Levels of soluble E-selectin and ICAM-1 in the coronary circulation of patients with stable coronary artery disease: association with the severity of coronary atherosclerosis

Selectins in Biology and Human Disease: Opportunity in E-selectin Antagonism

Selectins are cell adhesion proteins discovered in the 1980s. As C-type lectins, selectins contain an essential calcium ion in the ligand-binding pocket and recognize the isomeric tetrasaccharides sialyl Lewisx (sLex) and sialyl Lewisa (sLea). Three selectins, E-selectin, P-selectin, and L-selectin, play distinct, complementary roles in inflammation, hematopoiesis, and tumor biology. They have been implicated in the pathology of diverse inflammatory disorders, and several selectin antagonists have been tested clinically. E-selectin plays a unique role in leukocyte activation, making it an attractive target for intervention, for example, in sickle cell disease (SCD). This review summarizes selectin biology and pathology, structure and ligand binding, and selectin antagonists that have reached clinical testing with an emphasis on E-selectin.

Endothelial Dysfunction, Inflammation and Coronary Artery Disease: Potential Biomarkers and Promising Therapeutical Approaches

Coronary artery disease (CAD) and its complications are the leading cause of death worldwide. Inflammatory activation and dysfunction of the endothelium are key events in the development and pathophysiology of atherosclerosis and are associated with an elevated risk of cardiovascular events. There is great interest to further understand the pathophysiologic mechanisms underlying endothelial dysfunction and atherosclerosis progression, and to identify novel biomarkers and therapeutic strategies to prevent endothelial dysfunction, atherosclerosis and to reduce the risk of developing CAD and its complications. The use of liquid biopsies and new molecular biology techniques have allowed the identification of a growing list of molecular and cellular markers of endothelial dysfunction, which have provided insight on the molecular basis of atherosclerosis and are potential biomarkers and therapeutic targets for the prevention and or treatment of atherosclerosis and CAD. This review describes recent information on normal vascular endothelium function, as well as traditional and novel potential biomarkers of endothelial dysfunction and inflammation, and pharmacological and non-pharmacological therapeutic strategies aimed to protect the endothelium or reverse endothelial damage, as a preventive treatment for CAD and related complications.

Markers of Endothelial Dysfunction: E-selectin, Endothelin-1 and von Willebrand Factor in Patients with Coronary Heart Disease, Including in Combination with Type 2 Diabetes Mellitus

The prevalence of coronary heart disease (CHD) and type 2 diabetes mellitus (type 2 diabetes) in Russia and in the world continues to increase. Despite the prevention and optimization of therapy, CHD retains its leadership among all causes of death, and the mortality rate from type 2 diabetes and its complications gradually increases too. To improve the treatment of the above mentioned diseases, it is necessary to clarify the pathogenetic mechanisms of their development. The formation of endothelial dysfunction, characterized by an increase in the level of cell adhesion molecules and vasoconstriction, is a common link characteristic for the course and progression of CHD and type 2 diabetes. This article presents an analysis of preand clinical studies on the role of endothelial dysfunction markers: cell adhesion molecules (E-selectin), vasoconstriction (endothelin-1) and von Willebrand factor in patients with CHD, including those with type 2 diabetes mellitus.

Treatment of β-thujaplicin counteracts di(2-ethylhexyl)phthalate (DEHP)-exposed vascular smooth muscle activation, inflammation and atherosclerosis progression

The initiation of atherosclerosis involves up-regulation of molecules such as E-selectin, VCAM-1, and ICAM-1. The progression of atherosclerosis is linked to proliferation and migration of vascular smooth muscle cell via MMP-2 and MMP-9 activities. However, the etiology of atherosclerosis concerning plasticizers is unknown. We evaluated β-thujaplicin in preventing the development of atherosclerosis in a model induced by pro-inflammatory cytokines. Moreover, we established a new atherosclerosis model in vascular smooth muscle cells (VSMC) exposed to a common contact plasticizer, di(2-ethylhexyl)phthalate (DEHP). SEVC4-10 endothelial cells were treated with 50% RAW conditioned medium and A7r5 VSMC was treated with the plasticizer, with/without β-thujaplicin (4 or 12 μM). Production of E-selectin, ICAM-1, and VCAM-1 in SEVC4-10 cells as well as MMP-2/MMP-9 (both expression and activity) in VSMC were monitored. Results showed that the conditioned medium induced E-selectin and ICAM were significantly prevented by β-thujaplicin. However, inhibition on the production of VCAM by β-thujaplicin was only seen in a concentration of 12 μM. Both concentrations of β-thujaplicin also significantly prevented DEHP-induced MMP-2 and MMP-9 expression and activities. Evidence uncovers that β-thujaplicin has additional factors in amelioration of atherosclerosis and corroborates that β-thujaplicin is a strong candidate in preventing the initiation and progression of atherosclerosis.

Chinese Herbal Cardiotonic Pill Stabilizes Vulnerable Plaques in Rabbits by Decreasing the Expression of Adhesion Molecules

The cardiotonic pill (CP), consisting of a mixture of Radix Salviae Miltiorrhizae, Radix Notoginseng, and Borneolum Syntheticum, has been widely used in the prevention and treatment of cardiovascular disease. Adhesion molecules, including intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1, are involved in the development of vulnerable plaque. We investigated the effect of the CP in a rabbit model of vulnerable plaque established by local transfection with p53 gene. Compared with the control group, rabbits with vulnerable plaque showed a significantly lower intima-media thickness and plaque burden after CP treatment for 12 weeks. Moreover, the reduction in rate of plaque rupture and vulnerability index was similar. On enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and immunohistochemistry analysis, the expression of intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1 was inhibited with CP treatment. CP treatment could postpone atherosclerotic plaque development and stabilize vulnerable plaque by inhibiting the expression of adhesion molecules in treatment of cardiovascular disease.

Association of E-selectin with hematological, hormonal levels and plasma proteins in children with end stage renal disease

Background:

Hypercoagulable state is a common serious problem in patients with end-stage renal disease (ESRD). ESRD patients are in a condition of chronic inflammation. An increased level of E-selectin, “a key adhesion molecule that regulates leukocyte bindings to endothelium at damaged sites,” accompanies the higher risk of inflammation in ESRD patients. We aimed to investigate the possible correlation among E-selectin as an adhesion molecule, coagulation factors, and inflammatory factors in children with ESRD.

Materials and Methods:

Thirty-five child patients with ESRD who had been on regular dialysis treatment were registered in our study. Nighteen sex- and age-matched healthy volunteers were used as the control group. Laboratory tests were requested for the evaluation of hematological and biochemical parameters, and parathyroid hormone (PTH), and for coagulation state; fibrinogen, protein C, and protein S were measured. The enzyme-linked immunosorbent assay (ELISA) (Biomerica, CA, and IDS, UK). for serum E-selectin assay was provided by R and D Systems (Abingdon, UK).

Results:

Hemoglubolin (Hb), blood urea nitrogen (BUN), creatinine, calcium, PTH, triglyceride (TG) concentrations in serum as well as E-selectin showed significant difference between the two study groups, as indeed was expected. Serum E-selectin was significantly higher (P value = 0.033) in dialysis patients than in healthy subjects. E-selectin was positively correlated only with phosphorus in ESRD children (r = 0.398, P = 0.018). No association was found for other parameters.

Conclusion:

Although in our study circulating E-selectin concentration “as an inflammatory maker” is independently positively associated with limited blood markers, for better evaluation, well-designed cohort studies should be examined in ESRD children.

Soluble adhesion molecules as markers of native arteriovenous fistula thrombosis in children on uremia

Vascular access represents a lifeline for children undergoing hemodialysis. A failure of vascular access among patients receiving regular hemodialysis is associated with increased morbidity, mortality and costs. We assessed the possibility of using soluble adhesion molecules as reliable predictors of vascular access failure in children on hemodialysis. Moreover, we evaluated whether there is an association among the different studied adhesion molecules in hemodialysis patients with thrombosed and non-thrombosed arteriovenous fistula fistulas (AVFs). This study included 55 hemodialysis children, 36 with good access and 19 with access failure, and 20 healthy volunteers. Forty-four patients had native AVFs and 11 patients had tunneled permanent catheter (11with thrombosed and 33 with non-thrombosed AVFs). Serum-soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), soluble E-selectin (sE-selectin) and soluble P-selectin (sP-selectin) were measured using ELISA technique. A significant increase was found in the levels of sVCAM-1, sICAM-1, sE-selectin and sP-selectin versus controls and all hemodialysis patients, hemodialysis patients with good access and hemodialysis patients with access failure (P=0.001 for sVCAM-1 and sICAM-1 and P=0.0001 for sE-selectin and sP-selectin). A significant increase was found in the levels of sVCAM-1, sE-selectin and sP-selectin in both chronic hemodialysis patients with thrombosed and non-thrombosed native AVFs versus controls (P=0.0001 for all parameters). There was significant difference between both chronic hemodialysis patients with thrombosed and non-thrombosed native AVFs as regard to sVCAM-1 (54.64±30.82 versus 25.69±27.96ng/ml, P=0.04). Both sICAM-1 and sP-selectin were positively correlated with the erythropoietin (EPO) dose in hemodialysis children (r=0.31, P=0.04 and r=0.32, P=0.04, respectively). A significant positive association was found between E-selectin and sP-selectin in hemodialysis patients with thrombosed AVFs (r=0.83, P=0.04). There was a significant correlation between sVCAM-1 and EPO dose in thrombosed AVF group (r=0.84, P=0.01). The assessment of serum sVCAM-1 might be useful for the identification of the chronic hemodialysis patients at an increased risk for native AVFs thrombosis. The role of EPO in vascular access failure should be taken into consideration. The clinical relevance of these observations warrants further investigations.

Increased circulating macrophage migration inhibitory factor levels are associated with coronary artery disease

BACKGROUND

To evaluate the macrophage migration inhibitory factor and E-selectin levels in patients with acute coronary syndrome.

MATERIALS/METHODS

We examined the plasma migration inhibitory factor and E-selectin levels in 87 patients who presented with chest pain at our hospital. The patients were classified into two groups according to their cardiac status. Sixty-five patients had acute myocardial infarction, and 22 patients had non-cardiac chest pain (non-coronary disease). We designated the latter group of patients as the control group. The patients who presented with acute myocardial infarction were further divided into two subgroups: ST-elevated myocardial infarction (n = 30) and non-ST elevated myocardial infarction (n = 35).

RESULTS

We found higher plasma migration inhibitory factor levels in both acute myocardial infarction subgroups than in the control group. However, the E-selectin levels were similar between the acute myocardial infarction and control patients. In addition, we did not find a significant difference in the plasma migration inhibitory factor levels between the ST elevated myocardial infarction and NST-elevated myocardial infarction subgroups.

DISCUSSION

The circulating concentrations of migration inhibitory factor were significantly increased in acute myocardial infarction patients, whereas the soluble E-selectin levels were similar between acute myocardial infarction patients and control subjects. Our results suggest that migration inhibitory factor may play a role in the atherosclerotic process.

Assessment of the E-selectin rs5361 (561A>C) polymorphism and soluble protein concentration in acute coronary syndrome: association with circulating levels

Introduction. The acute coronary syndrome (ACS) is a complex disease where genetic and environmental factors are involved. E-selectin gene is a candidate for ACS progression due to its contribution in the inflammatory process and endothelial function. The rs5361 (561A>C) polymorphism in the E-selectin gene has been linked to changes in gene expression, affinity for its receptor, and plasmatic levels; therefore it is associated with an increased risk of cardiovascular disease. The aim of this study was to determine the association of the rs5361 polymorphism with ACS and to measure serum levels of soluble E-selectin (sE-selectin). Materials and Methods. 283 ACS patients and 205 healthy subjects (HS) from Western Mexico were included. The polymerase chain reaction-restriction fragment length polymorphism was used to determine the rs5361 polymorphism. The sE-selectin levels were measured by enzyme-linked immunosorbent assay. Results. Neither genotype nor allele frequencies of the rs5361 polymorphism showed statistical differences between groups. The sE-selectin levels were significantly higher in ACS patients compared to HS (54.58 versus 40.41 ng/ml, P = 0.02). The C allele had no effect on sE-selectin levels. Conclusions. The rs5361 E-selectin gene polymorphism is not a susceptibility marker for ACS in Western Mexico population. However, sE-selectin may be a biological marker of ACS.

Reduction of adhesion molecule production and alteration of eNOS and endothelin-1 mRNA expression in endothelium by Euphorbia hirta L. through its beneficial β-amyrin molecule

The inflammatory reaction in large blood vessels involves up-regulation of vascular adhesion molecules such as endothelial cell selectin (E-selectin), soluble vascular cell adhesion molecule (sVCAM)-1, and soluble intercellular adhesion molecule (sICAM)-1. These vascular dysfunctions are associated with the development of atherosclerosis. β-Amyrin, an active component of Euphorbia hirta L., has potent anti-inflammatory effects. So far, its preventive effects against the expression of inflammatory mediator-induced adhesion molecules have not been investigated. Endothelial cells (SVEC4-10 cell line) were treated with 50% RAW conditioned media (i.e., normal SVEC4-10 culture media contains 50% of lipopolysaccharide-activated macrophage culture media) without or with β-amyrin (0.6 and 0.3 µM). The production levels of E-selectin, sICAM-1, and sVCAM-1 in the SVEC4-10 cells were measured with ELISA assay kits. Under the same treatment conditions, expression of endothelin (ET)-1 and endothelial type of NO synthase (eNOS) mRNA were analyzed by RT-PCR and agarose gel. With β-amyrin, the 50% RAW conditioned media-induced E-selectin, sICAM-1, and sVCAM-1 levels as well as ET-1 gene expression were all suppressed. β-Amyrin treatment also restored the 50% RAW conditioned media-suppressed eNOS mRNA expression. These data indicate that β-amyrin is potentially useful in preventing chronic inflammation-related vascular diseases.

Chlorella 11-peptide inhibits the production of macrophage-induced adhesion molecules and reduces endothelin-1 expression and endothelial permeability

The inflammation process in large vessels involves the up-regulation of vascular adhesion molecules such as endothelial cell selectin (E-selectin), intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) which are also known as the markers of atherosclerosis. We have reported that Chlorella 11-peptide exhibited effective anti-inflammatory effects. This peptide with an amino sequence Val-Glu-Cys-Tyr-Gly-Pro-Asn-Arg-Pro-Gln-Phe was further examined for its potential in preventing atherosclerosis in this study. In particular, the roles of Chlorella 11-peptide in lowering the production of vascular adhesion molecules, monocyte chemoattractant protein (MCP-1) and expression of endothelin-1 (ET-1) from endothelia (SVEC4-10 cells) were studied. The production of E-selectin, ICAM-1, VCAM-1 and MCP-1 in SVEC4-10 cells was measured with ELISA. The mRNA expression of ET-1 was analyzed by RT-PCR and agarose gel. Results showed that Chlorella 11-peptide significantly suppressed the levels of E-selectin, ICAM, VCAM, MCP-1 as well as ET-1 gene expression. The inhibition of ICAM-1 and VCAM-1 production by Chlorella 11-peptide was reversed in the presence of protein kinase A inhibitor (H89) which suggests that the cAMP pathway was involved in the inhibitory cause of the peptide. In addition, this peptide was shown to reduce the extent of increased intercellular permeability induced by combination of 50% of lipopolysaccharide (LPS)-activated RAW 264.7 cells medium and 50% normal SEVC cell culture medium (referred to as 50% RAW-conditioned medium). These data demonstrate that Chlorella 11-peptide is a promising biomolecule in preventing chronic inflammatory-related vascular diseases.

P-selectin, E-selectin, and CD40L over time in chronic hemodialysis patients

The aim of this study was to measure P-selectin, E-selectin, and CD-4L levels over time in chronic hemodialysis (HD) patients. Thirty stable patients with end-stage renal failure undergoing chronic HD were included in the study. Blood samples were obtained before HD for measurement of P-selectin, E-selectin, and CD-40L. Measurements were performed at month 0 (T0), 3 (T2), 8 (T3), and 13 (T4). The levels of P-selectin, E-selectin, and CD40L were also analyzed according to the occurrence of cardiovascular disease (CVD) and to CVD-related mortality. The levels of CD40L and P-selectin changed significantly over time, decreasing at month 3 and 6 and returning at the T0 levels at month 13. Conversely, E-selectin levels did not. The levels of CD40L, P-selectin and E-selectin over time did not differ significantly between patients with age ≤ 65 or > 65 years, between patients with or without CVD, or between patients who died or who survived during the follow-up. In end-stage renal failure patients undergoing chronic HD, CD40L and P-selectin, but not E-selectin, showed a transient decrease over time, and the serum levels of these molecules were not associated with CVD or with CVD-related mortality.

Roles of SIRT1 in high glucose-induced endothelial impairment: association with diabetic atherosclerosis

BACKGROUND AND AIMS

We undertook this study to investigate the roles of SIRT1 in high glucose-induced endothelial impairment and their association with diabetic atherosclerosis.

METHODS

Otsuka Long-Evans Tokushima Fatty (OLETF) rats and nondiabetic rats of the same genetic background were included. Real-time PCR was used to detect SIRT1 mRNA expression in abdominal aorta at week 42. To further investigate the roles of SIRT1 on the function of endothelial cells in high glucose, human endothelial cells were treated with SIRT1 activator resveratrol for 24 h before being cultured in high glucose medium for 48 h.

RESULTS

Along with the early manifestation of atherosclerosis, SIRT1 mRNA level in OLETF group was significantly lower than that in control group (p <0.05). Compared with control cells, high glucose decreased nitric oxide (NO) secretion, but resveratrol treatment increased the expression of SIRT1 and the secretion of NO. After interfering with the expression of SIRT1 using SIRT1 siRNA, the effects of resveratrol on NO secretion were impaired. SIRT1 also counteracted the other pro-atherosclerotic effects of high glucose including the upregulating roles of high glucose on the expression of E-selectin mRNA and the downregulating roles of high glucose on the expression of endothelial nitric oxide synthase.

CONCLUSIONS

Decreased expression of SIRT1 in artery may be involved in the initiation and development of diabetic atherosclerosis. Increasing SIRT1 expression may hold great promise in the prevention and therapy of atherosclerosis in diabetic patients.

A chinese herbal preparation containing radix salviae miltiorrhizae, radix notoginseng and borneolum syntheticum reduces circulating adhesion molecules

Circulating adhesion molecules (CAMs), surface proteins expressed in the vascular endothelium, have emerged as risk factors for cardiovascular disease (CVD). CAMs are involved in intercellular communication that are believed to play a role in atherosclerosis. A Chinese medicine, the "Dantonic Pill" (DP) (also known as the "Cardiotonic Pill"), containing three Chinese herbal material medica, Radix Salviae Miltiorrhizae, Radix Notoginseng and Borneolum Syntheticum, has been used in China for the prevention and management of CVD. Previous laboratory and animal studies have suggested that this preparation reduces both atherogenesis and adhesion molecule expression. A parallel double blind randomized placebo-controlled study was conducted to assess the effects of the DP on three species of CAM (intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 and endothelial cell selectin (E-selectin)) in participants with mild-moderate hypercholesterolemia. Secondary endpoints included biochemical and hematological variables and clinical effects. Forty participants were randomized to either treatment or control for 12 weeks. Treatment with DP was associated with a statistically significant decrease in ICAM-1 (9% decrease, P = .03) and E-Selectin (15% decrease, P = .004). There was no significant change in renal function tests, liver function tests, glucose, lipids or C-reactive protein levels and clinical adverse effects did not differ between the active and the control groups. There were no relevant changes in participants receiving placebo. These results suggest that this herbal medicine may contribute to the development of a novel approach to cardiovascular risk reduction.

E-selectin and TFPI are associated with carotid intima-media thickness in stable IHD patients: the baseline findings of the MIAMI study

OBJECTIVE

MIAMI was a prospective multicenter clinical study designed to investigate the relationship between changes in carotid intima-media thickness (C-IMT) and those in the levels of circulating markers of inflammation, thrombosis and endothelial dysfunction. The study was performed in a group of stable coronary patients treated for two years with a moderate dosage of atorvastatin (20mg/day). In this paper the cross-sectional relationship between C-IMT and the same circulating markers of inflammation, thrombosis and endothelial dysfunction measured at baseline was investigated.

METHODS

Eighty-five subjects that had not used statins for at least two months were enrolled in the study. At time of enrollment, the levels of vascular cell adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1), E-selectin, interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-alpha, high-sensitivity C-reactive protein (hs-CRP), tissue factor (TF), tissue factor pathway inhibitor (TFPI), von Willebrand factor (vWF), fibrinogen, total cholesterol (TC), high-density lipoprotein (HDL) and low-density lipoprotein (LDL), and triglycerides were measured, in parallel with C-IMT assessment.

RESULTS

In cross-sectional analyses, markers of endothelial perturbation (i.e. E-selectin) and TFPI were more strongly correlated with arherosclerotic burden than markers of inflammation. The baseline picture in this study indicates that E-selectin and TFPI are linked with atherosclerotic burden.

The effects of exercise stress testing on soluble E-selectin, von Willebrand factor, and circulating endothelial cells as indices of endothelial damage/dysfunction

BACKGROUND

The quantification of circulating endothelial cells (CECs) in whole blood is an increasingly recognized index of endothelial damage/dysfunction. Abnormal CECs have been linked to the severity of coronary artery disease (CAD).

OBJECTIVE

We assessed the relationship of CECs to other markers of endothelial dysfunction (von Willebrand factor (vWF) and soluble E-selectin (sEsel)) during exercise stress testing (EST) in a cohort of patients with suspected CAD.

METHODS

We studied a cohort of patients referred to our chest pain clinic with a history of exertional chest pain. Treadmill EST was performed, using a full Bruce exercise protocol. Blood for CECs (immunobead method), vWF and sEsel (both ELISA) were collected immediately before (pre-exercise), immediately following exercise, and at 30 minutes post-EST.

RESULTS

We studied 31 patients (84% male; mean (SD) age 58.4 (9.8) years). Of the entire cohort, 14 patients (45.2%) had a positive EST. Exercise led to significant increases in levels of CECs, sEsel, vWF, white blood cells (WBC), heart rate, mean and systolic blood pressure compared with base-line (all P < 0.05). There was a significant correlation between the change (delta (immediate post-pre-exercise)) in CECs and delta vWF (r = 0.45; 95% CI 0.11-0.69: P = 0.01) and delta sEsel (r = 0.41; 0.05-0.7: P = 0.02), as well as between delta vWF and delta sEsel (r = 0.55; 0.25-0.76: P = 0.001). Neither absolute nor delta CEC counts were predictive of exercise work-load/functional capacity, nor the presence of positive EST results.

CONCLUSION

EST led to a significant increase in endothelial markers (CECs, vWF, and sEsel) compared with base-line levels. The rise in CECs correlated with the increases in other endothelial markers, but was not related to the either exercise workload/capacity or to the presence of a positive EST.

Circulating E-selectin as a risk marker in patients with end-stage renal disease

BACKGROUND

E-selectin is a key adhesion molecule which plays a fundamental role in endothelial progenitor cell-dependent reparative mechanisms in experimental ischaemia and it serves to anchor leucocytes to the endothelium in inflammatory processes. Inflammation is one of the strongest risk factors for death and cardiovascular (CV) events in end-stage renal disease (ESRD).

OBJECTIVE

The objective of the current study was to evaluate whether E-selectin is a useful biomarker of clinical outcome in ESRD patients. We tested the prediction power of circulating E-selectin for mortality and CV events in a cohort of 265 ESRD patients.

RESULTS

During the follow-up, 59 patients died and 58 had CV events. All-cause mortality was inversely related to serum E-selectin, the risk of death being the lowest in patients in the third E-selectin tertile (HR: 1, reference group), intermediate in those in the second tertile (HR: 1.30) and the highest in patients in the first tertile (HR: 2.02, P = 0.01). Similarly, the risk of fatal and nonfatal CV events followed an inverse pattern being lowest in the third tertile (reference group) and highest in the first tertile (HR: 1.73, P = 0.03). The prediction power of E-selectin for death and CV events was confirmed in a Cox regression analysis where E-selectin emerged as an inverse predictor of these outcomes, particularly so in patients with severe inflammation.

CONCLUSIONS

These data are in keeping with the hypothesis that in systemic inflammation altered E-selectin shedding may play a role in arterial damage and implicates this adhesion molecule in atherosclerotic complications in a high-risk condition like ESRD.

Cell-derived microparticles and exosomes in neuroinflammatory disorders

All blood cells and the vascular endothelium shed microparticles (MP) from their plasma membranes when suitably stimulated, and assay of MP in patient blood has found increasing application to the monitoring of disease states. In addition, mounting evidence suggests that MP are not mere epiphenomena but play significant roles in the pathophysiology of thromboses, inflammation, and cancers. This chapter endeavors to summarize the limited number of studies thus far done on MP in neurological disorders such as multiple sclerosis (MS), transient ischemic attacks, and the neurological manifestations of antiphospholipid syndrome (APS). In addition, the chapter offers some plausible hypotheses on possible roles of MP in the pathophsyiology of these disorders, chiefly, the hypothesis that MP are indeed important participants in some neuropathologies, especially those which are ischemic in nature, but probably also inflammatory ones. The chapter also goes over the history and general principles of MP studies (e.g., assay methods and pitfalls), comparison with alternative methods (e.g., soluble markers of disease states), subclasses of MP (such as exosomes), and other topics aimed at helping readers to consider MP studies in their own clinical fields. Tables include a listing of bioactive agents known to be carried on MP, many of which were heretofore considered strictly soluble, and some of which can be transferred from cell to cell via MP vectors, for example certain cytokine receptors.

Circulating markers of endothelial function in cardiovascular disease

Endothelial dysfunction is a key event in cardiovascular disease. Measurement of endothelial dysfunction in vivo presents a major challenge, but has important implications since it may identify the clinical need for therapeutic intervention, specifically in primary prevention. Several biological markers have been used as indicators of endothelial dysfunction. The soluble adhesion molecules sICAM-1 and sVCAM-1 lack specificity and are increased in inflammatory processes. Both markers are increased in coronary artery disease. sICAM-1 level predicts the risk for cardiovascular disease or diabetes mellitus in healthy individuals. sE-selectin is specific for the endothelium and is increased in coronary artery disease and diabetes mellitus. sE-selectin is also associated with diabetic risk. The endothelium-specific marker, soluble thrombomodulin, is associated with severity of coronary artery disease, stroke or peripheral occlusive arterial disease and is not increased in healthy or asymptomatic subjects. Interestingly, thrombomodulin decreases during treatment of hypercholesterolemia or hyperhomocysteinemia. In contrast, von Willebrand factor is the best endothelial biomarker and predicts risk for ischemic heart disease or stroke.

Endothelial microparticles correlate with high-risk angiographic lesions in acute coronary syndromes

BACKGROUND

Endothelial Microparticles (EMP) are small fragments of endothelial cell membrane shed during apoptosis or activation. Our group has previously reported elevations of EMP in patients with coronary artery disease (CAD), thrombotic thrombocytopenic purpura (TTP), pre-eclampsia, multiple sclerosis (MS), and severe hypertension (HTN). In the present study, we evaluate the possible relationship between EMP levels and the angiographic severity and characteristics of coronary obstructive lesions.

METHODS

We studied a total of 43 patients undergoing coronary angiography. Fifteen had presented with acute myocardial infarction (MI), 20 with unstable anginas (UA), 5 with stable angina (SA) and 3 with congestive heart failure. Coronary angiography was reviewed and coronary lesions were classified using the Ambrose classification. Coronary stenoses were classified as high and low risk. High-risk included lesions with eccentric appearance (type II), presence of thrombi, or multiple irregularities. Low-risk lesions were defined as concentric or type I. Lesions were also analyzed by degree of stenosis and history of acute coronary syndrome (ACS). EMP in plasma was assayed by flow cytometry.

RESULTS

EMP in eccentric type II or multiple irregular lesions (high-risk) were 2.5-fold higher than in type I or concentric (low-risk) lesions, p<0.05. Lesions with thrombi had three-fold higher EMP than those without (p=0.05). Mild stenosis (>20%-<45%) had three-fold higher EMP than more severe (>45%), and five-fold higher than those without stenosis (p<0.01). Among patients with type II lesions, those with first ACS episode had four-fold higher EMP levels than those with recurrent ACS (p<0.01).

CONCLUSION

High EMP was associated with high-risk angiographic lesions including eccentric type II, multiple irregular, and lesions with thrombi. Mild to moderate stenosis was associated with higher EMP levels than severe stenosis. EMP may be a useful marker in detecting endothelial injury and risk of ACS as defined by angiography.

Intracellular proatherogenic events and cell adhesion modulated by extracellular thiol/disulfide redox state

BACKGROUND

Oxidative stress, a contributing factor to atherosclerosis, causes oxidation of biological thiols, which can be quantified in terms of the thiol/disulfide redox. The major thiol/disulfide redox couple in human plasma is cysteine (Cys) and its disulfide, cystine (CySS). Although atherosclerosis has previously been associated with Cys/CySS oxidation, whether oxidation of Cys/CySS contributes in a causal way to atherosclerosis development is not known. We examined the function of extracellular Cys/CySS redox potential (E(h)) in the regulation of early events of atherosclerosis using cultured aortic endothelial cells and monocytes as a vascular model system.

METHODS AND RESULTS

To determine the range of thiol/disulfide redox state in human plasma, we analyzed levels of Cys, CySS, glutathione (GSH), and glutathione disulfide (GSSG) and calculated E(h) according to the Nernst equation. E(h) of Cys/CySS and GSH/GSSG was -120 to -20 and -200 to -50 mV, respectively. To approximate this range, endothelial cells were exposed to initial E(h) from -150 mV (most reduced) to 0 mV (most oxidized). Compared with more reduced E(h), oxidized E(h) of Cys/CySS stimulated H2O2 but not nitric oxide production, activated nuclear factor-kappaB, increased expression of adhesion molecules (intercellular adhesion molecule-1, platelet endothelial cell adhesion molecule-1, P-selectin), and stimulated monocytes binding to endothelial cells. Extracellular E(h) regulated thiol/disulfide redox states of extracellular membrane proteins and H2O2 production, indicating that variation in extracellular E(h) is detected and signaled at the cell surface.

CONCLUSIONS

The extracellular thiol/disulfide E(h) of the Cys/CySS couple plays a key role in regulating early events of atherosclerosis and could be useful as a potential marker for vascular disease risk.

Plasma Concentrations of Monocyte Chemoattractant Protein 1 (MCP-1) and Neopterin in the Coronary Circulation of Patients With Coronary Artery Disease-Association With the Severity of Coronary Atherosclerosis-

BACKGROUND

The dynamics of MCP-1 and neopterin and the relation between their concentrations in coronary circulation and the severity of coronary atherosclerosis were evaluated in patients with stable coronary artery disease (CAD).

METHODS AND RESULTS

Blood samples were obtained from the aortic root (Ao) and coronary sinus (CS) of 78 patients who underwent coronary angiography. Plasma MCP-1 and neopterin concentrations were measured using an enzyme-linked immunosorbent assay method and the CS-Ao differences were calculated. The severity of coronary heart disease (CHD) was evaluated in 52 patients who had no history of coronary angioplasty, using 3 coronary scoring systems: the clinical 1- to 3-vessel disease score, the American Heart Association extension score (1-15 segments), and the Gensini score. The plasma MCP-1 and neopterin concentrations increased significantly with age. The CS-Ao differences for neopterin showed weak, but significant, positive correlation with the Gensini score (r=0.347, p=0.013). There were no correlations among the MCP-1 concentrations in the Ao or CS, or in the CS-Ao difference, with the severity of CHD.

CONCLUSIONS

The results indicate that neopterin is a useful marker of the severity of coronary atherosclerosis in patients with stable CAD, acting as an index of the activity of monocytes/macrophages.