Integrin ß1 polymorphisms and bleeding risk after coronary artery stenting

Bleeding complications following percutaneous coronary intervention associate with increased mortality. However, the underlying molecular mechanisms are insufficiently understood. Platelet recruitment and activation at sites of vascular injury depends on the function of integrin adhesion receptors. Besides GPIIbIIIa as the most abundant integrin receptor, platelets relevantly express ß1 integrins. Experimental evidence from in vivo studies suggests a significant role of ß1 integrins in primary haemostasis. However, little is known about the clinical impact of genetic alterations of the β1 subunit, which might contribute to bleeding complications in patients. In this study, we performed DNA sequencing of patients suffering from bleeding complications after coronary artery stenting according to TIMI or BARC classification. We isolated DNA samples from 741 patients out of a cohort from 14,160 patients recruited in seven randomized clinical trials between June 2000 and May 2011. Subsequently, Sanger sequencing was performed covering the β1 integrin cytoplasmic activation domain (exon16) and its non-coding upstream region. Out of 764 patients suffering from bleeding complications, 741 DNA samples were successfully sequenced. Genotype variation was detected for SNP rs2153875 located within the non-coding upstream region with following allele frequency in study population: CC (7.3%), CA (35%) and AA (57.8%), which is similar to a general population cohort. Further, genotype variation in SNP rs2153875 do not associate with the frequency of TIMI or BARC classified access or non-access site bleedings. Genotype variations of the β1 integrin activation domain do not associate with bleeding risk after PCI.

     

Apolipoprotein E gene polymorphisms in Lebanese with hypercholesterolemia

Apolipoprotein E (ApoE) has an important role in the metabolism of lipids through its major isoforms (ε2, ε3, ε4). In particular, ApoE ε4, has been considered as a major genetic risk factor for cardiovascular diseases (CVD). The aim of our study is to investigate the frequency of ApoE gene polymorphisms (rs 429358C > T, rs 7412C > T) and their relationship to lipid parameters in a group of Lebanese hypercholesterolemic subjects (22 males and 24 females, aged 25–80 years). Lipid profile, apolipoproteins A-I and B were determined using fasting serum samples; and molecular analysis of ApoE polymorphisms using blood in EDTA tubes. The distribution of the four ApoE genotypes detected in this study was: ε3/ε3 (73.9%), ε3/ε4 (17.4%), ε2/ε3 (6.5%), and ε2/ε4 (2.2%) resulting in allelic frequencies for ε2, ε3 and ε4 of 4.3%, 85.9% and 9.8%, respectively. No association was determined among any of the lipid parameters, gender and ApoE genotypes. Lipid parameters were not statistically different among various ApoE genotypes (p > 0.05). ApoE ε2 frequency was found to be lower than that previously reported for healthy Lebanese (7.2%). CVD is one of the major leading causes of mortality in Lebanon with a reported prevalence of 12.2% in males and 7.7% in females, which incidentally agrees with our finding regarding ε4 allelic frequency of 13.6% in males and 6.3% in females. Consequently, larger prospective studies are recommended to highlight the correlation of ApoE polymorphisms to other biochemical and environmental factors involved in CVD.     

ApoC-III gene polymorphisms and risk of coronary artery disease

Several polymorphisms in the apolipoprotein C-III (apoC-III) gene have been associated with hypertriglyceridemia, but the link with coronary artery disease risk is still controversial. In particular, apoC-III promoter sequence variants in the insulin responsive element (IRE), constitutively resistant to downregulation by insulin, have never been investigated in this connection. We studied a total of 800 patients, 549 of whom had angiographically documented coronary atherosclerosis, whereas 251 had normal coronary arteriograms. We measured plasma lipids, insulin, apoA-I, apoB, and apoC-III and assessed three polymorphisms in the apoC-III gene, namely, T-455C in the IRE promoter region, C1100T in exon 3, and Sst1 polymorphic site (S1/S2) in the 3' untranslated region. Each variant influenced triglyceride levels, but only the T-455C (in homozygosity) and S2 alleles influenced apoC-III levels. In coronary artery disease (CAD) patients, 18.6% were homozygous for the -455C variant compared with only 9.2% in CAD-free group (P < 0.001). In logistic regression models, homozygosity for -455C variant was associated with a significantly increased risk of CAD (OR = 2.5 and 2.18 for unadjusted and adjusted models, respectively) suggesting that it represents an independent genetic susceptibility factor for CAD.     

Apolipoprotein E polymorphism in Omani dyslipidemic patients with and without coronary artery disease

Apolipoprotein E (APOE) polymorphism is a predictor of interindividual variability in plasma levels of lipids and lipoproteins and a predictor of risk of coronary artery disease (CAD). We studied the relationship between APOE polymorphism and lipid profiles and risk of CAD in Omani dyslipidemic patients. This retrospective study included 244 dyslipidemic patients, of whom 67 had CAD. Fasting blood glucose, lipids, and plasma lipoprotein levels were measured using standard methods, and APOE genotypes were detected by PCR-RFLP. The dyslipidemic patients had the following APOE allele frequencies: APOE*2, 0.030; APOE*3, 0.894; and APOE*4, 0.076. APOE allele frequencies between patients with and without CAD showed no significant differences. Compared to APOE*3/*3 homozygotes, APOE*4 allele patients had higher mean levels of low-density lipoprotein (LDL) cholesterol (p = 0.014), apoB (p = 0.031), lower mean levels of apoA1 (p = 0.043), and a trend of higher mean level of total cholesterol (p = 0.084). Thirty-one percent of patients with CAD had the APOE*4 allele compared to 26% with the APOE*3 allele, but this difference was not significant. Compared with APOE*3/*3 homozygotes, patients with the APOE*4 allele had 1.3 times higher risk for CAD after ignoring dyslipidemia, but this risk was modified after adjusting for dyslipidemia. In conclusion, among dyslipidemic patients, carriers of APOE*4 compared to homozygous carriers of APOE*3 had significantly higher levels of LDL cholesterol and apoB, but no relationship with CAD was found.     

An example of late regression of in-stent restenosis after bare metal coronary stenting

A 69-year-old female patient with hypertension and diabetes mellitus presented in September 2002 with an acute coronary syndrome. Coronary angiography demonstrated significant one-vessel disease (figure 1A) with a preserved left ventricular function.     

Diagnosis of coronary artery restenosis after radiologic endovascular dilatation]

Altogether 40 patients with stable angina of effort were investigated in a long-term period after roentgenovascular dilatation of one or two coronary arteries. Control coronarography was performed in 22 patients with lowered exercise tolerance. A reliable feature in the development of hemodynamically significant restenosis and/or "new" coronary stenosis in 11 patients was a combination of average and low exercise tolerance with its negative dynamics. For patients with I functional class, a sign of restenosis and/or "new" stenosis was the appearance of the ischemic shift of the CT-segment on ECG during bicycle testing. An efficient selection of patients resulted in increased sensitivity and specificity of noninvasive tests.     

Quantitative and qualitative assessment of X-ray morphology of coronary restenosis after balloon angioplasty and stenting

The study was undertaken to compare the data of quantitative angiographic analysis of early and late outcomes of intracoronary stenting (ICS) and balloon coronary angioplasty (BCA) with the X-Ray morphology of restenosis. The prospective study enrolled 67 patients undergone repeated coronary angiography 2-10 months after successful BCA. Group I included 34 patients with coronary restenosis. Group II comprised 33 patients without restenosis signs. Each group was divided into 2 subgroups: A--patients undergone BCA; B--patients undergone ICS. Subgroups IA and IB included 22 and 12 patients, respectively, and subgroups IIA and IIB consisted of 24 and 19. The X-ray morphology of the underlying versus restenosis lesions in the subgroups was quantitatively and qualitatively assessed. The findings have led to the following conclusions that ICS yields more optimal early and late angiographic results than does BCA; according to the site of restenosis against the underlying lesion, the following types of restenosis following BCA and ICS are identified: diffuse, localized, marginal, and mixed; restenosis after ICS is characterized by for concentric morphology while that following BCA preserves the morphology of a primary lesion.     

Synergistic effect between apolipoprotein E and apolipoprotein A1 gene polymorphisms in the risk for coronary artery disease

Alterations in lipid metabolism and genetic predisposition are major risk factors for coronary artery disease (CAD). Variations in genes involved in lipid metabolism may act synergistically to confer risk or protection against CAD. The objective of the present study was to determine such interactions in variants of apolipoprotein E and apolipoprotein A1 genes. One hundred and forty subjects with clinically confirmed CAD and 100 unrelated normal subjects participated in the study. Multiple regression analysis was used to relate lipid and apolipoprotein profiles with genotypes. Odd ratios were calculated for various combinations of ApoE and ApoA1 genotypes. Prevalence of ApoE 'E4' and ApoA1 'A' and 'T' alleles was significantly higher in patients than controls. Serum apolipoprotein E and apolipoprotein A1 levels were significantly lower in CAD patients than controls. When lipid parameters were related to genotypes, the polymorphisms associated to various markers were in agreement with previous reports. ApoE 2/4 genotype in combination with either ApoA1 heterozygous GA or CT genotype conferred higher risk of CAD. E3 allele in homozygous or heterozygous state in combination with ApoA1+83 CC genotype conferred highest protection (P < 0.05). Thus, it appears that ApoE and ApoA1 gene variants may act synergistically to associate with risk and protection against CAD.     

Non-alcoholic fatty liver disease and risk of in-stent restenosis after bare metal stenting in native coronary arteries

In-stent restenosis (ISR) remains the most common complication of percutaneous coronary intervention. Due to shared risk factors, it is postulated that non-alcoholic fatty liver disease (NAFLD) patients have an increased risk of ISR. This study aimed to determine the association between NAFLD and ISR in patients after bare metal stenting. This study included a cohort of 210 consecutive patients (150 men and 60 women) undergoing follow-up angiography. The primary end-point was angiographic ISR. Multivariate logistic regression analysis was used to identify independent risk factors for ISR. The cumulative ISR rate during follow-up was analyzed by Kaplan–Meier method. Subgroup analyses were also done for different gender. The ISR rate was 29.5 %. Patients with NAFLD had a significantly higher prevalence of ISR than patients without NAFLD (43.3 vs. 16.0 %, P < 0.001). In logistic regression analysis, NAFLD was associated with increased ISR, independent of low-density lipoprotein cholesterol, body mass index (adjusted odds ratio: 2.688, 95 % confidence intervals: 1.285–5.537, P < 0.001). Male NAFLD patients had a higher prevalence of ISR than patients without NAFLD (48.4 vs. 15.3 %, P < 0.001), while the prevalence of ISR in female patients with and without NAFLD were comparable (7.7 vs. 17.0 %, P = 0.404). Kaplan–Meier analysis showed a significant association between NAFLD and ISR in all patients (log-rank P = 0.008) and in male subgroup (log-rank P = 0.033), but not in female subgroup (log-rank P = 0.313). This preliminary study suggests that NAFLD could independently associate with a high prevalence of ISR, especially in male patients.     

Extensive right coronary artery thrombosis

A 65-year-old man presented with a non-ST-elevation acute coronary syndrome. His medical history was unremarkable. Apart from a brother, who sustained a myocardial infarction at the age of 40, no cardiovascular risk factors were present. Coronary angiography revealed normal left anterior descending and circumflex arteries. The right coronary artery was subtotally occluded with an extensive thrombus running into the posterolateral branch (figures 1A and B). Despite appropriate medical treatment, intermittent chest pain persisted. The patient underwent a percutaneous coronary intervention with mechanical removal of the thrombus by aspiration followed by balloon dilatation.     

Long-term outcome after coronary stenting

The present review assesses the data on long-term outcome after coronary stenting. Histological, angiographical and intravascular imaging data have shown that the insertion of stents constitutes only a transient stimulus to lumen renarrowing, that this process is almost complete at 6 months and that a certain degree of neointima regression is also possible after this time. Clinical data have confirmed the sustained benefit of stenting in the long term. Careful selection of optimal stent designs and application of the recent advances in adjunctive pharmacological therapy are currently effective strategies to improve both short-and long-term results with coronary stenting. However, further efforts are needed and are ongoing to combat restenosis, a process that counters the excellent short-term results of stenting in the long term.     

Apolipoprotein E and A-IV polymorphisms in ethnic Russians living in Estonia

137 Russians living in Estonia was screened by isoelectric focusing and immunoblotting procedures to determine the distribution of genetic variations in apolipoprotein E (apoE) and apolipoprotein A-IV (apoA-IV) genes. The apoA-IV-2 allele and epsilon4 allele frequency of the Russians tended to be lower than in most other European populations.     

Periostin gene polymorphisms, protein levels and risk of incident coronary artery disease

Vascular endothelial growth factor and its receptor the kinase domain receptor play critical roles in the pathogenesis of coronary artery disease. Periostin is an up-regulator of kinase domain receptor expression. The purpose of this study was to determine whether polymorphisms in periostin are associated with the risk of coronary artery disease. Two single nucleotide polymorphisms (SNP C-33G, SNP A-953T) within the promoter region were chosen for further analyses. A case–control study was carried out with patients of Han Chinese ethnicity, which consisted of 492 coronary artery disease cases and 498 controls. Genotyping was performed by means of PCR and restriction fragment length polymorphism (PCR–RFLP) and the plasma level of periostin was measured by enzyme-linked immunosorbent assay (ELISA). In our study, the TT genotype of SNP-A953T was present in the general Chinese population (3.5%), but not in the Han Chinese from Beijing Project (HAPMAP CHB). Plasma periostin concentrations were elevated significantly in patients with coronary artery disease (7.96 ± 8.33 nmol/l) compared with those in healthy volunteers (3.93 ± 1.71 nmol/l) (P = 0.005). There was a significant correlation between the 953T genotype and the plasma level of periostin (r ² = −0.490, P = 0.039). The prevalence of the TT genotype in patients was associated with a slightly lower risk of coronary artery disease (OR = 0.443, 95% CI = 0.200–0.982), but was not significant after correction (OR = 0.427, 95% CI = 0.146–1.250). The periostin-33G allele frequency was not significantly different in cases versus controls. Our data suggest that plasma periostin level may serve as a biomarker for the risk of coronary artery disease, but the periostin polymorphisms SNPC-33G and SNPA-953T were not significantly associated with the risk of coronary artery disease in this Chinese population. Although a major effect of the SNPs in the periostin genes on coronary artery disease susceptibility was excluded, the effect of the A-953T SNP on susceptibility and protein expression needs further investigation.     

Apolipoprotein E phenotype and gene distribution in The Netherlands

2,000 male individuals randomly selected from three different areas in The Netherlands were phenotyped for apolipoprotein E. The apolipoprotein E gene frequencies and phenotype distribution did not differ significantly from that of previously studied populations, with one exception: the epsilon 4 frequency was significantly lower than that in the Finnish population.     

Impact of MCP-1 and CCR-2 gene polymorphisms on coronary artery disease susceptibility

Coronary artery disease (CAD) was the second leading cause of death during the last 3 years in Taiwan. Smooth muscle cells, monocytes/macrophages, and endothelial cells produce monocyte chemoattractant protein-1 (MCP-1) within atherosclerotic plaques following binding to the chemokine receptor-2 (CCR-2). Previous studies have well-documented the association between MCP-1 expression and susceptibility to, or clinicopathological features, of CAD. This study investigated the relationships between MCP-1-2518A/G and CCR-2-V64I genetic polymorphisms and CAD in the Taiwanese population. A total of 608 subjects, including 392 non-CAD controls and 216 patients with CAD, were recruited and subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to evaluate the effects of these two polymorphic variants on CAD. Results indicated a significant association between MCP-1 -2548 gene polymorphism and susceptibility to CAD. GG genotypes (OR = 1.629; 95 % CI = 1.003-2.644), or individuals with at least one G allele (OR = 1.511; 95 % CI = 1.006-2.270), had a higher risk of CAD as compared with AA genotypes. Results also revealed that subjects with at least one A allele of the V64I CCR2 gene polymorphism had significantly increased risk of CAD. G allele in MCP-1-2518 might contribute to higher prevalence of atrial fibrillation in CAD patients (OR = 4.254; p < 0.05). In conclusion, MCP-1-2518G and CCR-2 64I gene polymorphisms represent important factors in determining susceptibility to CAD, and the contribution of MCP-1-2518G could be through effects on atrial fibrillation in CAD patients.     

Apolipoprotein B, apolipoprotein E, and angiotensin-converting enzyme polymorphisms in 2 Italian populations at different risk for coronary artery disease and comparison of allele frequencies among European populations

Polymorphisms at the apolipoprotein B (APOB XbaI, EcoRI, insertion-deletion), apolipoprotein E (APOE), and angiotensin-converting enzyme (ACE) loci are thought to be involved in susceptibility to coronary artery disease (CAD) and myocardial infarction. The aim of this study was to determine whether the allele distribution of the APOB, APOE, and ACE polymorphisms is different in 2 Italian regions with higher (northern Italy) and lower (Sardinia) CAD occurrence. The frequencies of the APOB and APOE alleles that are considered CAD risk factors were higher in northern Italy (APOB X- = 0.655; APOB R- = 0.198; APOB insertion = 0.757; APOE*4 = 0.110) than in Sardinia (APOB X- = 0.568; APOB R- = 0.159; APOB insertion = 0.680; APOE*4 = 0.052), although only APOE allele frequencies differed significantly (p = 0.001). ACE deletion allele frequencies in the 2 geographic areas showed an opposite pattern (northern Italy = 0.658; Sardinia = 0.721). Furthermore, we investigated the impact of APOB and APOE polymorphisms on interindividual variation in total cholesterol level in the 2 Italian samples, which differ in dietary habits. Only APOE phenotypes showed different mean levels of total cholesterol; the association was significant only in northern Italy (p = 0.04), where continental dietary habits and higher mean cholesterol levels prevail. These results support the suggestion that the cholesterol increasing effect of APOE*4 is environmentally mediated. Analysis of allele distributions among European populations, with remarkable differences in CAD prevalence, revealed a constant positive relationship between APOE*4 allele frequency and CAD incidence. The highest frequencies of APOB X- and R- were observed in Finland, where the incidence of CAD is high, and there is a partial agreement between APOB R- frequency and CAD occurrence across Europe, while APOB insertion and ACE deletion alleles are evenly distributed among European populations.     

Apolipoprotein E levels in cerebrospinal fluid and the effects of ABCA1 polymorphisms

Background

Animal studies suggest that brain apolipoprotein E (apoE) levels influence amyloid-β (Aβ) deposition and thus risk for Alzheimer's disease (AD). We have previously demonstrated that deletion of the ATP-binding cassette A1 transporter (ABCA1) in mice causes dramatic reductions in brain and cerebrospinal fluid (CSF) apoE levels and lipidation. To examine whether polymorphisms in ABCA1 affect CSF apoE levels in humans, we measured apoE in CSF taken from 168 subjects who were 43 to 91 years old and were either cognitively normal or who had mild AD. We then genotyped the subjects for ten previously identified ABCA1 single nucleotide polymorphisms (SNPs).

Results

In all subjects, the mean CSF apoE level was 9.09 μg/ml with a standard deviation of 2.70 μg/ml. Levels of apoE in CSF samples taken from the same individual two weeks apart were strongly correlated (r² = 0.93, p < 0.01). In contrast, CSF apoE levels in different individuals varied widely (coefficient of variation = 46%). CSF apoE levels did not vary according to AD status, APOE genotype, gender or race. Average apoE levels increased with age by ~0.5 μg/ml per 10 years (r² = 0.05, p = 0.003). We found no significant associations between CSF apoE levels and the ten ABCA1 SNPs we genotyped. Moreover, in a separate sample of 1225 AD cases and 1431 controls, we found no association between the ABCA1 SNP rs2230806 and AD as has been previously reported.

Conclusion

We found that CSF apoE levels vary widely between individuals, but are stable within individuals over a two-week interval. AD status, APOE genotype, gender and race do not affect CSF apoE levels, but average CSF apoE levels increase with age. Given the lack of association between CSF apoE levels and genotypes for the ABCA1 SNPs we examined, either these SNPs do not affect ABCA1 function or if they do, they do not have strong effects in the CNS. Finally, we find no evidence for an association between the ABCA1 SNP rs2230806 and AD in a large sample set.