Platelet and leukocyte adhesion and activation in unstable angina and post-PTCA

SELL and GUCY1A1 Gene Polymorphisms in Patients with Unstable Angina

Acute ischaemia is mostly caused by the rupture of an unstable atherosclerotic plaque in a coronary artery, resulting in platelet accumulation and thrombus formation, which closes the lumen of the coronary vessel. Many different factors can cause atherosclerotic plaques to occlude the lumen of a coronary artery, including factors that increase vascular inflammation and blood platelet aggregation, as well as genetic factors. L-selectin is an adhesion molecule encoded by the human SELL gene, playing an important role in leukocyte adhesion to the endothelium and the development of inflammation. Guanylate cyclase 1 soluble subunit alpha 1 (GUCY1A1) is a gene that affects vasoreactivity and platelet function, thereby influencing thrombotic processes and the risk of developing thrombotic lesions in the coronary vessels. In SELL and GUCY1A1 genes, several polymorphisms have been detected, which may affect gene expression. The aim of our study was to assess the association between the SELL rs2205849 and rs2229569 and GUCY1A1 rs7692387 polymorphisms with the risk of acute coronary syndromes in the form of unstable angina pectoris, and the association between these polymorphisms and selected clinical parameters affecting the risk of developing ischemic heart disease. The study included 232 patients with unstable angina. The diagnosis of unstable angina was achieved by a typical clinical presentation and confirmation of significant coronary artery lumen stenosis (>70%) during coronary angiography. There were no statistically significant differences in GUCY1A1 rs7692387 and SELL rs2205849 and rs2229569 polymorphism distribution between the total study and the control groups. However, when only analysing patients over 55 years of age, we found a decreased frequency of the GUCY1A1 rs7692387AA genotype (AA vs. GA + GG, OR: 0.07; 95% CI: 0.01−0.78) and an increased frequency of the SELL rs2205849 CC genotype (CC vs. TC + TT p = 0.022) and SELL rs2229569 AA genotype (AA vs. GA + GG p = 0.022) in patients with unstable angina. Our results suggest that the SELL rs2205849 and rs2229569 and GUCY1A1 rs7692387 polymorphisms are not risk factors for unstable angina in the Polish population. The GUCY1A1 rs7692387 polymorphism may increase the risk of unstable angina in patients younger than 55 years, while the SELL polymorphisms rs2205849 and rs2229569 may increase the risk of unstable angina in patients older than 55 years in the Polish population.

The role of monocyte phenotype switching in peri-procedural myocardial injury and its involvement in statin therapy

Peri-procedural myocardial injury, which is associated with worse long-term clinical outcome, is a common complication related to inflammatory pathogenetic mechanisms. Monocytes and macrophages play key roles in the initiation and progression of atherosclerosis. Recent studies have demonstrated that monocytes in human peripheral blood are heterogeneous, including CD14⁺CD16⁻ monocytes and CD14⁺CD16⁺ monocytes. Several lines of evidence suggested that CD14⁺CD16⁺ monocytes might contribute to the accelerated atherosclerosis. In view of the heightened appreciation of the heterogeneity of circulating monocytes, we hypothesized that an up-shifting subset of CD14⁺CD16⁺ monocytes might be induced by percutaneous coronary intervention (PCI), which subsequently leads to peri-procedural myocardial injury. Moreover, statins loading before PCI could exert anti-inflammatory effects partly by modulating monocyte phenotype and thus prevent peri-procedural myocardial injury.

Expression of inflammatory and apoptosis factors following coronary stent implantation in coronary heart disease patients

We investigated the changes in characteristics of neutrophil CD11b, monocyte CD11b, platelet CD62P, endothelin (ET), and neutrophil CD178 in patients with coronary heart disease (CHD) before and after primary coronary stenting. A total of 41 patients with CHD who underwent coronary stenting and 40 control subjects were enrolled in the study. In CHD patients, peripheral blood samples were taken 24 h before and 30 min, 24 h, and 72 h after successful coronary stenting. All markers were significantly elevated in patients with CHD compared with controls (P<0.05). Time-course studies revealed that the expressions of neutrophil CD11b, monocyte CD11b, platelet CD62P, and ET were lower at 30 min post-operation (PO) compared with that at 24 h before operation (BO) (P<0.05). All levels significantly increased from 30 min PO to 24 h PO (P<0.05) and decreased thereafter until 72 h PO (P>0.05). Time course changes in neutrophil CD11b levels after coronary stenting were significantly higher in patients with unstable angina pectoris than in patients with stable angina pectoris (P<0.05). CD11b levels were related to CD62P in patients with CHD (P<0.05). Neutrophil CD11b and monocyte CD11b levels were significantly increased in patients with CHD who underwent coronary stenting compared with controls (P<0.05). Results show that CD11b levels increased, meanwhile, the levels of CD62P and ET increased in CHD patients after coronary stenting. In addition, neutrophil CD178 levels of apoptosis factor in patients, which is important for regression of inflammation, remained high for a period of time after coronary stenting.

Skeletonized coronary arteries: pathophysiological and clinical aspects of vascular calcification

The role of calcification in coronary artery disease is gaining importance, both in research studies and in clinical application. Calcified plaque has long been considered to be the most important atherosclerotic plaque within the arterial tree and frequently presents a challenge for percutaneous intervention. Current investigations have shown that plaque calcification has a dynamic course that is closely related to the magnitude of vascular inflammation. Numerous inflammatory factors synthesized during the early stages of atherosclerosis induce the expression and activation of osteoblast-like cells localized in the arterial wall that produce calcium. There is no doubt that the role of these factors in calcification associated with coronary artery disease could be a crucial strategic point in prevention and treatment. A number of diagnostic imaging methods have been developed in recent years, but their performance needs to be improved. In this context, we undertook an update on coronary calcification, focusing on physiopathology, clinical implications, and imaging techniques.

Monocyte functional responsiveness after PSGL-1-mediated platelet adhesion is dependent on platelet activation status

OBJECTIVE

Acute coronary diseases are characterized by elevated levels of circulating platelet-leukocyte complexes, raising the possibility that proinflammatory processes might be initiated in leukocytes after platelet adhesion. Here we examined the mechanism of platelet binding to polymorphonuclear leukocytes, monocytes, and monocyte subsets and investigated the potential functional consequences of monocyte binding to minimally activated or thrombin-activated platelets.

METHODS AND RESULTS

In this article, we describe key differences in terms of stability of PSGL-1-mediated interaction of platelets with monocytes and polymorphonuclear leukocytes and a small but significant difference in platelet binding to monocyte subsets (CD14(high) and CD14(low)/HLA-DR(high)). We also report differential effects of platelet binding on monocyte functional responses between minimally and thrombin-activated platelets. In particular, monocyte CD11b expression and release of proinflammatory cytokines, like interleukin 1beta and tumor necrosis factor alpha, were significantly upregulated on adhesion of stimulated platelets, whereas unstimulated platelets had no effect. Moreover, binding of unstimulated, but not of thrombin-activated, platelets to monocytes had no impact on NF-kappaB activity, monocyte migration, and induction of apoptosis in the absence of survival factors.

CONCLUSIONS

Our data suggest that in the absence of overt activation, PSGL-1-P-selectin-dependent platelet binding to monocytes represents a normal physiological process with little impact on the potential of monocytes to cause vascular injury.

Circulating platelet and neutrophil activation correlates with the clinical course of unstable angina

Recent studies have suggested important roles of inflammation in the pathophysiology of unstable angina (UA). We investigated whether activation of the circulating platelets and neutrophils were implicated in inflammatory reactions associated with unstable angina Expressions of platelet P-selectin and neutrophil CD11b, and neutrophil-platelet aggregates were evaluated by flow cytometry in anticoagulated peripheral venous blood from 71 patients with UA and 22 patients with stable angina (SA). Expressions of platelet P-selectin and neutrophil CD11b, and neutrophil-platelet aggregates on the admission day were all significantly higher in 71 patients with UA than 22 with SA (median, mean fluorescence intensity [MFI]: 7.00 vs 4.51, P < 0.01, 64.68 vs 47.75, P = 0.0007; and % of 10 000 neutrophils: 7.84 vs 3.40, P = 0.0001, respectively). These three parameters in 43 patients with UA were significantly decreased (MFI: 4.23, P = 0.003, 50.82, P = 0.0003; and % of 10 000 neutrophils: 5.04, P = 0.0001, respectively) 7 days after the first measurement. These results indicate that circulating activated platelets and neutrophils are more strongly implicated in the acute phase of UA. These findings also suggest that thrombus formation after rupture of atherosclerotic plaques as well as plaque formation involves inflammatory reactions.

Genomic changes in regenerated porcine coronary arterial endothelial cells

OBJECTIVE

Genomic changes were defined in cultures of regenerated porcine coronary endothelial cells to explain the alterations that underlie their dysfunction.

METHODS AND RESULTS

Regeneration of the endothelium was triggered in vivo by endothelial balloon denudation. After 28 days, both left circumflex (native cells) and left anterior descending (regenerated cells) coronary arteries were dissected, their endothelial cells harvested, and primary cultures established. The basal cyclic GMP production was reduced in regenerated cells without significant reduction in the response to bradykinin and A23187. The mRNA expression levels in both native and regenerated cells were measured by microarray and RT-PCR. The comparison revealed genomic changes related to vasomotor control (cyclooxygenase-1, angiotensin II receptor), coagulation (F2 and TFPI), oxidative stress (Mn SOD, GPX3, and GSR), lipid metabolism (PLA2 and HPGD), and extracellular matrix (MMPs). A-FABP and MMP7 were induced by regeneration. RT-PCR revealed upregulation of A-FABP and downregulation of eNOS and TR. The differential gene expression profiles were confirmed at the protein level by Western blotting for eNOS, F2, Mn SOD, MMP7, and TR.

CONCLUSIONS

Cultures from regenerated coronary endothelial cells exhibit genomic changes explaining endothelial dysfunction and suggesting facilitation of coagulation, lipid peroxidation, and extracellular matrix remodeling.

Expression of monocyte and lymphocyte adhesion molecules is increased in isolated coronary artery ectasia

BACKGROUND

Coronary artery ectasia is defined as localized or diffuse dilation of the coronary arteries exceeding the 1.5-fold of normal adjacent segment. Scarce data are available about the role of inflammation in coronary artery ectasia. In the present study, we aimed to evaluate the expression of CD11b and CD45 adhesion molecules in peripheral blood granulocytes, monocytes and lymphocytes from the patients with coronary artery ectasia as possible indicators of inflammation.

METHOD

The study consisted of 14 patients who had angiographically normal coronary arteries with coronary artery ectasia and 13 age and sex-matched controls without coronary artery ectasia. Cell surface adhesion molecules were detected by direct immunofluorescence evaluated by flow cytometry using monoclonal antibodies tagged with fluorescent markers. Venous blood samples were taken after coronary angiography.

RESULTS

Mean fluorescence intensity of CD45 (33.8+/-3.1 vs. 13.0+/-0.7, P<0.001) and CD11b (39.1+/-13.5 vs. 19.5+/-1.32, P<0.001) on the monocyte surface of patients with coronary artery ectasia were higher than those of controls. Similarly in patients with coronary artery ectasia, the expression of CD11b (7.5+/-0.61 vs. 5.6+/-0.2, P=0.009) and CD45 (47.5+/-3.6 vs. 36.2+/-2.5, P=0.02) on lymphocytes was also significantly higher than those of controls.

CONCLUSION

Increased levels of cellular adhesion molecules in patients with coronary artery ectasia may be an indicator of endothelial activation and inflammation and are likely to be in the causal pathway leading to coronary artery ectasia.

Enhanced inflammatory response following coronary stent implantation in stable angina patients

BACKGROUND

Percutaneous coronary intervention (PCI) is associated with an increase in inflammatory activity. However, little is known about the association between the inflammatory response post-PCI and plaque morphology. The objective of this study was to characterize the inflammatory response following coronary stent implantation (CSI) of stable atherosclerotic plaques, according to plaque morphology.

METHODS

The study population consisted of 62 patients with stable angina that had an elective indication of CSI. Immediately before CSI, the patients underwent intravascular ultrasound (IVUS) for determination of the predominant plaque morphology of the target lesion: calcified (C, n=15), fibrocalcified (FC, n=16), fibrolipidic (FL, n=16), or lipidic (L, n=15). Angiographic lesion types were also determined. Coronary sinus samples were collected at baseline (BL) and 15 min after CSI for measuring inflammatory mediators (IM): interleukin-6 (IL-6, in pg/ml), tumoral necrosis factor-alpha (TNF, in pg/ml), interferon-gamma (IFN, in IU/ml), and neopterin (N, in ng/ml).

RESULTS

BL IL-6, TNF, IFN, and N were, respectively, for C plaques (mean+/-S.D.): 1.3+/-3.0, 8.0+/-3.5, 0.1+/-0.2, and 3.2+/-0.8; for FC plaques: 6.7+/-3.3, 1.9+/-2.0, 0.1+/-0.1, and 3.8+/-2.0; for FL plaques: 0.7+/-0.9, 8.7+/-4.3, 0.1+/-0.2, and 4.0+/-2.4; and, for L plaques: 1.9+/-2.8, 0.9+/-1.4, 0.0+/-0.1, and 5.2+/-3.3. After 15 min of CSI, percentual changes of IL-6, TNF, IFN, and N, respectively, were for C plaques: 43.8+/-19.6%, 7.7+/-5.5%, -7.5+/-5.3%, and -20.0+/-11.2%; for FC plaques: 7.7+/-5.5%, 168.4+/-56.9%, 311.1+/-159.9%, and 0%; for FL plaques: 147.5+/-16.1%*, 714.3+/-34.4%*, 116.1+/-9.9%*, and 3000.0+/-230.0%*; and, for L plaques: 147.7+/-14.4%*, 140.3+/-15.0%*, 131.6+/-11.9%*, and 2300.0+/-25.9%*. Moreover, B1 (n=28) and B2 (n=32) predominated and resulted in significant changes only for IL-6 and IFN, respectively. *P<0.05: 15 min vs BL.

CONCLUSIONS

These data suggest that stable angina patients with predominant lipidic (L and FL) plaques present a greater inflammatory response after CSI in than those with predominant calcified (C and FC) plaques.