Significance and therapeutic potential of endothelial progenitor cell transplantation in a cirrhotic liver rat model

BACKGROUND & AIMS: We investigated whether endothelial progenitor cell (EPC) transplantation could reduce established liver fibrosis and promote hepatic regeneration by isolating rat EPCs from bone marrow cells. METHODS: Recipient rats were injected intraperitoneally with carbon tetrachloride (CCl(4)) twice weekly for 6 weeks before initial administration of EPCs. CCl(4) was then readministered twice weekly for 4 more weeks, and EPC transplantation was carried out for these same 4 weeks. RESULTS: At 7 days in culture, the cells expressed Thy-1, CD31, CD133, Flt-1, Flk-1, and Tie-2, suggesting an immature endothelial lineage. Immunohistochemical analyses showed fluorescent-labeled, transplantation EPCs were incorporated into the portal tracts and fibrous septa. Single and multiple EPC transplantation rats had reduced liver fibrosis, with decreased alpha2-(I)-procollagen, fibronectin, transforming growth factor-beta, and alpha-smooth muscle actin-positive cells. Film in situ zymographic analysis revealed strong gelatinolytic activity in the periportal area, in accordance with EPC location. Real-time polymerase chain reaction analysis of multiple EPC-transplantation livers showed significantly increased messenger RNA levels of matrix metalloproteinase (MMP)-2, -9 and -13, whereas tissue inhibitor of metalloproteinase-1 expression was significantly reduced. Expression of hepatocyte growth factor, transforming growth factor-alpha, epidermal growth factor, and vascular endothelial growth factor was increased in multiple EPC-transplantation livers, while hepatocyte proliferation increased. Transaminase, total bilirubin, total protein, and albumin levels were maintained in EPC-transplantation rats, significantly improving survival rates. CONCLUSIONS: We conclude that single or repeated EPC transplantation halts established liver fibrosis in rats by suppressing activated hepatic stellate cells, increasing matrix metalloproteinase activity, and regulating hepatocyte proliferation.     

Early breast cancer therapy and cardiovascular injury

Although recent advances in curative-intent therapies are beginning to produce significant survival gains in early breast cancer, these improvements may ultimately be attenuated by increased risk of long-term cardiovascular mortality. This paper reviews emerging evidence on the cardiovascular effects of breast cancer adjuvant therapy and proposes a new entity that we have labeled the "multiple-hit" hypothesis. The evidence that lifestyle modification, especially exercise therapy, may mitigate these adverse effects is also reviewed. These issues are of considerable practical importance for cardiovascular clinicians, as identification and intervention in those at high risk for cardiovascular complications may reduce a major cause of mortality in women with early breast cancer.     

自体骨髓单个核细胞移植治疗大鼠后肢缺血

目的　探讨自体骨髓单个核细胞（BM-MNC）移植用于大鼠缺血后肢的治疗后实现血管再生的能力。方法　建立大鼠后肢缺血动物模型,将取于自体的BM-MNC制成细胞悬液注射于缺血部位,分别在移植后2和30d时行动脉造影,用免疫组化方法检测内皮祖细胞（EPC）,毛细血管密度以及测定血管内皮生长因子(VEGF)的表达。结果　缺血肌组织中的EPC含量增高（P<0.01）。BM-MNC移植组在移植早期VEGF表达显著增高（P<0.01）。细胞移植后30dBM-MNC移植组毛细血管密度明显高于其他组（P<0.01）,血管造影可见侧支循环建立。结论　自体骨髓单个核细胞移植于大鼠后肢缺血区能促进血管新生,改善侧支循环,可望成为一种简单有效的治疗下肢缺血的方法。     

内皮祖细胞移植对糖尿病兔下肢缺血区血管生成相关基因表达的影响

目的研究内皮祖细胞（EPC）移植治疗糖尿病兔下肢缺血对血管生成相关基因表达的影响。方法日本大耳白兔16只，四氧嘧啶法建立糖尿病模型后，随机分为磷酸盐缓冲液（PBS）对照组与EPC治疗组，分别用PBS和骨髓来源经体外扩增的EPC移植于下肢缺血区，14天后用基因芯片分析EPC移植对血管生成相关基因表达的影响，同时检测肌浆中血管内皮生长因子（VEGF）浓度。结果EPC治疗组下肢缺血区27个血管生成基因表达上调超过2倍，移植治疗组VEGF的浓度显著高于对照组，差异有统计学意义。结论EPC植入糖尿病兔下肢缺血区，可以上调包括VEGF在内的多种血管生成相关基因，同时肌浆中VEGF水平升高。     

Circulating endothelial progenitor cells correlate with erectile function in patients with coronary heart disease.

AIMS: The aim of the study was to determine the influence of endothelial progenitor cells (EPC) on erectile dysfunction (ED). EPC play a major role in repair mechanisms of the endothelial monolayer, but the role of EPC in ED is unclear. METHODS AND RESULTS: Circulating levels of CD34(+)/KDR(+) and CD133(+) EPC were determined in 119 patients with known coronary artery disease. ED was evaluated with an ED-score generated from the KEED questionnaire. Prevalence of ED was 59.7%. In univariate analysis, age, hypertension, reduced left ventricular ejection fraction (LVEF), diabetes, and circulating levels of CD133(+) EPC, but not cardiovascular drug treatment were associated with ED. Body mass index (BMI) was positively (r = 0.319, P=0.003) and high-density lipoprotein was negatively (r=-0.246, P=0.034) correlated with ED. Adjustment for age, diabetes, hypertension, BMI, smoking, LVEF, use of statins and lower urinary tract symptoms, and prior coronary intervention revealed low levels of circulating immature CD133(+) EPC as independent risk factor for ED (95% CI -11.183 to -1.7371, P=0.008). CONCLUSION: Reduced levels of circulating CD133(+) EPC are an independent risk factor for ED. Thus, EPC may be a link between cardiovascular risk factors, endothelial dysfunction, and ED.     

Effects of 20,25-diazacholesterol treatment on the decay of end-plate currents

The open time of the acetylcholine-activated end-plate channel (τ) was estimated as the time constant of end-plate current decay in magnesium-depressed nervemuscle preparations. Pretreatment of rats with 20,25-diazacholesterol, which is known to lower membrane concentrations of cholesterol, significantly decreased τ. Thus the membrane milieu of the channel influences the functional properties of the cholinergic receptor.     

Low-molecular-weight fucoidan enhances the proangiogenic phenotype of endothelial progenitor cells

Endothelial progenitor cell (EPC) transplantation is a potential means of inducing neovascularization in vivo. However, the number of circulating EPC is relatively small, it may thus be necessary to enhance their proangiogenic properties ex vivo prior to injection in vivo. Fucoidan has previously been shown to potentiate in vitro tube formation by mature endothelial cells in the presence of basic fibroblast growth factor (FGF-2). We therefore examined whether fucoidan, alone or combined with FGF-2, could increase EPC proangiogenic potency in vitro. EPC exposure to 10 microg/ml fucoidan induced a proangiogenic phenotype, including cell proliferation (p < 0.01) and migration (p < 0.01); moreover, differentiation into vascular cords occurred in the presence of FGF-2 (p < 0.01). This latter effect correlated with upregulation of the cell-surface #alpha6 integrin subunit of the laminin receptor (p < 0.05). Compared to untreated HUVEC, untreated EPC #alpha6 expression and adhesion to laminin were enhanced two-fold. Fucoidan treatment further enhanced HUVEC but not EPC adhesion to laminin. These results show that fucoidan enhances the proangiogenic properties of EPC and suggest that ex vivo fucoidan preconditioning of EPC might lead to increased neovascularization when injected into ischemic tissues.     

Signaling of endothelial cytoprotection in transplantation

A better knowledge of the processes by which endothelium can resist to cell death and adapt to injury by specific intracellular signaling pathways and dedicated protein regulation is a key step to understand how vascular inflammation/injury develops and how it is regulated. This review focuses on signaling pathways and molecular effectors that trigger the balance between endothelial cell activation and dysfunction. In addition to the canonical nuclear factor-κB (NF-κB), phosphatidyl inositol 3-kinase (PI-3K) and mitogen-activated protein kinases (MAPK) that orchestrated the inflammatory response and its termination we report here additive pathways such as Notch pathway and protein C/protease activated receptor (PAR) pathway that have been also reported to play a role in the control of EC activation and apoptosis. This review also provides an update of the characteristics of some established and novel protective molecules for the endothelium, identified in transplantation.