Therapeutic angiogenesis with bone marrow--derived stem cells

Despite that advances in medical treatment and interventional procedures have reduced the mortality rate in patients with coronary artery disease, the number of patients with refractory myocardial ischemia and congestive heart failure is rapidly increasing. Experimental studies have demonstrated that bone marrow (BM) contains adult stem cells that can induce neovascularization and improve heart function in ischemic myocardium. Recent insights into the understanding of the mechanisms involved in proliferation, recruitment, mobilization, and incorporation of BM-derived stem cells into the myocardium and blood vessels have prompted development of cellular transplantation therapy for heart diseases refractory to conventional therapy. Initial preliminary clinical studies indicated potential clinical benefit of BM therapy in patients with acute myocardial infarction and chronic myocardial ischemia. Nevertheless, many obstacles remain, such as long-term safety and optimal timing and treatment strategies for BM cell therapy, and these issues need to be addressed in rationally designed, randomized clinical trials.     

斑点追踪技术评价犬急性心肌缺血及再灌注心内膜下心肌和心外膜下心肌径向应变

目的应用斑点追踪技术检测犬急性心肌缺血及再灌注不同时间点心内膜下心肌和心外膜下心肌的径向应变。方法选取20只健康成年杂种犬,结扎左冠状动脉第一对角支,分别对结扎前、结扎即刻、60、120和180min及再灌注即刻、60和120min基底水平、乳头肌水平和心尖水平心内膜下和心外膜下心肌的径向应变进行比较。结果在急性缺血过程中,基底水平心肌起代偿作用,其径向应变上升;乳头肌水平和心尖水平心肌下降明显,心尖水平心肌甚至出现反向运动。在急性缺血及再灌注过程中,心内膜下心肌对缺血更加敏感。再灌注后,乳头肌水平和心尖水平心内膜下和心外膜下心肌及跨壁的径向应变仍低于基础状态。结论斑点追踪技术可以评价犬局部及整体心脏功能,并判断急性心肌缺血的透壁程度。     

The recombinant bifunctional protein αCD133–GPVI promotes repair of the infarcted myocardium in mice

Background:  Bone‐marrow‐derived progenitor cells are important in myocardial repair mechanisms following prolonged ischemia. Cell‐based therapy of diseased myocardium is limited by a low level of tissue engraftment. Objectives:  The aim of this study was the development of the bifunctional protein αCD133–glycoprotein (GP)VI as an effective treatment for supporting vascular and myocardial repair mechanisms. Results:  We have generated and characterized a bifunctional molecule (αCD133–GPVI) that binds both to the subendothelium of the injured microvasculature and to CD133⁺ progenitor cells with high affinity. αCD133–GPVI enhances progenitor cell adhesion to extracellular matrix proteins and differentiation into mature endothelial cells. In vivo studies showed that αCD133–GPVI favors adhesion of circulating progenitor cells to the injured vessel wall (intravital microscopy). Also, treatment of mice undergoing experimental myocardial infarction with αCD133–GPVI‐labeled progenitor cells reduces infarction size and preserves myocardial function. Conclusions:  The bifunctional trapping protein αCD133–GPVI represents a novel and promising therapeutic option for limiting heart failure of the ischemic myocardium.     

心肌及冠状动脉内移植骨髓单个核细胞对猪缺血心肌侧支血管的生成

背景:目前有研究表明,心肌内直接注射骨髓单个核细胞可以使心肌梗死瘢痕区血管新生,改善缺血心肌血供。目的:观察心肌内及冠状动脉内移植自体骨髓单个核细胞对猪急性心肌梗死后缺血心肌侧支血管生成的作用。方法:22只小型猪制备急性心肌梗死模型后分为4组:心肌内移植组造模后即刻在缺血心肌内注射自体骨髓单个核细胞悬液;心肌内对照组同样方法即刻心肌内注射Hank’s平衡盐溶液;冠状动脉内移植组在造模后1周,左冠状动脉内注射自体骨髓单个核细胞悬液;冠状动脉对照组在造模后1周,同样方法左冠状动脉内注射Hank’s平衡盐溶液。结果与结论:心肌内及冠状动脉内移植骨髓单个核细胞后1周,血清碱性成纤维细胞生长因子及血管内皮细胞生长因子水平差异无显著性意义,但明显高于各自对照组(P<0.01);移植后4周,心肌内移植组与冠状动脉内移植组小血管密度差异无显著性意义,但明显高于各自对照组(P<0.01);左室舒张末压差异无显著性意义,但明显低于各组对照组(P<0.01)。提示心肌内及冠状动脉内移植骨髓单个核细胞均有助于促进猪缺血心肌血管新生及侧支循环形成。     

干细胞移植治疗缺血性心脏病：临床应用的可行性与安全性

背景：干细胞移植到受损的心脏组织,可以大量分化为心肌细胞,这项研究为缺血性心脏病治疗带来新的希望。目的：探讨干细胞移植治疗缺血性心脏病的可行性与安全性。方法：分析干细胞移植治疗缺血性心脏病安全性和可行性的多种试验方法。REPAIR-AMI试验是一项分析急性心肌梗死后即刻冠脉内移植骨髓祖细胞治疗效果的随机双盲、安慰剂对照的多中心研究;MAGICCell-3-DES试验是评价粒细胞集落刺激因子动员的干细胞疗法的安全性和冠脉内注射动员的外周血干细胞对急性心肌梗死和陈旧性心肌梗死的效果;BOOST试验是心肌梗死后经冠脉移植自体骨髓细胞的随机对照研究。PROTECT-CAD试验是一项随机、对照的直接将干细胞注入心肌治疗慢性缺血性心肌病的临床试验。结果与结论：干细胞移植可以改善左心室的收缩功能和舒张功能以及冠脉血流储备,相关研究也得到验证。对于干细胞移植治疗缺血性心脏病,可以增加左室射血分数,临床事件较少,在药物洗脱支架治疗的基础上,干细胞治疗并不增加再狭窄风险。干细胞移植治疗缺血性心脏病安全可行,未来还需要进行大样本、长时间的大规模多中心的随机对照研究,来进一步评价其疗效和风险。     

Revascularization of ischemic tissues by PDGF-CC via effects on endothelial cells and their progenitors

The angiogenic mechanism and therapeutic potential of PDGF-CC, a recently discovered member of the VEGF/PDGF superfamily, remain incompletely characterized. Here we report that PDGF-CC mobilized endothelial progenitor cells in ischemic conditions; induced differentiation of bone marrow cells into ECs; and stimulated migration of ECs. Furthermore, PDGF-CC induced the differentiation of bone marrow cells into smooth muscle cells and stimulated their growth during vessel sprouting. Moreover, delivery of PDGF-CC enhanced postischemic revascularization of the heart and limb. Modulating the activity of PDGF-CC may provide novel opportunities for treating ischemic diseases.     

AMP-activated protein kinase: the guardian of cardiac energy status

Several years ago it was proposed that the AMP-activated protein kinase cascade might protect cells against stresses that deplete cellular ATP. Young et al. have now directly tested this by studying the effects of ischemia and reperfusion in perfused hearts from mice expressing a dominant-negative mutant that suppresses the kinase activity in cardiac muscle. Compared with control hearts, the mutant hearts showed clear evidence for increased necrotic damage and increased apoptosis. These findings may have implications for the treatment of ischemic heart disease.     

Allopurinol enhanced adenine nucleotide repletion after myocardial ischemia in the isolated rat heart.

Allopurinol, a competitive inhibitor of xanthine oxidase, has been shown to have a protective effect on ischemic myocardium, but its mechanism of action remains controversial. We used an isolated rat heart preparation to test the hypothesis that allopurinol could restore adenosine triphosphate (ATP) levels and improve the recovery of left ventricular function after global myocardial ischemia. Hearts were equilibrated for 30 min, subjected to 10 min of global, normothermic (37 degrees C) ischemia, and reperfused for 15, 30, and 60 min. Hearts treated with allopurinol (100 microM) exhibited greater ATP levels and improved function during reperfusion than did untreated control hearts. Hearts treated with hypoxanthine (100 microM), the substrate for xanthine oxidase, also showed increased ATP and functional recovery compared with controls. These results suggest that allopurinol may protect the globally ischemic myocardium by enhancing the salvage of hypoxanthine for reincorporation into adenine nucleotides.     

Effects of diltiazem on glycolysis and oxidative metabolism in the ischemic and ischemic/reperfused heart.

We have recently demonstrated that calcium channel blockers can protect the ischemic myocardium at concentrations which do not decrease myocardial workload or metabolic demand before ischemia. In this study, we extended these observations by determining what effect the calcium channel blocker, diltiazem, has on overall myocardial energy substrate metabolism in aerobic, ischemic and reperfused ischemic hearts. Isolated working rat hearts were perfused at a 11.5-mm Hg preload, 80-mm Hg afterload, with Krebs-Henseleit buffer containing 11 mM glucose, 1.2 mM palmitate and 500 microU/ml insulin. Glycolysis and glucose oxidation rates were determined in aerobic and reperfused ischemic hearts perfused with [3H]/[14C]glucose, whereas fatty acid oxidation rates were determined under similar conditions in hearts perfused with [14C]palmitate. Addition of diltiazem (0.8 microM) before subjecting hearts to a 30-min period of global no-flow ischemia resulted in a significant improvement in recovery of mechanical function (heart rate x developed pressure during reperfusion recovered to 28 and 53% of preischemic levels, in control and diltiazem-treated hearts, respectively). If diltiazem was added at reperfusion, no improvement of functional recovery was seen. Addition of diltiazem before or after ischemia had no effect on palmitate or glucose oxidation during reperfusion, but did significantly decrease rates of glycolysis during reperfusion. In hearts subjected to low-flow ischemia (coronary flow = 0.5 ml/min), diltiazem significantly decreased glycolytic rates during ischemia (glycolytic rates were 2.09 +/- 0.25 and 1.58 +/- 0.28 mumol/min.g dry wt. in control and diltiazem-treated hearts, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

内皮祖细胞生物学特征及其临床应用

背景：内皮祖细胞已经广泛用于研究缺血性疾病,能促进内皮再生、血管修复及组织中新生血管形成.目的：综述内皮祖细胞生物学特征及其临床应用的研究进展.方法：应用计算机检索1997-01/2010-12 PubMed数据库相关文章,检索词为＂endothelial progenitor cells,ischemic cerebrovascular disease,early endothelial progenitor cells,late endothelial progenitor cells＂,共检索到文献219篇,最终纳入符合标准的文献28篇.结果与结论：内皮祖细胞定居于成体骨髓,现已证实胎肝、人脐血、成人外周血及骨髓中均存在,且人脐血、外周血中的内皮祖细胞均来源于骨髓.此外在心脏、血管、脂肪组织和骨骼肌等外周组织中也发现内皮祖细胞的存在.内皮祖细胞具有促进内皮再生及血管修复的功能,能促进组织中新生血管形成,在防治血管成形术后再狭窄等血管性疾病中发挥重要作用,其中晚期内皮祖细胞比早期内皮祖细胞更易形成毛细血管,在干细胞移植临床应用于缺血性脑卒中具有广泛的前景.     

Multipotent adult progenitor cell transplantation increases vascularity and improves left ventricular function after myocardial infarction

Progressive contractile dysfunction of viable myocardium that surrounds a large infarct leads to heart failure following acute myocardial infarction (AMI). Experimental evidence indicates that cellular transplantation may improve the left ventricular (LV) contractile performance, even though the underlying mechanisms remain undefined. Here, we compared the effect of transplantation of murine multipotent adult progenitor cells (MAPCs), a population of adult bone marrow-derived cells that differentiate into cells of mesodermal, endodermal and ectodermal origin, with murine bone marrow cells (BMCs) or fibroblasts on post-infarct cardiac function by peri-infarct injection after coronary artery ligation in mice. We demonstrate that, in contrast to the other cell populations, transplantation of MAPCs significantly improved LV contractile function for at least 8 weeks post-transplantation and, although BMCs reduced infarct size, the decrease in scar size was substantially greater in MAPC-treated hearts. As neither MAPCs nor BMCs were present beyond 1 week, the beneficial effect was not due to differentiation and direct contribution of MAPCs to the vascular or cardiomyocyte compartment. Significantly more inflammatory cells were present in MAPC- than BMC-treated hearts at 1 week, which was accompanied by increased vascularity 8 weeks post-transplantation. We hypothesize that MAPCs indirectly contributed to these effects, by secreting inflammatory [monocyte chemoattractant protein-1 (MCP)-1], and vascular growth factors [vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF)-BB, and transforming growth factor (TGF)beta(1)), and others, resulting in increased angiogenensis and cardioprotection.     

Cardioprotective c-kit+ cells are from the bone marrow and regulate the myocardial balance of angiogenic cytokines

Clinical trials of bone marrow stem/progenitor cell therapy after myocardial infarction (MI) have shown promising results, but the mechanism of benefit is unclear. We examined the nature of endogenous myocardial repair that is dependent on the function of the c-kit receptor, which is expressed on bone marrow stem/progenitor cells and on recently identified cardiac stem cells. MI increased the number of c-kit+ cells in the heart. These cells were traced back to a bone marrow origin, using genetic tagging in bone marrow chimeric mice. The recruited c-kit+ cells established a proangiogenic milieu in the infarct border zone by increasing VEGF and by reversing the cardiac ratio of angiopoietin-1 to angiopoietin-2. These oscillations potentiated endothelial mitogenesis and were associated with the establishment of an extensive myofibroblast-rich repair tissue. Mutations in the c-kit receptor interfered with the mobilization of the cells to the heart, prevented angiogenesis, diminished myofibroblast-rich repair tissue formation, and led to precipitous cardiac failure and death. Replacement of the mutant bone marrow with wild-type cells rescued the cardiomyopathic phenotype. We conclude that, consistent with their documented role in tumorigenesis, bone marrow c-kit+ cells act as key regulators of the angiogenic switch in infarcted myocardium, thereby driving efficient cardiac repair.     

Ex vivo reversal of heparin-mediated cardioprotection by heparinase after ischemia and reperfusion.

Glycosaminoglycans, including heparin, have been demonstrated both in vitro and in vivo to protect the ischemic myocardium against reperfusion injury. In the present study, we sought to determine whether the cardioprotective effects of heparin administration could be reversed by the heparin-degrading enzyme heparinase. New Zealand white rabbits were pretreated with heparin (300 U/kg i.v.) or vehicle (saline). Two hours after treatment, hearts were removed, perfused on a Langendorff apparatus, and subjected to 25 min of global ischemia, followed by 45 min of reperfusion. Hemodynamic variables were obtained before ischemia (baseline) and every 10 min throughout the reperfusion period. Compared with vehicle-treated rabbits, the left ventricular end-diastolic and left ventricular developed pressures were improved significantly (p <.05) in the heparin-treated group. Ex vivo administration of heparinase (5 U/ml) immediately before the onset of global ischemia was associated with a reversal of the heparin-mediated cardioprotection. The uptake of a radiolabeled antibody to the intracellular protein myosin and creatine kinase release were used to determine membrane integrity and discriminate between viable and nonviable myocardial tissue. The uptake of radiolabeled antimyosin antibody and release of creatine kinase after reperfusion were increased in heparin-pretreated hearts exposed to heparinase, indicating a loss of membrane integrity and increased myocyte injury. These results demonstrate that neutralization of heparin by heparinase promotes increased myocardial injury after reperfusion of the ischemic myocardium.     

葛根素预处理对离体大鼠心肌缺血再灌注损伤的保护作用

目的通过建立大鼠离体心脏缺血再灌注模型,探讨葛根素预处理对大鼠心肌缺血再灌注损伤的保护作用及其可能机制。方法在langendǒrff离体心脏体外灌注模型复制基础上,采用随机对照方法将50只雄性SD大鼠平均分为5组:对照组、缺血再灌注组、缺血预处理组、小剂量葛根素预处理组、大剂量葛根素预处理组,记录每只大鼠平衡灌注15 min、再灌注153、0 min的心功能变化,包括心率(HR)、左室最高压(LVSP)、左室舒张末压(LVEDP)、左室压力升高速率(+dp/dtmax)、左室压力降低速率(-dp/dtmax)。并于平衡灌注15 min、复灌1、3、5、10、15、30 min测定冠脉流出液中肌酸激酶(CK)的含量。测定心肌丙二醛(MDA)、超氧化物歧化酶(SOD)、一氧化氮(NO)的含量,并作电镜检查。结果缺血再灌注组可引起HR、LVSP、+dp/dtmax、-dp/dtmax下降,LVEDP升高以及CK释放增加,心肌MDA产生增多、SOD及NO含量降低,与对照组相比有显著性差异。缺血预处理组及葛根素预处理组均能显著改善缺血再灌注引起的心功能损伤,降低CK的释放,减少心肌组织MDA的生成,并增加心肌组织中SOD和NO含量,减轻心肌细胞超微结构的病理改变。大剂量葛根素预处理组比小剂量葛根素预处理组对上述指标的改善更为显著。结论葛根素预处理能减少脂质过氧化,明显改善心功能,提高心肌组织对后续缺血的耐受性。这种保护作用存在量效关系,其产生与心肌中SOD增高减轻了氧自由基损伤和NO增高扩张冠脉有关。     

内皮祖细胞与缺血性脑血管疾病的治疗

背景：近年来大量基础研究发现,在成年机体的骨髓及外周血中均能找到内皮祖细胞,其在成体病理条件下对血管再生与新生过程起着重要作用。脑梗死发生后,在缺血部位存在着新血管形成,而此过程同样存在着内皮祖细胞的参与,内皮祖细胞的增加以及最大程度参与到新血管组织中,这些很可能是脑血管疾病治疗的一条重要途径。目的：以文献资料分析法探讨分析内皮祖细胞的特性和作用,及其在缺血性脑血管疾病中的应用进展。方法：检索SCI数据库、CNKI数据库2002至2011年有关内皮祖细胞与缺血性脑血管疾病治疗的相关文献,检索词为＂内皮祖细胞（endothelial progenitor cells,EPCs）;前体细胞（precursor cell）;脑卒中（stroke）;脑缺血（brain ischemia,cerebral ischemia）;脑梗死（cerebral infarction,CI）;缺血性脑血管病（ischemic cerebral vascuIar disease）＂,以文字和图表形式进行结果的统计和计量分析,描述其分布特征。结果与结论：内皮祖细胞是成年个体骨髓中的前体细胞,能迁移至外周血并分化为成熟血管内皮细胞,具有良好的增殖潜能,并参与血管内皮修复、缺血器官的新血管形成。根据内皮祖细胞的生物特性与作用,目前国内外研究发现内皮祖细胞能防治脑动脉粥样硬化,参与脑缺血后血管再生,预测评估脑缺血病情,以及对脑出血后具有一定的治疗作用。因此,内皮祖细胞在缺血性脑血管疾病治疗中展现出广泛的应用前景。     

心肌缺血日负荷对新西兰兔血管内皮生长因子表达的影响

要目的:观察心肌缺血日负荷对新西兰兔血管内皮生长因子(VEGF)表达的影响。方法:健康成年新西兰兔38只,体重2.0—2.5kg。根据日缺血次数随机分为2次/日组、4次/日组、6次/日组、假手术组以及正常组。将气囊梗阻器安装在冠状动脉左室支,制作间断性心肌缺血模型。缺血负荷为2min/h,缺血刺激4周。取缺血区心肌观察形态学变化;WesternBlotting方法检测VEGF蛋白在缺血区心肌的表达水平;取兔术前和缺血刺激前、后24h血清检测肌钙蛋白(cTnI)。结果:气囊充气可以有效、迅速地诱发心肌缺血;与假手术组和正常组相比,缺血刺激2次/日组、4次/日组、6次/日组缺血心肌VEGF表达升高(P<0.05),各缺血刺激组间的VEGF表达无差异;各组左室支支配区未见心肌坏死和血栓形成;兔缺血刺激后24h血清肌钙蛋白无明显升高。结论:持续4周的间断性心肌缺血对心肌无损伤,可以显著提高缺血区心肌VEGF表达增加,不同刺激频率对其表达无明显影响。     

骨髓干细胞动员对心肌梗死大鼠心功能的影响

目的 探讨应用粒细胞集落刺激因子(G—CSF)动员大鼠自体骨髓干细胞治疗心肌梗死对心功能的影响及其可能机制。方法 用异丙肾上腺素(ISO)制作大鼠心肌梗死模型，用骨髓干细胞动员剂G—CSF动员自体骨髓干细胞释放和迁移至心肌梗死灶，于用ISO后24、48h杀死大鼠，取出心脏；用ISO后4周，先用NPA—V多导生理仪检测大鼠血流动力学、心功能指标，随后杀死大鼠，取出心脏，通过免疫组化、HE染色和VG染色方法观察大鼠心梗灶的CD34^ 细胞的浸润及心肌再生、心肌纤维化的情况。结果 用ISO后4周，G—CSF动员组大鼠血流动力学指标、心功能参数均比对照组改善。用ISO后24h，动员组大鼠心梗区可见CD34^ 细胞浸润，并有CD34^ 阳性的新生心肌细胞生长，4周后瘢痕组织少，心肌纤维化程度轻，心肌基本结构得到保护。结论 急性心梗发生后，应用G—CSF动员自体骨髓干细胞向心梗灶内迁移、存活和向心肌细胞、血管内皮细胞等分化；并通过心肌再生、抑制缺血心肌纤维化和保护缺血心肌基本结构而改善心功能。     

Influence of methylprednisolone of the sequential redistribution of cathepsin D and other lysosomal enzymes during myocardial ischemia in rabbits.

Occlusion of the circumflex coronary artery induced a profound redistribution in ischemic rabbit myocardium of several lysosomal acid hydrolases, including cathepsin D, B-acetylglycosaminidase, and acid phosphatase. 30-45 min after ligation non-sedimentable cathepsin D activity rose from 36% of the total activity to 42-48%, and in immunohistochemical preparations cathepsin D appeared to have diffused from lysosomes into the cytosol of injured cells. A pharmacologic dose of methylprednisolone (50mg/kg) significantly delayed the subcellular redistribution of cathepsin D and the other hydrolases in ischemic heart. Thus, in treated hearts the nonsedimentable activity of cathepsin D rose to only 38% after 30 min of ischemia and 42% after 45 min (P is less than 0.05 compared to untreated ischemia at each time). Similarly, unlike untreated hearts, noevidence of enzyme diffusion from lysosomes could be demonstrated immunohistochemically in corticosteroid-treated ischemic hearts for over 45 min. After 1-2 h of ischemia, however, steroid-protected myocytes deteriorated and the biochemical activity and anatomical distribution of cathepsin D were indistinguishable from untreated ischemic hearts. This study demonstrates that corticosteroid pretreatment does not prevent alterations in cardiac lysosomes during severe ischemia indefinitely, but does delay their development significantly.     

Cardioprotective Effects of Red Blood Cells on Ischemia and Reperfusion Injury in Isolated Rat Heart: Release of Nitric Oxide as a Potential Mechanism

BACKGROUND: Circulating cells influence myocardial function during ischemia and reperfusion, (eg, neutrophils exacerbate, and platelets protect the myocardium from deterioration). This study was designed to determine the role of red blood cells on myocardial function following ischemia and reperfusion in isolated rat hearts. METHODS AND RESULTS: Exposure of buffer-perfused hearts to 40 minutes of total ischemia followed by 30 minutes of reperfusion resulted in myocardial dysfunction and injury, indicated by decrease in the force of cardiac contraction (FCC, -25 +/- 4%), increase in the coronary perfusion pressure (CPP, +20 +/- 3%) and decrease in myocardial superoxide dismutase (SOD, 2.5 +/- 0.2 vs 3.5 +/- 0.4 U/mg protein in sham ischemic hearts, P <.05). Perfusion of the hearts with washed rat red blood cells showed significant protective effects against ischemia and reperfusion, indicated by minimal change in FCC (-10 +/- 4%) and CPP (+3 +/- 3%) (both P <.01 vs buffer alone perfused hearts) and preservation of myocardial SOD activity (2.8 +/- 0.4 U/mg protein, P <.05 vs buffer alone perfused hearts). The cardioprotective effects of red blood cells were attenuated when the red blood cells were preincubated with the nitric oxide blood cells were attenuated when the red blood cells were preincubated with the nitric oxide blood cells were attenuated when the red blood cells were preincubated with the nitric oxide synthase inhibitors N(omicron)-nitro-l-arginine (l-NNA, 5 x 10(-4)M) or N(omicron)-nitro-l-arginine methyl ester (l-NAME, 5 x 10(-4)M) at 37 degrees C for 60 minutes before perfusion of the heart. Perfusion of hearts with the nitric oxide precursor l-arginine (2 x 10(-4)M) also exerted significant protective effects on FCC ( - 14 +/- 4%), CPP (+12 +/- 3%) and myocardial SOD activity (2.9 +/- 0.2 U/mg protein) following ischemia and reperfusion. In other studies, washed rat red blood cells expressed nitric oxide synthetase activity which was inhibited by both l-NNA and l-NAME. CONCLUSIONS: These results suggest that red blood cells exert cardioprotective effects against ischemia and reperfusion at least in part by the l-arginine-nitric oxide pathway in isolated rat hearts.     

围术期心血管危险因素对骨髓祖细胞的影响简

背景：移植自体骨髓干细胞治疗缺血性心脏病已进行了10余年的临床试验,但试验结果在不同的患者中存在差异。因此,有必要鉴定哪些心血管病患者的危险因素影响骨髓干细胞的水平和功能。目的：观察冠心病患者围术期危险因素对骨髓祖细胞数量及功能的影响。方法：选择44例拟行冠状动脉旁路移植的冠心病患者,采集实验室和临床资料;术中经胸骨穿刺采集骨髓,应用 Ficol 淋巴细胞分离液密度梯度离心法分离骨髓单个核细胞,计数并应用锥虫蓝拒染法检测其活性;应用流式细胞仪分析检测CD34＋、CD133＋和CD34＋CD133＋细胞的水平;应用集落形成试验和细胞迁移试验评价骨髓祖细胞功能。结果与结论：术中经胸骨抽取20 mL骨髓可获得（10-89）×106个骨髓单个核细胞,活性在95%以上,等量的骨髓血获得的骨髓单个核细胞的量与患者年龄之间存在明显负相关关系（n=44,r=-0.788,P=0.001）;流式细胞仪检测 CD34＋细胞占（0.94±0.39）%,CD133＋细胞占（0.46±0.28）%,CD34＋CD133＋细胞占（0.53±0.26）%;糖尿病患者骨髓 CD34＋和 CD133＋细胞水平明显低于非糖尿病患者;高龄、女性和心功能较差与骨髓祖细胞集落形成能力降低有关;CD34＋细胞水平与骨髓单个核细胞的迁移能力存在明显的正相关。结果表明经胸骨应用密度梯度离心法可获得足够数量的骨髓单个核细胞作为缺血性心脏病治疗的供体细胞,年龄、性别、糖尿病、心功能与骨髓单个核细胞数量和功能有关。