Cardiomyocyte Degeneration Research Articles

Asphyxiation by inhaling the inert gas helium inside a plastic bag

А case of death from asphyxiation by inhaling the inert gas helium inside a plastic bag placed over the head.
 Findings and discussion. In our practice, we had a case of post-mortem examination of a 22 y.o. male. As it is known from the circumstances of the case, the mail corpse was found in a forest belt area, with his head inside a black plastic bag tight-fitted around his neck with a band. In the bag, there were two plastic tubes – one of them was placed obliquely at the level of right anterior surface of neck and was fixed to the neck with transparent adhesive tape. The other end of tube was connected to the outlet of a valve on a cylinder of brown color superscribed «HELIUM». The valve of a cylinder was opened. The other tube is located on the left side of the neck, with a rubber ball attached to the exposed end.
 On post-mortem examination, we found the following: face – pale, not congested, w/o petechiation; livor mortis – generalized dark purple discoloration of the skin. Findings on internal examination: congestion of internal organs; dark-red liquid blood inside the cardiac cavity and larger vessels; hemicardiadextra, SVC and IVC overfilled with blood. No hemorrhages under epicardium and pleura.
 Findings during microscopic examination of internal organs: Heart: lack of arterial blood, venous congestion. Albuminous degeneration of cardiomyocytes. Interstitial edema. Areas of dystelectasis, acute vesicular emphysema. Pulmonary congestion.
 Liver: irregular blood filling of tissue. Albuminous degeneration, destruction of hepatocellular cytoplasm. Interstitial edema. Kidney: cortical ischemia, congestion of straight venules. Albuminous degeneration in nephrothelium of convoluted tubules. Interstitial edema. Brain: irregular blood filling of cerebral vessels. In pia mater: edema&focal infiltrates of fresh RBCs. Focal voids surrounding the vessels and neurons. Ischemic degeneration of neurons. Red blood cells accumulations in the enlarged paravasal spaces. Suprarenal gland: irregular venous congestion of tissue; occasional thinning of adrenal cortex. Pancreatic gland: lack of arterial blood, venous congestion. Spleen: irregular blood filling of tissue. Decision: morphological signs of acute death. Pulmonary edema. Forensic toxicology test results: methyl, ethyl, isopropyl, butyl, isoamyl alcohol; barbiturates; opium alkaloids – morphine, codeine and their synthetic analogues; phenothiazine, benzodiazepine derivatives; ephedrine, ephedrone – have not been identified.
 Conclusion: As can be seen from the above, the results of forensic examination of corpse, forensic toxicology and forensic histology tests, with account being taken of circumstances and scene investigation details, allowed suggesting that the possible cause of death was the asphyxiation by inhaling the inert gas helium inside a plastic bag placed over the head.

Human umbilical cord mesenchymal stem cells alleviate interstitial fibrosis and cardiac dysfunction in a dilated cardiomyopathy rat model by inhibiting TNF‑α and TGF‑β1/ERK1/2 signaling pathways.

Dilated cardiomyopathy (DCM) is a disease of the heart characterized by pathological remodeling, including patchy interstitial fibrosis and degeneration of cardiomyocytes. In the present study, the beneficial role of human umbilical cord-derived mesenchymal stem cells (HuMSCs) derived from Wharton's jelly was evaluated in the myosin-induced rat model of DCM. Male Lewis rats (aged 8-weeks) were injected with porcine myosin to induce DCM. Cultured HuMSCs (1×106 cells/rat) were intravenously injected 28 days after myosin injection and the effects on myocardial fibrosis and the underlying signaling pathways were investigated and compared with vehicle-injected and negative control rats. Myosin injections in rats (vehicle group and experimental group) for 28 days led to severe fibrosis and significant deterioration of cardiac function indicative of DCM. HuMSC treatment reduced fibrosis as determined by Masson's staining of collagen deposits, as well as quantification of molecular markers of myocardial fibrosis such as collagen I/III, profibrotic factors transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), and connective tissue growth factor (CTGF). HuMSC treatment restored cardiac function as observed using echocardiography. In addition, western blot analysis indicated that HuMSC injections in DCM rats inhibited the expression of TNF-α, extracellular-signal regulated kinase 1/2 (ERK1/2) and TGF-β1, which is a master switch for inducing myocardial fibrosis. These findings suggested that HuMSC injections attenuated myocardial fibrosis and dysfunction in a rat model of DCM, likely by inhibiting TNF-α and the TGF-β1/ERK1/2 fibrosis pathways. Therefore, HuMSC treatment may represent a potential therapeutic method for treatment of DCM.

Capillary Degeneration and Right Ventricular Remodeling Due to Hypoxic Stress with Sugen5416.

Sugen5416 (semaxinib) is an inhibitor of the vascular endothelial growth factor (VEGF) receptor. A rat model of Pulmonary Arterial Hypertension (PAH), created with Sugen5416 and chronic hypoxia, is known to have similar histological findings to those of PAH patients. To evaluate the pathophysiological mechanisms of cardiac remodeling due to hypoxic stress with Sugen5416 in vivo. Male Sprague-Dawley rats were exposed to hypoxia (10 ± 1% O2) for 2 weeks after a single injection of Sugen5416 (SU-hypoxia group) or the vehicle (V-hypoxia group). Hypoxia elevated right ventricular (RV) systolic pressure and caused RV remodeling on Day 14. By electron microscopy, metamorphosis of capillaries with endothelial cell occlusive degeneration was observed in the RV myocardium of the SU-hypoxia group from Day 3. After reoxygenation, progressive RV remodeling with extensive degeneration of cardiomyocytes was observed in the SUhypoxia group, associated with a significant increase of oxidative stress and TUNEL-positive cells in both RV and left ventricular myocardium on Day 84. The expression of VEGF mRNA in the RV myocardium was significantly suppressed in the SU-hypoxia group on Day 3, whereas delayed activation of VEGF/extracellular signal-regulated kinase (ERK) signaling pathway on Day 14 were observed. Capillary degeneration and activation of VEGF/ERK signaling pathway might be crucial to accelerate the cardiac remodeling due to hypoxic stress with Sugen5416.

Ultrastructural aspects of vacuolar degeneration of cardiomyocytes in human endomyocardial biopsies.

Vacuolar degeneration of cardiomyocytes is a histological finding commonly encountered during routine light microscopic examination of human endomyocardial biopsy specimens. The vacuoles appear as intracellular clear areas lacking myofibers. By itself, this finding has little diagnostic value, but may have important clinical implications when the vacuolar contents are of etiological significance (e.g., accumulation of abnormal metabolites), and the clinical importance is increased when the disease is treatable. Thanks to its great resolving power, electron microscopy can often reveal the contents of the vacuoles and lead to a correct diagnosis. It can be used to differentially diagnose lysosomal storage diseases such as Fabry, Danon, and Pompe disease, doxorubicin cardiomyopathy, mitochondrial cardiomyopathy, autophagic degeneration, and accumulation of subcellular organelles (mitochondria, lipofuscin, glycogen granules, endoplasmic reticulum, etc.) as a nonspecific finding in failing cardiomyocytes. Nonetheless, undiagnosed cases certainly remain. It is strongly recommended that small pieces of tissue samples be fixed for electron microscopy at every endomyocardial biopsy procedure, and electron microscopic examination should be performed when a marked vacuolar degeneration is found.

Activation of the E3 ligase Cbl by Neutrophil Cathepsin G Impairs CXC chemokine receptor 4 Signaling in Cardiomyocyte Degeneration.

ObjectiveInflammatory cells and their proteases contribute to tissue repair at the site of inflammation. Although beneficial in the early stage, excessive inflammation leads to cell death and tissue damage. Increasing evidence demonstrates the role of inflammatory cells and their proteases in cardiac remodeling during the progression to heart failure; however the mechanisms by which inflammation contribute to myocyte death and subsequent alteration in the geometry and mechanical properties of the heart are still largely unknown. Therefore, we hypothesized that neutrophil‐derived protease Cat.G regulates CXC chemokine receptor (CXCR) 4 protein stability and turnover in myocytes through activation of Casitas b‐lineage lymphoma (c‐Cbl), an adaptor protein with an intrinsic E3 ubiquitin ligase activity.Methods and ResultsWe have previously shown that neutrophil serine protease Cat.G promotes cardiomyocyte death through c‐Cbl activation and interaction with tyrosine receptors that result in their ubiquitination and degradation. We next assessed whether Cbl activation was involved in CXCR4 signaling downregulation and myocyte apoptosis secondary to exposure of Cat.G. Acute stimulation with Cat.G (5 min to 30 min) induced CXCR4 phosphorylation along with its interaction with Cbl. However, chronic stimulation with Cat.G (1–4hrs) increased both CXCR4 ubiquitination and degradation. Inhibition of the ubiquitin proteasome system, with MG132 or lactacystin, or adenoviral expression of dominant negative mutant Cbl significantly reduced CXCR4 degradation induced by Cat.G. In contrast, adenoviral expression of wild type Cbl enhanced CXCR4 ubiquitination and degradation in response to Cat.G. Restoration of CXCR4 signaling, by adenoviral expression of CXCR4, attenuated CXCR4 downstream signaling downregulation, myofibril degeneration and myocyte apoptosis induced by Cat.G.ConclusionThese data support a model in which neutrophil derived serine proteases promote c‐Cbl interaction with CXCR4 protein, resulting in enhanced c‐Cbl‐mediated CXCR4 protein degradation, myofibril degradation and subsequent down‐regulation of myocyte survival signaling.

Significance and Value of Endomyocardial Biopsy Based on Our Own Experience.

Endomyocardial biopsy (EMB) has been established in parallel with the development of percutaneous catheter technology for the diagnosis of cardiac diseases. It was developed in the early 1960 s in Japan by Drs. Konno, Sakakibara and Sekiguchi of Tokyo Women's Medical University. EMB is a valuable and useful, but invasive, modality for making a definite diagnosis in diseases such as myocarditis and secondary cardiomyopathies, which are often difficult to diagnose by imaging modality alone. In the field of heart transplantation, the histology of EMB helps monitor rejection to allografts. In cases of chronic heart failure, fibrosis and degeneration of cardiomyocytes are very important findings of heart remodeling. Recently, molecular biology technology has been applied to EMB specimens to get more detailed information. However, we must also recognize that EMB is an invasive examination that should not be performed without skillful cardiac catheterization experience to avoid complications. In this review as a message from pathologists, we present key cardiac histopathology using EMB, in a way that allows one to imagine whole cardiac pathological conditions. We also describe the current role of EMB and its significance in order to encourage young cardiologists to perform EMB to see another world of pathology.

From the Cover: Investigative Nonclinical Cardiovascular Safety and Toxicology Studies with BMS-986094, an NS5b RNA-Dependent RNA Polymerase Inhibitor.

BMS-986094, a 2'-C-methylguanosine prodrug that was in development for treatment of chronic hepatitis C infection was withdrawn from Phase 2 clinical trials because of unexpected cardiac and renal adverse events. Investigative nonclinical studies were conducted to extend the understanding of these findings using more comprehensive endpoints. BMS-986094 was given orally to female CD-1 mice (25 and 150 mg/kg/d) for 2 weeks (53/group) and to cynomolgus monkeys (15 and 30 mg/kg/d) for up to 6 weeks (2-3/sex/group for cardiovascular safety, and 5/sex/group for toxicology). Endpoints included toxicokinetics; echocardiography, telemetric hemodynamics and electrocardiography, and tissue injury biomarkers (monkey); and light and ultrastructural pathology of heart, kidney, and skeletal muscle (mouse/monkey). Dose-related and time-dependent findings included: severe toxicity in mice at 150 mg/kg/d and monkeys at 30 mg/kg/d; decreased left ventricular (LV) ejection fraction, fractional shortening, stroke volume, and dP/dt; LV dilatation, increased QTc interval, and T-wave flattening/inversion (monkeys at ≥ 15 mg/kg/d); cardiomyocyte degeneration (mice at 150 mg/kg/d and monkeys at ≥ 15 mg/kg/d) with myofilament lysis/myofbril disassembly; time-dependent proteinuria and increased urine β-2 microglobulin, calbindin, clusterin; kidney pallor macroscopically; and tubular dilatation (monkeys); tubular regeneration (mice 150 mg/kg/d); and acute proximal tubule degeneration ultrastructurally (mice/monkeys); and skeletal muscle degeneration with increased urine myoglobin and serum sTnI. These studies identified changes not described previously in studies of BMS-986094 including premonitory cardiovascular functional changes as well as additional biomarkers for muscle and renal toxicities. Although the mechanism of potential toxicities observed in BMS-986094 studies was not established, there was no evidence for direct mitochondrial toxicity.

Pathological manifestations of acute-stage radioactive myocardial damage and related mechanisms

Objective To investigate the pathological manifestations of acute-stage radioactive myocardial damage and related mechanisms using an experimental animal model. Methods A total of 12 adult male Sprague-Dawley rats were randomly divided into control group and radiation group. In the radiation group, the model of radiation-induced myocardial damage was established by the irradiation of the anterior myocardial territory with 6-MV X-ray at a single dose of 20 Gy, and at 14 days after irradiation, HE staining was used to observe the morphological changes of cardiomyocytes and intercellular matrix, and Masson staining was used to observe the distribution of collagen fibers. The collagen volume fraction (CVF) was used for semi-quantitative analysis. ELISA was used to measure the activity of total superoxide dismutase (T-SOD) and the concentration of malondialdehyde (MDA), and Western blot was used to measure the expression of the fibrosis marker protein collagen type I (COL-1) and the endoplasmic reticulum stress-related proteins GRP78 and CHOP. The t-test, t’-test, or nonparametric rank sum test was used for comparison between groups. Results At 14 days after local irradiation of the heart, the radiation group had disordered arrangement of cardiomyocytes, marked edema, rupture of some cardiomyocytes, mild karyopyknosis in cardiomyocytes, and infiltration of inflammatory cells in the myocardial interstitium, compared with the control group. Collagen fibers in the myocardial tissue were mainly distributed in the perivascular area and cardiomyocyte interstitium. The radiation group had a significantly higher CVF than the control group (11.35% vs. 5.23%, P=0.000) and a significant increase in the expression of COL-1 compared with the control group (P=0.000). The radiation group had significant increases in the activity of T-SOD and the concentration of MDA in the myocardial tissue compared with the control group (T-SOD: 156.61 U/mgprot vs. 137.06 U/mgprot, P=0.042; MDA: 2.36 nmol/mgprot vs. 1.31 U/mgprot, P=0.007). Compared with the control group, the radiation group showed significant increases in the expression of endoplasmic reticulum stress-related proteins GRP78 and CHOP (P=0.037 and 0.009). Conclusions The pathological manifestations of acute-stage myocardial damage include degeneration of cardiomyocytes, inflammatory exudation in the interstitium, and deposition of collagen in the perivascular area and myocardial interstitium. Myocardial fibrosis can be observed in the acute stage of radiation-induced myocardial damage, and the mechanism may be related to oxidative stress and endoplasmic reticulum stress induced by radioactive rays. Key words: Radiation induced heart disease; Histopathology; Fibrosis; Oxidative stress; Endoplasmic reticulum stress

МІКРОСКОПІЧНІ ЗМІНИ В ЛЕГЕНЯХ І СЕРЦІ СОБАК, ЩО ЗАГИНУЛИ ЗА ДИРОФІЛЯРІОЗУ, СПРИЧИНЕНОГО DIROFILARIA IMMITIS

Dirofilariosis – invasive parasitic disease which can be fatal. Specific course of the disease is the lack of visible signs of the disease at an early stage and make the complexity of diagnosing the disease is especially dangerous, as pet owners may not be aware of what their favorite animal is ill. Until now, according to statistics, dirofilariosis diagnosed by chance during examination before surgery, or carrying out tests for reasons far from suspected dirofilariosis.Dirofilariosis registered in Africa, Asia and Southern Europe. In the United States established endemic areas where there have been outbreaks of helminthiasis annually. The cases were registered in the UK, Sweden, the Netherlands, Austria, Hungary, Bulgaria, Romania, Germany, Poland, Russia, Kazakhstan, the republics of the North Caucasus. Now dirofilariosis observed in Kiev, Odessa, Kharkiv, Kyiv, Chernihiv, Sumy, Poltava, Kharkiv and other areas. Today dirofilariosis carnivores and man registered on the territory of 37 states.Numerous published data indicate that most dirofilariosis in the countries of the former Soviet Union caused by two pathogen – Dirofilaria immitis and Dirofilaria repens.D. repens parasite in the subcutaneous tissue. Another kind of – D. immitis – in the heart, the lungs, the pulmonary artery and other vessels carnivores. Sometimes these nematodes parasitize in unusual places (the brain, the bronchioles, the abdominal cavity, eyes).Dirofilariosis problem for Ukraine is very urgent, because, firstly, the disease among dogs acquires the character of enzootic, secondly, the increase in the number of different types of vectors of infection, in the third, increasing the area of distribution – from the tropics to temperate regions, in the fourth, the difficulties in diagnosis disease and, fifthly, there is lack of training and educational and propaganda work among the population.The aim of our research was to a deeper and more complete definition of the features of microscopic changes in dog heartworm.We used the results of histological examination of samples of pathological material taken from 6 different breeds of dogs that suffered from heartworm. Autopsy was performed by the method of partial evisceration. Microscopic studies were carried out according to conventional techniques.In carrying out investigations following changes were microscopically established: in the lungs – seen interstitial pneumonia, venous hyperemia, hemorrhage, and also discovered microfilariae in the lumen of blood vessels and interstitial tissue. In the myocardium – granular and fatty degeneration, necrosis and destruction of cardiomyocytes in blood vessels – single microfilariae.

Cardiomyocyte-specific conditional knockout of the histone chaperone HIRA in mice results in hypertrophy, sarcolemmal damage and focal replacement fibrosis.

ABSTRACTHIRA is the histone chaperone responsible for replication-independent incorporation of histone variant H3.3 within gene bodies and regulatory regions of actively transcribed genes, and within the bivalent promoter regions of developmentally regulated genes. The HIRA gene lies within the 22q11.2 deletion syndrome critical region; individuals with this syndrome have multiple congenital heart defects. Because terminally differentiated cardiomyocytes have exited the cell cycle, histone variants should be utilized for the bulk of chromatin remodeling. Thus, HIRA is likely to play an important role in epigenetically defining the cardiac gene expression program. In this study, we determined the consequence of HIRA deficiency in cardiomyocytes in vivo by studying the phenotype of cardiomyocyte-specific Hira conditional-knockout mice. Loss of HIRA did not perturb heart development, but instead resulted in cardiomyocyte hypertrophy and susceptibility to sarcolemmal damage. Cardiomyocyte degeneration gave way to focal replacement fibrosis and impaired cardiac function. Gene expression was widely altered in Hira conditional-knockout hearts. Significantly affected pathways included responses to cellular stress, DNA repair and transcription. Consistent with heart failure, fetal cardiac genes were re-expressed in the Hira conditional knockout. Our results suggest that transcriptional regulation by HIRA is crucial for cardiomyocyte homeostasis.

Clinical significance of endomyocardial biopsy in conjunction with cardiac magnetic resonance imaging to predict left ventricular reverse remodeling in idiopathic dilated cardiomyopathy.

Endomyocardial biopsy (EMB) and cardiac magnetic resonance (CMR) are useful modalities to study the characteristics of myocardial tissue. However, the prognostic impact of both diagnostic tools to predict subsequent left ventricular reverse remodeling (LVRR) has not been well elucidated. A total of 187 consecutive patients with idiopathic dilated cardiomyopathy (IDCM) who were treated by optimal pharmacotherapy (OPT) and underwent EMB of the LV wall were investigated. The myocardial specimens were semiquantitatively evaluated measuring cardiomyocyte degeneration (CD), interstitial fibrosis (IF), and hypertrophy. In addition, late gadolinium enhancement (LGE)-CMR was performed in 78 (48%) patients. Seventy-eight (48%) patients developed LVRR, defined as a ≥10% increase in LV ejection fraction with a ≥10% decrease in indexed LV end-diastolic dimension at 12months after OPT. Multivariate regression analysis revealed that CD (P=0.003), but not IF (P=0.320), was an independent predictor of LVRR. In the patients with not only EMB but also CMR, the CD score and LGE area were independent predictors of LVRR (odds ratios/P values 0.268/0.010, 0.855/<0.001, respectively). The patients with mild CD and negative LGE had a better achievement rate of LVRR than those with severe CD and positive LGE (74 vs. 19%). A combination of CD score on EMB and LGE-CMR is useful to predict subsequent LVRR in IDCM patients.

Immunopathological Features of Canine Myocarditis Associated with Leishmania infantum Infection.

Myocarditis associated with infectious diseases may occur in dogs, including those caused by the protozoa Neospora caninum, Trypanosoma cruzi, Babesia canis, and Hepatozoon canis. However, although cardiac disease due to Leishmania infection has also been documented, the immunopathological features of myocarditis have not been reported so far. The aim of this study was to examine the types of cellular infiltrates and expression of MHC classes I and II in myocardial samples obtained at necropsy from 15 dogs with an established intravitam diagnosis of visceral leishmaniasis. Pathological features of myocardium were characterized by hyaline degeneration of cardiomyocytes, necrosis, and infiltration of mononuclear inflammatory cells consisting of lymphocytes and macrophages, sometimes with perivascular pattern; fibrosis was also present in various degrees. Immunophenotyping of inflammatory cells was performed by immunohistochemistry on cryostat sections obtained from the heart of the infected dogs. The predominant leukocyte population was CD8+ with a fewer number of CD4+ cells. Many cardiomyocytes expressed MHC classes I and II on the sarcolemma. Leishmania amastigote forms were not detected within macrophages or any other cell of the examined samples. Our study provided evidence that myocarditis in canine visceral leishmaniasis might be related to immunological alterations associated with Leishmania infection.

Experimental North American West Nile Virus Infection in the Red-legged Partridge (Alectoris rufa)

After the introduction of West Nile virus (WNV) into North America, bird mortalities associated with West Nile disease have dramatically increased in this continent and, to a lesser extent, in Europe. The different West Nile disease incidence in birds in these 2 continents demands an explanation, and experimental studies can provide important information. The authors inoculated thirteen 9-week-old red-legged partridges (Alectoris rufa) with 10(7)plaque-forming units of a WNV strain isolated in New York in 1999. The objective was to study the pathogenesis of the infection in a native Euro-Mediterranean bird species with a WNV strain known to be highly pathogenic for numerous native American bird species. Additionally, the authors evaluated the dynamics of inflammatory cell activation and recruitment into the brain. WNV was detected in tissues 3 days postinoculation (dpi), and the birds developed macroscopic and microscopic lesions. Two partridges succumbed to the disease. The most affected tissues were the heart, brain, and spinal cord. The main microscopic findings were the presence of mononuclear infiltrates in the heart and brain, gliosis, and degeneration and necrosis of cardiomyocytes and neurons. These lesions were aggravated in the birds that died or were euthanized 7 dpi or later. In the brain, there was an upregulation of microglial cells and astrocytes and an increase in the number of T cells, especially after 7 dpi. These results show that this WNV strain is of moderate virulence for the red-legged partridge and that WNV-infected red-legged partridges develop an immune cell response in the brain similar to that of mammals.

Value of cardiac magnetic resonance imaging in the setting of familiar cardiomyopathy: A step toward pre-clinical diagnosis

A 24-years-old asymptomatic man was referred to our Institution for screening of familiar idiopathic dilated cardiomyopathy (CMP) due to the important family history of dilated CMP with associated severe burden of ventricular arrhythmias (Fig. 1). His father and a first-degree father's cousin were indeed both affected by idiopathic dilated CMP, which was diagnosed in their third decade after an episode of sustained ventricular tachycardia (VT); both underwent implantable cardioverter defibrillator (ICD) implantation for secondary prevention of sudden cardiac death (SCD) and subsequently experienced multiple appropriate ICD interventions. Due to further dilatation and dysfunction of the left ventricle (LV) and worsening of the arrhythmic burden as well as heart failure symptoms despite optimal medical therapy, they were finally referred to heart transplantation at the age of 40 and 45 years, respectively. In addition, two more first-degree father's cousins died suddenly at the age of 14 and 47 years. The histologic examination of the explanted heart of proband's father showed multiple areas of dense fibrosis with intra-myocardial and sub-epicardial patchy distribution (Fig. 2A –B, Mallory trichromic stain: blue areas); myocyte apoptotic and degenerative phenomena were also observed (Fig. 2C–D, arrows). Of note, a strong family history of breast cancer was also present in the family (Fig. 1). Fig. 2Cardiomyopathy-related myocardial morphological changes are shown in histological sections of the explanted heart of the proband's father. They consist of a spectrum of changes beginning with focal degeneration and necrosis of cardiomyocytes with no or minimal cellular response, followed by myofiber loss and replacement of the cardiomyocytes with varying degrees of fibrosis. Low magnification shows intra-myocardial (A) and sub-epicardial (B) areas of dense fibrotic scar with patchy distribution (blue with Mallory trichromic stain). Higher magnification reveals foci of myocardial degeneration with vacuolization of cardiomyocytes (panel C–D, arrows, Hematoxylin and Eosin stain). Necrotic cardiomyocytes exhibit homogeneously brightly eosinophilic sarcoplasm with pyknotic or karyorrhectic nuclei (panels C–D, arrows). View Large Image Figure Viewer Download Hi-res image

Cardiovascular protection by ezetimibe and influence on oxidative stress in mice exposed to intermittent hypoxia

Ezetimibe is as an inhibitor of NPC1L1 protein, which has a key role in cholesterol absorption. The aim of this study was to evaluate the influence of ezetimibe on the plasma lipid profile, atherosclerotic lesions, and cardiomyocyte ultrastructure in an animal model of atherosclerosis with intermittent hypoxia. Apolipoprotein E-knockout mice received a high-fat diet for 30 days. Then animals were exposed to intermittent hypoxia for 10 days or were maintained under normoxic conditions. In the ezetimibe group, ezetimibe (5mg/kg/day) was added to the diet. Under normoxic conditions, the total cholesterol level was significantly lower in the ezetimibe group (63.6±6.6mg/dl) than in the control group (116.3±16.9mg/dl, P<0.001). Intermittent hypoxia accelerated atherosclerosis associated with increased superoxide production, which also caused degeneration of cardiomyocytes, mitochondrial abnormalities, and interstitial fibrosis. Compared with the control group, the ezetimibe group showed significantly less advanced atherosclerotic lesions and lower superoxide production in the thoracic aorta, as well as reduced oxidative stress, preservation of cardiomyocyte ultrastructure, and reduced interstitial fibrosis in the left ventricular myocardium. In conclusion, ezetimibe not only reduces total cholesterol, but also prevents the development of atherosclerosis and cardiovascular events due to intermittent hypoxia at least partly through suppression of oxidative stress.

Therapeutic effects of pentoxifylline on diabetic heart tissue via NOS.

Objective:Diabetes mellitus causes a decrease in cardiac output, arterial blood pressure, and heart rate. In this study, we aimed to investigate, at the molecular level, the effect of nitric oxide synthase (NOS) on heart pathology in type 1 diabetes and look at the therapeutic effect of pentoxifylline on this pathology.Methods:In this experimental study, 50 Wistar albino male rats were used. The rats were divided into 5 groups: group C, control; group D, only diabetes; group D+PI and D+PII, diabetes + pentoxifylline; group P, only pentoxifylline. Group D+PI rats received 50 mg/kg/day pentoxifylline over two months. However, group D+PII rats received saline in the first month and 50 mg/kg/day of pentoxifylline over the following month. At the end of two months, NOS expressions in heart tissue were assessed through immunohistochemistry analysis. The data were compared by one-way ANOVA.Results:At the end of the experiments, there was increased cytoplasmic vacuolization, myofibrillar loss, cytoplasmic eosinophilia, and degeneration of cardiomyocytes; nNOS and iNOS expressions in group D decreased compared with that in group C. In group D+PI and group D+PII, nNOS and iNOS expressions improved compared with group D.Conclusion:As a result, we found that diabetes, a known chronic disease, causes serious damage in heart tissue. NOS plays a role in this damage, and pentoxifylline aided in improving nNOS and iNOS expression in this damage.

Abstract 47: Expression of Galectin-3 in the Myocardium and Arterial Walls of Kawasaki Disease Patients

Background: Although coronary artery aneurysms are the most significant complication of Kawasaki Disease (KD), histologic examination has revealed myocarditis and myocardial fibrosis (MF) in most cases. Galectin-3 (Gal-3) is a matricellular protein that plays a multifunctional role in inflammation, fibrosis, and cell differentiation. It is a prognostic indicator of heart failure and cardiovascular events. Gal-3 plays a role in adhesion and migration of inflammatory and fibroblastic cells. We previously reported that plasma Gal-3 levels were elevated in acute pediatric KD and adult KD with giant aneurysms (GA). We postulated that Gal-3 may be involved in both acute inflammation and convalescent fibrosis in KD. Methods: Conventional H&amp;E staining, Trichrome staining and immunohistochemical analysis for Gal-3 were performed on 1 acute stage KD subject and 10 convalescent stage KD hearts including 6 from subjects with GA and 4 from subjects without aneurysms who died of non-cardiovascular causes. Results: In the acute KD myocardium, round inflammatory cells were seen infiltrating the myocardium and positive staining for Gal-3 was noted. In the myocardium of convalescent KD with GA, widespread cardiomyocyte degeneration and necrosis with extensive bridging fibrosis were observed but inflammatory cells were not detected; spindle-shaped cells expressing Gal-3 in the cytoplasm were observed between cardiomyocytes. Myocardial fibrosis and Gal-3 expression were not observed in the myocardium of KD subjects without aneurysms. In the acute KD coronary arteries, Gal-3 positive inflammatory cells were observed in all layers, and the intima was already thickened by illness day 7. Destruction of the internal elastic lamina and intimal thickening with Gal-3-positive spindle-shaped cells were observed in coronary and systemic arteries of convalescent KD subjects. Conclusion: Gal-3 expression was related to inflammation in acute KD and tissue fibrosis in late convalescent KD with GA. Elevated levels of Gal-3 should raise concern for MF in KD patients with GA. However, in KD without aneurysms, myocardial fibrosis and Gal-3 expression were not observed; therefore myocarditis in KD patients with normal coronary arteries may improve without progression to MF.

0161: The neuroprotective agent rasagiline mesylate attenuates cardiac remodeling after experimental myocardial infarction

Rasagiline, (R) mesylate (N-propargyl-1 (R)-aminoindan) is a selective, potent irreversible inhibitor of MAO-B with neuroprotective and anti-apoptotic properties. We investigated whether R could provide cardioprotection in a 6 month Wistar male rat model (350-400gr) undergoing experimental Myocardial Infarction (MI). MI was induced surgically by a permanent ligation of the left anterior descending coronary artery. We included 3 experimental groups: R (n=10), Control (C) (n=10), and sham-operated (S) (n=10). R was administered daily (2 mg/kg i.p.) for 4 weeks, beginning 24 hours after MI induction. Group C received normal saline 0.9%, i.p. Cardiac function was assessed by two-dimensional targeted M-mode echocardiography (Vivid 7, 13MHz), at baseline, 14 and 28 days post MI. Estimation of cardiac remodeling and cardiomyocyte damage was performed by immuno-fluorescent microscopy analysis. Baseline measurements were similar in all groups. Group R showed less FS (%) deterioration vs group C at 14 (31.4±2.1 vs 22.3±2.0, p<0.0001) and 28 days (31.6±2.3vs19.6±1.8, p<0.0001). Immuno-fluorescent microscopy analysis of the infract border zone indicated reduced collagen I staining in group R (n=3) rats compared to group C (n=3) and less cardiomyocyte degeneration as indicated by b-catenin and desmin staining. Also, apoptosis (TUNEL) was reduced by 65% in the border zone and 58% in the remote region of R treated animals. Importantly, scar size did not differ among the two groups. Our study showed attenuation in cardiac remodelling after MI as presented by better systolic function in Rasagiline mesylate (a commonly used neurological drug) treated rats accompanied by less border zone fibrosis and cardiomyocyte degeneration indicating a beneficial effect in the post-MI period.

Myocarditis in dogs: etiology, clinical and histopathological features (11 cases: 2007-2013).

BackgroundMyocarditis is a disease caused by numerous etiological factors and characterized by a non-specific course. The only method allowing for precise characterization of inflammatory changes is the histopathological examination of heart muscle specimens. The study was conducted on heart muscle preparations from 11 dogs with ante-mortem diagnosis of cardiac disease. Animals presented with a poor response to an applied treatment or had suspected sudden cardiac death. The heart specimens were taken post-mortem, preserved and stained with haematoxylin and eosin. Subsequently, the presence and intensity of changes, i.e. inflammatory infiltration, the amount of connective tissue and features of cardiomyocyte degeneration were estimated. The specimens from dogs suspected of having a myocarditis of bacteriological etiology underwent additional bacteriological and immunohistochemical examination.ResultsThe examination revealed an inflammatory infiltration of variable intensity combined with the degenerative changes in all dogs. There were vegetative and abnormal cystic forms of Borrelia burgdorferi sensu lato in 6 dogs. A Staphylococcus aureus infection was confirmed in one dog and an acute coronary syndrome with neutrophil infiltration was revealed in another one.ConclusionsAlthough the clinical pattern in patients with myocarditis is diverse, the definitive morphological diagnosis is made based on the histopathological examination. This examination can lead to a better understanding of the pathogenesis of the disease. To the best of our knowledge, this is the first description of myocarditis combined with the presence of spore forms of Borrelia burgdorferi sensu lato in the heart specimens of dogs.Electronic supplementary materialThe online version of this article (doi:10.1186/s13620-014-0028-8) contains supplementary material, which is available to authorized users.

Arrhythmogenic cardiomyopathy: a disease of intercalated discs.

Arrhythmogenic cardiomyopathy (ACM) is an acquired progressive disease having an age-related penetrance and showing clinical manifestations usually during adolescence and young adulthood. It is characterized clinically by a high incidence of severe ventricular tachyarrhythmias and sudden cardiac death and pathologically by degeneration of ventricular cardiomyocytes with replacement by fibro-fatty tissue. Whereas, in the past, the disease was considered to involve only the right ventricle, more recent clinical studies have established that the left ventricle is frequently involved. ACM is an inherited disease in up to 50% of cases, with predominantly an autosomal dominant pattern of transmission, although recessive inheritance has also been described. Since most of the pathogenic mutations have been identified in genes encoding desmosomal proteins, ACM is currently defined as a disease of desmosomes. However, on the basis of the most recent description of the intercalated disc organization and of the identification of a novel ACM gene encoding for an area composita protein, ACM can be considered as a disease of the intercalated disc, rather than only as a desmosomal disease. Despite increasing knowledge of the genetic basis of ACM, we are just beginning to understand early molecular events leading to cardiomyocyte degeneration, fibrosis and fibro-fatty substitution. This review summarizes recent advances in our comprehension of the link between the molecular genetics and pathogenesis of ACM and of the novel role of cardiac intercalated discs.