Water-soluble lectin (WSMoL) from Moringa oleifera seeds treatment recovers glycemic levels and improves left ventricular ejection fraction on Type-2 Diabetes mice model.

Moringa oleifera, a plant widely used in traditional medicine as well as for water purification, contains a lectin on its seeds named WSMoL which modulates several immune characteristics and has shown cardiac safe properties. Here, we tested the hypothesis that WSMoL is able to recover fasting glucose levels and to improve the cardiac left ventricular (LV) function in a type 2 diabetes mellitus (T2DM) mice model. T2DM was induced in adult C57BL/6 mice by combining a high fat diet and low doses of Streptozotocin. Mice were randomly divided in two groups: i. received WSMoL for 21 consecutive days by gavage (T2DM + WSMoL) and ii. received saline solution (T2DM). Metabolic parameters and LV function were assessed. WSMoL was able to reduce fasting blood glucose levels in T2DM mice after 2 weeks of treatment, when compared to T2DM untreated group. Regarding to cardiac LV function, the T2DM + WSMoL group depicted ejection fraction values comparable to non-diabetic group. Our results show: i. WSMoL treatment presented a potent hypoglycemic effect decreasing insulin resistance and ii. WSMoL was able to improve cardiac LV ejection fraction. Collectively, the results presented here show WSMoL as a potential hypoglycemic agent to be tested in T2DM patients.

Progression of heart failure is attenuated by antioxidant therapy with N-acetylcysteine in myocardial infarcted female rats.

This study investigated the therapeutic potential of N-acetylcysteine (NAC) in the treatment of heart failure in female rats. Myocardial infarcted (MI) rats were given NAC (250 mg/kg/day p.o.) during 28 days after surgery (MI + NAC) or vehicle (MI + Placebo), and sham-operated rats received the same treatments (Sham + NAC and Sham + Placebo). Electrocardiographic and echocardiographic analyses were performed in the last week of treatment. Cardiac mRNA levels of types I and II superoxide dismutase (SOD), catalase, types I and III glutathione peroxidase (GPX), nerve growth factor (NGF), ß1-adrenergic receptor (ß1ADR), and type 2 muscarinic receptor (M2R) were assessed. Cardiac levels NADPH oxidase (NOX) activity, total content of reduced thiols, and SOD, GPX, and catalase activity were assessed. Compared to MI + Placebo group, MI + NAC group exhibited decreased NOX activity, increased content of reduced thiols, increased GPX activity, and normalized GPX III mRNA levels (p < 0.05). Heart and lung weights, left ventricular (LV) end-diastolic volume and left atrium/aorta ratio were decreased, while LV posterior wall thickness and ejection fraction were increased in MI + NAC group versus MI + Placebo rats (p < 0.05). Power density of low frequency band was decreased, while power density of high frequency and the root mean square of the successive differences were increased in MI + NAC rats versus MI + Placebo (p < 0.05). These findings indicate that NAC promotes therapeutic effects in the progression of MI-induced heart failure in female rats.

Echocardiographic Measurements in a Preclinical Model of Chronic Chagasic Cardiomyopathy in Dogs: Validation and Reproducibility.

Background: The failure to translate preclinical results to the clinical setting is the rule, not the exception. One reason that is frequently overlooked is whether the animal model reproduces distinctive features of human disease. Another is the reproducibility of the method used to measure treatment effects in preclinical studies. Left ventricular (LV) function improvement is the most common endpoint in preclinical cardiovascular disease studies, while echocardiography is the most frequently used method to evaluate LV function. In this work, we conducted a robust echocardiographic evaluation of LV size and function in dogs chronically infected by Trypanosoma cruzi. Methods and Results: Echocardiography was performed blindly by two distinct observers in mongrel dogs before and between 6 and 9 months post infection. Parameters analyzed included end-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF), and fractional shortening (FS). We observed a significant LVEF and FS reduction in infected animals compared to controls, with no significant variation in volumes. However, the effect of chronic infection in systolic function was quite variable, with EF ranging from 17 to 66%. Using the cut-off value of EF ≤ 40%, established for dilated cardiomyopathy (DCM) in dogs, only 28% of the infected dogs were affected by the chronic infection. Conclusions: The canine model of CCC mimics human disease, reproducing the percentage of individuals that develop heart failure during the chronic infection. It is thus mandatory to establish inclusion criteria in the experimental design of canine preclinical studies to account for the variable effect that chronic infection has on systolic function.

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.

Resveratrol Reverses Functional Chagas Heart Disease in Mice.

Chronic chagasic cardiomyopathy (CCC) develops years after acute infection by Trypanosoma cruzi and does not improve after trypanocidal therapy, despite reduction of parasite burden. During disease, the heart undergoes oxidative stress, a potential causative factor for arrhythmias and contractile dysfunction. Here we tested whether antioxidants/ cardioprotective drugs could improve cardiac function in established Chagas heart disease. We chose a model that resembles B1-B2 stage of human CCC, treated mice with resveratrol and performed electrocardiography and echocardiography studies. Resveratrol reduced the prolonged PR and QTc intervals, increased heart rates and reversed sinus arrhythmia, atrial and atrioventricular conduction disorders; restored a normal left ventricular ejection fraction, improved stroke volume and cardiac output. Resveratrol activated the AMPK-pathway and reduced both ROS production and heart parasite burden, without interfering with vascularization or myocarditis intensity. Resveratrol was even capable of improving heart function of infected mice when treatment was started late after infection, while trypanocidal drug benznidazole failed. We attempted to mimic resveratrol's actions using metformin (AMPK-activator) or tempol (SOD-mimetic). Metformin and tempol mimicked the beneficial effects of resveratrol on heart function and decreased lipid peroxidation, but did not alter parasite burden. These results indicate that AMPK activation and ROS neutralization are key strategies to induce tolerance to Chagas heart disease. Despite all tissue damage observed in established Chagas heart disease, we found that a physiological dysfunction can still be reversed by treatment with resveratrol, metformin and tempol, resulting in improved heart function and representing a starting point to develop innovative therapies in CCC.

Comparison between effects of pressure support and pressure-controlled ventilation on lung and diaphragmatic damage in experimental emphysema.

BACKGROUND: In patients with emphysema, invasive mechanical ventilation settings should be adjusted to minimize hyperinflation while reducing respiratory effort and providing adequate gas exchange. We evaluated the impact of pressure-controlled ventilation (PCV) and pressure support ventilation (PSV) on pulmonary and diaphragmatic damage, as well as cardiac function, in experimental emphysema. METHODS: Emphysema was induced by intratracheal instillation of porcine pancreatic elastase in Wistar rats, once weekly for 4 weeks. Control animals received saline under the same protocol. Eight weeks after first instillation, control and emphysema rats were randomly assigned to PCV (n = 6/each) or PSV (n = 6/each) under protective tidal volume (6 ml/kg) for 4 h. Non-ventilated control and emphysema animals (n = 6/group) were used to characterize the model and for molecular biology analysis. Cardiorespiratory function, lung histology, diaphragm ultrastructure alterations, extracellular matrix organization, diaphragmatic proteolysis, and biological markers associated with pulmonary inflammation, alveolar stretch, and epithelial and endothelial cell damage were assessed. RESULTS: Emphysema animals exhibited cardiorespiratory changes that resemble human emphysema, such as increased areas of lung hyperinflation, pulmonary amphiregulin expression, and diaphragmatic injury. In emphysema animals, PSV compared to PCV yielded: no changes in gas exchange; decreased mean transpulmonary pressure (Pmean,L), ratio between inspiratory and total time (Ti/Ttot), lung hyperinflation, and amphiregulin expression in lung; increased ratio of pulmonary artery acceleration time to pulmonary artery ejection time, suggesting reduced right ventricular afterload; and increased ultrastructural damage to the diaphragm. Amphiregulin correlated with Pmean,L (r = 0.99, p < 0.0001) and hyperinflation (r = 0.70, p = 0.043), whereas Ti/Ttot correlated with hyperinflation (r = 0.81, p = 0.002) and Pmean,L (r = 0.60, p = 0.04). CONCLUSIONS: In the model of elastase-induced emphysema used herein, PSV reduced lung damage and improved cardiac function when compared to PCV, but worsened diaphragmatic injury.

Comparison between Variable and Conventional Volume-Controlled Ventilation on Cardiorespiratory Parameters in Experimental Emphysema.

Emphysema is characterized by loss of lung tissue elasticity and destruction of structures supporting alveoli and capillaries. The impact of mechanical ventilation strategies on ventilator-induced lung injury (VILI) in emphysema is poorly defined. New ventilator strategies should be developed to minimize VILI in emphysema. The present study was divided into two protocols: (1) characterization of an elastase-induced emphysema model in rats and identification of the time point of greatest cardiorespiratory impairment, defined as a high specific lung elastance associated with large right ventricular end-diastolic area; and (2) comparison between variable (VV) and conventional volume-controlled ventilation (VCV) on lung mechanics and morphometry, biological markers, and cardiac function at that time point. In the first protocol, Wistar rats (n = 62) received saline (SAL) or porcine pancreatic elastase (ELA) intratracheally once weekly for 4 weeks, respectively. Evaluations were performed 1, 3, 5, or 8 weeks after the last intratracheal instillation of saline or elastase. After identifying the time point of greatest cardiorespiratory impairment, an additional 32 Wistar rats were randomized into the SAL and ELA groups and then ventilated with VV or VCV (n = 8/group) [tidal volume (VT) = 6 mL/kg, positive end-expiratory pressure (PEEP) = 3 cmH2O, fraction of inspired oxygen (FiO2) = 0.4] for 2 h. VV was applied on a breath-to-breath basis as a sequence of randomly generated VT values (mean VT = 6 mL/kg), with a 30% coefficient of variation. Non-ventilated (NV) SAL and ELA animals were used for molecular biology analysis. The time point of greatest cardiorespiratory impairment, was observed 5 weeks after the last elastase instillation. At this time point, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant (CINC)-1, amphiregulin, angiopoietin (Ang)-2, and vascular endothelial growth factor (VEGF) mRNA levels were higher in ELA compared to SAL. In ELA animals, VV reduced respiratory system elastance, alveolar collapse, and hyperinflation compared to VCV, without significant differences in gas exchange, but increased right ventricular diastolic area. Interleukin-6 mRNA expression was higher in VCV and VV than NV, while surfactant protein-D was increased in VV compared to NV. In conclusion, VV improved lung function and morphology and reduced VILI, but impaired right cardiac function in this model of elastase induced-emphysema.

A combination of stereological methods, biochemistry and electron microscopy for the investigation of drug treatment effects in experimental animals.

Some chemotherapeutic agents used for breast cancer (BC) treatment can induce severe side effects in the ovarian tissue. The combination of cyclophosphamide and docetaxel (TC) is widely used for BC treatment; however, its late effects in the ovary are not completely understood. The main purpose of this study was to evaluate the structural and ultrastructural alterations in the ovarian stroma induced by TC treatment. Wistar rats were divided into two groups: a control group and a TC group. They were euthanized 5 months after the end of treatment, and their plasma and ovaries were collected. Important alterations were noted. The serum estradiol level was significantly reduced in the TC group compared with the control group. Additionally, the number of apoptotic nuclei was higher in the TC group. The role of the inflammatory response in the development of ovarian damage was investigated, and we found an increased number of mast cells and increased expression of TNF-α in the TC group. The involvement of fibrosis was also investigated. The results showed that the TC group had increased expression levels of TGF-ß1, collagen type I (col-I) and collagen type III (col-III) compared with the control group. Ultrastructural analysis revealed the presence of collagen fibrils in the treated group and illustrated that the ovarian tissue architecture was more disorganized in this group than in the control group. The results from this study are important in the study of chemotherapy-induced ovarian failure and provide further insight into the mechanisms involved in the development of this disease.

Adipose Tissue-Derived Mesenchymal Stromal Cells Protect Mice Infected with Trypanosoma cruzi from Cardiac Damage through Modulation of Anti-parasite Immunity.

BACKGROUND: Chagas disease, caused by the protozoan Trypanosoma cruzi (T. cruzi), is a complex disease endemic in Central and South America. It has been gathering interest due to increases in non-vectorial forms of transmission, especially in developed countries. The objective of this work was to investigate if adipose tissue-derived mesenchymal stromal cells (ASC) can alter the course of the disease and attenuate pathology in a mouse model of chagasic cardiomyopathy. METHODOLOGY/PRINCIPAL FINDINGS: ASC were injected intraperitoneally at 3 days post-infection (dpi). Tracking by bioluminescence showed that cells remained in the abdominal cavity for up to 9 days after injection and most of them migrated to the abdominal or subcutaneous fat, an early parasite reservoir. ASC injection resulted in a significant reduction in blood parasitemia, which was followed by a decrease in cardiac tissue inflammation, parasitism and fibrosis at 30 dpi. At the same time point, analyses of cytokine release in cells isolated from the heart and exposed to T. cruzi antigens indicated an anti-inflammatory response in ASC-treated animals. In parallel, splenocytes exposed to the same antigens produced a pro-inflammatory response, which is important for the control of parasite replication, in placebo and ASC-treated groups. However, splenocytes from the ASC group released higher levels of IL-10. At 60 dpi, magnetic resonance imaging revealed that right ventricular (RV) dilation was prevented in ASC-treated mice. CONCLUSIONS/SIGNIFICANCE: In conclusion, the injection of ASC early after T. cruzi infection prevents RV remodeling through the modulation of immune responses. Lymphoid organ response to the parasite promoted the control of parasite burden, while the heart, a target organ of Chagas disease, was protected from damage due to an improved control of inflammation in ASC-treated mice.

(99m)Tc-ixolaris targets glioblastoma-associated tissue factor: in vitro and pre-clinical applications.

BACKGROUND: The clotting initiator protein tissue factor (TF) has recently been described as a potential target that can be exploited to image aggressive tumors. Ixolaris is a specific TF inhibitor that blocks tumor cell procoagulant activity and tumor growth. OBJECTIVE: Herein we evaluated the ability of (99m)Tc-ixolaris to target tumor-derived TF using an orthotopic glioblastoma (GBM) model in mice. METHODS: The right forebrains of Swiss mice were stereotactically inoculated with U87-MG human GBM cells. Histological and immunohistochemical analyses were performed on the resulting tumors after 35-45 days. The biodistribution of (99m)Tc-ixolaris was evaluated by semi-quantitative whole-body scintigraphy and a quantitative analysis of radioactivity in isolated organs. RESULTS: No (99m)Tc-ixolaris uptake was observed in brain of tumor-free mice, independently of the integrity of brain-blood barrier. In contrast, the presence of TF-expressing brain tumor masses determined a significant (99m)Tc-ixolaris uptake. CONCLUSION: (99m)Tc-ixolaris recognized TF-expressing GBM cells in vivo. Given the proposed role of TF in tumor progression, (99m)Tc-ixolaris is a promising radiopharmaceutical agent for quantifying cancer-associated TF in aggressive tumors, including GBM.

Improvement of cardiac function by placenta-derived mesenchymal stem cells does not require permanent engraftment and is independent of the insulin signaling pathway.

INTRODUCTION: The objective of this work was to evaluate the efficacy of placenta-derived mesenchymal stem cell (MSC) therapy in a mouse model of myocardial infarction (MI). Since MSCs can be obtained from two different regions of the human term placenta (chorionic plate or villi), cells obtained from both these regions were compared so that the best candidate for cell therapy could be selected. METHODS: For the in vitro studies, chorionic plate MSCs (cp-MSCs) and chorionic villi MSCs (cv-MSCs) were extensively characterized for their genetic stability, clonogenic and differentiation potential, gene expression, and immunophenotype. For the in vivo studies, C57Bl/6 mice were submitted to MI and, after 21 days, received weekly intramyocardial injections of cp-MSCs for 3 weeks. Cells were also stably transduced with a viral construct expressing luciferase, under the control of the murine stem cell virus (MSCV) promoter, and were used in a bioluminescence assay. The expression of genes associated with the insulin signaling pathway was analyzed in the cardiac tissue from cp-MSCs and placebo groups. RESULTS: Morphology, differentiation, immunophenotype, and proliferation were quite similar between these cells. However, cp-MSCs had a greater clonogenic potential and higher expression of genes related to cell cycle progression and genome stability. Therefore, we considered that the chorionic plate was preferable to the chorionic villi for the isolation of MSCs. Sixty days after MI, cell-treated mice had a significant increase in ejection fraction and a reduction in end-systolic volume. This improvement was not caused by a reduction in infarct size. In addition, tracking of cp-MSCs transduced with luciferase revealed that cells remained in the heart for 4 days after the first injection but that the survival period was reduced after the second and third injections. Quantitative reverse transcription-polymerase chain reaction revealed similar expression of genes involved in the insulin signaling pathway when comparing cell-treated and placebo groups. CONCLUSIONS: Improvement of cardiac function by cp-MSCs did not require permanent engraftment and was not mediated by the insulin signaling pathway.

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.