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.

Telessaúde e Covid-19: experiências da enfermagem e psicologia em Foz do Iguaçu / Telehealth and Covid-19: experiences of nursing and psychology in Foz do Iguaçu

A pandemia do novo coronavírus mostrou a necessidade da utilização de meios tecnológicos no exercício das atividades que envolvem a atenção à saúde. Nesse sentido, pretende-se relatar as atividades desenvolvidas em uma Central de Telessaúde com intervenções de Enfermagem e Psicologia no enfrentamento à Covid-19. Utilizou-se o método de estudo descritivo do tipo relato de experiência, desenvolvido em um projeto de extensão em uma universidade estadual localizada no extremo oeste do Paraná (Unioeste), no município de Foz do Iguaçu. Para este relato constam as atividades desenvolvidas entre abril e julho de 2020. Os resultados revelaram que as intervenções realizadas, tais como escuta qualificada, orientações e encaminhamentos, permitiram a manutenção dos cuidados de prevenção e promoção à saúde. Conclui-se que a experiência vivenciada nos possibilitou perceber que é possível prestar atendimentos na área de Enfermagem e Psicologia mediante uso de tecnologia remota, para evitar maiores agravos na saúde da população. (AU)

The new coronavirus pandemic showed the need to use technological means to carry out activities that involve health care. In this sense, we intend to report the activities developed in a Telehealth Center with Nursing and Psychology interventions to face Covid-19. We used the descriptive study method of the type of experience report, developed in an extension project in a state university located in the extreme west of Paraná (Unioeste), in the city of Foz do Iguaçu. This report includes the activities developed between April and July 2020. The results showed that the interventions performed, such as qualified listening, guidelines and referrals, allowed the maintenance of preventive care and health promotion. It is concluded that the experience made it possible for us to realize that it is possible to provide care in the area of Nursing and Psychology through the use of remote technology, to avoid further damage to the population's health. (AU)

Role of FAK signaling in chagasic cardiac hypertrophy

Abstract Cardiac hypertrophy and dysfunction are a significant complication of chronic Chagas disease, with heart failure, stroke, and sudden death related to disease progression. Thus, understanding the signaling pathways involved in the chagasic cardiac hypertrophy may provide potential targets for pharmacological therapy. Herein, we investigated the implication of focal adhesion kinase (FAK) signaling pathway in triggering hypertrophic phenotype during acute and chronic T. cruzi infection. C57BL/6 mice infected with T. cruzi (Brazil strain) were evaluated for electrocardiographic (ECG) changes, plasma levels of endothelin-1 (ET-1) and activation of signaling pathways involved in cardiac hypertrophy, including FAK and ERK1/2, as well as expression of hypertrophy marker and components of the extracellular matrix in the different stages of T. cruzi infection (60-210 dpi). Heart dysfunction, evidenced by prolonged PR interval and decrease in heart rates in ECG tracing, was associated with high plasma ET-1 level, extracellular matrix remodeling and FAK signaling activation. Upregulation of both FAK tyrosine 397 (FAK-Y397) and serine 910 (FAK-S910) residues phosphorylation as well as ERK1/2 activation, lead to an enhancement of atrial natriuretic peptide gene expression in chronic infection. Our findings highlight FAK-ERK1/2 signaling as a regulator of cardiac hypertrophy in Trypanosoma cruzi infection. Both mechanical stress, induced by cardiac extracellular matrix (ECM) augment and cardiac overload, and ET-1 stimuli orchestrated FAK signaling activation with subsequent activation of the fetal cardiac gene program in the chronic phase of infection, highlighting FAK as an attractive target for Chagas disease therapy.

Natural products from marine red and brown algae against Trypanosoma cruzi

ABSTRACT Various extracts obtained from the red alga Plocamium brasiliense (Greville Howe & Taylor), including a fraction containing crude 5-chloro-1-(E)-chlorovinyl-2,4-dibromo-1,5-dimethylcyclohexane (1) and another containing a mixture of halogenated monoterpenes (F), as well as atomaric acid meroditerpene (2) isolated from brown alga Stypopodium zonale (J. V. Lamouroux) Papenfuss, were evaluated for their activity against Trypanosoma cruzi. The cytotoxic and trypanosomicidal effects of these extracts were evaluated in Vero cells and clinically relevant forms of T. cruzi (amastigotes and trypomastigotes). All extracts from P. brasiliense presented low cytotoxicity and moderate trypanosomicidal effects, except for the hydroalcoholic extract. The crude 1 and F fractions had enhanced trypanocidal activity but showed low selectivity. Moreover, atomaric acid (2) was identified as a hit, demonstrating a potent trypanocidal effect reaching an IC50 <10 µM against two different DTU (Yand high selectivity index (<10). These results identify marine natural products as promising candidates against Chagas disease.

Trypanosoma cruzi down-regulates mechanosensitive proteins in cardiomyocytes

BACKGROUND Cardiac physiology depends on coupling and electrical and mechanical coordination through the intercalated disc. Focal adhesions offer mechanical support and signal transduction events during heart contraction-relaxation processes. Talin links integrins to the actin cytoskeleton and serves as a scaffold for the recruitment of other proteins, such as paxillin in focal adhesion formation and regulation. Chagasic cardiomyopathy is caused by infection by Trypanosoma cruzi and is a debilitating condition comprising extensive fibrosis, inflammation, cardiac hypertrophy and electrical alterations that culminate in heart failure. OBJECTIVES Since mechanotransduction coordinates heart function, we evaluated the underlying mechanism implicated in the mechanical changes, focusing especially in mechanosensitive proteins and related signalling pathways during infection of cardiac cells by T. cruzi. METHODS We investigated the effect of T. cruzi infection on the expression and distribution of talin/paxillin and associated proteins in mouse cardiomyocytes in vitro by western blotting, immunofluorescence and quantitative real-time polymerase chain reaction (qRT-PCR). FINDINGS Talin and paxillin spatial distribution in T. cruzi-infected cardiomyocytes in vitro were altered associated with a downregulation of these proteins and mRNAs levels at 72 h post-infection (hpi). Additionally, we observed an increase in the activation of the focal adhesion kinase (FAK) concomitant with increase in β-1-integrin at 24 hpi. Finally, we detected a decrease in the activation of FAK at 72 hpi in T. cruzi-infected cultures. MAIN CONCLUSION The results suggest that these changes may contribute to the mechanotransduction disturbance evidenced in chagasic cardiomyopathy.

Trypanosoma janseni n. sp. (Trypanosomatida: Trypanosomatidae) isolated from Didelphis aurita (Mammalia: Didelphidae) in the Atlantic Rainforest of Rio de Janeiro, Brazil: integrative taxonomy and phylogeography within the Trypanosoma cruzi clade

BACKGROUND Didelphis spp. are a South American marsupial species that are among the most ancient hosts for the Trypanosoma spp. OBJECTIVES We characterise a new species (Trypanosoma janseni n. sp.) isolated from the spleen and liver tissues of Didelphis aurita in the Atlantic Rainforest of Rio de Janeiro, Brazil. METHODS The parasites were isolated and a growth curve was performed in NNN and Schneider's media containing 10% foetal bovine serum. Parasite morphology was evaluated via light microscopy on Giemsa-stained culture smears, as well as scanning and transmission electron microscopy. Molecular taxonomy was based on a partial region (737-bp) of the small subunit (18S) ribosomal RNA gene and 708 bp of the nuclear marker, glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) genes. Maximum likelihood and Bayesian inference methods were used to perform a species coalescent analysis and to generate individual and concatenated gene trees. Divergence times among species that belong to the T. cruzi clade were also inferred. FINDINGS In vitro growth curves demonstrated a very short log phase, achieving a maximum growth rate at day 3 followed by a sharp decline. Only epimastigote forms were observed under light and scanning microscopy. Transmission electron microscopy analysis showed structures typical to Trypanosoma spp., except one structure that presented as single-membraned, usually grouped in stacks of three or four. Phylogeography analyses confirmed the distinct species status of T. janseni n. sp. within the T. cruzi clade. Trypanosoma janseni n. sp. clusters with T. wauwau in a well-supported clade, which is exclusive and monophyletic. The separation of the South American T. wauwau + T. janseni coincides with the separation of the Southern Super Continent. CONCLUSIONS This clade is a sister group of the trypanosomes found in Australian marsupials and its discovery sheds light on the initial diversification process based on what we currently know about the T. cruzi clade.

The infection of microvascular endothelial cells with ExoU-producing Pseudomonas aeruginosa triggers the release of von Willebrand factor and platelet adhesion

An increased plasma concentration of von Willebrand factor (vWF) is detected in individuals with many infectious diseases and is accepted as a marker of endothelium activation and prothrombotic condition. To determine whether ExoU, a Pseudomonas aeruginosa cytotoxin with proinflammatory activity, enhances the release of vWF, microvascular endothelial cells were infected with the ExoU-producing PA103 P. aeruginosa strain or an exoU-deficient mutant. Significantly increased vWF concentrations were detected in conditioned medium and subendothelial extracellular matrix from cultures infected with the wild-type bacteria, as determined by enzyme-linked immunoassays. PA103-infected cells also released higher concentrations of procoagulant microparticles containing increased amounts of membrane-associated vWF, as determined by flow cytometric analyses of cell culture supernatants. Both flow cytometry and confocal microscopy showed that increased amounts of vWF were associated with cytoplasmic membranes from cells infected with the ExoU-producing bacteria. PA103-infected cultures exposed to platelet suspensions exhibited increased percentages of cells with platelet adhesion. Because no modulation of the vWF mRNA levels was detected by reverse transcription-polymerase chain reaction assays in PA103-infected cells, ExoU is likely to have induced the release of vWF from cytoplasmic stores rather than vWF gene transcription. Such release is likely to modify the thromboresistance of microvascular endothelial cells.

Brote de tirotoxicosis, ciudad de Minas Lavalleja Uruguay / An outbreack of thyrotoxicosis in tje city of Minas Lavalleja country Uruguay

En el período agosto 2003 a abril 2004 se produjo en la ciudad de Minas del departamento de Lavalleja, un broteepidémico de tirotoxicosis, observándose la gran mayoría de loscasos en vecinos del Barrio España y barrios cercanos. El cuadro clínico, el centellograma tiroideo, los exámenes de laboratorio orientaban al diagnóstico de tiroiditis silente, ingesta de yodo ode hormonas tiroideas. Se realizó un estudio descriptivo obteniéndose información de 59 casos. La evolución en el tiempo tiene forma de curva epidémica a fuente única, afectándosepor igual ambos sexos. Se plantea como hipótesis etiológica el aporte de tiroides uhormonatiroidea en la carne que consumieron los casos.

Trypanosoma cruzi-cardiomyocytes: new contributions regarding a better understanding of this interaction

The present paper summarizes new approaches regarding the progress done to the understanding of the interaction of Trypanosoma cruzi-cardiomyocytes. Mannose receptors localized at the surface of heart muscle cell are involved in binding and uptake of the parasite. One of the most striking events in the parasite-heart muscle cells interaction is the disruption of the actin cytoskeleton. We have investigated the regulation of the actin mRNA during the cytopathology induced in myocardial cells by the parasite. T. cruzi invasion increases calcium resting levels in cardiomyocytes. We have previously shown that Ca2+ ATPase of the sarcoplasmic reticulum (SERCA) is involved in the invasion of T. cruzi in cardiomyocytes. Treating the cells with thapsigargin, a drug that binds to all SERCA ATPases and causes depletion of intracellular calcium stores, we found a 75 per cent inhibition in the T. cruzi-cardiomyocytes invasion.

Regulação e localização de RNA mensageiro durante miogênese de células musculares cardíacas e após infecção pelo Trypanosoma cruzi / Regulation and localization of messenger RNA during myogenesis of cardiac muscle cells after infection with Trypanosoma cruzi

Um sistema experimental in vitro foi utilizado para estudar eventos biológicos e moleculares envolvidos na interação Trypanosoma cruzi – cardiomiócitos. As análises de organização do citoesqueleto e de regulação e localização intracelular de RNA mensageiros (RNAm) forneceram elementos para um melhore entendimento do efeito citopatológico induzido nas celular do miocárdio pelo T.c cruzi. O padrão de expressão e de distribuição de componentes estruturais de células musculares foi analisado durante a miogênese cardíaca. Estudos ultra-estruturais e imunofluorescentes revelaram mudanças na organização do citoesqueleto em cardiomiócitos infectados. Um dos eventos mais marcantes foi a quebra das miofibrilas na região onde o parasita intracelular encontrava-se localizado. Microtúbulos e filamentos de desmina também encontravam-se destruídos com a progressão da infecção (48 e 72 h). Avaliamos se estas mudanças no citoesqueleto afetariam a regulação de RNA mensageiros de actina. Nossos dados revelaram uma expressão temporal e seqüencial de RNA mensageiros de isoformas de actina durante a miogênses cardíaca em células normais: ocorreu um aumento nos níveis de RNAm de a-actina cardíaca concomitante com uma diminuição nos níveis de RNAm de beta e gama actina durante a diferenciação de células musculares. A localização intracelular dos RNAm de actina também foi distinta. Mioblastos apresentaram o sinal de RNAm de beta-actina na periferia da célula, enquanto o RNAm de a-actina cardíaca após 72 h de infecção. Em contraste, o RNAm de beta menos actina aumentou 79 porcento após 48 h de infecção. Além disso, a infecção pelo T. cruzi delocalizou o RNAm de beta menos actina da periferia para a região perinuclear. Esta diminuição de RNAm de alfa menos actina cardíaca e aumento de beta menosactina sugere uma reativação do programa genético de células não musculares sob condições patológicas. A análise da distribuição espacial de poli (A) mais RNA e sua quantidade relativa em cardiomiócitos normais e infectados pelo T. cruzi revelaram porcento de redução no conteúdo citoplasmático de células infectadas, a qual foiconcomitante com a proliferação dos parasitas intracelulares.mudanças nos níveis de poli (A)mais RNA durante o ciclo intracelular do parasita também foram observadas. Um aumento no conteúdo de poli (A)mais RNA em formas amastigotas e subseqüente diminuição após diferenciação a formas tripomastigotas indicaram um aumento progressivo no conteúdo de RNA durante a proliferação do parasita intracelular. Além disso, investigamos a distribuição espacial do RNAm de actina e seu produto protéico no T. cruzi. Embora o RNAm de actina tenha sido visualizado no núcleo e citoplasma do parasita, não foi possível detectar a proteína (actina) usando métodos bioquímicos e imunofluorescentes.

Leishmania major: parasite interactions suggesting sexuality

In five experiments, Leishmania (Leishmania) major (MRHO/SU/59/P-strain) grew poorly when seeded in FYTS medium supplemented with 15 per cent fetal calf serum, but presented several peculiar pairs of promastigotes diametrically opposed and attached at their posterior ends (5.8-13.5 per cent). As seen in Giemsa-stained smears, a ring-like line and/or an enlargement, generally occured at the parasite junction. A close proximity of nuclei, which sometimes were difficult to distinguish from each other, was also observed at this junction. Several of these pairs appeared to be composed of fused cells in which the nuclei could be apparently fused, as shown by fluorescence microscopy to detect ß-tubulin and DNA, and by scanning electron microscopy. Under other culture conditions these pairs were absent or occurred at very low rates (0.2-2.2 per cent). Such pairs differ markedly from longitudinally dividing cells and resemble those described in two other Leishmania species, as well as in Herpetomonas megaseliae and Phytomonas davidi, suggesting steps of a putative sexual process.