immunoinflammatory events due to chronic infection are thought to be one of the definitive atherogenetic processes . evidences in favor of this hypothesis are derived from in - vitro experimental and seroepidemiologic studies [ 2 , 3 ] . it is localized within the gastric mucosa leading to life - long inflammation [ 4 , 5 ] . h. pylori has been accused in the pathogenesis of many diseases , either digestive or nondigestive type . one of the most controversial nongastric diseases for that h. pylori held responsible is coronary heart disease [ 610 ] . nitric oxide ( no ) is synthesized from l - arginine by nitric oxide synthase ( nos )   and is a substance that plays an important role in vascular homeostasis regulating vessel tonus . at the same time , it counteracts some vital steps in atherosclerosis such as platelet aggregation , leukocyte - endothelium interaction , and proliferation of vascular smooth muscle cells [ 12 , 13 ] . the evidences derived from in vivo and in vitro studies give rise to think no is a decisive regulatory molecule in atherogenesis and arteriogenesis that are major processes for the formation of collateral arteries [ 1417 ] . asymmetric dimethylarginine ( adma ) is an endogenous competitive inhibitor of endothelial nos and decreases its production and bioavailability . adma is produced by methylation of arginine remnants during normal protein cycle in many tissues including vascular endothelium . a lot of data have recently been published on the importance of adma in endothelial dysfunction as a cardiovascular risk factor [ 2023 ] . in the literature , there are a very few number of studies on serum adma levels in h. pylori infections and those studies reveal somehow controversial results [ 11 , 20 ] . the effects of h. pylori eradication on serum adma levels have not been evaluated recently . in the present study , we were interested to see the effects of h. pylori eradication on serum adma levels . exclusion criteria were prior eradication therapy for h. pylori , antiulcer drug use within last 1 month , gastrointestinal system and other organ malignancies , inflammatory and infectious diseases , and prior gastric surgery . patients with chronic diseases such as ischemic heart disease , diabetes mellitus , or hypertension were not included in the study . eradication therapies consisted of lansoprazole 30  mg ( 2  1/day ) , clarithromycin 500  mg ( 2  1/day ) , and amoxicillin 1000  mg ( 2  1/day ) taken for 2 weeks and used in all participants .   in all the patients , eradication was verified by means of c - urea breath test 2 months after h. pylori eradication treatment . this study was conducted with the permission of the local ethics committee of zonguldak karaelmas university faculty of medicine , zonguldak , turkey . fasting blood samples of the subjects were drawn for the analysis before and 2 months after h. pylori eradication treatment . the blood samples were kept at room temperature for 30  min , and then sera were separated from the cells by centrifugation at 3000  rpm for 5  min . serum adma levels were measured by a commercially available kit ( immun diagnostik ag , bensheim , germany ) based on enzyme - linked immunosorbent assay ( elisa ) method . statistical analyses were performed using the statistical package for the social sciences ( spss , version 13.0 ) . results were expressed as the means  standard deviations . in the comparison between groups , statistically significant differences were assessed by the wilcoxon signed ranks test or paired t tests . forty - two patients with dyspeptic symptoms ( 20 males , 22 females ) with mean age of 39,1  10,6 years ( min 19 , max 54 ) were enrolled into the study . eradication was achieved in 34 ( 81% ) patients . the mean serum adma levels before and after therapy were 1,77   0 , 30 and 1,67  0 , 29  ng / ml in the group with h. pylori eradicated and 1,63  0 , 28 and 1,56   0 , 32  ng / ml in the noneradicated , respectively . we could detect statistically significant decrease in serum adma levels after h. pylori therapy in h. pylori eradicated group ( p < .05 ; table 1 ) . h. pylori is a known causal agent of several gastrointestinal diseases and has also been implicated in ischemic heart disease . however , the role of h. pylori in the pathogenesis of atherosclerosis is controversial and the mechanism in this association is also unclear . several different mechanisms are proposed for the role of h. pylori in ischemic heart disease [ 14 , 9 , 10 , 24 ] .   in the present study , we investigated to see the effects of h. pylori eradication on serum adma levels , an nos inhibitor . the analysis showed that h. pylori eradication was associated with a significant reduction in serum adma levels . in the literature , these are the first data that have shown the effects of h. pylori eradication therapy on serum adma levels .   nitric oxide is a substance derived from an aminoacid , l - arginine , by an endothelial nos enzyme and plays a crucial role in maintaining vascular homeostasis by regulating vessel tonus . adma is a naturally occurring amino acid that has the property of inhibiting the activity of nos . currently available experimental and clinical evidence suggests that even small modifications of circulating adma levels significantly change vascular no production , vascular tone , and systemic vascular resistance [ 26 , 27 ] . elevated adma levels have been detected in a large number of diseases associated with an impaired endothelial l - arginine - no pathway , such as atherosclerosis , hypercholesterolemia , chronic heart failure , type 2 diabetes mellitus , stroke , hyperhomocysteinemia , and hypertension [ 25 , 26 , 28 ] . moreover , adma has recently been shown to be a risk factor for cardiovascular disease [ 29 , 30 ] . h. pylori which is a spiral - shaped gram - negative microorganism causes one of the most prevalent chronic infections worldwide . h. pylori typically leads to a life - long chronic infection in the stomach after exposure . then , it causes active chronic inflammation which is composed of gastric submucosal neutrophilic and monocytic infiltration . h. pylori plays a proinflammatory role by inducing various gastric mucosal mediators regulating the motion of neutrophils and other leukocytes , which leads to gastric mucosal damage and epithelial remodeling [ 6 , 31 , 32 ] . proinflammatory factors could induce oxidative stress to increase adma level in cardiovascular tissues via reduction of dimethylarginine dimethylaminohydrolase ( ddah ) activity that degrades adma [ 11 , 3336 ] . h. pylori infection was proven that oxidative stress [ 3840 ] and cytokine levels like tnf - alpha [ 40 , 41 ] changed in chronic inflammation secondary to inflammatory cell proliferation in gastric mucosa . those changes of cytokine levels and oxidative stress in h. pylori infection might cause adma level elevations . also h. pylori infection might itself produce adma [ 20 , 42 ] . furthermore , chronic h. pylori infection might decrease the absorption of micronutrients , hence , causing an imbalance in homocysteine - methionine system , so increasing methyl reservoir and then adma levels [ 20 , 43 ] . very few studies have been found in the literature stressing on adma levels in h. pylori infection . found that adma levels increased in h. pylori - positive case group compared to negative control . they suggested that eradication of h. pylori might decrease the risk of cardiovascular disease by decreasing serum adma levels . however , they did not investigate the effect of h. pylori eradication on the adma levels .   in another study conducted by zhang et al . , they found adma at high levels in gastric juice of h. pylori - positive cases whereas did not encounter any difference between h. pylori - positive and negative patients with respect to plasma adma levels .   in the present study different from the previous ones we focused that h. pylori eradication significantly decreased the serum adma levels . we have postulated that h. pylori eradication might be important in preventing the diseases , for example , cardiovascular diseases , related to adma by decreasing its serum levels .
introduction . microbial pathogens , one of them is helicobacter pylori ( h. pylori ) , 
 have frequently been implicated in the atherogenesis . 
 endothelium - derived nitric oxide ( no ) is synthesized from l - arginine by nitric oxide synthase ( nos ) and plays a pivotal role in the regulation of vascular tone . 
 asymmetric dimethylarginine ( adma ) is the most potent endogenous nos inhibitor . 
 elevated levels of adma have been reported in many circumstances associated with a high cardiovascular risk . 
 the aim of the present study was to investigate whether the eradication of h. pylori infection affects serum adma levels . 
 materials and methods . 
 forty - two h. pylori - positive patients were enrolled in the study . 
 triple therapy for 14 days were given to all patients . 
 serum adma levels were measured at baseline and 2 months after therapy . results . 
 eradication was achieved in 34 ( 81% ) patients . 
 the mean serum adma levels before and after therapy were 1 , 77  0 , 30 and 1 , 67  0 , 29  ng / ml in the group with h. pylori eradicated and 1 , 63  0 , 28 and 1 , 56  0 , 32  ng / ml in the noneradicated , respectively . 
 we detected statistically significant decreased serum adma levels after therapy in h. pylori eradicated group . 
 conclusion . 
 these findings have indicated that eradication of h. pylori infection may decrease the risk of atherosclerosis and cardiovascular events .