Early sign of atherosclerosis in slow coronary flow and relationship with angiotensin-converting enzyme I/D polymorphism

Single Nucleotide Polymorphisms in Coronary Microvascular Dysfunction

Coronary microvascular dysfunction is an underdiagnosed pathologic process that is associated with adverse clinical outcomes. There are data to suggest that coronary microvascular dysfunction, in some cases, may be genetically determined. We present an updated review of single nucleotide polymorphisms in coronary microvascular dysfunction.

Alprostadil vs. isosorbide dinitrate in ameliorating angina episodes in patients with coronary slow flow phenomenon: A randomized controlled trial

Background

The optimum therapy for coronary slow flow phenomenon (CSFP) stays debatable. This study compared the effectiveness of alprostadil with isosorbide dinitrate in alleviating angina episodes in CSFP patients.

Methods

In this prospective, randomized controlled study, 102 patients with CSFP without severe coronary artery stenosis that exhibited stable angina were allocated randomly in a ratio of 1:1 to either the alprostadil group (40 μg, three times per day, n = 51) or the isosorbide dinitrate group (5 mg, three times per day, n = 51). Frequency of angina events, intensity of suffering, and the Canadian Cardiovascular Society (CCS) grading of angina pectoris were evaluated at baseline and one month after. Additionally, the Seattle Angina Questionnaire (SAQ) was assessed.

Results

Baseline characteristics were comparable between the two groups. At 1-month follow-up, patients administered with alprostadil experienced fewer angina episodes [episodes per week, 1 (2) vs. 2 (2), P < 0.001] and less pain intensity [self-evaluated pain score, 2 (3) vs. 3 (4), P < 0.001] than those with isosorbide dinitrate. In the alprostadil group, 78.4% of patients were classified as CCS class I, significantly higher than the 47.1% seen in the isosorbide dinitrate group (P = 0.001). Furthermore, treatment of alprostadil led to a significant improvement in the SAQ score (7.09 U, 95% CI: 4.22–9.96, P < 0.001) compared to isosorbide dinitrate. Additionally, fewer patients suffered headaches when receiving alprostadil (7.8% vs. 19.6%, P = 0.084).

Conclusion

Alprostadil was more effective in ameliorating angina symptoms in CSFP patients than isosorbide dinitrate.

Clinical trial registration

[www.chictr.org.cn], identifier [ChiCTR2000033233].

Angiotensin-Converting Enzyme Gene D/I Polymorphism in Relation to Endothelial Function and Endothelial-Released Factors in Chinese Women

Many studies have investigated the relationship between angiotensin-converting enzyme (ACE) D/I polymorphism and cardiovascular disease or endothelial dysfunction; however, hardly any of these studies has taken aging or menopause into consideration. Furthermore, despite that many studies have examined the regulatory effects of endothelial-released factors (ERFs) on endothelial function, no study has evaluated the relationship between ERFs and endothelial function with respect to ACE D/I polymorphism and menopause status. To answer these questions, 391 healthy Chinese women over a wide range of ages (22-75 years) were enrolled and divided into pre-menopause group and post-menopause group. After ACE D/I genotype being identified, the women were then classified into either DI/II or DD genotype. Flow-mediated dilatation (FMD) of brachial endothelium and plasma levels of ERFs: nitric oxide (NO), endothelin-1 (ET-1), and angiotensin II (Ang II) were measured. The results showed that frequencies of ACE D/I genotypes were in accordance with the Hardy-Weinberg equilibrium, and the frequency of I allele was higher than D allele. In pre-menopause group, FMD was significantly higher in women of DI/II than DD (P = 0.032), and age-dependent in both genotypes (DD, P = 0.0472; DI/II, P < 0.0001). In post-menopause group, FMD was similar between women of DI/II and DD, and age-dependent only in women of DI/II (P < 0.0001). In pre-menopause group, Ang II level was significantly higher in women of DD than DI/II (P = 0.029), and FMD was significantly correlated with all ERFs in women of DD (NO, P = 0.032; ET-1, P = 0.017; Ang II, P = 0.002), but only with Ang II in women of DI/II (P = 0.026). In post-menopause group, no significant difference was observed in any ERF between women of DI/II and DD, and FMD was only significantly correlated with ET-1 in women of DD (P = 0.010). In summary, FMD in women of DI/II was superior to DD in pre-menopause and more age-dependent than DD in post-menopause, and FMD was closely associated with ERFs. In conclusion, Chinese women of DI/II seem to have lower risk than DD in pre-menopause, but similar risk as DD in post-menopause in developing cardiovascular disease.

Association between increased serum alkaline phosphatase and the coronary slow flow phenomenon

BACKGROUND

Despite marked advances in our understanding of the pathophysiology of the coronary slow flow phenomenon (CSFP), the exact mechanism remains unclear. Previous studies have suggested that CSFP might be associated with generalized atherosclerosis, endothelial dysfunction, and low-grade chronic inflammation. High serum alkaline phosphatase (ALP) levels are associated with vascular calcification, atherosclerotic disease, and an increased risk of cardiovascular events. However, the relationship between ALP and CSFP is unclear.

METHODS

We investigated 64 patients with angiographically proven CSFP and 50 with normal coronary flow. Serum ALP levels were measured in all studied individuals.

RESULTS

Serum ALP levels in patients with CSFP were significantly higher than those in the control group (70.5 ± 17.1 vs. 61.9 ± 16.1 U/L, P = 0.007). A positive association was observed (r = 0.42, P = 0.032) between serum ALP levels and the mean thrombolysis in myocardial infarction frame count (mTFC). Regression analysis showed a high serum ALP level was the only independent predictor of the mTFC (β = 0.309, P < 0.001). Moreover, our study showed that a serum ALP level > 67.5 U/L was a predictor of CSFP (sensitivity = 83.3%, specificity = 84.1%).

CONCLUSIONS

Patients with CSFP show high serum ALP levels, which may be associated with the pathogenesis of CSFP. A high serum ALP level is a predictor of CSFP. Future studies are needed to clarify the role of ALP in patients with CSFP.

Circulating miRNA-155 as a Potential Biomarker for Coronary Slow Flow

Objective

Recent studies have demonstrated that miRNA-155 is involved in the occurrence and development of atherosclerosis. Furthermore, miRNA-155 has emerged as a new indirect marker for inflammation associated with adverse outcomes in oncology and cardiovascular diseases. This study investigated the correlation between the levels of miRNA-155 and coronary slow flow (CSF).

Methods

A total of 66 patients with CSF and 66 patients with normal coronary flow were enrolled in this study. Coronary flow velocity was determined using the thrombolysis in myocardial infarction frame count (TFC) method. The plasma levels of miRNA-155 were quantified using real-time quantitative polymerase chain reaction.

Results

The plasma levels of miRNA-155 were significantly higher in the CSF group compared to the control group (P < 0.05). In addition, miRNA-155 levels were positively correlated with TFC and high-sensitivity C-reactive protein (hs-CRP) levels (P < 0.05 for both parameters). Multivariate linear regression analysis demonstrated that plasma miRNA-155 (OR = 2.384, 95% confidence interval 1.847–3.273, P = 0.032) and hs-CRP (OR = 1.273, 95% confidence interval 1.036–2.253, P = 0.013) were independent predictors for CSF. Using plasma miRNA-155 levels as the test variable, ROC curve analysis indicated that the area under the curve was 0.782 (P < 0.05).

Conclusion

Patients with CSF have higher plasma levels of miRNA-155, and this may play an important role in the pathogenesis of CSF, and an elevated plasma miRNA-155 level may be a predictor for CSF. A large-scale and multicenter study is required to elucidate the role of miRNA-155 as a potential biomarker for patients with CSF.

Angiotensin II Type 1 Receptor Gene A1166C Polymorphism Was Not Associated With Acute Coronary Syndrome in an Iranian Population

Background

There are very limited data for Iranian populations on the predisposing genetic factors for acute coronary syndrome (ACS).

Objectives

The objective of the present study was to investigate the association of the angiotensin II type 1 receptor (AT1R) gene polymorphism and ACS in an Iranian population.

Patients and Methods

This cross-sectional study was conducted among 263 subjects (97 men and 166 women). Patients (n = 128) aged 30 - 80 years with chest pain were recruited from the emergency department of Ghaem Hospital (Mashhad, Iran). A 12-lead electrocardiograph plus creatine kinase MB (CK-MB) levels were used as the basis for the diagnosis of myocardial ischemia. The control group was selected from age-matched healthy subjects (n = 135). Non-enzymatic kits were used for extraction of DNA from blood samples. Polymerase chain reaction (PCR) was performed to amplify the DNA fragments. For restriction fragment length polymorphism (RFLP) determination, the DdeI enzyme was used to digest the amplified DNA fragments. Statistical analyses were performed using SPSS version 13.0.

Results

There was no statistical difference in the genotype frequency of patients and healthy subjects with regard to age and gender (P > 0.05).

Conclusions

The AT1R A1166C polymorphism appeared not to be associated with the presence of ACS in the population studied.

Endothelial function and germ-line ACE I/D, eNOS and PAI-1 gene profiles in patients with coronary slow flow in the Canakkale population: multiple thrombophilic gene profiles in coronary slow flow

Background

We examined the effects of ACE, PAI-1 and eNOS gene polymorphisms on endothelial function. The genes are related to atherosclerosis and endothelial dysfunction in coronary slow flow (CSF).

Methods

Thirty-three patients with angiographically proven CSF and 48 subjects with normal coronary flow were enrolled in this study. Coronary flow patterns were determined by the thrombolysis in myocardial infarction (TIMI) frame count method. Endothelial function was assessed in the brachial artery by endothelium-dependent flow-mediated dilatation (FMD). PAI-1 4G/5G, eNOS T-786C and ACE I/D polymorphisms were determined by polymerase chain reaction (PCR) amplification.

Results

No difference was found between the groups regarding age, heart rate and blood pressure. Males were more prevalent among patients with CSF than control subjects (58.8 vs 29.8%, p = 0.009). Mean TIMI frame counts were significantly higher in CSF patients (24.2 ± 4.0 vs 13.1 ± 2.5 fpm, p = 0.001). FMD was significantly lower in CSF patients than in the controls (4.9 ± 6.6 vs 7.9 ± 5.6%, p = 0.029). TIMI frame count and FMD were found to be negatively correlated in a correlation analysis (r = –0.269, p = 0.015). PAI-1 4G/5G, eNOS T-786C and ACE I/D polymorphisms were similar in the two groups.

Conclusions

This study showed that endothelial function was impaired in patients with CSF. PAI-1, ACE and eNOS polymorphisms were not related to CSF in our study population.

Intercellular adhesion molecule-1 K469E and angiotensinogen T207M polymorphisms in coronary slow flow

OBJECTIVE

To investigate intercellular adhesion molecule-1 (ICAM1) and angiotensinogen (AGT) gene polymorphisms, as related to atherosclerosis and endothelial dysfunction, in coronary slow flow (CSF).

SUBJECTS AND METHODS

The participants in this study were 48 patients with CSF and 67 patients with normal coronary flow as controls. The K469E polymorphism of ICAM1 (rs5498) and the T207M polymorphism of AGT (rs4762) were determined using the polymerase chain reaction amplification method.

RESULTS

Baseline demographic parameters were similar in both groups. The mean thrombolysis in myocardial infarction frame count was significantly higher in patients with CSF (23.8 ± 5.1) compared to the controls (13.3 ± 2.6, p < 0.001). A significant association was found between the ICAM1 K allele and CSF (OR: 1.96, 95% CI: 1.15-3.35, p = 0.013). There was no difference in the frequency of AGT T207M genotypes in the patients with CSF and the control subjects.

CONCLUSION

This study showed that K469E polymorphisms of ICAM1 that play a role in atherosclerotic pathogenesis are related to CSF.

Endothelial dysfunction and increased carotid intima-media thickness in the patients with slow coronary flow

Flow mediated brachial dilatation (FMD) and carotid intima-media thickness (IMT) have been a surrogate for early atherosclerosis. Slow coronary flow in a normal coronary angiogram is not a rare condition, but its pathogenesis remains unclear. A total of 85 patients with angina were evaluated of their brachial artery FMD, carotid IMT and conventional coronary angiography. Coronary flow was quantified using the corrected thrombosis in myocardial infarction (TIMI) frame count method. Group I was a control with normal coronary angiography (n = 41, 56.1 ± 8.0 yr) and group II was no significant coronary stenosis with slow flow (n = 44, 56.3 ± 10.0 yr). Diabetes was rare but dyslipidemia and family history were frequent in group II. Heart rate was higher in group II than in group I. White blood cells, especially monocytes and homocysteine were higher in group II. The FMD was significantly lower in group II than in group I. Elevated heart rate, dyslipidemia and low FMD were independently related with slow coronary flow in regression analysis. Therefore, endothelial dysfunction may be an earlier vascular phenomenon than increased carotid IMT in the patients with slow coronary flow.

Coronary slow flow phenomenon: a local or systemic disease?

Coronary slow flow phenomenon (CSFP) is an important, angiographic entity characterized by delayed progression of the contrast medium injected into the coronary tree. Since definition of this phenomenon in 1972, there has not been any clear-cut etiology. Original data often focused on histological or pathological changes in coronary artery itself. It was confirmed that small vessel structural defect as well as an underlying residual microvascular resistance abnormality coexists in the coronary microcirculation. Early atherosclerosis was also detected in epicardial coronary arteries by intravascular ultrasound (IVUS). Taken together, it can be suggested that a combination of morphological and functional abnormalities in small vessels and epicardial coronary arteries contributes to the pathogenesis of CSFP. CSFP may be defined as a local disease confined to coronary arteries. However, another feature of CSFP is its frequent occurrence in association with more widespread vascular abnormalities. Reduced endothelial function is implicated in CSFP as measured by flow-mediated dilatation (FMD) of the brachial artery, suggesting that endothelial dysfunction appears to be a generalized process affecting both coronary and peripheral vasculature. In addition, several studies have now demonstrated that carotid intima-media thickness (IMT) is significantly increased in patients with CSFP and there was a significant correlation between coronary intima-media thickness and carotid IMT. Therefore, we hypothesize that CSFP is not an isolated finding but may be part of a systemic vascular disturbance. CSFP is not an infrequently detected finding typically observed in patients presenting with an acute coronary syndrome, usually unstable angina. The subsequent clinical course is characterized by high frequency of relapsing chest pain resulting in considerable impairment in quality of life. Accordingly, further experimental investigations and clinical studies are warranted to shed light into the pathogenesis as well as therapeutics of CSFP.

Asymptomatic Mongolian middle-aged women with high homocysteine blood level and atherosclerotic disease

Growing numbers of studies have shown that hyperhomocysteinemia is an independent, modifiable risk factor for cardiovascular diseases. Hyperhomocysteinemia has been found to be negatively associated with the vitamin B group, especially folate and cobalamin. Because of the relative scarcity of fruits and vegetables in Mongolian foods, and the high cardiovascular diseases rate in Mongolia, we examined homocysteine level and its relation with atherosclerotic change in middle-aged Mongolian women. This cross-sectional study included 79 female asymptomatic residents of Ulaanbaatar, Mongolia. Besides analysis of homocysteine and chemistry tests, participants were interviewed and underwent physical and Doppler ultrasound examination of extracranial vessels. The mean homocysteine level was 9.87 +/- 3.6 micromol/l, and the 2.5th and 97.5th percentiles were 2.2 micromol/l and 19.9 micromol/l. Participants with abnormal Doppler ultrasound finding had significantly higher homocysteine levels (12.8 +/- 4.5 micromol/l vs 8.7 +/- 2.3 micomol/l, P < 0.001) and homocysteine was significantly associated with having atherosclerotic change (odds ratio 2.2, 95% confidence interval = 1.42-3.49, P < 0.001) after adjustment for age, low-density lipoprotein, diastolic blood pressure, and body mass index. Hyperhomocysteinemia was found to be significantly associated with atherosclerotic change in female Mongolian adults. Further studies are necessary to determine factors associated with homocysteine elevation among the Mongolian population.

Angiotensin converting enzyme DD genotype not associated with increased risk of coronary artery disease in the Iranian population

The coronary artery disease (CAD) is of the main causes of heart failure and there is evidence supporting the association of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and the susceptibility to CAD. Therefore, the relevance of ACE polymorphism for CAD was determined in the Iranian population. 487 age-matched individuals including 224 patients with >50% angiographically established coronary stenosis and 263 healthy subjects genotyped for ACE gene I/D polymorphism by a standard method. Paraclinical characteristics including lipid profile were also determined for both groups. While the systolic (p<0.0001) and diastolic (p<0.0001) blood pressure, serum cholesterol (p<0.005) and LDL-C (p<0.05) were significantly increased in CAD patients, our results show that there was no increased risk of CAD in association with DD genotype in Iranian population. Allele frequencies were also similar in both groups. Although, we found a significant difference in ID (p<0.005) and II (p<0.05) genotype between patients and healthy subjects. The present study showed that DD genotype does not increase the CAD susceptibility in the studied Iranian population and may not be as a risk factor. Therefore, further studies together with the other polymorphisms of ACE gene may be required to determine the relation between cardiovascular disease susceptibility and ACE genetic variations in Iranian population.

Insertion/deletion polymorphism of angiotensin converting enzyme gene in Korean hypertensive adolescents

The essential role of the renin-angiotensin system (RAS) in controlling blood pressure has been well established. Genes encoding components of the RAS have been proposed as candidate genes that determine genetic predisposition to hypertension and the risk of developing cardiovascular complications. The purpose of this study was to analyze angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphisms in Korean hypertensive adolescents, and to determine the association between ACE genotype and cardiovascular risk. Forty hypertensive adolescents (16-17 years old, systolic blood pressure (BP) > or =140 mm Hg and/or diastolic BP > or =90 mm Hg) and a control group of twenty normotensive adolescents were included in the study. Obesity index (OI) and body mass index (BMI) were calculated. Skin fold thickness and arm circumference were also measured. Fat mass and fat distribution were analyzed by bioelectrical impedance. Blood pressure was measured at resting state by oscillometric methods. Serum aldosterone, renin, insulin, ACE, homocysteine, vitamin B12, and folate levels were evaluated after a fasting period of 12 h. The carotid intima-media thickness (IMT) and carotid artery diameter were measured by carotid ultrasound. Pulse wave velocity (PWV) and ankle-brachial index (ABI) were also measured. Polymerase chain reaction (PCR) was conducted to amplify DNA from blood samples of each individuals to analyze ACE I/D polymorphism. Genotype frequencies of I/I were 37.5%, I/D 45.0% and D/D 17.5%. Serum ACE levels were 33.5 +/- 8.7 U/l in I/I genotype, 48.6 +/- 19.8 U/l in I/D genotype and 61.4 +/- 22.7 U/l in D/D genotype, which showed that ACE levels were significantly higher in those with D/D or I/D genotype than in I/I genotype. Carotid IMT was significantly greater in D/D group than in I/I group. In conclusion, the D allele is associated with the increased level of ACE in Korean hypertensive adolescents.

Carotid intima-media thickness in pre- and postmenopausal women with suspected coronary artery disease

Carotid intima-media thickness (CIMT) is an early marker of coronary artery disease (CAD). This study aimed to evaluate CIMT value for CAD prediction in pre-and postmenopausal women referred for coronary angiography with angina-like symptoms and a positive result of the treadmill test. The study comprised 321 women referred for coronary angiography with symptoms suggesting CAD. Carotid intima-media thickness was measured in common, bifurcation, and internal carotid artery, and expressed as the mean maximum value. Coronary angiography showed coronary stenosis > or = 50% in 211 (65.7%) women, including 27 with regular menses (47.3 +/- 3.4 years) and 184 postmenopausal (65.8 +/- 7.2 years). Normal coronary arteries were found in 110 women: 17 (47.3 +/- 4.9 years) with regular menses and 93 postmenopausal (64.3 +/- 6.5 years). The highest CIMT values were found in postmenopausal CAD women (1.360 +/- 0.32 mm), as compared to premenopausal with CAD (1.178 +/- 0.36 mm, P = 0.005), pre- (0.860 +/- 0.23 mm, P < 0.001) and postmenopausal (1.022 +/- 0.30 mm, P < 0.001) women without CAD. Carotid intima-media thickness (P < 0.001), hyperlipidemia (P = 0.018), and myocardial infarction (P < 0.001), but not menopause itself or the number of years since menses cessation, were found to be independent CAD predictors. By receiver operating characteristic calculation, the mean maximum CIMT cut-off values discriminating CAD were lower in premenopausal (> or = 0.933 mm) than in postmenopausal women (> or = 1.075 mm; P < 0.05) resulting in similar sensitivity (85.2% and 82.6%) and specificity (70.6% and 69.9%). Carotid intima-media thickness is a strong CAD predictor in both pre- and postmenopausal women, in contrast to the menopausal status.