains a significant public health problem in Latin America. There are only two chemotherapy drugs, nifurtimox and benznidazole, and both may have severe side effects. After complete chemotherapy of acute cases, seropositive diagnosis may revert to negative. However, there are no definitive parasitological or serological biomarkers of cure.. Following a pilot study with seven Bolivian migrants to Spain, we tested 71 serum samples from chronic patients (mean age 12.6 years) inhabiting the Argentine Chaco region. Benznidazole chemotherapy (5-8 mg/kg day, twice daily for 60 days) was administered during 2011-2016. Subsequently, pre-and post-chemotherapy serum samples were analysed in pairs by IgG1 and IgG ELISA using two different antigens and Chagas Sero K-SeT rapid diagnostic tests (RDT). Molecular diagnosis by kDNA-PCR was applied to post-treatment samples.. Pilot data demonstrated IgG1 antibody decline in three of seven patients from Bolivia 1 year post-treatment. All Argentine patients in 2017 (averaging 5 years post-treatment), except one, were positive by conventional serology. All were kDNA-PCR-negative. Most (91.5%) pre-treatment samples were positive by the Chagas Sero K-SeT RDT, confirming the predominance of TcII/V/VI. IgG1 and IgG of Argentine patients showed significant decline in antibody titres post-chemotherapy, with either lysate (IgG, P = 0.0001, IgG1, P = 0.0001) or TcII/V/VI peptide antigen (IgG, P = 0.0001, IgG1, P = 0.0001). IgG1 decline was more discriminative than IgG. Antibody decline after treatment was also detected by the RDT. Incomplete treatment was associated with high IgG1 post-treatment titres against lysate (P = 0.013), as were IgG post-treatment titres to TcII/V/VI peptide (P = 0.0001). High pre-treatment IgG1 with lysate was associated with Qom ethnicity (P = 0.045). No associations were found between gender, age, body mass index and pre- or post-treatment antibody titres.. We show that following chemotherapy of early chronic Chagas disease, significant decline in IgG1 antibody suggests cure, whereas sustained or increased IgG1 is a potential indicator of treatment failure. Due to restricted sensitivity, IgG1 should not be used as a diagnostic marker but has promise, with further development, as a biomarker of cure. We show that following chemotherapy of early chronic Chagas disease, a significant decline in IgG1 antibody suggests cure, whereas sustained or increased IgG1 is a potential indicator of treatment failure. Due to restricted sensitivity, IgG1 should not be used as a diagnostic marker but has promise, with further development, as a biomarker of cure.

Topics: Adolescent; Antibodies, Protozoan; Chagas Disease; Chronic Disease; Cohort Studies; Female; Humans; Immunoglobulin G; Immunologic Tests; Male; Molecular Diagnostic Techniques; Nifurtimox; Nitroimidazoles; Pilot Projects; Time Factors; Trypanocidal Agents; Trypanosoma cruzi

The immunodominant B13 protein of Trypanosoma cruzi is found on the surface of trypomastigotes and exhibits cross-reactivity with the human cardiac myosin heavy chain; for which antibodies against this parasitic antigen may be involved in the development of disease pathology. In a cohort of chronically T. cruzi-infected adults, undergoing trypanocidal treatment, or not, we, therefore, decided to evaluate the levels of anti-B13 antibodies (ELISA-B13) and its eventual relationship with heart complaints. Two hundred twenty-eight serum samples from 76 chronically infected adults with an average follow-up of 24 years were analyzed. Thirty of them had received trypanocidal treatment. Among treated patients, anti-B13 Ab levels in successive samples showed a significant decrease in reactivity as the years after treatment increased (ANOVA test, p = 0.0049). At the end of the follow-up, 36.7% became non-reactive for ELISA B13. Untreated patients did not have significant variations in the level of anti-B13 antibodies during follow-up. None of the treated patients had electrocardiographic changes compatible with chronic chagasic cardiomyopathy, whereas 21.7% of those undergoing no treatment did show such kind of pathological electrocardiogram tracings. ELISA-B13 was reactive in all cases with heart involvement. Among untreated patients, there were no significant differences in anti-B13 antibodies when comparing individuals without proven pathology with those with chronic chagasic cardiomyopathy. Although treatment with trypanocidal drugs was followed by decreased anti-B13 antibody levels, such assessment was unhelpful in differentiating the evolution of chronic chagasic heart disease.

Topics: Adult; Animals; Antibodies, Protozoan; Antigens, Protozoan; Argentina; Chagas Disease; Chronic Disease; Cross Reactions; Enzyme-Linked Immunosorbent Assay; Female; Follow-Up Studies; Humans; Male; Nifurtimox; Nitroimidazoles; Retrospective Studies; Trypanocidal Agents; Trypanosoma cruzi; Young Adult

Drug combinations have been evaluated for Chagas disease in an attempt to improve efficacy and safety. In this line, the objective of this work is to assess the effects of treatment with nitro drugs combinations using benznidazole (BZ) or nifurtimox (NFX) plus the sulfone metabolite of fexinidazole (fex-SFN) in vitro and in vivo on Trypanosoma cruzi infection. The in vitro interaction of fex-SFN and BZ or NFX against infected H9c2 cells by the Y strain was classified as an additive (0.5⩾ΣFIC<4), suggesting the possibility of a dose reduction in the in vivo T. cruzi infection. Next, the effect of combining suboptimal doses was assessed in an acute model of murine T. cruzi infection. Drug combinations led to a faster suppression of parasitemia than monotherapies. Also, the associations led to higher cure levels than those in the reference treatment BZ 100 mg day−1 (57.1%) (i.e. 83.3% with BZ/fex-SFN and 75% with NFX/fex-SFN). Importantly, toxic effects resulting from the associations were not observed, according to weight gain and hepatic enzyme levels in the serum of experimental animals. Taken together, this study is a starting point to explore the potential effects of nitro drugs combinations in preclinical models of kinetoplastid-related infections.

Topics: Animals; Chagas Disease; Drug Therapy, Combination; Female; Humans; Inhibitory Concentration 50; Mice; Neglected Diseases; Nifurtimox; Nitro Compounds; Nitroimidazoles; Real-Time Polymerase Chain Reaction; Sulfones

Current options for Chagas' disease treatment are restricted to benznidazole and nifurtimox. To the best of our knowledge, no study has ever compared their tolerance in adults in a non-endemic country.. To compare the completion rates and drug tolerance in a cohort of patients treated according to current guidelines.. We analysed the medical records of all Chagas' disease patients aged 18 years or over who started antiparasitic treatment at the Geneva University Hospitals, Switzerland, from 2008 to 2016. We recorded treatment duration and all adverse events.. We included 176 patients, 92 and 84 of whom received benznidazole or nifurtimox, respectively. The overall treatment completion rate was 62.5%, without a significant difference between the groups (P=0.436). Most patients (89.8%) suffered at least one adverse event. Those receiving nifurtimox had more events (6.2 versus 3.5, P<0.001). Mucocutaneous symptoms predominated in the benznidazole group, whereas digestive symptoms were most frequent with nifurtimox. Neuropsychiatric events frequently occurred in both groups, most notably in patients receiving nifurtimox. Arthralgia, dyspnoea, sensitive neuropathy and pruritus were independent predictors of treatment interruption.. Currently recommended drug regimens for Chagas' disease are not well tolerated and entail frequent treatment discontinuation irrespective of the drug used. This highlights the need to improve treatment tolerance in adults with Chagas' disease with new therapeutic options.

Topics: Adult; Chagas Disease; Chronic Disease; Drug Tolerance; Humans; Nifurtimox; Nitroimidazoles; Switzerland; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease is caused by infection with the parasite Trypanosoma cruzi, which might lead to a chronic disease state and drive to irreversible damage to the heart and/or digestive tract tissues. Endemic in 21 countries in the Americas, it is the neglected disease with a highest burden in the region. Current estimates point at ~6 million people infected, of which ~30% will progress onto the symptomatic tissue disruptive stage. There is no vaccine but there are two anti-parasitic drugs available: benznidazole and nifurtimox. However, their efficacy is variable at the chronic symptomatic stage and both have frequent adverse effects. Since there are no prognosis markers, drugs should be administered to all T. cruzi-infected individuals in the indeterminate and early symptomatic stages. Nowadays, there are no tests-of-cure either, which greatly undermines patients follow-up and the search of safer and more efficacious drugs. Therefore, the identification and validation of biomarkers of disease progression and/or treatment response on which to develop tests of prognosis and/or cure is a major research priority. Both parasite- and host-derived markers have been investigated. In the present manuscript we present an updated outlook of the latter.

Topics: Biomarkers; Chagas Disease; Chronic Disease; Gastrointestinal Tract; Heart; Host-Parasite Interactions; Humans; Nifurtimox; Nitroimidazoles; Prognosis; Treatment Outcome; Trypanosoma cruzi

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.

Topics: Analysis of Variance; Genotype; Lethal Dose 50; Nifurtimox; Nitroimidazoles; Paraguay; Phenotype; Triazoles; Trypanocidal Agents; Trypanosoma cruzi

Trypanosoma cruzi has three distinct life cycle stages; epimastigote, trypomastigote, and amastigote. Amastigote is the replication stage in host mammalian cells, hence this stage of parasite has clinical significance in drug development research. Presence of extracellular amastigotes (EA) and their infection capability have been known for some decades. Here, we demonstrate that EA can be utilized as an axenic culture to aid in stage-specific study of T. cruzi. Amastigote-like property of axenic amastigote can be sustained in LIT medium at 37°C at least for 1 week, judging from their morphology, amastigote-specific UTR-regulated GFP expression, and stage-specific expression of selected endogenous genes. Inhibitory effect of benznidazole and nifurtimox on axenic amastigotes was comparable to that on intracellular amastigotes. Exogenous nucleic acids can be transfected into EA via conventional electroporation, and selective marker could be utilized for enrichment of transfectants. We also demonstrate that CRISPR/Cas9-mediated gene knockout can be performed in EA. Essentiality of the target gene can be evaluated by the growth capability of the knockout EA, either by continuation of axenic culturing or by host infection and following replication as intracellular amastigotes. By taking advantage of the accessibility and sturdiness of EA, we can potentially expand our experimental freedom in studying amastigote stage of T. cruzi.

Topics: Antiprotozoal Agents; Clustered Regularly Interspaced Short Palindromic Repeats; CRISPR-Associated Protein 9; Electroporation; Gene Expression; Gene Knockout Techniques; Genetics, Microbial; Molecular Biology; Nifurtimox; Nitroimidazoles; Parasitic Sensitivity Tests; Trypanosoma cruzi

Topics: Allopurinol; Animals; Cell Line; Chagas Disease; Humans; Mice; Mortality; Nifurtimox; Nitroimidazoles; Real-Time Polymerase Chain Reaction; Trypanosoma cruzi

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.. 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".. 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.. Even if great findings were reported, more efforts are necessary to find new therapies against Trypanosoma cruzi (T. cruzi).

Topics: Chagas Disease; Drug Repositioning; Humans; Molecular Structure; Nifurtimox; Nitroimidazoles; Prognosis; Trypanocidal Agents; Trypanosoma cruzi

Only benznidazole (Bnz) (1) and nifurtimox (Nfx) (2) are licensed for the treatment of Chagas disease although their safety and efficacy profile are far from ideal. Farmanguinhos from Fiocruz has developed seven nitroimidazole compounds (4-10) analogs of megazol (3).. To evaluate whether the genotoxic effect of 3 was abolished in the seven nitroimidazoles (4-10) analogs using the in vitro alkaline comet assay (CA) and the in vitro cytokinesis-block micronucleus assay (CBMN) in whole human blood cells (WHBC) and correlate this effect with their trypanocidal activity using bloodstream trypomastigote forms of Trypanosoma cruzi.. The toxicity of 3-10 to WHBC in the in vitro CA was determined using the fluorescein diacetate/ethidium bromide assay. DNA damage in the in vitro CA was evaluated according to tail size in four classes (0-3) and methyl methane-sulfonate (MMS) was used as a positive control. The cytotoxicity of 3-10 to WHBC in the CBMN was measured using the cytokinesis-block proliferation index and the replication index. The number of the micronucleate cells in 2,000 binucleate cells by experimental group was determined. Mitomycin C and N-deacetyl-N-methylcolchicine were used as positive controls.. Compound 3 showed a significant DNA strand break effect through the in vitro CA and highly significant clastogenic and/or aneugenic effect in the CBMN. Compounds 5, 6, 8, 9 and 10 showed negative results in the CBMN and positive results in the in vitro CA, while the inverse effect was observed for 4 and 7.. Compound 10 was the most promising to proceed with the development as a drug candidate in the treatment of Chagas disease showing absence of chromosomal cytogenetic damage and high activity against T. cruzi, about two times higher than 3 and the clinical drug 1.

Topics: Blood Cells; Cell Survival; Comet Assay; DNA Damage; Humans; Micronucleus Tests; Nifurtimox; Nitroimidazoles; Reference Values; Reproducibility of Results; Thiadiazoles; Time Factors; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease is a tropical illness caused by the protozoan

Topics: Animals; Cell Line; Cell Proliferation; Chagas Disease; Coloring Agents; Humans; Methylene Blue; Nifurtimox; Nitroimidazoles; Phenothiazines; Tolonium Chloride; Trypanocidal Agents; Trypanosoma cruzi

Although many Trypanosoma cruzi (T. cruzi) strains isolated from a wide range of hosts have been characterized, there is a lack of information about biological features from vertically transmitted strains. We describe the molecular and biological characteristics of the T. cruzi VD strain isolated from a congenital Chagas disease patient. The VD strain was typified as DTU TcVI; in vitro sensitivity to nifurtimox (NFX) and beznidazole (BZ) were 2.88 μM and 6.19 μM respectively, while inhibitory concentrations for intracellular amastigotes were 0.24 μM for BZ, and 0.66 μM for NFX. Biological behavior of VD strain was studied in a mouse model of acute infection, resulting in high levels of parasitemia and mortality with a rapid clearence of bloodstream trypomastigotes when treated with BZ or NFX, preventing mortality and reducing parasitic load and intensity of inflammatory infiltrate in skeletal and cardiac muscle. Treatment-induced parasitological cure, evaluated after immunossupression were 41% and 35% for BZ and NFX treatment respectively, suggesting a partial response to these drugs in elimination of parasite burden. This exhaustive characterization of this T. cruzi strain provides the basis for inclusion of this strain in a panel of reference strains for drug screening and adds a new valuable tool for the study of experimental T. cruzi infection.

Topics: Animals; Brain; Chagas Disease; Chlorocebus aethiops; Disease Models, Animal; DNA, Protozoan; Female; Heart; Humans; Infant; Infectious Disease Transmission, Vertical; Inhibitory Concentration 50; Male; Mice; Mice, Inbred BALB C; Muscle, Skeletal; Myocardium; Nifurtimox; Nitroimidazoles; Parasitemia; Random Allocation; Trypanocidal Agents; Trypanosoma cruzi; Vero Cells

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.

Topics: Animals; Cell Line; Cell Survival; Chagas Disease; Male; Mice; Nifurtimox; Nitroimidazoles; Triazoles; Trypanocidal Agents; Trypanosoma cruzi

To describe the tolerability and rate of nifurtimox discontinuation when administered as a second-line treatment to patients with previous treatment interruptions due to adverse reactions with benznidazole.. We studied a prospective cohort study of adult patients with chronic Chagas disease in a referral centre in Spain treated from July 2007 to July 2017. We analysed the tolerability profile and treatment interruption rate due to adverse reactions (ARs) to nifurtimox in patients previously incompletely treated (less than 30 days) with benznidazole due to ARs.. A total of 472 patients initiated treatment with benznidazole during the study period. Of these, 118 (25%) developed ARs that led to treatment discontinuation before 30 days of therapy. Fifty-three (44.9%) of 118 initiated nifurtimox as second-line treatment; most were women (79.3%), were of Bolivian origin (98.1%) and had a median age of 37.3 years (interquartile range, 29.8-43.2). The most common ARs with nifurtimox were cutaneous hypersensitivity (24.1%), digestive disorders (22.2%), fever (12.9%), neurologic disturbances (11.1%), depression, anxiety or insomnia (9.2%), dyspnoea (7.4%), myalgia (5.5%), and dizziness, asthenia or malaise (7.4%). Twenty-six (49.1%) of 53 patients discontinued nifurtimox due to ARs, all of them before the required minimal therapy duration of 60 days. There were no deaths.. Treatment of chronic Chagas disease relies on two drugs with a poor tolerability profile. In our cohort, 12.3% of the patients who initiated benznidazole and subsequently nifurtimox in case of nontolerance developed ARs that led to permanent treatment discontinuation. Most were women of childbearing age, a group for whom therapy has the added benefit of interrupting vertical transmission.

Topics: Adult; Chagas Disease; Chronic Disease; Cohort Studies; Drug Tolerance; Drug-Related Side Effects and Adverse Reactions; Female; Humans; Male; Nifurtimox; Nitroimidazoles; Prospective Studies; Retreatment; Trypanosoma cruzi

Chagas disease is a parasite infection primarily transmitted to humans via the bite of triatomine insect vectors. Up to 8 million people are estimated to be infected with Chagas disease in the Americas. Patients who do not receive treatment can develop severe cardiac debility, gastrointestinal organ dysfunction, and may die. The changing demographics of the United States, a consequence of changing immigration patterns, means that healthcare providers are more likely to encounter patients with Chagas disease, and must understand its cause, pathogenesis, diagnosis, and treatment.

Topics: Acute-Phase Reaction; Cardiomyopathies; Chagas Disease; Chronic Disease; Diagnosis, Differential; Female; Humans; Male; Megacolon; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi; United States

Topics: Chagas Disease; Follow-Up Studies; HIV Infections; Humans; Immunocompetence; Immunocompromised Host; Nifurtimox; Nitroimidazoles; Treatment Outcome; Trypanocidal Agents

Describe a tool to estimate demand for benznidazole and nifurtimox to treat Chagas disease, and report on its implementation in a group of Latin American countries.. The project was carried out in the following stages: 1) development of a tool to estimate demand, and definition of the evaluation and decision variables to estimate demand 2) data collection via a questionnaire completed by representatives of control programs, complemented with data from the literature; 3) presentation of the tool, followed by validation, and adaptation by representatives of the control programs in order to plan drug procurement for 2012 and 2013; and 4) further analysis of the obtained data, especially regarding benznidazole, and comparison of country estimates.. Fourteen endemic countries of Latin America took part in the third stage, and a consolidated estimate was made. The number of estimated treatments, based on the number of tablets per treatment established in the regimen of reference was: 867 in the group under 1 year of age; 2 042 835 in the group from 1 to 15 years old; 2 028 in the group from 15 to 20 years old; and 10 248 in adults over 20. This means that it is possible to provide benznidazole to less than 1% of people for whom treatment is indicated.. The development and systematic use of demand management tools can play a key role in helping to provide access to the anti-Chagas drugs. There is a significant gap between the projected demand for drugs and current estimates of prevalence rates.

Topics: Adolescent; Adult; Chagas Disease; Child; Child, Preschool; Humans; Infant; Latin America; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Young Adult

Drugs for neglected tropical diseases (NTD) are being excessively priced in the United States. Benznidazole, the first-line drug for Chagas disease, may become approved by the Food and Drug Administration (FDA) and manufactured by a private company in the US, thus placing it at risk of similar pricing. Chagas disease is an NTD caused by Trypanosoma cruzi; it is endemic to Latin America, infecting 8 million individuals. Human migration has changed the epidemiology causing nonendemic countries to face increased challenges in diagnosing and managing patients with Chagas disease. Only 2 drugs exist with proven efficacy: benznidazole and nifurtimox. Benznidazole has historically faced supply problems and drug shortages, limiting accessibility. In the US, it is currently only available under an investigational new drug (IND) protocol from the CDC and is provided free of charge to patients. However, 2 companies have stated that they intend to submit a New Drug Application (NDA) for FDA approval. Based on recent history of companies acquiring licensing rights for NTD drugs in the US with limited availability, it is likely that benznidazole will become excessively priced by the manufacturer-paradoxically making it less accessible. However, if the companies can be taken at their word, there may be reason for optimism.

Topics: Centers for Disease Control and Prevention, U.S.; Chagas Disease; Drug Costs; Drugs, Investigational; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; United States; United States Food and Drug Administration

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.

Topics: Antiprotozoal Agents; Chagas Disease; Cysteine Endopeptidases; High-Throughput Screening Assays; Host-Parasite Interactions; Humans; Kinetoplastida; Molecular Docking Simulation; Molecular Structure; Nifurtimox; Nitroimidazoles; Protein Domains; Protozoan Proteins; Trypanosoma cruzi

Two old drugs are the only choice against Trypanosoma cruzi and little is known about their secondary effects in the acute stage of oral-transmitted Chagas disease (ChD).. A cross-sectional analytical surveillance study was conducted in a sizable cohort of patients seen during the largest acute foodborne ChD microepidemic registered so far. Individuals were treated with benznidazole (BNZ) or nifurtimox (NFX). 'Common Terminology Criteria for Adverse Events' was assessed to categorize side effects according to severity.. Out of 176 treatments applied, 79% had one or more adverse effects, which predominated in adults (97.8%) as compared to children (75.5%). Risk of side effects with NFX was significantly higher than BNZ. Four adults and a child treated with NFX had severe side effects (pulmonary infarction, facial paralysis, neutropenia, blurred vision, bone marrow hypoplasia) warranting hospitalization, and drug suspension. Adverse effects frequently reported with NFX were abdominal pain, hyporexia, weight loss, headache, nausea and lymphocytosis, whereas skin rash, neurosensory effects, hyporexia, fatigue, pyrosis, abdominal pain and eosinophilia were observed with BNZ.. Frequency and severity of side effects during treatment of acute oral infection by T. cruzi demand direct supervision and close follow-up, even in those asymptomatic, to prevent life-threatening situations.

Topics: Chagas Disease; Cross-Sectional Studies; Female; Humans; Male; Nifurtimox; Nitroimidazoles; Pharmacovigilance; Trypanocidal Agents; Trypanosoma cruzi

Antimicrobial resistance is an ever-increasing problem throughout the world and has already reached severe proportions. Two very common neglected tropical diseases are Chagas' disease and leishmaniasis. Chagas' disease is a severe health problem, mainly in Latin America, causing approximately 50000 deaths a year and millions of people are infected. About 25-30% of the patients infected with Trypanosoma cruzi develop the chronic form of the disease. On the other hand, Leishmaniasis represents complex diseases with an important clinical and epidemiological diversity. It is endemic in 88 countries 72 of which are developing countries and it has been estimated that are 12 million people infected and 350 million are in areas with infection risk. On this basis, research on organic compounds that can be used against these two diseases is an important target. A very simple, green, and efficient protocol is developed in which bismuth nitrate pentahydrate is employed as a Lewis acid catalyst in aqueous media under microwave irradiation for the synthesis of various 2-aryl substituted benzimidazoles from aldehydes and o-phenylenediamine. Other salient features of this protocol include milder conditions, atom-economy, easy extraction, and no wastes. Nine 1H-benzimidazole derivatives (1-9) with substituents at positions 2 and 5 were synthesized and the structure of the compounds was elucidated by spectroscopic methods. The compounds were screened to identify whether they posses pharmacological activity against Chagas' disease and leishmaniasis. Compound 8 showed better activity than the control Nifurtimox against INC-5 Trypanosoma cruzi strain whereas compounds 3 and 9 have demonstrated potent leshmanicidal activity. A systematic green synthetic procedure and in vitro biological evaluation of nine 1H-benzimidazoles are described.

Topics: Amphotericin B; Antiprotozoal Agents; Benzimidazoles; Chagas Disease; Green Chemistry Technology; Heating; Leishmania mexicana; Leishmaniasis; Microwaves; Nifurtimox; Nitroimidazoles; Trypanosoma cruzi

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 β-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.. 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.. 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.

Topics: Animals; Chagas Disease; Electrophoresis, Gel, Two-Dimensional; Mice; Naphthoquinones; Nifurtimox; Nitroimidazoles; Proteomics; Protozoan Proteins; Trypanocidal Agents; Trypanosoma cruzi

The insect-transmitted protozoan parasite Trypanosoma cruzi is the causative agent of Chagas disease, and infects 5-8 million people in Latin America. Chagas disease is characterised by an acute phase, which is partially resolved by the immune system, but then develops as a chronic life-long infection. There is a consensus that the front-line drugs benznidazole and nifurtimox are more effective against the acute stage in both clinical and experimental settings. However, confirmative studies have been restricted by difficulties in demonstrating sterile parasitological cure. Here, we describe a systematic study of nitroheterocyclic drug efficacy using highly sensitive bioluminescence imaging of murine infections. Unexpectedly, we find both drugs are more effective at curing chronic infections, judged by treatment duration and therapeutic dose. This was not associated with factors that differentially influence plasma drug concentrations in the two disease stages. We also observed that fexinidazole and fexinidazole sulfone are more effective than benznidazole and nifurtimox as curative treatments, particularly for acute stage infections, most likely as a result of the higher and more prolonged exposure of the sulfone derivative. If these findings are translatable to human patients, they will have important implications for treatment strategies.

Topics: Animals; Area Under Curve; Chagas Disease; Disease Models, Animal; Female; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C3H; Nifurtimox; Nitroimidazoles; Treatment Outcome; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, represents a very important public health problem in Latin America where it is endemic. Although mostly asymptomatic at its initial stage, after the disease becomes chronic, about a third of the infected patients progress to a potentially fatal outcome due to severe damage of heart and gut tissues. There is an urgent need for new drugs against Chagas disease since there are only two drugs available, benznidazole and nifurtimox, and both show toxic side effects and variable efficacy against the chronic stage of the disease.. Genetically engineered parasitic strains are used for high throughput screening (HTS) of large chemical collections in the search for new anti-parasitic compounds. These assays, although successful, are limited to reporter transgenic parasites and do not cover the wide T. cruzi genetic background. With the aim to contribute to the early drug discovery process against Chagas disease we have developed an automated image-based 384-well plate HTS assay for T. cruzi amastigote replication in a rat myoblast host cell line. An image analysis script was designed to inform on three outputs: total number of host cells, ratio of T. cruzi amastigotes per cell and percentage of infected cells, which respectively provides one host cell toxicity and two T. cruzi toxicity readouts. The assay was statistically robust (Z´ values >0.6) and was validated against a series of known anti-trypanosomatid drugs.. We have established a highly reproducible, high content HTS assay for screening of chemical compounds against T. cruzi infection of myoblasts that is amenable for use with any T. cruzi strain capable of in vitro infection. Our visual assay informs on both anti-parasitic and host cell toxicity readouts in a single experiment, allowing the direct identification of compounds selectively targeted to the parasite.

Topics: Animals; Automation, Laboratory; Cell Line; Chlorocebus aethiops; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Humans; Myoblasts; Nifurtimox; Nitroimidazoles; Rats; Trypanosoma cruzi

Chagas disease constitutes a major public health problem in Latin America. Human breast milk is a biological sample of great importance for the analysis of therapeutic drugs, as unwanted exposure through breast milk could result in pharmacological effects in the nursing infant. Thus, the goal of breast milk drug analysis is to inquire to which extent a neonate may be exposed to a drug during lactation. In this work, we developed an analytical technique to quantify benznidazole and nifurtimox (the two antichagasic drugs currently available for medical treatment) in human breast milk, with a simple sample pretreatment followed by an ionic-liquid-based dispersive liquid-liquid microextraction combined with high-performance liquid chromatography and UV detection. For this technique, the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate has been used as the "extraction solvent." A central composite design was used to find the optimum values for the significant variables affecting the extraction process: volume of ionic liquid, volume of dispersant solvent, ionic strength, and pH. At the optimum working conditions, the average recoveries were 77.5 and 89.7%, the limits of detection were 0.06 and 0.09 μg/mL and the interday reproducibilities were 6.25 and 5.77% for benznidazole and nifurtimox, respectively. The proposed methodology can be considered sensitive, simple, robust, accurate, and green.

Topics: Chagas Disease; Chromatography, High Pressure Liquid; Humans; Imidazoles; Ionic Liquids; Liquid Phase Microextraction; Milk, Human; Molecular Structure; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Ultraviolet Rays

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.. 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.. 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.. 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.

Topics: Alcohol Oxidoreductases; Animals; Cell Line; Cell Survival; Chagas Disease; Disease Models, Animal; Esters; Isoenzymes; Male; Mice; Nifurtimox; Nitroimidazoles; Oxamic Acid; Prodrugs; Trypanocidal Agents; Trypanosoma cruzi

There are 300,000 estimated cases of Chagas disease in the United States but limited data on access to care. This study analyzed trends in access to care for Chagas disease in the United States and assessed the national and state barriers to access. Data on cases in blood donors and drug releases were obtained from the AABB (formerly American Association of Blood Banks) and U.S. Centers for Disease Control and Prevention (CDC), respectively. Semi-structured in-depth interviews were conducted with 30 key informants at the national level and in five states where treatment had been released. Interview responses were analyzed according to the health systems dimensions of regulation, financing, payment, organization, and persuasion. Data indicate that 1,908 cases were identified in the blood donation system from 2007 to 2013 and that CDC released 422 courses of benznidazole or nifurtimox during this period. The barriers to access at the national level include limited diagnostic and institutionalized referral and care processes, lack of financing for patient-care activities, and limited awareness and training among providers. This study demonstrates that access to treatment of Chagas disease in the United States is limited. The lack of licensing is only one of several barriers to access, highlighting the need for a health systems perspective when scaling up access to these essential medicines.

Topics: Blood Donors; Centers for Disease Control and Prevention, U.S.; Chagas Disease; Clinical Competence; Delivery of Health Care; Drugs, Investigational; Health Services Accessibility; Humans; Nifurtimox; Nitroimidazoles; Referral and Consultation; Systems Analysis; Trypanocidal Agents; United States

Chagas disease is a major unsolved health issue in Latin America and an emerging threat worldwide. New drugs are urgently needed for chemotherapy as those available (benznidazole and nifurtimox) have variable efficacy and elevated toxicity. Efforts are actually oriented to improve tools and technologies (e.g. transgenic parasites, flow cytometry or image-based systems) for the screening of large numbers of candidate compounds for their activity against Trypanosoma cruzi (T. cruzi). Methods that test drug efficacy and selectivity in the same assay are suitable to accelerate the process of drug discovery. Here, we developed a GFP expressing T. cruzi from a moderate virulence stock and confirmed that the transgenic parasite retained the biological characteristics of the parental strain. With this tool, we established a flow cytometer-based method to simultaneously test drug activity against intracellular amastigotes and toxicity to the host cell. This one-step procedure allows determining the selectivity index of the tested compound in a sensitive and accurate manner even with low infection rates. This method can provide additional information on the interactions between drug, parasites and host cell and could be adapted to other trypanosomatids and protozoa with intracellular multiplication.

Topics: Chagas Disease; Drug Discovery; Flow Cytometry; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Trypanosoma cruzi, causative agent of Chagas disease, displays high intraspecific genetic diversity: six genetic lineages or discrete typing units (DTUs) are currently recognized, termed TcI through TcVI. Each DTU presents a particular distribution pattern across the Americas, and is loosely associated with different transmission cycles and hosts. Several DTUs are known to circulate in Central America. It has been previously suggested that TcI infection is benign and does not lead to chronic chagasic cardiomyopathy (CCC).. In this study, we genotyped T. cruzi parasites circulating in the blood and from explanted cardiac tissue of an El Salvadorian patient who developed reactivation Chagas disease while on immunosuppressive medications after undergoing heart transplant in the U.S. as treatment for end-stage CCC. Parasite typing was performed through molecular methods (restriction fragment length polymorphism of polymerase reaction chain amplified products, microsatellite typing, maxicircle sequence typing and low-stringency single primer PCR, [LSSP-PCR]) as well as lineage-specific serology. We show that the parasites infecting the patient belong to the TcI DTU exclusively. Our data indicate that the parasites isolated from the patient belong to a genotype frequently associated with human infection throughout the Americas (TcIDOM).. Our results constitute compelling evidence in support of TcI DTU's ability to cause end-stage CCC and help dispel any residual bias that infection with this lineage is benign, pointing to the need for increased surveillance for dissemination of this genotype in endemic regions, the USA and globally.

Topics: Adult; Chagas Cardiomyopathy; DNA, Protozoan; Heart Transplantation; Humans; Male; Nifurtimox; Nitroimidazoles; Phylogeny; Recurrence; Trypanocidal Agents; Trypanosoma cruzi

Topics: Animals; Arrhythmias, Cardiac; Chagas Cardiomyopathy; Chagas Disease; Death, Sudden, Cardiac; Defibrillators, Implantable; Disease Management; Heart Failure; Humans; Insect Control; Insect Vectors; Nifurtimox; Nitroimidazoles; Thromboembolism; Treatment Outcome; Trypanocidal Agents; Trypanosoma cruzi

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.. 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.. 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.. 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.

Topics: Acute Disease; Animals; Base Sequence; Chagas Disease; Colombia; Disease Outbreaks; DNA, Protozoan; Exons; Female; Genetic Variation; Genotype; Humans; Male; Molecular Sequence Data; Nifurtimox; Nitroimidazoles; Sequence Analysis, DNA; Trypanocidal Agents; Trypanosoma cruzi

Treatment for Chagas disease with currently available medications is recommended universally only for acute cases (all ages) and for children up to 14 years old. The World Health Organization, however, also recommends specific antiparasite treatment for all chronic-phase Trypanosoma cruzi-infected individuals, even though in current medical practice this remains controversial, and most physicians only prescribe palliative treatment for adult Chagas patients with dilated cardiomyopathy. The present opinion, prepared by members of the NHEPACHA network (Nuevas Herramientas para el Diagnóstico y la Evaluación del Paciente con Enfermedad de Chagas/New Tools for the Diagnosis and Evaluation of Chagas Disease Patients), reviews the paradigm shift based on clinical and immunological evidence and argues in favor of antiparasitic treatment for all chronic patients. We review the tools needed to monitor therapeutic efficacy and the potential criteria for evaluation of treatment efficacy beyond parasitological cure. Etiological treatment should now be mandatory for all adult chronic Chagas disease patients.

Topics: Adolescent; Adult; Antibodies, Protozoan; Chagas Cardiomyopathy; Child; Chronic Disease; Disease Management; Drug Administration Schedule; Humans; Nifurtimox; Nitroimidazoles; Practice Guidelines as Topic; Randomized Controlled Trials as Topic; Severity of Illness Index; Treatment Outcome; Trypanocidal Agents; Trypanosoma cruzi

The current Chagas disease treatment is based on two drugs, nifurtimox and benznidazole, which is considered unsatisfactory, not only because of the narrow therapeutic range but also because of the associated toxicity. Natural products are considered an important source of biologically active compounds against various infectious organisms. Numerous Piper species are used in traditional medicine to treat parasitic diseases. In this paper, we study the activity of extracts and fractions obtained from Piper jericoense plant against epimastigote, trypomastigote and amastigote forms of Trypanosoma cruzi. In addition, we evaluated the cytotoxic, mutagenic and genotoxic activities of the F4 fraction obtained from one of the more promising extracts. We obtained four extracts, one of which presented low toxicity and high trypanocidal activity. This extract was separated into eight fractions, and the F4 fraction presented better results than the other extracts and had a higher selectivity index than the reference drug, benznidazole. This fraction was not cytotoxic, mutagenic or genotoxic.

Topics: Cell Survival; Cells, Cultured; Chemical Fractionation; Culture Media; Humans; Life Cycle Stages; Lymphocytes; Mutagenicity Tests; Nifurtimox; Nitroimidazoles; Parasitic Sensitivity Tests; Piper; Plant Extracts; Trypanocidal Agents; Trypanosoma cruzi

Benznidazole is the main drug used to treat Trypanosoma cruzi infections. However, frequent instances of treatment failure have been reported. To better understand potential resistance mechanisms, we analysed three clones isolated from a single parasite population that had undergone benznidazole-selection. These clones exhibited differing levels of benznidazole-resistance (varying between 9 and 26-fold), and displayed cross-resistance to nifurtimox (2 to 4-fold). Each clone had acquired a stop-codon-generating mutation in the gene which encodes the nitroreductase (TcNTR) that is responsible for activating nitroheterocyclic pro-drugs. In addition, one clone had lost a copy of the chromosome containing TcNTR. However, these processes alone are insufficient to account for the extent and diversity of benznidazole-resistance. It is implicit from our results that additional mechanisms must also operate and that T. cruzi has an intrinsic ability to develop drug-resistance by independent sequential steps, even within a single population. This has important implications for drug development strategies.

Topics: Antiprotozoal Agents; Codon, Nonsense; Drug Resistance; Gene Deletion; Nifurtimox; Nitroimidazoles; Nitroreductases; Parasitic Sensitivity Tests; Trypanosoma cruzi

Nifurtimox (Nfx) and Benznidazole (Bnz) are the only available drugs in use for the treatment of Chagas disease. These drugs are recommended but not fully validated in evidence-based medicine and reports about the differential toxicity of both drugs are controversial. Here, we evaluated the toxic and therapeutic effects of Nfx and Bnz on human placental chorionic villi explants (HPCVE) during ex vivo infection of Trypanosoma cruzi, performing histopathological, histochemical, immunohistochemical as well as immunofluorescence analysis of the tissue. Additionally, we determined the effect of both drugs on parasite load by real time PCR. Bnz prevents the parasite induced tissue damage in ex vivo infected HPCVE compared to Nfx, which is toxic per se. The presence of T. cruzi antigens and DNA in infected explants suggests that these drugs do not impair parasite invasion into the HPCVE. Additionally, our results confirm reports suggesting that Bnz is less toxic than Nfx and support the need for the development of more effective and better-tolerated drugs.

Topics: Antiparasitic Agents; Chorionic Villi; Female; Histocytochemistry; Humans; Immunohistochemistry; In Vitro Techniques; Microscopy, Fluorescence; Nifurtimox; Nitroimidazoles; Parasite Load; Placenta; Pregnancy; Real-Time Polymerase Chain Reaction; Trypanosoma cruzi

Chagas disease or American Trypanosomiasis is caused by the flagellated protozoan parasite Trypanosoma cruzi (T. cruzi) and is recognized by the WHO as one of the world's 17 neglected tropical diseases. Only two drugs (Benznidazol, Bz and Nifurtimox, Nx) are currently accepted for treatment, however they cause severe adverse effects and their efficacy is still controversial. It is then important to explore for new drugs.. Programmed cell death (PCD) in parasites offers interesting new therapeutic targets. The aim of this work was to evaluate the induction of PCD in T. cruzi by two natural sesquiterpene lactones (STLs), dehydroleucodine (DhL) and helenalin (Hln) as compared with the two conventional drugs, Bz and Nx.. Hln and DhL were isolated from aerial parts of Gaillardia megapotamica and Artemisia douglassiana Besser, respectively. Purity of compounds (greater than 95%) was confirmed by (13)C-nuclear magnetic resonance, melting point analysis, and optical rotation. Induction of PCD in T. cruzi epimastigotes and trypomastigotes by DhL, Hln, Bz and Nx was assayed by phosphatidylserine exposure at the parasite surface and by detection of DNA fragmentation using the TUNEL assay. Trypanocidal activity of natural and synthetic compounds was assayed by measuring parasite viability using the MTT method.. The two natural STLs, DhL and Hln, induce programmed cell death in both, the replicative epimastigote form and the infective trypomastigote form of T. cruzi. Interestingly, the two conventional antichagasic drugs (Bz and Nx) do not induce programmed cell death. A combination of DhL and either Bz or Nx showed an increased effect of natural compounds and synthetic drugs on the decrease of parasite viability.. DhL and Hln induce programmed cell death in T. cruzi replicative epimastigote and infective trypomastigote forms, which is a different mechanism of action than the conventional drugs to kill the parasite. Therefore DhL and Hln may offer an interesting option for the treatment of Chagas disease, alone or in combination with conventional drugs.

Topics: Animals; Apoptosis; Artemisia; Chlorocebus aethiops; Lactones; Molecular Structure; Nifurtimox; Nitroimidazoles; Sesquiterpenes; Sesquiterpenes, Guaiane; Trypanocidal Agents; Trypanosoma cruzi; Vero Cells

Treatment of Chagas disease, caused by Trypanosoma cruzi, relies on nifurtimox and benznidazole (BZL), which present side effects in adult patients, and natural resistance in some parasite strains. Hydroxymethylnitrofurazone (NFOH) is a new drug candidate with demonstrated trypanocidal activity; however, its safety is not known.. HepG2 cells dose response to NFOH and BZL (5-100 µM) was assessed by measurement of ROS, DNA damage and survival. Swiss mice were treated with NFOH or BZL for short-term (ST, 21 d) or long-term (LT, 60 d) periods. Sera levels of cellular injury markers, liver inflammatory and oxidative stress, and fibrotic remodeling were monitored.. HepG2 cells exhibited mild stress, evidenced by increased ROS and DNA damage, in response to NFOH, while BZL at 100 µM concentration induced >33% cell death in 24 h. In mice, NFOH ST treatment resulted in mild-to-no increase in the liver injury biomarkers (GOT, GPT), and liver levels of inflammatory (myeloperoxidase, TNF-α), oxidative (lipid peroxides) and nitrosative (3-nitrotyrosine) stress. These stress responses in NFOH LT treated mice were normalized to control levels. BZL-treated mice exhibited a >5-fold increase in GOT, GPT and TNF-α (LT) and a 20-40% increase in liver levels of MPO activity (ST and LT) in comparison with NFOH-treated mice. The liver inflammatory infiltrate was noted in the order of BZL>vehicle≥NFOH and BZL>NFOH≥vehicle, respectively, after ST and LT treatments. Liver fibrotic remodeling, identified after ST treatment, was in the order of BZL>vehicle>NFOH; lipid deposits, indicative of mitochondrial dysfunction and in the order of NFOH>vehicle>BZL were evidenced after LT treatment.. NFOH induces mild ST hepatotoxicity that is normalized during LT treatment in mice. Our results suggest that additional studies to determine the efficacy and toxicity of NFOH are warranted.

Topics: Animals; Cell Death; Cell Line, Tumor; Chagas Disease; Chemical and Drug Induced Liver Injury; DNA Damage; Female; Hep G2 Cells; Humans; Liver; Male; Mice; Mitochondria; Nifurtimox; Nitrofurazone; Nitroimidazoles; Parasites; Reactive Oxygen Species; Trypanocidal Agents; Trypanosoma cruzi; Tumor Necrosis Factor-alpha; Tyrosine

The outbreak of acute Chagas disease due to oral transmission of the parasite is a well-known phenomenon mainly occurring in the Amazon. Such an event is described here for the first time in French Guiana. Eight patients of the same family, presenting epidemiological and clinical histories compatible with recent Trypanosoma cruzi infection of Chagas disease due to the ingestion of palm Oenocarpus bacaba juice were, rather late after the putative date of infection, underwent four parasitological and two serological specific tests for confirmation of the diagnosis. Real-time PCR results were positive for all the patients; strains were isolated by hemoculture from four patients, PCR identification of TcI DTU was made for six patients, while parasites were not detected in any of the patients by direct microscopic examination. The results of two serologic tests were positive. All patients were treated with benznidazole, and two patients were additionally given nifurtimox. A 6-year follow-up was possible for six patients. Real-time PCR was negative for these patients after 1 year, while the antibody rates decreased slowly and serology results were negative only after several years (1-5 years). Our findings confirm the occurrence of an outbreak of Chagas infection in members of the same family, with the oral mode of infection being the most likely hypothesis to explain this group of cases. Our results show the successful treatment of patients infected by TcI and the usefulness of real-time PCR for the emergency diagnosis of recent Chagas disease cases and in posttreatment follow-up.

Topics: Adolescent; Adult; Aged; Arecaceae; Chagas Disease; Child; Family; Female; French Guiana; Humans; Male; Middle Aged; Nifurtimox; Nitroimidazoles; Plant Extracts; Treatment Outcome; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease (CD) is endemic in Central and South America, Mexico and even in some areas of the United States. However, cases have been increasingly recorded also in non-endemic countries. The estimated number of infected people in Europe is in a wide range of 14000 to 181000 subjects, mostly resident in Spain, Italy and the United Kingdom.. Retrospective, observational study describing the characteristics of patients with CD who attended the Centre for Tropical Diseases (Negrar, Verona, Italy) between 2005 and 2013. All the patients affected by CD underwent chest X-ray, ECG, echocardiography, barium X-ray of the oesophagus and colonic enema. They were classified in the indeterminate, cardiac, digestive or mixed category according to the results of the screening tests. Treatment with benznidazole (or nifurtimox in case of intolerance to the first line therapy) was offered to all patients, excluding the ones with advanced cardiomiopathy, pregnant and lactating women. Patients included were 332 (73.9% women). We classified 68.1% of patients as having Indeterminate Chagas, 11.1% Cardiac Chagas, 18.7% as Digestive Chagas and 2.1% as Mixed Form. Three hundred and twenty-one patients (96.7%) were treated with benznidazole, and most of them (83.2%) completed the treatment. At least one adverse effect was reported by 27.7% of patients, but they were mostly mild. Only a couple of patients received nifurtimox as second line treatment.. Our case series represents the largest cohort of T. cruzi infected patients diagnosed and treated in Italy. An improvement of the access to diagnosis and cure is still needed, considering that about 9200 infected people are estimated to live in Italy. In general, there is an urgent need of common guidelines to better classify and manage patients with CD in non-endemic countries.

Topics: Adolescent; Adult; Aged; Chagas Disease; Child; Echocardiography; Electrocardiography; Female; Humans; Italy; Male; Middle Aged; Nifurtimox; Nitroimidazoles; Pregnancy; Retrospective Studies; Tropical Medicine; United States

Here we report identification of new lead compounds based on quinoline and indenoquinolines with variable side chains as antiprotozoal agents. Quinolines 32, 36 and 37 (Table 1) and indenoquinoline derivatives 14 and 23 (Table 2) inhibit the in vitro growth of the Trypanosoma cruzi, Trypanosoma brucei, Trypanosoma brucei rhodesiense subspecies and Leishmania infantum with IC50=0.25 μM. These five compounds have superior activity to that of the front-line drugs such as benznidazole, nifurtimox and comparable to amphotericin B. Thus these compounds constitute new 'leads' for further structure-activity studies as potential active antiprotozoal agents.

Topics: Amphotericin B; Antiprotozoal Agents; Cell Line; Cell Survival; Humans; Leishmania infantum; Nifurtimox; Nitroimidazoles; Parasitic Sensitivity Tests; Quinolines; Structure-Activity Relationship; Trypanosoma brucei brucei; Trypanosoma brucei rhodesiense; Trypanosoma cruzi

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi, and it affects as many as 10 million people in North and South America, where it represents a major public health problem. T. cruzi is a parasite with high genetic diversity, and it has been grouped into 6 discrete typing units (DTUs), designated as T. cruzi I (TcI) to T. cruzi VI (TcVI). Mexican isolates from humans and from vector insects have been primarily found to be TcI, and these isolates are likely to be the strains that cause the clinical manifestations observed in Mexico. However, genetic characterization and drug susceptibility assays are limited in Mexican TcI strains. In this work, 24 Mexican T. cruzi strains, obtained primarily from humans, were studied with 7 locus microsatellites and mini-exon gene by PCR. Also, drug susceptibility was evaluated by growth and mobility assays. All of the human strains belonged to TcI, and they could be further grouped through microsatellite analysis into 2 subgroups (microsatellite genotypes 1 and 2), which were not related to the host clinical status or biological origin of the strain. Two strains, both from wild mammals, belonged to the TcII-TcVI groups; these strains and the CL Brener strain constituted microsatellite genotype 3. The number of alleles in each locus was lower than reported for South American strains, and a departure from the Hardy-Weinberg equilibrium was observed. The susceptibility of these strains to nifurtimox and benznidazole was heterogeneous. T. cruzi strains characterized as microsatellite genotypes 2 and 3 were significantly more susceptible to benznidazole than strains of microsatellite genotype 1. Only 1 Mexican strain resistant to both drugs was found in this study.

Topics: Animals; Chagas Disease; DNA, Protozoan; Drug Resistance; Exons; Genetic Variation; Genotype; Humans; Insect Vectors; Mexico; Microsatellite Repeats; Nifurtimox; Nitroimidazoles; Opossums; Phylogeny; Polymerase Chain Reaction; Triatoma; Trypanocidal Agents; Trypanosoma cruzi

Currently, only two drugs are approved for treating Trypanosoma cruzi infection: benznidazole and nifurtimox. Adverse reactions are frequent with both drugs: they have chemical similarities and common metabolic pathways making cross reactions a possibility. Our objective was to describe the safety/tolerability profile of nifurtimox in patients who had previously discontinued benznidazole due to hypersensitivity reactions. We performed a prospective observational study from September 2009 to December 2011. Patients who discontinued benznidazole therapy due to hypersensitivity reactions (HR) and were later treated with nifurtimox were included. HR to benznidazole were defined as presence of a rash with or without mucosal involvement, fever or laboratory abnormalities (such as eosinophilia, leucopaenia or impaired liver function tests). The drugs were prescribed for 60 days (benznidazole) or 60-90 days (nifurtimox). The National Cancer Institute criteria (CTCAE, 2006, Version 3.0) were used for grading and reporting of adverse reactions (AR). Eighteen patients (16 females, two males, median age 35.5 years, range 15-50 years) with asymptomatic late chronic infection, were included. Median time between benznidazole interruption and start of therapy with nifurtimox was 121.5 days (IQR 72-223 days). Fifteen patients (83.3%) developed an AR to nifurtimox, gastrointestinal complaints and anorexia being the most common, and 13 patients (72%) completed the treatment schedule. Five patients interrupted therapy (27.8%) mainly because of gastrointestinal intolerance and/or nervous system toxicity. Only one patient developed skin lesions, a mild maculopapular rash not requiring specific therapy or treatment withdrawal. There was no severe AR. Nifurtimox as second line therapy in patients who discontinued benznidazole specifically due to HR appears to be safe and does not seem to be associated with a higher incidence of AR.

Topics: Adolescent; Adult; Chagas Disease; Drug Hypersensitivity; Female; Humans; Male; Middle Aged; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Young Adult

Dispersive ionic liquid-liquid microextraction combined with liquid chromatography and UV detection was used for the determination of two antichagasic drugs in human plasma: nifurtimox and benznidazole. The effects of experimental parameters on extraction efficiency-the type and volume of ionic liquid and disperser solvent, pH, nature and concentration of salt, and the time for centrifugation and extraction-were investigated and optimized. Matrix effects were detected and thus the standard addition method was used for quantification. This microextraction procedure yielded significant improvements over those previously reported in the literature and has several advantages, including high inter-day reproducibility (relative standard deviation=1.02% and 3.66% for nifurtimox and benznidazole, respectively), extremely low detection limits (15.7 ng mL(-1) and 26.5 ng mL(-1) for nifurtimox and benznidazole, respectively), and minimal amounts of sample and extraction solvent required. Recoveries were high (98.0% and 79.8% for nifurtimox and benznidazole, respectively). The proposed methodology offers the advantage of highly satisfactory performance in addition to being inexpensive, simple, and fast in the extraction and preconcentration of these antichagasic drugs from human-plasma samples, with these characteristics being consistent with the practicability requirements in current clinical research or within the context of therapeutic monitoring.

Topics: Chromatography, High Pressure Liquid; Humans; Ionic Liquids; Limit of Detection; Liquid Phase Microextraction; Nifurtimox; Nitroimidazoles; Reproducibility of Results; Trypanocidal Agents

Nifurtimox (Nfx) and benznidazole (Bz) have serious toxic side effects. Manufacturers warn about significant adverse effects when simultaneous alcohol consumption is being made, but its mechanism is not known. The levels and toxicity of these drugs are linked to their liver microsomal nitroreduction to reactive metabolites. In this study, we analyzed whether alcohol drinking enhanced those nitroreductive processes. Male and female Sprague-Dawley rats, 5-6 weeks old (125-150 g body weight) were used. They were fed ad libitum for 28 days with Lieber and De Carli control or alcohol regular liquid diets. The rats were separated into two dietary groups: ethanol and control group. Both were pair fed with the respective diet. Their liver microsomes were isolated and the nicotinamide adenine dinucleotide phosphate-dependent nitroreduction of Nfx and Bz were determined. Alcohol drinking significantly induced microsomal nitroreduction of these drugs in male rats (11% for Nfx and 41% for Bz) but not in females. The activity observed in the alcohol-induced male rats was 100% inhibited by diphenyleneiodonium and attributable to P450 reductase. Inductive effects of alcohol drinking on nitroreductive activation of both drugs might be only partially involved in the harmful interactions described.

Topics: Alcohol Drinking; Animals; Drug Interactions; Female; Male; Microsomes, Liver; Nifurtimox; Nitroimidazoles; Nitroreductases; Rats; Rats, Sprague-Dawley; Trypanocidal Agents

This work compared the time at which negative seroconversion was detected by conventional serology (CS) and by the ELISA-F29 test on a cohort of chronic chagasic patients treated with nifurtimox or benznidazole. A retrospective study was performed using preserved serum from 66 asymptomatic chagasic adults under clinical supervision, and bi-annual serological examinations over a mean follow-up of 23 years. Twenty nine patients received trypanocide treatment and 37 remained untreated. The ELISA-F29 test used a recombinant antigen which was obtained by expressing the Trypanosoma cruzi flagellar calcium-binding protein gene in Escherichia coli. Among the untreated patients, 36 maintained CS titers. One patient showed a doubtful serology in some check-ups. ELISA-F29 showed constant reactivity in 35 out of 37 patients and was negative for the patient with fluctuating CS. The treated patients were divided into three groups according to the CS titers: in 13 they became negative; in 12 they decreased and in four they remained unchanged. ELISA-F29 was negative for the first two groups. The time at which negativization was detected was significantly lower for the ELISA-F29 test than for CS, 14.5 ± 5.7 and 22 ± 4.9 years respectively. Negative seroconversion was observed in treated patients only. The results obtained confirm that the ELISA-F29 test is useful as an early indicator of negative seroconversion in treated chronic patients.

Topics: Adolescent; Adult; Antibodies, Protozoan; Antigens, Protozoan; Case-Control Studies; Chagas Disease; Chronic Disease; Cohort Studies; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Nifurtimox; Nitroimidazoles; Retrospective Studies; Time Factors; Treatment Outcome; Trypanocidal Agents; Trypanosoma cruzi; Young Adult

Current therapies against African and American trypanosomiasis are problematic and with no immediate prospect of a vaccine there is an urgent need for cheap, more effective treatments. To aid the drug discovery pipeline, we report a novel in vivo screening approach using zebrafish (Danio rerio) embryos as a means of rapidly assessing a compounds developmental toxicity. This technique, amenable to high-throughput screening, was validated using several trypanocidal nitroaromatic prodrugs including nifurtimox and benznidazole.

Topics: Animals; Drug Evaluation, Preclinical; Embryo, Nonmammalian; High-Throughput Screening Assays; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Zebrafish

Topics: Chagas Disease; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

Topics: Chagas Disease; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Chagas' disease is a zoonosis caused by a protozoan agent, Trypanosoma cruzi. Patients undergoing immunosuppressive treatment due to organ transplant, malignancies, infections, or chemotherapy may reactivate a preexisting chronic or indeterminate Trypanosoma cruzi infection.. We present two transplant patients who underwent reactivation of Chagas' disease with cutaneous manifestations after an augmentation in their immunosuppressive therapy. A 38-year-old man was hospitalized on day 69 after receiving an allogeneic bone marrow transplant; he developed multiple painful erythematous plaques with diffuse borders, confined to the right cheek, trunk, thigh, elbows, and feet. A 59-year-old woman with a 14-year history of Chagasic cardiomyopathy presented one month after heart transplantation with a painful infiltrated purpuric plaque on the back of her right leg.. In both cases, histologic examination of skin biopsies showed dermal infiltration with intrahistiocytic amastigotes. In one of the reported cases, the Strout method detected parasitemia. Treatments with nifurtimox (600 mg/d) in case 1 and benznidazole (400 mg/d) in case 2 were started. Fever and cutaneous lesions resolved immediately after seven days of treatment.. Reactivation of Chagas' disease is a serious complication that usually occurs in immunocompromised patients. Clinical manifestations include febrile illness occasionally associated with painful skin lesions. Early diagnosis and proper treatment can significantly improve these patients' outcome.

Topics: Adult; Bone Marrow Transplantation; Chagas Disease; Female; Heart Transplantation; Humans; Immunocompromised Host; Immunosuppressive Agents; Male; Middle Aged; Nifurtimox; Nitroimidazoles; Recurrence; Trypanocidal Agents

Nitroheterocyclic prodrugs are used to treat infections caused by Trypanosoma cruzi and Trypanosoma brucei. A key component in selectivity involves a specific activation step mediated by a protein homologous with type I nitroreductases, enzymes found predominantly in prokaryotes. Using data from determinations based on flavin cofactor, oxygen-insensitive activity, substrate range, and inhibition profiles, we demonstrate that NTRs from T. cruzi and T. brucei display many characteristics of their bacterial counterparts. Intriguingly, both enzymes preferentially use NADH and quinones as the electron donor and acceptor, respectively, suggesting that they may function as NADH:ubiquinone oxidoreductases in the parasite mitochondrion. We exploited this preference to determine the trypanocidal activity of a library of aziridinyl benzoquinones against bloodstream-form T. brucei. Biochemical screens using recombinant NTR demonstrated that several quinones were effective substrates for the parasite enzyme, having K(cat)/K(m) values 2 orders of magnitude greater than those of nifurtimox and benznidazole. In tests against T. brucei, antiparasitic activity mirrored the biochemical data, with the most potent compounds generally being preferred enzyme substrates. Trypanocidal activity was shown to be NTR dependent, as parasites with elevated levels of this enzyme were hypersensitive to the aziridinyl agent. By unraveling the biochemical characteristics exhibited by the trypanosomal NTRs, we have shown that quinone-based compounds represent a class of trypanocidal compound.

Topics: Benzoquinones; Escherichia coli; Kinetics; Mitochondria; Molecular Targeted Therapy; NAD; Nifurtimox; Nitroimidazoles; Nitroreductases; Prodrugs; Protozoan Proteins; Recombinant Proteins; Small Molecule Libraries; Structure-Activity Relationship; Substrate Specificity; Trypanocidal Agents; Trypanosoma brucei brucei; Trypanosoma cruzi

The present work aimed to investigate the curative effect of benznidazole (BZL) in combination with other patented drugs [nifurtimox (NFX), posaconazole (POS) or AmBisome(®) (AMB)] in mice acutely or chronically infected with either a BZL-susceptible (Tulahuen) or a BZL-partially-resistant (Y) strain of Trypanosoma cruzi. To appreciate the eventual advantage of such combinations, infected mice were treated for short durations (non-curative) of each individual treatment. Cure rates were determined by investigating blood parasites (microscopic examination) and parasite DNA (quantitative PCR) after submitting treated mice to immune suppression with cyclophosphamide. The results mainly suggest that shorter durations of treatment combining BZL and POS or NFX might cure mice acutely or chronically infected with the Tulahuen strain, whereas the combination of BZL with AMB does not have such an effect. Moreover, the association BZL+POS does not improve the curative effect of POS (all used for shorter durations) in infection with the Y strain. Shortening the duration of treatment whilst keeping a complete curative effect deserves interest in limiting adverse reactions due to dose-cumulative toxic effects of long treatment. Genotyping of the T. cruzi strain(s) infecting patients might also allow a better adaptation of individual therapeutic schedules, improving both the efficiency and safety of trypanocidal treatment. This preliminary experimental study should encourage further investigations to find the best combination of adequate drug concentrations and timing of treatment.

Topics: Amphotericin B; Animals; Chagas Disease; Disease Models, Animal; DNA, Protozoan; Drug Therapy, Combination; Female; Mice; Mice, Inbred BALB C; Nifurtimox; Nitroimidazoles; Parasite Load; Parasitemia; Real-Time Polymerase Chain Reaction; Treatment Outcome; Triazoles; Trypanocidal Agents; Trypanosoma cruzi

To be effective, therapeutic compounds must typically enter target cells and, in some cases, must be concentrated or modified. Thus, uptake and activation mechanisms often form the basis of selectivity against infectious agents. Loss-of-function screens can be used to identify proteins involved in drug uptake and metabolism and may also identify clinically relevant potential resistance mechanisms. We used a genome-scale RNA interference (RNAi) library to identify loss-of-function resistance mechanisms in bloodstream-form Trypanosoma brucei. Nifurtimox-Eflornithine Combination Therapy (NECT) was recently introduced for Human African Trypanosomiasis and we focus on these drugs here. Screens for resistance to nifurtimox and a related drug, benznidazole, identified loss of nitroreductase (NTR) pro-drug activator function. A screen for resistance to the amino-acid analogue, eflornithine, identified loss of amino-acid transporter (AAT6) function. Our results confirm recent findings and suggest that NTR or AAT6 loss-of-function represent major potential mechanisms of resistance to these drugs. Thus, bloodstream-form T. brucei RNAi libraries present a versatile tool for selective genetic screening and for the rapid identification of drug-activation, uptake and potential resistance mechanisms.

Topics: Amino Acid Transport Systems; Drug Resistance; Eflornithine; Gene Knockdown Techniques; Genes, Protozoan; Genome-Wide Association Study; Humans; Nifurtimox; Nitroimidazoles; Nitroreductases; RNA Interference; Trypanosoma brucei brucei

We investigated the relationship between potentially pathogenic antibodies against a Trypanosoma cruzi ribosomal protein (P2β) and the evolution of Chagas disease and the effect of trypanocidal treatment on these variables. Seventy-eight patients with chronic Chagas disease who were followed-up for more than 20 years were divided into three groups: 30 asymptomatic persons undergoing specific treatment (group A), 37 asymptomatic persons not undergoing specific treatment (group B), and 11 patients with chronic chagasic cardiomyopathy (CCC) who were not treated. Five patients in group B showed evolution to myocardial abnormalities. Among persons with CCC, six showed no changes; the remaining persons showed progression of cardiac involvement. Levels of antibodies to P2β in persons in group A decreased from their initial values. This finding was not observed in persons in groups B and C. Comparisons at the end of the follow-up showed lower amounts of antibodies to P2β in groups A and C. These findings support the benefits of specific treatment during chronic infection.

Topics: Animals; Antibodies, Protozoan; Cardiomyopathies; Chagas Disease; Chronic Disease; Female; Humans; Immunity, Humoral; Male; Nifurtimox; Nitroimidazoles; Protozoan Proteins; Ribosomal Proteins; Trypanocidal Agents; Trypanosoma cruzi

Nifurtimox and benznidazole are the only active drugs against Trypanosoma cruzi; however, they have limited efficacy and severe side effects. During primoinfection, T. cruzi infected macrophages mount an antiparasitic response, which the parasite evades through an increase of tumor growth factor beta and PGE(2) activation as well as decreased iNOS activity. Thus, prostaglandin synthesis inhibition with aspirin might increase macrophage antiparasitic activity and increase nifurtimox and benznidazole effect. Aspirin alone demonstrated a low effect upon macrophage antiparasitic activity. However, isobolographic analysis of the combined effects of aspirin, nifurtimox and benznidazole indicated a synergistic effect on T. cruzi infection of RAW cells, with combinatory indexes of 0.71 and 0.61, respectively. The observed effect of aspirin upon T. cruzi infection was not related with the PGE(2) synthesis inhibition. Nevertheless, NO() levels were restored by aspirin in T. cruzi-infected RAW cells, contributing to macrophage antiparasitic activity improvement. Thus, the synergy of aspirin with nifurtimox and benznidazole is due to the capability of aspirin to increase antiparasitic activity of macrophages.

Topics: Animals; Aspirin; Cell Line; Cell Survival; Cyclooxygenase Inhibitors; Drug Synergism; Inhibitory Concentration 50; Macrophages; Mice; Nifurtimox; Nitric Oxide; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Two nitroheterocyclic drugs, nifurtimox (NFX) and benznidazole (BZ), used in the treatment of Chagas' disease have serious side effects attributed to their nitroreduction to reactive metabolites. Here, we report that these drugs reach the mammary tissue and there they could undergo in situ bioactivation. Both were detected in mammary tissue from female Sprague-Dawley rats after their intragastric administration. Only NFX was biotransformed by pure xanthine-oxidoreductase and from tissue cytosol. These activities were purine dependent and were inhibited by allopurinol. Also, only NFX was biotransformed by microsomes in the presence of β-nicotinamide adenine dinucleotide phosphate, reduced form (NADPH), and was inhibited by carbon monoxide and partially by diphenyleneiodonium. NFX treatment produced significant decrease in protein sulfhydryl content after 1, 3 and 6 hours; no increases in protein carbonyl content at any time tested and significantly higher levels of lipid hydroperoxides at 3 and 6 hours; besides, ultrastructural observations after 24 hours showed significant differences in epithelial cells compared to control. These findings indicate that NFX might be more deleterious to mammary tissue than BZ and could correlate with early reports on its ability to promote rat mammary tissue toxicity.

Topics: Allopurinol; Animals; Cell Fractionation; Chromatography, High Pressure Liquid; Female; Lipid Peroxidation; Mammary Glands, Animal; Microscopy, Electron, Transmission; Microsomes; Nifurtimox; Nitroimidazoles; Nitroreductases; Protein Carbonylation; Rats; Rats, Sprague-Dawley; Sulfhydryl Compounds; Trypanocidal Agents

Chagas' disease (CD) is caused by the protozoan Trypanosoma cruzi (Tc) and remains an important cause of morbidity and mortality. Most researchers in the field now agree that chronic low grade parasite persistence in tissue drives tissue damage and the autoimmune component of CD. Current therapy relies on two compounds: benznidazole and nifurtimox. Despite their long history in the treatment of CD, both compounds induce significant side-effects. In the current issue of the BJP, two contributions demonstrate that NO-donors are active, especially in combination with benznidazole, against Tc in vitro and in experimental models in vivo. The basic concept used by the authors to develop novel anti-Tc compounds relied on the demonstrated ability of nitric oxide to kill the parasite. There are several issues still to be resolved but the reported studies are a clear advance to the field and should be considered for further pre-clinical development.

Topics: Animals; Chagas Disease; Humans; Nifurtimox; Nitric Oxide Donors; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Topics: Chagas Cardiomyopathy; Chagas Disease; Clinical Trials as Topic; Drug Administration Schedule; Drug Eruptions; Humans; Meta-Analysis as Topic; Nifurtimox; Nitroimidazoles; Polyneuropathies; Trypanocidal Agents; Trypanosoma cruzi; United States

Little is known about the immune responses of newborns with congenital Chagas disease (CCD) or congenital toxoplasmosis (CT) but they probably differ to those seen in adults with Chagas disease or toxoplasmosis, leading to differences in pathology. The concentrations of interleukin-18 (IL-18), interferon-γ (IFN-γ) and interleukin 10 (IL-10) in the sera of infants with CCD or CT were determined and compared with those in the sera of uninfected controls (born to mothers who were seropositive or seronegative for Trypanosoma cruzi). The infants with CCD or CT were found to have lower IL-18 and IFN-γ concentrations but higher IL-10 concentrations than the uninfected controls. The IL-18 and IFN-γ concentrations were also significantly lower in the infants with CCD than in those with CT. Although the infants with symptomatic CT had significantly higher serum concentrations of IL-18 than those with asymptomatic infection with Toxoplasma, the infants with symptomatic CCD had similar serum concentrations of IL-18 to the infants with asymptomatic Tr. cruzi infection. Taken together, these results indicate that IL-10 contributes to the suppression of pro-inflammatory immune responses and therefore, perhaps, to clinically overt CCD and CT.

Topics: Chagas Disease; Enzyme-Linked Immunosorbent Assay; Female; Humans; Infant; Infant, Newborn; Interferon-gamma; Interleukin-10; Interleukin-18; Male; Nifurtimox; Nitroimidazoles; Toxoplasmosis, Congenital; Trypanocidal Agents

New 5-nitroindazole derivatives were developed and their antichagasic properties studied. Eight compounds (14-18, 20, 26 and 28) displayed remarkable in vitro activities against Trypanosoma cruzi (T. cruzi). Its unspecific cytotoxicity against macrophages was evaluated being not toxic at a concentration at least twice that of T. cruzi IC(50), for some derivatives. The electrochemical studies, parasite respiration studies and ESR experiment showed that 5-nitroindazole derivatives not be able to yield a redox cycling with molecular oxygen such as occurs with nifurtimox (Nfx). The study on the mechanism of action proves to be related to the production of reduced species of the nitro moiety similar to that observed with benznidazole.

Topics: Chagas Disease; Crystallography, X-Ray; DNA, Protozoan; HeLa Cells; Humans; Indazoles; Nitroimidazoles; Oxidation-Reduction; Parasitic Sensitivity Tests; Structure-Activity Relationship; Trypanocidal Agents; Trypanosoma cruzi

Chagas disease (human American trypanosomiasis) is a zoonose caused by the protozoan Trypanosoma cruzi. Vectors are Triatoma spp. insects. T. cruzi can also be transmitted by blood transfusion, organ transplantation, and transplacentally. Infection is generally acquired during infancy. The acute infection is rarely symptomatic and is followed by a chronic phase. Chronic infected people are asymptomatic (indeterminate stage) and may remain at this stage for the rest of their lives. About a third of infected people will develop a chronic Chagas disease which affects the heart and the digestive tract. Morbidity and mortality of chronic Chagas cardiomyopathy (CCC) are high. Specific treatment of asymptomatic infected individual could reduce the risk of progression to CCC. With control initiatives case incidence declined in most endemic countries. American trypanosomiasis has become an emerging imported disease in North America and Europe because of the migration of population originating from endemic zones. They are only two available drugs for specific treatment of Chagas disease: benznidazole and nifurtimox. Both have frequent side effects and variable efficacy according the phase of the disease. There is an urgent need for new treatments and better serological tests. Policies must be developed to avoid the risk of transmission trough blood transfusion and transplantation in developed countries.

Topics: Animals; Chagas Disease; Emigration and Immigration; Humans; Insect Vectors; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

Alcohol dehydrogenases (ADH) are a class of oxidoreductases that catalyse the reversible oxidation of ethanol to acetaldehyde. In the human parasite Trypanosoma cruzi the TcADH gene was identified through microarray analysis as having reduced transcription in an in vitro induced benznidazole (BZ)-resistant population. In the present study, we have extended these results by characterizing the TcADH gene from 11 strains of T. cruzi that were either susceptible or naturally resistant to benznidazole and nifurtimox or had in vivo selected or in vitro induced resistance to BZ. Sequence comparisons showed that TcADH was more similar to prokaryotic ADHs than to orthologs identified Leishmania spp. Immunolocalisation using confocal microscopy revealed that TcADH is present in the kinetoplast region and along the parasite body, consistent with the mitochondrial localization predicted by sequence analysis. Northern blots showed a 1.9kb transcript with similar signal intensity in all T. cruzi samples analysed, except for the in vitro selected resistant population, where transcript levels were 2-fold lower. These findings were confirmed by quantitative real-time PCR. In Western blot analysis, anti-TcADH polyclonal antisera recognised a 42kDa protein in all T. cruzi strains tested. The level of expression of this polypeptide was approximately 2-fold lower in the in vitro induced benznidazole-resistant strain, than in the susceptible parental strain. The chromosomal location of the TcADH gene was variable, but was not associated with the zymodeme or with the drug resistance phenotype. The data presented here show that the TcADH enzyme has a decreased level of expression in the in vitro induced BZ-resistant T. cruzi population, a situation that has not been observed in the in vivo selected BZ-resistant and naturally resistant strains.

Topics: Alcohol Dehydrogenase; Animals; Blotting, Northern; DNA, Protozoan; Drug Resistance; Humans; Immunoblotting; Mice; Molecular Weight; Nifurtimox; Nitroimidazoles; Phylogeny; Protozoan Proteins; RNA, Messenger; RNA, Protozoan; Sequence Analysis, DNA; Sequence Homology; Trypanocidal Agents; Trypanosoma cruzi

Topics: Americas; Central Nervous System Diseases; Chagas Disease; History, 20th Century; History, 21st Century; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

In the immunocompromised patients, the main features of Chagas disease are severe clinical manifestations during the acute phase and reactivations occurring during the chronic phase. Reactivation is defined by a demonstration of trypomastigots on microscopic examination of blood or the identification of amastigots on biopsy samples and/or acute clinical manifestations during the chronic phase. In HIV patients, meningo-encephalitis and myocarditis are the major clinical syndromes of reactivation. In transplanted patients, cutaneous lesions often reveal the reactivation. A parasiticidal treatment (nifurtimox or benznidazole) should be initiated immediately. A secondary prophylaxis is indicated for HIV patients with CD4 cells count < 200/mm3. In the near future, quantitative PCR could allow to diagnose early reactivation, to initiate preemptive therapy and to closely monitor the therapeutic response. Due to the severe manifestations and prognosis of Chagas disease in the immunocompromised host, two serologic tests must be performed in the patient with an history of residency in endemic countries.

Topics: Anti-HIV Agents; Chagas Disease; France; HIV Infections; Humans; Meningoencephalitis; Nifurtimox; Nitroimidazoles; Transplantation; Trypanocidal Agents

The current chemotherapy for Chagas disease is unsatisfactory with only two drugs available for treatment. Research to discover new drugs for Chagas disease is urgent. Hexadecyl-phosphocholine (HPC, miltefosine) has been demonstrated to have in vitro activity against Trypanosoma cruzi parasites, but its activity on different Colombian T. cruzi strains is not known.. To evaluate the in vitro susceptibility of T. cruzi strains isolated from humans and vectors in Santander, Colombia. to miltefosine, nifurtimox and benznidazole.. Eight T. cruzi Colombian strains and three reference strains (Esmeraldo, SilvioX10 and Y) were studied. Drug activities against extracellular epimastigotes and intracellular amastigotes were determined by microscopic counting. The results were expressed as the concentrations that inhibited 50% and 90% growth (IC50 and IC90).. For miltefosine a similar range of drug activity was observed against all the Colombian strains, all parasites being more susceptible to miltefosine than to the reference drugs. The intracellular amastigotes were more susceptible to miltefosine (IC50 0.08 to 0.63 microM and IC90 0.21 to 2.21 microM) than extracellular forms (IC50 <0.92 to 2.29 microM and IC90 1.38 to 4.76 microM). For reference drugs, parasites were more susceptible to nifurtimox than to benznidazole and some differences in activity of benznidazole between T. cruzi strains was observed.. The results showed the significant in vitro activity of miltefosine against T. cruzi stages, and the expected results for the reference drugs. Further in vivo studies with miltefosine are planned.

Topics: Antiprotozoal Agents; Colombia; Nifurtimox; Nitroimidazoles; Parasitic Sensitivity Tests; Phosphorylcholine; Trypanosoma cruzi

As expert consensus has been arisen about universal antiparasitic treatment for all patients infected with Trypanosoma cruzi, most important drugs licensed for Chagas disease treatment are reviewed: nifurtimox and benznidazol, their mechanisms of action, doses, treatment schedules, adverse effects and contraindications. Two other drugs used for Chagas disease treatment, for which a Chilean experience may be exhibited, are allopurinol and itraconazole. Indications for treatment of Chagas disease in immunocompetent patients and immunocompromised hosts are detailed. This chapter refers besides to the evaluation and monitoring of antiparasitic therapy in immunocompromised patients, the availability of drugs and includes various forms facsimiles suggested to perform clinical and laboratory follow up of patients that undergo treatment, indicating the prescribed drug, adverse effects and time of follow up.

Topics: Allopurinol; Animals; Chagas Disease; Follow-Up Studies; Humans; Immunocompromised Host; Immunosuppressive Agents; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Benznidazole (Bz) and Nifurtimox (Nfx) have been used to treat Chagas disease. As recent studies have de-monstrated cardiotoxic effects of Nfx, we attempted to determine whether Bz behaves similarly. Bz reached the heart tissue of male rats after intragastric administration. No cytosolic Bz nitroreductases were detected, although microsomal NADPH-dependent Bz nitroreductase activity was observed, and appeared to be mediated by P450 reductase. No ultrastructurally observable deleterious effects of Bz were detected, in contrast to the overt cardiac effects previously reported for Nfx. In conclusion, when these drugs are used in chagasic patients, Bz may pose a lesser risk to heart function than Nfx when any cardiopathy is present.

Topics: Animals; Biotransformation; Drug Evaluation, Preclinical; Heart; Male; Microscopy, Electron, Transmission; Microsomes; Myocardium; Nifurtimox; Nitroimidazoles; Nitroreductases; Rats; Rats, Sprague-Dawley; Time Factors; Trypanocidal Agents

Nifurtimox and benznidazole are the front-line drugs used to treat Chagas disease, the most important parasitic infection in the Americas. These agents function as prodrugs and must be activated within the parasite to have trypanocidal effects. Despite >40 years of research, the mechanism(s) of action and resistance have remained elusive. Here, we report that in trypanosomes, both drugs are activated by a NADH-dependent, mitochondrially localized, bacterial-like, type I nitroreductase (NTR), and that down-regulation of this explains how resistance may emerge. Loss of a single copy of this gene in Trypanosoma cruzi, either through in vitro drug selection or by targeted gene deletion, is sufficient to cause significant cross-resistance to a wide range of nitroheterocyclic drugs. In Trypanosoma brucei, loss of a single NTR allele confers similar cross-resistance without affecting growth rate or the ability to establish an infection. This potential for drug resistance by a simple mechanism has important implications, because nifurtimox is currently undergoing phase III clinical trials against African trypanosomiasis.

Topics: Animals; Drug Resistance; Gene Expression Regulation; Genome, Protozoan; Mitochondria; Nifurtimox; Nitroimidazoles; Nitroreductases; Phenotype; Protozoan Proteins; Trypanocidal Agents; Trypanosoma cruzi

It has been more than 25 years since it was first reported that nifurtimox and benznidazole promote superoxide production in trypanosomes. However, there has been no direct evidence of an association between the drug-induced free radicals and trypanocidal activity. Here, we identify a superoxide dismutase required to protect Trypanosoma brucei from drug-generated superoxide.

Topics: Animals; Gene Deletion; Genes, Protozoan; Nifurtimox; Nitroimidazoles; Parasitic Sensitivity Tests; Superoxide Dismutase; Trypanosoma brucei brucei

The trypanocidal activity of N-allyl (NAOx) and N-propyl (NPOx) oxamates and that of the ethyl esters ofN-allyl (Et-NAOx) and N-propyl (Et-NPOx) oxamates were tested on cultured epimastigotes (in vitro) and murine trypanosomiasis (in vivo) using five different T. cruzi strains. NAOx and NPOx did not penetrate intact epimastigotes and therefore we were not able to detect any trypanocidal effect with these oxamates. Whereas the ethyl esters (Et-NAOx and Et-NPOx), acting as prodrugs, exhibited in vitro and in vivo trypanocidal activity on the five tested T. cruzi strains. On the contrary, when Nifurtimox and Benznidazole used as reference drugs were tested, we found that only three of the five tested T cruzi strains were affected, whereas the other two strains, Miguz and Compostela, were resistant to the in vitro and in vivo trypanocidal activity of these compounds.

Topics: Animals; Chagas Disease; Mice; Nifurtimox; Nitroimidazoles; Oxamic Acid; Trypanocidal Agents; Trypanosoma cruzi

Chagas' disease, caused by the parasite Trypanosoma cruzi, remains the leading cause of cardiopathy in Latin America with about 12 million people infected. Classic clinical manifestations derive from infection of muscle cells leading to progressive cardiomyopathy, while some patients develop megacolon or megaesophagus. A very aggressive clinical course including fulminant meningoencephalitis has been reported in patients who contract Chagas' disease in the background of immunodeficiency. This includes patients with human immunodeficiency virus infection as well as patients receiving immunosuppressive therapy for organ transplant. Currently, only two drugs are approved for the treatment of Chagas' disease, nifurtimox and benznidazole. Both have significant limitations due to common and serious side effects as well as limited availability. A promising group of new drug leads for Chagas' disease is cysteine protease inhibitors targeting cruzain, the major protease of T. cruzi. The inhibitor N-methyl-Pip-F-homoF-vinyl sulfonyl phenyl (N-methyl-Pip-F-hF-VS phi) is in late-stage preclinical development. Therefore, the question arose as to whether protease inhibitors targeting cruzain would have efficacy in Chagas' disease occurring in the background of immunodeficiency. To address this question, we studied the course of infection in recombinase-deficient (Rag1(-/-)) and normal mice infected with T. cruzi. Infections localized to heart and skeletal muscle in untreated normal animals, while untreated Rag1(-/-) mice showed severe infection in all organs and predominantly in liver and spleen. Treatment with the dipeptide N-methyl-Pip-F-hF-VS phi rescued immunodeficient animals from lethal Chagas' infection. The majority (60 to 100%) of inhibitor-treated Rag1(-/-) mice had increased survival, negative PCR, and normal tissues by histopathological examination.

Topics: Animals; Cattle; Cells, Cultured; Chagas Disease; Cysteine Endopeptidases; Cysteine Proteinase Inhibitors; Disease Models, Animal; Female; Homeodomain Proteins; Humans; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Knockout; Nifurtimox; Nitroimidazoles; Protozoan Proteins; Survival Analysis; Trypanocidal Agents; Trypanosoma cruzi

Old yellow enzyme (OYE) is a NAD(P)H flavin oxidoreductase that in Trypanosoma cruzi (TcOYE) catalyzes prostaglandin PGF2alpha synthesis and reduction of some trypanocidal drugs. We performed DNA microarray analysis and it revealed that the levels of transcription of the TcOYE gene were six-fold lower in a T. cruzi population with in vitro-induced resistance to benznidazole (BZ) (17LER) than in the wild-type (17WTS). Further we investigated the TcOYE levels in 15 T. cruzi strains and clones that were either susceptible or naturally resistant to BZ and nifurtimox, or had in vivo-selected resistance to BZ. Northern blot and real-time RT-PCR analyses confirmed our finding that TcOYE transcription levels were lower in 17LER than in 17WTS. In contrast, we detected no differences in TcOYE transcription levels between other T. cruzi samples. All T. cruzi strains contained four copies of TcOYE gene, except 17LER that contained only one. A 42kDa TcOYE protein was detected in all T. cruzi strains tested. The expression of this protein was similar for all samples, with the exception of 17LER for which the protein was nearly seven-fold less expressed. The chromosomal location of the TcOYE gene and the polymorphisms detected in TcOYE nucleotide and amino acid sequences of the T. cruzi strains are associated with the zymodeme but not with drug-resistance phenotype. Our data show that one of the mechanisms conferring in vitro-induced BZ resistance to T. cruzi correlates with deletion of copies of the TcOYE gene. In contrast, the in vivo and natural resistance to BZ are mediated by different mechanisms.

Topics: Animals; Antifungal Agents; Blotting, Northern; DNA, Fungal; Drug Resistance, Fungal; Fungal Proteins; Gene Deletion; Gene Dosage; Gene Expression Profiling; Molecular Sequence Data; Molecular Weight; NADPH Dehydrogenase; Nifurtimox; Nitroimidazoles; Oligonucleotide Array Sequence Analysis; Polymorphism, Genetic; Reverse Transcriptase Polymerase Chain Reaction; RNA, Fungal; RNA, Messenger; Sequence Analysis, DNA; Sequence Homology; Trypanosoma cruzi

A quantitative colorimetric assay using the oxidation-reduction indicator resazurin was developed to measure cytotoxicity of compounds against the protozoan parasite Trypanosoma cruzi. This method is based on the detection of colorimetric changes caused by the oxidation (blue) and reduction (pink) capabilities of resazurin dye, an indicator for metabolic cell function. To validate the assay, the experimental conditions were adjusted, such as number of parasites, dye concentration, and time of incubation, with respect to linearity and lower limit of detection. We found that absorbances increased linearly, with the plating density of parasites as low as 5-100 x 10(4)/well (r=0.99; p<0.001) when they were incubated for 5 h at 28 degrees C in the presence of 10% resazurin solution (3 mM). When the cytotoxicity of the reference drugs nifurtimox and benznidazole was measured with this assay and compared to the microscopic counting method, the same range was obtained, demonstrating that the resazurin microtiter assay is valid for the screening of new trypanocidal compounds. This test is very simple, fast, sensitive, and cheap.

Topics: Animals; Colorimetry; Humans; Indicators and Reagents; Nifurtimox; Nitroimidazoles; Oxazines; Oxidation-Reduction; Parasitic Sensitivity Tests; Sensitivity and Specificity; Trypanocidal Agents; Trypanosoma cruzi; Xanthenes

Topics: Animals; Chagas Disease; Child; Diagnosis, Differential; Humans; Nifurtimox; Nitroimidazoles; Poverty; Risk Factors; Trypanocidal Agents; Trypanosoma cruzi

l-Buthionine (S,R)-sulfoximine (BSO) increased the toxicity of nifurtimox and benznidazole toward the epimastigote, trypomastigote, and amastigote forms of Trypanosoma cruzi. BSO at 500 muM decreased total glutathione-derived thiols by 70 to 80% in 48 h. In epimastigotes, 500 muM BSO decreased the concentration of nifurtimox needed to inhibit constant growth of the parasites by 50%, from 14.0 to 9.0 muM, and decreased that of benznidazole from 43.6 to 24.1 muM. The survival of epimastigotes or trypomastigotes treated with nifurtimox or benznidazole, as measured by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) reduction, was significantly decreased by 500 muM BSO. In Vero cells infected with amastigotes, 25 muM BSO was able to potentiate the effect of nifurtimox and benznidazole as measured by the percentage of infected Vero cells multiplied by the average number of intracellular amastigotes (endocytic index). At 0.5 muM nifurtimox, the proportion of Vero cells infected decreased from 27 to 20% and the endocytic index decreased from 2,500 to 980 when 25 muM BSO was added. Similar results were obtained with benznidazole- and BSO-benznidazole-treated cells. This study indicates that potentiation of nifurtimox or benznidazole by BSO could decrease the clinical dose of both drugs and diminish the side effects or the length of therapy.

Topics: Animals; Buthionine Sulfoximine; Chlorocebus aethiops; Drug Synergism; Nifurtimox; Nitroimidazoles; Parasitic Sensitivity Tests; Trypanocidal Agents; Trypanosoma cruzi; Vero Cells

We have developed a new pharmacological screening assay for epimastigotes of Trypanosoma cruzi (clone CL-B5) that express the Escherichia coli LacZ gene. The assay is based on determining the activity of the cytoplasmic beta-galactosidase released into the culture on membrane lysis in the presence of the substrate chlorophenol red beta-D-galactopyranoside (CPRG). The experimental conditions were adjusted to find those in which the relationship between epimastigote number and CPRG absorbance was linear over the widest possible range. Absorbance was significantly correlated with the number epimastigote from 5x10(3) to 1.2x10(6) parasites/ml (r=0.98, P<0.01). The optimal final concentration of CPRG was 200 microM and the optimal incubation period was 6 h when parasites were incubated for 3 days. Once the assay was standardized, the trypanocidal activities of nifurtimox and benznidazole were determined both by CPRG assay and microscopic counting, demonstrating the methods utility for drug-screening. The efficacy obtained was comparable to that obtained with the manual method.

Topics: Animals; beta-Galactosidase; Chlorophenols; Galactosides; Lac Operon; Nifurtimox; Nitroimidazoles; Parasitic Sensitivity Tests; Spectrophotometry; Trypanocidal Agents; Trypanosoma cruzi

The trypanocidal activity of N-isopropyl oxamate (NIPOx) and the ethyl ester of N-isopropyl oxamate (Et-NIPOx) were tested on cultured epimastigotes (in vitro) and on murine trypanosomiasis (in vivo) using five different T. cruzi strains. When benznidazole and nifurtimox, used for comparison, were tested we found that only three of these T. cruzi strains were affected, whereas the other two strains, Miguz and Compostela, were resistant to the in vitro and the in vivo trypanocidal activity of these substances. In addition, when NIPOx was tested on cultured epimastigotes and on mice parasitaemia, trypanocidal activity was not obtained on either of these T. cruzi strains. Our experiments strongly suggest that NIPOx does not penetrate intact epimastigotes due to the polarity of its carboxylate whereas Et-NIPOx, acting as a prodrug, exhibited in vitro and in vivo trypanocidal activity in the five tested T. cruzi strains.

Topics: Alcohol Oxidoreductases; Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme Inhibitors; Kinetics; Mice; Models, Chemical; NAD; Nifurtimox; Nitroimidazoles; Oxamic Acid; Species Specificity; Time Factors; Trypanocidal Agents; Trypanosoma cruzi; Trypanosomiasis

Topics: Chagas Disease; Humans; Infant, Newborn; Infant, Newborn, Diseases; Infectious Disease Transmission, Vertical; Nifurtimox; Nitroimidazoles; Patient Compliance; Trypanocidal Agents

Proteins rich in sulfhydryl groups, such as metallothionein, are present in several strains of the parasite Trypanosoma cruzi, the etiological agent of Chagas' disease. Metallothionein-like protein concentrations ranged from 5.1 to 13.2 pmol/mg protein depending on the parasite strain and growth phase. Nifurtimox and benznidazole, used in the treatment of Chagas' disease, decreased metallothionein activity by approximately 70%. T. cruzi metallothionein was induced by ZnCl2. Metallothionein from T. cruzi was partially purified and its monobromobimane derivative showed a molecular weight of approximately 10,000 Da by SDS-PAGE analysis. The concentration of trypanothione, the major glutathione conjugate in T. cruzi, ranged from 3.8 to 10.8 nmol/mg protein, depending on the culture phase. The addition of buthionine sulfoximine to the protozoal culture considerably reduced the concentration of trypanothione and had no effect upon the metallothionein concentration. The possible contribution of metallothionein-like proteins to drug resistance in T. cruzi is discussed.

Topics: Animals; Buthionine Sulfoximine; Electrophoresis, Polyacrylamide Gel; Glutathione; Metallothionein; Nifurtimox; Nitroimidazoles; Protozoan Proteins; Spermidine; Time Factors; Trypanocidal Agents; Trypanosoma cruzi

Albaconazole is an experimental triazole derivative with potent and broad-spectrum antifungal activity and a remarkably long half-life in dogs, monkeys, and humans. In the present work, we investigated the in vivo activity of this compound against two strains of the protozoan parasite Trypanosoma (Schizotrypanum) cruzi, the causative agent of Chagas' disease, using dogs as hosts. The T. cruzi strains used in the study were previously characterized (murine model) as susceptible (strain Berenice-78) and partially resistant (strain Y) to the drugs currently in clinical use, nifurtimox and benznidazole. Our results demonstrated that albaconazole is very effective in suppressing the proliferation of the parasite and preventing the death of infected animals. Furthermore, the parasitological, PCR, serological, and proliferative assay results indicated parasitological cure indices of 25 and 100% among animals inoculated with T. cruzi strain Y when they were treated with albaconazole at 1.5 mg/kg of body weight/day for 60 and 90 days, respectively. On the other hand, although albaconazole given at 1.5 mg/kg/day was very effective in suppressing the proliferation of the parasite in animals infected with the Berenice-78 T. cruzi strain, no parasitological cure was observed among them, even when a longer treatment period (150 doses) was used. In conclusion, our results demonstrate that albaconazole has trypanocidal activity in vivo and is capable of inducing radical parasitological cure, although natural resistance to this compound was also indicated. Furthermore, the compound can be used in long-term treatment schemes (60 to 150 days) with minimal toxicity and thus represents a potentially useful candidate for the treatment of human Chagas' disease.

Topics: Animals; Chagas Disease; Dogs; Enzyme-Linked Immunosorbent Assay; Immunoglobulin G; Monocytes; Nifurtimox; Nitroimidazoles; Quinazolines; Reverse Transcriptase Polymerase Chain Reaction; Triazoles; Trypanocidal Agents; Trypanosoma cruzi

The Diels-Alder reaction between two polygodial-derived dienes and simple quinones to yield substituted naphtho- and anthraquinones, is described. The in vitro trypanocide activity for the series was determined. Two of the new compounds showed an activity ten and two times higher, respectively, than nifurtimox and benznidazole, the medicines of choice for the treatment of the acute Chagas' disease.

Topics: Animals; Inhibitory Concentration 50; Nifurtimox; Nitroimidazoles; Polycyclic Compounds; Polycyclic Sesquiterpenes; Quinones; Sesquiterpenes; Trypanocidal Agents; Trypanosoma cruzi

The effect of N-isopropyl oxamate on the activity of alpha-hydroxyacid dehydrogenase-isozyme II (HADH-isozyme II) from Trypanosoma cruzi was investigated. The kinetic studies showed that this substance was a competitive inhibitor of this isozyme. The attachment of the nonpolar isopropylic branched chain to the nitrogen of oxamate increased 12-fold the affinity of N-isopropyl oxamate for the active site of T. cruzi HADH-isozyme II. N-isopropyl oxamate was a selective inhibitor of HADH-isozyme II, since other T. cruzi dehydrogenases were not inhibited by this substance. Since HADH-isozyme II participates in the energy metabolism of T. cruzi, a trypanocidal effect can be expected with inhibitors of this isozyme. However, although it was not possible to detect any trypanocidal activity with N-isopropyl oxamate when the ethyl ester was tested as a possible trypanocidal prodrug, the expected trypanocidal effect was obtained, comparable to that obtained with nifurtimox and benznidazole.

Topics: Alcohol Oxidoreductases; Animals; Dose-Response Relationship, Drug; Kinetics; Models, Chemical; Nifurtimox; Nitroimidazoles; Oxamic Acid; Prodrugs; Protein Isoforms; Time Factors; Trypanocidal Agents; Trypanosoma cruzi

Clone CL B5 of Trypanosoma cruzi is a beta-galactosidase expressing organism that was genetically transfected to be used for in vitro pharmacological screening. Biological parameters were determined, evaluating growth kinetics of epimastigotes, metacyclogenesis, infectivity to mammalian cell lines, parasitemia kinetics in mice and sensibility to nifurtimox and benznidazole. Differences in relation to other strains and CL parental strain were found, the most important being the incapability to produce death to mice in spite of the high inoculum used. However, it possesses the required features to be used for in vitro drug screening. Data obtained demonstrate that heterogeneity of T. cruzi appears even among clones of the same strain, and that these differences found do not prevent the use of clone CL B5 for the purpose that was engineered.

Topics: Animals; beta-Galactosidase; Chlorocebus aethiops; Cloning, Organism; Mice; Nifurtimox; Nitroimidazoles; Parasitic Sensitivity Tests; Trypanocidal Agents; Trypanosoma cruzi; Vero Cells

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B; ATP-Binding Cassette Transporters; Chagas Disease; Drug Resistance; Gene Amplification; Glycoproteins; Humans; Karyotyping; Mice; Nifurtimox; Nitroimidazoles; Parasitic Sensitivity Tests; Polymorphism, Restriction Fragment Length; Protozoan Proteins; Trypanocidal Agents; Trypanosoma cruzi

In this study is presented the comparative therapeutical experience comparing the Allopurinol, Benznidazol y Nifurtimox, in a prospective following in a long term, considering the responses to the parasitemia, specific serology and evolution of the clinic manifestations and complementaries in the 535 chronic chagasic cases (44.5%), instead of 668 patients who did not get any treatment (1203 chagasic cases followed for more than 5 years average). This study was done between April 1984 and April 1994 in patients with and without cardiopathy, in the Córdoba Hospital and the Salud Estudiantil Direccion, Universidad Nacional de Córdoba (U.N.C.); from them, 309 patients were given Allopurinol, 130 were given Benznidazol, and 96 were given Nifurtimox, with usual doses of Benznidazol and Nifurtimox, but with Allopurinol it was made an study evaluating the answering-doses, with a following time of post-therapeutic average of 55.6 months (D.S. = + -57 m.) The comparative parameters were the starting clinic characteristics, the qualitative and quantitative for Chagas, the pre-treatment xerodiagnostic, the treatment fulfillment, the treatment duration, the adverse effects, the treatment abandon, the time of postreatment longitudinal following till the last clinic-complementary evaluation, the clinic characteristics at the end of the following period; quantitative and qualitative serology for Chagas after the treatment, and post-treatment xerodiagnostic. It was observe a prevalence of Electrocardiographic Changes in the ECG in rest, in the first complementary evaluation in 76 of the 535 "Treated" and in the 225 "No-treated" patients, being Electrocardiographic abnormality proportion much more in the "No-treated" patients (P = 0.000000). After the end of the following period it was thought to have been found Miocardic Damage Progression in 120 patients "No-treated" and in 31 "Treated" patients (17.9% and 5.8% respectively) (P = 0.0000000). The complications in the evolution course were proved in 113 of the "No-treated" and in 19 of the "Treated" patients (16.9% and 3.5%, being this a statistically significant difference (P = 0.0000000). The mortality along the evolution was proved in 37 of the "No-Treated:" patients and in 7 of the "Treated" patients (5.5% and 1.3%), being this a statistically significant difference (P = 0.00019). The most tolerated drug and the one with the least incidence of therapeutic abandons was the Allopurinol. The xerodiagnostic negativization

Topics: Adolescent; Adult; Aged; Allopurinol; Antiprotozoal Agents; Chagas Cardiomyopathy; Chagas Disease; Female; Follow-Up Studies; Humans; Male; Middle Aged; Nifurtimox; Nitroimidazoles; Prospective Studies; Retrospective Studies; Time Factors; Treatment Outcome; Trypanocidal Agents

We designed a set of procedures for first-line local health services to detect and treat the congenital transmission of Trypanosoma cruzi at a province-wide scale, and field-tested the programme in the province of Tucumán, northwestern Argentina, from 1992 to 1994. The programme consists of routine screening of pregnant women for seroreactivity to T. cruzi, serological and parasitological follow-up of the newborn at least twice during the first year of age, treatment of the infected infants, and evaluation of the outcome. 927 (5.5%) of 16 842 pregnant women were seroreactive to T. cruzi by indirect haemagglutination assay and ELISA. Twenty-one (6.7%) of 315 newborns to seroreactive mothers were diagnosed as infected with T. cruzi parasites microhaematocrit concentration before 30 days of age. Five newborns who initially tested negative had a T. cruzi infection detected by microhaematocrit and/or serological techniques at 3 or 6 months of age. Thus, congenital infection was diagnosed in 26 (7.1%) infants born to seroreactive women and residing in houses free of triatomine bugs. Four of 6 infants born to seroreactive mothers died during the first year of age and had some evidence of T. cruzi infection; one of the deaths was attributed to T. cruzi based on clinical evidence. After specific treatment with nifurtimox or benznidazole, 30 of 32 infants remained parasitologically and serologically negative. This study shows the feasibility of controlling the incidence of congenitally acquired T. cruzi infections at a province-wide scale by means of a specific screening programme at first-line health services level.

Topics: Adult; Animals; Argentina; Chagas Disease; Enzyme-Linked Immunosorbent Assay; Female; Hemagglutination Tests; Humans; Infant; Infant, Newborn; Infectious Disease Transmission, Vertical; Middle Aged; Nifurtimox; Nitroimidazoles; Pregnancy; Pregnancy Complications, Parasitic; Trypanocidal Agents

The therapeutic potential of synthetic inhibitors to the major cysteine-proteinase from Trypanosoma cruzi (cruzain or cruzipain) was recently demonstrated in animal models of Chagas' disease. A possible limitation of this strategy would be the emergence of parasite populations developing resistance to cysteine-proteinase inhibitors. Here, we describe the properties of a phenotypically stable T. cruzi cell line (R-Dm28) that displays increased resistance to Z-(SBz)Cys-Phe-CHN2, an irreversible cysteine-proteinase inhibitor which preferentially inactivates cathepsin L-like enzymes. Isolated from axenic cultures of the parental cells (IC50 1.5 microM), R-Dm28 epimastigotes exhibited 13-fold (IC50) 20 microM) higher resistance to this inhibitor and did not display cross-resistance to unrelated trypanocidal drugs, such as benznidazol and nifurtimox. Western blotting (with mAb), affinity labeling (with biotin-LVG-CHN2) and FACS analysis of R-Dm28 log-phase epimastigotes revealed that the cruzipain target was expressed at lower levels, as compared with Dm28c. Interestingly, this deficit was paralleled by increased expression of an unrelated Mr 30 000 cysteine-proteinase whose activity was somewhat refractory to inhibition by Z-(SBz)Cys-Phe-CHN,. N-terminal sequencing of the affinity-purified biotin-LVG-proteinase complex allowed its identification as a cathepsin B-like enzyme. Increased antigenic deposits of this proteinase were found in the grossly enlarged and electron dense reservosomes from R-Dm28 epimastigotes. Our data suggest that R-Dm28 resistance to toxic effects induced by the synthetic inhibitor may result from decreased availability of the most sensitive cysteine-proteinase target, cruzipain. The deficit in metabolic functions otherwise mediated by this cathepsin L-like proteinase is likely compensated by increased expression/accumulation of a cathepsin B-like target.

Topics: Animals; Antigens, Protozoan; Cathepsin B; Cell Line; Cysteine Endopeptidases; Cysteine Proteinase Inhibitors; Drug Resistance, Microbial; Flow Cytometry; Glycoproteins; Immunoblotting; Immunohistochemistry; Nifurtimox; Nitroimidazoles; Protozoan Proteins; Trypanocidal Agents; Trypanosoma cruzi

The method most commonly used in screening of drugs for the treatment of Chagas' disease, microscopic counting of viable trypanosomes, is time-consuming, labor-intensive, and dependent on the observer. Although the tetrazolium dye [MTT; 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay is comparatively quick and accurate, it requires careful attention in design as well as in interpretation of the results. Therefore, we examined under various conditions the sensitivity and specificity of the MTT assay versus microscopic counting for determination of the viability of Trypanosoma cruzi for drug-screening purposes. We tested different concentrations of MTT in phenazine methosulfate (PMS) against T. cruzi epimastigotes of the Y strain in different stages of logarithmic growth. In our model, in tests of benznidazole and nifurtimox the optimal concentration of MTT was 2.5 mg/ml of PMS and the optimal incubation period was 75 min. This method detected parasite concentrations of approx. 500,000 epimastigotes/ml (P<0.01), and the linear correlation between absorbance values and numbers of epimastigotes per milliliter was very strong (approx. R = 0.99). The present MTT assay results in faster determination of the activity of compounds, is more objective, and enables testing of several drugs simultaneously.

Topics: Animals; Colorimetry; Culture Media; Nifurtimox; Nitroimidazoles; Oxidation-Reduction; Parasitic Sensitivity Tests; Sensitivity and Specificity; Tetrazolium Salts; Thiazoles; Trypanocidal Agents; Trypanosoma cruzi

We have identified previously a Trypanosoma cruzi gene encoding a protein named Tc52 sharing structural and functional properties with the thioredoxin and glutaredoxin protein family involved in thiol-disulphide redox reactions. Furthermore, we have reported that Tc52 also played a role in T. cruzi-associated immunosuppression observed during Chagas' disease. In an effort to understand further the biological role of Tc52, we used a gene-targeted deletion strategy to create T. cruzi mutants. Although T. cruzi tolerates deletion of one wild-type Tc52 allele, deletion of both genes is a lethal event, indicating that at least one active Tc52 gene is required for parasite survival. Monoallelic disruption of Tc52 (Tc52+/-) resulted in the production of T. cruzi lines that express less Tc52 mRNA and produced lower amounts of Tc52 protein compared with wild-type cells. In axenic cultures, growth rates of epimastigote forms bearing an interrupted allele were not different from those of wild-type parasites. Furthermore, monoallelic disruption of the Tc52 gene did not modify the growth rate of epimastigotes or their sensitivity to inhibition by benznidazole and nifurtimox, the two drugs used to treat Chagasic patients. Moreover, the antimonial drug SbIII, which is known, at least in Leishmania parasites, to be conjugated to a thiol and extruded by an ATP-coupled pump, had a similar effect on wild-type and mutant parasites, being equally sensitive. Hence, parasite drug sensitivity was also observed in clones overexpressing the Tc52 protein as well as in those carrying an antisense plasmid construct. Surprisingly, a significant impairment of the ability of epimastigotes carrying a Tc52 single gene replacement or antisense construct to differentiate into metacyclic trypomastigotes and to proliferate in vitro and in vivo was observed, whereas no significant enhancement of these biological properties was seen in the case of parasites that overexpress Tc52 protein. Moreover, functional complementation of Tc52+/- single mutant or selection of antisense revertant clones demonstrated that the phenotype observed is a direct consequence of Tc52 gene manipulation. Taken together, these results may suggest that Tc52 could participate among other factors in the phenotypic expression of T. cruzi virulence.

Topics: Alleles; Amino Acid Sequence; Animals; Antimony; Base Sequence; DNA, Protozoan; Gene Deletion; Macrophages; Metals, Heavy; Molecular Sequence Data; Nifurtimox; Nitroimidazoles; Oligonucleotides, Antisense; Phenotype; Protozoan Proteins; Transcription, Genetic; Trypanocidal Agents; Trypanosoma cruzi

In a search for antichagasic drugs, 14 new 4-(nitroarylidene)-1,2,6-thiadiazin-3,5-dione 1,1-dioxide derivatives were synthesized and tested in vitro against the epimastigote form of Trypanosoma cruzi and some of them showed important antiprotozoan activity. Attempts to synthesize new 4-(nitroarylidene)-3,5-diamino-1,2,6-thiadiazine 1,1-dioxides were unsuccessful. The antichagasic properties of nitroarylidene-malononitrile and nitroarylidene-cyanoacetamide derivatives, thus obtained, were also tested. The cytotoxic properties against Vero cells of compounds which showed remarkable in vitro antichagasic activity were evaluated. All compounds tested exhibited high toxicity percentages at 100 micrograms/ml. However, compound 3c showed in vitro antichagasic and cytotoxic properties such as nifurtimox at the dose of 10 micrograms/ml.

Topics: Animals; Chlorocebus aethiops; Humans; Magnetic Resonance Spectroscopy; Nifurtimox; Nitroimidazoles; Spectrophotometry, Infrared; Thiadiazines; Trypanocidal Agents; Trypanosoma cruzi; Vero Cells

Topics: AIDS-Related Opportunistic Infections; Chagas Disease; Humans; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

Trypanosoma cruzi populations are subdivided into natural clones that can exhibit considerable genetic differences. It has been proposed that T. cruzi clonal structure has a major impact on this parasite's biological properties. The present work aims at testing this hypothesis. Twenty-one stocks isolated from various ecological cycles, places, and hosts were characterized by multilocus enzyme electrophoresis (MLEE) with 22 genetic loci and random amplification of polymorphic DNA (RAPD) with 10 primers on the one hand and by 14 different biological parameters on the other hand. These parameters were related to: (i) growth kinetics of epimastigotes and amastigotes; (ii) infection of culture cells by amastigotes; (iii) viability of extracellular trypomastigotes; or (iv) sensitivity of epimastigotes, trypomastigotes, and amastigotes to Benznidazole and Nifurtimox. MLEE and RAPD results exhibited parity to each other, as previously noted (M. Tibayrenc, K. Neubauer, C. Barnabé, F. Guerrini, D. Skarecky, and F. J. Ayala, 1993, Proceedings of the National Academy of Sciences of the USA 90, 1335-1339), and showed that the 21 stocks were distributed into three main genetic groups, 19/20, 32, and 39, corresponding to the major clones 19, 20, 32, and 39 previously described on the basis of 15 isozyme loci. Most biological parameters showed a strong correlation to the genetic distances evaluated from either MLEE or RAPD, which favors the working hypothesis. The only exception came from drug sensitivity estimated on trypomastigote forms. The overall results made it possible to firmly reject the null hypothesis that there is no relationships between evolutionary distances and biological differences in T. cruzi natural clones.

Topics: Animals; Biological Evolution; Chagas Disease; Chlorocebus aethiops; Cluster Analysis; Discriminant Analysis; DNA, Protozoan; Electrophoresis, Cellulose Acetate; Genetic Variation; Genotype; Humans; Isoenzymes; Monte Carlo Method; Nifurtimox; Nitroimidazoles; Phylogeny; Random Amplified Polymorphic DNA Technique; Trypanocidal Agents; Trypanosoma cruzi; Vero Cells

Twenty-seven Trypanosoma cruzi strains, susceptible or naturally resistant to the nitroderivatives benznidazole and nifurtimox, were analyzed using the following molecular markers: (i) isoenzyme patterns of six enzymes; (ii) genetic variability assayed by randomly amplified polymorphic DNA (RAPD) with two different primers; and (iii) gene probes for P-glycoprotein (TcPGP), hypoxanthine-guanine phosphoribosyltransferase (HGPRT), the ribosomal RNA gene (rDNA) and the mini-exon gene (MEX), RAPD and isoenzyme profiles divided the T. cruzi strains into three groups, whereas the gene probes divided the T. cruzi strains in two groups. Strains classified as group I or II by RAPD or zymodemes Z1 or Z2 by isoenzyme analysis were either susceptible or naturally resistant to the nitroderivatives. In contrast, strains classified as group III by RAPD and zymodeme ZB by isoenzyme analysis were only drug susceptible and showed polymorphisms for HGPRT and TcPGP. No correlation was observed between drug susceptibility and polymorphisms of rDNA and MEX. Eighteen T. cruzi strains isolated from different geographic regions were included in this study. Thus, from a total of 45 T. cruzi strains analyzed, all 19 of zymodeme B were susceptible to the experimental treatment independent of their geographic origin.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Brazil; Chagas Disease; DNA, Protozoan; DNA, Ribosomal; Drug Resistance; Exons; Genes, Protozoan; Genetic Variation; Glucose-6-Phosphate Isomerase; Humans; Hypoxanthine Phosphoribosyltransferase; Isoenzymes; Nifurtimox; Nitroimidazoles; Polymorphism, Genetic; Random Amplified Polymorphic DNA Technique; Trypanocidal Agents; Trypanosoma cruzi

Screening of candidate trypanocidal compounds or factors affecting invasion of mammalian cells by the infective stages of Trypanosoma cruzi in tissue culture models has primarily involved labor-intensive microscopic counting of the parasites. A very efficient method for quantitating the inhibitory effect of antimicrobial agents or signaling pathways inhibitors on T. cruzi grown in L6E9 myoblasts was devised. This assay takes advantage of the selective incorporation of [3H]uracil into nucleic acids by replicating T. cruzi amastigotes. L6E9 rat myoblasts are submitted to gamma irradiation to inhibit their replication. Uracil uptake by uninfected cells is considerably decreased by this method. Nifurtimox, benznidazole, fexinidazole, MK-436, and megazol are drugs known to have activity against T. cruzi and were used in growth inhibition assays. The results demonstrated that [3H]uracil incorporation in the presence of different concentrations of nifurtimox and benznidazole closely correlated with the number of amastigotes per 100 myoblasts in Giemsa-stained monolayers under the conditions used. This method also has the advantage to differentiate between the effects of the compounds on the invasion and the replication steps of the infection with T. cruzi, as shown by the inhibitory effect of genistein when added in invasion assays.

Topics: Animals; Cells, Cultured; DNA Replication; DNA, Protozoan; Drug Evaluation, Preclinical; Drug Resistance; Gamma Rays; Muscle, Skeletal; Nifurtimox; Nitroimidazoles; Rats; Reproduction; Thiadiazoles; Trypanocidal Agents; Trypanosoma cruzi; Uracil

Topics: Animals; Glutathione; Nifurtimox; Nitroimidazoles; Spermidine; Sulfhydryl Compounds; Trypanocidal Agents; Trypanosoma cruzi

In previous studies, molecular and immunological approaches have been used to characterize the Trypansosoma cruzi elongation factor 1gamma (TcEF-1gamma). A primary sequence homology search revealed that the TcEF-1gamma N-terminal domain showed significant homology to glutathione S-transferases (GSTs). Although studies have suggested the involvement of EF-1gamma in the protein synthesis machinery, the exact function of this protein, particularly the role of its GST-like domain, is not fully understood. Therefore, we have used the protozoan parasite T. cruzi, as a recipient for a shuttle vector which allows overexpression of TcEF-1gamma in order to gain insight into its biological function. The growth of parasites which overexpress TcEF-1gamma and control cells was equally sensitive to inhibition by nifurtimox and benznidazole, which exert a trypanocidal activity through the production of free radicals. In contrast, a strong resistance of transformed organisms to the tricyclic antidepressant drug, clomipramine, a lipophilic compound, was observed, whereas control cells were highly sensitive. Our findings suggest that TcEF-1gamma participates in the detoxification of lipophilic compounds probably by conjugation with glutathione through its GST-like domain. To our knowledge, this is the first report showing that the eukaryotic EF-1gamma GST conserved enzymatic model could play a role in drug resistance. Furthermore, these results reinforce the notion that the aggressiveness of certain tumours could in part be linked to overexpression of EF-1gamma. They also raise a central question regarding the GST as target for chemotherapeutic drugs in cancer research.

Topics: Animals; Clomipramine; DNA, Complementary; Drug Resistance; Glutathione Transferase; Nifurtimox; Nitroimidazoles; Peptide Elongation Factor 1; Peptide Elongation Factors; Phenotype; Trypanocidal Agents; Trypanosoma cruzi

Glutathione (GSH), trypanothione (T(SH)2) and glutathionyl spermidine (GSH-SP) concentrations were determined in the Tulahuén and LQ strains and the DM 28c clone of Trypanosoma cruzi. The concentrations of GSH, T(SH)2 and GSH-SP, expressed as nmol of GSH per g of parasite fresh weight, were 60.1, 397.8 and 103.9, respectively, for the Tulahuén strain. For the DM 28c clone, the values were 113.9, 677.9 and 164.1, respectively, and for the LQ strain they were 199.1, 1100.5 and 55.3, respectively. When the parasites were treated with 10 microM nifurtimox or 50 microM benznidazole for 2 h, the concentrations of all three reduced thiols decreased strongly. The total amount of T(SH)2 decreased by more than 50%. Treatment of the parasites with 5 mM buthionine sulfoximine, an inhibitor of GSH synthesis, for 6 h diminished the concentrations of the reduced thiols by between 27% and 53% with respect to the controls. Cyclohexylamine, an inhibitor of spermidine synthesis, decreased the concentrations of T(SH)2 and GSH-SP but not that of GSH. It is possible to conclude from this study that trypanothione is the most important thiol involved in the detoxication of nifurtimox and benznidazole in T. cruzi and that electrophilic reduced metabolites of both drugs are most probably conjugated with GSH, T(SH)2 and GSH-SP, thus decreasing their concentrations. GSH biosynthesis is an important drug target.

Topics: Animals; Antimetabolites; Buthionine Sulfoximine; Cycloheximide; Glutathione; Nifurtimox; Nitroimidazoles; Species Specificity; Spermidine; Trypanocidal Agents; Trypanosoma cruzi

The carcinogenic activity of antitrypanosomal 2-nitroimidazole, 5-nitroimidazole and 5-nitrofuran derivatives was assessed in female Swiss mice of the same age group. A statistically significantly higher incidence of growths was seen in mice into which 2-nitro had been injected than in mice receiving 5-nitro derivatives intraperitoneally. A histologic type of lymphoblastic lymphoma that invades lymph nodes, spleen, liver, lungs and lymphatic tissue elsewhere was frequently found in nitroarene-treated mice. Further, it is shown that the potency of the drug, rather than the duration of its administration, was usually associated with the growth of lymphomas. The 2-nitro derivative which induced the highest incidence of lymphomas significantly decreased the survival of treated mice; this probably occurred because it undergoes enzymatic reduction of the nitro group more efficiently than the 5-nitro compounds used. The differences of incidence of lymphomas in mice receiving any of these nitroarenes and in control mice that received daily injections of 0.15 M saline were statistically significant (alpha = 0.05). The indiscriminate use of these nitroarenes to treat Trypanosoma cruzi infections in man could therefore induce a significant number of lymphomas.

Topics: Animals; Carcinogens; Cell Division; Chagas Disease; Female; Liver; Lymph Nodes; Lymphoma; Mice; Molecular Structure; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

With the exception of assays for the detection of antibodies promoting complement-mediated lysis of Trypanosoma cruzi, serologic tests have generally failed to assess the effectiveness of chemotherapy for Chagas' disease. Conventional serology, although useful for the diagnosis of infection, is not capable of determining which patients have been cured. Here we demonstrate that a high proportion of antibodies detected by conventional serology (using fixed epimastigotes or trypomastigotes or crude extracts obtained therefrom) are directed against the carbohydrate residue galactosyl alpha 1- > 3 galactose (Gal alpha 1- > 3 Gal), a determinant also recognized by antibodies from noninfected healthy volunteers. In a study of 14 cured patients with long-term followup, we found that the persistently positive reactions detected using conventional serology were largely eliminated following immunoadsorption with melibiose. Because of their wide distribution among microorganisms of intestinal and pulmonary microflora, these carbohydrate determinants may keep stimulating lymphocytes previously primed by T. cruzi Gal alpha 1- > 3 Gal epitopes, thereby accounting for false-positive results in cured patients. Consistent with this proposition, enzyme-linked immunosorbent assays performed with two distinct T. cruzi antigen preparations that lack the Gal alpha 1- > 3 Gal epitope, namely purified GP57/51 and trypomastigote-shed antigens, were indeed capable of determining a cure after chemotherapy, albeit to a different degree. Collectively, the data indicate that conventional immunoassays prepared with highly specific T. cruzi antigens can be useful in the assessment of a cure after chemotherapy.

Topics: Acute Disease; Adsorption; Adult; Animals; Antibodies, Protozoan; Antibody Specificity; Antigens, Protozoan; Chagas Disease; Child; Chronic Disease; Cross Reactions; Cysteine Endopeptidases; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Follow-Up Studies; Glycoproteins; Humans; Middle Aged; Nifurtimox; Nitroimidazoles; Treatment Outcome; Trypanocidal Agents; Trypanosoma cruzi

In rats infected with Trypanosoma lewisi, parasitaemia normally resolves by day 32; thereafter, the rodents become solidly immune to re-infection. Rats treated on day 5 of infection with a single i.m. dose of 35 mg/kg of the trypanocidal drug ethidium bromide (EB) had recovered from parasitaemia by day 12, whereas berenil (BE) given at 100 mg/kg, more than twice the recommended dose, had no effect on parasitaemia. However, rats treated for 4 consecutive days beginning on day 5 of infection with Lampit (LA) and Radanil (RA) at 350 mg/kg showed no parasitaemia on days 16 and 20, respectively. EB was the most effective drug in lowering the total IgG antibody as compared with the control animals, whose specific IgG titres remained elevated for over 200 days after the parasitaemia had been cleared. LA also significantly reduced the antibody levels through day 240, whereas RA only transitorily depressed the antibody levels on days 20 and 30. BE, which had no effect on parasitaemia, correspondingly failed to depress the total IgG levels. Re-challenge infection of the drug-treated, recovered animals on day 240 (208 days after the normal resolution of the infection) revealed that except for the EB group, which displayed transitory parasitaemia for 4 days, other treated and control rats completely resisted the challenge; pre-challenge antibody titres were lower than 1:160 in EB-treated animals in contrast to the levels of 1:320 or higher measured in the other drug-treated and control animals, which resisted the infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Antibodies, Protozoan; Diminazene; Ethidium; Female; Immunoglobulin G; Nifurtimox; Nitroimidazoles; Rats; Rats, Inbred F344; Trypanocidal Agents; Trypanosoma lewisi; Trypanosomiasis

Mice infected with Trypanosoma cruzi, but parasitologically cured after specific chemotherapy, continued to exhibit positive indirect immunofluorescence serological tests 3-6 months after the therapy. Treatment of trypanosome antigens with monospecific antisera produced in rabbits, and examination by immunoelectron-microscopy following peroxidase labelling disclosed the presence of membrane deposits in cell processes in the spleens of the mice. Similar deposits were observed in the external membranes of T. cruzi amastigotes in the spleens of acutely infected mice, but not in normal control mice. No reaction occurred in tissues not previously treated with the monospecific anti-T. cruzi serum. Positive cells in treated and cured mice, as well as in the not cured or untreated control mice, were located in germinal centres of the splenic white pulp and presented long and branching cytoplasmic processes, which are indicative of dendritic cells of the lymphoid follicles of the spleen.

Topics: Animals; Antigens, Protozoan; Chagas Disease; Mice; Microscopy, Immunoelectron; Nifurtimox; Nitroimidazoles; Spleen; Trypanocidal Agents

No studies exist on sister-chromatid exchange (SCE) formation in chagasic patients therapeutically exposed to nifurtimox (NFX) or benznidazol (BZ). In the present study SCE was analyzed in cultures of peripheral lymphocytes of patients aged 11 months to 11 years treated with NFX 12-15 mg/kg/d for 60 days or with BZ 5 mg/kg/d for 30 days. Chagasic patients before treatment constituted a control group. A mean of 30 metaphases were examined for each individual. All treated patients compared with untreated controls did not show a significant increase in SCE frequency. Compared with the percentage of chromosomal aberrations in these patients and others belonging to the same epidemic protocol, SCE seems to be less sensitive in the detection of lymphocyte chromosomal damage caused by NFX or BZ.

Topics: Chagas Disease; Child; Child, Preschool; Chromosomes; Dose-Response Relationship, Drug; Female; Humans; Lymphocytes; Male; Nifurtimox; Nitroimidazoles; Sister Chromatid Exchange; Trypanocidal Agents

Topics: Animals; Chagas Cardiomyopathy; Chagas Disease; Nifurtimox; Nitroimidazoles; Rabbits; Trypanocidal Agents

Use of 2-nitroimidazole, 5-nitrofuran and 5-nitroimidazole compounds in T. cruzi-infected rabbits resulted in a reduction in duration of parasitaemia in comparison with untreated, infected rabbits. The chronic myocarditis associated with Chagas' disease was not, however, prevented in nitroarene-treated rabbits; lymphocytic infiltrates associated with cardiac cell lysis, in the absence of parasites in situ, were present in both treated and untreated rabbits. The carcinogenic effect of each trypanocidal nitroarene used in this study was also assessed. Administration of nitroarenes to rabbits resulted in the appearance of solid tumours in 37.8 per cent of animals that received drug therapy. Untreated, control rabbits in this series did not show tumour growth. Furthermore, malignant, mixed-cell type, non-Hodgkin's lymphomas were seen in 32.4 per cent of the treated rabbits. It seems that a direct relationship could be present between the presence of the nitro group, the trypanocidal cytotoxicity and the prevalence of tumours. Benznidazole cleared up parasitaemias in the shortest time and was associated with 41.6 per cent of lymphoma growths, whereas MK-436 required twice as much time to clear blood parasites, and showed lymphomas in 25 per cent of experimental rabbits. The demonstration of a high prevalence of malignant tumours in addition to the chronic myocarditis of Chagas' disease in nitroarene-treated rabbits is important since indiscriminate use of such compounds currently used to treat T. cruzi infections in man could increase the risk of lymphoma.

Topics: Animals; Chagas Cardiomyopathy; Female; Injections, Intraperitoneal; Lymphoma, Non-Hodgkin; Male; Myocarditis; Myositis; Nifurtimox; Nitrofurans; Nitroimidazoles; Rabbits; Trypanosoma cruzi

The bioreductive activation of megazol [2-amino-5(1-methyl-5-nitro-2-imidazolyl)-1,3,4-thiadiazole] promoted by ferredoxin: NADP+ oxidoreductase, rat liver microsomes and cellular fractions of Trypanosoma cruzi, Y strain, was investigated. Direct ESR detection and characterization by computer simulation of the megazol nitro anion radical were possible in the presence of NADPH and ferredoxin: NADP+ oxidoreductase under anaerobic conditions. By contrast, the megazol nitro anion radical was not detected in the presence of either rat liver microsomes or cellular fractions of T. cruzi under conditions where the corresponding nifurtimox anion radical was observed. The inefficiency of rat liver microsomes in catalyzing megazol reduction was also attested by visible light absorption spectroscopy. In the presence of cellular fractions of T. cruzi supplemented with NAD(P)H, megazol marginally affected oxygen consumption and decreased the yield of oxyradicals that can be spin-trapped with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). Our results indicate a restricted bioreductive metabolism of megazol and suggest that its trypanocidal activity is unrelated to a redox-cycling process.

Topics: Animals; Chagas Disease; Ferredoxins; Microsomes, Liver; Mitochondria; Nifurtimox; Nitrofurans; Nitroimidazoles; Oxidation-Reduction; Oxygen Consumption; Rats; Subcellular Fractions; Thiadiazoles; Trypanosoma cruzi

After observing a fatal chagasic infection in a renal transplant recipient we investigated Chagas disease in 84 recipients of renal transplants. The indirect hemagglutination test was used for screening and xenodiagnosis followed in positive cases, along with ECG and gastrointestinal X ray series. Nine cases were detected (10%); parasites were found in the blood of 6 of them (66%). No patient had cardiac or gastrointestinal involvement. Patients with a positive serology were treated with nifurtimox (2) or benzonidazol (7); xenodiagnosis every 6 months up to 67 months remains negative in these patients. Blood transfusions are suspected as the mechanism for infection in these cases.

Topics: Adolescent; Adult; Chagas Disease; Female; Humans; Immune Tolerance; Kidney Transplantation; Male; Nifurtimox; Nitroimidazoles; Serologic Tests; Transfusion Reaction; Trypanocidal Agents

1. Glutathione (G-SH) concentration, gamma-glutamyltranspeptidase and glutathione S-transferase activities were studied in several strains of T. cruzi epimastigotes. GSH varied from 1.04 mM for the LQ strain to 0.61 mM for the Tulahuen strain. 2. Cultures of the LQ strain presented more resistance to drugs than those of the Tulahuen. It was necessary a concentration of nifurtimox 4 times higher and one of benznidazole 10 times higher in order to inhibit approximately to 50% the growth of LQ strain cultures when compared with the Tulahuen strain. 3. Buthionine sulfoximine decreased the concentration of glutathione to about 50% in the LQ and Tulahuen strains and potentiated the toxicity of nifurtimox and benznidazole in T. cruzi epimastigote cultures. These results suggest that glutathione is an important factor in the resistance of T. cruzi to nifurtimox and benznidazole.

Topics: Animals; Antimetabolites; Buthionine Sulfoximine; Diazooxonorleucine; gamma-Glutamyltransferase; Glutathione; Glutathione Transferase; Methionine Sulfoximine; Nifurtimox; Nitrofurans; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Nifurtimox (NF) and benznidazole (BZ), drugs used in the treatment of Chagas' disease, did not inhibit protein biosynthesis in in vitro homologous cell-free systems isolated from Trypanosoma cruzi and Crithidia fasciculata; nevertheless, their addition to growing cultures caused polyribosomal depolymerization. On the other hand, Berenil, Antrycide and suramin, used against African trypanosomiasis, inhibited protein biosynthesis in vitro but did not affect ribosomal distribution, probably due to low permeability to the drugs. The results suggest that the inhibition by NF and BZ of protein synthesis, measured as [14C]leucine incorporation by other authors, is indirect, probably through inhibition of nucleic acid synthesis and energy metabolism.

Topics: Animals; Crithidia; In Vitro Techniques; Nifurtimox; Nitrofurans; Nitroimidazoles; Protein Biosynthesis; Trypanocidal Agents; Trypanosoma cruzi

Chagas' disease is a parasitic chronic condition affecting several million people in Latin America. Two drugs are used in the chemotherapy of Chagas' disease: nifurtimox (Nfx) and benznidazole (Bz). Both are nitroderivatives whose deleterious effects are related to their reductive biotransformation. In this work we report that rat ovaries exhibited Bz and Nfx nitroreductase activity. The Bz nitroreductase was only found in the mitochondrial fraction and was partially inhibited by CO. The Nfx nitroreductase activity was maximal in ovarian mitochondria but was also present in microsomes and in the cytosol. The microsomal enzyme was completely inhibited by CO while that in mitochondria was only partially inhibited by CO. The cytosolic activity only proceeded using hypoxanthine as substrate and was inhibited by allopurinol. The cytosolic activity was able to proceed in part under oxygen. All the other Bz or Nfx nitroreductases were completely inhibited by atmospheric oxygen. The potential participation of cytochrome P450, flavoenzymes, iron-sulfur-protein, and xanthinooxidase in both nitroreductive processes is discussed. The administration of either Nfx or Bz to female rats produced ultrastructural degenerative effects in the different cell types of ovaries. Specific alterations such as swelling, disruption, disorganization, and loss of matrix components were observed in ovarian mitochondria. These alterations occurred irrespectively of the ovarian cycle stage. The potential reproductive toxicological consequences of Bz or Nfx administration are analyzed.

Topics: Animals; Biotransformation; Cytosol; Female; Microscopy, Electron; Microsomes; Mitochondria; Nifurtimox; Nitrofurans; Nitroimidazoles; Nitroreductases; Ovary; Oxidoreductases; Rats; Rats, Inbred Strains; Trypanocidal Agents

Both nifurtimox and benznidazole, which are used for the treatment of Chagas' disease, also display marked antibacterial activities. Characteristically for nitroheterocyclic compounds, they are much more active against anaerobic and microaerophilic bacteria than against aerobic bacteria. Nitroreductase-deficient aerobes are completely resistant, whereas SOS-repair-deficient strains are moderately susceptible. Those strains are rapidly killed.

Topics: Bacteria; Bacteria, Aerobic; Bacteria, Anaerobic; Microbial Sensitivity Tests; Nifurtimox; Nitrofurans; Nitroimidazoles; Trypanocidal Agents

Topics: Animals; DNA; Liver; Male; Nifurtimox; Nitrofurans; Nitroimidazoles; Protein Biosynthesis; Rats; Rats, Inbred Strains

1. Addition of nifurtimox or benznidazole to the NADH-containing mitochondrial fraction of Crithidia fasciculata led to the appearance of the characteristic ESR spectra corresponding to their nitro anion radicals, suggesting that the nitro anion radical is a necessary intermediate in the reduction of both nitro compounds. 2. Nifurtimox anion radical generation by the mitochondrial fraction was insensitive to rotenone and antimycin A but was enhanced by KCN. 3. The nifurtimox anion radical reacted with oxygen under aerobic conditions leading to an increase in the cyanide-insensitive respiration of the intact cells and in the rate of O2- and H2O2 production by the C. fasciculata mitochondrial fraction. 4. In contrast, generation of O2- and H2O2 was not stimulated with pharmacological concentrations of benznidazole. Furthermore, benznidazole inhibited the cyanide-insensitive respiration of the intact cells.

Topics: Animals; Crithidia; Free Radicals; Mitochondria; Nifurtimox; Nitrofurans; Nitroimidazoles; Oxidation-Reduction; Trypanocidal Agents; Trypanosoma cruzi

A comparative study showed that 5 laboratory strains of Trypanosoma cruzi could be divided into a non-responsive group (Sonya clone and Colombiana) and a responsive group (Tulahuén, Y and Peru), based on long-term treatment of mouse infections with nifurtimox and benznidazole. In vitro sensitivity of epimastigotes and blood-stream trypomastigotes in macrophage cultures did not distinguish the strains, nor did the rate of development of nifurtimox resistance by epimastigote cultures. 7 novel anti-T. cruzi compounds also behaved similarly with respect to the 2 groups. A small decrease in sensitivity was observed in vitro by non-responsive strains of T. cruzi after re-isolation from treated mice. It is postulated that there could be an immunological component involved in successful treatment of T. cruzi infection.

Topics: Animals; Dose-Response Relationship, Drug; Drug Resistance; Macrophages; Male; Mice; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi; Trypanosomiasis

Topics: Adolescent; Chagas Disease; Child; Child, Preschool; Chromosome Banding; Chromosome Fragility; Humans; Infant; Metaphase; Micronucleus Tests; Nifurtimox; Nitrofurans; Nitroimidazoles; Trypanocidal Agents

1. The mutagenicity of serum and urine from guinea pigs treated with a single oral dose (500 mg/kg) of benznidazole and nifurtimox was assayed using the Salmonella/plate incorporation test with strain TA 100 and a nitroreductase-deficient derivative, TA 100NR. 2. The urine and blood of animals treated with nifurtimox were not mutagenic for either tester strain. 3. The urine and blood of animals receiving benznidazole were mutagenic to the TA 100 but not to the TA 100NR strain. Similar results were obtained with nitrofurantoin-treated animals. Maximum mutagenicity values were obtained in serum and urine of treated animals 90 min and 24 h after administration, respectively. 4. Mutagenicity induced by benznidazole in the serum and urine of treated animals was not altered when assayed in anaerobic environments. 5. These results indicate that benznidazole and nifurtimox are not metabolized by the mammalian host into stable mutagenic derivatives detectable by the Ames test. Based on these data, we suggest that the potential cancer risk to patients treated with these drugs is small but should be further evaluated.

Topics: Animals; Female; Guinea Pigs; Male; Mutagenicity Tests; Mutation; Nifurtimox; Nitrofurans; Nitrofurantoin; Nitroimidazoles

Salmonella typhimurium TA100 and its nitroreductase-deficient derivative, TA100 NR, were used to reevaluate the mutagenic activities of benznidazole and nifurtimox. Mutagenicity and toxicity of nifurtimox were abolished in the TA100 NR tester strain under aerobic or anaerobic conditions and addition of rat liver extracts did not alter the results. However, benznidazole showed a significant mutagenicity and toxicity to the nitroreductase-deficient strain TA100 NR under hypoxic conditions. Addition of rat liver extracts enhanced the observed mutagenicity and toxicity of benznidazole even more. In the presence of O2 the genotoxic activities of benznidazole to the TA100 NR tester strain were eliminated. These results lead us to conclude that bacterial enzymes were responsible for the previously observed genotoxic effects of nifurtimox and benznidazole on S. typhimurium TA100. Moreover, under anaerobic conditions, only benznidazole could be metabolized by mammalian nitroreductases into a mutagenic derivative.

Topics: Animals; Biotransformation; Microsomes, Liver; Mutagenicity Tests; Mutagens; Nifurtimox; Nitrofurans; Nitroimidazoles; Nitroreductases; Rats; Salmonella typhimurium; Trypanosoma cruzi

The susceptibility and natural resistance to two nitroheterocyclic derivatives used clinically in Chagas disease (nifurtimox and benznidazole) were investigated in 47 Trypanosoma cruzi strains isolated from human patients, domestic vectors and sylvatic reservoirs or vectors. A large gradient of drug efficacy from 0% to 100% was detected. Drug susceptibility apparently related to geographical distribution of some T. cruzi strains was also observed. Drug resistance was identified among T. cruzi populations isolated from sylvatic vectors from an area where autochthonous human Chagas disease does not exist. Thus, natural drug-resistance of sylvatic strains might be a way of introducing this character into a T. cruzi domestic cycle. Most of the 47 studied strains were either sensitive or resistant to both compounds, an intriguing finding considering that nifurtimox and benznidazole apparently have different mechanisms of action against T. cruzi.

Topics: Animals; Chagas Disease; Drug Resistance; Male; Mice; Nifurtimox; Nitrofurans; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Nifurtimox (Nfx) and Benznidazole (Bz) are 2 drugs used in the chemotherapy of Chagas' disease, a sickness afflicting millions of Latin Americans. Their toxicity is related to nitroreductive activation. Nfx and Bz nitroreductase activity in liver microsomes from male rats is already present at low levels in the newborn and reaches full adult activity in 28 days. This suggests a better therapeutic approach by starting the treatment of transplacentally acquired Chagas' disease immediately after birth.

Topics: Aging; Animals; Cytochrome P-450 Enzyme System; Male; Microsomes, Liver; Nifurtimox; Nitrofurans; Nitroimidazoles; Nitroreductases; Rats; Rats, Inbred Strains; Trypanocidal Agents

Topics: Drug Resistance, Microbial; Escherichia coli; Lysogeny; Mutagenicity Tests; Mutation; Nifurtimox; Nitrofurans; Nitroimidazoles; Salmonella typhimurium; SOS Response, Genetics; Trypanocidal Agents

The induction of sister-chromatid exchange (SCE) was analyzed in spleenic lymphocytes of mouse after exposure to nifurtimox (NFX) or benznidazole (BZ). Lymphocytes from Swiss mice treated "in vivo" with 1200 and 2000 mg/kg NFX (p.o.) and then incubated "in vitro" with bromo-2'-deoxyuridine showed an increased frequency of SCE. No significant differences were observed in mice treated with 2000 mg/kg BZ (p.o.). The present and previous results obtained in this and other laboratories suggest that the effects observed should warn against the potential risk of NFX treatment in humans receiving this chemotherapeutic agent as a treatment for Chagas' disease.

Topics: Animals; Lymphocytes; Male; Mice; Mutagenicity Tests; Nifurtimox; Nitrofurans; Nitroimidazoles; Sister Chromatid Exchange; Spleen

Nifurtimox (NFX) and Benznidazole (Bz) are two drugs effective against acute Chagas' disease. Both have considerable toxic side effects related to nitroreductive biotransformation. In this work, we studied the species and sex differences in liver microsomal NFX (NFX-ase) and Bz nitroreductase activity (Bz-ase). Animal species tested were rats, mice, hamsters and guinea-pigs. Bz-ase is significantly higher in male rats and hamsters than in females. No significant sex difference was observed in mice or guinea-pigs. Bz-ase in the males is: hamsters greater than mice greater than guinea-pig approximately equal to rat and in females it is: mice approximately equal to guinea-pig approximately equal to hamster greater than rat. NFX-ase is higher in either male rats or female mice than in either female rats or male mice. No sex difference was observed in the other species. In males NFX-ase is: hamsters approximately equal to mice greater than rat approximately equal to guinea-pig, while in females it is mice approximately equal to hamsters greater than guinea-pig approximately equal to rat. Results suggest that hamsters and mice might be the most suitable species to study toxic effects related to their liver microsomal nitroreductive biotransformation. This might be of particular relevance for carcinogenicity studies.

Topics: Animals; Biotransformation; Cricetinae; Female; Guinea Pigs; In Vitro Techniques; Male; Mesocricetus; Mice; Microsomes, Liver; Nifurtimox; Nitrofurans; Nitroimidazoles; Nitroreductases; Oxidation-Reduction; Oxidoreductases; Rats; Rats, Inbred Strains; Sex Factors; Species Specificity; Trypanocidal Agents

The genetic activities of two widely used anti-Trypanosoma cruzi drugs, nifurtimox and benznidazole, were investigated. The Salmonella mutagenicity (Ames) test was used to evaluate the mutagenic activity of both drugs. Nifurtimox and benznidazole preferentially induced backward mutations in the base substitution mutagen indicator strain TA100. The observed mutation rates for both drugs were linear over a wide concentration range. Maximum mutagenic activity was obtained at 35 and 100 micrograms per plate for nifurtimox and benznidazole, respectively. No increase in the mutagenic activity of either drug was observed in the presence of rat liver microsomal extracts. Survival experiments revealed that nifurtimox was at least four times more toxic than benznidazole for the Salmonella indicator strain.

Topics: Mutagenicity Tests; Mutagens; Nifurtimox; Nitrofurans; Nitroimidazoles; Salmonella typhimurium

Ultrastructural and biochemical alterations in testes of Sprague-Dawley rats receiving either nifurtimox (Nfx) or benznidazole (Bz) (both 100 mg/kg po) were studied. Nfx produced intense deleterious effects on Steroli cells consisting of dilatation of endoplasmic reticulum and perinuclear membrane, alterations in shape and size of mitochondria, increased lysosomal activity, detachment of ribosomes, and alterations in shape and configuration of spermatids and mature spermatozoa. Bz induced alterations were similar in nature but far less intense and observable only in some cells or preparations or animals but not in others. Testicular Nfx but not Bz nitroreductase activity was detected in microsomal and cytosolic fractions. Microsomal Nfx nitroreductase activity was not inhibited by CO. The cytosolic activity in the presence of hypoxanthine was inhibited by allopurinol and that in the presence of N-methylnicotinamide was inhibited by menadione. All these enzymatic activities were inhibitable by oxygen except the cytosolic one in the presence of N-methylnicotinamide. No evidence for lipid peroxidation was found in testes from Nfx treated animals. Covalent binding of Bz reductive metabolites to testicular proteins and phospholipids was found. Toxicological and pharmacological implications for patients suffering Chagas' disease and receiving these drugs were analyzed.

Topics: Animals; Biotransformation; Cytosol; Endoplasmic Reticulum; Lipid Peroxides; Male; Microscopy, Electron; Microsomes; Nifurtimox; Nitrofurans; Nitroimidazoles; Nitroreductases; Organoids; Phospholipids; Protein Binding; Rats; Rats, Inbred Strains; Sertoli Cells; Spermatozoa; Testis

Nifurtimox and benznidazole, two nitroheterocyclic drugs, inhibited DNA, RNA and protein synthesis, stimulated macromolecular degradation, and stimulated unscheduled DNA synthesis in Trypanosoma cruzi (Tulahuen strain). Significant differences in the mode of action of these drugs could be established and, in every case, nifurtimox was more active than benznidazole. The inhibition of macromolecular synthesis varied with drug concentration, precursor and incubation time. Nifurtimox effect was time dependent and irreversible. When assayed on macromolecular degradation, nifurtimox was more effective on DNA and protein than on RNA, while benznidazole displayed almost the same activity on DNA, RNA and protein. Labeling of RNA with [3H]uridine in the presence of nifurtimox followed atypical kinetics since, depending on incubation time and concentration, RNA degradation prevailed over RNA synthesis.

Topics: Animals; DNA; Leucine; Macromolecular Substances; Nifurtimox; Nitro Compounds; Nitroimidazoles; Protein Biosynthesis; Proteins; RNA; Thymidine; Trypanocidal Agents; Trypanosoma cruzi; Uridine

Liver microsomes from Sprague-Dawley male rats are able to biotransform Benznidazole (Bz) or Nifurtimox (NFX) by nitroreduction. Pretreatment of the rats during three days with phenobarbital (80 mg/kg/day, ip) but not with 3-methylcholanthrene (35 mg/kg/day ip) increased both Bz and NFX nitroreductase activity. Results suggest that cytochrome P-450 but not cytochrome P-448 is involved in the nitroreduction of these two chemotherapeutic agents against Chagas' disease. Possible pharmacological and toxicological implications of these observations are discussed.

Topics: Animals; Biotransformation; Male; Methylcholanthrene; Microsomes, Liver; Nifurtimox; Nitrofurans; Nitroimidazoles; Nitroreductases; Oxidation-Reduction; Oxidoreductases; Phenobarbital; Rats; Rats, Inbred Strains

Kinetoplast DNA (kDNA) from Trypanosoma cruzi epimastigotes pretreated with the trypanocidal drugs nifurtimox (10 or 100 microM) or benznidazole (38 or 380 microM) showed an increased number of strand-breaks, as revealed by (a) trapping of alkali-denatured kDNA by nitrocellulose filters and (b) electrophoresis in an alkaline 2% agarose gel. Similar damage was observed in nuclear DNA (nDNA), as detected by centrifugation in an alkaline-sucrose gradient. DNA damage was reversible since reincubation in fresh medium for 24 hr restored filtration and electrophoretic and sedimentation patterns to normal.

Topics: Animals; DNA; Nifurtimox; Nitrofurans; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

A test was made of the susceptibility of 30 strains of Trypanosoma cruzi to chemotherapy with nifurtimox (Bay 2502) and benznidazole (Ro 7-1051). The strains had previously been classified as type I, II, or III according to their morphobiological and isoenzymic characteristics. Three type I strains, 14 type II strains, and 13 type III strains were studied. Mice were infected with 2 x 10(5) blood forms of these parasites and treated for 90 days with benznidazole or nifurtimox. All the surviving mice were submitted to parasitological tests (direct parasitaemia, xenodiagnosis, inoculation in new-born mice, and haemoculture) and serological tests (indirect immunofluorescence). As the latter remained positive in about 80% of the parasitologically negative animals, the cure rates were based on the more reliable parasitological tests. Type I strains displayed high susceptibility, type II strains showed medium to high susceptibility, and type III strains were highly resistant to both drugs. The fact that a particular strain type, with its own level of susceptibility, usually predominates in a given geographical area may explain the contradictory results after chemotherapy from different endemic areas.

Topics: Animals; Chagas Disease; Mice; Nifurtimox; Nitrofurans; Nitroimidazoles; Species Specificity; Trypanocidal Agents

Sprague-Dawley male rats were treated with either 100 mg/kg Nifurtimox or Benznidazole p.o. and pentane evolution was measured at different periods of time. No significant increase in pentane evolution was observed in animals treated with Benznidazole during periods of time up to 10 h. In animals treated with Nifurtimox, a significant increase in pentane evolution was observed at 10 h but not at 3 or 6 h. The pentane evolution effect of Nifurtimox was compared to that of carbon tetrachloride. The latter was very intense up to 1 h and ceased thereafter. The possible participation of lipid peroxidation in the unwanted toxic side effects of Nifurtimox and Benznidazole is discussed.

Topics: Animals; Carbon Tetrachloride; Lipid Peroxides; Male; Nifurtimox; Nitrofurans; Nitroimidazoles; Pentanes; Rats; Rats, Inbred Strains; Trypanocidal Agents

A single nifurtimox administration to male mice orally (p.o.) (600 - 2000 mg/kg) but not intraperitoneally (i.p.) was able to increase micronucleus formation in bone marrow significantly. No significant increase in micronucleus formation in the bone marrow of mice treated with benznidazole at dosages up to 2000 mg/kg, either p.o. or i.p., was observed. The potential mutagenic risk of nifurtimox treatment in patients suffering from Chagas' disease is analyzed.

Topics: Animals; Bone Marrow; Cell Nucleus; Male; Mice; Mutagens; Nifurtimox; Nitrofurans; Nitroimidazoles; Trypanocidal Agents

Topics: Animals; DNA; Nifurtimox; Nitrofurans; Nitroimidazoles; Protein Biosynthesis; RNA; Trypanocidal Agents; Trypanosoma cruzi

Incubation of Trypanosoma cruzi culture (epimastigote) forms with nifurtimox (10 or 100 microM), benznidazole (38 or 380 microM) and beta-lapachone (1.6 or 7.8 microM) produced damage of nuclear DNA, as shown by the increased rate of the "unscheduled DNA synthesis" in epimastigotes arrested at phase S (9-, 3-, and 6-fold, respectively). alpha-lapachone, a position isomer of beta-lapachone, was completely ineffective. In order to demonstrate the "unscheduled repair of DNA", the semiconservative replication was inhibited by preincubating the epimastigotes for 16 hours with 10 mM hydroxyurea and 0.3 mM cycloheximide. Kinetoplast DNA (kDNA) extracted from epimastigotes pretreated with the trypanocidal agents revealed an increased number of single-strand breaks. After alkaline agarose-gel electrophoresis, a fast moving DNA fraction was detected in the kDNA from nifurtimox, benznidazole and beta-lapachone-treated parasites, while trapping of alkali-denatured kDNA by nitrocellulose filters, was significantly increased after treating the epimastigotes with the same drugs. Reincubation of these epimastigotes in fresh medium for 24 h, reestablished kDNA electrophoretic and filtration patterns to normality, except with 7.8 microM beta-lapachone, thus proving the reversibility of DNA lesions. Redox-cycling of nifurtimox and beta-lapachone in T. cruzi generates oxygen radicals, and accordingly, the higher effectiveness of these drugs (as compared with benznidazole and alpha-lapachone) supports the role of oxygen radicals for the trypanocidal action.

Topics: Animals; DNA; DNA Damage; DNA Repair; Free Radicals; Naphthoquinones; Nifurtimox; Nitroimidazoles; Oxidation-Reduction; Trypanocidal Agents; Trypanosoma cruzi

Incubation of rat liver cell-free extracts with an NADPH-generating system and with nifurtimox or benznidazole (two nitroheterocyclic drugs used in the treatment of Chagas' disease) produced oxidation of reduced glutathione (GSH) and increased lipid peroxidation, as shown by the generation of thiobarbituric-acid-reacting intermediates. Nifurtimox and benznidazole inhibited GSSG-reductase, but not GSH-peroxidase, the former inhibition contributing to GSH depletion. In every case, nifurtimox was more effective than benznidazole. Addition of GSH or free-radical scavengers (catalase, superoxide dismutase, mannitol, sodium benzoate or L-histidine) prevented the effect of nifurtimox on lipid peroxidation reactions. These results support the assumption [M. Dubin, S. N. J. Moreno, E. E. Martino, R. Docampo and A. O. M. Dubin, Biochem. Pharmac. 32, 483 (1983)] that, in the rat liver, GSH exerts a protective action against oxygen radicals generated by the nitroheterocyclic drugs.

Topics: Animals; Free Radicals; Glutathione; In Vitro Techniques; Lipid Peroxides; Liver; Male; Malondialdehyde; Nifurtimox; Nitrofurans; Nitroimidazoles; Rats; Rats, Inbred Strains; Tissue Extracts; Trypanocidal Agents

Nifurtimox and benznidazole have trypanostatic actions in vitro and inhibit the incorporation of [3H] thymidine, [3H] uridine and L-[3H] leucine in T. cruzi macromolecules. The effect of nifurtimox may be explained by (a) direct inhibition of nucleic acid biosynthesis, or (b) generation of the oxygen radicals in T. cruzi and therefore, only mechanism (a) should be valid. In order to obtain more information on the action of these drugs on T. cruzi, in the present study we examined the effect of nifurtimox and benznidazole on DNA, RNA and protein turnover in epimastigote (culture) forms of the parasite. Complementary experiments were performed with beta-lapachone that, like nifurtimox, generates oxygen radicals in T. cruzi. Epimastigotes (Tulahuen strain) at the exponential-phase of growth were cultured with [3H] thymidine, [3H] uridine or L-[3H] leucine to label DNA, RNA and protein, respectively. After incubation, the cells were washed free of radioactive precursor, resuspended in fresh medium and reincubated at 30 degrees C with nifurtimox (10 or 100 microM), benznidazole (38 or 380 microM) or beta-lapachone (1.6 or 7.8 microM), for 1-3 hours. Controls were incubated without drug. At one hour time intervals, sampler were taken, washed free of medium and filtered through 0.45 microns Metricel filters. The filters were washed with 10% trichloroacetic acid to remove the acid soluble material, and after drying, the radioactivity incorporated in DNA, RNA and protein was counted with a scintillation counter. The results show that after elimination of the labelled precursors, 3H activity in DNA, RNA and protein decayed as a function of the time of incubation. Nifurtimox, benznidazole and beta-lapachone, stimulated in all cases they decay of the incorporated radioactivity. Calculation of "half-life" values for DNA, RNA and protein(s) indicated that nifurtimox and beta-lapachone exerted their greatest effects on DNA while benznidazole increased the decay of DNA, RNA and protein to about the same extent. Taking into account the effects of nifurtimox and beta-lapachone on DNA stability, specific lesions (single-strand breaks) were investigated in DNA from control, nifurtimox, benznidazole or beta-lapachone treated epimastigotes. The number of single-strand breaks was (per 10(6)b) 25 with 100 microM nifurtimox, 1.4 with 380 microM benznidazole and 45 with 7.8 microM g-lapachone. Interestingly enough, after reincubation of nifurtimox-damaged epimastigotes in fresh me

Topics: Animals; Depression, Chemical; DNA; DNA Damage; Free Radicals; Naphthoquinones; Nifurtimox; Nitrofurans; Nitroimidazoles; Oxygen; Protein Biosynthesis; RNA; Trypanocidal Agents; Trypanosoma cruzi

Topics: Animals; Hydrogen Peroxide; In Vitro Techniques; Microsomes, Liver; NADP; Nifurtimox; Nitrofurans; Nitroimidazoles; Oxygen Consumption; Rats; Superoxides; Trypanosoma cruzi

Topics: Animals; Chagas Cardiomyopathy; Chagas Disease; Female; Intestinal Diseases, Parasitic; Mice; Mice, Inbred Strains; Myositis; Nifurtimox; Nitroimidazoles; Trypanocidal Agents

Rat and human feces are able to reduce nitro group from Benznidazole (N-benzyl-2-nitro-1-imidazole acetamide) and Nifurtimox (4[5-nitrofurfurylidene)-amino)-3-methylthiomorpholine-1,1-dioxide), two chemotherapeutic agents against Chagas' disease. Feces from rats treated with neomycin sulfate lack nitroreductase activity evidencing the bacterial origin of the enzyme.

Topics: Animals; Feces; Humans; Male; Neomycin; Nifurtimox; Nitro Compounds; Nitrofurans; Nitroimidazoles; Nitroreductases; Oxidation-Reduction; Oxidoreductases; Rats; Rats, Inbred Strains; Species Specificity

The biological properties of a novel compound 353C with high activity against Trypanosoma cruzi, are described. The compound was about 10 times and 20 times more effective than either benznidazole or nifurtimox respectively, in producing radical cure in mice. 353C has a long half-life and showed anti-trypanosomal properties when given to mice at weekly intervals.

Topics: Animals; Biphenyl Compounds; Chagas Disease; Drug Evaluation, Preclinical; Mice; Nifurtimox; Nitroimidazoles; Trypanocidal Agents; Trypanosoma cruzi

Topics: Animals; Chagas Disease; Humans; Mice; Nifurtimox; Nitrofurans; Nitrofurazone; Nitroimidazoles; Trypanosoma cruzi

Topics: Humans; Nifurtimox; Nitrofurans; Nitroimidazoles

Topics: Amphotericin B; Animals; Chagas Disease; Drug Evaluation, Preclinical; Mice; Nifurtimox; Nitroimidazoles; Trypanocidal Agents