Chagas Cardiomyopathy in Latin America Review

New insights into Trypanosoma cruzi genetic diversity, and its influence on parasite biology and clinical outcomes

Chagas disease, caused by Trypanosoma cruzi, remains a serious public health problem worldwide. The parasite was subdivided into six distinct genetic groups, called "discrete typing units" (DTUs), from TcI to TcVI. Several studies have indicated that the heterogeneity of T. cruzi species directly affects the diversity of clinical manifestations of Chagas disease, control, diagnosis performance, and susceptibility to treatment. Thus, this review aims to describe how T. cruzi genetic diversity influences the biology of the parasite and/or clinical parameters in humans. Regarding the geographic dispersion of T. cruzi, evident differences were observed in the distribution of DTUs in distinct areas. For example, TcII is the main DTU detected in Brazilian patients from the central and southeastern regions, where there are also registers of TcVI as a secondary T. cruzi DTU. An important aspect observed in previous studies is that the genetic variability of T. cruzi can impact parasite infectivity, reproduction, and differentiation in the vectors. It has been proposed that T. cruzi DTU influences the host immune response and affects disease progression. Genetic aspects of the parasite play an important role in determining which host tissues will be infected, thus heavily influencing Chagas disease's pathogenesis. Several teams have investigated the correlation between T. cruzi DTU and the reactivation of Chagas disease. In agreement with these data, it is reasonable to suppose that the immunological condition of the patient, whether or not associated with the reactivation of the T. cruzi infection and the parasite strain, may have an important role in the pathogenesis of Chagas disease. In this context, understanding the genetics of T. cruzi and its biological and clinical implications will provide new knowledge that may contribute to additional strategies in the diagnosis and clinical outcome follow-up of patients with Chagas disease, in addition to the reactivation of immunocompromised patients infected with T. cruzi.

The importance of estimating the burden of disease from foodborne transmission of Trypanosoma cruzi

Chagas disease (ChD), caused by infection with the flagellated protozoan, Trypanosoma cruzi, has a complicated transmission cycle with many infection routes. These include vector-borne (via the triatomine (reduviid bug) vector defecating into a skin abrasion, usually following a blood meal), transplacental transmission, blood transfusion, organ transplant, laboratory accident, and foodborne transmission. Foodborne transmission may occur due to ingestion of meat or blood from infected animals or from ingestion of other foods (often fruit juice) contaminated by infected vectors or secretions from reservoir hosts. Despite the high disease burden associated with ChD, it was omitted from the original World Health Organization estimates of foodborne disease burden that were published in 2015. As these estimates are currently being updated, this review presents arguments for including ChD in new estimates of the global burden of foodborne disease. Preliminary calculations suggest a burden of at least 137,000 Disability Adjusted Life Years, but this does not take into account the greater symptom severity associated with foodborne transmission. Thus, we also provide information regarding the greater health burden in endemic areas associated with foodborne infection compared with vector-borne infection, with higher mortality and more severe symptoms. We therefore suggest that it is insufficient to use source attribution alone to determine the foodborne proportion of current burden estimates, as this may underestimate the higher disability and mortality associated with the foodborne infection route.

Persistent Biofluid Small-Molecule Alterations Induced by Trypanosoma cruzi Infection Are Not Restored by Parasite Elimination

Chagas disease (CD), caused by Trypanosoma cruzi (T. cruzi) protozoa, is a complicated parasitic illness with inadequate medical measures for diagnosing infection and monitoring treatment success. To address this gap, we analyzed changes in the metabolome of T. cruzi-infected mice via liquid chromatography tandem mass spectrometry of clinically accessible biofluids: saliva, urine, and plasma. Urine was the most indicative of infection status across mouse and parasite genotypes. Metabolites perturbed by infection in urine include kynurenate, acylcarnitines, and threonylcarbamoyladenosine. Based on these results, we sought to implement urine as a tool for the assessment of CD treatment success. Strikingly, it was found that mice with parasite clearance following benznidazole antiparasitic treatment had an overall urine metabolome comparable to that of mice that failed to clear parasites. These results provide a complementary hypothesis to explain clinical trial data in which benznidazole treatment did not improve patient outcomes in late-stage disease, even in patients with successful parasite clearance. Overall, this study provides insights into new small-molecule-based CD diagnostic methods and a new approach to assess functional responses to treatment.

Acute Myopericarditis Secondary to Chagas Disease

American trypanosomiasis or Chagas disease is predominantly a vector-borne multisystemic infection caused by Trypanosoma cruzi, a protozoan parasite transmitted by triatomine bugs in endemic areas such as Mexico and Central and South America. Acute T. cruzi infection is mostly asymptomatic, nonetheless, in up to one-third of the patients, a mild form of the disease can be present, with nonspecific manifestations like fever, lymphadenopathy, hepatosplenomegaly, inflammation at the inoculation site (inoculation chancre) and unilateral palpebral edema (Romaña sign). Severe acute disease occurs in less than 1% of patients and includes myopericarditis and meningoencephalitis. If untreated, the acute phase can cause chronicity with cardiac and gastrointestinal involvement. We report the case of a female with occupational exposure to this parasite, who presented with acute myopericarditis, a rare form of presentation of this disease.

Persistent biofluid small molecule alterations induced by Trypanosoma cruzi infection are not restored by antiparasitic treatment

Chagas Disease (CD), caused by Trypanosoma cruzi (T. cruzi) protozoa, is a complicated parasitic illness with inadequate medical measures for diagnosing infection and monitoring treatment success. To address this gap, we analyzed changes in the metabolome of T. cruzi-infected mice via liquid chromatography tandem mass spectrometry analysis of clinically-accessible biofluids: saliva, urine, and plasma. Urine was the most indicative of infection status, across mouse and parasite genotypes. Metabolites perturbed by infection in the urine include kynurenate, acylcarnitines, and threonylcarbamoyladenosine. Based on these results, we sought to implement urine as a tool for assessment of CD treatment success. Strikingly, it was found that mice with parasite clearance following benznidazole antiparasitic treatment had comparable overall urine metabolome to mice that failed to clear parasites. These results match with clinical trial data in which benznidazole treatment did not improve patient outcomes in late-stage disease. Overall, this study provides insights into new small molecule-based CD diagnostic methods and a new approach to assess functional treatment response.

Trypanosoma cruzi Infection Promotes Vascular Remodeling and Coexpression of α-Smooth Muscle Actin and Macrophage Markers in Cells of the Aorta

Chagas disease is an emerging global health problem; however, it remains neglected. Increased aortic stiffness (IAS), a predictor of cardiovascular events, has recently been reported in asymptomatic chronic Chagas patients. After vascular injury, smooth muscle cells (SMCs) can undergo alterations associated with phenotypic switch and transdifferentiation, promoting vascular remodeling and IAS. By studying different mouse aortic segments, we tested the hypothesis that Trypanosoma cruzi infection promotes vascular remodeling. Interestingly, the thoracic aorta was the most affected by the infection. Decreased expression of SMC markers and increased expression of proliferative markers were observed in the arteries of acutely infected mice. In acutely and chronically infected mice, we observed cells coexpressing SMC and macrophage (Mo) markers in the media and adventitia layers of the aorta, indicating that T. cruzi might induce cellular processes associated with SMC transdifferentiation into Mo-like cells or vice versa. In the adventitia, the Mo cell functional polarization was associated with an M2-like CD206+arginase-1+ phenotype despite the T. cruzi presence in the tissue. Only Mo-like cells in inflammatory foci were CD206+iNOS+. In addition to the disorganization of elastic fibers, we found thickening of the aortic layers during the acute and chronic phases of the disease. Our findings indicate that T. cruzi infection induces a vascular remodeling with SMC dedifferentiation and increased cell populations coexpressing α-SMA and Mo markers that could be associated with IAS promotion. These data highlight the importance of studying large vessel homeostasis in Chagas disease.

Long-term Survival Following Heart Transplantation for Chagas Versus Non-Chagas Cardiomyopathy: A Single-center Experience in Northeastern Brazil Over 2 Decades

Data on post–heart transplant (HT) survival of patients with Chagas cardiomyopathy (CC) are scarce. We sought to evaluate post-HT survival in patients with CC as compared with other causes of heart failure across different eras of HT.

Tailored management of life-threatening complications related to severe obesity in a young adult with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is characterized by hypotonia, distinctive facial features, hyperphagia, obesity, short stature, hypogonadism, intellectual disability, and behavior problems. Uncontrolled hyperphagia can lead to dangerous food-seeking behavior and with life-threatening obesity. Severe obesity is prone to obstructive sleep apnea (OSA) and can lead to cor pulmonale. This study reports on a case involving a 21-year-old man with PWS who developed OSA due to severe obesity, which led to cor pulmonale, a life-threatening complication. Multidisciplinary care provided in the intensive care unit included weight reduction, ventilation support, antipsychotics, sedative drugs, rehabilitation, and meticulous skin care. The patient did recover. To prevent severe obesity in adults with PWS, hyperphagia must be controlled, and the patient must also be managed by an endocrinologist throughout childhood.

Calomys callosus: An Experimental Animal Model Applied to Parasitic Diseases Investigations of Public Health Concern

The appearance and spread of parasitic diseases around the world aroused the interest of the scientific community to discover new animal models for improving the quality and specificity of surveys. Calomys callosus is a rodent native to South America, an easy handling model, with satisfactory longevity and reproducibility. C. callosus is susceptible to toxoplasmosis and can be used as experimental model for the study the pathogenesis, treatment, vertical transmission, and ocular toxoplasmosis. C. callosus can also be used to study cutaneous and visceral leishmaniasis, as the animals present cutaneous lesions, as well as parasites in the organs. C. callosus has epidemiological importance in Chagas disease, and since it is a Trypanosoma cruzi natural host in which rodents show high parasitemia and lethality, they are also effective as a model of congenital transmission. In the study of schistosomiasis, Schistosoma mansoni was proven to be a C. callosus natural host; thus, this rodent is a great model for fibrosis, hepatic granulomatous reaction, and celloma associated with lymphomyeloid tissue (CALT) during S. mansoni infection. In this review, we summarize the leading studies of parasitic diseases that used C. callosus as a rodent experimental model, describing the main uses and characteristics that led them to be considered an effective model.

The Impact of Deforestation, Urbanization, and Changing Land Use Patterns on the Ecology of Mosquito and Tick-Borne Diseases in Central America

Central America is a unique geographical region that connects North and South America, enclosed by the Caribbean Sea to the East, and the Pacific Ocean to the West. This region, encompassing Belize, Costa Rica, Guatemala, El Salvador, Honduras, Panama, and Nicaragua, is highly vulnerable to the emergence or resurgence of mosquito-borne and tick-borne diseases due to a combination of key ecological and socioeconomic determinants acting together, often in a synergistic fashion. Of particular interest are the effects of land use changes, such as deforestation-driven urbanization and forest degradation, on the incidence and prevalence of these diseases, which are not well understood. In recent years, parts of Central America have experienced social and economic improvements; however, the region still faces major challenges in developing effective strategies and significant investments in public health infrastructure to prevent and control these diseases. In this article, we review the current knowledge and potential impacts of deforestation, urbanization, and other land use changes on mosquito-borne and tick-borne disease transmission in Central America and how these anthropogenic drivers could affect the risk for disease emergence and resurgence in the region. These issues are addressed in the context of other interconnected environmental and social challenges.

Immunomodulation and Antioxidant Activities as Possible Trypanocidal and Cardioprotective Mechanisms of Major Terpenes from Lippia alba Essential Oils in an Experimental Model of Chronic Chagas Disease

In the late phase of Trypanosoma cruzi infection, parasite persistence and an exaggerated immune response accompanied by oxidative stress play a crucial role in the genesis of Chronic Chagasic Cardiomyopathy (CCC). Current treatments (Benznidazole (BNZ) and Nifurtimox) can effect only the elimination of the parasite, but are ineffective for late stage treatment and for preventing heart damage and disease progression. In vivo trypanocidal and cardioprotective activity has been reported for Lippia alba essential oils (EOs), ascribed to their two major terpenes, limonene and caryophyllene oxide. To investigate the role of antioxidant and immunomodulatory mechanisms behind these properties, chronic-T. cruzi-infected rats were treated with oral synergistic mixtures of the aforementioned EOs. For this purpose, the EOs were optimized through limonene-enrichment fractioning and by the addition of exogenous caryophyllene oxide (LIMOX) and used alone or in combined therapy with subtherapeutic doses of BNZ (LIMOXBNZ). Clinical, toxicity, inflammatory, oxidative, and parasitological (qPCR) parameters were assessed in cardiac tissue. These therapies demonstrated meaningful antioxidant and immunomodulatory activity on markers involved in CCC pathogenesis (IFN-γ, TNF-α, IL-4, IL-10, and iNOS), which could explain their significant trypanocidal properties and their noteworthy role in preventing, and even reversing, the progression of cardiac damage in chronic Chagas disease.

Characterisation of Macrophage Polarisation in Mice Infected with Ninoa Strain of Trypanosoma cruzi

Macrophages (MΦ) play a key role in the development of the protective immune response against Trypanosoma cruzi infection. To determine the role of MΦ subtypes M1 and M2 in the development of immunity against the Mexican strain of T. cruzi (Ninoa strain), we have analysed in a time course the infection and characterised the M1 and M2 subtypes in two mouse models, BALB/c and C57BL/6. After infection, BALB/c mice developed an increased blood parasite load and the parasites were cleared from the blood one week later than in C57BL/6 mice. However, similar cellular infiltrate and cardiac alterations were observed between BALB/c and C57BL/6 mice. At 36 days, the T. cruzi infection differentially modulated the expression of immune cells, and both the BALB/c and C57BL/6 mice significantly reduced TCD4+ cells. However, BALB/c mice produced significantly more TCD8+ than C57BL/6 mice in the spleen and lymph nodes. Furthermore, BALB/c mice produce significantly more MΦ in the spleen, while C57BL/6 produce similar levels to uninfected mice. The M1 MΦ ratio increased significantly at 3-5 days post-infection (dpi), but then decreased slightly. On the contrary, the M2 MΦ were low at the beginning of the infection, but the proportion of M1 and M2 MΦ at 36 dpi was similar. Importantly, the MΦ subtypes M2c and M2d significantly increased the induction of tissue repair by the end of the acute phase of the infection. These results indicate that the Ninoa strain has developed strategies to modulate the immune response, with fine differences depending on the genetic background of the host.

Ruthenium(II)- and Palladium(II)-catalyzed position-divergent CH oxygenations of arylated quinones: Identification of hydroxylated quinonoid compounds with potent trypanocidal activity

A diversity-oriented synthesis of hydroxylated aryl-quinones via CH oxygenation reactions and their evaluation against Trypanosoma cruzi, the etiological agent of Chagas disease, was accomplished. With the use of ruthenium(II)- or palladium(II)-based catalysts, complementary regioselectivities were observed in the hydroxylation reactions and we have identified 9 compounds more potent than benznidazole (Bz) among these novel arylated and hydroxylated quinones. For instance, 5-hydroxy-2-[4-(trifluoromethyl)phenyl]-1,4-naphthoquinone (4h) with an IC₅₀/24 h value of 22.8 µM is 4.5-fold more active than the state-of-the-art drug Bz. This article provides the first example of the application of CH activation for the position-selective hydroxylation of arylated quinones and the identification of these compounds as trypanocidal drug candidates.

Heart transplantation candidacy

PURPOSE OF REVIEW

Timely referral of eligible candidates for consideration of advanced therapies, such as a heart transplantation or mechanical circulatory support is essential. The characteristics of heart transplantation candidates have changed significantly over the years, leading to a more complex evaluation process. The present review summarizes recent advances in the evaluation process for heart transplantation eligibility.

RECENT FINDINGS

The heart transplantation allocation policy was recently reviewed in the USA in an effort to reduce waitlist mortality and to ensure fair geographic allocation of organs to the sickest patients. Moreover, patients with chronic infectious diseases, as well as malignancies, are being currently considered acceptable candidates for transplantation. Listing practices for heart transplantation vary between programmes, with a greater willingness to consider high-risk candidates at higher-volume centres.

SUMMARY

The ultimate decision to place high-risk candidates on the heart transplantation waitlist should be based on a combination of quantitative and qualitative data analysis informed by clinical judgement, and the chronic shortage of organ donors makes this process an important ethical concern for any society. Future guidelines should discuss approaches to achieve fair organ allocation while preserving improved outcomes after transplantation.

Point-of-Care Ultrasound: Applications in Low- and Middle-Income Countries

Purpose of Review

This review highlights the applications of point-of-care ultrasound in low- and middle-income countries and shows the diversity of ultrasound in the diagnosis and management of patients.

Recent Findings

There is a paucity of data on point-of-care ultrasound in anesthesiology in low- and middle-income countries. However, research has shown that point-of-care ultrasound can effectively help manage infectious diseases, as well as abdominal and pulmonary pathologies.

Summary

Point-of-care ultrasound is a low-cost imaging modality that can be used for the diagnosis and management of diseases that affect low- and middle-income countries. There is limited data on the use of ultrasound in anesthesiology, which provides clinicians and researchers opportunity to study its use during the perioperative period.

Trypanocidal Activity of Four Sesquiterpene Lactones Isolated from Asteraceae Species

The sesquiterpene lactones eupatoriopicrin, estafietin, eupahakonenin B and minimolide have been isolated from Argentinean Astearaceae species and have been found to be active against Trypanosoma cruzi epimastigotes. The aim of this work was to evaluate the activity of these compounds by analyzing their effect against the stages of the parasites that are infective for the human. Even more interesting, we aimed to determine the effect of the most active and selective compound on an in vivo model of T. cruzi infection. Eupatoriopicrin was the most active against amastigotes and tripomastigotes (IC₅₀ = 2.3 µg/mL, and 7.2 µg/mL, respectively) and displayed a high selectivity index. This compound was selected to study on an in vivo model of T. cruzi infection. The administration of 1 mg/kg/day of eupatoriopicrin for five consecutive days to infected mice produced a significant reduction in the parasitaemia levels in comparison with non-treated animals (area under parasitaemia curves 4.48 vs. 30.47, respectively). Skeletal muscular tissues from eupatopicrin-treated mice displayed only focal and interstitial lymphocyte inflammatory infiltrates and small areas of necrotic; by contrast, skeletal tissues from T. cruzi infected mice treated with the vehicle showed severe lymphocyte inflammatory infiltrates with necrosis of the adjacent myocytes. The results indicate that eupatoriopicrin could be considered a promising candidate for the development of new therapeutic agents for Chagas disease.

Evaluation of Tpeak–Tend and QT intervals in Chagas’ Disease, Chronic Phase and Normal Electrocardiogram

Introduction: Chagas’ disease lacks elements to predict which carriers will evolve into cardiac form and which will remain in undetermined form. Objective: To evaluate the relationship between electrocardiographic evolution and Tpeak–Tend and QT intervals, both corrected for heart rate, in chagasic patients with normal initial electrocardiogram. Method: Chagasic patients admitted to the institution until 2002 were retrospectively evaluated, and the electrocardiogram was normal at the first consultation. The Tpeak–Tend and QT intervals were measured in milliseconds at the V2 and V5 derivations, with the mean values corrected for heart rate (Bazett). The relationship of these values with the electrocardiographic evolution of the individuals was analyzed, considering the gender, time of evolution and whether they received benznidazole or not. Results: The corrected Tpeak–Tend interval showed no statistical significance among those who maintained or not normal electrocardiogram. The corrected QT interval, the treatment with benznidazole and the time of evolution showed significance for the maintenance of normal electrocardiogram. In the multivariate evaluation, treatment with benznidazole, the QTc interval and the time of evolution were independent variables for the maintenance of normal electrocardiogram. Conclusion: The Tpeak–Tend interval showed no predictor of electrocardiographic evolution. The increased QT interval favored changes.

Avaliação do Intervalo Tpico–Tfim e QT em Doença de Chagas, Fase Crônica e Eletrocardiograma Normal

Introdução: A doença de Chagas carece de elementos que proporcionem prever quais portadores evoluirão para a forma cardíaca e quais permanecerão na forma indeterminada. Objetivo:Avaliar relação entre evolução eletrocardiográfica e intervalos Tpico–Tfim e QT, ambos corrigidos para a frequência cardíaca, em chagásicos com eletrocardiograma inicial normal. Método: Avaliamos retrospectivamente chagásicos admitidos na instituição até 2002, tendo eletrocardiograma normal na primeira consulta. Os intervalos Tpico–Tfim e QT foram medidos em milissegundos nas derivações V2 e V5, sendo a média dos valores corrigida para a frequência cardíaca (Bazett). Analisou-se a relação desses valores com a evolução eletrocardiográfica dos indivíduos, tendo em vista sexo, tempo de evolução e se receberam benzonidazol ou não. Resultados: O intervalo Tpico–Tfim corrigido não mostrou significância estatística entre os que mantiveram ou não eletrocardiograma normal. O intervalo QT corrigido, o tratamento com benzonidazol e o tempo de evolução mostraram significância quanto à manutenção do eletrocardiograma normal. Na avaliação multivariada, o tratamento com benzonidazol, o intervalo QTc e o tempo de evolução se mostraram variáveis independentes para a manutenção do eletrocardiograma normal. Conclusão:O intervalo Tpico–Tfim não se mostrou preditor da evolução eletrocardiográfica. O intervalo QT aumentado favoreceu aparecimento de alterações.

Improving the drug-likeness of inspiring natural products - evaluation of the antiparasitic activity against Trypanosoma cruzi through semi-synthetic and simplified analogues of licarin A

Neolignan licarin A (1) was isolated from leaves of Nectandra oppositifolia (Lauraceae) and displayed activity against trypomastigote forms of the etiologic agent of American trypanosomiasis, Trypanosoma cruzi. Aiming for the establishment of SAR, five different compounds (1a - 1e) were prepared and tested against T. cruzi. The 2-allyl derivative of licarin A (1d) exhibited higher activity against trypomastigotes of T. cruzi (IC50 = 5.0 μM and SI = 9.0), while its heterocyclic derivative 1e displayed IC50 of 10.5 μM and reduced toxicity against NCTC cells (SI > 19.0). However, these compounds presented limited oral bioavailability estimation (<85%, Papp <1.0 × 10-6 cm/s) in parallel artificial membrane permeability assays (PAMPA) due to excessive lipophilicity. Based on these results, different simplified structures of licarin A were designed: vanillin (2), vanillyl alcohol (3), isoeugenol (4), and eugenol (5), as well as its corresponding methyl (a), acetyl (b), O-allyl (c), and C-allyl (d) analogues. Vanillin (2) and its acetyl derivative (2b) displayed expressive activity against intracellular amastigotes of T. cruzi with IC50 values of 5.5 and 5.6 μM, respectively, and reduced toxicity against NCTC cells (CC50 > 200 μM). In addition, these simplified analogues showed a better permeability profile (Papp > 1.0 × 10-6 cm/s) on PAMPA models, resulting in improved drug-likeness. Vanillyl alcohol acetyl derivative (3b) and isoeugenol methyl derivative (4a) displayed activity against the extracellular forms of T. cruzi (trypomastigotes) with IC50 values of 5.1 and 8.8 μM respectively. Based on these results, compounds with higher selectivity index against extracellular forms of the parasite (1d, 1e, 3d, and 4a) were selected for a mechanism of action study. After a short incubation period (1 h) all compounds increased the reactive oxygen species (ROS) levels of trypomastigotes, suggesting cellular oxidative stress. The ATP levels were increased after two hours of incubation, possibly involving a high energy expenditure of the parasite to control the homeostasis. Except for compound 4a, all compounds induced hyperpolarization of mitochondrial membrane potential, demonstrating a mitochondrial imbalance. Considering the unique mitochondria apparatus of T. cruzi and the lethal alterations induced by structurally based on licarin A, these compounds are interesting hits for future drug discovery studies in Chagas disease.

Scaffold and Parasite Hopping: Discovery of New Protozoal Proliferation Inhibitors

Utilizing a target repurposing and parasite-hopping approach, we tested a previously reported library of compounds that were active against Trypanosoma brucei, plus 31 new compounds, against a variety of protozoan parasites including Trypanosoma cruzi, Leishmania major, Leishmania donovani, and Plasmodium falciparum. This led to the discovery of several compounds with submicromolar activities and improved physicochemical properties that are early leads toward the development of chemotherapeutic agents against kinetoplastid diseases and malaria.

Increased heart fibrosis and acute infection in a murine Chagas disease model associated with organophosphorus pesticide metabolite exposure

Some reports suggest that exposure to organophosphorus (OP) pesticides increases the incidence of infections. Ethylated dialkylphosphates (EtDAPs) are metabolites of OP pesticides widely distributed with immunomodulatory potential. Chagas disease is produced by Trypanosoma cruzi parasites, and resolution of this infection requires the activation of inflammatory macrophages (MΦ), which results in cardiac fibrosis. Some reports indicate that EtDAPs increase the amount of the anti-inflammatory alternatively activated MΦ (M2; CD206⁺F4/80⁺). Therefore, we analyzed the course of T. cruzi infection, MΦ profiles from peritoneal exudate cells (PECs), inflammatory cell infiltration and fibrosis in the heart of BALB/c mice exposed to diethyldithiophosphate (DEDTP), diethylthiophosphate (DETP) or diethylphosphate (DEP, 0.01 g/kg), common DAPs produced by OP pesticides, 24 h before infection with T. cruzi. We found that DEDTP increased the parasite burden in blood by 99% at the peak of the infection and enhanced the myocardial damage due to an increase in infiltrated inflammatory cells (induced by DEDTP or DETP) and fibrosis (induced by EtDAPs). In the PECs, exposure to EtDAPs increased the proportion of the MΦ subpopulations of M2a, M2b and M2d, which are associated with tissue repair. These results indicate that exposure to EtDAPs can exacerbate the acute phase of a parasitic infection and increase the long-term damage to the heart.

Why hasn't there been more progress in new Chagas disease drug discovery?

Introduction: Chagas disease (CD) is a neglected disease caused by the protozoan parasite Trypanosoma cruzi. In terms of novel drug discovery, there has been no progress since the 1960s with the same two drugs, benznidazole and nifurtimox, still in use. The complex life cycle, genetic diversity of T. cruzi strains, different sensitivities to the available drugs, as well as little interest from pharmaceutical companies and inadequate methodologies for translating in vitro and in vivo findings to the discovery of new drugs have all contributed to the lack of progress.Areas covered: In this perspective, the authors give discussion to the relevant points connected to the lack of developments in CD drug discovery and provide their expert perspectives.Expert opinion: There are few drugs currently in the preclinical pipeline for the treatment of CD. Only three classes of compounds have been shown to achieve high cure rates in mouse models of infection: nitroimidazoles (fexinidazole), oxaborole DNDi-6148 and proteasome inhibitors (GNF6702). New biomarkers for Chagas' disease are urgently needed for the diagnosis and detection of cure/treatment efficacy. Efforts from academia and pharmaceutical companies are in progress and more intense interaction to accelerate the process of new drugs development is necessary.