Loss Of Myofibrils Research Articles

Mechanisms of vibration-induced structural myocardial remodeling

The review analyzes literature data on structural changes in the heart of patients with vibration disease, as detected by echocardiographic methods. Particularly, it highlights concentric remodeling of the left ventricle chambers and disturbances in diastolic function. The review also discusses a 1.2-fold decrease in heart structure intensity compared to healthy individuals (p 0.05). Furthermore, it examines changes in morphometric and bioenergetic parameters of cardiomyocytes under different experimental vibration modes (7 and 56 sessions at a frequency of 8 Hz), confirming the disruptions in the relationship between the spatial configuration of the heart cavities, contractile ability, and energy supply potential. Loss of cardiac myofibrils represents the transition from myocardial hypertrophy to decompensation, accompanied by an increase in degenerative (dystrophic) signs such as the loss of sarcomeres in cardiomyocytes. Understanding these pathological (morphological) processes requires consideration of various mediators that regulate cell metabolism, proliferation, growth, and survival, including stromal interaction molecule, calcium ATPase of the endo(sarco)plasmic reticulum, inositol-1,4,5-triphosphate receptor, protein that forms CRAC channels, and transient receptor potential canonical. The degradation system of the extracellular matrix, including matrix metalloproteinases and tissue inhibitors, plays a crucial role in structural cardiac remodeling. This system regulates the rate of mRNA synthesis on the DNA matrix by binding to specific DNA regions that control cardiac nutrition and plasticity. The review suggests that these findings can help explain some patterns of cardiac remodeling development in patients with vibration disease and determine the direction of pathogenetically based therapy. This therapy should consider not only the vibration-protective effect of drugs but also their ability to inhibit and regress myocardial remodeling.

Protective Effects of Hesperetin on Cardiomyocyte Integrity and Cytoskeletal Stability in a Murine Model of Epirubicin-Induced Cardiotoxicity: A Histopathological Study

Anthracyclines, including epirubicin (Epi), are effective chemotherapeutics but are known for their cardiotoxic side effects, primarily inducing cardiomyocyte apoptosis. This study investigates the protective role of hesperetin (HSP) against cardiomyopathy triggered by Epi in a murine model. Male CD1 mice were divided into four groups, with the Epi group receiving a cumulative dose of 12 mg/kg intraperitoneally, reflecting a clinically relevant dosage. The co-treatment group received 100 mg/kg of HSP daily for 13 days. After the treatment period, mice were euthanized, and heart tissues were collected for histopathological, immunofluorescence/immunohistochemistry, and transmission electron microscopy (TEM) analyses. Histologically, Epi treatment led to cytoplasmic vacuolization, myofibril loss, and fiber disarray, while co-treatment with HSP preserved cardiac structure. Immunofluorescent analysis of Bcl-2 family proteins revealed Epi-induced upregulation of the pro-apoptotic protein Bax and a decrease in anti-apoptotic Bcl-2, which HSP treatment reversed. TEM observations confirmed the preservation of mitochondrial ultrastructure with HSP treatment. Moreover, in situ detection of DNA fragmentation highlighted a decrease in apoptotic nuclei with HSP treatment. In conclusion, HSP demonstrates a protective effect against Epi-induced cardiac injury and apoptosis, suggesting its potential as an adjunctive therapy in anthracycline-induced cardiomyopathy. Further studies, including chronic cardiotoxicity models and clinical trials, are warranted to optimize its therapeutic application in Epi-related cardiac dysfunction.

Cardioprotective role of a magnolol and honokiol complex in the prevention of doxorubicin-mediated cardiotoxicity in adult rats.

Doxorubicin (DOXO) induces marked cardiotoxicity, though increased oxidative stress while there are some documents related with cardioprotective effects of some antioxidants against organ-toxicity during cancer treatment. Although magnolia bark has some antioxidant-like effects, its action in DOXO-induced heart dysfunction has not be shown clearly. Therefore, here, we aimed to investigate the cardioprotective action of a magnolia bark extract with active component magnolol and honokiolcomplex (MAHOC; 100mg/kg) in DOXO-treated rat hearts. One group of adult male Wistar rats was injected with DOXO (DOXO-group; a cumulative dose of 15mg/kg in 2-week) or saline (CON-group). One group of DOXO-treated rats was administered with MAHOC before DOXO (Pre-MAHOC group; 2-week) while another group was administered with MAHOC following the 2-week DOXO (Post-MAHOC group). MAHOC administration, before or after DOXO, provided full survival of animals during 12-14weeks, and significant recoveries in the systemic parameters of animals such as plasma levels of manganese and zinc, total oxidant and antioxidant statuses, and also systolic and diastolic blood pressures. This treatment also significantly improved heart function including recoveries in end-diastolic volume, left ventricular end-systolic volume, heart rate, cardiac output, and prolonged P-wave duration. Furthermore, the MAHOC administrations improved the structure of left ventricles such as recoveries in loss of myofibrils, degenerative nuclear changes, fragmentation of cardiomyocytes, and interstitial edema. Biochemical analysis in the heart tissues provided the important cardioprotective effect of MAHOC on the redox regulation of the heart, such as improvements in activities of glutathione peroxidase and glutathione reductase, and oxygen radical-absorbing capacity of the heart together with recoveries in other systemic parameters of animals, while all of these benefits were observed in the Pre-MAHOC treatment group, more prominently. Overall, one can point out the beneficial antioxidant effects of MAHOC in chronic heart diseases as a supporting and complementing agent to the conventional therapies.

Cardioprotective potential of mitochondria-targeted antioxidant, mito-TEMPO, in 5-fluorouracil-induced cardiotoxicity

PurposeThe mitochondria-targeted antioxidants (MTAs) are known to offer protection against mitochondrial oxidative stress. The recent evidences support their role in mitigating oxidative stress-induced diseases, including cancer. Therefore, this study investigated cardioprotective potential of mito-TEMPO against 5-FU-induced cardiotoxicity.MethodsMito-TEMPO was administered to male BALB/C mice (intraperitoneally, 0.1 mg/kg b.w. for 7 days) followed by intraperitoneal administration of 5- FU (12 mg/kg b.w. for 4 days). During this period, mito-TEMPO treatment was also continued. The cardioprotective potential of mito-TEMPO was assessed by evaluating cardiac injury markers, extent of non-viable myocardium and histopathological alterations. Mitochondrial functional status and mitochondrial oxidative stress were assessed in cardiac tissue. 8-OHdG expression and apoptotic cell death were assessed using immunohistochemical techniques.ResultsThe level of cardiac injury markers CK-MB and AST were significantly (P ≤ 0.05) decreased in mito-TEMPO pre-protected group which was further reflected in histopathology as decrease in the percentage of non-viable myocardial tissue, disorganization, and loss of myofibrils. Mito-TEMPO ameliorated mtROS, mtLPO and conserved mitochondrial membrane potential. Further, it had significantly (P ≤ 0.05) improved the activity of mitochondrial complexes and mitochondrial enzymes. A significant (P ≤ 0.05) increase in the level of mtGSH, activity of mitochondrial glutathione reductase, glutathione peroxidase, and mitochondrial superoxide dismutase was observed. A decreased expression of 8-OHdG and reduced apoptotic cell death were observed in mito-TEMPO pre-protected group.ConclusionMito-TEMPO effectively mitigated 5-FU-induced cardiotoxicity by modulating mitochondrial oxidative stress, hence may serve as a protective agent/adjuvant in 5-FU-based combinatorial chemotherapy.

THE PROTECTIVE EFFECTS OF GLYCYRRHIZIN ON DOXORUBICIN-INDUCED CARDIOTOXICITY IN RATS

ABSTRACT Objective: Doxorubicin (DOX) is a type of chemotherapy drug frequently used to treat different malignancies. However, one of the most serious adverse effects of DOX usage is the potential of cardiotoxicity. Cardioprotective medications may be used to reduce cardiac damage because of DOX therapy. Glycyrrhizin (GL) is found in high amounts in the roots of the ‘Licorice’ plant from the Glycyrrhiza species. Due to its possible effects on blood pressure (BP) and cardiovascular health, GL has attracted attention concerning the heart. Oxidative stress and inflammatory process have been shown to be responsible for DOX-induced cardiotoxicity (DIC). For this reason, in consequence of its possible pharmacological benefits, such as antiinflammatory and antioxidant GL has been researched in this study. Here in, we aimed to investigate the protective effects of GL on DIC. Material and Methods: In this study, thirty-two male Wistar albino adult male rats were used. Four groups of rats were assigned at randomly: Control, DOX, GL+DOX, and GL groups. DOX was given 20 mg/kg intraperitoneally (i.p.) and 100 mg/kg GL was administered orally (p.o.) once a day for 14 days. Electrocardiography (ECG) and BP records of the rats were obtained. In addition, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels in the tissue were measured. Histopathological analyses were performed on the myocardium and descending aorta. Results: In the DOX group, mean and diastolic BP were higher than in the control group (p<0.05). In the GL+DOX group, diastolic BP was lower than in the DOX group (p<0.05). Pathological ECG changes such as ST segment changes and T negativity were observed in DOX-treated groups. MDA, SOD, CAT, and GSH levels studied in heart tissue were similar in all groups (p>0.05). GSH level in descending aorta was significantly lower in the GL+DOX group compared to the other groups (p<0.05). In the DOX group, degenerated cardiomyocyte density, interstitial edema, and severity of congestion-hemorrhage were statistically significantly increased compared to the control group (p<0.05). On the other hand, degenerated cardiomyocyte density was found to be significantly decreased in the GL+DOX group compared to the DOX group (p<0.05). In the DOX group, thinning of elastic lamellae and loss of myofibrils in muscle cells were observed in the descending aorta. Therefore, the histopathological alterations identified in the DOX group exhibited a significant statistical improvement in the GL+DOX group (p<0.05). Conclusion: Based on the study's findings, GL can regulate high blood pressure caused by DOX and also alleviate the toxic effects of DOX on both the myocardium and descending aorta.

Fucoxanthin alleviated myocardial ischemia and reperfusion injury through inhibition of ferroptosis via the NRF2 signaling pathway.

Background: Myocardial ischemia and reperfusion injury (MIRI) is a severe complication of revascularization therapy in patients with myocardial infarction. Therefore, there is an urgent requirement to find more therapeutic solutions for MIRI. Recently, ferroptosis, which is characterized by lipid peroxidation, was considered a critical contributor to MIRI. Fucoxanthin (FX), a natural antioxidant carotenoid, which is abundant in brown seaweed, exerts protective effects under various pathological conditions. However, whether FX alleviates MIRI is unclear. This study aims to clarify the effects of FX on MIRI. Methods: Mice with left anterior descending artery ligation and reperfusion were used as in vivo models. Neonatal rat cardiomyocytes (NRCs) induced with hypoxia and reperfusion were used as in vitro models. TTC-Evans blue staining was performed to validate the infarction size. Transmission electron microscopy was employed to detect mitochondrial injury in cardiomyocytes. In addition, 4 weeks after MIRI, echocardiography was performed to measure cardiac function; fluorescent probes and western blots were used to detect ferroptosis. Results: TTC-Evans blue staining showed that FX reduced the infarction size induced by MIRI. Transmission electron microscopy showed that FX ameliorated the MIRI-induced myofibril loss and mitochondrion shrinkage. Furthermore, FX improved LVEF and LVFS and inhibited myocardial hypertrophy and fibrosis after 4 weeks in mice with MIRI. In the in vitro study, calcein AM/PI staining and TUNEL staining showed that FX reduced cell death caused by hypoxia and reperfusion treatment. DCFH-DA and MitoSOX probes indicated that FX inhibited cellular and mitochondrial reactive oxygen species (ROS). Moreover, C11-BODIPY 581/591 staining, ferro-orange staining, MDA assay, Fe2+ assay, 4-hydroxynonenal enzyme-linked immunosorbent assay, and western blot were performed and the results revealed that FX ameliorated ferroptosis in vitro and in vivo, as indicated by inhibiting lipid ROS and Fe2+ release, as well as by modulating ferroptosis hallmark FTH, TFRC, and GPX4 expression. Additionally, the protective effects of FX were eliminated by the NRF2 inhibitor brusatol, as observed from western blotting, C11-BODIPY 581/591 staining, and calcein AM/PI staining, indicating that FX exerted cardio-protective effects on MIRI through the NRF2 pathway. Conclusion: Our study showed that FX alleviated MIRI through the inhibition of ferroptosis via the NRF2 signaling pathway.

The Reaction of Myocardial Capillaries to Crystalloid Cardioplegia of Different Durations in Patients with Valvular Pathology and Coronary Heart Disease

The aim. To study the morphological manifestations of the response of the myocardial capillaries to cardioplegia in patients with valvular defects and coronary heart disease.
 Materials and methods. Morphological research of operative and sectional material was carried out. Myocardium fragments for microscopical study were obtained from patients at different stages of an open-heart surgery and patients who died at the stage of conservative treatment without surgical intervention. Similar samples of the myocardium of a healthy young man who died from injuries incompatible with life were studied as a control. For electron microscopy study, samples of myocardium were taken from patients at the 185th minute of perfusion.
 Results. Histological preparations of the myocardium showed pronounced diffuse hypertrophy of cardiomyocytes (CMCs), sometimes at the stage of decompensation (perinuclear edema, loss of myofibrils, apoptosis). This transformation of CMCs was obviously related to their functional overload caused by combined defects of the mitral and aortic valves. Changes in muscle fibers were accompanied by interstitial and perinuclear fibrosis. In the pool of coronary arteries affected by atherosclerosis, signs of small focal coronary fibrosis were visible, as well as rough post-infarction scars in 3 patients. All the patients had signs of acute hypoxic damage to the myocardium in the form of CMCs shortening and interstitial edema.
 Conclusions. In patients with combined defects of the aortic and mitral valves of the heart with coronary artery disease, the phenomena of myocardial fibrosis prevail. Heart valve disease combined with coronary heart disease lead to the development of both alterative and compensatory-adaptiveprocesses in the vessels of the microcirculatory bed. The greatest loss of vital organelles in small vessels is observed at 185 min after administration of cardioplegic solution, irreversible changes develop 3 h after perfusion.

Prophylactic Evidence of MSCs-Derived Exosomes in Doxorubicin/Trastuzumab-Induced Cardiotoxicity: Beyond Mechanistic Target of NRG-1/Erb Signaling Pathway

Trastuzumab (Trz) is a humanized monoclonal antibody targeting epidermal growth factor receptor 2 (HER2; ErbB2). The combined administration of Trz and doxorubicin (DOX) has shown potent anti-cancer efficacy; however, this regimen may be accompanied by severe cardiac toxicity. Mesenchymal stem cells (MSCs)-derived exosomes are nanosized vesicles that play a crucial role in cell–cell communication and have shown efficacy in the treatment of various diseases. In this study, we aim to investigate the cardioprotective effects of MSCs-derived exosomes in a DOX/Trz- mediated cardiotoxicity model, and the possible mechanisms underlying these effects are elucidated. Forty-nine male rats were randomly assigned into four groups: Group I (control); Group II (Dox/Trz); Group III (protective group); and Group IV (curative group). Cardiac hemodynamic parameters, serum markers of cardiac injury, oxidative stress indices, and cardiac histopathology were investigated. Further, transcript profile of specific cardiac tissue injury markers, apoptotic markers, and fibrotic markers were analyzed using qRT-PCR, while the protein expressions of pAkt/Akt, pERK/ERK, pJNK/JNK, pJNK/JNK, and pSTAT3/STAT3 were evaluated by ELISA. Additionally, cardiac mirR-21 and miR-26a were assessed. A combined administration of DOX/Trz disrupted redox and Ca2+ homeostasis in cardiac tissue induced myocardial fibrosis and myofibril loss and triggered cardiac DNA damage and apoptosis. This cardiotoxicity was accompanied by decreased NRG-1 mRNA expression, HER2 protein expression, and suppressed AKT and ERK phosphorylation, while triggering JNK phosphorylation. Histological and ultra-structural examination of cardiac specimens revealed features typical of cardiac tissue injury. Moreover, a significant decline in cardiac function was observed through biochemical testing of serum cardiac markers and echocardiography. In contrast, the intraperitoneal administration of MSCs-derived exosomes alleviated cardiac injury in both protective and curative protocols; however, superior effects were observed in the protective protocol. The results of the current study indicate the ability of MSCs-derived exosomes to protect from and attenuate DOX/Trz-induced cardiotoxicity. The NRG-1/HER2, MAPK, PI3K/AKT, PJNK/JNK, and PSTAT/STAT signaling pathways play roles in mediating these effects.

Potential protective effect of catechin on doxorubicin-induced cardiotoxicity in adult male albino rats

Doxorubicin (DOX) is the most effective and frequently used anticancer drug but its cardiotoxicity is the most important side effect that limits the clinical use of it. This study was designed to investigate the protective role of catechin (CAT) on DOX induced cardiotoxicity. Rats were randomly divided into three groups. Group (I) served as the control. Group (II) served as toxic group, (1.66 mg/kg; i.p.). Group (III) served as protective group, was pretreated with (400 mg CAT/kg; p.o.) for 2 weeks then received DOX with CAT for 12 days. In the present study, administration of DOX induced significant (p < 0.001) reductions in cardiac tissue level of reduced glutathione (GSH) and activities of antioxidant enzymes (catalase, superoxide dismutase (SOD), and glutathione-S- transferase (GST)). Moreover, it resulted in a significant (p < 0.001) increase in cardiac tissue concentrations of nitric oxide (NO), H2O2 and malondialdehyde (MDA) as well as serum levels of cardiac injury biomarkers (lactate dehydrogenase (LDH), creatine kinase (CK), and creatine kinase-MB (CK-MB)) which were reversed by treatment with CAT. DOX administration induced the loss of myofibrils, hemorrhage, and congested blood vessels. Ultrastructural results revealed loss of myofibrils and intercalated disks and mitochondrial degeneration. All histopathological alterations were reversed by the treatment with CAT. Catechin, as an antioxidant, showed protective effects against DOX cardiotoxicity via reducing lipid peroxidation, inflammation, and alleviating apoptosis.

Commentary: "Postoperative Changes in Left Ventricular Systolic Function after Combined Mitral and Aortic Valve Replacement in Patients with Rheumatic Heart Disease" Sang-Mee An, MD, Jae-Sik Nam, MD, Ho Jin Kim, MD, PhD, Hyeun Joon Bae, MD, Ji-Hyun Chin, MD, PhD, Eun-Ho Lee, MD, PhD, In-Cheol Choi, MD, PhD.

It is an elegant albeit limited study reporting effects of pre op LVEF on long term results in patients with RHD undergoing DVR. Study includes 146 patients out of 201 who underwent DVR in the study period. Although all had some improvement immediate post op, those with preserved ejection fraction (EF) and smaller left ventricles regardless of type of prostheses used, surgical techniques (partial or full Subvalvular Apparatus Preservation), had more sustained improvement after 3-4 years than those with lower EF and more dilation. It can be partially explained by more prevalence of aortic insufficiency in patients with pre op lower EF <50 and dilation (average left ventricular end systolic dimension 49 vs. 32 mm in EF >50). There are myocardial factors which also play a part, those with abnormal left ventricle (LV) function have more extensive loss of myofibrils either due to disproportion of mitochondria-to-myofibril ratio or myofibrillar degeneration exhibiting the extent RHD involves myocardium. Structural adaptation may not all be just a result of hemodynamic abnormalities in these patients. The recommendation that surgical intervention should occur before the LV starts to dilate or EF drops is well founded and would be impactful in the developing world, an estimated 250,000 deaths occur annually worldwide and 10.5 million disability adjusted life years due to RHD, mostly in young people.

Cardioprotective potential of melatonin, quercetin and resveratrol in an experimental model of diabetes

ABSTRACT Oxygen radicals participate in the pathogenesis of heart damage. Diabetes accelerates the formation of reactive oxygen species (ROS). We investigated the effects of the antioxidants, melatonin, quercetin and resveratrol, on cardiomyopathy and apoptosis in rats with streptozotocin (STZ) induced diabetes mellitus (DM). Rats were divided into five groups of seven: control, DM, DM + melatonin, DM + quercetin and DM + resveratrol. All treatments were begun with a single dose of STZ to induce diabetes and experimental treatments were continued daily for 30 days. Morphologic and apoptotic changes were analyzed by histological assessment. The heart tissue of the control group exhibited normal histology, whereas the heart tissue of the DM group exhibited vacuolization, necrosis, congestion, infiltration and myofibril loss. The DM group exhibited significantly increased apoptosis compared to the control group. Differences in anti-apoptotic effects were statistically significant for all three antioxidant treatment groups; the anti-apoptotic effects of quercetin and resveratrol were similar. Melatonin, resveratrol and quercetin exhibited protective effects against diabetic heart damage.

Left Atrial Remodeling Mechanisms Associated with Atrial Fibrillation.

Heart disease has always been one of the important diseases that endanger health and cause death. Therefore, it is particularly important to understand left atrium reconstruction and atrial fibrillation before heart image processing. The purpose of this paper is to provide an important review of the mechanisms of left atrial remodeling (LAR) associated with atrial fibrillation (AF). LAR refers to the spectrum of pathophysiological changes in (i) atrial structure and physiological function, and (ii) electric, ionic, and molecular milieu of the LA, in response to stresses imposed by conditions such as hypertension, myocardial ischemia, autonomic denervation and congestive heart failure. The main mechanisms of LAR include electrical remodeling, structural remodeling, metabolic remodeling, autonomic remodeling, neurohormones and inflammation, and other influencing factors. LAR is not only the basic mechanism of AF and heart failure, but also the pathophysiological basis of its progression. In clinical practice, AF is the most common persistent arrhythmia, and is believed to be the result of a combination of mechanisms that have triggers and maintenance mechanisms, including spontaneous ectopic pacing and multiple wavelet reentry. While LA electrophysiological, structural, and ultra-structural changes trigger AF, in turn, AF alters the LA electrical and structural properties that promote its maintenance and recurrence. Chronic AF leads to extensive changes in atrial cellular substructures, including loss of myofibrils, accumulation of glycogen, changes in mitochondrial shape and size, fragmentation of sarcoplasmic reticulum, and dispersion of nuclear chromatin. Electrical remodeling and structural remodeling of the atria during AF, involving structural changes and functional impairment of the left atrium, can lead to serious decline in left ventricular function and severe heart failure. Therefore, LAR and AF are inter-activating phenomena, and the resulting complications can cause serious disabling and fatal events. In this paper, we present (i) the mechanisms of LAR, in the form of structural, electrical, metabolic, and neurohormonal changes, and (ii) their interactive roles in initiating and maintaining AF. These in-depth understanding of the atrial remodeling mechanisms can in turn provide useful insights into the treatment of AF and heart failure.

Combined Microscopic and Metabolomic Approach to Characterize the Skeletal Muscle Fiber of the Ts65Dn Mouse, A Model of Down Syndrome

Down syndrome (DS) is a genetically based disease caused by triplication of chromosome 21. DS is characterized by severe muscle weakness associated with motor deficits; however, understanding the DS-associated skeletal muscle condition is limited. In this study, we used a combined methodological approach involving light and electron microscopy, as well as nuclear magnetic resonance spectroscopy metabolomics, to investigate morphology and composition of the quadriceps muscles in the Ts65Dn mouse, a model of DS, to identify structural and/or functional trisomy-associated alterations. Morphometric analysis demonstrated a larger size of myofibers in trisomic versus euploid mice; however, myofibrils were thinner and contained higher amounts of mitochondria and lipid droplets. In trisomic mice, magnetic resonance spectroscopy showed a tendency to an overall increase in muscle metabolites involved in protein synthesis. These data strongly suggest that in DS, a sarcoplasmic hypertrophy associated with myofibril loss characterizes quadriceps myofibers. In addition, large-sized mitochondria suggestive of impaired fission/fusion events, as well as metabolites modifications suggestive of decreased mitochondrial function, were found in the trisomic muscle. Albeit preliminary, the results provided by this novel approach consistently indicate structural and compositional alterations of the DS skeletal muscle, which are typical of early aging.

Prospective Evaluation of Clinico-Pathological Predictors of Postoperative Atrial Fibrillation: An Ancillary Study From the OPERA Trial.

Postoperative atrial fibrillation (POAF) occurs in 30% to 50% of patients undergoing cardiac surgery and is associated with increased morbidity and mortality. Prospective identification of structural/molecular changes in atrial myocardium that correlate with myocardial injury and precede and predict risk of POAF may identify new molecular pathways and targets for prevention of this common morbid complication. Right atrial appendage samples were prospectively collected during cardiac surgery from 239 patients enrolled in the OPERA trial (Omega-3 Fatty Acids for Prevention of Post-Operative Atrial Fibrillation), fixed in 10% buffered formalin, and embedded in paraffin for histology. We assessed general tissue morphology, cardiomyocyte diameters, myocytolysis (perinuclear myofibril loss), accumulation of perinuclear glycogen, interstitial fibrosis, and myocardial gap junction distribution. We also assayed NT-proBNP (N-terminal pro-B-type natriuretic peptide), hs-cTnT, CRP (C-reactive protein), and circulating oxidative stress biomarkers (F2-isoprostanes, F3-isoprostanes, isofurans) in plasma collected before, during, and 48 hours after surgery. POAF was defined as occurrence of postcardiac surgery atrial fibrillation or flutter of at least 30 seconds duration confirmed by rhythm strip or 12-lead ECG. The follow-up period for all arrhythmias was from surgery until hospital discharge or postoperative day 10. Thirty-five percent of patients experienced POAF. Compared with the non-POAF group, they were slightly older and more likely to have chronic obstructive pulmonary disease or heart failure. They also had a higher European System for Cardiac Operative Risk Evaluation and more often underwent valve surgery. No differences in left atrial size were observed between patients with POAF and patients without POAF. The extent of atrial interstitial fibrosis, cardiomyocyte myocytolysis, cardiomyocyte diameter, glycogen score or Cx43 distribution at the time of surgery was not significantly associated with incidence of POAF. None of these histopathologic abnormalities were correlated with levels of NT-proBNP, hs-cTnT, CRP, or oxidative stress biomarkers. In sinus rhythm patients undergoing cardiac surgery, histopathologic changes in the right atrial appendage do not predict POAF. They also do not correlate with biomarkers of cardiac function, inflammation, and oxidative stress. Graphic Abstract: A graphic abstract is available for this article.

Identification of KIAA0196 as a novel susceptibility gene for myofibril structural disorganization in cardiac development

BackgroundCongenital heart disease is one of the most common cardiac malformation-related diseases worldwide. Some causative genes have been identified but can explain only a small proportion of all cases; therefore, the discovery of novel susceptibility genes and/or modifier genes for abnormal cardiac development remains a major challenge. MethodsWe used a single nucleotide polymorphism (SNP) array, and next-generation sequencing (NGS) was conducted to screen and quickly identify candidate genes. KIAA0196 knockout zebrafish and mice were generated by CRISPR/Cas9 to detect whether or how KIAA0196 deficiency would influence cardiac development. ResultsHomozygous, but not heterozygous, zebrafish and mice showed early embryonic lethality. At the embryonic stage, microscopic examination and dissection revealed pericardial edema and ventricle enlargement in homozygous zebrafish and obviously delayed cardiac development in heterozygous mice, while echocardiography and tissue staining showed that significantly decreased cardiac function, ventricle enlargement, myofibril loss, and significantly reduced trabecular muscle density were observed in adult heterozygous zebrafish and mice. Most importantly, immunostaining and electron microscopy showed that there was a significant increase in sarcomere structural disorganization and myofibril structural integrity loss in KIAA0196 mutants. Furthermore, substantial downregulation in other sarcomeric genes and proteins was detected and verified in a mouse model via transcriptome and proteomics analyses; these changes especially affected the myosin heavy or light chain (MYH or MYL) family genes. ConclusionWe identified KIAA0196 for the first time as a susceptibility gene for abnormal cardiac development. KIAA0196 deficiency may cause abnormal heart development by influencing the structural integrity of myofibrils.

Vitamin A administration in lizards during tail regeneration determines epithelial mucogenesis and delays muscle and cartilage differentiation.

Regenerating epidermis and spinal cord is essential to maintain tail regeneration in lizards. The effects of vitamin A, an inhibitor of epithelial cornification, have been studied in lizards during tail regeneration. The injection of high doses of vitamin A induces regeneration of a thinner tail with gummy consistency and suppression of the formation of a normal cartilaginous axial skeleton. Microscopic analysis reveals that all epithelia increase the secretion of glycoprotein-mucus. During the analyzed period the epidermis does not form scales and keratinocytes limit or stop the production of bundles of intermediate filament keratins and packets of corneous beta-proteins (β-keratins). Differentiation of oberhautchen and β-layers is much reduced or inhibited while α-keratinization and the formation of a corneous layer are affected as well. The effects of vitamin A are dramatic also on mesoderm cells since the treatment stimulates an invasion of blood cells likely due to the disruption of the wall of blood vessels, mesenchymal cell death (pycnosis), and diffuse phagocytosis by immune cells. A delay of cartilage differentiation and cartilage degradation due to an increase of lysosomes in these cells or released by white blood cells explains the lack of stiffness of the regenerating tail after vitamin A treatment. Regenerating muscles are variably affected, ranging from a variable necrotic effect with partial degradation of internal organelles and myofilaments to a massive or complete loss of myofibrils that do not organize in sarcomeres. In general hypervitaminosis A appears to delay epithelial but also mesodermal cell differentiation and maintains the regenerating tail in an immature condition.

Exosome Treatment Enhances Anti-Inflammatory M2 Macrophages and Reduces Inflammation-Induced Pyroptosis in Doxorubicin-Induced Cardiomyopathy.

Doxorubicin (Dox) is an effective antineoplastic agent used to treat cancers, but its use is limited as Dox induces adverse cardiotoxic effects. Dox-induced cardiotoxicity (DIC) can lead to heart failure and death. There is no study that investigates whether embryonic stem cell-derived exosomes (ES-Exos) in DIC can attenuate inflammation-induced pyroptosis, pro-inflammatory M1 macrophages, inflammatory cell signaling, and adverse cardiac remodeling. For this purpose, we transplanted ES-Exos and compared with ES-cells (ESCs) to examine pyroptosis, inflammation, cell signaling, adverse cardiac remodeling, and their influence on DIC induced cardiac dysfunction. Therefore, we used C57BL/6J mice ages 10 ± 2 weeks and divided them into four groups (n = 6–8/group): Control, Dox, Dox + ESCs, and Dox + ES-Exos. Our data shows that the Dox treatment significantly increased expression of inflammasome markers (TLR4 and NLRP3), pyroptotic markers (caspase-1, IL1-β, and IL-18), cell signaling proteins (MyD88, p-P38, and p-JNK), pro-inflammatory M1 macrophages, and TNF-α cytokine. This increased pyroptosis, inflammation, and cell signaling proteins were inhibited with ES-Exos or ESCs. Moreover, ES-Exos or ESCs increased M2 macrophages and anti-inflammatory cytokine, IL-10. Additionally, ES-Exos or ESCs treatment inhibited significantly cytoplasmic vacuolization, myofibril loss, hypertrophy, and improved heart function. In conclusion, for the first time we demonstrated that Dox-induced pyroptosis and cardiac remodeling are ameliorated by ES-Exos or ESCs.

P3793Spironolactone in patients with permanent atrial fibrillation, possible heart failure protective potential

Abstract Background Atrial fibrillation (AF) promotes electrical, neurohormonal and structural remodeling of atria and ventricles. Long lasting AF leads to atrial interstitial fibrosis, apoptosis, loss of myofibrils and finally to heart failure (HF). Purpose The aim of the study was impact of aldosterone antagonist, spironolactone, on exercise tolerance and neurohormonal activity in patients with permanent AF without symptoms of HF. Methods In prospective, randomized study patients with permanent AF at least for 1 year, no signs and symptoms of HF and stable clinical condition were included. Patients were randomized to: beta-blocker plus spironolactone (dose: 25 mg) treatment and rate-control treatment with only beta-blocker. Propranolol, metoprolol and bisoprolol were used, doses were adjusted to achieve resting heart rate 60–80/min. Ergospirometry (CPX) and 6-minute walk (6-MWT) tests were performed during separate days. Results Study group consisted of 49 patients, 69% men, mean age 62.1±9.6 without structural and chronic active diseases, mean time of arrhythmia was 5.5 years, Q1: 2, Q3: 8 years. Follow-up was 11.2 months. All patients were treated with beta-blockers, 27 patients were treated with 25 mg spironolactone. Surprisingly physical capacity in 6-minute walk test (6-MWT) in studied patients was not significantly reduced in comparison with values ranges for healthy volunteers. After 11.2 months follow-up significantly longer exercise time (433±113 vs. 367±162 sec, p&lt;0.05) and lower maximal HR (159±25 vs. 165±22 beats/min, p&lt;0.0550) were observed in spironolactone treated group. Other CPX variables did not differ significantly between groups after 11,2 months: VO2: 20.7±5.1 vs. 20.1±4.8 [ml/kg/min]; VO2 as % of normal value: 78.4±15.2 vs. 76.8±15.2; O2 pulse: 12±2.8 vs. 12.7±3.6 [ml/beat]; AT: 1.4±0.3, 1.6±0.5 [L/min]; VE: 74.9±20.0, 72.6±17.9 [L/min]. All spirometric variables worsened after 11.2 months: VC: 4.3±1.1 vs. 3.8±0.8 [L], p&lt;0.0005, FVC: 4.2±1.1 vs. 3.8±1.0 p&lt;0.005 [L], FEV1: 3.1±0.8 vs. 2.8±0.7 [L], p&lt;0.01. In spironolactone treated group after 11.2 months BNP concentrations were significantly lower: Q1: 54, Q2: 83, Q3: 100 vs. Q1: 42, Q2: 93; Q3: 184 ng/L (p=0.025) and aldosterone levels were markedly increased: Q1: 216, Q2: 266; Q3:443 vs. Q1: 169; Q2: 228; Q3:294 ng/dL (p=0.0007). Conclusions In patients with permanent atrial fibrillation cardiopulmonary exercise responses were markedly abnormal, but exercise capacity was increased after spironolactone treatment. Deterioration of spirometry results might be due to beta-blocker treatment. In spironolactone treated group BNP levels were significantly lower what may correspond to its heart failure protective activity.

Cardioprotective effect of caffeic acid phenethyl ester on cardiac contusion following blunt chest trauma in rats

ABSTRACTWe investigated the effects of caffeic acid phenethyl ester (CAPE) on cardiac damage after blunt chest injury. Forty male adult Wistar albino rats were divided into four groups; control, cardiac contusion, cardiac contusion + CAPE, and CAPE. CAPE, 10 mmol/kg, was administered intraperitoneally for 7 days following cardiac contusion. Heart tissue and blood were obtained at the end of the experimental period. Cardiac histopathology was determined using hematoxylin & eosin (H & E) staining. Expression of tumor necrosis factor-alpha (TNF-α) in cardiomyocytes was determined using immunohistochemistry. Cardiac apoptosis was determined using the TUNEL method. Serum creatine kinase (CK), creatine kinase-muscle/brain (CK-MB) and lactate dehydrogenase (LDH) levels were determined using spectrophotometric methods. The serum cardiac troponin I (C-TI) level was measured using the ELISA method. Myofibril loss was detected in the cardiomyocytes of the cardiac contusion group. Increased apoptosis and TNF-α expression were observed in the cardiac contusion group compared to the control group. Increased CK, CK-MB, LDH and C-TI levels were found in the cardiac contusion group. We found that CAPE administration improved myocardial function. Compared to the cardiac contusion group, CK, CK-MB, LDH and C-TI levels decreased significantly in the cardiac contusion + CAPE group. Administration of CAPE significantly inhibited apoptosis and cardiac TNF-α expression. Our findings demonstrate the therapeutic effects of CAPE for cardiac contusion damage after blunt chest trauma.

Keeping the Heart Fitm2 during Chemotherapy.

Keeping the Heart Fitm2 during Chemotherapy.