Endothelialization and Flow Conditioning of Fibrin-Based Media-Equivalents

It is generally accepted that endothelialization and subsequent development of a functional endothelium are of paramount importance to the success of any bioartificial artery. In this study, we aimed to assess the ability of smooth muscle cell-remodeled, fibrin-based media-equivalents (MEs) to be endothelialized, examine the morphological changes of endothelial cells (ECs) associated with exposure to physiologically-relevant shear stress in a custom-built bioreactor, and determine if adherent ECs are capable of withstanding average physiological shear stresses. It was found that MEs could be readily endothelialized with surface coverages of 98.8 ± 0.9% after two days, and the ECs expressed von Willebrand factor. Furthermore, EC retention remained high (steady: 96.5 ± 4.4%, pulsatile: 94.3 ± 4.3%) under exposure to physiologically relevant shear stresses for 48 h. The results indicate that these MEs are conducive to generating an EC monolayer, with the ECs possessing adhesion strength sufficient to withstand physiological shear stress and maintain a normal phenotype.     

The effects of antimycin A on endothelial cells in cell death,reactive oxygen species and GSH levels

Antimycin A (AMA) inhibits mitochondrial electron transport chain between cytochrome b and c. Here, we evaluated the effects of AMA on the growth and death of endothelial cells (ECs) in relation to reactive oxygen species (ROS) and glutathione (GSH) levels. AMA inhibited the growth of calf pulmonary artery endothelial cells (CPAEC) and human umbilical vein endothelial cells (HUVEC). AMA also induced apoptosis in both ECs which was accompanied by the loss of mitochondrial membrane potential (MMP; ΔΨ_m). HUVEC were more sensitive to AMA than CPAEC. AMA increased ROS level in CPAEC but decreased the levels in HUVEC. Z-VAD (pan-caspase inhibitor) mildly prevented apoptosis in AMA-treated ECs without the significant changes of ROS. N-acetyl-cysteine (NAC; a well-known antioxidant) decreased ROS levels in AMA-treated ECs. NAC reduced CPAEC death by AMA but enhanced HUVEC death by it. Furthermore, AMA increased GSH depleted cell numbers in ECs. Buthionine sulfoximine (BSO; an inhibitor of GSH synthesis), showing a pro-apoptotic effect on AMA-treated HUVEC, significantly increased GSH depleted cell number but it did not affect cell death and GSH depletion in AMA-treated CPAEC. In conclusion, AMA inhibited the growth of ECs via caspase-dependent apoptosis. ROS level change by AMA was partially related to CPAEC death, but did not affect HUVEC death. The change of GSH contents by AMA influenced the death of ECs.     

蕲蛇酶联合肝素治疗对兔下腔静脉血栓血管内膜的影响研究

目的:研究蕲蛇酶联合肝素治疗对兔下腔静脉血栓血管内膜的影响。方法:复制下腔静脉血栓模型后均分为3组,即肝素、尿激酶联合肝素、蕲蛇酶联合肝素组。复制模型3d后给药,分别在用药后第3、7、10天观察病变血管内膜增生程度、静脉壁胶原纤维沉积量、内皮细胞形态学变化。结果:与肝素组比较,尿激酶联合肝素、蕲蛇酶联合肝素组胶原染色显著减少(P<0.05);在用药后的第3天尿激酶联合肝素、蕲蛇酶联合肝素组内皮细胞损伤程度较轻(P<0.05);第7、10天时,尿激酶联合肝素、蕲蛇酶联合肝素组内皮细胞损伤程度显著减轻(P<0.01)。结论:蕲蛇酶联合肝素在治疗兔下腔静脉血栓方面具有保护病变血管内皮细胞、减轻血管壁炎症反应的功效,对静脉血栓有较好的治疗及预后效果。     

豨莶草提取物对血管内皮NO依赖作用的研究

目的:研究豨莶草提取物对血管内皮NO的依赖作用。方法:采用SD大鼠离体胸主动脉环测定血管张力,观察豨莶草提取物对去氧肾上腺素(PE)诱导的动脉环收缩的影响。结果:豨莶草提取物能抑制PE引起的血管收缩;当用NO合酶抑制剂Nω-硝基-L-精氨酸(L-NNA)预处理血管,在豨莶草提取物低浓度时其舒血管作用明显削弱(P<0.01),在高浓度时则未见明显影响。结论:豨莶草提取物具有内皮NO依赖性舒血管作用。     

西红花酸对晚期糖基化终产物诱导牛血管内皮细胞E-选择素表达的抑制作用

目的：研究西红花酸（crocetin）对晚期糖基化终产物（advanced glycation end products,AGEs）诱导牛主动脉血管内皮细胞（bovine Endothelial cells,BECs）E-选择素（E-selectin）表达的抑制作用。方法：分离纯化新生牛全血的中性粒细胞与单核细胞,用虎红染色法测定西红花酸对牛单核细胞/中性粒细胞与BECs黏附的影响,Cell-based ELISA法和sABC免疫细胞化学法测定E-选择素蛋白表达变化。结果：AGEs（100μg/mL）能促进中性粒细胞和单核细胞对BECs的黏附（P〈0.01 vs control）,用西红花酸（1,0.1,0.01μmol/L）预孵内皮细胞12h后,再用AGEs作用24h,中性粒细胞和单核细胞对BECs的黏附较AGEs模型组降低,且呈剂量依赖性关系（P〈0.05或0.01）。Cell-based ELISA测定结果显示,AGEs作用4h内,BECs中的E-selectin表达水平上升,之后E-selectin表达下降,8h时,恢复接近正常水平。而西红花酸（1,0.1μmol/L）能使E-selectin表达下降。sABC免疫化学结果也证实西红花酸对AGEs诱导BECs中E-selectin表达有抑制作用。结论：西红花酸可通过抑制黏附分子E-selcetin蛋白表达,从而抑制中性粒细胞和单核细胞对内皮细胞的黏附作用,这可能是西红花酸减轻糖尿病血管病变的作用机制之一。     

3类活血化瘀中成药对冠心病稳定型心绞痛血管内皮功能的影响

目的：比较复方丹参滴丸、银杏叶片、维脑路通对冠心病稳定型心绞痛（Chronic Stable Angina）血管内皮功能的影响情况。方法：选取本院稳定型心绞痛患者200例,随机分为服用复方丹参滴丸、银杏叶片、维脑路通及安慰剂4组进行治疗（疗程均为4周）,通过超声方法检测肱动脉血流介导的血管扩张功能（flowmediated dilatation,FMD）、硝酸甘油介导的血管舒张反应（nitrogtycerin—mediated dilation,NMD）,采用酶联免疫吸附法（ELISA）或硝酸还原酶法检测血浆中的内皮素（Endothelin-1,ET-1）及NO水平,分析各组患者服药前后的血管内皮功能变化情况,比较3种活血化瘀类中成药对血管内皮功能的影响。结果：与安慰剂组比较治疗前后的丹参滴丸组和维脑路通组具有较大的FMD值变化（P〈0．05）,治疗前后的丹参滴丸组、维脑路通组和银杏叶组具有较大的NMD值变化（P〈0．05）,治疗前后的丹参滴丸组、银杏叶组和维脑路通组具有较大的ET值变化（P〈0．05）,其中以丹参滴丸组、银杏叶组最大,维脑路通组次之;与安慰剂组、维脑路通组比较,治疗前后的丹参滴丸组具有较大的NO值变化（P〈0．05）;其中以丹参滴丸组最大,银杏叶组、维脑路通组次之。结论：活血化瘀类中成药可改善冠心病稳定型心绞痛患者的血管内皮功能,其作用效果以复方丹参滴丸最为显著,维脑路通及银杏叶片次之。     

Susceptibility of brain microvascular endothelial cells to advanced glycation end products-induced tissue factor upregulation is associated with intracellular reactive oxygen species

There is accumulating evidence that advanced glycation end products (AGEs) are relevant to the formation of vascular complications in diabetes mellitus. The aim of this study was to investigate whether AGEs have a significant effect on tissue factor (TF) expression in brain microvascular endothelial cells compared with that in other arterial endothelial cells. Cultured bovine brain microvascular endothelial cells (BBMECs) and aortic endothelial cells (BAECs) were incubated in medium containing glyceraldehyde-derived AGE (glycer-AGE). TF mRNA expression, protein expression, and activity were measured at multiple time points after glycer-AGE incubation. Participation of reactive oxygen species (ROS) in the effect of glycer-AGE on TF expression was investigated by treatment with a free radical scavenger, edaravone, and intracellular ROS measurements with dihydroethidium (DHE). Basic TF mRNA expression was greater in BBMECs than in BAECs. Glycer-AGE significantly upregulated TF mRNA expression in both cells, and the upregulation was more prominent in BBMECs than in BAECs. TF protein expression and activity were also upregulated with a pattern of being greater in BBMECs than in BAECs. Edaravone significantly attenuated the AGE-induced upregulation of TF mRNA expression, protein expression, and activity. Intracellular ROS levels measured with DHE-stained fluorescent intensity were significantly upregulated by glycer-AGE with a pattern of being greater in BBMECs than in BAECs. AGE-induced ROS upregulation was attenuated by edaravone like AGE-induced TF upregulation. These results suggest that brain microvascular endothelial cells are more susceptible to AGE-induced TF upregulation than aortic endothelial cells, and that this susceptibility is associated with levels of intracellular ROS.     

Synergistic effect of local endothelial shear stress and systemic hypercholesterolemia on coronary atherosclerotic plaque progression and composition in pigs

Background

Systemic risk factors and local hemodynamic factors both contribute to coronary atherosclerosis, but their possibly synergistic inter-relationship remains unknown. The purpose of this natural history study was to investigate the combined in-vivo effect of varying levels of systemic hypercholesterolemia and local endothelial shear stress (ESS) on subsequent plaque progression and histological composition.

Methods

Diabetic, hyperlipidemic swine with higher systemic total cholesterol (TC) (n = 4) and relatively lower TC levels (n = 5) underwent three-vessel intravascular ultrasound (IVUS) at 3–5 consecutive time-points in-vivo. ESS was calculated serially using computational fluid dynamics. 3-D reconstructed coronary arteries were divided into 3 mm-long segments (n = 595), which were stratified according to higher vs. relatively lower TC and low (< 1.2 Pa) vs. higher local ESS (≥ 1.2 Pa). Arteries were harvested at 9 months, and a subset of segments (n = 114) underwent histopathologic analyses.

Results

Change of plaque volume (ΔPV) by IVUS over time was most pronounced in low-ESS segments from higher-TC animals. Notably, higher-ESS segments from higher-TC animals had greater ΔPV compared to low-ESS segments from lower-TC animals (p < 0.001). The time-averaged ESS in segments that resulted in significant plaque increased with increasing TC levels (slope: 0.24 Pa/100 mg/dl; r = 0.80; p < 0.01). At follow-up, low-ESS segments from higher-TC animals had the highest mRNA levels of lipoprotein receptors and inflammatory mediators and, consequently, the greatest lipid accumulation and inflammation.

Conclusions

This study redefines the principle concept that “low” ESS promotes coronary plaque growth and vulnerability by demonstrating that: (i.) the pro-atherogenic threshold of low ESS is not uniform, but cholesterol-dependent; and (ii.) the atherogenic effects of local low ESS are amplified, and the athero-protective effects of higher ESS may be outweighed, by increasing cholesterol levels. Intense hypercholesterolemia and very low ESS are synergistic in favoring rapid atheroma progression and high-risk composition.     

Defensive active coping facilitates chronic hyperglycaemia and endothelial dysfunction in African men: The SABPA study

Background

Dissociation between behavioural defensive active coping (AC) control albeit physiological “loss of control” responses was associated with silent ischaemia and structural wall abnormalities in African men. Whether it applies to structural alterations and endothelial dysfunction is uncertain. We therefore aimed to determine AC ethnic-gender specific receiver operating characteristic (ROC) carotid intima media far wall (CIMTf) cut points best associated with 24-h BP, -silent ischaemia and glycated haemoglobin (HbA1c).

Methods

Participants included African and Caucasians (N = 317) without pre-existing stroke or atrial fibrillation, aged 45 ± 9 years. The Coping Strategy Indicator was used to measure AC. Ultrasound CIMTf, ambulatory BP, silent ischaemia and fasting blood samples were obtained.

Results

Between 69 and 77% of AC African men showed above normal diastolic BP and HbA1c levels compared to 44–48% of AC Caucasian men. In AC African women, 41–60% showed above normal BP, silent ischaemia and HbA1c levels compared to 17–44% of their Caucasian counterparts. ROC curve analyses, detecting optimal CIMTf cut points, ranged between 0.57 and 0.65 mm (BP) and 0.71 and 0.74 mm (silent ischaemia) in AC ethnic-gender groups. Only HbA1C (> 5.7%), with a sensitivity/specificity 47%/74%, after controlling for confounders, predicted structural alterations at an optimal cut point of 0.69 mm in AC African men (OR 4.5; 95% CI 2.93–18.73).

Conclusion

Novel findings of behavioural resilience were apparent in the AC African female despite a high prevalence of risk markers. In AC males, chronic hyperglycaemia facilitated endothelial dysfunction, i.e. a physiological “loss of control” and susceptibility to stroke risk.