TNF-α receptor 1 knockdown in the subfornical organ ameliorates sympathetic excitation and cardiac hemodynamics in heart failure rats.

In systolic heart failure (HF), circulating proinflammatory cytokines upregulate inflammation and renin-angiotensin system (RAS) activity in cardiovascular regions of the brain, contributing to sympathetic excitation and cardiac dysfunction. Important among these is the subfornical organ (SFO), a forebrain circumventricular organ that lacks an effective blood-brain barrier and senses circulating humors. We hypothesized that the tumor necrosis factor-α (TNF-α) receptor 1 (TNFR1) in the SFO contributes to sympathetic excitation and cardiac dysfunction in HF rats. Rats received SFO microinjections of a TNFR1 shRNA or a scrambled shRNA lentiviral vector carrying green fluorescent protein, or vehicle. One week later, some rats were euthanized to confirm the accuracy of the SFO microinjections and the transfection potential of the lentiviral vector. Other rats underwent coronary artery ligation (CL) to induce HF or a sham operation. Four weeks after CL, vehicle- and scrambled shRNA-treated HF rats had significant increases in TNFR1 mRNA and protein, NF-κB activity, and mRNA for inflammatory mediators, RAS components and c-Fos protein in the SFO and downstream in the hypothalamic paraventricular nucleus, along with increased plasma norepinephrine levels and impaired cardiac function, compared with vehicle-treated sham-operated rats. In HF rats treated with TNFR1 shRNA, TNFR1 was reduced in the SFO but not paraventricular nucleus, and the central and peripheral manifestations of HF were ameliorated. In sham-operated rats treated with TNFR1 shRNA, TNFR1 expression was also reduced in the SFO but there were no other effects. These results suggest a key role for TNFR1 in the SFO in the pathophysiology of systolic HF.NEW & NOTEWORTHY Activation of TNF-α receptor 1 in the subfornical organ (SFO) contributes to sympathetic excitation in heart failure rats by increasing inflammation and renin-angiotensin system activity in the SFO and downstream in the hypothalamic paraventricular nucleus. Cytokine receptors in the SFO may be a target for central intervention in cardiovascular conditions characterized by peripheral inflammation.

Mitochondrial Aldehyde Dehydrogenase 2 Regulates Revascularization in Chronic Ischemia: Potential Impact on the Development of Coronary Collateral Circulation.

OBJECTIVE: Revascularization is an essential process to compensate for cardiac underperfusion and, therefore, preserves cardiac function in the face of chronic ischemic injury. Recent evidence suggested a vital role of aldehyde dehydrogenase 2 (ALDH2) in cardiac protection after ischemia. This study was designed to determine whether ALDH2 regulates chronic ischemia-induced angiogenesis and to explore the underlying mechanism involved. Moreover, the clinical impact of the ALDH2 mutant allele on the development of coronary collateral circulation (CCC) was evaluated. APPROACH AND RESULTS: Mice limb ischemia was performed. Compared with wild-type, ALDH2 deletion significantly reduced perfusion recovery, small artery and capillary density, and increased muscle atrophy in this ischemic model. In vitro, ALDH2-knockdown reduced proliferation, migration and hypoxia triggered endothelial tube formation of endothelial cells, the effects of which were restored by ALDH2 transfection. Further examination revealed that ALDH2 regulated angiogenesis possibly through hypoxia-inducible factor-1α/vascular endothelial growth factor pathways. To further discern the role of ALDH2 deficiency in the function of bone marrow stem/progenitor cells, cross bone marrow transplantation was performed between wild-type and ALDH2-knockout mice. However, there was no significant improvement for wild-type bone marrow transplantation into knockout mice. ALDH2 genotyping was screened in 139 patients with chronic total occlusion recruited to Zhongshan Hospital (2011.10-2014.4). Patients with poor CCC (Rentrop 0-1; n=51) exhibited a higher frequency of the AA genotype than those with enriched CCC (Rentrop 2-3; n=88; 11.76% versus 1.14%; P=0 0.01). However, the AA group displayed less enriched CCC frequency in Logistic regression model when compared with the GG group (odds ratio=0.08; 95% confidence interval, 0.009-0.701; P=0 0.026). Furthermore, serum vascular endothelial growth factor level tended to be lower in patients with ALDH2 mutation. CONCLUSIONS: This study demonstrated that ALDH2 possesses an intrinsic capacity to regulate angiogenesis via hypoxia-inducible factor-1α and vascular endothelial growth factor. Patients with ALDH2-deficient genotype displayed a higher risk of developing poor CCC. Therapeutic individualization based on ALDH2 allele distribution may thus improve the therapeutic benefit, especially in the East Asian decedents.

786T/c endothelial nitric oxide synthase gene polymorphism and coronary collateral circulation.

INTRODUCTION: In this study, we investigated the association between -786T/C polymorphism of the endothelial nitric oxide (NOS3) gene in which thymidine is replaced by a cytosine at nucleotide -786 (rs 2070744) and coronary collateral circulation (CCC) in patients with stable coronary artery disease. MATERIALS AND METHODS: 286 patients having a critical stenosis (> 95%) in at least one major epicardial coronary vessel were included in the study. CCC was defined according to the Rentrop classification (R). Patients with R0-1 CCC were included in the poor CCC group and subjects with R2-3 CCC were assigned to the good CCC group. The polymerase chain reaction method was used for genotyping. 152 patients with poor CCC and 134 patients with good CCC were examined. RESULTS: The frequency of cytosine-cytosine (CC) and thymidine-cytosine (TC) genotypes and allele C were higher in the poor CCC group, but the difference did not reach statistical significance. In the dominant model, the frequency of CC+TC vs. thymidine-thymidine (TT) genotypes was significantly higher in the poor CCC group (67.1% vs. 54.5%, respectively; χ²=4.78; p=0.02). In multivariate regression analysis, the dominant model for -786T/C polymorphism of the NOS3 gene remained as an independent correlate of poor CCC. DISCUSSION: -786T/C polymorphism of the NOS3 gene (rs 2070744) may be associated with poor angiogenesis and the development of CCC in stable coronary artery disease.

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.

Coronary vasospasm induced in transgenic mouse with increased phospholipase C-δ1 activity.

BACKGROUND: We reported that phospholipase C (PLC)-δ1 activity was enhanced 3-fold in patients with coronary spastic angina. We detected variant PLC-δ1 with replacement of arginine 257 by histidine (R257H) showing increased enzymatic activity. We tested the hypothesis that increased PLC-δ1 activity causes enhanced coronary vasomotility. METHODS AND RESULTS: We generated transgenic (TG) mice with human R257H variant PLC-δ1 in vascular smooth muscle cells. PLC enzymatic activity in the coronary artery was increased by 2.57 and 1.89 times, respectively, in homozygous and heterozygous TG compared with wild-type (WT) mice. ST elevation after ergometrine occurred in 17 of 18 homozygous TG, 6 of 20 heterozygous TG, and 3 of 22 WT mice (P<0.01, homozygous TG versus WT; P<0.05, homozygous TG versus heterozygous TG; P=NS, heterozygous TG versus WT). ST elevation was associated with bradyarrhythmias in homozygous TG mice. Focal coronary artery narrowing was documented with the microvascular filling technique in 3 of 5 homozygous TG mice after ergometrine but not in any of 7 WT mice (P<0.05). In the isolated Langendorff hearts, coronary perfusion pressure was increased after ergometrine in homozygous TG mice (P<0.01) but not in heterozygous TG or WT mice. Coronary perfusion pressure increase after prostaglandin F2α was similar among homozygous TG, heterozygous TG, and WT mice. Cultured rat aortic smooth muscle cells transfected with variant PLC-δ1 showed a higher PLC activity than those with WT PLC-δ1 (P<0.05) and furthermore showed greater intracellular Ca2+ response to acetylcholine in variant than in WT PLC-δ1 (P<0.05). CONCLUSIONS: Increased PLC-δ1 activity enhances coronary vasomotility such as that seen in patients with coronary spastic angina.

Role of genetic polymorphisms of ion channels in the pathophysiology of coronary microvascular dysfunction and ischemic heart disease.

Conventionally, ischemic heart disease (IHD) is equated with large vessel coronary disease. However, recent evidence has suggested a role of compromised microvascular regulation in the etiology of IHD. Because regulation of coronary blood flow likely involves activity of specific ion channels, and key factors involved in endothelium-dependent dilation, we proposed that genetic anomalies of ion channels or specific endothelial regulators may underlie coronary microvascular disease. We aimed to evaluate the clinical impact of single-nucleotide polymorphisms in genes encoding for ion channels expressed in the coronary vasculature and the possible correlation with IHD resulting from microvascular dysfunction. 242 consecutive patients who were candidates for coronary angiography were enrolled. A prospective, observational, single-center study was conducted, analyzing genetic polymorphisms relative to (1) NOS3 encoding for endothelial nitric oxide synthase (eNOS); (2) ATP2A2 encoding for the Ca²âº/H⁺-ATPase pump (SERCA); (3) SCN5A encoding for the voltage-dependent Na⁺ channel (Nav1.5); (4) KCNJ8 and KCNJ11 encoding for the Kir6.1 and Kir6.2 subunits of K-ATP channels, respectively; and (5) KCN5A encoding for the voltage-gated K⁺ channel (Kv1.5). No significant associations between clinical IHD manifestations and polymorphisms for SERCA, Kir6.1, and Kv1.5 were observed (p > 0.05), whereas specific polymorphisms detected in eNOS, as well as in Kir6.2 and Nav1.5 were found to be correlated with IHD and microvascular dysfunction. Interestingly, genetic polymorphisms for ion channels seem to have an important clinical impact influencing the susceptibility for microvascular dysfunction and IHD, independent of the presence of classic cardiovascular risk factors.

Hearts of hypoxia-inducible factor prolyl 4-hydroxylase-2 hypomorphic mice show protection against acute ischemia-reperfusion injury.

Hypoxia-inducible factor (HIF) has a pivotal role in oxygen homeostasis and cardioprotection mediated by ischemic preconditioning. Its stability is regulated by HIF prolyl 4-hydroxylases (HIF-P4Hs), the inhibition of which is regarded as a promising strategy for treating diseases such as anemia and ischemia. We generated a viable Hif-p4h-2 hypomorph mouse line (Hif-p4h-2(gt/gt)) that expresses decreased amounts of wild-type Hif-p4h-2 mRNA: 8% in the heart; 15% in the skeletal muscle; 34-47% in the kidney, spleen, lung, and bladder; 60% in the brain; and 85% in the liver. These mice have no polycythemia and show no signs of the dilated cardiomyopathy or hyperactive angiogenesis observed in mice with broad spectrum conditional Hif-p4h-2 inactivation. We focused here on the effects of chronic Hif-p4h-2 deficiency in the heart. Hif-1 and Hif-2 were stabilized, and the mRNA levels of glucose transporter-1, several enzymes of glycolysis, pyruvate dehydrogenase kinase 1, angiopoietin-2, and adrenomedullin were increased in the Hif-p4h-2(gt/gt) hearts. When isolated Hif-p4h-2(gt/gt) hearts were subjected to ischemia-reperfusion, the recovery of mechanical function and coronary flow rate was significantly better than in wild type, while cumulative release of lactate dehydrogenase reflecting the infarct size was reduced. The preischemic amount of lactate was increased, and the ischemic versus preischemic [CrP]/[Cr] and [ATP] remained at higher levels in Hif-p4h-2(gt/gt) hearts, indicating enhanced glycolysis and an improved cellular energy state. Our data suggest that chronic stabilization of Hif-1alpha and Hif-2alpha by genetic knockdown of Hif-p4h-2 promotes cardioprotection by induction of many genes involved in glucose metabolism, cardiac function, and blood pressure.

Adenosine A2(A) receptor gene polymorphism (1976C>T) affects coronary flow reserve response during vasodilator stress testing in patients with non ischemic-dilated cardiomyopathy.

OBJECTIVES: Patients with non ischemic-dilated cardiomyopathy (DCM) are characterized by an activation of the adenosinergic system and reduced coronary flow reserve (CFR) evaluated by transthoracic Doppler echocardiography during vasodilator adenosinergic stress (dipyridamole administration). The aim of this study was to assess whether genetic polymorphisms (263C>T and 1976C>T) of the A2(A) receptor gene affect CFR response in patients with DCM. METHODS: We enrolled a group of 80 patients with DCM (55 male; age, 62±10.3 years) and 162 healthy volunteers (55 male; age, 45.1±9.5 years). Doppler-derived CFR (high-dose dipyridamole coronary diastolic peak flow velocity to resting coronary peak flow velocity ratio) of distal left anterior descending artery was determined in DCM. A2(A) receptor genotyping was determined in all patients by polymerase chain reaction-restriction fragment length polymorphism analysis. The expression of A2(A) protein and mRNA was also assessed in healthy controls. RESULTS: The genotype distribution of the 263C>T (P=0.5) and 1976C>T (P=0.8) polymorphisms was not significantly different between patients and controls. Patients with 1976TT genotype had significantly lower CFR value than 1976CC patients (2.3±0.7, 2.0±0.5 and 1.9±0.4, P<0.05 for CC, CT and TT genotypes, respectively). Controls who were heterozygous (P=0.02) or homozygous (P=0.001) for the T1976 allele showed a significant increase in A2(A) receptor protein. CONCLUSION: These data demonstrate that A2(A) 1976C>T polymorphism is associated with a blunted coronary vasodilatory response in patients with DCM, and support a direct consequences of this single nucleotide polymorphism for protein expression. Additional studies are needed to better define the functional role of this genetic variant as well as to clarify the potential clinical impact of genetics during pharmacological stress cardiac imaging.

Non-cell-autonomous roles for the planar cell polarity gene Vangl2 in development of the coronary circulation.

Establishment of cellular polarity is essential for the development of many tissues. In this study, we describe defects in the formation of the coronary vasculature in the loop-tail (Lp) mutant in which the planar cell polarity (PCP) gene, Vangl2, is disrupted. Although Vangl2 is expressed exclusively in the myocardial cells of the developing heart, the coronary vessels do not develop an intact smooth muscle layer, and there are enlarged, ectopic vessels on the surface of the heart. Reduced fibronectin deposition in the subepicardial space is associated with limited migration of epicardially derived cells (EPDCs) into the ventricular myocardium and likely contributes to these defects. Analysis of cardiomyocytes shows that the actin cytoskeleton is disrupted and the cytoarchitecture of the ventricular myocardium is abnormal in Lp/Lp hearts. Moreover, activation of RhoA/Rho kinase signaling is disrupted in these cells. Conditional inhibition of myocardial Rho kinase activity disrupts the organization of the cardiomyocytes and formation of the coronary vessels to produce the same spectrum of defects as seen in Lp. These data suggest that Vangl2 and Rho kinase act cell autonomously in the myocardium to regulate the organization of cardiomyocytes but also have non-cell-autonomous effects on the formation of the coronary vasculature.

Smooth muscle protein 22alpha-mediated patchy deletion of Bmpr1a impairs cardiac contractility but protects against pulmonary vascular remodeling.

Vascular expression of bone morphogenetic type IA receptor (Bmpr1a) is reduced in lungs of patients with pulmonary arterial hypertension, but the significance of this observation is poorly understood. To elucidate the role of Bmpr1a in the vascular pathology of pulmonary arterial hypertension and associated right ventricular (RV) dysfunction, we deleted Bmpr1a in vascular smooth muscle cells and in cardiac myocytes in mice using the SM22alpha;TRE-Cre/LoxP;R26R system. The LacZ distribution reflected patchy deletion of Bmpr1a in the lung vessels, aorta, and heart of SM22alpha;TRE-Cre;R26R;Bmpr1a(flox/+) and flox/flox mutants. This reduction in BMPR-IA expression was confirmed by Western immunoblot and immunohistochemistry in the flox/flox group. This did not affect pulmonary vasoreactivity to acute hypoxia (10% O2) or the increase in RV systolic pressure and RV hypertrophy following 3 weeks in chronic hypoxia. However, both SM22alpha;TRE-Cre;R26R;Bmpr1a(flox/+) and flox/flox mutant mice had fewer muscularized distal pulmonary arteries and attenuated loss of peripheral pulmonary arteries compared with age-matched control littermates in hypoxia. When Bmpr1a expression was reduced by short interference RNA in cultured pulmonary arterial smooth muscle cells, serum-induced proliferation was attenuated explaining decreased hypoxia-mediated muscularization of distal vessels. When Bmpr1a was reduced in cultured microvascular pericytes by short interference RNA, resistance to apoptosis was observed and this could account for protection against hypoxia-mediated vessel loss. The similar elevation in RV systolic pressure and RV hypertrophy, despite the attenuated remodeling with chronic hypoxia in the flox/flox mutants versus controls, was not a function of elevated left ventricular end diastolic pressure but was associated with increased periadventitial deposition of elastin and collagen, potentially influencing vascular stiffness.

Impact of ACE and ApoE polymorphisms on myocardial perfusion: correlation with myocardial single photon emission computed tomographic imaging.

Coronary artery disease is associated with multiple genetic and environmental risk factors. In this study, we evaluated the correlation of angiotensin l-converting enzyme (ACE) (I/D) and ApoE gene polymorphisms (E2, E3, E4 and g.-219G/T) with myocardial perfusion. We examined 410 patients using exercise-rest myocardial perfusion single photon emission computed tomography (SPECT), in which the summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS) indexes were calculated. Homozygotes for the ACE D allele had greater mean values of SSS (P<0.001) and SDS (P<0.001). In addition, E3 homozygotes, E4 heterozygotes and E4 homozygotes had significantly higher values of SSS and SDS compared with E3 heterozygotes (P<0.001); E4 homozygotes had significantly higher values of SSS and SDS compared with E3 homozygotes. Furthermore, for the g.-219G>T polymorphic site at the promoter region of ApoE gene, the mean values of SSS and SDS were significantly higher for T heterozygotes/homozygotes than for GG homozygotes. Adjusting for all demographic and clinical data using multiple linear regression analysis it was found that ACE D and both ApoE genotypes were independent predictors with a cumulative contribution for the prediction of SSS and SDS. Furthermore, logistic regression analysis revealed that all three genotypes had an independent predictive ability for abnormal SSS (SSS>2). These data provide the first evidence of an association and significant cumulative contribution of the aforementioned genotypes in myocardial perfusion with E4 allele having the strongest association followed by ACE D and ApoE g.-219T alleles.

Therapeutic angiogenesis with intramuscular NV1FGF improves amputation-free survival in patients with critical limb ischemia.

This study evaluated the efficacy and safety of intramuscular administration of NV1FGF, a plasmid-based angiogenic gene delivery system for local expression of fibroblast growth factor 1 (FGF-1), versus placebo, in patients with critical limb ischemia (CLI). In a double-blind, randomized, placebo-controlled, European, multinational study, 125 patients in whom revascularization was not considered to be a suitable option, presenting with nonhealing ulcer(s), were randomized to receive eight intramuscular injections of placebo or 2.5 ml of NV1FGF at 0.2 mg/ml on days 1, 15, 30, and 45 (total 16 mg: 4 x 4 mg). The primary end point was occurrence of complete healing of at least one ulcer in the treated limb at week 25. Secondary end points included ankle brachial index (ABI), amputation, and death. There were 107 patients eligible for evaluation. Improvements in ulcer healing were similar for use of NV1FGF (19.6%) and placebo (14.3%; P = 0.514). However, the use of NV1FGF significantly reduced (by twofold) the risk of all amputations [hazard ratio (HR) 0.498; P = 0.015] and major amputations (HR 0.371; P = 0.015). Furthermore, there was a trend for reduced risk of death with the use of NV1FGF (HR 0.460; P = 0.105). The adverse event incidence was high, and similar between the groups. In patients with CLI, plasmid-based NV1FGF gene transfer was well tolerated, and resulted in a significantly reduced risk of major amputation when compared with placebo.

The relationship between slow coronary flow and angiotensin converting enzyme and ATIIR1 gene polymorphisms.

OBJECTIVES: Endothelial dysfunction in coronary arteries is the main pathogenetic mechanism in patients with slow coronary flow (SCF). Angiotensin converting enzyme (ACE) gene polymorphism has important effects on endothelial function. However, angiographic studies investigating the relation between the ACE and angiotensin II type 1 receptor (ATIIR1) insertion (I)/deletion (D) polymorphism and SCF is limited. METHODS: Fifty-four patients with normal coronary arteries documented by coronary angiography with SCF in any coronary vessel, and 22 subjects with normal coronary arteries without SCF were included in this study. The ID (I/D), II, and DD genotypes were examined. RESULTS: Frequency of DD genotype was found higher in SCF group (50% vs. 27%, respectively; p = .055). Frequency of D allele was significantly higher in the SCF group (p < .05). Presence of DD genotypes increased the possibility of SCF 5.25 times compared to absence of DD genotype (OR, 5.25; 95% CI, 1.30-21.38, p < .05). There was no significant correlation of ATIIR1 gene polymorphism between the 2 groups. CONCLUSIONS: We demonstrated that DD genotype is a risk factor for SCF. Determination of ACE gene polymorphism in patients with SCF may be helpful in medical management and risk stratification.

Structural stability of neoangiogenic intramyocardial microvessels supports functional recovery in chronic ischemic myocardium.

We hypothesize that combining angiopoietin-1 (ANG-1) or ANG-2 with vascular endothelial growth factor (VEGF) improves myocardial perfusion and contractile function by modulating vascular adaptation of neoangiogenic microvessels in a chronic ischemic swine model. Four weeks after occlusion of the left circumflex coronary artery (LCx), animals were injected with AdVEGF(165) (n=6), AdVEGF(165)+AdANG-1 (n=6), AdVEGF(165)+AdANG-2 (n=6) or control vector (n=5) into the left ventricular posterolateral wall. Regional perfusion by fluorescent microspheres and segmental myocardial tissue velocity by tissue Doppler imaging (TDI) were assessed at baseline, 4 weeks post occlusion and 4 weeks post therapy. Despite similar vascular growth following VEGF+ANG-1 and VEGF+ANG-2 treatments, transmural myocardial contractility improved only when VEGF was paired with ANG-1. In contrast, regional systolic function deteriorated uniformly across subepicardial, mid-myocardial and subendocardial segments in VEGF and VEGF+ANG-2 treated groups. Contractile improvement was associated with enhanced vascular stability through augmented arteriole formation, tight structural integration between VE-cadherin and beta-catenin at endothelial junctions and improved cross-talk between endothelium and myocardium. Structural stability of developing intramyocardial microvessels contributes to systolic function during ischemic neovascularization. Coordinated regulation of angiogenic revascularization that supports vascular stability is a key aspect in improving therapeutic outcomes in ischemic myocardium.

The cardiac microvasculature in hypertension, cardiac hypertrophy and diastolic heart failure.

Recent studies revealed an exceedingly high mortality with diastolic heart failure that was previously regarded as relatively benign compared to systolic heart failure. Prominent risk factors for diastolic heart failure are increasing age, hypertension and diabetes. These risk factors are associated with coronary microvascular rarefaction and resultant decreased coronary flow reserve, thereby rendering the myocardium vulnerable to ischemia. We discuss the importance of angiogenic gene programming in preserving the coronary microvasculature, preserving cardiac function and altering disease course. Further, we discuss the possible utility of therapies that activate hypoxia inducible factor-1 in preventing rarefaction of the coronary microvasculature and maintaining cardiac diastolic function.

Coronary reactivity, homocysteine and methylenetetrahydrofolate reductase gene variation in young men during pravastatin therapy.

High plasma homocysteine (Hcy) has been linked to impaired endothelial function. We investigated whether treatment with pravastatin affects the Hcy levels. Moreover, we studied whether the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism affects coronary vasomotion at baseline and during the treatment with pravastatin. Fifty-one healthy, mildly hypercholesterolemic men (mean age 35+/-4 years) attended this randomised, double-blind, placebo-controlled study. The volunteers were randomised into groups with 6-month treatment with pravastatin (40 mg/day, n=25) or placebo (n=26). Coronary blood flow measurements with positron emission tomography at rest and during adenosine infusion as well as biochemical analyses were done at baseline and at the end of the treatment period. The Hcy concentration decreased significantly during the pravastatin therapy (-0.81+/-1.46 micromol/l, p=0.01), but not during placebo (0.02+/-2.39 micromol/l, p=0.97). The MTHFR polymorphism did not affect the Hcy concentration or coronary flow indices. Neither did the MTHFR polymorphism modulate the effects of pravastatin on coronary vasomotion. In conclusion, a 6-month therapy with pravastatin decreases Hcy concentration in Finnish healthy young men. The MTHFR genotype is neither a determinant of baseline coronary flow indices nor does it modulate the effect of pravastatin on coronary reactivity.

Coronary collateralization shows sex and racial-ethnic differences in obstructive artery disease patients.

BACKGROUND: Coronary collateral circulation protects cardiac tissues from myocardial infarction damage and decreases sudden cardiac death. So far, it is unclear how coronary collateralization varies by race-ethnicity groups and by sex. METHODS: We assessed 868 patients with obstructive CAD. Patients were assessed for collateral grades based on Rentrop grading system, as well as other covariates. DNA samples were genotyped using the Affymetrix 6.0 genotyping array. To evaluate genetic contributions to collaterals, we performed admixture mapping using logistic regression with estimated local and global ancestry. RESULTS: Overall, 53% of participants had collaterals. We found difference between sex and racial-ethnic groups. Men had higher rates of collaterals than women (P-value = 0.000175). White Hispanics/Latinos showed overall higher rates of collaterals than African Americans and non-Hispanic Whites (59%, 50% and 48%, respectively, P-value = 0.017), and especially higher rates in grade 1 and grade 3 collateralization than the other two populations (P-value = 0.0257). Admixture mapping showed Native American ancestry was associated with the presence of collaterals at a region on chromosome 17 (chr17:35,243,142-41,251,931, ß = 0.55, P-value = 0.000127). African ancestry also showed association with collaterals at a different region on chromosome 17 (chr17: 32,266,966-34,463,323, ß = 0.38, P-value = 0.00072). CONCLUSIONS: In our study, collateralization showed sex and racial-ethnic differences in obstructive CAD patients. We identified two regions on chromosome 17 that were likely to harbor genetic variations that influenced collateralization.

The influence of hepatic lipase C-480T polymorphism on coronary flow reserve in young men is independent of the plasma cholesterol level.

BACKGROUND: The hepatic lipase (HL) gene C-480T promoter polymorphism affects gene transcription and enzyme activity and leads to CC, CT, and TT genotypes. Recently, HL expression was detected in macrophages. It has been postulated that HL might have a direct role in the pathogenesis of atherosclerosis without changes in the plasma profile. We hypothesized that the difference of plasma cholesterol level may not influence the effect of HL genotype on coronary reactivity. METHODS: A total of 108 young men (aged 34+/-5 years) were genotyped and divided into three groups. These groups contained 45, 49 and 14 men having either normal (4.9+/-1.2 mmol/L), mildly (5.5+/-0.8 mmol/L) or severely (7.8+/-1.9 mmol/L, subjects with familial hypercholesterolemia) elevated mean plasma cholesterol level, respectively. Myocardial blood flow (MBF) was measured at rest and during adenosine or dipyridamole-induced hyperemia with positron emission tomography using [(15)O] H(2)O. RESULTS: The effect of HL genotype on the indices of MBF was parallel within all cholesterol groups and therefore they were combined. In all subjects, basal flow did not differ between the genotypes. However, men with CC genotype had a significantly higher hyperemic blood flow (3.86+/-1.26 mLg(-1)min(-1) versus 3.20+/-1.38 mLg(-1)min(-1), p=0.007), higher coronary flow reserve (CFR, 4.80+/-1.77 versus 3.77+/-1.43, p=0.001) and lower coronary resistance during hyperemia (25.63+/-9.98 mmHg min g mL(-1) versus 35.00+/-23.95 mmHg min g mL(-1), p=0.003) than T allele carriers. In multivariate regression analysis, after adjustment for age, body mass index, serum lipids, blood pressure, adenosine or dipyridamole administration, and study group, HL polymorphism was an independent predictor of blood flow during hyperemia (p=0.016), coronary resistance (p=0.014), and CFR (p=0.005), respectively. CONCLUSIONS: The HL C-480 T polymorphism is associated with CFR, which is an early indicator of atherosclerosis, independently of the level of plasma cholesterol in young men.

Genetic deletion of fas receptors or Fas ligands does not reduce infarct size after acute global ischemia-reperfusion in isolated mouse heart.

Apoptosis has been shown in cardiac cells under divergent physiological and pathological conditions. However, there has been an ongoing debate upon the relative contribution of cardiomyocyte apoptosis to the myocardial infarct size after ischemia-reperfusion (I-R) injury. We tested the hypothesis that blocking the death receptor pathway of apoptosis through genetic deletion of Fas receptors or Fas ligands would reduce myocardial infarct size caused by acute I-R injury. The hearts isolated from Fas receptor or Fas ligand knockout (KO) mice as well as the C57BL/6J wild-type control mice (N = 6-8 per group) were subjected to 20 min of global ischemia and 30 min of reperfusion in Langendorff mode. Our results show that the infarct size, determined with triphenyltetrazolium chloride staining, was not significantly different between the three groups (i.e., 30.2 +/- 3.9% for wild-type controls, 30.0 +/- 2.1% for Fas ligand KOs, and 23.8 +/- 3.6% for Fas receptor KOs; mean +/- SEM, p > 0.05). Postischemic leakage of lactate dehydrogenase, another marker of necrotic cellular injury, also was not significantly different between these groups (p > 0.05). In addition, postischemic ventricular contractile function as well as coronary flow were similar for all the experimental groups (p > 0.05). In conclusion, contrary to our original hypothesis, the present study in the gene KO mice suggests that the Fas ligand- and Fas receptor-mediated death receptor pathway of apoptosis is not the primary determinant of myocardial infarct size and ventricular dysfunction caused by acute global I-R injury in the isolated perfused mouse heart.

Impact of paraoxonase polymorphism (Q192R) on endothelial function in intact coronary circulation.

Paraoxonase-1 (PON1) can protect endothelial function by preventing the oxidation of low-density lipoprotein (LDL) cholesterol and retarding the development of atherosclerosis. We examined whether PON1 polymorphism influences endothelium-dependent coronary vasomotor responses. Sixty-seven patients underwent diagnostic cardiac catheterization, but showed no significant coronary artery stenosis. In all patients, PON1 genotypes (Q/Q, Q/R and R/R) were determined, and provocative testing was performed by the intracoronary administration of graded doses of bradykinin (BK; 0.2, 0.6 and 2.0 mug/min) and acetylcholine (ACh; 3, 10 and 30 mug/min). Coronary blood flow (CBF) was evaluated by a Doppler guide wire. The patients were divided into 2 groups on the basis of ACh testing: one with coronary spastic angina (CSA) and one with non-CSA. The frequencies of the PON1 genotype in the CSA group did not differ significantly from those in the non-CSA group. In the non-CSA group, the patients were subdivided into 2 groups: a group with the Q/Q or Q/R genotypes and a group with the R/R genotype. The vasoconstrictive responses of the epicardial coronary artery to ACh were comparable between the Q/Q + Q/R and R/R groups. Also, the coronary vasodilations induced by BK in the R/R group were similar to those in the QR + QQ group. There were no significant differences in the CBF responses induced by BK or ACh between the Q/Q + Q/R and R/R groups. In conclusion, as estimated by BK and ACh testing, our findings suggest that PON1 genotypes may not play a critical role in the modulation of endothelial vasomotor function in the intact coronary circulation.