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According to Swedish National Board of Health and Welfare statistics, a dramatic decrease in both the incidence of and mortality from acute myo-cardial infarction has been seen in the past two deca...

Objectives. A common nonsynonymous single nucleotide polymorphism (SNP) in the CD93 gene (rs3746731, Pro541Ser) has been associated with risk of coronary artery disease (CAD). CD93 is a transmembrane glycoprotein, which is detectable in soluble form in human plasma. We investigated whether the concentration of soluble CD93 in plasma is related to risk of myocardial infarction (MI) and CAD, using a case-control study of premature MI (n = 764) and a nested case-control analysis of a longitudinal cohort study of 60-year-old subjects (analysis comprising 844 of 4232 subjects enrolled at baseline). In addition, SNPs in the CD93 gene were studied in relation to plasma CD93 concentration and CD93 mRNA expression. Methods and Results. A sensitive and specific enzyme-linked immunosorbent assay was established for determination of the plasma CD93 concentration. Subjects were divided into three groups according to tertiles of the distribution of CD93 concentration. Lower odds ratios for risk of MI and incidence of CAD were observed in the middle CD93 tertile (142-173 mu g L(-1)): odds ratio (95% confidence interval), 0.69 (0.49-0.97) and 0.61 (0.40-0.94), respectively. These associations were independent of traditional CAD risk factors. The minor allele of a SNP in the 3' untranslated region of CD93(rs2749812) was associated with increased plasma CD93 concentrations (P = 0.03) and increased CD93 mRNA expression levels (P = 0.02). Conclusion. The results of the present study suggest that the concentration of soluble CD93 in plasma is a potential novel biomarker for CAD, including MI.

The aim was to study the stimuli responsible for triggering and sustaining the plasma concentration of the inflammatory marker interleukin-6 (IL-6) in patients with a first myocardial infarction before the age of 60 and healthy control subjects matched for age and sex. The plasma IL-6 concentration, antibodies against Chlamydia pneumoniae, cytomegalovirus, Epstein-Barr virus, Helicobacter pylori, herpes simplex type 1 and 2, and genotype for the IL6-174 GC single-nucleotide polymorphism were determined 3 months after the acute event. The results showed that patients had higher IL-6 levels than control subjects, whereas there were no differences regarding individual or total number (pathogen burden) of positive antibody tests against the different pathogens or IL6 genotype distribution. The plasma IL-6 concentration was associated with the number of positive antibody tests in patients and control subjects, whereas patients irrespective of IL6 genotype had increased IL-6. Multivariate analysis, including traditional coronary heart disease risk factors, antibodies against pathogens, and IL6 genotype, explained 17% of the variation of the plasma IL-6 concentration. Neither pathogen burden nor IL6 genotype did contribute to the variation of plasma IL-6 levels, whereas smoking, body-mass index, hypertension, case-control status, and age were determinants of the plasma IL-6 concentration.

Atherothrombotic disease in the coronary arteries leads to myocardial infarction (MI) through plaque rupture or erosion of the endothelium, the former mechanism predominating in men and the latter in women. Inflammation is a key feature of these processes, and the interplay between inflammation and matrix metalloproteinases (MMPs) in this context is not fully understood. In this study, we investigated the association between inflammatory markers and MMPs in men and women.Blood samples were drawn 3 months after a first MI in 387 patients and 387 sex- and age-matched controls (82% men). C-reactive protein (CRP), interleukin-6 (IL-6), IL-8, -18, tumour necrosis factor-alpha (TNF-alpha), macrophage chemoattractant protein-1 (MCP-1), MMP-1, -3 and -9 were measured. Coronary angiography was performed in 243 of the patients, and they were classified into 0-, 1-, 2- or 3-vessel disease groups.CRP, IL-6, -8, -18 and TNF-alpha were higher, and MMP-3 and -9 were lower, in patients than in controls. A greater proportion of women (49%) had 0-vessel disease than men (16%, p0.0001). A gender specific pattern of associations between inflammatory markers and MMPs was found as IL-6 (r(S)=0.29, p0.05), IL-18 (r(S)=0.34, p0.01) and MCP-1 (r(S)=0.35, p0.01) correlated with MMP-3 in female patients, whereas CRP (r(S)=0.23, p0.0001), IL-6 (r(S)=0.13, p0.05) and IL-8 (r(S)=-0.21, p0.01) correlated with MMP-9 in male patients.The present study demonstrates different patterns of association between inflammatory markers and MMPs in men and women, strengthening the hypothesis of gender specific differences in pathophysiological mechanisms of MI.

Background: Interleukin (JL)-I² plays a central role in inflammation and atherosclerosis, but levels of IL-1I², its natural antagonist, IL-1Ra, and their balance in human atherosclerotic lesions, a ...

Aims We examined whether antibodies against peptides 45 and 210 of apoB-100 are related to myocardial infarction (MI) and severity of coronary atherosclerosis. Methods and results Three hundred and eighty-seven survivors of a first MI (aged

BACKGROUND AND AIM: Enhanced and prolonged postprandial lipaemia is associated with coronary heart disease (CHD). However, the mechanisms linking postprandial lipaemia to the increased risk of atherosclerosis and CHD remain to be determined. The aim of the present study was to examine the effects of a high-fat meal on plasma levels of the pro-inflammatory cytokine interleukin-6 (IL-6) and cellular adhesion molecules in CHD patients and control subjects. METHODS AND RESULTS: Forty-one middle-aged men with premature CHD and 26 healthy male controls were investigated. The plasma triglyceride response to the high-fat meal was significantly greater among cases than controls. The oral fat load induced a twofold increase in plasma concentrations of IL-6, an increase that was similar in CHD patients and control subjects. No changes could be detected in plasma concentrations of cellular adhesion molecules in response to postprandial lipaemia in either CHD patients or control subjects. CONCLUSION: The results of the present study suggest that a high-fat meal affects mechanisms that induce increased inflammatory activity, which is recognised as a key modulator in the development of atherosclerosis and CHD. However, the increased levels of plasma IL-6 appear not to be determined by the magnitude of the postprandial triglyceridaemia.

Objectives. The importance of matrix metalloproteinases (MMPs) in the progression and rupture of the atherosclerotic plaque is gaining increasing recognition but the mechanisms are not yet fully understood. The aim of this study was to investigate the significance of MMP-3 in the acute phase of myocardial infarction (MI) and the influence of the −1612 5A/6A MMP-3 gene promoter polymorphism on serum MMP-3 concentration. Subjects. One-hundred and sixty-four patients admitted with ST-elevation MI and receiving thrombolysis treatment were included in this study. Serum MMP-3 was analysed at admission, after 48 h and at 3 months. Results. Serum MMP-3 concentration was significantly increased at 3 months when compared with admission and 48 h (19.5 ng mL−1 [14.4–24.7] vs. 15.5 ng mL−1 [10.5–21.8] at admission, P

Myocardial infarction (MI) is commonly caused by atherosclerotic plaque rupture following excessive degradation of collagen fibers in the atherosclerotic lesion. We investigated whether interindividual variability in risk of MI was related to polymorphisms in the gene encoding matrix metalloproteinase (MMP)-1, a key fibrillar collagen–degrading enzyme. Several single nucleotide polymorphisms in the MMP1 gene promoter were identified following sequencing DNA samples from 30 individuals. An analysis of the polymorphisms in a cohort of British whites with coronary atherosclerosis, including 639 patients with MI and 538 non-MI subjects, revealed a haplotype effect of the −519A>G and −340T>C polymorphisms on risk of MI, with the A −519 -C −340 and G −519 -T −340 haplotypes being protective (odds ratio=0.70 [0.57 to 0.86]; P =0.0007), whereas the G −519 -C −340 haplotype increased MI risk (odds ratio=1.94 [1.15 to 3.28]; P =0.013). This finding was replicated in a subsequent analysis of 387 Swedish MI patients and 387 healthy controls (odds ratio=0.70 [0.55 to 0.89], P =0.003, for A −519 -C −340 and G −519 -T −340 ; odds ratio=1.54 [0.97 to 2.46], P =0.07, for G −519 -C −340 ). In vitro assays showed that compared with the A −519 -T −340 haplotype, the A −519 -C −340 and G −519 -T −340 haplotypes had lower promoter activity, whereas the G −519 -C −340 haplotype had greater promoter strength, in driving gene expression in human macrophages. Haplotype-specific differences in MMP1 mRNA level in atherosclerotic tissues were also detected. The data indicate that MMP1 gene variation is a genetic factor contributing to interindividual differences in MI risk.

SummaryFibrinogen has consistently been recognized as an independent predictor of myocardial infarction (MI). Multiple mechanisms link fibrinogen to MI; therefore disentangling the factors underlying variation in plasma fibrinogen concentration is essential. Candidate regions in the fibrinogen gamma (FGG), alpha (FGA) and beta (FGB) genes were screened for single nucleotide polymorphisms (SNPs). Several novel SNPs were detected in the FGG and FGA genes in addition to the previously known SNPs in the fibrinogen genes. Tight linkage disequilibrium extending over various physical distances was observed between most SNPs. Consequently, eight SNPs were chosen and determined in 377 postinfarction patients and 387 healthy individuals. None of the SNPs were associated with plasma fibrinogen concentration or MI. Haplotype analyses revealed a consistent pattern of hap-lotypes associated with variation in risk of MI. Of the four haplo-types inferred using the FGA –58G> A and FGG 1299+79T> C SNPs, the most frequent haplotype, FGG-FGA*1 (prevalence 46.6%), was associated with increased risk of MI (OR 1.51; 95%CI 1.18, 1.93), whereas the least frequent haplotype, FGGFGA*4 (11.8%), was associated with lower risk of MI (OR 0.79 95%CI 0.64, 0.98). In conclusion, fibrinogen haplotypes, but not SNPs in isolation, are associated with variation in risk of MI.

Background —Exaggerated postprandial triglyceridemia is common in normolipidemic patients with coronary artery disease (CAD). Alterations in the composition of triglyceride-rich lipoproteins (TRLs) are likely to underlie this metabolic disturbance. However, the composition of very-low-density lipoproteins (VLDLs), which are the most abundant postprandial TRLs, has never been defined in CAD patients. Methods and Results —We examined postprandial changes in the number and composition of VLDLs in middle-aged, normolipidemic CAD patients and control subjects. TRLs from 14 patients and 14 control subjects aged 45 to 55 years were subfractionated by density gradient ultracentrifugation into Svedberg flotation rate (Sf) fractions >400, 60 to 400, and 20 to 60. The VLDLs were separated from chylomicron remnants by immunoaffinity chromatography. In CAD patients, the postprandial concentrations of triglycerides and large (Sf 60 to 400) VLDL particles were elevated. In addition, their postprandial large VLDLs were enriched in apolipoprotein (apo) C-I and their postprandial small (Sf 20 to 60) VLDL remnants were enriched with apo C-I and cholesterol. Conclusions —Perturbed handling of postprandial triglycerides in normolipidemic CAD patients involves the accumulation of apo C-I–rich large VLDL particles and the generation of small, apo C-I– and cholesterol-rich VLDL remnants.

We examined the relationships of serum 25-hydroxyvitamin D (25(OH)D) concentration to established and emerging cardiovascular risk factors and risk of myocardial infarction (MI) in a population-based case-control study of MI before the age of 60 years.A total of 387 survivors of a first MI and 387 sex- and age-matched controls were included. Fasting blood samples drawn three months after the MI in cases and at the same time in the matched controls were used for biochemical analyses.Serum concentrations of 25(OH)D, adjusted for seasonal variation, were lower in cases than controls (55.0 (40.0-71.0) nmol/L vs 60.5 (47.0-75.0) nmol/L; median (interquartile range); standardized odds ratio (OR) for MI with 95% confidence interval in univariable analysis: 0.80 (0.69-0.93); p = 0.003). The 25(OH)D association with MI disappeared after adjustment for established and emerging risk factors (OR: 1.01 (0.82-1.25)). Current smoking and plasma levels of proinsulin and PAI-1 activity were independently associated with 25(OH)D in controls, whereas waist circumference, plasma triglycerides, proinsulin, PAI-1 activity and cystatin C, and non-Nordic ethnicity were independently associated with 25(OH)D in patients. Serial measurements of 25(OH)D (samples drawn4 h and 3 months after the onset of MI) in 57 patients showed no systematic differences between sampling times.Vitamin D insufficiency, which is associated with a multitude of metabolic, procoagulant and inflammatory perturbations, is not independently related to premature MI. This suggests that vitamin D insufficiency either constitutes an epiphenomenon or increases the risk of MI by promoting established risk factor mechanisms that predispose to atherothrombosis.

Background The TNFSF4/TNFRSF4 system, along with several other receptor-ligand pairs, is involved in the recruitment and activation of T-cells and is therefore tentatively implicated in atherosclerosis and acute coronary syndromes. We have previously shown that genetic variants in TNFSF4 are associated with myocardial infarction (MI) in women. This prompted functional studies of TNFSF4 expression. Methods and Results Based on a screening of the TNFSF4 genomic region, a promoter polymorphism (rs45454293) and a haplotype were identified, conceivably involved in gene regulation. The rs45454293T-allele, in agreement with the linked rs3850641G-allele, proved to be associated with increased risk of MI in women. Haplotype-specific chromatin immunoprecipitation of activated polymerase II, as a measure of transcriptional activity in vivo, suggested that the haplotype including the rs45454293 and rs3850641 polymorphisms is functionally important, the rs45454293T- and rs3850641G-alleles being associated with lower transcriptional activity in cells heterozygous for both polymorphisms. The functional role of rs45454293 on transcriptional levels of TNFSF4 was clarified by luciferase reporter assays, where the rs45454293T-allele decreased gene expression when compared with the rs45454293C-allele, while the rs3850641 SNP did not have any effect on TNFSF4 promoter activity. Electromobility shift assay showed that the rs45454293 polymorphism, but not rs3850641, affects the binding of nuclear factors, thus suggesting that the lower transcriptional activity is attributed to binding of one or more transcriptional repressor(s) to the T-allele. Conclusions Our data indicate that the TNFSF4 rs45454293T-allele is associated with lower TNFSF4 expression and increased risk of MI.

Interleukin (IL)-beta plays a central role in inflammation and atherosclerosis, but levels of IL-1beta, its natural antagonist, IL-1Ra, and their balance in human atherosclerotic lesions, are unknown. Knowledge of protein levels in atherosclerosis and the influence of a functional IL-1Ra polymorphism would increase the understanding of atherosclerosis pathogenesis.Fresh and endotoxin-stimulated explanted human atherosclerotic and normal arteries were analyzed for IL-1beta, IL-1Ra and IL-1 receptor 1 (IL-1R1) using TaqMan PCR and enzyme-linked immunosorbent assay. Two hundred forty-three survivors of a first myocardial infarction were genotyped for a polymorphism in IL-1Ra and their coronary atherosclerosis analyzed by using coronary angiography. Levels of IL-1beta, IL-1Ra and IL-1R1 mRNA were significantly increased in atherosclerotic arteries compared with normal arteries. Endotoxin stimulation increased IL-1beta levels more than IL-1Ra levels (ie, promoted a pro-inflammatory state). A polymorphism in IL-1Ra known to increase levels of IL-1Ra was associated with decreased mean coronary artery plaque area.Activation of innate immunity changed the balance between IL-1beta and IL-1Ra in atherosclerotic arteries towards a more pro-inflammatory state. In line with this, the presence of an IL-1Ra intron 2 polymorphism known to increase IL-1Ra levels, and possibly the IL-1Ra:IL-1beta ratio, was associated with reduced coronary atherosclerosis.

Environmental exposures filtered through the genetic make-up of each individual alter the transcriptional repertoire in organs central to metabolic homeostasis, thereby affecting arterial lipid accumulation, inflammation, and the development of coronary artery disease (CAD). The primary aim of the Stockholm Atherosclerosis Gene Expression (STAGE) study was to determine whether there are functionally associated genes (rather than individual genes) important for CAD development. To this end, two-way clustering was used on 278 transcriptional profiles of liver, skeletal muscle, and visceral fat (n = 66/tissue) and atherosclerotic and unaffected arterial wall (n = 40/tissue) isolated from CAD patients during coronary artery bypass surgery. The first step, across all mRNA signals (n = 15,042/12,621 RefSeqs/genes) in each tissue, resulted in a total of 60 tissue clusters (n = 3958 genes). In the second step (performed within tissue clusters), one atherosclerotic lesion (n = 49/48) and one visceral fat (n = 59) cluster segregated the patients into two groups that differed in the extent of coronary stenosis (P = 0.008 and P = 0.00015). The associations of these clusters with coronary atherosclerosis were validated by analyzing carotid atherosclerosis expression profiles. Remarkably, in one cluster (n = 55/54) relating to carotid stenosis (P = 0.04), 27 genes in the two clusters relating to coronary stenosis were confirmed (n = 16/17, P, Author Summary The WHO predicts that coronary artery disease (CAD) will become the leading cause of death worldwide in 2010. Currently, major research efforts are focused on understanding the genetics of CAD through multi-center, genome-wide association studies of tens of thousands of patients and controls. Such studies can identify common variants of general importance throughout the entire population, which are likely relatively few. The number of rare genetic variants and variants that act in the context of environmental risk factors for CAD is probably much higher. We performed whole-genome expression analyses in several organs to identify functionally associated genes important for CAD development. We found an atherosclerosis module (A-module) consisting of 128 genes, enriched with genetic risk for CAD, involving transendothelial migration of leukocytes (TEML) and LIM domain binding 2 (LDB2) as its high-hierarchy regulator. Our study design represents a novel way of understanding the molecular underpinnings of CAD, focusing on genome-wide expression sensing both environmental and genetic influences. Investigating the relative enrichment of genetic CAD risk in functional groups (modules and networks) is an alternative approach to extract additional relevant information from genome-wide association studies. The A-module and LDB2 are attractive targets for treatments to modulate TEML and atherosclerosis development.

Summary. Background: Fibrinogen γ′, a fibrinogen γ-chain variant generated via alternative mRNA processing, has been associated with susceptibility to thrombotic disease. Objective: The present case–control study searched for potential determinants of the plasma fibrinogen γ′ concentration and examined the relationship between this variant and risk of myocardial infarction (MI). Patients and methods: The Stockholm Coronary Artery Risk Factor study, comprising 387 postinfarction patients and 387 healthy individuals, was employed. The fibrinogen gamma (FGG) 9340T > C [rs1049636], fibrinogen alpha (FGA) 2224G > A [rs2070011] and fibrinogen beta (FGB) 1038G > A [rs1800791] polymorphisms were determined. The plasma fibrinogen γ′ concentration was measured by enzyme-linked immunosorbent assay. The multifactor dimensionality reduction method was used for interaction analyses on risk of MI. Results: The FGG 9340T > C and FGA 2224G > A polymorphisms, total plasma concentrations of fibrinogen, insulin and high-density lipoprotein, and gender appeared to be independent determinants of plasma fibrinogen γ′ concentration in patients, and the corresponding determinants in controls included FGG 9340T > C and FGA 2224G > A polymorphisms and plasma fibrinogen concentration. An elevated plasma fibrinogen γ′ concentration proved to be an independent predictor of MI [adjusted odds ratio (OR) (95% CI): 1.24 (1.01, 1.52)]. The plasma fibrinogen γ′ concentration was involved in a high-order interaction with total plasma fibrinogen and the FGG 9340T > C and FGA 2224G > A polymorphisms, associated with a further increased risk of MI [OR (95% CI): 3.22 (2.35, 4.39)]. Conclusions: Plasma fibrinogen γ′ concentration influences the risk of MI, and this relationship seems to be strengthened by the presence of an elevated total plasma fibrinogen concentration and the FGG 9340T and FGA 2224G alleles.

Objectives. Matrix metalloproteinase-3 (MMP-3) is implicated in the formation of atherosclerotic plaques, and the MMP-3 −1612 5A/6A polymorphism is associated with myocardial infarction (MI) and stable coronary artery disease (CAD). The present study examined whether the −1612 5A/6A polymorphism in the promoter region of the MMP-3 gene influences serum concentrations of MMP-3 and whether serum concentrations of MMP-3 are related to extent of coronary atherosclerosis and risk of MI. Design and subjects. This case–control study was conducted in three hospitals in the northern part of Stockholm. A total of 755 MI patients aged below 60 were screened, 433 entered and 387 completed the study. Three hundred and eighty-seven sex- and age-matched control subjects were recruited from the general population of the same county. Methods. The MMP-3 genotype was determined by PyrosequencingTM and the serum MMP-3 concentration was quantified with an immunoassay. Severity and extension of CAD was assessed by quantitative coronary angiography in a subgroup of patients (n = 243). Results. Patients had lower serum MMP-3 concentration than controls. There was a strong association between MMP-3 −1612 5A/6A genotype and serum concentrations of MMP-3. The presence of one or two copies of the 6A-allele was associated with a graded increase in serum MMP-3. In female patients there was an inverse correlation (r = −0.39, P

Aim Interleukin-18 (IL-18) is a pro-inflammatory cytokine with a central role in the inflammatory cascade. In the present study, we investigated whether patients with precocious myocardial infarction have higher plasma IL-18 concentrations than matched controls. Furthermore, the relationships between plasma IL-18 concentrations and coronary atherosclerosis, C-reactive protein (CRP), interleukin-6 (IL-6) and traditional cardiovascular risk factors were examined. Methods and results Three hundred eighty-seven unselected survivors of a first myocardial infarction aged less than 60 years and 387 sex and age matched controls were enrolled in the study. A subset of patients ( n =236) was evaluated by quantitative coronary angiography. Postinfarction patients had significantly higher mean level of plasma IL-18 than controls (309.6±138.6 versus 285.4±115.7pg IL-18/mL). Furthermore, plasma IL-18 concentration was significantly associated with coronary plaque area ( r =0.17, p =0.009). This relationship remained in a partial correlation analysis adjusting for CRP ( r =0.15, p =0.02), for IL-6 ( r =0.15, p =0.02) and for both CRP and IL-6 ( r =0.15, p =0.02). In addition, IL-18 levels were significantly associated with other cardiovascular risk factors, namely age, low density lipoprotein (LDL) cholesterol, triglycerides, high density lipoprotein (HDL) cholesterol, insulin, proinsulin, body mass index (BMI), systolic and diastolic blood pressure. Conclusion The present work provides evidence that plasma IL-18 is increased in postinfarction patients and is associated with coronary atherosclerosis.

Objective. Enhanced expression of CXCL16 has been demonstrated in atherosclerotic plaques and several properties have been attributed to CXCL16 that could influence the atherosclerotic process. CXCL16 exists in transmembrane and soluble forms. The transmembrane form acts as a scavenger receptor for oxidised LDL whereas the soluble form acts a chemoattractant for mainly CD8+ T cells. In addition, the soluble form of CXCL16 influences human aortic smooth muscle cell proliferation in vitro. In the present work, a human molecular genetic approach employing a common polymorphism within exon 4 of CXCL16 (181 Ala>Val) was used to investigate whether CXCL16 may be involved in the development of coronary artery disease. The polymorphism is located within the spacer region between the chemokine and transmembrane region and potentially influences an Ala/Val cleavage site, a site commonly used for the release of chemokines by tumour necrosis factor-α converting enzyme. Design and subjects. We first genotyped 387 unselected survivors of a first myocardial infarction aged V polymorphism was detected. However, the V-allele was associated with increased severity of coronary stenoses. Secondly, the V-allele was associated with smaller minimal luminal diameter in the coronary segment subjected to intervention in a second cohort of patients undergoing PTCA with stent implantation. Conclusions. The present work provides evidence that CXCL16 is involved in processes leading to enhanced stenosis in atherosclerotic coronary arteries.

Ath1 is a quantitative trait locus on mouse chromosome 1 that renders C57BL/6 mice susceptible and C3H/He mice resistant to diet-induced atherosclerosis. The quantitative trait locus region encompasses 11 known genes, including Tnfsf4 (also called Ox40l or Cd134l), which encodes OX40 ligand. Here we report that mice with targeted mutations of Tnfsf4 had significantly (P

A previous study revealed that the difference in susceptibility to atherosclerotic lesions between inbred mouse strains SM/J and NZB/BlNJ was determined by one major locus (Ath8). In this study a (SM/J x NZB/BlNJ) F(1) x SM/J backcross localized Ath8 by quantitative trait locus mapping to chromosome 4 with a suggestive LOD score of 2.7. This quantitative trait locus (QTL) was confirmed using an (SM/J x NZB/BlNJ) intercross; Ath8 mapped to a 23cM region with a significant LOD score of 3.6. The genes for toll-like receptor 4 (T1r4), arachidonic acid epoxygenase (Cyp2j5), and angiopoietin-like protein 3 (Angptl3) map to this region. These candidate genes were analyzed for expression and sequence differences in the mouse and for associations with cardiovascular traits in human. Sequence analysis of Angptl3 shows a base pair substitution in SM, the susceptible strain, giving rise to an amino acid change in the fibrinogen homology domain of the protein. We found a significant association between ANGPTL3 and atherosclerotic lesions (P0.05) in human. These results suggest that Angptl3 is involved in atherosclerosis susceptibility in both mouse and human.

Objective— Overexpression of elastolytic cysteine and aspartic proteases, known as cathepsins, is implicated in atherogenesis. The potential significance of imbalance in expression between cathepsins and their inhibitor cystatin C in cardiovascular disease has been highlighted by the demonstration of cystatin C deficiency in human atherosclerosis and abdominal aortic aneurysms. Methods and Results— We identified and characterized physiologically relevant polymorphisms in the promoter region of the cystatin C gene that influence cystatin C production and used these polymorphisms as a tool to examine the significance of cystatin C in coronary atherosclerosis in vivo in humans. Seven polymorphisms, all in strong-linkage disequilibrium, were identified in the cystatin C gene, of which 2 promoter polymorphisms (−82G/C and −78T/G) were functional in vitro in electromobility shift and transient transfection assays. Genotyping of 1105 individuals (237 survivors of a first myocardial infarction before age 60 and 2 independent groups comprising a total of 868 healthy individuals) revealed that the plasma cystatin C concentration was significantly lower in carriers of the mutant haplotype. Furthermore, the mutant haplotype was associated with a higher average number of stenoses per coronary artery segment in unselected postinfarction patients (N=237) undergoing routine coronary angiography. Conclusions— These results provide human evidence for an important role of cystatin C in coronary artery disease.

All-trans retinoic acid, controlled by cytochrome P450, family 26 (CYP26) enzymes, potentially has beneficial effects in atherosclerosis treatment. This study investigates CYP26 subfamily B, polypeptide 1 (CYP26B1) in atherosclerosis and the effects of a genetic polymorphism in CYP26B1 on retinoid catabolism. We found that CYP26B1 mRNA was induced by retinoic acid in human atherosclerotic arteries, and CYP26B1 and the macrophage marker CD68 were colocalized in human atherosclerotic lesions. In mice, Cyp26B1 mRNA was higher in atherosclerotic arteries than in normal arteries. Databases were queried for nonsynonymous CYP26B1 single nucleotide polymorphisms (SNPs) and rs2241057 selected for further studies. Constructs of the CYP26B1 variants were created and used for production of purified proteins and transfection of macrophagelike cells. The minor variant catabolized retinoic acid with significantly higher efficiency, indicating that rs2241057 is functional and suggesting reduced retinoid availability in tissues with the minor variant. rs2241057 was investigated in a Stockholm Coronary Atherosclerosis Risk Factor (SCARF) subgroup. The minor allele was associated with slightly larger lesions, as determined by angiography. In summary, this study identifies the first CYP26B1 polymorphism that alters CYP26B1 capacity to metabolize retinoic acid. CYP26B1 was expressed in macrophage-rich areas of human atherosclerotic lesions, induced by retinoic acid and increased in murine atherosclerosis. Taken together, the results indicate that CYP26B1 capacity is genetically regulated and suggest that local CYP26B1 activity may influence atherosclerosis.