Association between complex coronary artery stenosis and unstable angina and the extent of plaque inflammation

Topography of immune cell infiltration in different stages of coronary atherosclerosis revealed by multiplex immunohistochemistry

Background

Aim of this study was to investigate immune cells and subsets in different stages of human coronary artery disease with a novel multiplex immunohistochemistry (mIHC) technique.

Methods

Human left anterior descending coronary artery specimens were analyzed: eccentric intimal thickening (N = 11), pathological intimal thickening (N = 10), fibroatheroma (N = 9), and fibrous plaque (N = 9). Eccentric intimal thickening was considered normal, and pathological intimal thickening, fibroatheroma, and fibrous plaque were considered diseased coronary arteries. Two mIHC panels, consisting of six and five primary antibodies, autofluoresence, and DAPI, were used to detect adaptive and innate immune cells. Via semi-automated analysis, (sub)types of immune cells in whole plaques and specific plaque regions were quantified.

Results

Increased numbers of CD3⁺ T cells (P < 0.001), CD20⁺ B cells (P = 0.013), CD68⁺ macrophages (P = 0.003), CD15⁺ neutrophils (P = 0.017), and CD31⁺ endothelial cells (P = 0.024) were identified in intimas of diseased coronary arteries compared to normal. Subset analyses of T cells and macrophages showed that diseased coronary arteries contained an abundance of CD3⁺CD8^- non-cytotoxic T cells and CD68⁺CD206^- non-M2-like macrophages. Proportions of CD3⁺CD45RO⁺ memory T cells were similar to normal coronary arteries. Among pathological intimal thickening, fibroatheroma, and fibrous plaque, all immune cell numbers and subsets were similar.

Conclusions

The type of immune response does not differ substantially between different stages of plaque development and may provide context for mechanistic research into immune cell function in atherosclerosis. We provide the first comprehensive map of immune cell subtypes across plaque types in coronary arteries demonstrating the potential of mIHC for vascular research.

The Association Between High-Sensitivity C-Reactive Protein/Albumin Ratio and Cardiovascular Prognosis in Patients Undergoing Percutaneous Coronary Intervention

Limited studies have focused on the impact of high-sensitivity C-reactive protein (hsCRP) to albumin ratio (CAR) on cardiovascular outcomes in patients undergoing percutaneous coronary intervention (PCI). Hence, the present study evaluates the association between CAR and cardiovascular outcomes in patients undergoing drug-eluting stent (DES) implantation. We consecutively enrolled 9375 CHD patients undergoing DES implantation. All patients were divided into 3 groups according to their CAR: tertile 1 (CAR ≤.02, n=3125), tertile 2 (.02<CAR≤.06, n = 3125), and tertile 3 (CAR >.06, n = 3125). The primary endpoint was major adverse cardiovascular and cerebrovascular events (MACCE). Kaplan-Meier analysis indicated that the incidences of MACCE and MI increased with high tertiles of the CAR (MACCE: 8.7 vs 10.5 vs 12.3%, log-rank P < .001; MI: 3.3 vs 4.0 vs 4.7%, long-rank P = .015). Cox regression analysis suggested that CAR was an independent risk factors for MACCE (HR per standard deviation (SD) increase: 1.07, 95% CI, 1.01-1.14, P = .024), and MI (HR per SD increase: 1.11, 95% CI, 1.01-1.22, P = .028). In conclusion, the CAR is an independent predictor of MACCE and MI in CHD patients.

The comparison of IL-17 levels in patients with unstable angina before and after medical treatment

BACKGROUND

Interleukin (IL)-17 plays a central role in orchestrating the cytokine cascade and accelerates atherosclerosis and plaque vulnerability in animal models. However, epidemiological data evaluating the role of IL-17 levels in unstable angina are lacking. The aim of our study is to evaluate and compare the IL-17 levels in unstable angina (UA) cases before and after treatment.

METHODS

This cross-sectional study was performed from July to October 2018 in Ali Iben-abitaleb heart center, Zahedan, Iran. 48 patients with UA in the age range of below 50 years entered the study. All demographic, past medical history, physical examination, electrocardiogram (EKG or ECG), and transthoracic echocardiogram (TTE) data were collected. Serum level of IL-17 was measured using enzyme-linked immunosorbent assay (ELISA) method. In all the tests, P< 0.05 was considered as statistically significant. All data analyses were performed using the SPSS 13.0 software (SPSS Inc., Chicago, Illinois, USA).

RESULTS

In this study, 48 UA patients, including 34 women and 16 men with a mean age of 56.60 years were included in the study. The mean serum level of interleukin 17 after treatment (65.13 ± 53.29 pg/dl) was significantly lower than Its level before treatment (94.89 ± 51.25 pg/dL) (P< 0/05).

CONCLUSION

Our findings point towards a role of inflammation in the form of increased activity of IL-17 in UA patients and thus suggest that IL-17-driven inflammation may play a role in the promotion of clinical instability in patients with coronary artery disease.

High Plasma Levels of Legumain in Patients with Complex Coronary Lesions

Aim: The degradation of the vascular extracellular matrix is important for atherosclerosis. The cysteine protease legumain was shown to be upregulated in atherosclerotic plaques, especially unstable plaques. However, no study has reported blood legumain levels in patients with coronary artery disease (CAD).

Methods: We investigated plasma legumain and C-reactive protein (CRP) levels in 372 patients undergoing elective coronary angiography.

Results: CAD was found in 225 patients. Compared with patients without CAD, those with CAD had higher CRP levels (median 0.60 [0.32, 1.53] vs. 0.46 [0.22, 0.89] mg/L, P < 0.001), but no difference was found in legumain levels between patients with and without CAD (median 5.08 [3.87, 6.82] vs. 4.99 [3.84, 6.88] ng/mL). A stepwise increase in CRP was found depending on the number of > 50% stenotic vessels: 0.55 mg/L in 1-vessel, 0.71 mg/L in 2-vessel, and 0.86 mg/L in 3-vessel diseases (P < 0.001). However, legumain did not differ among 1-, 2-, and 3-vessel diseases (5.20, 4.93, and 5.01 ng/mL, respectively). Of 225 patients with CAD, 40 (18%) had complex lesions. No difference was found in CRP levels between patients with CAD with and without complex lesions (0.60 [0.34, 1.53] vs. 0.60 [0.32, 1.51] mg/L). Notably, legumain levels were higher in patients with CAD with complex lesions than without such lesions (6.05 [4.64, 8.64] vs. 4.93 [3.76, 6.52] ng/mL, P < 0.01). In multivariate analysis, legumain levels were not a factor for CAD, but were a factor for complex lesions. The odds ratio for complex lesions was 2.45 (95% CI = 1.26–4.79) for legumain > 5.5 ng/mL.

Conclusion: Plasma legumain levels were associated with the presence of complex coronary lesions.

Circulating Oxidized Low-Density Lipoprotein is a Strong Risk Factor for the Early Stage of Coronary Heart Disease

This study aimed to detect the circulating oxidized low-density lipoprotein (ox-LDL) levels of controls and patients with stable angina pectoris (SAP), unstable angina pectoris (UAP), and acute myocardial infarction (AMI) and also to investigate the correlation with the severity of coronary heart disease (CHD). Plasma levels of circulating ox-LDL-4E6, malondialdehyde (MDA), high-sensitivity C-reactive protein (hs-CRP), total cholesterol, high-density lipoprotein cholesterol, LDL cholesterol, apoprotein A, apoprotein B, and lipoprotein (a) (Lp(a)) were measured in 99 participants who underwent coronary angiography. The plasma ox-LDL level was significantly higher in patients with CHD than in controls (P = 0.000). However, it was lower in the UAP and AMI groups than in the SAP group (P = 0.000). The lipid peroxide level (MDA) showed a significant difference among all groups (P = 0.000). It increased significantly in patients with CHD. The Lp(a) and hs-CRP levels were significantly higher in patients with CHD (P = 0.000 and 0.000, respectively). No difference in Lp(a) was found among the SAP, UAP, and AMI groups (P = 0.296). In patients with CHD, the plasma ox-LDL correlated negatively with hs-CRP (P = 0.011), and serum MDA correlated positively with hs-CRP (P = 0.004). The plasma ox-LDL could be used as a strong risk factor for the early stage but not the advanced stage of CHD. Hs-CRP may bound and transfer ox-LDL to macrophages. © 2018 IUBMB Life, 71(1):277-282, 2019.

Resting myocardial blood flow quantification using contrast-enhanced magnetic resonance imaging in the presence of stenosis: A computational fluid dynamics study

PURPOSE

The extent to which atherosclerotic plaques affect contrast agent (CA) transport in the coronary arteries and, hence, quantification of myocardial blood flow (MBF) using magnetic resonance imaging (MRI) is unclear. The purpose of this work was to evaluate the influence of plaque induced stenosis both on CA transport and on the accuracy of MBF quantification.

METHODS

Computational fluid dynamics simulations in a high-detailed realistic vascular model were employed to investigate CA bolus transport in the coronary arteries. The impact of atherosclerosis was analyzed by inserting various medium- to high-grade stenoses in the vascular model. The influence of stenosis morphology was examined by varying the stenosis shapes but keeping the area reduction constant. Errors due to CA bolus transport were analyzed using the tracer-kinetic model MMID4.

RESULTS

Dispersion of the CA bolus was found in all models and for all outlets, but with a varying magnitude. The impact of stenosis was complex: while high-grade stenoses amplified dispersion, mild stenoses reduced the effect. Morphology was found to have a marked influence on dispersion for a small number of outlets in the post-stenotic region. Despite this marked influence on the concentration-time curves, MBF errors were less affected by stenosis. In total, MBF was underestimated by -7.9% to -44.9%.

CONCLUSIONS

The presented results reveal that local hemodynamics in the coronary vasculature appears to have a direct impact on CA bolus dispersion. Inclusion of atherosclerotic plaques resulted in a complex alteration of this effect, with both degree of area reduction and stenosis morphology affecting the amount of dispersion. This strong influence of vascular transport effects impairs the accuracy of MRI-based MBF quantification techniques and, potentially, other bolus-based perfusion measurement techniques like computed tomography perfusion imaging.

The level of serum bilirubin associated with coronary lesion types in patients with coronary artery disease

BACKGROUND

Serum bilirubin has been proven to be associated with coronary artery disease (CAD). However, how serum bilirubin is related to the complexity of coronary artery lesions is still unknown.

METHODS AND RESULTS

One thousand two hundred and sixty patients (men 775, 61.5%, mean age, 59.3  ±  8.2 years) diagnosed with unstable angina were enrolled in the study. Patients were categorized into three major groups and group III was further divided into four subgroups according to the guidelines of AHA/ACC 1993 described in the Methods section. The total serum bilirubin levels showed significant differences among the three major groups (group I vs. group II, 14.8 ± 5.8 vs. 13.7 ± 4.7 μmol/l, P=0.017; group I vs. group III, 14.8 ± 5.8 vs. 12.6 ±  4.4 μmol/l, P<0.001; group II vs. group III, 13.7 ± 4.7 vs. 12.6 ± 4.4 μmol/l, P=0.009). The difference was further seen among the subgroups. Logistic regression analysis demonstrated that age, male sex, histories of hypertension and diabetes, and total serum bilirubin were independent risk factors for CAD. However, in the subgroups, only age, male sex, history of hypertension and total serum bilirubin were associated with CAD. Total serum bilirubin showed the strongest relationship (odds ratio=0.95, 95% confidence interval 0.91-0.98, P=0.001).

CONCLUSION

Total serum bilirubin level is an independent risk factor for CAD. It has a strong relationship with coronary artery lesion types.

Localization to atherosclerotic plaque and biodistribution of biochemically derivatized superparamagnetic iron oxide nanoparticles (SPIONs) contrast particles for magnetic resonance imaging (MRI)

Annexin V recognizes apoptotic cells by specific molecular interaction with phosphatidyl serine, a lipid that is normally sequestered in the inner leaflet of the cell membrane, but is translocated to the outer leaflet in apoptotic cells, such as foam cells of atherosclerotic plaque. Annexin V could potentially deliver carried materials (such as superparamagnetic contrast agents for magnetic resonance imaging) to sites containing apoptotic cells, such as high grade atherosclerotic lesions, so we administered biochemically-derivatized (annexin V) superparmagnetic iron oxide particles (SPIONs) parenterally to two related rabbit models of human atherosclerosis. We observe development of negative magnetic resonance imaging (MRI) contrast in atheromatous lesions and but not in healthy artery. Vascular targeting by annexin V SPIONs is atheroma-specific (i.e., does not occur in healthy control rabbits) and requires active annexin V decorating the SPION surface. Targeted SPIONs produce negative contrast at doses that are 2,000-fold lower than reported for non-specific atheroma uptake of untargeted superparamagnetic nanoparticles in plaque in the same animal model. Occlusive and mural plaques are differentiable. While most of the dose accumulates in liver, spleen, kidneys and bladder, annexin V SPIONs also partition rapidly and deeply into early apoptotic foamy macrophages in plaque. Contrast in plaque decays within 2 months, allowing MRI images to be replicated with a subsequent, identical dose of annexin V SPIONs. Thus, biologically targeted superparamagnetic contrast agents can contribute to non-invasive evaluation of cardiovascular lesions by simultaneously extracting morphological and biochemical data from them.

Predictors and prognosis for complex coronary lesions in patients with acute myocardial infarction: data from RICO survey

BACKGROUND

We aimed to investigate the determinants and outcomes of multiple complex lesions (MCLs) on coronary angiography in patients with an acute myocardial infarction.

METHODS

One thousand one hundred fifty-two consecutive nonselected myocardial infarction patients who underwent coronary angiography within 24 hours after admission were analyzed. A complex lesion was defined by the presence of thrombus, ulceration, irregular plaque, and flow impairment. Patients with < or = 1 complex lesion were considered with single complex lesion (SCL), and patients with > 1 complex lesions with MCLs.

RESULTS

Multiple complex lesions were identified in 360 patients (31%). Patients from the MCL group were older and had a higher rate of cardiovascular risk factors but were less likely to be smokers when compared with the SCL group. Patients with MCLs were more likely to have altered left ventricular ejection fraction and multivessel disease and showed a trend toward an increased median time delay to revascularization (360 vs 285 minutes; P = .070). Moreover, the C-reactive protein (CRP) plasma levels increased with the number of CLs. By multivariate analysis, multivessel disease and CRP level were associated with the presence of MCLs. When compared with the SCL group, patients with MCLs had a higher risk of inhospital cardiogenic shock (18% vs 11%; P = .005) and 30-day mortality (11% vs 6%; P = .002). At 1-year follow-up, the presence of MCLs was an independent predictive factor of death.

CONCLUSIONS

This study shows that the presence of MCLs is associated with worse outcomes and that risk factors such as CRP are able to identify patients at a high risk for MCLs.

Association of plasma leptin levels and complexity of the culprit lesion in patients with unstable angina

BACKGROUND

Angiographically visible complex lesions which are associated with plaque vulnerability have been shown to correlate strongly with clinical severity of unstable angina (UA). By activating different immune/inflammatory cells or directly acting on the vessel wall leptin has been shown to play a potential role in the development of acute coronary syndrome. However, the relationship between leptin and simple or complex lesion morphology in UA has not been investigated. Therefore, we designed this study to determine the association between plasma leptin level and simple or complex lesions in patients with UA and to see any correlation between leptin and other inflammatory markers in these patients.

METHODS

Plasma concentrations of leptin, interleukin (IL)-6, IL-10 and high-sensitivity C-Reactive Protein (hsCRP) were analyzed in 47 patients with UA. These patients were also angiographically studied and divided into two groups: simple lesion (n=18) and complex lesion (n=29) based on the coronary plaque morphology. We further compared them with 20 control subjects having no evidence of coronary artery diseases.

RESULTS

Plasma leptin concentrations were higher in patients having complex lesions compared to those having simple lesions as well as normal controls. Similarly IL-6 and hsCRP were also higher in complex lesion group compared to simple lesion group and controls, and leptin was positively correlated with IL-6 and hsCRP. Concentrations of IL-10 were lower in simple and complex lesion groups compared to the controls and leptin was negatively correlated with IL-10, but no significant difference between simple and complex lesions was found. Furthermore, leptin was found to be an independent predictor for the complex lesion morphology in UA patients.

CONCLUSION

These findings suggested that angiographically visible complex lesions are associated with increased concentrations of leptin, and thus leptin can be a useful biomarker for risk stratification in UA.

Elevated plasma levels of oxidized low-density lipoprotein relate to the presence of angiographically detected complex and thrombotic coronary artery lesion morphology in patients with unstable angina

BACKGROUND

Increased levels of oxidized low-density lipoprotein (ox-LDL) are related to plaque instability, so the aim of the present study was to investigate whether there is a relationship between angiographic coronary plaque morphology in patients with unstable angina pectoris (UAP) and the level of ox-LDL.

METHODS AND RESULTS

Plasma ox-LDL levels were measured in 149 patients with UAP and in 88 control subjects, using a highly sensitive enzyme-linked immunosorbent assay method. Angiographic morphology of the culprit lesion was classified as either simple or complex based on the Ambrose classification. Plasma ox-LDL levels in patients with Braunwald class III were significantly higher than in patients with class I (p<0.0001) or in control subjects (p<0.0001). In each of the 3 Braunwald classes, plasma ox-LDL levels in patients with a complex lesion were significantly higher than in patients with a simple lesion. Multivariate logistic regression analysis revealed that ox-LDL level and Braunwald class III were independent factors associated with angiographically detected complex lesions.

CONCLUSION

In each Braunwald class of UAP, elevated plasma levels of ox-LDL closely relate to the presence of angiographically detected complex and thrombotic lesion morphology.

Role of interleukin-17 and interleukin-17-induced cytokines interleukin-6 and interleukin-8 in unstable coronary artery disease

BACKGROUND

Atherosclerosis is a chronic inflammatory disease and interleukins are considered to play a key role in the chronic vascular inflammatory response that is typical of atherosclerosis. The serum levels of several of these cytokines have been found to positively correlate with coronary arterial disease and its sequelae.

AIM

The aim of our study was to evaluate the levels of a comparatively new cytokine IL-17, in patients with stable and unstable coronary artery disease in order to assess whether unstable coronary artery disease patients had higher IL-17 levels.

MATERIALS AND METHODS

We analyzed the concentrations of IL-17, IL-6, IL-8 and IL-10 using enzyme-linked immunosorbent assay and heat-sensitive C-reactive protein using latex particle-enhanced immunoturbidimetry in 58 consecutive unselected patients divided into three groups: stable angina (n=14), unstable angina (n=24) and acute myocardial infarction (n=20). We further compared them with 20 healthy controls. These 58 patients were also angiographically studied and divided into two groups: simple lesion (n=22) and complex lesion (n=36), on the basis of the coronary plaque morphology.

RESULTS

Our results show increased concentrations of the proinflammatory cytokines IL-17, IL-6, IL-8 and heat-sensitive C-reactive protein, and decreased concentration of IL-10 in plasma of unstable angina and acute myocardial infarction patients. Plasma concentration of IL-17 was also positively correlated with plasma concentrations of IL-6 and heat-sensitive C-reactive protein. Our findings further showed that IL-17 values were higher in patients having angiographically visible complex types of lesions but no difference was observed between complex and simple lesion morphology patients.

CONCLUSION

In conclusion, these findings point towards a role of inflammation in the form of increased activity of IL-17, IL-6 and IL-8 in patients of unstable angina and acute myocardial infarction and thus suggest that IL-17-driven inflammation may play a role in the promotion of clinical instability in patients with coronary artery disease.

Toll-like receptor 4 polymorphism is associated with coronary stenosis but not with the occurrence of acute or old myocardial infarctions

OBJECTIVE

Atherosclerosis is considered to be a chronic inflammatory disease. Toll-like receptor 4 (TLR-4), a key mediator in activating inflammatory cascade, has an A-to-G functional polymorphism that changes aspartic acid to glycine at position 299. TLR-4 is activated by, for example, lipopolysaccharides. The purpose of this study was to investigate the role of a common Asp299Gly polymorphism of the TLR-4 gene in atherosclerosis.

MATERIAL AND METHODS

The study comprised autopsy material from 657 men (the Helsinki Sudden Death Study; mean age 53, range 33-70 years).

RESULTS

Fewer G-allele carriers had 3-vessel coronary artery disease compared with AA homozygotes (OR 0.32; 95 % CI, 0.12-0.88, p = 0.027), and they also had a lower mean value for maximal coronary stenosis (p = 0.019). TLR-4 polymorphism was not significantly associated with the occurrence of acute or old myocardial infarction (MI).

CONCLUSIONS

The G allele of the TLR-4 gene, which is associated with a lower inflammation response, was associated with a lower risk of coronary stenosis but not with the occurrence of MI and hence is not a major factor in the development of coronary atherosclerosis.

Colocalisation of intraplaque C reactive protein, complement, oxidised low density lipoprotein, and macrophages in stable and unstable angina and acute myocardial infarction

BACKGROUND

C reactive protein (CRP), an important serum marker of atherosclerotic vascular disease, has recently been reported to be active inside human atherosclerotic plaques.

AIMS

To investigate the simultaneous presence of macrophages, CRP, membrane attack complex C5b-9 (MAC), and oxidised low density lipoprotein (oxLDL) in atherectomy specimens from patients with different coronary syndromes.

METHODS

In total, 54 patients with stable angina (SA; n = 21), unstable angina (UA; n = 15), and myocardial infarction (MI; n = 18) underwent directional coronary atherectomy for coronary lesions. Cryostat sections of atherosclerotic plaques were immunohistochemically stained with monoclonal antibodies: anti-CD68 (macrophages), anti-5G4 (CRP), aE11 (MAC), and 12E7 (oxLDL). Immunopositive areas were evaluated in relation to fibrous and neointima tissues, atheroma, and media. Quantitative analysis was performed using image cytometry with systematic random sampling (percentage immunopositive/total tissue area).

RESULTS

Macrophages, CRP, MAC, and oxLDL were simultaneously present in a higher proportion of fibrous tissue and atheroma of atherectomy specimens from patients with UA and MI compared with SA (p<0.05). Quantitative analysis showed significantly higher mean percentages of macrophages in plaques from patients with MI (44%) than UA (30%; p<0.01) and SA (20%; p<0.001). Significantly higher mean percentages of CRP were also seen in MI (25%) and UA (25%) compared with SA (12%; p<0.05).

CONCLUSIONS

The presence of CRP, complement, and oxLDL in a high proportion of plaque tissue from patients with unstable coronary artery disease implies that these surrogate markers have important proinflammatory effects inside atherosclerotic plaques. This may increase vulnerability to plaque rupture and thrombosis, with subsequent clinical sequelae.

Composition of coronary plaques obtained by directional atherectomy in stable angina: its relation to serum lipids and statin treatment

OBJECTIVES

The stability and inflammatory activity in atherosclerotic plaques may be modulated by lipids and lipoproteins as well as the pleiotropic effects of statins. The aim of this study was to analyse the effect of statin treatment as well as the relation of plasma lipids and lipoproteins to tissue composition in atherosclerotic plaques.

DESIGN

Patients with stable angina and coronary plaques suitable for directional coronary atherectomy (DCA) were randomized to atorvastatin (80 mg once daily) or placebo (29 randomized, 22 underwent DCA, 11/group). After an average treatment of 10 weeks, patients underwent DCA, tissue specimens were obtained, and the tissue composition was determined by immunohistochemistry.

RESULTS

Atorvastatin reduced the T-cell content, but did not change lipid, collagen, smooth muscle cell, or macrophage content. Plasma levels of apolipoprotein AI (apoAI) correlated positively with tissue collagen and inversely with metalloproteinase-9 and macrophage content. About half the specimens contained neutrophil granulocytes.

CONCLUSIONS

Short-term atorvastatin treatment tended to reduce the T-cell content of atherosclerotic plaques, indicating modulation of cell-mediated immunity. High plasma levels of apoAI correlated with increased collagen content and reduced inflammation, supporting the notion that plasma apoAI stabilizes atherosclerotic plaques. The significance of neutrophils in the lesions merits further study.

Effects of adrenergic agents on rat peritoneal macrophages activated in vitro by acetylated low-density lipoprotein

Macrophages interact with modified lipoproteins and alter their functional status. In this study, the effects of the adrenergic agents adrenaline, isoproterenol, and dobutamine on macrophages activated with acetylated low-density lipoprotein were tested. The aim of this investigation was to determine whether adrenergic agents influence biologically significant functions of these cells in an in vitro model of macrophage-lipoprotein acute interaction. Rat peritoneal macrophages were incubated with acetylated low-density lipoprotein for 16 h, with or without adrenergic agents. Hydrogen peroxide and nitric oxide production and acid phosphatase activities in the supernatant and cell lysate were assayed. Adrenaline and isoproterenol inhibited the production of hydrogen peroxide, stimulated the production of nitric oxide, and increased the extracellular activity of acid phosphatase in the lipoprotein-activated cells. Dobutamine increased the extracellular, but decreased the intracellular acid phosphatase activity. Adrenaline and dobutamine also produced changes in the cell size and nuclear morphology of the macrophages. Macrophages are activated in vitro by acetylated low-density lipoprotein, and their functions and morphology are modified under the influence of adrenergic agents. Certain effects could be attributed to changes in cyclic AMP levels.

Plasma levels of oxidized-low-density lipoproteins are higher in patients with unstable angina and correlated with angiographic coronary complex plaques

OBJECTIVES

To measure circulating levels of oxidized-low-density lipoproteins (ox-LDL) in patients with stable and unstable angina and controls, and to investigate their correlation with the extent of coronary artery disease (CAD) and the presence of complex plaques at coronary angiography.

METHODS AND RESULTS

Circulating ox-LDL were assessed, using ELISA, in patients with unstable angina (UA, n=26), stable angina (SA, n=29) and in controls (C, n=27). All patients underwent coronary angiography. The extent of CAD was evaluated using a quantitative score, while the presence of complex, vulnerable plaques was angiographically assessed. Ox-LDL were higher in UA patients than in SA patients and in C subjects, and in SA patients than in C subjects (C, 45.6+/-12.8 U/L; SA, 58.8+/-11.0 U/L; UA, 73.7+/-13.6 U/L; p<0.001). No correlation was found with the extent of atherosclerotic disease in the coronary tree. Patients with angiographic complex lesions showed significantly higher levels of ox-LDL (68.4+/-13.9 U/L versus 55.2+/-16.4 U/L, p<0.001). Multiple regression analysis showed that ox-LDL were independent predictors of the presence of complex plaques (p<0.023).

CONCLUSIONS

Ox-LDL levels are higher in unstable patients and correlate with the presence of angiographically documented complex plaques. Ox-LDL might be markers of destabilization of CAD.

T helper cell related interleukins and the angiographic morphology in unstable angina

Angiographically visible complex lesions, associated with disrupted plaques and intraluminal thrombus, are more common in unstable angina (UA). The aim of our study was to evaluate the relationship between the complex lesions and the T helper cells related Interleukins (IL). We analyzed the concentrations of IL-10, IL-12, IL-18 using ELISA and that of hsCRP using Latex particle enhanced Immunoturbidimetry in 50 patients of UA. Thirty-one of these patients had complex lesions and 19 had simple lesions as visible during coronary angiography. We further compared them with 30 control subjects having no evidence of coronary artery diseases. The levels of IL-12 in patients having complex lesions tended to be higher than in those having simple lesions and levels of IL-10 tended to be lower in the former than the latter, but the differences were not statistically significant. The patients with complex lesions showed significantly higher concentrations of IL-18 as compared to those having simple lesions. Furthermore, IL-18 was found to be independent predictor for the complex lesion morphology in UA patients. These findings suggest that disrupted plaques and intraluminal thrombus, angiographically visible as complex lesions are associated with increased concentrations of T helper 1 cell related interleukins, mainly IL-18, and IL-18 being a possible bio-marker for risk stratification in UA.

What causes acute coronary syndromes? Applying Koch's postulates

The term "acute coronary syndromes" (ACS) is used to describe a heterogeneous spectrum of clinical conditions. This includes myocardial infarction, non-ST-elevation myocardial infarction, and unstable angina. These conditions are linked by a similar constellation of signs and symptoms but not necessarily by a common pathophysiology. They are syndromes. Several different hypotheses exist that have attempted to explain the pathological mechanisms that are involved in these conditions, however, it is not clear whether ACS are caused by variations of a single disease process or by several disease processes. The contribution of both vessel wall- and blood-related factors in the pathogenesis of acute coronary syndromes is herein discussed with the guidance of Koch's postulates.

Predictive value of associations between carotid and coronary artery disease in patients with acute coronary syndromes

The present study evaluated the association among sonographic characteristics of carotid plaques, angiographic morphology of coronary lesions, and outcomes of patients who had acute coronary syndromes. In treatment-stratified Cox's proportional hazards regression analysis, hard carotid plaques and coronary lesions of complex morphology were found to be independent predictors of future cardiac events.

Emergence of dendritic cells in rupture-prone regions of vulnerable carotid plaques

Dendritic cells (DC), which are critically involved in various immunological disorders, were detected in atherosclerotic plaques in 1995. Since DC might be related to the immunological processes in atherosclerosis (AS), we analyzed the emergence of DC and other inflammatory cells in different stages of AS. Serial cross-sections of 44 carotid specimens were immunohistochemically analyzed for the presence of DC, T cells, macrophages, and HLA-DR. Atherosclerotic specimens were histologically defined as initial lesions, advanced stable, or vulnerable plaques. In initial lesions significantly lower DC numbers were detected than in advanced plaques (P < 0.001). For advanced plaques, DC numbers were significantly higher in vulnerable than in stable plaques (P = 0.005). In contrast to initial lesions, approximately 70% of DC in advanced plaques exhibited a mature phenotype (CD83+, DC-LAMP+), indicating a functional activity of DC. In plaques of patients with acute ischemic symptoms DC numbers were markedly elevated (P = 0.03), whereas significantly lower DC numbers and more often a stable plaque morphology were detected in statin-treated patients (P = 0.02). DC clusters with a strong HLA-DR expression and frequent DC-T cell contacts were located particularly in the rupture-prone plaque regions and at complications. The results of the present study indicate that DC might contribute to plaque destabilization through an activation of T cells.