Prospective randomized trial of direct endomyocardial implantation of bone marrow cells for treatment of severe coronary artery diseases (PROTECT-CAD trial).

AIMS: Experimental studies have demonstrated that bone marrow (BM) cells can induce angiogenesis in ischaemic myocardium. Recently, several non-randomized pilot studies have also suggested that direct BM cells implantation appears to be feasible and safe in patients with severe coronary artery diseases (CAD). METHODS AND RESULTS: We performed a randomized, blinded, and placebo-controlled trial in 28 CAD patients. After BM harvesting, we assigned patients to receive low dose (1 x 10(6) cells/0.1 mL, n = 9), high dose (2 x 10(6) cells/0.1 mL, n = 10) autologous BM cells or control (0.1 mL autologous plasma/injection, n = 9) catheter-based direct endomyocardial injection as guided by electromechanical mapping. Our primary endpoint was the increase in exercise treadmill time and our secondary endpoints were changes in Canadian Cardiovascular Society (CCS) and New York Heart Association (NYHA) class, and myocardial perfusion and left ventricular ejection fraction (LVEF) assessed by single-photon emission computed tomography and magnetic resonance imaging, respectively. A total 422 injections (mean 14.6 +/- 0.7 per patient) were successfully performed at 41 targeted ischaemic regions without any acute complication. Baseline exercise treadmill time was 439 +/- 182 s in controls and 393 +/- 136 s in BM-treated patients, and changed after 6 months to 383 +/- 223s and 464 +/- 196 s [BM treatment effect +0.43 log seconds (+53%), 95% CI 0.11-0.74, P = 0.014]. Compared with placebo injection, BM implantation was associated with a significant increase in LVEF (BM treatment effect +5.4%, 95% CI 0.4-10.3, P = 0.044) and a lower NYHA class (odds ratio for treatment effect 0.12, 95% CI 0.02-0.73, P = 0.021) after 6 months, but CCS reduced similarly in both groups. We observed no acute or long-term complications, including ventricular arrhythmia, myocardial damage, or development of intramyocardial tumour or calcification associated with BM implantation. CONCLUSION: Direct endomyocardial implantation of autologous BM cells significantly improved exercise time, LVEF, and NYHA functional class in patients with severe CAD who failed conventional therapy.     

Lack of Cardiac Nerve Sprouting after Intramyocardial Transplantation of Bone Marrow-Derived Stem Cells in a Swine Model of Chronic Ischemic Myocardium

Previous experimental studies suggested that mesenchymal stem cell transplantation causes cardiac nerve sprouting; however, whether bone marrow (BM)-derived mononuclear cells (MNC) and endothelial progenitor cells (EPC) can also lead to cardiac nerve sprouting and alter gap junction expression remains unclear. We investigated the effect of electroanatomical mapping-guided direct intramyocardial transplantation of BM-MNC (n = 8) and CD31+EPC (n = 8) compared with saline control (n = 8) on cardiac nerve sprouting and gap junction expression in a swine model of chronic ischemic myocardium. At 12 weeks after transplantation, the distribution and density of cardiac nerve sprouting were determined by staining of tyrosine hydroxylase (TH) and growth associated protein 43(GAP-43) and expression of connexin 43 in the targeted ischemic and remote normal myocardium. After 12 weeks, no animal developed sudden death after the transplantation. There were no significant differences in the number of cells with positive staining of TH and GAP-43 in the ischemic and normal myocardium between three groups. Furthermore, expression of connexin 43 was also similar in the ischemic and normal myocardia in each group of animals (P > 0.05). The results of this study demonstrated that intramyocardial BM-derived MNC or EPC transplantation in a large animal model of chronic myocardial ischemia was not associated with increased cardiac nerve sprouting over the ischemic myocardium.     

重组血管内皮生长因子_(165)腺相关病毒对心肌梗死大鼠心功能的影响

目的探讨直接心肌注射基因重组内皮生长因子_(165)腺相关病毒(rAAV-hVEGF_(165))对急性心肌梗死大鼠心功能的影响。方法选择雄性SD大鼠81只,将0.1 ml生理盐水或rAAV-hVEGF_(165)分3点注射于梗死交界处心肌内。根据注射药物的不同随机分为4组:假手术组(15只),心肌梗死组(25只),生理盐水组(25只),血管内皮生长因子(VEGF)组(16只)。注射4周后测定心肌组织VEGF含量、超声心动图参数、梗死面积、微血管数量、心钠素水平。结果 VEGF组大鼠心肌梗死面积较心肌梗死组和生理盐水组明显减小(P<0.05),左心室射血分数明显高于心肌梗死组和生理盐水组(P<0.01),心肌组织VEGF含量较心肌梗死组和生理盐水组有所增加。血管计数显示,VEGF组大鼠较其他3组有更多的新生血管形成(P<0.01)。结论直接心肌注射rAAV-hVEGF_(165)能够明显改善急性心肌梗死大鼠的心功能,缩小梗死面积,促进心肌内新血管的形成。     

Evaluation of the effects of intramyocardial injection of DNA expressing vascular endothelial growth factor (VEGF) in a myocardial infarction model in the rat--angiogenesis and angioma formation

OBJECTIVES: The effects of direct intramyocardial injection of the plasmid encoding vascular endothelial growth factor (phVEGF165) in the border zone of myocardial infarct tissue in rat hearts were investigated. BACKGROUND: Controversy exists concerning the ability of VEGF to induce angiogenesis and enhance coronary flow in the myocardium. METHODS: Sprague-Dawley rats received a ligation of the left coronary artery to induce myocardial infarction (MI). At 33.1 +/- 6.5 days, the rats were injected with phVEGF165 at one location and control plasmid at a second location (500 microg DNA, n = 24) or saline (n = 16). After 33.1 +/- 5.7 days, the hearts were excised for macroscopic and histologic analysis. Regional blood flow ratios were measured in 18 rats by radioactive microspheres. RESULTS: phVEGF165-treated sites showed macroscopic angioma-like structures at the injection site while control DNA and saline injection sites did not. By histology, 21/24 phVEGF165-treated hearts showed increased focal epicardial blood vessel density and angioma-like formation. Quantitative morphometric evaluation in 20 phVEGF165-treated hearts revealed 44.4 +/- 10.5 vascular structures per field in phVEGF165-treated hearts versus 21.4 +/- 4.7 in control DNA injection sites (p < 0.05). Regional myocardial blood flow ratios between the injection site and noninfarcted area did not demonstrate any difference between phVEGF,165-treated hearts (0.9 +/- 0.2) and saline-treated hearts (0.7 +/- 0.1). CONCLUSIONS: Injection of DNA for VEGF in the border zone of MI in rat hearts induced angiogenesis. Angioma formation at the injection sites did not appear to contribute to regional myocardial blood flow, which may be a limitation of gene therapy for this application.     

Transendocardial delivery of autologous bone marrow enhances collateral perfusion and regional function in pigs with chronic experimental myocardial ischemia

OBJECTIVES: We tested the hypothesis that intramyocardial injection of autologous bone marrow (ABM) promotes collateral development in ischemic porcine myocardium. We also defined, in vitro, whether bone marrow (BM) cells secrete vascular endothelial growth factor (VEGF) and macrophage chemoattractant protein-1 (MCP-1). BACKGROUND: The natural processes leading to collateral development are extremely complex, requiring multiple growth factors interacting in concert and in sequence. Because optimal angiogenesis may, therefore, require multiple angiogenic factors, we thought that injection of BM, which contains cells that secrete numerous angiogenic factors, might provide optimal therapeutic angiogenesis. METHODS: Bone marrow was cultured four weeks in vitro. Conditioned medium was assayed for VEGF and MCP-1 and was added to cultured pig aortic endothelial cells (PAEC) to assess proliferation. Four weeks after left circumflex ameroid implantation, freshly aspirated ABM (n = 7) or heparinized saline (n = 7) was injected transendocardially into the ischemic zone (0.2 ml/injection at 12 sites). Echocardiography to assess myocardial thickening and microspheres to assess perfusion were performed at rest and during stress. RESULTS: Vascular endothelial growth factor and MCP-1 concentrations increased in a time-related manner. The conditioned medium enhanced, in a dose-related manner, PAEC proliferation. Collateral flow (ischemic/normal zone X 100) improved in ABM-treated pigs (ABM: 98 +/- 14 vs. 83 +/- 12 at rest, p = 0.001; 89 +/- 18 vs. 78 +/- 12 during adenosine, p = 0.025; controls: 92 +/- 10 vs. 89 +/- 9 at rest, p = 0.49; 78 +/- 11 vs. 77 +/- 5 during adenosine, p = 0.75). Similarly, contractility increased in ABM-treated pigs (ABM: 83 +/- 21 vs. 60 +/- 32 at rest, p = 0.04; 91 +/- 44 vs. 36 +/- 43 during pacing, p = 0.056; controls: 69 +/- 48 vs. 64 +/- 46 at rest, p = 0.74; 65 +/- 56 vs. 37 +/- 56 during pacing, p = 0.23). CONCLUSIONS: Bone marrow cells secrete angiogenic factors that induce endothelial cell proliferation and, when injected transendocardially, augment collateral perfusion and myocardial function in ischemic myocardium.     

冠状动脉内移植自体骨髓单个核细胞和内皮祖细胞对小型猪心肌缺血再灌注损伤的疗效比较

目的比较自体骨髓单个核细胞（BM—MNC）和内皮祖细胞（EPC）移植对小型猪心肌缺血再灌注损伤后修复梗死心肌和改善心功能的疗效。方法23头小型猪心肌缺血再灌注损伤模型分为BM—MNC组[（3．54±0．90）×10^8个细膨头,n=9]、EPC组[（1．16±1．07）×10^7个细胞／头,n=7]以及对照组（n=7）,比较细胞移植前以及移植4周时超声心动图、血液动力学和心肌梗死范围的变化。结果与移植前比较,移植4周时BM-MNC组、EPC组左室射血分数（LVEF）分别降低2％[（68±10）％比（66±7）％,P〉0．05]和0[（69±7）％比（69±8）％,P〉0．05],对照组则降低10％[（70±9）％比（59±7）％,P〈0．05],三组间比较差异有统计学意义（P〈0．05）。LVEF、左室收缩末压（LVESP）、心输出量（CO）和左室等容收缩压力最大上升速率（＋dp／dtmax）的变化值在BM—MNC组和EPC组间的差异无统计学意义（P〉0．05）,而显著小于对照组的变化值（P〈0．05）。舒张末压（LVEDP）和等容舒张压力最大下降速率（-dp／dtmax）在细胞移植前后各组变化不明显（P〉0．05）。EPC和BM—MNC移植的心肌梗死面积均小于对照组[心肌梗死面积百分比分别为[（4．1±0．6）％、（8．4±3．8）％和（11．4±3．2）％,均P〈0．05],EPC组较BM-MNC组有减小的趋势,但差异无统计学意义（P=0．067）。结论心肌缺血再灌注损伤后,自体BM—MNC和EPC移植均可明显改善左室收缩功能,这种作用可能通过减小心肌梗死面积实现。移植EPC与BM-MNC改善心功能的疗效相当,但还需进一步评价。     

Intramyocardial injection of vascular endothelial growth factor gene improves cardiac performance and inhibits cardiomyocyte apoptosis

BACKGROUND: Previous studies suggest that vascular endothelial growth factor (VEGF) is a regulator of naturally occurring angiogenesis. However, whether VEGF plays a role in cardiomyocyte apoptosis is not known. AIM: To investigate the effects of intramyocardial injection of VEGF165 cDNA on cardiac performance and cardiomyocyte apoptosis in a rat model of acute myocardial infarction. METHODS: Forty male Sprague-Dawley rats underwent left coronary artery ligation and were randomised to receive VEGF165 cDNA (treated group) or pcDNA3.1 (control), injected directly into the border zone of the ischaemic myocardium. Twenty rats underwent thoracotomy and injection of pcDNA3.1, without coronary ligation (sham group). Haemodynamic and apoptotic parameters were measured two weeks after injection. RESULTS: Three sham, eight control, and five treated animals died. Haemodynamic parameters and microvessel counts in the treated group were significantly better than in the control (P<0.05 to 0.01). Apoptotic index in the treated group was less than in the control (P<0.01). Caspase-3 activation and mitochondrial cytochrome c release in the treated group were also lower than in the control (P<0.01). VEGF165 cDNA treatment significantly inhibited p53, Fas, Bax, and increased VEGF and Bcl-2 expression in the myocardium. CONCLUSION: Intramyocardial injection of VEGF165 cDNA significantly improved cardiac performance, stimulated angiogenesis and reduced cardiomyocyte apoptosis, in a rat model of acute myocardial infarction.     

Transplantation of adipose derived stromal cells is associated with functional improvement in a rat model of chronic myocardial infarction

AIMS: To determine the effect of transplantation of undifferentiated and cardiac pre-differentiated adipose stem cells compared with bone marrow mononuclear cells (BM-MNC) in a chronic model of myocardial infarction. METHODS: Ninety-five Sprague-Dawley rats underwent left coronary artery ligation and after 1 month received by direct intramyocardial injection either adipose derived stem cells (ADSC), cardiomyogenic cells (AD-CMG) or BM-MNC from enhanced-Green Fluorescent Protein (eGFP) mice. The control group was treated with culture medium. Heart function was assessed by echocardiography and 18F-FDG microPET. Cell engraftment, differentiation, angiogenesis and fibrosis in the scar tissue were also evaluated by (immuno)histochemistry and immunofluorescence. RESULTS: One month after cell transplantation, ADSC induced a significant improvement in heart function (LVEF 46.3+/-9.6% versus 27.7+/-8% pre-transplant) and tissue viability (64.78+/-7.2% versus 55.89+/-6.3% pre-transplant). An increase in the degree of angiogenesis and a decrease in fibrosis were also detected. Although transplantation of AD-CMG or BM-MNC also had a positive, albeit smaller, effect on angiogenesis and fibrosis in the infarcted hearts, this benefit did not translate into a significant improvement in heart function or tissue viability. CONCLUSION: These results indicate that transplantation of adipose derived cells in chronic infarct provides a superior benefit to cardiac pre-differentiated ADSC and BM-MNC.     

Adenoviral gene transfer of FGF-5 to hibernating myocardium improves function and stimulates myocytes to hypertrophy and reenter the cell cycle

Fibroblast growth factors (FGFs) have diverse actions on the myocardium but the importance of stimulating angiogenesis versus direct effects of FGFs on cardiac myocytes is unclear. We used intracoronary injection of a replication-deficient adenoviral construct overexpressing FGF-5 (AdvFGF-5) to improve flow and function in swine with hibernating myocardium. Two-weeks after AdvFGF-5 (n=8), wall-thickening increased from 2.4+/-0.04 to 4.7+/-0.7 mm in hibernating LAD regions (P<0.05) whereas remote wall-thickening was unchanged (6.7+/-0.4 to 5.8+/-0.5 mm). This was associated with small increases in resting flow to dysfunctional myocardium, but flow during adenosine was unchanged (LAD 1.45+/-0.27 versus 1.46+/-0.23 mL/min per g and remote 4.84+/-0.23 versus 4.71+/-0.47 mL/min per g, P=NS). Unexpectedly, animals receiving AdvFGF-5 demonstrated a 29% increase in LV mass over the 2-week period (P<0.05 versus untreated animals with hibernating myocardium and normal shams). Histological analysis confirmed profound myocyte cellular hypertrophy in AdvFGF-5 treated myocardium (19.9+/-0.32 versus 15.2+/-0.92 microm in untreated, P<0.001). Myocytes in the proliferative phase of the cell cycle (Ki-67 staining) increased 7-fold after AdvFGF-5 (2,904+/-405 versus 409+/-233 per 10(6) myocyte nuclei in untreated, P<0.05). Myocyte nuclei in the mitotic phase (phosphorylated histone H3 staining) also increased after AdvFGF-5 (127+/-24 versus 35+/-13 per 10(6) myocyte nuclei in untreated, P<0.05). Thus, rather than angiogenesis, stimulation of hypertrophy and reentry of a small number of myocytes into the mitotic phase of the cell cycle are responsible for the effects of AdvFGF-5 on function. Although additional mechanisms may contribute to the improvement in wall-thickening, overexpression of AdvFGF-5 may afford a way to restore function in hibernating myocardium and ameliorate heart failure in chronic ischemic cardiomyopathy.     

Biochemical mechanisms of hibernation and stunning in the human heart

BACKGROUND: Myocardial hibernation and stunning are characterized by depressed cardiac function in the presence of reduced or normal coronary blood flow. The underlying biochemical mechanisms are widely unknown and only limited data are available in human hearts. METHODS AND RESULTS: Left ventricular transmural myocardial biopsies were obtained from normal and dysfunctional segments of patients undergoing coronary bypass surgery. Segments were classified as hibernating (n=10) or stunned (n=9) using contrast ventriculography and echocardiography, single photon emission computed tomography (SPECT), and positron emission tomography (PET). In each patient, biopsies from normal myocardial segments were used as controls (n=19). Compared to control myocardium, levels of cAMP (3'-5'cyclic adenosine monophosphate, in fmol/mg wet weight, means+/-S.E.M.) were higher in hibernating (673+/-76 versus 518+/-47, P<0.05) but unchanged in stunned myocardium (513+/-73 versus 466+/-97, P>0.05). Protein expression of phospholamban, sarcoendoplasmic Ca(2+)-ATPase 2a, calsequestrin, the inhibitory subunit of troponin, as well as the activation of p38 MAP kinase were not different when compared to controls. However, heat shock protein 72 (Hsp72) was increased 55% in stunned (2.89+/-0.58 versus 1.86+/-0.32, P<0.05) but not in hibernating myocardium (1.68+/-0.34 versus 1.67+/-0.29, P>0.05). CONCLUSIONS: The data from the present study suggest different pathophysiological mechanisms for myocardial hibernation and stunning. Alterations in the homeostasis of cAMP might be a compensatory mechanism in myocardial hibernation, whereas expression of Hsp72 appears to be cardioprotective in human myocardial stunning. Future studies should further elucidate these mechanisms and their potential impact on future therapeutic interventions.     

Percutaneous endocardial transfer and expression of genes to the myocardium utilizing fluoroscopic guidance.

Experimental studies indicate that administration of angiogenic proteins or genes by the epicardial or intracoronary route can stimulate development of new collateral vessels and improve myocardial perfusion. An endocardial catheter-based approach to this therapy would obviate the need for surgery, while preserving the effectiveness of direct intramyocardial administration. Fluoroscopic guidance and prototype, preformed, coaxial catheters were used to examine the feasibility of percutaneous catheter-based adenovirus (Ad)-mediated gene transfer and expression in normal swine myocardium. The feasibility of intramyocardial administration (100 microl/injection) of a radiocontrast agent and black tissue dye to all regions of the left ventricle (septum, anterior, lateral, and inferior wall) was confirmed fluoroscopically and on postmortem examination. Injections of replication-deficient adenovirus (10 injections of 10(11) particle units/100 microl each) coding for beta-galactosidase (Adbetagal) or vascular endothelial growth factor (Ad(GV)VEGF121.10) were administered to the left ventricular free wall to examine endocardial based gene transfer and expression. beta-Galactosidase activity was detected by histochemical staining and quantitative assay in targeted regions of the myocardium. Regional VEGF expression was found to be significantly greater in targeted regions (1.3 +/- 0.4 ng/mg protein) as compared with non-targeted regions (0.3 +/- 0.1 ng/mg protein) or regions injected with control (Adbetagal) virus (0.2 +/- 0.03 ng/mg protein, P < 0.001). Catheter-based Ad mediated endocardial gene transfer and expression is feasible using percutaneous, fluoroscopically guided, preformed, coaxial catheters. This approach should be clinically useful to administer angiogenic genes to the ischemic myocardium.     

经冠脉移植骨髓单个核细胞和间充质干细胞治疗急性心肌梗死的对比实验研究

目的 对比研究经冠脉骨髓单个核细胞（BM-MNC）和间充质干细胞（MSC）移植对实验性急性心肌梗死（AMI）心功能的影响及其机制.方法 选用12只雄性冀中白猪随机分为：正常对照组、AMI模型组、BM-MNC组、MSC组各3只,经导管球囊封闭前降支制作AMI的动物模型,于梗死后1 h直接冠脉球囊成型术后经OTW球囊注入骨髓干细胞.分别于术前及术后4 w经心脏超声检测心功能,4 w后取材行光、电镜病理学检查,实时定量RT-PCR检测心肌血管内皮生长因子（VEGF）和碱性成纤维细胞生长因子（bFGF）mRNA表达.结果 4 w时干细胞组比AMI模型组室壁运动异常指数显著减轻（P＜0.05）、射血分数显著提高（P＜0.01）.与AMI模型组相比：BM-M;NC和MSC组梗死区及梗死边缘区血管数显著增多、BM-MNC组增加比MSC组显著（P＜0.01）,心肌细胞凋亡指数显著降低,BM-MNC组及MSC组间无明显差异（P＜0.01）.干细胞移植组梗死边缘区冠脉血管周围可见异常细胞生长,有毛细血管＂芽生＂现象,可见不成熟的心肌细胞和细胞凋亡.4 w时左室射血分数（LVEF）与心肌血管数成正相关（r=0.694 9,P=0.037 7）,LVEF与心肌细胞凋亡指数成负相关（r=0.913 3,P=0.000 6）.BM-MNC组,心肌梗死区及梗死边缘区VEGF基因表达比其他三组均明显增加（梗死区F=4.23,P=0.045 6,边缘区F=5.66,P=0.022 3）.BM-MNC及MSC组心肌梗死区bFGF基因表达比梗死模型组显著增加（梗死区F=7.49,P=0.010 4）.结论 经冠脉骨髓单个核细胞和间充质干细胞移植均可改善实验性AMI心功能;改善心功能的机理与梗死区及梗死边缘区VEGF及bFGF表达增加,血管密度增加,心肌细胞凋亡减少有关;骨髓单个核细胞移植的促血管增生作用优于间充质干细胞移植.     

Electromagnetic guidance for catheter-based transendocardial injection: a platform for intramyocardial angiogenesis therapy. Results in normal and ischemic porcine models

OBJECTIVES: To test the feasibility of myocardial angiogenic gene expression using a novel catheter-based transendocardial injection system. BACKGROUND: Angiogenesis has been induced by direct injection of growth factors into ischemic myocardium during open-heart surgery. Catheter-based transendocardial injection of angiogenic factors may provide equivalent benefit without need of surgery. METHODS: A new guidance system for intramyocardial therapy utilizes magnetic fields and catheter-tip sensors to locate a position in space and reconstruct three-dimensional left ventricular (LV) electromechanical maps without using fluoroscopy. A retractable 27G needle was coupled with the guidance system for LV transendocardial injection. In 12 pigs, the catheter was used to inject 0.1 ml of methylene-blue (MB) dye and 8 pigs had myocardial injections of adenoviral vector (1 x 10(10) particles per site) containing the LacZ transgene. Ten pigs underwent catheter-based transendocardial injection and six pigs were injected using transepicardial approach with the gene encoding adenovirus vascular endothelial growth factor-121 (Ad.VEGF121; 1 x 10(10) viral particles x 6 sites) and sacrificed at 24 h. Injection sites were identified with ultraviolet light by coinjection of fluorescent beads. RESULTS: Overall, 138 of 152 attempted injection MB tracks (91%) were found after sacrifice. Tissue staining was 7.1+/-2.1 mm in depth and 2.3+/-1.8 mm in width. No animal had pericardial effusion or tamponade. In Ad.LacZ injected animals, gross pathology showed positive staining in injected zones, and histology confirmed positive myocyte staining. Adenovirus vascular endothelial growth factor-121 injected sites showed high levels of VEGF121 production that was of similar magnitude whether injected using the transendocardial (880.4+/-412.2 pg VEGF121/mg protein) or transepicardial (838.3+/-270 pg VEGF121/mg protein) delivery approach (p = 0.62). CONCLUSIONS: Using this magnetic guidance catheter-based navigational system, transgenes can effectively be transfected into designated myocardial sites. Thus, if it is determined that direct intramyocardial injection of angiogenic factors enhances collateral function in patients, this less invasive catheter-based system offers a similar gene delivery efficiency and, thus, may have clear advantages compared with the surgically-based transepicardial injection approach.     

Myocardial gene transfer by selective pressure-regulated retroinfusion of coronary veins: comparison with surgical and percutaneous intramyocardial gene delivery.

OBJECTIVES: We sought to study adenoviral gene delivery using percutaneous selective pressure-regulated retroinfusion and to compare it directly with surgical and percutaneous intramyocardial delivery (PIMD) for the first time. BACKGROUND: Intramyocardial delivery (IMD) has been recommended to be the preferred gene delivery strategy so far. However, surgical and percutaneous intramyocardial injection lead to incomplete retention of the injected viral vectors and to limited spatial myocardial distribution. Percutaneous selective pressure-regulated retroinfusion of the coronary veins was developed recently to provide an effective and more homogenous regional myocardial gene transfer. METHODS: In 15 pigs, adenoviral vectors (Ad2-CMV beta-galactosidase [beta-gal] 5 x 10(9) pfu) were applied via surgical IMD (n = 5), PIMD (n = 5), and selective pressure-regulated retroinfusion (n = 5). Seven days after gene transfer, myocardial beta-gal expression was measured by ELISA. RESULTS: Selective retroinfusion into the anterior cardiac vein substantially increased reporter gene expression (1,039 +/- 79 pg beta-gal/mg protein) in the targeted left anterior descending coronary artery territory when compared with surgical (448 +/- 127, p < 0.05) and PIMD (842 +/- 145, p < 0.05). Both IMD approaches showed an inhomogenous beta-gal expression, particularly along the injection sites, while retroinfusion resulted in a more homogenous transmural gene expression. CONCLUSIONS: Percutaneous selective pressure-regulated retroinfusion compares favorably with surgical and percutaneous intramyocardial injection techniques by providing a more homogenous and even more efficient adenoviral gene delivery.     

Bidirectional role of tumor necrosis factor-alpha in coronary microembolization: progressive contractile dysfunction versus delayed protection against infarction

In patients with unstable angina, plaque rupture and coronary microembolization (ME) can precede complete coronary artery occlusion and impending infarction. ME-induced microinfarcts initiate an inflammatory reaction with increased tumor necrosis factor-alpha (TNF-alpha) expression, resulting in progressive contractile dysfunction. However, TNF-alpha is not only a negative inotrope but can also protect the myocardium against infarction. In anesthetized pigs, we studied whether ME protects against infarction when TNF-alpha expression is increased. ME (group1; n=7) was induced by intracoronary infusion of microspheres (42 microm; 3000 per mL/min inflow). Controls (group 2; n=8) received saline. Groups 3 and 4 (n=4 each) were pretreated with ovine TNF-alpha antibodies (25 mg/kg body weight) 30 minutes before ME or placebo, respectively. Ischemia (90 minutes) was induced 6 hours after ME when TNF-alpha was increased (66+/-21 pg/g wet weight; mean+/-SEM) or after placebo (TNF-alpha, 21+/-10 pg/g; P<0.05). Infarct size (percentage area at risk) was determined after 2 hours of reperfusion (triphenyl tetrazolium chloride staining). ME decreased systolic wall thickening progressively over 6 hours (group 1 versus group 2, 65+/-4% versus 90+/-1%; percentage of baseline; P<0.05). TNF-alpha antibodies attenuated the progressive decrease in systolic wall thickening following ME (group 3, 77+/-5% of baseline; P<0.05 versus group 1) with no effect in controls (group 4; 90+/-8% of baseline). With ME, infarct size was decreased to 18+/-4% versus 33+/-4% in group 2 (P<0.05). The infarct size reduction was abolished by TNF-alpha antibodies (group 3 versus group 4, 29+/-3% versus 35+/-5%). In ME, TNF-alpha is responsible for both progressive contractile dysfunction and delayed protection against infarction.     

Hyperactivity and altered mRNA isoform expression of the Cl(-)/HCO(3)(-) anion-exchanger in the hypertrophied myocardium

OBJECTIVE: The aim was to examine the regulation of the cardiac Na(+)-independent Cl(-)/HCO(3)(-) exchanger (AE) mRNA isoform expression in association to the enhanced AE activity in the hypertrophied myocardium of spontaneously hypertensive rats (SHR). METHODS: AE activity was determined by the initial rates of the pH(i) recovery from imposed intracellular alkalinization (forward mode of exchange) and the pH(i) rise induced by Cl(-) removal (reverse mode). Net HCO(3)(-) (J(HCO(3)(-))) efflux and influx were respectively determined. AE mRNA isoforms were analyzed by Northern blot with specific probes to detect AE1, AE2 and AE3 mRNAs. RESULTS: Initial J(HCO(3)(-)) efflux after imposed alkaline load (pH(i) congruent with 7.5) was higher in SHR than in normotensive WKY rats (3.01+/-0.33, n=7, vs. 0.64+/-0.29 mM/min, n=5, P<0.05). J(HCO(3)(-)) influx induced by Cl(-) deprivation was also increased in SHR, 4.24+/-0.56 mM/min (n=10) versus 2.31+/-0.26 (n=10, P<0.05) in WKY. In arbitrary units, the 4.1-kb AE1 mRNA decreased in SHR (0.15+/-0.01, n=7) compared to WKY (0.29+/-0.06, n=7, P<0.05), whereas the 3.6-kb mRNA did not change. AE2 mRNAs were similarly expressed in WKY and SHR. Cardiac specific AE3 (cAE3) mRNA decreased in SHR, 1.10+/-0.16 arbitrary units (n=8) versus 1.79+/-0.24, (n=8, P<0.05) in WKY. Full length AE3 (flAE3) mRNA increased from 0.69+/-0.06 (WKY, n=8) to 1.25+/-0.19 arbitrary units in SHR (n=8, P<0.05). CONCLUSIONS: The increase in flAE3 mRNA expression in cardiac tissue from the SHR is an adaptive change of the hypertrophied myocardium that might be in connection with the increased activity of the AE.     

Direct epicardial mapping predicts the recovery of left ventricular dysfunction in chronic ischaemic myocardium.

AIMS: This study investigated the hypothesis that direct epicardial bipolar mapping is able to predict the recovery of left ventricular (LV) dysfunction in ischaemic myocardium. METHODS AND RESULTS: In 34 patients with CAD, a maximum of 102 bipolar epicardial electrograms per patient (n=3468 electrograms) were simultaneously recorded with a ventricular jacket array intraoperatively immediately prior to revascularization. Only LV electrograms with good myocardial contact (n=1813, 52+/-14 per patient, mean+/-SD) were analyzed. In accordance to the position of each electrode, segmental myocardial function was assessed by transthoracic echocardiography before and 7+/-2 months (mean+/-SD; range 3-10 months) after CABG using a wall motion score. Preoperatively dysfunctional segments (n=700) were classified as viable (improvement in wall motion score of at least 20% following CABG, n=424) or non-viable (no improvement, n=276). Bipolar voltage was significantly lower in non-viable when compared to viable myocardium (P<0.001, ANOVA) At a cut-off value of 5.9mV, ROC-curve analysis for bipolar voltage (to discriminate between viable and non-viable myocardium) revealed a sensitivity of 83% at a specificity of 83% (area under the ROC-curve of 0.92+/-0.01, mean+/-SE). CONCLUSIONS: Direct epicardial mapping is able to predict the recovery of chronically ischaemic dysfunctional myocardium and thereby proves the presence of myocardial viability.