Elena Vasilieva

Activation of T Lymphocytes in Atherosclerotic Plaques

Objective—To decipher the immunologic mechanisms of plaque maturation and rupture, it is necessary to analyze the phenotypes and distribution of individual lymphocytes that migrate to the plaques, as well as their activation at different stages of plaque formation. Methods and Results—We developed a protocol to isolate plaque-residing immune cells and analyze their status using polychromatic flow cytometry. We found that the composition and phenotype of T lymphocytes in the plaques differs from that in blood. CD4 and, in particular, CD8+ T cells in plaques are highly activated; the fraction of CD8 T cells coexpressing CD25 and human leukocyte antigen-D related in plaques was 6 times as large as in blood. Conclusion—The first flow-cytoanalysis of individual T cells in atherosclerotic plaques indicates that plaques represent a separate immunologic compartment from blood with lymphocytes characterized by a high level of T-cell activation, which is compatible with the presence of antigen(s) that trigger infiltration activation of these cells. The ability to isolate and characterize these cells may lead to the identification of such antigens.

Remote Ischemic Preconditioning and Endothelial Function in Patients with Acute Myocardial Infarction and Primary PCI

BACKGROUND Remote ischemic preconditioning by transient limb ischemia reduces myocardial ischemia-reperfusion injury in patients undergoing percutaneous coronary intervention. The aim of the study we report here was to assess the effect of remote ischemic preconditioning on endothelial function in patients with acute myocardial infarction who underwent primary percutaneous coronary intervention. METHODS Forty-eight patients with acute myocardial infarction were enrolled. All participants were randomly divided into 2 groups. In Group I (n = 23), remote ischemic preconditioning was performed before primary percutaneous coronary intervention (intermittent arm ischemia-reperfusion through 4 cycles of 5-minute inflation and 5-minute deflation of a blood-pressure cuff to 200 mm Hg). In Group II (n = 25), standard percutaneous coronary intervention without preconditioning was performed. We assessed endothelial function using the flow-mediated dilation test on baseline, then within 1-3 hours after percutaneous coronary intervention, and again on days 2 and 7 after percutaneous coronary intervention. RESULTS The brachial artery flow-mediated dilation results were significantly higher on the first day after primary percutaneous coronary intervention in the preconditioning group (Group I) than in the control group (Group II) (12.1% vs 0.0%, P = .03, and 11.1% vs 6.3%, P = .016, respectively), and this difference remained on the seventh day (12.3% vs 7.4%, P = .0005, respectively). CONCLUSION We demonstrated for the first time that remote ischemic preconditioning before primary percutaneous coronary intervention significantly improves endothelial function in patients with acute myocardial infarction, and this effect remains constant for at least a week. We suppose that the improvement of endothelial function may be one of the possible explanations of the effect of remote ischemic preconditioning.

Activated platelet chemiluminescence and presence of CD45+ platelets in patients with acute myocardial infarction

Abstract It has been found that in 15% of acute myocardial infarction patients’ platelets generate reactive oxygen species that can be detected with luminol-enhanced chemiluminescence of platelet-rich plasma within 8–10 days after acute myocardial infarction. This increase in generate reactive oxygen species production coincides with the emergence of CD45+ platelets. The ability of platelets to carry surface leukocyte antigen implies their participation in exchange of specific proteins in the course of acute myocardial infarction. Future studies of CD45+ platelets in peripheral blood of acute myocardial infarction patients in association with generate reactive oxygen species production may provide a new insight into the complex mechanisms of cell–cell interactions associated with acute myocardial infarction.

Brachial Artery Flow-mediated Dilation in Patients with Tako-Tsubo Cardiomyopathy

BACKGROUND Tako-Tsubo cardiomyopathy (TTC) is a heart syndrome associated with transient myocardial contractile dysfunction. The pathogenesis of TTC remains unclear. The purpose of this study was to investigate brachial artery flow-mediated dilation (FMD) in patients with TTC. METHODS The results of FMD tests of 4 women with TTC were compared with the results from 18 women with ST-elevation acute myocardial infarction (STEMI) and from 26 healthy female volunteers. FMD tests in all patients were performed within 24 hours of admission and again at 1-3 weeks as a follow-up. RESULTS The FMD levels were significantly lower at the acute phase in patients with TTC than in patients with STEMI and in healthy volunteers (P <.01). After 1-3 weeks, the FMD test results of patients with TTC had greatly increased, and no significant differences were found between these results and the results from patients with STEMI (P >.05). Also, there were no significant differences in the FMD test results between the group of patients with TTC and the group of healthy volunteers (P >.05). CONCLUSIONS There is a pronounced and reversible endothelial dysfunction in patients with TTC, which can impair myocardial perfusion.

Cytomegalovirus‐Productive Infection Is Associated With Acute Coronary Syndrome

Background Although an association between human herpesvirus (HHV) infection and atherosclerosis has been suggested, the data supporting such an association are controversial and, in most cases, are based on serological evidence or on the presence of cell‐associated HHV DNA, which do not report about actual viral replication. We quantified the DNA of all 8 types of HHVs in plasma, in which their presence is evidence of viral replication. Methods and Results Using quantitative real‐time polymerase chain reaction, we evaluated the presence of HHV DNA in blood samples obtained at the time of hospitalization from 71 patients with acute coronary syndrome, 26 patients with stable coronary artery disease, and 53 healthy volunteers and in atherosclerotic plaques of 22 patients with peripheral artery disease who underwent endarterectomy. HHV‐5 (cytomegalovirus [CMV]) was the only HHV with a level that was higher in acute coronary syndrome patients than in the control group and that correlated with the level of high‐sensitivity C‐reactive protein. The numbers of effector memory T cells positively correlated with the numbers of CMV genome copies in carotid arteries plaques, whereas the numbers of central memory T cells negatively correlated with CMV copy numbers. Conclusions Of all HHV levels, only CMV was higher in patients with stable coronary artery disease and acute coronary syndrome than in the healthy group, and its load correlated with the level of high‐sensitivity C‐reactive protein. The level of CMV in atherosclerotic plaques correlated with the state of immunoactivation of lymphocytes in plaques, suggesting that the reactivation of CMV may contribute to the immune activation associated with the progression of atherosclerosis.

Aspirin can stimulate luminol-enhanced chemiluminescence of activated platelets

A preliminary investigation was conducted into the influence of aspirin on the luminol-enhanced chemiluminiscence of platelets stimulated with platelet-activating factor (PAF). Ten coronary artery disease patients and six volunteers without coronary artery disease were included in the study. All the patients received aspirin (daily dose, 100 mg) for at least 10 days before in vitro experiments. Luminol-enhanced luminescence of platelet-rich plasma samples mixed with a PAF solution was measured. After stimulation of platelets with PAF, we did not find a luminol-enhanced chemiluminescent response either in the non-coronary artery disease volunteers or in eight out of the 10 coronary artery disease patients examined. However, in samples from two patients where platelets were stimulated with PAF reactive oxygen species were formed. This ability was expressed as an intensive luminol-enhanced luminescence of activated platelets. Such a reaction was observed against the background of the administration of aspirin. The addition of aspirin to a test tube considerably enhanced the intensity of chemiluminescence. In one case, the cancellation of aspirin was accompanied by diminution of the intensity of luminol-enhanced chemiluminescence of platelets. The clinical significance of this phenomenon is unknown.

Total occlusion of the infarct-related coronary artery correlates with brachial artery flow-mediated dilation in patients with ST-elevation myocardial infarction

Background: Occlusion of the coronary artery is the main cause of ST-elevation myocardial infarction (STEMI). In some patients, it is followed by early spontaneous thrombolysis. In this study, we tried to determine whether spontaneous thrombolysis in the infarct-related artery (IRA) correlates with the state of the endothelium, which we assessed using the brachial artery flow-mediated dilation (FMD) test. Methods: 52 patients with STEMI were included in the study. Based on the results of coronary angiography performed during the first three days of STEMI, the patients were divided into two groups: Group I (n=33), consisting of patients with remaining total occlusion of the IRA, and Group II (n=19), consisting of patients with spontaneous thrombolysis. We assessed the endothelial function, using the brachial artery FMD test. Results: In Group I, during the first three days of STEMI, brachial artery FMD results were significantly lower than those in Group II: 5.41± (3.23–7.41)% versus 10.81±(8.00–14.89)%, respectively; P=0.000036. After 7–14 days, this difference disappeared because of significant elevation of the FMD levels in the first group. Group I was characterized by higher levels of high sensitive C-reactive protein (CRP), cholesterol, and cholesterol-LDL and lower usage of angiotensin-converting enzyme (ACE) inhibitors before STEMI. Conclusion: The data presented above reveal that spontaneous coronary thrombolysis in patients with acute STEMI is associated with a preserved endothelium-dependent vasodilator response in the brachial artery. It can depend on the levels of hs-CRP, of fasting glucose, and of ACE-inhibitors from previous treatment.

The antiplatelet effect of atorvastatin in patients with acute coronary syndrome depends on the hs-CRP level.

Background: In data we published earlier, there is a correlation between platelet aggregation in patients with acute coronary syndrome (ACS) who are receiving aspirin and elevated hsCRP-level. We suggested that antiplatelet action of statins, which are known to lower hsCRP-levels, could be especially pronounced in patients with high levels of hsCRP. Methods and results: 54 patients with ACS without ST-segment elevation were included in this study. All patients received aspirin 160–325 mg daily. In addition to aspirin, some patients received atorvastatin 40–80 mg/d (n=19) or 300mg of clopidogrel followed by 75mg/d (n=15). HsCRP-levels and ADP-induced platelet aggregation were assessed on the first and on the eight days of treatment. Patients were divided into subgroups according to initial hsCRP-levels and treatment. In atorvastatin/high-CRP subgroup, the level of aggregation was about three times lower after eight days than it was on the first day. In contrast, in atorvastatin/low-CRP subgroup the level of platelet aggregation did not change during the same period. The effect of clopidogrel did not depend on hsCRP-level. In control group (patients treated with aspirin alone), platelet aggregation did not change with time. Conclusion: There is a correlation between antiplatelet effect of atorvastatin and initial hsCRP-level. The antiplatelet effect of clopidogrel does not depend on hsCRP-level.

Monocytes of Different Subsets in Complexes with Platelets in Patients with Myocardial Infarction

Acute myocardial infarction (AMI) is associated with activation of various cells, including platelets that form monocyte-platelet complexes (MPCs). Here, we analysed MPC in vivo and in vitro and investigated the abilities of different monocyte subclasses to form MPC, the characteristics of the cells involved in MPC formation and MPC changes in AMI. We identified MPC by co-staining for platelet antigen CD41a and monocyte antigens CD14 and CD16. Platelet activation was evaluated from expression of phosphatidylserine as revealed by annexin V. Our results confirm published data and provide new information regarding the patterns of MPC in AMI patients. We found that the patterns of platelet aggregation with monocytes were different in AMI patients and controls: (1) in AMI patients, MPC formed by intermediate monocytes carry more platelets whereas in healthy controls more platelets aggregated with classical monocytes; (2) the numbers of MPC in AMI patients, being already higher than in controls, were further increased if these patients suffered various in-hospital complications; (3) on the basis of the CD41a fluorescence of the antibody-stained MPC, some of the aggregates seem to consist of monocytes and platelet-derived extracellular vesicles (EVs); (4) aggregation of monocytes with platelet EV occurred in in vitro experiments; and (5) these experiments demonstrated that monocytes from AMI patients aggregate with both platelets and platelet EVs more efficiently than do monocytes from controls. MPC in AMI patients may play an important role in this pathology.

Platelet chemiluminescence and endothelial dysfunction in patients with acute myocardial infarction

Е.В. Рыжкова, Н.Б. Рязанкина, А.М. Лебедева, Т.М. Албакова, Р.М. Албакова, З.А. Габбасов, В.В. Коган-Ясный, А.В. Шпектор, Е.Ю. Васильева Кафедра кардиологии, ГБОУ ВПО «Московский государственный медико-стоматологический университет им. А.И. Евдокимова» Минздрава России; ул. Делегатская, 20, стр. 1, Москва, 127473, Российская Федерация; ФГБУ «Российский кардиологический научно-производственный комплекс» Минздрава России; ул. 3-я Черепковская, 15А, Москва, 121552, Российская Федерация; Независимый исследователь