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Concept: Asymmetric dimethylarginine

138

The pathophysiology of cardiac syndrome X is multifactorial and endothelial dysfunction has been implicated as important contributing factor. Asymmetric dimethylarginine (ADMA), characterized as a circulating endogenous inhibitor of nitric oxide synthase, may have been implicated as an important contributing factor for the development of endothelial dysfunction. In this study, we aim to assess the predictive power of ADMA for long-term prognosis in patients with cardiac syndrome X.

Concepts: Endothelium, Nitric oxide, Prognosis, Asymmetric dimethylarginine, Arginine, Syndrome X, Cardiac syndrome X

42

Sitting time (ST) is associated with cardiovascular disease risk factors whereas breaking ST has been reported to be beneficial for reducing cardiovascular risk.

Concepts: Atherosclerosis, Blood vessel, Cardiovascular disease, Asymmetric dimethylarginine

28

The scope of this study is the examination of NO(2)+NO(3), 3-nitrotyrosine (3-NT), S-nitrosothiols (RSNO), arginase activity and asymmetric (ADMA) and symmetric (SDMA) dimethyl-l-arginine concentrations in plasma of MS patients during interferon-β1b therapy.

Concepts: Amino acid, Multiple sclerosis, Nitrogen, Endothelium, Nitric oxide, Asymmetric dimethylarginine, Arginine, Nitric acid

26

Given the prevalence of cardiovascular disease (CVD), early detection is crucial. Although traditional cardiovascular risk factors relate to future CVD, the predictive value of these risk factors can be relatively limited. Contemporary scientific attention has focused on alternative direct measures of arterial function. Based on the ability of the endothelium to acutely dilate in response to an increase in flow, ‘flow mediated dilation’ (FMD) was introduced approximately 20 years ago and is now an established non-invasive index of endothelial function predictive of future cardiovascular events. Recently, ‘low-flow mediated constriction’ (L-FMC) has been proposed as a complementary addition to FMD. The technique is based on the constrictor response to decreased flow and is claimed to improve the sensitivity and specificity of FMD. The aim of this review is to examine literature pertaining to this novel technique and to provide insight into the potential use of L-FMC in future research.

Concepts: Atherosclerosis, Positive predictive value, Negative predictive value, Blood vessel, Cardiovascular disease, Type I and type II errors, Sensitivity and specificity, Asymmetric dimethylarginine

23

Hyperglycemia causes the breakdown of the blood-retinal barrier by impairing endothelial nitric oxide synthase (eNOS) function. Statins have many pleiotropic effects such as improving endothelial barrier permeability and increasing eNOS mRNA stability. The objective of this study was to determine effect of simvastatin on l-arginine transport and NO production under high-glucose conditions in conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB).

Concepts: Cell, Blood vessel, Endothelium, Nitric oxide, Vasodilation, Asymmetric dimethylarginine, Arginine, Nitric oxide synthase

12

The increased incidence of cardiovascular diseases (CVDs) has stimulated research for substances that could improve cardiovascular health. Among them, resveratrol (RES), a polyphenolic compound notably present in grapes and red wine, has been involved in the “French paradox”. RES is known for its antioxidant and anti-inflammatory properties and for its ability to upregulate endothelial NO synthase (eNOS). RES was able to scavenge (•)OH/O₂(•-) and peroxyl radicals, which can limit the lipid peroxidation processes. Moreover, in bovine aortic endothelial cells (BAEC) under glucose-induced oxidative stress, RES restored the activity of dimethylargininedimethylaminohydrolase (DDAH), an enzyme that degrades an endogenous inhibitor of eNOS named asymmetric dimethylarginine (ADMA). Thus, RES could improve (•)NO availability and decrease the endothelial dysfunction observed in diabetes. Preclinical studies have made it possible to identify molecular targets (SIRT-1, AMPK, Nrf2, NFκB…); however, there are limited human clinical trials, and difficulties in the interpretation of results arise from the use of high-dose RES supplements in research studies, whereas low RES concentrations are present in red wine. The discussions on potential beneficial effects of RES in CVDs (atherosclerosis, hypertension, stroke, myocardial infarction, heart failure) should compare the results of preclinical studies with those of clinical trials.

Concepts: Myocardial infarction, Atherosclerosis, Antioxidant, Heart, Cardiovascular disease, Endothelium, Asymmetric dimethylarginine, Polyphenol antioxidant

6

Studies have linked vasomotor symptoms (VMS) to markers of cardiovascular disease (CVD) risk, yet few have considered clinical cardiovascular events. Data suggest that associations may depend upon the age that symptoms occur. We examined associations between VMS and cardiovascular events and endothelial function, considering age of symptom onset.

Concepts: Disease, Death, Atherosclerosis, Blood vessel, The Canon of Medicine, Cardiovascular disease, Symptom, Asymmetric dimethylarginine

6

Results from observational and genetic epidemiological studies suggest that lower serum homocysteine levels are associated with lower incidence of cardiovascular disease (CVD). Numerous randomized controlled trials have investigated the efficacy of lowering homocysteine with folic acid supplementation for CVD risk, but conflicting results have been reported.

Concepts: Epidemiology, Disease, Cardiovascular disease, Randomized controlled trial, Non-infectious disease, Folic acid, Asymmetric dimethylarginine, Homocysteine

6

Objective:The association of coffee consumption with cardiovascular disease remains controversial. Endothelial function is associated with cardiovascular risk. We examined the association between chronic coffee consumption and endothelium function in elderly inhabitants of the island of Ikaria.Methods:The analysis was conducted on 142 elderly subjects (aged 66-91 years) of the Ikaria Study. Endothelial function was evaluated by ultrasound measurement of flow-mediated dilation (FMD). Coffee consumption was evaluated based on a food frequency questionnaire and was categorized as ‘low’ (< 200 ml/day), 'moderate' (200-450 ml/day), or 'high' (> 450 ml/day).Results:From the subjects included in the study, 87% consumed a boiled Greek type of coffee. Moreover, 40% had a ‘low’, 48% a ‘moderate’ and 13% a ‘high’ daily coffee consumption. There was a linear increase in FMD according to coffee consumption (‘low’: 4.33 ± 2.51% vs ‘moderate’: 5.39 ± 3.09% vs ‘high’: 6.47 ± 2.72%; p = 0.032). Moreover, subjects consuming mainly a boiled Greek type of coffee had a significantly higher FMD compared with those consuming other types of coffee beverages (p = 0.035).Conclusions:Chronic coffee consumption is associated with improved endothelial function in elderly subjects, providing a new connection between nutrition and vascular health.

Concepts: Atherosclerosis, Heart, Blood vessel, Cardiovascular disease, Coffee, Endothelium, Endothelial dysfunction, Asymmetric dimethylarginine

3

Nitric oxide (NO) regulates processes involved in sepsis progression, including vascular function and pathogen defense. Direct NO measurement in patients is unfeasible because of its short half-life. Surrogate markers for NO bioavailability are substrates of NO generating synthase (NOS): L-arginine (lArg) and homoarginine (hArg) together with the inhibitory competitive substrate asymmetric dimethylarginine (ADMA). In immune cells ADMA is cleaved by dimethylarginine-dimethylaminohydrolase-2 (DDAH2). The aim of this study was to investigate whether concentrations of surrogate markers for NO bioavailability are associated with sepsis severity.

Concepts: Immune system, Bacteria, Enzyme, Medical terms, Endothelium, Nitric oxide, Asymmetric dimethylarginine, Arginine