Cyclodextrin Complexes for the Treatment of Chagas Disease: A Literature Review.

Cyclodextrins are ring-shaped sugars used as additives in medications to improve solubility, stability, and sensory characteristics. Despite being widespread, Chagas disease is neglected because of the limitations of available medications. This study aims to review the compounds used in the formation of inclusion complexes for the treatment of Chagas disease, analyzing the incorporated compounds and advancements in related studies. The databases consulted include Scielo, Scopus, ScienceDirect, PubMed, LILACS, and Embase. The keywords used were "cyclodextrin AND Chagas AND disease" and "cyclodextrin complex against Trypanosoma cruzi". Additionally, a statistical analysis of studies on Chagas disease over the last five years was conducted, highlighting the importance of research in this area. This review focused on articles that emphasize how cyclodextrins can improve the bioavailability, therapeutic action, toxicity, and solubility of medications. Initially, 380 articles were identified with the keyword "cyclodextrin AND Chagas disease"; 356 were excluded for not being directly related to the topic, using the keyword "cyclodextrin complex against Trypanosoma cruzi". Over the last five years, a total of 13,075 studies on Chagas disease treatment were found in our literature analysis. The studies also showed interest in molecules derived from natural products and vegetable oils. Research on cyclodextrins, particularly in the context of Chagas disease treatment, has advanced significantly, with studies highlighting the efficacy of molecules in cyclodextrin complexes and indicating promising advances in disease treatment.

Structure-Aided Computational Design of Triazole-Based Targeted Covalent Inhibitors of Cruzipain.

Cruzipain (CZP), the major cysteine protease present in T. cruzi, the ethiological agent of Chagas disease, has attracted particular attention as a therapeutic target for the development of targeted covalent inhibitors (TCI). The vast chemical space associated with the enormous molecular diversity feasible to explore by means of modern synthetic approaches allows the design of CZP inhibitors capable of exhibiting not only an efficient enzyme inhibition but also an adequate translation to anti-T. cruzi activity. In this work, a computer-aided design strategy was developed to combinatorially construct and screen large libraries of 1,4-disubstituted 1,2,3-triazole analogues, further identifying a selected set of candidates for advancement towards synthetic and biological activity evaluation stages. In this way, a virtual molecular library comprising more than 75 thousand diverse and synthetically feasible analogues was studied by means of molecular docking and molecular dynamic simulations in the search of potential TCI of CZP, guiding the synthetic efforts towards a subset of 48 candidates. These were synthesized by applying a Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) centered synthetic scheme, resulting in moderate to good yields and leading to the identification of 12 hits selectively inhibiting CZP activity with IC50 in the low micromolar range. Furthermore, four triazole derivatives showed good anti-T. cruzi inhibition when studied at 50 µM; and Ald-6 excelled for its high antitrypanocidal activity and low cytotoxicity, exhibiting complete in vitro biological activity translation from CZP to T. cruzi. Overall, not only Ald-6 merits further advancement to preclinical in vivo studies, but these findings also shed light on a valuable chemical space where molecular diversity might be explored in the search for efficient triazole-based antichagasic agents.

Prevalence analysis of Chagas disease by age group in an endemic region of Brazil: possible scenario of active vectorial transmission.

Objectives: Chagas disease (CD) is an infectious disease that predominantly affects poor and vulnerable populations. The last estimate conducted by the World Health Organization in Latin America regarding the prevalence of CD occurred more than 10 years ago. However, there is a scarcity of data assessing the magnitude of CD in populations residing in considered high-risk regions. Therefore, this study aimed to assess the seroprevalence of CD in an endemic region in Northern Minas Gerais through serologic screening. Methods: This is a prevalence study conducted in the municipalities of Catuti, Mato Verde, Mirabela, Montes Azul, and São Francisco, Minas Gerais, Brazil. Data collection occurred between December 2021 and December 2022, involving a questionnaire with closed-ended questions. The variables analyzed included serologic test results, stratified age groups, health indicators, and housing conditions. Results: Of the 2978 participants, 272 individuals (9.1%) tested positive for CD serology. In the age group of 4 to 14 years, 15 to 49 years, and 50 years or older, the prevalence of positive serology was 0.8% (95% confidence interval [CI] 0.16-1.43), 5.5% (95% CI 4.20-6.83), and 18.8% (95% CI 16.48-21.11), respectively. Among the participating municipalities, Mato Verde had the highest prevalence of positive serology for CD (17%). For participants aged 4 to 14 years with positive serology for CD, first-degree relatives were invited to undergo serologic testing. It was possible to collect samples from relatives of all participants in this age group. However, none of the relatives tested positive. Conclusion: This study identified a 9.1% prevalence of individuals affected by CD who were unaware of their condition. In addition, having infected children in the 4 to 14 age group with mothers with negative serology would rule out congenital transmission of the disease.

Acute Chagas disease outbreaks in Colombia in 2019.

This study seeks to address the critical knowledge gap surrounding the acute phase of Chagas disease in Colombia, with a specific focus on cases reported in 2019. The acute phase of Chagas disease is a pivotal period for intervention, yet it remains poorly understood, particularly in regions where oral transmission is presumed to be a significant factor. By analyzing these recent cases, our research aims to provide a deeper understanding of the dynamics of Chagas disease during its acute phase in Colombia in 2019. This understanding is essential not only for improving disease management and treatment strategies but also for enhancing public health responses to this neglected tropical disease. In particular, our study highlights the importance of identifying and addressing the unique challenges posed by oral transmission routes, which have been increasingly recognized within Colombia's Chagas disease landscape.

To Explore Potential Natural Inhibitors of Cysteine Proteases to Combat Human African Trypanosomiasis and Chagas Disease.

BACKGROUND: Human African Trypanosomiasis (HAT), also known as sleeping sickness, and Chagas disease are neglected tropical diseases caused by Trypanosoma brucei and Trypanosoma cruzi, respectively. These diseases present significant challenges in treatment due to the toxicity, low efficacy, and drug-resistant strains associated with current therapies. INTRODUCTION: Cysteine proteases play vital roles in the life cycles of these parasites, making them potential targets for therapeutic intervention. Natural inhibitors sourced from plants, marine organisms, and microorganisms show promise for developing novel therapies. METHODS: This review surveys the potential of natural inhibitors as therapeutic agents against HAT and Chagas disease. It compiles PubMed and PubChem information from various studies to provide an overview of their activities and characteristics, including their ability to inhibit cysteine proteases, modulate the host immune response, and interfere with other parasite proteins. RESULTS: Several natural inhibitors, such as berberine, curcumin, and tannins, have been identified and characterized. These inhibitors have demonstrated encouraging outcomes in both in vitro and in vivo experiments, indicating their potential as therapeutic agents for HAT and Chagas disease. CONCLUSION: Natural inhibitors of cysteine proteases offer a promising avenue for developing novel therapies against HAT and Chagas disease. Further research is needed to identify additional natural inhibitors and optimize their efficacy and safety for human use. The significance of this study lies in its potential to contribute to the discovery of effective, safe, and affordable treatments for these neglected tropical diseases.

Trypanosoma cruzi reprograms mitochondrial metabolism within the anterior midgut of its vector Rhodnius prolixus during the early stages of infection.

BACKGROUND: Trypanosoma cruzi is transmitted to humans by hematophagous bugs belonging to the Triatominae subfamily. Its intra-vectorial cycle is complex and occurs exclusively in the insect's midgut. Dissecting the elements involved in the cross-talk between the parasite and its vector within the digestive tract should provide novel targets for interrupting the parasitic life cycle and affecting vectorial competence. These interactions are shaped by the strategies that parasites use to infect and exploit their hosts, and the host's responses that are designed to detect and eliminate parasites. The objective of the current study is to characterize the impact of T. cruzi establishment within its vector on the dynamics of its midgut. METHODS: In this study, we evaluated the impact of T. cruzi infection on protein expression within the anterior midgut of the model insect Rhodnius prolixus at 6 and 24 h post-infection (hpi) using high-throughput quantitative proteomics. RESULTS: Shortly after its ingestion, the parasite modulates the proteome of the digestive epithelium by upregulating 218 proteins and negatively affecting the expression of 11 proteins involved in a wide array of cellular functions, many of which are pivotal due to their instrumental roles in cellular metabolism and homeostasis. This swift response underscores the intricate manipulation of the vector's cellular machinery by the parasite. Moreover, a more in-depth analysis of proteins immediately induced by the parasite reveals a pronounced predominance of mitochondrial proteins, thereby altering the sub-proteomic landscape of this organelle. This includes various complexes of the respiratory chain involved in ATP generation. In addition to mitochondrial metabolic dysregulation, a significant number of detoxifying proteins, such as antioxidant enzymes and P450 cytochromes, were immediately induced by the parasite, highlighting a stress response. CONCLUSIONS: This study is the first to illustrate the response of the digestive epithelium upon contact with T. cruzi, as well as the alteration of mitochondrial sub-proteome by the parasite. This manipulation of the vector's physiology is attributable to the cascade activation of a signaling pathway by the parasite. Understanding the elements of this response, as well as its triggers, could be the foundation for innovative strategies to control the transmission of American trypanosomiasis, such as the development of targeted interventions aimed at disrupting parasite proliferation and transmission within the triatomine vector.

Vitamin D treatment distinctly modulates cytokine production by peripheral blood mononuclear cells among patients with chronic cardiac and indeterminate clinical forms of Chagas disease.

INTRODUCTION: Chagas disease is caused by the protozoan Trypanosoma cruzi and is clinically divided into acute and chronic phases. Chronic Chagas cardiomyopathy is the most studied manifestation of the disease. Vitamin D deficiency has been suggested as a risk factor for cardiovascular disease. No studies demonstrate the action of this hormone in the cells of patients with chronic Chagas heart disease. OBJECTIVE: To evaluate the in vitro immunomodulatory effect of vitamin D on peripheral blood mononuclear cells of patients with the different chronic clinical forms of Chagas disease. Evaluating vitamin D's in vitro effect on blood cells by producing cytokines. METHODS: Thirteen patients of the undetermined form (IND), 13 of the mild cardiac form (CARD1) and 14 of the severe cardiac form (CARD2) of Chagas disease, and 12 with idiopathic heart disease (CARDid) were included. The cells obtained from peripheral blood were treated in vitro with vitamin D (1 × 10-7 M) for 24 h and cytokines were dosed in the culture supernatant. RESULTS: Although it was not possible to demonstrate statistically significant differences between the groups studied, our data showed that the cells treated with vitamin D modify (p < .05) the production of interferon-γ (IFN-γ) (decrease in IND), tumor necrosis factor-α (TNF-α) (decreased in CARD1 and CARDid), interleukin (IL)-6 (increased in all groups), and IL-10 (decreased in CARD1, CARD2, and CARDid) when compared to untreated cells. CONCLUSION: In vitro treatment with vitamin D distinctly modulated the production of cytokines by mononuclear cells of peripheral blood among patients with chronic and indeterminate cardiac clinical forms of Chagas disease.

Prevalence of Chagas disease among Latin American immigrants in non-endemic countries: an updated systematic review and meta-analysis.

Background: Chagas disease (CD), endemic in 21 Latin American countries, has gradually spread beyond its traditional borders due to migratory movements and emerging as a global health concern. We conducted a systematic review and meta-analysis of available data to establish updated prevalence estimates of CD in Latin American migrants residing in non-endemic countries. Methods: A systematic search was conducted in MEDLINE/PubMed, Embase, Cochrane Library, Scopus, Web of Science, and LILACS via Virtual Health Library (Biblioteca Virtual em Saúde - BVS), including references published until November 1st, 2023. Pooled prevalence estimates and 95% confidence intervals (CI) were calculated using random effect models. Heterogeneity was assessed by the chi-square test and the I2 statistic. Subgroup analyses were performed to explore potential sources of heterogeneity among studies. The study was registered in the PROSPERO database (CRD42022354237). Findings: From a total of 1474 articles screened, 51 studies were included. Studies were conducted in eight non-endemic countries (most in Spain), between 2006 and 2023, and involving 82,369 screened individuals. The estimated pooled prevalence of CD in Latin American migrants living in non-endemic countries was 3.5% (95% CI: 2.5-4.7; I2: 97.7%), considering studies in which screening was indicated simply because the person was Latin American. Per subgroups, the pooled CD prevalence was 11.0% (95% CI: 7.7-15.5) in non-targeted screening (unselected population in reference centers) (27 studies); in blood donors (4 studies), the pooled prevalence was 0.8% (95% CI: 0.2-3.4); among people living with HIV Latin American immigrants (4 studies) 2.4% (95% CI: 1.4-4.3) and for Latin American pregnant and postpartum women (14 studies) 3.7% (95 CI: 2.4-5.6). The pooled proportion of congenital transmission was 4.4% (95% CI: 3.3-5.8). Regarding the participants' country of origin, 7964 were from Bolivia, of which 1715 (21,5%) were diagnosed with CD, and 21,304 were from other Latin American countries of which 154 (0,72%) were affected. Interpretation: CD poses a significant burden of disease in Latin American immigrants in non-endemic countries, suggesting that CD is no longer a problem limited to the American continent and must be considered as a global health challenge. Funding: This study was funded by the World Heart Federation, through a research collaboration with Novartis Pharma AG.

Quality assurance of serologic testing for Chagas disease in a primary care setting of rural Paraguay.

The diagnosis of Chagas disease mostly relies on the use of multiple serologic tests that are often unavailable in many of the remote settings where the disease is highly prevalent. In the Teniente Irala Fernández Municipality, in central Paraguay, efforts have been made to increase the diagnostic capabilities of specific rural health centres, but no quality assurance of the results produced has been performed. We comparatively analysed the results obtained with 300 samples tested using a commercial rapid diagnostic test (RDT) and enzyme linked immunosorbent assays (ELISA) at the laboratory of the Teniente Irala Fernández Health Center (CSTIF) with those generated upon repeating the tests at an independent well-equipped research laboratory (CEDIC). A subgroup of 52 samples were further tested at Paraguay's Central Public Health Laboratory (LCSP) by means of a different technique to evaluate the diagnostic performance of the tests carried out at CSTIF. We observed an excellent agreement between the ELISA results obtained at CSTIF and CEDIC (kappa coefficients between 0.85 and 0.93 for every kit evaluated), and an overall good performance of the tests carried out at CSTIF. However, the sensitivity of one kit was lower at CSTIF (81.3 %) than at CEDIC (100 %). The individual use of an RDT to detect the infection at CSTIF showed a similar sensitivity to that obtained combining it to an ELISA test (92.3% vs 88.5, p = 1). Nonetheless, the generalizability of this result is yet limited and will require of further studies.

Structural dynamics of the TPR domain of the peroxisomal cargo receptor Pex5 in Trypanosoma.

Peroxisomal protein import has been identified as a valid target in trypanosomiases, an important health threat in Central and South America. The importomer is built of multiple peroxins (Pex) and structural characterization of these proteins facilitates rational inhibitor development. We report crystal structures of the Trypanosoma brucei and T. cruzi tetratricopeptide repeat domain (TPR) of the cytoplasmic peroxisomal targeting signal 1 (PTS1) receptor Pex5. The structure of the TPR domain of TbPex5 represents an apo-form of the receptor which, together with the previously determined structure of the complex of TbPex5 TPR and PTS1 demonstrate significant receptor dynamics associated with signal peptide recognition. The structure of the complex of TPR domain of TcPex5 with PTS1 provided in this study details the molecular interactions that guide signal peptide recognition at the atomic level in the pathogenic species currently perceived as the most relevant among Trypanosoma. Small - angle X - ray scattering (SAXS) data obtained in solution supports the crystallographic findings on the compaction of the TPR domains of TbPex5 and TcPex5 upon interaction with the cargo.

Unraveling the Missing Pieces: Exploring the Gaps in Understanding Chagas Cardiomyopathy.

Chagas cardiomyopathy affects a considerable number of patients infected with the protozoan Trypanosoma cruzi (T. cruzi) and remains one of the most neglected tropical diseases despite being a significant contributor to morbidity and mortality in both endemic regions of Latin America and non-endemic countries like the United States. Since its discovery almost a century ago, knowledge gaps still exist in the mechanisms involved in the pathogenesis of Chagas cardiomyopathy, and numerous challenges exist in its diagnosis and treatment. This article reviews the main pathogenetic mechanisms involved in the progression of Chagas cardiomyopathy, which has been proposed as a result of years of research. It also emphasizes the challenges involved in the diagnosis of the asymptomatic indeterminate phase and has focused on several diagnostic techniques, including echocardiography, electrocardiogram (ECG), magnetic resonance imaging (MRI), and nuclear imaging in diagnosing symptomatic Chagas cardiomyopathy. In this article, we have also provided a brief overview of the current treatment of Chagas cardiomyopathy, which is not etiology-specific but instead derived from the knowledge acquired from the treatment of other cardiomyopathies.

A Rhodnius prolixus catalytically inactive Calpain protease patterns the insect embryonic dorsal-ventral axis.

The calcium dependent Calpain proteases are modulatory enzymes with important roles in cell cycle control, development and immunity. In the fly model Drosophila melanogaster Calpain A cleaves Cactus/IkappaB and consequently modifies Toll signals during embryonic dorsal-ventral (DV) patterning. Here we explore the role of Calpains in the hemiptera Rhodnius prolixus, an intermediate germband insect where the Bone Morphogenetic Protein (BMP) instead of the Toll pathway plays a major role in DV patterning. Phylogenetic analysis of Calpains in species ranging from Isoptera to Diptera indicates an increase of Calpain sequences in the R. prolixus genome and other hemimetabolous species. One locus encoding each of the CalpC, CalpD and Calp7 families, and seven Calpain A/B loci are present in the R. prolixus genome. Several predicted R. prolixus Calpains display a unique architecture, such as loss of Calcium-binding EF-hand domains and loss of catalytic residues in the active site CysPc domain, yielding catalytically dead Calpains A/B. Knockdown for one of these inactive Calpains results in embryonic DV patterning defects, with expansion of ventral and lateral gene expression domains and consequent failure of germ band elongation. In conclusion, our results reveal that Calpains may exert a conserved function in insect DV patterning, despite the changing role of the Toll and BMP pathways in defining gene expression territories along the insect DV axis.

Copaifera spp. oleoresins control Trypanosoma cruzi infection in human trophoblast cells (BeWo) and placental explants.

Congenital Chagas disease (CCD) is a worldwide neglected problem with significant treatment limitations. This study aimed to evaluate the potential of Copaifera spp. oleoresins (ORs) against Trypanosoma cruzi infection in trophoblast cells (BeWo lineage) and human chorionic villous explants (HCVE). The cytotoxicity of ORs was investigated using LDH and MTT assays. T. cruzi (Y strain) proliferation, invasion and reversibility were assessed in OR-treated BeWo cells, and proliferation was evaluated in OR-treated HCVE. The ultrastructure of T. cruzi trypomastigotes and amastigotes treated with ORs were analyzed by scanning and transmission electronic microscopy. ROS production in infected and treated BeWo cells and cytokines in BeWo and HCVE were measured. The ORs irreversibly decreased T. cruzi invasion, proliferation and release in BeWo cells by up to 70 %, 82 % and 80 %, respectively, and reduced parasite load in HCVE by up to 80 %. Significant structural changes in treated parasites were observed. ORs showed antioxidant capacity in BeWo cells, reducing ROS production induced by T. cruzi infection. Also, T. cruzi infection modulated the cytokine profile in both BeWo cells and HCVE; however, treatment with ORs upregulated cytokines decreased by T. cruzi infection in BeWo cells, while downregulated cytokines increased by the T. cruzi infection in HCVE. In conclusion, non-cytotoxic concentrations of Copaifera ORs demonstrated promising potential for controlling T. cruzi infection in models of the human maternal-fetal interface.

Impact of gastrointestinal inoculation and benznidazole treatment on infection by Trypanosoma cruzi (Y strain, DTU TcII) in Swiss mice.

In Brazil, where Chagas disease is endemic, the most frequent form of transmission of the parasite is the oral route, associated with greater severity and worse response to benznidazole (BZ), the drug used in its treatment. This study aimed to evaluate the impact of gastrointestinal infection (GI) and BZ treatment on the parasitological and histopathological parameters in mice inoculated with a strain of T. cruzi II. Swiss mice were inoculated by GI and intraperitoneal (IP) routes with 2x106 culture-derived metacyclic trypomastigotes of the Y strain (TcII) of T. cruzi and were treated with BZ in the acute phase of the infection. Fresh blood examination, qPCR, histopathological and biochemical evaluations (enzymatic dosages and oxidative stress-OS) were performed. BZ treatment of uninfected animals caused changes in the liver, increased the activity of aspartate aminotransferase and alanine aminotransferase enzymes and OS, showing that the drug alone affects this organ. Inflammation and necrosis in the cardiac tissue were less intense and deaths occurred later in animals inoculated via the GI route than the animals inoculated via the IP route. BZ reduced the intensity of tissue lesions and avoided lethality in animals inoculated via the GI route, and decreased parasitemia and OS in those inoculated via both routes. Although BZ alone caused liver damage, it was less intense than that caused by both routes of inoculation. Infection with the Y strain of T. cruzi II via the GI route proved to be less virulent and pathogenic and responded better to treatment than the infection acquired via the IP route.

Chagas Disease in the Non-Endemic Area of Rome, Italy: Ten Years of Experience and a Brief Overview.

Chagas disease (CD) is a parasitic infection endemic in Latin America and also affects patients in Western countries due to migration flows. This has a significant impact on health services worldwide due to its high morbidity and mortality burden. This paper aims to share our experience at the National Institute for Infectious Diseases "Lazzaro Spallanzani", IRCCS, in Rome, Italy, where to date, a total of 47 patients-mainly Bolivian women-diagnosed with CD have received treatment with benznidazole, with all but one presenting with chronic disease. Most of the patients were recruited through the first extensive screening program held in 2014 at our Institute. About a quarter of our patients showed adverse effects to benznidazole, including a case of severe drug-induced liver injury, but 83% completed a full course of treatment. In addition to the description of our cohort, the paper reports a brief overview of the disease compiled through a review of the existing literature on CD in non-endemic countries. The growing prevalence of CD in Western countries highlights the importance of screening at-risk populations and urges public concern and medical awareness about this neglected tropical disease. There are still many unanswered questions that need to be addressed to develop a personalized approach in treating patients.

Cardioembolic stroke in Chagas disease: unraveling the underexplored connection through a systematic review.

BACKGROUND: Chagas disease (CD), triggered by the Trypanosoma cruzi parasite, is originally endemic across Latin America, affecting millions. While cardiac complications are widely recognized, the association between CD and stroke remains underexplored. This systematic review aims to elucidate the relationship between CD and stroke, highlighting the cardioembolic origins of stroke in CD patients and assessing the elevated stroke risk compared to non-infected individuals. METHODOLOGY: Adhering to the PRISMA guidelines, we conducted a comprehensive search in PubMed and Scopus databases without date restrictions, including articles in both Spanish and English. This approach enabled the identification and analysis of relevant studies to understand the interplay between CD and stroke risk. RESULTS: Our analysis of 25 selected studies indicates that strokes in CD patients predominantly arise from cardioembolic sources. The data underscore a significant increase in stroke risk among individuals infected with T. cruzi compared to uninfected counterparts. Additionally, CD patients face a higher stroke and mortality risk than those with other heart failure etiologies, irrespective of disease severity. CONCLUSION: The review establishes CD as a critical contributor to stroke incidence, emphasizing the need for heightened awareness and diagnosis of CD in stroke patients, particularly in regions with high CD prevalence. Recognizing the increased stroke risk associated with T. cruzi infection is crucial for developing targeted educational and preventive strategies in endemic areas.

Recombinant proteins as promising antigens applied to the immunodiagnosis of Chagas disease: a scoping review.

Chagas disease (CD), caused by the protozoan Trypanosoma cruzi, is an important public health problem, occurring mainly in Latin America. The disease has a major social and economical effect, negatively impacting the life of the infected individuals, and bringing great costs to public health. An early and accurate diagnosis is essential for administration of early treatment. In addition, prognostic tests may aid disease management, decreasing hospitalization costs. However, the serological diagnostic scenario for CD still faces several challenges, making the development of new diagnostic kits a pressing matter. Facing this scenario, several researchers have expanded efforts in developing and testing new antigens, such as recombinant proteins and recombinant multiepitope proteins, with promising results. These recombinant antigens offer several advantages, such as improved sensitivity and specificity, in addition to facilitated scaling. Also, it has been possible to observe a rising number of studies using ELISA and point-of-care platforms, employing these antigens in the past few years. Among them, recombinant proteins were the most applied antigens, demonstrating great capacity to discriminate between positive and negative samples. Although fewer in number, recombinant multiepitope proteins also demonstrated an improved diagnostic performance. Indeed, a great number of studies employing these antigens showed sensitivity and specificity values above 90%, greatly impacting diagnostic accuracy. Nevertheless, despite the good results found, it is still possible to observe some bottlenecks in the development of new antigens, such as the scarcity of tests with sera from the acute phase and the variability of results in different geographic areas. In this sense, aiming to contribute to control and health programs, the continuous search for a more accurate serological diagnosis is essential, both for the acute and chronic phases of the disease.

Aminopyridines in the development of drug candidates against protozoan neglected tropical diseases.

Neglected tropical diseases (NTDs) pose a major threat in tropical zones for impoverished populations. Difficulty of access, adverse effects or low efficacy limit the use of current therapeutic options. Therefore, development of new drugs against NTDs is a necessity. Compounds containing an aminopyridine (AP) moiety are of great interest for the design of new anti-NTD drugs due to their intrinsic properties compared with their closest chemical structures. Currently, over 40 compounds with an AP moiety are on the market, but none is used against NTDs despite active research on APs. The aim of this review is to present the medicinal chemistry work carried out with these scaffolds, against protozoan NTDs: Trypanosoma cruzi, Trypanosoma brucei or Leishmania spp.

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The effects of inflammation on connexin 43 in chronic Chagas disease cardiomyopathy.

Background: Cardiac arrhythmias are the main cause of sudden death due to Chronic Chagasic Cardiomyopathy (CCC). Here we investigated alterations in connexin 43 (Cx43) expression and phosphorylation in cardiomyocytes as well as associations with cardiac arrhythmias in CCC. Methods: C57Bl/6 mice infected with Trypanosoma cruzi underwent cardiac evaluations at 6 and 12 months after infection via treadmill testing and EKG. Histopathology, cytokine gene expression, and distribution of total Cx43 and its phosphorylated forms Cx43S368 and Cx43S325/328/330 were investigated. Human heart samples obtained from subjects with CCC were submitted to immunofluorescence analysis. In vitro simulation of a pro-inflammatory microenvironment (IL-1ß, TNF, and IFN-γ) was performed in H9c2 cells and iPSC-derived cardiomyocytes to evaluate Cx43 distribution, action potential duration, and Lucifer Yellow dye transfer. Results: Mice chronically infected with T. cruzi exhibited impaired cardiac function associated with increased inflammation, fibrosis and upregulated IL-1ß, TNF, and IFN-γ gene expression. Confocal microscopy revealed altered total Cx43, Cx43S368 and Cx43S325/328/330 localization and phosphorylation patterns in CCC, with dispersed staining outside the intercalated disc areas, i.e., in lateral membranes and the cytoplasm. Reduced co-localization of total Cx43 and N-cadherin was observed in the intercalated discs of CCC mouse hearts compared to controls. Similar results were obtained in human CCC heart samples, which showed Cx43 distribution outside the intercalated discs. Stimulation of human iPSC-derived cardiomyocytes or H9c2 cells with IL-1ß, TNF, and IFN-γ induced alterations in Cx43 localization, reduced action potential duration and dye transfer between adjacent cells. Conclusion: Heart inflammation in CCC affects the distribution and phosphorylation pattern of Cx43, which may contribute to the generation of conduction disturbances in Chagas disease.