Neutrophilic granulocytes – promiscuous accelerators of atherosclerosis

Neutrophil extracellular trap burden correlates with the stenosis of coronary atherosclerosis

Background

Coronary atherosclerosis diseases (CADs) are associated with chronic inflammation. Neutrophil extracellular traps (NETs) are a type of novel proinflammatory cytokines whose levels are dramatically elevated in acute coronary syndrome. We conducted this study to further evaluate the association between circulating NET-associated markers and CAD in Chinese adults.

Methods

A total of 174 patients with CAD and 55 healthy controls were screened using percutaneous coronary intervention or coronary computed tomography angiography. Blood lipid levels, blood glucose levels, and blood cell counts were determined using commercial kits. Serum levels of myeloperoxidase (MPO) and neutrophil elastase (NE) were measured using ELISA. Double-stranded DNA (dsDNA) in serum was quantified using the Quant-iT PicoGreen assay. We also compared the circulating NET levels with various parameters in the study subjects.

Results

The levels of serum NET markers, dsDNA, MPO, and NE, were significantly elevated in patients with CAD, particularly in the severe group, consistent with the increase in neutrophil counts. The levels of NET markers correlated with the risk factors of AS, increasing with the number of risk factors. NET markers were identified as independent risk factors for severe coronary stenosis and also as predictors of severe CAD.

Conclusion

NETs may be related to AS and serve as indicators or predictors of stenosis in patients with severe CAD.

Neutrophils in aging and aging‐related pathologies

Over the past millennia, life expectancy has drastically increased. While a mere 25 years during Bronze and Iron ages, life expectancy in many European countries and in Japan is currently above 80 years. Such an increase in life expectancy is a result of improved diet, life style, and medical care. Yet, increased life span and aging also represent the most important non-modifiable risk factors for several pathologies including cardiovascular disease, neurodegenerative diseases, and cancer. In recent years, neutrophils have been implicated in all of these pathologies. Hence, this review provides an overview of how aging impacts neutrophil production and function and conversely how neutrophils drive aging-associated pathologies. Finally, we provide a perspective on how processes of neutrophil-driven pathologies in the context of aging can be targeted therapeutically.

Prognostic Nutritional Index as a Predictor of Diabetic Nephropathy Progression

Malnutrition and immunologic derangement were not uncommon in patients with chronic kidney disease (CKD). However, the long-term effects of prognostic nutritional index (PNI), an immunonutrition indictor, on renal outcomes in patients with diabetic nephropathy (DN) and type 2 diabetes mellitus (T2DM) are unknown. In this retrospective cohort study, 475 patients with T2DM and biopsy-confirmed DN from West China Hospital between January 2010 and September 2019 were evaluated. PNI was evaluated as serum albumin (g/L) + 5 × lymphocyte count (109/L). The study endpoint was defined as progression to end-stage renal disease (ESRD). The Cox regression analysis was performed to investigate the risk factors of renal failure in DN patients. A total of 321 eligible individuals were finally included in this study. The patients with higher PNI had a higher eGFR and lower proteinuria at baseline. Correlation analysis indicated PNI was positively related eGFR (r = 0.325, p < 0.001), and negatively correlated with proteinuria (r = −0.68, p < 0.001), glomerular lesion (r = −0.412, p < 0.001) and interstitial fibrosis and tubular atrophy (r = −0.282, p < 0.001). During a median follow-up of 30 months (16−50 months), the outcome event occurred in 164(51.09%) of all the patients. After multivariable adjustment, each SD (per-SD) increment of PNI at baseline was associated with a lower incidence of ESRD (hazard ratio, 0.705, 95% CI, 0.523−0.952, p = 0.023), while the hypoalbuminemia and anemia were not. For the prediction of ESRD, the area under curves (AUC) evaluated with time-dependent receiver operating characteristics were 0.79 at 1 year, 0.78 at 2 years, and 0.74 at 3 years, respectively, and the addition of PNI could significantly improve the predictive ability of the model incorporating traditional risk factors. In summary, PNI correlated with eGFR and glomerular injury and was an independent predictor for DN progression in patients with T2DM. Thus, it may facilitate the risk stratification of DN patients and contribute to targeted management.

High neutrophil to lymphocyte ratio with type 2 diabetes mellitus predicts poor prognosis in patients undergoing percutaneous coronary intervention: a large-scale cohort study

BACKGROUND

Inflammation plays a crucial role in the pathogenesis and progression of coronary artery disease (CAD). The neutrophil to lymphocyte ratio (NLR) is a novel inflammatory biomarker and its association with clinical outcomes in CAD patients with different glycemic metabolism after percutaneous coronary intervention (PCI) remains undetermined. Therefore, this study aimed to investigate the effect of NLR on the prognosis of patients undergoing PCI with or without type 2 diabetes mellitus (T2DM).

METHODS

We consecutively enrolled 8,835 patients with CAD hospitalized for PCI at Fuwai hospital. NLR was calculated using the following formula: neutrophil (*10⁹/L)/lymphocyte (*10⁹/L). According to optimal cut-off value, study patients were categorized as higher level of NLR (NLR-H) and lower level of NLR (NLR-L) and were further stratified as NLR-H with T2DM and non-T2DM, and NLR-L with T2DM and non-T2DM. The primary endpoint was major adverse cardiovascular and cerebrovascular events (MACCEs), defined as all-cause mortality, myocardial infarction (MI), stroke and target vessel revascularization.

RESULTS

A total of 674 (7.6%) MACCEs were recorded during a median follow-up of 2.4 years. The optimal cut-off value of NLR was 2.85 determined by the surv_cutpoint function. Compared to those in the NLR-H/T2DM groups, patients in the NLR-L/non-T2DM, NLR-H/non-T2DM and NLR-L/T2DM groups were at significantly lower risk of 2-year MACCEs [adjusted hazard ratio (HR): 0.67, 95% confidence interval (CI): 0.52 to 0.87, P = 0.003; adjusted HR: 0.62, 95%CI: 0.45 to 0.85, P = 0.003; adjusted HR: 0.77, 95%CI: 0.61 to 0.97, P = 0.025; respectively]. Remarkably, patients in the NLR-L/non-T2DM group also had significantly lower risk of a composite of all-cause mortality and MI than those in the NLR-H/T2DM group (adjusted HR: 0.57, 95%CI: 0.35 to 0.93, P = 0.024). Multivariable Cox proportional hazards model also indicated the highest risk of MACCEs in diabetic patients with higher level of NLR than others (P for trend = 0.009). Additionally, subgroup analysis indicated consistent impact of NLR on MACCEs across different subgroups.

CONCLUSIONS

Presence of T2DM with elevated NLR is associated with worse clinical outcomes in CAD patients undergoing PCI. Categorization of patients with elevated NLR and T2DM could provide valuable information for risk stratification of CAD patients.

Lipoxins modulate neutrophil oxidative burst, integrin expression and lymphatic transmigration differentially in human health and atherosclerosis

Dysregulated chronic inflammation plays a crucial role in the pathophysiology of atherosclerosis and may be a result of impaired resolution. Thus, restoring levels of specialized pro‐resolving mediators (SPMs) to promote the resolution of inflammation has been proposed as a therapeutic strategy for patients with atherosclerosis, in addition to standard clinical care. Herein, we evaluated the effects of the SPM lipids, lipoxin A₄ (LXA₄) and lipoxin B₄ (LXB₄), on neutrophils isolated from patients with atherosclerosis compared with healthy controls. Patients displayed altered endogenous SPM production, and we demonstrated that lipoxin treatment in whole blood from atherosclerosis patients attenuates neutrophil oxidative burst, a key contributor to atherosclerotic development. We found the opposite effect in neutrophils from healthy controls, indicating a potential mechanism whereby lipoxins aid the endogenous neutrophil function in health but reduce its excessive activation in disease. We also demonstrated that lipoxins attenuated upregulation of the high‐affinity conformation of the CD11b/CD18 integrin, which plays a central role in clot activation and atherosclerosis. Finally, LXB₄ enhanced lymphatic transmigration of human neutrophils isolated from patients with atherosclerosis. This finding is noteworthy, as impaired lymphatic function is now recognized as an important contributor to atherosclerosis. Although both lipoxins modulated neutrophil function, LXB₄ displayed more potent effects than LXA₄ in humans. This study highlights the therapeutic potential of lipoxins in atherosclerotic disease and demonstrates that the effect of these SPMs may be specifically tailored to the need of the individual.

Importance of hematological parameters for micro- and macrovascular outcomes in patients with type 2 diabetes: the Rio de Janeiro type 2 diabetes cohort study

Background

The prognostic importance of several hematological parameters has been scarcely investigated in type 2 diabetes. So, we aimed to evaluate their prognostic importance for development of complications in a cohort of type 2 diabetes.

Methods

In a prospective study, 689 individuals with type 2 diabetes had blood red cell, platelet and leukocyte parameters obtained at baseline. Multivariate Cox analyses examined the associations between several hematological parameters (including neutrophyl-to-lymphocyte, lymphocyte-to-monocyte, platelet-to-lymphocyte, and monocyte-to-HDL ratios) and the occurrence of microvascular (retina, renal and peripheral neuropathy) and cardiovascular complications (total cardiovascular events [CVEs], and major adverse CVEs [MACEs]), and all-cause and cardiovascular mortality. Improvements in risk discrimination were assessed by C-statistics and Integrated Discrimination Improvement (IDI) index.

Results

During a median follow-up of 10.5 years, 212 patients had a CVE (174 MACEs), 264 patients died (131 cardiovascular deaths); 206 had a renal, 161 a retinopathy and 179 patients had a neuropathy outcome. In multivariate-adjusted analyses, the lymphocytes count and lymphocyte-to-monocyte ratio were protective (hazard ratios [HRs]: 0.77 and 0.72, respectively), whereas the neutrophyl-to-lymphocyte and platelet-to-lymphocyte ratios were associated with increased risks (HRs: 1.19 and 1.17) for all-cause mortality. For cardiovascular mortality, the monocytes count, the neutrophyl-to-lymphocyte and monocyte-to-HDL ratios were associated with increased risks and the lymphocyte-to-monocyte ratio was protective. Higher lymphocyte-to-monocyte ratio was protective for renal failure outcome. However, none of them improved risk discrimination.

Conclusions

Low lymphocytes count and leukocyte ratios that mainly included lymphocytes were predictors of macrovascular complications and mortality in individuals with type 2 diabetes. However, they did not improve risk prediction over traditional risk factors.

Higher neutrophil-to-lymphocyte ratio (NLR) increases the risk of suboptimal platelet inhibition and major cardiovascular ischemic events among ACS patients receiving dual antiplatelet therapy with ticagrelor

BACKGROUND

Neutrophil to lymphocyte ratio (NLR) has emerged as a useful and easy-to-assess prognostic tool and biomarker of cardiovascular risk. However, few studies have evaluated its role on platelet inhibition among patients on dual antiplatelet therapy (DAPT), and especially in the settings of acute coronary syndromes (ACS). We aimed at assessing the impact of NLR on platelet reactivity and the risk of major ischemic events at long-term follow-up among ACS patients on DAPT with ticagrelor.

METHODS

Patients on dual antiplatelet therapy with ASA + ticagrelor (90 mg/twice a day) after percutaneous coronary revascularization for ACS were scheduled for platelet function assessment 30-90 days post-discharge. Aggregation tests were performed by Multiple Electrode Aggregometry (MEA). Suboptimal platelet inhibition (HRPR-high residual platelet reactivity was defined if above the lower limit of normality (417 AU*min). The primary study endpoint was defined as the occurrence of major cardiovascular events (a composite of cardiovascular death, recurrent acute coronary syndrome, target vessel revascularization) at longest available follow-up.

RESULTS

We included 397 patients, that were divided according to NLR tertiles. Patients with higher NLR were older (p < .001), less frequently smokers (p = .03), with higher rates of renal failure (p = .001), previous bypass surgery (p = .05) and use of statins (p = .03) and diuretics (p = .01). Higher white blood cells count and C-reactive protein (p < .001) and lower haemoglobin (p = .001) were associated with NLR. Mean platelet reactivity and the prevalence of high platelet reactivity (HRPR) on ticagrelor were significantly associated to higher NLR tertiles values (7% vs 12% vs 14.3%, p = .04), with a significant relationship between NLR and platelet reactivity being confirmed for all the different activating stimuli. At a mean follow-up of 939 ± 581.4 days, 21.2% of the patients experienced the primary composite endpoint, with a trend for a higher risk of events across NLR tertiles (15.4% vs 24.2% vs 24.4%, p = .09), that became statistically significant after correction for baseline confounders (adjusted HR[95%CI] = 1.13[1.008-1.26], p = .036). Moreover, NLR was significantly associated to overall mortality and recurrent ACS (adjusted p = .008, p = .06 and p = .02 respectively).

CONCLUSIONS

In the present study we found that among ACS patients treated with ASA and ticagrelor after PCI, suboptimal platelet inhibition despite DAPT was significantly increased for higher values of Neutrophil-to-Lymphocyte Ratio. Moreover, mortality and the risk of recurrent major ischemic events at long-term were associated to NLR.

Neutrophil Extracellular Traps in Periodontitis

Neutrophils are key cells of the immune system and have a decisive role in fighting foreign pathogens in infectious diseases. Neutrophil extracellular traps (NETs) consist of a mesh of DNA enclosing antimicrobial peptides and histones that are released into extracellular space following neutrophil response to a wide range of stimuli, such as pathogens, host-derived mediators and drugs. Neutrophils can remain functional after NET formation and are important for periodontal homeostasis. Periodontitis is an inflammatory multifactorial disease caused by a dysbiosis state between the gingival microbiome and the immune response of the host. The pathogenesis of periodontitis includes an immune-inflammatory component in which impaired NET formation and/or elimination can be involved, contributing to an exacerbated inflammatory reaction and to the destruction of gingival tissue. In this review, we summarize the current knowledge about the role of NETs in the pathogenesis of periodontitis.

Broken sleep predicts hardened blood vessels

Why does poor-quality sleep lead to atherosclerosis? In a diverse sample of over 1,600 individuals, we describe a pathway wherein sleep fragmentation raises inflammatory-related white blood cell counts (neutrophils and monocytes), thereby increasing atherosclerosis severity, even when other common risk factors have been accounted for. Improving sleep quality may thus represent one preventive strategy for lowering inflammatory status and thus atherosclerosis risk, reinforcing public health policies focused on sleep health.

Why does poor quality sleep correlate with cardiovascular disease? A large population-based study suggests that fragmented sleep contributes to atherosclerosis in humans by increasing inflammatory-related activity of white blood cells.

Haematological profile of chronic kidney disease in a mixed-ancestry South African population: a cross-sectional study

OBJECTIVES

The objectives were to characterise the haematological profile of screen-detected chronic kidney disease (CKD) participants and to correlate the complete blood count measures with the commonly advocated kidney function estimators.

METHODS

The current cross-sectional study used data, collected between February 2015 and November 2016, of 1564 adults of mixed-ancestry, who participated in the Cape Town Vascular and Metabolic Health study. Kidney function was estimated using the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations. CKD was defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m², and anaemia as haemoglobin level <13.5 g/dL (men) and <12 g/dL (women).

RESULTS

Based on the MDRD and CKD-EPI equations, the crude prevalence of CKD was 6% and 3%. Irrespective of the equation used, median red blood cell (RBC) indices were consistently lower in those with CKD compared with those without CKD (all p<0.0001). Despite not showing any significant difference in total white blood cell (WBC) count between the two groups, the number of lymphocytes were lower (p=0.0001 and p<0.0001 for MDRD and CKD-EPI, respectively) and neutrophil count (both p<0.0297) and the ratio of lymphocytes to neutrophil (both p<0.0001) higher in the CKD group compared with those without CKD; with the remaining WBC indices similar in the two groups. The platelet count was similar in both groups. Of the screen-detected CKD participants, 45.5% (MDRD) and 57.8% (CKD-EPI) were anaemic, with the prevalence increasing with increasing severity of CKD, from 37.2% (stage 3) to 82.4% (stages 4-5). Furthermore, CKD-EPI-estimated kidney function, but not MDRD, was positively associated with RBC indices.

CONCLUSION

Though it remains unclear whether common kidney function estimators provide accurate estimates of CKD in Africans, the correlation of their estimates with deteriorating RBC profile, suggests that advocated estimators, to some extent approximate kidney function in African populations.

Innate and adaptive immunity in atherosclerosis

Atherosclerosis is a chronic inflammatory disorder of the large and medium-size arteries characterized by the subendothelial accumulation of cholesterol, immune cells, and extracellular matrix. At the early onset of atherogenesis, endothelial dysfunction takes place. Atherogenesis is further triggered by the accumulation of cholesterol-carrying low-density lipoproteins, which acquire properties of damage-associated molecular patterns and thereby trigger an inflammatory response. Following activation of the innate immune response, mainly governed by monocytes and macrophages, the adaptive immune response is started which further promotes atherosclerotic plaque formation. In this review, an overview is given describing the role of damage-associated molecular patterns, NLRP3 inflammasome activation, and innate and adaptive immune cells in the atherogenesis process.

MiR-146a Regulates Neutrophil Extracellular Trap Formation That Predicts Adverse Cardiovascular Events in Patients With Atrial Fibrillation

OBJECTIVE

Atrial fibrillation (AF) patients experience adverse cardiovascular events (ACEs) despite anticoagulant therapy. We reported that rs2431697 of miR-146a, a negative regulator of inflammation, predicts ACEs in patients with AF. The relationship between neutrophil extracellular traps and thrombogenesis is known. Thus, our aim was to evaluate the role of neutrophil extracellular trap compounds as prognostic markers of ACEs in AF and to study whether miR-146a affects NETosis.

APPROACH AND RESULTS

We included 336 steadily anticoagulated AF patients with a median follow-up of 7.9 years (interquartile range, 7.3-8.1) and 127 healthy subjects. The reviewed ACEs included stroke (ischemic/embolic), acute coronary syndrome, acute heart failure, and global or vascular death. We quantified cell-free DNA and NE (neutrophil elastase) at diagnosis. Rs2431697 was genotyped. Neutrophils from human and mice were seeded to analyze shed cell-free DNA and H3cit (citrullinated histone 3) after activation. In human plasmas, higher NE levels (>55.29 ng/mL), but not cell-free DNA, were independently associated with higher risk of all-cause mortality (hazard ratio, 2.24; 95% CI, 1.36-3.68), cardiovascular mortality (hazard ratio, 4.77; 95% CI, 1.11-20.47), and composite cardiovascular events (hazard ratio, 1.84; 95% CI, 1.01-3.76). In patients, NE levels were associated with rs2431697 (TT: 51.82±2.73 versus CC: 40.01±3.05 ng/mL; P=0.040). In vitro, both human (TT for rs2431697) and miR-146a^-/- mice neutrophils yielded higher levels of cell-free DNA and H3cit than CC or wild-type cells, respectively.

CONCLUSIONS

NE activity can provide new ACE prognostic information in AF patients. These findings provide evidence of a potential role of miR-146a in neutrophil extracellular trap generation and cardiovascular risk in AF.

Inflammation in Vein Graft Disease

Bypass surgery is one of the most frequently used strategies to revascularize tissues downstream occlusive atherosclerotic lesions. For venous bypass surgery the great saphenous vein is the most commonly used vessel. Unfortunately, graft efficacy is low due to the development of vascular inflammation, intimal hyperplasia and accelerated atherosclerosis. Moreover, failure of grafts leads to significant adverse outcomes and even mortality. The last couple of decades not much has changed in the treatment of vein graft disease (VGD). However, insight is the cellular and molecular mechanisms of VGD has increased. In this review, we discuss the latest insights on VGD and the role of inflammation in this. We discuss vein graft pathophysiology including hemodynamic changes, the role of vessel wall constitutions and vascular remodeling. We show that profound systemic and local inflammatory responses, including inflammation of the perivascular fat, involve both the innate and adaptive immune system.

Presence of luminal neutrophil extracellular traps in atherosclerosis

Note: The editorial process for this article was fully handled by Prof. G. Y. H. Lip, Editor-in-Chief.

Exploratory analysis of the neutrophil to lymphocyte ratio in patients with pulmonary arterial hypertension

Background

Chronic inflammation emerges as a feature of the pathogenesis of pulmonary arterial hypertension (PAH) in experimental models. Alterations of circulating cell subsets have been observed in patients with PAH. We aimed to assess associations of the white blood cell count with disease severity and outcome in patients with PAH.

Methods

The total and differential white blood cell count was related to functional parameters, pulmonary hemodynamics and transplantation-free survival in 77 patients with PAH in an observational single center study.

Results

An increased neutrophil/lymphocyte ratio was associated with poor World Health Organization functional class and shorter 6-minute walking distance, as well as with elevated right atrial pressure and high level of N-terminal prohormone of brain natriuretic peptide. During a median follow-up period of 31 months (range 16-56) 23 patients died and 2 patients were referred to lung transplantation. Using uni- and subsequent bivariate Cox proportional hazards analyses an increased neutrophil/lymphocyte ratio was associated with unfavorable transplantation-free survival independent of hemodynamic parameters and C-reactive protein. The prognostic implication sustained in subsets of patients with incident PAH and in the absence of cardiovascular risk factors.

Conclusions

The results of this analysis indicate that a neutrophilic inflammation may be associated with clinical deterioration and poor outcome in patients with PAH. Assessing the composition of the differential white blood cell count may render prognostic information and could represent a step towards incorporating an inflammatory marker into the clinical management of patients with PAH.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-017-0407-5) contains supplementary material, which is available to authorized users.

The Relationship between Neutrophil-to-Lymphocyte Ratio and Aortic Arch Calcification in Ischemic Stroke Patients

BACKGROUND

Inflammation plays a central role in atherogenesis and artery calcification. Although neutrophil-to-lymphocyte ratio (NLR) has been introduced as an inflammatory marker for atherosclerosis, the relationship between NLR and aortic arch calcification (AAC) has not been studied. This study aimed to determine the association between NLR and AAC.

METHODS

A total of 749 participants were enrolled. Demographic and clinical data were collected. Degree of AAC in each enrolled patient was determined with Agatston method based on a neck computed tomography angiography. NLR was divided into 4 groups according to quartile values. Generalized linear model (ordinal probit) was performed to assess the association between NLR quartiles and severity of AAC.

RESULTS

There were 151 (20.2%), 153 (20.4%), and 445 (59.4%) patients classified as without AAC, with mild AAC, and with severe AAC, respectively. Patients with severe AAC had the highest NLR values (2.37[1.79-3.42] versus 2.29[1.55-2.96] versus 2.17[1.64-2.91], P = .025) compared to patients without AAC and with mild AAC. In age- and sex-adjusted models, patients with the highest NLR (quartile 4) were correlated with severer AAC (β = .348 ± .128, P = .006) compared to those with the lowest levels (quartile 1). The correlation between NLR quartile 4 and severer AAC still existed (β = .335 ± .129, P = .009) in multivariable-adjusted model.

CONCLUSIONS

This study suggested that NLR may reflect the severity of AAC. NLR may be considered as a valuable predictor of the degree of artery calcification.

An exploratory look at NETosis in atherosclerosis

Current evidence suggests the likelihood of a link between venous thromboembolism (VTE) and atherosclerosis, although they have been traditionally considered as different pathological entities. The contribution of neutrophils to human atherogenesis has been underestimated, if compared to their contribution established in VTE. This is due to the major importance attributed to macrophages in plaque destabilization. Nevertheless, the role of neutrophils in atherogenesis deserves increasing attention. In particular, neutrophil extracellular traps (NETs) are net-like chromatin fibres that are released from dying neutrophils. The death of neutrophils with NETs formation is called NETosis. During activation, neutrophils produce reactive oxygen species (ROS), through the activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. The main function of NETs is trapping and killing pathogens. Nevertheless, NETs formation has been observed in various chronic inflammatory diseases, autoimmune diseases, vasculitis, lung diseases, cancer and VTE. Recent studies suggest that NETs formation might contribute also to atherosclerosis progression. New data report the presence of NETs in the luminal portion of human atherosclerotic vessels and coronary specimens obtained from patients after acute myocardial infarction. Programmed death mechanisms in atherosclerosis such as apoptosis, efferocytosis and also NETosis, share common features and triggers. If defective, they can lead the cells to a switch from programmed death to necrosis, resulting in the release of pro-atherogenic factors, accumulation of cell debris and progression of the disease. This review provides evidence on the emerging role of neutrophils focusing on NETosis and oxidative stress burden in orchestrating common mechanisms in atherosclerosis and thrombosis.

Circulatory Immune Cells in Cushing Syndrome: Bystanders or Active Contributors to Atherometabolic Injury? A Study of Adhesion and Activation of Cell Surface Markers

Glucocorticoids (GC) induce cardiometabolic risk while atherosclerosis is a chronic inflammation involving immunity. GC are immune suppressors, and the adrenocorticotrophic hormone (ACTH) has immune modulator activities. Both may act in atherothrombotic inflammation involving immune cells (IMNC). Aim. To investigate adhesion and activation surface cell markers (CDs) of peripheral IMNC in endogenous Cushing syndrome (CS) and the immune modulator role of ACTH. Material and Methods. 16 ACTH-dependent CS (ACTH-D), 10 ACTH-independent (ACTH-ID) CS, and 16 healthy controls (C) were included. Leukocytes (Leuc), monocytes (MN), lymphocytes (Lym), and neutrophils (N) were analyzed by flow cytometry for atherosclerosis previously associated with CDs. Results. Leuc, N, and MN correlated with CS (p < 0.05), WC (p < 0.001), WHR (p = 0.003), BMI (p < 0.001), and hs-CRP (p < 0.001). CD14⁺⁺CD16⁺ (p = 0.047); CD14⁺CD16⁺⁺ (p = 0.053) MN; CD15⁺ (p = 0.027); CD15⁺CD16⁺ (p = 0.008) N; and NK-Lym (p = 0.019) were higher in CS. CD14⁺CD16⁺⁺ MN were higher in ACTH-ID (8.9 ± 3.5%) versus ACTH-D CS (4.2 ± 1.9%) versus C (4.9 ± 2.3%). NK-Lym correlated with c-LDL (r = 0.433, p = 0.039) and CD15⁺ N with hs-CRP (r = 0.446, p = 0.037). In multivariate analysis, Leuc, N, and MN depended on BMI (p = 0.021), WC (p = 0.002), and WHR (p = 0.014), while CD15⁺ and CD15⁺CD16⁺ N on hypercortisolism and CS (p = 0.035). Conclusion. In CS, IMNC present changes in activation and adhesion CDs implicated in atherothrombotic inflammation. ACTH-IDCS presents a particular IMNC phenotype, possibly due to the absence of the immune modulator effect of ACTH.

Vein graft failure: from pathophysiology to clinical outcomes

Occlusive arterial disease is a leading cause of morbidity and mortality worldwide. Aside from balloon angioplasty, bypass graft surgery is the most commonly performed revascularization technique for occlusive arterial disease. Coronary artery bypass graft surgery is performed in patients with left main coronary artery disease and three-vessel coronary disease, whereas peripheral artery bypass graft surgery is used to treat patients with late-stage peripheral artery occlusive disease. The great saphenous veins are commonly used conduits for surgical revascularization; however, they are associated with a high failure rate. Therefore, preservation of vein graft patency is essential for long-term surgical success. With the exception of 'no-touch' techniques and lipid-lowering and antiplatelet (aspirin) therapy, no intervention has hitherto unequivocally proven to be clinically effective in preventing vein graft failure. In this Review, we describe both preclinical and clinical studies evaluating the pathophysiology underlying vein graft failure, and the latest therapeutic options to improve patency for both coronary and peripheral grafts.

Impact of Neutrophil to Lymphocyte Ratio (NLR) Index and Its Periprocedural Change (NLRΔ) for Percutaneous Coronary Intervention in Patients With Chronic Total Occlusion

We assessed the association between neutrophil to lymphocyte ratio (NLR) and chronic coronary total occlusion (CTO), as well as clinical prognosis of percutaneous coronary intervention (PCI). Patients referred for elective coronary angiography for stable angina pectoris were enrolled, including a CTO (n = 160) and a non-CTO group (n = 160). Neutrophil to lymphocyte ratio on admission and post-PCI was measured, and NLR_Δ was defined as the change between the 2 values. Subgroup analysis was performed based on the value of NLR_Δ (≥0.5 vs <0.5). Clinical characteristics, angiographic data, and follow-up data were recorded. Compared with the non-CTO group, the total white blood cell count, neutrophil counts, and NLR were significantly higher in the CTO group. In the NLR_Δ ≥ 0.5 subgroup, the incidence of severe dissection, slow coronary flow, in-stent restenosis (ISR), and major adverse cardiac events (MACEs) was obviously higher. In multivariate analysis, NLR_Δ was independently and positively associated with higher risks of ISR and MACE. The NLR could be a potential predictor of CTO, and NLR_Δ is independently associated with the adverse clinical outcomes in patients who underwent PCI.

Cathelicidin regulates myeloid cell accumulation in adipose tissue and promotes insulin resistance during obesity

Note: The review process for this manuscript was fully handled by Gregory Y. H. Lip, Editor in Chief.

Shear stress-induced atherosclerotic plaque composition in ApoE(-/-) mice is modulated by connexin37

OBJECTIVE

Shear stress patterns influence atherogenesis and plaque stability; low laminar shear stress (LLSS) promotes unstable plaques whereas oscillatory shear stress (OSS) induces more stable plaques. Endothelial connexin37 (Cx37) expression is also regulated by shear stress, which may contribute to localization of atherosclerotic disease. Moreover, Cx37 reduces initiation of atherosclerosis by inhibiting monocyte adhesion. The present work investigates the effect of Cx37 on the phenotype of plaques induced by LLSS or OSS.

METHODS

Shear stress-modifying casts were placed around the common carotid artery of ApoE(-/-) or ApoE(-/-)Cx37(-/-) mice, and animals were placed on a high-cholesterol diet for 6 or 9 weeks. Atherosclerotic plaque size and composition were assessed by immunohistochemistry.

RESULTS

Plaque size in response to OSS was increased in ApoE(-/-)Cx37(-/-) mice compared to ApoE(-/-) animals. Most plaques contained high lipid and macrophage content and a low amount of collagen. In ApoE(-/-) mice, macrophages were more prominent in LLSS than OSS plaques. This difference was reversed in ApoE(-/-)Cx37(-/-) animals, with a predominance of macrophages in OSS plaques. The increase in macrophage content in ApoE(-/-)Cx37(-/-) OSS plaques was mainly due to increased accumulation of M1 and Mox macrophage subtypes. Cx37 expression in macrophages did not affect their proliferation or their polarization in vitro.

CONCLUSION

Cx37 deletion increased the size of atherosclerotic lesions in OSS regions and abrogated the development of a stable plaque phenotype under OSS in ApoE(-/-) mice. Hence, local hemodynamic factors may modify the risk for adverse atherosclerotic disease outcomes associated to a polymorphism in the human Cx37 gene.

Expression characteristics of neutrophil and mononuclear-phagocyte related genes mRNA in the stable angina pectoris and acute myocardial infarction stages of coronary artery disease

Objective

To investigate expression differences of neutrophil and mononuclear phagocyte related gene mRNAs among acute myocardial infarction (AMI), stable angina (SA) and control groups, and then discuss their expression characteristics in the stable angina pectoris (SAP) and AMI stages of coronary artery disease (CAD).

Methods

Whole Human Genome Oligo Microarrays were applied to assess the differential expression characteristics of neutrophil and mononuclear phagocyte related mRNAs in patients with AMI (n = 20), SA (n = 20) and controls (n = 20).

Results

(1) Almost all colony-stimulating factors (CSF) and their receptors related mRNAs was up-regulated in AMI and SA groups compared with the control group, and the expression of granulocyte-macrophage colony stimulating factor receptor (GM-CSFR) and granulocyte colony stimulating factor receptor (G-CSFR) mRNAs in the AMI group was significantly up-regulated compared with the other two groups (P < 0.01). (2) The expression of mRNAs related to monocyte chemoattractant protein-1 (MCP-1), CCR2 (MCP-1 receptor) and CXCR2 (IL-8 receptor) was significantly up-regulated (P < 0.01) in AMI group compared with SA and control groups. IL-8 mRNA expression in the AMI group was clearly higher than the controls (P < 0.05). (3) All mRNAs expression related to opsonic receptors (IgG FcR and C3bR/C4bR) was significantly up-regulated in AMI group compared with SA and control group (P < 0.01), and the SA group showed an upward trend compared with controls. (4) Most pattern recognition receptor (PRR)-related mRNAs expression was up-regulated in AMI group compared with SA and control groups. Most toll-like receptor (TLR) mRNAs expression was significantly up-regulated (P < 0.01) than the SA and control groups; macrophage scavenger receptor (MSR) mRNA was significantly up-regulated in AMI group compared with the control group (P < 0.01), and the SA group showed an upward trend compared with the controls.

Conclusions

The expression of most neutrophil and mononuclear-macrophage function related genes mRNAs was significantly up-regulated by stages during the progression of CAD, suggesting that the adhesive, chemotactic and phagocytic functions of neutrophil and mononuclear-macrophage were strengthened in the occurrence and development of coronary atherosclerosis and AMI. This also showed a stepped upward trend as the disease progressed.

Neutrophil to Lymphocyte Ratio and the Extent of Coronary Artery Disease: Results From a Large Cohort Study

The neutrophil to lymphocyte ratio (NLR), an inflammatory biomarker, may be of predictive and prognostic value for cardiovascular (CV) events. We evaluated the relationship of NLR with the prevalence and extent of coronary artery disease (CAD) in consecutive patients undergoing elective or urgent coronary angiography. Our population (n = 3738 patients) was divided into NLR quartiles. Higher NLR was associated with aging and established CV risk factors, previous percutaneous coronary revascularization, acute presentation, and more complex pharmacological therapy. The NLR was related to platelet count, white blood cell count, creatinine, glycemia, uric acid, and C-reactive protein (all P = .001) levels but inversely related to hemoglobin (P < .001), total cholesterol (P = .005), and triglycerides (P < .001) levels. The NLR was associated with multivessel disease (P < .001), anterior descending, right coronary arteries (P < .001) or circumflex branch lesions (P = .01), percentage of stenosis (P < .001), coronary calcification (P < .001), and intracoronary thrombus (P < .001) but inversely with in-stent restenosis (P < .001) and thrombolysis in myocardial infarction flow (P = .04). The NLR was directly related to the prevalence of CAD (P = .001) and severe CAD (P < .001). In patients undergoing coronary angiography, the NLR is independently associated with the prevalence and severity of CAD.

Impact of diabetes on neutrophil-to-lymphocyte ratio and its relationship to coronary artery disease

BACKGROUND

Coronary artery disease (CAD) is the leading cause of mortality among diabetic patients, and the neutrophil-to-lymphocyte ratio (NLR) has recently emerged from among inflammatory parameters as a potential indicator of vascular complications and poorer outcome in patients with diabetes. This study aimed to evaluate: 1) the impact of diabetes on NLR; and 2) the role of NLR on the extent of CAD among diabetic patients undergoing coronary angiography.

METHODS

Consecutive patients undergoing coronary angiography were included. Diabetic status and main chemistry parameters were assessed at the time of admission. Significant CAD was defined as at least one vessel with stenosis>50%, while severe CAD was left main and/or three-vessel disease, as evaluated by quantitative coronary angiography (QCA).

RESULTS

Diabetes was observed in 1377 of 3756 patients (36.7%); they were older, and displayed higher-risk cardiovascular profile and more complex CAD. Diabetic status was also associated with a significant increase in NLR (P=0.004). Among diabetics, higher NLR tertile values were related to ageing (P<0.001), dyslipidaemia (P<0.001), renal failure (P<0.001), body mass index (P<0.001), previous percutaneous coronary revascularization (P=0.004) and cerebrovascular events (P=0.003), acute presentation (P<0.001), treatment at admission with beta-blockers/statins/ASA (all P<0.001), diuretics (P=0.01) or clopidogrel (P=0.04), platelet count (P=0.03), white blood cell count, creatinine, glycaemia and C-reactive protein (P<0.001), and inversely related to haemoglobin, triglyceride levels (P<0.001) and smoking (P=0.03). NLR was associated with multivessel disease (P<0.001), degree of stenosis (P=0.01), type C lesions (P=0.02), coronary calcifications and intracoronary thrombus (P<0.001), but inversely with in-stent restenosis (P=0.003) and TIMI flow grade (P=0.02). Also, NLR was directly related to CAD prevalence (P<0.001; adjusted OR [95% CI]: 1.62 [1.27-2.07], P<0.001) and CAD severity (P<0.001; adjusted OR [95% CI]: 1.19 [1.00-1.43], P=0.05).

CONCLUSION

NLR is increased among diabetic patients and, in such patients, is independently associated with the prevalence and severity of CAD. Further studies are now needed to confirm present results and to evaluate the underlying pathophysiological mechanisms behind our findings.

Neutrophils in atherosclerosis: from mice to man

Infiltration of leukocyte subsets is a driving force of atherosclerotic lesion growth, and during the past decade, neutrophils have received growing attention in chronic inflammatory processes, such as atherosclerosis. Equipped with various ready to be released mediators, evolved to fight invading pathogens, neutrophils may also hold key functions in affecting sterile inflammation, such as in atherosclerosis. Many of their secretion products might instruct or activate other immune cells (particularly monocytes) to, for example, enter atherosclerotic lesions or release proinflammatory mediators. Despite the emerging evidence for the mechanistic contribution of neutrophils to early atherosclerosis in mice, their role in human atherogenesis, atheroprogression, and atherosclerotic plaque destabilization is still poorly understood. This brief review will summarize latest findings on the role of neutrophils in atherosclerosis and will pay special attention to studies describing a translation approach by combining measurements in mouse and human.

The CXCL12/CXCR4 chemokine ligand/receptor axis in cardiovascular disease

The chemokine receptor CXCR4 and its ligand CXCL12 play an important homeostatic function by mediating the homing of progenitor cells in the bone marrow and regulating their mobilization into peripheral tissues upon injury or stress. Although the CXCL12/CXCR4 interaction has long been regarded as a monogamous relation, the identification of the pro-inflammatory chemokine macrophage migration inhibitory factor (MIF) as an important second ligand for CXCR4, and of CXCR7 as an alternative receptor for CXCL12, has undermined this interpretation and has considerably complicated the understanding of CXCL12/CXCR4 signaling and associated biological functions. This review aims to provide insight into the current concept of the CXCL12/CXCR4 axis in myocardial infarction (MI) and its underlying pathologies such as atherosclerosis and injury-induced vascular restenosis. It will discuss main findings from in vitro studies, animal experiments and large-scale genome-wide association studies. The importance of the CXCL12/CXCR4 axis in progenitor cell homing and mobilization will be addressed, as will be the function of CXCR4 in different cell types involved in atherosclerosis. Finally, a potential translation of current knowledge on CXCR4 into future therapeutical application will be discussed.

Neutrophil lymphocyte ratio significantly improves the Framingham risk score in prediction of coronary heart disease mortality: insights from the National Health and Nutrition Examination Survey-III

BACKGROUND

Neutrophil lymphocyte ratio (NLR) has been shown to predict cardiovascular events in several studies. We sought to study if NLR predicts coronary heart disease (CHD) in a healthy US cohort and if it reclassifies the traditional Framingham risk score (FRS) model.

METHODS

We performed post hoc analysis of National Health and Nutrition Examination Survey-III (1998-94) including subjects aged 30-79 years free from CHD or CHD equivalent at baseline. Primary endpoint was death from ischemic heart disease. NLR was divided into four categories: <1.5, ≥1.5 to <3.0, 3.0-4.5 and >4.5. Statistical analyses involved multivariate Cox proportional hazards models as well as discrimination, calibration and reclassification.

RESULTS

We included 7363 subjects with a mean follow up of 14.1 years. There were 231 (3.1%) CHD deaths, more in those with NLR>4.5 (11%) compared to NLR<1.5 (2.4%), p<0.001. Adjusted hazard ratio of NLR>4.5 was 2.68 (95% CI 1.07-6.72, p=0.035). There was no significant improvement in C-index (0.8709 to 0.8713) or area under curve (0.8520 to 0.8531) with addition of NLR to FRS model. Model with NLR was well calibrated with Hosmer-Lemeshow chi-square of 8.57 (p=0.38). Overall net reclassification index (NRI) was 6.6% (p=0.003) with intermediate NRI of 10.1% (p<0.001) and net upward reclassification of 5.6%. Absolute integrated discrimination index (IDI) was 0.003 (p=0.039) with relative IDI of 4.3%.

CONCLUSIONS

NLR can independently predict CHD mortality in an asymptomatic general population cohort. It reclassifies intermediate risk category of FRS, with significant upward reclassification. NLR should be considered as an inflammatory biomarker of CHD.

Update on selective treatments targeting neutrophilic inflammation in atherogenesis and atherothrombosis

Atherosclerosis is the most common pathological process underlying cardiovascular diseases. Current therapies are largely focused on alleviating hyperlipidaemia and preventing thrombotic complications, but do not completely eliminate risk of suffering recurrent acute ischaemic events. Specifically targeting the inflammatory processes may help to reduce this residual risk of major adverse cardiovascular events in atherosclerotic patients. The involvement of neutrophils in the pathophysiology of atherosclerosis is an emerging field, where evidence for their causal contribution during various stages of atherosclerosis is accumulating. Therefore, the identification of neutrophils as a potential therapeutic target may offer new therapeutic perspective to reduce the current atherosclerotic burden. This narrative review highlights the expanding role of neutrophils in atherogenesis and discusses on the potential treatment targeting neutrophil-related inflammation and associated atherosclerotic plaque vulnerability.

Molecular biology of atherosclerosis

At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.

ACTH- and cortisol-associated neutrophil modulation in coronary artery disease patients undergoing stent implantation

Background

Psychosocial stress and activation of neutrophil granulocytes are increasingly recognized as major risk factors of coronary artery disease (CAD), but the possible relationship of these two factors in CAD patients is largely unexplored. Activation of neutrophils was reported to be associated with stenting; however, the issue of neutrophil state in connection with percutaneous coronary intervention (PCI) is incompletely understood from the aspect of stress and its hypothalamic-pituitary-adrenal axis (HPA) background. Thus, we aimed to study cortisol- and ACTH-associated changes in granulocyte activation in patients undergoing PCI.

Methodology/Principal Findings

Blood samples of 21 stable angina pectoris (SAP) and 20 acute coronary syndrome (ACS) patients were collected directly before (pre-PCI), after (post-PCI) and on the following day of PCI (1d-PCI). Granulocyte surface L-selectin, CD15 and (neutrophil-specific) lactoferrin were analysed by flow cytometry. Plasma cortisol, ACTH, and lactoferrin, IL-6 were also assayed. In both groups, pre- and post-PCI ratios of lactoferrin-bearing neutrophils were relatively high, these percentages decreased substantially next day; similarly, 1d-PCI plasma lactoferrin was about half of the post-PCI value (all p≤0.0001). Post-PCI ACTH was reduced markedly next day, especially in ACS group (SAP: p<0.01, ACS: p≤0.0001). In ACS, elevated pre-PCI cortisol decreased considerably a day after stenting (p<0.01); in pre-PCI samples, cortisol correlated with plasma lactoferrin (r∼0.5, p<0.05). In 1d-PCI samples of both groups, ACTH showed negative associations with the ratio of lactoferrin-bearing neutrophils (SAP: r = −0.601, p<0.005; ACS: r = −0.541, p<0.05) and with plasma lactoferrin (SAP: r = −0.435, p<0.05; ACS: r = −0.609, p<0.005).

Conclusions/Significance

Pre- and post-PCI states were associated with increased percentage of activated/degranulated neutrophils indicated by elevated lactoferrin parameters, the 1d-PCI declines of which were associated with plasma ACTH in both groups. The correlation of plasma cortisol with plasma lactoferrin in the extremely stressed ACS before stenting, however, suggests an association of cortisol with neutrophil activation.

Pathophysiological role of neutrophils in acute myocardial infarction

The pathogenesis of acute myocardial infarction is known to be mediated by systemic, intraplaque and myocardial inflammatory processes. Among different immune cell subsets, compelling evidence now indicates a pivotal role for neutrophils in acute coronary syndromes. Neutrophils infiltrate coronary plaques and the infarcted myocardium and mediate tissue damage by releasing matrix-degrading enzymes and reactive oxygen species. In addition, neutrophils are also involved in post-infarction adverse cardiac remodelling and neointima formation after angioplasty. The promising results obtained in preclinical modelswith pharmacological approaches interfering with neutrophil recruitment or function have confirmed the pathophysiological relevance of these immune cells in acute coronary syndromes and prompted further studies of these therapeutic interventions. This narrative review will provide an update on the role of neutrophils in acute myocardial infarction and on the pharmacological means that were devised to prevent neutrophil-mediated tissue damage and to reduce post-ischaemic outcomes.

Genetic and pharmacological modifications of thrombin formation in apolipoprotein e-deficient mice determine atherosclerosis severity and atherothrombosis onset in a neutrophil-dependent manner

BACKGROUND

Variations in the blood coagulation activity, determined genetically or by medication, may alter atherosclerotic plaque progression, by influencing pleiotropic effects of coagulation proteases. Published experimental studies have yielded contradictory findings on the role of hypercoagulability in atherogenesis. We therefore sought to address this matter by extensively investigating the in vivo significance of genetic alterations and pharmacologic inhibition of thrombin formation for the onset and progression of atherosclerosis, and plaque phenotype determination.

METHODOLOGY/PRINCIPAL FINDINGS

We generated transgenic atherosclerosis-prone mice with diminished coagulant or hypercoagulable phenotype and employed two distinct models of atherosclerosis. Gene-targeted 50% reduction in prothrombin (FII(-/WT):ApoE(-/-)) was remarkably effective in limiting disease compared to control ApoE(-/-) mice, associated with significant qualitative benefits, including diminished leukocyte infiltration, altered collagen and vascular smooth muscle cell content. Genetically-imposed hypercoagulability in TM(Pro/Pro):ApoE(-/-) mice resulted in severe atherosclerosis, plaque vulnerability and spontaneous atherothrombosis. Hypercoagulability was associated with a pronounced neutrophilia, neutrophil hyper-reactivity, markedly increased oxidative stress, neutrophil intraplaque infiltration and apoptosis. Administration of either the synthetic specific thrombin inhibitor Dabigatran etexilate, or recombinant activated protein C (APC), counteracted the pro-inflammatory and pro-atherogenic phenotype of pro-thrombotic TM(Pro/Pro):ApoE(-/-) mice.

CONCLUSIONS/SIGNIFICANCE

We provide new evidence highlighting the importance of neutrophils in the coagulation-inflammation interplay during atherogenesis. Our findings reveal that thrombin-mediated proteolysis is an unexpectedly powerful determinant of atherosclerosis in multiple distinct settings. These studies suggest that selective anticoagulants employed to prevent thrombotic events may also be remarkably effective in clinically impeding the onset and progression of cardiovascular disease.

Regulation of atherogenesis by chemokines and chemokine receptors

Atherosclerosis is a chronic inflammatory and metabolic disorder affecting large- and medium-sized arteries, and the leading cause of mortality worldwide. The pathogenesis of atherosclerosis involves accumulation of lipids and leukocytes in the intima of blood vessel walls creating plaque. How leukocytes accumulate in plaque remains poorly understood; however, chemokines acting at specific G protein-coupled receptors appear to be important. Studies using knockout mice suggest that chemokine receptor signaling may either promote or inhibit atherogenesis, depending on the receptor. These proof of concept studies have spurred efforts to develop drugs targeting the chemokine system in atherosclerosis, and several have shown beneficial effects in animal models. This study will review key discoveries in basic and translational research in this area.

Neuroimmunology of the atherosclerotic plaque: a morphological approach

Atherosclerosis is a chronic inflammatory process, lasting for several decades until the onset of its clinical manifestations. The progression of the atherosclerotic lesion to a stable fibrotic plaque, narrowing the vascular lumen, or to a vulnerable plaque leading to main vascular complications, is associated to the involvement of several cell subpopulations of the innate as well as of the adaptive immunity, and to the release of chemokines and pro-inflammatory cytokines. Emerging evidence outlines that the cardiovascular risk is dependent on stress-mediators influencing cell migration and vascular remodeling. The view that atherosclerosis is initiated by monocytes and lymphocytes adhering to dysfunctional endothelial cells is substantiated by experimental and clinical observations. Macrophages, dendritic cells, T and B lymphocytes, granulocytes accumulating into the subendothelial space secrete and are stimulated by soluble factors, including peptides, proteases and cytokines acting synergistically. The final step of the disease, leading to plaque destabilization and rupture, is induced by the release, at the level of the fibrous cap, of metalloproteinases and elastases by the activated leukocytes which accumulate locally. Recruitment of specific cell subpopulations as well as the progression of atherosclerotic lesions towards a stable or an unstable phenotype, are related to the unbalance between pro-atherogenic and anti-atherogenic factors. In this connection stress hormones deserve particular attention, since their role in vascular remodeling, via vascular smooth cell proliferation, as well as in neoangiogenesis, via stimulation of endothelial cell proliferation and migration, has been already established.

Neutrophil-lymphocyte ratio as a predictor of major adverse cardiac events among diabetic population: a 4-year follow-up study

The neutrophil-lymphocyte ratio (NLR) is an inflammatory marker of major adverse cardiac events (MACEs) in both acute coronary syndromes and stable coronary artery disease. The use of NLR as a predictive tool for MACEs among diabetic patients has not been elucidated. An observational study included 338 diabetic patients followed at our clinic between 2007 and 2011. Patients were arranged into equal tertiles according to the 2007 NLR. The MACEs included acute myocardial infarction, coronary revascularization, and mortality. The lowest NLR tertile (NLR < 1.6) had fewer MACEs compared with the highest NLR tertile (NLR > 2.36; MACEs were 6 of 113 patients vs 24 of 112 patients, respectively; P < .0001). In a multivariate model, the adjusted hazard ratio of third NLR tertile compared with first NLR tertile was 2.8 (95% confidence interval 1.12-6.98, P = .027). The NLR is a significant independent predictor of MACEs in diabetic patients. Further studies with larger numbers are needed.

Role of Peroxisome Proliferator-Activated Receptor-γ in Vascular Inflammation

Vascular inflammation plays a crucial role in atherosclerosis, and its regulation is important to prevent cerebrovascular and coronary artery disease. The inflammatory process in atherogenesis involves a variety of immune cells including monocytes/macrophages, lymphocytes, dendritic cells, and neutrophils, which all express peroxisome proliferator-activated receptor-γ (PPAR-γ). PPAR-γ is a nuclear receptor and transcription factor in the steroid superfamily and is known to be a key regulator of adipocyte differentiation. Increasing evidence from mainly experimental studies has demonstrated that PPAR-γ activation by endogenous and synthetic ligands is involved in lipid metabolism and anti-inflammatory activity. In addition, recent clinical studies have shown a beneficial effect of thiazolidinediones, synthetic PPAR-γ ligands, on cardiovascular disease beyond glycemic control. These results suggest that PPAR-γ activation is an important regulator in vascular inflammation and is expected to be a therapeutic target in the treatment of atherosclerotic complications. This paper reviews the recent findings of PPAR-γ involvement in vascular inflammation and the therapeutic potential of regulating the immune system in atherosclerosis.

Connexins in atherosclerosis

Atherosclerosis, a chronic inflammatory disease of the vessel wall, involves multiple cell types of different origins, and complex interactions and signaling pathways between them. Autocrine and paracrine communication pathways provided by cytokines, chemokines, growth factors and lipid mediators are central to atherogenesis. However, it is becoming increasingly recognized that a more direct communication through both hemichannels and gap junction channels formed by connexins also plays an important role in atherosclerosis development. Three main connexins are expressed in cells involved in atherosclerosis: Cx37, Cx40 and Cx43. Cx37 is found in endothelial cells, monocytes/macrophages and platelets, Cx40 is predominantly an endothelial connexin, and Cx43 is found in a large variety of cells such as smooth muscle cells, resident and circulating leukocytes (neutrophils, dendritic cells, lymphocytes, activated macrophages, mast cells) and some endothelial cells. Here, we will systematically review the expression and function of connexins in cells and processes underlying atherosclerosis. This article is part of a Special Issue entitled: The Communicating junctions, roles and dysfunctions.