High-density lipoprotein enhancement of anticoagulant activities of plasma protein S and activated protein C

Metabolic landscape in venous thrombosis: insights into molecular biology and therapeutic implications

The findings of the last decade suggest a complex link between inflammatory cells, coagulation, and the activation of platelets and their synergistic interaction to promote venous thrombosis. Inflammation is present throughout the process of venous thrombosis, and various metabolic pathways of erythrocytes, endothelial cells, and immune cells involved in venous thrombosis, including glucose metabolism, lipid metabolism, homocysteine metabolism, and oxidative stress, are associated with inflammation. While the metabolic microenvironment has been identified as a marker of malignancy, recent studies have revealed that for cancer thrombosis, alterations in the metabolic microenvironment appear to also be a potential risk. In this review, we discuss how the synergy between metabolism and thrombosis drives thrombotic disease. We also explore the great potential of anti-inflammatory strategies targeting venous thrombosis and the complex link between anti-inflammation and metabolism. Furthermore, we suggest how we can use our existing knowledge to reduce the risk of venous thrombosis.

Clot or Not? Reviewing the Reciprocal Regulation Between Lipids and Blood Clotting

Both hyperlipidemia and thrombosis contribute to the risks of atherosclerotic cardiovascular diseases, which are the leading cause of death and reduced quality of life in survivors worldwide. The accumulation of lipid-rich plaques on arterial walls eventually leads to the rupture or erosion of vulnerable lesions, triggering excessive blood clotting and leading to adverse thrombotic events. Lipoproteins are highly dynamic particles that circulate in blood, carry insoluble lipids, and are associated with proteins, many of which are involved in blood clotting. A growing body of evidence suggests a reciprocal regulatory relationship between blood clotting and lipid metabolism. In this review article, we summarize the observations that lipoproteins and lipids impact the hemostatic system, and the clotting-related proteins influence lipid metabolism. We also highlight the gaps that need to be filled in this area of research.

Dyslipidaemia-Genotype Interactions with Nutrient Intake and Cerebro-Cardiovascular Disease

A comprehensive understanding of gene-diet interactions is necessary to establish proper dietary guidelines to prevent and manage cardio-cerebrovascular disease (CCD). We investigated the role of genetic variants associated with dyslipidaemia (DL) and their interactions with macro-nutrients for cardiovascular disease using a large-scale genome-wide association study of Korean adults. A total of 58,701 participants from a Korean genome and epidemiology study were included. Their dietary intake was assessed using a food frequency questionnaire. Dyslipidaemia was defined as total cholesterol (TCHL) ≥ 240 mg/dL, high-density lipoprotein (HDL) < 40 mg/dL, low-density lipoprotein (LDL) ≥ 160 mg/dL, triglycerides (TG) ≥ 200 mg/dL, or dyslipidaemia history. Their nutrient intake was classified as follows: protein intake: high ≥ 30%, 30% > moderate ≥ 20%, and 20% > low in daily total energy intake (TEI); carbohydrate intake: high ≥ 60%, 60% > moderate ≥ 50%, and 50% > low; fat intake: high ≥ 40%, 40% > moderate ≥ 30%, and 30% > low. Odds ratios and 95% confidence intervals were calculated after adjusting for age; sex; body mass index (BMI); exercise status; smoking status; alcohol intake; principal component 1 (PC1); principal component 2 (PC2); and intake of carbohydrates, fats, and proteins. This analysis included 20,596 patients with dyslipidaemia and 1027 CCD patients. We found that rs2070895 related to LIPC was associated with HDL-cholesterol. Patients with the minor allele (A) in rs2070895 had a lower risk of CCD than those carrying the reference allele (G) (odds ratio [OR] = 0.8956, p-value = 1.78 × 10−2). Furthermore, individuals consuming protein below 20% TEI with the LIPC reference allele had a higher risk of CCD than those with the minor allele (interaction p-value 6.12 × 10−3). Our findings suggest that the interactions of specific polymorphisms associated with dyslipidaemia and nutrients intake can influence CCD.

Predicting psoriasis using routine laboratory tests with random forest

Psoriasis is a chronic inflammatory skin disease that affects approximately 125 million people worldwide. It has significant impacts on both physical and emotional health-related quality of life comparable to other major illnesses. Accurately prediction of psoriasis using biomarkers from routine laboratory tests has important practical values. Our goal is to derive a powerful predictive model for psoriasis disease based on only routine hospital tests. We collected a data set including 466 psoriasis patients and 520 healthy controls with 81 variables from only laboratory routine tests, such as age, total cholesterol, HDL cholesterol, blood pressure, albumin, and platelet distribution width. In this study, Boruta feature selection method was applied to select the most relevant features, with which a Random Forest model was constructed. The model was tested with 30 repetitions of 10-fold cross-validation. Our classification model yielded an average accuracy of 86.9%. 26 notable features were selected by Boruta, among which 15 features are confirmed from previous studies, and the rest are worth further investigations. The experimental results demonstrate that the machine learning approach has good potential in predictive modeling for the psoriasis disease given the information only from routine hospital tests.

Combination of D-dimer level and neutrophil to lymphocyte ratio predicts long-term clinical outcomes in acute coronary syndrome after percutaneous coronary intervention

BACKGROUND

High D-dimer (DD) is associated with short-term adverse outcomes in patients with acute coronary syndrome (ACS). In ACS patients who underwent percutaneous coronary intervention (PCI), however, the value of DD (or combined with neutrophil to lymphocyte ratio [NLR]) to predict long-term major adverse cardiovascular events (MACEs) has not been fully evaluated.

METHODS

Patients diagnosed with ACS and receiving PCI were included. The primary outcome was MACEs. Cox proportional hazards regression and logistic regression were used to illustrate the relationship between clinical risk factors, biomarkers and MACEs. Survival models were developed based on significant factors and evaluated by the Concordance-index (C-index).

RESULTS

The final study cohort was comprised of 650 patients (median age, 64 years; 474 males), including 98 (15%) with MACEs during a median follow-up period of 40 months. According to the cut-off value of DD and NLR, the patients were separated into four groups: high DD or nonhigh DD with high or nonhigh NLR. After adjusting for confounding variables, DD (adjusted hazard ratio [aHR]: 2.39, 95% confidence interval [CI]: 1.52-3.76) and NLR (aHR: 2.71, 95% CI: 1.78-4.11) were independently associated with long-term MACEs. Moreover, patients with both high DD and NLR had a significantly higher risk in MACEs when considering patients with nonhigh DD and NLR as reference (aHR: 6.19, 95% CI: 3.30-11.61). The area under curve increased and reached 0.70 in differentiating long-term MACEs when DD and NLR were combined, and survival models incorporating the two exhibited a stronger predictive power (C-index: 0.75).

CONCLUSIONS

D-dimer (or combined with NLR) can be used to predict long-term MACEs in ACS patients undergoing PCI.

Association of lipid profile with decompensation, liver dysfunction, and mortality in patients with liver cirrhosis

BACKGROUND AND AIMS

Lipid metabolism is often disrupted in liver cirrhosis. The present study aimed to evaluate the impact of lipid profile on decompensation events, severity of liver dysfunction, and death in patients with liver cirrhosis.

METHODS

In a cross-sectional study, 778 patients with lipid profile data were enrolled, and then were divided into 240 and 538 patients with and without liver cirrhosis, respectively. In a cohort study, 314 cirrhotic patients with lipid profile data, who were prospectively followed, were enrolled. Lipid profile included total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-c), low-density lipoprotein-cholesterol (LDL-c), triglycerides (TG), and lipoprotein(a).

RESULTS

In the cross-sectional study, cirrhotic patients with decompensation events had significantly lower levels of TC and lipoprotein(a) than those without; and cirrhotic patients with Child-Pugh class B and C had significantly lower levels of TC, HDL-c, LDL-c, and lipoprotein(a) than those with Child-Pugh class A. In the cohort study, there was an inverse association of survival with TC, HDL-c, and lipoprotein(a) levels; after adjusting for MELD score, TC (Hazard Ratio [HR] = 1.703, P = 0.034) and HDL-c (HR = 2.036, P = 0.005), but not lipoprotein(a) (HR = 1.377, P = 0.191), remained a significant predictor of death; when TC, HDL-c, lipoprotein(a), and MELD score were included in the multivariate Cox regression analysis, HDL-c (HR = 1.844, P = 0.024) was the only independent predictor of death.

CONCLUSIONS

Decreased levels in specific components of lipid profile indicate more decompensation events, worse liver function, and reduced survival in liver cirrhosis. MELD score combined with HDL-c should be promising for the assessment of outcomes of cirrhotic patients.

Dapagliflozin reduces thrombin generation and platelet activation: implications for cardiovascular risk reduction in type 2 diabetes mellitus

AIMS/HYPOTHESIS

People with diabetes have an increased cardiovascular risk with an accelerated development of atherosclerosis and an elevated mortality rate after myocardial infarction. Therefore, cardioprotective effects of glucose-lowering therapies are of major importance for the pharmacotherapy of individuals with type 2 diabetes. For sodium-glucose cotransporter 2 inhibitors (SGLT2is), in addition to a reduction in blood glucose, beneficial effects on atherosclerosis, obesity, renal function and blood pressure have been observed. Recent results showed a reduced risk of worsening heart failure and cardiovascular deaths under dapagliflozin treatment irrespective of the diabetic state. However, the underlying mechanisms are yet unknown. Platelets are known drivers of atherosclerosis and atherothrombosis and disturbed platelet activation has also been suggested to occur in type 2 diabetes. Therefore, the present study investigates the impact of the SGLT2i dapagliflozin on the interplay between platelets and inflammation in atherogenesis.

METHODS

Male, 8-week-old LDL-receptor-deficient (Ldlr-/-) mice received a high-fat, high-sucrose diabetogenic diet supplemented without (control) or with dapagliflozin (5 mg/kg body weight per day) for two time periods: 8 and 25 weeks. In a first translational approach, eight healthy volunteers received 10 mg dapagliflozin/day for 4 weeks.

RESULTS

Dapagliflozin treatment ameliorated atherosclerotic lesion development, reduced circulating platelet-leucocyte aggregates (glycoprotein [GP]Ib+CD45+: 29.40 ± 5.94 vs 17.00 ± 5.69 cells, p < 0.01; GPIb+lymphocyte antigen 6 complex, locus G+ (Ly6G): 8.00 ± 2.45 vs 4.33 ± 1.75 cells, p < 0.05) and decreased aortic macrophage infiltration (1.31 ± 0.62 vs 0.70 ± 0.58 ×103 cells/aorta, p < 0.01). Deeper analysis revealed that dapagliflozin decreased activated CD62P-positive platelets in Ldlr-/- mice fed a diabetogenic diet (3.78 ± 1.20% vs 2.83 ± 1.06%, p < 0.01) without affecting bleeding time (85.29 ± 37.27 vs 89.25 ± 16.26 s, p = 0.78). While blood glucose was only moderately affected, dapagliflozin further reduced endogenous thrombin generation (581.4 ± 194.6 nmol/l × min) × 10-9 thrombin vs 254.1 ± 106.4 (nmol/l × min) × 10-9 thrombin), thereby decreasing one of the most important platelet activators. We observed a direct inhibitory effect of dapagliflozin on isolated platelets. In addition, dapagliflozin increased HDL-cholesterol levels. Importantly, higher HDL-cholesterol levels (1.70 ± 0.58 vs 3.15 ± 1.67 mmol/l, p < 0.01) likely contribute to dapagliflozin-mediated inhibition of platelet activation and thrombin generation. Accordingly, in line with the results in mice, treatment with dapagliflozin lowered CD62P-positive platelet counts in humans after stimulation by collagen-related peptide (CRP; 88.13 ± 5.37% of platelets vs 77.59 ± 10.70%, p < 0.05) or thrombin receptor activator peptide-6 (TRAP-6; 44.23 ± 15.54% vs 28.96 ± 11.41%, p < 0.01) without affecting haemostasis.

CONCLUSIONS/INTERPRETATION

We demonstrate that dapagliflozin-mediated atheroprotection in mice is driven by elevated HDL-cholesterol and ameliorated thrombin-platelet-mediated inflammation without interfering with haemostasis. This glucose-independent mechanism likely contributes to dapagliflozin's beneficial cardiovascular risk profile.

The Role of High-Density Lipoprotein in COVID-19

The current Coronavirus disease 2019 (COVID-19) pandemic has become a global challenge. Managing a large number of acutely ill patients in a short time, whilst reducing the fatality rate and dealing with complications, brings unique difficulties. The most striking pathophysiological features of patients with severe COVID-19 are dysregulated immune responses and abnormal coagulation function, which can result in multiple-organ failure and death. Normally metabolized high-density lipoprotein (HDL) performs several functions, including reverse cholesterol transport, direct binding to lipopolysaccharide (LPS) to neutralize LPS activity, regulation of inflammatory response, anti-thrombotic effects, antioxidant, and anti-apoptotic properties. Clinical data shows that significantly decreased HDL levels in patients with COVID-19 are correlated with both disease severity and mortality. However, the role of HDL in COVID-19 and its specific mechanism remain unclear. In this analysis, we review current evidence mainly in the following areas: firstly, the pathophysiological characteristics of COVID-19, secondly, the pleiotropic properties of HDL, thirdly, the changes and clinical significance of HDL in COVID-19, and fourthly the prospect of HDL-targeting therapy in COVID-19 to clarify the role of HDL in the pathogenesis of COVID-19 and discuss the potential of HDL therapy in COVID-19.

High-Density Lipoprotein Cholesterol in Young Nondiabetic Coronary Heart Disease Patients

OBJECTIVE

To investigate the association between the lipid profiles and coronary heart disease (CHD) in nondiabetic patients younger than 65 years of age.

METHOD

424 patients were enrolled in this study from January 2019 to December 2020. All the patients were screened for clinically indicated coronary angiography. They were divided into two groups according to the coronary angiography results: 340 patients with the presence of CHD (at least one coronary artery stenosis ≥50%) were classified as the CHD group, and the rest with the absence of CHD comprised the normal group. The demographic data and lipid profiles were compared.

RESULT

CHD was higher in males than females (84.5% vs. 62.2%, P < 0.001). In the CHD group, the level of high-density lipoprotein cholesterol (HDL-C) was lower (P < 0.001), while the triglyceride (TG)/HDL-C ratio was higher (P=0.022). No significant differences were shown between the two groups in terms of age, family history of CHD, hypertension, and the levels of TC, TG, and LDL-C. Gender differences were further explored. In men, except for the level of HDL-C which was significantly lower in the CHD group than that in the normal group (P=0.017), parameters were comparable. A binary logistic regression model further indicated that HDL-C was associated with CHD (OR = 0.137, 95%CI: 0.031-0.594, P=0.008). Also, with the increase of the number of coronary artery with lesions, the levels of HDL-C decreased significantly in men. In women, no differences were observed between the CHD group and normal group.

CONCLUSION

HDL-C may be inversely associated with the risk of CHD in young nondiabetes patients, especially in men. More research is needed to confirm it.

Multifaced Roles of HDL in Sepsis and SARS-CoV-2 Infection: Renal Implications

High-density lipoproteins (HDLs) are a class of blood particles, principally involved in mediating reverse cholesterol transport from peripheral tissue to liver. Omics approaches have identified crucial mediators in the HDL proteomic and lipidomic profile, which are involved in distinct pleiotropic functions. Besides their role as cholesterol transporter, HDLs display anti-inflammatory, anti-apoptotic, anti-thrombotic, and anti-infection properties. Experimental and clinical studies have unveiled significant changes in both HDL serum amount and composition that lead to dysregulated host immune response and endothelial dysfunction in the course of sepsis. Most SARS-Coronavirus-2-infected patients admitted to the intensive care unit showed common features of sepsis disease, such as the overwhelmed systemic inflammatory response and the alterations in serum lipid profile. Despite relevant advances, episodes of mild to moderate acute kidney injury (AKI), occurring during systemic inflammatory diseases, are associated with long-term complications, and high risk of mortality. The multi-faceted relationship of kidney dysfunction with dyslipidemia and inflammation encourages to deepen the clarification of the mechanisms connecting these elements. This review analyzes the multifaced roles of HDL in inflammatory diseases, the renal involvement in lipid metabolism, and the novel potential HDL-based therapies.

Apolipoprotein A-I enhances activated protein C cytoprotective activity

High-density lipoprotein and apolipoprotein A-I enhance activated protein C cytoprotective activity. High-density lipoprotein and apolipoprotein A-I significantly increase the rate at which activated protein C degrades cytotoxic extracellular histones.

Skeletal muscle myosin and cardiac myosin attenuate heparin's antithrombin-dependent anticoagulant activity

BACKGROUND

Heparin enhances the ability of the plasma protease inhibitor, antithrombin, to neutralize coagulation factor Xa and thrombin. Skeletal muscle myosin binds unfractionated heparin.

OBJECTIVES

The aim of this study was to investigate the influence of myosin binding to heparin on antithrombin's anticoagulant activity.

METHODS

Inhibition of factor Xa and thrombin by antithrombin in the presence of different heparins and skeletal muscle myosin or cardiac myosin was studied by measuring inhibition of each enzyme's chromogenic substrate hydrolysis.

RESULTS AND CONCLUSIONS

Skeletal muscle myosin and cardiac myosin neutralized unfractionated heparin's enhancement of antithrombin's inhibition of purified factor Xa and thrombin. Skeletal muscle myosin also reduced the inhibition of factor Xa and thrombin by antithrombin in the presence of heparan sulfate. These two myosins did not protect factor Xa from antithrombin inhibition when tested in the presence of smaller heparins (eg, low molecular weight heparin, heparin pentasaccharide). This chain length dependence for skeletal muscle myosin's ability to reduce heparin's anticoagulant activity might have potential implications for therapy for patients who experience increases in plasma myosin levels (eg, acute trauma patients). In addition to the chain length, the type and extent of sulfation of glycosaminoglycans influenced the ability of skeletal muscle myosin to neutralize the polysaccharide's ability to enhance antithrombin's activity. In summary, these studies show that skeletal muscle myosin and cardiac myosin can influence antithrombin's anticoagulant activity against factor Xa and thrombin, implying that they may significantly influence the hemostatic balance involving bleeding vs clotting.

Relationships Among Circulating Levels of Hemostasis Inhibitors, Chemokines, Adhesion Molecules, and MRI Characteristics in Multiple Sclerosis

Background: Several studies suggested cross talk among components of hemostasis, inflammation, and immunity pathways in the pathogenesis, neurodegeneration, and occurrence of cerebral microbleeds (CMBs) in multiple sclerosis (MS).

Objectives: This study aimed to evaluate the combined contribution of the hemostasis inhibitor protein C (PC) and chemokine C-C motif ligand 18 (CCL18) levels to brain atrophy in MS and to identify disease-relevant correlations among circulating levels of hemostasis inhibitors, chemokines, and adhesion molecules, particularly in CMB occurrence in MS.

Methods: Plasma levels of hemostasis inhibitors (ADAMTS13, PC, and PAI1), CCL18, and soluble adhesion molecules (sNCAM, sICAM1, sVCAM1, and sVAP1) were evaluated by multiplex in 138 MS patients [85 relapsing-remitting (RR-MS) and 53 progressive (P-MS)] and 42 healthy individuals (HI) who underwent 3-T MRI exams. Association of protein levels with MRI outcomes was performed by regression analysis. Correlations among protein levels were assessed by partial correlation and Pearson's correlation.

Results: In all patients, regression analysis showed that higher PC levels were associated with lower brain volumes, including the brain parenchyma (p = 0.002), gray matter (p < 0.001), cortex (p = 0.001), deep gray matter (p = 0.001), and thalamus (p = 0.001). These associations were detectable in RR-MS but not in P-MS patients. Higher CCL18 levels were associated with higher T2-lesion volumes in all MS patients (p = 0.03) and in the P-MS (p = 0.003). In the P-MS, higher CCL18 levels were also associated with lower volumes of the gray matter (p = 0.024), cortex (p = 0.043), deep gray matter (p = 0.029), and thalamus (p = 0.022). PC-CCL18 and CCL18-PAI1 levels were positively correlated in both MS and HI, PC–sVAP1 and PAI1–sVCAM1 only in MS, and PC–sICAM1 and PC–sNCAM only in HI. In MS patients with CMBs (n = 12), CCL18–PAI1 and PAI1–sVCAM1 levels were better correlated than those in MS patients without CMBs, and a novel ADAMTS13–sVAP1 level correlation (r = 0.78, p = 0.003) was observed.

Conclusions: Differences between clinical phenotype groups in association of PC and CCL18 circulating levels with MRI outcomes might be related to different aspects of neurodegeneration. Disease-related pathway dysregulation is supported by several protein level correlation differences between MS patients and HI. The integrated analysis of plasma proteins and MRI measures provide evidence for new relationships among hemostasis, inflammation, and immunity pathways, relevant for MS and for the occurrence of CMBs.

Low total cholesterol and high density lipoprotein are independent predictors of poor outcomes following aneurysmal subarachnoid hemorrhage: A preliminary report

INTRODUCTION

Aneurysmal subarachnoid hemorrhage (aSAH) is devastating, with delayed cerebral ischemia (DCI) significantly contributing to the high morbidity and mortality rates. Cholesterol has been studied as a measure of nutritional status in other neurological pathologies, but reports examining cholesterol's effects on aSAH outcomes are sparse. This study aimed to elucidate the effect of low total cholesterol (TC) and high density lipoprotein (HDL) on mortality and DCI following aSAH.

METHODS

We performed a retrospective cohort study at a quaternary academic medical center between June 2014 and July 2018. All patients had aSAH confirmed by digital subtraction angiography and had TC measured on admission. Primary outcomes were mortality and DCI. Secondary outcome was radiographic vasospasm. Univariate and multivariate logistic regressions were performed.

RESULTS

There were 75 aSAH patients, with an average age of 58.7 ± 1.7 (range: 14-89) and Hunt & Hess score of 2.8 ± 0.1, included for analysis. Those with a low TC < 160 mg/dL had 3 times increased odds of DCI (OR = 3.4; 95 %CI: 1.3-9.0; p = 0.0175) and a nearly 5 times increased odds of death (OR = 4.9; 95 %CI: 1.1-18.3; p = 0.0339). Low HDL < 40 mg/dL was associated with 12 times increased odds of DCI (OR = 12.3; 95 %CI: 2.7-56.4; p = 0.0003) but no significant differences in death (p = 0.2205). In multivariate analysis, low TC was an independent risk factor for increased mortality (OR = 5.6; 95 %CI: 1.2-27.6; p = 0.0335) while low HDL was associated with increased risk for DCI (OR = 17.9; 95 %CI: 3.1-104.4; p = 0.0013). There was no effect of TC or HDL on radiographic vasospasm.

CONCLUSIONS

Low TC and HDL are independent predictors of increased mortality and DCI, respectively, following aSAH. Low TC and HDL may be markers of poor overall health, in addition to having some pathophysiological effect on cerebral vasculature. These results may have practical implications for the improvement of aSAH prognostication and management.

Humoral Immunity Against HDL Particle: A New Perspective in Cardiovascular Diseases?

BACKGROUND

Autoimmune diseases are closely associated with cardiovascular diseases (CVD). Over the last decades, the comprehension of atherosclerosis, the principal initiator of CVD, evolved from a lipidcentered disease to a predominant inflammatory and immune response-driven disease displaying features of autoimmunity against a broad range of auto-antigens, including lipoproteins. Among them, high density lipoproteins (HDL) are important actors of cholesterol transport and bear several anti-atherogenic properties, raising a growing interest as therapeutic targets to decrease atherosclerosis and CVD burden, with nevertheless rather disappointing results so far. Reflecting HDL composition complexity, autoimmune responses and autoantibodies against various HDL components have been reported.

RESULTS

In this review, we addressed the important complexity of humoral autoimmunity towards HDL and particularly how this autoimmune response could help improving our understanding of HDL biological implication in atherosclerosis and CVD. We also discussed several issues related to specific HDL autoantibody subclasses characteristics, including etiology, prognosis and pathological mechanisms according to Rose criteria.

CONCLUSION

Finally, we addressed the possible clinical value of using these antibodies not only as potential biomarkers of atherogenesis and CVD, but also as a factor potentially mitigating the benefit of HDL-raising therapies.

High-density lipoprotein cholesterol concentration and acute kidney injury after noncardiac surgery

Background

Abnormal High-density Lipoprotein Cholesterol Concentration is closely related to postoperative acute kidney injury (AKI) after cardiac surgeries. The purpose of this study was to analyze the relationship between High-density Lipoprotein Cholesterol Concentration and acute kidney injury after non-cardiac surgeries.

Method

This was a single-center cohort study for elective non-cardiac non-kidney surgery from January 1, 2012, to December 31, 2017. The endpoint was the occurrence of acute kidney injury (AKI) 7 days postoperatively in the hospital. Preoperative serum High-density Lipoprotein Cholesterol Concentration was examined by multivariate logistic regression models before and after propensity score weighting analysis.

Results

Of the 74,284 surgeries, 4.4% (3159 cases) suffered acute kidney injury. The odds ratio for HDL (0.96–1.14 as reference, < 0.96, 1.14–1.35, > 1.35) was 1.28 (1.14–1.41), P < 0.001; 0.91 (0.80–1.03), P = 0.150; 0.75 (0.64–0.85), P < 0.001, respectively. Using a dichotomized cutoff point for propensity analysis, Preoperative serum HDL <  1.03 mmol/L (> 1.03 as reference) was associated with increased risk of postoperative AKI, with odds ratio 1.40 (1.27 ~ 1.52), P < 0.001 before propensity score weighting, and 1.32 (1.21–1.46), P < 0.001 after propensity score weighting. Sensitivity analysis with other cut values of HDL showed similar results.

Conclusions

Using multivariate regression analyses before and after propensity score weighting, in addition to multiple sensitivity analysis methods, this study found that following non-cardiac surgery, low HDL cholesterol levels were independent risk factors for AKI.

High-density lipoproteins during sepsis: from bench to bedside

High-density lipoproteins (HDLs) represent a family of particle characterized by the presence of apolipoprotein A-I (apoA-I) and by their ability to transport cholesterol from peripheral tissues back to the liver conferring them a cardioprotective function. HDLs also display pleiotropic properties including antioxidant, anti-apoptotic, anti-thrombotic, anti-inflammatory, or anti-infectious functions. Clinical data demonstrate that HDL cholesterol levels decrease rapidly during sepsis and that these low levels are correlated with morbi-mortality. Experimental studies emphasized notable structural and functional modifications of HDL particles in inflammatory states, including sepsis. Finally, HDL infusion in animal models of sepsis improved survival and provided a global endothelial protective effect. These clinical and experimental studies reinforce the potential of HDL therapy in human sepsis. In this review, we will detail the different effects of HDLs that may be relevant under inflammatory conditions and the lipoprotein changes during sepsis and we will discuss the potentiality of HDL therapy in sepsis.

Plasma fibrin clot proteomics in healthy subjects: Relation to clot permeability and lysis time

BACKGROUND

Little is known about fibrin clot composition in relation to its structure and lysability. We investigated plasma clots protein composition and its associations with clot properties.

METHODS

We studied 20 healthy subjects aged 31-49 years in whom plasma fibrin clot permeability (K_s) and clot lysis time (CLT) were determined. A proteomic analysis of plasma fibrin clots was based on quantitative liquid chromatography-mass spectrometry.

RESULTS

Among 494 clot-bound proteins identified in all clots, the highest concentrations were for fibrinogen chains (about 64% of the clot mass) and fibronectin (13%). α₂-antiplasmin (2.7%), factor XIIIA (1.2%), complement component C3 (1.2%), and histidine-rich glycoprotein (HRG, 0.61%) were present at relatively high concentrations. Proteins present in concentrations <0.5% included (pro)thrombin, plasminogen, apolipoproteins, or platelet factor 4 (PF4). Fibrinogen-α and -γ chains were associated with age, while body-mass index with clot-bound apolipoproteins (all p < .05). K_s correlated with fibrinogen-γ and PF4 amounts within plasma clots. CLT was associated with fibrinogen-α and -γ, PF4, and HRG (all p < .05).

CONCLUSIONS

This study is the first to show associations of two key measures of clot properties with protein content within plasma clots, suggesting that looser fibrin clots with enhanced lysability contain less fibrinogen-γ chain, platelet-derived PF4, and HRG.

SIGNIFICANCE

Our study for the first time suggests that more permeable fibrin clots with enhanced lysability contain less fibrinogen-γ chain, platelet-derived factor 4, and histidine-rich glycoprotein, which is related to accelerated clot lysis. The current findings might have functional consequences regarding clot structure, stability, and propagation of thrombin generation, and detailed proteomic analysis of clots in various disorders opens new perspective for coagulation and fibrin research.

Relationship Between HDL Functional Characteristics and Cardiovascular Health and Potential Impact of Dietary Patterns: A Narrative Review

Cardiovascular disease is a leading cause of death around the world. Overall diet quality and dietary behaviors are core contributors to metabolic health. While therapeutic targets have traditionally focused on levels of lipoprotein cholesterol when evaluating cardiovascular risk, current perspectives on high-density lipoprotein (HDL) have shifted to evaluating the functionality of this lipoprotein particle. Effects of diet on cardiovascular health are mediated through multiple pathways, but the impact on HDL composition and function deserves greater attention. Potential areas of investigation involve changes in particle characteristics, distribution, microRNA cargo, and other functional changes such as improvements to cholesterol efflux capacity. Various dietary patterns like the Mediterranean diet and Dietary Approaches to Stop Hypertension (DASH) diet have beneficial effects on cardiovascular health and may prevent cardiovascular events. These healthful dietary patterns tend to be rich in plant-based foods, with cardiovascular benefits likely resulting from synergistic effects of the individual dietary components. The purpose of this review is to summarize current perspectives on selected functions of HDL particles and how various dietary patterns affect cardiovascular health biomarkers, with a focus on HDL functionality.

High-density lipoprotein cholesterol for the prediction of mortality in cirrhosis with portal vein thrombosis: a retrospective study

BACKGROUND

Lipid profiles disorders frequently occur in patients with chronic liver diseases, and the mortality of cirrhosis complicated with portal vein thrombosis (PVT) remains high. Research identifying simple and objective prognosis indicators for cirrhotic PVT has been limited. The aim of the present study was to investigate the association between lipid profiles and liver function, which may help predict the 1-year mortality in non-malignant cirrhosis with PVT.

METHODS

A retrospective cohort of 117 subjects with non-malignant cirrhotic PVT was conducted. The primary indicators of lipid profiles included triglyceride, cholesterol, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol. Correlations of lipid profiles with liver function tests, the Child-Turcotte-Pugh (CTP) score and the model for end-stage liver disease (MELD) score were investigated. The relationship between lipid profiles and 1-year mortality was assessed using the area under the receiver operating characteristic curves (AUROC). Logistic regression models were established to confirm the association between HDL-C and mortality.

RESULTS

The level of HDL-C was significantly decreased in non-survivors (p < 0.01) and patients with more severe liver damage stages (CTP p < 0.001; MELD p < 0.001). There was no significant difference in the HDL-C level among patients with different severities of PVT (p = 0.498). The level of HDL-C was positively correlated with albumin (p < 0.001, R = 0.438) and platelet (p = 0.022, R = 0.212) levels. The level of HDL-C was negatively correlated with bilirubin (p < 0.001, R = - 0.319), C-reactive protein (p < 0.001, R = - 0.342), the aspartate aminotransferase to alanine aminotransferase ratio (p < 0.0.1, R = - 0.237), the CTP score (p < 0.001, R = - 0.397) and the MELD score (p < 0.001, R = - 0.406). The 1-year mortality rate was 12.8%. The AUROC of HDL-C for the prediction of 1-year mortality in this population was 0.744 (p < 0.01, 95%CI 0.609-0.879). The level of HDL-C was independently associated with mortality by multivariate logistic regression models.

CONCLUSIONS

The HDL-C level significantly decreases with the deterioration of liver function, which may serve as a potential indicator for the prognosis of non-malignant cirrhotic patients with PVT.

Current Therapies Focused on High-Density Lipoproteins Associated with Cardiovascular Disease

High-density lipoproteins (HDL) comprise a heterogeneous family of lipoprotein particles divided into subclasses that are determined by density, size and surface charge as well as protein composition. Epidemiological studies have suggested an inverse correlation between High-density lipoprotein-cholesterol (HDL-C) levels and the risk of cardiovascular diseases and atherosclerosis. HDLs promote reverse cholesterol transport (RCT) and have several atheroprotective functions such as anti-inflammation, anti-thrombosis, and anti-oxidation. HDLs are considered to be atheroprotective because they are associated in serum with paraoxonases (PONs) which protect HDL from oxidation. Polyphenol consumption reduces the risk of chronic diseases in humans. Polyphenols increase the binding of HDL to PON1, increasing the catalytic activity of PON1. This review summarizes the evidence currently available regarding pharmacological and alternative treatments aimed at improving the functionality of HDL-C. Information on the effectiveness of the treatments has contributed to the understanding of the molecular mechanisms that regulate plasma levels of HDL-C, thereby promoting the development of more effective treatment of cardiovascular diseases. For that purpose, Scopus and Medline databases were searched to identify the publications investigating the impact of current therapies focused on high-density lipoproteins.

Metabolic syndrome and psoriasis: a study in 97 patients

BACKGROUND

Psoriasis is associated with higher prevalence of metabolic syndrome (MS). The prevalence of MS varies according to the studied population as it suffers influence of genetics, aging, sedentary behaviour and diet.

OBJECTIVE

To study the prevalence of MS in local psoriasis patients and the influence of psoriasis variables on its appearance.

METHODS

A group of 97 psoriasis patients were studied for MS and compared with 97 controls. Psoriasis type, nail involvement, psoriasis extension measured by PASI (Psoriasis Area and Severity Index) were obtained through physical examination and history of previous myocardial infarction, angina and stroke were obtained through chart review.

RESULTS

Comparison of MS prevalence in psoriasis patients (49.4%) with controls (35.0%) showed difference with p=0.04; OR=1.8 (95%CI=1.02-3.23). Patients with psoriasis had higher body mass index (p=0.02), higher systolic blood pressure (p=0.007), lower HDL cholesterol (p=0.01), higher glucose (p=0.04), higher waist circumference (p=0.003) and more angina pectoris (p=0.03;OR=2.5; 95% 0=1.04-6.15) than controls. When psoriasis sample with and without MS were compared, those with MS were older (p=0.0004), had disease onset at older age (p=0.02), more tobacco exposure (p=0.02), and a tendency to have less scalp involvement (p=0.06) in univariate analysis. Logistic regression showed that only age and scalp involvement were independently associated with MS in the psoriasis sample.

CONCLUSION

In our psoriasis sample, MS prevalence is high and the items that deserve more attention are central obesity, low HDL, hypertension and smoking habits. In the psoriasis group, MS was associated independently with older age and less scalp involvement.

Plasma levels of high density lipoprotein cholesterol and outcomes in chronic thromboembolic pulmonary hypertension

Background

High Density Lipoprotein Cholesterol (HDL-C) has various anti-inflammatory, anti-atherogenic, anti-oxidant and anti-coagulant properties that improve vascular function. The utility of HDL-C as a biomarker of severity and predictor of survival was described in patients with pulmonary arterial hypertension (PAH). No prior study has assessed the utility of HDL-C in patients with Chronic Thromboembolic Pulmonary Hypertension (CTEPH).

Objectives

We aim to measure HDL-C levels in CTEPH patients and compare it to those in PAH patients and controls and determine HDL-C associations with markers of disease severity, hemodynamics and mortality in CTEPH.

Methods

We retrospectively included patients with CTEPH, identified from the Cleveland Clinic Pulmonary Hypertension Registry. All patients had right heart catheterization (RHC) and imaging studies consistent with CTEPH. We collected demographics, co-morbidities, baseline laboratory data including plasma HDL-C, six-minute walk test (6MWT), echocardiography and RHC. HDL-C levels were compared to a cohort of patients with cardiovascular risk factors and a previously published PAH cohort.

Results

HDL-C levels were available for 90 patients with CTEPH (age: 57.4±13.9 years; female 40%), 69 patients with PAH (age: 46.7±12.8 years; female 90%) and 254 control subjects (age: 56.7±13 years; female 48%). HDL-C levels in CTEPH patients were lower compared to controls and higher compared to PAH patients (median, IQR: CTEPH: 44, 34–57 mg/dl; PAH: 35.3, 29–39 mg/dl; Control: 49, 40–60 mg/dl; p < 0.01 for both pairwise comparisons). In CTEPH, higher HDL-C was associated with decreased prevalence of right ventricular dilation on echocardiography (p = 0.02). 57 patients with CTEPH underwent pulmonary thromboendarterectomy, higher HDL-C was associated with a larger decrement in postoperative pulmonary vascular resistance (PVR) (r = 0.37, p = 0.049). HDL-C was not associated with mortality or other markers of disease severity.

Conclusions

HDL-C levels in CTEPH patients were lower compared to control subjects, but higher compared to PAH patients. Higher HDL-C in CTEPH was associated with less right ventricular dilation and greater decrement in postoperative PVR. These data suggest that HDL-C may be a useful marker of small vessel disease in CTEPH.

Proteome of human plasma very low-density lipoprotein and low-density lipoprotein exhibits a link with coagulation and lipid metabolism

Apart from transporting lipids through the body, the human plasma lipoproteins very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) are also thought to serve as a modality for intra-organismal protein transfer, shipping proteins with important roles in inflammation and thrombosis from the site of synthesis to effector locations. To better understand the role of VLDL and LDL in the transport of proteins, we applied a combination of LTQ ORBITRAP-XL (nLC-MS/MS) with both in-SDS-PAGE gel and in-solution tryptic digestion of pure and defined VLDL and LDL fractions. We identified the presence of 95 VLDL-and 51 LDL-associated proteins including all known apolipoproteins and lipid transport proteins, and intriguingly a set of coagulation proteins, complement system and anti-microbial proteins. Prothrombin, protein S, fibrinogen γ, PLTP, CETP, CD14 and LBP were present on VLDL but not on LDL. Prenylcysteine oxidase 1, dermcidin, cathelicidin antimicrobial peptide, TFPI-1 and fibrinogen α chain were associated with both VLDL and LDL. Apo A-V is only present on VLDL and not on LDL. Collectively, this study provides a wealth of knowledge on the protein constituents of the human plasma lipoprotein system and strongly supports the notion that protein shuttling through this system is involved in the regulation of biological processes. Human diseases related to proteins carried by VLDL and LDL can be divided in three major categories: 1 – dyslipidaemia, 2 – atherosclerosis and vascular disease, and 3 – coagulation disorders.

Pulmonary endothelial cell DNA methylation signature in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a severe and incurable pulmonary vascular disease. One of the primary origins of PAH is pulmonary endothelial dysfunction leading to vasoconstriction, aberrant angiogenesis and smooth muscle cell proliferation, endothelial-to-mesenchymal transition, thrombosis and inflammation. Our objective was to study the epigenetic variations in pulmonary endothelial cells (PEC) through a specific pattern of DNA methylation. DNA was extracted from cultured PEC from idiopathic PAH (n = 11), heritable PAH (n = 10) and controls (n = 18). DNA methylation was assessed using the Illumina HumanMethylation450 Assay. After normalization, samples and probes were clustered according to their methylation profile. Differential clusters were functionally analyzed using bioinformatics tools. Unsupervised hierarchical clustering allowed the identification of two clusters of probes that discriminates controls and PAH patients. Among 147 differential methylated promoters, 46 promoters coding for proteins or miRNAs were related to lipid metabolism. Top 10 up and down-regulated genes were involved in lipid transport including ABCA1, ABCB4, ADIPOQ, miR-26A, BCL2L11. NextBio meta-analysis suggested a contribution of ABCA1 in PAH. We confirmed ABCA1 mRNA and protein downregulation specifically in PAH PEC by qPCR and immunohistochemistry and made the proof-of-concept in an experimental model of the disease that its targeting may offer novel therapeutic options. In conclusion, DNA methylation analysis identifies a set of genes mainly involved in lipid transport pathway which could be relevant to PAH pathophysiology.

High density lipoproteins are modulators of protease activity: Implications in inflammation, complement activation, and atherothrombosis

High density lipoproteins (HDL) represent a compositionally diverse population of particles in the circulation, containing a wide variety of lipids and proteins. Gene ontology functional analysis of the 96 commonly identified HDL binding proteins reveals that almost half of these proteins are either proteases or have known roles in protease regulation. Here, we discuss the activities of some of these proteins in regard to their roles in regulating proteases involved in inflammation, coagulation, and complement activation, particularly in the context of atherosclerosis. The overall goal of this review is to discuss potential functional roles of HDL in protease regulatory pathways based on current literature and known functions of HDL binding proteins and to promote the consideration of HDL as a global modulator of proteolytic equilibrium.

HDL cholesterol: reappraisal of its clinical relevance

Background

While several lines of evidence prove that elevated concentrations of low-density lipoproteins (LDL) causally contribute to the development of atherosclerosis and its clinical consequences, high-density lipoproteins are still widely believed to exert atheroprotective effects. Hence, HDL cholesterol (HDL-C) is in general still considered as “good cholesterol”. Recent research, however, suggests that this might not always be the case and that a fundamental reassessment of the clinical significance of HDL-C is warranted.

Method

This review article is based on a selective literature review.

Results

In individuals without a history of cardiovascular events, low concentrations of HDL-C are inversely associated with the risk of future cardiovascular events. This relationship may, however, not apply to patients with metabolic disorders or manifest cardiovascular disease. The classical function of HDL is to mobilise cholesterol from extrahepatic tissues for delivery to the liver for excretion. These roles in cholesterol metabolism as well as many other biological functions of HDL particles are dependent on the number as well as protein and lipid composition of HDL particles. They are poorly reflected by the HDL-C concentration. HDL can even exert negative vascular effects, if its composition is pathologically altered. High serum HDL-C is therefore no longer regarded protective. In line with this, recent pharmacological approaches to raise HDL-C concentration have not been able to show reductions of cardiovascular outcomes.

Conclusion

In contrast to LDL cholesterol (LDL-C), HDL-C correlates with cardiovascular risk only in healthy individuals. The calculation of the ratio of LDL-C to HDL-C is not useful for all patients. Low HDL-C should prompt examination of additional metabolic and inflammatory pathologies. An increase in HDL-C through lifestyle change (smoking cessation, physical exercise) has positive effects and is recommended. However, HDL-C is currently not a valid target for drug therapy.

[Clinical importance of HDL cholesterol]

BACKROUND

Each year 16-17 million determinations of high-density lipoprotein cholesterol (HDL-C) are conducted and interpreted in Germany. Recently acquired data have led to a fundamental reassessment of the clinical significance of HDL-C.

METHOD

This review article is based on a selective literature search.

RESULTS

Low HDL‑C levels usually indicate an increased cardiovascular risk, particularly in primary prevention but the epidemiological relationship between HDL‑C and the risk is complex. The HDL plays a role in the back transport and excretion of cholesterol; however, the biological functions of HDL are dependent on the protein and lipid composition, which is not reflected by the HDL‑C concentration. If the composition of HDL is pathologically altered it can also exert negative vascular effects.

CONCLUSION

Compared with low-density lipoprotein cholesterol (LDL-C), HDL‑C is of secondary importance for cardiovascular risk stratification and the calculation of the LDL-C:HDL‑C ratio is not useful for all patients. Low HDL‑C levels should prompt a search for additional metabolic and inflammatory pathologies. An increase in HDL‑C through lifestyle changes (e.g. smoking cessation and physical exercise) has positive effects and is recommended; however, HDL‑C is currently not a valid target for drug therapy.

Dysfunctional high-density lipoproteins in coronary heart disease: implications for diagnostics and therapy

Low plasma levels of high-density lipoprotein (HDL) cholesterol are associated with increased risks of coronary heart disease. HDL mediates cholesterol efflux from macrophages for reverse transport to the liver and elicits many anti-inflammatory and anti-oxidative activities which are potentially anti-atherogenic. Nevertheless, HDL has not been successfully targeted by drugs for prevention or treatment of cardiovascular diseases. One potential reason is the targeting of HDL cholesterol which does not capture the structural and functional complexity of HDL particles. Hundreds of lipid species and dozens of proteins as well as several microRNAs have been identified in HDL. This physiological heterogeneity is further increased in pathologic conditions due to additional quantitative and qualitative molecular changes of HDL components which have been associated with both loss of physiological function and gain of pathologic dysfunction. This structural and functional complexity of HDL has prevented clear assignments of molecules to the functions of normal HDL and dysfunctions of pathologic HDL. Systematic analyses of structure-function relationships of HDL-associated molecules and their modifications are needed to test the different components and functions of HDL for their relative contribution in the pathogenesis of atherosclerosis. The derived biomarkers and targets may eventually help to exploit HDL for treatment and diagnostics of cardiovascular diseases.

Primary Low Level of High-Density Lipoprotein Cholesterol and Risks of Coronary Heart Disease, Cardiovascular Disease, and Death: Results From the Multi-Ethnic Study of Atherosclerosis

Prior studies observing associations between low levels of high-density lipoprotein (HDL) cholesterol and cardiovascular disease (CVD) have often been conducted among persons with metabolic or other lipid abnormalities. In this study, we investigated the association between primary low HDL cholesterol and coronary heart disease (CHD), CVD, and all-cause death after adjustment for confounders in the Multi-Ethnic Study of Atherosclerosis (MESA). Participants who were free of clinical CVD were recruited from 6 US research centers from 2000 to 2002 and followed for a median duration of 10.2 years. We defined "primary low HDL cholesterol" as HDL cholesterol level <40 mg/dL (men) or <50 mg/dL (women), triglyceride level <100 mg/dL, and low-density lipoprotein cholesterol level <100 mg/dL (n = 158). We defined an "optimal" lipid profile as HDL cholesterol ≥40 mg/dL (men) or ≥50 mg/dL (women) and triglycerides and low-density lipoprotein cholesterol <100 mg/dL (n = 780). For participants with primary low HDL cholesterol versus those with an optimal lipid profile, adjusted hazard ratios for total CHD, CVD, and death were 2.25 (95% confidence interval (CI): 1.20, 4.21; P = 0.011), 1.93 (95% CI: 1.11, 3.34; P = 0.020), and 1.11 (95% CI: 0.67, 1.84; P = 0.69), respectively. Participants with primary low HDL cholesterol had higher risks of CHD and CVD than participants with optimal lipid profiles but no difference in survival after a median 10.2 years of follow-up.

Proteomic and lipidomic analyses of paraoxonase defined high density lipoprotein particles: Association of paraoxonase with the anti-coagulant, protein S

PURPOSE

Characterizing high density lipoprotein (HDL) particles and their relevance to HDL function is a major research objective. One aim is to identify functionally distinct particles. To try to limit both functional and compositional heterogeneity the present study focused on paraoxonase-1 (PON1) as a target for isolation of a minor HDL subfraction.

EXPERIMENTAL DESIGN

Immunoaffinity techniques were applied to isolate PON1-containing HDL (P-HDL) and total HDL (T-HDL), which were subsequently characterized and compared.

RESULTS

Analyses of the lipidomes showed significant differences between the fractions in the relative concentrations of individual lipid subspecies, notably reduced levels of unsaturated lysophosphatidylcholine (p < 0.05) in P-HDL (reflected in a significantly reduced total lysophosphatidylcholine polyunsaturated fatty acid content, p < 0.004). Significant differences were also observed for the proteomes. P-HDL was highly enriched in the anti-coagulant, vitamin K activated protein S (prot S) (p < 0.0001), and alpha2 macroglobulin (p < 0.01), compared to T-HDL. Conversely, procoagulant proteins kininogen 1 and histidine-rich glycoprotein were largely excluded from P-HDL. Immunoabsorption of PON1 from plasma significantly reduced prot S anti-coagulant activity.

CONCLUSIONS AND CLINICAL RELEVANCE

The P-HDL lipidome and proteome showed significant differences from T-HDL. Enrichment in anti-coagulation proteins indicates complementary functionalities within P-HDL particles and underlines their anti-atherosclerotic potential.

Bioactive Egg Components and Inflammation

Inflammation is a normal acute response of the immune system to pathogens and tissue injury. However, chronic inflammation is known to play a significant role in the pathophysiology of numerous chronic diseases, such as cardiovascular disease, type 2 diabetes mellitus, and cancer. Thus, the impact of dietary factors on inflammation may provide key insight into mitigating chronic disease risk. Eggs are recognized as a functional food that contain a variety of bioactive compounds that can influence pro- and anti-inflammatory pathways. Interestingly, the effects of egg consumption on inflammation varies across different populations, including those that are classified as healthy, overweight, metabolic syndrome, and type 2 diabetic. The following review will discuss the pro- and anti-inflammatory properties of egg components, with a focus on egg phospholipids, cholesterol, the carotenoids lutein and zeaxanthin, and bioactive proteins. The effects of egg consumption of inflammation across human populations will additionally be presented. Together, these findings have implications for population-specific dietary recommendations and chronic disease risk.

Effect of anti-ApoA-I antibody-coating of stents on neointima formation in a rabbit balloon-injury model

Background and Aims

Since high-density lipoprotein (HDL) has pro-endothelial and anti-thrombotic effects, a HDL recruiting stent may prevent restenosis. In the present study we address the functional characteristics of an apolipoprotein A-I (ApoA-I) antibody coating in vitro. Subsequently, we tested its biological performance applied on stents in vivo in rabbits.

Materials and Methods

The impact of anti ApoA-I- versus apoB-antibody coated stainless steel discs were evaluated in vitro for endothelial cell adhesion, thrombin generation and platelet adhesion. In vivo, response to injury in the iliac artery of New Zealand white rabbits was used as read out comparing apoA-I-coated versus bare metal stents.

Results

ApoA-I antibody coated metal discs showed increased endothelial cell adhesion and proliferation and decreased thrombin generation and platelet adhesion, compared to control discs. In vivo, no difference was observed between ApoA-I and BMS stents in lumen stenosis (23.3±13.8% versus 23.3±11.3%, p=0.77) or intima surface area (0.81±0.62 mm² vs 0.84±0.55 mm², p=0.85). Immunohistochemistry also revealed no differences in cell proliferation, fibrin deposition, inflammation and endothelialization.

Conclusion

ApoA-I antibody coating has potent pro-endothelial and anti-thrombotic effects in vitro, but failed to enhance stent performance in a balloon injury rabbit model in vivo.

Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy

BACKGROUND

Patients with schizophrenia are at increased risk of venous thromboembolism. The mechanisms underlying this association are poorly understood.

AIMS

We investigated whether there is a global hypercoagulable state in patients with schizophrenia utilising the overall haemostatic potential (OHP) assay which assesses overall coagulation potential (OCP), haemostatic potential (OHP) and fibrinolytic potential (OFP).

METHOD

Citrated plasma was collected for OHP assays from patients with schizophrenia on long-term antipsychotic treatment and compared with healthy age- and sex-matched controls. Time courses of fibrin formation and degradation were measured by spectrophotometry (absorption of 405nm) after the addition of tissue factor and tissue plasminogen activator to plasma.

RESULTS

Ninety patients with schizophrenia (antipsychotic treatment-15.9±9.7years) and 30 controls were recruited. Patients with schizophrenia had higher rates of smoking and levels of inflammatory markers (high-sensitivity C-reactive protein and neutrophil-to-lymphocyte ratio) than controls. Whilst D-dimer, fibrinogen and platelet count did not differ between patients with schizophrenia and controls, the OCP (54.0±12.6 vs 45.9±9.1, p=0.002) and OHP (12.6±5.8 vs 7.2±3.7, p<0.001) were higher, and OFP was lower (76.6±9.8% vs 84.9±6.4%, p<0.001) in patients with schizophrenia, implying both a hypercoagulable and hypofibrinolytic state in these patients. Importantly, abnormalities in overall coagulation were independently predicted by levels of plasminogen-activator-inhibitor-1, fibrinogen, platelet count, inflammatory markers and plasma triglycerides, suggesting a multifactorial aetiology.

CONCLUSION

Patients with schizophrenia have evidence of a global hypercoagulable and hypofibrinolytic state which may contribute to their increased risk of venous thromboembolism.

HDL and atherothrombotic vascular disease

High-density lipoproteins (HDLs) exert many beneficial effects which may help to protect against the development or progression of atherosclerosis or even facilitate lesion regression. These activities include promoting cellular cholesterol efflux, protecting low-density lipoproteins (LDLs) from modification, preserving endothelial function, as well as anti-inflammatory and antithrombotic effects. However, questions remain about the relative importance of these activities for atheroprotection. Furthermore, the many molecules (both lipids and proteins) associated with HDLs exert both distinct and overlapping activities, which may be compromised by inflammatory conditions, resulting in either loss of function or even gain of dysfunction. This complexity of HDL functionality has so far precluded elucidation of distinct structure-function relationships for HDL or its components. A better understanding of HDL metabolism and structure-function relationships is therefore crucial to exploit HDLs and its associated components and cellular pathways as potential targets for anti-atherosclerotic therapies and diagnostic markers.

Re-evaluation of the anticoagulant properties of high-density lipoprotein-brief report

OBJECTIVE

This study was conducted to resolve the striking controversy between our previous report that high-density lipoprotein (HDL) enhances activated protein C (APC)/protein S anticoagulant actions and a subsequent, contradicting report that HDL lacks this activity.

APPROACH AND RESULTS

When fresh HDL preparations from 2 laboratories were subjected to Superose 6 column chromatography, fractions containing HDL-enhanced APC:protein S anticoagulant actions in clotting assays, thereby validating our previous report. Moreover, the ability of HDL to enhance the anticoagulant actions of APC:protein S was neutralized by anti-apoAI antibodies, further indicating that the activity is because of HDL particles and not because of contaminating phospholipid vesicles. Density gradient subfractionation studies of HDL showed that large HDL subfractions (densities between 1.063 and 1.125 g/mL) contained the APC:protein S-enhancing activity. Fresh HDL stored at 4°C gradually lost its anticoagulant enhancing activity for 14 days, indicating moderate instability in this activity of purified HDL.

CONCLUSIONS

These studies conclusively demonstrate that freshly prepared HDL fractions possess anticoagulant activity. Fractions from Superose 6 columns that contain HDL reproducibly enhance APC:protein S anticoagulant activity, consistent with the hypothesis that HDL has antithrombotic activity and with the observation that low HDL levels are found in male venous thrombosis patients. Understanding the basis for this activity could lead to novel therapeutic approaches to regulate venous thrombosis.

Beginning to understand high-density lipoproteins

This article reconciles the classic view of high-density lipoproteins (HDL) associated with low risk for cardiovascular disease (CVD) with recent data (genetics studies and randomized clinical trials) casting doubt over the widely accepted beneficial role of HDL regarding CVD risk. Although HDL cholesterol has been used as a surrogate measure to investigate HDL function, the cholesterol content in HDL particles is not an indicator of the atheroprotective properties of HDL. Thus, more precise measures of HDL metabolism are needed to reflect and account for the beneficial effects of HDL particles. Current and emerging therapies targeting HDL are discussed.

Protein Z-deficiency is associated with enhanced neointima formation and inflammatory response after vascular injury in mice

BACKGROUND

Protein Z (PZ) is a vitamin K-dependent coagulation factor without catalytic activity. Evidence points towards PZ as an independent risk factor for the occurrence of human atherosclerotic vascular diseases. The aim of this study was to investigate the role of PZ in vascular arterial disease.

MATERIAL AND METHODS

PZ-deficient (PZ(-/-)) mice and their wild-type littermates (PZ(+/+)) were subjected to unilateral carotid artery injury by using ferric chloride and dissected 21 days thereafter for histological analysis. Human aortic smooth muscle cells (SMC) were used for in vitro wound healing assay to assess the influence of PZ on SMC migration and for cell proliferation studies.

RESULTS

Morphometric analysis of neointima formation revealed a significantly increased area and thickness of the neointima and subsequently increased luminal stenosis in carotid arteries of PZ(-/-) mice compared to PZ(+/+) mice (p < 0.05, n = 9). Immunohistochemical analysis of neointima lesion composition revealed significantly higher numbers of PCNA-positive and α-SMA-positive cells in the neointima of PZ(-/-) mice. Furthermore, PZ showed an anti-migratory potency in in vitro wound healing assay with SMCs, while no effect of PZ on SMC proliferation was detectable. Conclusion: PZ contributes to a reduced neointima formation after vascular injury, underlining the modulatory role of the coagulation cascade in vascular homeostasis.

Changes in lipid metabolism and extension of venous thromboembolism

BACKGROUND/AIMS

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are common diseases with a vast number of acquired and congenital risk factors. Disorders of the lipid metabolism are not established risk factors for venous thromboembolism (VTE) so far. However, in recent literature, associations between VTE and the metabolic syndrome, especially with elevated lipid parameters, have been described. The aim of our study was to investigate the association between the extension of VTE and changes in the lipid profile.

METHODS

We included 178 VTE patients in our study; 59 patients had isolated PE, 39 patients had isolated DVT of the leg and 80 patients had both (DVT and PE). Concerning PE, we distinguished between massive and submassive PE. We evaluated plasma lipids and lipoproteins in PE and DVT patients as well as in massive and submassive PE patients.

RESULTS

PE patients had higher levels of plasma triglycerides [median (interquartile range): 162 (109-254) vs. 136.5 (96.5-162) mg/dl, p = 0.047] and lower levels of high-density lipoprotein cholesterol (HDL-C; 52.1 ± 17.2 vs. 63.9 ± 22.7 mg/dl, p = 0.004) than DVT patients. Furthermore, PE patients were significantly older than DVT patients (59.6 ± 16.9 vs. 52.2 ± 15.5 years, p = 0.02). We were not able to find differences in lipid parameters in patients with massive PE compared to those with submassive PE. However, patients with massive PE were more obese than patients with submassive PE (body mass index 29.1 ± 4.6 vs. 26.9 ± 4.9, p = 0.012).

CONCLUSIONS

Lipid parameters and lipoproteins differ between DVT and PE patients. PE patients had higher triglyceride and lower HDL-C levels compared with DVT patients.

Treating low high-density lipoprotein cholesterol: what is the evidence?

Epidemiological studies have shown an inverse association between high-density lipoprotein cholesterol (HDL-C) and cardiovascular disease (CVD) risk. However, genetic and interventional studies have failed to consistently support this relationship. There is an increasing body of evidence that the function of HDL, including its antiatherogenic properties and its reverse cholesterol transport activity, has a greater impact on CVD risk compared with levels of HDL alone. Targeting HDL has become a growing interest. Nevertheless, raising HDL pharmacologically has failed to show a considerable, if any, impact on cardiovascular outcome. Efforts should focus on improving HDL quality in addition to raising HDL levels when developing new therapies. Ongoing and future research will help determine the most safe and effective approach to improve cardiovascular outcome and establish the safety, efficacy and impact on atherosclerosis of the emerging HDL-raising therapies.

Superior in vivo compatibility of hydrophilic polymer coated prosthetic vascular grafts

PURPOSE

Protein adsorption, cell adhesion and graft patency was compared in hydrophilic versus hydrophobic polymer-coated prosthetic vascular grafts. We hypothesize that in vivo compatibility of hydrophilic polymer-coated prosthetic vascular grafts is superior to in vivo compatibility of hydrophobic grafts.

METHODS

A pairwise side-to-side common carotid artery interposition graft was placed eight female landrace goats (mean weight 55 kg). Protein adsorption was assessed using Western Blot in two hydrophilic and two hydrophobic grafts harvested after three days. Graft patency was monitored for 28 days in six goats with continuous wave Doppler ultrasonography. Adherence of endothelial cells, leukocytes and platelets was determined with ELISA and compared between the two graft types after 28 days.

RESULTS

After three days, more ApoA-I, albumin and VEGF and less fibrin adsorbed to hydrophilic grafts. After 28 days, compared to hydrophobic grafts, higher numbers of endothelial cells were present on hydrophilic grafts (P=0.016), and less thrombocytes and leukocytes (P=0.012 and 0.024, respectively). Two out of eight hydrophobic grafts lost patency, while none of the hydrophilic grafts failed (P=0.157).

CONCLUSIONS

Hydrophilic polymer-coated vascular grafts have superior in vivo compatibility when compared to hydrophobic grafts as characterized by reduced platelet and leukocyte adherence as well as higher endothelialization.

Proteomic diversity of high density lipoproteins: our emerging understanding of its importance in lipid transport and beyond

Recent applications of mass spectrometry technology have dramatically increased our understanding of the proteomic diversity of high density lipoproteins (HDL). Depending on the method of HDL isolation, upwards of 85 proteins have been identified, and the list continues to grow. In addition to proteins consistent with traditionally accepted roles in lipid transport, HDL carries surprising constituents, such as members of the complement pathway, protease inhibitors involved in hemostasis, acute-phase response proteins, immune function mediators, and even metal-binding proteins. This compositional diversity fits well with hundreds of studies demonstrating a wide functional pleiotrophy, including roles in lipid transport, oxidation, inflammation, hemostasis, and immunity. This review summarizes the progression of our understanding of HDL proteomic complexity and points out key experimental observations that reinforce the functional diversity of HDL. The possibility of specific HDL subspecies with distinct functions, the evidence supporting this concept, and some of the best examples of experimentally defined HDL subspecies are also discussed. Finally, key challenges facing the field are highlighted, particularly the need to identify and define the function of HDL subspecies to better inform attempts to pharmacologically manipulate HDL for the benefit of cardiovascular disease and possibly other maladies.