Benefits of SGLT2 Inhibitor: Preventing Heart Failure and Beyond

No abstract available.

Functional Relevance of Macrophage-mediated Inflammation to Cardiac Regeneration / 전남의대학술지

Cardiovascular disease remains the leading cause of death worldwide and regenerative medicine is a promising therapeutic option for this disease. We have developed various techniques to attenuate the cardiac remodeling and to regenerate cardiovascular systems via stem cell application. Besides cell therapy, we are interested in the modulation of pathological inflammation mediated by macrophages in the damaged heart tissue to arouse endogenous reparative responses with biocompatible small molecules. Certainly, current understanding of mechanisms of tissue regeneration will lead to the development of innovative regenerative medicine for cardiovascular disease.

Intramyocardial Injection of Stem Cells in Pig Myocardial Infarction Model: The First Trial in Korea

Although cell therapy is emerged for cardiac repair, its efficacy is modest by intracoronary infusion. Therefore, we established the intramyocardial delivery technique using a left ventricular (LV) mapping system (NOGA® XP) using 18 pigs. After adipose tissue-derived mesenchymal stem cells (ATSCs) were delivered intramyocardially to porcine infarcted heart, LV ejection fraction (EF) was increased, and LV chamber size was decreased. We proved the therapeutic effect of intramyocardial injection of ATSC through a LV mapping system in the porcine model for the first time in Korea. The adoption of this technique may accelerate the translation into a clinical application in the near future.

Mesenchymal stem cells reciprocally regulate the M1/M2 balance in mouse bone marrow-derived macrophages

Mesenchymal stem cells (MSCs) have been widely studied for their applications in stem cell-based regeneration. During myocardial infarction (MI), infiltrated macrophages have pivotal roles in inflammation, angiogenesis and cardiac remodeling. We hypothesized that MSCs may modulate the immunologic environment to accelerate regeneration. This study was designed to assess the functional relationship between the macrophage phenotype and MSCs. MSCs isolated from bone marrow and bone marrow-derived macrophages (BMDMs) underwent differentiation induced by macrophage colony-stimulating factor. To determine the macrophage phenotype, classical M1 markers and alternative M2 markers were analyzed with or without co-culturing with MSCs in a transwell system. For animal studies, MI was induced by the ligation of the rat coronary artery. MSCs were injected within the infarct myocardium, and we analyzed the phenotype of the infiltrated macrophages by immunostaining. In the MSC-injected myocardium, the macrophages adjacent to the MSCs showed strong expression of arginase-1 (Arg1), an M2 marker. In BMDMs co-cultured with MSCs, the M1 markers such as interleukin-6 (IL-6), IL-1beta, monocyte chemoattractant protein-1 and inducible nitric oxide synthase (iNOS) were significantly reduced. In contrast, the M2 markers such as IL-10, IL-4, CD206 and Arg1 were markedly increased by co-culturing with MSCs. Specifically, the ratio of iNOS to Arg1 in BMDMs was notably downregulated by co-culturing with MSCs. These results suggest that the preferential shift of the macrophage phenotype from M1 to M2 may be related to the immune-modulating characteristics of MSCs that contribute to cardiac repair.

Angiopoietin-Like 4 Is Involved in the Poor Angiogenic Potential of High Glucose-Insulted Bone Marrow Stem Cells

BACKGROUND AND OBJECTIVES: Diabetes is reported to reduce the function or number of progenitor cells. We compared the gene expression patterns of bone marrow-derived mesenchymal stem cells from diabetic (DM-BMCs) and healthy (non-DM-BMCs) rats and suggested Angiopoietin-like 4 (Angptl4) could be a responsible factor for impaired angiogenesis of DM-BMCs. SUBJECTS AND METHODS: BMCs were isolated from DM or non-DM rat, and in vitro angiogenesis activity was compared by tube formation assay on Matrigel and complementary deoxyribonucleic acid expression was analyzed by microarray with or without oxytocin treatment. Human BMCs (hBMCs) were treated with high glucose, and were performed polymerase chain reaction, Western blot, and enzyme-linked immunosorbent assay. Angptl4 plasmid DNA and micro ribonucleic acid-132 (miR-132) were transfected to immortalized hBMCs. RESULTS: In vitro angiogenesis assay showed the impaired tube formation in DM-BMCs, and slightly recovery by oxytocin treatment. Angptl4, an adipokine, was upregulated in DM-BMCs compared to non-DM-BMCs. Oxytocin treatment reduced Angptl4 in DM-BMCs. In hBMCs, overexpression of Angptl4 attenuated the tube formation. In addition to Angptl4, miR-132 was increased by high glucose treatment. Collectively, high glucose resulted in impaired tube formation through miR-132 induction and Angptl4 upregulation in BMCs. CONCLUSION: Our results show that the angiogenic activity of BMCs is impaired by high glucose stress, which would be mediated by Angptl4 and miR-132.

A Long Road for Stem Cells to Cure Sick Hearts: Update on Recent Clinical Trials

The contribution of stem cells to cure damaged hearts has finally been unraveled. A large number of preclinical and clinical studies have showed beneficial outcomes after myocardial infarction. In this review, the current understanding of stem cell therapy in preclinical and clinical experiences is summarized. Stem cells from bone marrow have shown a potential to improve cardiac performance after myocardial infarction in animal and early clinical studies. Clinical trials from all over the world have provided safety assessments of stem cell therapy with marginal improvement of clinical outcomes. Thus, further investigations should be encouraged to resolve the discrepancies between studies, clinical issues, and unclear translational findings. This review provides information and commentary on key trials for stem cell-based treat-ment of cardiovascular disease.

The Protective Effect of Curcumin on Myocardial Ischemia-Reperfusion Injury

BACKGROUND AND OBJECTIVES: Myocardial ischemia-reperfusion (I/R) injury is one of the major causes of cardiac mortality. Curcumin, an active component extracted from turmeric in curry, inhibits inflammatory responses. This study was designed to investigate whether curcumin can exert beneficial effects on myocardial I/R injury. MATERIALS AND METHODS: Sprague-Dawley male rats received a normal diet or a curcumin diet (80 mg/kg/d) for one week, and I/R injury was induced by ligating the left anterior descending artery (LAD) for 30 min followed by release. After 24 hours, the myocardium was extracted to evaluate the myeloperoxidase (MPO) activity and the vascular cellular adhesion molecule (VCAM)-1 protein level. The apoptotic cardiomyocytes and neutrophils were counted and quantified by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining at 14 days after I/R. RESULTS: In the infarcted myocardium of the curcumin-fed rats, the MPO activity (32.9+/-2.2% of the control, p=0.001) and the VCAM-1 protein (28.7+/-2.9% of control, p=0.001) level were significantly attenuated. The number of neutrophils was lower in the curcumin-fed rats (57+/-12% of the control, p=0.024). A reduction of the apoptotic cardiomyocytes was also observed in the curcumin-fed I/R rats (36+/-9.2% of the control, p=0.032). CONCLUSION: The cardioprotective effects of curcumin on an I/R injury rat model could include anti-inflammation activities and inhibition of apoptosis that occurred in the cardiomyocytes. Our findings suggest that curcumin has a positive contribution as a dietary supplement for the prevention of heart disease.

Therapeutic Potential of Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Ischemic Myocardium

BACKGROUND AND OBJECTIVES: We designed this study to determine the therapeutic potentials of umbilical cord blood (UCB)-mesenchymal stem cells (MSCs), as compared with bone marrow (BM)-MSCs. MATERIALS AND METHODS: MSCs were isolated from UCB and BM. For the in vivo study, myocardial infarction was induced by ligation of the left anterior descending coronary artery (LAD) in rats for 30 min, and this was followed by release; the MSCs were then injected into a designated point around the infarcted area. Echocardiographs were performed two weeks after surgery. For the in vitro study, a cDNA microarray and cytokine array were performed to compare the MSCs from UCB and from BM. Cell migration was assessed by a wound scratch assay, and the level of cardiac ankyrin repeat protein (CARP) was determined by reverse transcriptase-polymer chain reaction (RT-PCR) or Western blot analysis. RESULTS: For the echocardiograph findings, the fractional shortening (FS) was 43.9% in the UCB-MSCs group and it was 38.6% in the BM-MSC group. The ejection fraction (EF) was 79.8% in the UCB-MSC group and it was 72.4% in the BM-MSC group (control FS: 26.2% and the control EF: 56.6%). CARP was one of the highly expressed genes in the UCB-MSCs on the cDNA microarray. The mRNA and the expressed level of CARP protein in the UCB-MSCs were higher than those in the BM-MSCs. The cell migration of the CARP small interfering ribonucleic acid (siRNA) transfected UCB-MSCs was delayed compared to that of the normal UCB-MSCs (p<0.05) CONCLUSION: Our study directly compared the two types of MSCs from UCB and BM, and we suggest that the CARP molecule might be responsible for the motility of UCB-MSCs.

Curcumin Attenuates Nuclear Factor-kappaB, c-Jun N-Terminal Kinase and p38 in Tumor Necrosis Factor-alpha-Stimulated Endothelial Cells

BACKGROUND AND OBJECTIVES: Curcumin, a yellow pigment of turmeric in curry, has been reported to interfere with nuclear factor (NF)-kappaB. This study was designed to investigate the underlying pathway of the anti-inflammation effect of curcumin on endothelial cells. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVECs) were stimulated with tumor necrosis factor (TNF)-alpha (10 ng/mL). The levels of intracellular reactive oxygen species (ROS) were examined using a fluorescent dye DCFH-DA, and the adhesion of U-937 monocytes to the HUVECs was then examined. Nuclear factor kappa B (NF-kappaB) activation was determined by the NF-kappaB p65 translocation to the nucleus via immunocytochemistry. The expression of the NF-kappaB dependent pro-inflammatory molecules were measured by RT-PCR and ELISA. The phosphorylations of c-Jun N-terminal protein kinase (JNK), p38 and STAT-3 (signal transducer and activator of transcription-3) were measured by Western blotting. RESULTS: Curcumin blocked the activation of NF-kappaB by TNF-alpha, and it also reduced the ROS, monocyte adhesion and the phosphorylation of JNK, p38 and STAT-3 in the TNF-alpha-stimulated HUVECs. The expression of intracellular cell adhesion molecule (ICAM)-1, monocyte chemoattractant protein (MCP)-1, and interleukin (IL)-8 were attenuated by curcumin at both the transcription and translation levels. CONCLUSION: We suggest that curcumin could contribute to protection against the adverse vascular effects of the pro-inflammatory response through the modulation of NF-kappaB, JNK, p38 and STAT-3, and this is in addition to its antioxidant effect in endothelial cells.

The Role of Nuclear Factor Kappa B Activation in Atherosclerosis and Ischemic Cardiac Injury

The NF-kappaB family of transcription factors plays a critical role in many tissues by modulating both inflammation and cell survival, and this primarily comes about through transcriptional regulation of the downstream effecter genes. This central role of coordinating complex programs of gene induction suggests that the NF-kappaB transcription factors and/or the signaling pathways leading to their activation may present a prime opportunity for performing therapeutic intervention. However, the dual role of this pathway in inflammation and survival dictates rigorous and empiric validation of such interventions in realistic models of disease before we can translate research findings to the clinical arena. Interestingly, the precise approach chosen to modulate NF-kappaB activation appears to dramatically alter the balance of the downstream effects on apoptosis and inflammation. Here we provide a brief overview of NF-kappaB signaling and its role in atherogenesis as well as in acute coronary syndromes, while considering the clinical implications for therapeutic strategies.

The Effects of Mesenchymal Stem Cells Transduced with Akt in a Porcine Myocardial Infarction Model

BACKGROUND AND OBJECTIVES: This study was designed to examine whether mesenchymal stem cells (MSCs) transduced with Akt are more resistant to apoptosis, and enhance cardiac repair, following the transplantation into infarcted porcine myocardium. MATERIALS AND METHODS: The MSCs were separated and genetically engineered using ex-vivo myr-Akt-adenoviral gene transfer. The MSCs were delivered by intracoronary injection into infarcted porcine myocardium [group I (control: n=8), media only; group II (n=8), MSCs only; group III (n=8), MSCs modified with Akt]. Myocardial SPECT was performed before and 4 weeks after the MSC transplantation, with the pigs sacrificed for immunocytochemical staining and histological analyses for apoptosis and fibrosis. RESULTS: The left ventricular ejection fractions (LVEF) were 44.7+/-16.6, 35.9+/-10.0 and 41.1+/-7.9% at first (each n=8), which changed to 29.7+/-8.5, 39.0+/-9.5 and 60.4+/-16.6% at 4 weeks after the MSC implantation in groups I, II and III, respectively. The myocardial infarction (MI) area changed from 17.6+/-9.2, 35.0+/-11.8 and 24.3+/-11.2% to 19.6+/-10.1, 27.2+/-13.9 and 7.4+/-5.3% in groups I, II and III, respectively. Transplantation of 1X10(7) cells into group II increased the deltaLVEF (-15.0+/-15.3 vs. 3.0+/-4.3%, n=8 in each, p=0.016) and decreased the deltaMI area (2.1+/-0.9 vs. 5.6+/-3.1%, n=8 in each, p=0.04) compared to those of the control group, and these changes were more significant in the deltaLVEF (19.3+/-15.7%, p=0.006) and deltaMI area (-16.4+/-6.1%, p=0.037) of group III. CONCLUSION: MSCs transduced with Akt enhance the repair of the injured area, prevent remodeling and restore systolic performance in infarcted porcine myocardium.

Carvedilol Inhibits Expressions of Vascular Cell Adhesion Molecule-1, Intercellular Adhesion Molecule-1, Monocyte Chemoattractant-1, and Interleukin-8 via NF-kappaB Inhibition in Human Endothelial Cells

BACKGROUND AND OBJECTIVES: Carvedilol is an anti-oxidative, the cardioprotective effects of which are mediated by the inhibition of NF-kappaB activation. The present study was designed to examine the effects of carvedilol, an alpha1- and beta-blocker, on tumor necrosis factor (TNF)-alpha stimulated human umbilical vein endothelial cells (HUVEC). Materials and METHODS: HUVEC were treated with TNF-alpha (10 ng/mL) in either the absence or presence of carvedilol. The levels of intracellular reactive oxygen species (ROS) were examined using a fluorescent dye DCFH-DA, with the adhesion of U-937 monocyte to the HUVEC. Nuclear factor kappa B (NF-kappaB) activation was determined by NF-kappaB p65 translocation to the nucleus using Western blotting and immunocytochemistry. The expressions of NF-kappaB dependent pro-inflammatory molecules, i.e., vascular cell adhesion molecule (VCAM)-1, intercellular adhesion molecule (ICAM)-1, monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-8, were measured by RT-PCR and ELISA. Bcl-2 and phosphorylation of c-Jun N-terminal protein kinase (JNK) were measured using Western blotting. RESULTS: TNF-alpha treatment increased the activation of NF-kappaB, suppressed Bcl-2, and increased the phosphorylation of JNK, the ROS level and the adhesion of U-937. The levels of mRNA and protein expressions of VCAM-1, ICAM-1, MCP-1 and IL-8 were up-regulated by TNF-alpha. Carvedilol inhibited the phosphorylation of JNK, ROS formation and the adhesion of U-937 monocyte. In addition, carvedilol reduced the production of VCAM-1, ICAM-1, MCP-1 and IL-8 at the mRNA and protein levels, via the suppression of NF-kappaB activation. CONCLUSION: These results suggested that the anti-inflammatory effects of carvedilol on TNF-alpha stimulated endothelial cells could be explained by its ROS-scavenging and NF-kappaB inactivation properties.

in vivo Cardiac Gene Transfer of Dominant Negative IKK-beta Reduces Myocardial Inflammation, Apoptosis, and Infarction after Ischemia-Reperfusion Injury

BACKGROUND AND OBJECTIVES: NF-kappaB transcription factors drive the expressions of many genes involved in inflammation and cell survival, which are both important in ischemia-reperfusion (IR) injury. IKK-beta can mediate NF-kappaB activation through the phosphorylation of IkappaB; however, alternative pathways of activation exist. MATERIALS AND METHODS: To test the role of IKK-beta in cardiac IR injury, cardiac gene transfer of dominant negative IKK-beta (dnIKK-beta) was performed in rats 48 hr prior to IR. RESULTS: Adenoviral gene transfer was found to result in regional transgene expression encompassing ~60% of the ischemic area. Ad.dnIKK-beta reduced the IR-induced NF-kappaB translocation and IkappaB-alpha degradation, and blocked induction of the NF-kappaB-dependent inflammatory chemokine, MCP-1, in the ischemic area compared to the Ad.EGFP.beta-gal treated rats (p<0.05). Neutrophil infiltration in the ischemic area (as indicated by myeloperoxidase activity) was decreased by 33% in the Ad.dnIKK-beta treated rats compared to the Ad.EGFP.beta-gal treated rats (p<0.05). Ad.dnIKK-beta also reduced IR-induced apoptosis, as reflected by the attenuated DNA laddering compared to rats injected with either buffer or Ad.EGFP.beta-gal. The ischemic area was not affected by dnIKK-beta expression. However, Ad.dnIKK-beta reduced infarction(%MI) by 57% compared to the Ad.EGFP.beta-gal treated rats (p<0.01). CONCLUSION: Thus, in vivo gene transfer of dnIKK-beta prevents the IR-induced activation of NF-kappaB. In this setting, abrogation of pro-inflammatory signals appears more important than loss of NF-kappaB dependent survival factors, resulting in an overall reduction in apoptosis and infarct size. These data suggest that IKK-beta may represent a valuable target for therapeutic intervention in IR injury.

Involvement of ROS and JNK1 in selenite-induced a poptosisin Chang liver cells

Selenium is a dietary essential trace nutrient with important biological roles. Selenocompounds were reported to induce apoptosis in many types of tumor cells. In this study, we investigated the signaling pathway involved in the selenite-induced apoptosis using Chang liver cells as a non-malignant cell model. The Chang liver cell apoptosis induced by selenite (10 mM) was confirmed by DNA fragmentation and typical apoptotic nuclear changes. Treatment of selenite increased intracellular reactive oxygen species (ROS) level and c-Jun N-terminal kinase1 (JNK1) phosphorylation. The selenite-induced cell death was attenuated by SP600125, a specific inhibitor of JNK, and by dominant negative JNK1 (DN-JNK1). Antioxidants such as glutathione (GSH), N-acetyl cysteine (NAC), curcumin, epigallocatechin gallate (EGCG) and epicatechin (EC) inhibited selenite-induced intracellular ROS elevation and JNK1 phosphorylation. Our results suggest that selenite-induced apoptosis in Chang liver cells was preceded by the ROS generation and JNK1 activation.

Activation of Mitogen-activated Protein Kinases in Hypoxia-induced Apoptosis of PC12 Cell

BACKGROUND: The Mitogen-activated Protein Kinase (MAPK) family is comprised of key regulatory proteins that control the cellular response to both proliferation and stress signals. Cell death is usually mediated through apoptosis regulated by extracellular factors. We investigated the apoptotic processes of PC12 cells induced by hypoxia and the activation of MAPKs in apoptosis. METHODS: PC12 cells were maintained in a RPMI 1640 medium containing 5% fetal bovine serum (FBS), 10% horse serum, and antibiotics. Hypoxia was induced in a humidified 37 degrees C incubator within a BBL GasPac Pouch. The apoptosis of PC12 cells was observed with an electron microscope and DNA laddering on agarose-gel electrophoresis. The phosphorylation of MAPKs was measured by an image analysis system after a Western blot. RESULTS: Hypoxic apoptosis occurred maximally when PC12 cells in 2% FBS and 5mM glucose media were incubated in an anaerobic state for 6 hours and then reoxygenated for 18 hours. The phosphorylation of MAPKs was observed 30 min after hypoxia and sustained for at least 2 hours. Phosphorylations of extracellular signal-regulated kinase (ERK) and p38 kinase were reduced after 4 hours of hypoxia, whereas those of c-Jun N-terminal kinase (JNK) persisted for 6 hrs Nerve Growth Factor (NGF). Significantly inhibited DNA fragmentation in hypoxia-induced apopto-sis of PC12 cells. NGF accentuated phosphorylation of ERK in both normoxia and hypoxia. Nerve growth factor (NGF) reduced the phosphorylation of JNK but did not affect the phosphorylation of p38 kinase. CONCLUSIONS: We established the conditions for PC12 cell apoptosis caused by hypoxia. These results suggest that activation of JNK and p38 kinase might be the apoptotic signals induced by hypoxia and regulated by different pathways. (J Korean Neurol Assoc 19(4):384~392, 2001)