Heart Muscle Cells Research Articles

From the Literature

From the Literature

Select α-arrestins control cell-surface abundance of the mammalian Kir2.1 potassium channel in a yeast model

Protein composition at the plasma membrane is tightly regulated, with rapid protein internalization and selective targeting to the cell surface occurring in response to environmental changes. For example, ion channels are dynamically relocalized to or from the plasma membrane in response to physiological alterations, allowing cells and organisms to maintain osmotic and salt homeostasis. To identify additional factors that regulate the selective trafficking of a specific ion channel, we used a yeast model for a mammalian potassium channel, the K+ inward rectifying channel Kir2.1. Kir2.1 maintains potassium homeostasis in heart muscle cells, and Kir2.1 defects lead to human disease. By examining the ability of Kir2.1 to rescue the growth of yeast cells lacking endogenous potassium channels, we discovered that specific α-arrestins regulate Kir2.1 localization. Specifically, we found that the Ldb19/Art1, Aly1/Art6, and Aly2/Art3 α-arrestin adaptor proteins promote Kir2.1 trafficking to the cell surface, increase Kir2.1 activity at the plasma membrane, and raise intracellular potassium levels. To better quantify the intracellular and cell-surface populations of Kir2.1, we created fluorogen-activating protein fusions and for the first time used this technique to measure the cell-surface residency of a plasma membrane protein in yeast. Our experiments revealed that two α-arrestin effectors also control Kir2.1 localization. In particular, both the Rsp5 ubiquitin ligase and the protein phosphatase calcineurin facilitated the α-arrestin-mediated trafficking of Kir2.1. Together, our findings implicate α-arrestins in regulating an additional class of plasma membrane proteins and establish a new tool for dissecting the trafficking itinerary of any membrane protein in yeast.

Moderate preterm birth affects right ventricular structure and function and pulmonary artery blood flow in adult sheep.

Preterm birth occurs when the heart muscle is immature and ill-prepared for the changes in heart and lung function at birth. MRI imaging studies show differences in the growth and function of the heart of young adults born preterm, with the effects more pronounced in the right ventricle. The findings of this study, conducted in sheep, showed that following moderate preterm birth the right ventricular wall was thinner in adulthood, with a reduction in the number and size of the heart muscle cells; in addition, there was impaired blood flow in the main artery leading from the right ventricle to the lungs. The findings indicate that being born only a few weeks early adversely affects the cellular structure of the right ventricle and blood flow to the lungs in adulthood. The reduced number of heart muscle cells has the potential to deleteriously affect right ventricular growth potential and function. Preterm birth prematurely exposes the immature heart to the haemodynamic transition at birth, which has the potential to induce abnormal cardiac remodelling. Magnetic resonance imaging studies in young adults born preterm have shown abnormalities in the gross structure of the ventricles (particularly the right ventricle; RV), but the cellular basis of these alterations is unknown. The aim of this study, conducted in sheep, was to determine the effect of moderate preterm birth on RV cellular structure and function in early adulthood. Male singleton lambs were delivered moderately preterm (132±1days; n=7) or at term (147±1days; n=7). At 14.5months of age, intra-arterial blood pressure and heart rate were measured. Pulmonary artery diameter and peak systolic blood flow were determined using ultrasound imaging, and RV stroke volume and output calculated. Cardiomyocyte number, size, nuclearity and levels of cardiac fibrosis were subsequently assessed in perfusion-fixed hearts using image analysis and stereological methods. Blood pressure (systolic, diastolic and mean), heart rate, levels of myocardial fibrosis and RV stroke volume and output were not different between groups. There was, however, a significant reduction in RV wall thickness in preterm sheep, and this was accompanied by a significant reduction in peak systolic blood flow in the pulmonary artery and in RV cardiomyocyte number. Cellular changes in the RV wall and reduced pulmonary artery blood flow following preterm birth have the potential to adversely affect cardiac and respiratory haemodynamics, especially when the cardiovascular system is physiologically or pathologically challenged.

CURRENT PHARMACOLOGICAL STATUS OF CARDIOPROTECTIVE PLANTS AGAINST ISOPROTERENOL INDUCED MYOCARDIAL INFARCTION

Objective: Cardiovascular diseases are the major cause of morbidity and mortality in the modern era. Myocardial infarction is a condition where there is a significant decrease or block in the blood (oxygen) supply to the part of heart, leading to degeneration of a portion of the myocardium which triggers a cascade of cellular, inflammatory and biochemical events, leading eventually to the irreversible death (necrosis) of heart muscle cells. Various therapeutic interventions, including lifestyle modification, pharmacological treatment options, and surgical techniques are available. The present review focus on the plants that have been evaluated for cardioprotective activity against isoproterenol-induced myocardial infarction.Method: The current status of Cardioprotective plants was obtained from a literature search of electronic databases such as Google Scholar, Pubmed and Scopus up to 2017 for publications on medicinal plants used against isoproterenol-induced myocardial infarction. Isoproterenol, Isoprenaline, myocardial infarction, cardioprotective were used as keywords for the searching.Result: A total of 117 different plant parts and their extracts have till now been published to possess cardioprotection against isoproterenol-induced myocardial infarction. Isoproterenol a beta-adrenergic receptors agonist causes severe stress in myocardium resulting in the infarct-like lesion and produced cardiotoxic effects by elevating the levels of cardiac biomarkers and causing changes in ECG. Plant-based medicines with their antioxidant, antiapoptotic, antihyperlipidemic, platelet antiaggregatory, anti-lipid peroxidation property provide substantial evidence for the management of Ischemia.Conclusion: This review, therefore, provides a useful resource to enable a thorough assessment of the profile of plants that have cardioprotective activity against isoproterenol-induced myocardial infarction.

Identification of immunohistochemical localization of irisin in the dwarf hamster (Phodopus roborovskii) tissues.

Irisin is mainly secreted by heart and skeletal muscle cells. It is an exercise-induced protein that converts white adipose tissue to brown. Increased irisin expression was lead to weight loss and improved glucose tolerance. We investigated irisin immunoreactivity in various tissues of the dwarf hamsters (Phodopus roborovskii). Tissues were processed, embedded in paraffin, sectioned at 5μm and stained immunohistochemically for irisin. In the retina, irisin was found almost all layers, except outer nuclear layer. Also, irisin immunoreactivity was observed in the skin, cornea, striated muscle, parotid gland, tongue, oesophagus, stomach and small intestine. The findings from this study support the notion that skeletal muscle is not the primary source of irisin.

Cardiac enzymes activity and lactate concentration in the blood of sport horses at myocardial dystrophy

The article presents the results of research on the activity of cardiac specific enzymes and the concentration of lactate in the blood of sport horses for myocardial dystrophy of physical activity. Materials for researches were horses, used in the classical forms of equestrian sport of Ukrainian riding (n = 20), Hanoverian (n = 15) and Westphalian (n = 15) breeds. The average age of horses was 8.4 ± 0.71 years (3.5–16.0 g.), weight – 479.4 ± 8.54 kg (350–605 kg). Studies were conducted immediately before and immediately after exercise. The duration of regular training of average intensity was 1 hour: step 5 min; roaring lynx 10 minutes; step 5 min; training lynx 10 minutes; step 10 min; gallop with a transition to a step of 10 minutes; step 10 min. Blood samples from horses were taken from a jugular vein in a test tube without an anticoagulant (10 ml; Vacutest, Italy) and an anticoagulant (EDTA-K, 2.0 ml; Sarstedt, Germany). Diseases of the heart muscle are accompanied by the release of substances released from damaged cardiomyocytes, in particular, creatine kinase (CK), lactate dehydrogenase (LDH), myoglobin. It has been established that the key to the pathogenesis of myocardial dystrophy in sport horses is the discrepancy between costs and energy recovery in the functioning structures of the heart muscle due to excessive cardiac load and significant increase in energy costs, as well as a disturbance in the balance of the electrolytes. Hyperlactatemia that occurs in horses during exercise causes changes in the permeability of cardiomyocytes and exit enzymes in the blood and can play a key role in the pathogenesis of myocardial dystrophy. Іn sporting horses, after activity in blood serum, activity of AST and LDH increases in blood serum, a tendency to increase activity of creatine kinase (CК) is observed. The cardiac isoenzyme CK (CK‒MB) was detected by a specific marker of myocardial dystrophy in sport horses, since its activity was likely to increase in the blood of all experimental groups of animals. A less specific marker of myocardial damage was the activity of hydroxybutyrate dehydrogenase (LDH‒1) in the blood, since the probable difference was established only in the Westphalian horses. Investigating the activity of AST, CK and CK-MB in horses can serve for differential diagnosis of rhabdomyolysis syndrome and damage to heart muscle cells, in particular for myocardial dystrophy.

α-Catenin-dependent cytoskeletal tension controls Yap activity in the heart.

Shortly after birth, muscle cells of the mammalian heart lose their ability to divide. At the same time, the N-cadherin/catenin cell adhesion complex accumulates at the cell termini, creating a specialized type of cell-cell contact called the intercalated disc (ICD). To investigate the relationship between ICD maturation and proliferation, αE-catenin (Ctnna1) and αT-catenin (Ctnna3) genes were deleted to generate cardiac-specific α-catenin double knockout (DKO) mice. DKO mice exhibited aberrant N-cadherin expression, mislocalized actomyosin activity and increased cardiomyocyte proliferation that was dependent on Yap activity. To assess effects on tension, cardiomyocytes were cultured on deformable polyacrylamide hydrogels of varying stiffness. When grown on a stiff substrate, DKO cardiomyocytes exhibited increased cell spreading, nuclear Yap and proliferation. A low dose of either a myosin or RhoA inhibitor was sufficient to block Yap accumulation in the nucleus. Finally, activation of RhoA was sufficient to increase nuclear Yap in wild-type cardiomyocytes. These data demonstrate that α-catenins regulate ICD maturation and actomyosin contractility, which, in turn, control Yap subcellular localization, thus providing an explanation for the loss of proliferative capacity in the newborn mammalian heart.

In This Issue

HomeCirculation ResearchVol. 122, No. 3In This Issue Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBIn This Issue Ruth Williams Ruth WilliamsRuth Williams Search for more papers by this author Originally published2 Feb 2018https://doi.org/10.1161/RES.0000000000000197Circulation Research. 2018;122:385Open Software to Quantify Cardiac Contraction (p e5)Sala et al create MUSCLEMOTION, an open-source software for quantifying contractions in both heart muscle cells and tissues.Download figureDownload PowerPointMeasurement and analysis of cardiac contractility are of high importance in studying muscle function, assessing disease phenotypes, and evaluating drug toxicity. Unlike electrophysiological measurements, for which there are well-established and standardized techniques applicable to a range of samples, the techniques for measuring myocardial contractions tend to be sample-specific, not easily comparable, and require specialized expertise. Sala and colleagues have now developed a novel software that can quantify contractions in movies of specimens as diverse as single heart cells, cultured cardiac myocytes, 3D cardiac organoids, and even living Zebrafish hearts. They tested the ability of their software, called MUSCLEMOTION, to detect drug-induced and disease-related contraction differences in a variety of samples and showed that the performance of the software was comparable to various gold-standard techniques tailored to those specific samples. By making MUSCLEMOTION user-friendly and freely accessible, the authors hope to facilitate comparisons of contraction data, not just between samples, but between laboratories as well, thereby facilitating data replication and reproducibility.64 Novel Genetic Loci for Coronary Artery Disease (p 433)Van der Harst and Verweij provide evidence for an omnigenic model of coronary artery disease.Download figureDownload PowerPointCoronary artery disease (CAD) is a multifactorial condition with contributions from both genetic and environmental factors. It has been associated with a number of genetic loci, yet linking these to potential pathological pathways remains difficult. Van der Harst and Verweij have now carried out the largest GWAS (genome-wide association study) to date. Examining nearly 8 million single nucleotide polymorphisms (SNPs) in a total of 122 733 CAD patient samples, they identified 64 novel CAD-associated loci. These candidate genes, however, are involved in such broad biological functions and expressed in such diverse tissues that the contribution of genetic factors appears to be even more complicated than first thought, as many loci have no obvious link to CAD. Based on these findings, the authors suggest that the model of CAD as a polygenic disease—one caused by multiple genes affecting a handful of key pathways—may be incorrect. Instead, they surmise that the results point to an omnigenic model—whereby the link between many SNPs and CAD may be one of interconnectedness of gene-regulatory mechanisms. If so, determining cell-specific networks of gene expression may be the best route to understanding CAD pathology.Long-Term MRI Follow-Up of MVO After Cell Therapy (p 479)Traverse et al report the final 2-year results of the stem cell TIME trial.Download figureDownload PowerPointStem cell therapies are under investigation for their potential to promote cardiac tissue repair after myocardial infarction (MI). Because changes to the myocardium following reperfusion could influence cell engraftment and survival, the timing of cell delivery was examined in the TIME trial (Timing In Myocardial Infarction Evaluation), which compared delivery of cells on day 3 with day 7 following MI in 120 patients. At 6 months, the results indicated that cells delivered at either time point offered no benefits to patients. And 2 years later, these results remain the same. However, the study has also provided one of the largest MRI datasets of patients following MI. By analyzing these data, Traverse and colleagues show that patients who had microvascular obstructions at baseline have poorer outcomes—larger infarct size, more adverse left ventricle remodeling, reduced recovery of ventricle function, and greater likelihood of requiring an implantation device. From these findings, the team suggests that the presence of microvascular obstruction may be a powerful predictor of subsequent left ventricle failure, and that microvascular dysfunction identifies the most at-risk patients. Previous Back to top Next FiguresReferencesRelatedDetails February 2, 2018Vol 122, Issue 3 Advertisement Article InformationMetrics © 2018 American Heart Association, Inc.https://doi.org/10.1161/RES.0000000000000197 Originally publishedFebruary 2, 2018 PDF download Advertisement

Transaminase enzymes and lipid profiles and histological changes in Wistar rats after administration of bintangur (Calophyllum soulattri) leaves ethanolic extract

Fajriaty I, Apridamayanti P, Rahmawani SP, Abdurrachman. 2018. Transaminase enzymes and lipid profiles and histological changes in Wistar rats after administration of bintangur (Calophyllum soulattri) leaves ethanolic extract. Nusantara Bioscience 10: 27- 35. Bintangur (Calophyllum soulattri Burm. F) can be found in West Kalimantan and traditionally used as a medicine for treatment of wounds, inflammation, and rheumatism. Bintangur contains terpene derivatives, xanthones, coumarins, steroid derivatives, flavonoid and also saponins. The present study was conducted to determine the in vivo effect of oral administration of bintangur leaves ethanolic extract (BLEE) on transaminase and lipid profiles and histological changes in experimental rats. Eighty-four Wistar rats were divided into six groups; each group consisted of seven male and seven female rats. The first group was applied with CMC-Na 1% as a control. The second, third, and fourth group were applied with 100 mg kg-1 BW, 400 mg kg-1 BW, 1000 mg kg-1 BW dose of BLEE respectively. The fifth and sixth group were the satellite for assessment of reversibility, persistence or delayed effects. The animals were given extract once daily for 28 days, while for the satellite groups still observed until 14 days. At the end of the study, all rats were sacrificed, and the blood and organs were collected for biochemical and histological examination. The result showed that BLEE increased transaminase profile, ALT, and AST, with the highest increase in 400 mg kg-1 BW dose. But a significant increase (p<0.05) only found in AST profile of 400 mg kg-1 BW dose in female rats. In lipid profile, BLEE did not affect cholesterol total, but caused significant decrease (p<0.05) in triglyceride profile of 1000 mg kg-1 BW dose in male and female rats. In the histological assessment, obvious histological changes were observed in liver and heart. There had necrosis of hepatocytes cells of male and female rats with obvious changes in 1000 mg kg-1 BW dose and congestion of central vein of male rats in 400 mg kg-1 BW dose and 1000 mg kg-1 BW dose. In heart muscle fibers showed an irregular structure in 1000 mg kg-1 BW dose of female rats. While observation of spleen showed no harmful changes in all groups. The conclusion of this study showed BLEE increase transaminase profile and some damaging effect on the liver and heart organ of Wistar rat but should be considered as an herbal medicine with potential effect as antihypertriglyceridemia.

IMMUNOHISTOCHEMICAL EVALUATION OF VASOENDOTHELIAL GROWTH FACTOR RECEPTOR-2 (VEGFR2) EXPRESSION IN RAT CARDIOMYOCYTES UNDER DOXORUBICIN AND BETULONIC ACID AMIDE ADMINISTRATION

The aim of the study is to perform an immunohistochemical analysis of the expression of the vascular endothelial growth factor receptor 2 (VEGFR2) in the myocardium of Wistar rats in doxorubicin-induced cardiomyopathy and the administration of betulonic acid amide as an agent with a polytarget effect in comparison with the severity of destructive processes in heart muscle cells. Material and methods. Wistar male rats (total 51 animals) were used in the work with isolated and combined administration of a single sublethal dose of doxorubicin (7 mg/kg) and course administration of betulonic acid amide at doses of 50 mg/kg/day and 100 mg/kg/day for 3 and 14 days. Immunohistochemical evaluation of VEGFR2 expression in the myocardium was carried out with the calculation of the index of VEGFR2-positive cardiomyocytes; the volume density of cardiomyocytes with lytic changes was estimated using stereological analysis. Results and discussion. A single administration of doxorubicin (at a dose of 7 mg/kg) caused destructive changes in cardiomyocytes and hemodynamic disorders in myocardium, which increased with the duration of the experiment (14 days). The complex of the revealed structural and metabolic lesions reflected the development of regenerative-plastic insufficiency of cardiomyocytes, which is the basis of cardiac insufficiency in anthracycline cardiomyopathy. Morphological changes in the myocardium with isolated administration of betulonic acid amide were largely determined by the dose used. At a dose of 100 mg/kg, myocardial changes were similar in severity with doxorubicin-induced changes. Combined use of doxorubicin and betulonic acid amide revealed the most significant structural damage of the myocardium. It was shown that the increase in the volume density of lytic altered cardiomyocytes correlated with a significant increase in VEGFR2 expression (correlation coefficient varied from 0.620 to 0.980).

Hair Follicle-Associated Pluripotent (HAP) Stem Cells in Gelfoam® Histoculture for Use in Spinal Cord Repair.

The stem cell marker, nestin, is expressed in the hair follicle, both in cells in the bulge area (BA) and the dermal papilla (DP). Nestin-expressinghair follicle-associated-pluripotent (HAP)stem cells of both the BA and DP have been previously shown to be able to form neurons, heart muscle cells, and other non-follicle cell types. The ability of the nestin-expressing HAP stem cells from the BA and DP to repair spinal cord injury was compared. Nestin-expressing HAP stem cells from both the BA and DP grew very well on Gelfoam®. The HAP stem cells attached to the Gelfoam® within 1h. They grew along the grids of the Gelfoam® during the first 2 or 3days. Later they spread into the Gelfoam®. After transplantation of Gelfoam® cultures of nestin-expressing BA or DP HAP stem cells into the injured spinal cord (including the Gelfoam®) nestin-expressing BA and DP cells were observed to be viable over 100days post-surgery. Hematoxylin and eosin (H&E) staining showed connections between the transplanted cells and the host spine tissue. Immunohistochemistry showed many Tuj1-, Isl 1/2, and EN1-positive cells and nerve fibers in the transplanted area of the spinal cord after BA Gelfoam® or DP Gelfoam® cultures were transplanted to the spine. The spinal cord of micewas injuredto effect hind-limb paralysis. Twenty-eight days after transplantation with BA or DPHAP stem cells on Gelfoam® to the injured area of the spine, the mice recoverednormal locomotion.

The Evaluation of Oleic Acid in the Prevention of Lipotoxicity Induced by Palmitic Acid in Rat Cultured Cardiomyocytes

Introduction: In a variety of experimental systems, saturated and unsaturated fatty acids differ significantly in their contributions to lipotoxicity. It was reported that oleic acid prevented the lipotoxicity in rat hepatocytes. The objective of the present experiment was to evaluate the effects of oleic acid on the induced lipotoxicity by palmitic acid in cultured cells of rat heart muscle. Materials & methods: Rat ventricular heart muscle cells were isolated and seeded into 24-well-plates. Cells were treated with one dose of palmitic acid (0.5 mmol/L), oleic acid (0.5 mmol/L), palmitic + oleic acid (0.5 mmol/L + 0.5 mmol/L) or left as control. Triacylglycerol (TAG), diacylglycerol (DAG), DNA fragmentation and percent of viability were measured at 24, 48 hoursafter adding fatty acids. Findings: Result showed that when oleic acid co-administrated with palmitic it would decrease DAG (P greater-than 0.05) and DNA fragmentation (P less-than 0.05) and increase TAG (P less-than 0.05) and viability (P less-than 0.05) in comparison with palmitic alone. Discussion & conclusions: In conclusion, oleic acid would improve the lipotoxicity indices of palmitic acid in primary adult rat cardiomyocytes culture.

Chronic ethanol increases calcium/calmodulin-dependent protein kinaseIIδ gene expression and decreases monoamine oxidase amount in rat heart muscles: Rescue effect of Zingiber officinale (ginger) extract.

Objective:Association between chronic alcohol intake and cardiac abnormality is well known; however, the precise underlying molecular mediators involved in ethanol-induced heart abnormalities remain elusive. This study investigated the effect of chronic ethanol exposure on calcium/calmodulin-dependent protein kinase IIδ (CaMKIIδ) gene expression and monoamine oxidase (MAO) levels and histological changes in rat heart. It was also planned to find out whether Zingiber officinale (ginger) extract mitigated the abnormalities induced by ethanol in rat heart.Methods:Male wistar rats were divided into three groups of eight animals each: control, ethanol, and ginger extract treated-ethanol (GETE) groups.Results:After 6 weeks of treatment, the results revealed a significant increase in CaMKIIδtotal and isoforms δ2 and δ3 of CaMKIIδ gene expression as well as a significant decrease in the MAO levels in the ethanol group compared to that in the control group. Moreover, compared to the control group, the ethanol group showed histological changes, such as fibrosis, heart muscle cells proliferation, myocyte hypertrophy, vacuolization, and focal lymphocytic infiltration. Consumption of ginger extract along with ethanol ameliorated CaMKIIδtotal. In addition, compared to the ethanol group, isoforms gene expression changed and increased the reduced MAO levels and mitigated heart structural changes.Conclusion:These findings indicate that ethanol-induced heart abnormalities may, in part, be associated with Ca2+ homeostasis changes mediated by overexpression of CaMKIIδ gene and the decrease of MAO levels and that these effects can be alleviated by using ginger extract as an antioxidant and anti-inflammatory agent.

Beating Heart Cells from Hair-Follicle-Associated Pluripotent (HAP) Stem Cells.

The neural stem-cell marker nestin is expressed in hair follicle stem cells located in the bulge area which are termed hair-follicle-associated pluripotent (HAP) stem cells. HAP stem cells can differentiate into neurons, glia, keratinocytes, smooth muscle cells, and melanocytes in vitro. Subsequently, we demonstrated that HAPstem cells could affect nerve and spinal cord regeneration in mouse models. We subsequently demonstrated that HAP stem cells differentiated into beating cardiac muscle cells. The differentiation potential to cardiac muscle is greatest in the upper part of the mouse whisker follicle. The beat rate of the cardiac muscle cells differentiated from HAP stem cells was stimulated by isoproterenol and inhibited by propanolol. The addition of activin A, bone morphogenetic protein 4, and basic fibroblast growth factor, along with isoproternal, induced the cardiac muscle cells to form tissue sheets of beating heart muscle cells. Under hypoxic conditions, HAP stem cells differentiated into troponin-positive cardiac-muscle cells at a higher rate that under normoxic conditions. Hypoxia did not influence the differentiation to other cell types. This method is appropriate for future use with human hair follicles to produce hHAP stem cells in sufficient quantities for future heart, nerve, and spinal cord regeneration in the clinic.

Genome-wide transcriptomics analysis identifies sox7 and sox18 as specifically regulated by gata4 in cardiomyogenesis

The transcription factors GATA4, GATA5 and GATA6 are important regulators of heart muscle differentiation (cardiomyogenesis), which function in a partially redundant manner. We identified genes specifically regulated by individual cardiogenic GATA factors in a genome-wide transcriptomics analysis. The genes regulated by gata4 are particularly interesting because GATA4 is able to induce differentiation of beating cardiomyocytes in Xenopus and in mammalian systems. Among the specifically gata4-regulated transcripts we identified two SoxF family members, sox7 and sox18. Experimental reinstatement of gata4 restores sox7 and sox18 expression, and loss of cardiomyocyte differentiation due to gata4 knockdown is partially restored by reinstating sox7 or sox18 expression, while (as previously reported) knockdown of sox7 or sox18 interferes with heart muscle formation. In order to test for conservation in mammalian cardiomyogenesis, we confirmed in mouse embryonic stem cells (ESCs) undergoing cardiomyogenesis that knockdown of Gata4 leads to reduced Sox7 (and Sox18) expression and that Gata4 is also uniquely capable of promptly inducing Sox7 expression. Taken together, we identify an important and conserved gene regulatory axis from gata4 to the SoxF paralogs sox7 and sox18 and further to heart muscle cell differentiation.

THIAMINE SUPPLEMENT THERAPY IMPROVES EJECTION FRACTION VALUE IN STAGE II HEART FAILURE PATIENTS

Thiamine, also called vitamin B1, is a water soluble vitamin that is involved in the formation of ATP in cells. The active metabolite of thiamine is a co-enzyme thiamine pyrophosphate (TPP) that plays an active role in carbohydrate metabolism and the formation of amino acid binding conjugates. Directly, thiamine may increase energy production in heart muscle cells through such mechanism, whereas in conditions of heart failure, a decrease in the contractility of heart muscle may be found. Therefore, thiamine supplementation is needed in stage II heart failure patients due to long-term use of furosemide that triggers the thiamine deficiency condition. Thiamine supplementation here is enabled to increase heart cells contractility which may ultimately increase the ejection fraction value of the heart muscle as a parameter of heart work efficiency measurement. The objective of this study was to evaluate the effect of thiamine administration as a therapeutic supplement in stage II of heart failure patients on the ejection fraction rate changes in pre and post thiamine supplement therapy for 28 days. The study was conducted using Cross Sectional Prospective Observational Analysis method between April and August 2016 in male patients with NYHA II heart failure who received furosemide therapy meeting the inclusion criteria at Heart Clinic Jemursari Islamic Hospital, Surabaya. Patients who fulfilled the inclusion and exclusion criteria in this study were 32 patients, 16 control patients and 16 treatment group patients between the ages of 35-75 years. During this study, after supplementation of thiamine 300 mg/day, 16 patients in the treatment group experienced an increase in ejection fraction rate (13.5%). The result of paired t test p=0.000 (p<α; α=0,05) showed significant difference between ejection fraction rate of pre and post thiamin supplementation. This study concluded that thiamine supplement therapy of 300 mg/day could increase the ejection fraction rate in patients of stage II heart failure.

Maduramicin induces apoptosis and necrosis, and blocks autophagic flux in myocardial H9c2 cells.

Maduramicin, a polyether ionophore antibiotic, is widely used as an anticoccidial agent in the poultry industry. It has been reported that maduramicin may cause heart and skeletal muscle cell damage, resulting in heart failure, skeletal muscle degeneration and even death in animals and humans, if improperly used. However, the molecular mechanism behind its capability to cause death of cardiac cells is not known. Here, we show that maduramicin induced apoptosis and necrosis in rat myocardial cells (H9c2). Maduramicin did not apparently upregulate the expression of pro-apoptotic proteins (e.g., BAD, BAK and BAX) or downregulate the expression of anti-apoptotic proteins (e.g. Bcl-2, Bcl-xL, Mcl-1 and survivin). Interestingly, maduramicin increased the expression of DR4 and TRAIL, activating caspases 8/3 and triggering cleavage of poly ADP ribose polymerase (PARP). In addition, maduramicin induced nuclear translocation of apoptosis inducing factor. Furthermore, maduramicin blocked autophagic flux, as evidenced by inducing accumulation of both LC3-II and p62/SQSTM1. Taken together, the above results suggest that maduramicin executes its toxicity in the myocardial cells at least by inducing caspase-dependent cell death through TRAIL/DR4-mediated extrinsic pathway and caspase-independent cell death by inducing apoptosis inducing factor nuclear translocation and blocking autophagic flux. Our findings provide a new insight into the molecular mechanism of maduramicin's toxicity in myocardial cells.

Adrenergic Stress Protection of Human iPS Cell-Derived Cardiomyocytes by Fast Kv7.1 Recycling.

The fight-or-flight response (FFR), a physiological acute stress reaction, involves positive chronotropic and inotropic effects on heart muscle cells mediated through β-adrenoceptor activation. Increased systolic calcium is required to enable stronger heart contractions whereas elevated potassium currents are to limit the duration of the action potentials and prevent arrhythmia. The latter effect is accomplished by an increased functional activity of the Kv7.1 channel encoded by KCNQ1. Current knowledge, however, does not sufficiently explain the full extent of rapid Kv7.1 activation and may hence be incomplete. Using inducible genetic KCNQ1 complementation in KCNQ1-deficient human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), we here reinvestigate the functional role of Kv7.1 in adapting human CMs to adrenergic stress. Under baseline conditions, Kv7.1 was barely detectable at the plasma membrane of hiPSC-CMs, yet it fully protected these from adrenergic stress-induced beat-to-beat variability of repolarization and torsade des pointes-like arrhythmia. Furthermore, isoprenaline treatment increased field potential durations specifically in KCNQ1-deficient CMs to cause these adverse macroscopic effects. Mechanistically, we find that the protective action by Kv7.1 resides in a rapid translocation of channel proteins from intracellular stores to the plasma membrane, induced by adrenergic signaling. Gene silencing experiments targeting RAB GTPases, mediators of intracellular vesicle trafficking, showed that fast Kv7.1 recycling under acute stress conditions is RAB4A-dependent.Our data reveal a key mechanism underlying the rapid adaptation of human cardiomyocytes to adrenergic stress. These findings moreover aid to the understanding of disease pathology in long QT syndrome and bear important implications for safety pharmacological screening.

P 138 Normal cognitive performances in patients with late-onset Pompe disease

Background and objective In addition to increased glycogen accumulations in heart and sckeletal muscle cells, liver cells and lymphocytes, autopsy findings indicate glycogen accumulations in the brain of patients with Pompe disease ( DiRocco et al., 2007 ). Children with classic infantile Pompe disease also present a delayed cerebral myelination ( Chien et al., 2006 ). The cognitive development ranged from normal to mild retarded ( Lai et al., 2016 , Spiridigliozzi et al., 2012 , Ebbink et al., 2012 ). Also in the adult form of Pompe disease there are significant deficits in the executive functions ( Borroni et al., 2013 ). The objective of this study was to examine cognitive functions in patients with late-onset Pompe disease using different neuropsychological test methods. Methods A total of 9 patients (4 females, 5 males) aged 26–81 (M = 53.78, SD = 14.89), with late-onset Pompe disease were tested neuropsychologically in different cognitive domains. This included the examination of the verbal (AVLTtotal), nonverbal (RCFTdelayed) and episodic memory (AVLTdelayed), the attention and concentration (TMT A/B, SDMT), the executive functions (TMT B, BADSkey search, S-Wordsword fluency) and the visuoconstructive abilities (RFCTcopy). Additionally, the severity of depressive symptoms was investigated (ADS-K). Results Patients had no significant deficits in the verbal, nonverbal or episodic memory. The attention and concentration capabilities, executive functions and visuoconstructive abilities were within mean normal range. Furthermore, no pathological values were found in the questionnaire used to examine clinically relevant depressive symptoms. Conclusion Cognitive deficits seem not to be associated symptoms in the adult form of Pompe disease. Thus, the described glycogen accumulations in the brain have no influence on the cognition.

Cells that fix the heart

Heart Regeneration The adult heart is thought to lack the capacity to self-repair. Any injury after, say, a heart attack causes scarring and may result in heart failure. In some animals, particularly when very young, heart muscle regeneration does occur. Even in adult mammals, new heart muscle cells (cardiomyocytes) can arise, but they are rare. Most maturing mammalian cardiomyocytes become binucleated and polyploid, and these seem to be incapable of regeneration. Patterson et al. found that a few “normal” mononucleated diploid cardiomyocytes (MNDCMs) occur in mice. Some individuals have more MNDCMs than others, and these individuals are better able to recover after heart injury. A gene called Tnni3k limits the number of MNDCMs, and it is this that appears to control the capacity for recovery after heart injury. Nat. Genet. 10.1038/ng.3929 (2017).