Endothelial nitric oxide synthase Asp298Glu (894G/T) gene polymorphism as a possible risk factor for the coronary slow flow phenomenon among Iranians.

BACKGROUND: Mounting evidence indicates an association between endothelial dysfunction and the coronary slow flow phenomenon (CSFP). In the present study, we aimed to evaluate the possible role of endothelial nitric oxide synthase (eNOS) 894G/T and interleukin-1ß (IL-1ß) 315C/T polymorphisms as possible risk factors for CSFP. METHODS: This prospective study enrolled patients with CSFP and individuals with normal coronary arteries. Genotypes were assessed using regular polymerase chain reaction and direct Sanger-sequencing techniques. RESULTS: The study population consisted of 267 individuals: 180 patients with CSFP (49 women [27.2%]) at a median age of 55 (48-62) years and 87 controls with normal coronary arteries (56 women [64.4%]) at a median age of 47 (41-58) years. The allelic distribution of eNOS 894G/T was significantly associated with CSFP (odds ratio [OR], 1.58; 95% confidence interval (CI), 1.04-2.42; P = 0.03). This polymorphism increased the risk of CSFP under the dominant model (OR 1.73; 95% CI I.02-2.95; P = 0.04). However, the allelic frequencies (1.05; 95% CI 0.68-1.59; P = 0.83) and genotypic frequencies (0.88; 95% CI 0.52-1.49; P = 0.63) of the IL-1ß 315C/T polymorphism were not associated with the incidence of CSFP in the Iranian population. CONCLUSIONS: The CSFP and control groups were statistically different regarding the eNOS 894G/T polymorphism. Our findings also demonstrated that the IL-1ß 315C/T polymorphism was not a risk factor for CSFP.

Role of polymorphisms of the endothelial nitric oxide synthase gene in predicting slow-flow phenomenon after primary percutaneous coronary intervention.

OBJECTIVE: The aim of the present study was to examine the association between 2 polymorphisms of the endothelial nitric oxide (eNOS) gene (-786T>C and +894G>T) and the no-reflow/slow-flow phenomenon in post-primary percutaneous coronary intervention (PPCI) patients. METHODS: A total of 103 post-PPCI patients were enrolled. Coronary no-reflow phenomenon was defined as a Thrombolysis in Myocardial Infarction (TIMI) flow grade 0-1 and coronary slow-flow phenomenon (CSFP) was defined as a TIMI flow grade ≤2. RESULTS: Due to the small number of post-PPCI patients with the no-reflow phenomenon (n=4), the primary comparison was made between CSFP (n=20) and normal flow (n=83) groups. There was a greater frequency of CSFP among carriers of the -786C allele of the eNOS -786T>C polymorphism (odds ratio [OR]: 3.90; 95% confidence interval [CI]: 0.87-17.45; p=0.07). However, no such association was detected between the +894T allele of the eNOS +894G>T and CSFP (OR: 0.92; 95% CI: 0.21-3.98; p=0.91). In the adjusted analysis, the -786T>C polymorphism did not reach statistical significance. CONCLUSION: There was no significant association between CSFP and 2 of the most common polymorphisms of the eNOS gene in post-PPCI patients.

Relationship between circulating miRNA-30e and no-reflow phenomenon in STEMI patients undergoing primary coronary intervention.

To investigate the relationship between miRNA-30e level in circulation and no-reflow phenomenon in patients with acute ST-segment elevation myocardial infarction (STEMI) during primary percutaneous coronary intervention (pPCI). A total of 255 consecutive patients with STEMI undergoing pPCI were enrolled in this study. These patients were divided into two groups according to the occurrence of reflow during pPCI, namely normal-reflow group with 214 cases and no-reflow group with 41 cases. The plasma levels of miRNA-30e were quantified using real-time quantitative polymerase chain reaction. The plasma levels of miRNA-30e were significantly lower in the no-reflow group as compared to the normal-reflow group (p < .05). Also, miRNA-30e was positively correlated with left ventricular ejection fraction (LVEF) and negatively correlated with hs-CRP levels (p < .05). Multivariate logistic regression analyses indicated that the plasma level of miRNA-30e (OR = 0.732, 95% CI 0.674-0.851, p = .034), hs-CRP (OR = 1.353, 95% CI 1.129-1.635, p = .012) and Killip class ≥2 at admission (OR = 1.263, 95% CI 1.023-1.532, p = .027), were independent risk factors for no-reflow during pPCI. When plasma miRNA-30e level was used as the test variable, the area under the curve was 0.914 (p < .05) by ROC curve analysis. Lower miRNA-30e levels at admission are associated with no-reflow in STEMI patients undergoing pPCI and may play an important role in the pathogenesis of no-reflow. Plasma miRNA-30e level was an independent predictor of no-reflow during pPCI in patients with STEMI. Therefore, early detection of plasma miRNA-30e level can be a preliminary assessment for risk of no-reflow during pPCI.

Association of Interleukin-1 Gene cluster polymorphisms with coronary slow flow phenomenon.

OBJECTIVE: Coronary slow flow phenomenon (CSFP) is characterized by the decreased rate of contrast progression in epicardial coronary arteries in the absence of significant coronary stenosis. Mounting evidence has showed a significant association between inflammation and CSFP severity. This study aimed to evaluate possible associations between interleukin-1 receptor antagonist (IL-1ra) gene variable number tandem repeat (VNTR), IL-1ß -511 single nucleotide (SNP), and IL-1ß+3954 SNP mutations with CSFP. METHODS: Forty-eight patients with CSFP and 62 controls with angiographically normal coronary arteries were prospectively enrolled in the study. Genotypes were assessed using the polymerase chain reaction (PCR)-based restriction fragment length polymorphism (PCR-RFLP) technique. RESULTS: Homozygote genotype for allele 2 of+3954 C>T 2/2 genotype was significantly more frequent in patients with CSFP than in the control group, whereas 1/2 genotype was more frequent in the control group (35.4% versus 14.5% for 2/2 genotype and 25% versus 35.5% for 1/2 genotype in CSFP and control groups, respectively, X2=6.6; p=0.04). The allelic frequency of allele 2 of this polymorphism was significantly higher in the CSFP group than in the control group (47.9% versus 28.6% in the control group, X2=5.6; p=0.02). However, there was no significant difference with regard to genotype or allelic frequencies of IL-1ra VNTR or IL-1ß -511 SNP polymorphisms between patients with CSFP and controls. CONCLUSION: IL-1ß+3954 SNP mutations are significantly more common in patients with CSFP. It may suggest that the tendency for inflammation may contribute to the presence of this phenomenon.

The Relationship between Interleukin-6 Promotor Polymorphisms and Slow Coronary Flow Phenomenon.

BACKGROUND: Several lines of evidence suggest that slow coronary flow (SCF) phenomenon seems to be an early form of atherosclerosis and low-grade inflammation plays a role in the development of SCF. Interleukin-6 (IL-6) is a pleiotropic cytokine, functions as a mediator of inflammatory response, and has both pro-inflammatory and anti-inflammatory properties. The aim of the present study is to investigate the relationship between IL-6 -634C/G polymorphism and SCF in Han Chinese. METHODS: 250 subjects who underwent coronary angiography and had normal coronary arteries of varying coronary flow rates without any atherosclerotic lesion were enrolled in this study. 41 patients who had thrombolysis in myocardial infarction frame counts (TFC) above the normal cutoffs were considered to have SCF and 209 subjects within normal limits served as normal coronary flow (NCF) group. The PCR-based restriction fragment length polymorphism (PCR-RFLP) technique was used to assess the genotypes. RESULTS: The distribution of the IL-6 -634C/G genotypes (CC, CG, and GG) was 56.94%, 37.80%, and 5.26% in the NCF subjects, and 36.59%, 48.78%, and 14.63% in the SCF group, respectively (p = 0.0173). The frequency of the G allele in the SCF (39.02%) group was significantly higher than that in the NCF (24.16%) group (p = 0.0054). Compared with the CC genotype, the G allele carriers (CG + GG genotypes) had increased risk of SCF in both unadjusted and adjusted analyses. In SCF patients, the average serum IL-6 levels (pg/mL) in CG + GG genotype (4.78 ± 0.42) were statistically higher than in CC genotype (3.93 ± 0.36) (p = 0.0000). CONCLUSIONS: Our data support that IL-6 -634C/G polymorphism is associated with SCF and the G allele has increased risk for SCF in Han Chinese.

Sodium tanshinone IIA sulfonate ameliorates experimental coronary no-reflow phenomenon through down-regulation of FGL2.

AIMS: The effects of sodium tanshinone IIA sulfonate (STS) on coronary no-reflow (CNR) relevant to microvascular obstruction (MVO) remain unknown. Studies had shown that fibrinogen-like protein 2 (FGL2) expressed in microvascular endothelial cells (MECs) is a key mediator in MVO. Thus, we aimed to elucidate the roles of STS in CNR and relations between STS and FGL2. MAIN METHODS: Myocardial ischemia/reperfusion was selected to represent CNR model. The no-reflow zone and infarct area were assessed using Thioflavin S and TTC staining, and cardiac functional parameters were detected using echocardiography. Western blot was used to detected FGL2 level, fibrin level, protease-activated receptor-1 (PAR-1) activation and inflammation cells infiltration. FGL2 and inflammation cells were also identified by IHC. Microthrombus was detected by Carstairs' and MSB staining. We also detected the roles of STS on FGL2 expression, thrombin generation, phospho-Akt and NF-κB levels in MECs. KEY FINDINGS: Upon treatment with STS in CNR model, the no-reflow and infarct areas decreased significantly and cardiac function improved. The FGL2 expression was inhibited by STS in vivo as well as in vitro with thrombin generation inhibition. In addition, STS up-regulates Akt phosphorylation and suppressed NF-κB expression in activated MECs. Furthermore, fibrin deposition, PAR-1 activation and inflammatory response were inhibited with STS administration in CNR model. SIGNIFICANCE: Our results displayed a novel pharmacological action of STS on CNR. STS is able to ameliorate CNR through inhibition of FGL2 expression mediated by Akt and NF-κB pathways as well as prevention of MVO by suppressing fibrin deposition and inflammation.

Relationship between methylenetetrahydrofolate reductase gene polymorphism and the coronary slow flow phenomenon.

OBJECTIVE: To investigate the correlation between methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism and the coronary slow flow phenomenon (CSFP), and to discover the involvement of genetic factors in CSFP. PARTICIPANTS AND METHODS: Seventy-five patients with normal angiographic coronary arteries were recruited between June 2012 and June 2013. MTHFR C677T genotypes were sequenced by pyrosequencing, whereas the concentration of homocysteine (Hcy) was determined using the enzymatic cycling assay. RESULTS: Compared with the controls, the CSFP patients had higher Hcy concentrations and higher male morbidity. The CSFP patients showed higher frequencies of MTHFR 677(TT+TC) genotypes and the 677T allele compared with the controls. Plasma Hcy levels and male morbidity were correlated positively with the average corrected TIMI frame count. Multiple linear regression and logistic regression analysis indicated that both Hcy and male sex were risk factors for CSFP. MTHFR C677T genotypes and the frequency distribution of 677T allele complied with Hardy-Weinberg equilibrium. CONCLUSION: CSFP was associated with a high level of plasma Hcy, and men were more vulnerable to CSFP. By regulating the plasma Hcy level, the MTHFR C677T gene polymorphism and folic acid level might be involved in the occurrence of CSFP.

Association between the Glu298Asp and 4b/4a polymorphisms of endothelial nitric oxide synthase and coronary slow flow in the North Indian population.

RATIONALE: Genetic variants in endothelial nitric oxide synthase gene (NOS3) leading to endothelial dysfunction may be predispose to the coronary slow-flow phenomenon (CSFP). METHODS AND RESULTS: In this study, we examined the relationship between Glu298Asp (894G/T) and 4b/4a polymorphisms of NOS3 and CSFP. A total of 27 patients with CSFP but otherwise normal coronary arteries (mean age 50.4±8.2 years) and 200 controls with a normal coronary angiogram (mean age 53.1±8.6 years) were screened for Glu298Asp and 4b/4a polymorphisms by restriction fragment length polymorphism and PCR, respectively. Nitric oxide levels were determined using Griess' enzymatic method for an association with the polymorphisms. The genotype distribution of the Glu298Asp polymorphism differed significantly between the CSFP patients and controls (P=0.004). The dominant genetic model showed that GT+TT was significantly prevalent in patients in comparison with controls (P=0.014) and the T allele was significantly prevalent in patients (P=0.002). The genetic distribution of 4b/4a differed significantly for the heterozygous genotype ba (P=0.047). The overdominant genetic model re-established that the ba genotype was significantly prevalent in patients (P=0.044). Nitric oxide level was higher in patients than in controls, the values being 144.51±43.25 and 129.64±29.47 µmol/l, respectively (P>0.05). The genotypes of Glu298Asp showed a trend of association with nitric oxide levels, which decreased linearly in the order of GG, GT, and TT (P>0.05). CONCLUSION: The Glu298Asp polymorphism of NOS3 associates with CSFP.

Evaluation of coronary microvascular function and nitric oxide synthase intron 4a/b polymorphism in patients with coronary slow flow.

OBJECTIVE: Slow coronary flow (SCF) is reported to be associated with increased risk of cardiovascular disease. We have used coronary flow reserve measurement by transthoracic Doppler echocardiography to determine coronary microvascular function in patients with SCF and to determine whether the intron 4a/b polymorphism of the eNOS gene influences coronary endothelial function. METHODS: Overall, 96 patients with SCF and 79 controls were enrolled in the study. Coronary flow was quantified according to the thrombolysis in myocardial infarction (TIMI) frame count (TFC) on angiogram. Coronary diastolic peak flow velocities (DPFV) were measured with color Doppler flow mapping at baseline and after dipyridamole infusion. Coronary flow reserve was calculated as the ratio of hyperemic to baseline DPFV. The eNOS 4a/b polymorphism was detected by PCR. Patients with diabetes were excluded from the study. RESULTS: The SCF group was comparable to the control group in terms of demographic and clinical characteristics, except for hemoglobin and HDL-cholesterol levels, TFC of the left anterior descending artery, the circumflex artery, and the right coronary artery; the mean TFC was higher in the SCF group. Hyperemic DPFV and the hyperemic/baseline DPFV ratio were significantly lower in the SCF group when compared with the control group. However, baseline DPFV were similar in both groups. The number of patients with eNOS4 a/a and eNOS4 a/b phenotypes was statistically higher in SCF groups. The frequency of allele 'a' of the eNOS4 gene was also statistically higher in the SCF group. When patients were grouped according to the presence or absence of allele 'a' of the eNOS4 gene, statistically significant differences were found in the TFC of the left anterior descending artery, the circumflex artery; mean TFC; baseline DPFV; and hyperemic/baseline DPFV. Univariate analysis in which eNOS4 b/b was used as the referent group showed that the presence of allele 'a' of the eNOS4 gene significantly predicted SCF (odds ratio: 2.79, 95% confidence interval: 1.32-5.89; P=0.007). In multivariate analysis using a model adjusted for variables with a P value lower than 0.10 in univariate analyses, the presence of allele 'a' of the eNOS4 gene was found to be an independent predictor of SCF (odds ratio: 3.22, 95% confidence interval: 1.28-8.82; P=0.013). CONCLUSION: The presence of allele 'a' may be a risk factor for microvascular endothelial dysfunction and higher TFCs in SCF patients.

No-reflow disrupts the expression and distribution of connexin 43 in a swine model.

INTRODUCTION AND OBJECTIVES: Ischemia and ischemia/reperfusion can dephosphorylate and redistribute connexin 43 (Cx43). But it is unknown whether no-reflow phenomenon has an effect on the expression and distribution of Cx43 after acute infarction and reperfusion. METHODS: 21 open-chest pigs were divided into three groups. Left anterior descending artery (LAD) occlusion for 90 min before 180 min of reperfusion was made in ischemia/reperfusion group. The pigs in ischemia groups were either subjected to LAD ligation for 90 min or for 270 min. No-reflow and risk regions were determined pathologically by dye staining. Cx43 expression was measured by western blotting and quantitative RT-PCR analysis. Cx43 spatial distribution was shown by immunofluorescence examination. RESULTS: The content of phosphorylated and mRNA of Cx43 were higher in reflow region than in the no-reflow or sustained ischemic region. The distribution of Cx43 was also altered in no-reflow region. CONCLUSIONS: There are some differences in synthesis, expression and distribution of myocardial Cx43 at microvascular level after ischemia/reperfusion. Cx43 is partially rephosphorylated with reperfusion only in the reflow myocardium.