Electrocontractile remodeling of isolated cardiomyocytes induced during early-stage hypercholesterolemia.

Hypercholesterolemia is one of the most important risk factors for cardiovascular diseases. However, it is mostly associated with vascular dysfunction and atherosclerotic lesions, while evidence of direct effects of hypercholesterolemia on cardiomyocytes and heart function is still incomplete and controversial. In this study, we assessed the direct effects of hypercholesterolemia on heart function and the electro-contractile properties of isolated cardiomyocytes. After 5 weeks, male Swiss mice fed with AIN-93 diet added with 1.25% cholesterol (CHO), developed an increase in total serum cholesterol levels and cardiomyocytes cholesterol content. These changes led to altered electrocardiographic records, with a shortening of the QT interval. Isolated cardiomyocytes displayed a shortening of the action potential duration with increased rate of depolarization, which was explained by increased IK, reduced ICa.L and altered INa voltage-dependent inactivation. Also, reduced diastolic [Ca2+]i was found with preserved adrenergic response and cellular contraction function. However, contraction of isolated hearts is impaired in isolated CHO hearts, before and after ischemia/reperfusion, although CHO heart was less susceptible to arrhythmic contractions. Overall, our results demonstrate that early hypercholesterolemia-driven increase in cellular cholesterol content is associated with direct modulation of the heart and cardiomyocytes' excitability, Ca2+ handling, and contraction.

Hepatic arterial buffer response: activation in donor fetuses and the effect of laser ablation of intertwin anastomosis.

OBJECTIVES: Hepatic arterial buffer response (HABR) is an important defence mechanism for maintaining liver blood flow. It is suspected that HABR is active in monochorionic diamniotic twins (MCDA) with twin-to-twin transfusion syndrome (TTTS) where donor compensates a setting of volume depletion and the recipient an overload. The present study investigates whether in TTTS, HABR is active in donor and/or recipient individually and try to determine if the activation of HABR is a direct response to TTTS. METHODS: Hepatic artery (HA) peak systolic velocity (PSV) was measured in normal MCDA fetuses and TTTS. Correlation with relevant fetal Dopplers and characteristics were determined. Z-scores for HA-PSV (HAV-Z) were calculated and its association with TTTS in donors and recipients were determined as well as changes in HAV-Z after laser treatment. RESULTS: In this study 118 MCDA were included, 61.9 % normal and 38.1 % TTTS. Of the TTTS 22 required laser treatment. A total of 382 scans were performed in normal group and 155 in TTTS. Our data demonstrates that in donors HAV-Z was 2.4 Z-scores higher compared to normal fetuses (ß=2.429 95 % CI 1.887, 2.971; p<0.001) and after laser treatment HAV-Z reduced (ß=-1.829 95 % CI -2.593, -1.064; p<0.001). There was no significant difference between recipients and normal (ß=-0.092 95 % CI -0.633, 0.449; p=0.738). CONCLUSIONS: HABR is active in TTTS, promoting an increased hepatic blood flow in donors. The activation is direct response to TTTS as shown by the reduction in HAV-Z after laser. This finding provides important insights into the pathophysiology of TTTS.

Hepatic arterial buffer response in monochorionic twins with selective fetal growth restriction.

OBJECTIVES: Monochorionic twins (MC) have higher risk of perinatal morbi-mortality compared to singletons and dichorionic twins (DC). Selective fetal growth restriction (sFGR) increases the chances of adverse outcome. Hepatic arterial buffer response (HABR) is an important mechanism for maintaining liver perfusion. We hypothesised that HABR is active in monochorionic diamniotic twins (MCDA) with sFGR where restricted fetus may have liver hypoperfusion. The objective of this study is to test whether the HAV-ratio is diminished in pregnancies affected by selective fetal growth restriction pointing to activation of HABR in the growth-restricted fetus. METHODS: sFGR was defined according to a consensus definition. Hepatic artery (HA) peak systolic velocity (PSV) was measured and its correlation with fetal Dopplers and pregnancy characteristics were determined. A ratio using HA-PSV (HAV-ratio) was calculated and its association with sFGR was established. Further analysis of HA-PSV was performed comparing z-scores between normal and growth restricted fetuses. RESULTS: We included 202 MCDA pregnancies, 160 (79 %) normal and 42 (21 %) with sFGR. HAV-ratio was significant different between groups. The mean HAV-ratio was 1.01 (±0.20) for normal twins and 0.77 (±0.25) for sFGR. Furthermore, HA-PSV z-scores was significant increased in in growth-restricted fetus (0.94±1.45), while in normal fetuses was -0.16 (±0.97). CONCLUSIONS: Our findings demonstrate that, in pregnancies with sFGR, HAV-ratio is significantly lower than in normal MCDA pregnancies. The lower HAV-ratio is due to an increase in HA PSV in the growth restricted fetus. This observation indicates an activation of HABR in the small fetus.

Hepatic arterial buffer response in monochorionic diamniotic pregnancies with twin-to-twin transfusion syndrome.

OBJECTIVES: Hepatic arterial buffer response (HABR) is an important regulatory process for hepatic blood flow. Its activity has been described in some fetal adverse conditions but in twin-to-twin transfusion syndrome (TTTS) it is unknown if such response is present. The aim of this study is to test the hypothesis that HABR operates in monochorionic diamniotic twins (MCDA) with TTTS. METHODS: Hepatic artery pulsatility index (PI) and peak systolic velocity (PSV) were measured prospectively in 64 MCDA pregnancies. 43 without TTTS (group 1) and in 21 pregnancies with TTTS (group 2). We calculated ratios for PI (HAPI-ratio) and PSV (HAV-ratio) between recipient and donor in group 2 or bigger and smaller fetus in group 1 and compared groups. The association of HAV-ratio and HAPI ratio with TTTS, relation with other fetal Dopplers and reliability of measurement by a single operator were investigated. RESULTS: HAV-ratio and HAPI-ratio appears to be independent from fetal Dopplers, estimated weight and gestational age. In group 2, HAV-ratio is lower than group 1 (p<0.001, 95% CI 0.443-0.643). In group 1 the mean HAV-ratio is 1.014 (±0.021) while in group 2 is 0.47 (±0.035). HAPI-ratio is lower in group 2 than in group 1 although this difference was not significant (p=0.066, 95% CI -0.007-0.231). A good reliability of measurements of hepatic artery PSV and PI was demonstrated by intraclass correlation coefficient analysis (ICC 0.971 95% CI 0.963-0.977, p<0.001 and ICC 0.694 95% CI 0.596-0.772, p<0.001, respectively). CONCLUSIONS: Monochorionic pregnancies with TTTS are associated with lower HAV-ratios. This could be explained by an active HABR.

Proteomic analysis reveals stage-specific reprogramed metabolism for the primary breast cancer cell lines MGSO-3 and MACL-1.

Breast cancer is the most prevalent cancer in women worldwide. Its molecular subtypes are based on the presence/absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). MACL-1 and MGSO-3 are cell lines derived from primary tumor sites of patients diagnosed with luminal A subtype carcinoma (ER+/PR+/HER2-) and ductal carcinoma in situ (ER-/PR-/HER2+), respectively. However, these cell lines lost the expression of these markers over cell culturing, and both have triple-negative phenotypes (ER-/PR-/HER2-), which has the poorest prognosis. Here, we sought to study the proteome signature of MGSO-3 and MACL-1, comparing them with the epithelial cell line MCF-10A and the well-established metastatic-derived breast cancer cell line MDA-MB-231. Our results showed that proteins associated with the tricarboxylic acid cycle (TCA) and oxidative phosphorylation (OXPHOS) were upregulated in MGSO-3 and MACL-1 cells. These cell lines also showed upregulation of pro-apoptotic proteins when compared with MDA-MB-231. The molecular differences highlighted in this study may clarify the molecular basis behind cancer cells functioning and may reveal novel signatures across the breast cancer cell models.

SOCS2 expression in hematopoietic and non-hematopoietic cells during Trypanosoma cruzi infection: Correlation with immune response and cardiac dysfunction.

Chagas disease has a complex pathogenesis wherein the host immune response is essential for controlling its development. Suppressor of cytokine signaling(SOCS)2 is a crucial protein that regulates cytokine production. In this study, SOCS2 deficiency resulted in an initial imbalance of IL12- and IL-10-producing neutrophils and dendritic cells (DCs), which caused a long-lasting impact reducing inflammatory neutrophils and DCs, and tolerogenic DCs at the peak of acute disease. A reduced number of inflammatory and pro-resolving macrophages, and IL17A-producing CD4+ T cells, and increased lymphocyte apoptosis was found in SOCS2-deficient mice. Electrocardiogram analysis of chimeric mice showed that WT mice that received SOCS2 KO bone marrow transplantation presented increased heart dysfunction. Taken together, the results demonstrated that SOCS2 is a crucial regulator of the immune response during Trypanosoma cruzi infection, and suggest that a SOCS2 genetic polymorphism, or failure of its expression, may increase the susceptibility of cardiomyopathy development in Chagasic patients.

Correction: Reactive oxygen species and nitric oxide imbalances lead to in vivo and in vitro arrhythmogenic phenotype in acute phase of experimental Chagas disease.

[This corrects the article DOI: 10.1371/journal.ppat.1008379.].

Reactive oxygen species and nitric oxide imbalances lead to in vivo and in vitro arrhythmogenic phenotype in acute phase of experimental Chagas disease.

Chagas Disease (CD) is one of the leading causes of heart failure and sudden death in Latin America. Treatments with antioxidants have provided promising alternatives to ameliorate CD. However, the specific roles of major reactive oxygen species (ROS) sources, including NADPH-oxidase 2 (NOX2), mitochondrial-derived ROS and nitric oxide (NO) in the progression or resolution of CD are yet to be elucidated. We used C57BL/6 (WT) and a gp91PHOX knockout mice (PHOX-/-), lacking functional NOX2, to investigate the effects of ablation of NOX2-derived ROS production on the outcome of acute chagasic cardiomyopathy. Infected PHOX-/- cardiomyocytes displayed an overall pro-arrhythmic phenotype, notably with higher arrhythmia incidence on ECG that was followed by higher number of early afterdepolarizations (EAD) and 2.5-fold increase in action potential (AP) duration alternans, compared to AP from infected WT mice. Furthermore, infected PHOX-/- cardiomyocytes display increased diastolic [Ca2+], aberrant Ca2+ transient and reduced Ca2+ transient amplitude. Cardiomyocyte contraction is reduced in infected WT and PHOX-/- mice, to a similar extent. Nevertheless, only infected PHOX-/- isolated cardiomyocytes displayed significant increase in non-triggered extra contractions (appearing in ~75% of cells). Electro-mechanical remodeling of infected PHOX-/-cardiomyocytes is associated with increase in NO and mitochondria-derived ROS production. Notably, EADs, AP duration alternans and in vivo arrhythmias were reverted by pre-incubation with nitric oxide synthase inhibitor L-NAME. Overall our data show for the first time that lack of NOX2-derived ROS promoted a pro-arrhythmic phenotype in the heart, in which the crosstalk between ROS and NO could play an important role in regulating cardiomyocyte electro-mechanical function during acute CD. Future studies designed to evaluate the potential role of NOX2-derived ROS in the chronic phase of CD could open new and more specific therapeutic strategies to treat CD and prevent deaths due to heart complications.

Inhibition of calcium/calmodulin (Ca2+ /CaM)-Calcium/calmodulin-dependent protein kinase II (CaMKII) axis reduces in vitro and ex vivo arrhythmias in experimental Chagas disease.

Chagasic cardiomyopathy (CCC) is one of the main causes of heart failure and sudden death in Latin America. To date, there is no available medication to prevent or reverse the onset of cardiac symptoms. CCC occurs in a scenario of disrupted calcium dynamics and enhanced oxidative stress, which combined, may favor the hyper activation of calcium/calmodulin (Ca2+ /CaM)-calcium/calmodulin-dependent protein kinase II (CaMKII) (Ca2+ /CaM-CaMKII) pathway, which is fundamental for heart physiology and it is implicated in other cardiac diseases. Here, we evaluated the association between Ca2+ /CaM-CaMKII in the electro-mechanical (dys)function of the heart in the early stage of chronic experimental Trypanosoma cruzi infection. We observed that in vitro and ex vivo inhibition of Ca2+ /CaM-CaMKII reversed the arrhythmic profile of isolated hearts and isolated left-ventricles cardiomyocytes. The benefits of the limited Ca2+ /CaM-CaMKII activation to cardiomyocytes' electrical properties are partially related to the restoration of Ca2+ dynamics in a damaged cellular environment created after T. cruzi infection. Moreover, Ca2+ /CaM-CaMKII inhibition prevented the onset of arrhythmic contractions on isolated heart preparations of chagasic mice and restored the responsiveness to the increase in the left-ventricle pre-load. Taken together, our data provide the first experimental evidence for the potential of targeting Ca2+ /CaM-CaMKII pathway as a novel therapeutic target to treat CCC.

Unraveling the Cardiac Effects Induced by Carvacrol in Spontaneously Hypertensive Rats: Involvement of Transient Receptor Potential Melastatin Subfamily 4 and 7 Channels.

ABSTRACT: Accumulating evidence indicates that transient receptor potential (TRP) channels are involved in the pathophysiological process in the heart, and monoterpenes, such as carvacrol, are able to modulate these channels activity. In this article, our purpose was to evaluate the direct cardiac effect of carvacrol on the contractility of cardiomyocytes and isolated right atria from spontaneously hypertensive and Wistar Kyoto rats. In this way, in vitro experiments were used to evaluate the ventricular cardiomyocytes contractility and the Ca2+ transient measuring, in addition to heart rhythm in the right atria. The role of TRPM channels in carvacrol-mediated cardiac activities was also investigated. The results demonstrated that carvacrol induced a significant reduction in ventricular cell contractility, without changes in transient Ca2+. In addition, carvacrol promoted a significant negative chronotropic response in spontaneously hypertensive and Wistar Kyoto rats' atria. Selective blockage of TRPM channels suggests the involvement of TRP melastatin subfamily 2 (TRPM2), TRPM4, and TRPM7 in the carvacrol-mediated cardiac effects. In silico studies were conducted to further investigate the putative role of TRPM4 in carvacrol-mediated cardiac action. FTMap underscores a conserved pocket in both TRPM4 and TRPM7, revealing a potential carvacrol binding site, and morphological similarity analysis demonstrated that carvacrol shares a more than 85% similarity to 9-phenanthrol. Taken together, these results suggest that carvacrol has direct cardiac actions, leading to reduced cellular contractility and inducing a negative chronotropic effect, which may be related to TRPM7 and TRPM4 modulation.

Nasal bone in fetal aneuploidy risk assessment: are they independent markers in the first and second trimesters?

OBJECTIVES: In the mid-trimester ultrasound, nasal bone (NB) length can be used to correct the a priori risk for trisomy 21. Our study aims to evaluate if there is a correlation between an absent NB in the first trimester and a hypoplastic NB in the second trimester. METHODS: Our two year retrospective analysis of data derived from routine clinical practice. Single euploid fetuses were included. The NB was assessed in both trimesters according to international guidelines and transformed into categorical variables. Logistic regression was performed in order to accomplish our main objective. RESULTS: From the 759 normal pregnancies included, 45 (5.93%) had abnormal NB in the first trimester and 23 (3%) in the second trimester. Eleven cases (47.8%) of the abnormal NB in the second trimester were abnormal in the 11-14 weeks scan. After the diagnosis of an absent NB in the first trimester the odds ratio (OR) for a hypoplastic NB in the second trimester is 18.926 (7.791-45.977; p-value <0.01). CONCLUSIONS: Our data suggest a strong association between the NB in the first and in the second trimester in normal euploid fetuses. This is important information to consider when counseling patients on the basis of this ultrasound marker.

First trimester examination of fetal anatomy: clinical practice guideline by the World Association of Perinatal Medicine (WAPM) and the Perinatal Medicine Foundation (PMF).

This recommendation document follows the mission of the World Association of Perinatal Medicine in collaboration with the Perinatal Medicine Foundation. We aim to bring together groups and individuals throughout the world for precise standardization to implement the ultrasound evaluation of the fetus in the first trimester of pregnancy and improve the early detection of anomalies and the clinical management of the pregnancy. The aim is to present a document that includes statements and recommendations on the standard evaluation of the fetal anatomy in the first trimester, based on quality evidence in the peer-reviewed literature as well as the experience of perinatal experts around the world.

Role of formyl peptide receptor 2 (FPR2) in modulating immune response and heart inflammation in an experimental model of acute and chronic Chagas disease.

Chagas disease is an important disease of the heart. Lipoxins have important regulatory functions in host immune response (IR). Herein, we examined whether the receptor for lipoxin A4, the formyl peptide receptor (FPR) 2, had an effect on Trypanosoma cruzi infection. In vitro, FPR2 deficiency or inhibition improved the activity of macrophages against T. cruzi. In vivo, during the acute phase, the absence of FPR2 reduced parasitemia and increased type 2 macrophages, type 2 neutrophils, and IL-10-producing dendritic cells. Moreover, the acquired IR was characterized by greater proportions of Th1/Th2/Treg, and IFNγ-producing CD8+T cells, and reductions in Th17 and IL-17-producing CD8+T cells. However, during the chronic phase, FPR2 deficient mice presented and increased inflammatory profile regarding innate and acquired IR cells (Th1/IFN-γ-producing CD8+T cells). Notably, FPR2 deficiency resulted in increased myocarditis and impaired heart function. Collectively, our data suggested that FPR2 is important for the orchestration of IR and prevention of severe T. cruzi-induced disease.

Biocidal Activity of a Nanoemulsion Containing Essential Oil from Protium heptaphyllum Resin against Aedes aegypti (Diptera: Culicidae).

This work aimed to prepare a nanoemulsion containing the essential oil of the Protium heptaphyllum resin and evaluate its biocidal activities against the different stages of development of the Aedes aegypti mosquito. Ovicide, pupicide, adulticide and repellency assays were performed. The main constituents were p-cymene (27.70%) and α-pinene (22.31%). The developed nanoemulsion showed kinetic stability and monomodal distribution at a hydrophilic-lipophilic balance of 14 with a droplet size of 115.56 ± 1.68 nn and a zeta potential of -29.63 ± 3.46 mV. The nanoemulsion showed insecticidal action with LC50 0.404 µg·mL-1 for the ovicidal effect. In the pupicidal test, at the concentration of 160 µg·mL-1, 100% mortality was reached after 24 h. For adulticidal activity, a diagnostic concentration of 200 µg·mL-1 (120 min) was determined. In the repellency test, a concentration of 200 µg·mL-1 during the 180 min of the test showed a protection index of 77.67%. In conclusion, the nanobiotechnological product derived from the essential oil of P. heptaphyllum resin can be considered as a promising colloid that can be used to control infectious disease vectors through a wide range of possible modes of applications, probably as this bioactive delivery system may allow the optimal effect of the P. heptaphyllum terpenes in aqueous media and may also induce satisfactory delivery to air interfaces.

Diminazene aceturate (DIZE) has cellular and in vivo antiarrhythmic effects.

Diminazene aceturate (DIZE) is an anti-protozoan compound that has been previously reported to increase the activity of the angiotensin-converting enzyme 2 (ACE2) and thus increase Angiotensin-(1-7) production, leading to cardioprotection against post-myocardial infarction dysfunction and structural remodelling. Moreover, DIZE is able to ameliorate morpho-functional changes after myocardial infarction by enhancing ACE2 activity, thus increasing Angiotensin-(1-7) production (a benefic peptide of the renin-angiotensin system). However, despite the improvement in cardiac function/structure, little is known about DIZE effects on arrhythmia suppression, contraction/excitable aspects of the heart and importantly its mechanisms of action. Thus, our aim was to test the acute effect of DIZE cardioprotection at the specific level of potential antiarrhythmic effects and modulation in excitation-contraction coupling. For this, we performed in vitro and in vivo techniques for arrhythmia induction followed by an acute administration of DIZE. For the first time, we described that DIZE can reduce arrhythmias which is explained by modulation of cardiomyocyte contraction and excitability. Such effects were independent of Mas receptor and nitric oxide release. Development of a new DIZE-based approach to ameliorate myocardial contractile and electrophysiological dysfunction requires further investigation; however, DIZE may provide the basis for a future beneficial therapy to post-myocardial infarction patients.

Initial Experience of Superb Microvascular Imaging for Key Cardiac Views in Foetal Assessment before 15 Weeks Gestation.

BACKGROUND: In the first trimester, ultrasound confirmation of normal or abnormal cardiac anatomy is difficult. B-mode and colour flow Doppler (CFD) are used to assess the foetal heart. Superb microvascular imaging (SMI) can visualise blood flow within the heart and vessels in early gestation. OBJECTIVE: We report an initial experience of SMI for visualisation of normal and abnormal cardiac anatomy in the first trimester. METHODS: Transabdominal foetal echocardiography was performed between 11 + 6 and 14 + 3 weeks (Aplio 500 US system, Toshiba Medical Systems, Tokyo, Japan) from January 2017 to December 2017. All scans were performed at a tertiary foetal cardiology unit. To assess the potential utility of the technique for early gestation screening, normal scans were reviewed by foetal medicine trainees with respect to the B-mode, CFD and SMI. Three key views were selected to compare modalities: the 4-chamber view, outflow tracts and the 3-vessel and trachea view (VTV). Visualisation rates of key echocardiographic features of significant cardiac abnormalities by SMI were reviewed. RESULTS: Fifty-five normal echocardiograms and 34 cardiac abnormalities were included. In the normal heart, when B-mode, CFD and SMI were assessed separately, SMI had the highest rate of visualisation of 4-chamber, outflow tracts and 3-VTV (93, 85 and 83%, respectively). Intra-observer reliability was moderate for SMI of the 3 standard views (kappa 1, 0.64 and 0.64); inter-observer for 4-chamber and outflow tract views was moderate (kappa 0.64 and 0.77). In 29/34 abnormal cases, SMI showed key features, enhancing greyscale visualisation. CONCLUSION: SMI has potential to become a useful, complementary modality for early foetal echocardiography. Further prospective studies are warranted to establish the place of the technique in assessment of the first trimester foetal heart.

Larvicide Activity on Aedes aegypti of Essential Oil Nanoemulsion from the Protium heptaphyllum Resin.

The aim of this work was to prepare a nanoemulsion containing the essential oil of Protium heptaphyllum resin and to evaluate the larvicidal activity and the residual larvicidal effect against Aedes aegypti. The essential oil was identified by gas chromatography coupled to a mass spectrometer, and the nanoemulsions were prepared using a low-energy method and characterized by photon correlation spectroscopy. The results indicated the major constituents as p-cimene (27.70%) and α-Pinene (22.31%). Nanoemulsions had kinetic stability and a monomodal distribution in a hydrophilic-lipophilic balance of 14 with particle diameters of 115.56 ± 1.68 nn and zeta potential of -29.63 ± 3.46 mV. The nanoemulsion showed larvicidal action with LC50 = 2.91 µg∙mL-1 and residual larvicidal effect for 72 h after application to A. aegypti larvae. Consequently, the nanobiotechnological product derived from the essential oil of P. heptaphyllum resin could be used against infectious disease vectors.

Hydrogen peroxide and nitric oxide induce anticontractile effect of perivascular adipose tissue via renin angiotensin system activation.

The perivascular adipose tissue (PVAT) is located around the adventitia, composed primarily by adipocytes, stromal cells, leukocytes, fibroblasts and capillaries. It is well described that PVAT is an important modulator of the vascular tone being considered a biologically active tissue, releasing both vasoconstrictor and vasodilators factors. The literature shows that the anti-contractile effect induced by PVAT may be due to activation of the renin-angiotensin system (RAS). AIM: Investigate whether the renin-angiotensin system participates in the effect exerted by perivascular adipose tissue on the vascular tone. METHODS AND RESULTS: For this study we used thoracic aorta from Balb/c mice and performed vascular reactivity, nitric oxide and hydrogen peroxide quantification using selective probes and fluorescence microscopy, immunofluorescence to locate receptors and enzymes involved in this response. Our results demonstrated that perivascular adipose tissue induces an anti-contractile effect in endothelium-independent manner and involves Mas and AT2 receptors participation with subsequent PI3K/Akt pathway activation. This pathway culminated with nitric oxide and hydrogen peroxide production by neuronal nitric oxide synthase, being hydrogen peroxide most relevant for the anti-contractile effect of perivascular adipose tissue. CONCLUSION: For the first time in the literature, our results show the presence of Mas and AT2 receptors, as well as, nitric oxide synthase on perivascular adipose tissue. Furthermore, our results show the involvement of Mas and AT2 receptors and consequently nitric oxide synthase activation in the anti-contractile effect exerted by perivascular adipose tissue.

d-Limonene Ameliorates Myocardial Infarction Injury by Reducing Reactive Oxygen Species and Cell Apoptosis in a Murine Model.

Myocardial infarction (MI) leads to high mortality, and pharmacological or percutaneous primary interventions do not significantly inhibit ischemia/reperfusion injuries, particularly those caused by oxidative stress. Recently, research groups have evaluated several naturally occurring antioxidant compounds for possible use as therapeutic alternatives to traditional treatments. Studies have demonstrated that d-limonene (DL), a monoterpene of citrus fruits, possesses antioxidant and cardiovascular properties. Thus, this work sought to elucidate the mechanisms of protection of DL in an isoproterenol-induced murine MI model. It was observed that DL (10 µmol) attenuated 40% of the ST elevation, reduced the infarct area, prevented histological alterations, abolished completely oxidative stress damage, restored superoxide dismutase activity, and suppressed pro-apoptotic enzymes. In conclusion, the present study demonstrated that DL produces cardioprotective effects from isoproterenol-induced myocardial infarction in Swiss mice through suppression of apoptosis.

Absence of suppressor of cytokine signaling 2 turns cardiomyocytes unresponsive to LIF-dependent increases in Ca2+ levels.

Little is known regarding the role of suppressor of cytokine signaling (SOCS) in the control of cytokine signaling in cardiomyocytes. We investigated the consequences of SOCS2 ablation for leukemia inhibitory factor (LIF)-induced enhancement of intracellular Ca2+ ([Ca2+]i) transient by performing experiments with cardiomyocytes from SOCS2-knockout (ko) mice. Similar levels of SOCS3 transcripts were seen in cardiomyocytes from wild-type and SOCS2-ko mice, while SOCS1 mRNA was reduced in SOCS2-ko. Immunoprecipitation experiments showed increased SOCS3 association with gp130 receptor in SOCS2-ko myocytes. Measurements of Ca2+ in wild-type myocytes exposed to LIF showed a significant increase in the magnitude of the Ca2+ transient. This change was absent in LIF-treated SOCS2-ko cells. LIF activation of ERK and STAT3 was observed in both wild-type and SOCS2-ko cells, indicating that in SOCS2-ko, LIF receptors were functional, despite the lack of effect in the Ca2+ transient. In wild-type cells, LIF-induced increase in [Ca2+]i and phospholamban Thr17 [PLN(Thr17)] phosphorylation was inhibited by KN-93, indicating a role for CaMKII in LIF-induced Ca2+ raise. LIF-induced phosphorylation of PLN(Thr17) was abrogated in SOCS2-ko myocytes. In wild-type cardiomyocytes, LIF treatment increased L-type Ca2+ current (ICa,L), a key activator of CaMKII in response to LIF. Conversely, SOCS2-ko myocytes failed to activate ICa,L in response to LIF, providing a rationale for the lack of LIF effect on Ca2+ transient. Our data show that absence of SOCS2 turns cardiomyocytes unresponsive to LIF-induced [Ca2+] raise, indicating that endogenous levels of SOCS2 are crucial for full activation of LIF signaling in the heart.