© 2000 American Heart Association, Inc.
Atherosclerosis and Lipoproteins |
Stromelysin-1 and Interleukin-6 Gene Promoter Polymorphisms Are Determinants of Asymptomatic Carotid Artery Atherosclerosis
From Kuopio Research Institute of Exercise Medicine and the Department of Physiology, University of Kuopio (Finland) (R.R., S.B.V., I.M.P., J.T.); the Department of Clinical Physiology and Nuclear Medicine (R.R.) and the Department of Clinical Chemistry (S.B.V., I.M.P.), Kuopio University Hospital, Kuopio, Finland; the Centre for Cardiovascular Genetics, Department of Medicine, UCLMS, The Rayne Institute (L.-A.L., S.E.H.), London, UK; the Department of Prevention, Rehabilitation, and Sports Medicine, Freiburg University Hospital (A.S.-T.), Freiburg, Germany; and Pennington Biomedical Research Center, Louisiana State University (C.B.), Baton Rouge.
Correspondence to Prof Rainer Rauramaa, Kuopio Research Institute of Exercise Medicine, Haapaniementie 16, FIN-70100 Kuopio, Finland. E-mail rainer.rauramaa{at}messi.uku.fi
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
Abstract—The functional 5A/6A polymorphism of the stromelysin-1 promoter has been implicated as a potential genetic marker for the progression of angiographically determined atherosclerosis in patients with coronary artery disease. Recently, a novel interleukin-6 (IL-6) gene functional G/C polymorphism at -174 in the promoter has also been reported. In this study, we analyzed the relation of these two polymorphisms with carotid artery atherosclerosis in 109 randomly selected, middle-aged men without exercise-induced ischemia. Atherosclerosis was quantified as intima-media thickness (IMT) by high-resolution ultrasonography. Univariately, stromelysin genotype was significantly (P=0.015) associated with IMT, and this relation remained (P=0.033) after adjustments for age, cardiorespiratory fitness, body mass index, smoking, LDL cholesterol, and systolic blood pressure and for sonographers. The 5A/6A polymorphism independently explained 7% of the variance in carotid bifurcation IMT. The IL-6 polymorphism was also significantly associated (P=0.036) with increased IMT, with men homozygous for the G allele having IMT that was 11% greater than men homozygous for the C allele. Men who were homozygous for both the 6A and G alleles had an covariate adjusted IMT that was 36% greater than men who were homozygous for neither allele (P<0.003). These data suggest that genetic factors that predispose to reduced matrix remodeling (stromelysin 6A allele) and to increased inflammation (IL-6 G allele) combine to increase susceptibility for intima-media thickening in the carotid bifurcation, a predilection site for atherosclerosis.
Key Words: stromelysin-1 • interleukin-6 • DNA polymorphism • B-mode ultrasonography • carotid atherosclerosis • population sample
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Vascular remodeling is an essential phenomenon in the development of atherosclerotic changes in the arterial wall. Matrix metalloproteinases and their endogenous tissue inhibitors (eg, tissue inhibitor of metalloproteinase-1) regulate the accumulation of extracellular matrix during tissue injury and thus the growth of the atherosclerotic plaque.1 2 Stromelysin-1 is a key member of the matrix metalloproteinase family and has a wide substrate specificity.3 Stromelysin expression is regulated primarily at the level of transcription, where the promoter of the gene responds to different stimuli including growth factors and cytokines.4
Recently, a common variant in the promoter sequence of the stromelysin-1 gene has been reported.5 The polymorphism is located 600 bp upstream from the start of transcription in which 1 allele has a run of 6 adenosines (6A), whereas the other has only 5 (5A). In vitro studies of promoter strength showed that the 5A allele expressed higher activity than the 6A allele in both cultured fibroblasts and vascular smooth muscle cells,6 and band shift assays showed that a nuclear protein bound more strongly to the 6A than the 5A sequence, suggesting that this protein may be a repressor of transcriptional activity. This suggests that compared with other genotypes, individuals homozygous for the 6A allele would have lower stromelysin levels in the arterial wall because of reduced gene transcription, and this lower level of proteolytic activity might therefore favor deposition of extracellular matrix. This would lead to a more rapid development and progression of an atherosclerotic plaque. In support of this, the 6A allele has been implicated as a potential genetic marker for the progression of angiographically determined atherosclerosis in patients with coronary artery disease.5 7 8
Interleukin-6 (IL-6) is a cytokine derived from diverse tissues including fibroblasts, monocytes, adipocytes, and endothelial cells.9 10 It plays a key role in driving the acute inflammatory response and orchestrates the production of acute phase proteins such as C-reactive protein.9 IL-6 has been associated with several markers of endothelial dysfunction such as chemokine and adhesion molecule release.10 In this respect, it may play a direct role through the induction of endothelial activation11 or an indirect role through the stimulation of fibrinogen synthesis,12 which may itself be directly pathogenic. IL-6 may thus be pivotal in the putative inflammatory pathogenesis of coronary disease. Inflammatory markers are associated with the development of coronary disease, with disease severity,13 and with the occurrence of coronary events.14 Data from the Physicians Health Study suggest that this association is still present after an 8-year follow-up period,15 implying that progression of atheroma may also be associated with raised inflammatory markers. Unstable angina is associated with activation of systemic circulating neutrophils16 and with elevated inflammatory markers such as C-reactive protein and IL-6 levels.17 18 19 The magnitude of this elevation predicts poor outcome and is not merely secondary to the presence of myocardial necrosis or ischemia.20
We have recently detected a functional polymorphism 174 bp upstream from the start of transcription of the IL-6 gene.21 The polymorphism is common, with the frequency of the C allele being 0.41 in a group of 944 healthy men from the United Kingdom. Using constructs of the 5' flanking region of the IL-6 gene in a luciferase reporter vector transiently transfected into HeLa cells, the C construct showed 62% lower expression than the G construct at baseline. However, after stimulation with lipopolysaccharides (LPS) or IL-1, expression from the C construct was not significantly increased, whereas expression from the G construct increased to 235% and 360%, respectively, compared with the unstimulated level. Thus, the G allele appears to be associated with a significant increase in IL-6 response to inflammatory stimuli, at least in vitro. As would be expected from this result, in vivo, individuals with the genotype GG have the highest mean IL-6 levels and CC individuals the lowest.21 There is no evidence that IL-6 has a direct effect on stromelysin gene expression, but the upregulation of tissue inhibitor of metalloproteinase-1 synthesis by IL-6 may shift the balance in favor of matrix protein deposition, leading to atherothrombosis and the progression of coronary artery disease.22 23 Thus, an IL-6 genotype that determines plasma IL-6 levels may have an indirect effect on the vascular wall through this mechanism.
The aim of this study was thus to investigate the combined roles of the 5A/6A polymorphism of the stromelysin-1 promoter and of the G-174C polymorphism of the IL-6 promoter in ultrasonographically quantified carotid artery atherosclerosis in a randomly selected sample of asymptomatic, middle-aged men without exercise-induced ischemia.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Study Sample
The study sample has been described in detail earlier.24 25 Essentially, we examined a random sample of 50- to 60-year-old Finnish men living in the Kuopio area. Of the 212 participants, 110 subjects were asymptomatic and showed no exercise-induced ischemia in the ECG. Because of missing data on carotid artery ultrasonography or genotype analyses or covariates, complete data were available for 87 men. The study protocol was approved by the Ethics Committee of Kuopio University.
Carotid Ultrasonography
Carotid artery atherosclerosis was determined by
measuring the mean maximum intima-media thickness (IMT)26
of the far walls of the carotid artery bifurcations, that is, the
distance between the end of the distal common carotid and the tip of
the flow diver. The ultrasound device was equipped with a
high-resolution, 10-MHz annular array transducer providing 0.25-mm
axial resolution (Biosound Phase 2). Two certified sonographers
performed the ultrasound scanning from the anterior oblique, lateral,
and posterior oblique views by using standardized and pretested
protocols.27 The calibration of the ultrasound unit was
routinely checked with the use of an RMI 414B tissue phantom. The
examination was recorded on half-inch videotape (Panasonic 7330
SVHS). A sonographer chose from the videotape up to 5 images for
digitization (Studio DC10 Plus frame grabber). The measurement of IMT
was based on a new automated edge detection software, based on an
active contour model, also called snake.28 29 Essentially,
the snake adapts itself to the intima-media layer by a dynamic
energy-minimization process. This process uses a combination of
gray-level gradient intensity, spatial correlation, and/or certain
knowledge-based criteria. It incorporates the assessment of edges by
combining the initial estimation, desired edge properties, continuity
and the curvature of a contour, and some other constraints into a
single dynamic process. This process was tuned by adapting the
elasticity and rigidity of the snake to the contour characteristics of
the intimal and adventitial layers. This design is appropriate for both
intimal and adventitial layer tracking. If noises are present in
the subintimal region (this could happen often in thick
arterial walls or in the region of the carotid
bifurcation), the snake might be trapped by them. To avoid this, the
cost values are memorized while passing the subintimal region and a
limited subadventitial region. Together with the assumption that the
adventitial layer should have the maximum mean gradient value in this
region, the snake can detect the optimum shape for the adventitia.
A certified sonographer performed the measurement of IMT along segments of the far walls of the carotid bifurcation up to the level of the flow divider. Every pixel along the traced regions served as a measurement point (pixel size, 0.0058 mm). The traced regions were as long as both layers could be detected by the active contour program so that on the average, 413 measurement points were performed at each measurement site. The measurement results and the tracing lines were stored and could be reloaded, together with the image for visual control of the tracing lines. The capability for manual correction was not installed to avoid a reduction in the precision of the IMT measurements by manual outlining. Instead, a cut function for incorrectly traced sections was established to exclude them from analysis.
Exercise ECG and Cardiorespiratory Fitness
The detailed description of the cardiopulmonary exercise
stress test has been published elsewhere.25 The ECG was
continuously monitored and recorded every minute during exercise
and up to 7 minutes after exercise with standard and Mason-Likar leads.
ST-segment change 80 ms after the QRS complex was assessed
automatically to the nearest 0.01 mV at the highest ergometer work load
(Case 12, Marquette Electronics, Inc). The ischemic waveform
potential was classified as the 8% to 11% cumulative frequency of
ST-segment changes in each ECG lead in the study population, including
all subjects who underwent the exercise stress test. For the assessment
of the greatest ECG signal amplitude (ie, ST-segment change) with
equally spaced lead vectors, leads V1 and aVR
were not used. Spatial distribution of ischemia was classified
by combining any ischemic waveform potential in leads
V2 through V6 (cutoff
limits for the ST change: increase of 0.04, V2,
to decrease of up to 0.18 mV, V5), leads I
through III (decrease of 0.04 mV, lead I, up to 0.2 mV, leads II
through III), and leads aVL or aVF (decrease of 0.04 and 0.18 mV).
Subjects were classified into the ischemic group by any
ischemic waveform potential. The nonischemic group
consisted of no ST-segment potential changes in the respective ECG
leads. Subjects with either left (n=1) or right (n=4) bundle-branch
block, ventricular bigeminy (n=1), trigeminy (n=1), or
ventricular tachycardia (n=1), which are known
to affect lead vectors, and 1 subject with abnormally positioned
isoelectric level were excluded from the ST-segment
analyses.
The method for assessing cardiorespiratory fitness has been described elsewhere.30 An exercise physiologist defined aerobic threshold visually as the first nonlinear increase of ventilation by means of breath-by-breath respiratory gas analyses during the exercise test.
DNA Analyses
Genomic DNA was isolated from white blood cells by digestion
with proteinase K and SDS followed by the phenol/chloroform extraction
procedure and dialysis.31 Genotyping for the stromelysin
and IL-6 promoter polymorphisms was carried out as
described.7 21
Other Methods
Venous blood samples were drawn, without stasis, between 7:30
and 10:00 AM after a 12-hour fast and 30 minutes of rest in
a supine position. Serum IL-6 concentrations were analyzed with
the Pelikine compact human IL-6 ELISA kit with the Pelikine tool set
(Central Laboratory of the Netherlands Red Cross Blood Transfusion
Service, Amsterdam) and stromelysin by the Biotrak Matrix
metalloproteinase-3 human ELISA system (Amersham International plc).
The methodology for the lipoprotein cholesterol assays has
been described earlier.24 Blood pressure was measured with
a random zero device with a cuff size of 52x14 cm, as described
previously.24 Smoking habits were evaluated by asking the
subject the number of cigarettes smoked daily. Waist-to-hip ratio was
defined as the ratio of waist girth at the umbilicus to the hip girth,
measured at the trochanteric level.
Statistical Methods
Conformance of the allele frequencies to Hardy-Weinberg
equilibrium proportions were tested by use of a
2 test.32 Serum levels of
stromelysin and IL-6 were nonnormally distributed. Although logarithmic
transformation could be used for stromelysin analysis, the
relatively high number of IL-6 concentrations below the detection limit
did not normalize the distribution after square root transformation.
Therefore, the median levels and approximate standard deviations have
been presented. ANCOVA (general linear model) with Bonferroni
correction was used to test the relation of the polymorphisms to
IMT. Statistical analyses were performed with SPSS for Windows
software package version 9.0.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
The characteristics of the men are shown in Table 1
and did not differ by
genotype. For both polymorphisms, the distribution of
genotypes was in Hardy-Weinberg equilibrium. The frequency of
the stromelysin 6A allele 0.58 (95% CI, 0.51 to 0.65) and of the
IL-6 G allele was 0.44 (95% CI, 0.37 to 0.60). As shown in Table 2, the stromelysin-1 genotype was
significantly (P=0.015) associated with IMT, with the
heterozygotes having 16% lower IMT compared with other men.
Univariately, the stromelysin genotype explained
6.7% of the variance in IMT. The association remained
(P=0.033) after adjustments for age, cardiorespiratory
fitness, body mass index, smoking, LDL cholesterol, and
systolic blood pressure and for the sonographer, with the whole
adjusted model explaining 13% of the variation in IMT. The IL-6
polymorphism was significantly (P=0.036) associated with
IMT univariately but no more after covariate adjustment
(Table 2). The IL-6 genotype was neither
associated with plasma levels of lipoproteins, IL-6, fibrinogen, or
plasminogen activator inhibitor-1,
although for the latter three, levels were moderately lower in the CC
compared with the GG men (data not shown). There were no differences in
the distribution of plaques within the genotypes separately or
combined. Serum concentrations of stromelysin or IL-6 differed between
genotypes neither separately nor combined (Table 2). No
correlation was found between serum stromelysin or IL-6 and IMT.
|
|
To test whether there were additive effects of these two gene variants
on IMT, genotypes for the 5A/6A and G/C polymorphisms were
combined in 4 groups as follows: (1) no homozygotes for the alleles
associated with the high IMT: 5A5A or 5A6A and CC or CG (n=53), (2)
5A5A or 5A6A and GG (n=9), (3) 6A6A and CC or CG (n=17), and (4)
homozygotes for both alleles associated with the high IMT: 6A6A and
GG (n=8). As shown in the Figure, the
combined genotype at both loci was significantly associated
with IMT (P=0.003), with the IMT of the group 4 differing
from that of groups 1 (P=0.003), 2 (P=0.021), and
3 (P=0.004). The combined genotype explained 11% of
the variance in IMT. This relation remained significant
(P=0.004) after adjustments for age, cardiorespiratory
fitness, body mass index, smoking, LDL cholesterol, and
systolic blood pressure and for the sonographers, with the
whole adjusted model accounting for 24% of the variance in IMT.
|
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
The novel finding of this study is the demonstration of the additive effects of the 5A/6A and G/C promoter polymorphisms of the stromelysin-1 and in the IL-6 and genes, respectively, on asymptomatic atherosclerosis in the carotid bifurcation, a predilection site for the development of the disease.33
Stromelysin-1 is a key regulator of matrix remodeling,34 35 36 and in situations of atherosclerotic development in which extracellular matrix deposition is occurring, individuals who are genetically predisposed to produce less stromelysin-1 would have a lower ability to remodel and degrade the matrix components. In vitro, the 6A allele shows lower promoter activity than the 5A allele,6 and assuming this pattern of transcription also holds in vivo, individuals with 1 or more 6A alleles in the cells within a developing carotid atherosclerotic lesion would be capable of producing less stromelysin-1 mRNA and hence would have a lower enzyme activity. This would result in faster plaque growth and would be seen with carotid ultrasound as a greater IMT. In this sample, there was no difference in stromelysin levels between subjects with different 5A/6A genotypes. This lack of association may be explained in part by the small sample size but may also reflect that serum stromelysin levels will be determined by secretion of stromelysin from many cell types and cells located at a number of different sites within the body, and serum levels may therefore not show a strong association with stromelysin levels within the atherosclerotic plaque or vessel wall.
In vitro, the G allele of the IL-6 gene has roughly twice the promoter strength, at least in situations of inflammatory stress such as in the presence of IL-1 and LPS.21 Whereas in vivo the G allele has been associated with higher plasma levels of IL-6,21 the present data failed to show such a relation, although IL-6 levels showed the expected trend of being highest in GG subjects and lower in those with 1 or more C allele. The lack of a statistically significant effect may be explained by the relatively small sample size studied here. Immunohistochemistry of the human arterial atherosclerotic wall has shown IL-6 mRNA expression localized to cellular and extracellular deposits in the connective tissue matrix, with the fibrous plaque having statistically significantly higher level of IL-6 than the intima and media.37 Studies in apoE knockout mice that develop atherosclerotic plaques in the aorta also show that elevated levels of IL-6 mRNA predominate in the plaque area compared with normal mice.38 Thus, IL-6 may damage the endothelium and lead to the initiation of atherosclerosis, especially in areas of the vascular system that are predisposed to atherosclerosis because of decreased shear stress with turbulent blood flow such as the carotid bifurcation.
High-resolution B-mode ultrasonography together with the sophisticated
automated analyzing software enabled us to detect early changes in the
arterial intima-media layer of the carotid bifurcation. The
subjects were asymptomatic healthy men randomly selected
from the general population, but the present results agree with
recent findings on the stromelysin-1 gene and the progression of
atherosclerosis in patients with established
atherosclerotic coronary artery disease5 on the
progression of angiographically determined coronary
atherosclerosis in men after coronary bypass
surgery7 and in subjects with coronary artery
disease.8 Subjects with the 6A6A genotype and less
advanced arterial narrowing in coronary angiography
showed more rapid disease progression compared with those already
having advanced atherosclerosis. Moreover, in patients
whose lipid levels were lowered and who had less progression of
disease, the stromelysin-1 genotype was not associated with
differences in progression, whereas in those whose lipid levels
remained high, the 5A allele was associated with low progression
and the 6A allele with high progression of angiographic
stenosis. There is now evidence to support the view that
besides having a major lipid-lowering effect, statins also have an
anti-inflammatory effect,39 probably acting through
modulation of NF-
-B activity.40 41 Thus, part of the
reduced influence of the stromelysin genotype on disease
progression in treated patients may be through this mechanism. Although
there are few data available about the biological and clinical
associations of the IL-6 G/C polymorphism, no data are available on
healthy asymptomatic subjects. In a small study,
preliminary data have been obtained that the GG genotype was
associated with increased risk of myocardial infarction at a young age
(<45 years), whereas the CC genotype was
protective.42 Moreover, the C allele was associated
with lower levels of markers of endothelial damage such
as E-selectin.43 The association observed in the
present study of greater IMT in healthy men with the
genotype GG is supportive of these findings.
The clinical relevance of the 5A/6A and G/C polymorphisms is further emphasized by the high population frequency of the 6A and G alleles, with 29% of subjects in this sample being 6A6A homozygotes, 22% being GG homozygotes, and 10% being homozygous for both. From a population point of view, it is also relevant to note that the frequency of the 6A "risk-predisposing" allele is significantly higher in these healthy men from eastern Finland, a geographic area with a high prevalence of atherosclerotic cardiovascular diseases,44 than reported5 in healthy men from the United Kingdom, where the risk of coronary heart disease is lower (frequency for the 6A allele 0.55 versus 0.48, P<0.05). By contrast, the frequency of the "high-risk" G allele in these Finnish men is significantly lower than reported in the United Kingdom (0.44 versus 0.59, P=0.01).
The present results show for the first time the combined contribution of genetic variation in the genes coding for a key cytokine of the inflammatory processes and for a matrix metalloproteinase in the evolution of asymptomatic atherosclerosis, as assessed noninvasively by the measurement of arterial wall thickening in a randomly selected population sample. Homozygotes for both the G and 6A alleles, who, based on their allele frequency should represent roughly 10% of the Finnish population, appear to be predisposed to arterial wall thickening compared with other genotypes. The present data are potentially valuable for the primary prevention, and together with recent observations on patients with advanced atherosclerosis,5 6 7 8 should help in identifying individuals with inherited high risk for coronary heart disease. Given the strength of the present findings, it is important that studies be undertaken in different ethnic populations to confirm these observations.
|
Acknowledgments |
|---|
This study was supported by grants from the Ministry of Education in Finland (322/722/94; 80/722/95; 176/722/96; 42/722/97; 84/722/98), from the City of Kuopio, from the Academy of Finland (68103), from the Juho Vainio foundation, from CERIN (Center de Recherche et ‘Information Nutritionnelles de Paris, France), from FRSQ (Fonds de la Recherche en Santé du Québec), and by the British Heart Foundation (PG007 and 86-77), the Commission of the European Communities (HIFMECH study, contract BMH4-CT96-0272).
Received July 26, 1999; accepted July 10, 2000.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Woessner JF. Matrix metalloproteinases and their inhibitors in connective tissue remodeling. FASEB J. 1991;5:2145–2154.[Abstract]
2. Newby AC, Southgate KM, Davies M. Extracellular matrix degrading metalloproteinases in the pathogenesis of arteriosclerosis. Basic Res Cardiol. 1994;89(suppl 1):59–70.
3. Gomis-Rüth FX, Maskos K, Betz M, Bergner A, Huber R, Suzuki K, Yoshida N, Nagase H, Brew K, Bourenkov GP, Bartunik H, Bode W. Mechanism of inhibition of the human matrix metalloproteinase stromelysin-1 by TIMP-1. Nature. 1997;389:77–81.[Medline] [Order article via Infotrieve]
4.
Diaz-Meco MT, Quinones S, Municio MM, Sanz L, Bernal
D, Cabrero E, Saus J, Moscat J. Protein kinase C-independent expression
of stromelysin by platelet-derived growth factor, ras oncogene, and
phosphatidylcholine-hydrolyzing phospholipase C. J Biol
Chem. 1991;266:22597–22602.
5.
Ye S, Watts GF, Mandalia S, Humphries SE, Henney AM.
Preliminary report: genetic variation in the human stromelysin promoter
is associated with progression of coronary
atherosclerosis. Br Heart J. 1995;73:209–215.
6.
Ye S, Eriksson P, Hamsten A, Kurkinen M, Humphries SE,
Henney AM. Progression of coronary
atherosclerosis is associated with a common genetic
variant of the human stromelysin-1 promoter which results in reduced
gene expression. J Biol Chem. 1996;271:13055–13060.
7. Humphries SE, Luong LA, Talmud PJ, Frick MH, Kesäniemi YA, Pasternack A, Taskinen MR, Syvänne M. The 5A/6A polymorphism in the promoter of the stromelysin-1 (matrix metalloproteinase-3) gene predicts progression of angiographically determined coronary artery disease in men in the LOCAT gemfibrozil study: Lopid Coronary Angiography Trial. Atherosclerosis. 1998;139:49–56.[Medline] [Order article via Infotrieve]
8. de Maat MP, Jukema JW, Ye S, Zwinderman AH, Moghaddam PH, Beekman M, Kastelein JJ, van Boven AJ, Bruschke AV, Humphries SE, Kluft C, Henney AM. Efficacy of pravastatin treatment in coronary atherosclerosis is modulated by natural variation in the stromelysin-1 promoter. Am J Cardiol. 1999;83:852–856.[Medline] [Order article via Infotrieve]
9. Heinrich PC, Castell JV, Andus T. Interleukin-6 and the acute phase response. Biochem J. 1990;265:621–636.[Medline] [Order article via Infotrieve]
10.
Yudkin JS, Stehouwre CDA, Emeis JJ, Coppack SW. The
insulin resistance syndrome and endothelial dysfunction
as common consequences of cytokines originating from adipose
tissue: a new paradigm for insulin resistance and
cardiovascular risk. Arterioscler Thromb Vasc
Biol. 1999;19:972–978.
11. Romano M, Sironi M, Toniatti C, Polentarutti N, Fruscella P, Ghezzi P, Faggioni R, Luini W, van Hinsbergh V, Sozzani S, Bussolino F, Poli V, Ciliberto G, Montovani A. Role of IL-6 and its soluble receptor in induction of chemokines and leukocyte recruitment. Immunity. 1997;6:1–20.[Medline] [Order article via Infotrieve]
12.
Dalmon J, Laurent M, Courtois G. The human beta
fibrinogen promoter contains a hepatocyte nuclear factor
1-dependent interleukin-6-responsive element. Mol Cell Biol. 1993;13:1183–1193.
13. Heinrich J, Schulte H, Schönfeld R, Köhler E, Assmann G. Association of variables of coagulation, fibrinolysis and acute-phase with atherosclerosis in coronary and peripheral arteries and those arteries supplying the brain. Thromb Haemost. 1995;73:374–379.[Medline] [Order article via Infotrieve]
14. Mori T, Sasaki J, Kawaguchi H, Handa K, Takada Y, Matsunaga A, Kono S, Aakawa K. Serum glycoproteins and severity of coronary atherosclerosis. Am Heart J. 1995;129:234–238.[Medline] [Order article via Infotrieve]
15.
Ridker PM, Cushman M, Stampfer MJ, Tracy RP, Hennekens
CH. Inflammation, aspirin, and the risk of
cardiovascular disease in apparently healthy men.
N Engl J Med. 1997;336:973–979.
16.
Kohchi K, Takebayashi S, Hiroki T, Nbuyoshi M.
Significance of adventitial inflammation of the coronary artery
in patients with unstable angina: results at autopsy.
Circulation. 1985;71:709–716.
17. Berk BC, Weintraub WS, Alexander RW. Elevation of C-reactive protein in active coronary artery disease. Am J Cardiol. 1990;65:168–172.[Medline] [Order article via Infotrieve]
18.
Biasucci LM, Vitelli A, Liuzzo G, Altamura S, Caligiuri
G, Monaco C, Rebuzzi AG, Ciliberto G, Maseri A. Elevated levels of
interleukin-6 in unstable angina. Circulation. 1996;94:874–877.
19.
Liuzzo G, Biasucci LM, Rebuzzi AG, Gallimore JR,
Caligiuri G, Lanza GA, Quaranta G, Monaco C, Pepys MB, Maseri A. Plasma
protein acute-phase response in unstable angina is not induced by
ischemic injury. Circulation. 1996;94:2373–2380.
20. Haverkate F, Thompson SG, Pyke SD, Gallimore JR, Pepys MB. Production of C-reactive protein and risk of coronary events in stable and unstable angina: European Concerted Action on Thrombosis and Disabilities Angina Pectoris Study Group. Lancet. 1997;349:462–466.[Medline] [Order article via Infotrieve]
21. Fishman D, Faulds G, Jeffery R, Mohamed-Ali V, Yudkin JS, Humphries S, Wo P. The effect of novel polymorphisms in the interleukin-6 (IL-6) gene: their effect on IL-6 transcription and plasma IL-6 levels, and an association with systemic-onset juvenile chronic arthritis. J Clin Invest. 1998;102:1369–1376.[Medline] [Order article via Infotrieve]
22. Kordula T, Güttgemann I, Rose-John S, Roeb E, Osthues A, Tschesche H, Koj A, Heinrich PC, Graeve L. Synthesis of tissue inhibitor of metalloproteinase-1 (TIMP-1) in human hepatoma cells (HepG2): up-regulation by interleukin-6 and transforming growth factor beta 1. FEBS Lett. 1992;313:143–147.[Medline] [Order article via Infotrieve]
23. Roeb E, Graeve L, Müllberg J, Matern S, Rose-John S. TIMP-1 protein expression is stimulated by IL-1 beta and IL-6 in primary rat hepatocytes. Ann N Y Acad Sci. 1995;762:462–464.[Medline] [Order article via Infotrieve]
24.
Rauramaa R, Väisänen S, Mercuri M, Rankinen
T, Penttilä I, Bond MG. Association of risk factors and body iron
status to carotid atherosclerosis in middle-aged
eastern Finnish men. Eur Heart J. 1994;15:1020–1027.
25. Rauramaa R, Rankinen T, Tuomainen P, Väisänen S, Mercuri M. Inverse relationship between cardiorespiratory fitness and carotid atherosclerosis. Atherosclerosis. 1995;112:213–221.[Medline] [Order article via Infotrieve]
26.
Pignoli P, Tremoli E, Poli A, Oreste P, Poletti R.
Intimal plus medial thickness of the arterial wall: a
direct measurement with ultrasound imaging. Circulation. 1986;74:1399–1406.
27. Mercuri M, Bond MG, Sirtori CR, Veglia F, Crepaldi G, Feruglio FS, Descovich G, Ricci G, Rubba P, Mancini M, Gallus G, Bianchi G, D’Alò G, Ventura A. Pravastatin reduces carotid intima-media thickness progression in an asymptomatic hypercholesterolemic Mediterranean population: the Carotid Atherosclerosis Italian Ultrasound Study. Am J Med. 1996;101:627–634.[Medline] [Order article via Infotrieve]
28. Kass M, Witkin A, Trzopoulos D. Snakes: active contour models. Int J Comp Vision. 1987;321–331.
29. Ceng D, Schmidt-Trücksäss A, Cheng K, Sandrock M, Burckhardt H. Automatic Detection of the Intimal and the Adventitial Layers of the Common Carotid Artery Wall in Ultrasound B-Mode Images Using Snakes. Werner B, ed. Los Alamitos, Calif: IEEE Computer Society; International Conference on Image Analysis and Processing. 1999:452–457.
30. Rauramaa R, Tuomainen P, Väisänen S, Rankinen T. Physical activity and health-related fitness in middle-aged men. Med Sci Sports Exerc. 1995;27:707–712.[Medline] [Order article via Infotrieve]
31. Molecular Cloning: A Laboratory Manual. Sambrook J, Fritsch EF, Maniatis T, eds. New York, NY: Cold Spring Harbor Laboratory Press; 1989:9.16–9.19.
32. Weir BS. Genetic Data Analysis: Methods for Discrete Population Genetic Data. Sunderland, Mass: Sinauer Associates, Inc, Publishers; 1990.
33. Glagov S, Zarins C, Giddens DP, Ku DN. Hemodynamics and atherosclerosis: insights and perspectives gained from studies of human arteries. Arch Pathol Lab Med. 1988;112:1018–1031.[Medline] [Order article via Infotrieve]
34.
Schönbeck U, Mach F, Sukhova GK, Murphy C,
Bonnefoy JY, Fabunmi RP, Libby P. Regulation of matrix
metalloproteinase expression in human vascular smooth muscle cells by T
lymphocytes: a role for CD40 signaling in plaque rupture? Circ
Res. 1997;81:448–454.
35.
Mach F, Schönbeck U, Bonnefoy JY, Pober JS, Libby
P. Activation of monocyte/macrophage functions related to acute
atheroma complication by ligation of CD40: induction of
collagenase, stromelysin, and tissue factor.
Circulation. 1997;96:396–399.
36. Carty CS, Soloway PD, Kayastha S, Bauer J, Marsan B, Ricotta JJ, Dyjski M. Nicotine and cotinine stimulate secretion of basic fibroblast growth factor and affect expression of matrix metalloproteinases in cultured human smooth muscle cells. J Vasc Surg. 1996;24:927–934.[Medline] [Order article via Infotrieve]
37. Rus HG, Vlaicu R, Niculescu F. Interleukin-6 and interleukin-8 protein and gene expression in human arterial atherosclerotic wall. Atherosclerosis. 1996;127:263–271.[Medline] [Order article via Infotrieve]
38.
Sukovich DA, Kauser K, Shirley FD, Del Vecchio V,
Halks-Miller M, Rubanyi GM. Expression of interleukin-6 in
atherosclerotic lesions of male ApoE-knockout mice: inhibition by
17ß-estradiol. Arterioscler Thromb Vasc Biol. 1998;18:1498–1505.
39.
Ridker PM, Rifai N, Pfeffer MA, Sacks FM, Moye LA,
Goldman S, Flaker GC, Baunwald E. Inflammation,
pravastatin, and the risk of coronary events after
myocardial infarction in patients with average cholesterol
levels: Cholesterol and Recurrent Events (CARE)
Investigators. Circulation. 1998;98:839–844.
40.
Bustos C, Hernández-Presa MA, Ortego M,
Tuñón J, Ortega L, Pérez F, Díaz C,
Hernández G, Eido J. HMG-CoA reductase inhibition by atorvastatin
reduces neointimal inflammation in a rabbit model of
atherosclerosis. J Am Coll Cardiol. 1998;32:2057–2064.
41.
Guijarro C, Kim Y, Schoonover CM, Massy ZA, O’Donnell
MP, Kasiske BL, Keane WF, Kashtan CE. Lovastatin inhibits
lipopolysaccharide-induced NF-kappaB activation in human
mesangial cells. Nephrol Dial Transplant. 1996;11:990–996.
42. Humphries SE, Luong L-A, Montgomery HE, Day INM, Mohamed-Ali V, Yudkin JS. Gene-environment interaction in the determination of levels of plasma fibrinogen. Thromb Haemost.. 1999;82:818–825.[Medline] [Order article via Infotrieve]
43. Luong LA, Faulds G, Montgomery HE, Mohamed-Ali V, Fishman D, Woo P, Miller GJ, Yudkin JS, Humphries S. Variation in the gene for interleukin-6 (IL-6) and inflammatory markers in healthy subjects. Blood Coagul Fibrinolysis. 1999;10:S99–S100.
44.
Salomaa V, Miettinen H, Kuulasmaa K, Niemelä M,
Ketonen M, Vuorenmaa T, Lehto S, Palomäki P, Mähönen
M, Immonen-Räihä P, Arstila M, Kaarsalo E, Mustaniemi H,
Torppa J, Tuomilehto J, Puska P, Pyörälä K. Decline
of coronary heart disease mortality in Finland during 1983 to
1992: roles of incidence, recurrence, and case-fatality: the
FINMONICA MI Register Study. Circulation. 1996;94:3130–3137.
This article has been cited by other articles:
 |
|
 |
|
  M. Cozzolino, M. L. Biondi, A. Galassi, O. Turri, D. Brancaccio, and M. Gallieni Matrix metalloproteinase-1 and matrix metalloproteinase-3 gene promoter polymorphisms are associated with mortality in haemodialysis patients Nephrol. Dial. Transplant., July 1, 2009; 24(7): 2207 - 2212. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y.-C. Liao, H.-F. Lin, T. Rundek, R. Cheng, Y.-C. Guo, R. L. Sacco, and S.-H. H. Juo Segment-Specific Genetic Effects on Carotid Intima-Media Thickness: The Northern Manhattan Study Stroke, December 1, 2008; 39(12): 3159 - 3165. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Armstrong, S. Abilleira, M. Sitzer, H. S. Markus, and S. Bevan Polymorphisms in MMP Family and TIMP Genes and Carotid Artery Intima-Media Thickness Stroke, November 1, 2007; 38(11): 2895 - 2899. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. R. Tso, J. G. Merino, and S. Warach Interleukin-6 174G/C Polymorphism and Ischemic Stroke: A Systematic Review Stroke, November 1, 2007; 38(11): 3070 - 3075. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. J. White, S. J. Duffy, A. S. Walton, J. F. Ng, G. E. Rice, S. Mukherjee, J. A. Shaw, G. L. Jennings, A. M. Dart, and B. A. Kingwell Matrix metalloproteinase-3 and coronary remodelling: Implications for unstable coronary disease Cardiovasc Res, September 1, 2007; 75(4): 813 - 820. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. C. Barber, L.-Y. E. Chang, B. D. Arnoldo, G. F. Purdue, J. L. Hunt, J. W. Horton, and C. C. Aragaki Innate Immunity SNPs are Associated with Risk for Severe Sepsis after Burn Injury Clin. Med. Res., December 1, 2006; 4(4): 250 - 255. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Abilleira, S. Bevan, and H. S Markus The role of genetic variants of matrix metalloproteinases in coronary and carotid atherosclerosis J. Med. Genet., December 1, 2006; 43(12): 897 - 901. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Yamada, N. Metoki, H. Yoshida, K. Satoh, S. Ichihara, K. Kato, T. Kameyama, K. Yokoi, H. Matsuo, T. Segawa, et al. Genetic Risk for Ischemic and Hemorrhagic Stroke Arterioscler Thromb Vasc Biol, August 1, 2006; 26(8): 1920 - 1925. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Liu, Y. Berthier-Schaad, M. D. Fallin, N. E. Fink, R. P. Tracy, M. J. Klag, M. W. Smith, and J. Coresh IL-6 Haplotypes, Inflammation, and Risk for Cardiovascular Disease in a Multiethnic Dialysis Cohort J. Am. Soc. Nephrol., March 1, 2006; 17(3): 863 - 870. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Ye Influence of matrix metalloproteinase genotype on cardiovascular disease susceptibility and outcome Cardiovasc Res, February 15, 2006; 69(3): 636 - 645. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M Libra, S S Signorelli, Y Bevelacqua, P M Navolanic, V Bevelacqua, J Polesel, R Talamini, F Stivala, M C Mazzarino, and G Malaponte Analysis of G(-174)C IL-6 polymorphism and plasma concentrations of inflammatory markers in patients with type 2 diabetes and peripheral arterial disease J. Clin. Pathol., February 1, 2006; 59(2): 211 - 215. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. M. Mayosi, P. J. Avery, M. Baker, N. Gaukrodger, H. Imrie, F. R. Green, M. Farrall, H. Watkins, and B. Keavney Genotype at the -174G/C Polymorphism of the Interleukin-6 Gene Is Associated With Common Carotid Artery Intimal-Medial Thickness: Family Study and Meta-Analysis Stroke, October 1, 2005; 36(10): 2215 - 2219. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Weger, I. Steinbrugger, A. Haas, W. Marz, Y. El-Shabrawi, W. Weger, O. Schmut, and W. Renner Role of the Interleukin-6 -174 G>C Gene Polymorphism in Retinal Artery Occlusion Stroke, February 1, 2005; 36(2): 249 - 252. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Bennermo, C. Held, S. Stemme, C.-G. Ericsson, A. Silveira, F. Green, and P. Tornvall Genetic Predisposition of the Interleukin-6 Response to Inflammation: Implications for a Variety of Major Diseases? Clin. Chem., November 1, 2004; 50(11): 2136 - 2140. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. A. Manolio, E. Boerwinkle, C. J. O'Donnell, and A. F. Wilson Genetics of Ultrasonographic Carotid Atherosclerosis Arterioscler Thromb Vasc Biol, September 1, 2004; 24(9): 1567 - 1577. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. H. Gibbons, C. C. Liew, M. O. Goodarzi, J. I. Rotter, W. A. Hsueh, H. M. Siragy, R. Pratt, and V. J. Dzau Genetic Markers: Progress and Potential for Cardiovascular Disease Circulation, June 29, 2004; 109(25_suppl_1): IV-47 - IV-58. [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Murase, Y. Yamada, A. Hirashiki, S. Ichihara, H. Kanda, M. Watarai, F. Takatsu, T. Murohara, and M. Yokota Genetic risk and gene-environment interaction in coronary artery spasm in Japanese men and women Eur. Heart J., June 1, 2004; 25(11): 970 - 977. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Hirashiki, Y. Yamada, Y. Murase, Y. Suzuki, H. Kataoka, Y. Morimoto, T. Tajika, T. Murohara, and M. Yokota Association of gene polymorphisms with coronary artery disease in low- or high-risk subjects defined by conventional risk factors J. Am. Coll. Cardiol., October 15, 2003; 42(8): 1429 - 1437. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. M.L. Chapman, J. P. Beilby, S. E. Humphries, L. J. Palmer, P. L. Thompson, and J. Hung Association of an allelic variant of interleukin-6 with subclinical carotid atherosclerosis in an Australian community population Eur. Heart J., August 2, 2003; 24(16): 1494 - 1499. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Acalovschi, T. Wiest, M. Hartmann, M. Farahmi, U. Mansmann, G. U. Auffarth, A. J. Grau, F. R. Green, C. Grond-Ginsbach, and M. Schwaninger Multiple Levels of Regulation of the Interleukin-6 System in Stroke Stroke, August 1, 2003; 34(8): 1864 - 1869. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Beyzade, S. Zhang, Y.-k. Wong, I. N. M. Day, P. Eriksson, and S. Ye Influences of matrix metalloproteinase-3 gene variation on extent of coronary atherosclerosis and risk of myocardial infarction J. Am. Coll. Cardiol., June 18, 2003; 41(12): 2130 - 2137. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. L. Medley, B. A. Kingwell, C. D. Gatzka, P. Pillay, and T. J. Cole Matrix Metalloproteinase-3 Genotype Contributes to Age-Related Aortic Stiffening Through Modulation of Gene and Protein Expression Circ. Res., June 13, 2003; 92(11): 1254 - 1261. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Pola, A. Flex, E. Gaetani, R. Flore, M. Serricchio, and P. Pola Synergistic Effect of -174 G/C Polymorphism of the Interleukin-6 Gene Promoter and 469 E/K Polymorphism of the Intercellular Adhesion Molecule-1 Gene in Italian Patients With History of Ischemic Stroke Stroke, April 1, 2003; 34(4): 881 - 885. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. H. Von der Thusen, J. Kuiper, T. J. C. Van Berkel, and E. A. L. Biessen Interleukins in Atherosclerosis: Molecular Pathways and Therapeutic Potential Pharmacol. Rev., March 1, 2003; 55(1): 133 - 166. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Jerrard-Dunne, H. S. Markus, D. A. Steckel, A. Buehler, S. von Kegler, and M. Sitzer Early Carotid Atherosclerosis and Family History of Vascular Disease: Specific Effects on Arterial Sites Have Implications for Genetic Studies Arterioscler Thromb Vasc Biol, February 1, 2003; 23(2): 302 - 306. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Yamada, H. Izawa, S. Ichihara, F. Takatsu, H. Ishihara, H. Hirayama, T. Sone, M. Tanaka, and M. Yokota Prediction of the Risk of Myocardial Infarction from Polymorphisms in Candidate Genes N. Engl. J. Med., December 12, 2002; 347(24): 1916 - 1923. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. S. Athan, J. H. Lee, A. Arriaga, R. P. Mayeux, and B. Tycko Polymorphisms in the Promoter of the Human APP Gene: Functional Evaluation and Allele Frequencies in Alzheimer Disease Arch Neurol, November 1, 2002; 59(11): 1793 - 1799. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Ghilardi, M. L. Biondi, M. DeMonti, O. Turri, E. Guagnellini, and R. Scorza Matrix Metalloproteinase-1 and Matrix Metalloproteinase-3 Gene Promoter Polymorphisms Are Associated With Carotid Artery Stenosis Stroke, October 1, 2002; 33(10): 2408 - 2412. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Kiechl, E. Lorenz, M. Reindl, C. J. Wiedermann, F. Oberhollenzer, E. Bonora, J. Willeit, and D. A. Schwartz Toll-like Receptor 4 Polymorphisms and Atherogenesis N. Engl. J. Med., July 18, 2002; 347(3): 185 - 192. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. Loftus and M. Thompson The role of matrix metalloproteinases in vascular disease Vascular Medicine, May 1, 2002; 7(2): 117 - 133. [Abstract] [PDF]
|
|
|
|
|
|
J. L. Hunt, R. Fairman, M. E. Mitchell, J. P. Carpenter, M. Golden, T. Khalapyan, M. Wolfe, D. Neschis, R. Milner, B. Scoll, et al. Bone Formation in Carotid Plaques: A Clinicopathological Study Stroke, May 1, 2002; 33(5): 1214 - 1219. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Rundek, M. S. Elkind, J. Pittman, B. Boden-Albala, S. Martin, S. E. Humphries, S.-H. H. Juo, and R. L. Sacco Carotid Intima-Media Thickness Is Associated With Allelic Variants of Stromelysin-1, Interleukin-6, and Hepatic Lipase Genes: The Northern Manhattan Prospective Cohort Study Stroke, May 1, 2002; 33(5): 1420 - 1423. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A Vickers, F. R Green, C. Terry, B. M Mayosi, C. Julier, M. Lathrop, P. J Ratcliffe, H. C Watkins, and B. Keavney Genotype at a promoter polymorphism of the interleukin-6 gene is associated with baseline levels of plasma C-reactive protein Cardiovasc Res, March 1, 2002; 53(4): 1029 - 1034. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Bertsch, W. Zimmer, W. Casarin, C. Denz, M. Quintel, and K. Fassbender Real-Time PCR Assay with Fluorescent Hybridization Probes for Rapid Interleukin-6 Promoter (-174G{->}C) Genotyping Clin. Chem., October 1, 2001; 47(10): 1873 - 1874. [Full Text] [PDF]
|
|
|
|
|
|
B. Zhang, S. Dhillon, I. Geary, W. M. Howell, F. Iannotti, I. N.M. Day, and S. Ye Polymorphisms in Matrix Metalloproteinase-1, -3, -9, and -12 Genes in Relation to Subarachnoid Hemorrhage Stroke, September 1, 2001; 32(9): 2198 - 2202. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||