Summary Background c-kit-positive, lineage-negative cardiac stem cells (CSCs) improve post-infarction left ventricular (LV) dysfunction when administered to animals. We undertook a phase 1 trial ...(Stem Cell Infusion in Patients with Ischemic cardiOmyopathy SCIPIO) of autologous CSCs for the treatment of heart failure resulting from ischaemic heart disease. Methods In stage A of the SCIPIO trial, patients with post-infarction LV dysfunction (ejection fraction EF ≤40%) before coronary artery bypass grafting were consecutively enrolled in the treatment and control groups. In stage B, patients were randomly assigned to the treatment or control group in a 2:3 ratio by use of a computer-generated block randomisation scheme. 1 million autologous CSCs were administered by intracoronary infusion at a mean of 113 days (SE 4) after surgery; controls were not given any treatment. Although the study was open label, the echocardiographic analyses were masked to group assignment. The primary endpoint was short-term safety of CSCs and the secondary endpoint was efficacy. A per-protocol analysis was used. This study is registered with ClinicalTrials.gov , number NCT00474461. Findings This study is still in progress. 16 patients were assigned to the treatment group and seven to the control group; no CSC-related adverse effects were reported. In 14 CSC-treated patients who were analysed, LVEF increased from 30·3% (SE 1·9) before CSC infusion to 38·5% (2·8) at 4 months after infusion (p=0·001). By contrast, in seven control patients, during the corresponding time interval, LVEF did not change (30·1% 2·4 at 4 months after CABG vs 30·2% 2·5 at 8 months after CABG). Importantly, the salubrious effects of CSCs were even more pronounced at 1 year in eight patients (eg, LVEF increased by 12·3 ejection fraction units 2·1 vs baseline, p=0·0007). In the seven treated patients in whom cardiac MRI could be done, infarct size decreased from 32·6 g (6·3) by 7·8 g (1·7; 24%) at 4 months (p=0·004) and 9·8 g (3·5; 30%) at 1 year (p=0·04). Interpretation These initial results in patients are very encouraging. They suggest that intracoronary infusion of autologous CSCs is effective in improving LV systolic function and reducing infarct size in patients with heart failure after myocardial infarction, and warrant further, larger, phase 2 studies. Funding University of Louisville Research Foundation and National Institutes of Health.
RATIONALE:Endothelial progenitor cells (EPCs) respond to SDF-1 through receptors CXCR7 and CXCR4. Whether SDF-1 receptors involves in diabetes induced EPCs dysfunction remains unknown.
OBJECTIVE:To ...determine the role of SDF-1 receptors in diabetic EPCs dysfunction.
METHODS AND RESULTS:CXCR7 expression, but not CXCR4 was reduced in EPCs from db/db mice, which coincided with impaired tube formation. Knockdown of CXCR7 impaired tube formation of EPCs from normal mice, while up-regulation of CXCR7 rescued angiogenic function of EPCs from db/db mice. In normal EPCs treated with oxidized low-density lipoprotein (ox-LDL) or high glucose (HG) also reduced CXCR7 expression, impaired tube formation and increased oxidative stress and apoptosis. The damaging effects of ox-LDL or HG were markedly reduced by SDF-1 pretreatment in EPCs transduced with CXCR7 lentivirus (CXCR7-EPCs) but not in EPCs transduced with control lentivirus (Null-EPCs). Most importantly, CXCR7-EPCs were superior to Null-EPCs for therapy of ischemic limbs in db/db mice. Mechanistic studies demonstrated that ox-LDL or HG inhibited Akt and GSK-3β phosphorylation, nuclear export of Fyn and nuclear localization of Nrf2, blunting Nrf2 downstream target genes HO-1, NQO-1 and catalase, and inducing an increase in EPC oxidative stress. This destructive cascade was blocked by SDF-1 treatment in CXCR7-EPCs. Furthermore, inhibition of PI3K/Akt prevented SDF-1/CXCR7-mediated Nrf2 activation and blocked angiogenic repair. Moreover, Nrf2 knockdown almost completely abolished the protective effects of SDF-1/CXCR7 on EPC function in vitro and in vivo.
CONCLUSIONS:Elevated expression of CXCR7 enhances EPC resistance to diabetes-induced oxidative damage and improves therapeutic efficacy of EPCs in treating diabetic limb ischemia. The benefits of CXCR7 are mediated predominantly by an Akt/GSK-3β/Fyn pathway via increased activity of Nrf2.
Heme oxygenase-1 (HO-1) is an inducible stress-response protein that imparts antioxidant and antiapoptotic effects. However, its pathophysiological role in cardiac remodeling and chronic heart ...failure (HF) is unknown. We hypothesized that induction of HO-1 in HF alleviates pathological remodeling.
Adult male nontransgenic and myocyte-restricted HO-1 transgenic mice underwent either sham operation or coronary ligation to induce HF. Four weeks after ligation, nontransgenic HF mice exhibited postinfarction left ventricular (LV) remodeling and dysfunction, hypertrophy, fibrosis, oxidative stress, apoptosis, and reduced capillary density, associated with a 2-fold increase in HO-1 expression in noninfarcted myocardium. Compared with nontransgenic mice, HO-1 transgenic HF mice exhibited significantly (P<0.05) improved postinfarction survival (94% versus 57%) and less LV dilatation (end-diastolic volume, 46+/-8 versus 85+/-32 microL), mechanical dysfunction (ejection fraction, 65+/-9% versus 49+/-16%), hypertrophy (LV/tibia length 4.4+/-0.4 versus 5.2+/-0.6 mg/mm), interstitial fibrosis (11.2+/-3.1% versus 18.5+/-3.5%), and oxidative stress (3-fold reduction in tissue malondialdehyde). Moreover, myocyte-specific HO-1 overexpression in HF promoted tissue neovascularization and ameliorated myocardial p53 expression (2-fold reduction) and apoptosis. In isolated mitochondria, mitochondrial permeability transition was inhibited by HO-1 in a carbon monoxide (CO)-dependent manner and was recapitulated by the CO donor tricarbonylchloro(glycinato)ruthenium(II) (CORM-3). HO-1-derived CO also prevented H2O2-induced cardiomyocyte apoptosis and cell death. Finally, in vivo treatment with CORM-3 alleviated postinfarction LV remodeling, p53 expression, and apoptosis.
HO-1 induction in the failing heart is an important cardioprotective adaptation that opposes pathological LV remodeling, and this effect is mediated, at least in part, by CO-dependent inhibition of mitochondrial permeability transition and apoptosis. Augmentation of HO-1 or its product, CO, may represent a novel therapeutic strategy for ameliorating HF.
Heart failure after myocardial infarction (MI) continues to be the most prevalent cause of morbidity and mortality worldwide. Although pharmaceutical agents and interventional strategies have ...contributed greatly to therapy, new and superior treatment modalities are urgently needed given the overall disease burden. Stem cell-based therapy is potentially a promising strategy to lead to cardiac repair after MI. An array of cell types has been explored in this respect, including skeletal myoblasts, bone marrow (BM)-derived stem cells, embryonic stem cells, and more recently, cardiac progenitor cells (CPCs). Recently studies have obtained evidence that transplantation of CPCs or BM-derived very small embryonic-like stem cells can improve cardiac function and alleviate cardiac remodeling, supporting the potential therapeutic utility of these cells for cardiac repair. This report summarizes the current data from those studies and discusses the potential implication of these cells in developing clinically-relevant stem cell-based therapeutic strategies for cardiac regeneration. (Circ J 2010; 74: 390 - 404)
RATIONALE:Myocardial ischemia–reperfusion (I/R) results in the generation of oxygen-derived free radicals and the accumulation of lipid peroxidation–derived unsaturated aldehydes. However, the ...contribution of aldehydes to myocardial I/R injury has not been assessed.
OBJECTIVE:We tested the hypothesis that removal of aldehydes by glutathione S-transferase P (GSTP) diminishes I/R injury.
METHODS AND RESULTS:In adult male C57BL/6 mouse hearts, Gstp1/2 was the most abundant GST transcript followed by Gsta4 and Gstm4.1, and GSTP activity was a significant fraction of the total GST activity. mGstp1/2 deletion reduced total GST activity, but no compensatory increase in GSTA and GSTM or major antioxidant enzymes was observed. Genetic deficiency of GSTP did not alter cardiac function, but in comparison with hearts from wild-type mice, the hearts isolated from GSTP-null mice were more sensitive to I/R injury. Disruption of the GSTP gene also increased infarct size after coronary occlusion in situ. Ischemia significantly increased acrolein in hearts, and GSTP deficiency induced significant deficits in the metabolism of the unsaturated aldehyde, acrolein, but not in the metabolism of 4-hydroxy-trans-2-nonenal or trans-2-hexanal; on ischemia, the GSTP-null hearts accumulated more acrolein-modified proteins than wild-type hearts. GSTP deficiency did not affect I/R-induced free radical generation, c-Jun N-terminal kinase activation, or depletion of reduced glutathione. Acrolein exposure induced a hyperpolarizing shift in INa, and acrolein-induced cell death was delayed by SN-6, a Na/Ca exchange inhibitor. Cardiomyocytes isolated from GSTP-null hearts were more sensitive than wild-type myocytes to acrolein-induced protein crosslinking and cell death.
CONCLUSIONS:GSTP protects the heart from I/R injury by facilitating the detoxification of cytotoxic aldehydes, such as acrolein.
In the failing heart, iNOS is expressed by both macrophages and cardiomyocytes. We hypothesized that inflammatory cell-localized iNOS exacerbates left ventricular (LV) remodeling. Wild-type (WT) ...C57BL/6 mice underwent total body irradiation and reconstitution with bone marrow from iNOS
−/−
mice (iNOS
−/−
c) or WT mice (WTc). Chimeric mice underwent coronary ligation to induce large infarction and ischemic heart failure (HF), or sham surgery. After 28 days, as compared with WTc sham mice, WTc HF mice exhibited significant (
p
< 0.05) mortality, LV dysfunction, hypertrophy, fibrosis, oxidative/nitrative stress, inflammatory activation, and iNOS upregulation. These mice also exhibited a ~twofold increase in circulating Ly6C
hi
pro-inflammatory monocytes, and ~sevenfold higher cardiac M1 macrophages, which were primarily CCR2
–
cells. In contrast, as compared with WTc HF mice, iNOS
−/−
c HF mice exhibited significantly improved survival, LV function, hypertrophy, fibrosis, oxidative/nitrative stress, and inflammatory activation, without differences in overall cardiac iNOS expression. Moreover, iNOS
−/−
c HF mice exhibited lower circulating Ly6C
hi
monocytes, and augmented cardiac M2 macrophages, but with greater infiltrating monocyte-derived CCR2
+
macrophages vs. WTc HF mice. Lastly, upon cell-to-cell contact with naïve cardiomyocytes, peritoneal macrophages from WT HF mice depressed contraction, and augmented cardiomyocyte oxygen free radicals and peroxynitrite. These effects were not observed upon contact with macrophages from iNOS
−/−
HF mice. We conclude that leukocyte iNOS is obligatory for local and systemic inflammatory activation and cardiac remodeling in ischemic HF. Activated macrophages in HF may directly induce cardiomyocyte contractile dysfunction and oxidant stress upon cell-to-cell contact; this juxtacrine response requires macrophage-localized iNOS.
The role of cyclooxygenase-2 (COX-2) in cardiovascular biology remains controversial. Although COX-2 has been reported to mediate the protective actions of late preconditioning, other studies show ...that it is also an important mediator of inflammation, toxic shock, and apoptosis, resulting in significant dysfunction and injury in several tissues. To determine whether increased myocardial COX-2, in itself, is protective, cardiac-specific, inducible (Tet-off) COX-2 transgenic (iCOX-2 TG) mice were generated by crossbreeding
α
-MyHC-tTA transgenic mice (tetracycline transactivator tTA) with CMV/TRE-COX-2 transgenic mice. Three months after COX-2 induction, mice were subjected to a 30-min coronary occlusion and 24 h of reperfusion. Three different lines (L5, L7, and L8) of iCOX-2 TG mice were studied; in all three lines, infarct size was markedly reduced compared with WT mice: L5 TG/TG 23.4 ± 5.8 vs. WT/WT 48.5 ± 6.1% of risk region; L7 TG/TG 23.2 ± 6.2 vs. WT/WT 53.3 ± 3.6%; and L8 TG/TG 23.5 ± 2.8 vs. WT/WT 52.7 ± 4.6% (
P
< 0.05 for each). COX-2 inhibition with NS-398 completely abolished the cardioprotection provided by COX-2 overexpression. This study for the first time utilizes an inducible cardiac-specific COX-2 overexpression system to examine the role of this enzyme in ischemia/reperfusion injury in vivo. We demonstrate that induced cardiac-specific overexpression of COX-2 exerts a potent cardioprotective effect against myocardial infarction in mice, and that chronic COX-2 overexpression is not associated with any apparent deleterious effects. We also show that PGE2 levels are upregulated in COX-2 overexpressing cardiac tissue, confirming increased enzyme activity. Finally, we have developed a valuable genetic tool to further our understanding of the role of COX-2 in ischemia/reperfusion injury and other settings. The concept that COX-2 is chronically protective has important therapeutic implications for studies of long-term gene therapy aimed at increasing myocardial COX-2 content as well as other COX-2- based strategies.
Intracoronary delivery of c-kit-positive human cardiac stem cells (hCSCs) is a promising approach to repair the infarcted heart, but it is severely limited by the poor survival of donor cells. Cobalt ...protoporphyrin (CoPP), a well known heme oxygenase 1 inducer, has been used to promote endogenous CO generation and protect against ischemia/reperfusion injury. Therefore, we determined whether preconditioning hCSCs with CoPP promotes CSC survival. c-kit-positive, lineage-negative hCSCs were isolated from human heart biopsies. Lactate dehydrogenase release assays demonstrated that preconditioning CSCs with CoPP markedly enhanced cell survival after oxidative stress induced by H2O2, concomitant with up-regulation of heme oxygenase 1, COX-2, and anti-apoptotic proteins (BCL2, BCL2-A1, and MCL-1) and increased phosphorylation of NRF2. Apoptotic cytometric assays showed that pretreatment of CSCs with CoPP enhanced the cells' resistance to apoptosis induced by oxidative stress. Conversely, knocking down HO-1, COX-2, or NRF2 by shRNA gene silencing abrogated the cytoprotective effects of CoPP. Further, preconditioning CSCs with CoPP led to a global increase in release of cytokines, such as EGF, FGFs, colony-stimulating factors, and chemokine ligand. Conditioned medium from cells pretreated with CoPP conferred naive CSCs remarkable resistance to apoptosis, demonstrating that cytokines released by preconditioned cells play a key role in the anti-apoptotic effects of CoPP. Preconditioning CSCs with CoPP also induced an increase in the phosphorylation of Erk1/2, which are known to modulate multiple pro-survival genes. These results potentially provide a simple and effective strategy to enhance survival of CSCs after transplantation and, therefore, their efficacy in repairing infarcted myocardium.
Background: Nothing is known regarding the anti-apoptotic effect of HO-1 on hCSCs.
Results: HO-1 expression induced by CoPP enhances hCSC survival through activation of the ERK/NRF2 signaling pathway and cytokine release.
Conclusion: CoPP is a cytoprotective agent that could improve the efficacy of CSC-based therapies for heart disease.
Significance: Strategies to enhance donor cell survival would have enormous therapeutic implications for patients with ischemic heart disease.
Abstract Pharmacological studies have shown that signal transducers and activators of transcription (STATs) are necessary for the delayed cardioprotection of ischemic preconditioning (PC). However, ...pharmacologic STAT inhibitors are not specific; furthermore, the individual role of STAT3 in late PC remains unknown. The objectives of the study were (i) to create an inducible, cardiac-specific STAT3 knockout mouse; (ii) to verify whether STAT3 deletion has any adverse effects in the short term (~ 1 month); and (iii) to use this novel tool to evaluate the role of STAT3 in the PC-induced upregulation of cardioprotective and anti-apoptotic proteins. We created an inducible, cardiomyocyte-restricted STAT3 deficient mouse ( MCM TG: STAT3 flox/flox ) by interbreeding STAT3 flox/flox mice and tamoxifen-inducible MCM TG mice. Treatment of MCM TG: STAT3 flox/flox mice with tamoxifen resulted in deletion of STAT3 specifically in cardiac myocytes, concomitant with abrogation of ischemic PC-induced Tyr-705 and Ser-727 phosphorylation of STAT3 and increased STAT3 DNA-binding activity. In vehicle-treated MCM TG: STAT3 flox/flox mice, ischemic PC increased the expression of cardioprotective (COX-2 and HO-1) and anti-apoptotic (e.g., Mcl-1, Bcl-xL , c-FLIPL , c-FLIPS ) proteins 24 h later; in contrast, in tamoxifen-treated MCM TG: STAT3 flox/flox mice this increase was completely absent. Deletion of STAT3 had no apparent adverse effects on LV structure or function after 35 days. We have developed a novel inducible, cardiomyocyte-restricted STAT3 deficient mouse that can be used to specifically interrogate the role of this transcription factor in cardiovascular pathophysiology in vivo . Our data demonstrate, for the first time, that recruitment of STAT3 plays an obligatory role in the upregulation of cardioprotective and anti-apoptotic proteins and suggest that STAT3 activation is important in inhibiting both the death receptor pathway (which is modulated by c-FLIPL and c-FLIPS ) and the mitochondrial pathway (which is mediated by Mcl-1 and Bcl-xL ).
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