Cardioprotection Generated by Aerobic Exercise Training is Not Related to the Proliferation of Cardiomyocytes and Angiotensin-(1-7) Levels in the Hearts of Rats with Supravalvar Aortic Stenosis.

BACKGROUND/AIMS: The beneficial effect of aerobic exercise training (ET) on cardiac remodeling caused by supravalvar aortic stenosis (AS) has been demonstrated in experimental studies; however, the mechanisms responsible for improving cardiac function are not entirely understood. We evaluated whether ET-generated cardioprotection in pressure-overloaded rats is dependent on cardiomyocyte proliferation, increased angiotensin-(1-7) (Ang-1-7) levels, and its receptor in the myocardium. METHODS: Eighteen weeks after ascending AS surgery, Wistar rats were randomly assigned to four groups: sedentary control (C-Sed), exercised control (C-Ex), sedentary aortic stenosis (AS-Sed) and exercised aortic stenosis (AS-Ex) groups. The moderate treadmill exercise protocol was performed for ten weeks. The functional capacity was assessed by treadmill exercise testing. Cardiac structure and function were evaluated by echocardiogram. Cardiomyocyte proliferation was evaluated by flow cytometry. Expression of cell cycle regulatory genes as CCND2, AURKB, CDK1, and MEIS1 was verified by RT-qPCR. Cardiac and plasma angiotensin I (Ang I), angiotensin II (Ang II), and Ang-(1-7) levels were analyzed by high-performance liquid chromatography (HPLC). The angiotensin-converting enzyme (ACE) activity was assessed by the fluorometric method and protein expression of AT1 and Mas receptors by Western blot. RESULTS: The AS-Ex group showed reduced left ventricular wall relative thickness and improved ejection fraction; also, it showed decreased gene expression of myocyte cell cycle regulators, ACE, Ang I, Ang II and Ang II/Ang-(1-7) ratio levels compared to AS-Sed group. However, ET did not induce alterations in Ang-(1-7) and cardiac Mas receptor expression and myocyte proliferation. CONCLUSION: Aerobic exercise training improves systolic function regardless of myocyte proliferation and Ang-(1-7)/Mas receptor levels. However, the ET negatively modulates the vasoconstrictor/hypertrophic axis (ACE/Ang II) and decreases the expression of negative regulatory genes of the cell cycle in cardiomyocytes of rats with supravalvular aortic stenosis.

Diagnostic accuracy of interleukin-6, interleukin-10 and tumor necrosis factor alpha cytokine levels in patients with mild cognitive impairment: systematic review and meta-analysis.

There is growing evidence suggesting an association between neurodegeneration and inflammation playing a role in the pathogenesis of age-associated diseases, including Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI). Objective: A systematic review and meta-analysis were performed to verify evidence on the diagnostic accuracy parameters of the inflammatory cytokines interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor alpha (TNF-α). Methods: A search of Medical Literature Analysis and Retrieval System Online (Medline), Scientific Electronic Library Online (SciELO), Web of Science and Science Direct databases was performed and nine observational studies associated with peripheral inflammatory biomarkers in MCI were identified. Mean (±standard deviation - SD) concentrations of these biomarkers and values of true positives, true negatives, false positives and false negatives for MCI and healthy controls (HC) were extracted from these studies. Results: Significantly higher levels of IL-10 were observed in subjects in the MCI group and Mini-Mental State Examination (MMSE) scores were lower compared to HC. For the other investigations, no differences were found between the groups. Our meta-analysis for the TNF-α biomarker revealed high heterogeneity between studies in terms of sensitivity and specificity. Conclusion: These findings do not support the involvement of inflammatory biomarkers for detection of MCI, although significant heterogeneity was observed. More studies are needed to evaluate the role of these cytokines in MCI, as well as in other stages of cognitive decline and all-cause dementias.

Há evidências crescentes que sugerem uma associação entre a neurodegeneração e a inflamação, desempenhando um papel na patogênese de doenças associadas à idade, incluindo a doença de Alzheimer (DA) e o comprometimento cognitivo leve (CCL). Objetivo: Uma revisão sistemática e metanálise foram realizadas para verificar evidências relativas aos parâmetros de acurácia diagnóstica das citocinas inflamatórias interleucina-6 (IL-6), interleucina-10 (IL-10) e fator de necrose tumoral (TNF-α). Métodos: Foi realizada uma busca nas bases de dados Medical Literature Analysis and Retrieval System Online (Medline), Scientific Electronic Library Online (SciELO), Web of Science e Science Direct, e foram identificados nove estudos observacionais associados a biomarcadores inflamatórios periféricos no CCL. As concentrações médias (desvio padrão ­ ±DP) desses biomarcadores e valores de verdadeiros positivos, verdadeiros negativos, falsos positivos e falsos negativos para CCL e controles saudáveis (CS) foram extraídos desses estudos. Resultados: Níveis significativamente mais elevados de IL-10 foram observados em indivíduos do grupo CCL e os escores do Miniexame do Estado Mental foram mais baixos em comparação com o CS. Para as demais investigações não foram encontradas diferenças entre os grupos. Nossa metanálise para o biomarcador TNF-α revelou alta heterogeneidade entre os estudos em termos de sensibilidade e especificidade. Conclusão: Esses achados não apoiam o envolvimento de biomarcadores inflamatórios na detecção do CCL, embora tenha sido observada heterogeneidade significativa. Mais estudos são necessários para avaliar o papel dessas citocinas no CCL, bem como em outros estágios de declínio cognitivo e demências de todas as causas.

Role of SOCS2 in modulating heart damage and function in a murine model of acute Chagas disease.

Infection with Trypanosoma cruzi induces inflammation, which limits parasite proliferation but may result in chagasic heart disease. Suppressor of cytokine signaling 2 (SOCS2) is a regulator of immune responses and may therefore participate in the pathogenesis of T. cruzi infection. SOCS2 is expressed during T. cruzi infection, and its expression is partially reduced in infected 5-lipoxygenase-deficient [knockout (KO)] mice. In SOCS2 KO mice, there was a reduction in both parasitemia and the expression of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), IL-6, IL-10, SOCS1, and SOCS3 in the spleen. Expression of IFN-γ, TNF-α, SOCS1, and SOCS3 was also reduced in the hearts of infected SOCS2 KO mice. There was an increase in the generation and expansion of T regulatory (Treg) cells and a decrease in the number of memory cells in T. cruzi-infected SOCS2 KO mice. Levels of lipoxinA(4) (LXA(4)) increased in these mice. Echocardiography studies demonstrated an impairment of cardiac function in T. cruzi-infected SOCS2 KO mice. There were also changes in calcium handling and in action potential waveforms, and reduced outward potassium currents in isolated cardiac myocytes. Our data suggest that reductions of inflammation and parasitemia in infected SOCS2-deficient mice may be secondary to the increases in Treg cells and LXA(4) levels. This occurs at the cost of greater infection-associated heart dysfunction, highlighting the relevance of balanced inflammatory and immune responses in preventing severe T. cruzi-induced disease.

Cardiomyocyte dysfunction during the chronic phase of Chagas disease.

Chagas disease, which is caused by the parasite Trypanosoma cruzi, is an important cause of heart failure. We investigated modifications in the cellular electrophysiological and calcium-handling characteristics of an infected mouse heart during the chronic phase of the disease. The patch-clamp technique was used to record action potentials (APs) and L-type Ca2+ and transient outward K+ currents. [Ca2+]i changes were determined using confocal microscopy. Infected ventricular cells showed prolonged APs, reduced transient outward K+ and L-type Ca2+ currents and reduced Ca2+ release from the sarcoplasmic reticulum. Thus, the chronic phase of Chagas disease is characterised by cardiomyocyte dysfunction, which could lead to heart failure.

MTHFR Polymorphisms and Cardiac Parameters in Patients with Diabetic Retinopathy.

BACKGROUND: Diabetes Mellitus (DM) is directly associated with cardiovascular dysfunctions and microvascular complications, such as diabetic retinopathy (DR). The association between DR and increased risks of developing cardiovascular diseases has been described. The low activity of the Methylenetetrahydrofolate reductase (MTHFR), an enzyme involved in the metabolism of homocysteine, can lead to hyperhomocysteinemia that has already been related to cardiac outcomes and resistance to insulin. The A1298C and C677T polymorphisms in the MTHFR can reduce enzyme activity. OBJECTIVE: The study aims to analyze the association between MTHFR genotypes and cardiac parameters in patients with DR. METHODS: DM patients diagnosed with DR (n=65) were categorized and compared according to MTHFR genotypes A1298C (AA and AC+CC groups) and C677T (CC and CT+TT) groups; biochemical, cardiological, anthropometric, genetic, lifestyle and vitamin B9 and B12 consumption variables. Fischer's exact test and Poisson regression were performed to assess the relationship between variables. RESULTS: Comparing echocardiographic and electrocardiogram parameters within genotypic groups, we found a significant association between left atrial dilation and C677T polymorphism. Left atrium diameter was higher in the T allele carriers (CT+TT group), with a prevalence ratio of 0.912. This association was confirmed in the regression model, including confounding variables. The other cardiac structural and functional parameters studied were not significantly associated with the A1298C or C677T genotypes. CONCLUSION: The MTHFR C677T genotype may contribute to atrial remodeling in RD patients. We found an association between the diameter of the left atrium and the T allele of the MTHFR C677T polymorphism in patients with DR.

Non-neuronal cholinergic machinery present in cardiomyocytes offsets hypertrophic signals.

Recent work has provided compelling evidence that increased levels of acetylcholine (ACh) can be protective in heart failure, whereas reduced levels of ACh secretion can cause heart malfunction. Previous data show that cardiomyocytes themselves can actively secrete ACh, raising the question of whether this cardiomyocyte derived ACh may contribute to the protective effects of ACh in the heart. To address the functionality of this non-neuronal ACh machinery, we used cholinesterase inhibitors and a siRNA targeted to AChE (acetylcholinesterase) as a way to increase the availability of ACh secreted by cardiac cells. By using nitric oxide (NO) formation as a biological sensor for released ACh, we showed that cholinesterase inhibition increased NO levels in freshly isolated ventricular myocytes and that this effect was prevented by atropine, a muscarinic receptor antagonist, and by inhibition of ACh synthesis or vesicular storage. Functionally, cholinesterase inhibition prevented the hypertrophic effect as well as molecular changes and calcium transient alterations induced by adrenergic overstimulation in cardiomyocytes. Moreover, inhibition of ACh storage or atropine blunted the anti-hypertrophic action of cholinesterase inhibition. Altogether, our results show that cardiomyocytes possess functional cholinergic machinery that offsets deleterious effects of hyperadrenergic stimulation. In addition, we show that adrenergic stimulation upregulates expression levels of cholinergic components. We propose that this cardiomyocyte cholinergic signaling could amplify the protective effects of the parasympathetic nervous system in the heart and may counteract or partially neutralize hypertrophic adrenergic effects.

Proapoptotic Effects of triazol-1,4-Naphthoquinones Involve Intracellular ROS Production and MAPK/ERK Pathway in Human Leukemia Cells.

BACKGROUND: The natural products constitute an important source of antitumor and cytotoxic agents. Naphthoquinones are effectively quinones present in different plants, with demonstrated anticancer activities. A recent study conducted by our group demonstrated the antileukemic potential of two novel triazol-1,4- naphthoquinones derivatives, PTN (2-(4-Phenyl-1H-1,2,3-triazol-1-yl)-1,4-naphthoquinone) and MPTN (2-[4- (4-Methoxyphenyl)-1H-1,2,3-triazol-1-yl]-1,4-naphthoquinone). Although, the mechanisms underlying the proapoptotic effects of PTN and MPTN have not been fully elucidated so far. OBJECTIVE: The aim of this study was to evaluate the proapoptotic mechanism of PTN and MPTN in human acute leukemia cells. METHODS: We used fluorescence microscopy to observe acridine orange and annexin V staining cells. Flow cytometry assay has also been used for ROS quantification, BAX and cytochrome c proteins expression and apoptosis analysis. MTT assay and western blotting technique have been performed as well for MAPK pathway analysis. RESULTS: By using the acridine orange and annexin V staining with fluorescence microscopy, we have characterized the proapoptotic effects of PTN and MPTN in HL-60 cells involving the intrinsic mitochondrial pathway, since these compounds promoted an increase in the intracellular BAX and cytochrome c protein levels (p<0.05). We further demonstrated that apoptosis induction in HL-60 cells was mediated by increasing intracellular ROS levels via ERK but not p38 MAPKs pathway. CONCLUSION: Taken together, these results have demonstrated that PTN and MPTN are promising tools for the development of new anti-leukemic drugs.

Diagnostic accuracy of interleukin-6, interleukin-10 and tumor necrosis factor alpha cytokine levels in patients with mild cognitive impairment: systematic review and meta-analysis / Precisão diagnóstica dos níveis das citocinas IL-6, IL-10 e TNF-α em pacientes com comprometimento cognitivo leve: revisão sistemática e metanálise

ABSTRACT There is growing evidence suggesting an association between neurodegeneration and inflammation playing a role in the pathogenesis of age-associated diseases, including Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI). Objective: A systematic review and meta-analysis were performed to verify evidence on the diagnostic accuracy parameters of the inflammatory cytokines interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor alpha (TNF-α). Methods: A search of Medical Literature Analysis and Retrieval System Online (Medline), Scientific Electronic Library Online (SciELO), Web of Science and Science Direct databases was performed and nine observational studies associated with peripheral inflammatory biomarkers in MCI were identified. Mean (±standard deviation — SD) concentrations of these biomarkers and values of true positives, true negatives, false positives and false negatives for MCI and healthy controls (HC) were extracted from these studies. Results: Significantly higher levels of IL-10 were observed in subjects in the MCI group and Mini-Mental State Examination (MMSE) scores were lower compared to HC. For the other investigations, no differences were found between the groups. Our meta-analysis for the TNF-α biomarker revealed high heterogeneity between studies in terms of sensitivity and specificity. Conclusion: These findings do not support the involvement of inflammatory biomarkers for detection of MCI, although significant heterogeneity was observed. More studies are needed to evaluate the role of these cytokines in MCI, as well as in other stages of cognitive decline and all-cause dementias.

RESUMO Há evidências crescentes que sugerem uma associação entre a neurodegeneração e a inflamação, desempenhando um papel na patogênese de doenças associadas à idade, incluindo a doença de Alzheimer (DA) e o comprometimento cognitivo leve (CCL). Objetivo: Uma revisão sistemática e metanálise foram realizadas para verificar evidências relativas aos parâmetros de acurácia diagnóstica das citocinas inflamatórias interleucina-6 (IL-6), interleucina-10 (IL-10) e fator de necrose tumoral (TNF-α). Métodos: Foi realizada uma busca nas bases de dados Medical Literature Analysis and Retrieval System Online (Medline), Scientific Electronic Library Online (SciELO), Web of Science e Science Direct, e foram identificados nove estudos observacionais associados a biomarcadores inflamatórios periféricos no CCL. As concentrações médias (desvio padrão — ±DP) desses biomarcadores e valores de verdadeiros positivos, verdadeiros negativos, falsos positivos e falsos negativos para CCL e controles saudáveis (CS) foram extraídos desses estudos. Resultados: Níveis significativamente mais elevados de IL-10 foram observados em indivíduos do grupo CCL e os escores do Miniexame do Estado Mental foram mais baixos em comparação com o CS. Para as demais investigações não foram encontradas diferenças entre os grupos. Nossa metanálise para o biomarcador TNF-α revelou alta heterogeneidade entre os estudos em termos de sensibilidade e especificidade. Conclusão: Esses achados não apoiam o envolvimento de biomarcadores inflamatórios na detecção do CCL, embora tenha sido observada heterogeneidade significativa. Mais estudos são necessários para avaliar o papel dessas citocinas no CCL, bem como em outros estágios de declínio cognitivo e demências de todas as causas.

Bioinformatics analysis of non-synonymous variants in the KLF genes related to cardiac diseases.

Kruppel-like Factors (KLF) are responsible for regulating many genes involved in physiological and pathological processes. They are characterized by three conserved zinc-fingers in the DNA-binding domain, wherein mutations could affect the binding efficiency and transcription regulation. This study aimed to perform bioinformatics analysis to determine the most deleterious non-synonymous variants in KLFs involved in cardiac development and diseases, and their effects over the protein structure and stability. Eight hundred and fifty non-synonymous variants were found in seven KLFs related to cardiac diseases. Seventeen algorithms were used to predict the effect of selected variants over the structure and function of seven KLFs. The Top3 variants were selected in each category of conserved and non-conserved residues in the zinc-finger (ZF) domain. KLF5 p.Cys410Phe was the only variant predicted as deleterious in all algorithms, occurring in a conserved residue of zinc ion interaction. KLF15 p.Arg364Pro was the only variant predicted to affect the DNA-binding, and also occurs in a conserved ZF-domain. Our bioinformatics analysis determined potential variants that may lead to development of cardiac diseases, as well as reinforced the importance of KLF analysis in vitro and in vivo.

Cardiorespiratory alterations in rodents experimentally envenomed with Hadruroides lunatus scorpion venom.

BACKGROUND: Hadruroides lunatus is the most abundant scorpion species in the Peruvian central coast, where most of the accidents involving humans are registered. In spite of its prevalence, there are only very few studies on H. lunatus envenomation. The aim of the present study was to analyze the cardiorespiratory alterations caused by H. lunatus envenomation in rodents. METHODS: Wistar rats injected with H. lunatus scorpion venom were submitted to electrocardiography. After euthanasia, rat lungs were collected and histopathologically analyzed. Mouse cardiomyocytes were used to perform immunofluorescence and calcium transient assays. Data were analyzed by ANOVA or Student's t-test. The significance level was set at p < 0.05. RESULTS: It was observed that H. lunatus venom increased heart rate and caused arrhythmia, thereby impairing the heart functioning. Lungs of envenomed animals showed significant alterations, such as diffuse hemorrhage. In addition, immunofluorescence showed that H. lunatus venom was capable of binding to cardiomyocytes. Furthermore, mouse ventricular cardiomyocytes incubated with H. lunatus venom showed a significant decrease in calcium transient, confirming that H. lunatus venom exerts a toxic effect on heart. CONCLUSION: Our results showed that H. lunatus venom is capable of inducing cardiorespiratory alterations, a typical systemic effect of scorpionism, stressing the importance of medical monitoring in envenomation cases.

Functional cross-talk between aldosterone and angiotensin-(1-7) in ventricular myocytes.

High serum levels of aldosterone have been linked to the development of cardiac disease. In contrast, angiotensin (Ang)-(1-7) was extensively shown to possess cardioprotective effects, including the attenuation of cardiac dysfunction induced by excessive mineralocorticoid activation in vivo, suggesting possible interactions between these 2 molecules. Here, we investigated whether there is cross-talk between aldosterone and Ang-(1-7) and its functional consequences for calcium (Ca(2+)) signaling in ventricular myocytes. Short-term effects of aldosterone on Ca(2+) transient were assessed in Fluo-4/AM-loaded myocytes. Confocal images showed that Ang-(1-7) had no effect on Ca(2+) transient parameters, whereas aldosterone increased the magnitude of the Ca(2+) transient. Quite unexpectedly, addition of Ang-(1-7) to aldosterone-treated myocytes further enhanced the amplitude of the Ca(2+) transient suggesting a synergistic effect of these molecules. Aldosterone action on Ca(2+) transient amplitude was mediated by protein kinase A, and was related to an increase in Ca(2+) current (I(Ca)) density. Both changes were not altered by Ang-(1-7). When cardiomyocytes were exposed to aldosterone, increased Ca(2+) spark rate was measured. Ang-(1-7) prevented this change. In addition, a NO synthase inhibitor restored the effect of aldosterone on Ca(2+) spark rate in Ang-(1-7)-treated myocytes and attenuated the synergistic effect of these 2 molecules on Ca(2+) transient. These results indicate that NO plays an important role in this cross-talk. Our results bring new perspectives in the understanding of how 2 prominent molecules with supposedly antagonist cardiac actions cross-talk to synergistically amplify Ca(2+) signals in cardiomyocytes.

Cardiorespiratory alterations in rodents experimentally envenomed with Hadruroides lunatus scorpion venom

Abstract Background Hadruroides lunatus is the most abundant scorpion species in the Peruvian central coast, where most of the accidents involving humans are registered. In spite of its prevalence, there are only very few studies on H. lunatus envenomation. The aim of the present study was to analyze the cardiorespiratory alterations caused by H. lunatus envenomation in rodents. Methods Wistar rats injected with H. lunatus scorpion venom were submitted to electrocardiography. After euthanasia, rat lungs were collected and histopathologically analyzed. Mouse cardiomyocytes were used to perform immunofluorescence and calcium transient assays. Data were analyzed by ANOVA or Student’s t-test. The significance level was set at p< 0.05. Results It was observed that H. lunatus venom increased heart rate and caused arrhythmia, thereby impairing the heart functioning. Lungs of envenomed animals showed significant alterations, such as diffuse hemorrhage. In addition, immunofluorescence showed that H. lunatus venom was capable of binding to cardiomyocytes. Furthermore, mouse ventricular cardiomyocytes incubated with H. lunatus venom showed a significant decrease in calcium transient, confirming that H. lunatus venom exerts a toxic effect on heart. Conclusion Our results showed that H. lunatus venom is capable of inducing cardiorespiratory alterations, a typical systemic effect of scorpionism, stressing the importance of medical monitoring in envenomation cases.

Cardiorespiratory alterations in rodents experimentally envenomed with Hadruroides lunatus scorpion venom

Abstract Background Hadruroides lunatus is the most abundant scorpion species in the Peruvian central coast, where most of the accidents involving humans are registered. In spite of its prevalence, there are only very few studies on H. lunatus envenomation. The aim of the present study was to analyze the cardiorespiratory alterations caused by H. lunatus envenomation in rodents. Methods Wistar rats injected with H. lunatus scorpion venom were submitted to electrocardiography. After euthanasia, rat lungs were collected and histopathologically analyzed. Mouse cardiomyocytes were used to perform immunofluorescence and calcium transient assays. Data were analyzed by ANOVA or Students t-test. The significance level was set at p 0.05. Results It was observed that H. lunatus venom increased heart rate and caused arrhythmia, thereby impairing the heart functioning. Lungs of envenomed animals showed significant alterations, such as diffuse hemorrhage. In addition, immunofluorescence showed that H. lunatus venom was capable of binding to cardiomyocytes. Furthermore, mouse ventricular cardiomyocytes incubated with H. lunatus venom showed a significant decrease in calcium transient, confirming that H. lunatus venom exerts a toxic effect on heart. Conclusion Our results showed that H. lunatus venom is capable of inducing cardiorespiratory alterations, a typical systemic effect of scorpionism, stressing the importance of medical monitoring in envenomation cases.

Investigation of the cardiomyocyte dysfunction in bradykinin type 2 receptor knockout mice.

AIMS: Bradykinin type 2 receptor (B(2)R) is the key component to trigger the intracellular signaling pathway in response to bradykinin under physiological conditions. The present study sought to investigate whether the B(2)R gene deletion will have an impact on myocardial function. MAIN METHODS: Isolated cell shortening, patch-clamp technique, Western blot and confocal microscopy. KEY FINDINGS: Isolated cell shortening measurements showed significant reduction in B(2)R knockout (B(2)R(-/-)) left ventricular cardiac myocytes' shortening. Whole-cell recordings were used to study the electrophysiological aspects of the left ventricular B(2)R(-/-) cardiomyocytes. Results showed: 1) action potential lengthening; 2) unchanged inwardly rectifying K(+) current; 3) reduced transient outward K(+) (I(to)) and L-type Ca(2+) current densities; 5) changes in kinetic properties related to I(to) and I(Ca,L). In addition, transient sarcoplasmic reticulum (SR) Ca(2+) release was found to be smaller in B(2)R(-/-) cardiomyocytes. Importantly, evidence is provided that NO constitutive production is, at least in part, responsible for the reported electrophysiological modifications observed in cardiomyocytes from B(2)R(-/-) mice. Surprisingly, NO is not involved in the SR Ca(2+) release reduction as demonstrated in the present study. SIGNIFICANCE: Taken together, our findings indicate that B(2)R plays a fundamental role in the regulation of cardiac function and Ca(2+) homeostasis, probably through a NO dependent pathway. These results may contribute to our understanding of the kinins participation in the control of cardiac function.