Willibald Maier

Mechanisms underlying adverse effects of HDL on eNOS-activating pathways in patients with coronary artery disease

Therapies that raise levels of HDL, which is thought to exert atheroprotective effects via effects on endothelium, are being examined for the treatment or prevention of coronary artery disease (CAD). However, the endothelial effects of HDL are highly heterogeneous, and the impact of HDL of patients with CAD on the activation of endothelial eNOS and eNOS-dependent pathways is unknown. Here we have demonstrated that, in contrast to HDL from healthy subjects, HDL from patients with stable CAD or an acute coronary syndrome (HDLCAD) does not have endothelial antiinflammatory effects and does not stimulate endothelial repair because it fails to induce endothelial NO production. Mechanistically, this was because HDLCAD activated endothelial lectin-like oxidized LDL receptor 1 (LOX-1), triggering endothelial PKCβII activation, which in turn inhibited eNOS-activating pathways and eNOS-dependent NO production. We then identified reduced HDL-associated paraoxonase 1 (PON1) activity as one molecular mechanism leading to the generation of HDL with endothelial PKCβII-activating properties, at least in part due to increased formation of malondialdehyde in HDL. Taken together, our data indicate that in patients with CAD, HDL gains endothelial LOX-1- and thereby PKCβII-activating properties due to reduced HDL-associated PON1 activity, and that this leads to inhibition of eNOS-activation and the subsequent loss of the endothelial antiinflammatory and endothelial repair-stimulating effects of HDL.

Inflammatory Markers at the Site of Ruptured Plaque in Acute Myocardial Infarction Locally Increased Interleukin-6 and Serum Amyloid A but Decreased C-Reactive Protein

Background—Acute myocardial infarction (AMI) is associated with inflammation. However, it remains unclear whether it originates from the ruptured plaque or represents a systemic process. Methods and Results—In 42 patients with AMI, a balloon-based embolization protection device and aspiration catheter (PercuSurge) were used during acute coronary interventions. Samples from the site of the ruptured plaque were taken under distal balloon occlusion. Systemic samples were taken from the aorta. Sera, plaques, and thrombi were analyzed for inflammatory markers and lipoproteins. Systemic levels of C-reactive protein (CRP), interleukin-6 (IL-6), and serum amyloid A (SAA) in the aorta amounted to 3.0 mg/L, 5.0 ng/L, and 22.1 mg/L, respectively (interquartile ranges [IQRs], 1.1 to 7.4 mg/L, 5.0 to 6.5 ng/L, and 13.9 to 27.0 mg/L, respectively). In blood surrounding ruptured plaques, local levels of IL-6 (8.9 ng/L; IQR, 5.0 to 16.9 ng/L) and SAA (24.3 mg/L; IQR, 16.3 to 44.0 mg/L) were significantly higher, whereas CRP levels (2.5 mg/L; IQR, 0.9 to 7.7 mg/L) were decreased compared with the aorta (all P<0.0001). The coronary levels of IL-6 determined in vivo showed biological activity in vitro. Harvested thrombus contained CD68-positive monocytes expressing IL-6 and showed extracellularly and intracellularly positive staining for SAA, whereas CRP was found exclusively in the cytoplasm of phagocyting white blood cells. Conclusions—Coronary levels of IL-6 and SAA at the site of plaque rupture were increased relative to the systemic circulation, indicating local production of biologically active inflammatory mediators. In contrast, CRP was locally decreased, at least in part by uptake by the phagocyting cells, suggesting a systemic origin of the protein.

Tetrahydrobiopterin improves endothelial function in patients with coronary artery disease.

Tetrahydrobiopterin (BH4) is an essential cofactor for nitric oxide synthase (NOS) and a scavenger of oxygen-derived free radicals. Decreased availability of BH4 leads, under in vitro conditions, to reduced nitric oxide (NO) production and increased superoxide formation. We studied the effect of exogenous BH4 on endothelial function of angiographically normal vessel segments in patients with coronary artery disease. Nineteen patients with coronary artery disease underwent quantitative coronary angiography with simultaneous coronary flow velocity measurements (Cardiometrics FloWire). Data were obtained in angiographically normal segments of the left coronary artery at baseline, after intracoronary (i.c.) administration of acetylcholine (Ach; 10(-4) M), after infusion of BH4 (10(-2) M), and after co-infusion of ACh and BH4. At the end of the study, 300 microg nitroglycerin (NTG) i.c. was administered to obtain maximal vasodilation. At each step, flow velocity was determined before and after 18 microg adenosine i.c. to assess coronary flow velocity reserve. In 15 patients, ACh induced coronary vasoconstriction of -18 +/- 3% (endothelial dysfunction; p < 0.0001 vs. baseline), and in four patients, vasodilation of +39 +/- 20%. In the 15 patients with endothelial dysfunction, BH4 alone did not influence vessel area but prevented vasoconstriction to ACh (+2 +/- 3%, NS, vs. baseline). Correspondingly, calculated volume flow showed the highest value after co-infusion of ACh and BH4. Coronary flow velocity reserve was comparable during the various infusion steps. BH4 prevents ACh-induced vasoconstriction of angiographically normal vessels in patients with coronary artery disease. Thus substitution of this cofactor of NOS may represent a new approach for the treatment of endothelial dysfunction.

Cellular actors, Toll-like receptors, and local cytokine profile in acute coronary syndromes

AIMS Inflammation plays a key role in acute coronary syndromes (ACS). Toll-like receptors (TLR) on leucocytes mediate inflammation and immune responses. We characterized leucocytes and TLR expression within coronary thrombi and compared cytokine levels from the site of coronary occlusion with aortic blood (AB) in ACS patients. METHODS AND RESULTS In 18 ACS patients, thrombi were collected by aspiration during primary percutaneous coronary intervention. Thrombi and AB from these patients as well as AB from 10 age-matched controls without coronary artery disease were assessed by FACS analysis for cellular distribution and TLR expression. For further discrimination of ACS specificity, seven non-coronary intravascular thrombi and eight thrombi generated in vitro were analysed. In 17 additional patients, cytokine levels were determined in blood samples from the site of coronary occlusion under distal occlusion and compared with AB. In coronary thrombi from ACS, the percentage of monocytes related to the total leucocyte count was greater than in AB (47 vs. 20%, P = 0.0002). In thrombi, TLR-4 and TLR-2 were overexpressed on CD14-labelled monocytes, and TLR-2 was increased on CD66b-labelled granulocytes, in comparison with leucocytes in AB. In contrast, in vitro and non-coronary thrombi exhibited no overexpression of TLR-4. Local blood samples taken under distal occlusion revealed elevated concentrations of chemokines (IL-8, MCP-1, eotaxin, MIP-1alpha, and IP-10) and cytokines (IL-1ra, IL-6, IL-7, IL-12, IL-17, IFN-alpha, and granulocyte-macrophage colony-stimulating factor) regulating both innate and adaptive immunity (all P < 0.05). CONCLUSION In ACS patients, monocytes accumulate within thrombi and specifically overexpress TLR-4. Together with the local expression patterns of chemokines and cytokines, the increase of TLR-4 reflects a concerted activation of this inflammatory pathway at the site of coronary occlusion in ACS.

Clinical and angiographic outcome of patients with mild coronary lesions treated with balloon angioplasty or coronary stenting. Implications for mechanical plaque sealing

AIMS To investigate the clinical and angiographic outcome of patients with mild coronary lesions treated with balloon angioplasty or coronary stenting (coronary plaque sealing, i.e. dilatation of angiographically non-significant lesions) compared to moderate and severe stenoses. METHODS AND RESULTS Patients with chronic stable angina and a single de novo lesion in a native coronary vessel scheduled to undergo percutaneous coronary intervention (PCI) were selected from 14 different studies. Off-line analysis of angiographic outcomes was assessed in all patients using identical and standardised methods of data acquisition, analysis and definitions. Clinical endpoints were adjudicated by independent clinical events committees. All quantitative coronary angiographic (QCA) analyses were performed in the same core laboratory. Stenosis severity prior to PCI was categorised into three groups: <50% diameter stenosis (DS), 50-99%DS and >99%DS pre. A total of 3812 patients were included in this study; 1484 patients (39%) were successfully treated with balloon angioplasty (BA) only and stented angioplasty was performed in 2328 patients (61%).One-year mortality and rate of non-fatal myocardial infarction (MI) (Kaplan-Meier) did not differ between BA and stented angioplasty for any of the stenosis severity categories. Following BA, the combined event rate (death and non-fatal MI) was 4.8, 4.6 and 0% in the <50, 50-99 and >99%DS categories, respectively. Following stented angioplasty, the combined event rate was 3.1, 4.4 and 4.8% in the same categories. The need for repeat revascularisation corrected for stenosis severity in the Cox proportional-hazards regression model was reduced by 20% after stented angioplasty (hazard ratio (HR) 0.80, 95%CI 0.69-0.93). CONCLUSION The concept of plaque sealing is appealing from the theoretical point of view. However, with current technology, plaque sealing cannot prevent death and future non-fatal MIs in the long-term because 1-year event rates after PCI of non-significant stenoses remain unacceptably elevated when compared with the estimated 1-year probability of a non-fatal MI in lesions with a <50%DS. Moreover, major adverse cardiac events at 1-year after PCI are not directly related to the degree of pre-procedural stenosis severity.

The additional value of patient-reported health status in predicting 1-year mortality after invasive coronary procedures: a report from the Euro Heart Survey on Coronary Revascularisation

Objective: Self-perceived health status may be helpful in identifying patients at high risk for adverse outcomes. The Euro Heart Survey on Coronary Revascularization (EHS-CR) provided an opportunity to explore whether impaired health status was a predictor of 1-year mortality in patients with coronary artery disease (CAD) undergoing angiographic procedures. Methods: Data from the EHS-CR that included 5619 patients from 31 member countries of the European Society of Cardiology were used. Inclusion criteria for the current study were completion of a self-report measure of health status, the EuroQol Questionnaire (EQ-5D) at discharge and information on 1-year follow-up, resulting in a study population of 3786 patients. Results: The 1-year mortality was 3.2% (n = 120). Survivors reported fewer problems on the five dimensions of the EQ-5D as compared with non-survivors. A broad range of potential confounders were adjusted for, which reached a p<0.10 in the unadjusted analyses. In the adjusted analyses, problems with self-care (OR 3.45; 95% CI 2.14 to 5.59) and a low rating (⩽60) on health status (OR 2.41; 95% CI 1.47 to 3.94) were the most powerful independent predictors of mortality, among the 22 clinical variables included in the analysis. Furthermore, patients who reported no problems on all five dimensions had significantly lower 1-year mortality rates (OR 0.47; 95% CI 0.28 to 0.81). Conclusions: This analysis shows that impaired health status is associated with a 2–3-fold increased risk of all-cause mortality in patients with CAD, independent of other conventional risk factors. These results highlight the importance of including patients’ subjective experience of their own health status in the evaluation strategy to optimise risk stratification and management in clinical practice.

Myeloid related proteins activate Toll-like receptor 4 in human acute coronary syndromes

INTRODUCTION We previously reported increased expression of TLR4 on monocytes in thrombi from patients with acute coronary syndromes (ACS). In mice, myeloid related protein (MRP) 8 and MRP14, cytoplasmic proteins of neutrophils and monocytes, activate Toll-like receptor (TLR) 4 during sepsis. In human ACS, we investigated now whether the pro-inflammatory action of MRPs occurs through TLR4 in monocytes derived from thrombi. METHODS Coronary thrombi and peripheral blood of 27 ACS patients were analyzed. CD14(+) monocytes were isolated and incubated with TLR2 ligand PM3SKA, TLR4 ligand lipopolysaccharide (LPS), MRP8, MRP14, or MRP8/14 heterocomplex. Anti-TLR4 antibodies (HTA125) were used to block TLR4 and polymyxin B (PMB) was employed to inhibit endotoxins. Before and after stimulation, the release of TNFα was measured by ELISA and the expression of TLR4 on CD14(+) monocytes was determined by flow cytometry. Further, selected pathways of downstream signaling were analyzed. RESULTS MRP8 and MRP8/14 increased release of TNFα in cultures of CD14(+) monocytes, more in cells derived from thrombi compared with matched peripheral blood cells (p<0.001). LPS, MRP8, and MRP8/14, but much less PM3SKA and MRP14 alone, stimulated TNFα release, which can be inhibited by HTA125. MRP8/14 enhanced TLR4 expression on monocytes from thrombi (p<0.001), but not on monocytes from peripheral blood of the same patients. CONCLUSION In ACS, MRP8 and MRP8/14 complex are specific ligands of TLR4, which induce the release of TNFα and probably other pro-inflammatory agents from monocytes. This specific MRP8/14-dependent pathway with striking similarities to sepsis increasing expression of TLR4 in thrombi appears to be involved in the pathogenesis of coronary occlusion and may represent a novel therapeutic target in ACS.

Exercise-Induced Coronary Artery Vasodilation Is Not Impaired by Stent Placement

Background—Stenting has proved beneficial for treating threatened closure and reducing restenosis after balloon angioplasty. However, the implantation of a coronary metallic prosthesis has been related to impaired vasomotion distal to the stent as assessed by acetylcholine infusion. Thus, the purpose of the present study was to determine the vasomotion of stented coronary arteries and to assess its influence on the vasomotion of adjacent vessel segments during bicycle exercise. Methods and Results—Biplane quantitative coronary angiography was performed at rest and during bicycle exercise in 26 patients with coronary artery disease. Twelve patients had single vessel disease with stable angina pectoris (controls; group 1). Fourteen patients underwent coronary stenting for therapeutic reasons and were studied 10±3 months after the intervention (group 2). Minimal luminal area, stent area, and proximal and distal vessel areas were determined. In controls (group 1), vasoconstriction of the stenotic artery (− 29±4%;P <0.001) was observed during exercise, whereas the normal segment showed vasodilation (15±4%;P <0.05). In group 2, vasomotion of the stented segment was eliminated (0±1%), whereas the proximal and distal segments showed exercise-induced vasodilation (8±2% and 11±3%, respectively;P <0.005), which was not different from control segments (10±2%). Sublingual nitroglycerin was associated with maximal vasodilation of the proximal and distal vessel segments (30±8% and 38±13%, respectively;P <0.005). Conclusions—In contrast to the vasoconstriction of vessels in control patients, normal vasodilation of proximal and distal segments occurred during the physiological stress of exercise in patients with coronary stent placement. As expected, vasomotion was abolished in the stented region.

Expression of the aging gene p66Shc is increased in peripheral blood monocytes of patients with acute coronary syndrome but not with stable coronary artery disease.

OBJECTIVE The interplay between oxidative stress and inflammation is crucial in the pathogenesis of atherosclerosis. The adaptor protein p66Shc is implicated in atherogenesis and oxidative stress related responses in animal models of diseases. However, its role in humans remains to be defined. In this study, we hypothesized that expression of p66Shc increases in peripheral blood monocytes of patients affected by acute coronary syndromes (ACS). METHODS Male subjects aged 59±4 (mean±SD) years admitted for cardiac catheterization were subdivided in three groups: (a) no local stenosis for the control group, (b) at least one stenosis ≥75% in either left, circumflex or right coronary artery for the coronary artery disease (CAD) group or (c) ST-elevation/non-ST-elevation myocardial infarction for the ACS group. Monocytes were isolated from whole blood and p66Shc RNA levels were determined by quantitative real time PCR. RESULTS p66Shc RNA levels were increased in ACS patients as compared to CAD (p=0.007) and controls (p=0.0249). Furthermore, malondialdehyde (MDA) and C-reactive protein (CRP) were increased in plasma of ACS patients. Levels of MDA correlated positively to p66Shc (r=0.376, p=0.01). Our data demonstrate increased p66Shc levels in monocytes of ACS but not CAD patients. CONCLUSION This study suggests an involvement of p66Shc in the transition of a stable CAD to an ACS patient. p66Shc was associated with states of increased oxidative stress. Further work is needed to understand whether p66Shc may represent a possible pharmacological target or whether it represents an interesting novel biomarker.

Early and Late Mortality in Patients Undergoing Transcatheter Aortic Valve Implantation: Comparison of the Novel EuroScore II with Established Risk Scores

Objectives: In the evaluation of patients considered for transcatheter aortic valve implantation (TAVI), the EuroScore II might be superior to established risk scores. Methods: We assessed the performance of the EuroScore II in predicting mortality in a cohort of 350 TAVI patients. Results: The EuroScore II and the logistic EuroScore were higher in nonsurvivors compared to survivors at 30 days (12.6 ± 1.8 vs. 7.5 ± 0.3%, p < 0.001 for EuroScore II, and 27.7 ± 2.8 vs. 22.1 ± 0.8%, p = 0.04 for logistic EuroScore), while the STS-PROM score did not differ (7.3 ± 0.8 vs. 6.4 ± 0.3%, p = 0.09). The area under the curve (AUC) was 0.70 for the EuroScore II, 0.61 for the logistic EuroScore and 0.59 for the STS-PROM score for predicting 30-day mortality. Based on the estimated 30-day mortality risk, 3 risk groups were identified, a low-risk (EuroScore II ≤4%, 30-day mortality 1.2%), an intermediate-risk (EuroScore II between 4% and 9%, 30-day mortality 8.6%) and a high-risk group (EuroScore II >9%, 30-day mortality, 17.1%; p = 0.03). Regarding cumulative mortality, the AUC was 0.67 for the EuroScore II, 0.62 for the logistic EuroScore and 0.55 for the STS-PROM score for predicting mortality at total follow-up. Conclusions: In this patient cohort, the EuroScore II performed best in predicting short- and long-term mortality.