A positive family history of premature coronary artery disease is associated with impaired endothelium-dependent coronary blood flow regulation

Mutated CYP17A1 promotes atherosclerosis and early-onset coronary artery disease

BACKGROUND

Coronary artery disease (CAD) is a multi-factor complex trait and is heritable, especially in early-onset families. However, the genetic factors affecting the susceptibility of early-onset CAD are not fully characterized.

METHODS

In the present study, we identified a rare nonsense variant in the CYP17A1 gene from a Chinese Han family with CAD. To validate the effect of this variation on atherosclerosis and early-onset coronary artery disease, we conducted studies on population, cells, and mice.

RESULTS

The mutation precisely congregated with the clinical syndrome in all the affected family members and was absent in unaffected family members and unrelated controls. Similar to the human phenotype, the CYP17A1-deficient mice present the phenotype of metabolic syndrome with hypertension, increased serum glucose concentration, and presentation of central obesity and fatty liver. Furthermore, CYP17A1 knockout mice or CYP17A1 + ApoE double knockout mice developed more atherosclerotic lesions than wild type (WT) with high fat diary. In cell models, CYP17A1 was found to be involved in glucose metabolism by increasing glucose intake and utilization, through activating IGF1/mTOR/HIF1-α signaling way, which was consistent in CYP17A1 knockout mice with impaired glucose tolerance and insulin resistance.

CONCLUSIONS

Through our study of cells, mice and humans, we identified CYP17A1 as a key protein participating in the pathophysiology of the atherosclerotic process and the possible mechanism of CYP17A1 C987X mutation induced atherosclerosis and early-onset CAD involving glucose homeostasis regulation was revealed. Video Abstract.

Frequency and Clinical Impact of Family History of Coronary Artery Disease in Patients with Vasospastic Angina

BACKGROUND

Family history (FH) of coronary artery disease (CAD) [FH-CAD] is a well-known risk factor for atherosclerotic CAD. However, FH-CAD frequency in patients with vasospastic angina (VSA) remains unknown, and the clinical characteristics and prognosis of VSA patients with FH-CAD are unclear. Therefore, this study compared FH-CAD frequency between patients with atherosclerotic CAD and those with VSA and examined the clinical characteristics and prognosis of VSA patients with FH-CAD.

METHODS

Coronary angiography and spasm provocation tests (SPT) were used to investigate chest pain of coronary artery origin in patients classified into atherosclerotic CAD (362 cases), VSA (221 cases; positive for SPT) and non-VSA (73 cases; negative for SPT) groups, with FH-CAD being defined. In the VSA group, flow-mediated vasodilation (FMD) and nitroglycerin-independent vasodilation (NID) via brachial artery echocardiography and clinical symptoms in the groups with and without FH-CAD were checked, with Kaplan-Meier curves revealing major adverse cardiovascular events (cardiac death and rehospitalisation for cardiovascular disease) between the two groups.

RESULTS

The atherosclerotic CAD group had a significantly lower FH-CAD frequency (12%, p = 0.029) than the VSA (19%) and non-VSA groups (19%). FH-CAD was more common in females in the VSA and non-VSA groups than in the atherosclerotic CAD group (p < 0.001). Nonpharmacological treatment for CAD in FH-CAD was more common in the atherosclerotic CAD group (p = 0.017). In the VSA group, FH-CAD tended to be more common in females (p = 0.052). Although no differences in FMD of the brachial artery were observed between the groups, the FH-CAD (+) group had significantly higher NID than the FH-CAD (-) group (p = 0.023). Kaplan-Meier's analysis revealed a similar prognosis between the two groups, and other clinical characteristics did not differ.

CONCLUSION

Patients with VSA have a higher FH-CAD frequency than those with atherosclerotic CAD, especially in females. Although FH-CAD may affect vascular function in patients with VSA, its effect on the severity and prognosis of VSA appears to be minimal. FH-CAD and its confirmation may assist in CAD diagnosis, especially in female patients.

Therapeutic potential of colchicine in cardiovascular medicine: a pharmacological review

Colchicine is an ancient herbal drug derived from Colchicum autumnale. It was first used to treat familial Mediterranean fever and gout. Based on its unique efficacy as an anti-inflammatory agent, colchicine has been used in the therapy of cardiovascular diseases including coronary artery disease, atherosclerosis, recurrent pericarditis, vascular restenosis, heart failure, and myocardial infarction. More recently, colchicine has also shown therapeutic efficacy in alleviating cardiovascular complications of COVID-19. COLCOT and LoDoCo2 are two milestone clinical trials that confirm the curative effect of long-term administration of colchicine in reducing the incidence of cardiovascular events in patients with coronary artery disease. There is growing interest in studying the anti-inflammatory mechanisms of colchicine. The anti-inflammatory action of colchicine is mediated mainly through inhibiting the assembly of microtubules. At the cellular level, colchicine inhibits the following: (1) endothelial cell dysfunction and inflammation; (2) smooth muscle cell proliferation and migration; (3) macrophage chemotaxis, migration, and adhesion; (4) platelet activation. At the molecular level, colchicine reduces proinflammatory cytokine release and inhibits NF-κB signaling and NLRP3 inflammasome activation. In this review, we summarize the current clinical trials with proven curative effect of colchicine in treating cardiovascular diseases. We also systematically discuss the mechanisms of colchicine action in cardiovascular therapeutics. Altogether, colchicine, a bioactive constituent from an ancient medicinal herb, exerts unique anti-inflammatory effects and prominent cardiovascular actions, and will charter a new page in cardiovascular medicine.

Potential Effects of Metformin on the Vitality, Invasion, and Migration of Human Vascular Smooth Muscle Cells via Downregulating lncRNA-ATB

Objective

To elucidate the role of metformin in influencing VSMCs via the involvement of lncRNA-ATB.

Methods

qRT-PCR was conducted to detect serum levels of lncRNA-ATB and p53 in CHD patients (n = 50) and healthy subjects (n = 50). Correlation in serum levels of lncRNA-ATB and p53 in CHD patients was assessed by Pearson correlation test. ROC curves were depicted for analyzing the predictive potential of lncRNA-ATB in the occurrence of CHD. After metformin induction in VSMCs overexpressing lncRNA-ATB, relative levels of lncRNA-ATB and p53 were detected. Meanwhile, proliferative, migratory, and invasive abilities in VSMCs were, respectively, examined by CCK-8 and transwell assay. The interaction between lncRNA-ATB and p53 was tested by RIP. In addition, the coregulation of lncRNA-ATB and p53 in cell functions of VSMCs was finally determined.

Results

Increased serum level of lncRNA-ATB and decreased p53 level were detected in CHD patients than those of healthy subjects. LncRNA-ATB could interact with p53 and negatively regulate its level. In addition, lncRNA-ATB could serve as a potential biomarker for predicting the occurrence of CHD. The overexpression of lncRNA-ATB triggered viability, migratory, and invasive abilities in VSMCs, and the above trends were abolished by metformin induction. The overexpression of p53 partially abolished the promotive effects of lncRNA-ATB on proliferative, migratory, and invasive abilities in VSMCs.

Conclusions

Metformin induction inhibits proliferative, migratory, and invasive abilities in VSMCs by downregulating lncRNA-ATB, which may be related to p53 activation.

Correlation between plasma homocysteine and first myocardial infarction in young patients: Case-control study in Constanta County, Romania

An elevated level of total plasma homocysteine has been associated with a higher risk of atherosclerosis and coronary heart disease. The aim of our research was to study the relation between homocysteine and myocardial infarction (MI) in young patients. We conducted a case-control study in Constanţa County, Romania including 61 patients, divided in two groups. The first group, the MI group, consisted of 28 patients, male (67.9%) and female (32.1%) aged less than 45 years who were consecutively admitted to the Intensive Coronary Care Unit of the Emergency County Hospital of Constanţa from September 1, 2017 to August 31, 2018 (12 months), with an established diagnosis of first acute MI. The second group, the control group, included 33 patients, male (75.8%) and female (24.2%) aged less than 45 years, with cardiovascular risk factors and/or stable angina pectoris that were consecutively addressed for ambulatory cardiac evaluation at the Outpatient Clinic of Emergency County Hospital of Constanţa during the same period. Fasting plasma homocysteine was determined in both groups, within 24 h after MI onset, respectively after first cardiac exam in the controls. High homocysteine was statistically confirmed to be a risk factor in the study group, especially in association with smoking, chronic kidney disease (CKD), and to a lesser extent with diabetes mellitus (DM) and hypertension. Data analysis was performed using IBM SPSS Statistics 23. The procedures used included descriptive statistics, parametric statistical tests (Independent sample t-test), non-parametric statistical tests [Chi-square test of the association, with the evaluation of odds ratio (OR)]; the significance level used in the analysis (P-value) was 0.05. After adjusting for variables, our study results pointed out a strong association between plasma homocysteine and first acute MI among young patients, emphasising plasma homocysteine as a possible risk factor for myocardial infarction.

Positive family history of cardiovascular disease and long-term outcomes after coronary artery bypass grafting: a genetic paradox?

OBJECTIVES

Parental cardiovascular disease (CVD) is a known risk factor for premature CVD. It is unknown whether a positive family history (PFH) affects outcomes after coronary artery bypass grafting (CABG).

METHODS

Data come from a retrospective longitudinal study of CABG patients consecutively recruited from 2001 to 2018 (n = 5389). From this study, 2535 patients with premature CVD undergoing CABG under the age of 60 years and information on parental CVD were identified. The Framingham offspring study criteria were used to identify PFH of CVD. Multivariable Cox proportional hazards regression models were used to assess the effect of PFH on overall and major adverse cardiovascular and cerebrovascular event-free survival.

RESULTS

A total of 273 deaths and 428 major adverse cardiovascular and cerebrovascular events occurred during follow-up. PFH of CVD was found in 54.2% of patients (n = 1375). Within these patients, 66.1% had a father who experienced a premature cardiovascular event (n = 909), 27.8% a mother (n = 382) and 6.1% both a mother and a father (n = 84). In the majority of cases, the patient's parent had experienced a cardiac event (85.9%, n = 1181) and 14.1% of patients with PFH reported parental stroke (n = 194). Following CABG, PFH was associated with improved overall [adjusted hazards ratio (HR) 0.67, 95% confidence interval (CI) 0.50-0.90; P = 0.008] and major adverse cardiovascular and cerebrovascular event-free survival (adjusted HR 0.73, 95% CI 0.68-0.89; P = 0.01). Among the covariates adjusted for age, diabetes, renal insufficiency, peripheral arterial disease, ejection fraction, previous cerebrovascular events and previous mediastinal radiation were all associated with poorer outcomes.

CONCLUSIONS

Although it is well established that a PFH increases the risk of requiring CABG at younger ages, this study shows that, paradoxically, PFH is also protective regarding long-term outcomes.

REGISTRATION NUMBER LOCAL IRB

UN4232 297/4.3 (retrospective study).

TGFβ, smooth muscle cells and coronary artery disease: a review

Excessive vascular smooth muscle cell (SMC) proliferation, migration and extracellular matrix (ECM) synthesis are key events in the development of intimal hyperplasia, a pathophysiological response to acute or chronic sources of vascular damage that can lead to occlusive narrowing of the vessel lumen. Atherosclerosis, the primary cause of coronary artery disease, is characterised by chronic vascular inflammation and dyslipidemia, while revascularisation surgeries such as coronary stenting and bypass grafting represent acute forms of vascular injury. Gene knockouts of transforming growth factor-beta (TGFβ), its receptors and downstream signalling proteins have demonstrated the importance of this pleiotropic cytokine during vasculogenesis and in the maintenance of vascular homeostasis. Dysregulated TGFβ signalling is a hallmark of many vascular diseases, and has been associated with the induction of pathological vascular cell phenotypes, fibrosis and ECM remodelling. Here we present an overview of TGFβ signalling in SMCs, highlighting the ways in which this multifaceted cytokine regulates SMC behaviour and phenotype in cardiovascular diseases driven by intimal hyperplasia.

Retinal vascular function in asymptomatic individuals with a positive family history of cardiovascular disease

PURPOSE

To compare retinal microvascular function in healthy individuals with and without a positive family history (FH) of cardiovascular disease (CVD).

METHODS

Retinal vessel reactivity was assessed by means of dynamic retinal vessel analysis in 38 healthy subjects aged between 30 and 66 years with a positive FH of CVD and 37 age- and gender-matched control subjects. Other assessments included blood pressure (BP) profiles, blood glucose and lipid metabolism markers, Framingham risk scores (FRS), carotid intima-media thickness (c-IMT) and brachial flow-mediated dilation (FMD).

RESULTS

Family history-positive subjects showed decreased retinal arterial baseline diameter fluctuation, dilation amplitude, percent dilation, and overall constriction response slope (p = 0.001; p = 0.015; p = 0.001; and p < 0.001, respectively) and increased percent constriction (p = 0.008). On the venous side, baseline-corrected flicker response and dilation response slope were decreased in the FH-positive group (p = 0.009 and p = 0.010, respectively). There were no significant differences between groups in c-IMT scores or FMD parameters (all p > 0.05). The arterial MC% correlated negatively with decreased high-density lipoprotein cholesterol (r = -0.52, p = 0.002) in only FH-positive group.

CONCLUSION

Although macrovascular function is preserved in individuals with FH positive for CVD but with low FRS, there are, however, functional impairments at the retinal microvascular level that correlate with established plasma markers for cardiovascular risk.

Enhanced status of inflammation and endothelial activation in subjects with familial hypercholesterolaemia and their related unaffected family members: a case control study

Background

Familial hypercholesterolaemia (FH) leads to premature coronary artery diseases (CAD) which pathophysiologically can be measured by inflammation, endothelial activation and oxidative stress status. However, the status of these biomarkers among related unaffected relatives of FH cases and whether FH is an independent predictor of these biomarkers have not been well established. Thus, this study aims to (1) compare the biomarkers of inflammation, endothelial activation and oxidative stress between patients with FH, their related unaffected relatives (RUC) and normolipaemic subjects (NC) (2)determine whether FH is an independent predictor of these biomarkers.

Methods

One hundred thirty-one FH patients, 68 RUC and 214 matched NC were recruited. Fasting lipid profile, biomarkers of inflammation (hsCRP), endothelial activation (sICAM-1 and E-selectin) and oxidative stress [oxidized LDL (oxLDL), malondialdehyde (MDA) and F2-isoprostanes (ISP)] were analyzed and independent predictor was determined using binary logistic regression analysis.

Results

hsCRP was higher in FH and RUC compared to NC (mean ± SD = 1.53 ± 1.24 mg/L and mean ± SD = 2.54 ± 2.30 vs 1.10 ± 0.89 mg/L, p < 0.05). sICAM-1 and E-selectin were higher in FH compared to NC (mean ± SD = 947 ± 742 vs 655 ± 191 ng/mL, p < 0.001 and 175 ± 131 vs 21.6 ± 10.7 ng/mL, p < 0.001 respectively) while sICAM-1 concentration was higher in RUC compared to NC (mean ± SD = 945 ± 379 vs 655 ± 191 ng/mL, p < 0.01). Biomarkers of oxidation (ox-LDL, MDA and ISP) were elevated in FH compared to NC [mean ± SD = (48.2 ± 26.8 vs 27.3 ± 13.2 mU/L, p < 0.001), (2.57 ± 1.3 vs 1.20 ± 0.30 nmol/mL, p < 0.001) and (645 ± 396 vs 398 ± 20.5 pg/L, p < 0.001) respectively], but no significant differences were observed between RUC and NC (p > 0.05). FH was an independent predictor for sICAM-1 (p = 0.007), ox-LDL (p < 0.001) and MDA (p < 0.001) while RUC independently predicted for sICAM-1 (p < 0.001).

Conclusion

The screening for FH is vital as all biomarkers associated with atherogenesis are higher in these subjects and FH also independently predict biomarkers of endothelial activation and oxidative stress. Furthermore, despite not fulfilling the diagnostic criteria for FH, related unaffected family members that may not phenotypically express the mutation may still be at risk of developing CAD as reflected from the enhanced inflammatory and endothelial activation status observed in this group. This highlights the need to not only conduct family tracing in indexed FH cases, but also assess the coronary risk among family members that do not fulfil the FH diagnostic criteria.

Current Understanding of Atherogenesis

Scientific understanding of atherogenesis is constantly developing. From Virchow's observations 160 years ago we now recognize the endothelial response to injury as inflammatory, involved in all stages of atherosclerosis. Endothelial activation may cause reversible injury or dysfunction, or lead to irreparable damage. Indeed, early atherosclerosis is reversible. The introduction of genome-wide association testing has furthered the identification of potentially important genetic variants that help explain the heritability of coronary artery disease as well as spontaneous cases of severe coronary artery disease in patients with otherwise minimal risk factors. However, the mechanisms by which many of the newer variants exert their influence remain unknown.

Endothelial Dysfunction Markers in Low Cardiovascular Risk Individuals: Comparison of Males and Females

BACKGROUND

Cardiovascular diseases (CVD) account for approximately 50% of the total deaths in Turkey. Most of them are related with atherosclerotic coronary heart disease. Predictive value of endothelial dysfunction markers related with the earliest stage of atherosclerosis has been getting more attention. We hypothesized that differences in endothelial dysfunction biochemical markers among genders would aid to capture proatherogenic activity that was not diagnosed by conventional risk assessment scoring systems.

METHODS

We assessed the endothelial dysfuntion markers in 92 Turkish adults who were in the »low CV risk group« according to ESC (European Society of Cardiology)-Score Risk Charts. We compared the males and females.

RESULTS

We observed higher endothelial dysfunction rates in males, with higher median and mean levels of e-NOS, ox-LDL before and after adjustment for HDL lowness and obesity (P=0.018, P=0.036 for NOS; P=0.000, P=0.004 for ox-LDL, respectively). Men had higher hs-CRP levels than females before adjustment (P=0.021). Decreased e-NOS levels were related with FMD for females before adjustment for confounders (P=0.028). We also found significant correlation between e-NOS and ox-LDL levels both before (r=0.360, P<0.001) and after adjustment (r=0.366, P<0.01) for confounders which pointed out the nitrosative stress. In multivariate regression analyses, after adjusting for other endothelial dysfunction markers which were not included in the ESC-risk scoring system, decreased e-NOS levels were independently asssociated with impaired flow mediated dilatation for females (odds ratio 0.3; P=0.038).

CONCLUSIONS

Our results underline the importance of gender in evaluating endothelial dysfunction biochemical markers to assess cardiovascular risk for low CV risk indivuals.

Effect of long-term Vitamin C intake on vascular endothelial function in diabetic children and adolescents: A pilot study

Background:

This study attempted to determine the effects of long-term use of Vitamin C on vascular endothelial function.

Materials and Methods:

During a pilot clinical trial study conducted at Imam Hussein Hospital (Isfahan) in 2014–2015, a total of forty diabetic patients were selected and then assigned randomly into two twenty-subject groups receiving Vitamin C and placebo tablets. The patients were treated with Vitamin C or placebo for 6 months. All patients were examined through echocardiography in terms of cardiac function before and after treatment. To evaluate the endothelial function (flow-mediated dilatation [FMD], intima-media thickness), they underwent arterial Doppler. Moreover, the chemical indices of vascular function were tested through intercellular adhesion molecule and vascular cell adhesion molecule (VCAM). Finally, the results were compared between the two groups.

Results:

Based on the results, the mean left ventricular mass significantly reduced after the intervention in the group treated with Vitamin C (from 76.35 ± 25.6–68.62 ± 22.66; P = 0.015) while there was no significant difference observed in the control group (from 67.58 ± 25.38–71.63 ± 26.84; P = 0.19) but no statistically difference between the two groups-based repeated measures ANOVA test (P = 0.6). In addition, the mean of VCAM changes was significantly difference between the two groups (P < 0.001).

Conclusion:

Long-term use of Vitamin C in diabetic patients can improve certain echocardiographic parameters such as ejection fraction, fractional shortening, and FMD, which in turn enhances vascular endothelial function.

Positive effects of aggressive vasodilator treatment of well-treated essential hypertensive patients

Increased systemic vascular resistance and coronary microvascular dysfunction are well-documented in essential hypertension (EH). We investigated the effect of additional vasodilating treatment on coronary and peripheral resistance circulation in EH patients with high systemic vascular resistance index (SVRI) despite well-treated blood pressure (BP). We enroled patients on stable antihypertensive treatment that were given intensified vasodilating therapy (ACE inhibitor, angiotensin II receptor blocker or calcium channel blocker). Before and following 6 months of intensified therapy, coronary resting and maximal artery flow were measured by transthoracic Doppler echocardiography to calculate coronary flow reserve (CFR) and minimum vascular resistance (C-R_min). Cardiac output was estimated by inert gas rebreathing to calculate SVRI. Maximal forearm blood flow was determined by venous occlusion plethysmography to calculate minimum vascular resistance (F-R_min). Patients were assigned into two groups: high-SVRI and low-SVRI subgroups, based on a median split at baseline. Following additional treatment SVRI decreased more in the high-SVRI group than in the low-SVRI group (14.4 vs -2.2%: P=0.003), despite similar baseline ambulatory BP (132/81 mm Hg) and BP reduction (6.5 and 4.6%: P=0.19). F-R_min remained unchanged (6.5 vs -2.0%: P=0.30), while C-R_min decreased by 22 and 24% (P=0.80) and CFR increased by 23 and 17% (P=0.16). Thus, intensified vasodilating therapy improved SVRI more in patients with high SVRI than in those with low SVRI. Regardless of SVRI status, the treatment improved cardiac but not forearm dilatation capacity. The substantial improvement of the hypertensive cardiac microvascular dysfunction was not related to the reduction in SVRI.

Endothelial dysfunction and coronary artery disease: a state of the art review

Atherosclerotic coronary artery disease (CAD) is a major cause of morbidity and mortality in the developed world. Endothelial dysfunction plays an important role in the development of atherosclerosis and predicts cardiovascular (CV) outcomes independent of conventional CV risk factors. In recent years, there have been tremendous improvements in the pharmacological prevention and management of CAD. In this review, the pathophysiology of endothelial dysfunction in relation to CAD is discussed and various techniques of invasive and noninvasive assessments of peripheral and coronary endothelial function described. In addition, evidence for the association of endothelial dysfunction and CV outcomes has been examined and finally the role of therapeutic interventions in endothelial dysfunction has been discussed.

Reversal of hyperglycemia: effects on nitric oxide signaling

BACKGROUND

Hyperglycemia in patients with acute coronary syndromes is associated with poor outcomes, and its rapid correction with insulin infusion has been shown to restore platelet responsiveness to nitric oxide and to suppress superoxide (O2(-)) generation. Thioredoxin-interacting protein has emerged recently as a pivotal modulator of hyperglycemia-induced inflammation, O2(-) production, and impairment of nitric oxide signaling, but it is not known whether its expression in platelets can be downregulated rapidly.

METHODS

In 12 hyperglycemic patients with acute coronary syndrome, we evaluated the putative role of thioredoxin-interacting protein suppression in the platelet nitric oxide response after reversal of hyperglycemia with insulin infusion.

RESULTS

Insulin infusion for 13.0 ± 0.8 (standard error of the mean) hours decreased blood glucose level from 16.6 ± 1.6 mmol/L to 8.7 ± 1.4 mmol/L (P = .002). This induced (1) sensitization of antiaggregatory response to nitric oxide (from 6.5% ± 7.7% to 39.7% ± 7.0%, P < .0001); (2) improved endothelial progenitor cell function (from a median of 45 to 180 colony-forming units, P < .05); and (3) decreases of whole blood reactive oxygen species content (P < .05). However, there was no significant suppression of platelet thioredoxin-interacting protein expression (mean decrease, 59 arbitrary units; 95% confidence interval, -193 to +74).

CONCLUSIONS

Correction of hyperglycemia in patients with acute coronary syndrome rapidly reverses oxidative stress, restoring both platelet nitric oxide responsiveness and endothelial progenitor cell function, but this process is largely or entirely independent of thioredoxin-interacting protein.

Association of LOXIN, a new functional splicing isoform of the OLR1 gene, with severity and prognostic localization of critical coronary artery stenoses

AIMS

To evaluate the association between LOXIN, a new functional protective splicing isoform of the oxidized LDL receptor 1 (OLR1) gene, and the severity of coronary artery stenoses.

METHODS

We analyzed 100 consecutive patients with coronary artery disease (CAD) and 100 controls, all evaluated by a new molecular biology test using highly specific allele primers able to identify the single nucleotide variation (IVS4-14 A>G) in the OLR1 gene (Loxin Test - Technogenetics). All the patients and the controls underwent coronary angiography and, for quantitative evaluation, we used both vessel and stenosis score, and SYNTAX score to evaluate the severity of CAD. Moreover, we defined the prognostic localization of CAD as a critical stenosis (>50%) of the left main and/or proximal segment of left anterior descending artery (LAD). Finally, we evaluated a correlation with the presence of diabetes mellitus, dyslipidemia, hypertension, smoking and family history of CAD.

RESULTS

In this selected population, even though the 'AA nonrisk haplotype' is more frequent in the controls, we did not find any statistically significant correlation between the severity of CAD or the prognostic localization of critical stenosis and the difference of IVS4-14 A>G OLR1 genotype (P > 0.05). CAD patients showed significantly higher frequencies of dyslipidemia and smoking (P < 0.05) than controls, but no significant association was found between overall risk factors and the OLR1 polymorphism.

CONCLUSION

In this selected population, we did not find any correlation of LOXIN with the severity or prognostic localization of CAD on left main and/or proximal LAD.

Pathophysiology of coronary vascular remodeling: relationship with traditional risk factors for coronary artery disease

The relationship between cardiovascular risk factors and vascular remodeling is a relatively new area of investigation. We discuss the various mechanisms by which cardiovascular risk factors cause vascular remodeling. Endothelial dysfunction, lipoprotein alterations, inflammation, and platelet activation are the mechanisms by which remodeling occurs. Plaque composition also plays an important role in directing remodeling. Plaque with extensive calcification is more likely to undergo constrictive remodeling. Positive and negative remodeling is based on how these factors coordinate and determine the direction of remodeling. Matrix metalloproteinases perform a crucial role in vascular remodeling. Advanced glycation end-products are key substances involved in the negative remodeling associated with diabetes. Remodeling in hypertension can be either eutrophic or hypertrophic. Endothelial dysfunction and low-grade inflammation lead to negative remodeling in hypertension. Dyslipidemia can be associated with either positive or negative remodeling. High high-density lipoprotein is associated with positive remodeling and high low-density lipoprotein with negative remodeling. Smoking causes endothelial dysfunction, increased oxidative stress, and decreased nitric oxide synthesis leading to inward remodeling. Aging also causes endothelial dysfunction and predisposes to negative remodeling. Knowledge of these associations can elucidate various clinical presentations and guide therapeutic choices in the future.

A potent anti-thrombosis peptide (vasotab TY) from horsefly salivary glands

Vasotab TY is a KGD (Lys-Gly-Asp)-containing peptide identified from salivary glands of the horsefly of Tabanus yao. We have previously reported that vasotab TY showed a strong vasodilator activity. In the present study, vasotab TY was found to inhibit platelet aggregation effectively. It completely inhibited platelet aggregation induced by adenosine diphosphate (ADP) at the concentration of 9.6μg/ml. Vasotab TY significantly reduced thrombus weight in rat arteriovenous shunt model and inhibited thrombosis in carrageenan-induced mouse tail thrombosis model in vivo. Vasotab TY competitively bound to glycoprotein IIb/IIIa (GPIIb/IIIa) with eptifibatide, a well-known KGD-containing cyclic heptapeptide containing high specificity and high affinity for GPIIb/IIIa, suggesting that it is an antagonist of the fibrinogen receptor GPIIb/IIIa on the surface of platelet. The KGD motif in vasotab TY may facilitate the binding of it to GPIIb/IIIa. Vasotab TY showed a half-life of more than 1h in vivo. It showed little side effects including little bleeding, no hemolytic activity on human blood red cells and no cytotoxicity on human keratinocyte and THP-1 cells. Combined its vasodilator and platelet inhibitory functions, vasotab TY might be an excellent candidate for the development of clinical anti-thrombosis medicines.

Hydrogen peroxide mediates endothelium-dependent dilation of coronary arterioles in obese rats on a low-carbohydrate diet

OBJECTIVE

Endothelium-dependent vasodilation of coronary arterioles is impaired in obese rats and may be improved by a LCD. The aim of this study is to elucidate the mechanism by which this improvement occurs.

METHODS

We used four groups of male Zucker rats: lean and obese on either SD or LCD. Coronary arterioles were cannulated and pressurized for diameter measurements during administration of acetylcholine or sodium nitroprusside or during flow. Real-time PCR was performed to quantify mRNA expression of CuZnSOD and catalase.

RESULTS

The LCD significantly increased endothelium-dependent dilation in the obese rats. l-NAME and indomethacin reduced responses to flow and acetylcholine in the lean rats without any effect on the obese on either diet. In contrast, TEA and catalase blocked flow-dependent and acetylcholine-induced dilation in the obese on either diet, while no effect was observed on the lean. The LCD in the obese significantly up-regulated catalase mRNA expression and slightly increased CuZnSOD mRNA levels.

CONCLUSIONS

A LCD improves endothelium-dependent vasodilation of coronary arterioles in obese rats through the production of H2 O2 which acts as a hyperpolarizing factor, independent of nitric oxide and PGI2 .

Should your family history of coronary heart disease scare you?

Traditional risk factors explain most of the risk associated with coronary heart disease, and after adjustment for risk factors family history was believed to contribute very little to population-attributable risk of coronary heart disease. However, the INTERHEART study demonstrated an independent association of family history of coronary heart disease with acute myocardial infarction. To assess this relationship more comprehensively in multiple datasets in different populations, we carried out a detailed review of the available evidence. Case-control studies involving 17,202 cases and 30,088 controls yielded a pooled unadjusted odds ratio (random-effects model, overall I(2) = 64.6%, P = 0.000) of 2.03 (95% confidence interval: 1.79-2.30), whereas cohort studies that included 313,837 individuals yielded an unadjusted relative risk for future coronary heart disease (random-effects model, overall I(2) = 88.7%, P = 0.000) of 1.60 (95% confidence interval: 1.44-1.77). Although the presence of family history of coronary heart disease indicates a cumulative exposure of shared genes and environment, the risk estimates for family history did not attenuate significantly after adjustment for conventional coronary heart disease risk factors in several studies. It is probably an oversimplification to dichotomize the family history variable into a simple "yes" or "no" risk factor, as the significance of family history is influenced by several variables, such as age, sex, number of relatives, and age at onset of disease in the relatives. Moreover, a quantitative risk-assessment model for the family history variable, such as the "family risk score," has a positive linear relationship with coronary heart disease. More studies are warranted to assess the benefits and risks of intensive interventions, both targeted individually and at the family level, among individuals with a valid family history and borderline elevated risk factors.

Neurological complications post-liver transplantation: impact of nutritional status

Nutritional status is significantly altered in patients with end-stage liver disease (cirrhosis). Malnutrition is a common complication of cirrhosis and is known to be associated with a greater risk of post-operative complications and mortality, especially following liver transplantation. Neurological complications occur frequently after transplant and the nature and extent of these complications may relate to nutritional deficits such as protein-calorie malnutrition as well as vitamin and micronutrient deficiencies. A consensus document from the International Society on Hepatic Encephalopathy and Nitrogen metabolism (ISHEN) has been established in order to address these concerns. Careful assessment of nutritional status followed by prompt treatment of nutritional deficits has the potential to impact on transplant outcome and, in particular, on post-transplant neurological disorders in patients with cirrhosis.

GSTM1, GSTT1, GSTP1, and GSTA1 genetic variants are not associated with coronary artery disease in Taiwan

BACKGROUND AND OBJECTIVE

The genetic variants of xenobiotic-metabolizing enzymes, such as those encoded by glutathione-S-transferase (GST) genes, may be associated with the risk of coronary artery disease (CAD). To investigate the genetic factors for CAD, we examined the GSTM1, GSTT1, GSTP1, and GSTA1 genotypes in a CAD cohort in Taiwan.

METHODS

Our study included 458 CAD participants and 209 control participants who received coronary angiography to assess CAD. The severity of CAD was defined as the number of coronary vessels with 50% or greater stenosis. Sequence variation of the GSTM1 and GSTT1 genes was determined using a polymerase chain reaction (PCR). The GSTP1 (Ile105Val), and GSTA1 (-69C>T) genetic variants were identified using a combination of PCR and restriction fragment length polymorphism analysis. Logistic regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals.

RESULTS

Among the GST genetic variants examined, the GSTT1 null genotype was more prevalent in CAD participants with 3 stenosed vessels than in control participants (OR=1.64, P=.02). This association was no longer observed after adjusting for age, sex, smoking, alcohol use, diabetes mellitus, and serum levels of total cholesterol and high-density lipoprotein cholesterol (OR=1.28, P=.40). Both univariate and multivariate logistic regression analyses found no significant associations between CAD and the other genetic variants, either separately or in combination. In addition, no effects of interactions between the genotypes and environmental factors, such as cigarette smoking, were significantly associated with the risk of CAD.

CONCLUSION

The GST genetic variants examined were not associated with susceptibility to CAD in our Taiwanese cohort. This null association requires further confirmation with larger samples.

Cardiometabolic risk profile of rural South Indians undergoing coronary interventions

BACKGROUND

According to projected estimates, India will bear 60% of the world's cardiovascular disease (CVD) burden by the year 2020. CVD mortality rates are high in South India compared with the rest of India.

OBJECTIVE

The objective of this study was to examine the prevalence of behavioural, biological and metabolic risk factors in different age groups of rural South Indians undergoing coronary interventions under a governmental health insurance scheme.

METHODS

This study includes 1294 patients who underwent coronary interventions. Age, gender and anthropometric measurements were recorded. History of hypertension, diabetes, smoking and family history of ischaemic heart disease was obtained from every subject. Physical activity was assessed using a General Practise physical activity questionnaire. Investigations like haemogram, blood urea, serum creatinine, fasting and postprandial blood glucose, lipid profile and echocardiography were carried out for all patients.

RESULTS

Hypertension was found in 65% patients, 32.38% had diabetes mellitus, 41.65% were smokers (current and former), 37.17% had dyslipidemia, 31.06% had body mass index more than 25 kg/m, 27.04% were physically active, 37% had left ventricular dysfunction, and 8.57% had renal impairment ( table 1). Statistically significant differences were seen in the prevalence rates of different risk factors in the compared age groups (p=<0.05) except for hypertension and dyslipidemia (p=0.596 and 0.306).

CONCLUSIONS

Risks to health, as an area of study, has recently begun to receive attention in developing countries including India. Population-based strategies aimed at bringing down risk factor levels in the community can translate into major public health benefits.

Role of inflammation and endothelial dysfunction in the pathogenesis of cardiac syndrome X

Chest pain with normal coronary arteriograms represents a major diagnostic and therapeutic challenge to contemporary cardiology. Cardiac syndrome X (CSX), defined as typical angina-like chest pain, a positive response to exercise stress testing and normal coronary arteriograms, encompasses patients with a variety of pathogenic mechanisms. Cardiac ischemia has been documented in approximately 25% of CSX patients and is associated with endothelial dysfunction and microvascular vasodilator abnormalities. Increased endothelin-1, a powerful vasoconstrictor, has been suggested to play a pathogenic role. There is a high prevalence of postmenopausal women with CSX and thus estrogen deficiency has also been proposed to represent a possible pathogenic mechanism. Inflammatory mechanisms and endothelial dysfunction at the coronary microvascular level appear to be important in the pathogenesis of CSX. Treatment with agents that have protective effects on the vasculature and also anti-inflammatory properties, such as statins and angiotensin-converting enzyme inhibitors have been effective in improving both symptoms and electrocardiographic signs of myocardial ischemia in patients with CSX. This review discusses the roles for endothelial dysfunction and inflammation in the pathogenesis of CSX, as well as the potential therapeutic implications of these mechanisms.

Pathophysiology of coronary thrombus formation and adverse consequences of thrombus during PCI

Atherosclerosis is a systemic vascular pathology that is preceded by endothelial dysfunction. Vascular inflammation "fuels" atherosclerosis and creates the milieu for episodes of intravascular thromboses. Thrombotic events in the coronary vasculature may lead to asymptomatic progression of atherosclerosis or could manifest as acute coronary syndromes or even sudden cardiac death. Thrombus encountered in the setting of acute coronary syndromes has been correlated with acute complications during percutaneous coronary interventions such as no-reflow, acute coronary occlusion and long term complications such as stent thrombus. This article reviews the pathophysiology of coronary thrombogenesis and explores the complications associated with thrombus during coronary interventions.

High prevalence of a pathological response to acetylcholine testing in patients with stable angina pectoris and unobstructed coronary arteries. The ACOVA Study (Abnormal COronary VAsomotion in patients with stable angina and unobstructed coronary arteries)

OBJECTIVES

This study aimed at determining the prevalence of epicardial and microvascular coronary spasm in patients with anginal symptoms, despite angiographically normal coronary arteries.

BACKGROUND

Despite a typical clinical presentation with exercise-related anginal symptoms (chest pain or dyspnea) with or without occasional attacks of resting chest pain suggestive of coronary artery disease, 40% of patients undergoing diagnostic angiography have normal or "near" normal coronary arteriograms. Many of these patients are given a diagnosis of noncardiac chest pain, and some are considered to have microvascular angina. However, we speculate that abnormal coronary vasomotion (reduced vasodilatation with exercise = reduced coronary flow reserve and/or vasospasm at rest) might also represent a plausible explanation for the symptoms of the patient.

METHODS

This was a prospective study in 304 consecutive patients (50% men, mean age 66 ± 10 years) with exertional anginal symptoms undergoing diagnostic angiography. A total of 139 patients (46%) had ≥50% coronary artery disease in at least 1 coronary artery, 21 patients (7%) had luminal narrowings ranging from >20% to 49%, and 144 patients (47%) had normal coronary arteries or only minimal irregularities (<20% diameter reduction).

RESULTS

One hundred twenty-four patients of the latter (86%) underwent intracoronary acetylcholine (ACH) testing, which elicited coronary spasm in 77 patients (62%), 35 patients (45%) with epicardial spasm (≥75% diameter reduction with reproduction of the symptoms of the patient) and 42 patients (55%) with microvascular spasm (reproduction of symptoms, ischemic electrocardiographic changes, and no epicardial spasm).

CONCLUSIONS

Nearly 50% of patients undergoing diagnostic angiography for assessment of stable angina had angiographically normal or near normal coronary arteriograms. The ACH test triggered epicardial or microvascular coronary spasm in nearly two-thirds of these patients. Our results suggest that abnormal coronary vasomotion plays a pathogenic role in this setting and that the ACH test might be useful to identify patients with cardiac symptoms, despite normal coronaries. (Abnormal Coronary Vasomotion in Patients With Suspected CAD But Normal Coronary Arteries; NCT00921856).

Measurement of heritability of myocardial blood flow by positron emission tomography: the Twins Heart Study

OBJECTIVE

To estimate the heritability of myocardial blood flow (MBF) and coronary flow reserve (CFR) measured with positron emission tomography (PET).

DESIGN

Cross-sectional twin study.

SETTING

General clinical research centre of a university hospital at Atlanta, USA.

PATIENTS

A sample of 180 middle-aged (mean±SD 55±2.9 years) male twins, including 107 monozygotic and 73 dizygotic twins.

MAIN OUTCOME MEASURES

All twins underwent imaging of MBF with PET (13)NH(3) at rest and after adenosine stress during a single imaging session. Structural equation modelling was used to estimate the heritability of MBF at rest and during adenosine stress, as well as of CFR.

RESULTS

The basal MBF (mean±SD) was 0.69±0.20 ml/min/g, and the MBF during adenosine stress was 1.70±0.49 ml/min/g; the CFR was 2.62±0.99. There was substantial heritability for MBF both at rest (0.48, 95% CI 0.29 to 0.64) and during adenosine stress (0.51, 95% CI 0.29 to 0.68), as well as CFR (0.48, 95% CI 0.26 to 0.65).

CONCLUSIONS

For the first time, a substantial genetic contribution to the interindividual variation in MBF and CFR measured with PET in middle-aged men has been demonstrated. The data suggest that a fruitful direction for future work would be the identification of genetic variants for early atherosclerotic stages assessed by PET imaging.

Silent myocardial ischaemia and long-term coronary artery disease outcomes in apparently healthy people from families with early-onset ischaemic heart disease

AIMS

A family history of premature coronary artery disease (CAD) in an apparently healthy individual conveys an increased risk of future CAD. The extent to which inducible myocardial ischaemia exists and is associated with long-term incident CAD in apparently healthy siblings of early-onset CAD patients is unknown.

METHODS AND RESULTS

Asymptomatic siblings (n = 1287, aged 30-59 years) of patients with onset of CAD <60 years of age underwent risk factor screening and maximal graded treadmill testing with nuclear perfusion imaging, and were followed for incident CAD events for up to 25 years. Incident CAD occurred in 15.2% of siblings (68% acute coronary syndromes); mean time to first CAD event was 8.2 ± 5.2 years. Inducible ischaemia was highly prevalent in male siblings (26.9%), and was independently associated with incident CAD. Male siblings ≥ 40 years of age who were low or intermediate risk by traditional risk assessment, had a prevalence of inducible ischaemia and a 10-year risk of incident CAD that were near or ≥ 20%. In female siblings ≥ 40 years of age, the presence of inducible ischaemia was also independently associated with incident CAD, but the prevalence of inducible ischaemia was markedly lower, as was the risk of incident CAD.

CONCLUSION

Inducible ischaemia is highly prevalent in male siblings, suggesting a previously unknown long quiescent period before the occurrence of a clinical event. While inducible ischaemia is associated with a worse prognosis, male siblings with negative tests still bear a high risk of incident disease, such that we propose that in male siblings over 40 years of age, aggressive primary prevention interventions be instituted without nuclear testing. For women, the prevalence of ischaemia was so low as to not warrant screening, but the incidence of CAD was high enough to at least warrant lifestyle interventions.

The prevalence of endothelial dysfunction in patients with and without coronary artery disease

BACKGROUND

Endothelial dysfunction (ED) is frequently present in patients presenting with acute or stable coronary artery disease (CAD), but it is also found in patients presenting with chest pain without angiographic coronary lesions.

HYPOTHESIS

We hypothesized that even in patients without CAD, the presence of cardiovascular (CV) risk factors will correlate with the presence of ED.

METHODS

Our study included a total of 341 consecutive patients referred for coronary angiography. We used pulse wave analysis with a finger plethysmograph (peripheral arterial tonometry) to determine endothelial function. Hyperemia ratio was calculated as the ratio of the postischemic hyperemia response relative to baseline measurement.

RESULTS

The hyperemia ratio was significantly higher in patients without CAD (2.02 ± 0.52) compared with patients with chronic CAD (1.81 ± 0.44, P = 0.001) or acute CAD (1.74 ± 0.49, P < 0.001). Prevalence of ED was 33%, 46%, and 58%, respectively. In multivariate analysis, the presence of CAD, diabetes, and cigarette smoking, and the total number of CV risk factors, were strong predictors of ED. In 67% of the patients without CAD but with ≥3 CV risk factors, ED was present.

CONCLUSIONS

Prevalence of ED in patients with chest pain depends on the presence of CAD and CV risk factors. Patients without CAD but with ≥3 risk factors frequently presented with ED. Such patients may be at increased risk for future CV events and may profit from intensified therapy to control CV risk factors.

Mediterranean diet reduces endothelial damage and improves the regenerative capacity of endothelium

BACKGROUND

Endothelial dysfunction is a fundamental step in the atherosclerotic disease process. Activation or injury of the endothelium leads to a variety of inflammatory disorders, including the release of microparticles. Endothelial progenitor cells may contribute to the maintenance of the endothelium by replacing injured mature endothelial cells.

OBJECTIVE

We studied the influence of dietary fat on the release of endothelial microparticles (EMPs) and endothelial progenitor cells (EPCs) in elderly subjects.

DESIGN

Twenty healthy, elderly subjects (10 men and 10 women) consumed 3 diets following a randomized crossover design, each for 4 wk: a saturated fatty acid diet; a low-fat, high-carbohydrate diet; and a Mediterranean diet (MedDiet) enriched in monounsaturated fatty acids. We investigated total microparticles, EMPs from activated endothelial cells (activated EMPs), EMPs from apoptotic endothelial cells (apoptotic EMPs), EPCs, oxidative stress variables, and ischemic reactive hyperemia (IRH).

RESULTS

The MedDiet led to lower total microparticle, activated EMP, and apoptotic EMP concentrations and higher EPC numbers than did the other diets (P < 0.001). We detected lower superoxide dismutase activity (P < 0.001), a higher plasma β-carotene concentration (P < 0.001), and lower urinary isoprostane and plasma nitrotyrosine concentrations after consumption of the MedDiet than after consumption of the other 2 diets (P < 0.05). Furthermore, the occurrence of IRH was higher after consumption of the MedDiet than after consumption of the other 2 diets (P < 0.05).

CONCLUSION

Consumption of the MedDiet induces a reduction in endothelial damage and dysfunction, which is associated with an improvement in the regenerative capacity of the endothelium, in comparison with 2 other diets.

Statin therapy in South Asians-facts and future

South Asians have higher overall burden of coronary heart disease. South Asian migrants suffer from more severe and fatal coronary heart disease at younger age despite similar risk factors compared with local population. Elevated blood cholesterol contributes to atherosclerosis and heart disease and is one of the primary modifiable risk factor for these conditions. Since the discovery of a fungal metabolite that inhibits 3-hydroxy-3methyl-glutaryl-coenzyme A reductase, statins have emerged rapidly as the global leader in medical therapeutics designed to lower low-density lipoprotein cholesterol and had reduced mortality and morbidity from coronary heart disease when used for primary or secondary prevention. Despite the considerable burden imposed by cardiovascular disease, South Asians remain inadequately targeted for risk-reduction strategies, including screening and treatment for dyslipidemia.

CD31+/Annexin V+ microparticles in healthy offsprings of patients with coronary artery disease

BACKGROUND

First-degree relatives of patients with premature coronary artery disease (CAD) develop endothelial dysfunction even in the case they are apparently healthy. In this study we wanted to clarify whether reduced blood levels of circulating endothelial progenitor cells (EPCs), an endogenous repair mechanism to replace dysfunctional endothelium, or elevated endothelial-derived microparticles (EMPs), an indicator and a mediator of increased endothelial cell damage/apoptosis, are an initial step in the pathogenesis of endothelial dysfunction in genetically predisposed subjects.

MATERIALS AND METHODS

Fifty-six healthy young men (aged 23 to 31 years) from a fire brigade were enrolled, of which 20 subjects had a positive family history (FH) for premature CAD. Subjects with or without a positive FH did not differ with respect to age, body mass index, risk factors and C-reactive protein. Endothelial function was assessed by hyperaemia-mediated relaxation of the brachial artery, blood levels of EPCs (VEGFR2(+)CD34(+) cells) and number of EMPs (CD31(+(bright))/Annexin V(+) particles) were analysed by flow cytometry.

RESULTS

Hyperaemia-mediated relaxation of the brachial artery was similar in both groups, and the blood levels of EPCs were comparable. However, the number of EMPs were significantly increased in subjects with a positive FH compared to those with a negative FH (neg. FH: 55.31 +/- 4.88 vs. pos. FH: 70.37 +/- 6.32 particles microL(-1 )platelet poor plasma; P < 0.05). Number of EMPs correlate inversely with the FMD response.

CONCLUSIONS

These results suggest that increased plasma levels of EMPs may be an initial step in the development of endothelial dysfunction in genetically predisposed subjects.

Relations of measures of endothelial function and kidney disease: the Framingham Heart Study

BACKGROUND

Endothelial dysfunction is prevalent in individuals with end-stage renal disease. Whether endothelial dysfunction is present in patients with moderate chronic kidney disease (CKD) is uncertain.

STUDY DESIGN

Cross-sectional study.

SETTINGS & PARTICIPANTS

Brachial reactivity measurements were obtained during the seventh examination cycle in 2,818 (diameter measurements) and 2,256 (flow measurements) Framingham Heart Study Offspring cohort participants (53% women; mean age, 61 +/- 9 years).

PREDICTOR

Estimated glomerular filtration rate less than 60 mL/min/1.73 m(2) derived from creatinine- and cystatin C-based estimating equations; microalbuminuria status.

OUTCOME

Brachial reactivity measurements (baseline brachial diameter, flow-mediated dilation, baseline and hyperemic mean flow).

MEASUREMENTS

Linear regression models were used to model brachial measures as a function of CKD and microalbuminuria status.

RESULTS

Overall, 7.3% (n = 206) of participants had CKD, and of 2,301 with urinary measurements, 10.0% (n = 230) had microalbuminuria. Brachial reactivity measures did not differ significantly by CKD status in either creatinine- or cystatin C-based equations in either age- and sex- or multivariable-adjusted models. In age- and sex-adjusted models, microalbuminuria was associated with decreased hyperemic mean flow (47.2 +/- 1.4 versus 51.4 +/- 0.5 mg/g; P = 0.005), but the association was not significant after multivariable adjustment (P = 0.09).

LIMITATIONS

Predominantly white ambulatory cohort; results may not be generalizable to other ethnic groups or individuals with severe CKD.

CONCLUSIONS

Endothelial dysfunction was not a major correlate of CKD in our sample.

A review of methods for assessment of coronary microvascular disease in both clinical and experimental settings

Obstructive disease of the large coronary arteries is the prominent cause for angina pectoris. However, angina may also occur in the absence of significant coronary atherosclerosis or coronary artery spasm, especially in women. Myocardial ischaemia in these patients is often associated with abnormalities of the coronary microcirculation and may thus represent a manifestation of coronary microvascular disease (CMD). Elucidation of the role of the microvasculature in the genesis of myocardial ischaemia and cardiac damage-in the presence or absence of obstructive coronary atherosclerosis-will certainly result in more rational diagnostic and therapeutic interventions for patients with ischaemic heart disease. Specifically targeted research based on improved assessment modalities is needed to improve the diagnosis of CMD and to translate current molecular, cellular, and physiological knowledge into new therapeutic options.

Combined use of endothelial function assessed by brachial ultrasound and high-sensitive C-reactive protein in predicting cardiovascular events

BACKGROUND

Endothelial function plays a key role in determining the clinical manifestations of atherosclerotic lesions. Elevated high-sensitive C-reactive protein (hsCRP) relates to long-term prognosis of cardiovascular disease.

HYPOTHESIS

We test the hypothesis that combined use of endothelial function and hsCRP could increase predictive value of future cardiovascular events.

METHODS AND RESULTS

205 patients were followed up for a median period of 24 months. Endothelial function was assessed using brachial ultrasound to measure endothelium-dependent flow-mediated vasodilation (FMD). Cox regression analyses were conducted for the 205 subjects, with cardiovascular events being defined as myocardial infarction, hospitalization due to congestive heart failure, percutaneous coronary intervention, coronary artery bypass grafting, and ischemic stroke. Twenty nine (14%) developed cardiovascular events. Both FMD and hsCRP were significantly predictive of cardiovascular events (relative risk for patients with FMD<3% as compared to those with FMD>6%, 4.65, 95% confidence interval (CI): 1.30-16.66, p=0.018; relative risk for the highest as compared with the lowest tertile of hsCRP level, 3.59, 95% CI: 1.32-9.74, p=0.012, respectively). Further risk analysis was performed among four groups classified by FMD (FMD >or= 6% or<6%) and half percentile of hsCRP (hsCRP >or= 1 or<1 mg/dL). Relative risks for the FMD<6%/hsCRP >or= 1 mg/dL group compared to FMD >or= 6%/hsCRP<1 mg/dL group increased markedly to 12.598 (95% CI: 1.69 to 94.14, p=0.014) for cardiovascular events.

CONCLUSIONS

Patients with suspected coronary artery disease may benefit from risk stratification based on both endothelium-dependent FMD and hsCRP, since combined these two factors contribute significantly toward the incidence of cardiovascular events.

Mechanisms for the role of tetrahydrobiopterin in endothelial function and vascular disease

NO produced by eNOS (endothelial nitric oxide synthase) is a key mediator of vascular homoeostasis. NO bioavailability is reduced early in vascular disease states, such as hypercholesterolaemia, diabetes and hypertension, and throughout the progression of atherosclerosis. This is a result of both reduced NO synthesis and increased NO consumption by reactive oxygen species. eNOS enzymatic activity appears to be determined by the availability of its cofactor BH4 (tetrahydrobiopterin). When BH4 levels are adequate, eNOS produces NO; when BH4 levels are limiting, eNOS becomes enzymatically uncoupled and generates superoxide, contributing to vascular oxidative stress and endothelial dysfunction. BH4 bioavailability is determined by a balance of enzymatic de novo synthesis and recycling, versus oxidative degradation in dysfunctional endothelium. Augmenting vascular BH4 levels by pharmacological supplementation, by enhancing the rate of de novo biosynthesis or by measures to reduce BH4 oxidation have been shown in experimental studies to enhance NO bioavailability. Thus BH4 represents a potential therapeutic target for preserving eNOS function in vascular disease.

Statin therapy in South-Asian patients: clinical implications beyond lipid lowering?

Whether used as primary or secondary prevention, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) can lead to a significant reduction in mortality and morbidity from cardiovascular disease. Given the benefit in halting atherosclerotic disease progression in patients with stable and acute coronary syndrome, the potential for use in South-Asians remains largely unreported. As this ethnic group has a high rate of coronary events at a younger age, with more extensive and diffuse atheroma, the authors review the impact of statins in relation to observed lipid profiles, as well as novel markers of vascular disease.

The folic acid metabolite L-5-methyltetrahydrofolate effectively reduces total serum homocysteine level in orthotopic liver transplant recipients: a double-blind placebo-controlled study

OBJECTIVE

Hyperhomocysteinemia is a described risk factor of cardiovascular diseases. The aim of this study was the treatment of hyperhomocysteinemia in liver transplant recipients with L-5-methyltetrahydrofolate (L-5-MTHF; 1 mg) vs folic acid (1 mg) vs placebo in a double-blind placebo-controlled study and to compare the relative responsiveness of these patients to L-5-MTHF and folic acid.

SUBJECTS/METHODS

Patients were recruited from Hepatology-Transplantation-Unit at Johann Wolfgang Goethe-University, Frankfurt. Sixty patients were included in this study and 12 patients dropped out for different reasons. The patients were treated over 8 weeks with supplemental L-5-MTHF or folic acid or placebo. Serum homocysteine (HCY) was analyzed with high-performance liquid chromatography (HPLC) beside routine lab tests.

RESULTS

We observed only a significant decrease of total serum HCY in the L-5-MTHF group during the study period (at week 0: 15+/-7.7 microM; after 8 weeks treatment: 9.41+/-2.6 microM, P<0.001). There was no significant decrease of total serum HCY neither in the folic acid group nor in the placebo group.

CONCLUSION

The effects of L-5-MTHF are significantly more potent than folic acid itself. Therefore, lowering serum HCY in liver transplant recipients is effective with L-5-MTHF.

Can intense exercise contribute to cardiovascular disease?

Aerobic exercise is associated with a number of beneficial effects, including reduction in cardiovascular morbidity and mortality, decreased blood pressure, improved insulin sensitivity, weight loss and favorable alterations in lipids. However, intense exercise may have significant deleterious cardiovascular effects. Excessive physical activity may cause increased oxidative stress with resultant endothelial dysfunction and progressive atherosclerosis. Furthermore, intense exercise may promote exercise-induced hypertension that is also associated with endothelial dysfunction and increased cardiovascular mortality. The purpose of this article is to summarize our current understanding of whether intense exercise can contribute to the development of cardiovascular disease.