Rationale and design of the Medical Research Council's Precision Medicine with Zibotentan in Microvascular Angina (PRIZE) trial.

Microvascular angina is caused by cardiac small vessel disease, and dysregulation of the endothelin system is implicated. The minor G allele of the non-coding single nucleotide polymorphism (SNP) rs9349379 enhances expression of the endothelin 1 gene in human vascular cells, increasing circulating concentrations of ET-1. The prevalence of this allele is higher in patients with ischemic heart disease. Zibotentan is a potent, selective inhibitor of the ETA receptor. We have identified zibotentan as a potential disease-modifying therapy for patients with microvascular angina. METHODS: We will assess the efficacy and safety of adjunctive treatment with oral zibotentan (10 mg daily) in patients with microvascular angina and assess whether rs9349379 (minor G allele; population prevalence ~36%) acts as a theragnostic biomarker of the response to treatment with zibotentan. The PRIZE trial is a prospective, randomized, double-blind, placebo-controlled, sequential cross-over trial. The study population will be enriched to ensure a G-allele frequency of 50% for the rs9349379 SNP. The participants will receive a single-blind placebo run-in followed by treatment with either 10 mg of zibotentan daily for 12 weeks then placebo for 12 weeks, or vice versa, in random order. The primary outcome is treadmill exercise duration using the Bruce protocol. The primary analysis will assess the within-subject difference in exercise duration following treatment with zibotentan versus placebo. CONCLUSION: PRIZE invokes precision medicine in microvascular angina. Should our hypotheses be confirmed, this developmental trial will inform the rationale and design for undertaking a larger multicenter trial.

Genetic dysregulation of endothelin-1 is implicated in coronary microvascular dysfunction.

AIMS: Endothelin-1 (ET-1) is a potent vasoconstrictor peptide linked to vascular diseases through a common intronic gene enhancer [(rs9349379-G allele), chromosome 6 (PHACTR1/EDN1)]. We performed a multimodality investigation into the role of ET-1 and this gene variant in the pathogenesis of coronary microvascular dysfunction (CMD) in patients with symptoms and/or signs of ischaemia but no obstructive coronary artery disease (CAD). METHODS AND RESULTS: Three hundred and ninety-one patients with angina were enrolled. Of these, 206 (53%) with obstructive CAD were excluded leaving 185 (47%) eligible. One hundred and nine (72%) of 151 subjects who underwent invasive testing had objective evidence of CMD (COVADIS criteria). rs9349379-G allele frequency was greater than in contemporary reference genome bank control subjects [allele frequency 46% (129/280 alleles) vs. 39% (5551/14380); P = 0.013]. The G allele was associated with higher plasma serum ET-1 [least squares mean 1.59 pg/mL vs. 1.28 pg/mL; 95% confidence interval (CI) 0.10-0.53; P = 0.005]. Patients with rs9349379-G allele had over double the odds of CMD [odds ratio (OR) 2.33, 95% CI 1.10-4.96; P = 0.027]. Multimodality non-invasive testing confirmed the G allele was associated with linked impairments in myocardial perfusion on stress cardiac magnetic resonance imaging at 1.5 T (N = 107; GG 56%, AG 43%, AA 31%, P = 0.042) and exercise testing (N = 87; -3.0 units in Duke Exercise Treadmill Score; -5.8 to -0.1; P = 0.045). Endothelin-1 related vascular mechanisms were assessed ex vivo using wire myography with endothelin A receptor (ETA) antagonists including zibotentan. Subjects with rs9349379-G allele had preserved peripheral small vessel reactivity to ET-1 with high affinity of ETA antagonists. Zibotentan reversed ET-1-induced vasoconstriction independently of G allele status. CONCLUSION: We identify a novel genetic risk locus for CMD. These findings implicate ET-1 dysregulation and support the possibility of precision medicine using genetics to target oral ETA antagonist therapy in patients with microvascular angina. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03193294.

Subjects with microvascular angina have longer GT repeats polymorphism in the haem oxygenase-1 gene promoter.

Objective: Few studies have investigated haem oxygenase-1 gene (HMOX1) promoter polymorphism in microvascular angina (MVA).Materials and methods: HMOX1 promoter (GT)n repeats were examined in healthy controls (N = 220) and MVA subjects (N = 181).Results: The distribution of genotype of SS, SL and LL were significantly different in MVA (17%, 51%, 33%) vs. normal controls (35%, 46%, 20%) (p < 0.001, S allele: ≤30 repeats, L allele: >30 repeats). In multivariate analysis, carrier of L allele (odds ratio 2.772, p < 0.001) was a significant predictor for the diagnosis of MVA.Conclusions: Subjects with MVA had longer HMOX1 promoter (GT)n repeats than the healthy controls. Trial registration number: NCT01198730 at https://clinicaltrials.gov.

Investigation of MTHFR gene C677T polymorphism in cardiac syndrome X patients.

BACKGROUND: Definition of Cardiac Syndrome X (CSX) refers to groups of patients with positive exercise stress test and normal epicardial coronary arteries on coronary angiography accompanied by chest pain. Although the etiology of CSX is not completely understood, there is a common consensus that its pathophysiology may be associated with endothelial dysfunction resulting in impaired coronary flow. Some polymorphisms observed on the MTHFR gene cause inactivation of the MTHFR enzyme, leading to hyperhomocysteinemia and homocysteinuria, which are prominent risk factors of cardiovascular and cerebrovascular diseases. It was aimed to explain the association of the endothelial dysfunction, which is thought to play a role in the pathophysiology of CSX, with C677T polymorphism on MTHFR gene based on genetic basis. METHODS: A total of 176 CSX patients and 196 healthy subjects with similar age and clinical features were compared in terms of C677T polymorphism of the MTHFR gene. RESULTS AND CONCLUSION: There was no significant difference in terms of MTHFR gene C677T polymorphism between CSX patients and controls. When genotypic distribution was compared based on gender in both patients and controls, no significant difference was found between male and female subjects (P>.05). As fasting blood sugar and urea values were significantly higher, alanine aminotransferase and gamma-glutamyl transferase levels were significantly lower in the patients than the controls (P<.05). Described family story of the patients was significantly higher than the controls (P<.05). These suggest that homocysteine metabolism in CSX is not directly related to the endothelial dysfunction and thus the effect on the microvascular circulation.

Association of CYP2C19 variants and epoxyeicosatrienoic acids on patients with microvascular angina.

Categorization as a cytochrome P450 (CYP) 2C19 poor metabolizer (PM) is reported to be an independent risk factor for cardiovascular disease. Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid by CYP2C19 epoxygenases and anti-inflammatory properties, especially in microvascular tissues. We examined the association of CYP2C19 polymorphisms and EETs on microvascular angina (MVA) caused by coronary microvascular dysfunction. We examined CYP2C19 genotypes in patients with MVA (n = 71) and healthy subjects as control (n = 71). MVA was defined as the absence of coronary artery stenosis and epicardial spasms and the presence of inversion of lactic acid levels between intracoronary and coronary sinuses in acetylcholine-provocation test or the adenosine-triphosphate-induced coronary flow reserve ratio was below 2.5. CYP2C19 PM have two loss-of-functon alleles (*2, *3). We measured serum dihydroxyeicosatrienoic acid (DHET) as representative EET metabolite. MVA group showed significantly higher CYP2C19 PM incidence (35% vs. 16%; P = 0.007) and high sense C-reactive protein (hs-CRP) levels (0.127 ± 0.142 vs. 0.086 ± 0.097 mg/dl; P = 0.043) than those of controls. Moreover, in MVA group, hs-CRP levels in CYP2C19 PM were significantly higher than that of non-PM (0.180 ± 0.107 vs. 0.106 ± 0.149 mg/dl, P = 0.045). Multivariate analysis indicated that smoking, hypertension, high hs-CRP, and CYP2C19 PM are predictive factors for MVA. In MVA group, DHET levels for CYP2C19 PM were significantly lower than that of non-PM [10.9 ± 1.64 vs. 14.2 ± 5.39 ng/ml, P = 0.019 (11,12-DHET); 15.2 ± 4.39 vs. 17.9 ± 4.73 ng/ml, P = 0.025 (14,15-DHET)]. CYP2C19 variants are associated with MVA. The decline of EET-based defensive mechanisms owing to CYP2C19 variants may affect coronary microvascular dysfunction.

Association of Low Ficolin-Lectin Pathway Parameters with Cardiac Syndrome X.

In patients with typical angina pectoris, inducible myocardial ischaemia and macroscopically normal coronaries (cardiac syndrome X (CSX)), a significantly elevated plasma level of terminal complement complex (TCC), the common end product of complement activation, has been observed without accompanying activation of the classical or the alternative pathways. Therefore, our aim was to clarify the role of the ficolin-lectin pathway in CSX. Eighteen patients with CSX, 37 stable angina patients with significant coronary stenosis (CHD) and 54 healthy volunteers (HC) were enrolled. Serum levels of ficolin-2 and ficolin-3, ficolin-3/MASP-2 complex and ficolin-3-mediated TCC deposition (FCN3-TCC) were determined. Plasma level of TCC was significantly higher in the CSX than in the HC or CHD group (5.45 versus 1.30 versus 2.04 AU/ml, P < 0.001). Serum levels of ficolin-2 and ficolin-3 were significantly lower in the CSX compared to the HC or CHD group (3.60 versus 5.80 or 5.20 µg/ml, P < 0.05; 17.80 versus 24.10 or 26.80 µg/ml, P < 0.05). The ficolin-3/MASP-2 complex was significantly lower in the CSX group compared to the HC group (92.90 versus 144.90 AU/ml, P = 0.006). FCN3-TCC deposition was significantly lower in the CSX group compared to the HC and CHD groups (67.8% versus 143.3% or 159.7%, P < 0.05). In the CSX group, a significant correlation was found between TCC and FCN3-TCC level (r = 0.507, P = 0.032) and between ficolin-3/MASP-2 complex level and FCN3-TCC deposition (r = 0.651, P = 0.003). In conclusion, in patients with typical angina and myocardial ischaemia despite macroscopically normal coronary arteries, low levels of several lectin pathway parameters were observed, indicating complement activation and consumption. Complement activation through the ficolin-lectin pathway might play a role in the complex pathomechanism of CSX.

Does Inflammation Have a Role in the Pathogenesis of Cardiac Syndrome X? A Genetic-Based Clinical Study With Assessment of Multiple Cytokine Levels.

We compared Turkish patients with cardiac syndrome X (CSX) and controls with respect to serum pro- and anti-inflammatory cytokine levels, as well as the single-nucleotide polymorphisms located in the promoter regions of their related genes. This study included 111 consecutive patients angiographically diagnosed with CSX and 111 healthy controls with similar demographic characteristics. Serum interleukin (IL) 6, tumor necrosis factor α (TNF-α), and IL-10 levels were measured, and the genotypes of the patients and controls were determined using standard methods. Serum IL-6 and IL-10 levels were significantly higher in the CSX group than in the control group (P < .01, respectively). Serum TNF-α level was lower in the CSX group than in the control group (P < .001). On the other hand, participants with CSX and healthy controls were not significantly different with respect to the genotype distributions of IL-6, TNF-α, and IL-10 genes. As a result of our study, both pro-inflammatory and anti-inflammatory cytokines may play a role in the pathogenesis of CSX. In contrast, the studied gene polymorphisms did not influence CSX pathogenesis.

Interleukin-10 promotor -592A/C polymorphism is associated with slow coronary flow in Han Chinese.

An accumulating body of evidence suggests that slow coronary flow (SCF) phenomenon seems to be an early-form of atherosclerosis and low-grade inflammation plays a major role in the atherosclerotic vascular processes. Interleukin (IL)-10 is a multifunctional cytokine involved in both innate and adaptive immune response. The aim of the present study is to investigate the association of IL-10 gene -592A/C polymorphism with SCF in Han Chinese. 250 patients who underwent coronary angiography and had angiographically normal coronary arteries of varying coronary flow rates without any atherosclerotic lesion were enrolled in this study. Patients who had thrombolysis in myocardial infarction frame counts (TFC) above the normal cutoffs were considered to have SCF and those within normal limits were considered to have normal coronary flow (NCF). The PCR-based restriction fragment length polymorphism (PCR-RFLP) technique was used to assess the genotypes frequencies. The distribution of the IL-10 -592A/C genotypes (AA, AC, and CC) was 46.34%, 41.46%, and 12.20% in the NCF group, and 66.51%, 28.71%, and 4.78% in SCF subjects, respectively (P = 0.0280). The frequency of the A allele in the SCF group was significantly higher than that in the NCF group (80.86% vs. 67.07%, P = 0.0054). Compared with the CC genotype, the AA genotype had increased risk of SCF in both unadjusted and adjusted analyses. In SCF patients, the average serum IL-10 levels in AA genotype were statistically lower than in AC + CC genotype (P = 0.0000). These findings suggest that IL-10 -592A/C polymorphism is associated with SCF and the A allele has increased risk for SCF in Han Chinese.

Factor XIII Val34Leu polymorphism in patients with cardiac syndrome X.

BACKGROUND: The aim of the study was to examine the frequency of factor XIII polymorphism among patients with cardiac syndrome X (CSX). METHODS: This study was designed as a cross-sectional and observational study. Forty-eight female patients with CSX and 36 controls matched by age, gender, diabetes, and hypertension were studied. CSX was defined as typical chest pain during rest or effort, abnormal test result for exercise ECG, and presence of angiographically normal epicardial coronary arteries after ruling out inducible spasm. Factor XIII gene polymorphism was investigated by using CVD Strip Assay (ViennaLab Diagnostic GmbH) commercial kit. RESULTS: The frequency of factor XIII (Val/Leu + Leu/Leu) mutation was significantly higher in patients with CSX (43%) than in controls (19%) (p = 0.02). Frequency of the Leu allele was significantly higher in the patient group (23.5% vs. 11.1%, p = 0.04). Factor XIII (Val/Leu + Leu/Leu) mutation (p = 0.01, OR = 3.42; 95% CI 1.22-9.58) and smoking (p = 0.04, OR = 3.33, 95% CI 1.05-10.58) were identified as independent predictors of the disease in multivariate regression analysis. CONCLUSIONS: This study indicates that there is an evidence for association between factor XIII Val34Leu polymorphism and CSX.

Intron 4 VNTR polymorphism of eNOS gene is protective for cardiac syndrome X.

Microvascular abnormalities caused by endothelial dysfunction seem to be responsible for the myocardial ischemia in patients with cardiac syndrome X (CSX). Nitric oxide is a key mediator of endothelial function and is synthesized by endothelial nitric oxide synthase (eNOS). We investigated if the 3 potential polymorphisms of the eNOS gene (VNTR in intron 4, T786C polymorphism in the promoter region, and G894T polymorphism in exon 7) are independent risk factors for CSX. Sixty-nine patients with CSX and 73 healthy controls were studied. Genotypes were determined through polymerase chain reaction with or without restriction endonuclease digestions. Genotype distribution was significantly different between patients with CSX and controls for intron 4aa (allele for 4 repeats of 27 bp), intron 4aa genotype frequency being 3.2% and 6.8%, respectively. The presence of intron 4a is 3.2 (odds ratio) times protective (95% confidence interval, 1.5-6.8) for the risk of CSX disease. The protective effect of intron 4a polymorphism also holds after adjustment for age and sex and when the study group is limited to those without hypertension and hyperlipidemia. No significant difference was observed in genotype distribution of G894T and T786C polymorphism between patients with CSX and controls. In conclusion, intron 4aa genotype of eNOS gene is protective for CSX. No association was found between promoter and exon 7 polymorphisms of eNOS gene and CSX.

Gene expression of kinin receptors B1 and B2 in PBMC from patients with cardiac syndrome X.

INTRODUCTION: Cardiac syndrome X (CSX) is defined by typical chest pain, ST segment depression on ECG and normal coronary angiography. Pathology of CSX may involve microvascular dysfunction related to inflammation and abnormal pain sensitivity. Kinins are labile peptides participating in vasodilation, inflammation and pain. Their effects are mediated by two receptors: B1 and B2. The aim of the study was to assess gene expression of kinin receptors in peripheral blood mononuclear cells (PBMC) from patients with CSX. METHODS: The study was carried out in 34 patients with cardiac syndrome X, 13 with unstable angina and ten healthy subjects. Total mRNA was extracted from PBMC and the number of mRNA copies was assessed by quantitive reverse transcriptase polymerase chain reaction. RESULTS AND CONCLUSION: The study showed 7-fold higher transcriptional activity of B1R in CSX vs. control and 3.5 higher vs. UA. B2R expression was 2.5-fold higher in CSX group vs. control and UA, while in the letter two groups it was similar. Such disturbance in kinin signaling may participate in local vasoconstriction and may reflect disturbances in kinin signaling leading to nociceptive disturbances in these patients.

Endothelial cell dysfunction in women with cardiac syndrome X and MTHFR C677T mutation.

BACKGROUND: The etiology of chest pain with normal epicardial coronary arteries (cardiac syndrome X) seems to be related to endothelial cell dysfunction. Multiple factors are implicated in the pathophysiology, including elevated levels of homocysteine in the blood. Mutations in the MTHFR gene are associated with elevated levels of homocysteine. OBJECTIVES: To test whether abnormal homocysteine metabolism is associated with syndrome X. METHODS: Forty-two women with chest pain, positive stress test and normal coronary arteries (syndrome X) and 100 asymptomatic women (controls) were studied for the C677T mutation. Vitamin B12, folic acid, and plasma levels of homocysteine were also measured. Endothelial cell function was studied in 10 patients with syndrome X and homozygosity for C677T mutation, and in 10 matched healthy controls. Folic acid (5 mg daily) was prescribed to syndrome X patients after initial measurements of ECF. Following 13 weeks of treatment, ECF and blood tests were repeated and compared to baseline measurements. RESULTS: Homozygosity for C677T mutation was doubled in syndrome X vs. control (33%, 14/42 vs. 16%, 16/100, P < 0.02), and homocysteine levels were increased (9.16 +/- 2.4 vs. 8.06 +/- 2.6 pmol/L, P = 0.02). In the 10 homozygous patients, homocysteine levels decreased significantly after treatment with 5 mg/day folic acid (10 +/- 3.3 vs. 5.4 +/- 1.1 micromol/L, P = 0.004). Abnormal baseline ECF improved after treatment with folic acid: flow-mediated dilatation was greater (11.3 +/- 7.9% vs. 0.7 +/- 4.5%, P < 0.002), as was nitroglycerin-mediated dilatation (15.2 +/- 9.0% vs. 5.6 +/- 6.4%, P < 0.003). Frequency of chest pain episodes was significantly reduced after 13 weeks of folic acid treatment. CONCLUSION: Our findings establish the association between the C677Tmutation, endothelial cell dysfunction and cardiac syndrome X, and provide a novel and simple therapy for a subset of patients with syndrome X and homozygosity for the C677T mutation.

Increased lymphocyte deoxyribonucleic acid damage in patients with cardiac syndrome X.

OBJECTIVES: To investigate whether there is lymphocyte deoxyribonucleic acid (DNA) damage in patients with cardiac syndrome X (CSX), and its relation with total antioxidant status (TAS), inflammation and ischemia. METHODS: Twenty-three patients with CSX, 21 patients with non-CSX (NCSX) and 20 healthy volunteers were included in the study. Lymphocyte DNA damage (Arbitrary Unit) was assessed by alkaline single cell electrophoresis (comet) assay in peripheral lymphocyte, and plasma levels of TAS (mmol Trolox equiv./l) were determined using a novel automated measurement method. High sensitive C-reactive protein (hsCRP) and other biochemical parameters were measured from all subjects. Treadmill exercise test and coronary angiography were performed to CSX and NCSX groups. RESULTS: Lymphocyte DNA damage was increased in patients with CSX compared with NCSX and control group (p<0.001, for both). Also, TAS was decreased, and hsCRP was increased in CSX compared with NCSX and control group (p<0.001, for all). Lymphocyte DNA damage was correlated with magnitude of ST depression (p=0.034), hsCRP (p=0.001), TAS (p<0.001) and presence of diabetes (p=0.022) in bivariate analysis. In multiple linear regression analysis, lymphocyte DNA damage was correlated with only TAS (beta=-0.413, p=0.017) and hsCRP (beta=0.414, p=0.006). CONCLUSION: Lymphocyte DNA damage was increased in patients with CSX. The increase in lymphocyte DNA damage may be related with increased oxidative stress and inflammation in patients with CSX.

Gene polymorphisms predisposing to cardiac hypertrophy in patients with cardiac syndrome X.

Polymorphisms of the angiotensin-converting enzyme gene and endothelial nitric oxide synthase gene have been suggested to be associated with left ventricular hypertrophy. The aim of our study was to asses the association between above polymorphisms and left ventricular hypertrophy in patients with cardiac syndrome X. The presence of allele 4 of eNOS VNTR polymorphism could predispose to cardiac hypertrophy. The pathological course of postprandial lipemia in patients with CSX may add to the understanding of the CSX pathology.

Vasospastic angina and microvascular angina are differentially influenced by PON1 A632G polymorphism in the Japanese.

BACKGROUND: Ethnicity and smoking are well-known risk factors for the pathogenesis of coronary vasospasm. Oxidative stress induced by smoking plays a crucial role in coronary vasospasm, but is not enough to account for the pathogenesis of coronary vasospasm, indicating that genetic factors are strongly involved. METHODS AND RESULTS: The study group comprised 162 vasospastic angina patients (VSAs), 61 microvascular angina patients (MVAs) and 61 non-responders (NRs) diagnosed by acetylcholine provocation test. Four polymorphisms of the oxidative stress related genes, cytochrome b-245, alpha polypeptide gene (CYBA) C242T and A640G, paraoxonase 1 gene (PON1) A632G, phospholipase A2 group VII gene (PLA2G7) G994T were genotyped. Allele frequency of PON1 632-G was significantly higher in both the VSA with dominant fashion and the MVA with recessive fashion compared with NR. This association was strongly influenced by gender in the MVA only. There were no significant associations between the other polymorphisms and coronary vasospasm. In addition, the allele frequency of PON1 632-G in the Japanese was higher than in Caucasians. CONCLUSIONS: There was a significant association between PON1 A632G polymorphism and MVA as well as VSA, but the impact of this on VSA and MVA is different in the Japanese.

Angiotension-converting enzyme gene I/D polymorphism in patients with angina and normal coronary arteriograms.

A polymorphism of the human angiotensin-converting enzyme (ACE) gene has been identified in which the insertion (I) rather than the deletion (D) variant is associated with lower circulating and tissue ACE activity. ACE I allele is associated with resistance and endurance performance. Skeletal muscle metabolic efficiency is reduced in patients with heart failure and is improved by ACE inhibition. Profound muscle fatigue is a predominant and debilitating symptom in a proportion or patients with angina and normal coronary arteriograms (ANCA), and we postulated that the gene D allele might be associated with the presence of fatigue in ANCA patients. We studied 33 consecutive patients with typical ANCA who completed a validated fatigue questionnaire, and found an excess of the D allele frequency in patients with the highest fatigue scores compared to those with the lowest (64% vs. 36%; p=0.027).

Distinct psychosocial differences between women with coronary heart disease and cardiac syndrome X.

AIMS: To compare the impact of oestrogen, gynaecological history, social support, life events and family history of CHD on psychosocial morbidity in syndrome X, CHD patients and healthy controls. METHODS AND RESULTS: 100 female syndrome X (60 +/- 9 years), 100 female CHD (65 +/- 9 years) and 100 healthy female volunteers (61 +/- 10 years) completed the hospital anxiety and depression scale (HADS), health anxiety questionnaire (HAQ), a demographic information scale, life events scale, family history of CHD, menopausal, menstrual and gynaecological history. A 17beta-oestradiol sample was taken. Syndrome X patients had higher levels of life interference (p < 0.05) and HADS anxiety (p < 0.05) than CHD patients, and higher levels of all HADS and HAQ scales than controls (p < 0.01). Syndrome X patients with a large social network had lower HADS anxiety (p < 0.05), health worry (p < 0.05), life interference (p < 0.01) and total HAQ (p < 0.01). Social network (p = 0.003), divorced/separated or widowed status (p = 0.005), HRT (p = 0.008) and HADS anxiety score (p < 0.001) accounted for 41.9% of the variance in HAQ scores in syndrome X. Oestrogen was unrelated to the HADS or HAQ for any group. CONCLUSION: Syndrome X patients suffered higher levels of psychological morbidity in comparison to CHD patients and controls. Life events and social network size were related to health anxiety, general anxiety and depression in women with syndrome X.

[Relations between endothelial nitric oxide synthase and angiotensin-converting gene polymorphisms and certain biochemical parameters in patients with cardiac syndrome X]. / Zwiazek miedzy polimorfizmem genu dla sródblonkowej syntazy tlenku azotu oraz dla konwertazy angiotensyny a wybranymi parametrami biochemicznymi u pacjentów z kardiologicznym zespolem X.

Cardiological syndrome X (CSX) is defined as effort anginal pain, positive exercise tolerance test and absence of angiographically documented stenosis in coronary arteries. Some genetic predispositions and metabolic disturbances can participate in development of this syndrome. The aim of our study was to investigate the associations between some biochemical parameters and polymorphism of ACE and eNOS (VNTR and Glu298Asp) genes in patients with CSX. 36 patients with CSX and a control group of 30 healthy volunteers were included in the study. The genotypes were determined by the polymerase chain reaction. Our study revealed that patients with CSX exerted lower fasting NOx levels, tended to have higher insulin values measured at 1 h of oral glucose tolerance test and higher levels of triglycerides and free fatty acids during oral lipid tolerance test. Patients with genotype T/T Glu298Asp of eNOS and 4/4 VNTR of eNOS revealed lower levels of NOx compared to patients with genotypes G/G and 5/5, respectively (30.5 +/- 7.2 vs 13.2 +/- 4.5; 28.6 +/- 8.4 vs 14.2 +/- 7.4; p<0.05). Thus, we conclude that disturbances in free fatty acid utilization, estimated by postprandial lipaemic test play important roles in the development of endothelial injury in CSX.

Nitric oxide synthase gene G298 allele. Is it a marker for microvascular angina in hypertensive patients?

BACKGROUND: Nitric oxide (NO) has an important effect on blood pressure, arterial wall, and the basal release of endothelial NO in hypertension (HPN) may be reduced. Until now, there is no solid data revealing the potential role of the polymorphism of the nitric oxide synthase gene (NOS) in patients with HPN and microvascular angina. AIM: The aim of the present study is to investigate the gene of endothelial nitric oxide synthase (eNOS), as the polymorphism of this gene may be a putative candidate for HPN and initiate the process of atherosclerosis. METHODS: Sixty participants were recruited for this study; 50 were hypertensive patients complaining of chest pain [30 of them have electrocardiogram (EKG) changes of ischemia], 20 had isolated HPN, and 10 healthy volunteers served as control. All patients underwent stress myocardial perfusion imaging (MPI) and coronary angiography. Genotyping of eNOS for all patients and controls was performed. The linkages between HPN, microvascular angina and eNOS gene polymorphism were investigated. RESULTS: MPI and coronary angiography revealed that 15 patients had chest pain with true ischemia and reversible myocardial perfusion defects (multiple and mild) but normal epicardial coronary arteries (microvascular angina), while 15 patients had significant coronary artery disease (CAD), and 20 hypertensive patients showed normal perfusion scan and coronary angiography. The prevalence of the NOS G(298) allele was higher in the hypertensive group with microvascular angina (documented by MPI) than it was among the control participants (P<.005). The eNOS allele was significantly higher in the hypertensive group than in the control participants, but there was no significant difference in homozygote mutants among hypertensive participants, x-syndrome and patients with CAD. CONCLUSION: eNOS gene polymorphism is proved to be an important etiology in microvascular angina (x-syndrome) among hypertensive patients. In addition, the eNOS mutant gene showed a significant increase in isolated HPN and in patients with CAD.