Skeletal muscle derived Musclin protects the heart during pathological overload.

Cachexia is associated with poor prognosis in chronic heart failure patients, but the underlying mechanisms of cachexia triggered disease progression remain poorly understood. Here, we investigate whether the dysregulation of myokine expression from wasting skeletal muscle exaggerates heart failure. RNA sequencing from wasting skeletal muscles of mice with heart failure reveals a reduced expression of Ostn, which encodes the secreted myokine Musclin, previously implicated in the enhancement of natriuretic peptide signaling. By generating skeletal muscle specific Ostn knock-out and overexpressing mice, we demonstrate that reduced skeletal muscle Musclin levels exaggerate, while its overexpression in muscle attenuates cardiac dysfunction and myocardial fibrosis during pressure overload. Mechanistically, Musclin enhances the abundance of C-type natriuretic peptide (CNP), thereby promoting cardiomyocyte contractility through protein kinase A and inhibiting fibroblast activation through protein kinase G signaling. Because we also find reduced OSTN expression in skeletal muscle of heart failure patients, augmentation of Musclin might serve as therapeutic strategy.

RADIOTHERAPY-ASSOCIATED CARDIOVASCULAR COMPLICATIONS IN CANCER (review). / SERTsEVO-SUDYNNI USKLADNENNIa, ASOTsIIOVANI Z PROMENEVOIu TERAPIIeIu (ogliad literatury).

The review is devoted to the current issues of radiation-induced cardiovascular complications, their diagnostics andincidence depending on the radiation doses and exposure regimens, potential efficiency of the screening strategiesfor cardiotoxicity monitoring after radiotherapy in cancer patients by analyzing the data from literature and clinical trials, based on recommendations of European Society of Cardiology and European Society of Medical Oncology.

Regenerative Potential of a Suspension and Spheroids of Multipotent Mesenchymal Stromal Cells from Human Umbilical Cord on the Model of Myocardial Infarction in Rats.

Regenerative potential of multipotent mesenchymal stromal cells from the human umbilical cord (MMSC-UC) in the suspension and spheroid form was revealed during the progression of experimental small focal myocardial infarction in rats. In isoproterenol-induced myocardial infarction, foci of necrosis and inflammatory infiltrate and at later terms fibrosis foci were found mainly in the left ventricle of rat heart. In rats receiving MMSC-UC, destructive changes in the myocardium, fibrous scars, and inflammatory process were less pronounced. MMSC-UC also contributed to normalization of the morphofunctional parameters of the heart. Spheroids exhibited higher efficiency in comparison with cell suspension.

Molecular, Cellular, and Clinical Evidence That Sodium-Glucose Cotransporter 2 Inhibitors Act as Neurohormonal Antagonists When Used for the Treatment of Chronic Heart Failure.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of cardiovascular death and hospitalization for heart failure in patients with chronic heart failure. Initially, these drugs were believed to have a profile similar to diuretics or hemodynamically active drugs, but they do not rapidly reduce natriuretic peptides or cardiac filling pressures, and they exert little early benefit on symptoms, exercise tolerance, quality of life, or signs of congestion. Clinically, the profile of SGLT2 inhibitors resembles that of neurohormonal antagonists, whose benefits emerge gradually during sustained therapy. In experimental models, SGLT2 inhibitors produce a characteristic pattern of cellular effects, which includes amelioration of oxidative stress, mitigation of mitochondrial dysfunction, attenuation of proinflammatory pathways, and a reduction in myocardial fibrosis. These cellular effects are similar to those produced by angiotensin converting enzyme inhibitors, ß-blockers, mineralocorticoid receptor antagonists, and neprilysin inhibitors. At a molecular level, SGLT2 inhibitors induce transcriptional reprogramming of cardiomyocytes that closely mimics that seen during nutrient deprivation. This shift in signaling activates the housekeeping pathway of autophagy, which clears the cytosol of dangerous cytosolic constituents that are responsible for cellular stress, thereby ameliorating the development of cardiomyopathy. Interestingly, similar changes in cellular signaling and autophagic flux have been seen with inhibitors of the renin-angiotensin system, ß-blockers, mineralocorticoid receptor antagonists, and neprilysin inhibitors. The striking parallelism of these molecular, cellular, and clinical profiles supports the premise that SGLT2 inhibitors should be regarded as neurohormonal antagonists when prescribed for the treatment of heart failure with a reduced ejection fraction.

Modulation of the acute defence reaction by eplerenone prevents cardiac disease progression in viral myocarditis.

AIMS: Left ventricular (LV) dysfunction in viral myocarditis is attributed to myocardial inflammation and fibrosis, inducing acute and long-time cardiac damage. Interventions are not established. On the basis of the link between inflammation, fibrosis, aldosterone, and extracellular matrix regulation, we aimed to investigate the effect of an early intervention with the mineralocorticoid receptor antagonist (MRA) eplerenone on cardiac remodelling in a murine model of persistent coxsackievirus B3 (CVB3)-induced myocarditis. METHODS AND RESULTS: SWR/J mice were infected with 5 × 104 plaque-forming units of CVB3 (Nancy strain) and daily treated either with eplerenone (200 mg/kg body weight) or with placebo starting from Day 1. At Day 8 or 28 post infection, mice were haemodynamically characterized and subsequently sacrificed for immunohistological and molecular biology analyses. Eplerenone did not influence CVB3 load. Already at Day 8, 1.8-fold (P < 0.05), 1.4-fold (P < 0.05), 3.2-fold (P < 0.01), and 2.1-fold (P < 0.001) reduction in LV intercellular adhesion molecule 1 expression, presence of monocytes/macrophages, oxidative stress, and apoptosis, respectively, was observed in eplerenone-treated vs. untreated CVB3-infected mice. In vitro, eplerenone led to 1.4-fold (P < 0.01) and 1.2-fold (P < 0.01) less CVB3-induced cardiomyocyte oxidative stress and apoptosis. Furthermore, collagen production was 1.1-fold (P < 0.05) decreased in cardiac fibroblasts cultured with medium of eplerenone-treated vs. untreated CVB3-infected HL-1 cardiomyocytes. These ameliorations were in vivo translated into prevention of cardiac fibrosis, as shown by 1.4-fold (P < 0.01) and 2.1-fold (P < 0.001) lower collagen content in the LV of eplerenone-treated vs. untreated CVB3-infected mice at Days 8 and 28, respectively. This resulted in an early and long-lasting improvement of LV dimension and function, as indicated by reduced LV end-systolic volume and end-diastolic volume, and an increase in LV contractility (dP/dtmax ) and LV relaxation (dP/dtmin ), respectively (P < 0.05). CONCLUSIONS: Early intervention with the MRA eplerenone modulates the acute host and defence reaction and prevents cardiac disease progression in experimental CVB3-induced myocarditis without aggravation of viral load. The findings advocate for an initiation of therapy of viral myocarditis as early as possible, even before the onset of inflammation-induced myocardial dysfunction. This may also have implications for coronavirus disease-19 therapy.

Atorvastatin Prevents Myocardial Fibrosis in Spontaneous Hypertension via Interleukin-6 (IL-6)/Signal Transducer and Activator of Transcription 3 (STAT3)/Endothelin-1 (ET-1) Pathway.

BACKGROUND Hypertension is a leading global disease, and myocardial fibrosis is an important adverse effect of hypertension, seriously threatening human health. The IL-6/STAT3 pathway and endothelin-1 (ET-1) were previously suggested to play a part in myocardial fibrosis. MATERIAL AND METHODS To investigate the role of Atorvastatin (Ato) in spontaneous hypertension, systolic blood pressure (SBP) and left ventricular mass index (LVMI) were measured, and Masson trichrome staining was performed. Furthermore, the relative protein levels of the IL-6/STAT3/ET-1 pathway were tested. RESULTS Ato prevented myocardial fibrosis in spontaneous hypertension rats, especially at the dosage of 50 mg/kg/d. The IL-6/STAT3 pathway was observed to be suppressed by Ato, and ET-1 level in myocardial tissues was also downregulated by Ato. The phosphorylation status of STAT3 was tested after Ato treatment, showing that Ato mainly stimulated the tyr-705 phosphorylation of STAT3. CONCLUSIONS Results of this study may help promote myocardial fibrosis therapy and provide insights into the IL-6/STAT3/ET-1-mediated mechanism in Ato-induced myocardial fibrosis inhibition.

Cardio-omentopexy Reduces Cardiac Fibrosis and Heart Failure After Experimental Pressure Overload.

BACKGROUND: The pedicled greater omentum has been shown to offer benefit in ischemic heart disease for both animal models and human patients. The impact of cardio-omentopexy in a pressure overload model of left ventricular hypertrophy (LVH) is unknown. METHODS: LVH was created in rats by banding the ascending aorta after right thoracotomy (n = 23). Sham surgery was performed in 12 additional rats. Six weeks after banding, surviving LVH rats were assigned to cardio-omentopexy by left thoracotomy (LVH+Om, n = 8) or sham left thoracotomy (LVH, n = 8). Sham rats also underwent left thoracotomy for cardio-omentopexy (Sham+Om, n = 6); the remaining rats underwent sham left thoracotomy (Sham, n = 6). RESULTS: Echocardiography 10 weeks after cardio-omentopexy revealed LV end-systolic diameter, cardiomyocyte diamter, and myocardial fibrosis in the LVH group were significantly increased compared with the LVH+Om, Sham+Om, and Sham groups (p < 0.01). LV ejection fraction of the LVH group was lower than the LVH+Om group (p < 0.01). Gene expression analysis revealed significantly lower levels of sarcoendoplasmic reticulum calcium adenosine triphosphatase 2b in LVH rats than in the LVH+Om, Sham+Om, and Sham groups (p < 0.01). In contrast, collagen type 1 α 1 chain, lysyl oxidase-like protein 1, nuclear protein-1, and transforming growth factor- ß1 in the LVH group were significantly higher than in the LVH+Om cohort (p < 0.01), consistent with a reduced fibrotic phenotype after omentopexy. Lectin staining showed myocardial capillary density of the LVH group was significantly lower than all other groups (p < 0.01). CONCLUSIONS: Cardio-omentopexy reduced cardiac dilation, contractile dysfunction, cardiomyocyte hypertrophy, and myocardial fibrosis, while maintaining other molecular indicators of contractile function in this LVH model.

GPR30 Attenuates Myocardial Fibrosis in Diabetic Ovariectomized Female Rats: Role of iNOS Signaling.

Premenopausal women have a reduced risk for cardiovascular disease. Estrogen deficiency augments cardiac inflammation and oxidative stress and, thereby, aggravates myocardial fibrosis (MF) and diastolic dysfunction in hypertensive female rats. However, estrogen replacement therapy has no effect on myocardial infarction and cardiac fibrosis in postmenopausal women. Further clinical studies showed that high blood glucose levels in patients with diabetes is an important cause of MF, but the underlying mechanism is unclear. To experimentally address this issue, diabetes mellitus (DM) was induced by injecting streptozotocin and administering a high-fat diet in ovariectomized (OVX) rats. High degrees of fibrosis and apoptosis were detected in the cardiac tissue of these rats, together with increased expression of iNOS. Further treatment with the G protein-coupled estrogen receptor 30 (GPR30) agonist G1 decreased iNOS expression and the apoptosis rate in cardiac tissue significantly and inhibited cardiac fibroblast (CF) proliferation. Similar trends were observed in cultured CFs treated with high concentrations of fat and glucose. In addition, treatment with the iNOS-specific inhibitor W1400 attenuated iNOS and vimentin expression, which is associated with a marked reduction in MF. These results suggest that GPR30 activation inhibits MF in diabetic OVX female rats by suppressing cardiac iNOS activity and consequently NO levels. Thus, GPR30 activation may provide novel cardioprotection strategies for postmenopausal women, especially those with DM.

MiR-18a-5p inhibits endothelial-mesenchymal transition and cardiac fibrosis through the Notch2 pathway.

Hyperglycemia plays a crucial role in the pathogenesis of diabetic complications; however, the mechanisms underlying diabetic cardiac fibrosis remain unclear. Endothelial cells are known to contribute to cardiac fibrosis through endothelial-mesenchymal transition (EndMT) under high glucose stimulation. Here we investigated the expression of miR-18a-5p and examined its functional role in human aortic valvular endothelial cells (HAVECs). Using HAVECs, we revealed that miR-18a-5p regulated high glucose-induced EndMT. Moreover, high glucose levels induced Notch2 expression, which promoted EndMT, resulting in the downregulation of vascular endothelial cadherin and CD31 and upregulation of fibroblast-specific protein-1, α-smooth muscle actin, fibronectin, and vimentin. Furthermore, Notch2 was identified as a target of miR-18a-5p. Our data showed that the overexpression of miR-18a-5p could downregulate Notch2 expression and subsequently suppress EndMT. In conclusion, our findings demonstrated that miR-18a-5p/Notch2 signaling pathway participates in the regulation of high glucose-induced EndMT, and may act as a novel promising target for myocardial fibrosis in diabetic cardiomyopathy.

Baicalin Attenuates Cardiac Dysfunction and Myocardial Remodeling in a Chronic Pressure-Overload Mice Model.

BACKGROUND/AIMS: Baicalin has been shown to be effective for various animal models of cardiovascular diseases, such as pulmonary hypertension, atherosclerosis and myocardial ischaemic injury. However, whether baicalin plays a role in cardiac hypertrophy remains unknown. Here we investigated the protective effects of baicalin on cardiac hypertrophy induced by pressure overload and explored the potential mechanisms involved. METHODS: C57BL/6J-mice were treated with baicalin or vehicle following transverse aortic constriction or Sham surgery for up to 8 weeks, and at different time points, cardiac function and heart size measurement and histological and biochemical examination were performed. RESULTS: Mice under pressure overload exhibited cardiac dysfunction, high mortality, myocardial hypertrophy, increased apoptosis and fibrosis markers, and suppressed cardiac expression of PPARα and PPARß/δ. However, oral administration of baicalin improved cardiac dysfunction, decreased mortality, and attenuated histological and biochemical changes described above. These protective effects of baicalin were associated with reduced heart and cardiomyocyte size, lower fetal genes expression, attenuated cardiac fibrosis, lower expression of profibrotic markers, and decreased apoptosis signals in heart tissue. Moreover, we found that baicalin induced PPARα and PPARß/δ expression in vivo and in vitro. Subsequent experiments demonstrated that long-term baicalin treatment presented no obvious cardiac lipotoxicity. CONCLUSIONS: The present results demonstrated that baicalin attenuates pressure overload induced cardiac dysfunction and ventricular remodeling, which would be due to suppressed cardiac hypertrophy, fibrosis, apoptosis and metabolic abnormality.

Intermedin1-53 Protects Against Myocardial Fibrosis by Inhibiting Endoplasmic Reticulum Stress and Inflammation Induced by Homocysteine in Apolipoprotein E-Deficient Mice.

AIM: Endoplasmic reticulum stress (ERS) and inflammation participate in cardiac fibrosis. Importantly, a novel paracrine/autocrine peptide intermedin1-53 (IMD1-53) in the heart inhibits myocardial fibrosis in rats. However, the mechanisms are yet to be fully elucidated. METHODS: Myocardial fibrosis in apolipoprotein E-deficient (ApoE -/-) mice and neonatal rat cardiac fibroblasts (CFs) were induced using homocysteine (Hcy). RESULTS: IMD1-53 inhibited myocardial fibrosis in vivo and in vitro. Picrosirius red staining showed that IMD1-53 reduced myocardial interstitial collagen deposition in ApoE-/- mice treated with Hcy and decreased the expression of myocardial collagen I and III, which was further verified in rat CFs. IMD1-53 attenuated myocardial hypertrophy, as shown by cardiomyocyte cross-sectional area, ratio of heart weight to body weight, and mRNA levels of atrial natriuretic peptide and brain natriuretic peptide. IMD1-53 inhibited the upregulation of ERS hallmarkers such as glucose-regulated protein 78 (GRP78), GRP94, activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1α, spliced-X-box-binding protein-1, protein kinase receptor-like ER kinase, and eukaryotic translation initiation factor 2α in mouse myocardium and rat CFs treated with Hcy. In addition, IMD1-53 decreased the production of inflammatory factors such as tumor necrosis factor-α, monocyte chemotactic protein-1, interleukin-6 (IL-6), and IL-1ß in the mouse myocardium and rat CFs treated with Hcy. Concurrently, IMD1-53 ameliorated the expression of nuclear factor-κB, transforming growth factor-ß1, and c-Jun N-terminal kinase in the mouse myocardium and rat CFs treated with Hcy. CONCLUSIONS: IMD potentially protects against myocardial fibrosis induced by Hcy in ApoE-/- mice, possibly via attenuating myocardial ERS and inflammation.

Inflammatory and fibrotic processes are involved in the cardiotoxic effect of sunitinib: Protective role of L-carnitine.

Sunitinib (Su) is currently approved for treatment of several malignances. However, along with the benefits of disease stabilization, cardiovascular toxicities have also been increasingly recognized. The aim of this study was to analyze which mechanisms are involved in the cardiotoxicity caused by Su, as well as to explore the potential cardioprotective effects of l-carnitine (LC). To this end, four groups of Wistar rats were used: (1) control; (2) rats treated with 400mg LC/kg/day; (3) rats treated with 25mg Su/kg/day; and (4) rats treated with LC+Su simultaneously. In addition, cultured rat cardiomyocytes were treated with an inhibitor of nuclear factor kappa B (NF-κB), in order to examine the role of this transcription factor in this process. An elevation in the myocardial expression of pro-inflammatory cytokines, together with an increase in the mRNA expression of NF-κB, was observed in Su-treated rats. These results were accompanied by an increase in the expression of pro-fibrotic factors, nitrotyrosine and NOX 2 subunit of NADPH oxidase; and by a decrease in that of collagen degradation factor. Higher blood pressure and heart rate levels were also found in Su-treated rats. All these alterations were inhibited by co-administration of LC. Furthermore, cardiotoxic effects of Su were blocked by NF-κB inhibition. Our results suggest that: (i) inflammatory and fibrotic processes are involved in the cardiac toxicity observed following treatment with Su; (ii) these processes might be mediated by the transcription factor NF-κB; (iii) LC exerts a protective effect against arterial hypertension, cardiac inflammation and fibrosis, which are all observed after Su treatment.

Atorvastatin Ameliorates Radiation-Induced Cardiac Fibrosis in Rats.

Radiation-induced heart injury is one of the major side effects of radiotherapy for thoracic malignancies. Previous studies have shown that radiotherapy induced myocardial fibrosis and intensified myocardial remodeling. In this study, we investigated whether atorvastatin could inhibit radiation-induced heart fibrosis in Sprague-Dawley rats, which were randomly divided into six groups: control; radiation only; and four treatment groups receiving atorvastatin plus radiation (E1, E2, E3 and E4). All rats, except the control group, received local heart irradiation in 7 daily fractions of 3 Gy for a total of 21 Gy. Rats in groups E1 (10 mg/kg/day) and E2 (20 mg/kg/day) received atorvastatin and radiation treatment until week 12 after exposure. Rats in groups E3 (10 mg/kg/day) and E4 (20 mg/kg/day) received atorvastatin treatment from 3 months before irradiation to week 12 after irradiation. The expressions of TGF-ß1, Smad2, Smad3, fibronectin, ROCK I and p-Akt in heart tissues were evaluated using real-time PCR or Western blot analyses. Atorvastatin significantly reduced the expression of TGF-ß1, Smad3/P-Smad3, ROCK I and p-Akt in rats of the E1-E4 groups and in a dose-dependent manner. Fibronectin exhibited a similar pattern of expression changes. In addition, echocardiography showed that atorvastatin treatment can inhibit the increase of left ventricular end-diastolic dimension, left ventricular end-systolic diameter and left ventricular posterior wall thickness, and prevent the decrease of ejection fraction and fraction shortening in E1-E4 groups compared with the radiation only group. This study demonstrated that radiation exposure increased the expression of fibronectin in cardiac fibroblasts and induced cardiac fibrosis through activation of the TGF-ß1/Smad3, RhoA/ROCK, and PI3K/AKT signaling pathways. Statins ameliorated radiation-induced cardiac fibrosis in Sprague-Dawley rats. Our results suggest that atorvastatin is effective for the treatment of radiation-induced cardiac fibrosis, especially with longer and higher dose atorvastatin treatment, as demonstrated in experimental group E4.

Effects of the Galanin Receptor Antagonist M40 on Cardiac Function and Remodeling in Rats with Heart Failure.

BACKGROUND: Sympathetic activation and parasympathetic withdrawal are important characteristics of heart failure. Recent studies demonstrate that galanin reduces the discharge of acetylcholine and inhibits vagal bradycardia by acting on galanin receptor type 1 (GalR1). We speculated that blocking GalR1 is beneficial for heart failure. METHODS: Rats with heart failure were induced by myocardial infarction. The rats were injected intraperitoneally with galanin receptor antagonist M40 solution (30 nmol/kg) or saline for 4 weeks. Cardiac function was assessed by echocardiography and brain natriuretic peptide (BNP) in plasma. The ratio of heart weight to body weight (HW/BW), hematoxylin-eosin (HE), and Masson trichrome stain was used to evaluate cardiac remodeling. Tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6) in plasma, and sarco(endo)plasmic reticulum Ca(2+) -ATPase (SERCA2) in heart tissue were detected to confirm the mechanism of the cardioprotection effect. RESULTS: Compared with rats injected with saline, M40 effectively improved cardiac function of contraction; decreased BNP, IL-6, and HW/BW (all P < 0.05); attenuated cardiac fibrosis; and upregulated SERCA2 (P < 0.05). CONCLUSION: M40 improves cardiac function and attenuates remodeling, suggesting that galanin receptor antagonist may be a potential therapeutic agent for HF.

AdipoR1/APPL1 potentiates the protective effects of globular adiponectin on angiotensin II-induced cardiac hypertrophy and fibrosis in neonatal rat atrial myocytes and fibroblasts.

Atrial hypertrophy and fibrosis are essential pathological features of atrial fibrillation. Recently, adiponectin has become a protein of interest due to its beneficial effects on cardiovascular diseases. However, the molecular mechanism of atrial structural remodeling and signaling pathways evoked by adiponectin remain unclear. In the present study, we investigated the cardioprotective effect of globular adiponectin (gAcrp) on angiotensin II-induced atrial hypertrophy and fibrosis in neonatal Sprague-Dawley rat. To further investigate the molecular mechanisms underlying the preventive effect of gAcrp, transfection of cells with siRNA was used to suppress the mRNA expression of adiponectin receptor 1 (AdipoR1) and its downstream adaptor protein APPL1. Non-silencing-Cy-3 labelled siRNA was used to determine transfection efficiency using fluorescence microscopy. The expression of atrial natriuretic peptide and procollagen type1 α-1, hypertrophy marker and fibrosis one, respectively, was detected by real-time PCR. Furthermore, the expression of adenosine monophosphate-activated protein kinase (AMPK), phosphatidylinositol 3-kinase (PI3K) and Akt was detected by western blotting. In addition, nuclear p65 translocation activity was analyzed by EMSA supershift assay. Our results showed that AdipoR1 and the adaptor protein APPL1 mediated the protective effects of gAcrp. In addition, the function of adiponectin and phosphorylation of AMPK were prominently diminished by inhibition of PI3K. Furthermore, nuclear factor-κB (NF-κB) transcription was diminished by the specific inhibition of AMPK. Taken together, AMPK pivotally interacts with NF-κB and PI3K, mediating the cardioprotective effect of adiponectin, and may serve as a therapeutic target for preventing atrial hypertrophy and fibrosis. Our present study suggests that gAcrp could ameliorate AngII-induced cardiac hypertrophy and fibrosis in rat atrial cells, which is mediated by the activation of AMPK signaling pathways. APPL1 and AdipoR1 are the key factors involved in the downstream of gAcrp approach.

Exercise training reduces cardiac dysfunction and remodeling in ovariectomized rats submitted to myocardial infarction.

The aim of this study was to evaluate whether exercise training (ET) prevents or minimizes cardiac dysfunction and pathological ventricular remodeling in ovariectomized rats subjected to myocardial infarction (MI) and to examine the possible mechanisms involved in this process. Ovariectomized Wistar rats were subjected to either MI or fictitious surgery (Sham) and randomly divided into the following groups: Control, OVX+SHAMSED, OVX+SHAMET, OVX+MISED and OVX+MIET. ET was performed on a motorized treadmill (5x/wk, 60 min/day, 8 weeks). Cardiac function was assessed by ventricular catheterization and Dihydroethidium fluorescence (DHE) was evaluated to analyze cardiac oxidative stress. Histological analyses were made to assess collagen deposition, myocyte hypertrophy and infarct size. Western Blotting was performed to analyze the protein expression of catalase and SOD-2, as well as Gp91phox and AT1 receptor (AT1R). MI-trained rats had significantly increased in +dP/dt and decreased left ventricular end-diastolic pressure compared with MI-sedentary rats. Moreover, oxidative stress and collagen deposition was reduced, as was myocyte hypertrophy. These effects occurred in parallel with a reduction in both AT1R and Gp91phox expression and an increase in catalase expression. SOD-2 expression was not altered. These results indicate that ET improves the functional cardiac parameters associated with attenuation of cardiac remodeling in ovariectomized rats subjected to MI. The mechanism seems to be related to a reduction in the expression of both the AT1 receptor and Gp91phox as well as an increase in the antioxidant enzyme catalase, which contributes to a reduction in oxidative stress. Therefore, ET may be an important therapeutic target for the prevention of heart failure in postmenopausal women affected by MI.

Localization of mesenchymal stem cells grafted with a hyaluronan-based scaffold in the infarcted heart.

BACKGROUND: Permanence of grafted stem cells in the infarcted myocardial area has been suggested to be favored by tissue engineering strategies, including the application of a scaffold as a cell support. However, an estimation of how many cells remain localized in the site of transplantation has never been done. The aim of this work was to investigate the localization of mesenchymal stem cells (MSCs) grafted with a well cell-adhesive polymer in the scar region of the infarcted heart. MATERIALS AND METHODS: Rat MSCs were engineered in a hyaluronan-based scaffold (HYAFF(®)11) for 3 wk. The hearts of donor rats were also explanted, subjected to coronary artery ligation, and grafted into the abdomen of syngeneic rats. Two wk after coronary ligation a small dish of the HYAFF(®)11/MSC construct was introduced into a pouch created in the ventricular wall of the infarct area and left for 2 wk. RESULTS: Under ex vivo conditions, MSCs tightly adhered to the hyaluronan fibers and secreted abundant extracellular matrix. In contrast, HYAFF(®)11 was not more surrounded by the engrafted MSCs 2 wk after construct transplantation. Most MSCs migrated near the border zone of the infarcted area close to the coronary vessels. Moreover, the infarcted region of the heart was enriched in capillaries and the degree of fibrosis was attenuated. CONCLUSIONS: Two wk after transplantation most MSCs grafted in the infarcted myocardium with HYAFF(®)11 had left the scaffold and moved to the border zone. Nevertheless, this treatment increased the myocardial vascularization and reduced the degree of fibrosis in the scar area.

Green tea polyphenols and 1-α-OH-vitamin D3 attenuate chronic inflammation-induced myocardial fibrosis in female rats.

Studies have suggested that 1-α-OH-vitamin D3 and green tea polyphenols (GTPs) are promising dietary supplements for mitigating chronic inflammation-induced fibrosis of vessels because of their anti-inflammatory properties. This study evaluated (1) the impact of 1-α-OH-vitamin D3 on myocardial fibrosis in female rats with chronic inflammation and (2) if 1-α-OH-vitamin D3 and GTPs have an additive or synergistic effect to attenuate myocardial fibrosis in these female rats. A 3-month study of a 2 (no 1-α-OH-vitamin D3 vs. 0.05 µg/kg 1-α-OH-vitamin D3, five times per week) ×2 (no GTPs vs. 0.5% GTPs in drinking water) factorial design in lipopolysaccharide (LPS)-administered female rats was performed. Additionally, a group receiving placebo administration was used to compare with a group receiving LPS administration only to evaluate the effect of LPS. Masson's Trichrome staining evaluated myocardial fibrosis in coronary vessels and surrounding myocardium. Spleen cyclooxygenase-2 mRNA expression was determined by real-time polymerase chain reaction. Total lipid profiles were also determined. Whole blood was used for differential cell counts. Data were analyzed by two-way analysis of variance followed by mean separation procedures. At 3 months LPS administration induced myocardial fibrosis in vessels and surrounding myocardium, spleen cyclooxygenase-2 mRNA expression, and elevated leukocyte counts, whereas both 1-α-OH-vitamin D3 administration and GTPs supplementation significantly attenuated these pro-inflammatory events. The inhibitory effects of 1-α-OH-vitamin D3 and GTPs seem to be an individual effect, instead of an additive or synergistic effect. 1-α-OH-vitamin D3 and GTPs lowered red blood cell counts, hematocrit, and hemoglobin. Neither 1-α-OH-vitamin D3 nor GTPs affected lipid profiles. In summary, both 1-α-OH-vitamin D3 administration and GTPs supplementation mitigate myocardial fibrosis through suppression of a chronic inflammation innate immune response.

Enhanced cardiac inflammation and fibrosis in ovariectomized hypertensive rats: a possible mechanism of diastolic dysfunction in postmenopausal women.

Diastolic dysfunction is more prevalent in individuals with hypertension, particularly postmenopausal women; however, the pathogenesis of diastolic dysfunction remains unknown. Pressure overload activates cardiac inflammation, which induces myocardial fibrosis and diastolic dysfunction in rats with a suprarenal aortic constriction (AC). Therefore, we examined the effects of bilateral ovariectomy (OVX) on left ventricle (LV) remodeling, diastolic dysfunction and cardiac inflammation in hypertensive female rats. Rats were randomized to OVX+AC, OVX and AC groups as well as a Control group receiving sham operations for both the procedures. Rats underwent OVX at 6 weeks and AC at 10 weeks (Day 0). At Day 28, OVX did not appear to affect arterial pressure, cardiac hypertrophy or LV fractional shortening in AC rats. However, OVX increased myocardial fibrosis, elevated LV end-diastolic pressure and reduced the transmitral Doppler spectra early to late filling velocity ratio in AC rats. AC-induced transient myocardial monocyte chemoattractant protein-1 expression and macrophage infiltration, both of which peaked at Day 3 and were augmented and prolonged by OVX. At Day 28, dihydroethidium staining revealed superoxide generation in the intramyocardial arterioles in the OVX+AC group but not in the AC group. NOX1, a functional subunit of nicotinamide adenine dinucleotide phosphate oxidase, was upregulated only in the OVX+AC group at Day 28. Chronic 17ß-estradiol replacement prevented the increases in macrophage infiltration, NOX1 upregulation, myocardial fibrosis and diastolic dysfunction in OVX+AC rats. In conclusion, we suggest that estrogen deficiency augments cardiac inflammation and oxidative stress and thereby aggravates myocardial fibrosis and diastolic dysfunction in hypertensive female rats. The findings provide insight into the mechanism underlying diastolic dysfunction in hypertensive postmenopausal women.

Tumor suppressor A20 protects against cardiac hypertrophy and fibrosis by blocking transforming growth factor-beta-activated kinase 1-dependent signaling.

A20 or tumor necrosis factor-induced protein 3 is a negative regulator of nuclear factor kappaB signaling. A20 has been shown previously to attenuate cardiac hypertrophy in vitro and postmyocardial infarction remodeling in vivo. In the present study, we tested the hypothesis that overexpression of A20 in the murine heart would protect against cardiac hypertrophy in vivo. The effects of constitutive human A20 expression on cardiac hypertrophy were investigated using in vitro and in vivo models. Cardiac hypertrophy was produced by aortic banding in A20 transgenic mice and control animals. The extent of cardiac hypertrophy was quantitated by echocardiography, as well as by pathological and molecular analyses of heart samples. Constitutive overexpression of human A20 in the murine heart attenuated the hypertrophic response and markedly reduced inflammation, apoptosis, and fibrosis. Cardiac function was also preserved in hearts with increased A20 levels in response to hypertrophic stimuli. Western blot experiments further showed A20 expression markedly blocked transforming growth factor-beta-activated kinase 1-dependent c-Jun N-terminal kinase/p38 signaling cascade but with no difference in either extracellular signal-regulated kinase 1/2 or AKT activation in vivo and in vitro. In cultured neonatal rat cardiac myocytes, [3H]proline incorporation and Western blot assays revealed that A20 expression suppressed transforming growth factor-beta-induced collagen synthesis and transforming growth factor-beta-activated kinase 1-dependent Smad 2/3/4 activation. In conclusion, A20 improves cardiac functions and inhibits cardiac hypertrophy, inflammation, apoptosis, and fibrosis by blocking transforming growth factor-beta-activated kinase 1-dependent signaling.