摘要:

&NA;Restenosis after percutaneous coronary intervention continues to be a serious problem in clinical cardiology. Recent advances in nanoparticle technology have enabled us to deliver an antiproliferative drug selectively to the balloon‐injured artery for a longer time. NK911, which is a core‐shell nanoparticle of polyethyleneglycol‐based block copolymer encapsulating doxorubicin, accumulates in vascular lesions with increased permeability. We first confirmed that balloon injury caused a marked and sustained increase in vascular permeability (as evaluated by Evans blue staining) for a week in the rat carotid artery. We then observed that intravenous administration of just 3 times of NK911, but not doxorubicin alone, significantly inhibited the neointimal formation of the rat carotid artery at 4 weeks after the injury in both a single‐ and double‐injury model. Immunostaining demonstrated that the effect of NK911 was due to inhibition of vascular smooth muscle proliferation but not to enhancement of apoptosis or inhibition of inflammatory cell recruitment. Measurement of vascular concentrations of doxorubicin confirmed the effective delivery of the agent to the balloon‐injured artery by NK911 in both a single‐ and double‐injury model. RNA protection assay demonstrated that NK911 inhibited expression of several cytokines but not that of apoptosis‐related molecules. NK911 was well tolerated without any adverse systemic effects. These results suggest that nanoparticle technology to target vascular lesions with increased permeability is a promising and safe approach for the prevention of restenosis after balloon injury. The full text of this article is available athttp://www.circresaha.org.(Circ Res.2003;92:e62‐e69.)

ISSN:0009-7330    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0009-7330    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0009-7330    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0009-7330    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0009-7330    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

&NA;We tested the hypothesis that myocyte loss in failing human hearts occurs by different mechanisms: apoptosis, oncosis, and autophagic cell death. Explanted hearts from 19 patients with idiopathic dilated cardiomyopathy (EF≤20%) and 7 control hearts were analyzed. Myocyte apoptosis revealed by caspase‐3 activation and TUNEL staining occurred at a rate of 0.002±0.0005% (P<0.05 versus control) and oncosis assessed by complement 9 labeling at 0.06±0.001% (P<0.05). Cellular degeneration including appearance of ubiquitin containing autophagic vacuoles and nuclear disintegration was present at the ultrastructural level. Nuclear and cytosolic ubiquitin/protein accumulations occurred at 0.08±0.004% (P<0.05). The ubiquitin‐activating enzyme E1 and the ligase E3 were not different from control. In contrast, ubiquitin mRNA levels were 1.8‐fold (P<0.02) elevated, and the conjugating enzyme E2 was 2.3‐fold upregulated (P<0.005). The most important finding, however, is the 2.3‐fold downregulation of the deubiquitination enzyme isopeptidase‐T and the 1.5‐fold reduction of the ubiquitin‐fusion degradation system‐1, which in conjunction with unchanged proteasomal subunit levels and proteasomal activity results in massive storage of ubiquitin/protein complexes and in autophagic cell death. A 2‐fold decrease of cathepsin D might be an additional factor responsible for the accumulation of ubiquitin/protein conjugates. It is concluded that in human failing hearts apoptosis, oncosis, and autophagy act in parallel to varying degrees. A disturbed balance between a high rate of ubiquitination and inadequate degradation of ubiquitin/protein conjugates may contribute to autophagic cell death. Together, these different types of cell death play a significant role for myocyte disappearance and the development of contractile dysfunction in failing hearts.(Circ Res.2003;92:715–724.)

ISSN:0009-7330    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

&NA;Biomechanical stress on the heart results in activation of numerous signaling cascades, leading to cardiomyocyte hypertrophy, apoptosis, and ultimately, heart failure. The Ca2+‐dependent phosphatase calcineurin is an essential mediator of cardiac hypertrophy, and in most but not all studies, calcineurin inhibition attenuated cardiac hypertrophy in vivo. However, calcineurin inhibition has been reported to have adverse effects on cardiac remodeling and cardiomyocyte apoptosis. Calcineurin regulates the activity of a number of downstream targets, including the transcription factors NFAT, MEF2, and NF‐&kgr;B, and the apoptotic factor Bad. To evaluate the contribution of NFAT activation by calcineurin to cardiomyocyte responses to hypertrophic stimulation, we used adenovirus to express VIVIT, a selective peptide inhibitor of calcineurin‐mediated NFAT activation. We found that selective NFAT inhibition during phenylephrine stimulation inhibited hypertrophy but resulted in increased cardiomyocyte apoptosis. In contrast, nonselective inhibition of calcineurin by cyclosporin A did not cause cardiomyocyte apoptosis after phenylephrine stimulation. Cyclosporin A suppressed the effect of VIVIT on cardiomyocyte apoptosis. These results demonstrate that during phenylephrine stimulation calcineurin activates both pro‐ and antiapoptotic pathways in cardiomyocytes, and that NFAT activity is a critical component of the antiapoptotic pathway that regulates whether the outcome of calcineurin activation is cardiomyocyte apoptosis or survival.(Circ Res.2003;92:725–731.)

ISSN:0009-7330    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

&NA;—Endothelial cells express tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) receptors, but the function of TRAIL in endothelial cells is not completely understood. We explored the role of TRAIL in regulation of key intracellular signal pathways in endothelial cells. The addition of TRAIL to primary human endothelial cells increased phosphorylation of endothelial nitric oxide synthase (eNOS), NOS activity, and NO synthesis. Moreover, TRAIL induced cell migration and cytoskeleton reorganization in an NO‐dependent manner. TRAIL did not activate the NF‐&kgr;B or COX‐2 pathways in endothelial cells. Instead, TRAIL increased prostanoid production (PGE2=PGI2>TXA2), which was preferentially inhibited by the COX‐1 inhibitor SC‐560. Because NO and prostanoids play a crucial role in the state of blood vessel vasodilatation and angiogenesis, our data suggest that TRAIL might play an important role in endothelial cell function.(Circ Res.2003;92:732–740.)

ISSN:0009-7330    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

&NA;—Although the inducible isoform of NO synthase (iNOS) mediates late preconditioning (PC), it is unknown whetheriNOSgene transfer can replicate the cardioprotective effects of late PC, and the role of this protein in myocardial ischemia is controversial. Thus, the cDNA for humaniNOSwas cloned behind the Rous sarcoma virus (RSV) promoter to create adenovirus (Ad) 5/iNOS lacking E1, E2a, and E3 regions. Intramyocardial injection of Ad5/iNOS in mice increased local iNOS protein expression and activity and markedly reduced infarct size. The infarct‐sparing effects of Ad5/iNOS were at least as powerful as those of ischemic PC. The increased iNOS expression was associated with increased cyclooxygenase‐2 (COX‐2) protein expression and prostanoid levels. Pretreatment with the COX‐2‐selective inhibitor NS‐398 completely abrogated the infarct‐sparing actions of Ad5/iNOS, demonstrating that COX‐2 is an obligatory downstream effector of iNOS‐dependent cardioprotection. We conclude that gene transfer of iNOS (an enzyme commonly thought to be detrimental) affords powerful cardioprotection the magnitude of which is equivalent to that of late PC. This is the first report that upregulation of iNOS, in itself, is sufficient to reduce infarct size. The results provide proof‐of‐principle for gene therapy against ischemia/reperfusion injury, which increases local myocardial NO synthase levels without the need for continuous intravenous infusion of NO donors and without altering systemic hemodynamics. The data also reveal the existence of a close coupling between iNOS and COX‐2, whereby induction of the former enzyme leads to secondary induction of the latter, which in turn mediates the cytoprotective effects of iNOS. We propose that iNOS and COX‐2 form a stress‐responsive functional module that mitigates ischemia/reperfusion injury. (Circ Res. 2003;92:741–748.)

ISSN:0009-7330    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

&NA;—In the development of a functional myocardium and formation of the coronary vasculature, epicardium‐derived cells play an essential role. The proepicardial organ contributes to the developing coronary system by delivering mural cells to the endothelium‐lined vessels. In search of genes that regulate the behavior of (pro)epicardial cells, the Ets‐1 and Ets‐2 transcription factors stand out as strong candidates. In the present study, the hypothesis that Ets transcription factors have a role in proper coronary and myocardial development was tested via antisense technology, by targetingEts‐1andEts‐2mRNAs to downregulate protein expression in chicken embryos. The results suggest that hereby the development of the coronary system is hampered, primarily by defects in the process of epithelial‐mesenchymal transformation of the mesothelia of the primary and secondary heart fields. This was indicated by a lack of periarterial and epicardial mesenchyme, of peripheral coronary smooth muscle cells, and changes in myocardial morphology. A defect in myocardial perfusion caused by the absence of one or both coronary ostia seems to be “solved” by the development of numerous small fistulae connecting the ventricular lumen with the subepicardially located coronary vessels. The presence of coronary vascular aberrations in the antisense‐Etsphenotype enabled us for the first time to study abnormal coronary development in a model that is not lethal to the embryo.(Circ Res.2003;92:749–756.)

ISSN:0009-7330    

出版商:OVID    

年代:2003

数据来源: OVID