骨髓动员对大鼠骨髓源内皮祖细胞功能的影响

目的观察大鼠骨髓动员后骨髓源内皮祖细胞(endothelial progenitor cells,EPCs)功能的改变,探讨骨髓动员后骨髓干细胞移植提高下肢缺血性疾病疗效的可能机制。方法按是否接受重组人粒细胞集落刺激因子(recombinant human granulocyte-macrophage colony-stimulatory factor,rhG-CSF)注射液注射将Lewis大鼠分为动员组和对照组,获取骨髓单个核细胞用EBM-2培养液进行诱导分化,培养7d后对贴壁细胞进行EPCs的鉴定;采用黏附能力测定实验观察EPCs的黏附能力。另取Lewis大鼠制备单侧后肢缺血模型,在模型制备后7d将8×106个EPCs移植至缺血侧后肢的肌肉内,按照移植EPCs来源不同将后肢缺血大鼠分为动员组和对照组。EPCs移植4周后行后肢血管造影,计算缺血侧后肢侧支血管数目。结果大鼠骨髓单个核细胞培养7d后黏附能力测定实验中动员组黏附EPCs数量为(22.3±2.8)个/×100高倍视野大于对照组(16.8±4.4)个/×100高倍视野(P<0.05);大鼠骨髓源EPCs移植至缺血肢体后4周动员组EPCs移植后缺血侧后肢侧支血管数目为(4.7±1.0)大于对照组(3.3±0.5)(P<0.05)。结论骨髓动员使骨髓源EPCs功能改善,其可能是骨髓动员后骨髓干细胞移植提高下肢缺血性疾病疗效的机制之一。     

Progenitors in motion: mechanisms of mobilization of endothelial progenitor cells

Endothelial progenitor cells are a population of bone marrow-derived mononuclear cells thought to engage in endothelial repair and hence are considered potential therapeutic agents in many pathological conditions. The mechanism of their exit from the bone marrow to the circulation and damaged tissues, termed mobilization, has not been fully elucidated. Despite this, several pharmacological interventions have been shown to influence mobilization of these specialized cells. Here we review the current understanding of their mobilization.     

改善糖尿病内皮祖细胞功能的研究进展

内皮祖细胞（EPC）为来源于骨髓及外周血中的干细胞,能定向增殖分化为内皮细胞,参与血管损伤后的修复。研究显示,改善糖尿病EPC功能,可以预防和降低糖尿病并发症的发生。追踪近年来改善EPC功能的研究进展,就其对糖尿病并发症的预防和改善作用做一综述,以期为糖尿病的治疗提供新思路。     

Dipeptidyl peptidase-4 inhibitor improves neovascularization by increasing circulating endothelial progenitor cells

BACKGROUND AND PURPOSE

Current methods used to treat critical limb ischaemia (CLI) are hampered by a lack of effective strategies, therefore, therapeutic vasculogenesis may open up a new field for the treatment of CLI. In this study we investigated the ability of the DPP-4 inhibitor, sitagliptin, originally used as a hypoglycaemic agent, to induce vasculogenesis in vivo.

EXPERIMENTAL APPROACH

Sitagliptin were administered daily to C57CL/B6 mice and eGFP transgenic mouse bone marrow-transplanted ICR mice that had undergone hindlimb ischaemic surgery. Laser Doppler imaging and flow cytometry were used to evaluate the degree of neovasculogenesis and circulating levels of endothelial progenitor cells (EPCs) respectively. Cell surface markers of EPCs and endothelial NOS (eNOS) in vessels were studied.

KEY RESULTS

Sitagliptin elevated plasma glucagon-like peptide-1 (GLP-1) levels in mice subjected to ischaemia, decreased plasma dipeptidyl peptidase-4 (DPP-4) concentration, and augmented ischaemia-induced increases in stromal cell-derived factor-1 (SDF-1) in a dose-dependent manner. Blood flow in the ischaemic limb was significantly improved in mice treated with sitagliptin. Circulating levels of EPCs were also increased after sitagliptin treatment. Sitagliptin also enhanced the expression of CD 34 and eNOS in ischaemic muscle. In addition, sitagliptin promoted EPC mobilization and homing to ischaemic tissue in eGFP transgenic mouse bone marrow-transplanted ICR mice.

CONCLUSION AND IMPLICATIONS

Circulating EPC levels and neovasculogenesis were augmented by the DPP-4 inhibitor, sitagliptin and this effect was dependent on an eNOS-related pathway in a mouse model of hindlimb ischaemia. The results indicate that oral administration of sitagliptin has therapeutic potential as an inducer of vasculogenesis.     

普伐他汀对人内皮祖细胞一氧化氮合成的影响

目的观察普伐他汀对人内皮祖细胞（EPCs）一氧化氮（NO）合成的影响。方法密度梯度离心法获取外周血单个核细胞,培养7d后,收集贴壁细胞并分别加入普伐他汀,10μmol/L及100μmol/L干预48h,免疫组化、荧光显微镜和流式细胞仪鉴定EPC,用RT-PCR方法测定对细胞内皮型一氧化氮合酶（eNOS）mRNA表达的影响,并用硝酸还原酶法测定培养液中一氧化氮（NO）的水平。结果普伐他汀组的人内皮祖细胞eNOS mRNA的表达、NO的合成明显增加。结论普伐他汀可增加人内皮祖细胞eNOS mRNA的表达和NO的合成     

Human malignant glioma cells expressing functional formylpeptide receptor recruit endothelial progenitor cells for neovascularization

Endothelial progenitor cells (EPCs) are involved in tumor neovascularization with undefined mechanisms. In this study, we explored the role of formylpeptide receptor, a G protein-coupled receptor, expressed by human malignant glioma cells in neovascularization of malignant glioma. EPCs were isolated from human umbilical cord blood and their migratory capability and tubulogenesis induced by the supernatant of U87 glioblastoma (GBM) cell line were examined. We also assessed the recruitment and incorporation of EPCs into orthotopic intracranial tumors formed by implanted U87 GBM cells. The supernatant of control U87 cells induced high levels of migration and tubule-formation in vitro by EPCs. In contrast, the chemotactic and tubule-stimulating activities on EPCs in the supernatant of U87 cells with FPR knocking down by small interference (si) RNA were significantly attenuated. In addition, the number of EPCs recruited and incorporated into intracranial glioma xenografts was significantly higher in tumors formed by control U87 cells than tumors formed by U87 cells containing FPR-siRNA. Our results suggest that expression of functional FPR in glioma cells plays an important role in regulating vasculogenesis by EPCs, which constitute a novel target for anti-angiogenic therapy in gliomas.     

阿托伐他汀对慢性肾衰竭大鼠外周血内皮祖细胞的影响

目的探讨阿托伐他汀对慢性肾衰竭大鼠外周血内皮祖细胞(endothelial progenitor cells,EPCs)数量和功能的影响。方法采用分阶段5/6肾切除制备大鼠慢性肾衰竭模型。实验动物随机分为4组:假手术组、慢性肾衰竭组(模型组)、8mg.kg-1.d-1阿托伐他汀干预组(小剂量组)、16mg.kg-1.d-1阿托伐他汀干预组(大剂量组)。大鼠阿托伐他汀灌胃8周后,取其外周血分离与培养EPCs,并检测EPCs数量及其增殖、黏附能力。结果与假手术组比较,慢性肾衰竭大鼠外周血EPCs数量及其增殖、黏附能力均下降(P<0.05)。应用阿托伐他汀能明显增加慢性肾衰竭大鼠外周血EPCs数量,改善外周血EPCs增殖、黏附能力(P<0.05),并且呈剂量依赖性。结论阿托伐他汀可改善慢性肾衰竭大鼠外周血EPCs的数量和功能。     

Effects of electroacupuncture on endothelial function and circulating endothelial progenitor cells in patients with cerebral infarction

This study evaluated the effects of electroacupuncture (EA) on endothelial function and endothelial progenitor cells (EPC) in patients with cerebral infarction. In a randomized, placebo‐controlled, crossover study, 20 patients with cerebral infarction were randomized into two treatment groups: EA or placebo. Before and after each intervention, pulse amplitude tonometry (PAT) was used to assess endothelial function and peripheral blood was analyzed for the number of EPCs. Circulating EPCs were quantified by flow cytometry as CD45^lowCD34⁺KDR2⁺ cells. Plasma vascular endothelial growth factor (VEGF) and interleukin (IL)‐10 levels were measured. Seven days later, crossover was performed on each group, with each group receiving the other treatment using the same protocol. The PAT hyperemia ratio ranged from 1.57 ± 0.41 to 2.04 ± 0.51 after EA, representing a significant improvement (P = 0.002); however, there was no improvement in the placebo group (P = 0.48). Circulating EPCs, as measured by flow cytometry, increased to 110.6 ± 74.3/100 μL in the EA group (P = 0.001) but did not change in the placebo group (45.9 ± 35.3/100 μL, P = 0.08). The increases in the number of EPCs and the PAT ratio after treatment were correlated (r = 0.78, P < 0.001). Plasma VEGF levels increased with EA compared to baseline (261.2 ± 34.0 vs 334.9 ± 80.5 pg/mL, P = 0.003). The number of circulating EPCs was positively correlated with plasma levels of VEGF (r = 0.50, P = 0.02). In conclusion, EA induced improvement of EPC levels and the PAT ratio in patients with cerebral infarction.     

糖尿病患者血管内皮祖细胞研究进展

血管内皮祖细胞(EPC)来源于骨髓,是具有修复内皮和新生血管功能的干细胞。糖尿病患者外周血EPC数量和功能均出现下降,EPC已成为糖尿病及其并发症治疗的一个新靶点。本文综述EPC在糖尿病病理生理中的作用和药物干预机理的研究进展。     

内皮祖细胞的鉴定及培养方法

近10年来,内皮祖细胞(endothelial progenitor cells,EPCs)的研究受到越来越多的关注。研究发现,循环血液中EPCs储量的改变伴随着心血管疾病的不同表现。因此,EPCs作为心血管疾病的生物标志物及修复受损血管的一种细胞疗法被广泛研究。该文对1997年至今大多数研究中EPCs的鉴定及培养方法做了简要综述。     

洛伐他汀保护内皮祖细胞的机制研究

目的探讨洛伐他汀(lovastatin)保护内皮祖细胞(en-dothelial progenitor cells,EPCs)的机制。方法EPCs与洛伐他汀或者血凝素样氧化型低密度脂蛋白受体(lectin-like oxi-dized low density lipoprotein receptor,LOX-1)的特异性阻断抗体(LOX-1 mAb)预处理24 h后,再与氧化型低密度脂蛋白(oxidized low density lipoprotein,oxLDL)孵育48 h。然后,检测EPCs迁移、粘附和管状结构形成能力。为探讨洛伐他汀的作用机制,检测EPCs生成一氧化氮(nitric oxide,NO)的量,内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)和LOX-1蛋白及mRNA表达。结果oxLDL抑制EPCs迁移、粘附及管状结构形成能力,降低NO产生、eNOS蛋白及mRNA表达,增加LOX-1蛋白及mRNA表达。洛伐他汀和LOX-1 mAb恢复EPCs功能,逆转oxLDL对NO、eNOS及LOX-1的调节。结论洛伐他汀通过调节eNOS和LOX-1而保护EPCs免受oxLDL的损害。     

Resveratrol reduces endothelial progenitor cells senescence through augmentation of telomerase activity by Akt-dependent mechanisms

Background and purpose:

Recent studies have shown that resveratrol increased endothelial progenitor cells (EPCs) numbers and functional activity. However, the mechanisms remain to be determined. Previous studies have demonstrated that increased EPC numbers and activity were associated with the inhibition of EPC senescence, which involves activation of telomerase. Therefore, we investigated whether resveratrol inhibits the onset of EPC senescence through telomerase activation, leading to potentiation of cellular activity.

Experimental approach:

After prolonged in vitro cultivation, EPCs were incubated with or without resveratrol. The senescence of EPCs were determined by acidic β-galactosidase staining. The bromo-deoxyuridine incorporation assay or a modified Boyden chamber assay were employed to assess proliferative or migratory capacity, respectively. To further examine the underlying mechanisms of these effects, we measured telomerase activity and the phosphorylation of Akt by western blotting.

Key results:

Resveratrol dose dependently prevented the onset of EPCs senescence and increased the proliferation and migration of EPCs. The effect of resveratrol on senescence could not be abolished by eNOS inhibitor or by an oestrogenic receptor antagonist. Resveratrol significantly increased telomerase activity and Akt phosphorylation. Pre-treatment with the PI3K inhibitor, {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002, significantly attenuated resveratrol-induced telomerase activity.

Conclusions and implications:

Resveratrol delayed the onset of EPC senescence and this effect was accompanied by activation of telomerase through the PI3K-Akt signalling pathway. The inhibition of EPCs senescence by resveratrol might protect EPCs against dysfunction induced by pathological factors in vivo and improve EPC functional activities in a way that may be important for cell therapy.     

Effects of resveratrol on number and activity of endothelial progenitor cells from human peripheral blood

1. It has been well established that oestrogens can increase the number of endothelial progenitor cells (EPC) by anti-apoptotic effects. Resveratrol, a polyphenolic phytoalexin extracted from grapes and wine, has been reported to act as an oestrogen receptor agonist. We hypothesize that putative phyto-oestrogen may promote EPC proliferation and survival in vitro. 2. Endothelial progenitor cells were isolated from human peripheral blood and identified immunocytochemically. Endothelial progenitor cells were incubated with resveratrol (1, 10, 25 and 50 mmol/L) or control for specified times. Cell proliferation, migration and in vitro vasculogenesis were assayed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetra-zolium bromide (MTT) assay, modified Boyden chamber assay and in vitro vasculogenesis detection, respectively. 3. Resveratrol increased the number of EPC and promoted EPC proliferation, adhesion and migration in a dose- and time-dependent manner. Cell number peaked at 50 mmol/L resveratrol after incubation for 24 h compared with vehicle control (61.3 +/- 5.8 vs 112.8 +/- 7.2, respectively; P < 0.01). 4. Furthermore, cell cycle analysis showed that 50 mmol/L resveratrol significantly increased the S phase and decreased the G(0)/G(1) phase of EPC. In addition, resveratrol increased vascular endothelial growth factor production and further induced vasculogenesis in vitro. 5. In conclusion, resveratrol significantly induces EPC proliferation, migration and further promotes angiogenesis in vitro.     

Implantation of bFGF-treated islet progenitor cells ameliorates streptozotocin-induced diabetes in rats

Aim:

To examine whether implantation of islet preparation-derived proliferating islet cells (PIC) could ameliorate diabetes in rats.

Methods:

PIC were expanded from rat islet preparation by supplementation of basic fibroblast growth factor (bFGF) and implanted into rats with streptozotocin (STZ)-induced diabetes through the portal vein. Body weight and blood glucose levels were measured. Serum insulin levels were measured by radioimmunoassay. The presence of insulin-positive cells was determined by hematoxylin and immunohistochemical staining.

Results:

Cultured islet cells (CIC) were demonstrated to dedifferentiate in vitro, and the apoptosis ratios reached more than 50% by the 15th day post-isolation. PIC cells treated with bFGF (20 ng/mL) continued growing within 30 days after isolation, and no apoptotic cells were detected. Implantation of PIC into diabetic rats was capable of ameliorating diabetes, in terms of the restoration of euglycemia, weight gain, improved glucose response and elevated serum insulin levels for up to 130 days. Livers derived from PIC-implanted rats were examined for insulin expression and single insulin-positive cells. In addition, most islets of PIC-implanted STZ-induced diabetic rats were intact at 130 days post-transplantation and comparable to those of normal rats.

Conclusion:

Implantation of bFGF-treated proliferating islet cells is a promising cellular therapeutic approach for diabetes.     

The effect of acute exposure to coarse particulate matter air pollution in a rural location on circulating endothelial progenitor cells: results from a randomized controlled study

Abstract

Context: Fine particulate matter (PM) air pollution has been associated with alterations in circulating endothelial progenitor cell (EPC) levels, which may be one mechanism whereby exposures promote cardiovascular diseases. However, the impact of coarse PM on EPCs is unknown.

Objective: We aimed to determine the effect of acute exposure to coarse concentrated ambient particles (CAP) on circulating EPC levels.

Methods: Thirty-two adults (25.9?±?6.6 years) were exposed to coarse CAP (76.2?±?51.5?μg?m^?3) in a rural location and filtered air (FA) for 2 h in a randomized double-blind crossover study. Peripheral venous blood was collected 2 and 20 h post-exposures for circulating EPC (n?=?21), white blood cell (n?=?24) and vascular endothelial growth factor (VEGF) (n?=?16–19) levels. The changes between exposures were compared by matched Wilcoxon signed-rank tests.

Results: Circulating EPC levels were elevated 2 [108.29 (6.24–249.71) EPC?mL^?1; median (25th–75th percentiles), p?=?0.052] and 20 h [106.86 (52.91–278.35) EPC?mL^?1, p?=?0.008] post-CAP exposure compared to the same time points following FA [38.47 (0.00–84.83) and 50.16 (0.00–104.79) EPC?mL^?1]. VEGF and white blood cell (WBC) levels did not differ between exposures.

Conclusions: Brief inhalation of coarse PM from a rural location elicited an increase in EPCs that persisted for at least 20 h. The underlying mechanism responsible may reflect a systemic reaction to an acute “endothelial injury” and/or a circulating EPC response to sympathetic nervous system activation.     

中药保护内皮祖细胞的有效成分及作用机制

近5年来中药界学人发现22种中药成分可有效保护内皮祖细胞（EPCs）。分别通过调节氧化应激反应、抑制EPCs凋亡、阻遏炎症因子的分泌、增强EPC动员、迁移、分化等生物学功能发挥对EPCs的保护作用。对此做系统论述及整理,并总结目前研究中存在的问题及以后的研究方向。