Upregulation of the CD40/CD40 Ligand Dyad and Platelet-Monocyte Aggregation in Cigarette Smokers

Blocking CD40 Alleviates Th1 and Th17 Cell Responses in Elastin Peptide-Induced Murine Emphysema

Purpose

To investigate the role of the CD40-CD40 ligand (CD40L) pathway in the regulation of Th1, Th17, and regulatory T (Treg)-cell responses in an elastin peptide (EP)-induced autoimmune emphysema mouse model.

Methods

BALB/c mice were transnasally treated with EP on day 0, injected intravenously with anti-CD40 antibody via the tail vein on day 33, and sacrificed on day 40. The severity of emphysema was evaluated by determining the mean linear intercept (MLI) and destructive index (DI) from lung sections. The proportions of myeloid dendritic cells (mDCs) and Th1, Th17, and Treg cells in the blood, spleen, and lungs were determined via flow cytometry. The levels of the cytokines interleukin (IL)-6, IL-17, interferon (IFN)-γ, and transforming growth factor (TGF)-β were detected via enzyme-linked immunosorbent assay. Ifnγ, IL17a, Rorγt and Foxp3 transcription levels were detected via polymerase chain reaction.

Results

CD40+ mDCs accumulated in the lungs of EP-stimulated mice. Blocking the CD40-CD40L pathway with an anti-CD40 antibody alleviated Th1 and Th17 responses; increased the proportion of Treg cells; decreased MLI and DI; reduced the levels of cytokines IL-6, IL-17, and IFN-γ as well as the transcription levels of Ifnγ, IL17a, and Rorγt; and upregulated the expression of TGF-β and Foxp3.

Conclusion

The CD40-CD40L pathway could play a critical role in Th1, Th17 and Treg cell dysregulation in EP-mediated emphysema and could be a potential therapeutic target.

Subclinical cardiovascular outcomes of acute exposure to fine particulate matter and its constituents: A glutathione S-transferase polymorphism-based longitudinal study

To explore the acute subclinical cardiovascular effects of fine particulate matter (PM_2.5) and its constituents, a longitudinal study with 61 healthy young volunteers was conducted in Xinxiang, China. Linear mixed-effect models were used to analyze the association of PM_2.5 and its constituents with cardiovascular outcomes, respectively, including blood pressure (BP), heart rate (HR), serum levels of high-sensitivity C-reactive protein (hs-CRP), 8-hydroxy-2'-deoxyguanosine (8-OHdG), tissue-type plasminogen activator (t-PA), and platelet-monocyte aggregation (PMA). Additionally, the modifying effects of glutathione S-transferase mu 1 (GSTM1) and glutathione S-transferase theta 1 (GSTT1) polymorphisms were examined. A 10 μg/m³ increase in PM_2.5 was associated with -1.04 (95 % CI: -1.86 to -0.22) mmHg and -0.90 (95 % CI: -1.69 to -0.11) mmHg decreases in diastolic BP (DBP) and mean arterial BP (MABP) along with 1.83 % (95 % CI: 0.59-3.08 %), 5.93 % (95 % CI: 0.70-11.16 %) increases in 8-OHdG and hs-CRP, respectively. Ni content was positively associated with the 8-OHdG levels whereas several other metals presented negative association with 8-OHdG and HR. Intriguingly, GSTT1+/GSTTM1+ subjects showed higher susceptibility to PM_2.5-induced alterations of DBP and PMA, and GSTT1-/GSTM1+ subjects showed higher alteration on t-PA. Taken together, our findings indicated that short-term PM_2.5 exposure induced oxidative stress, systemic inflammation, autonomic alterations, and fibrinolysis in healthy young subjects. Among multiple examined metal components Ni appeared to positively associated with systematic oxidative stress. In addition, GST-sufficient subjects might be more prone to PM_2.5-induced autonomic alterations.

Effect of smoking on clinical outcomes in patients receiving rotational atherectomy in calcified coronary lesions: from the ROCK Registry, South Korea

BACKGROUND

Tobacco smoking and its harmful health effects also increase economic burdens globally. Surprisingly, despite the detrimental health consequences of smoking, some studies have shown better survival among smokers compared with non-smokers, a phenomenon called "smoker's paradox". However, the impact of smoking status on clinical outcomes in severe calcified coronary artery disease (CAD) patients has yet to be reported.

OBJECTIVES

Investigate the impact of smoking on clinical outcomes in calcified CAD receiving rotational atherectomy (RA).

DESIGN

Retrospective review of medical records.

SETTING

Multicenter registry in South Korea.

PATIENTS AND METHODS

This multicenter registry included consecutive patients with calcified CAD who underwent RA at nine tertiary centers in Korea between January 2010 and October 2019.

MAIN OUTCOME MEASURES

Target-vessel failure (TVF) which included the composite of cardiac death, target-vessel myocardial infarction (TVMI), and target-vessel revascularization (TVR).

SAMPLE SIZE

583 lesions in 540 patients followed for a median of 16.1 months.

RESULTS

Lesions were divided into two groups: non-smokers (n=472, 81.0%) and smokers (n=111, 19.0%). TVF in the smoker group was significantly more frequent than in non-smoker group (log rank P=.016). The inverse probability of treatment weighting analysis also showed that smoking was significantly associated with a higher incidence of the primary outcome (HR: 1.617; 95% CI: 1.127-2.320; P=.009), cardiac death (HR 1.912; 95% CI: 1.105-3.311; P=.021), myocardial infarction (HR: 3.914; 95% CI: 1.884-8.132; P<.001), TVMI (HR: 3.234; 95% CI: 1.130-9.258; P=.029), and TVR (HR: 1.661; 95% CI: 1.043-2.643; P=.032). However, any bleeding was significantly observed less in the smokers.

CONCLUSION

Smoking is significantly associated with adverse clinical outcomes in CAD patients requiring RA.

LIMITATIONS

Retrospective design.

CONFLICTS OF INTEREST

None.

NOS1-mediated macrophage and endothelial cell interaction in the progression of atherosclerosis

Atherosclerosis is a chronic inflammatory disease arising due to an imbalance in lipid metabolism and maladaptive immune response driven by the accumulation of cholesterol-laden macrophages in the artery wall. Interactions between monocytes/macrophages and endothelial cells play an essential role in the pathogenesis of atherosclerosis. In our current study, nitric oxide synthase 1 (NOS1)-derived nitric oxide (NO) has been identified as a regulator of macrophage and endothelial cell interaction. Oxidized LDL (OxLDL) activates NOS1, which results in the expression of CD40 ligand in macrophages. OxLDL-stimulated macrophages produce some soluble factors which increase the CD40 receptor expression in endothelial cells. This increases the interaction between the macrophages and endothelial cells, which leads to an increase in the inflammatory response. Inhibition of NOS1-derived NO might serve as an effective strategy to reduce foam cell formation and limit the extent of atherosclerotic plaque expansion.

Platelets in Healthy and Disease States: From Biomarkers Discovery to Drug Targets Identification by Proteomics

Platelets are a heterogeneous small anucleate blood cell population with a central role both in physiological haemostasis and in pathological states, spanning from thrombosis to inflammation, and cancer. Recent advances in proteomic studies provided additional important information concerning the platelet biology and the response of platelets to several pathophysiological pathways. Platelets circulate systemically and can be easily isolated from human samples, making proteomic application very interesting for characterizing the complexity of platelet functions in health and disease as well as for identifying and quantifying potential platelet proteins as biomarkers and novel antiplatelet therapeutic targets. To date, the highly dynamic protein content of platelets has been studied in resting and activated platelets, and several subproteomes have been characterized including platelet-derived microparticles, platelet granules, platelet releasates, platelet membrane proteins, and specific platelet post-translational modifications. In this review, a critical overview is provided on principal platelet proteomic studies focused on platelet biology from signaling to granules content, platelet proteome changes in several diseases, and the impact of drugs on platelet functions. Moreover, recent advances in quantitative platelet proteomics are discussed, emphasizing the importance of targeted quantification methods for more precise, robust and accurate quantification of selected proteins, which might be used as biomarkers for disease diagnosis, prognosis and therapy, and their strong clinical impact in the near future.

Short time exposure to ambient ozone and associated cardiovascular effects: A panel study of healthy young adults

The evidence that exposure to ambient ozone (O₃) causes acute cardiovascular effects appears inconsistent. A repeated-measure study with 61 healthy young volunteers was conducted in Xinxiang, Central China. Real-time concentrations of O₃ were monitored. Cardiovascular outcomes including blood pressure (BP), heart rate (HR), serum levels of high sensitivity C-reactive protein (hs-CRP), 8-hydroxy-2'-deoxyguanosine (8-OHdG), tissue-type plasminogen activator (t-PA), and platelet-monocyte aggregation (PMA) were repeated measured. Linear mixed-effect models were used to analyze the association of ambient O₃ with these cardiovascular outcomes. Additionally, the modifying effects of glutathione S-transferase mu 1 (GSTM1) and glutathione S-transferase theta 1 (GSTT1) polymorphisms were estimated to explore the potential mechanisms and role of the association between O₃ exposure and the above cardiovascular outcomes. A 10 μg/m³ increase in O₃ was associated with increases of 9.2 mmHg (95% confidence interval [CI]: 2.5, 15.9), 7.2 mmHg (95% CI: 0.8, 13.6), and 21.2 bpm (95% CI: 5.8, 36.6) in diastolic BP (DBP, lag1), mean arterial BP (MABP, lag1), and HR (lag01), respectively. Meanwhile, the serum concentrations of hs-CRP, 8-OHdG, and t-PA were all increased by O₃ exposure, but the PMA level was decreased. Stratification analyses showed that the estimated effects of O₃ on DBP, MABP, and HR in GSTM1-sufficient subjects were significantly higher than in GSTM1-null subjects. Moreover, GSTM1-null genotype enhanced O₃-induced increases, albeit insignificant, in levels of serum hs-CRP, 8-OHdG, and t-PA compared with GSTM1-sufficient genotype. Insignificant increases in hs-CRP and t-PA were also detected in GSTT1-null subjects. Taken together, our findings indicate that acute exposure to ambient O₃ induces autonomic alterations, systemic inflammation, oxidative stress, and fibrinolysis in healthy young subjects. GSTM1 genotype presents the trend of modifying O₃-induced cardiovascular effects.

Effects of cigarette smoking on older chinese men treated with clopidogrel monotherapy or aspirin monotherapy: a prospective study

We investigated the comparative effects of smoking status on outcomes in older Chinese men receiving aspirin or clopidogrel monotherapy. This was a prospective observational study of outcomes in 668 men aged ≥ 60 years undergoing annual health examination in the Chinese People's Liberation Army General Hospital from March-April 2017. All patients received regular treatment with aspirin or clopidogrel. Platelet aggregation and phenotyping for rs762551 were measured in all patients. We recorded all major adverse cardiovascular and cerebrovascular events; namely, all-cause death, myocardial infarction, stroke, transient ischemic attack, and unstable angina. In the clopidogrel subgroup, homozygous carriers (AA) of the CYP1A2*1F gene (rs762551, 163C>A) appeared more frequently in smokers than in nonsmokers (45.6% vs 32.7%, p = .035). Adenosine diphosphate-induced platelet aggregation using light transmittance aggregometry was lower in smokers compared with nonsmokers (44.97 ± 20.05% vs 51.98 ± 19.38%, respectively; p = .0018). Smokers (n = 103) had a decreased risk of major adverse cardiovascular and cerebrovascular events, compared with nonsmokers [n = 159; hazard ratio, 0.466; 95% confidence interval: 0.262-0.829, p = .008]. In the aspirin subgroup, AA-induced platelet aggregation showed no significant difference regarding smoking vs nonsmoking status (30.90 ± 32.21 vs 29.78 ± 31.47, respectively; p = .771). However, we saw a significant increase in adverse clinical events in the smoking group (n = 148) compared with the nonsmoking group (n = 258; hazard ratio = 1.907, 95% confidence interval: 1.128-3.225; p = .016). In older Chinese men, active smokers benefitted from clopidogrel therapy compared with aspirin. Long-term cigarette smoking may contribute to increased variations in CYP1A2*1F, but the variations do not fully explain the smoking paradox.

Cardiovascular injury induced by tobacco products: assessment of risk factors and biomarkers of harm. A Tobacco Centers of Regulatory Science compilation

Although substantial evidence shows that smoking is positively and robustly associated with cardiovascular disease (CVD), the CVD risk associated with the use of new and emerging tobacco products, such as electronic cigarettes, hookah, and heat-not-burn products, remains unclear. This uncertainty stems from lack of knowledge on how the use of these products affects cardiovascular health. Cardiovascular injury associated with the use of new tobacco products could be evaluated by measuring changes in biomarkers of cardiovascular harm that are sensitive to the use of combustible cigarettes. Such cardiovascular injury could be indexed at several levels. Preclinical changes contributing to the pathogenesis of disease could be monitored by measuring changes in systemic inflammation and oxidative stress, organ-specific dysfunctions could be gauged by measuring endothelial function (flow-mediated dilation), platelet aggregation, and arterial stiffness, and organ-specific injury could be evaluated by measuring endothelial microparticles and platelet-leukocyte aggregates. Classical risk factors, such as blood pressure, circulating lipoproteins, and insulin resistance, provide robust estimates of risk, and subclinical disease progression could be followed by measuring coronary artery Ca2+ and carotid intima-media thickness. Given that several of these biomarkers are well-established predictors of major cardiovascular events, the association of these biomarkers with the use of new and emerging tobacco products could be indicative of both individual and population-level CVD risk associated with the use of these products. Differential effects of tobacco products (conventional vs. new and emerging products) on different indexes of cardiovascular injury could also provide insights into mechanisms by which they induce cardiovascular harm.

Periodontitis and mechanisms of cardiometabolic risk: Novel insights and future perspectives

Periodontitis is an infectious and inflammatory disease of the tooth-supporting tissues caused by the accumulation of subgingival plaque and the action of specific periodontopathogenic bacteria. Periodontitis has been associated with cardiovascular diseases and considered a cardiovascular risk factor. Several mechanisms have been proposed to explain this association, such as the infection of atherosclerotic plaques by periodontal pathogens, the pro-atherogenic effect on the lipid profile, the systemic dissemination of pro-inflammatory mediators or the contribution to type 2 diabetes mellitus. Periodontal treatment has also been related to improvement in cardiometabolic risk variables, and oral hygiene techniques may be useful in reducing cardiometabolic risk. The aim of this review is to provide new and recent insights on the relationship between periodontitis and cardiometabolic risk, focusing on recent evidence. Comments on shared potential therapeutic targets, such as the role of glucagon-like peptide 1, are also highlighted.

Extracellular Matrix Metalloproteinase Inducer EMMPRIN (CD147) in Cardiovascular Disease

The receptor EMMPRIN is involved in the development and progression of cardiovascular diseases and in the pathogenesis of myocardial infarction. There are several binding partners of EMMPRIN mediating the effects of EMMPRIN in cardiovascular diseases. EMMPRIN interaction with most binding partners leads to disease progression by mediating cytokine or chemokine release, the activation of platelets and monocytes, as well as the formation of monocyte-platelet aggregates (MPAs). EMMPRIN is also involved in atherosclerosis by mediating the infiltration of pro-inflammatory cells. There is also evidence that EMMPRIN controls energy metabolism of cells and that EMMPRIN binding partners modulate intracellular glycosylation and trafficking of EMMPRIN towards the cell membrane. In this review, we systematically discuss these multifaceted roles of EMMPRIN and its interaction partners, such as Cyclophilins, in cardiovascular disease.

Soluble CD40 Ligand and Oxidative Response Are Reciprocally Stimulated during Shiga Toxin-Associated Hemolytic Uremic Syndrome

Shiga toxin (Stx), produced by Escherichia coli, is the main pathogenic factor of diarrhea-associated hemolytic uremic syndrome (HUS), which is characterized by the obstruction of renal microvasculature by platelet-fibrin thrombi. It is well known that the oxidative imbalance generated by Stx induces platelet activation, contributing to thrombus formation. Moreover, activated platelets release soluble CD40 ligand (sCD40L), which in turn contributes to oxidative imbalance, triggering the release of reactive oxidative species (ROS) on various cellular types. The aim of this work was to determine if the interaction between the oxidative response and platelet-derived sCD40L, as consequence of Stx-induced endothelium damage, participates in the pathogenic mechanism during HUS. Activated human glomerular endothelial cells (HGEC) by Stx2 induced platelets to adhere to them. Although platelet adhesion did not contribute to endothelial damage, high levels of sCD40L were released to the medium. The release of sCD40L by activated platelets was inhibited by antioxidant treatment. Furthermore, we found increased levels of sCD40L in plasma from HUS patients, which were also able to trigger the respiratory burst in monocytes in a sCD40L-dependent manner. Thus, we concluded that platelet-derived sCD40L and the oxidative response are reciprocally stimulated during Stx2-associated HUS. This process may contribute to the evolution of glomerular occlusion and the microangiopathic lesions.

Oxidative Stress and Cardiovascular Risk: Obesity, Diabetes, Smoking, and Pollution: Part 3 of a 3-Part Series

Oxidative stress occurs whenever the release of reactive oxygen species (ROS) exceeds endogenous antioxidant capacity. In this paper, we review the specific role of several cardiovascular risk factors in promoting oxidative stress: diabetes, obesity, smoking, and excessive pollution. Specifically, the risk of developing heart failure is higher in patients with diabetes or obesity, even with optimal medical treatment, and the increased release of ROS from cardiac mitochondria and other sources likely contributes to the development of cardiac dysfunction in this setting. Here, we explore the role of different ROS sources arising in obesity and diabetes, and the effect of excessive ROS production on the development of cardiac lipotoxicity. In parallel, contaminants in the air that we breathe pose a significant threat to human health. This paper provides an overview of cigarette smoke and urban air pollution, considering how their composition and biological effects have detrimental effects on cardiovascular health.

Aortic Wall Inflammation Predicts Abdominal Aortic Aneurysm Expansion, Rupture, and Need for Surgical Repair

Supplemental Digital Content is available in the text.

Background:

Ultrasmall superparamagnetic particles of iron oxide (USPIO) detect cellular inflammation on magnetic resonance imaging (MRI). In patients with abdominal aortic aneurysm, we assessed whether USPIO-enhanced MRI can predict aneurysm growth rates and clinical outcomes.

Methods

In a prospective multicenter open-label cohort study, 342 patients with abdominal aortic aneurysm (diameter ≥40 mm) were classified by the presence of USPIO enhancement and were monitored with serial ultrasound and clinical follow-up for ≥2 years. The primary end point was the composite of aneurysm rupture or repair.

Results

Participants (85% male, 73.1±7.2 years) had a baseline aneurysm diameter of 49.6±7.7 mm, and USPIO enhancement was identified in 146 (42.7%) participants, absent in 191 (55.8%), and indeterminant in 5 (1.5%). During follow-up (1005±280 days), 17 (5.0%) abdominal aortic aneurysm ruptures, 126 (36.8%) abdominal aortic aneurysm repairs, and 48 (14.0%) deaths occurred. Compared with those without uptake, patients with USPIO enhancement have increased rates of aneurysm expansion (3.1±2.5 versus 2.5±2.4 mm/year, P=0.0424), although this was not independent of current smoking habit (P=0.1993). Patients with USPIO enhancement had higher rates of aneurysm rupture or repair (47.3% versus 35.6%; 95% confidence intervals, 1.1–22.2; P=0.0308). This finding was similar for each component of rupture (6.8% versus 3.7%, P=0.1857) or repair (41.8% versus 32.5%, P=0.0782). USPIO enhancement was associated with reduced event-free survival for aneurysm rupture or repair (P=0.0275), all-cause mortality (P=0.0635), and aneurysm-related mortality (P=0.0590). Baseline abdominal aortic aneurysm diameter (P<0.0001) and current smoking habit (P=0.0446) also predicted the primary outcome, and the addition of USPIO enhancement to the multivariate model did not improve event prediction (c-statistic, 0.7935–0.7936).

Conclusions

USPIO-enhanced MRI is a novel approach to the identification of aortic wall cellular inflammation in patients with abdominal aortic aneurysms and predicts the rate of aneurysm growth and clinical outcome. However, it does not provide independent prediction of aneurysm expansion or clinical outcomes in a model incorporating known clinical risk factors.

Clinical Trial Registration:

URL: http://www.isrctn.com. Unique identifier: ISRCTN76413758.

The potential role of endothelial dysfunction and platelet activation in the development of thrombotic risk in COPD patients

INTRODUCTION

Despite lack of knowledge in the field, several studies have underlined the role of endothelium dysfunction and platelet activation as significant players in the development and progression of chronic obstructive pulmonary disease (COPD). Indeed, endothelium plays a crucial role in vascular homeostasis and impairment, due to the inflammation process enhanced by smoking. Chronic inflammation and endothelial dysfunction have been proved to drive platelet activity. Consequently, thrombotic risk is enhanced in COPD, and might explain the higher percentage of cardiovascular death in such patients. Areas covered: This review aims to clarify the role of endothelium function and platelet hyper-activity as the pathophysiological mechanisms of the increased thrombotic risk in COPD. Expert commentary: In COPD patients, chronic inflammation does not impact only on lung parenchyma, but potentially involves all systems, including the endothelium of blood vessels. Impaired endothelium has several consequences, such as reduced vasodilatation capacity, enhanced blood coagulation, and increased platelet activation resulting in higher risk of thrombosis in COPD patients. Endothelium dysfunction and platelet activation are potential targets of therapy in patients with COPD aiming to reduce their risk of cardiovascular events.

Pooled Analysis Comparing the Efficacy of Intracoronary Versus Intravenous Abciximab in Smokers Versus Nonsmokers Undergoing Primary Percutaneous Coronary Revascularization for Acute ST-Elevation Myocardial Infarction

Cigarette smokers with ST-segment elevation myocardial infarction (STEMI) may present different response to potent antithrombotic therapy compared to nonsmokers. We assessed the impact of smoking status and intracoronary abciximab in patients with STEMI undergoing primary percutaneous coronary intervention (PCI). We pooled data from 5 randomized trials comparing intracoronary versus intravenous abciximab bolus in patients undergoing primary PCI. The primary end point was the composite of death or reinfarction at a mean follow-up of 292 ± 138 days. Of 3,158 participants, 1,369 (43.3%) were smokers, and they had a lower risk of the primary end point in crude, but not in adjusted analyses (hazard ratio [HR] 0.87, 95% confidence interval [CI] 0.63 to 1.21, p = 0.405). Intracoronary versus intravenous abciximab was associated with a significant reduction in the risk of primary end point among smokers (3.6% vs 8.0%; HR 0.43, 95% CI 0.26 to 0.72, p = 0.001), but not in nonsmokers (10.2% vs 9.9%; HR 0.99, 95% CI 0.72 to 1.36, p = 0.96), with a significant interaction (p = 0.009). Furthermore, intracoronary abciximab decreased the risk of reinfarction in smokers (HR 0.30, 95% CI 0.15 to 0.62, p = 0.001), with no difference in nonsmokers (HR 1.20, 95% CI 0.71 to 2.01, p = 0.50). Stent thrombosis was lowered by intracoronary abciximab in smokers (HR 0.28, 95% CI 0.06 to 0.66, p = 0.009), but was ineffective in nonsmokers (HR 1.04, 95% CI 0.54 to 2.00, p = 0.903). Interaction testing showed heterogeneity in treatment effect for reinfarction (p = 0.002) and stent thrombosis (p = 0.018) according to smoking status. In conclusion, among patients with STEMI undergoing primary PCI, smoking status did not affect the adjusted risk of clinical events. Intracoronary abciximab bolus improved clinical outcomes by reducing the risk of death or reinfarction.

Smoking as a contributing factor for development of polycythemia vera and related neoplasms

Smoking may be associated with accelerated erythropoiesis, leukocytosis and thrombocytosis, which are also hallmarks in patients with polycythemia vera, essential thrombocythemia and early stages of myelofibrosis (MPNs). The JAK-STAT and NF-κB signaling pathways are activated in both smokers and in patients with MPNs. Additionally, both share elevated levels of several proinflammatory cytokines, in vivo activation of leukocytes and platelets, endothelial dysfunction and increased systemic oxidative stress. Based upon experimental, epidemiological and clinical data it is herein argued and discussed, if smoking may be involved in MPN pathogenesis, considering most recent studies and reviews which are supportive of the concept that chronic inflammation with NF-κB activation and oxidative stress may have a major role - both as triggers but also as the driving force for clonal expansion in MPNs.

A review on thromboangiitis obliterans pathophysiology: thrombosis and angiitis, which is to blame?

A century has passed since thromboangiitis obliterans (TAO), or Buerger's disease, was first described, but the etiology remains unclear. It is still uncertain as to whether thrombosis or vascular inflammation is the first event. TAO is an episodic inflammatory and thrombotic-occlusive vascular disease of unknown origin. The involvement of the distal vessels and nerves within the neuro-vascular bundles occurs almost always in legs and occasionally in arms. The cumulative data demonstrate that at the cellular and molecular levels, at least four main components of inflammatory reactions, including endothelial cells, platelets, leukocytes and sensory neurons, might be involved in TAO pathogenesis. The interactions among these cells in an altered microenvironment of small- and medium-sized vessels may also orchestrate the onset of TAO events. In this review, the factors that may promote thrombosis and angiitis are reconsidered at three levels: (1) host characteristics such as male gender and genetic background; (2) probable triggers including cigarette smoking and infectious agents; and (3) environmental factors such as chronic anxiety and mental stress as a consequence of low socioeconomic status. At each level, the interactions among vascular endothelium, platelets, leukocytes and sensory neurons are discussed.

Monocyte CD40 expression in young healthy female smokers and/or oral contraceptives users without additional risk factors for atherosclerosis

OBJECTIVE

Atherosclerosis, as an inflammatory disease, is characterized by pathologically altered levels of cytokines. We investigated whether smoking and/or oral contraceptives (OCs) affect the CD40/CD40L plasma levels and expression in young females without other risk factors for atherosclerosis.

PATIENTS AND METHODS

A case-control single-center design was used. Expression levels of CD40/CD40L were analyzed in healthy non-pregnant, pre-menopausal, non-smoking women who did not take OCs (n=49), women who currently smoke and take OCs (n=40), and women who are only smokers (n=40) or currently take OCs (n=42).

RESULTS

In OC users, there was a significant increase in CD40 mRNA expression in circulating monocytes as compared with smokers and control group. However, there were no significant differences in CD40 mRNA expression in monocytes between smokers and non-smokers. Interestingly, CD40 mRNA expression in women taking OCs and currently smoking was significantly decreased compared to only OC users (p<0.001). With regard to plasma CD40 levels there were significant differences between OC-users and control group. However, contrary to our expectations, there were no significant differences in expression levels of CD40L between four groups. In vitro experiments demonstrated enhanced CD40 mRNA and surface expression in human monocyte-derived macrophages stimulated with estrogens. Furthermore, nicotine pretreatment led to a suppression of estrogens stimulated CD40 induction.

CONCLUSIONS

In young healthy females without additional risk factors for atherosclerosis, OCs, but not smoking, are associated with dramatic changes in CD40 gene and plasma levels. These findings may be providing an important link between OCs and enhancement of pro-inflammatory and atherothrombotic conditions in healthy women.

Impact of smoking status on platelet function and clinical outcomes with prasugrel vs. clopidogrel in patients with acute coronary syndromes managed without revascularization: Insights from the TRILOGY ACS trial

BACKGROUND

To further explore the impact of smoking on antiplatelet activity and treatment response, we evaluated time-dependent relationships between smoking status with on-treatment platelet reactivity and clinical outcomes for prasugrel vs. clopidogrel in patients with acute coronary syndromes managed medically without revascularization.

METHODS AND RESULTS

A total of 7062 patients aged <75 years from the primary TRILOGY ACS cohort randomized to prasugrel vs. clopidogrel were evaluated through 30 months by baseline and time-dependent smoking status with adjusted proportional-hazards models. A total of 1994 participants (28%) [corrected] were included in a platelet function sub-study evaluating serial P2Y12 reaction unit (PRU) measurements. Current smokers (n = 1566 [22%]) at baseline had fewer comorbidities compared with non-smokers; nearly half quit smoking during follow-up. Although median on-treatment PRU values were lower with prasugrel vs. clopidogrel, persistent smokers had lower serial PRU values in both treatment groups compared with non-smokers, with no differential interaction of treatment response by smoking status. The frequency of cardiovascular death, myocardial infarction, or stroke in current smokers was significantly lower with prasugrel (11.7%) vs. clopidogrel (18.6%), but there was no difference in non-smokers (13.8% vs. 13.7%), with significant interaction between treatment and baseline smoking status (P = .0002). Bleeding events occurred more frequently in prasugrel-treated patients with no significant interaction between treatment and baseline smoking status.

CONCLUSIONS

Among medically managed ACS patients <75 years of age, the risk of ischemic outcomes was significantly reduced with prasugrel vs. clopidogrel among smokers vs. non-smokers. No interaction between on-treatment platelet reactivity and smoking status was found.

Platelet activation as a novel mechanism of atherothrombotic risk in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by pulmonary and systemic inflammation. In particular, the clinical course of this disease typically leads to periodic exacerbation involving inflammatory response and both respiratory and cardiovascular symptoms. Even though the exact mechanisms underlying the pathogenesis of COPD and its chronic and acute inflammation have not yet been fully understood, many studies have been highlighting the role of the endothelium, platelets (PTL) and other circulating blood cells. PLT are crucial for hemostasis and, once activated by a number of different factors, will mediate endothelium adhesion, and the rolling and activation of other circulating cells, such as neutrophils, which become a cause of tissue damage during the inflammatory process. The aim of this review is to highlight the onset of activation, thrombus formation and inflammatory amplification with particular regard to the COPD patients and the course of their acute exacerbations.

Increased proatherogenic monocyte-platelet cross-talk in monocyte subpopulations of patients with stable coronary artery disease

BACKGROUND

Monocytes and platelets are important cellular mediators of atherosclerosis. Human monocytes can be divided into CD14(++) CD16(-) , CD14(++) CD16(+) and CD14(+) CD16(++) cells, which differ in their functional properties. The aim of this study was to examine monocyte subset distribution, monocyte-platelet aggregate (MPA) formation and expression of CCR5, the receptor of the platelet-derived chemokine CCL5, and to determine whether these parameters are altered in individuals with coronary atherosclerosis.

METHODS

Peripheral blood cells from 64 healthy blood donors (HBDs) and 60 patients with stable coronary artery disease (CAD) were stained with antibodies against CD14, CD16, CD42b and CCR5 and analysed by flow cytometry. Circulating CCL5 levels were determined using an enzyme-linked immunosorbent assay.

RESULTS

In patients with CAD, the relative proportion of the CD14(++) CD16(-) monocyte subset was elevated (P < 0.05) and of the CD14(+) CD16(++) subset was reduced (P < 0.001) compared with the HBD group. Furthermore, MPA formation significantly increased in patients with CAD in all three monocyte subsets. In both study groups, the majority of CCR5(+) cells was detected in CD14(++) CD16(+) monocytes (P < 0.001 versus CD14(++) CD16(-) and CD14(+) CD16(++) ), although the CCR5(+) monocyte number was reduced in patients with CAD (CD14(++) CD16(-) /CD14(+) CD16(++) , P < 0.001; CD14(++) CD16(+) , P < 0.05) compared with the HBD group, particularly in those who were not taking statins. Ex vivo incubation of monocytes from HBDs with plasma from patients with CAD also decreased CCR5(+) expression (P < 0.05 versus plasma from HBDs). Serum CCL5 levels were similar in both groups.

CONCLUSIONS

The increased monocyte-platelet cross-talk in patients with CAD might have contributed to atherosclerosis progression. The decreased CCR5(+) monocyte numbers in patients with CAD could have resulted from CCR5(+) cell recruitment into atherosclerotic lesions or CCR5 downregulation in response to circulating factors.

Cardiovascular disease in COPD: mechanisms

It is now well established that cardiovascular disease contributes significantly to both morbidity and mortality in COPD. Shared risk factors for cardiovascular disease and COPD, such as smoking, low socioeconomic class, and a sedentary lifestyle contribute to the natural history of each of these conditions. However, it is now apparent that alternative, novel mechanisms are involved in the pathogenesis of cardiovascular disease, and these may play an important role in driving the increased cardiovascular risk associated with COPD. In this article, we discuss the potential mechanisms that link COPD to an increased risk of cardiovascular disease.

Heritability, genetic correlation and linkage to the 9p21.3 region of mixed platelet-leukocyte conjugates in families with and without early myocardial infarction

BACKGROUND AND AIMS

Variations in mixed platelet-leukocyte conjugate formation in human whole blood could be genetically determined. We quantified platelet and leukocyte activation and interaction in families with or without early myocardial infarction and evaluated their heritability, genetic correlation and linkage to the 9p21.3 region.

METHODS AND RESULTS

The study population included 739 subjects (≥ 15 years old) from 54 large pedigrees, 23 with and 31 without familial myocardial infarction. Mixed platelet-leukocyte conjugates and markers of platelet or leukocyte activation (P-selectin, CD11b and L-selectin surface expression) were measured both before and after in vitro blood stimulation with collagen-ADP. All traits had significant genetic components (17.5-65.3% of the phenotypic variability), while shared household effects (0-39.6%) and environmental covariates (0-10.2%) tended to be smaller. Stimulated platelet-polymorphonuclear leukocyte (PMN) and platelet-monocyte conjugates showed the highest linkage to the 9p21.3 region (LOD = 0.94 and 1.33, respectively; empirical p value = 0.017 and 0.009). PMN markers resulted strongly genetically correlated between them in bivariate analysis among pairs of quantitative traits.

CONCLUSION

This study supports a genetic regulation of human mixed platelet-leukocyte conjugates.

Cardiovascular effects of a novel SIRT1 activator, SRT2104, in otherwise healthy cigarette smokers

BACKGROUND

We examined the effect of the oral SIRT1 activator SRT2104 on cardiovascular function in otherwise healthy cigarette smokers.

METHODS AND RESULTS

Twenty-four otherwise healthy cigarette smokers participated in a randomized double-blind, placebo-controlled crossover trial and received 28 days of oral SRT2104 (2.0 g/day) or matched placebo. Plasma SRT2104 concentrations, serum lipid profile, plasma fibrinolytic factors, and markers of platelet and monocyte activation were measured at baseline and at the end of each treatment period together with an assessment of forearm blood flow during intra-arterial bradykinin, acetylcholine, and sodium nitroprusside infusions. Three hours postdose, mean plasma SRT2104 concentration was 1328 ± 748 ng/mL after 28 days of active treatment. Compared with placebo, serum lipid profile improved during SRT2104 administration, with reductions in serum total cholesterol (-11.6 ± 20 versus 6 ± 21 mg/dL), low-density lipoprotein cholesterol (-10 ± 17 versus 3 ± 21 mg/dL), and triglyceride (-39.8 ± 77 versus 13.3 ± 57 mg/dL) concentrations (P<0.05 for all). All vasodilators produced a dose-dependent increase in blood flow (P<0.0001) that was similar during each treatment period (P>0.05 for all). No significant differences in fibrinolytic or blood flow parameters were observed between placebo and SRT2014.

CONCLUSIONS

SRT2104 appears to be safe and well tolerated and associated with an improved lipid profile without demonstrable differences in vascular or platelet function in otherwise healthy cigarette smokers.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov. Unique identifier: NCT01031108.

Pharmacological control of platelet-leukocyte interactions by the human anti-P-selectin antibody inclacumab--preclinical and clinical studies

BACKGROUND AND OBJECTIVE

Elevated levels of platelet-leukocyte aggregates (PLAs) have been reported in several cardiovascular diseases and suggested to contribute to disease pathology. Our aim was to characterize the effects of inclacumab, a novel human anti-P-selectin antibody, on the interactions between leukocytes and platelets in preclinical and clinical studies.

EXPERIMENTAL APPROACHES

Dual-label flow cytometry was used to detect the effect of inclacumab on agonist-induced platelet-leukocyte/platelet-monocyte aggregates in cynomolgus monkeys and humans, following ex vivo and in vivo administration. Platelet-dependent leukocyte activation and leukocyte adhesion to a platelet monolayer were also investigated after ex vivo administration of inclacumab to human blood.

RESULTS

Treatment of cynomolgus monkeys with inclacumab profoundly inhibited thrombin receptor-activating peptide (TRAP) or adenosine diphosphate (ADP)-induced PLAs with an IC50 (<2 μg/mL) similar to the in vitro spiking experiments. Maximal inhibition of PLAs persisted for ≥28 days following single dose of inclacumab. In human blood, inclacumab was about 2-fold more potent in inhibiting TRAP-induced PLAs (IC50: 0.7 μg/mL) compared to monkeys. PLA formation was suppressed independently of the inducing platelet agonist. Inclacumab also inhibited the activation of the leukocyte integrin Mac-1 and leukocyte adhesion to a platelet monolayer under flow conditions. In clinical studies, inclacumab inhibited TRAP-induced PLA formation in a dose-dependent manner following single and multiple dose administration to healthy volunteers. It also reduced elevated circulating PLA levels in patients with peripheral arterial disease.

CONCLUSION

By inhibiting platelet-leukocyte interactions, demonstrated in multiple preclinical and clinical studies, inclacumab may provide an effective treatment for cardiovascular diseases.

The biology behind the atherothrombotic effects of cigarette smoke

Cigarette smoke is an aerosol that contains >4,000 chemicals, including nicotine, carbon monoxide, acrolein, and oxidant compounds. Exposure to cigarette smoke induces multiple pathological effects in the endothelium, several of which are the result of oxidative stress initiated by reactive oxygen species, reactive nitrogen species, and other oxidant constituents of cigarette smoke. Cigarette-smoke exposure interferes adversely with the control of all stages of plaque formation and development and pathological thrombus formation. The reactive oxygen species in cigarette smoke contribute to oxidative stress, upregulation of inflammatory cytokines, and endothelial dysfunction, by reducing the bioavailability of nitric oxide. Plaque formation and the development of vulnerable plaques also result from exposure to cigarette smoke via the enhancement of inflammatory processes and the activation of matrix metalloproteases. Moreover, exposure to cigarette smoke results in platelet activation, stimulation of the coagulation cascade, and impairment of anticoagulative fibrinolysis. Many cigarette-smoke-mediated prothrombotic changes are quickly reversible upon smoking cessation. Public health efforts should urgently promote our understanding of current cigarette-smoke-induced cardiovascular pathology to encourage individuals to reduce their exposure to cigarette smoke and, therefore, the detrimental consequences of associated atherothrombotic disease.

Effect of PSI-697, a novel P-selectin inhibitor, on platelet-monocyte aggregate formation in humans

Background

Platelet activation is central to the pathogenesis of acute coronary syndromes. Surface expression of P‐selectin on activated platelets induces formation of platelet–monocyte aggregates and promotes vascular inflammation and thrombosis. P‐selectin antagonism may represent a novel therapeutic strategy in vascular disease. We aimed to investigate the effects of the novel P‐selectin antagonist PSI‐697 on platelet–monocyte aggregate formation in humans.

Methods and Results

In a double‐blind, randomized, placebo‐controlled crossover study, healthy smokers were randomized to receive either oral PSI‐697 600 mg or matched placebo. The sequence of treatment was also randomized, with all subjects receiving both PSI‐697 and placebo. Platelet–monocyte aggregates were measured by flow cytometry at 4 and 24 hours in the presence and absence of thrombin receptor‐activating peptide (TRAP; 0.1 to 1.0 μm/L). The ex vivo addition of TRAP caused a concentration‐dependent increase in platelet–monocyte aggregates from 8.2% to 94.8% (P<0.001). At 4 and 24 hours, plasma concentrations of PSI‐697 increased to 1906 and 83 ng/mL, respectively (P<0.001). PSI‐697 had no demonstrable effect on either stimulated or unstimulated platelet–monocyte aggregates at 4 or 24 hours (P>0.05). P‐selectin‐blocking antibody (CLB‐Thromb6), but not PSI‐697, inhibited both stimulated and unstimulated platelet–monocyte aggregate formation in vitro (P<0.001).

Conclusions

The novel small‐molecule P‐selectin antagonist PSI‐697 did not inhibit basal or stimulated platelet–monocyte aggregate formation in humans at the dose tested. Its clinical efficacy remains to be established.

Clinical Trial Registration

URL: http://EudraCT.ema.europa.eu Unique identifier: 2007‐005695‐14.

Prior smoking status, clinical outcomes, and the comparison of ticagrelor with clopidogrel in acute coronary syndromes-insights from the PLATelet inhibition and patient Outcomes (PLATO) trial

BACKGROUND

Habitual smoking has been associated with increased platelet reactivity, increased risk of thrombotic complications and greater efficacy of clopidogrel therapy over placebo. In the PLATO trial, ticagrelor compared to clopidogrel in patients with acute coronary syndromes (ACS) reduced the primary composite end point of vascular death, myocardial infarction and stroke, without increasing overall rates of major bleeding. We evaluated the results in relation to smoking habits.

METHODS

Interactions between habitual smokers (n = 6678) and in ex/nonsmokers (n = 11,932) and the effects of randomized treatments on ischemic and bleeding outcomes were evaluated by Cox regression analyses.

RESULTS

Habitual smokers had an overall lower risk profile and more often ST-elevation ACS. After adjustment for baseline imbalances, habitual smoking was associated with a higher incidence of definite stent thrombosis (adjusted HR, 1.44 [95% CI, 1.07-1.94]); there were no significant associations with other ischemic or bleeding end points. The effects of ticagrelor compared to clopidogrel were consistent for all outcomes regardless of smoking status. Thus, there was a similar reduction in the primary composite end point for habitual smokers (adjusted HR, 0.83 [95% CI, 0.68-1.00]) and ex/nonsmokers (adjusted HR, 0.89 [95% CI, 0.79-1.00]) (interaction P = .50), and in definite stent thrombosis for habitual smokers (adjusted HR, 0.59 [0.39-0.91]) and ex/nonsmokers (adjusted HR, 0.69 [95% CI, 0.45-1.07]) (interaction P = .61).

CONCLUSIONS

In patients hospitalized with ACS, habitual smoking is associated with a greater risk of subsequent stent thrombosis. The reduction of vascular death, myocardial infarction, stroke, and stent thrombosis by ticagrelor compared to clopidogrel is consistent regardless of smoking habits.

CD40 amplifies Fas-mediated apoptosis: a mechanism contributing to emphysema

Excessive apoptosis and prolonged inflammation of alveolar cells are associated with the pathogenesis of pulmonary emphysema. We aimed to determine whether CD40 affects alveolar epithelial cells and endothelial cells, with regard to evoking apoptosis and inflammation. Mice were repeatedly treated with agonistic-anti CD40 antibody (Ab), with or without agonistic-anti Fas Ab, and evaluated for apoptosis and inflammation in lungs. Human pulmonary microvascular endothelial cells and alveolar epithelial cells were treated with agonistic anti-CD40 Ab and/or anti-Fas Ab to see their direct effect on apoptosis and secretion of proinflammatory molecules in vitro. Furthermore, plasma soluble CD40 ligand (sCD40L) level was evaluated in patients with chronic obstructive pulmonary disease (COPD). In mice, inhaling agonistic anti-CD40 Ab induced moderate alveolar enlargement. CD40 stimulation, in combination with anti-Fas Ab, induced significant emphysematous changes and increased alveolar cell apoptosis. CD40 stimulation also enhanced IFN-γ-mediated emphysematous changes, not via apoptosis induction, but via inflammation with lymphocyte accumulation. In vitro, Fas-mediated apoptosis was enhanced by CD40 stimulation and IFN-γ in endothelial cells and by CD40 stimulation in epithelial cells. CD40 stimulation induced secretion of CCR5 ligands in endothelial cells, enhanced with IFN-γ. Plasma sCD40L levels were significantly increased in patients with COPD, inversely correlating to the percentage of forced expiratory volume in 1 s and positively correlating to low attenuation area score by CT scan, regardless of smoking history. Collectively CD40 plays a contributing role in the development of pulmonary emphysema by sensitizing Fas-mediated apoptosis in alveolar cells and increasing the secretion of proinflammatory chemokines.

Thrombopoietin as biomarker and mediator of cardiovascular damage in critical diseases

Thrombopoietin (TPO) is a humoral growth factor originally identified for its ability to stimulate the proliferation and differentiation of megakaryocytes. In addition to its actions on thrombopoiesis, TPO directly modulates the homeostatic potential of mature platelets by influencing their response to several stimuli. In particular, TPO does not induce platelet aggregation per se but is able to enhance platelet aggregation in response to different agonists (“priming effect”). Our research group was actively involved, in the last years, in characterizing the effects of TPO in several human critical diseases. In particular, we found that TPO enhances platelet activation and monocyte-platelet interaction in patients with unstable angina, chronic cigarette smokers, and patients with burn injury and burn injury complicated with sepsis. Moreover, we showed that TPO negatively modulates myocardial contractility by stimulating its receptor c-Mpl on cardiomyocytes and the subsequent production of NO, and it mediates the cardiodepressant activity exerted in vitro by serum of septic shock patients by cooperating with TNF-α and IL-1β. This paper will summarize the most recent results obtained by our research group on the pathogenic role of elevated TPO levels in these diseases and discuss them together with other recently published important studies on this topic.

Current concepts of platelet activation: possibilities for therapeutic modulation of heterotypic vs. homotypic aggregation

Thrombogenic and inflammatory activity are two distinct aspects of platelet biology, which are sustained by the ability of activated platelets to interact with each other (homotypic aggregation) and to adhere to circulating leucocytes (heterotypic aggregation). These two events are regulated by distinct biomolecular mechanisms that are selectively activated in different pathophysiological settings. They can occur simultaneously, for example, as part of a pro-thrombotic/pro-inflammatory response induced by vascular damage, or independently, as in certain clinical conditions in which abnormal heterotypic aggregation has been observed in the absence of intravascular thrombosis. Current antiplatelet drugs have been developed to target specific molecular signalling pathways mainly implicated in thrombus formation, and their ever increasing clinical use has resulted in clear benefits in the treatment and prevention of arterial thrombotic events. However, the efficacy of currently available antiplatelet drugs remains suboptimal, most likely because their therapeutic action is limited to only few of the signalling pathways involved in platelet homotypic aggregation. In this context, modulation of heterotypic aggregation, which is believed to contribute importantly to acute thrombotic events, as well to the pathophysiology of atherosclerosis itself, may offer benefits over and above the classical antiplatelet approach. This review will focus on the distinct biomolecular pathways that, following platelet activation, underlie homotypic and heterotypic aggregation, aiming potentially to identify novel therapeutic targets.

Circulating inflammatory cells are associated with vein graft stenosis

OBJECTIVE

Infrainguinal autogenous vein grafts are especially prone to narrowing and failure, and both inflammatory and thrombotic pathways are implicated. Platelets and monocytes are the key thrombo-inflammatory cells that arrive first at sites of vascular injury. These cells have potent interactions that recruit and activate one another, propagating thrombotic and inflammatory responses within the vessel wall. We therefore hypothesized that elevated levels of platelet-monocyte aggregates (PMA) might be associated with stenosis, and could possibly discriminate between patients with or without vein graft stenosis.

METHODS

Thirty-six vascular surgery patients were studied, in a stable quiescent period after infrainguinal autogenous vein graft bypasses for occlusive disease. Eighteen patients had hemodynamically significant graft stenoses confirmed by imaging, and 18 were free from stenosis. The level of PMA in whole blood was quantified after blood draw using two-color flow cytometry. Three measurements were made per sample: the basal, in-vivo level of aggregates (baseline PMA); the predisposition to spontaneously generate PMA (spontaneous PMA); and PMA generation by the addition of exogenous thrombin receptor-activating peptide (stimulated PMA). The baseline, in-vivo level of PMA was estimated by immediate flow analysis. The predisposition to spontaneously generate PMA was measured after in vitro incubation. Responsiveness to thrombin stimulation of the blood was quantified by the in vitro dose response to an exogenous thrombin receptor-activating peptide (sfllrn).

RESULTS

Baseline PMA levels were similar in patients with vein graft stenosis vs nonstenosis (14.8% ± 3.2 vs 10.1% ± 1.5, respectively, mean ± SEM). However, patients with stenosis showed higher spontaneous PMA levels (58.5% ± 4.5 vs 28.3% ± 4.3; P < .001) and higher stimulated PMA levels (P < .001; analysis of variance). Covariables of smoking, diabetes, statin, or antithrombotic therapy could not account for these differences.

CONCLUSIONS

Platelet-monocyte reactivity may play a role in the development of vein graft stenoses. Those with/without stenosis differed primarily in their threshold, or predisposition to form aggregates (spontaneous PMA), while their basal circulating levels of PMA (baseline PMA) were similar. These measurements may unmask pathologic differences in thrombo-inflammatory responsiveness that are not apparent in basal measurements. Understanding the causes and mechanisms leading to abnormal platelet-monocyte responses may improve approaches to predicting or preventing vein graft stenosis.

The CD40-CD40L system in cardiovascular disease

The CD40-CD40L system is a pathway which is associated with both prothrombotic and proinflammatory effects. CD40 and its ligand were first discovered on the surface of activated T cells, but its presence on B cells, antigen-presenting cells, mast cells, and finally platelets, is evident. The soluble form of CD40L (sCD40L) is derived mainly from activated platelets and contributes to the pathophysiology of atherosclerosis and atherothrombosis. Indeed, sCD40L has autocrine, paracrine, and endocrine activities, and it enhances platelet activation, aggregation, and platelet-leucocyte conjugation that may lead to atherothrombosis. It has even been suggested that sCD40L may play a pathogenic role in triggering acute coronary syndromes. Conversely, blockade of this pathway with anti-CD40L antibodies may prevent or delay the progression of atherosclerosis. Concentrations of sCD40L also predict risk of future cardiovascular disease in healthy women and clinical outcomes in patients with acute coronary syndromes. However, there are controversial and uncertain points over the application of this biomarker to clinical cardiology. In this review, we provide an overview of potential implications of CD40-CD40L signalling and sCD40L as a biomarker in patients with atherosclerotic vascular diseases.

Smoking related diseases: the central role of monoamine oxidase

Smoking is a major risk factor of morbidity and mortality. It is well established that monoamine oxidase (MAO) activity is decreased in smokers. Serotonin (5-HT), a major substrate for MAO that circulates as a reserve pool stored in platelets, is a marker of platelet activation. We recently reported that smoking durably modifies the platelet 5-HT/MAO system by inducing a demethylation of the MAO gene promoter resulting in high MAO protein concentration persisting more than ten years after quitting smoking. The present data enlarges the results to another MAO substrate, norepinephrine (NE), further confirming the central role of MAO in tobacco use-induced diseases. Thus, MAO could be a readily accessible and helpful marker in the risk evaluation of smoking-related diseases, from cardiovascular and pulmonary diseases to depression, anxiety and cancer. The present review implements the new finding of epigenetic regulation of MAO and suggests that smoking-induced MAO demethylation can be considered as a hallmark of smoking-related cancers similarly to other aberrant DNA methylations.

Plasma concentrations of soluble CD40 ligand in smokers with acute myocardial infarction: a pilot study

Coronary artery disease (CAD) is believed to be the single leading cause of death in both men and women in the world. Smoking is the most important risk factor for CAD. Smoking increases platelet aggregation and thrombus formation. CD40 ligand (CD40L) is a transmembrane glycoprotein derived from activated platelets. It participates in thrombus formation during the acute phase of acute myocardial infarction (MI). Elevation of CD40L identifies the patients who are at highest risk for cardiac events and who are likely to benefit from treatment with the glycoprotein IIb/IIIa (GPIIb/IIIa) receptor antagonists. The purpose of this study was to evaluate levels of CD40L in smokers with acute MI. Fifty-seven patients with acute MI were enrolled in this study. Thirty-one smokers were compared with 26 non-smokers. Soluble CD40L level in the plasma was determined by a standard enzyme-linked immunosorbent assay. Circulating levels of CD40L were higher in the smokers' group. Smokers with acute MI may have increased risk for thrombotic complications during acute MI, and optimal antiaggregant therapy should be administered.

Perioperative platelet and monocyte activation in patients with critical limb ischemia

BACKGROUND

Patients with critical limb ischemia (CLI) have a high rate of adverse cardiovascular events, particularly when undergoing surgery. We sought to determine the effect of surgery and vascular disease on platelet and monocyte activation in vivo in patients with CLI.

METHODS

An observational, cross-sectional study was performed at a tertiary referral hospital in the southeast of Scotland. Platelet and monocyte activation were measured in whole blood in patients with CLI scheduled for infrainguinal bypass and compared with matched healthy controls, patients with chronic intermittent claudication, patients with acute myocardial infarction, and those undergoing arthroplasty (n = 30 per group). Platelet and monocyte activation were quantified using flow cytometric assessment of platelet-monocyte aggregation, platelet P-selectin expression, platelet-derived microparticles, and monocyte CD40 and CD11b expression.

RESULTS

Compared with those with intermittent claudication, subjects with CLI had increased platelet-monocyte aggregates (41.7% +/- 12.2% vs 32.6% +/- 8.5%, respectively), platelet microparticles (178.7 +/- 106.9 vs 116.9 +/- 53.4), and monocyte CD40 expression (70.0% +/- 12.2% vs 52.4% +/- 15.2%; P < .001 for all). Indeed, these levels were equivalent (P-selectin, 4.4% +/- 2.0% vs 4.9% +/- 2.2%; P > .05) or higher (platelet-monocyte aggregation, 41.7% +/- 12.2% vs 33.6% +/- 7.0%; P < .05; platelet microparticles, 178.7 +/- 106.9 vs 114.4 +/- 55.0/microL; P < .05) than in patients with acute myocardial infarction. All platelet and monocyte activation markers remained elevated throughout the perioperative period in patients with CLI (P < .01) but not those undergoing arthroplasty.

CONCLUSIONS

Patients undergoing surgery for CLI have the highest level of in vivo platelet and monocyte activation, and these persist throughout the perioperative period. Additional antiplatelet therapy may be of benefit in protecting vascular patients with more severe disease during this period of increased risk.

Exposure to acrolein by inhalation causes platelet activation

Acrolein is a common air pollutant that is present in high concentrations in wood, cotton, and tobacco smoke, automobile exhaust and industrial waste and emissions. Exposure to acrolein containing environmental pollutants such as tobacco smoke and automobile exhaust has been linked to the activation of the coagulation and hemostasis pathways and thereby to the predisposition of thrombotic events in human. To examine the effects of acrolein on platelets, adult male C57Bl/6 mice were subjected acute (5ppm for 6h) or sub-chronic (1ppm, 6h/day for 4days) acrolein inhalation exposures. The acute exposure to acrolein did not cause pulmonary inflammation and oxidative stress, dyslipidemia or induce liver damage or muscle injury. Platelet GSH levels in acrolein-exposed mice were comparable to controls, but acrolein-exposure increased the abundance of protein-acrolein adducts in platelets. Platelets isolated from mice, exposed to both acute and sub-chronic acrolein levels, showed increased ADP-induced platelet aggregation. Exposure to acrolein also led to an increase in the indices of platelet activation such as the formation of platelet-leukocyte aggregates in the blood, plasma PF4 levels, and increased platelet-fibrinogen binding. The bleeding time was decreased in acrolein exposed mice. Plasma levels of PF4 were also increased in mice exposed to environmental tobacco smoke. Similar to inhalation exposure, acrolein feeding to mice also increased platelet activation and established a pro-thrombotic state in mice. Together, our data suggest that acrolein is an important contributing factor to the pro-thrombotic risk in human exposure to pollutants such as tobacco smoke or automobile exhaust, or through dietary consumption.

Smoking and atherosclerotic cardiovascular disease: part II: role of cigarette smoking in cardiovascular disease development

Potential mechanisms and biomarkers of atherosclerosis related to cigarette smoking - a modifiable risk factor for that disease - are discussed in this article. These include smoking-associated inflammatory markers, such as leukocytes, high-sensitivity C-reactive protein, serum amyloid A, ICAM-1 and IL-6. Other reviewed markers are indicative for smoking-related impairment of arterial endothelial function (transcapillary leakage of albumin, inhibition of endogenous nitric oxide synthase activity and reduced endothelium-dependent vasodilation) or point to oxidative stress caused by various chemicals (cholesterol oxidation, autoantibodies to oxidized low-density lipoprotein, plasma levels of malondialdehyde and F(2)-isoprostanes and reduced antioxidant capacity). Smoking enhances platelet aggregability, increases blood viscosity and shifts the pro- and antithrombotic balance towards increased coagulability (e.g., fibrinogen, von Willebrand factor, ICAM-1 and P-selectin). Insulin resistance is higher in smokers compared with nonsmokers, and hemoglobin A1c is dose-dependently elevated, as is homocysteine. Smoke exposure may influence the kinetics of markers with different response to transient or chronic changes in cigarette smoking behavior.

Pre-operative platelet-bound CD40 ligand is probably associated with peri-operative cardiac events in hip and knee arthroplasty

BACKGROUND

Peri-operative cardiac events are common and associated with significant morbidity. A predictive biomarker would assist in pre-operative risk stratification of surgical patients. This study explored the utility of pre-operative measurements of platelet-bound CD40 ligand and other biomarkers for predicting peri-operative cardiac events in total hip or knee arthroplasty.

METHODS

Blood samples were collected from 62 patients prior to surgery and tested for the biomarkers platelet CD40 ligand, platelet factor V/Va, platelet P-selectin, high-sensitivity C-reactive protein, B-type natriuretic peptide and soluble CD40 ligand. The Revised Cardiac Risk Index was also calculated. Patients were then followed up prospectively and screened for peri-operative cardiac events by means of ECG, serial troponin I, a cardiologist's review and an interview at 6 weeks post operation.

RESULTS

Six of 62 (9.7%) patients had a cardiac event. Patients who experienced a cardiac event had higher pre-operative platelet CD40 ligand levels as measured by flow cytometry [median 0.55% vs. 0.29% (P = 0.02)]. In this sized sample, platelet CD40L was the only biomarker independently associated with cardiac events (P = 0.02), the area under the receiver-operator characteristic curve being 0.79.

CONCLUSION

In a study of this number of patients, of the six biomarkers tested, only platelet CD40 ligand was found to have a probable association with peri-operative cardiac events in hip and knee arthroplasty.