Does low-density lipoprotein cholesterol induce inflammation? If so, does it matter? Current insights and future perspectives for novel therapies.

BACKGROUND: Dyslipidemia and inflammation are closely interrelated contributors in the pathogenesis of atherosclerosis. Disorders of lipid metabolism initiate an inflammatory and immune-mediated response in atherosclerosis, while low-density lipoprotein cholesterol (LDL-C) lowering has possible pleiotropic anti-inflammatory effects that extend beyond lipid lowering. MAIN TEXT: Activation of the immune system/inflammasome destabilizes the plaque, which makes it vulnerable to rupture, resulting in major adverse cardiac events (MACE). The activated immune system potentially accelerates atherosclerosis, and atherosclerosis activates the immune system, creating a vicious circle. LDL-C enhances inflammation, which can be measured through multiple parameters like high-sensitivity C-reactive protein (hsCRP). However, multiple studies have shown that CRP is a marker of residual risk and not, itself, a causal factor. Recently, anti-inflammatory therapy has been shown to decelerate atherosclerosis, resulting in fewer MACE. Nevertheless, an important side effect of anti-inflammatory therapy is the potential for increased infection risk, stressing the importance of only targeting patients with high residual inflammatory risk. Multiple (auto-)inflammatory diseases are potentially related to/influenced by LDL-C through inflammasome activation. CONCLUSIONS: Research suggests that LDL-C induces inflammation; inflammation is of proven importance in atherosclerotic disease progression; anti-inflammatory therapies yield promise in lowering (cardiovascular) disease risk, especially in selected patients with high (remaining) inflammatory risk; and intriguing new anti-inflammatory developments, for example, in nucleotide-binding leucine-rich repeat-containing pyrine receptor inflammasome targeting, are currently underway, including novel pathway interventions such as immune cell targeting and epigenetic interference. Long-term safety should be carefully monitored for these new strategies and cost-effectiveness carefully evaluated.

Influence of carbon source on cell size and production of anti LDL (-) single-chain variable fragment by a recombinant Pichia pastoris strain.

The aim of this work was to study the effect of the carbon source (glycerol, sucrose, glucose or a sucrose/glucose mixture) on the production of the anti LDL (-) single-chain variable fragment (scFv) by the recombinant Pichia pastoris SMD 1168 strain as well as on the cell size. The use of glucose as a carbon source in the growth phase led to a remarkable increase in cell size compared with glycerol, while the smallest cells were obtained with sucrose likely due to the occurrence of an energetic stress. The scFv concentration seemed to be related to cell number rather than to cell concentration, which in its turn showed no significant dependence on the carbon source. Yeast cells grown on sucrose had a mean diameter (0.736 ± 0.097 µm) about 35% shorter than those grown on glucose and allowed for the highest final concentration of the scFv antibody fragment (93.7 ± 0.2 mg/L). These results demonstrate that sucrose is the best carbon source for the expression of such an antibody fragment by the recombinant P. pastoris strain, which may be very useful for the diagnostic analysis of the so-called "bad cholesterol".

The Therapeutic Potential of Anti-Inflammatory Exerkines in the Treatment of Atherosclerosis.

Although many cardiovascular (CVD) medications, such as antithrombotics, statins, and antihypertensives, have been identified to treat atherosclerosis, at most, many of these therapeutic agents only delay its progression. A growing body of evidence suggests physical exercise could be implemented as a non-pharmacologic treatment due to its pro-metabolic, multisystemic, and anti-inflammatory benefits. Specifically, it has been discovered that certain anti-inflammatory peptides, metabolites, and RNA species (collectively termed "exerkines") are released in response to exercise that could facilitate these benefits and could serve as potential therapeutic targets for atherosclerosis. However, much of the relationship between exercise and these exerkines remains unanswered, and there are several challenges in the discovery and validation of these exerkines. This review primarily highlights major anti-inflammatory exerkines that could serve as potential therapeutic targets for atherosclerosis. To provide some context and comparison for the therapeutic potential of exerkines, the anti-inflammatory, multisystemic benefits of exercise, the basic mechanisms of atherosclerosis, and the limited efficacies of current anti-inflammatory therapeutics for atherosclerosis are briefly summarized. Finally, key challenges and future directions for exploiting these exerkines in the treatment of atherosclerosis are discussed.

Heritability of Biomarkers of Oxidized Lipoproteins: Twin Pair Study.

OBJECTIVE: To determine whether biomarkers of oxidized lipoproteins are genetically determined. Lipoprotein(a) (Lp[a]) is a heritable risk factor and carrier of oxidized phospholipids (OxPL). APPROACH AND RESULTS: We measured oxidized phospholipids on apolipoprotein B-containing lipoproteins (OxPL-apoB), Lp(a), IgG, and IgM autoantibodies to malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes in 386 monozygotic and dizygotic twins to estimate trait heritability (h(2)) and determine specific genetic effects among traits. A genome-wide linkage study followed by genetic association was performed. The h(2) (scale: 0-1) for Lp(a) was 0.91±0.01 and for OxPL-apoB 0.87±0.02, which were higher than physiological, inflammatory, or lipid traits. h(2) of IgM malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes were 0.69±0.04, 0.67±0.05, and 0.80±0.03, respectively, and for IgG malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes 0.62±0.05, 0.52±0.06, and 0.53±0.06, respectively. There was an inverse correlation between the major apo(a) isoform and OxPL-apoB (R=-0.49; P<0.001) and Lp(a) (R=-0.48; P<0.001) and OxPL-apoB was modestly correlated with Lp(a) (ρ=0.57; P<0.0001). The correlation in major apo(a) isoform size was concordant (R=1.0; P<0.001) among monozygotic twins but not dizygotic twins (R=0.40; P=0.055). Lp(a) and OxPL-apoB shared genetic codetermination (genetic covariance, ρG=0.774±0.032; P=1.09×10(-38)), although not environmental determination (environmental covariance, ρE=0.081±0.15; P=0.15). In contrast, Lp(a) shared environmental but not genetic codetermination with autoantibodies to malondialdehyde-modified low-density lipoprotein and copper oxidized low-density lipoprotein, and apoB-immune complexes. Sib-pair genetic linkage of the Lp(a) trait revealed that single nucleotide polymorphism rs10455872 was significantly associated with OxPL-apoB after adjusting for Lp(a). CONCLUSIONS: OxPL-apoB and other biomarkers of oxidized lipoproteins are highly heritable cardiovascular risk factors that suggest novel genetic origins of atherothrombosis.

Adrenocortical scavenger receptor class B type I deficiency exacerbates endotoxic shock and precipitates sepsis-induced mortality in mice.

Scavenger receptor class B type I (SR-BI)-deficient mice display reduced survival to endotoxic shock and sepsis. The understanding of the mechanisms underlying SR-BI protection has been hampered by the large spectrum of SR-BI functions and ligands. It notably plays an important role in the liver in high-density lipoprotein metabolism, but it is also thought to participate in innate immunity as a pattern recognition receptor for bacterial endotoxins, such as LPS. In this study, we sought to determine the tissue-specific contribution of SR-BI in the hyperinflammatory response and high mortality rates observed in SR-BI(-/-) mice in endotoxicosis or sepsis. Restoring plasma levels of high-density lipoprotein, which are critical lipoproteins for LPS neutralization, did not improve acute outcomes of LPS injection in SR-BI(-/-) mice. Mice deficient for SR-BI in hepatocytes, endothelial cells, or myeloid cells were not more susceptible to LPS-induced death. However, if SR-BI ablation in hepatocytes led to a moderate increase in systemic inflammatory markers, SR-BI deficiency in myeloid cells was associated with an anti-inflammatory effect. Finally, mice deficient for SR-BI in the adrenal cortex, where the receptor provides lipoprotein-derived cholesterol, had impaired secretion of glucocorticoids in response to stress. When exposed to an endotoxin challenge, these mice exhibited an exacerbated systemic and local inflammatory response, reduced activation of atrophy genes in muscle, and high lethality rate. Furthermore, polymicrobial sepsis induced by cecal ligature and puncture resulted in early death of these animals. Our study clearly demonstrates that corticoadrenal SR-BI is a critical element of the hypothalamic-pituitary-adrenal axis to provide effective glucocorticoid-dependent host defense after an endotoxic shock or bacterial infection.

Statin-induced immunomodulation alters peripheral invariant natural killer T-cell prevalence in hyperlipidemic patients.

PURPOSE: To assess the difference in the prevalence of invariant Natural Killer T (iNKT) lymphocytes between hyperlipidemic and control individuals and to evaluate changes in iNKT cell levels after 6 months lipid lowering therapy. METHODS: A total of 77 hyperlipidemic individuals (54 ± 5 years) were assigned to simvastatin 40 mg or ezetimibe 10 mg daily for 6 months. Fifty individuals with normal cholesterol levels were used as control. iNKT cells were measured by flow cytometry in peripheral blood. RESULTS: Patients with hypercholesterolemia had significantly lower iNKT cell levels (percentage on the lymphocyte population) compared to control group (0.16 ± 0.04% vs 0.39 ± 0.08%, p = 0.03). iNKT cells significantly increased after 6 months treatment with simvastatin (from 0.15 ± 0.04% to 0.28 ± 0.11%, p = 0.03) but not with ezetimibe (from 0.16 ± 0.05% to 0.17 ± 0.06%, p = 0.55). Simvastatin treatment did not alter the activation status of iNKT cells as measured by HLA-DR expression. Changes of iNKT cells were independent from changes in total (r(2) = 0.009, p = 0.76) or LDL cholesterol (r(2) = 0.008, p = 0.78) reached by simvastatin. CONCLUSIONS: Hyperlipidemic patients have reduced numbers of iNKT in peripheral circulation compared to individuals with normal cholesterol levels. Their number is increasing after long term administration of simvastatin 40 mg but not after ezetimibe.

Effect of fish oil supplementation in pregnancy on the fatty acid composition of erythrocyte phospholipids and breast milk lipids.

To investigate the effect of n-3 polyunsaturated fatty acid (PUFA) supplementation on the fatty acid composition of erythrocyte phospholipids and breast milk lipids, pregnant Brazilian women in the 30th week of gestation were randomized to supplement their usual diet with 2 g/day of fish oil (FO group) or primrose oil (PO group, control) capsules for 15 days. Erythrocyte phospholipids from FO group had proportionally higher docosahexaenoicacid and eicosapentaenoic acid levels and furthermore, the ratio of n-6/n-3 PUFA was significantly lower in the breast milk lipids compared with the control group. Assessment of plasma anti-oxLDL autoantibodies and thiobarbituric acid-reactive substance concentration demonstrated that both groups had the same levels and they were unaltered by supplementations.

Prevalence of dyslipidaemia among HIV-infected patients receiving combination antiretroviral therapy in North Shewa, Ethiopia.

BACKGROUND: Data on the burden of dyslipidaemia among people with HIV undergoing antiretroviral therapy (ART) in sub-Saharan Africa are limited and little is known about the factors contributing for poor lipid profiles. The aim of this study was to determine the prevalence of dyslipidaemia and factors associated with lipid levels among HIV-infected patients receiving first-line combination ART in North Shewa, Ethiopia. METHODS: A cross-sectional study was conducted between April and December 2018 among 392 HIV-infected adults receiving first-line ART for at least six months at the ART clinic of Mehal Meda Hospital in North Shewa, Ethiopia. Blood samples were collected for determination of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), and CD4 counts. Logistic regression analysis was used to determine factors associated with lipid abnormalities. RESULTS: The prevalence of dyslipidaemia was 59.9% (95% CI 55.0-64.7%). High TC, high TG, low HDL-c, and high LDL-c were obtained in 47.3%, 30.9%, 19.4% and 29.6%, respectively. Fifty-four participants (13.8%) had high ratio of TC/HDL-c (TC/HDL-c ratio ≥ 5). Older age was independently associated with high TC (AOR = 2.51, 95% CI 1.64-3.84), high TG (AOR = 2.95, 95% CI 1.85-4.71), low HDL-c (AOR = 2.02, 95% CI 1.17-3.50), and high LDL-c (AOR = 3.37, 95% CI 2.08-5.47). Living in an urban area (AOR = 2.61, 95% CI 1.16-6.14) and smoking (AOR = 3.61, 95% CI 1.06-12.34) were associated with low HDL-c. Participants with longer duration of ART use were more likely to have high TG (AOR = 1.86, 95% CI: 1.13-3.07), low HDL-c (AOR = 3.47, 95% CI: 1.75-6.80), and high LDL-c (AOR = 2.20, 95% CI 1.30-3.71). High BMI was independently associated with higher TC (AOR = 2.43, 95% CI 1.19-4.97), high TG (AOR = 4.17, 95% CI 2.01-8.67) and high LDL-c (AOR = 6.53, 95% CI 3.05-13.98). CONCLUSIONS: We found a high prevalence of dyslipidaemia among HIV-infected patients receiving first-line ART in North Shewa, Ethiopia. There is a need for monitoring of blood lipid levels in patients with HIV on long term first-line ART with a special attention to be focused on older age, urban residents, longer duration of ART use, high BMI and smokers.

An ODE model of early stages of atherosclerosis: mechanisms of the inflammatory response.

Atherosclerosis is a chronic disease of the large arteries, characterized by fatty cholesterol-filled streaks and plaque build-up within the artery wall. Within the past decade, inflammation has been determined as a crucial factor in all stages of lesion formation, however, many of the mechanisms involved are not yet fully understood. We present a simplified ODE model that explores the role of inflammation in atherosclerosis. The model incorporates two of the main lesion constituents, cholesterol-carrying modified Low Density Lipoproteins (LDLs) and macrophage foam cells. Their complex interactions are combined into general functions, and the long-term model behaviour is investigated through phase plane analysis and simulations. Our results indicate that the underlying mechanisms of macrophage uptake of modified LDL can have a deep impact on the cellular dynamics in the lesion. Our model demonstrates that it is macrophage proliferation and constant signalling to the endothelial cells, rather than an increasing influx of modified LDL, that drives lesion instability.

Serum YKL40: A novel potential link between inflammation and dyslipidemia in acne vulgaris.

BACKGROUND: Acne vulgaris (AV) is an inflammatory skin disorder that may be associated with metabolic disorders. The relation between lipid profile in acne is not widely investigated. Chitinase-3-like protein 1 (YKL-40) has been found to be implicated in different inflammatory conditions. AIMS: We aimed at investigating the role YKL-40 in acne pathogenesis and associated dyslipidemia in acne patients. PATIENTS/METHODS: This study included 50 acne vulgaris patients and 30 matched control subjects. Serum YKL-40 in addition to lipid profile were assessed in all studied subjects. RESULTS: Serum YKL-40 level was significantly elevated in acne patients than healthy controls (P < .001). We also found a significant positive correlations between serum YKL-40, serum TGs, TC, and LDL-C (P value: .022, .001, .017 respectively) while, a significant negative correlation between serum YKL-40 and HDL-c (P value: .036) was detected. CONCLUSION: Our study results suggest that YKL-40 might have a role in AV pathogenesis. In addition, it could provide a new potential link between inflammation and dyslipidemia observed in acne patients.

Cardiovascular disease parameters in periodontitis.

BACKGROUND: Recently, there has been an increasing in the impact of oral health on atherosclerosis and subsequent cardiovascular disease. The aim of this study is to investigate the association between chronic periodontitis and cardiovascular risk markers. METHODS: Forty patients with periodontitis and 40 healthy gender-, body mass index-, and age-matched individuals were compared by measuring total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, levels of cytokines, antibodies against oxidized low-density lipoprotein, thiobarbituric acid reactive substances, total and differential white blood cell counts, and the non-linear index of refraction. RESULTS: The levels of triglycerides and high-density lipoprotein in periodontitis patients were significantly higher and lower, respectively (P = 0.002 and P = 0.0126), compared to controls. Total cholesterol, low-density lipoprotein, and lipid peroxide levels were the same in both groups (P = 0.2943, P = 0.1284, and P = 0.067, respectively). Interleukin (IL)-6 and -8, antibodies against oxidized low-density lipoprotein, and leukocyte and neutrophil counts were significantly higher in periodontitis patients (P <0.05). The value of the non-linear index of refraction of low-density lipoprotein solutions was higher in the controls (P = 0.015) compared to individuals with periodontitis. CONCLUSION: Our results confirmed and further strengthened the suggested association between coronary artery disease and periodontitis.

Lipid lowering drugs and inflammatory changes: an impact on cardiovascular outcomes?

Inflammatory changes are responsible for maintenance of the atherosclerotic process and may underlie some of the most feared vascular complications. Among the multiple mechanisms of inflammation, the arterial deposition of lipids and particularly of cholesterol crystals is the one responsible for the activation of inflammasome NLRP3, followed by the rise of circulating markers, mainly C-reactive protein (CRP). Elevation of lipoproteins, LDL but also VLDL and remnants, associates with increased inflammatory changes and coronary risk. Lipid lowering medications can reduce cholesterolemia and CRP: patients with elevations of both are at greatest cardiovascular (CV) risk and receive maximum benefit from therapy. Evaluation of the major drug series indicates that statins exert the largest LDL and CRP reduction, accompanied by reduced CV events. Other drugs, mainly active on the triglyceride/HDL axis, for example, PPAR agonists, may improve CRP and the lipid pattern, especially in patients with metabolic syndrome. PCSK9 antagonists, the newest most potent medications, do not induce significant changes in inflammatory markers, but patients with the highest baseline CRP levels show the best CV risk reduction. Parallel evaluation of lipids and inflammatory changes clearly indicates a significant link, both guiding to patients at highest risk, and to the best pharmacological approach. Key messages Lipid lowering agents with "pleiotropic" effects provide a more effective approach to CV prevention In CANTOS study, patients achieving on-treatment hsCRP concentrations ≤2 mg/L had a higher benefit in terms of reduction in major CV events The anti-inflammatory activity of PCSK9 antagonists appears to be of a minimal extent.

[The autoimmune features of vasculopathies]. / Vasculopathiák autoimmun vonatkozásai.

In the development of atherosclerotic plaques we can identify three autoantigens, the pathological value of which has been proven by experimental and clinical data. These antigens are the 60 kDa heat-shock-protein, beta2-glycoprotein I and oxidized LDL. They have role in the antigen-specific T-cell differentiation processes, moreover, against these antigens autoantibodies are produced, which have prothrombotic activity, leading to the acceleration of atherosclerosis. In autoimmune diseases besides these factors other mechanisms are present, which lead to the development of autoimmune vasculopathies. The current review gives an overview of these vasculopathies.

Accelerated atheroma in the antiphospholipid syndrome.

Increased cardiovascular morbidity and mortality due to the pre-mature or accelerated development of atherosclerosis has been reported in patients with systemic autoimmune diseases such as systemic lupus erythematosus. These findings motivated a great deal of research into the role of autoimmunity in atherogenesis. The relationship between atherosclerosis and cholesterol metabolism to atherosclerosis has been well established. However, the participation of newer inflammatory and immunologic mechanisms are emerging as relevant factors for the initiation and progression of atherosclerotic lesions.

Detection of electronegative low density lipoprotein (LDL-) in plasma and atherosclerotic lesions by monoclonal antibody-based immunoassays.

OBJECTIVES: To produce a monoclonal antibody (MAb) against electronegative LDL (LDL-) for detecting this modified lipoprotein in blood plasma and tissues. DESIGN AND METHODS: LDL- was isolated from human blood plasma and used as an antigen for immunization of Balb/c mice. Lymphocytes of immunized mice were fused with myeloma cells (SP2/0) to obtain the hybridomas. LDL- was detected in blood plasma and atherosclerotic lesions of humans and rabbits by MAb-based ELISA and immunohistochemistry, respectively. RESULTS: LDL- concentrations were higher (P < 0.05) in the blood plasma of hypercholesterolemic subjects (HC, 248 +/- 77 mg/dL of total cholesterol) than in normolipidemic subjects (NL, 173 +/- 82 mg/dL of total cholesterol) and rabbits (HC, 250 +/- 15 mg/dL of cholesterol versus NL, 81 +/- 12 mg/dL of cholesterol). Moreover, LDL- was detected in the atherosclerotic lesions of humans and rabbits. CONCLUSION: These MAb-based immunoassays are adequate to detect LDL- in biological samples and represent an important tool for investigating the role of LDL- in atherosclerosis.

Coronary artery calcification, systemic inflammation markers and mineral metabolism in a peritoneal dialysis population.

AIMS: To assess the prevalence of coronary artery calcification (CAC) in peritoneal dialysis (PD) patients and to determine whether comorbidities such as inflammation, dyslipidemia and mineral metabolism disorders correlate with its development. METHODS: Forty-nine PD patients (45% male; median age, 52 years) were submitted to multislice computed tomography. Inflammatory markers, anti-oxidized LDL antibody, calcium-phosphate balance and lipid profiles were assessed. RESULTS: Twenty-nine patients (59.2%) presented CAC (median calcium score, 234.7 Agatston units). Patients with CAC were older than those without, more frequently presented a history of coronary artery disease or hypertension and had lower HDL cholesterol levels, as well as presenting higher levels of osteoprotegerin and LDL oxidation. The logistic regression revealed that the independent determinants of CAC were age (odds ratio = 1.12; p = 0.006) and number of prescribed anti-hypertensive drugs (odds ratio = 2.38; p = 0.048). When the population was stratified by calcium score quartile, soluble Fas levels were significantly higher in patients with severe calcification. In patients younger than 45, CAC correlated positively with phosphorus levels (r = 0.52; p = 0.04). CONCLUSION: In PD patients, CAC is highly prevalent. Our results indicate that conditions such as inflammation and mineral disturbances are associated with its development.

Simvastatin Efficiently Lowers Small LDL-IgG Immune Complex Levels: A Therapeutic Quality beyond the Lipid-Lowering Effect.

We investigated a polyethylene glycol non-precipitable low-density lipoprotein (LDL) subfraction targeted by IgG and the influence of statin therapy on plasma levels of these small LDL-IgG-immune complexes (LDL-IgG-IC). LDL-subfractions were isolated from 6 atherosclerotic subjects and 3 healthy individuals utilizing iodixanol density gradient ultracentrifugation. Cholesterol, apoB and malondialdehyde (MDA) levels were determined in each fraction by enzymatic testing, dissociation-enhanced lanthanide fluorescence immunoassay and high-performance liquid chromatography, respectively. The levels of LDL-IgG-IC were quantified densitometrically following lipid electrophoresis, particle size distribution was assessed with dynamic light scattering and size exclusion chromatography. The influence of simvastatin (40 mg/day for three months) on small LDL-IgG-IC levels and their distribution among LDL-subfractions (salt gradient separation) were investigated in 11 patients with confirmed coronary artery disease (CAD). We demonstrate that the investigated LDL-IgG-IC are small particles present in atherosclerotic patients and healthy subjects. In vitro assembly of LDL-IgG-IC resulted in particle density shifts indicating a composition of one single molecule of IgG per LDL particle. Normalization on cholesterol levels revealed MDA values twice as high for LDL-subfractions rich in small LDL-IgG-IC if compared to dominant LDL-subfractions. Reactivity of affinity purified small LDL-IgG-IC to monoclonal antibody OB/04 indicates a high degree of modified apoB and oxidative modification. Simvastatin therapy studied in the CAD patients significantly lowered LDL levels and to an even higher extent, small LDL-IgG-IC levels without affecting their distribution. In conclusion simvastatin lowers levels of small LDL-IgG-IC more effectively than LDL-cholesterol and LDL-apoB levels in atherosclerotic patients. This antiatherogenic effect may additionally contribute to the known beneficial effects of this drug in the treatment of atherosclerosis.

In vivo low density lipoprotein oxidation relates to coronary reactivity in young men.

OBJECTIVES: This study was undertaken to examine the relation of in vivo low density lipoprotein (LDL) oxidation and other lipid risk factors to coronary reactivity in normal subjects. BACKGROUND: Experimental studies have shown that oxidized LDL (ox-LDL) particles are injurious to the vascular wall by impairing its normal vasodilator function. METHODS: We used noninvasive positron emission tomographic (PET) imaging with intravenous dipyridamole to measure coronary flow reserve, a marker of coronary endothelial and smooth muscle function, in 30 healthy men (mean [+/-SD] age 34.4 +/- 3.2 years). As a marker of in vivo LDL oxidation, the autoantibody titer against ox-LDL was measured by the enzyme-linked immunosorbent assay method. RESULTS: Plasma levels of autoantibody titer against ox-LDL were inversely associated with coronary flow reserve (r = -0.42, p = 0.023). High LDL cholesterol levels (above median > 3.0 mmol/liter) were associated with a low coronary flow reserve only in subjects expressing simultaneously high levels of ox-LDL titer (above median). Subjects with simultaneously high levels of LDL cholesterol and ox-LDL titer had lower coronary flow reserve values than subjects in other groups (3.89 vs. > 5.0 in other groups, p = 0.066). CONCLUSIONS: These data provide evidence for the role of ox-LDL in affecting the coronary reactivity in vivo and support the concept that oxidative modification of LDL particles provides a mechanism by which high LDL concentrations exhibit injurious effects on the coronary vascular bed.

Clinical significance of antibody against oxidized low density lipoprotein in patients with atherosclerotic coronary artery disease.

OBJECTIVES: This study was designed to establish the clinical significance of antibodies against oxidized low density lipoprotein (anti-Ox-LDL) titer in atherosclerotic coronary artery disease (CAD). BACKGROUND: Oxidative modification of LDL, which plays a key role in the development of atherosclerosis, induces immunogenic epitopes in the LDL molecule, and the presence of anti-Ox-LDL has been demonstrated in human sera. METHODS: Anti-Ox-LDL titer was measured by enzyme-linked immunosorbent assay in 108 patients who had angiographically verified CAD, and 31 patients who had chest pain but no significant CAD, as controls. RESULTS: The anti-Ox-LDL titer was higher (p < 0.01) in patients with multivessel CAD (19.4 +/- 10.1 AcU/ml, n = 68) than in the controls (9.8 +/- 4.1). However, no significant difference was shown between the single-vessel CAD group (15.1 +/- 6.4, n = 40) and the controls, or between the multivessel CAD group and the single-vessel CAD group. The titer was higher in patients with unstable angina (21.5 +/- 11.8 AcU/ml, n = 20, p < 0.01), or in patients with acute myocardial infarction (23.1 +/- 12.0, n = 20, p < 0.01) than in patients with stable-effort angina or old myocardial infarction (12.2 +/- 8.6, n = 68). Multiple logistic regression analysis indicated that the anti-Ox-LDL titer most powerfully discriminated CAD patients from controls (odds ratio [OR]: 1.20, 95% confidence interval [CI]: 1.07-1.33, p = 0.0006) and acute coronary syndrome from chronic CAD (OR: 1.09, 95% CI: 1.04-1.14, p = 0.0008). CONCLUSIONS: Serum anti-Ox-LDL titer not only can predict a presence of atherosclerotic CAD but also may be a marker of plaque instability. Low density lipoprotein oxidation may play an important role in the development of plaque instability.