Post-reperfusion changes of monocyte function in coronary blood after extracorporeal circulation

Association of Circulating Neutrophils with Relative Volume of Lipid-Rich Necrotic Core of Coronary Plaques in Stable Patients: A Substudy of SMARTool European Project

BACKGROUND AND AIMS

Coronary atherosclerosis is a chronic non-resolving inflammatory process wherein the interaction of innate immune cells and platelets plays a major role. Circulating neutrophils, in particular, adhere to the activated endothelium and migrate into the vascular wall, promoting monocyte recruitment and influencing plaque phenotype and stability at all stages of its evolution. We aimed to evaluate, by flow cytometry, if blood neutrophil number and phenotype-including their phenotypic relationships with platelets, monocytes and lymphocytes-have an association with lipid-rich necrotic core volume (LRNCV), a generic index of coronary plaque vulnerability, in a group of stable patients with chronic coronary syndrome (CCS).

METHODS

In 55 patients, (68.53 ± 1.07 years of age, mean ± SEM; 71% male), the total LRNCV in each subject was assessed by a quantitative analysis of all coronary plaques detected by computed tomography coronary angiography (CTCA) and was normalized to the total plaque volume. The expression of CD14, CD16, CD18, CD11b, HLA-DR, CD163, CCR2, CCR5, CX3CR1, CXCR4 and CD41a cell surface markers was quantified by flow cytometry. Adhesion molecules, cytokines and chemokines, as well as MMP9 plasma levels, were measured by ELISA.

RESULTS

On a per-patient basis, LRNCV values were positively associated, by a multiple regression analysis, with the neutrophil count (n°/µL) (p = 0.02), neutrophil/lymphocyte ratio (p = 0.007), neutrophil/platelet ratio (p = 0.01), neutrophil RFI CD11b expression (p = 0.02) and neutrophil-platelet adhesion index (p = 0.01). Significantly positive multiple regression associations of LRNCV values with phenotypic ratios between neutrophil RFI CD11b expression and several lymphocyte and monocyte surface markers were also observed. In the bivariate correlation analysis, a significantly positive association was found between RFI values of neutrophil-CD41a+ complexes and neutrophil RFI CD11b expression (p < 0.0001).

CONCLUSIONS

These preliminary findings suggest that a sustained increase in circulating neutrophils, together with the up-regulation of the integrin/activation membrane neutrophil marker CD11b may contribute, through the progressive intra-plaque accumulation of necrotic/apoptotic cells exceeding the efferocytosis/anti-inflammatory capacity of infiltrating macrophages and lymphocytes, to the relative enlargement of the lipid-rich necrotic core volume of coronary plaques in stable CAD patients, thus increasing their individual risk of acute complication.

Venoarterial extracorporeal membrane oxygenation induces early immune alterations

Background

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) provides heart mechanical support in critically ill patients with cardiogenic shock. Despite important progresses in the management of patients under VA-ECMO, acquired infections remain extremely frequent and increase mortality rate. Since immune dysfunctions have been described in both critically ill patients and after surgery with cardiopulmonary bypass, VA-ECMO initiation may be responsible for immune alterations that may expose patients to nosocomial infections (NI). Therefore, in this prospective study, we aimed to study immune alterations induced within the first days by VA-ECMO initiation.

Methods

We studied immune alterations induced by VA-ECMO initiation using cytometry analysis to characterize immune cell changes and enzyme-linked immunosorbent assay (ELISA) to explore plasma cytokine levels. To analyze specific changes induced by VA-ECMO initiation, nine patients under VA-ECMO (VA-ECMO patients) were compared to nine patients with cardiogenic shock (control patients).

Results

Baseline immune parameters were similar between the two groups. VA-ECMO was associated with a significant increase in circulating immature neutrophils with a significant decrease in C5a receptor expression. Furthermore, we found that VA-ECMO initiation was followed by lymphocyte dysfunction along with myeloid-derived suppressor cells (MDSC) expansion. ELISA analysis revealed that VA-ECMO initiation was followed by an increase in pro-inflammatory cytokines such as IL-6, IL-8 and TNF-α along with IL-10, a highly immunosuppressive cytokine.

Conclusion

VA-ECMO is associated with early immune changes that may be responsible for innate and adaptive immune alterations that could confer an increased risk of infection.

Blood Monocyte Phenotype Fingerprint of Stable Coronary Artery Disease: A Cross-Sectional Substudy of SMARTool Clinical Trial

Background and Aims

Atherosclerosis is an inflammatory disease with long-lasting activation of innate immunity and monocytes are the main blood cellular effectors. We aimed to investigate monocyte phenotype (subset fraction and marker expression) at different stages of coronary atherosclerosis in stable coronary artery disease (CAD) patients.

Methods

73 patients with chronic coronary syndrome were evaluated by CT coronary angiography (CTCA) and classified by maximal diameter stenosis of major vessels into three groups of CAD severity: CAD1 (no CAD/minimal CAD, n° = 30), CAD2 (non-obstructive CAD, n° = 21), and CAD3 (obstructive CAD, n° = 22). Flow cytometry for CD14, CD16, and CCR2 was used to quantify Mon1, Mon2, and Mon3 subsets. Expression of CD14, CD16, CD18, CD11b, HLA-DR, CD163, CCR2, CCR5, CX3CR1, and CXCR4 was also measured. Adhesion molecules and cytokines were quantified by ELISA.

Results

Total cell count and fraction of Mon2 were higher in CAD2 and CAD3 compared to CAD1. By multivariate regression analysis, Mon2 cell fraction and Mon2 expression of CX3CR1, CD18, and CD16 showed a statistically significant and independent increase, parallel to stenosis severity, from CAD1 to CAD2 and CAD3 groups. A similar trend was also present for CX3CR1 and HLA-DR expressions on total monocyte population. A less calcified plaque composition was associated to a higher Mon2 expression of CD16 and higher TNF-α levels. IL-10 levels were lower at greater stenosis severity, while the IFN-γ/IL-10 ratio, a marker of a systemic pro-inflammatory imbalance, was directly correlated to stenosis degree and number of noncalcified plaques.

Conclusions

The results of this study suggest that a specific pattern of inflammation-correlated monocyte marker expression is associated to higher stenosis severity and less calcified lesions in stable CAD. The clinical trial Identifier is NCT04448691.

Differential modulatory effects of Propofol and Sevoflurane anesthesia on blood monocyte HLA-DR and CD163 expression during and after cardiac surgery with cardiopulmonary bypass: a preliminary randomized flow cytometry study

INTRODUCTION

The increase of the anti-inflammatory CD163^highHLA-DR^low blood monocyte subset is one of the mechanisms dampening inflammation during cardiac surgery with cardiopulmonary bypass. We evaluated the effect of two different anesthetic protocols, intravenous Propofol infusion or Sevoflurane-gas administration, on the perioperative frequency of this subset.

METHODS

Blood from patients (Propofol = 11, Sevoflurane = 13) undergoing minimally invasive mitral valve surgery was drawn preoperatively (T1), before declamping (T2), at 6 (T3), 24 (T4), 48 (T5), and 72 hours (T6) after declamping. C-reactive protein, haptoglobin, and lactate dehydrogenase were measured. A hemolytic index, as C-reactive protein/haptoglobin ratio, was introduced. Monocyte expression of HLA-DR, CD163, and the CD163^highHLA-DR^low subset fraction was quantified by flow cytometry. Baseline-referred variations of plasmatic and cellular data at T2 were normalized for clamping times. Subsequent time-point variations were normalized for the final cardiopulmonary bypass times.

RESULTS

Variations of hemolytic index and lactate dehydrogenase were higher with Propofol at T3 (p = 0.004 and p = 0.02, respectively) when compared with Sevoflurane. At T2, the down-modulation of CD163 was higher with Propofol (p = 0.005). Starting from T3, the up-regulatory trend of CD163 was basically higher with Propofol, although not significantly. Propofol induced higher increments of HLA-DR low fractions, at T2 (p = 0.04) and, to a lesser extent, at T4 (p = 0.06). Starting from T3, the CD163^highHLA-DR^low subset variations were higher with Propofol, especially at T4 and T6.

CONCLUSION

Propofol seems to induce a higher postoperative fraction of the CD163^highHLA-DR^low monocyte subset. This could represent either a compensatory mechanism dampening the higher inflammatory condition observed with Propofol at T2 or a consequence of a higher postoperative Propofol-induced hemolysis.

Relationships Between Phenotype and Function of Blood CD4+ T-Cells and Ascending Thoracic Aortic Aneurysm: an Experimental Study

Introduction

Non-familial ascending thoracic aorta dilation and aneurysms (TAAs) are silent diseases in elderly patients. Histopathology revealed that functionally polarized infiltrating CD4⁺ T-cells play a key role in aortic wall weakening.

Objective

To evaluate the possible associations between phenotype and cytokine production of circulating CD4⁺ T-lymphocytes and the presence of TAA in patients with aortic valve disease (AVD).

Methods

We studied blood samples from 10 patients with TAA and 10 patients with AVD. Flow cytometry was used to quantify: a) CD4⁺ T-lymphocytes surface expression of CD25, CD28, and chemokine receptors (CCR5, CXCR3, CX3CR1); b) fractions of in vitro stimulated CD4⁺ T-cells producing cytokines (interferon gamma [IFN-γ], interleukin [IL]-17A, IL-21, IL-10); c) CD4⁺CD25^highFoxP3⁺ regulatory T-cells (Treg) fraction. Enzyme-linked immunosorbent assays (ELISA) were performed for cytokines (IFN-γ, IL-6, IL-10, IL-17A, IL-23, transforming growth factor beta [TGF-β]) and chemokines (RANTES, CX3CL1).

Results

The total CD4⁺CD28^±CD4⁺/CX3CR1⁺ T-cells fraction was higher (P=0.0323) in AVD (20.452±4.673) than in TAA patients (8.633±2.030). The frequency ratio of CD4⁺ T-lymphocytes producing IFN-γ vs. IL-17A+IL-21 cytokine-producing CD4+ T-cells was higher (P=0.0239) in AVD (2.102±0.272) than in TAA (1.365±0.123) patients. The sum of CD4⁺CD28^±CD4⁺/CX3CR1⁺ T-cells correlated positively with values of the previous cytokine ratio (P=0.0002, R=0.732). The ratio of CD4⁺CD28^±CD4⁺/CX3CR1⁺ T-cells vs. Treg was higher (P=0.0008) in AVD (20.859±3.393) than in TAA (6.367±1.277) patients.

Conclusion

Our results show that the presence of TAA in subjects with AVD is associated with imbalance between phenotypic and cytokine-producing subsets of circulating CD4+ T-lymphocytes, prevalently oriented towards a pro-fibrotic and IFN-γ counteracting effect to functional polarization.

Comparison of the clinical application of reactive oxygen species and inflammatory markers in patients with endocarditis

INTRODUCTION

Infective endocarditis (IE) is still connected with high operative mortality. Inflammatory markers are commonly used in monitoring patient clinical condition. Respiratory burst and reactive oxygen species (ROS) are the main way of pathogen elimination. Specificity of this process in the aspect of bacterial infection is the key for correlation assessment between ROS and inflammatory markers in patients with IE. In the study, assessment of ROS as a clinical indicator in IE was conducted.

MATERIAL AND METHODS

During 2007/2008 in the Cardiosurgical Clinic of the Medical University in Lodz there were 20 patients operated on for IE. The examined population consisted of 13 men and 7 women, aged from 23 to 74 years. Inflammatory markers - leukocytosis (WBC), C-reactive protein (CRP), procalcitonin (PCT) and erythrocyte sedimentation rate (ESR) - were assessed preoperatively, on the 3(rd), 7(th), 12(th) and 21(st) day. Simultaneously, with the second venous blood sample chemiluminescence (luminal enhanced whole blood chemiluminescence) was carried out and used to assess ROS production. The results were analyzed statistically.

RESULTS

Positive correlation between ESR, CRP and ROS in the preoperative period was confirmed. An increase in ROS and a statistically significant increase in inflammatory markers on the 3(rd) day were observed. The ROS normalized on the 12(th) day. Marked individual variability was specific for the inflammatory markers. Despite the significant decrease, not all of them achieved a normal level at the last control point.

CONCLUSIONS

Assessment of ROS seems to be a universal parameter with possible application in patients with IE.

Oxidant alterations in CD16 expression are cytoskeletal induced

Oxidative stress during reperfusion of ischemia is associated with a phenotypic change in circulating monocytes from CD14++CD16- to a proinflammatory CD14+CD16+ subpopulation resulting in altered immunity and development of organ failure. However, the mechanism responsible remains unknown. We hypothesize that this phenotypic change, modeled by hydrogen peroxide exposure in vitro, is due to oxidative-induced intracellular calcium flux and distinct cytoskeletal and lipid raft changes. Peripheral blood monocytes obtained from healthy volunteers underwent 100 mM H2O2 exposure for 0 to 24 h. Selected cells were pretreated with 2 microM cytochalasin D, 1 microM lactrunculin A, or 30 microM 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid for 30 min. Cells underwent fluorescence-activated cell sorter for CD14, CD16, and cytokine expression. Cellular and lipid raft CD16 expression was determined by immunoblot and confocal microscopy. H2O2 exposed monocytes underwent a rapid time-dependent increase in the surface expression of CD16 from 12.81% +/- 3.53% to 37.12% +/- 7.61% at 24 h (P = 0.001). Total cellular CD16 was not changed by H2O2, but an increase in lipid raft and decrease in intracellular CD16 expression were seen after H2O2 exposure. This increase in CD16 expression was associated with a 27% increase in intracellular TNF-alpha, an alteration in actin polymerization, and the formation of raft macrodomains. These changes induced by H2O2 were inhibited by inhibition of actin polymerization (cytochalasin D and lactrunculin A) and intracellular calcium flux [1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid]. This study provides the first evidence that phenotypic alterations induced by oxidative stress during reperfusion may occur as a result of changes in cytoskeletal architecture due to calcium flux that result in lipid raft alterations rather than solely from demargination and/or production of bone marrow-derived CD16+ monocytes.

TNF-alpha inhibits toll-like receptor 4 expression on monocytic cells via tristetraprolin during cardiopulmonary bypass

Toll-like receptor 4 (TLR4) plays a major role in regulating the innate immune response, which is related to postoperative complications. Although inflammatory capacity and TNF-alpha synthesis were altered on monocytes after cardiopulmonary bypass (CPB), whether the CPB and the CPB-induced TNF-alpha affect TLR4 expression on monocytes have not yet clarified. We speculate that the changing of TNF-alpha level during CPB may be involved in monocytic TLR4 expression. As previous report, our enzyme-linked immunosorbent assay showed that CPB elevated the plasma level of TNF-alpha, whereas off-pump cardiac surgery does not. Flow cytometry reported decreased levels of monocytic TLR4 in patients undergoing CPB but not undergoing off-pump cardiac surgery. To elucidate whether the CPB-induced TNF-alpha is related to TLR4 down-regulation, we used human monocytic THP-1 cells. Actinomycin D chase experiments demonstrated that TNF-alpha decreased TLR4 expression and TLR4 mRNA stability on THP-1. Confocal microscopy and real-time polymerase chain reaction showed that TNF-alpha induced intracellular tristetraprolin (TTP) expression. Transfection with TTP siRNA reversed the down-regulation of TLR4 in TNF-alpha-stimulated THP-1. Treatment with ERK1/2 inhibitor and SAPK/JNK inhibitor decreased TNF-alpha-induced TTP expression. Immunoprecipitation and Western blot analysis showed that the TNF-alpha-mediated activation of TTP might be inhibited by p38 mitogen-activated protein kinase inhibitor and by PD98059. We also demonstrated in clinical samples with confocal microscopy and flow cytometry that CPB led to an elevation of TTP in monocytes. In conclusion, CPB and TNF-alpha decrease TLR4 expression on monocytes; TTP expression and mitogen-activated protein kinase-signaling pathways play critical roles in CPB- and TNF-alpha-mediated decreases of TLR4 on monocytes. Our results suggest that using TTP to control cytokine message decay rate may be a promising approach for controlling system inflammation and preventing post-CPB complications.

Relationships between optical aggregometry (type born) and flow cytometry in evaluating ADP-induced platelet activation

BACKGROUND

Platelet response to activating agents is used to monitor the efficacy of anti-aggregation therapies. The aim of our study has been to demonstrate the existence of relationships between early events of ADP-induced platelet activation, measured by flow cytometry and platelet-rich plasma aggregation, quantified by optical aggregometry.

METHODS

We evaluated peripheral blood of 12 donors. The following parameters were quantified by cytometry after stimulation with adenosine diphosphate (ADP) (0.5, 1, 2, 5, 10, 20 muM): CD62P (P-selectin) and PAC-1 expression, and cytosolic Ca(2+) mobilization. Aggregation was measured by optical aggregometry. We also studied 13 patients, undergoing coronary stenting, treated with aspirin (before procedure) or with aspirin plus clopidogrel (after procedure). We evaluated CD62P and PAC-1 expression, aggregation, and vasodilator-stimulated phopshoprotein phosphorylation (platelet reactivity index, PRI).

RESULTS

Flow procedures were more sensitive than aggregometry, with a lowest interindividual variability. Linear relationships existed in donors between CD62P expression and Ca(2+) mobilization (P < 0.0001), and between aggregation and Ca(2+) mobilization (P < 0.0001). Linear relationships existed between aggregation and CD62P expression, as percentage (P < 0.0001), or relative fluorescence intensity (RFI) (P < 0.0001). Exponential equations related aggregation and PAC-1 expression, as percentage (P < 0.0001), or RFI (P < 0.0001). Linear relationships between aggregation and CD62P expression (as percentage) existed in the patients before (P = 0.0022) and after procedure (P = 0.0020). Exponential relationships between aggregation and PAC-1 expression (as percentage) existed before (P = 0.0012) and after procedure (P = 0.0024). Linear correlations related aggregation response predicted on CD62P expression, and measured aggregation inhibition after clopidogrel (P = 0.0013) as well as predicted aggregation and PRI inhibition (P = 0.0031).

CONCLUSIONS

Tight relationships between aggregation and cytometric quantification of platelet markers in whole blood, in particular CD62P, allow to predict aggregation response to ADP from flow data in patients treated with aspirin alone or with aspirin plus clopidogrel.

An increased platelet–leukocytes interaction at the culprit site of coronary artery occlusion in acute myocardial infarction: A pathogenic role for “no-reflow” phenomenon?

BACKGROUND

Distal protection devices have been shown to reduce the incidence of "no flow" phenomenon during primary percutaneous coronary intervention (PCI). So far, it has not been well clarified which mechanism is mainly involved in distal coronary protection.

AIM

To investigate the activation state of leukocytes and platelets locally present within the blood from the site of coronary occlusion.

METHODS

Ten patients with acute myocardial infarction (AMI) underwent primary PCI with an embolization protection device and aspiration catheter (PercuSurge GuardWire) were included. The following functional parameters: a) monocyte and neutrophils surface molecules; b) platelet surface activatory antigens; c) leukocytes-platelet conjugates were studied by flow cytometry in blood obtained from the site of coronary occlusion and from peripheral femoral artery.

RESULTS

The leukocyte-platelet adhesion index was significantly higher in the aspirated blood at the site of coronary occlusion than in the peripheral arterial blood for both monocytes (0.226+/-0.04 vs. 0.084+/-0.01; p=0.004) and neutrophils (1.372+/-0.3 vs. 0.524+/-0.1; p=0.02). Moreover, the volume of coaggregates exhibited a significant increase in coronary blood for both populations (p=0.02 for monocytes and for neutrophils). Interestingly, a significant up-regulation of the adhesive molecule CD18 was observed in coronary blood respect to systemic circulation either in monocytes (p=0.01) than in neutrophils (p=0.003). A significant up-regulation of monocyte (HLA-DR) and neutrophil (CD66b) activatory molecules expression was also observed in the aspirated coronary compared to peripheral artery blood (p=0.02 and p=0.03 for HLA-DR and CD66b, respectively).

CONCLUSIONS

These data indicate an increased leukocyte-platelet functional interaction in AMI at the site of plaque rupture relative to the systemic circulation, which may be one of the pathogenetic mechanisms responsible for myocardial "no-reflow" phenomenon.

Granulocyte– and monocyte–platelet adhesion index in coronary and peripheral blood after extracorporeal circulation and reperfusion

BACKGROUND

Neutrophil-granulocyte and mononuclear-cell functional changes occur during cardiopulmonary bypass and cardiovascular surgery. In particular, leukocyte-platelet interaction, leading to generation of heterotypic coaggregates, represents an amplification mechanism of the local inflammatory response and tissue damage.

METHODS

Samples of 20 patients were drawn from venous coronary sinus before cardioplegic arrest and immediately after reperfusion, as well as from peripheral blood at 5 and 24 h postoperatively. The granulocyte and monocyte surface expression of CD162, CD15s, CD18, and CD11b were quantified by flow cytometry at the different times. Parallel variations of circulating leukocyte-platelet conjugates (percentages) and a derived (cell number-normalized) leukocyte-platelet adhesion index were measured using a combination of antibodies against CD45, CD14, and CD41a. The evaluation of platelet functional state was carried out using antibodies against CD62P (P-selectin) and PAC-1.

RESULTS

Monocyte and granulocyte cell number increased markedly in coronary blood at reperfusion and in peripheral blood postoperatively when compared with measurements done before cardioplegia. A very different course characterized the changes of the leukocyte-platelet adhesion index with respect to the variations of circulating leukocyte-platelet coaggregates (percentages). Leukocyte molecules expression showed no significant variations for CD15s on both the leukocyte subsets, while a significant up-modulation for CD162 was observed on monocytes at 24 h after extracorporeal circulation (P = 0.0002), and for CD11b on granulocytes at 5 h postoperatively (P = 0.033). A loss of CD162 expression was observed in coronary blood at reperfusion (P = 0.0038) on granulocytes, associated to a down-modulation of CD18 (P = 0.0033) and CD11b (P = 0.0184) in peripheral blood at 24 h postoperatively. No significant up-regulation of platelet activatory molecules expression was found at coronary reperfusion, as well as postoperatively in the peripheral blood, when compared with the before-cardioplegia derived data.

CONCLUSIONS

The over time variations of a normalized leukocyte-platelet adhesion index seem to reflect the cumulative leukocyte-platelet functional interaction more accurately than the parallel measurements of cellular conjugates. The absence of platelet activation suggests that the leukocyte membrane modifications play a main role in controlling the formation and stability of heterotypic leukocyte-platelet coaggregates after cardiac surgery with extracorporeal circulation.

Is there an association between angiotensin-converting enzyme gene polymorphism and functional activation of monocytes and macrophage in young patients with essential hypertension?

BACKGROUND

This study was undertaken to determine whether the phenotype of monocytes and monocyte-derived macrophages is more proatherogenic in young persons with arterial hypertension and whether this phenotype is affected by smoking or polymorphism of the angiotensin-converting enzyme (ACE) gene.

METHODS

We enrolled 40 young patients (24.1 +/- 4.7 years) with previously untreated arterial hypertension and 40 age-matched healthy controls. There were 20 smokers and 20 non-smokers in each group.

RESULTS

In the hypertensive group, we found enhanced monocyte expression of CD11a (P < 0.001), reduced expression of CD49d (P < 0.001) and CD62L (P < 0.005), greater oxidative stress in resting and phorbol-12-mistrate-13-acetate-stimulated monocytes (P < 0.001), enhanced adhesion of monocytes to endothelial cells (P < 0.001), greater expression of CD36 on monocyte-derived macrophages (P < 0.001), and enhanced production of reactive oxygen species by resting and phorbol-12-mistrate-13-acetate-stimulated macrophages (P < 0.001). Cigarette smoking by hypertensive patients was associated with enhanced (P < 0.002) CD11a expression. There were no associations of ACE gene polymorphism with cellular expression or reactive oxygen species production studied among hypertensive patients. Only CD62L expression in DD homozygote participants was higher (P < 0.039) than in II homozygote participants.

CONCLUSIONS

It is concluded that arterial hypertension affects the function of monocytes/macrophages in young persons. Polymorphism of the ACE gene is without effect on the functional activation of monocytes and macrophages.