The Third Universal Definition of Myocardial Infarction(MI) requires cardiac myocyte necrosis with an increase and/or a decrease in a patient's plasma of cardiac troponin(cT n) with at least one cT n measurement g...The Third Universal Definition of Myocardial Infarction(MI) requires cardiac myocyte necrosis with an increase and/or a decrease in a patient's plasma of cardiac troponin(cT n) with at least one cT n measurement greater than the 99 th percentile of the upper normal reference limit during:(1) symptoms of myocardialischemia;(2) new significant electrocardiogram(ECG) ST-segment/T-wave changes or left bundle branch block;(3) the development of pathological ECG Q waves;(4) new loss of viable myocardium or regional wall motion abnormality identified by an imaging procedure; or(5) identification of intracoronary thrombus by angiography or autopsy.Myocardial infarction,when diagnosed,is now classified into five types.Detection of a rise and a fall of troponin are essential to the diagnosis of acute MI.However,high sensitivity troponin assays can increase the sensitivity but decrease the specificity of MI diagnosis.The ECG remains a cornerstone in the diagnosis of MI and should be frequently repeated,especially if the initial ECG is not diagnostic of MI.There have been significant advances in adjunctive pharmacotherapy,procedural techniques and stent technology in the treatment of patients with MIs.The routine use of antiplatelet agents such as clopidogrel,prasugrel or ticagrelor,in addition to aspirin,reduces patient morbidity and mortality.Percutaneous coronary intervention(PCI) in a timely manner is the primary treatment of patients with acute ST segment elevation MI.Drug eluting coronary stents are safe and beneficial with primary coronary intervention.Treatment with direct thrombin inhibitors during PCI is non-inferior to unfractionated heparin and glycoprotein Ⅱb/Ⅲa receptor antagonists and is associated with a significant reduction in bleeding.The intra-coronary use of a glycoprotein Ⅱb/Ⅲa antagonist can reduce infarct size.Pre- and post-conditioning techniques can provide additional cardioprotection.However,the incidence and mortality due to MI continues to be high despite all these recent advances.The ini展开更多
The heart has been considered a post-mitotic organ without regenerative capacity for most of the last century.We review the evidence that led to this hypothesis in the early 1900s and how it was progressively modified...The heart has been considered a post-mitotic organ without regenerative capacity for most of the last century.We review the evidence that led to this hypothesis in the early 1900s and how it was progressively modified,culminating with the report that we renew 50% of our cardiomyocytes during our lifetime.The future of cardiac regenerative therapies is discussed,presenting the difficulties to overcome before repair of the diseased heart can come into clinical practice.展开更多
目的:探讨鹿茸多肽诱导心肌干细胞(CSCs)向心肌细胞分化的机制。方法:从SD大鼠体内分离CSCs,鉴定后培养传代至P3代后,分为空白对照组、5-氮胞苷诱导组(3μmol/L)、鹿茸多肽诱导组(800μg/ml)及其联合诱导组,除空白对照组细胞只加含3%胎...目的:探讨鹿茸多肽诱导心肌干细胞(CSCs)向心肌细胞分化的机制。方法:从SD大鼠体内分离CSCs,鉴定后培养传代至P3代后,分为空白对照组、5-氮胞苷诱导组(3μmol/L)、鹿茸多肽诱导组(800μg/ml)及其联合诱导组,除空白对照组细胞只加含3%胎牛血清的培养液外,其余各组细胞加入含相应诱导剂的培养液,培养14 d。采用免疫组化法检测细胞表面心肌肌钙蛋白T(cTnT)表达,免疫印迹技术检测细胞cTnT、活化复制因子2(ATF-2)和肌细胞增强因子2C(MEF-2C)表达,实时定量聚合酶链式反应技术检测细胞cTnT和转录因子Nkx2.5、GATA4 m RNA表达。结果:成功制得CSCs,纯度>97%。与空白对照组(cTnT呈阴性)比较,各诱导组细胞cTnT呈阳性,cTnT、ATF-2、MEF-2C蛋白表达和cTnT、Nkx2.5、GATA4 m RNA表达均增强(P<0.05)。与5-氮胞苷诱导组比较,鹿茸多肽诱导组细胞cTnT、MEF-2C蛋白表达和cTnT、GATA4 m RNA表达均增强(P<0.05),联合诱导组细胞cTnT、ATF-2、MEF-2C蛋白表达和cTnT、GATA4 m RNA表达均增强(P<0.05)。结论:鹿茸多肽可能通过增强Nkx2.5、GATA4、ATF-2、MEF-2C等转录因子的表达来诱导CSCs向心肌细胞分化。展开更多
AIM: To facilitate engineering of suitable biomaterials to meet the challenges associated with myocardial infarction. METHODS: Poly (glycerol sebacate)/collagen (PGS/ collagen) core/shell fibers were fabricated by cor...AIM: To facilitate engineering of suitable biomaterials to meet the challenges associated with myocardial infarction. METHODS: Poly (glycerol sebacate)/collagen (PGS/ collagen) core/shell fibers were fabricated by core/ shell electrospinning technique, with core as PGS and shell as collagen polymer; and the scaffolds were characterized by scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), contact angle and tensile testing for cardiac tissue engineering. Collagen nanofibers were also fabricated by electrospinning for comparison with core/shell fibers. Studies on cell-scaffold interaction were carriedout using cardiac cells and mesenchymal stem cells (MSCs) co-culture system with cardiac cells and MSCs separately serving as positive and negative controls respectively. The co-culture system was characterized for cell proliferation and differentiation of MSCs into cardiomyogenic lineage in the co-culture environment using dual immunocytochemistry. The co-culture cells were stained with cardiac specific marker proteins like actinin and troponin and MSC specific marker protein CD 105 for proving the cardiogenic differentiation of MSCs. Further the morphology of cells was analyzed using SEM.RESULTS: PGS/collagen core/shell fibers, core is PGS polymer having an elastic modulus related to that of cardiac fibers and shell as collagen, providing natural environment for cellular activities like cell adhesion, proliferation and differentiation. SEM micrographs of electrospun fibrous scaffolds revealed porous, beadless, uniform fibers with a fiber diameter in the range of 380 ± 77 nm and 1192 ± 277 nm for collagen fibers and PGS/collagen core/shell fibers respectively. The obtained PGS/collagen core/shell fibrous scaffolds were hydrophilic having a water contact angle of 17.9 ± 4.6° compared to collagen nanofibers which had a contact angle value of 30 ± 3.2°. The PGS/collagen core/shell fibers had mechanical properties comparable to that of native heart muscle with a young's modulus of 4.展开更多
Over the last years, stem cell therapy has emerged asan inspiring alternative to restore cardiac function after myocardial infarction. A large body of evidence has been obtained in this field but there is no conclusiv...Over the last years, stem cell therapy has emerged asan inspiring alternative to restore cardiac function after myocardial infarction. A large body of evidence has been obtained in this field but there is no conclusive data on the efficacy of these treatments. Preclinical studies and early reports in humans have been encouraging and have fostered a rapid clinical translation, but positive results have not been uniformly observed and when present, they have been modest. Several types of stem cells, manufacturing methods and delivery routes have been tested in different clinical settings but direct comparison between them is challenging and hinders further research. Despite enormous achievements, major barriers have been found and many fundamental issues remain to be resolved. A better knowledge of the molecular mechanisms implicated in cardiac development and myocardial regeneration is critically needed to overcome some of these hurdles. Genetic and pharmacological priming together with the discovery of new sources of cells have led to a "second generation" of cell products that holds an encouraging promise in cardiovascular regenerative medicine. In this report, we review recent advances in this field focusing on the new types of stem cells that are currently being tested in human beings and on the novel strategies employed to boost cell performance in order to improve cardiac function and outcomes after myocardial infarction.展开更多
基金Supported by Research facilities at the James A Haley VA Hospitalin part+3 种基金Grants from the Florida King Biomedical Research Programthe Muscular Dystrophy Associationthe Robert O Law Foundationthe Cornelius Foundation
文摘The Third Universal Definition of Myocardial Infarction(MI) requires cardiac myocyte necrosis with an increase and/or a decrease in a patient's plasma of cardiac troponin(cT n) with at least one cT n measurement greater than the 99 th percentile of the upper normal reference limit during:(1) symptoms of myocardialischemia;(2) new significant electrocardiogram(ECG) ST-segment/T-wave changes or left bundle branch block;(3) the development of pathological ECG Q waves;(4) new loss of viable myocardium or regional wall motion abnormality identified by an imaging procedure; or(5) identification of intracoronary thrombus by angiography or autopsy.Myocardial infarction,when diagnosed,is now classified into five types.Detection of a rise and a fall of troponin are essential to the diagnosis of acute MI.However,high sensitivity troponin assays can increase the sensitivity but decrease the specificity of MI diagnosis.The ECG remains a cornerstone in the diagnosis of MI and should be frequently repeated,especially if the initial ECG is not diagnostic of MI.There have been significant advances in adjunctive pharmacotherapy,procedural techniques and stent technology in the treatment of patients with MIs.The routine use of antiplatelet agents such as clopidogrel,prasugrel or ticagrelor,in addition to aspirin,reduces patient morbidity and mortality.Percutaneous coronary intervention(PCI) in a timely manner is the primary treatment of patients with acute ST segment elevation MI.Drug eluting coronary stents are safe and beneficial with primary coronary intervention.Treatment with direct thrombin inhibitors during PCI is non-inferior to unfractionated heparin and glycoprotein Ⅱb/Ⅲa receptor antagonists and is associated with a significant reduction in bleeding.The intra-coronary use of a glycoprotein Ⅱb/Ⅲa antagonist can reduce infarct size.Pre- and post-conditioning techniques can provide additional cardioprotection.However,the incidence and mortality due to MI continues to be high despite all these recent advances.The ini
文摘The heart has been considered a post-mitotic organ without regenerative capacity for most of the last century.We review the evidence that led to this hypothesis in the early 1900s and how it was progressively modified,culminating with the report that we renew 50% of our cardiomyocytes during our lifetime.The future of cardiac regenerative therapies is discussed,presenting the difficulties to overcome before repair of the diseased heart can come into clinical practice.
文摘目的:探讨鹿茸多肽诱导心肌干细胞(CSCs)向心肌细胞分化的机制。方法:从SD大鼠体内分离CSCs,鉴定后培养传代至P3代后,分为空白对照组、5-氮胞苷诱导组(3μmol/L)、鹿茸多肽诱导组(800μg/ml)及其联合诱导组,除空白对照组细胞只加含3%胎牛血清的培养液外,其余各组细胞加入含相应诱导剂的培养液,培养14 d。采用免疫组化法检测细胞表面心肌肌钙蛋白T(cTnT)表达,免疫印迹技术检测细胞cTnT、活化复制因子2(ATF-2)和肌细胞增强因子2C(MEF-2C)表达,实时定量聚合酶链式反应技术检测细胞cTnT和转录因子Nkx2.5、GATA4 m RNA表达。结果:成功制得CSCs,纯度>97%。与空白对照组(cTnT呈阴性)比较,各诱导组细胞cTnT呈阳性,cTnT、ATF-2、MEF-2C蛋白表达和cTnT、Nkx2.5、GATA4 m RNA表达均增强(P<0.05)。与5-氮胞苷诱导组比较,鹿茸多肽诱导组细胞cTnT、MEF-2C蛋白表达和cTnT、GATA4 m RNA表达均增强(P<0.05),联合诱导组细胞cTnT、ATF-2、MEF-2C蛋白表达和cTnT、GATA4 m RNA表达均增强(P<0.05)。结论:鹿茸多肽可能通过增强Nkx2.5、GATA4、ATF-2、MEF-2C等转录因子的表达来诱导CSCs向心肌细胞分化。
基金Supported by NRF-Technion, No. R-398-001-065-592Ministry of Education, No. R-265-000-318-112NUSNNI, National University of Singapore
文摘AIM: To facilitate engineering of suitable biomaterials to meet the challenges associated with myocardial infarction. METHODS: Poly (glycerol sebacate)/collagen (PGS/ collagen) core/shell fibers were fabricated by core/ shell electrospinning technique, with core as PGS and shell as collagen polymer; and the scaffolds were characterized by scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), contact angle and tensile testing for cardiac tissue engineering. Collagen nanofibers were also fabricated by electrospinning for comparison with core/shell fibers. Studies on cell-scaffold interaction were carriedout using cardiac cells and mesenchymal stem cells (MSCs) co-culture system with cardiac cells and MSCs separately serving as positive and negative controls respectively. The co-culture system was characterized for cell proliferation and differentiation of MSCs into cardiomyogenic lineage in the co-culture environment using dual immunocytochemistry. The co-culture cells were stained with cardiac specific marker proteins like actinin and troponin and MSC specific marker protein CD 105 for proving the cardiogenic differentiation of MSCs. Further the morphology of cells was analyzed using SEM.RESULTS: PGS/collagen core/shell fibers, core is PGS polymer having an elastic modulus related to that of cardiac fibers and shell as collagen, providing natural environment for cellular activities like cell adhesion, proliferation and differentiation. SEM micrographs of electrospun fibrous scaffolds revealed porous, beadless, uniform fibers with a fiber diameter in the range of 380 ± 77 nm and 1192 ± 277 nm for collagen fibers and PGS/collagen core/shell fibers respectively. The obtained PGS/collagen core/shell fibrous scaffolds were hydrophilic having a water contact angle of 17.9 ± 4.6° compared to collagen nanofibers which had a contact angle value of 30 ± 3.2°. The PGS/collagen core/shell fibers had mechanical properties comparable to that of native heart muscle with a young's modulus of 4.
文摘Over the last years, stem cell therapy has emerged asan inspiring alternative to restore cardiac function after myocardial infarction. A large body of evidence has been obtained in this field but there is no conclusive data on the efficacy of these treatments. Preclinical studies and early reports in humans have been encouraging and have fostered a rapid clinical translation, but positive results have not been uniformly observed and when present, they have been modest. Several types of stem cells, manufacturing methods and delivery routes have been tested in different clinical settings but direct comparison between them is challenging and hinders further research. Despite enormous achievements, major barriers have been found and many fundamental issues remain to be resolved. A better knowledge of the molecular mechanisms implicated in cardiac development and myocardial regeneration is critically needed to overcome some of these hurdles. Genetic and pharmacological priming together with the discovery of new sources of cells have led to a "second generation" of cell products that holds an encouraging promise in cardiovascular regenerative medicine. In this report, we review recent advances in this field focusing on the new types of stem cells that are currently being tested in human beings and on the novel strategies employed to boost cell performance in order to improve cardiac function and outcomes after myocardial infarction.
