Improvement of Function and Morphology of Tumor Necrosis Factor-.ALPHA. Treated Endothelial Cells With 17-.BETA. Estradiol A Preliminary Study for a Feasible Simple Model for Atherosclerosis

Human Umbilical Vein Endothelial Cells as a Versatile Cellular Model System in Diverse Experimental Paradigms: An Ultrastructural Perspective

Human umbilical vein endothelial cells (HUVECs) are primary cells isolated from the vein of an umbilical cord, extensively used in cardiovascular studies and medical research. These cells, retaining the characteristics of endothelial cells in vivo, serve as a valuable cellular model system for understanding vascular biology, endothelial dysfunction, pathophysiology of diseases such as atherosclerosis, and responses to different drugs or treatments. Transmission electron microscopy (TEM) has been a cornerstone in revealing the detailed architecture of multiple cellular model systems including HUVECs, allowing researchers to visualize subcellular organelles, membrane structures, and cytoskeletal elements. Among them, the endoplasmic reticulum, Golgi apparatus, mitochondria, and nucleus can be meticulously examined to recognize alterations indicative of cellular responses to various stimuli. Importantly, Weibel-Palade bodies are characteristic secretory organelles found in HUVECs, which can be easily distinguished in the TEM. These distinctive structures also dynamically react to different factors through regulated exocytosis, resulting in complete or selective release of their contents. This detailed review summarizes the ultrastructural features of HUVECs and highlights the utility of TEM as a pivotal tool for analyzing HUVECs in diverse research frameworks, contributing valuable insights into the comprehension of HUVEC behavior and enriching our knowledge into the complexity of vascular biology.

Phenotypic alterations in human saphenous vein culture induced by tumor necrosis factor-alpha and lipoproteins: a preliminary development of an initial atherosclerotic plaque model

Background

Atherosclerosis is a chronic progressive inflammatory disease of blood vessels particularly the arteries. The development of atherosclerotic plaques or atherogenesis is a complex process that is influenced by cardiovascular risk factors such as vascular inflammation and dyslipidemia. This study demonstrates the ability of tumor necrosis factor-alpha (TNF-α) and low density lipoproteins (LDL) to induce atherosclerotic plaque in human saphenous vein (HSV) organ culture.

Methods

Normal HSV segments, from male patients who had coronary bypass graft, were cultured in DMEM containing 5% heat inactivated fetal bovine serum. TNF-α (5 ng/ml) was applied in combination with native LDL (nLDL) or oxidized LDL (oxLDL) at the dose of 50 μg/ml for 14 days. The phenotypic changes of the organ cultures characteristic of initial atherosclerotic plaques were evaluated. The effect of anti-atherogenic agent, 17-β estradiol (E₂), was also determined.

Results

Histologic, histomorphometric, and immunohistochemical examinations revealed that HSV rings stimulated with TNF-α + nLDL or TNF-α + oxLDL can exhibit the essential morphological features of atherogenesis, including fibrous cap formation, cholesterol clefts, evident thickening of the intimal layer, increased proliferation of smooth muscle cells (SMC) and migration to the subendothelial layer, significant SMC foam cell formation, and increased expression of adhesion molecules in the vascular wall. Addition of E₂ (50 nM) to the culture significantly modulated the critical changes. Consistently, mRNA profiling of the HSV model revealed that 50 of 84 genes of atherosclerosis were up-regulated.

Conclusions

Phenotypic changes characteristic of the initial development of atherosclerotic plaques can be induced in HSV organ culture.

Pregnancy followed by delivery may affect circulating soluble lectin-like oxidized low-density lipoprotein receptor-1 levels in women of reproductive age

Background/Objective. It is known that menopause or lack of endogenous estrogen is a risk factor for endothelial dysfunction and CAD. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is involved inmultiple phases of vascular dysfunction.The purpose of the current study was to determine the association between soluble LOX-1 (sLOX-1) and pregnancy followed by delivery in women of reproductive age. Materials/Methods. Sixty-eight subjects with pregnancy followed by delivery (group 1) and 57 subjects with nongravidity (group 2) were included in this study. Levels of sLOX-1 were measured in serum by EL SA. Results. Plasma levels of sLOX-1 were significantly lower in Group 1 than Group 2 in women of reproductive age (0.52 ± 0.18 ng/mL and 0.78 ± 0.13, resp., P < 0.001). There were strong correlations between sLOX-1 levels and the number of gravida (r = −0.645, P < 0.001). The levels of sLOX-1 highly correlated with the number of parous (r = −0.683, P < 0.001). Conclusion. Our study demonstrated that serum sLOX-1 levels were associated with pregnancy followed by delivery that might predict endothelial dysfunction. We conclude that pregnancy followed by delivery may delay the beginning and progress of arteriosclerosis and its clinical manifestations in women of reproductive age.

S-allyl-L-cysteine sulfoxide inhibits tumor necrosis factor-alpha induced monocyte adhesion and intercellular cell adhesion molecule-1 expression in human umbilical vein endothelial cells

Garlic and its water-soluble allyl sulfur-containing compound, S-Allyl-L-cysteine Sulfoxide (ACSO), have shown antioxidant and anti-inflammatory activities, inhibiting the development of atherosclerosis. However, little is known about the mechanism(s) underlying the therapeutic effect of ACSO in inhibiting the formation of atherosclerostic lesion. This study aimed to investigate whether ACSO could modulate tumor necrosis factor-alpha (TNF-alpha)-induced expression of intercellular cell adhesion molecule-1, monocyte adhesion and TNF-alpha-mediated signaling in human umbilical vein endothelial cells. While TNF-alpha promoted the intercellular cell adhesion molecule-1 mRNA transcription in a dose- and time-dependent manner, ACSO treatment significantly reduced the levels of TNF-alpha-induced intercellular cell adhesion molecule-1 mRNA transcripts (P < 0.01). Furthermore, ACSO dramatically inhibited TNF-alpha triggered adhesion of THP-1 monocytes to endothelial cells and porcine coronary artery rings. Moreover, ACSO mitigated TNF-alpha induced depolarization of mitochondrial membrane potential and overproduction of superoxide anion, associated with the inhibition of NOX4, a subunit of nicotinamide adenine dinucleotide phosphate-oxidase, mRNA transcription. In addition, ACSO also inhibited TNF-alpha-induced phosphorylation of JNK, ERK1/2 and IkappaB, but not p38. Apparently, ACSO inhibited proinflammatory cytokine-induced adhesion of monocytes to endothelial cells by inhibiting the mitogen-activated protein kinase signaling and related intercellular cell adhesion molecule-1 expression, maintaining mitochondrial membrane potential, and suppressing the overproduction of superoxide anion in endothelial cells. Therefore, our findings may provide new insights into ACSO on controlling TNF-alpha-mediated inflammation and vascular disease.

Delivery may affect arterial elasticity in women

BACKGROUND

Estrogen is considered to be cardioprotective, but estrogen replacement therapy for postmenopausal women has not shown results for either primary or secondary cardiovascular event prevention. During normal pregnancy, women have significantly higher levels of estrogen and it may be endogenous estrogen that helps prevent atherosclerosis.

METHODS AND RESULTS

The present cross-sectional study examined the association between pregnancy followed by delivery and clinical atherosclerosis using the brachial-ankle pulse wave velocity (PWV). A total of 2,560 women undergoing annual health screening at the Institute of Hyogo Prefecture Health Promotion Association in Japan were recruited. Pregnancy history (the age of menarche/menopause and the number of gravida/para), conventional coronary risk factors, and brachial-ankle PWV were recorded. Multivariate linear regression by stepwise selection analysis demonstrated that women who had 1 or more deliveries had a significantly lower PWV, independent of age and other conventional coronary risk factors.

CONCLUSIONS

Pregnancy followed by delivery may decrease arterial stiffness and prevent the progress of atherosclerosis in women. The contribution of such a pregnancy followed by delivery-related decrease in arterial stiffness to the reduction of cardiovascular disease in women should be further evaluated.

Ginsenoside Rb1 inhibits tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression in human endothelial cells

We investigated whether ginsenoside Rb1 (Rb1) could block tumor necrosis factor-alpha (TNF-alpha)-induced over-expression of vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells (HUVECs) and human lung microvascular endothelial cells (HMVECs-L). Cells were treated with various concentrations of TNF-alpha with or without Rb1 pre-treatment for 16 h. The mRNA and protein levels of VCAM-1 were determined with real-time polymerase chain reaction (PCR) and flow cytometry, respectively. Human monocytic THP-1 cells labeled with fluorescent dye (Calcein-AM) was used for the adhesion assay on HUVEC monolayers. Dihydroethidium (DHE) was used to demonstrate in situ levels of superoxide production. JC-1 dye was used to measure changes in mitochondrial membrane potential. Activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappaB (NF-kappaB) was determined by Bio-Plex immunoassay. TNF-alpha treatment significantly increased the mRNA and protein levels of VCAM-1 in HUVECs in a dose dependent manner. Rb1 pre-treatment effectively blocked the TNF-alpha-induced expression of VCAM-1 mRNA or protein by 80% and 43%, respectively (p<0.01). THP-1 adhesion was also blocked. Furthermore, Rb1 reduced the TNF-alpha-induced increase of superoxide anion production by 41% and inhibited the TNF-alpha-induced decrease of mitochondrial membrane potential by 44% in HUVECs. Rb1 also effectively blocked TNF-alpha-induced activation of p38, c-Jun N-terminal protein kinase, extracellular signal-regulated kinase 1/2 and IkappaBalpha. In conclusion, Rb1 effectively blocked the TNF-alpha-induced over-expression of VCAM-1, increased THP-1 adhesion and over-production of superoxide anion. Furthermore, Rb1 inhibited TNF-alpha-induced MAPKs and NF-kappaB activation. These data suggested that Rb1 might have potential therapeutic effects in controlling inflammation in vascular diseases.

Increased serum glycated albumin level is associated with the presence and severity of coronary artery disease in type 2 diabetic patients

BACKGROUND

Glycated albumin is the predominant circulating Amadori-type glycated protein in vivo and plays a major role in the development of diabetic vascular complications. The aim of this study was to assess the relationship between increased serum glycated albumin level and the presence and severity of coronary artery disease (CAD) in patients with type 2 diabetes mellitus (T2DM).

METHODS AND RESULTS

In a total of 320 consecutive patients with T2DM, coronary angiography revealed normal coronary arteries in 83 patients (control group) and significant coronary stenosis (> or = 70% luminal diameter narrowing) in 237, of whom 51 patients had 1-vessel disease (Group I), 80 had 2-vessel disease (Group II), and 106 had 3-vessel disease (Group III). Serum glycated albumin, hemoglobin A(1c) (HbA(1c)) and tumor necrosis factor (TNF)-alpha levels, lipid profile, and renal function were measured. Logistic regression analysis was performed to determine the relative risk of serum glycated albumin level for the presence and severity of CAD. Multivariate stepwise linear regression analysis was done to identify independent determinants of the glycated albumin level. Serum glycated albumin (21.2+/-5.3% vs 19.4+/-4.3%, p=0.005) and TNF-alpha levels (123 +/-115 pg/ml vs 65+/-59 pg/ml, p<0.001) were significantly higher in patients with CAD than in controls, but serum HbAlc level did not significantly differ between them (7.6+/-1.3% vs 7.4+/-1.2%, p=0.19). There was a significant difference in serum glycated albumin level between Groups I and III (19.5+/-3.3% vs 21.8+/-5.7%, p<0.001). The serum glycated albumin level correlated with the number of diseased arteries (Spearman r=0.205, p<0.001), and was closely related to serum levels on admission of glucose (r=0.495, p<0.001), TNF-alpha (r=0.123, p=0.028), blood urea nitrogen (r=0.167, p=0.004), triglycerides (r=0.129, p=0.021), and HbA(1c) (r=0.795, p<0.001). Multivariate analysis indicated that serum levels of glucose (p<0.0001), TNF-alpha (p=0.001), blood urea nitrogen (p=0.004) and triglycerides (p=0.035) were independent determinants for glycated albumin. Logistic regression analysis revealed that glycated albumin > or = 19% (odds ratio (OR) 2.9, p<0.001) was an independent predictor for CAD and glycated albumin > or = 21% (OR 2.3, p=0.032) for 3-vessel disease prediction. The area under the receiver-operating characteristic curve for glycated albumin (0.620, 95% confidence interval (CI) 0.548 to 0.691, p=0.001) was superior to that for HbA(1c) (0.543, 95% CI 0.473 to 0.613, p=0.243).

CONCLUSIONS

An increased serum level of glycated albumin is associated with the presence and severity of CAD, and may be useful in screening patients with T2DM.

Remnant-like lipoprotein particles impair endothelial function: direct and indirect effects on nitric oxide synthase

Remnant-like lipoprotein particles (RLPs) have been implicated as potentially atherogenic lipoproteins. Endothelial dysfunction is known to be an early event in atherosclerosis and an important contributor to the pathogenesis of coronary artery disease. Moreover, there is considerable evidence linking increased RLP cholesterol levels with endothelial dysfunction, reflected by impaired endothelial vasodilatation and abnormal endothelial secretion. The underlying mechanisms by which RLPs may contribute to endothelial dysfunction are complex and have not been completely elucidated. Because the expression and activation of endothelial nitric oxide synthase (eNOS) are vital to endothelial function, and recent data have implied an association between RLPs and eNOS, this manuscript proposes the hypothesis that RLPs could impair endothelial function via direct and indirect effects on eNOS: RLPs may affect the autophosphorylation of focal adhesion kinase and its downstream phosphatidylinositol kinase/Akt (protein kinase B) signaling pathway, resulting in eNOS inactivation through induction of intracellular oxidative stress in endothelial cells; and RLPs could affect the expression or activation of eNOS indirectly by stimulating secretion of various inflammatory factors from multiple origins. The practical applications of this manuscript provide new insights for the future investigation of RLPs.

Changes in coronary resistance related to the stages of the female life cycle

BACKGROUND

Estrogen is known to dilate the coronary vascular system mainly through nitric oxide (NO) release. However, it has not been determined whether or not this effect occurs equally throughout all stages of the female life cycle. We examined the changes in coronary flow properties in adolescent, adult and ovariectomized (OVX) female rats using the endothelial NO synthetase blocker, L-N (omega) nitroarginine (L-NNA).

METHODS AND RESULTS

Female rats were divided into 3 groups: adolescent (13 weeks, n=6), adult (19 weeks, n=8) and OVX (20 weeks, n=7, 12 weeks after oophorectomy). Coronary effluent was measured using the Langendorff non-working heart model before and 15 min after the use of L-NNA. In OVX rats, coronary effluent was significantly decreased in comparison with adolescent and adult rats (adolescent vs OVX: p<0.001; adult vs OVX: p<0.05). After treatment with L-NNA, coronary effluent was significantly higher in the adolescent group compared with the adult and OVX groups (adolescent vs adult: p<0.01; adolescent vs OVX: p<0.0005).

CONCLUSIONS

Oophorectomy brought about an increase in coronary vascular resistance. L-NNA exacerbated coronary vascular resistance in relation to maturation. It is suggested that the effect of estrogen on vascular dilatation in adolescents is largely dependent on a non-NO pathway, whereas adults are largely dependent on an NO pathway.

Nitric oxide (NO) is a new clinical biomarker of survival in the elderly patients and its efficacy might be nearly equal to albumin

BACKGROUND

For elderly patients, the consideration of prognostic factors is very important, but there have been few reports about the potential use of vasoactive substances as prognostic markers in the elderly.

OBJECTIVE

We assessed endocrinological substances, such as plasma NO(x) (metabolites of NO), as the prognostic marker in elderly. We compared their efficacy with that of such well-known markers as albumin and pro-inflammatory cytokines such as IL-6.

METHODS

The patients were recruited consequently from the clinics of Nagoya University Hospital or related home care services facilities. One hundred and twenty seven elderly aged 65 and older were registered. Biochemical analyses such as albumin, total cholesterol, BNP, and NO(x) were measured upon enrollment. The main outcome was the survival rate.

RESULTS

Forty-six patients died during the follow-up period. Mann-Whitney's U-test showed that the levels of age, hemoglobin, total protein, serum albumin, serum creatinine, total cholesterol, HDL-cholesterol, LDL-cholesterol, high sensitive CRP, NO(x), IL-6, and TNF-alpha were significantly different between the living and deceased subjects. Among the dependent variables in the logistic regression analyses, only albumin and NO(x) were significantly different. In the Kaplan-Meier analyses of mortality, the prognosis of patients in 3rd and 4th quartile of NO(x) was significantly worse than that in 1st or 2nd quartile.

CONCLUSION

NO(x) has potential both as a vascular marker and as a marker for predicting survival in elderly. In the latter role, it may be as effective as albumin.

Tumor-Necrosis-Factor-.ALPHA.-Gene-Deficient Mice Have Improved Cardiac Function Through Reduction of Intercellular Adhesion Molecule-1 in Myocardial Infarction

BACKGROUND

Tumor necrosis factor (TNF)-alpha is linked to the pathogenesis of cardiovascular diseases, but how it affects myocardial infarction (MI), so the present study examined the effects of TNF-alpha and the involvement of intercellular adhesion molecule (ICAM)-1 on MI.

METHODS AND RESULTS

Left coronary arteries of C57BL/6 wild type (WT) and TNF-alpha knockout (KO) mice were ligated and the mice were killed 1, 3, and 7 days later. Fractional shortening on echocardiography of the KO mice was significantly higher than that of the WT mice from day 1 to 7 (p<0.01). The ICAM-1 mRNA in the infarcted area of the KO mice was significantly lower than that of the WT from day 1 (p<0.01) to 7. In immunohistochemistry, the expression of ICAM-1 was weaker in the KO than in the WT mice. The number of neutrophils in the KO mice peaked at day 1, but even this peak level failed to reach the levels in the infarcted (p<0.01) and peri-infarcted areas (p<0.05) in the WT. The number of macrophages in the KO mice peaked at day 7, but this peak level failed to reach the levels in the infarcted (p<0.01) and peri-infarcted areas (p<0.05) in the WT.

CONCLUSION

In a permanent occlusion model of MI TNF-alpha decreased cardiac function and ameliorated myocardial remodeling through the induction of ICAM-1.

Mechanisms Underlying Nano-Sized Air-Pollution-Mediated Progression of Atherosclerosis Carbon Black Causes Cytotoxic Injury/Inflammation and Inhibits Cell Growth in Vascular Endothelial Cells

BACKGROUND

Epidemiological studies indicate a significant link between exposure to environmental air pollution and mortality and morbidity from ischemic heart disease. Because nanoparticles can translocate into blood circulation, the present study aimed to clarify their direct effects on human vascular endothelial cells (ECs).

METHODS AND RESULTS

Human umbilical vein ECs (HUVECs) were treated with carbon black (CB), a component of diesel exhaust particles, for 24 h. CB induced cytotoxic morphological changes such as cytosolic vacuole formation, cell disorientation and decreased density. Lactate dehydrogenase assay revealed that CB induced cytotoxic injury in both the cells and plasma membranes. Proliferation assay showed that CB inhibited cell growth. Monocyte chemoattractant protein-1 but not vascular cell adhesion molecule-1 was induced by CB. CB reduced the expressions of connexin37 and endothelial nitric oxide (NO) synthase. Microarray analysis revealed the induction of pro-inflammatory molecules by CB.

CONCLUSIONS

The present results demonstrate for the first time that CB directly affects the endothelium, causing cytotoxic injury, inflammatory responses, and inhibition of cell growth. As EC injury/inflammation and membrane disintegration are related to the initiation of atherosclerosis, and NO is anti-atherogenic and anti-thrombogenic, the direct effects of nanoparticles on ECs may represent one mechanism behind environmental air pollution-mediated atherosclerosis and ischemic heart disease.

Scintigraphic Imaging of Endothelium-Dependent Vasodilation in the Forearm A Preliminary Report

BACKGROUND

The diagnosis of endothelial dysfunction has been gaining clinical importance, but although endothelial function testing is available in the research setting, no technique yet exists that is simple, safe, reproducible and easily performed as a clinical screening method. The aim of this study was to design a new, scintigraphic method of imaging the flow-mediated dilation in the forearm, which represents the functional characteristic of endothelial dysfunction.

METHODS AND RESULTS

The study group comprised 118 subjects in whom left forearm ischemia was induced by inflating a sphygmomanometer cuff to supra systolic pressure for 4.5 min. Later, dynamic acquisition (2 s frame/min) was initiated after the injection of technetium-99m methoxy-isobutyl isonitril into the dorsal pedal veins. Equivalent regions of interest were drawn on both arms to detect total activity counts during 1 min and the perfusion ratios (left arm/right arm) were calculated. The left arm counts (22,203.3+/-12,372.7) were significantly higher than the right arm counts (9,980.9+/-5,931.9) (p<0.001). A significant decrease in perfusion ratios was noted in the hypertension and hypercholesterolemia groups. An increase in the number of risk factors caused an insignificant decrease in perfusion ratio (p=0.346).

CONCLUSION

Non-invasive evaluation of endothelium-dependent vasodilation by semiquantitative scintigraphic method using radioactive perfusion tracer provided promising results.

Pregnancy-Related Hyperlipidemia and Endothelial Function in Healthy Women

BACKGROUND

The purpose of the present study was to investigate pregnancy-related changes in the maternal serum lipid profile and endothelial function.

METHODS AND RESULTS

As part of the population-based, prospective cohort Cardiovascular Risk in Young Finns study conducted in Finland, 57 pregnant Finnish women and 62 control women matched for age and smoking were examined throughout gestation. Serum triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were determined and concomitantly endothelium-dependent brachial artery flow mediated dilation (FMD) was measured by ultrasound. During pregnancy serum TC, LDL-C, HDL-C, TG and very-low-density lipoprotein cholesterol increased significantly when compared with the non-pregnant state (p<0.001 for each) and towards the end of pregnancy (p<0.001, p<0.001, p=0.007, p<0.001, p<0.001). FMD increased towards the end of pregnancy and there was a statistically significant direct correlation between gestational age and FMD% (r=0.345, p=0.010). Brachial artery diameter at rest and FMD% were negatively correlated in pregnant (r=-0.280, p=0.035) and non-pregnant women (r=-0.360, p<0.004). The univariate correlation analysis showed a direct correlation between maternal serum TC (r=0.333, p=0.012) and TG (r=0.366, p=0.006) and FMD%, whereas a negative non-significant correlation was found in non-pregnant women. In a multivariate model, vessel size (beta=-0.436, p=0.001) and TG (beta=0.502, p<0.001) were the most powerful predictors for FMD% in pregnancy, the influence of other lipids was non-significant.

CONCLUSIONS

In healthy pregnant women increased gestational age is associated with improved endothelium-dependent vasodilation responses regardless of concurrently appearing lipid changes.