© 2001 American Heart Association, Inc.
Atherosclerosis and Lipoproteins |
Circulating Autoantibodies to Oxidized LDL Correlate With Arterial Accumulation and Depletion of Oxidized LDL in LDL Receptor–Deficient Mice
From the Divisions of Cardiovascular Diseases (S.T.) and Endocrinology and Metabolism (W.P., J.L.W.), Department of Medicine, University of California, San Diego.
Correspondence to Sotirios Tsimikas, MD, Department of Medicine, Division of Cardiology, University of California San Diego, 9500 Gilman Dr, BSB 1080, La Jolla, CA 92093-0682. E-mail stsimikas{at}ucsd.edu
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Abstract |
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Abstract—Autoantibodies to oxidized low density lipoprotein (OxLDL) are elevated in some human populations with increased risk of atherosclerosis. To determine whether autoantibody levels to epitopes of OxLDL reflect the extent of aortic atherosclerosis and the content of OxLDL, we measured IgG and IgM autoantibody titers to malondialdehyde (MDA)-LDL and copper-oxidized LDL (Cu-OxLDL) in 43 LDL receptor–deficient mice consuming atherogenic and regression diets. Antibody titers were correlated to percent atherosclerotic surface area, aortic weight, and aortic OxLDL content, measured as the in vivo uptake of 125I-MDA2, a monoclonal antibody to MDA-LDL. All mice were fed an atherogenic diet for 6 months, and 1 group was euthanized. The other 3 groups were fed an atherogenic diet (fat/CHOL group), normal mouse chow (chow group), or mouse chow supplemented with vitamins E and C (chow+VIT group) for an additional 6 months. After dietary intervention, compared with their own baseline, autoantibody titers to MDA-LDL and Cu-OxLDL increased significantly in the fat/CHOL group, whereas they did not change or decreased significantly in the chow and chow+VIT groups. Aortic weight and surface area showed significant progression in the fat/CHOL group, mild progression in the chow group, and no progression in the chow+VIT group (P<0.001), whereas OxLDL content actually decreased in the latter 2 groups (P<0.001). Significant correlations were seen with MDA-LDL autoantibody titers and OxLDL content (IgM, R=0.64 and P=0.0009; IgG, R=0.52 and P=0.009), as well as with percent surface area and aortic weight. These data support the hypothesis that autoantibody titers to OxLDL reflect changes in OxLDL content in atherosclerotic lesions of LDL receptor–deficient mice. Whether autoantibody titers to OxLDL will provide similar valuable insights into the extent of human atherosclerosis, particularly anatomic measurements of plaque burden and OxLDL content, remains to be determined.
Key Words: regression • progression • atherosclerosis • lipoproteins • autoantibodies
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Introduction |
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It is generally accepted that oxidative modification of LDL is intimately involved in the initiation and progression of atherosclerotic lesions.1 Human atherosclerotic lesions have been shown to contain abundant quantities of oxidized lipoproteins within foam cells and in the extracellular space.2 3 4 5 6 In patients with myocardial infarction, atherosclerotic lesions undergoing plaque rupture, erosion, and thrombosis often contain large lipid pools with significant amounts of extracellular oxidized lipids and oxidized LDL (OxLDL).7 8 Indeed, recent evidence suggests that plasma levels of malondialdehyde (MDA)-LDL, an epitope of OxLDL derived from lipid peroxidation, is elevated in patients with coronary artery disease and is a strong predictor of acute coronary syndromes.9 10
The immune system plays a significant role in modulating the development of atherosclerosis.11 12 Our laboratory originally demonstrated that OxLDL is highly immunogenic and that autoantibodies to various epitopes of OxLDL are prevalent in humans and animals with atherosclerosis.2 13 14 Because LDL undergoes oxidative modification in vivo in atherosclerotic lesions, it is therefore likely that OxLDL within atherosclerotic tissues may induce the generation of circulating autoantibodies.2 3 14 15 16 17 18 This is also supported by the observation that a surprisingly high percentage of T lymphocytes isolated from human atherosclerotic lesions specifically recognizes OxLDL, suggesting that they are involved in immune activation and inflammation of atherosclerotic plaques.19 A corollary of these observations is that the autoantibody titers may reflect the atherogenic process. Indeed, previous studies have shown that autoantibody titers to OxLDL are elevated in humans and animals with atherosclerosis.11 20 However, the relationship between the extent of atherosclerosis and the humoral immune response is complex. Most of the human studies have been hampered by the lack of a precise cumulative assessment of atherosclerosis, and the autoantibody correlations have, in large part, been based on clinical surrogates. In addition, only very limited data from animal models are available on the relationship between autoantibody titers and the overall extent of atherosclerosis,21 and no published studies exist addressing the relationship between autoantibody titers and the progression or regression of atherosclerosis.
The most commonly used measure of atherosclerosis in animal models is percent atherosclerotic surface area of the aorta. In a previous study in LDL receptor–deficient (LDLR-/-) mice, we have shown that OxLDL content may be measured by intravenous injection of radiolabeled oxidation-specific antibodies (125I-MDA2).22 In that study, we induced lesion progression and regression and measured 3 parameters of atherosclerotic burden, ie, percent atherosclerotic surface area, aortic weight, and aortic uptake of 125I-MDA2. Focusing on the relationship between these parameters, we showed that in progressing atherosclerosis induced by a high-fat high-cholesterol diet, plaque uptake of 125I-MDA2 was correlated exceedingly well with the percent atherosclerotic surface area and the aortic weight (which reflects plaque volume). After prolonged exposure of mice with preexisting lesions to regular mouse chow with or without antioxidants, the 125I-MDA2 uptake indicated "regression," ie, reduced lesion content of OxLDL, which was confirmed by immunostaining. In contrast, the percent surface area and aortic weight showed slight or no progression of atherosclerosis rather than regression. The 125I-MDA2 uptake technique therefore complements the traditional anatomic measurements of plaque size during lesion progression but is more sensitive to decreases in lesion content of OxLDL.
Using the sera and data on atherosclerosis from that study, we now address the hypothesis that autoantibodies to epitopes of OxLDL reflect the progression and regression of experimental atherosclerosis assessed by anatomic measurements of atherosclerosis and determination of OxLDL content.
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Methods |
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Animal Models and Dietary Intervention
The design of the intervention study has been described in detail previously22 and is summarized in Figure 1
. In brief, 6-month-old male
LDLR-/- mice (n=43) were placed on an
atherogenic diet containing 21% milk fat and 1.25%
cholesterol for 6 months to induce
atherosclerosis. The mice were then divided into 4
groups. Group I (n=13) was euthanized as the baseline control group.
For an additional 6 months, groups II (chow group, n=10) and III
(chow+VIT group, n=10) were placed on
hypocholesterolemic "regression diets" consisting
of regular chow and of regular chow supplemented with antioxidants
(1.0% vitamin E added to the chow and 0.05% vitamin C added to the
drinking water), respectively. Group IV (fat/CHOL group, n=10) was
continued on the high-fat/cholesterol diet for 6 months.
Atherosclerosis was measured in terms of percent
Sudan-positive aortic surface area, aortic weight, and uptake of
125I-MDA2, as previously
described.22 Throughout the
study, blood samples were obtained from the retro-orbital plexus and
placed in EDTA tubes, and the plasma was isolated and stored at
-70°C. These studies were approved by the Animal Subjects Committee
of the University of California, San Diego.
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Determination of Antibody Binding to MDA-LDL
and Cu-OxLDL
The levels of IgM and IgG autoantibodies binding to
MDA-LDL (anti–MDA-LDL) and Cu-OxLDL (anti–Cu-OxLDL) were determined
in murine sera by use of a chemiluminescence
ELISA.23 Autoantibody levels
were determined in individual samples from all 4 groups of mice after
the initial 6 months of the atherogenic diet and in the chow, chow+VIT,
and fat/CHOL groups after 6 more months of dietary intervention.
Antigens for the ELISA, MDA-LDL or Cu-OxLDL, were generated as
described.24 In this assay, 5
µg/mL of the antigen in 50 mmol/L Tris-buffered saline (TBS), pH
7.5, containing 0.27 mmol/L EDTA, 0.02% azide, and 20 µmol/L
butylated hydroxytoluene (dilution buffer), was added to each well of a
96-well white round-bottomed MicroFluor microtitration plate (Dynatech
Laboratories, Inc) and incubated overnight at 4°C. Plates were washed
4 times with washing buffer (TBS containing 0.27 mmol/L EDTA, 20
µmol/L butylated hydroxytoluene, 0.02% NaN3,
and 0.001% aprotinin) with the use of an automated plate washer.
Murine sera were diluted 1:500 in dilution buffer containing 1% BSA,
and 50 µL was added to each well and incubated for 1 hour at room
temperature. After 4 washes, plates were incubated with 50 µL per
well of an alkaline phosphatase–labeled goat anti-mouse IgG (
-chain
specific) or phosphatase-labeled goat anti-mouse IgM (µ-chain
specific, both from Sigma) for 1 hour at room temperature. These
antibodies were diluted in 1% BSA/TBS according to the supplier’s
specifications. After the plates were washed, 25 µL of a 50%
solution of Lumi-Phos 530 (Lumigen) was added to each well, and the
plates were incubated for 1 to 2 hours at room temperature in the dark,
and luminescence was determined. Antibody binding was measured as
relative light units (RLU) in 100 milliseconds. Triplicate
determinations were performed for each plasma sample. Measurement of
antibody binding to a given antigen was performed in a single assay. A
high and a low standard serum was included on each plate of a given
assay to detect potential variations between microtitration plates. The
intra-assay coefficients of variation for these assays were 6% to
10%.
Statistical Analysis
Statistical analyses were performed with
ANOVA and paired t test for
post hoc analysis when appropriate. Correlations between
parameters of atherosclerosis and
autoantibody titers were tested by linear regression analysis.
Data shown are mean±SD, unless otherwise
indicated.
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Results |
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Autoantibody Determinations
The mean autoantibody levels in the entire cohort of 43 mice after 6 months of the atherogenic diet were as follows: anti–MDA-LDL IgG, 2525±1228 RLU; anti–MDA-LDL IgM, 15182±6412 RLU; anti–Cu-OxLDL IgG, 1285±587 RLU; and anti–Cu-OxLDL IgM, 3562±1777 RLU. These levels are generally much higher than those found in chow-fed C57B6 mice.14 24 At the end of the initial 6 months on a high-fat diet, mice were divided into the 4 experimental groups. There were no significant differences in the autoantibody titers among the groups except for the anti–MDA-LDL IgM titers, which were higher in the mice assigned to the chow and chow+VIT groups (P=0.02, data not shown). Note that the assignment of animals to the groups was aimed at matching cholesterol levels (and thus, presumably, atherosclerosis) at baseline, whereas no matching for antibody levels was performed as part of the original design.22 The baseline control group was euthanized at this time, whereas the other 3 groups were continued under the study protocol (Figure 1
) for another 6 months. At the end of the study,
levels of anti–MDA-LDL and anti–Cu-OxLDL autoantibody titers were
consistently higher (1.2- to 1.5-fold) in the fat/CHOL group
compared with the other groups
(Table).
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Because this comparison uses mice at different time points
(the baseline control group was 6 months younger than the other 3
groups at the terminal autoantibody measurement) and because starting
levels of autoantibodies were not equal, for all subsequent
analyses, we compared the changes in autoantibody levels for
each individual animal within each group, ie, before and after the
dietary intervention.
Figure 2A summarizes the mean changes in OxLDL autoantibody
levels in the 3 intervention groups. When changes were compared within
each group, in the fat/CHOL group, there was a significant increase in
all autoantibodies to OxLDL, with anti–MDA-LDL IgG showing the
greatest increase (81%,
P<0.0001 compared with the
preintervention values in the same group of mice). In contrast, in the
chow and chow+VIT groups, the IgG autoantibody titers for anti–MDA-LDL
and anti–Cu-OxLDL did not change, whereas the IgM titers actually
decreased significantly after the regression/antioxidant diet. The
corresponding changes in the cumulative measures of
atherosclerosis and plaque OxLDL content are shown in
Figure 2B. Because only 1 measurement was possible in these
parameters (at the time of euthanasia), the
atherosclerosis indices were compared with those in the
baseline control group. As expected, because of the continued
progression of lesions in the fat/CHOL group, all 3
atherosclerosis indices increased significantly
compared with those in the baseline control group
(P<0.001). There was reduced
progression of atherosclerosis measured by surface area
(P<0.001) but not aortic
weight in the chow group. No significant changes in surface area or
aortic weight were seen in the chow+VIT group. In contrast, significant
reductions were noted in the OxLDL content, as reflected by
125I-MDA2 aortic uptake, in the chow and
chow+VIT groups (P<0.001 for
both). Therefore, MDA-LDL and Cu-OxLDL autoantibody levels
qualitatively reflected the changes seen in the
atherosclerosis indices and OxLDL
content.
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Correlations Between Autoantibody Levels and
Atherosclerosis Indices
Correlations were carried out between
atherosclerosis indices and the percent change in OxLDL
autoantibody levels.
Figure 3 shows the correlations between MDA-LDL autoantibody
titers and the percent surface area, aortic weight, and uptake of
125I-MDA2. Highly significant correlations
were seen with atherosclerosis parameters
and anti–MDA-LDL autoantibodies, particularly with aortic uptake of
125I-MDA2 (for IgM,
R=0.64 and
P=0 0.0009; for IgG,
R=0.52 and
P=0.009). The correlations with
anti–Cu-OxLDL IgG were more modest (for
125I-MDA2,
R=0.42 and
P=0.044; for aortic weight,
R=0.45 and
P=0.033; and for percent
surface area, R=0.37 and
P=0.075). A trend was noted for
the correlation between anti–Cu-OxLDL IgM and
125I-MDA2 uptake
(R=0.37,
P=0.09), but there was no
correlation with lesion area or weight.
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Discussion |
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In the present study, we demonstrate that autoantibody titers to OxLDL are significantly influenced by diet and antioxidant supplementation in atherosclerotic LDLR-/- mice, and we provide evidence that they indicate lesion progression as well as depletion of OxLDL during dietary regression. Plasma autoantibody levels to OxLDL increased significantly in mice continually fed an atherogenic diet but did not change or actually decreased in mice that were switched to a regression diet consisting of normal mouse chow or chow supplemented with vitamins E and C. A good correlation with traditional measures of atherosclerosis, such as percent atherosclerotic surface area or aortic weight, was noted for anti–MDA-LDL IgG and IgM autoantibodies. An even stronger correlation was noted with the in vivo aortic uptake of 125I-MDA2, which reflects the in vivo OxLDL content of lesions. These data provide evidence that in vivo 125I-MDA2 aortic uptake accurately reflects the presence of MDA-LDL and malondialdehyde-lysine epitopes within the plaque in atherosclerosis progression and "regression", ie, depletion of MDA-LDL and malondialdehyde-lysine epitopes.
In humans, elevated titers of OxLDL autoantibodies have been documented in patients with myocardial infarction and angiographically documented coronary artery disease, peripheral vascular disease, and accelerated progression of carotid atherosclerosis.20 25 26 27 28 Elevated titers also seem to predict impaired endothelial function by demonstrating an inverse correlation with forearm blood flow in hypercholesterolemic smokers and with reduced coronary flow reserve assessed by positron emission tomographic scanning.29 30 31 In animal models, apoE-deficient and LDLR-/- mice have been shown to have elevated titers of autoantibodies to multiple epitopes of OxLDL.13 14 21 Freigang et al32 have also shown that immunization of LDLR-/- mice with homologous MDA-LDL results in markedly increased antibody titers to OxLDL, which were associated with a protective role against atherosclerosis. More recently, Cyrus et al33 showed that disruption of the 12/15-lipoxygenase gene in apoE-deficient mice resulted in reduced aortic root lesions and markedly diminished autoantibody titers to MDA-LDL and Cu-OxLDL. These human and animal studies clearly demonstrate that the humoral responses to OxLDL reflect changes within atherosclerotic plaques.
The potential role of autoantibodies to OxLDL as indicators
of the regression of atherosclerosis has not been
previously studied. Our data demonstrate that autoantibody titers to
epitopes of OxLDL are well correlated with changes in atherosclerotic
lesions, particularly their content of OxLDL. We have previously shown
that in vivo aortic uptake of 125I-MDA2 is a
sensitive marker of the progression and regression of
atherosclerosis. The fact that the uptake of
125I-MDA2 decreased as a result of
regression diets clearly suggests that the lesion content of OxLDL
decreases, and this was confirmed by
immunohistochemistry.22
Although antigen formation may also occur elsewhere in lipid-rich
tissues and may equally be affected by the regression diets, our
results support the assumption that the decrease in antibody titers is
at least in part the result of the reduced presence of OxLDL in the
aorta. The analogy in the changes in autoantibody titers and
atherosclerosis
(Figure 2) and the correlations between the these
parameters
(Figure 3) also support this conclusion.
The autoantibody titers were qualitatively similar in the chow and chow+VIT groups, but the surface area and aortic weight were different, although only the surface area was statistically significant between the 2 groups. This apparent discrepancy likely reflects the fact that the autoantibody titers more accurately indicate the content of OxLDL within the lesions, which were similarly reduced in both groups to the same extent, rather than other lesion components that contribute to plaque mass.
The presumed etiology of the bulk of the "oxidation-specific" antigens responsible for the generation of these autoantibodies is thought to be the vessel wall. However, it is possible that the marked hypercholesterolemia could have induced increased oxidation-specific epitopes elsewhere as well.34 In addition, it has been shown that oxidized cholesterol and oxidized lipids in the diet accelerate the development of atherosclerosis in mice and rabbits.35 36 37 In those studies, the dietary levels of oxidation byproducts were significantly increased by heating vitamin E–depleted corn oil or cholesterol to 100°C for several hours. In contrast, in the present study, all diets were refrigerated until time of use and were not vitamin E–depleted. Although we did not measure the levels of dietary peroxides in the present study, the plasma vitamin E levels (corrected to total plasma cholesterol) were higher in the fat/CHOL group than in the chow group, which may have provided some antioxidant protection.22
It is not surprising that the autoantibody titers to MDA-LDL showed the best correlation with the in vivo aortic uptake of 125I-MDA2, because of the identity of the antigens. However, the observation that antibodies to Cu-OxLDL are also correlated to some extent with 125I-MDA2 aortic uptake emphasizes the fact that the uptake of 125I-MDA2 provides a representative measure of OxLDL in the artery wall, not just a measure of its content in MDA-lysine epitopes. Indeed, although MDA-LDL is only 1 of many epitopes of OxLDL, it is clearly ubiquitous in atherosclerotic lesions.3 5 6 13 15 16 38 39 The correlations with lesion size were also much better for MDA-LDL than for Cu-OxLDL autoantibodies. Besides MDA-lysine epitopes, copper-induced oxidation of LDL also generates many other epitopes, such as oxidized phospholipids. Therefore, some differences between these autoantibody measurements would be expected. Additionally, the measured plasma autoantibody levels reflect an equilibrium between rates of formation and removal as well as immune complex formation (which we did not measure in the present study), which may more accurately reflect the development or regression of lesions.11
Measurements of autoantibody titers to OxLDL have not yet been reported in human studies of dietary or pharmacological regression. Whether these measurements will be useful in the clinical arena remains to be seen. The cholesterol levels in the LDLR-/- mice after a Western-type diet are very high and are not usually seen in human subjects. The dietary regimens also resulted in drastic reductions in total cholesterol levels. The lesions induced, however, do reflect human lesions in many respects; therefore, we believe that the relevance of this model in humans is valid in principle. It is likely, however, that changes in humans will be much more modest. Nevertheless, depletion in the content of OxLDL may occur in patients treated with hypolipidemic agents and antioxidants over longer periods of time; this depletion will, in turn, be reflected in reduced autoantibody titers.
Significant effort has gone into developing techniques that provide clinically useful information on atherosclerotic lesions in patients. Unfortunately, most of the current gold-standard techniques are invasive, and we lack noninvasive techniques to either image the vessel wall or to ascertain plaque composition. The present data suggest that measurement of autoantibody titers to OxLDL can provide at least a cumulative measure of plaque OxLDL content. Whether measurement of autoantibody titers to OxLDL will be useful in assessing the regression of human atherosclerotic lesions needs to be evaluated in studies using quantitative techniques (such as intracoronary ultrasound) that completely assess the atherosclerotic plaque burden.40
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Acknowledgments |
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This investigation was supported by an National Heart, Lung, and Blood Institute (NHLBI) Mentored Clinical Scientist Development Award (HL-07444 to S.T.), by a New Investigator Award from the California Tobacco-Related Diseases Research Project (HT-0106 to S.T.), and by an NHLBI grant (HL-56989, La Jolla Specialized Center of Research in Molecular Medicine and Atherosclerosis to W.P. and J.L.W.). We would like to thank Jennifer Pattison, Florencia Casanada, Mercedes Silvestre, Elizabeth Miller, and Joseph Juliano for excellent technical assistance.
Received July 17, 2000; accepted October 6, 2000.
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References |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Tsimikas S, Witztum JL, The oxidative modification hypothesis of atherosclerosis. In: Keaney JF, ed. Oxidative Stress and Vascular Disease. Boston, Mass: Kluwer Academic Publishers; 2000:49–74.
2.
Palinski W,
Rosenfeld ME, Ylä-Herttuala S, Gurtner GC, Socher SS, Butler SW,
Parthasarathy S, Carew TE, Steinberg D, Witztum JL. Low density
lipoprotein undergoes oxidative modification in vivo.
Proc Natl Acad Sci
U S A. 1989;86:1372–1376.
3. Ylä-Herttuala S, Palinski W, Rosenfeld ME, Parthasarathy S, Carew TE, Butler S, Witztum JL, Steinberg D. Evidence for the presence of oxidatively modified low density lipoprotein in atherosclerotic lesions of rabbit and man. J Clin Invest. 1989;84:1086–1095.
4. Carpenter KL, Taylor SE, van der Veen C, Williamson BK, Ballantine JA, Mitchinson MJ. Lipids and oxidised lipids in human atherosclerotic lesions at different stages of development. Biochim Biophys Acta. 1995;1256:141–150.[Medline] [Order article via Infotrieve]
5. Piotrowski JJ, Shah S, Alexander JJ. Mature human atherosclerotic plaque contains peroxidized phosphatidylcholine as a major lipid peroxide. Life Sci. 1996;58:735–740.[Medline] [Order article via Infotrieve]
6.
Suarna C, Dean RT,
May J, Stocker R. Human atherosclerotic plaque contains both oxidized
lipids and relatively large amounts of alpha-tocopherol and
ascorbate. Arterioscler Thromb Vasc
Biol. 1995;15:1616–1624.
7.
Davies MJ,
Richardson PD, Woolf N, Katz DR, Mann J. Risk of thrombosis in human
atherosclerotic plaques: role of extracellular lipid,
macrophage, and smooth muscle cell content.
Br Heart J. 1993;69:377–381.
8.
Felton CV, Crook D,
Davies MJ, Oliver MF. Relation of plaque lipid composition and
morphology to the stability of human aortic plaques.
Arterioscler Thromb Vasc Biol. 1997;17:1337–1345.
9.
Holvoet P, Vanhaecke
J, Janssens S, van de Werf F, Collen D. Oxidized LDL and
malondialdehyde-modified LDL in patients with acute coronary
syndromes and stable coronary artery disease.
Circulation. 1998;98:1487–1494.
10.
Holvoet P, Collen
D, Van de Werf F, Malondialdehyde-modified LDL as a marker of acute
coronary syndromes.
JAMA. 1999;281:1718–1721.
11. Palinski W, Witztum JL. Immune responses to oxidative neoepitopes on LDL and phospholipids modulate the development of atherosclerosis. J Intern Med. 2000;247:371–380.[Medline] [Order article via Infotrieve]
12. Libby P, Hansson GK, Pober JS, Atherogenesis and inflammation. In: Chien KR, ed. Molecular Basis of Cardiovascular Disease. Philadelphia, Pa: Saunders; 1999:349–366.
13.
Palinski W, Ord
VA, Plump AS, Breslow JL, Steinberg D, Witztum JL. ApoE-deficient mice
are a model of lipoprotein oxidation in atherogenesis: demonstration of
oxidation-specific epitopes in lesions and high titers of
autoantibodies to malondialdehyde-lysine in serum.
Arterioscler Thromb. 1994;14:605–616.
14. Palinski W, Hörkko S, Miller E, Steinbrecher UP, Powell HC, Curtiss LK, Witztum JL. Cloning of monoclonal autoantibodies to epitopes of oxidized lipoproteins from apolipoprotein E-deficient mice: demonstration of epitopes of oxidized low density lipoprotein in human plasma. J Clin Invest. 1996;98:800–814.[Medline] [Order article via Infotrieve]
15.
Haberland ME, Fong
D, Cheng L. Malondialdehyde-altered protein occurs in
atheroma of Watanabe heritable
hyperlipidemic rabbits.
Science. 1988;241:215–218.
16.
Rosenfeld ME,
Palinski W, Ylä-Herttuala S, Butler S, Witztum JL. Distribution of
oxidation specific lipid-protein adducts and apolipoprotein B in
atherosclerotic lesions of varying severity from WHHL rabbits.
Arteriosclerosis. 1990;10:336–349.
17. Boyd HC, Gown AM, Wolfbauer G, Chait A. Direct evidence for a protein recognized by a monoclonal antibody against oxidatively modified LDL in atherosclerotic lesions from a Watanabe heritable hyperlipidemic rabbit. Am J Pathol. 1989;135:815–825.[Abstract]
18. Tsimikas S, Palinski W, Halpern SE, Yeung DW, Curtiss LK, Witztum JL. Radiolabeled MDA2, an oxidation-specific, monoclonal antibody, identifies native atherosclerotic lesions in vivo. J Nucl Cardiol. 1999;6:41–53.[Medline] [Order article via Infotrieve]
19.
Stemme S, Faber B,
Holm J, Wiklund O, Witztum JL, Hansson GK. T lymphocytes from human
atherosclerotic plaques recognize oxidized low density lipoprotein.
Proc Natl Acad Sci
U S A. 1995;92:3893–3897.
20. Ylä-Herttuala S. Is oxidized low-density lipoprotein present in vivo? Curr Opin Lipidol. 1998;9:337–344.[Medline] [Order article via Infotrieve]
21.
Palinski W,
Tangirala RK, Miller E, Young SG, Witztum JL. Increased autoantibody
titers against epitopes of oxidized LDL in LDL receptor–deficient mice
with increased atherosclerosis.
Arterioscler Thromb Vasc Biol. 1995;15:1569–1576.
22.
Tsimikas S,
Shortal BP, Witztum JL, Palinski W. In vivo uptake of radiolabeled
MDA2, an oxidation-specific monoclonal antibody, provides an accurate
measure of atherosclerotic lesions rich in oxidized LDL and is highly
sensitive to their regression.
Arterioscler Thromb Vasc Biol. 2000;20:689–697.
23. Hörkkö S, Miller E, Dudl E, Reaven P, Curtiss L, Zvailfler NJ, Terkeltaub R, Pierangeli SS, Branch DW, Palinski W, et al. Antiphospholipid antibodies are directed against epitopes of oxidized phospholipids: recognition of cardiolipin by monoclonal antibodies to epitopes of oxidized low-density lipoprotein. J Clin Invest. 1996;98:815–825.[Medline] [Order article via Infotrieve]
24.
Palinski W,
Ylä-Herttuala S, Rosenfeld ME, Butler SW, Socher SA, Parthasarathy S,
Curtiss LK, Witztum JL. Antisera and monoclonal antibodies specific for
epitopes generated during oxidative modification of low density
lipoprotein.
Arteriosclerosis. 1990;10:325–335.
25. Salonen JT, Ylä-Herttuala S, Yamamoto R, Butler S, Korpela H, Salonen R, Nyyssonen K, Palinski W, Witztum JL. Autoantibody against oxidised LDL and progression of carotid atherosclerosis. Lancet. 1992;339:883–887.[Medline] [Order article via Infotrieve]
26.
Puurunen M,
Manttari M, Manninen V, Tenkanen L, Alfthan G, Ehnholm C, Vaarala O,
Aho K, Palosuo T. Antibody against oxidized low-density lipoprotein
predicting myocardial infarction. Arch
Intern Med. 1994;154:2605–2609.
27.
Wu R, Nityanand S,
Berglund L, Lithell H, Holm G, Lefvert AK. Antibodies against
cardiolipin and oxidatively modified LDL in 50-year-old men predict
myocardial infarction. Arterioscler Thromb
Vasc Biol. 1997;17:3159–3163.
28.
Bergmark C, Wu R,
de Faire U, Lefvert AK, Swedenborg J. Patients with early-onset
peripheral vascular disease have increased levels of
autoantibodies against oxidized LDL.
Arterioscler Thromb Vasc Biol. 1995;15:441–445.
29.
Heitzer T, Luoma
J, Kurz S, Munzel T, Just H, Olschewski M, Drexler H. Cigarette smoking
potentiates endothelial dysfunction of forearm
resistance vessels in patients with
hypercholesterolemia: role of oxidized LDL.
Circulation. 1996;93:1346–1353.
30.
Heitzer T,
Ylä-Herttuala S, Wild E, Luoma J, Drexler H. Effect of vitamin E on
endothelial vasodilator function in patients with
hypercholesterolemia, chronic smoking or both.
J Am Coll Cardiol. 1999;33:499–505.
31.
Lehtimaki T,
Lehtinen S, Solakivi T, Nikkilä M, Jaakkola O, Jokela H,
Ylä-Herttuala S, Luoma JS, Koivula T, Nikkari T. Autoantibodies
against oxidized low density lipoprotein in patients with
angiographically verified coronary artery disease.
Arterioscler Thromb Vasc Biol. 1999;19:23–27.
32.
Freigang S,
Hörkkö S, Miller E, Witztum JL, Palinski W. Immunization of LDL
receptor–deficient mice with homologous malondialdehyde-modified and
native LDL reduces progression of atherosclerosis by
mechanisms other than the induction of high titers of antibodies to
oxidative neoepitopes. Arterioscler Thromb
Vasc Biol. 1998;18:1972–1982.
33. Cyrus T, Witztum JL, Rader D, Tangirala RK, Fazio S, Linton MF, Funk CD. Disruption of the 12/15-lipoxygenase gene diminishes atherosclerosis in apo E-deficient mice. J Clin Invest. 1999;103:1597–1604.[Medline] [Order article via Infotrieve]
34. Liao F, Andalibi A, Qiao JH, Allayee H, Fogelman AM, Lusis AJ. Genetic evidence for a common pathway mediating oxidative stress, inflammatory gene induction, and aortic fatty streak formation in mice. J Clin Invest. 1994;94:877–884.
35.
Staprans I, Rapp
JH, Pan XM, Hardman DA, Feingold KR. Oxidized lipids in the diet
accelerate the development of fatty streaks in
cholesterol-fed rabbits.
Arterioscler Thromb Vasc Biol. 1996;16:533–538.
36.
Staprans I, Pan
XM, Rapp JH, Feingold KR. Oxidized cholesterol in the diet
accelerates the development of aortic atherosclerosis
in cholesterol-fed rabbits.
Arterioscler Thromb Vasc Biol. 1998;18:977–983.
37.
Staprans I, Pan
XM, Rapp JH, Grunfeld C, Feingold KR. Oxidized cholesterol
in the diet accelerates the development of
atherosclerosis in LDL receptor- and apolipoprotein
E-deficient mice. Arterioscler Thromb Vasc
Biol. 2000;20:708–714.
38.
Palinski W,
Koschinsky T, Butler S, Miller E, Silvestre M, Vlassara H, Cerami A,
Witztum JL. Immunological evidence for the presence of advanced
glycosylation end products in atherosclerotic lesions of
euglycemic rabbits.
Arterioscler Thromb Vasc Biol. 1995;15:571–582.
39. Harland WA, Gilbert JD, Brooks CJ. Lipids of human atheroma, 8: oxidised derivatives of cholesteryl linoleate. Biochim Biophys Acta. 1973;316:378–385.[Medline] [Order article via Infotrieve]
40.
Kapadia SR, Nissen
SE, Ziada KM, Guetta V, Crowe TD, Hobbs RE, Starling RC, Young JB,
Tuzcu EM. Development of transplantation vasculopathy and progression
of donor-transmitted atherosclerosis: comparison by
serial intravascular ultrasound imaging.
Circulation. 1998;98:2672–2678.
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