Poly(ADP-Ribose) Polymerase Activity and Coronary Artery Disease in Type 2 Diabetes Mellitus: An Observational and Bidirectional Mendelian Randomization Study.

OBJECTIVE: Experimental evidence suggests a close link between PARP (poly[ADP-ribose] polymerase) activation and diabetic endothelial dysfunction. Here, we tested whether PARP activity in circulating leukocytes was associated with coronary artery disease (CAD) among patients with type 2 diabetes mellitus (T2DM). Approach and Results: We performed observational and bidirectional Mendelian randomization studies of 3149 Chinese individuals with T2DM who underwent coronary angiography, with leukocyte PARP activity, 16 tag single-nucleotide polymorphisms in PARP1 and PARP2, and 17 CAD risk single-nucleotide polymorphisms analyzed. Of 3149 participants, 1180 who further received percutaneous coronary intervention were prospectively followed for 1 year to track major adverse cardiovascular and cerebrovascular events. Overall, greater PARP activity was cross-sectionally associated with an odds ratio of 1.23 for obstructive CAD, and prospectively with a hazard ratio of 1.34 for 1-year major adverse cardiovascular and cerebrovascular events after percutaneous coronary intervention (both P<0.001). Using a genetic score of 5 screened single-nucleotide polymorphisms in PARP1 and PARP2 as the instrumental variable, genetically predicted elevation in PARP activity showed a causal association with obstructive CAD (odds ratio=1.35, P<0.001). In contrast, the genetic risk of CAD had no significant effect on PARP activity. Ex vivo and in vitro cultures of human monocytes showed that rs747657, as the lead single-nucleotide polymorphism strongly associated with PARP activity, caused the differential binding of transcription factor GATA2 (GATA-binding protein 2) to an intronic regulatory region in PARP1, thus modulating PARP1 expression and PARP activity. CONCLUSIONS: Greater PARP activity may have causal roles in the development of obstructive CAD among patients with diabetes mellitus.

The relationship of lipoprotein-associated phospholipase A2 activity with the seriousness of coronary artery disease.

BACKGROUND: The level of lipoprotein-associated phospholipase A2 (LP-PLA2) in serum is independently correlated to coronary artery diseases (CAD). The aim of the study was to determine whether LP-PLA2 activity is positively associated with the seriousness of CAD. METHODS: Amount to 1056 patients suspected of having CAD underwent coronary angiography (CAG) to determine the seriousness of CAD. According to the amount of diseased coronary branches, the 1056 patients were split into three groups: single-vessel stenosis group, multiple-vessels stenosis group (> or = 2 diseased coronary branches),and control group (no diseased coronary branches). According to CAG results, electrocardiography, cardiac biomarker, and clinical presentation, all patients were split into four groups: acute myocardial infarction (AMI), unstable angina (UA), stable angina (SA), and control groups (excluding CAD). The activity of LP-PLA2 was compared statistically among the subgroups. Receiver operating characteristic analysis was applied to investigate the role of LP-PLA2 in evaluating the presence and seriousness of CAD. RESULTS: The level of LP-PLA2 increased in line with the number of diseased coronary branches. The levels of LP-PLA2 in the AMI and UA groups were observably higher when compared with the control and SA groups. LP-PLA2 had 75.6% sensitivity and 67.3% specificity for recognizing CAD, and 53.0% sensitivity and 80.3% specificity for recognizing severe coronary artery lesions. CONCLUSION: The activity of LP-PLA2 is positively correlated to the seriousness of CAD.

Local Matrix Metalloproteinase 9 Level Determines Early Clinical Presentation of ST-Segment-Elevation Myocardial Infarction.

OBJECTIVE: Early clinical presentation of ST-segment-elevation myocardial infarction (STEMI) and non-ST-segment-elevation myocardial infarction affects patient management. Although local inflammatory activities are involved in the onset of MI, little is known about their impact on early clinical presentation. This study aimed to investigate whether local inflammatory activities affect early clinical presentation. APPROACH AND RESULTS: This study comprised 94 and 17 patients with MI (STEMI, 69; non-STEMI, 25) and stable angina pectoris, respectively. We simultaneously investigated the culprit lesion morphologies using optical coherence tomography and inflammatory activities assessed by shedding matrix metalloproteinase 9 (MMP-9) and myeloperoxidase into the coronary circulation before and after stenting. Prevalence of plaque rupture, thin-cap fibroatheroma, and lipid arc or macrophage count was higher in patients with STEMI and non-STEMI than in those with stable angina pectoris. Red thrombus was frequently observed in STEMI compared with others. Local MMP-9 levels were significantly higher than systemic levels (systemic, 42.0 [27.9-73.2] ng/mL versus prestent local, 69.1 [32.2-152.3] ng/mL versus poststent local, 68.0 [35.6-133.3] ng/mL; P<0.01). Poststent local MMP-9 level was significantly elevated in patients with STEMI (STEMI, 109.9 [54.5-197.8] ng/mL versus non-STEMI: 52.9 [33.0-79.5] ng/mL; stable angina pectoris, 28.3 [14.2-40.0] ng/mL; P<0.01), whereas no difference was observed in the myeloperoxidase level. Poststent local MMP-9 and the presence of red thrombus are the independent determinants for STEMI in multivariate analysis. CONCLUSIONS: Local MMP-9 level could determine the early clinical presentation in patients with MI. Local inflammatory activity for atherosclerosis needs increased attention.

Matrix metalloproteinase-3 gene polymorphism (rs3025058) affects markers atherosclerosis in type 2 diabetes mellitus.

BACKGROUND: The study was designed to test the possible association between either polymorphisms of the matrix metalloproteinase-9 (MMP-9) gene (rs17576, rs3918242) or the MMP-3 5A/6A gene polymorphism (rs3025058) with markers of carotid atherosclerosis in patients with type 2 diabetes mellitus (T2DM). The second aim of the study was to demonstrate an association between either the rs17576, rs3918242 or rs3025058 and subclinical markers of coronary artery disease in the same subset of patients with T2DM. PATIENTS AND METHODS: A total of 595 subjects with T2DM and 200 subjects without T2DM (control group) were enrolled in the prospective study. Subclinical markers of carotid atherosclerosis were assessed ultrasonographically. Additionally, in a subset of subjects with T2DM a coronary computed tomography angiography (CCTA) was performed for diagnostic purposes. Genotyping of all three polymorphisms (rs17576, rs3918242, rs3025058) was performed with real-time PCR systems. RESULTS: The comparison of atherosclerosis parameters was performed with regard to different genotypes of MMP-9 rs17576, rs3918242, and MMP-3 rs3025058 polymorphisms upon enrolment and during follow-up. In our study, we found an association between the MMP-3 rs3025058 and CIMT at the time of recruitment. Multiple linear regression analysis revealed the association of either the A- allele or the A- genotypes of the rs3025058 (MMP-3) with carotid intima media thickness (CIMT) progression in a 3.8-year follow-up. We demonstrated the effect of the rs3025058 on subclinical markers of coronary atherosclerosis (coronary calcium score, number of coronary arteries with more than 50 % stenosis, and presence of at least one vessel with more than 50 % stenosis). CONCLUSIONS: We found an association between the MMP-3 rs3025058 and subclinical markers of carotid (CIMT) and coronary atherosclerosis at the time of recruitment. Moreover, we demonstrated the effect of the MMP-3 rs3025058 on CIMT progression in the 3.8-year follow-up in patients with T2DM.

Tyrosine kinase receptor B protects against coronary artery disease and promotes adult vasculature integrity by regulating Ets1-mediated VE-cadherin expression.

OBJECTIVE: Tyrosine kinase receptor B (TrkB) is a high-affinity receptor for brain-derived neurotrophic factor. In addition to its nervous system functions, TrkB is also expressed in the cardiovascular system. However, the association of TrkB and coronary artery disease (CAD) remains unknown. We investigated the role of TrkB in the development of CAD and its mechanism. APPROACH AND RESULTS: We performed a case-control study in 2 independent cohort of Chinese subjects and found -69C>G polymorphisms of TrkB gene significantly associated with CAD. TrkB -69C homozygotes, which corresponded to decreased TrkB expression by luciferase reporter assay, showed increased risk for CAD. Immunofluorescence analysis revealed that TrkB was expressed in the aortic endothelium in atherosclerotic lesions in humans and ApoE(-/-) mice. TrkB knockdown in the aortic endothelium resulted in vascular leakage in ApoE(-/-) mice. Mechanistic studies showed that TrkB regulated vascular endothelial cadherin (VE-cadherin) expression through induction and activation of Ets1 transcriptional factor. Importantly, TrkB activation attenuated proatherosclerotic factors induced-endothelial hyperpermeability in human vascular endothelial cells. CONCLUSIONS: Our data demonstrate that TrkB protects endothelial integrity during atherogenesis by promoting Ets1-mediated VE-cadherin expression and plays a previously unknown protective role in the development of CAD.

Case control feasibility study assessing the association between severity of coronary artery disease with Glutathione Peroxidase-1 (GPX-1) and GPX-1 polymorphism (Pro198Leu).

BACKGROUND: Glutathione peroxidase-1 (GPX-1) activity was reported to be useful marker for monitoring cardiovascular disease. However, accurate assessment of coronary artery disease (CAD) using GPX-1 polymorphism is limited for South Asian population. Present study aim to assess GPX-1activity and GPX-1 polymorphismin patients with coronary artery disease (CAD) who were confirmed with coronary angiography findings and in apparently healthy subjects. METHODS: Case control study was carried out with 85 patients (58 males and 27 females) 40-60 years of age confirmed as having CAD on coronary angiography findings and 85 age and sex matched healthy volunteers as controls. Blood samples were analyzed for erythrocyte GPX-1 activity and GPX-1 polymorphism in both groups and the severity of CAD was assessed using coronary angiography scoring system based on vessel, stenosis and extent score. RESULTS: Coronary angiography scores indicated that erythrocyteGPX-1 cutoff value of 23.9 U/gHb showed a high sensitivity and negative predictive value in ruling out major vessel disease. The GPX-1 Pro198Leu (CT) polymorphism was higher in patients with CAD (25.3 %) when compared to controls (10.7 %). Pro198Leu (CT) genotype showed a 2.84 fold risk for CAD [odds ratio 2.84 (95 % CI 1.15-6.98), p = 0.019]. CONCLUSION: Coronary angiography findings indicated that individuals possessing Pro198Leu (CT) polymorphism were found to be associated with low erythrocyte GPX-1 activity and increased susceptibility for CAD.

Beneficial effects of omega-3 and vitamin E coadministration on gene expression of SIRT1 and PGC1α and serum antioxidant enzymes in patients with coronary artery disease.

BACKGROUND AND AIM: SIRT1 and PGC1α are two important genes, which play critical roles in regulating oxidative stress and inflammation processes. The study aimed assess the effects of coadministration of omega-3 and vitamin E supplements on SIRT1 and PGC1α gene expression and serum levels of antioxidant enzymes in coronary artery disease (CAD) patients. METHODS AND RESULTS: Participants of this randomized controlled trial included 60 CAD male patients who were categorized into three groups: Group 1 received omega-3 (4 g/day) and vitamin E placebo (OP), group 2 omega-3 (4 g/day) and vitamin E (400 IU/day; OE), and group 3 omega-3 and vitamin E placebos (PP) for 2 months. Gene expression of SIRT1 and PGC1α in peripheral blood mononuclear cells (PBMCS) was assessed by reverse transcription polymerase chain reaction (RT-PCR). Furthermore, serum antioxidant enzyme and high-sensitivity C-reactive protein (hsCRP) levels were assessed at the beginning and end of the intervention. Gene expression of SIRT1 and PGC1α increased significantly in the OE group (P = 0.039 and P = 0.050, respectively). Catalase and hsCRP levels increased significantly in the OE and OP groups. However, glutathione peroxidase (GPX) and superoxide dismutase (SOD) levels did not statistically change in all groups. The total antioxidant capacity (TAC) increased significantly in the OE group (P = 0.009) but not in OP and PP groups. CONCLUSION: Supplementation of omega-3 fatty acids in combination with vitamin E may have beneficial effects on CAD patients by increasing gene expression of SIRT1 and PGC1α and improving oxidative stress and inflammation in these patients.

Effects of a timely therapy with doxycycline on the left ventricular remodeling according to the pre-procedural TIMI flow grade in patients with ST-elevation acute myocardial infarction.

Doxycycline has been demonstrated to reduced left ventricular (LV) remodeling, but its effect in patients with ST-elevation myocardial infarction (STEMI) and a baseline occluded [thrombolysis in myocardial infarction (TIMI) flow grade ≤1] infarct-related artery (IRA) is unknown. According to the baseline TIMI flow grade, 110 patients with a first STEMI were divided into 2 groups. Group 1: 77 patients with TIMI flow ≤1 (40 patients treated with doxycycline and 37 with standard therapy, respectively), and a Group 2: 33 patients with TIMI flow 2-3 (15 patients treated with doxycycline and 18 with standard therapy, respectively). The two randomized groups were well matched in baseline characteristics. A 2D-Echo was performed at baseline and at 6 months, together with a coronary angiography, for the remodeling and IRA patency assessment, respectively. The LV end-diastolic volume index (LVEDVi) decreased in Group 2 [-3 mL/m(2) (IQR: -12 to 4 mL/m(2))], and increased in Group 1 [6 mL/m(2) (IQR: -2 to 14 mL/m(2))], (p = 0.001). In Group 2, LVEDVi reduction was similar regardless of drug therapy, while in Group 1 the LVEDVi was smaller in patients treated with doxycycline as compared to control [3 mL/m(2) (IQR: -3 to 8 mL/m(2)) vs. 10 mL/m(2) (IQR: 1-27 mL/m(2)), p = 0.006]. A similar pattern was observed also for LV end-systolic volume and ejection fraction. In STEMI patients at higher risk, as those with a baseline TIMI flow grade ≤1, doxycycline reduces LV remodeling.

Transglutaminase 2 promotes PDGF-mediated activation of PDGFR/Akt1 and ß-catenin signaling in vascular smooth muscle cells and supports neointima formation.

BACKGROUND: Phenotypic switch of vascular smooth muscle cells (VSMCs) accompanies neointima formation and associates with vascular diseases. Platelet-derived growth factor (PDGF)-induced activation of PDGFR/Akt1 and ß-catenin signaling pathways in VSMCs has been implicated in vessel occlusion. Transglutaminase 2 (TG2) regulates these pathways and its levels are increased in the neointima. OBJECTIVE: The aim of this study was to evaluate the role of TG2 in PDGF/ß-catenin signaling cross-talk and assess its contribution to neointima. METHODS: Aortic VSMCs from wild-type and TG2 knockout mice were tested in vitro for levels of VSMC markers, proliferation, migration and PDGF-induced activation of PDGFR/Akt1 and ß-catenin pathways. Neointima in these mice was studied ex vivo in coronary vessels using a heart slice model and in vivo using a carotid artery ligation model. RESULTS: Genetic deletion of TG2 attenuated the PDGF-induced phenotypic switch of aortic VSMCs, reduced their proliferation and migration rates, and inhibited PDGF-induced activation of PDGFR/Akt1 and ß-catenin pathways in both ex vivo and in vivo neointima models. Importantly, genetic deletion of TG2 also markedly attenuated vessel occlusion. CONCLUSIONS: TG2 promotes neointima formation by mediating the PDGF-induced activation of the PDGFR/Akt1 and ß-catenin pathways in VSMCs. This study identifies TG2 as a potential therapeutic target for blocking neointima in blood vessels.

Association of PON1 and PON2 polymorphisms with PON1 activity and significant coronary stenosis in a Tunisian population.

PON1 and PON2 have attracted considerable attention as candidate genes for coronary heart disease because their enzymes function as key factors in lipoprotein catabolism pathways. We studied the distribution of PON1 and PON2 polymorphisms, including genotyping, lipid profile, and PON1 activity, and their association with PON1 activity and significant coronary stenosis (SCS) in a Tunisian population. PON1 activity was lower in patients with SCS than in controls. It increased with the R allele (QQ < QR < RR) in PON1-192 genotypes and with the L allele (MM < ML < LL) in PON1-55 genotypes. In the presence of metabolic syndrome and diabetes, PON1-192RR and PON2-311CC were associated with an increased risk of SCS and PON1-55MM seems to have lower risk. This association was evident among nonsmokers for PON1-55MM and among smokers for PON1-192RR and PON2-311CC. The GTGC haplotype seemed to increase the risk of SCS compared with the wild haplotype in a Tunisian population.

A role of matrix metalloproteinase-8 in atherosclerosis.

RATIONALE: Atherosclerotic lesions express matrix metalloproteinase (MMP)8, which possesses proteolytic activity on matrix proteins particularly fibrillar collagens and on nonmatrix proteins such as angiotensin (Ang) I. OBJECTIVE: We studied whether MMP8 plays a role in atherogenesis. METHODS AND RESULTS: In atherosclerosis-prone apolipoprotein E-deficient mice, inactivating MMP8 resulted in a substantial reduction in atherosclerotic lesion formation. Immunohistochemical examinations showed that atherosclerotic lesions in MMP8-deficient mice had significantly fewer macrophages but increased collagen content. In line with results of in vitro assays showing that Ang I cleavage by MMP8 generated Ang II, MMP8 knockout mice had lower Ang II levels and lower blood pressure. In addition, we found that products of Ang I cleavage by MMP8 increased vascular cell adhesion molecule (VCAM)-1 expression and that MMP8-deficient mice had reduced VCAM-1 expression in atherosclerotic lesions. Intravital microscopy analysis showed that leukocyte rolling and adhesion on vascular endothelium was reduced in MMP8 knockout mice. Furthermore, we detected an association between MMP8 gene variation and extent of coronary atherosclerosis in patients with coronary artery disease. A relationship among MMP8 gene variation, plasma VCAM-1 level, and atherosclerosis progression was also observed in a population-based, prospective study. CONCLUSIONS: These results indicate that MMP8 is an important player in atherosclerosis.

Paraoxonase Arg 192 allele is an independent risk factor for three-vessel stenosis of coronary artery disease.

The role of the paraoxonase (PON1) codon 192 polymorphism [glutamine (Q)/arginine (R)] in coronary artery disease (CAD) is controversial. The aim of the present study was to evaluate whether the PON1 gene polymorphism is an independent risk factor for severity of coronary artery disease in patients from west of Iran. The PON1-Arg-192 genotypes were detected by PCR-RFLP in 414 individuals undergoing their first coronary angiography. Patients were placed into one of two groups: CAD and control without CAD or diabetes. The frequency of PON1-Arg-192 allele was significantly higher in the CAD (23.4 vs. 16%, P = 0.032) than in the control group and there was a higher risk of developing CAD (OR = 1.6, P = 0.02). In addition, this difference remained significant after adjustment for without history of diabetes (OR = 1.47, P = 0.048), presence of normolipidemia and absence of history of blood pressure (OR = 1.4, P = 0.05). This result indicated PON1-Arg-192 allele is a risk factor of CAD also when correcting for conventional risk factors. We found a significant association between the PON1-Arg-192 genotype (QR + RR) and the extent of CAD in CAD patients and CAD subjects without diabetes, represented by the increased frequency of three-vessel disease with OR = 1.49, P = 0.046; χ2 = 3.82, P = 0.048 and OR = 1.46, P = 0.05; χ2 = 3.48, P = 0.051, respectively. The CAD patients carrying PON1-Arg-192 genotype (QR + RR) had lower plasma HDL-C level (P = 0.019) and higher plasma LDL-C(P = 0.01) and TG(P = 0.05). Our results indicated that PON1-Arg-192 allele can be important independent risk factor of CAD in a west population of Iran, with carriers of PON1-Arg-192 having an increased frequency of three-vessel disease and also having a distinct plasma lipids profile. Larger collaborative studies are needed to confirm these results.

The S447X variant of lipoprotein lipase gene is inversely associated with severity of coronary artery disease.

Hyperlipidemia is a major risk factor for coronary artery disease (CAD). Lipoprotein lipase (LPL) is an important enzyme in lipoprotein metabolism. S447X polymorphism of the LPL gene has been implicated in the pathogenesis of CAD. Carriers of X447 allele were reported to have lower triglyceride and higher high-density lipoprotein cholesterol levels as well as a reduced risk of CAD. We hypothesized that S447X gene polymorphism might have a protective effect for CAD. A total of 178 subjects (mean age 42.97 ± 6.5 years) who underwent coronary angiography for clinical indications were included in the study. The patients had been referred for evaluation of chest pain and/or abnormal stress tests, and were selected consecutively. Gensini scores were used to assess the severity of CAD; 97 patients were diagnosed with angiographically proven CAD, and 81 subjects did not display significant CAD (≥ 70%) angiographically. Genotyping of LPL S447X polymorphism was performed by real-time polymerase chain reaction amplification and fluorescent probe melting point analysis on the light cycler. The minor allele frequencies of LPL 447X allele were 11.1% and 6.2% among subjects without CAD compared with CAD subjects (P = 0.081) and 447X allele had favorable effects on lipid levels among CAD patients; 447X homozygotes and heterozygotes displayed lower total cholesterol (171 ± 37 vs 208 ± 48 mg/dl, P = 0.02), lower triglycerides (121 ± 72 vs 184 ± 86 mg/dl, P = 0.02), lower low-density lipoprotein cholesterol (102 ± 27 vs 129 ± 39 mg/dl, P = 0.03). Gensini scores were significantly lower among the heterozygotes and homozygotes of LPL 447X allele than in the LPL S447 homozygotes (15 ± 23 vs 25 ± 30, P = 0.048). S447X polymorphism of LPL gene may have a protective role for the severity of CAD. The beneficial effects of S447X polymorphism of the LPL gene may be through its favorable effects on lipid levels.

Reciprocal regulation of endothelial-mesenchymal transition by MAPK7 and EZH2 in intimal hyperplasia and coronary artery disease.

Endothelial-mesenchymal transition (EndMT) is a form of endothelial dysfunction wherein endothelial cells acquire a mesenchymal phenotype and lose endothelial functions, which contributes to the pathogenesis of intimal hyperplasia and atherosclerosis. The mitogen activated protein kinase 7 (MAPK7) inhibits EndMT and decreases the expression of the histone methyltransferase Enhancer-of-Zeste homologue 2 (EZH2), thereby maintaining endothelial quiescence. EZH2 is the catalytic subunit of the Polycomb Repressive Complex 2 that methylates lysine 27 on histone 3 (H3K27me3). It is elusive how the crosstalk between MAPK7 and EZH2 is regulated in the endothelium and if the balance between MAPK7 and EZH2 is disturbed in vascular disease. In human coronary artery disease, we assessed the expression levels of MAPK7 and EZH2 and found that with increasing intima/media thickness ratio, MAPK7 expression decreased, whereas EZH2 expression increased. In vitro, MAPK7 activation decreased EZH2 expression, whereas endothelial cells deficient of EZH2 had increased MAPK7 activity. MAPK7 activation results in increased expression of microRNA (miR)-101, a repressor of EZH2. This loss of EZH2 in turn results in the increased expression of the miR-200 family, culminating in decreased expression of the dual-specificity phosphatases 1 and 6 who may repress MAPK7 activity. Transfection of endothelial cells with miR-200 family members decreased the endothelial sensitivity to TGFß1-induced EndMT. In endothelial cells there is reciprocity between MAPK7 signaling and EZH2 expression and disturbances in this reciprocal signaling associate with the induction of EndMT and severity of human coronary artery disease.

Elevated CK-MB values after routine angioplasty predicts worse long-term prognosis in low-risk patients.

OBJECTIVES: The long-term prognostic value (>5 years) of elevated cardiac biomarkers after elective coronary angioplasty is yet not clear. Most previous studies have included high risk, unstable patients. The aim of this study was to determine the prognostic value of CK-MB mass > or = three times the reference after elective angioplasty in low-risk patients with stable angina. METHODS: A total of 278 consecutive patients were included in the final analysis. Patients with elevated CK-MB values at baseline, and those suffering an acute coronary syndrome <1 month before the time of inclusion, were excluded. Blood samples were drawn just before and 1-3 hours, 4-8 hours after the procedure and the next morning. Nineteen patients (6.8%) had peak CK-MB mass values > or =15 microg/L (three times the reference), and 259 patients had values <15 microg/L (defined as controls). No patient developed new Q-waves on ECG. The median follow-up time was 80.5 months. RESULTS: None of the patients died during the procedure or within the first 30 days after angioplasty, confirming a low risk cohort. All cause mortality, readmission for acute coronary syndromes and target lesion revascularisation (TLR) were more frequent in patients with high CK-MB, 42.1% vs. 22.8%, p=0.034 (log rank). In a multivariate logistic regression analysis, high CK-MB and former angioplasty were the only variables independently related to a reduced event-free survival. CONCLUSIONS: CK-MB mass values > or = three times the reference after elective angioplasty predicts reduced long-term event-free survival.

Paraoxonase 1 gene promoter polymorphisms are associated with the extent of stenosis in coronary arteries.

HDL-associated paraoxonase1 (PON1) is believed to be an important anti-oxidative enzyme in the retardation of atherosclerosis. In this study, we determined haplotypes of three SNPs within the PON1 gene promoter to elucidate association of functional sites with coronary artery disease (CAD). We applied a direct haplotyping procedure through ARMS (Amplification Refractory Mutation System) and RFLP (Restriction Fragment Length Polymorphism) analysis techniques. The haplotypes of the G(-907)C, A(-162)G and C(-107)T polymorphisms within the 5' region of the PON1 gene were determined in 99 patients and 66 controls who were evaluated angiographically for the presence and extent of stenosis in coronary arteries. The genotype and haplotype distributions had significant differences between patient subgroups (One-, Two- and Three-vessel disease) but not between the patient and control groups. Multivariate analyses suggested decreased arylesterase activity is the most important independent factor in the CAD severity. The increase of high activity variants [G(-907) and C(-107)] within the two-allelic haplotypes was reversely associated with the extent of stenosis in coronary arteries. However, we could not determine the independent involvement each of the C(-107)T and G(-907)C polymorphisms on the extent of stenosis. We found no significant association between the A(-162)G polymorphism and the extent of stenosis in vessels. The study indicated the association of polymorphic variations within the PON1 gene promoter haplotypes with the serum arlyesterase activity. The arlyesterase activity was also associated with the extent of stenosis in coronary arteries but not with primary development of atherosclerosis.

Prognostic value of troponin after elective percutaneous coronary intervention: A meta-analysis.

BACKGROUND: Although the prognostic importance of troponin in patients with anacute coronary syndrome is clear, the significance of troponin elevation after elective percutaneous coronary intervention (PCI) is a subject of debate. However, most studies up to now had a small sample size and insufficient events during follow-up. METHODS: Electronic and manual searches were performed of studies reporting on prognosis of troponin after elective PCI. A meta-analysis was done of all suitable studies, with death in follow-up as primary endpoint and the combination of death or nonfatal myocardial infarction in follow-up as secondary endpoint. RESULTS: 20 studies involving 15,581 patients were included. These studies were published between 1998 and 2007. Overall, troponin was elevated after elective PCI in 32.9% of patients. The follow-up period varied between 3 and 67 months (mean 16.3). Increased mortality was significantly associated with troponin elevation after PCI (4.4% vs. 3.3%, P = 0.001; OR 1.35). Furthermore, the combined endpoint of mortality or nonfatal myocardial infarction also occurred more often in patients with post-procedural troponin elevation (8.1% vs. 5.2%, P < 0.001; OR 1.59). CONCLUSIONS: According to this meta-analysis, troponin elevation after elective PCI provides important prognostic information.

Plasma myeloperoxidase is related to the severity of coronary artery disease.

OBJECTIVE: It has been shown that the main apolipoprotein of HDL, Apo A-1, is subjected to nitration by myeloperoxidase (MPO) and this oxidative modification renders HDL proatherogenic. The aim of this study is to evaluate the relationship between plasma MPO levels, and the severity of coronary artery disease. METHODS AND RESULTS: Forty-eight patients with coronary artery narrowing and 30 control subjects were enrolled in this study. The severity of the disease was assessed by Gensini scoring after angiography. MPO concentrations were determined by using an enzyme immunoassay. A subgroup of 30 patients underwent computerized tomography to determine the calcium load of coronary arteries. Plasma MPO levels were found significantly higher in patients with coronary artery disease than controls (4.27 [1.60 to 42.43] ng/mL vs. 2.93 [1.00 to 9.25] ng/mL, P = 0.002). MPO was positively correlated with both Gensini (r = 0.228, P = 0.044) and coronary calcium scores (r = 0.433, P = 0.017). The atherosclerotic burden was more strongly correlated with MPO levels than the traditional markers such as total cholesterol and HDL. CONCLUSIONS: We found that MPO levels were elevated in patients with coronary artery disease and this increase correlated with the extent and severity of atherosclerosis. Although it is a preliminary study with a relatively small group of subjects, we suggest that MPO might be evaluated as a new marker indicating the presence and severity of coronary artery disease.

Serum level of gamma-glutamyl transferase as a biomarker for predicting stenosis severity in patients with coronary artery disease.

BACKGROUND: Gamma glutamyl transferase (GGT) is associated with pathogenesis of various diseases such as coronary artery disease (CAD). GGT activity displays an essential role in the catabolism of glutathione which is reported as a major antioxidant. The aim of this study was to explore the association of GGT activity with obstruction severity of artery in 500 CAD patients. RESULTS: Our finding showed a significant association between serum GGT activity and CAD patients. In particular, the level of GGT in patients who had ≥50% obstruction was higher, compared to healthy and patients with less than 50% obstruction in their coronary arteries (the level of GGT in patients with at least one (1 SVD), two (2VD), three (3VD) coronary artery obstruction were 55.6±9.7, 71.7±12.7 and 84.7±13.4, while these values in patients with negative angio or control group were 28±10 and 17±4.6). Furthermore, the activity of this marker was associated with increased the risk of CAD (Odd ratio of GGT in 3VD group: 2, 95%CI: 1.8-2.3), which was also related with HDL-C. Of note, the level of GGT was enhanced progressively with increasing the obstruction severity of arteries. CONCLUSION: We demonstrate the prognostic value of serum level of GGT as a biomarker for predicting obstruction severity in patients with CAD.

Ossabaw Pigs With a PCSK9 Gain-of-Function Mutation Develop Accelerated Coronary Atherosclerotic Lesions: A Novel Model for Preclinical Studies.

BACKGROUND: Ossabaw pigs are unique miniature swine with genetic predisposition to develop metabolic syndrome and coronary atherosclerosis after extended periods receiving atherogenic diets. We have hypothesized that transgenic Ossabaw swine expressing chimp PCSK9 (proprotein convertase subtilisin-like/kexin type 9) containing the D374Y gain of function would develop familial hypercholesterolemia and coronary artery plaques more rapidly than Landrace swine with the same transgene. METHODS AND RESULTS: Ossabaw and Landrace PCSK9 gain-of-function founders were generated by Sleeping Beauty transposition and cloning. Histopathologic findings in the Ossabaw founder animal showed more advanced plaques and higher stenosis than in the Landrace founder, underscoring the Ossabaw genetic predisposition to atherosclerosis. We chose to further characterize the Ossabaw PCSK9 gain-of-function animals receiving standard or atherogenic diets in a 6-month longitudinal study using computed tomography, magnetic resonance (MR) imaging, intravascular ultrasound, and optical coherence tomography, followed by pathological analysis of atherosclerosis focused on the coronary arteries. The Ossabaw model was consistently hypercholesterolemic, with or without dietary challenge, and by 6 months had consistent and diffuse fibrofatty or fibroatheromatous plaques with necrosis, overlying fibrous caps, and calcification in up to 10% of coronary plaques. CONCLUSIONS: The Ossabaw PCSK9 gain-of-function model provides consistent and robust disease development in a time frame that is practical for use in preclinical therapeutic evaluation to drive innovation. Although no animal model perfectly mimics the human condition, this genetic large-animal model is a novel tool for testing therapeutic interventions in the context of developing and advanced coronary artery disease.