Impact of Advanced Glycation End Products on Endothelial Function and Their Potential Link to Atherosclerosis

The role of advanced glycation end products (AGEs) in cardiovascular diseases is a matter of interest in the last years and the strong association between the action of AGEs on their receptor (RAGE) and atherosclerosis has attracted increased attention. The aim of this chapter is to review the results of our laboratory and others on the molecular mechanisms triggered by AGEs in the endothelium that could participate in the atherosclerotic process. These mechanisms and molecular pathways could be the source of new therapeutic targets against atherosclerosis or vascular disease. Oxidative stress in endothelium induced by AGEs triggers molecular signaling pathways that produce an inflammatory response or even endothelial dysfunction. Adhesion molecules expression at the membranes of endothelial cells as a consequence of this response or induced by other mechanisms involving AGEs mediates the adhesion of leukocytes to endothelium. This adhesion is a key step in the atherogenesis process and the possible involvement of AGE-RAGE axis in this process should be considered as a potential therapeutic target. Finally, potential pharmacological modulation of AGE-RAGE axis activity at the endothelium is suggested, but the specific pharmacological tools available nowadays are missing; respectively, drugs used for the treatment of cardiovascular and metabolic diseases could be helpful for AGE-RAGE axis modulation, thus also affecting endothelial (dys)function

Predictive value of advanced glycation end products for the development of post-infarction heart failure: a preliminary report

Background: Since post-infarction heart failure (HF) determines a great morbidity and mortality, and given the physiopathology implications of advanced glycation end products (AGE) in the genesis of myocardial dysfunction, it was intended to analyze the prognostic value of these molecules in order to predict post-infarction HF development. Methods: A prospective clinical study in patients after first acute coronary syndrome was conducted. The follow-up period was consisted in 1 year. In 194 patients consecutively admitted in the coronary unit for myocardial infarct fluorescent AGE levels were measured. The association between glycaemic parameters and the development of post-infarction HF were analyzed in those patients. Finally, we identified the variables with independent predictor value by performing a multivariate analysis of hazard ratio for Cox regression. Results: Eleven out of 194 patients (5.6%) developed HF during follow-up (median: 1.0 years [0.8 - 1.5 years]). Even though basal glucose, fructosamine and glycated haemoglobin were significant predictive factors in the univariate analysis, after being adjusted by confounding variables and AGE they lost their statistical signification. Only AGE (Hazard Ratio 1.016, IC 95%: 1.006-1.026; p<0,001), together with NT-proBNP and the infarct extension were predictors for post-infarction HF development, where AGE levels over the median value 5-fold increased the risk of HF development during follow-up. Conclusions: AGE are an independent marker of post-infarction HF development risk

Fluorescent Advanced Glycation End Products and Their Soluble Receptor: The Birth of New Plasmatic Biomarkers for Risk Stratification of Acute Coronary Syndrome

Objective: Advanced glycation end products (AGEs) have pathophysiological implications in cardiovascular diseases. The aim of our study was to evaluate the prognostic value of fluorescent AGEs and its soluble receptor (sRAGE) in the context of acute coronary syndrome (ACS), both in-hospital phase and follow-up period. Methods: A prospective clinical study was performed in patients with debut's ACS. The endpoints were the development of cardiac events (cardiac deaths, re-infarction and new-onset heart failure) during in-hospital phase and follow-up period (366 days, inter-quartile range: 273-519 days). 215 consecutive ACS patients admitted to the coronary care unit (62.7±13.0 years, 24.2% female) were included. 47.4% had a diagnosis of ST segment elevation myocardial infarction. AGEs and sRAGE were analysed by fluorescence spectroscopy and competitive ELISA, respectively. Risk scores (GRACE, TIMI, PURSUIT) were calculated retrospectively using prospective data. The complexity of coronary artery disease was evaluated by SYNTAX score. Results: The mean fluorescent AGEs and sRAGE levels were 57.7±45.1 AU and 1045.4±850.0 pg/mL, respectively. 19 patients presented cardiac events during in-hospital phase and 29 during the follow-up. In-hospital cardiac events were significantly associated with higher sRAGE levels (p = 0.001), but not long-term cardiac events (p = 0.365). Regarding fluorescent AGE the opposite happened. After multivariate analysis correcting by gender, left ventricular ejection fraction, glucose levels, haemoglobin, GRACE and SYNTAX scores, sRAGE was significantly associated with in-hospital prognosis, whereas fluorescent AGEs was significantly associated with long-term prognosis. Conclusions: We conclude that elevated values of sRAGE are associated with worse in-hospital prognosis, whereas high fluorescent AGE levels are associated with more follow-up events

Current status of NADPH oxidase researchin cardiovascular pharmacology

The implications of reactive oxygen species in cardiovascular disease have been known for some decades. Rationally, therapeutic antioxidant strategies combating oxidative stress have been developed, but the results of clinical trials have not been as good as expected. Therefore, to move forward in the design of new therapeutic strategies for cardiovascular disease based on prevention of production of reactive oxygen species, steps must be taken on two fronts, ie, comprehension of reduction-oxidation signaling pathways and the pathophysiologic roles of reactive oxygen species, and development of new, less toxic, and more selective nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors, to clarify both the role of each NADPH oxidase isoform and their utility in clinical practice. In this review, we analyze the value of NADPH oxidase as a therapeutic target for cardiovascular disease and the old and new pharmacologic agents or strategies to prevent NADPH oxidase activity. Some inhibitors and different direct or indirect approaches are available. Regarding direct NADPH oxidase inhibition, the specificity of NADPH oxidase is the focus of current investigations, whereas the chemical structure-activity relationship studies of known inhibitors have provided pharmacophore models with which to search for new molecules. From a general point of view, small-molecule inhibitors are preferred because of their hydrosolubility and oral bioavailability. However, other possibilities are not closed, with peptide inhibitors or monoclonal antibodies against NADPH oxidase isoforms continuing to be under investigation as well as the ongoing search for naturally occurring compounds. Likewise, some different approaches include inhibition of assembly of the NADPH oxidase complex, subcellular translocation, post-transductional modifications, calcium entry/release, electron transfer, and genetic expression. High-throughput screens for any of these activities could provide new inhibitors. All this knowledge and the research presently underway will likely result in development of new drugs for inhibition of NADPH oxidase and application of therapeutic approaches based on their action, for the treatment of cardiovascular disease in the next few years

Advanced glycation end-products disrupt human endothelial cells redox homeostasis: new insights into reactive oxygen species production

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