Intermittent hypoxia attenuates ischemia/reperfusion induced apoptosis in cardiac myocytes via regulating Bcl-2/Bax expression

Intermittent hypoxia has been shown to provide myocardial protection against ishemia/reperfusion-induced injury.Cardiac myocyte loss through apoptosis has been reported in ischemia/reperfusion injury. Our aim was to investigate whether intermittent hypoxia could attenuate ischemia/reperfusion-induced apoptosis in cardiac myocytes and its potential mechanisms. Adult male Sprague-Dawley rats were exposed to hypoxia simulated 5000 m in a hypobaric chamber for 6 h/day, lasting 42 days. Normoxia group rats were kept under normoxic conditions. Isolated perfused hearts from both groups were subjected to 30 min of global ischemia followed by 60 min reperfusion.Incidence of apoptosis in cardiac myocytes was determined by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and DNA agarose gel electrophoresis. Expressions of apoptosis related proteins,Bax and Bcl-2, in cytosolic and membrane fraction were detected by Western Blotting. After ischemia/reperfusion,enhanced recovery of cardiac function was observed in intermittent hypoxia hearts compared with normoxia group.Ischemia/reperfusion-induced apoptosis, as evidenced by TUNEL-positive nuclei and DNA fragmentation, was significantly reduced in intermittent hypoxia group compared with normoxia group. After ischemia/reperfusion,expression of Bax in both cytosolic and membrane fractions was decreased in intermittent hypoxia hearts compared with normoxia group. Although ischemia/reperfusion did not induce changes in the level of Bcl-2 expression in cytosolic fraction between intermittent hypoxia and normoxia groups, the expression of Bcl-2 in membrane fraction was upregulated in intermittent hypoxia group compared with normoxia group. These results indicated that the cardioprotection of intermittent hypoxia against ischemia/reperfusion injury appears to be in part due to reduce myocardial apoptosis. Intermittent hypoxia attenuated ischemia/reperfusion-induced apoptosis via increasing the ratio of Bcl-2/Bax, especially in membrane fraction.

Protective function of tocilizumab in human cardiac myocytes ischemia reperfusion injury

Objective:To investigate the protective function of tocilizumab in human cardiac myocytes ischemia-reperfusion injury.Methods:The human cardiac myocytes were treated by tocilizumab with different concentrations(1.0 mg/mL,3.0 mg/mL,5.0 mg/mL) for 24 h.then cells were cultured in ischemia environment for 24 h and reperfusion environment for 1 h.The MTT and flow cytometry were used to detect the proliferation and apoptosis of human cardiac myocytes,respectively.The mRNA and protein expressions of Bcl-2 and Bax were measured by qRT-PCR and western blot,respectively.Results:Compared to the negative group,pretreated by tocilizumab could significantly enhance the proliferation viability and suppress apoptosis of human cardiac myocytes after suffering ischemia reperfusion injury(P<0.05).The expression of Bcl-2 in tocilizumab treated group were higher than NC group(P<0.05).while the Bax expression were lower(P<0.05).Conclusions:Tocilizumab could significantly inhibit apoptosis and keep the proliferation viability of human cardiac myocytes after suffering ischemia reperfusion injury.Tocilizumab may obtain a widely application in the protection of ischemia reperfusion injury.

Antioxidant Effect of Human Selenium-containing Single-chain Fv in Rat Cardiac Myocytes

Reactive oxygen species（ROS） plays a key role in human heart diseases. Glutathione peroxidase（GPX） functions as an antioxidant as it catalyzes the reduction of hydroperoxide. In order to investigate the antioxidant effect of human selenium-containing single-chain Fv（Se-scFv-B3）, a new mimic of GPX, a model system of hydrogen peroxide（H202）-induced rat cardiac myocyte damage was established. The cardiac myocyte damage was characte- rized in terms of cell viability, lipid peroxidation, cell membrane integrity, and intracellular H202 level. The Se-scFv-B3 significantly reduced H2O2-induced cell damage as shown by the increase of cell viability, the decline of malondialdehyde（MDA） production, lactate dehydrogenase（LDH） release, and intracellular H2O2 level. So Se-scFv-B3 may have a great potential in the treatment of human heart diseases induced by ROS.

EFFECT OF PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR ACTIVATORS ON TUMOR NECROSIS FACTOR-αEXPRESSION IN NEONATAL RAT CARDIAC MYOCYTES

Objective To investigate the effect of peroxisome proliferator-activated receptor-α(PPARα) and PPARγactivators on tumor necrosis factor-α(TNFα) expression in neonatal rat cardiac myocytes. Methods Primary cultures of cardiac myocytes from 1- to 3-day-old Wistar rats were prepared, and myocytes were ex-posed to lipopolysaccharide (LPS) and varying concentrations of PPARαor PPARγactivator (fenofibrate or pioglitazone).RT-PCR and ELISA were used to measure TNFα, PPARα, and PPARγexpression in cultured cardiac myocytes. Transient tr-ansfection of TNFαpromoter with or without nuclear factor-kappaB (NF-κB) binding site to cardiac myocytes was performed. Results Pretreatment of cardiac myocytes with fenofibrate or pioglitazone inhibited LPS-induced TNFαmRNA and protein expression in a dose-dependent manner. However, no significant changes were observed on PPARαor PPARγmRNA expression when cardiac myocytes were pretreated with fenofibrate or pioglitazone. Proportional suppression of TNFαpromoter activity was observed when myocytes was transiently transfected with whole length of TNFαpromoter (-721/+17) after being stimulated with LPS and fenofibrate or pioglitazone, whereas no change of promoter activity was observed with transfection of TNFαreporter construct in deletion of NF-κB binding site (-182/+17). Conclusions PPARαand PPARγactivators may inhibit cardiac TNFαexpression but not accompanied by change of PPARαor PPARγmRNA expression. Therefore PPARαand PPARγactivators appear to play a role in anti-inflammation. The mechanism may partly be involved in suppression of the NF-κB pathway.

STUDY ON MECHANICAL INTERACTIONS BETWEEN SINGLE CARDIAC MYOCYTE AND ELASTIC SUBSTRATE

Quantitative investigation on mechanical characteristics of cardiac myocytes has important physiological significance. Based on elastic substrate technique, this paper develops a set of algorithms for high-efficiency cellular traction recovery. By applying a gradient-based digital image correlation method to track randomly distributed fluorescence microbeads on the deformed substrate induced by single cardiac myocyte, high-resolution substrate displacement field can readily be obtained. By using a numerical algorithm based on the integral Boussinesq solution, cell-substrate tractions are reconstructed in a stable and reliable manner. Finally, spatiotemporal dynamics of a single cardiac myocyte is investigated as it adheres to a polyacrylamide elastic substrate.

Effect of Cholic Acid on Fetal Cardiac Myocytes in Intrahepatic Choliestasis of Pregnancy

This study examined the effect of cholic acid （CA） on cultured cardiac myoeytes （CMs） from neonatal rats with an attempt to explore the possible mechanism of sudden fetal death in intra- hepatic cholestasis of pregnancy （ICP）. Inverted microscopy was performed to detect the impact of CA on the beating rates of rat CMs. MTT method was used to study the effect of CA on the viability of CMs. CMs cultured in vitro were incubated with 10 ~maol/L Ca2＋-sensitive fluorescence indicator fluo-3/AM. The fluorescence signals of free calcium induced by CA were measured under a laser scanning confocal microscope. The results showed that CA decreased the beating rates of the CMs in a dose-dependent manner. CA could suppress the activities of CMs in a time- and dose-dependent manner. CA increased the concentration of intracellular free calcium in a dose-dependent manner. Our study suggested that CA could inhibit the activity of CMs by causing calcium overload, thereby leading to the sudden fetal death in ICP.

Role of NF-κB in protection of EPO pretreatment on neonatal rat cardiac myocytes with hypoxia/reoxygenation injury

Objective：To observe the protective effects of erythropoietin （EPO） pretreatment on cardiac myocyte with hypoxia/reoxygenation （H/R） injury and the role of NF-κBin this effects. Methods：After the H/R model of cardiac myocytes of neonatal rats was established, the cultured cardiac myocytes were divided into 4 groups, including EPO pretreatment group （ EPO 10 U/ml 24 h before H/R）, EPO pretreatment ＋ PDTC group（EPO 10 U/ml and PDTC 5 μg/ml 24 h before H/R）, PDTC group （PDTC 5 μg /ml 24 h before H/R） and eomrolgroup. Before and after the H/R, assay of LDH concentration in the culture medium, the survival rate of the myocytes tested by MTT chromatometry and the apoptosis by flow cytometry were undertaken. Activation of NF-κB was determined by EMSA before and after H/R. Results：EPO pretreatment markedly reduced the LDH concentration in the medium, elevated the survival rate of myocytes and inhibited the apoptosis after H/R. Addition of PDTC during the pretreatment abol- ished the protective effects of EPO pretreatment. NF-κB was markedly activated during EPO pretreatment and PDTCinhibited the activation. However, after H/R, the activity of NF-κB in myocytes with EPO pretreatment was significantly inhibited compared to the other myocytes. Conclusion：NF-κB is significantly activated during EPO pretreatment, but is inhibited after H/R, which is correlated with the protective effects of EPO pretreatment on cardiac myocytes with H/R. This phenomenon can be explained as the negative feedback mechanism of the activation of NF-κB.

Gene Product Expression of Cyclin D_2 and p16 During the Transition from Cardiac Myocyte Hyperplasia to Hypertrophy

The current study was to investigate mRNA expression of cyclin D 2 and p16 during the transition from cardiac myocyte hyperplasia to hypertrophy. Cultured cardiac myocytes (CM) and fibroblasts (FC) obtained from 1 day old Sparague Dawley rats were used in this study. We have determined (1) hyperplasia by cell growth curve and fluorescence activated cell sorting (FACS); and (2) ultrastructure by electron microscope observation; and (3) expressions of cyclin D 2 mRNA and p16 mRNA by using in situ hybridization and image analysis. The results were shown (1) Results of cell growth curve and FACS analysis showed CM could proliferate in the first 3 cultured days (4 days in postnatal development). But the ability decreased quickly, concomitant with the differentiation. (2) The ultrastructure of CM showed the large amount of myofilaments and mitochondrion and FC showed moderate amount of rough endoplasmic reticulum. (3) The expression of cyclin D 2 mRNA in 3 , 4 , 5 day CM group was 0.89 times(p<0.05), 0.80 times (p<0.05)and 0.56 times (p<0.01)of that in 1 day group respectively. P16 mRNA in 2 , 3 , 4 , 5 day CM group were 1.63 times(p<0.01),1.72 times(p<0.01),1.99 times (p<0.01)and 2.84 times (p<0.01) of that in 1 day group respectively. It can be concluded that cultured neonatal rat cardiac myocytes could proliferate during the first 3 cultured days, but the ability of proliferation decreased, from the fourth day, concomitant with differentiation. Cyclin D 2 and p16 have the key roles during the transition from myocyte hyperplasia to hypertrophy.

Effects of simvastatin on hypertrophy and PTEN expression of rat cardiac myocytes

Objective To study the effects of simvastatin on the hypertrophy of cultured rat cardiac myocytes induced by serum and the role ofphosphatase and tensin homolog deleted on chromosome ten （PTEN） in the signal pathway. Methods Cultured neonatal Sprague- Dawley （SD） rat cardiac myocytes were treated with 15% fetal bovine serum, or without serum, or different consentrations of simvastatin. Image analysis system was used to measure the cardiac myocytes surface area. Protein synthesis of myocytes was measured via [3H]-leucine incorporation method. The expression level of atrial natriuretic peptide （ANP） mRNA in myocytes was determined with reverse transcription polymerase chain reaction （RT-PCR）. The mRNA and protein expression levels of PTEN in cardiac myocytes were investigated with RT-PCR and Western blot respectively. Results At 24 hours, cardiac myocytes surface area was significantly higher in 15% serum group （1611.16± 160.75 lam2） than in serum-free group （538.04±118.60 ±tm2, P〈0.01）. Simvastatin decreased the cell surface area in a concentration dependent manner. The cell surface area in 10-5 and 10-6 mol/L simvastatin groups were 799.84＋ 167.70 ±tm2 and 1076.88± 199.28 um2 respectively, which were both significantly lower than that in 15% fetal bovine serum group （P〈0.01）. Incorporation rate of [3H]-leucine was significantly higher in 15% fetal bovine serum group （2360± 106cpm/well） than that in serum-free group （1305±92 cpm/well, P〈0.01）. Incorporation rate of [3H]-leucine in 10.5 and 10.6 mol/L simvastatin groups were 1707±101 clam/well and 1962±125 cpm/well respectively, which were both lower than that in serum group （P〈0.01）. With the increase of simvastatin concentration, the expression level ofANP mRNA in cardiac myocytes was decreased gradually, which were 0.29±0.03 and 0.40-±0.03 respectively in 10.5 and 10-6 mol/L simvastatin groups, and significantly lower than that in serum group（0.60-±.03, P〈0.01）. Simvastatin increased the expressions of PTEN mRNA and protein in cardiac myocytes in a concentration dependent manner. PTEN mRNA expression level in 10-7, 10-6and 105mol/L simvastatin groups were 0.38±0.03, 0.83±0.04 and 0.85±0.05, respectively, which were all higher than that in 15% fetal bovine serum group （0.29±0.04, P〈0.05）. Similarly, PTEN protein level in 10-7, 10-6 and 10.5 mol/L simvastatin groups （39.25±3.41, 46.35±1.78 and 47.22±2.39 respectively） were also significantly higher than that in 15% fetal bovine serum group （32.21±4.06, P〈0.05）. Conclusion Simvastatin can inhibit the hypertrophy of cultured rat cardiac myoeytes induced by serum, and the increase of expression level of PTEN might be involved in the mechanism （J Geriatr Cardio12010; 7：47-51）.

FINITE ELEMENT ANALYSIS OF CARDIAC MYOCYTE DEBONDING AND REORIENTATION DURING CYCLIC SUBSTRATE STRETCH EXPERIMENTS

The substrate stretch experiment, which is carried out on several kinds of adherent cells, is usually used to catch the physiological variation and morphological response to cyclic substrate deformation. In this paper, stretch loading was exerted on cardiac myocytes cultured on silica substrates using a custom-made substrate stretch device. The effect of stretch on the alignment orientation of cardiac myocytes was studied through morphocytological statistics. Under cyclic stretch stimulus, the long axes of cardiac myocytes oriented perpendicularly to the stretch direction for continuous stretch acting. However, the mechanism underlying these behaviors is not well understood from such in vitro tests. Finite element （FE） model was developed in the analysis to investigate these behaviors. Xu-Needleman formulation was used to define the interaction behavior for contact surfaces between cell and substrate. The role of cell viscoelasticity nature is studied in adherent cell debonding with the substrate and aligning perpendicular to the stretch direction during long time cyclic stretch stimulation. There were four different strain magnitudes considered in the simulation to find out the cell debonding affected by the cyclic strains. The potential role of cyclic strain frequency in regulating cell debonding and alignment was also studied using FE analysis.

In Vitro Study on Mesenchymal Stem Cells:Anti-apoptotic Effects on Cardiac Myocytes

Objectives To investigate the anti-apoptotic effects of mesenchymal stem cells （MSCs） on hypoxic injured cardiac myocytes in vitro. Methods MSCs were isolated from bone marrow of Sprague-Dawley （SD） rats, and cardiac myocytes from neonatal rats. The rat cardiac myocytes were co-cultured with MSCs or MSC-conditioned media in anoxia （95% N2 ±5% CO2） for 72 hours. Cell apoptosis was measured by Hoechst 33258 staining. The expression of Bcl-2 and Bax in cardiac myocytes was tested by Western Blot. Results The apoptotic rate was 51.6% ± 2.4% when cardiac myocytes were cultured in continuous hypoxia and was significantly decreased when cardiac myocytes were cocultured with MSCs or MSC-conditioned media （ 15.1% ± 5.4% and 24. 0% ± 4.2% respectively, P 〈 0. 001 ）. The decreased expression of Bax in the cardiac myocytes was greatly related to the decreasing of apoptosis, but there was no difference in Bcl-2 expression among these groups. Conclusions Co-cultured MSCs showed significant anti-apoptotic effects on cardiac myocytes in continuous hypoxia. The mechanism may be the interact of cell to cell and paracrine of cytokines which effected the expression of Bax in the cardiac myocytes.

Effect of post-burn serum on free cytosolic calcium in isolated cardiac myocytes of adult rats

The ohjective of this study was to determine whether the free intracellular calcium concentration ([Ca2+] ) of isolatedcardiac myocytes increased with the stimulation of post-burn serum(PBS) in adult rats. Cardiac myocytes were isolated by collage-nase using Langendorff’s perfusion apparatus, and [Ca2+], was measured using the fluorescent indicator Fain-2. The normal[Ca2+], was 101. 3 ± 21. 3 nmol/L in cardic myocytes. PBS at various postburn home could very significantly increase the[Ca2+]i (P< 0. 01 ) and, 6 h PBS had the strongest effect. However, no significant difference was found between the effects of2 h PBS and 4 h PBS (P >0. 05 ). Both calcium channel antagonist verapamil(30 umol/L) and the inhibitor of ryanodine receptoron sarcoplasmic reticulum procaine (2 mmol/L), very significantly inhibited the action of 6 h PBS, with the inhibition rate of47. 7% and 67. 6% respectively. The inhibiting rate of procaine was significantly greater than that of verapamil (P < 0. 01 ). Theresults suggested that PBS could stimulate the increase of [Ca2+], in isolated cardiac myocytes of adult rats, in which calcium release from intracellular stores might play greater roles. Agents modulating the calcium release from intracellular stores are expectedto have great significance in preventing the organic injuries due to the increases of [ Ca2+]i.

Overexpression of GATA binding protein 4 and myocyte enhancer factor 2C induces differentiation of mesenchymal stem cells into cardiac-like cells

BACKGROUND Heart diseases are the primary cause of death all over the world.Following myocardial infarction,billions of cells die,resulting in a huge loss of cardiac function.Stem cell-based therapies have appeared as a new area to support heart regeneration.The transcription factors GATA binding protein 4(GATA-4)and myocyte enhancer factor 2C(MEF2C)are considered prominent factors in the development of the cardiovascular system.AIM To explore the potential of GATA-4 and MEF2C for the cardiac differentiation of human umbilical cord mesenchymal stem cells(hUC-MSCs).METHODS hUC-MSCs were characterized morphologically and immunologically by the presence of specific markers of MSCs via immunocytochemistry and flow cytometry,and by their potential to differentiate into osteocytes and adipocytes.hUC-MSCs were transfected with GATA-4,MEF2C,and their combination to direct the differentiation.Cardiac differentiation was confirmed by semiquant itative real-time polymerase chain reaction and immunocytochemistry.RESULTS hUC-MSCs expressed specific cell surface markers CD105,CD90,CD44,and vimentin but lack the expression of CD45.The transcription factors GATA-4 and MEF2C,and their combination induced differentiation in hUC-MSCs with significant expression of cardiac genes i.e.,GATA-4,MEF2C,NK2 homeobox 5(NKX2.5),MHC,and connexin-43,and cardiac proteins GATA-4,NKX2.5,cardiac troponin T,and connexin-43.CONCLUSION Transfection with GATA-4,MEF2C,and their combination effectively induces cardiac differentiation in hUC-MSCs.These genetically modified MSCs could be a promising treatment option for heart diseases in the future.

HGF percutaneous endocardial injection induces cardiomyocyte proliferation and rescues cardiac function in pigs

Objective：To investigate the effect of cardiomyocyte proliferation induced by human hepatocyte growth factor（HGF）in pigs with chronic myocardial infarction（CMI）.Methods：A steerable,deflectable 7F catheter incorporating a 27-guage needle was advanced percutaneously to the left ventricular myocardium of 18 pigs with CMI.Pigs were randomized（1：1：1）to receive adenoviral vector HGF（total dose,1×10^10 genome copies）,which was administered as five injections into the infarcted myocardium（total,1.0 mL）,or saline,or Ad-null（control groups）.Injections were guided by Ensite NavX left ventricular electroanatomical mapping.HGF and cyclin proteins were detected by western blot and immunoprecipitation analysis.Histological and immunohistochemical analysis determined proliferating cardiomyocytes.Myocardial perfusion and cardiac function were estimated by Gated-Single Photon Emission Computed Tomography（G-SPECT）.Results：Western blot analyses showed that HGF were predominantly expressed in the infarct core and border in the myocardium of the infarcted heart.G-SPECT analysis indicated that the HGF group had better cardiac function and myocardial perfusion four weeks after the injection of Ad-HGF than before the injection of Ad-HGF.After treatment there were more proliferating cardiomyocytes in the HGF group compared to either of the control groups.Furthermore,the HGF group myocardial samples expressed higher levels of p-Akt,cyclin A,cyclin E,cyclin D1,cdk2,cdk4 than those in the control groups.Conclusion：The over-expression of HGF activates pro-survival pathways,induces cardiomyocyte proliferation,and improves the perfusion and function of the porcine CMI heart.

Effect of L-carnitine on Cardiomyocyte Apoptosis and Cardiac Function in Patients Undergoing Heart Valve Replacement Operation

Summary： The effects of L-carnitine, as an ingredient of cardioplegia solution, on cardiac function and cardiomyocyte apoptosis in patients undergoing heart valve replacement operation were investigated. Twenty-three cases undergoing heart valve replacement with cardiopulmonary bypass （CPB） were randomly allocated into two groups： L-carnitine group （n=12, 12 g/L L-carnitine was put in the ST. Thomas cardioplegia） and control group （n=11, identical to the L-carnitine group except that normal saline was administered instead of L-carnitine）. Serum cardial troponin I （cTnI） levels, the left ventricular ejection fraction （LVEF）, and cardiac index （CI） were measured perioperatively. A bit of myocardial tissue obtained from right atria was taken before CPB and by the end of intracardiac procedure to undergo electron microscopy examination and estimate apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling （TUNEL）. From the end of CPB to 3 days after operation, the serum levels of cTnI in the L-carnitine group was significantly lower than that in the control group （P〈0.05）. Heart color ultrasonogram showed that the CI index and LVEF at 7th day postoperatively in the L-carnitine group were significantly higher than in the control group （P〈0.05）. Compared to the control group, L-carnitine significantly alleviated the morphologic changes of cardiac muscle cells （electron microscopy examination） and decreased the amounts of apoptotic cardiac muscle cells （TUNEL）. Furthermore, the dosage of vasoactive drugs used after operation was significantly less in the L-carnitine group （P〈0.01）. It was concluded that L-carnitine cardioplegia solution could improve cardiac function in patients undergoing heart valve replacement operation and alleviate CPB-mediated apoptosis of cardiac muscle cells.

Detection of cardiac myosin binding protein-C (cMyBP-C) by a phospho-specific PKD antibody in contracting rat cardiomyocytes

Protein phosphorylation plays an important role in physiological processes, such as muscle contraction. Phospho-specific antibodies have become powerful tools to study these processes. Cardiac myosin binding protein-C (cMyBP-C) is one of the proteins that make up the contractile apparatus of cardiomyocytes. Phosphorylation of cMyBP-C is essential for normal cardiac function, since dephosphorylation of this protein leads to its degradation and has been associated with cardiomyopathy. One of the upstream kinases, which phosphorylate cMyBP-C, is protein kinase D (PKD). While studying the role of PKD in cMyBP-C phosphorylation, we tried to analyze phosphorylation of PKD with a phospho-specific PKD-Ser744/748 antibody. Contrary to the expected 115 kDa, a signal was found for a 150-kDa protein. By MALDI-TOF mass spectrometry, we identified this protein to be cMyBP-C. These data were confirmed by immunostaining using the p-PKD-Ser744/748 antibody, which displayed a striated pattern similar to the one observed for a regular cMyBP-C antibody. To our knowledge there are no antibodies commercially available for phosphorylated cMyBP-C. Thus, the p-PKD-Ser744/748 antibody can accelerate research into the role of cMyBP-C phosphorylation in cardiomyocytes.

ROLE OF CALCINEURIN IN ANGIOTENSIN II- INDUCED CARDIAC MYOCYTE HYPERTROPHY OF RATS

The present study investigated the role of calcineurin in angiotensin II(AngII)- induced cardiac myocyte hypertrophy of rats. Method. The primary cardiac myocytes were cultured under the standard conditions. The calcineurin activity in AngII- treated cardiomyocytes was tested by using PNPP;protein synethsis rate was assessed by 3H- leucine incorporation; atrial natriuretic factor(ANF) mRNA level was determined by Northern blot analysis. Cell viability was estimated by lactate dehydrogenase(LDH) levels in cultured medium and by dyed cell numbers. Result. After stimulation of 10,100 and 1 000nmol/L of AngII, calcineurin activities in the cardiomyocytes were increased by 13％ ,57％ (P Conclusion. During AngII- induced cardiac myocyte hypertrophy, calcineurin signal pathway is activated, and inhibition of the pathway can attenuate AngII- induced cardiac myocyte hypertrophy, which suggests that the calcineurin signal pathway may play an important role in AngII- induced myocardial hypertrophy of rats.

Approach to cardiac masses: Thinking inside and outside the box

In this editorial we comment on the article by Huffaker et al,published in the current issue of the World Journal of Clinical Cases.Cardiac masses encompass a broad range of lesions,potentially involving any cardiac structure,and they can be either neoplastic or non-neoplastic.Primitive cardiac tumors are rare,while metastases and pseudotumors are relatively common.Cardiac masses frequently pose significant diagnostic and therapeutic challenges.Multimodality imaging is fundamental for differential diagnosis,treatment,and surgical planning.In particular cardiac magnetic resonance(CMR)is currently the gold standard for noninvasive tissue characterization.CMR allows evaluation of the relationship between the tumor and adjacent structures,detection of the degree of infiltration or expansion of the mass,and prediction of the possible malignancy of a mass with a high accuracy.Different flow charts of diagnostic work-up have been proposed,based on clinical,laboratory and imaging findings,with the aim of helping physicians approach the problem in a pragmatic way(“thinking inside the box”).However,the clinical complexity of cancer patients,in particular those with rare syndromes,requires a multidisciplinary approach and an open mind to go beyond flow charts and diagnostic algorithms,in other words the ability to“think outside the box”.

Recent advances in the diagnostic methods and therapeutic strategies of transthyretin cardiac amyloidosis

Cardiac amyloidosis is a progressive disease characterized by the buildup of amyloid fibrils in the extracellular space of the heart.It is divided in 2 main types,immunoglobulin light chain amyloidosis and transthyretin amyloidosis(ATTR),and ATTR amyloidosis is further divided in 2 subtypes,non-hereditary wild type ATTR and hereditary mutant variant amyloidosis.Incidence and prevalence of ATTR cardiac amyloidosis is increasing over the last years due to the improvements in diagnostic methods.Survival rates are improving due to the development of novel therapeutic strategies.Tafamidis is the only disease-modifying approved therapy in ATTR amyloidosis so far.However,the most recent advances in medical therapies have added more options with the potential to become part of the therapeutic armamentarium of the disease.Agents including acoramidis,eplontersen,vutrisiran,patisiran and anti-monoclonal antibody NI006 are being investigated on cardiac function in large,multicenter controlled trials which are expected to be completed within the next 2-3 years,providing promising results in patients with ATTR cardiac amyloidosis.However,further and ongoing research is required in order to improve diagnostic methods that could provide an early diagnosis,as well as survival and quality of life of these patients.