Levels of soluble cell adhesion molecules in patients with angiographically defined coronary atherosclerosis

Soluble Forms of Intercellular and Vascular Cell Adhesion Molecules Independently Predict Progression to Type 2 Diabetes in Mexican American Families

Objective

While the role of type 2 diabetes (T2D) in inducing endothelial dysfunction is fairly well-established the etiological role of endothelial dysfunction in the onset of T2D is still a matter of debate. In the light of conflicting evidence in this regard, we conducted a prospective study to determine the association of circulating levels of soluble intercellular adhesion molecule 1 (sICAM-1) and soluble vessel cell adhesion molecule 1 (sVCAM-1) with incident T2D.

Methods

Data from this study came from 1,269 Mexican Americans of whom 821 initially T2D-free individuals were longitudinally followed up in the San Antonio Family Heart Study. These individuals were followed for 9752.95 person-years for development of T2D. Prospective association of sICAM-1 and sVCAM-1 with incident T2D was studied using Kaplan-Meier survival plots and mixed effects Cox proportional hazards modeling to account for relatedness among study participants. Incremental value of adhesion molecule biomarkers was studied using integrated discrimination improvement (IDI) and net reclassification improvement (NRI) indexes.

Results

Decreasing median values for serum concentrations of sICAM-1 and sVCAM-1 were observed in the following groups in this order: individuals with T2D at baseline, individuals who developed T2D during follow-up, individuals with prediabetes at baseline and normal glucose tolerant (NGT) individuals who remained T2D-free during follow-up. Top quartiles for sICAM-1 and sVCAM-1 were strongly and significantly associated with homeostatic model of assessment—insulin resistance (HOMA-IR). Mixed effects Cox proportional hazards modeling revealed that after correcting for important clinical confounders, high sICAM-1 and sVCAM-1 concentrations were associated with 2.52 and 1.99 times faster progression to T2D as compared to low concentrations, respectively. Individuals with high concentrations for both sICAM-1 and sVCAM-1 progressed to T2D 3.42 times faster than those with low values for both sICAM-1 and sVCAM-1. The results were similar in women in reproductive age group and the remainder of the cohort. Inclusion of sICAM-1 and sVCAM-1 in predictive models significantly improved reclassification and discrimination. The majority of these results were seen even when the analyses were restricted to NGT individuals.

Conclusion

Serum concentrations of sICAM-1 and sVCAM-1 independently and additively predict future T2D and represent important candidate biomarkers of T2D.

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.

Decreased serum fetuin-A levels are associated with coronary artery diseases

BACKGROUND

To analyze Fetuin-A levels and soluble cellular adhesion molecules in patients with acute coronary syndrome.

METHODS AND RESULTS

Serum Fetuin-A and intercellular adhesion molecule-1 (sICAM-1), vascular cellular adhesion molecule-1 (sVCAM-1) levels were examined in 127 patients who presented with chest pain. These patients were classified in three groups: stable angina (SA, n=51), myocardial infarction (MI, n=34) and non-cardiac group (n=42). Logarithmic transformations were made for Fetuin-A levels. Log-Fetuin-A levels were higher in non-cardiac subjects compared to MI and SA patients (p<0.05). Patients with SA showed lower levels than controls but higher levels as compared to MI patients. After controlling for age and gender, levels of sVCAM-1 and sICAM-1 in patients with coronary atherosclerosis were not different from those in non-cardiac subjects.

CONCLUSION

Serum levels of soluble VCAM-1, ICAM-1 were not related to coronary artery disease (CAD), but fetuin-A levels seems to be decreased in SA and MI patients. Low fetuin-A may play a role in the pathophysiology of CAD.

Positive association of adiponectin with soluble vascular cell adhesion molecule sVCAM-1 levels in patients with vascular disease or dyslipidemia

The aim of our study was to evaluate the relationship of adiponectin to soluble forms of vascular cell adhesion molecule-1 (sVCAM-1) and intercellular cell adhesion molecule-1 (sICAM-1) in patients with cardiovascular disease or dyslipidemia. Two hundred and sixty-four patients (134 men/130 women, mean age 43.8+/-14.8/46.0+/-14.9 years) of Lipid Center, University Hospital Olomouc, off hypolipidemic therapy for at least 6 weeks, participated in the study. In multiple regression analysis, adiponectin was independently positively associated with serum HDL-cholesterol (p<0.0001) and sVCAM-1 (p<0.0001), female gender (p<0.0001) and negatively with hs-CRP (p=0.014). Serum concentration of adiponectin and sICAM-1 did not correlate but sICAM-1 was independently, positively associated with sVCAM-1 (p<0.0001) and negatively with markers of insulin resistance and inflammation, namely atherogenic index log[triglycerides/HDL-cholesterol] (p<0.0001), hs-CRP (p<0.001) and HOMA (p<0.05). Positive association of adiponectin with HDL-C and negative association with hs-CRP indicate anti-atherogenic properties of adiponectin. The finding of the positive association of adiponectin with sVCAM-1 in patients at risk is unexpected. We hypothesize that adiponectin may be involved (directly or indirectly) in shedding of ectodomains of VCAM-1 from endothelial surface and in this way down-regulates their effects. This process may be protective in the initial stages of atherosclerosis.

Endothelial and leukocyte adhesion molecules in primary hypertriglyceridemia

Hypertriglyceridemia is known to be associated to functional impairment of the endothelium and, consequently, to higher risk of atherosclerosis. Nevertheless, some crucial steps in the development of the atherosclerotic plaque are still unknown in primary hypertriglyceridemia. The aim of the present study was to explore the expression of soluble and leukocyte-associated cell adhesion molecules in a group of patients with primary hypertriglyceridemia, both including (n=50) and excluding (n=24) subjects with metabolic syndrome, in comparison with control normotriglyceridemic individuals (n=30). Lipid profile, CETP activity, HDL and VLDL chemical composition were evaluated. Soluble (VCAM-1, ICAM-1 and E-selectin) and leukocyte cell adhesion molecules (CD18, CD49d and CD54) were measured by enzyme-linked immunosorbent assay and flow cytometry, respectively. Patients with primary hypertriglyceridemia as compared with control subjects showed significantly higher VCAM-1 (15.6+/-4.5 ng/ml versus 13.9+/-3.8 ng/ml, respectively; p<0.05) and ICAM-1 (16.9+/-3.1 ng/ml versus 15.2+/-3.2 ng/ml, respectively; p<0.05). Regarding leukocyte cell adhesion molecules, significant increases were also detected in monocyte CD18 (398+/-180 versus 332+/-136 arbitrary units, respectively; p<0.05) and CD54 (49+/-14 versus 42+/-12 arbitrary units, respectively; p<0.05), and lymphocyte CD18 (122+/-53 versus 101+/-33 arbitrary units, respectively; p<0.05). ICAM-1 plasma levels, as well as monocyte CD18 and CD54, and lymphocyte CD18 persisted elevated even if patients with metabolic syndrome were discarded among those with hypertriglyceridemia. The increase in circulating and leukocyte cell adhesion molecules in primary hypertriglyceridemic patients would highlight the inflammatory process which is a key event in atherogenesis.

The role of aryl hydrocarbon receptor in the pathogenesis of cardiovascular diseases

Numerous experimental and epidemiological studies have demonstrated that polycyclic aromatic hydrocarbons (PAHs), which are major constituents of cigarette tobacco tar, are strongly involved in the pathogenesis of the cardiovascular diseases (CVDs). Knowing that PAH-induced toxicities are mediated by the activation of a cytosolic receptor, aryl hydrocarbon receptor (AhR), which regulates the expression of a group of xenobiotic metabolizing enzymes (XMEs) such as CYP1A1, CYP1A2, CYP1B1, NQO1, and GSTA1, suggests a direct link between AhR-regulated XMEs and CVDs. Therefore, identifying the localization and expression of the AhR and its regulated XMEs in the cardiovascular system (CVS) is of major importance in understanding their physiological and pathological roles. Generally, it was believed that the levels of AhR-regulated XMEs are lower in the CVS than in the liver; however, it has been shown that similar or even higher levels of expression are demonstrated in the CVS in a tissue- and species-specific manner. Moreover, most, if not all, AhR-regulated XMEs are differentially expressed in most of the CVS, particularly in the endothelium cells, aorta, coronary arteries, and ventricles. Although the exact mechanisms of PAH-mediated cardiotoxicity are not fully understood, several mechanisms are proposed. Generally, induction of CYP1A1, CYP1A2, and CYP1B1 is considered cardiotoxic through generating reactive oxygen species (ROS), DNA adducts, and endogenous arachidonic acid metabolites. However the cardioprotective properties of NQO1 and GSTA1 are mainly attributed to the antioxidant effect by decreasing ROS and increasing the levels of endogenous antioxidants. This review provides a clear understanding of the role of AhR and its regulated XMEs in the pathogenesis of CVDs, in which imbalance in the expression of cardioprotective and cardiotoxic XMEs is the main determinant of PAH-mediated cardiotoxicity.

Soluble P-selectin levels in diabetes mellitus patients with coronary artery disease

Type 2 (non-insulin-dependent) diabetes is associated with a marked increase in the risk of coronary heart disease. Platelets play a significant role in coronary artery disease. Soluble P-selectin is an index of platelets activation. In this study, Soluble P-selectin levels were measured by ELISA in the peripheral blood of 55 diabetic patients with coronary artery disease [21 acute myocardial infarction (AMI), 20 with unstable angina (UA), 14 with stable angina (SA)], 20 patients with diabetes mellitus without coronary artery disease (DM without), and 10 healthy controls. Soluble P-selectin level was significantly higher in patients with AMI (M+/-SD; 239.3+/-13.0 ng/ml), than those with UA (141.5+/-15.2 ng/ml), SA (92.1+/-7.7 ng/ml), DM without (89.8+/-7.1 ng/ml), and healthy control (86.1+/-4.5 ng/ml) (P < 0.001). In patients with US, sP-selectin was found to be significantly elevated as compared to the SA, DM without and control group. sP-selectin was not significantly different in DM without as compared to healthy controls. The sP-selectin levels was correlated to the duration of diabetes mellitus(R=0.33, P=0.03 ). Moreover, sP-selectin level was significantly higher in AMI patients with recurrent anginal attack as compared to that in those with single attack Multivariate analysis revealed that sP-selectin level at presentation had high adverse influence on coronary artery insult compared to healthy LDL cholesterol level, and the degree of hypertension.

IN CONCLUSION

Plasma levels of soluble P-selectin were increased in patients with AMI, and UA compared to patients with SA and normal controls. Measurement of soluble P-selectin may be helpful marker of impending coronary artery insult in diabetic patients.

Markers of endothelial dysfunction in the prediction of coronary artery disease in type 1 diabetes. The Pittsburgh Epidemiology of Diabetes Complications Study

Low-density lipoprotein (LDL) oxidation, the immune response it provokes, and lipoprotein subclasses measured by nuclear magnetic resonance (NMR) spectroscopy have explained some of the enhanced coronary artery disease (CAD) risks in Type 1 diabetes. We examined whether cellular adhesion molecules further improve CAD prediction. Participants were identified from the Epidemiology of Diabetes Complications (EDC) cohort, a 10-year prospective study of childhood-onset Type 1 diabetes. Mean age at baseline was 28 years, and diabetes duration was 19 years. CAD incidence was determined by EDC physician-diagnosed angina, confirmed myocardial infarction (MI), stenosis > or =50%, ischemic ECG, or revascularization. Cases were gender, age, and diabetes duration (+/-3 years) matched with the controls. The samples and risk factors used in the analyses were identified from the earliest exam prior to incidence in the cases. Sixty cases and 72 controls (including 43 pairs) had complete information on all covariates. Cox proportional hazard models with backward elimination and conditional logistic regression (for paired analyses) were conducted. Separate analyses were conducted to examine whether E-selectin related differently to soft (ischemic ECG and angina; n=68) or hard (revascularization, MI, and fatal events; n=37) CAD endpoints. Mean E-selectin concentration was elevated among cases (P=.0009) compared to controls. Adjusting for previously established CAD risk factors, E-selectin remained an independent predictor of CAD (HR=1.07, 95% Cl=1.01-1.15). Multivariable models confirmed the importance of E-selectin as a risk factor of soft (HR=1.13, 95% Cl=1.03-1.24; HRs are per standard deviation increase) but not hard CAD. Study results suggest that E-selectin may enhance CAD prediction beyond traditional risk factors or markers of oxidative stress in Type 1 diabetes.

Evaluation of markers of endothelial damage in cases of young myocardial infarction

The pathogenesis of arterial thrombotic disease involves multiple genetic and environmental factors related to atherosclerosis and thrombosis. The endothelium is a monolayer of polygonal cells that extend continuously over the luminal surface of the entire vasculature. Injury to the endothelium leads to dysfunction. The causes of injury include lipids, immune complexes, microorganisms, smoking, hypertension, aging, diabetes mellitus and trauma. Studies have been done to evaluate the role of different adhesion molecules on the endothelial membrane in the pathogenesis of atherosclerosis. These molecules are intercellular adhesion molecule type-1 (ICAM-1), vascular cell adhesion molecule type-1 (VCAM-1), platelet/endothelial cell adhesion molecule-1 (PECAM-1), soluble P-selectin (sP-selectin) and soluble E-selectin (sE-selectin). One-hundred and twenty patients of myocardial infarction (age below 40 years) were recruited from the out-patients department of Department of Cardiology, KEM Hospital, Mumbai. All the patients were recruited 8-10 weeks after stabilization after MI. We estimated the levels of sP-selectin, sE-selectin, sPECAM-1 and serum homocysteine. Healthy age and sex-matched controls and family controls were also recruited in the present study. The levels of sP-selectin, sE-selectin and sPECAM-1 did not differ significantly in cases as compared to controls (p>0.05). Hyperhomocysteinemia was significantly associated with MI in comparison with controls (p<0.001) with an odds ratio of 6.26 (95% confidence limits 3.11-12.76). Folic acid was able to correct hyperhomocysteinemia in a large majority of the cases. Although the levels of sP-selectin, sE-selectin and sPECAM-1 decreased after folic acid therapy, it was only sE-selectin which was significantly reduced (p<0.05). Thus, folic acid had a dual effect in that it reduced hyperhomocysteinemia and sE-selectin which showed a significant reduction on folate supplementation for 15 days.

Soluble adhesion molecules and marine n-3 fatty acids in patients referred for coronary angiography

OBJECTIVE

To investigate the relationship between soluble cellular adhesion molecules (sCAMs) and the extent of coronary artery disease (CAD) in patients with stable angina pectoris.

METHODS AND RESULTS

Two hundred and ninety-one subjects had fasting levels of circulating intercellular adhesion molecule-1(sICAM-1), vascular cellular adhesion molecule-1 (sVCAM-1), sP-selectin and contents of n-3 polyunsaturated fatty acids (n-3 PUFA) in granulocyte membranes and adipose tissue determined before undergoing elective coronary angiography. Levels of soluble VCAM-1 (983+/-216 versus 893+/-196 ng/l, p<0.001), ICAM-1 (318+/-140 versus 290+/-75 ng/l, p<0.05) and P-selectin (90+/-27 versus 80+/-23 ng/l, p<0.01) were significantly increased in subjects with significant CAD compared to subjects with no significant stenoses. In a linear regression analysis, both sVCAM-1 and sP-selectin, but not sICAM-1, correlated to the presence and the severity of CAD. Both sICAM-1 and sP-selectin were significantly correlated to current smoking status and a history of myocardial infarction. The content of total n-3 PUFA and docosahexaenoic acid in adipose tissue was marginally, but significant positively correlated to VCAM-1.

CONCLUSION

sVCAM-1 and sP-selectin may serve as markers of CAD in patients with stable angina pectoris. Only sVCAM-1 was weakly correlated to n-3 PUFA in adipose tissue.

Angiotensin receptor blockade decreases markers of vascular inflammation

A protective role against atherosclerosis can be attributed to angiotensin converting enzyme inhibitors (ACE-I), since they have been shown to reduce mortality in patients at cardiovascular risk. Since plasma levels of adhesion molecules are considered surrogate markers of endothelial cell activation and atherogenesis, we compared the levels of adhesion molecules after treatment with the ACE-I enalapril or the direct angiotensin- receptor antagonist losartan or placebo. In a randomized, controlled trial, 21 hypercholesterolemic volunteers received 50 mg/d losartan or 20 mg/d enalapril or placebo for twelve weeks. Plasma levels of circulating intercellular adhesion molecule-1 (cICAM-1), vascular adhesion molecule-1 (cVCAM-1), and E-selectin (cE-SEL) were measured by ELISA. Surface expression of ICAM-1 on circulating leukocytes was determined by flow cytometry. Enalapril and losartan but not placebo induced a small but stable decrease of cICAM-1 and cVCAM-1, while cE-SEL and leukocyte expression of ICAM-1 remained unchanged. The lowering of plasma adhesion molecules may indicate an antiatherogenic effect of angiotensin II blockade in hypercholesterolemia. While such preventive effect will have to be proven in clinical trials, our results do not support a preference for either enalapril or losartan with regard to their possible vasoprotective role.

Selectin-P and interleukin-8 plasma levels in coronary heart disease patients

BACKGROUND

Alterations of the immune system are now believed to play crucial role in the pathogenesis of atherosclerosis. The aim of this study was analysis of soluble forms of selectin-P and interleukin-8 levels in patients with different form of coronary heart disease.

MATERIALS AND METHODS

In the study took part 18 patients with stable coronary heart disease, 20 patients with unstable coronary heart disease and 15 healthy persons from control group. Soluble selectin-P and interleukin-8 levels were measured in EDTA plasma with the use of enzyme immunoassay ELISA.

RESULTS

The level of soluble selectin-P was significantly higher in unstable coronary heart disease patients in comparison to the stable coronary heart disease patients (P < or = 0.01) and nonsignificantly higher in comparison to the control group. The level of interleukin-8 were significantly higher in unstable coronary heart disease patients in comparison to the stable coronary heart disease patients (P < or = 0.01) and in comparison to the control group (P < or = 0.02).

CONCLUSION

Our findings suggest that soluble form of selectin-P and interleukin-8 may be useful clinical predictors of unstable coronary heart disease. The assessment of the risk for the development of coronary heart disease requires further serial investigation.

Transcardiac gradient of soluble adhesion molecules predicts progression of coronary artery disease

BACKGROUND

During the development of atherosclerotic lesion, several types of cellular adhesion molecules (CAMs) are overexpressed on the surface of vascular endothelium. Some parts of these membrane proteins are proteolysed and are detected in blood as soluble forms.

AIMS

The purpose of this study is to investigate the relationship between the transcardiac gradient of soluble cellular adhesion molecules (sCAMs) and the clinical characteristics of coronary artery disease (CAD).

METHODS

We studied 46 patients with clinically stable CAD. Serum sCAM levels in both aortic sinus and coronary sinus were measured using enzyme-linked immunosorbent assay, and the transcardiac gradient of sCAMs was calculated. We also evaluated the angiographic severity of CAD, response of coronary artery to acetylcholine (Ach), as well as progression of coronary atherosclerosis over a 6-month period.

RESULTS

The transcardiac gradient of sCAMs did not correlate to the angiographic severity of coronary atherosclerosis. The transcardiac gradient of sVCAM-1 was significantly higher in patients with vasoconstrictive response to Ach than patients without vasoconstrictive response to Ach (191.5+/-98.2 vs. -9.2+/-14.1 ng/ml, P<0.05). Furthermore, patients who exhibited progression of coronary atherosclerosis had a higher transcardiac gradient of sVCAM-1 at the initial study than patients without progression (47.8+/-24.5 vs. -6.4+/-12.3 ng/ml, P<0.05).

CONCLUSIONS

An elevated transcardiac gradient of sVCAM-1 may represent the persistent activation of coronary artery that is accompanied by endothelial dysfunction, and may be a predictive index of progression of coronary atherosclerosis. Measurement of coronary circulating sVCAM-1 could provide important functional and predictive information about atherosclerosis.

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

The recruitment of circulating leukocytes to atherosclerotic sites is mediated by a family of adhesion molecules. The objective of the present study was to evaluate the relationship between circulating adhesion molecule levels in the coronary circulation and the severity of coronary atherosclerosis in patients with stable coronary artery disease. The subjects were 79 patients undergoing coronary angiography. According to the severity of coronary atherosclerosis as assessed by the Gensini Score (GS) of the left coronary artery, they were classified into three groups: group C (no organic stenosis, score 0, n = 14), group M (mild organic stenosis, score 1-13, n = 39) and group S (severe organic stenosis, score > or = 14, n = 26). Blood samples were taken from the aorta (Ao) and coronary sinus (CS), and plasma levels of soluble E-selectin (sE-selectin) and soluble intercellular adhesion molecule-1 (sICAM-1) were measured by enzyme-linked immunosorbent assay. These levels were then compared between groups. There were no significant differences in plasma sICAM-1 levels in the Ao or CS between the three groups. The difference in sICAM-1 levels between the CS and Ao (CS-Ao) also showed no significant difference. Plasma sE-selectin levels in both the Ao and CS were significantly higher in group S than in groups C and M (p < 0.05), but there were no significant differences in CS-Ao. There was a weak but significant correlation between the plasma levels of these adhesion molecules and the number of coronary risk factors present. Multivariate analysis showed that the number of coronary risk factors was the only positive predictor (p = 0.0048) of the GS; there was no association between the plasma level of either adhesion molecule and the GS. In patients with stable coronary artery disease, sICAM-1 plasma levels do not indicate the severity of coronary atherosclerosis, while sE-selectin plasma levels appear to reflect the severity of systemic rather than coronary atherosclerosis.

Association between P-selectin gene polymorphisms and soluble P-selectin levels and their relation to coronary artery disease

P-selectin is a cellular adhesion molecule that mediates the interaction of activated endothelial cells or platelets with leukocytes. Increased levels of soluble P-selectin have been reported in various cardiovascular disorders. We measured serum soluble P-selectin levels as well as 3 polymorphisms of the P-selectin gene (C-2123G, A-1969G, and Thr715Pro) in a large cohort of patients with documented coronary artery disease (n=869) and a healthy control group (n=334). The 3 P-selectin polymorphisms were strongly associated with P-selectin levels and altogether explained 7.3% and 18.6% of the P-selectin variability in patients and controls, respectively. Genotype distributions did not significantly differ between patients and controls. P-selectin levels were increased in patients younger than 55 years of age compared with controls (135.2 vs 114.3 ng/mL, P<0.01). On the contrary, patients older than 65 years of age had significantly lower P-selectin levels than did controls (121.5 vs 134.7 ng/mL, P<0.02). In intermediate age groups, P-selectin levels did not significantly differ between the 2 groups. In conclusion, this study revealed a strong association between P-selectin gene polymorphisms and serum P-selectin levels and a complex age-dependent relation between soluble P-selectin levels and coronary artery disease, which suggests that this molecule might have different roles in the atherothrombotic process.

Adhesion molecules and atherogenesis

Atherosclerosis is an inflammatory disease of the vessel wall characterized by monocyte infiltration in response to pro-atherogenic factors such as oxidized lipids. Recently, the role of specific adhesion molecules in this process has been explored. The endothelium overlying atherosclerotic lesions expresses P-selectin and the shoulder regions express vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), which is also expressed on endothelium in regions not prone to plaque development. Serum levels of soluble P-selectin, ICAM-1 and VCAM-1 are elevated in patients with angina pectoris or peripheral atherosclerotic disease. Reconstituted in vitro systems using monocytes on cytokine-activated endothelial cells under shear flow suggested the involvement of P-selectin, L-selectin, VCAM-1, its ligand, VLA-4 integrin and CD18 integrins. Studies of monocyte adhesion in isolated perfused carotid arteries harvested from atherosclerotic (apoE-/-) mice show a predominant involvement of P-selectin and its ligand P-selectin glycoprotein-1 (PSGL-1) in rolling and of VLA-4 and VCAM-1 in firm adhesion. Consistent with these findings, apoE-/- mice that are also deficient for P-selectin show significantly reduced atherosclerotic lesion sizes and are almost completely protected from neointimal growth after vascular injury. Milder effects are also seen in the low-density lipoprotein (LDL) receptor deficient (LDLR-/-) mouse. In a high cholesterol/cholate model, a role of ICAM-1 and CD18 integrins was also shown, but this awaits confirmation in more physiologic models. Transient blockade of the VLA-4/VCAM-1 adhesion pathway by antibodies or peptides in apoE-/- or LDLR-/- mice reduced monocyte and lipid accumulation in lesions. These data suggest that P-selectin, PSGL-1, VLA-4 and VCAM-1 are the most important adhesion molecules involved in monocyte recruitment to atherosclerotic lesions.

The D allele of the angiotensin-converting enzyme gene and reperfusion-induced ventricular arrhythmias in patients with acute myocardial infarction

The renin-angiotensin system may play a pivotal role in reperfusion ventricular arrhythmias (RVA). The purpose of this study was to investigate the association between angiotensin-converting enzyme (ACE) gene polymorphism and RVA in patients with acute myocardial infarction (AMI) in a case-control study. Patients who had undergone successful coronary intervention for AMI were enrolled (n= 127, male/female: 97/30, mean age, 62.6 years). The incidence of RVA was continuously monitored by ECG at a coronary care unit. The severity of ventricular arrhythmias was evaluated in terms of the Lown's grade and patients with a high risk of ventricular arrhythmias that may cause sudden cardiac death (Lown's grade > or =2) within 5 h of coronary intervention were defined as cases (n=59), and otherwise as controls (n=68). A receiver operating characteristic curve was used to determine the discriminatory ability of continuous variables and to produce dummy variables for use in a logistic regression analysis. Cases had a significantly higher body mass index, higher maximal levels of serum creatine kinase, and a shorter time preceding coronary intervention than controls. The severity of coronary atherosclerosis was similar between the 2 groups. The frequency distribution of ACE genotypes in cases differed from that in controls (II/ID/DD: 22.0%/52.6%/25.4% vs 44.1%/41.4%/14.7%, p<0.05, by the Mantel-Haenzel chi-square test). The ACE-D allele had additive and dominant effects with regard to the occurrence of significant ventricular arrhythmias after adjusting for other risk factors. The ACE-D allele may play a pivotal role in sudden cardiac death in patients with AMI.

Functions of selectins

The selectins are cell surface lectins that have evolved to mediate the adhesion of white blood cells to endothelial cells and platelets under flow. They recognize fucosylated, sialylated and in some cases sulfated ligands expressed on scaffold glycoproteins serving as functional counter-receptors. Selectins are regulated at the transcriptional level, through proteolytic processing, through cellular sorting, and through regulated expression of glycosyl-transferases responsible for the formation of functional ligands. The selectins are physiologically important in inflammation, lymphocyte homing, immunological responses, and homing of bone marrow stem cells. They play a role in atherosclerosis, ischemia-reperfusion injury, inflammatory diseases, and metastatic spreading of some cancers.

Soluble VCAM-1 and E-selectin, but not ICAM-1 discriminate endothelial injury in patients with documented coronary artery disease

It has been shown that endothelial cell adhesion molecules play an important role in the development of coronary atherosclerosis and inflammatory disease. We sought to test whether soluble vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and E-selectin are increased in patients with documented coronary artery disease (CAD). Plasma levels of VCAM-1, ICAM-1 and E-selectin were measured in 40 patients with documented CAD, 20 subjects with angiographically documented normal coronary arteries, and 14 healthy volunteers. Patients with documented CAD exhibited significant elevation of VCAM-1 (535 +/- 227.1 ng/ml, p = 0.0001), E-selectin (69.4 +/- 29.4 ng/ml, p = 0.006), but not ICAM-1 (320.5 +/- 65.1 ng/ml, p = 0.9) concentrations as compared to subjects with normal coronary arteries (252.3 +/- 79.8, 49.7 +/- 22.0 and 311.4 +/- 40.2 ng/ml), and healthy controls (110.0 +/- 17.7, 29.0 +/- 2.0 and 237.5 +/- 46.5 ng/ml), respectively. Soluble markers of endothelial injury are not uniformly increased in patients with documented CAD as compared to those with normal coronary arteries and healthy controls. However, VCAM-1 and E-selectin, but not ICAM-1 could identify endothelial injury in such patients.

Hyperinsulinemic hypoalphalipoproteinemia as a new indicator for coronary heart disease

OBJECTIVES

The purpose of this study was to investigate the association among insulin resistance, high density lipoprotein cholesterol (HDL-C) and coronary heart disease (CHD), and to test the hypothesis that HDL-C may ameliorate the adverse effects of insulin.

BACKGROUND

Serum low HDL-C (hypoalphalipoproteinemia) and hyperinsulinemia are independent predictors for CHD, but a strong negative correlation exists between them, as in patients with syndrome X.

METHODS

Fifty-four pairs of cases (M/F: 49/5), defined as patients with angiographically proved CHD, and control subjects (M/F: 49/5) matched with cases with regard to gender and age were included. Insulin resistance was assessed by the homeostasis model assessment (HOMA).

RESULTS

Cases had increased HOMA insulin resistance and lower serum levels of HDL-C than controls. A receiver operating characteristic (ROC) curve analysis indicated that HDL-C and insulin resistance were significant discriminators of CHD (area under ROC curve: 0.72 and 0.69, respectively). The interaction between HDL-C and the association of insulin resistance with CHD was significant: subjects with hyperinsulinemia and high HDL-C had no increased risk of CHD. Multivariate conditional logistic regression analysis showed that hyperinsulinemic hypoalphalipoproteinemia was a stronger indicator for CHD than either HDL-C or insulin resistance alone (-2 log likelihood: 19.0 vs. 12.6 or 15.7).

CONCLUSIONS

Hyperinsulinemic hypoalphalipoproteinemia was a more potent indicator for CHD than either insulin resistance or low serum HDL-C levels alone, and the adverse effects of hyperinsulinemia seem to be ameliorated by high HDL-C levels.

Insulin resistance and angiographical characteristics of coronary atherosclerosis

Insulin resistance (IR) is frequently observed in patients with coronary heart disease (CHD). The relationship between IR and the angiographical characteristics of coronary atherosclerosis were investigated in 66 patients with coronary artery lesions. Insulin resistance was assessed by a 75-g oral glucose tolerance test and homeostasis model assessment (HOMA). The angiographical characteristics of coronary atherosclerosis (i.e., the severity of CHD) were defined by both Gensini's score (GS) (a higher degree of coronary artery stenosis or a proximal lesion was assigned a higher score than a distal lesion) and the number of significantly stenosed vessels. When GS was examined as a categorical variable classified by tertile values (Group A, n = 22: 1< or =GS< or =14; Group B, n = 22: 15< or =GS< or =32; and Group C, n = 22: 33< or =GS), patients with a high GS (Group C) had significantly (p<0.05) higher values of fasting plasma insulin, insulin response, and HOMA IR than patients with a low GS (Group A) (12.6+/-1.2 microU/ml vs. 6.9+/-1.2 microU/ml, 122.2+/-11.9 microU ml(-1) h(-1) vs. 72.9+/-12.9 microU ml(-1) h(-1), and 2.9+/-0.3 vs. 1.5+/-0.3, respectively). The values in Group B patients (9.4+/-1.2,microU/mI, 108.5+/-12.5 microU ml(-1) h(-1), and 2.1+/-0.3, respectively) were intermediate between those in Groups A and C. The area of insulin/area of glucose ratio was significantly (p<0.05) higher in Groups B and C than in Group A (0.54+/-0.06 microU/mg, 0.54+/-0.06 microU/mg, and 0.32+/-0.06 microU/mg, respectively). However, no significant differences were observed in variables of glucose tolerance, serum lipid, lipoproteins, fibrinogen, uric acid, and blood pressure among the 3 groups. Significant (p<0.05) positive associations were found between GS, the number of diseased coronary arteries, and fasting immunoreactive insulin, insulin response, the area of insulin/area of glucose ratio and HOMA IR by logistic regression analysis. After adjusting for the number of diseased coronary arteries, the association between GS and IR was not significant, suggesting that IR contributed to the severity of coronary atherosclerosis but not to the distribution of lesions. In conclusion, IR was associated with the severity of CHD as measured by both Gensini's score and the number of diseased coronary arteries, and increased the risk of CHD regardless of the location of the lesions.