Current Understanding of Human Polymorphism in Selenoprotein Genes: A Review of Its Significance as a Risk Biomarker.

Selenium has been proven to influence several biological functions, showing to be an essential micronutrient. The functional studies demonstrated the benefits of a balanced selenium diet and how its deficiency is associated with diverse diseases, especially cancer and viral diseases. Selenium is an antioxidant, protecting the cells from damage, enhancing the immune system response, preventing cardiovascular diseases, and decreasing inflammation. Selenium can be found in its inorganic and organic forms, and its main form in the cells is the selenocysteine incorporated into selenoproteins. Twenty-five selenoproteins are currently known in the human genome: glutathione peroxidases, iodothyronine deiodinases, thioredoxin reductases, selenophosphate synthetase, and other selenoproteins. These proteins lead to the transport of selenium in the tissues, protect against oxidative damage, contribute to the stress of the endoplasmic reticulum, and control inflammation. Due to these functions, there has been growing interest in the influence of polymorphisms in selenoproteins in the last two decades. Selenoproteins' gene polymorphisms may influence protein structure and selenium concentration in plasma and its absorption and even impact the development and progression of certain diseases. This review aims to elucidate the role of selenoproteins and understand how their gene polymorphisms can influence the balance of physiological conditions. In this polymorphism review, we focused on the PubMed database, with only articles published in English between 2003 and 2023. The keywords used were "selenoprotein" and "polymorphism". Articles that did not approach the theme subject were excluded. Selenium and selenoproteins still have a long way to go in molecular studies, and several works demonstrated the importance of their polymorphisms as a risk biomarker for some diseases, especially cardiovascular and thyroid diseases, diabetes, and cancer.

Predictors of Trypanosoma cruzi PCR positivity in patients with chronic Chagas disease.

BACKGROUND: A positive Trypanosoma cruzi polymerase chain reaction (PCR) is associated with a worse prognosis in patients with chronic Chagas disease (CD). OBJECTIVES: To study the association of clinical, electrocardiographic, and echocardiographic characteristics and biomarker blood levels with positive T. cruzi PCR in chronic CD. METHODS: This is a single-centre observational cross-sectional study. Positive T. cruzi PCR association with clinical, electrocardiographic, and echocardiographic characteristics, and biomarker blood levels were studied by logistic regression analysis. p values < 0.05 were considered significant. FINDINGS: Among 333 patients with chronic CD (56.4% men; 62 ± 10 years), T. cruzi PCR was positive in 41.1%. Stepwise multivariate logistic regression showed an independent association between positive T. cruzi PCR and diabetes mellitus {odds ratio (OR) 0.53 [95% confidence interval (CI) 0.30-0.93]; p = 0.03}, right bundle branch block [OR 1.78 (95% CI 1.09-2.89); p = 0.02], and history of trypanocidal treatment [OR 0.13 (95% CI 0.04-0.38); p = 0.0002]. Among patients with a history of trypanocidal treatment (n = 39), only four (10%) patients had a positive T. cruzi PCR. MAIN CONCLUSIONS: Among several studied parameters, only diabetes mellitus, right bundle branch block, and history of trypanocidal treatment showed an independent association with positive T. cruzi PCR. History of trypanocidal treatment was a strong protective factor against a positive T. cruzi PCR.

Vascular Growth Factor Inhibition with Bevacizumab Improves Cardiac Electrical Alterations and Fibrosis in Experimental Acute Chagas Disease.

Chagas disease (CD) caused by Trypanosoma cruzi is a neglected illness and a major reason for cardiomyopathy in endemic areas. The existing therapy generally involves trypanocidal agents and therapies that control cardiac alterations. However, there is no treatment for the progressive cardiac remodeling that is characterized by inflammation, microvasculopathy and extensive fibrosis. Thus, the search for new therapeutic strategies aiming to inhibit the progression of cardiac injury and failure is necessary. Vascular Endothelial Growth Factor A (VEGF-A) is the most potent regulator of vasculogenesis and angiogenesis and has been implicated in inducing exacerbated angiogenesis and fibrosis in chronic inflammatory diseases. Since cardiac microvasculopathy in CD is also characterized by exacerbated angiogenesis, we investigated the effect of inhibition of the VEGF signaling pathway using a monoclonal antibody (bevacizumab) on cardiac remodeling and function. Swiss Webster mice were infected with Y strain, and cardiac morphological and molecular analyses were performed. We found that bevacizumab significantly increased survival, reduced inflammation, improved cardiac electrical function, diminished angiogenesis, decreased myofibroblasts in cardiac tissue and restored collagen levels. This work shows that VEGF is involved in cardiac microvasculopathy and fibrosis in CD and the inhibition of this factor could be a potential therapeutic strategy for CD.

Predictors of Trypanosoma cruzi PCR positivity in patients with chronic Chagas disease

BACKGROUND A positive Trypanosoma cruzi polymerase chain reaction (PCR) is associated with a worse prognosis in patients with chronic Chagas disease (CD). OBJECTIVES To study the association of clinical, electrocardiographic, and echocardiographic characteristics and biomarker blood levels with positive T. cruzi PCR in chronic CD. METHODS This is a single-centre observational cross-sectional study. Positive T. cruzi PCR association with clinical, electrocardiographic, and echocardiographic characteristics, and biomarker blood levels were studied by logistic regression analysis. p values < 0.05 were considered significant. FINDINGS Among 333 patients with chronic CD (56.4% men; 62 ± 10 years), T. cruzi PCR was positive in 41.1%. Stepwise multivariate logistic regression showed an independent association between positive T. cruzi PCR and diabetes mellitus {odds ratio (OR) 0.53 [95% confidence interval (CI) 0.30-0.93]; p = 0.03}, right bundle branch block [OR 1.78 (95% CI 1.09-2.89); p = 0.02], and history of trypanocidal treatment [OR 0.13 (95% CI 0.04-0.38); p = 0.0002]. Among patients with a history of trypanocidal treatment (n = 39), only four (10%) patients had a positive T. cruzi PCR. MAIN CONCLUSIONS Among several studied parameters, only diabetes mellitus, right bundle branch block, and history of trypanocidal treatment showed an independent association with positive T. cruzi PCR. History of trypanocidal treatment was a strong protective factor against a positive T. cruzi PCR.

Clinical trials for Chagas disease: etiological and pathophysiological treatment.

Chagas disease (CD) is caused by the flagellate protozoan Trypanosoma cruzi. It is endemic in Latin America. Nowadays around 6 million people are affected worldwide, and 75 million are still at risk. CD has two evolutive phases, acute and chronic. The acute phase is mostly asymptomatic, or presenting unspecific symptoms which makes it hard to diagnose. At the chronic phase, patients can stay in the indeterminate form or develop cardiac and/or digestive manifestations. The two trypanocide drugs available for the treatment of CD are benznidazole (BZ) and nifurtimox (NFX), introduced in the clinic more than five decades ago. WHO recommends treatment for patients at the acute phase, at risk of congenital infection, for immunosuppressed patients and children with chronic infection. A high cure rate is seen at the CD acute phase but better treatment schemes still need to be investigated for the chronic phase. There are some limitations within the use of the trypanocide drugs, with side effects occurring in about 40% of the patients, that can lead patients to interrupt treatment. In addition, patients with advanced heart problems should not be treated with BZ. This is a neglected disease, discovered 114 years ago that still has no drug effective for their chronic phase. Multiple social economic and cultural barriers influence CD research. The high cost of the development of new drugs, in addition to the low economical return, results in the lack of investment. More economic support is required from governments and pharmaceutical companies on the development of more research for CD treatment. Two approaches stand out: repositioning and combination of drugs, witch drastically decrease the cost of this process, when compared to the development of a new drug. Here we discuss the progress of the clinical trials for the etiological and pathophysiological treatment for CD. In summary, more studies are needed to propose a new drug for CD. Therefore, BZ is still the best option for CD. The trials in course should clarify more about new treatment regimens, but it is already possible to indicate that dosage and time of treatment need to be adjusted.

In Chagas disease, transforming growth factor beta neutralization reduces Trypanosoma cruzi infection and improves cardiac performance.

Chronic Chagasic cardiomyopathy (CCC), a progressive inflammatory and fibrosing disease, is the most prominent clinical form of Chagas disease, a neglected tropical disease caused by Trypanosoma cruzi infection. During CCC, the parasite remains inside the cardiac cells, leading to tissue damage, involving extensive inflammatory response and irregular fibrosis. Among the fibrogenic factors is transforming growth factor-ß (TGF-ß), a key cytokine controlling extracellular matrix synthesis and degradation. TGF-ß is involved in CCC onset and progression, with increased serum levels and activation of its signaling pathways in the cardiac tissue, which crucially contributes to fibrosis. Inhibition of the TGF-ß signaling pathway attenuates T. cruzi infection and prevents cardiac damage in an experimental model of acute Chagas disease. The aim of this study was to investigate the effect of TGF-ß neutralization on T. cruzi infection in both in vitro and in vivo pre-clinical models, using the 1D11 monoclonal antibody. To this end, primary cultures of cardiac cells were infected with T. cruzi trypomastigote forms and treated with 1D11. For in vivo studies, 1D11 was administered in different schemes for acute and chronic phase models (Swiss mice infected with 104 parasites from the Y strain and C57BL/6 mice infected with 102 parasites from the Colombian strain, respectively). Here we show that the addition of 1D11 to cardiac cells greatly reduces cardiomyocyte invasion by T. cruzi and the number of parasites per infected cell. In both acute and chronic experimental models, T. cruzi infection altered the electrical conduction, decreasing the heart rate, increasing the PR interval and the P wave duration. The treatment with 1D11 reduced cardiac fibrosis and reversed electrical abnormalities improving cardiac performance. Taken together, these data further support the major role of the TGF-ß signaling pathways in T. cruzi-infection and their biological consequences on parasite/host interactions. The therapeutic effects of the 1D11 antibody are promising and suggest a new possibility to treat cardiac fibrosis in the chronic phase of Chagas' heart disease by TGF-ß neutralization.

Increased angiogenesis parallels cardiac tissue remodelling in experimental acute Trypanosoma cruzi infection.

BACKGROUND: Angiogenesis has been implicated in tissue injury in several noninfectious diseases, but its role in Chagas disease (CD) physiopathology is unclear. OBJECTIVES: The present study aimed to investigate the effect of Trypanosoma cruzi infection on cardiac angiogenesis during the acute phase of experimental CD. METHODS: The signalling pathway involved in blood vessel formation and cardiac remodelling was evaluated in Swiss Webster mice infected with the Y strain of T. cruzi. The levels of molecules involved in the regulation of angiogenesis, such as vascular endothelial growth factor-A (VEGF-A), Flk-1, phosphorylated extracellular-signal-regulated protein kinase (pERK), hypoxia-inducible factor-1α (HIF-1α), CD31, α-smooth muscle actin (α-SMA) and also the blood vessel growth were analysed during T. cruzi infection. Hearts were analysed using conventional histopathology, immunohistochemistry and western blotting. FINDINGS: In this study, our data demonstrate that T. cruzi acute infection in mice induces exacerbated angiogenesis in the heart and parallels cardiac remodelling. In comparison with noninfected controls, the cardiac tissue of T. cruzi-infected mice presented higher levels of (i) HIF-1α, VEGF-A, Flk-1 and pERK; (ii) angiogenesis; (iii) α-SMA+ cells in the tissue; and (iv) collagen -1 deposition around blood vessels and infiltrating throughout the myocardium. MAIN CONCLUSIONS: We observed cardiac angiogenesis during acute experimental T. cruzi infection parallels cardiac inflammation and remodelling.

The perceptions of Brazilian postgraduate students about the impact of COVID-19 on their well-being and academic performance.

This study aimed at identifying the perceptions of Brazilian postgraduate students from all over the country on the impacts of the COVID-19 pandemic on their academic trajectories. Data from 5985 postgraduate students were collected in the end of 2020, through a 37-item questionnaire, including multiple-choice questions, through Google Forms. The questions were divided into blocks with different proposals: personal profile, academic profile, issues related to COVID-19 infection, and issues related to mental health. Our analysis showed that 51.43% were master's degree students; 43.02% were doctorate and 5.55% were specialization students, mostly attending Biological, Health, and Human Sciences post-graduation courses (18.13%, 17.91%, and 17.38%, respectively) of different Brazilian educational institutions, including public (e.g., UFRJ) and private (e.g., PUC) federal universities as well as research institutions (e.g., Fiocruz) from all five regions of Brazil (north, south, southeast, northeast, and center Midwest). Most of them were academically impacted by the COVID-19 pandemic, which also involved psychological aspects such as high levels of anxiety and depression. The results showed readjustments of research projects, and academic activities, which in some particular research fields led to the successful completion through the remote activities. However, efforts are still needed by graduate programs in order to allow greater flexibility in academic activities to fulfill all previous planning and chronograms, in addition to implementing ongoing projects to support students' mental health.

Transforming growth factor-ß as a therapeutic target for the cardiac damage of Chagas disease.

Transforming growth factor beta (TGF-ß) is deeply involved on the pathogenesis of Chagas disease. Our group has been investigating the participation of this pleiotropic cytokine in different aspects of Chagas disease over the last 20 years. Important observations have been made, such as: (i) the ability of Trypanosoma cruzi in activating latent TGF-ß; (ii) the potential involvement of TGF-ß pathway on T. cruzi invasion of host cells; (iii) association of TGF-ß with parasite intracellular replication; (iv) cardiac fibrosis development and maintenance; (v) disruption of Connexin-43 plaque structures and (vi) inflammation and immune response. In this perspective article we intend to discuss the advances of the potential use of new therapies targeting TGF-ß to treat the cardiac alterations of Chagas disease-affected patients.

Increased angiogenesis parallels cardiac tissue remodelling in experimental acute Trypanosoma cruzi infection

BACKGROUND Angiogenesis has been implicated in tissue injury in several noninfectious diseases, but its role in Chagas disease (CD) physiopathology is unclear. OBJECTIVES The present study aimed to investigate the effect of Trypanosoma cruzi infection on cardiac angiogenesis during the acute phase of experimental CD. METHODS The signalling pathway involved in blood vessel formation and cardiac remodelling was evaluated in Swiss Webster mice infected with the Y strain of T. cruzi. The levels of molecules involved in the regulation of angiogenesis, such as vascular endothelial growth factor-A (VEGF-A), Flk-1, phosphorylated extracellular-signal-regulated protein kinase (pERK), hypoxia-inducible factor-1α (HIF-1α), CD31, α-smooth muscle actin (α-SMA) and also the blood vessel growth were analysed during T. cruzi infection. Hearts were analysed using conventional histopathology, immunohistochemistry and western blotting. FINDINGS In this study, our data demonstrate that T. cruzi acute infection in mice induces exacerbated angiogenesis in the heart and parallels cardiac remodelling. In comparison with noninfected controls, the cardiac tissue of T. cruzi-infected mice presented higher levels of (i) HIF-1α, VEGF-A, Flk-1 and pERK; (ii) angiogenesis; (iii) α-SMA+ cells in the tissue; and (iv) collagen -1 deposition around blood vessels and infiltrating throughout the myocardium. MAIN CONCLUSIONS We observed cardiac angiogenesis during acute experimental T. cruzi infection parallels cardiac inflammation and remodelling.

Transforming growth factor-ß as a therapeutic target for the cardiac damage of Chagas disease

Transforming growth factor beta (TGF-β) is deeply involved on the pathogenesis of Chagas disease. Our group has been investigating the participation of this pleiotropic cytokine in different aspects of Chagas disease over the last 20 years. Important observations have been made, such as: (i) the ability of Trypanosoma cruzi in activating latent TGF-β; (ii) the potential involvement of TGF-β pathway on T. cruzi invasion of host cells; (iii) association of TGF-β with parasite intracellular replication; (iv) cardiac fibrosis development and maintenance; (v) disruption of Connexin-43 plaque structures and (vi) inflammation and immune response. In this perspective article we intend to discuss the advances of the potential use of new therapies targeting TGF-β to treat the cardiac alterations of Chagas disease-affected patients.

Perceptions and Feelings of Brazilian Health Care Professionals Regarding the Effects of COVID-19: Cross-sectional Web-Based Survey.

BACKGROUND: The importance of health professionals has been recognized in COVID-19 pandemic-affected countries, especially in those such as Brazil, which is one of the top 3 countries that have been affected in the world. However, the workers' perception of the stress and the changes that the pandemic has caused in their lives vary according to the conditions offered by these affected countries, including salaries, individual protection equipment, and psychological support. OBJECTIVE: The purpose of this study was to identify the perceptions of Brazilian health workers regarding the COVID-19 pandemic impact on their lives, including possible self-contamination and mental health. METHODS: This cross-sectional web-based survey was conducted in Brazil by applying a 32-item questionnaire, including multiple-choice questions by using the Google Forms electronic assessment. This study was designed to capture spontaneous perceptions from health professionals. All questions were mandatory and divided into 2 blocks with different proposals: personal profile and COVID-19 pandemic impact. RESULTS: We interviewed Brazilian health professionals from all 5 Brazilian regions (N=1376). Our study revealed that 1 in 5 (23%) complained about inadequate personal protective equipment, including face shields (234/1376, 17.0%), masks (206/1376, 14.9%), and laboratory coats (138/1376, 10.0%), whereas 1 in 4 health professionals did not have enough information to protect themselves from the coronavirus disease. These professionals had anxiety due to COVID-19 (604/1376, 43.9%), difficulties in sleep (593/1376, 43.1%), and concentrating on work (453/1376, 32.9%). Almost one-third experienced traumatic situations at work (385/1376, 28.0%), which may have led to negative feelings of fear of COVID-19 and sadness. Despite this situation, there was hope and empathy among their positive feelings. The survey also showed that 1 in 5 acquired COVID-19 with the most classic and minor symptoms, including headache (274/315, 87.0%), body pain (231/315, 73.3%), tiredness (228/315, 72.4%), and loss of taste and smell (208/315, 66.0%). Some of their negative feelings were higher than those of noninfected professionals (fear of COVID-19, 243/315, 77.1% vs 509/1061, 48.0%; impotence, 142/315, 45.1% vs 297/1061, 28.0%; and fault, 38/315, 12.1% vs 567/1061, 53.4%, respectively). Another worrying outcome was that 61.3% (193/315) reported acquiring an infection while working at a health facility and as expected, most of the respondents felt affected (344/1376, 25.0%) or very affected (619/1376, 45.0%) by the COVID-19. CONCLUSIONS: In Brazil, the health professionals were exposed to a stressful situation and to the risk of self-contamination-conditions that can spell future psychological problems for these workers. Our survey findings showed that the psychological support for this group should be included in the future health planning of Brazil and of other hugely affected countries to assure a good mental health condition for the medical teams in the near future.

The Search for Biomarkers and Treatments in Chagas Disease: Insights From TGF-Beta Studies and Immunogenetics.

The anti-inflammatory cytokine transforming growth factor beta (TGF-ß) plays an important role in Chagas disease (CD), a potentially life-threatening illness caused by Trypanosoma cruzi. In this review we revisited clinical studies in CD patients combined with in vitro and in vivo experiments, presenting three main sections: an overview of epidemiological, economic, and clinical aspects of CD and the need for new biomarkers and treatment; a brief panorama of TGF-ß roles and its intracellular signaling pathways, and an update of what is known about TGF-ß and Chagas disease. In in vitro assays, TGF-ß increases during T. cruzi infection and modulates heart cells invasion by the parasite fostering its intracellular parasite cycle. TGF-ß modulates host immune response and inflammation, increases heart fibrosis, stimulates remodeling, and slows heart conduction via gap junction modulation. TGF-ß signaling inhibitors reverts these effects opening a promising therapeutic approach in pre-clinical studies. CD patients with higher TGF-ß1 serum level show a worse clinical outcome, implicating a predictive value of serum TGF-ß as a surrogate biomarker of clinical relevance. Moreover, pre-clinical studies in chronic T. cruzi infected mice proved that inhibition of TGF-ß pathway improved several cardiac electric parameters, reversed the loss of connexin-43 enriched intercellular plaques, reduced fibrosis of the cardiac tissue, restored GATA-6 and Tbox-5 transcription, supporting cardiac recovery. Finally, TGF-ß polymorphisms indicate that CD immunogenetics is at the base of this phenomenon. We searched in a Brazilian population five single-nucleotide polymorphisms (-800 G>A rs1800468, -509 C>T rs1800469, +10 T>C rs1800470, +25 G>C rs1800471, and +263 C>T rs1800472), showing that CD patients frequently express the TGF-ß1 gene genotypes CT and TT at position -509, as compared to noninfected persons; similar results were observed with genotypes TC and CC at codon +10 of the TGF-ß1 gene, leading to the conclusion that 509 C>T and +10 T>C TGF-ß1 polymorphisms are associated with Chagas disease susceptibility. Studies in genetically different populations susceptible to CD will help to gather new insights and encourage the use of TGF-ß as a CD biomarker.

Impact of pharmaceutical care on the quality of life of patients with heart failure due to chronic Chagas disease: Randomized clinical trial.

AIMS: Chronic Chagas disease (ChD) has high morbimortality and loss in quality of life due to heart failure (HF). Pharmaceutical care (PC) optimizes clinical treatment and can improve quality of life in HF. We evaluated if PC improves quality of life of patients with ChD and HF. METHODS: Single-blinded, randomized, controlled trial that assigned adult patients with ChD and HF (81 patients; 61 ± 11 years; 48% male) to PC (n = 40) or standard care (n = 41). Quality of life according to SF-36 and Minnesota living with HF questionnaires, incidence of drug-related problems (DRPs), and adherence to medical treatment were determined at baseline and at every 3 months for 1 year. Intention-to-treat analyses were performed by mixed linear model to verify the treatment effect on the changes of these variables throughout the intervention period. RESULTS: Relative changes from baseline to 1 year of follow-up of the domains physical functioning (+16.6 vs -8.5; P < .001), role-physical (+34.0 vs +5.2; P = .01), general health (+19.4 vs -6.1; P < .001), vitality (+11.5 vs. -5.8; P = .003), social functioning (+7.5 vs -13.3; P = .002), and mental health (+9.0 vs -3.7; P = .006) of the SF-36 questionnaire and the Minnesota living with HF questionnaire score (-12.7 vs +4.8; P < .001) were superior in the PC group than in the standard care group. Adherence to medical treatment increased as early as after 3 months of follow-up and DRPs incidence decreased after 6 months of follow-up only in the PC group. CONCLUSIONS: Patients with ChD and HF who received PC presented improved quality of life, decrease in DRP frequency, and increase in medication adherence.

TGF-ß inhibitor therapy decreases fibrosis and stimulates cardiac improvement in a pre-clinical study of chronic Chagas' heart disease.

TGF-ß involvement in Chagas disease cardiomyopathy has been clearly demonstrated. The TGF-ß signaling pathway is activated in the cardiac tissue of chronic phase patients and is associated with an increase in extracellular matrix protein expression. The aim of this study was to investigate the effect of GW788388, a selective inhibitor of TßR1/ALK5, on cardiac function in an experimental model of chronic Chagas' heart disease. To this end, C57BL/6 mice were infected with Trypanosoma cruzi (102 parasites from the Colombian strain) and treated orally with 3mg/kg GW788388 starting at 120 days post-infection (dpi), when 100% of the infected mice show cardiac damage, and following three distinct treatment schedules: i) single dose; ii) one dose per week; or iii) three doses per week during 30 days. The treatment with GW788388 improved several cardiac parameters: reduced the prolonged PR and QTc intervals, increased heart rate, and reversed sinus arrhythmia, and atrial and atrioventricular conduction disorders. At 180 dpi, 30 days after treatment interruption, the GW3x-treated group remained in a better cardiac functional condition. Further, GW788388 treatment reversed the loss of connexin-43 enriched intercellular plaques and reduced fibrosis of the cardiac tissue. Inhibition of the TGF-ß signaling pathway reduced TGF-ß/pSmad2/3, increased MMP-9 and Sca-1, reduced TIMP-1/TIMP-2/TIMP-4, and partially restored GATA-6 and Tbox-5 transcription, supporting cardiac recovery. Moreover, GW788388 administration did not modify cardiac parasite load during the infection but reduced the migration of CD3+ cells to the heart tissue. Altogether, our data suggested that the single dose schedule was not as effective as the others and treatment three times per week during 30 days seems to be the most effective strategy. The therapeutic effects of GW788388 are promising and suggest a new possibility to treat cardiac fibrosis in the chronic phase of Chagas' heart disease by TGF-ß inhibitors.

TGF-ß Polymorphisms Are a Risk Factor for Chagas Disease.

Transforming growth factor ß1 (TGF-ß1) is an important mediator in Chagas disease. Furthermore, patients with higher TGF-ß1 serum levels show a worse clinical outcome. Gene polymorphism may account for differences in cytokine production during infectious diseases. We tested whether TGFB1 polymorphisms could be associated with Chagas disease susceptibility and severity in a Brazilian population. We investigated five single-nucleotide polymorphisms (-800 G>A, -509 C>T, +10 T>C, +25 G>C, and +263 C>T). 152 patients with Chagas disease (53 with the indeterminate form and 99 with the cardiac form) and 48 noninfected subjects were included. Genotypes CT and TT at position -509 of the TGFB1 gene were more frequent in Chagas disease patients than in noninfected subjects. Genotypes TC and CC at codon +10 of the TGFB1 gene were also more frequent in Chagas disease patients than in noninfected subjects. We found no significant differences in the distribution of the studied TGFB1 polymorphisms between patients with the indeterminate or cardiac form of Chagas disease. Therefore, -509 C>T and +10 T>C TGFB1 polymorphisms are associated with Chagas disease susceptibility in a Brazilian population.

Proteins involved on TGF-ß pathway are up-regulated during the acute phase of experimental Chagas disease.

Studies developed by our group in the last years have shown the involvement of TGF-ß in acute and chronic Chagas heart disease, with elevated plasma levels and activated TGF-ß cell signaling pathway as remarkable features of patients in the advanced stages of this disease, when high levels of cardiac fibrosis is present. Imbalance in synthesis and degradation of extracellular matrix components is the basis of pathological fibrosis and TGF-ß is considered as one of the key regulators of this process. In the present study, we investigated the activity of the TGF-ß signaling pathway, including receptors and signaling proteins activation in the heart of animals experimentally infected with Trypanosoma cruzi during the period that mimics the acute phase of Chagas disease. We observed that T. cruzi-infected animals presented increased expression of TGF-ß receptors. Overexpression of receptors was followed by an increased phosphorylation of Smad2/3, p38 and ERK. Furthermore, we correlated these activities with cellular factors involved in the fibrotic process induced by TGF-ß. We observed that the expression of collagen I, fibronectin and CTGF were increased in the heart of infected animals on day 15 post-infection. Correlated with the increased TGF-ß activity in the heart, we found that serum levels of total TGF-ß were significantly higher during acute infection. Taken together, our data suggest that the commitment of the heart associates with increased activity of TGF-ß pathway and expression of its main components. Our results, confirm the importance of this cytokine in the development and maintenance of cardiac damage caused by T. cruzi infection.

Polimorfismo do gene de TGF-beta1 e a correlação com a susceptibilidade e progressão da Doença de Chagas / TGF-beta1 gene polymorphisms and chagas disease susceptibility and progression

Estudos desenvolvidos pelo grupo nos últimos anos demonstram o envolvimento do fator transformador de crescimento beta (TGF-beta) na cardiopatia chagásica, com exacerbação dos seus níveis plasmáticos e da ativação da sua via de sinalização celular como aspectos desenvolvidos por pacientes nos estágios mais avançados da doença, associado também a níveis elevados de fibrose. Pacientes que apresentavam altos níveis de TGF-beta circulantes, após 10 anos de acompanhamento, evoluíram com pior prognóstico da doença. Recentemente, o polimorfismo no códon 10 do gene que codifica o TGF-beta1 foi descrito por influenciar na produção desta citocina. Também foi observado que, em populações da Colômbia e do Peru, o mesmo polimorfismo pode estar envolvido na susceptibilidade à infecção pelo T. cruzi. O presente trabalho avaliou o polimorfismo dos alelos do gene do TGF-beta1 em pacientes na fase crônica da doença de Chagas; incluindo a forma indeterminada e os diversos estágios da forma cardíaca e correlacionou a expressão dos diferentes alelos do TGF-beta1 com os níveis séricos desta citocina e a manifestação clínica da doença de Chagas. Para isso, 181 indivíduos entre pacientes com forma indeterminada ou cardíaca e indivíduos controle foram convidados a participar do trabalho. Foram realizadas análises de cinco polimorfismos de base única (-800 G>A, -509C>T, +10T>C, +25G>C e +263C>T) por PCR e sequenciamento das regiões de interesse. Além disso, os níveis séricos desta molécula e do peptídeo natriurético cerebral (BNP) foram dosados por ELISA. Ao analisar a frequência genotípica nos diferentes polimorfismos, observamos que a frequência do polimorfismo na posição -509 e no códon 10 eram maiores em pacientes portadores da doença que em indivíduos controle. Além disso, os genótipos CT e TT na posição -509 estão associados com altos níveis séricos do TGF-beta1...

Studies developed by our group have shown the involvement of TGF-beta in Chagas heart disease, with exacerbation of their plasma levels and the activation of its cell signaling pathway, as aspects developed by patients in later stages of the disease, also associatedwith high levels of fibrosis. Patients with higher levels of circulating TGF-beta, after 10 years of follow up, progressed with worse prognosis. Recently, the polymorphism at codon 10 in the TGF-beta 1 gene has been described to influence the production of this cytokine. It was also noted that in populations from Colombia and Peru, the same polymorphism may be involved in susceptibility to T. cruzi infection. The present study assessed the polymorphism of thealleles of the TGF-beta 1 gene in patients with chronic Chagas disease: indeterminate and the different stages of cardiac forms, correlating the expression of different alleles of TGF-beta 1, serum levels of this cytokines and the clinical outcome of Chagas disease. For this, 181 control and patients of different stages in the chronic phase of Chagas disease were invited to participate in the study. We investigated, five single nucleotide polymorphisms (-800 G> A,-509C> T + 10T> C + 25G> C and + 263C> T) by PCR and sequencing of fragments were performed. In addition, serum levels of TGF-beta 1 and BNP were measured by ELISA. We observed a significant difference in the frequency at positions -509 and codon 10. Thesegenotypes represent a risk for susceptibility to the development of Chagas disease. Furthermore, CT and TT genotypes at position -509 are associated with higher serum levelsof TGF-beta1. We found a significant association between circulating levels of BNP with the stage of CCC, but, no relationship between the levels of TGF-beta and BNP was observed. Thus, our results suggest that genetic polymorphisms at position -509 and codon 10 of the TGF-beta1 gene may be involved in the susceptibility to the development of Chagas disease...