Endothelial dysfunction in diabetes mellitus

Diabetes mellitus is associated with an increased risk of cardiovascular disease, even in the presence of intensive glycemic control. Substantial clinical and experimental evidence suggest that both diabetes and insulin resistance cause a combination of endothelial dysfunctions, which may diminish the anti-atherogenic role of the vascular endothelium. Both insulin resistance and endothelial dysfunction appear to precede the development of overt hyperglycemia in patients with type 2 diabetes. Therefore, in patients with diabetes or insulin resistance, endothelial dysfunction may be a critical early target for preventing atherosclerosis and cardiovascular disease. Microalbuminuria is now considered to be an atherosclerotic risk factor and predicts future cardiovascular disease risk in diabetic patients, in elderly patients, as well as in the general population. It has been implicated as an independent risk factor for cardiovascular disease and premature cardiovascular mortality for patients with type 1 and type 2 diabetes mellitus, as well as for patients with essential hypertension. A complete biochemical understanding of the mechanisms by which hyperglycemia causes vascular functional and structural changes associated with the diabetic milieu still eludes us. In recent years, the numerous biochemical and metabolic pathways postulated to have a causal role in the pathogenesis of diabetic vascular disease have been distilled into several unifying hypotheses. The role of chronic hyperglycemia in the development of diabetic microvascular complications and in neuropathy has been clearly established. However, the biochemical or cellular links between elevated blood glucose levels, and the vascular lesions remain incompletely understood. A number of trials have demonstrated that statins therapy as well as angiotensin converting enzyme inhibitors is associated with improvements in endothelial function in diabetes. Although antioxidants provide short-term improvement of endothelial function in humans, all studies of the effectiveness of preventive antioxidant therapy have been disappointing. Control of hyperglycemia thus remains the best way to improve endothelial function and to prevent atherosclerosis and other cardiovascular complications of diabetes. In the present review we provide the up to date details on this subject

Platelet glycoprotein IIb/IIIa receptor blockade in coronary artery disease

Glycoprotein IIb/IIIa inhibitors represent a new promising class of antiplatelet medications. Their use in acute coronary syndromes and for patients undergoing percutaneous coronary intervention has been the subject of a number of large controlled trials using both the intravenous and the oral forms. In this review, we present a systematic overview of these trials

Elevated serum leptin levels in patients with acute myocardial infarction; correlation with coronary angiographic and echocardiographic findings

BACKGROUND: To assess the relationship between serial serum leptin levels in patients with acute myocardial infarction (AMI) who received thrombolysis and the degree of coronary atherosclerosis, coronary reperfusion, echocardiographic findings, and clinical outcome. 51 consecutive patients presenting with AMI were studied. Clinical characteristics including age, sex, body mass index (BMI) and cardiovascular risk factors were recorded. Serial serum leptin levels at the time of admission and subsequently at 0, 6, 12, 24, 36, 60 hours afterwards were obtained. Coronary angiography was performed in 34 patients; the relation between serum leptin levels and evidence of coronary reperfusion as well as the extent of coronary atherosclerosis according to the coronary artery surgery study classification (CASS) were evaluated. Echocardiographic evaluation was performed in all patients. 36 matched patients were enrolled as control group who had serum leptin level 9.4 ± 6.5 ng/ml. RESULTS: The patients mean age was 50.5 ± 10.6 years. There were 47 males and 3 females. 37.1% were diabetics, 23.5% were hypertensive, 21.6% were dyslipidemic and 22.7% were obese (BMI ≥ 30). Leptin concentrations (ng/ml) increased and peaked at the 4th sample (36 hrs) after admission (mean ± SD) sample (1) =9.55 ± 7.4, sample (2) =12.9 ± 8.4, sample (3) =13.8 ± 10.4, sample (4) =18.9 ± 18.1, sample (5) =11.4 ± 6.5, sample (6) =10.8 ± 8.9 ng/ml. There was a significant correlation between serum leptin and BMI (r = 0.342; p = 0.03). Leptin levels correlated significantly to creatine kinase level on the second day (r = 0.43, p ≤ 0.01). Significant correlation of mean serum leptin with the ejection fraction (P < 0.05) was found. No difference in timing of peak serum leptin between patients who achieved coronary reperfusion vs. those who did not (p = 0.8). There was a trend for an increase in the mean serum leptin levels with increasing number of diseased vessels. There was no correlation between serum leptin levels and outcome neither during the hospitalization nor at 9 months follow up. CONCLUSION: Serum leptin levels increase after myocardial infarction. Serum leptin level may be a predictor of the left ventricular ejection fraction and the degree of atherosclerosis but not of coronary reperfusion

Inflammatory cytokines and atrial fibrillation: current and prospective views

Atrial fibrillation (AF) is the most common sustained arrhythmia and a challenging clinical problem encountered in daily clinical practice. There is an increasing body of evidence linking inflammation to a broad spectrum of cardiovascular conditions including AF. Historical evidence supports an association between AF and inflammation and is consistent with the association of AF with inflammatory conditions of the heart, such as myocarditis and pericarditis. AF has been associated with myocardial oxidative stress, and antioxidant agents have demonstrated antiarrhythmic benefit in humans. Increased plasma interleukin (IL)-6, C-reactive protein (CRP), and plasma viscosity support the existence of an inflammatory state among “typical” populations with chronic AF. These indexes of inflammation are related to the prothrombotic state and may be linked to the clinical characteristics of the patients (underlying vascular disease and comorbidities), rather than simply to the presence of AF itself. It has been suggested that inflammation may have a role in the development of atrial arrhythmias after cardiac surgery, and that a genetic predisposition to develop postoperative complications exists. Cytokines can have a prognostic significance; IL-6 levels, CRP, and other cytokines may have prognostic value in AF. Cytokine lowering therapies, statins, angiotensin converting enzyme inhibitors and other anti-inflammatory agents may have a role in the treatment of AF. The present article provides an overview of the evidence linking inflammatory cytokines to AF and their therapeutic and prognostic implications

Diabetes-related cardiovascular and economic burden in patients hospitalized for heart failure in the US: a recent temporal trend analysis from the National Inpatient Sample

We aimed to study the cardiovascular and economic burden of diabetes mellitus (DM) in patients hospitalized for heart failure (HF) in the US and to assess the recent temporal trend. Data from the National Inpatient Sample were analyzed between 2005 and 2014. The prevalence of DM increased from 40.4 to 46.5% in patients hospitalized for HF. In patients with HF and DM, mean (SD) age slightly decreased from 71 (13) to 70 (13) years, in which 47.5% were males in 2005 as compared with 52% in 2014 (p trend < 0.001 for both). Surprisingly, the presence of DM was associated with lower in-hospital mortality risk, even after adjustment for confounders (adjusted OR = 0.844 (95% CI [0.828–0.860]). Crude mortality gradually decreased from 2.7% in 2005 to 2.4% in 2014 but was still lower than that of non-diabetes patients’ mortality on a yearly comparison basis. Hospitalization for HF also decreased from 211 to 188/100,000 hospitalizations. However, median (IQR) LoS slightly increased from 4 (2–6) to 4 (3–7) days, so did total charges/stay that jumped from 15,704 to 26,858 USD (adjusted for inflation, p trend < 0.001 for both). In total, the prevalence of DM is gradually increasing in HF. However, the temporal trend shows that hospitalization and in-hospital mortality are on a descending slope at a cost of an increasing yearly expenditure and length of stay, even to a larger extent than in patient without DM

Lipidomics for the Prediction of the Unstable Coronary Plaque

Plaques that build up in the lining of the coronary arteries are made up of lipids, inflammatory cells, smooth muscle cells and connective tissue. Thormbosis of a not necessarily occlusive but unstable plaque most often causes episodes of unstable angina and myocardial infarction (MI). Preventing this sudden and adverse event seems to be the only effective startegy to reduce mortality and morbidity of coronary artery disease (CAD). Countries in the Middle East bear a heavy burden from cardiovascular disease. The population of Qatar is particularly prone to CAD with patients presenting with MI at a young age. The prevalence of CAD is in turn promoted by risk factors such as smoking, hypertension, dyslipidemia, diabetes and sedentary lifestyles. Metabolomics approaches to the identification of disease biomarkers rely principally on the comparitive analysis of metabolite expression in normal and disease patients, animal models or cell cultures to identify aberrantly expressed proteins or concentration changes in metabolites that may represent new biomarkers or elucidate a disease mechanism. Lipidomics is the global identification and quantification of a diverse range of lipids in biological systems and is a subset field in metabolomics. The eukaryotic lipidome might compise of 10,000 to 100,000 individual species of lipids originating from a few hundred lipid classes. These lipids are distributed as part of biological membranes, energy storage substances and sometimes function as signal transducers. Altered lipid metabolism and dyslipidemia in the context of inflammation and oxidative stress are driving forces in the transition from stable to unstable plaques. Therefore, a characteristic lipid signature within unstable human plaques and also in the circulating blood plasma could be a predictor of an oncoming cardiac event. This ongoing study was conducted on samples volunteered by acute coronary syndrome (ACS) patients at the Heart Hospital, Doha, Qatar. ACS is a term that describes any condition brought on by the sudden reduced blood flow to the heart due to thrombosis in the coronary arteries and encompasses unstable angina (UA) and both ST-segment elevation (STEMI) and non ST-segment elevation myocardial infarction (NSTEMI). A complete occlusive thrombi leads to extensive myocardial cell death and typically produces an elevated ST-segment in the electrocardiogram. In UA, ischemia occurs unpredictably and suddenly and is caused by the temporary formation of blood clots within the coronary arteries. Unstable angina often occurs before a MI. Distinguished from ACS are patients with stable angina (SA) who develop symptoms due to exertional ischemia. The aim of this study was to profile the global individual lipid levels of subjects in Qatar with unstable CAD, comparing global lipid levels between patients with unstable angina and ST-elevated myocardial infarction. We chose to discover the lipid biomarkers using a workflow utilizing tandem mass spectrometry with on-line ultra-high pressure liquid chromatography (UPLC-MS/MS). Mass spectrometry is a powerful technique that can be used to identify unknown compounds, to quantify known materials and to elucidate the structure and chemical properties of molecules. Recent advances in the accuracy and speed to the technology allow data acquisition for the global analysis of proteins, lipids and metabolites from complex samples such as blood plasma or serum. As we were trying to discover a new lipid biomarker, a technique that would maximise the number of compounds detected, identified and quantified them was favourable. Once the samples were analysed by tandem mass spectrometry, the ion intensity data from each sample was aligned with each other by retention time and lipid mass, normalised and deconvoluted. The signals were then attributed to a particular lipid species by utilising a lipid database and comparing the mass of the detected lipid and piecing together information gained from the fragment data of that lipid from the orbitrap. Statistical analyses of the signals for each individual lipid were then conducted by comparing within group percent coefficient of variation (?CV), fold change and analysis of variance (ANOVA) tests between sample groups and q-value and power calculations. Principal component analysis (PCA) was conducted in order to differentiate the samples under supervised conditions into STEMI and UA groups. A total of 1,663 and 874 lipid compounds were identified in positive and negative modes of mass spectrometry respectively. Of these, 7 compounds showed a significant change (ANOVA p-value < or equal to 0.001) between the STEMI and UA groups. The identities of these compounds are yet to be elucidated. Of the compounds with a significant change between sample groups of ANOVA p-value < or equal to 0.005, five compounds were able to be identified by mass and spectral matching with a lipid database. The PCA scores plot, which distributes samples in multi-dimensional space according to the variance seen in each principal component, showed very low evidence of discrimination between the sample groups with sample scores clustered in a single mixed pattern. This analysis suggests that the lipid abundance changes between the sample groups were difficult to find. This was most likely due to a combination of two reasons: (1) large within-group biological variance that needs to be overcome to detect the between-group variances and (2) the low differences in lipid concentrations between the sample groups. With a greater number of samples, this results is expected to change as the power of the study would increase. Successful results obtained from this study will aid healthcare professional in intervening with appropriate treatment in persons showing no symptoms but are under threat of developing angina or acute MI. The discovery of a lipid biomarker could assist healthcare professionals in prevention of an acute cardiac event thereby saving lives.qscienc

Peripheral Arterial Disease in Patients Presenting with Acute Coronary Syndrome in Six Middle Eastern Countries

To describe prevalence and impact of peripheral arterial disease (PAD) in patients with acute coronary syndrome (ACS), data were collected over 5 months from 6 Middle Eastern countries. Patients were divided into 2 groups (with and without PAD). Out of 6705 consecutive ACS patients, PAD was reported in 177 patients. In comparison to non-PAD, PAD patients were older and more likely to have cardiovascular risk factors. They were more likely to have high Killip class, high GRACE risk score, and non-ST elevation ACS (NSTEACS) at presentation. Thrombolytics, antiplatelet use, and coronary intervention were comparable in both groups. When presented with ST-elevation myocardial infarction (STEMI), patients with PAD had worse outcomes, while in NSTEACS; PAD was associated with higher rate of heart failure in comparison to non-PAD patients. In diabetics, PAD was associated with 2-fold increase in mortality when compared to non-PAD (P = 0.028). After adjustment, PAD was associated with high mortality in STEMI (adjusted OR 2.6; 95% CI 1.23–5.65, P = 0.01). Prevalence of PAD in ACS in the Gulf region is low. Patients with PAD and ACS constitute a high risk group and require more attention. PAD in patients with STEMI is an independent predictor of in-hospital death