Dyslipidemia shifts the tissue factor/tissue factor pathway inhibitor balance toward increased thrombogenicity in atherosclerotic plaques: evidence for a corrective effect of statins

Non-O Blood Group Is Associated with High Thrombus Burden and Poor Short- and Long-Term Prognosis in ST-Segment Elevation Myocardial Infarction Patients

INTRODUCTION

This study investigated how non-O blood groups relate to thrombus burden (TB) and prognosis in ST-segment elevation myocardial infarction (STEMI) patients, aiming to shed light on their association with thrombotic complications in cardiovascular diseases.

METHODS

Retrospectively, 1,180 STEMI patients undergoing primary percutaneous coronary intervention were included. The study population was divided into groups according to TB status and the groups were compared in terms of basic clinical characteristics, laboratory parameters and ABO blood group types. In addition, short-term (30 days) and long-term (12 months) clinical outcomes were assessed to evaluate the prognostic implications.

RESULTS

The analysis revealed a significant association between non-O blood groups and increased TB in STEMI patients (p = 0.001). Non-O blood group was independently associated with high TB (OR: 1.726, 95% confidence interval [CI]: 1.279-2.330, p < 0.001). Additionally, patients with non-O blood groups had higher short and long-term mortality rates (hazard ratio [HR]: 2.480, 95% CI: 1.361-4.520, p = 0.003; HR: 2.347, 95% CI: 1.433-3.844, p = 0.001; respectively).

CONCLUSIONS

This study emphasizes the significance of the ABO blood group system in STEMI outcomes, associating non-O blood groups with higher TB and poorer clinical outcomes. While proposing personalized treatment strategies based on blood group status to improve reperfusion interventions and outcomes, additional trials are needed to comprehensively evaluate their impact.

Inflammasome Activation: A Keystone of Proinflammatory Response in Obstructive Sleep Apnea

RATIONALE

As the mechanism that links obstructive sleep apnea (OSA) with the regulation of inflammatory response is not well known, it is important to understand the inflammasome activation, mainly of nucleotide-binding oligomerization domain-like receptor 3 (NLRP3).

OBJECTIVES

To assess the NLRP3 activity in severe OSA patients and to identify its role in the systemic inflammatory response of OSA patients.

METHODS

We analyzed the NLRP3 activity as well as key components of the inflammasome cascade, such as adaptor molecule apoptosis-associated speck-like protein (ASC), caspase-1, Gasdermin D (GSDMD), interleukin (IL)-1β, IL-18 and tissue factor (TF), in monocytes and plasma from patients with severe OSA and non-apneic healthy subjects. We explored the association of the different key markers with inflammatory comorbidities.

MAIN RESULTS

Monocytes from patients with severe OSA presented higher NLRP3 activity than those from non-apneic control subjects, which directly correlated with the apnea-hypopnea index and hypoxemic indices. NLRP3 over-activity triggered inflammatory cytokines (Il-1β and IL-18) via caspase-1 and increased Gasdermin D, allowing for tissue factor to be released. In vitro models confirmed that monocytes increase NLRP3 signaling under intermittent hypoxia (IH) in an HIF-1α-dependent manner, and/or in combination with plasma from OSA patients. Plasma levels of TF were higher in OSA patients with systemic inflammatory comorbidities than in those without them.

CONCLUSIONS

In severe OSA patients, NLRP3 activation might be a linking mechanism between intermittent hypoxia and other OSA-induced immediate changes with the development of systemic inflammatory response.

Association of circulating proprotein convertase subtilisin/kexin type 9 concentration, prothrombin time and cardiovascular outcomes: a prospective cohort study

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is considered to have multiple roles in the development of atherosclerosis, which is recently reported to participate in the thrombotic process. We aimed to examine the relationship between PCSK9 concentration, coagulation indexes and cardiovascular events.

METHODS

A total of 2293 consecutive patients with angina-like chest pain and without lipid-lowering drugs treatment were enrolled and followed up for major adverse cardiovascular events (MACEs). Circulating PCSK9 concentration was determined by ELISA. The routine coagulation tests including activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time were performed. The associations between PCSK9 concentration, routine coagulation indicators and MACEs were analyzed.

RESULTS

Patients with high PCSK9 levels had lower PT and APTT levels (all p <  0.05). However, PCSK9 concentration was only independently and negatively correlated with PT (β = - 0.115, p <  0.001). During a mean of 38.3 months, 186 (8.1%) MACEs were occurred. Multiple Cox regression analysis indicated high PCSK9 or low PT levels as risk factors related to MACEs. When the prognosis was analyzed by the combination of PCSK9 and PT levels, patients with high PCSK9 and low PT had higher incidence of MACEs compared to those with low PCSK9 and high PT.

CONCLUSIONS

Our study firstly suggested that PCSK9 concentration was negatively correlated with plasma levels of PT. Furthermore, high PCSK9 and low PT were associated with MACEs and the combination of PCSK9 with PT had an addictive effect on predicting cardiovascular outcomes in patients with chest pain, which was useful for further subdivision of cardiovascular risks.

Relation between Tissue Factor Pathway Inhibitor Activity and Cardiovascular Risk Factors and Diseases in a Large Population Sample

OBJECTIVE

 Tissue factor pathway inhibitor (TFPI) is a potent anticoagulant protein in the extrinsic coagulation pathway. In the present study, we aim to identify the cardiovascular determinants for total TFPI activity and its association with cardiovascular disease (CVD) and total mortality.

METHODS

 Total TFPI activity was assessed in a selection of the population-based Gutenberg Health Study (n = 5,000). Statistical analysis was performed to identify the determinants for total TFPI activity as well as the associations with CVD and mortality.

RESULTS

 Multivariable linear regression analysis identified smoking (β 0.095 [0.054-0.136]) as a positive determinant for total TFPI activity, while diabetes (β -0.072 [-0.134 to -0.009]), obesity (β -0.063 [-0.101 to -0.024]), and history of coronary artery disease (CAD) were negatively associated with total TFPI activity, independent of age, sex, and the remaining cardiovascular risk factors. After adjustment for lipoprotein levels, the association between total TFPI activity levels and obesity and CAD was lost. The analysis additionally revealed a strong positive association between total TFPI activity levels and low-density lipoprotein (β 0.221 [0.204-0.237]). The Cox regression models revealed that a higher total TFPI activity, above 97.5th percentile of the reference group, was associated with an increased mortality risk (hazard ratio = 2.58 [95% confidence interval: 1.49-4.47]), independent of age, sex, and cardiovascular risk profile.

CONCLUSION

 In the Gutenberg Health Study population-based cohort, the highest percentage of total TFPI correlated with an increased mortality risk. While elevated TFPI may reflect endothelial cell activation, the associations between total TFPI activity and obesity and CAD, points to additional mechanistic interactions.

Relationship between dyslipidemia and carotid plaques in a high-stroke-risk population in Shandong Province, China

INTRODUCTION

The precise associations between stroke and carotid plaques and dyslipidemia are unclear. This population-based study aimed to examine the relationship between carotid plaques and dyslipidemia in a high-stroke-risk population.

METHODS

Ultrasonography of left and right carotid arteries was conducted in 22,222 participants in a second screening survey of individuals with high stroke risk. Subjects were divided into two groups according to the presence or absence of carotid plaques. Blood TC (total cholesterol), TG (total triglycerides), and LDL-C (low-density lipoprotein cholesterol) levels were recorded.

RESULTS

Multivariate logistic regression analysis, controlled for gender, age, education, geographic region, smoking, exercise, and overweight (Model 2), identified TG as a predictor of carotid-plaque risk (odds ratio [OR] = 1.109, 95% confidence interval [CI]: 1.038-1.185, P = 0.002), and the association between carotid plaques and LDL-C (OR = 0.967, 95%CI: 0.949-0.994, P = 0.019) was less significant, whereas there was no association between carotid plaques and TC (OR = 1.002, 95%CI: 0.932-1.007, P = 0.958). After additional adjustment for hypertension, diabetes, and atrial fibrillation (Model 3), TG remained a risk factor for carotid plaques (OR = 1.086, 95%CI: 1.016-1.161, P = 0.015), but no associations were observed between carotid plaques and LDL-C (OR = 0.972, 95%CI: 0.910-1.038, P = 0.394) or TC (OR = 1.003, 95%CI: 0.933-1.079, P = 0.928). Only the association between TG and carotid plaques (OR = 1.084, 95%CI: 1.014-1.159, P = 0.017) was independent of all covariates (covariates in Model 3 plus history of stroke or transient ischemic attack, and stroke family history) in Model 4.

CONCLUSION

These findings indicate that TG was an independent risk factor for carotid plaques in high-risk population for stroke, whereas LDL-C and TC were not associated with the appearance of carotid plaques independently.

M1 and M2 macrophage proteolytic and angiogenic profile analysis in atherosclerotic patients reveals a distinctive profile in type 2 diabetes

This study aimed to investigate atherosclerotic mediators' expression levels in M1 and M2 macrophages and to focus on the influence of diabetes on M1/M2 profiles. Macrophages from 36 atherosclerotic patients (19 diabetics and 17 non-diabetics) were cultured with interleukin-1β (IL-1β) or IL-4 to induce M1 or M2 phenotype, respectively. The atherosclerotic mediators' expression was evaluated by quantitative reverse transcription-polymerase chain reaction (RT-PCR). The results showed that M1 and M2 macrophages differentially expressed mediators involved in proteolysis and angiogenesis processes. The proteolytic balance (matrix metalloproteinase-9 (MMP-9)/tissue inhibitor of metalloproteinase-1 (TIMP-1), MMP-9/plasminogen activator inhibitor-1 (PAI-1) and MMP-9/tissue factor pathway inhibitor-2 (TFPI-2) ratios) was higher in M1 versus M2, whereas M2 macrophages presented higher angiogenesis properties (increased vascular endothelial growth factor/TFPI-2 and tissue factor/TFPI-2 ratios). Moreover, M1 macrophages from diabetics displayed more important proangiogenic and proteolytic activities than non-diabetics. This study reveals that M1 and M2 macrophages could differentially modulate major atherosclerosis-related pathological processes. Moreover, M1 macrophages from diabetics display a deleterious phenotype that could explain the higher plaque vulnerability observed in these subjects.

Vascular wall hypoxia promotes arterial thrombus formation via augmentation of vascular thrombogenicity

Atherosclerotic lesions represent a hypoxic milieu. However, the significance of this milieu in atherothrombosis has not been established. We aimed to assess the hypothesis that vascular wall hypoxia promotes arterial thrombus formation. We examined the relation between vascular wall hypoxia and arterial thrombus formation using a rabbit model in which arterial thrombosis was induced by 0.5 %-cholesterol diet and repeated balloon injury of femoral arteries. Vascular wall hypoxia was immunohistochemically detected by pimonidazole hydrochloride, a hypoxia marker. Rabbit neointima and THP-1 macrophages were cultured to analyse prothrombotic factor expression under hypoxic conditions (1 % O2). Prothrombotic factor expression and nuclear localisation of hypoxia-inducible factor (HIF)-1α and nuclear factor-kappa B (NF-κB) p65 were immunohistochemically assessed using human coronary atherectomy plaques. Hypoxic areas were localised in the macrophage-rich deep portion of rabbit neointima and positively correlated with the number of nuclei immunopositive for HIF-1α and NF-κB p65, and tissue factor (TF) expression. Immunopositive areas for glycoprotein IIb/IIIa and fibrin in thrombi were significantly correlated with hypoxic areas in arteries. TF and plasminogen activator inhibitor-1 (PAI-1) expression was increased in neointimal tissues and/or macrophages cultured under hypoxia, and both were suppressed by inhibitors of either HIF-1 or NF-κB. In human coronary plaques, the number of HIF-1α-immunopositive nuclei was positively correlated with that of NF-κB-immunopositive nuclei and TF-immunopositive and PAI-1-immunopositive area, and it was significantly higher in thrombotic plaques. Vascular wall hypoxia augments the thrombogenic potential of atherosclerotic plaque and thrombus formation on plaques via prothrombotic factor upregulation.

The coronary artery disease-associated gene C6ORF105 is expressed in human macrophages under the transcriptional control of PPARγ

Coronary artery disease (CAD) is a major cause of morbidity and mortality. Mutations in C6ORF105, associated with decreased gene expression, positively correlate with the risk of CAD in Chinese populations. Moreover, the C6ORF105-encoded protein may play a role in coagulation. Here, we report that C6ORF105 gene expression is lower in circulating mononuclear cells from obese diabetic than lean subjects. Moreover, C6ORF105 is expressed in human macrophages and atherosclerotic lesions, where its expression positively correlates with expression of the transcription factor Peroxisome Proliferator-Activated Receptor (PPAR)γ. Activation of PPARγ increases, in a PPARγ-dependent manner, the expression of C6ORF105 in human macrophages and atherosclerotic lesions.

The role of tissue factor pathway inhibitor in atherosclerosis and arterial thrombosis

Tissue factor pathway inhibitor (TFPI) is the main inhibitor of tissue factor (TF)-mediated coagulation. In atherosclerotic plaques TFPI co-localizes with TF, where it is believed to play an important role in attenuating TF activity. Findings in animal models such as TFPI knockout models and gene transfer models are consistent on the role of TFPI in arterial thrombosis as they reveal an active role for TFPI in attenuating arterial thrombus formation. In addition, ample experimental evidence exists indicating that TFPI has inhibitory effects on both smooth muscle cell migration and proliferation, both which are recognized as important pathological features in atherosclerosis development. Nonetheless, the clinical relevance of these antithrombotic and atheroprotective effects remains unclear. Paradoxically, the majority of clinical studies find increased instead of decreased TFPI antigen and activity levels in atherothrombotic disease, particularly in atherosclerosis and coronary artery disease (CAD). Increased TFPI levels in cardiovascular disease might result from complex interactions with established cardiovascular risk factors, such as hypercholesterolemia, diabetes and smoking. Moreover, it is postulated that increased TFPI levels reflect either the amount of endothelial perturbation and platelet activation, or a compensatory mechanism for the increased procoagulant state observed in cardiovascular disease. In all, the prognostic value of plasma TFPI in cardiovascular disease remains to be established. The current review focuses on TFPI in clinical studies of asymptomatic and symptomatic atherosclerosis, coronary artery disease and ischemic stroke, and discusses potential atheroprotective actions of TFPI.

Circulating monocytes mirror the imbalance in TF and TFPI expression in carotid atherosclerotic plaques with lipid-rich and calcified morphology

BACKGROUND

Thrombogenicity of atherosclerotic plaque largely depends on plaque morphology and their content of tissue factor (TF) and tissue factor pathway inhibitor (TFPI). The relationship between morphological composition of plaque (lipid-rich or calcified) and expression of TF and TFPI in circulating blood monocytes and within the plaques is not characterized.

OBJECTIVE

To investigate whether lipid-rich (echolucent) or calcified (echogenic) morphology of carotid atherosclerotic plaques is associated with differences in TF and TFPI expression in circulating blood monocytes and within carotid atherosclerotic plaques.

METHODS

We studied levels of monocyte TF and TFPI mRNA and protein expression and association with traditional risk factors for atherosclerosis in asymptomatic subjects with echolucent (n=20) or echogenic (n=20) carotid plaques, or controls without carotid atherosclerosis (n=20) determined by ultrasonography. Sections of calcified or lipid-rich carotid plaques obtained from symptomatic patients were assessed for TF and TFPI antigen expression.

RESULTS

TF and TFPI surface presentation, surface TF/TFPI ratio, and TF activity were higher in monocytes obtained from subjects with echolucent than with echogenic plaques or controls without carotid atherosclerosis. Multiple regression analyses revealed inverse association between serum apoA1 and monocyte surface TF antigen expression (p=0.007), and positive association between serum apoB and monocyte surface TFPI expression (p=0.028). Sections from lipid-rich carotid plaques contained 2.5-fold more TF and 1.5-fold more TFPI antigens relative to calcified lesions, also yielding a higher TF/TFPI ratio.

CONCLUSIONS

Our findings indicate that circulating monocytes of asymptomatic individuals with echolucent lipid-rich carotid atherosclerosis express an imbalance between TF and TFPI expression cohering with changes found within advanced carotid atherosclerotic plaques obtained from symptomatic patients.

Tissue Factor, Tissue Factor Pathway Inhibitor and Factor VII Activity in Cardiovascular Complicated Type 2 Diabetes Mellitus

OBJECTIVES

Tissue factor (TF) is the main initiator of the extrinsic coagulation pathway through factor VII (FVII) activation, which is physiologically inhibited by tissue factor pathway inhibitor (TFPI). Alteration of this pathway has been described in Type 2 diabetes mellitus (T2DM). The aim of this study is to assess TF and TFPI plasma levels and FVII coagulant activity (FVIIa) in T2DM in relation to cardiothrombotic disease and their correlation to metabolic and clinical behavior of the patients.

METHODS

The study was conducted on 80 T2DM patients divided to accordingly; groupI: 40 patients without a history or clinically detected heart disease, and groupII: 40 patients with a history of myocardial infarction compared to 30 controls. The patients were recruited from Ain Shams University diabetes clinic from September 2007 to February 2009 after informed consent was obtained. Peripheral blood samples were taken for measurement of plasma TF and TFPI levels using ELISA technique and quantitative FVIIa using FVII deficient plasma.

RESULTS

Plasma levels of TF, TFPI and FVIIa were significantly higher in T2DM patients compared to the controls (p<0.001). TF (236.50±79.23)and TFPI (242.33±85.84)were significantly higher in group II, compared to group I (150.33±81.16), (152.8± 82.46), (p<0.001). TF and TFPI were significantly correlated to body mass index and glycemic control. Also, TF and TFPI were significantly higher in hypertensives (p=0.001) and dyslipidemics (p=0.006) but not in smokers (p=0.64), (p=0.11) respectively.

CONCLUSION

There was a correlation between high TF, TFPI plasma levels, FVIIa activity and cardiothrombotic complications in T2DM especially in the presence of high risk factors such as poor glycemic control, dyslipidemia and obesity. Future target therapy against TF may be beneficial for T2DM patients.

Human atherosclerotic plaque alternative macrophages display low cholesterol handling but high phagocytosis because of distinct activities of the PPARγ and LXRα pathways

RATIONALE

A crucial step in atherogenesis is the infiltration of the subendothelial space of large arteries by monocytes where they differentiate into macrophages and transform into lipid-loaded foam cells. Macrophages are heterogeneous cells that adapt their response to environmental cytokines. Th1 cytokines promote monocyte differentiation into M1 macrophages, whereas Th2 cytokines trigger an "alternative" M2 phenotype.

OBJECTIVE

We previously reported the presence of CD68(+) mannose receptor (MR)(+) M2 macrophages in human atherosclerotic plaques. However, the function of these plaque CD68(+)MR(+) macrophages is still unknown.

METHODS AND RESULTS

Histological analysis revealed that CD68(+)MR(+) macrophages locate far from the lipid core of the plaque and contain smaller lipid droplets compared to CD68(+)MR(-) macrophages. Interleukin (IL)-4-polarized CD68(+)MR(+) macrophages display a reduced capacity to handle and efflux cellular cholesterol because of low expression levels of the nuclear receptor liver x receptor (LXR)α and its target genes, ABCA1 and apolipoprotein E, attributable to the high 15-lipoxygenase activity in CD68(+)MR(+) macrophages. By contrast, CD68(+)MR(+) macrophages highly express opsonins and receptors involved in phagocytosis, resulting in high phagocytic activity. In M2 macrophages, peroxisome proliferator-activated receptor (PPAR)γ activation enhances the phagocytic but not the cholesterol trafficking pathways.

CONCLUSIONS

These data identify a distinct macrophage subpopulation with a low susceptibility to become foam cells but high phagocytic activity resulting from different regulatory activities of the PPARγ-LXRα pathways.

Postoperative Statin Therapy Attenuates the Intensity of Systemic Inflammation and Increases Fibrinolysis After Coronary Artery Bypass Grafting

A total of 25 patients undergoing coronary artery bypass grafting (CABG) were included in the study. Patients received statin (20 mg daily) postoperatively for 2 weeks. All analyses were performed at 2 different time points: preoperatively (group 1) and 2 weeks after operation (group 2). Interleukin (IL)-6, IL-8, plasminogen activator inhibitor 1 (PAI-1), tumor necrosis factor α (TNF-α), tissue plasminogen activator (t-PA) levels, and tissue factor pathway inhibitor (TFPI) were evaluated. Statin treatment caused a significant reduction in the plasma level of PAI-1 (preop: 15.04 ± 0.13 ng/mL vs postop: 13.89 ± 2.14 ng/mL; P < .05) and increased t-PA levels (preop: 109.74 ± 0.13 vs postop: 231.40 ± 1.22 ng/mL; P < .001). Plasma TNF-α and IL-6 levels did not change with treatment. Statin treatment caused a significant reduction in plasma IL-8 level (279.70 ± 3.42 ng/mL vs postop: 207.18 ± 3.63 ng/mL, P < .05), and TFPI (4.87 ± 2.05 ng/mL vs postop: 6.27 ± 1.25 ng/mL; P < .05). The results demonstrate that atorvastatin attenuates systemic inflammatory reaction after cardiac surgery.

Unlike PPARgamma, PPARalpha or PPARbeta/delta activation does not promote human monocyte differentiation toward alternative macrophages

Macrophages adapt their response to micro-environmental signals. While Th1 cytokines promote pro-inflammatory M1 macrophages, Th2 cytokines promote an "alternative" anti-inflammatory M2 macrophage phenotype. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors expressed in macrophages where they control the inflammatory response. It has been shown that PPARgamma promotes the differentiation of monocytes into anti-inflammatory M2 macrophages in humans and mice, while a role for PPARbeta/delta in this process has been reported only in mice and no data are available for PPARalpha. Here, we show that in contrast to PPARgamma, expression of PPARalpha and PPARbeta/delta overall does not correlate with the expression of M2 markers in human atherosclerotic lesions, whereas a positive correlation with genes of lipid metabolism exists. Moreover, unlike PPARgamma, PPARalpha or PPARbeta/delta activation does not influence human monocyte differentiation into M2 macrophages in vitro. Thus, PPARalpha and PPARbeta/delta do not appear to modulate the alternative differentiation of human macrophages.

Tissue factor pathway inhibitor-2 gene methylation is associated with low expression in carotid atherosclerotic plaques

BACKGROUND

The tissue factor pathway inhibitor-2 (TFPI-2) is a Kunitz-type serine-protease inhibitor which is expressed in atherosclerotic plaques. Epigenetic regulation of the TFPI-2 gene, through methylation of CpG islands, has been advocated in cancer. We hypothesized that TFPI-2 gene methylation could regulate TFPI-2 expression in atherosclerosis.

METHODS

We used Methylation Specific PCR (MSP) and pyrosequencing in order to identify 18 CpG of the TFPI-2 promoter, in 59 carotid atherosclerotic plaques and 26 control mammary arteries.

RESULTS

MSP showed methylation of the TFPI-2 gene (MSP+) in 16 plaques (27%), while no methylation (MSP-) was found in control arteries. Pyrosequencing confirmed that MSP+ plaques presented higher methylation levels than MSP- ones and arteries (p=0.03 and 0.01). Moreover, the TFPI-2 mRNA levels were lower in methylated plaques than in unmethylated ones and than in arteries (p=0.04 and <0.0001). The methylated plaques contained less lipids and macrophage infiltration than unmethylated ones. Their TFPI-2 immunoreactivity was mainly detected in the macrophages located in the media on the adventitial side, rather than in the lipid-rich core.

CONCLUSION

Methylation of the TFPI-2 gene takes place in atherosclerotic plaques and is associated with decreased TFPI-2 expression. The place of this process in atherosclerosis progression remains to be investigated.