Bone Marrow Cells ; cytology ; Fibroblasts ; cytology ; metabolism ; Fibrosis ; Humans ; Myocardium ; pathology

Cardiac autophagy dramatically increases in heart failure induced by sustained pressure overload. However, it has not yet been addressed if enhanced autophagy plays a role in protecting myocardium or mediating progression from compensative hypertrophy to heart failure. The aim of the present study was to detect autophagic flux of cardiomyocytes from 20-week transverse abdominal aortic constriction (TAC) rats. Fasting rats were used as the positive control for detecting cardiac autophagy. Echocardiography was applied to find the changes of cardiac structure and function. Immunofluorescent histochemistry and Western blot were used to analyze the related biomolecular indexes reflecting cardiac autophagic flux. After the previous methods for detecting cardiac autophagy were confirmed, the autophagic flux in cardiomyocytes of rats subjected to 20-week TAC was examined. The results showed that fasting had no obvious influence on parameters of cardiac structure in rats, including interventricular septal wall thickness and left ventricle posterior wall thickness, but heart rate, diastolic left ventricle internal dimension, fractional shortening of left ventricle dimension, ejection fraction and mitral inflow velocity decreased in rats after fasting for 3 d. Meanwhile, positively stained particles of LC3 and cathepsin D, but not ubiquitin and complement 9, distributed within cardiomyocytes of 3-day fasting rats, indicating augmented autophagic flux. Compared with sham rats, 20-week TAC rats did not show any changes of LC3, cathepsin D, ubiquitin and complement 9 in myocardium detected by immunofluorescent histochemistry. In addition, protein levels of LC3, cathepsin D and p62 in myocardium of TAC rats did not changed. These results reveal the unchanged autophagic flux in cardiomyocytes at middle or late phase of cardiac hypertrophy in TAC rats, implying a balance between inhibition of hypertrophy and activation of pressure load stress on autophagy.
Animals ; Aorta ; pathology ; Autophagy ; Cardiomegaly ; physiopathology ; Constriction ; Heart ; physiopathology ; Myocardium ; pathology ; Myocytes, Cardiac ; cytology ; Rats

OBJECTIVETo study the effects of skeletal muscle satellite cells implanted into infarcted myocardium on the volume of remnant myocytes.

METHODSThirty-six adult mongrel canines were divided randomly into implantation group and control group. In the implantation group, skeletal muscle satellite cells taken from the gluteus maximus muscles of the dogs were cultured, proliferated and labeled with 4',6-diamidino-2-phenylindone (DAPI) in vitro. In both groups, a model of acute myocardial infarction was established in every dog. In the implantation group, each dog was injected with M199 solution containing autologous skeletal muscle satellite cells. The dogs in the control group received M199 solution without skeletal muscle satellite cells. The dogs of both groups were killed 2, 4 and 8 weeks after implantation (six dogs in a separate group each time). Both infarcted myocardium and normal myocytes distal from the infracted regions isolated were observed under optical and fluorescent microscope. Their volumes were determined using a confocal microscopy image analysis system and analyzed using SAS. A P < 0.05 was considered significant.

RESULTSA portion of the implanted cells differentiated into muscle fiber with striations and were connected with intercalated discs. Cross-sectional area and cell volume were increased in normal myocardium. Hypertrophy of remnant myocytes in the infarcted site after skeletal muscle cell implantation was much more evident than in the control group. Cross-sectional area, cell area and cell volume differed significantly from those of the control group (P < 0.05). Hypertrophy of the cells occurred predominantly in terms of width and thickness, whereas cell length remained unchanged.

CONCLUSIONSkeletal muscle satellite cells implanted into infarct myocardium, could induce the hypertrophy of remnant myocyte cells in the infarcted site and could also aid in the recovery of the contractile force of the infarcted myocardium.

Animals ; Cell Size ; Dogs ; Myocardial Infarction ; pathology ; Myocardium ; pathology ; Myocytes, Cardiac ; cytology ; Random Allocation ; Satellite Cells, Skeletal Muscle ; cytology ; physiology

OBJECTIVETo study the effect of different access routes on autologous satellite cell implantation to stimulate myocardial regeneration.

METHODSSatellite cells were procured from skeletal muscle (gluteus max) of adult mongrel canine, cultured, proliferated and labeled with 4', 6-diamidino-2-phenylindone (DAPI) in vitro. The cells were autologously implanted into the site of acute myocardial infarction by local injection or perfusion through the ligated distal left anterior descending coronary artery. Specimens were harvested 2, 4 and 8 weeks later for histological study.

RESULTSThe labeling efficiency of satellite cells with DAPI was close to 100%. Fluorescent cells were found at the infarcted zone, papillary muscle and local injection site. Some of these cells had progressively differentiated into striated muscle fibers connected to intercalated discs. The infant cells appeared different from the mature myocardium under an electron microscope. Satellite cells implanted by perfusion through the coronary artery were arranged in order of consistency with host myocardial fibers. The satellite cells, implanted by local injection, were found growing in a disordered way.

CONCLUSIONSatellite cells, implanted by coronary artery perfusion, can progressively differentiate into striated muscle fibers, arranging in order and disseminating over the infarcted zone. This approach seems more favorable for the recovery of myocardial contractile function than that of local injection.

Animals ; Cell Differentiation ; physiology ; Dogs ; Myocardial Infarction ; pathology ; therapy ; Myocardium ; cytology ; Regeneration ; Satellite Cells, Skeletal Muscle ; cytology ; transplantation ; Transplantation, Autologous

OBJECTIVETo study the histopathologic features, differential diagnosis and pathogenesis of diabetic cardiomyopathy.

METHODSThe clinicopathologic features of 40 autopsy cases of diabetes mellitus were studied. The hearts from another 40 cases of non-diabetic elderly deceased were used for comparison.

RESULTSIn the 40 cases of diabetes studied, 36 cases (90.0%) showed microscopic myocardial cell death. Focal interstitial fibrosis was observed in 37 cases (92.5%). On the other hand, similar myocardial cell death and patchy interstitial fibrosis was seen in 8 cases (20.0%) and 9 cases (22.5%) of non-diabetic hearts, respectively. The difference between the two groups was statistically significant (P < 0.01). The mural thickness of intramyocardial blood vessels was significantly increased in diabetic group (20.6 microm +/- 4.2 microm) than in non-diabetic group (7.2 microm +/- 5.2 microm), P < 0.01.The myocardial changes in diabetic group however were similar to those in non-diabetic group with systemic hypertension.

CONCLUSIONSPathologic diagnosis of diabetic cardiomyopathy relies on detailed histologic examination of heart tissue and clinical correlation of a long history of diabetes mellitus. Exclusion of other possible etiologies is also essential. The myocardial cell death observed may be due to the ischemic effect induced by diabetic microangiopathy in cardiac muscle.

Aged ; Aged, 80 and over ; Autopsy ; Cardiomyopathies ; complications ; diagnosis ; Cell Death ; Coronary Vessels ; cytology ; pathology ; Diabetes Complications ; pathology ; Diagnosis, Differential ; Female ; Fibrosis ; diagnosis ; pathology ; Humans ; Male ; Myocardium ; cytology ; pathology

OBJECTIVETo simulate and assess the clinical effect of intracoronary infusion of bone marrow mononuclear cells or peripheral endothelial progenitor cells on myocardial reperfusion injury in mini-swine model.

METHODSTwenty-three mini-swine with myocardial reperfusion injury were used as designed in the study protocol. About (3.54 +/- 0.90) x 10(8) bone marrow mononuclear cells (MNC group, n = 9) or (1.16 +/- 1.07) x 10(7) endothelial progenitor cells (EPC group, n = 7) was infused into the affected coronary segment of the swine. The other mini-swine were infused with phosphate buffered saline as control (n = 7). Echocardiography and hemodynamic studies were performed before and 4 weeks after cell infusion. Myocardium infarction size was calculated. Stem cell differentiation was analyzed under a transmission electromicroscope.

RESULTSLeft ventricular ejection fraction dropped by 0% in EPC group, 2% in MNC group, and 10% in the control group 4 weeks after cell infusion, respectively (P < 0.05). The systolic parameters increased in MNC and EPC groups but decreased in the control group. However, the diastolic parameters demonstrated no significant change in the three groups (P > 0.05). EPC decreased total infarction size more than MNC did (1.60 +/- 0.26 cm2 vs. 3.71 +/- 1.38 cm2, P < 0.05). Undermature endothelial cells and myocytes were found under transmission electromicroscope.

CONCLUSIONSTransplantation of either MNC or EPC may be beneficial to cardiac systolic function, but might not has obvious effect on diastolic function. Intracoronary infusion of EPC might be better than MNC in controlling infarction size. Both MNC and EPC may stimulate angiogenesis, inhibit fibrogenesis, and differentiate into myocardial cells.

Animals ; Bone Marrow Cells ; cytology ; Bone Marrow Transplantation ; Cell Differentiation ; Endothelial Cells ; cytology ; Myocardial Reperfusion Injury ; pathology ; therapy ; Myocardium ; pathology ; Stem Cells ; cytology ; Swine ; Swine, Miniature

Objective: To explore the predictive value of neutrophil/lymphocyte ratio (NLR) on myocardial injury in severe COVID-19 patients. Methods: In this single-center retrospective cohort study, we collected and analyzed data form 133 severe COVID-19 patients admitted to Renmin Hospital of Wuhan University (Eastern District) from January 30 to February 18, 2020. Patients were divided into myocardial injury group (n=29) and non-myocardial injury group (n=104) according the presence or absence of myocardial injury. The general information of patients was collected by electronic medical record database system. All patients were followed up for 30 days, the organ injury and/or dysfunction were monitored, the in-hospital death was compared between the two groups, and the disease progression was reevaluated and classified at 14 days after initial hospitalization. Logistic regression analysis was performed to identify risk factors of myocardial injury in severe COVID-19 patients. The ROC of NLR was calculated, and the AUC was determined to estimate the optimal cut-off value of NLR for predicting myocardial injury in severe cases of COVID-19. Results: There was statistical significance in age, respiratory frequency, systolic blood pressure, symptoms of dyspnea, previous chronic obstructive pulmonary disease, coronary heart disease history, white blood cells, neutrophils, lymphocytes, platelets, C-reactive protein, platelet counting, aspartate transaminase, albumin, total bilirubin, direct bilirubin, urea, estimated glomerular filtration rate, total cholesterol, low-density lipoprotein cholesterol, D-dimer, CD3⁺, CD4⁺, partial pressure of oxygen, partial pressure of CO₂, blood oxygen saturation, other organ injury, clinical outcome and prognosis between patients with myocardial injury and without myocardial injury (all P<0.05). Multivariate logistic regression analysis showed that NLR was a risk factor for myocardial injury (OR=1.066，95%CI 1.021-1.111，P=0.033). ROC curve showed that NLR predicting AUC of myocardial injury in severe COVID-19 patients was 0.774 (95%CI 0.694-0.842), the optimal cut-off value of NLR was 5.768, with a sensitivity of 82.8%, and specificity of 69.5%. Conclusion: NLR may be used to predict myocardial injury in severe COVID-19 patients.
Betacoronavirus ; COVID-19 ; Coronavirus Infections/pathology* ; Heart Diseases/virology* ; Humans ; Lymphocytes/cytology* ; Myocardium/pathology* ; Neutrophils/cytology* ; Pandemics ; Pneumonia, Viral/pathology* ; Prognosis ; ROC Curve ; Retrospective Studies ; SARS-CoV-2

We investigated the effect of phenylephrine (PE)- and isoproterenol (ISO)-induced cardiac hypertrophy on subcellular localization and expression of caveolin-3 and STAT3 in H9c2 cardiomyoblast cells. Caveolin-3 localization to plasma membrane was attenuated and localization of caveolin-3 to caveolae in the plasma membrane was 24.3% reduced by the catecholamine-induced hypertrophy. STAT3 and phospho-STAT3 were up-regulated but verapamil and cyclosporin A synergistically decreased the STAT3 and phospho-STAT3 levels in PE- and ISO-induced hypertrophic cells. Both expression and activation of STAT3 were increased in the nucleus by the hypertrophy. Immunofluorescence analysis revealed that the catecholamine-induced hypertrophy promoted nuclear localization of pY705-STAT3. Of interest, phosphorylation of pS727-STAT3 in mitochondria was significantly reduced by catecholamine-induced hypertrophy. In addition, mitochondrial complexes II and III were greatly down-regulated in the hypertrophic cells. Our data suggest that the alterations in nuclear and mitochondrial activation of STAT3 and caveolae localization of caveolin-3 are related to the development of the catecholamine-induced cardiac hypertrophy.
Animals ; Catecholamines/*pharmacology ; Caveolae/*metabolism ; Caveolin 3/*metabolism ; Cell Line ; Hypertrophy/metabolism ; Mitochondria/*metabolism ; Myocardium/cytology/*pathology ; Myocytes, Cardiac/cytology/*drug effects/metabolism ; Rats ; STAT3 Transcription Factor/*metabolism

OBJECTIVETo explore the pathogenic changes of myocardial apoptosis in heart hypertrophy during hypertension and evaluate the anti-apoptosis effect of Valsartan.

METHODSThirty spontaneously hypertensive rats (SHRs) were divided into two groups: 15 treated with Valsartan (20 mg x kg(-1) x d(-1)) (SHR + Valsartan group), the others with placebo (SHR + placebo group), with 15 normal Wistar rats as control. Systolic blood pressure was measured by the tail-cuff method. The observation period was from 8 to 16 weeks of age. Cardiac apoptosis was evaluated by a Terminal Deoxynucleotidyl Transferase-Mediated dUTP-biotin Nick End Labeling (TUNEL) assay.

RESULTSMean blood pressure values were 127 +/- 2 mm Hg in controls, 163 +/- 6 mm Hg in the SHR + Valsartan group and 193 +/- 7 mm Hg in the SHR + placebo group at 16 weeks of age, whereas the blood pressure in 8-week-old SHR and Wistar rats were 175 +/- 3 mm Hg and 125 +/- 5 mm Hg, respectively. The ratio of the heart weight over body weight declined in Wistar (3.07 +/- 0.03 mg/g) and SHR + Valsartan groups (3.22 +/- 0.19 mg/g) compared with the SHR + placebo group (4.02 +/- 0.31 mg/g) (P < 0.05). The density of TUNEL-positive cells in Wistar and SHR +/- Valsartan groups was 23.3 +/- 3.3 nuclei/HPF and 35.0 +/- 1.3 nuclei/HPF, both of which were significantly less than that of the SHR + placebo group (116.7 +/- 11.3 nuclei/HPF).

CONCLUSIONSIn response to chronic pressure overload, cardiomyocyte-specific apoptosis contributes to the transition from compensatory hypertrophy to decompensation. Apoptosis may be effectively inhibited by Valsartan in the early stage of hypertension.

Animals ; Antihypertensive Agents ; pharmacology ; Apoptosis ; drug effects ; Cardiomegaly ; pathology ; Hypertension ; pathology ; Myocardium ; cytology ; Rats ; Rats, Inbred SHR ; Rats, Wistar ; Tetrazoles ; pharmacology ; Valine ; analogs & derivatives ; pharmacology ; Valsartan

OBJECTIVETo investigate the feasibility of in vitro and in vivo magnetic resonance imaging (MRI) and fluorescence imaging tracking of transplanted bone mesenchymal stem cells (BMSCs) dual-labeled with ultrasmall superparamagnetic iron oxide (USPIO) and red fluorescence protein (RFP).

METHODSBMSCs were incubated with culture medium containing USPIO for 24 hours. The Prussian-blue staining, transmission electron microscopy and trypan-blue staining were used to study the efficacy and safety of labeling. F344 rat model of acute myocardial infarction was established by ligating the left anterior descending coronary artery. The dual-labeled BMSCs were injected into the margin of the infraction myocardium. Then MRI and fluorescence imaging were performed to trace the cells both in vitro and in vivo. Postmortal study was carried out to observe the distribution of transplanted cells in myocardium.

RESULTSThe percentage of dual-labeled BMSCs reached 99% after co-incubating with USPIO for 24 hours. USPIO particles were mainly located in lysosomes. As demonstrated by trypan-blue staining, there was no significant deference in viability between labeled and unlabeled groups (P>0.05). All dual-labeled transplanted BMSCs showed a significant decreasing signal on MRI, and the signal intensity changes had no significant difference over 4 weeks (P=0.66). In vitro cell tracing with fluorescence imaging of isolated heart from F344 rats was successful,while in vivo cell tracing with fluorescence imaging failed. Prussian blue staining showed that USPIO distributed near the infarcted myocardium, corresponding with the fluorescence imaging.

CONCLUSIONMRI can be used to trace the dual-labeled BMSCs transplanted into F344 rat hearts in vivo, while fluorescence imaging and pathological fluorescence imaging can trace the transplanted cells in vitro.

Animals ; Bone Marrow Cells ; cytology ; Cells, Cultured ; Dextrans ; Disease Models, Animal ; Fluorescent Antibody Technique ; Magnetic Resonance Imaging ; Magnetite Nanoparticles ; Mesenchymal Stem Cell Transplantation ; Mesenchymal Stromal Cells ; cytology ; Myocardial Infarction ; surgery ; Myocardium ; cytology ; pathology ; Rats ; Rats, Inbred F344