IL-18 triggered by the Nlrp3 inflammasome induces host innate resistance in a pulmonary model of fungal infection.

Pathogens are sensed by innate immune receptors that initiate an efficient adaptive immune response upon activation. The elements of the innate immune recognition process for Paracoccidioides brasiliensis include TLR-2, TLR-4, and dectin-1. However, there are additional receptors necessary for the host immune responses to P. brasiliensis. The nucleotide-binding oligomerization domain-like receptor (NLRs), which activate inflammasomes, are candidate receptors that deserve renewed investigation. After pathogen infection, the NLRs form large signaling platforms called inflammasomes, which lead to caspase-1 activation and maturation of proinflammatory cytokines (IL-18 and IL-1ß). In this study, we showed that NLR family pyrin domain-containing 3 (Nlrp3) is required to induce caspase-1 activation and further secretion of IL-1ß and IL-18 by P. brasiliensis-infected macrophages. Additionally, potassium efflux and lysosomal acidification induced by the fungus were important steps in the caspase-1 activation mechanism. Notably, Nlrp3 and caspase-1 knockout mice were more susceptible to infection than were the wild-type animals, suggesting that the Nlrp3-dependent inflammasomes contribute to host protection against P. brasiliensis. This protective effect occurred owing to the inflammatory response mediated by IL-18, as shown by an augmented fungus burden in IL-18 knockout mice. Taken together, our results show that the Nlrp3 inflammasome is essential for resistance against P. brasiliensis because it orchestrates robust caspase-1 activation and triggers an IL-18-dependent proinflammatory response.

Apoptosis-associated speck-like protein containing a caspase recruitment domain inflammasomes mediate IL-1ß response and host resistance to Trypanosoma cruzi infection.

The innate immune response to Trypanosoma cruzi infection comprises several pattern recognition receptors (PRRs), including TLR-2, -4, -7, and -9, as well as the cytosolic receptor Nod1. However, there are additional PRRs that account for the host immune responses to T. cruzi. In this context, the nucleotide-binding oligomerization domain-like receptors (NLRs) that activate the inflammasomes are candidate receptors that deserve renewed investigation. Following pathogen infection, NLRs form large molecular platforms, termed inflammasomes, which activate caspase-1 and induce the production of active IL-1ß and IL-18. In this study, we evaluated the involvement of inflammasomes in T. cruzi infection and demonstrated that apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) inflammasomes, including NLR family, pyrin domain-containing 3 (NLRP3), but not NLR family, caspase recruitment domain-containing 4 or NLR family, pyrin domain-containing 6, are required for triggering the activation of caspase-1 and the secretion of IL-1ß. The mechanism by which T. cruzi mediates the activation of the ASC/NLRP3 pathway involves K⁺ efflux, lysosomal acidification, reactive oxygen species generation, and lysosomal damage. We also demonstrate that despite normal IFN-γ production in the heart, ASC⁻/⁻ and caspase-1⁻/⁻ infected mice exhibit a higher incidence of mortality, cardiac parasitism, and heart inflammation. These data suggest that ASC inflammasomes are critical determinants of host resistance to infection with T. cruzi.

Satisfaction of Emergency Physicians with the Care Provided to Patients with Cardiovascular Diseases in the Northern Region of Minas Gerais.

BACKGROUND: The dissatisfaction of health professionals in emergency services has a negative influence on both the quality of care provided for acute myocardial infarction (AMI) patients and the retention of those professionals. OBJECTIVE: To assess physicians' satisfaction with the structure of care and diagnosis at the emergency services in the Northern Region of Minas Gerais before the implementation of the AMI system of care. METHODS: This cross-sectional study included physicians from the emergency units of the ambulance service (SAMU) and level II, III and IV regional hospitals. Satisfaction was assessed by using the CARDIOSATIS-Team scale. The median score for each item, the overall scale and the domains were calculated and then compared by groups using the non-parametric Mann-Whitney test. Correlation between time since graduation and satisfaction level was assessed using Spearman correlation. A p value < 0.05 was considered significant. RESULTS: Of the 137 physicians included in the study, 46% worked at SAMU. Most of the interviewees showed overall dissatisfaction with the structure of care, and the median score for the overall scale was 2.0 [interquartile range (IQR) 2.0-4.0]. Most SAMU physicians expressed their dissatisfaction with the care provided (54%), the structure for managing cardiovascular diseases (52%), and the technology available for diagnosis (54%). The evaluation of the overall satisfaction evidenced that the dissatisfaction of SAMU physicians was lower when compared to that of hospital emergency physicians. Level III/IV hospital physicians expressed greater overall satisfaction when compared to level II hospital physicians. CONCLUSION: This study showed the overall dissatisfaction of the emergency physicians in the region assessed with the structure of care for cardiovascular emergencies.

TLR3 is required for survival following Coxsackievirus B3 infection by driving T lymphocyte activation and polarization: The role of dendritic cells.

Type B coxsackievirus (CVB) is a common cause of acute and chronic myocarditis, meningitis and pancreatitis, often leading to heart failure and pancreatic deficiency. The polarization of CD4+ T lymphocytes and their cytokine milieu are key factors in the outcome of CVB-induced diseases. Thus, sensing the virus and driving the adaptive immune response are essential for the establishment of a protective immune response. TLR3 is a crucial virus recognition receptor that confers the host with resistance to CVB infection. In the current study, we found that TLR3 expression in dendritic cells plays a role in their activation upon CVB3 infection in vitro, as TLR3-deficient dendritic cells up-regulate CD80 and CD86 to a less degree than WT cells. Instead, they up-regulated the inhibitory molecule PD-L1 and secreted considerably lower levels of TNF-α and IL-10 and a higher level of IL-23. T lymphocyte proliferation in co-culture with CVB3-infected dendritic cells was increased by TLR3-expressing DCs and other cells. Furthermore, in the absence of TLR3, the T lymphocyte response was shifted toward a Th17 profile, which was previously reported to be deleterious for the host. TLR3-deficient mice were very susceptible to CVB3 infection, with increased pancreatic injury and extensive inflammatory infiltrate in the heart that was associated with uncontrolled viral replication. Adoptive transfer of TLR3+ dendritic cells slightly improved the survival of TLR-deficient mice following CVB3 infection. Therefore, our findings highlight the importance of TLR3 signaling in DCs and in other cells to induce activation and polarization of the CD4+ T lymphocyte response toward a Th1 profile and consequently for a better outcome of CVB3 infection. These data provide new insight into the immune-mediated mechanisms by which CVBs are recognized and cleared in order to prevent the development of myocarditis and pancreatitis and may contribute to the design of therapies for enteroviral infections.

Cardiovascular emergencies in primary care: an observational retrospective study of a large-scale telecardiology service.

BACKGROUND: Electrocardiograms (ECGs) are an essential examination for identification and management of cardiovascular emergencies.The aim of this study was to report on the frequency and recognition of cardiovascular emergencies in primary care units. DESIGN AND SETTING: Observational retrospective study assessing consecutive patients whose digital ECGs were sent for analysis to the team of the Telehealth Network of Minas Gerais. METHODS: Data from patients diagnosed with cardiological emergencies in the primary care setting of 750 municipalities in Minas Gerais, Brazil, between March and September 2015, were collected via telephone contact with the healthcare practitioner who performed the ECG. After collection, the data were subjected to statistical analysis. RESULTS: Over the study period, 304 patients with cardiovascular emergencies were diagnosed within primary care. Only 73.4% of these were recognized by the local physicians. Overall, the most frequent ECG abnormalities were acute ischemic patterns (44.7%) and the frequency of such patterns was higher among the ECGs assigned as emergency priority (P = 0.03). It was possible to obtain complete information on 231 patients (75.9%). Among these, the mean age was 65 ± 14.4 years, 57.1% were men and the most prevalent comorbidity was hypertension (68.4%). In total, 77.9% were referred to a unit caring for cases of higher complexity and 11.7% of the patients died. CONCLUSION: In this study, cardiovascular emergencies were misdiagnosed in primary care settings, acute myocardial ischemia was the most frequent emergency and the mortality rate was high.

Ebi3 Prevents Trypanosoma cruzi-Induced Myocarditis by Dampening IFN-γ-Driven Inflammation.

The identification of anti-inflammatory mediators can reveal important targetable molecules capable of counterbalancing Trypanosoma cruzi-induced myocarditis. Composed of Ebi3 and IL-27p28 subunits, IL-27 is produced by myeloid cells and is able to suppress inflammation by inducing IL-10-producing Tr1 cells, thus emerging as a potential candidate to ameliorate cardiac inflammation induced by T. cruzi. Although IL-27 has been extensively characterized as a suppressive cytokine that prevents liver immunopathogenesis after T. cruzi infection, the mechanisms underlying its effects on T. cruzi-induced myocarditis remain largely unknown. Here, wild-type (WT) and Ebi3-deficient animals were intraperitoneally infected with trypomastigotes of T. cruzi Y strain and used to evaluate the potential anti-inflammatory properties of Ebi3 during T. cruzi infection. The survival rates of mice were daily recorded, the frequency of inflammatory cells was analyzed by flow cytometry and inflammatory mediators were measured by ELISA, real-time PCR and PCR array. We reported that T. cruzi-induced myocarditis was prevented by Ebi3. Stressors mainly recognized by TLR2 and TLR4 receptors on myeloid cells were essential to trigger IL-27p28 production. In addition, Ebi3 regulated IFN-γ-mediated myocarditis by promoting an anti-inflammatory environment through IL-10, which was most likely produced by Tr1 cells rather than classical regulatory T cells (Tregs), in the heart tissue of T. cruzi-infected animals. Furthermore, in vivo IFN-γ blockade ameliorated the host survival without compromising the parasite control in the bloodstream. In humans, IL-27p28 was correlated with cardiac protection during Chagas disease. Patients with mild clinical forms of the disease produced high levels of IL-27p28, whereas lower levels were found in those with severe forms. In addition, polymorphic sites at Ebi3 gene were associated with severe cardiomyopathy in patients with Chagas disease. Collectively, we describe a novel regulatory mechanism where Ebi3 dampens cardiac inflammation by modulating the overproduction of IFN-γ, the bona fide culprit of Chagas disease cardiomyopathy.

Regulation of the immune response during infectious myocarditis.

Infectious myocarditis (IM) is a commonly undiagnosed condition that may cause several heart diseases, including dilated cardiomyopathy and chronic heart failure. The understanding of the physiopathology of myocardial inflammation is crucial for a timely diagnosis and for the control of the tissue damage, which may occur in some cases of IM. Of note, some experimental studies suggest that dilated cardiomyopathy could be a consequence of untreated IM. However, further research is required to address the molecular mechanisms that may link these two clinical entities. Here we review the mechanisms involved in the regulation at different levels of the immune response during IM, with a special focus on diagnostic and therapeutic perspectives of molecules that have been linked to the development of IM and the resulting chronic heart diseases.

Satisfaction of Emergency Physicians with the Care Provided to Patients with Cardiovascular Diseases in the Northern Region of Minas Gerais / Satisfação de Médicos dos Serviços de Urgência com o Cuidado às Doenças Cardiovasculares na Região Ampliada Norte de Minas Gerais

Abstract Background: The dissatisfaction of health professionals in emergency services has a negative influence on both the quality of care provided for acute myocardial infarction (AMI) patients and the retention of those professionals. Objective: To assess physicians' satisfaction with the structure of care and diagnosis at the emergency services in the Northern Region of Minas Gerais before the implementation of the AMI system of care. Methods: This cross-sectional study included physicians from the emergency units of the ambulance service (SAMU) and level II, III and IV regional hospitals. Satisfaction was assessed by using the CARDIOSATIS-Team scale. The median score for each item, the overall scale and the domains were calculated and then compared by groups using the non-parametric Mann-Whitney test. Correlation between time since graduation and satisfaction level was assessed using Spearman correlation. A p value < 0.05 was considered significant. Results: Of the 137 physicians included in the study, 46% worked at SAMU. Most of the interviewees showed overall dissatisfaction with the structure of care, and the median score for the overall scale was 2.0 [interquartile range (IQR) 2.0-4.0]. Most SAMU physicians expressed their dissatisfaction with the care provided (54%), the structure for managing cardiovascular diseases (52%), and the technology available for diagnosis (54%). The evaluation of the overall satisfaction evidenced that the dissatisfaction of SAMU physicians was lower when compared to that of hospital emergency physicians. Level III/IV hospital physicians expressed greater overall satisfaction when compared to level II hospital physicians. Conclusion: This study showed the overall dissatisfaction of the emergency physicians in the region assessed with the structure of care for cardiovascular emergencies.

Resumo Fundamentos: A insatisfação dos profissionais de saúde dos serviços de urgência tem influência negativa na qualidade do cuidado ao infarto agudo do miocárdio (IAM) e na fixação desses profissionais. Objetivo: Avaliar a satisfação de médicos com a estrutura de atendimento e diagnóstico de serviços públicos de urgência na Região Ampliada Norte de Minas Gerais, previamente à implantação da linha de cuidado ao IAM. Métodos: Estudo transversal, que incluiu médicos das unidades de emergência do SAMU e de hospitais regionais nível II, III e IV. Foi avaliada a satisfação usando a escala CARDIOSATIS-Team. O escore mediano para cada item, a escala global e os domínios foram calculados e então comparados por grupos, utilizando o teste não paramétrico de Mann-Whitney. Foi avaliada a correlação entre tempo de formação e nível de satisfação com o método de Spearman. Um valor-p < 0,05 foi considerado significativo. Resultados: De 137 médicos incluídos, 46% trabalhavam no SAMU. A maior parte dos entrevistados demonstrou insatisfação geral com a estrutura de atendimento, cuja mediana da escala global foi 2,0 (intervalo interquartil [IQ] 2,0-4,0). A maioria dos médicos do SAMU demonstrou-se insatisfeita quanto a atendimento prestado (54%), estrutura para condução das doenças cardiovasculares (52%) e tecnologia disponível para diagnóstico (54%). Na avaliação da satisfação global, evidenciou-se que a insatisfação dos médicos do SAMU foi menor quando comparada à dos médicos de urgência hospitalar. Os médicos de hospitais nível III/IV demonstraram maior satisfação global quando comparados aos de hospitais nível II. Conclusão: Este estudo demonstrou insatisfação geral dos médicos dos serviços de urgência na região em relação à estrutura de atendimento às emergências cardiovasculares.

Deficient regulatory T cell activity and low frequency of IL-17-producing T cells correlate with the extent of cardiomyopathy in human Chagas' disease.

BACKGROUND: Myocardium damage during Chagas' disease results from the immunological imbalance between pro- and production of anti-inflammatory cytokines and has been explained based on the Th1-Th2 dichotomy and regulatory T cell activity. Recently, we demonstrated that IL-17 produced during experimental T. cruzi infection regulates Th1 cells differentiation and parasite induced myocarditis. Here, we investigated the role of IL-17 and regulatory T cell during human Chagas' disease. METHODOLOGY/PRINCIPAL FINDINGS: First, we observed CD4(+)IL-17(+) T cells in culture of peripheral blood mononuclear cells (PBMC) from Chagas' disease patients and we evaluated Th1, Th2, Th17 cytokine profile production in the PBMC cells from Chagas' disease patients (cardiomyopathy-free, and with mild, moderate or severe cardiomyopathy) cultured with T. cruzi antigen. Cultures of PBMC from patients with moderate and severe cardiomyopathy produced high levels of TNF-α, IFN-γ and low levels of IL-10, when compared to mild cardiomyopathy or cardiomyopathy-free patients. Flow cytometry analysis showed higher CD4(+)IL-17(+) cells in PBMC cultured from patients without or with mild cardiomyopathy, in comparison to patients with moderate or severe cardiomyopathy. We then analyzed the presence and function of regulatory T cells in all patients. All groups of Chagas' disease patients presented the same frequency of CD4(+)CD25(+) regulatory T cells. However, CD4(+)CD25(+) T cells from patients with mild cardiomyopathy or cardiomyopathy-free showed higher suppressive activity than those with moderate and severe cardiomyopathy. IFN-γ levels during chronic Chagas' disease are inversely correlated to the LVEF (P = 0.007, r = -0.614), while regulatory T cell activity is directly correlated with LVEF (P = 0.022, r = 0.500). CONCLUSION/SIGNIFICANCE: These results indicate that reduced production of the cytokines IL-10 and IL-17 in association with high levels of IFN-γ and TNF-α is correlated with the severity of the Chagas' disease cardiomyopathy, and the immunological imbalance observed may be causally related with deficient suppressor activity of regulatory T cells that controls myocardial inflammation.

Cardiovascular emergencies in primary care: an observational retrospective study of a large-scale telecardiology service

ABSTRACT BACKGROUND: Electrocardiograms (ECGs) are an essential examination for identification and management of cardiovascular emergencies.The aim of this study was to report on the frequency and recognition of cardiovascular emergencies in primary care units. DESIGN AND SETTING: Observational retrospective study assessing consecutive patients whose digital ECGs were sent for analysis to the team of the Telehealth Network of Minas Gerais. METHODS: Data from patients diagnosed with cardiological emergencies in the primary care setting of 750 municipalities in Minas Gerais, Brazil, between March and September 2015, were collected via telephone contact with the healthcare practitioner who performed the ECG. After collection, the data were subjected to statistical analysis. RESULTS: Over the study period, 304 patients with cardiovascular emergencies were diagnosed within primary care. Only 73.4% of these were recognized by the local physicians. Overall, the most frequent ECG abnormalities were acute ischemic patterns (44.7%) and the frequency of such patterns was higher among the ECGs assigned as emergency priority (P = 0.03). It was possible to obtain complete information on 231 patients (75.9%). Among these, the mean age was 65 ± 14.4 years, 57.1% were men and the most prevalent comorbidity was hypertension (68.4%). In total, 77.9% were referred to a unit caring for cases of higher complexity and 11.7% of the patients died. CONCLUSION: In this study, cardiovascular emergencies were misdiagnosed in primary care settings, acute myocardial ischemia was the most frequent emergency and the mortality rate was high.

Nitric oxide donor trans-[RuCl([15]aneN)NO] as a possible therapeutic approach for Chagas' disease.

BACKGROUND AND PURPOSE: Benznidazole (Bz) is the therapy currently available for clinical treatment of Chagas' disease. However, many strains of Trypanosoma cruzi parasites are naturally resistant. Nitric oxide (NO) produced by activated macrophages is crucial to the intracellular killing of parasites. Here, we investigate the in vitro and in vivo activities against T. cruzi, of the NO donor, trans-[RuCl([15]aneN(4))NO](2+). EXPERIMENTAL APPROACH: Trans-[RuCl([15]aneN(4))NO](2+)was incubated with a partially drug-resistant T. cruzi Y strain and the anti-proliferative (epimastigote form) and trypanocidal activities (trypomastigote and amastigote) evaluated. Mice were treated during the acute phase of Chagas' disease. The anti-T. cruzi activity was evaluated by parasitaemia, survival rate, cardiac parasitism, myocarditis and the curative rate. KEY RESULTS: Trans-[RuCl([15]aneN(4))NO](2+) was 10- and 100-fold more active than Bz against amastigotes and trypomastigotes respectively. Further, trans-[RuCl([15]aneN(4))NO](2+) (0.1 mM) induced 100% of trypanocidal activity (trypomastigotes forms) in vitro. Trans-[RuCl([15]aneN(4))NO](2+) induced permanent suppression of parasitaemia and 100% survival in a murine model of acute Chagas' disease. When the drugs were given alone, parasitological cures were confirmed in only 30 and 40% of the animals treated with the NO donor (3.33 micromol.kg(-1).day(-1)) and Bz (385 micromol.kg(-1).day(-1)), respectively, but when given together, 80% of the animals were parasitologically cured. The cured animals showed an absence of myocarditis and a normalisation of cytokine production in the sera. In addition, no in vitro toxicity was observed at the tested doses. CONCLUSIONS AND IMPLICATIONS: These findings indicate that trans-[RuCl([15]aneN(4))NO](2+)is a promising lead compound for the treatment of human Chagas' disease.