A novel predictor of restenosis and adverse cardiac events: asymmetric dimethylarginine

Elevated asymmetric dimethylarginine level as biomarkers of adverse outcomes in individuals undergoing coronary angiography/percutaneous coronary interventions: a systematic review and meta-analysis

BACKGROUND

No previous systematic review and meta-analysis have comprehensively evaluated the association of asymmetric dimethylarginine (ADMA) level with adverse prognosis in individuals undergoing percutaneous coronary interventions (PCI)/coronary angiography (CAG). The aim of this systematic review and meta-analysis was to assess the predictive value of the elevated ADMA level in individuals undergoing CAG/PCI.

MATERIALS AND METHODS

Two authors independently searched PubMed and Embase databases (up to 31 October 2020) for observational studies investigating the association between circulating ADMA level and adverse outcomes in individuals undergoing CAG/PCI. The predictive value of ADMA was expressed by pooling the multivariable-adjusted risk ratio with 95% confidence intervals (CI) for the highest versus lowest ADMA level.

RESULTS

A total of nine prospective studies with 6374 participants were identified. Compared with those with the lowest ADMA level, patients with the highest ADMA level conferred an increased risk of all-cause mortality (risk ratio, 2.11; 95% CI, 1.38-3.21), cardiovascular mortality (risk ratio, 2.95; 95% CI, 1.14-7.68), major adverse cardiovascular events (risk ratio, 2.10; 95% CI, 1.35-3.27) and restenosis (risk ratio, 4.57; 95% CI, 2.52-8.30), respectively.

CONCLUSIONS

High level of ADMA level is possibly an independent predictor of mortality and cardiovascular events in individuals undergoing CAG/PCI. Detection of blood ADMA level before CAG/PCI may add valuable clinical prognosis information.

Are proton pump inhibitors among the risk factors for acute coronary syndrome? A multi-centric case-control study between patients attending governmental hospitals in western Saudi Arabia

Objectives:

To identify the predictors of acute coronary syndrome (ACS) and to determine the relationship between usage of proton pump inhibitors (PPIs) and the occurrence of a first non-fatal ACS event among patients that attended governmental hospitals in Jeddah, Saudi Arabia.

Methods:

A matched, multi-centric case-control study was performed between January and June of 2015 in Jeddah involving 2 governmental hospitals and the main university hospital. A total of 118 cases aged ≥18 years who were recently diagnosed with ACS were selected. For each case, one control matched by age and gender was selected. Information from an interview questionnaire and from reviewing patients’ medical records was recorded on a standardized data collection sheet.

Results:

Risk factors for ACS and the relationship between usage of PPIs and the occurrence of a first non-fatal ACS event were measured in 236 cases and matched controls. Current smoking (OR: 4.5; 95% CI: 1.92-10.98), excessive body weight (OR: 2.99; 95% CI: 1.38-6.45), and dyslipidemia (OR: 2.51; 95% CI: 1.07-5.84) were the predictors of ACS. Hypertension, diabetes, and moderate-to-high physical activity were associated with ACS. However, there was no statistical association between use of PPIs and occurrence of the first non-fatal ACS event (p>0.05).

Conclusions:

There was no association between PPIs and the occurrence of a first non-fatal ACS event. Smoking, increased weight, and dyslipidemia are considered predictors of ACS. Furthermore, ACS is associated with self-reported diabetes, hypertension, and physical activity.

Systematic review with meta-analysis: risk of adverse cardiovascular events with proton pump inhibitors independent of clopidogrel

BACKGROUND

Clopidogrel's anti-platelet effects may be attenuated by a pharmacokinetic interaction with co-prescribed proton pump inhibitors, which inhibit oxidative pathways that convert clopidogrel into its active metabolites. Despite this, the impact of PPIs on cardiovascular risk in the absence of clopidogrel is not well defined.

AIM

To report on a systematic review and meta-analysis of the association between PPIs and cardiovascular risk, independent of clopidogrel.

METHODS

The databases of MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, and ClinicalTrials.gov were systematically searched in October 2017. The primary outcome was association between PPI monotherapy and any adverse cardiovascular event. The secondary outcome was association between proton pump inhibitor monotherapy and acute myocardial infarction. Studies were excluded if they reported or did not adjust for concomitant anti-platelet therapy or involved participants aged less than 18 years.

RESULTS

A total of 22 studies were included in the systematic review. Data from 16 studies were included in the meta-analysis (involving 447 408 participants). Of these, eight were randomised controlled trials, seven were observational studies and one was a retrospective analysis of a randomised controlled trial. An increased risk of any adverse cardiovascular event with PPI monotherapy was observed using pooled data from observational studies (risk ratio 1.25, 95% CI 1.11-1.42, I² 81%, P < 0.001), but not from randomised controlled trials (risk ratio 0.89, 95% CI 0.34-2.33, I² 0%, P = 0.85).

CONCLUSION

There is no clear evidence of an association between PPI monotherapy and increased cardiovascular risk.

Proton pump inhibitors and the risk of severe adverse events - A cardiovascular bombshell?

Proton pump inhibitors are currently one of the most prescribed pharmacological classes in developed countries, given their effectiveness and safety profile, which has until now been considered favorable. However, in recent years, several papers have been published that associate prolonged use of these drugs with a wide range of adverse effects, posing doubts about their safety. Among the adverse effects described is an increased risk of cardiovascular events. This relationship was first described in subjects after acute coronary syndrome due to the interference of proton pump inhibitors in the cytochrome P450 2C19 and the conversion of clopidogrel to its active metabolite. More recent studies have also reported this relationship with the use of antiplatelet agents that do not depend on cytochrome P450 2C19 activation. The proposed mechanism is inhibition of dimethylarginine dimethylaminohydrolase, a physiological inhibitor of asymmetric dimethylarginine, which increases plasma concentrations of the latter enzyme, leading to lower levels of nitric oxide. By reviewing in this article the relationship between the use of proton pump inhibitors and increased risk of cardiovascular and cerebrovascular events, the authors aim to alert the medical community to the potentially harmful effects of these drugs, and recommend the setting of a moratorium on their prolonged use.

Proton pump inhibitor monotherapy and the risk of cardiovascular events in patients with gastro-esophageal reflux disease: a meta-analysis

BACKGROUND AND PURPOSE

Proton pump inhibitors (PPIs) are commonly used as potent gastric acid secretion antagonists for gastro-esophageal disorders and their overall safety in patients with gastro-esophageal reflux disease (GERD) is considered to be good and they are well-tolerated. However, recent studies have suggested that PPIs may be a potential independent risk factor for cardiovascular adverse events. The aim of our meta-analysis was to examine the association between PPI monotherapy and cardiovascular events in patients with GERD.

METHODS

A literature search involved examination of relevant databases up to July 2015 including PubMed, Cochrane Library, EMBASE, and ClinicalTrial.gov, as well as selected randomized controlled trials (RCTs) reporting cardiovascular events with PPI exposure in GERD patients. In addition, the pooled risk ratio (RR) and heterogeneity were assessed based on a fixed effects model of the meta-analysis and the I² statistic, respectively.

KEY RESULTS

Seventeen RCTs covering 7540 patients were selected. The pooled data suggested that the use of PPIs was associated with a 70% increased cardiovascular risk (RR=1.70, 95% CI: [1.13-2.56], P=.01, I² =0%). Furthermore, higher risks of adverse cardiovascular events in the omeprazole subgroup (RR=3.17, 95% CI: [1.43-7.03], P=.004, I² =25%) and long-term treatment subgroup (RR=2.33, 95% CI: [1.33-4.08], P=.003, I² =0%) were found.

CONCLUSION & INFERENCES

PPI monotherapy can be a risk factor for cardiovascular adverse events. Omeprazole could significantly increase the risk of cardiovascular events and, so, should be used carefully.

Asymmetric Dimethylarginine in Patients with Ascending Aortic Aneurysms

BACKGROUND

Ascending thoracic aortic aneurysm (aTAA) is a heterogeneous group of disorders that involve impaired endothelial function. The nitric oxide (NO) synthase inhibitor asymmetric dimethylarginine (ADMA) serves as an endothelial dysfunction marker. Thus, we investigated ADMA levels in patients with aTAA.

METHODS

Eighty-six patients with aTAA and 18 healthy individuals were enrolled. All patients underwent echocardiography. Plasma ADMA levels were measured using high-performance liquid chromatography.

RESULTS

ADMA levels were higher in aTAA patients than in control patients (p = 0.034). According to the multivariable regression model, higher ADMA levels were associated with ascending aortic diameter (p = 0.017), smoking (p = 0.016), and log-transformed estimated glomerular filtration rate (eGFR, p = 0.005).

CONCLUSION

This pilot study demonstrates an association of ADMA with ascending aortic dilatation; however, further studies are needed to investigate whether increased ADMA levels underlie aTAA development.

Asymmetric and Symmetric Dimethylarginine as Risk Markers for Total Mortality and Cardiovascular Outcomes: A Systematic Review and Meta-Analysis of Prospective Studies

Background

A growing number of studies linked elevated concentrations of circulating asymmetric (ADMA) and symmetric (SDMA) dimethylarginine to mortality and cardiovascular disease (CVD) events. To summarize the evidence, we conducted a systematic review and quantified associations of ADMA and SDMA with the risks of all-cause mortality and incident CVD in meta-analyses accounting for different populations and methodological approaches of the studies.

Methods

Relevant studies were identified in PubMed until February 2015. We used random effect models to obtain summary relative risks (RR) and 95% confidence intervals (95%CIs), comparing top versus bottom tertiles. Dose-response relations were assessed by restricted cubic spline regression models and potential non-linearity was evaluated using a likelihood ratio test. Heterogeneity between subgroups was assessed by meta-regression analysis.

Results

For ADMA, 34 studies (total n = 32,428) investigating associations with all-cause mortality (events = 5,035) and 30 studies (total n = 30,624) investigating the association with incident CVD (events = 3,396) were included. The summary RRs (95%CI) for all-cause mortality were 1.52 (1.37–1.68) and for CVD 1.33 (1.22–1.45), comparing high versus low ADMA concentrations. Slight differences were observed across study populations and methodological approaches, with the strongest association of ADMA being reported with all-cause mortality in critically ill patients. For SDMA, 17 studies (total n = 18,163) were included for all-cause mortality (events = 2,903), and 13 studies (total n = 16,807) for CVD (events = 1,534). High vs. low levels of SDMA, were associated with increased risk of all-cause mortality [summary RR (95%CI): 1.31 (1.18–1.46)] and CVD [summary RR (95%CI): 1.36 (1.10–1.68) Strongest associations were observed in general population samples.

Conclusions

The dimethylarginines ADMA and SDMA are independent risk markers for all-cause mortality and CVD across different populations and methodological approaches.

The Value of Pre- and Post-Stenting Fractional Flow Reserve for Predicting Mid-Term Stent Restenosis Following Percutaneous Coronary Intervention (PCI)

Measuring fractional flow reserve (FFR) in percutaneous coronary intervention (PCI) has predictive value for PCI outcome. We decided to examine the utility of pre- and post-stenting FFR as a predictor of 6-month stent restenosis as well as MACE (major adverse cardiac events). Pre- and post-stenting FFR values were measured for 60 PCI patients. Within 6 months after stenting, all patients were followed for assessment of cardiac MACE including myocardial infarction, unstable angina, or positive exercise test. Stent restenosis was also assessed. Cut-off values for pre- and post-stenting FFR measurements were considered respectively as 0.65 and 0.92. Stent restenosis was detected in 4 patients (6.6%). All 4 patients (100%) with restenosis had pre-stenting FFR of < 0.65, while only 26 of 56 patients without restenosis (46.4%) had pre-stenting FFR value of < 0.65 (P = 0.039). Mean pre-stenting FFR in patients with restenosis was significantly lower than in those without restenosis (0.25 ± 0.01 vs. 0.53 ± 0.03, P = 0.022). Although stent restenosis was higher in patients with post-stenting FFR of < 0.92 (2 cases, 9.5%) than in those with FFR value of ≥ 0.92 (2 cases, 5.1%), the difference was not statistically (P = 0.510). Pre-stenting FFR, the use of longer stents, and history of diabetes mellitus can predict stent restenosis, but the value of post-stenting FFR for predicting restenosis was not explicit.

Increased levels of MMP-3, MMP-9 and MPO represent predictors of in-stent restenosis, while increased levels of ADMA, LCAT, ApoE and ApoD predict bare metal stent patency

AIMS

We sought to identify biochemical predictors that indicate susceptibility to in-stent restenosis (ISR) after coronary artery bare-metal stenting.

METHODS

A total of 111 consecutive patients with post-percutaneous coronary intervention (PCI) in-stent restenosis of a target lesion within 12 months were matched for age, sex, vessel diameter, and diabetes with 111 controls without post-PCI ISR. Plasma or serum levels of biochemical markers were measured: matrix metalloproteinases (MMP) 2, 3, 9; myeloperoxidase (MPO); asymmetric dimethylarginine (ADMA); lipoprotein (a) (Lp[a]); apolipoproteins E and D (ApoE and D); and lecitin-cholesterol acyltransferase (LCAT). Multivariable logistic regression association tests were performed.

RESULTS

Increased plasma MMP-3 (OR: 1.013; 95% CI: 1.004-1.023; P = 0.005), MMP-9 (OR: 1.014; 95% CI: 1.008-1.020; P < 0.0001) or MPO (OR: 1,003; 95% CI: 1.001-1.005; P = 0.002) was significantly associated with increased risk of ISR. Increased levels of ADMA (OR: 0.212; 95% CI: 0.054-0.827; P = 0.026), ApoE (OR: 0.924; 95% CI: 0.899-0.951; P < 0.0001), ApoD (OR: 0.919; 95% CI: 0.880-0.959; P = 0.0001), or LCAT (OR: 0.927; 95% CI: 0.902-0.952; P < 0.0001) was associated with risk reduction. No correlation was found between plasma MMP-2 or Lp (a) and ISR risk.

CONCLUSIONS

Increased levels of MMP-3, MMP-9, and MPO represent predictors of ISR after bare-metal stent implantation. In contrast, increased ADMA, LCAT, and Apo E and D indicate a decreased in-stent restenosis occurrence.

Proton Pump Inhibitor Usage and the Risk of Myocardial Infarction in the General Population

Background and Aims

Proton pump inhibitors (PPIs) have been associated with adverse clinical outcomes amongst clopidogrel users after an acute coronary syndrome. Recent pre-clinical results suggest that this risk might extend to subjects without any prior history of cardiovascular disease. We explore this potential risk in the general population via data-mining approaches.

Methods

Using a novel approach for mining clinical data for pharmacovigilance, we queried over 16 million clinical documents on 2.9 million individuals to examine whether PPI usage was associated with cardiovascular risk in the general population.

Results

In multiple data sources, we found gastroesophageal reflux disease (GERD) patients exposed to PPIs to have a 1.16 fold increased association (95% CI 1.09–1.24) with myocardial infarction (MI). Survival analysis in a prospective cohort found a two-fold (HR = 2.00; 95% CI 1.07–3.78; P = 0.031) increase in association with cardiovascular mortality. We found that this association exists regardless of clopidogrel use. We also found that H₂ blockers, an alternate treatment for GERD, were not associated with increased cardiovascular risk; had they been in place, such pharmacovigilance algorithms could have flagged this risk as early as the year 2000.

Conclusions

Consistent with our pre-clinical findings that PPIs may adversely impact vascular function, our data-mining study supports the association of PPI exposure with risk for MI in the general population. These data provide an example of how a combination of experimental studies and data-mining approaches can be applied to prioritize drug safety signals for further investigation.

Asymmetric dimethylarginine and cardiovascular risk: systematic review and meta-analysis of 22 prospective studies

BACKGROUND

Asymmetric dimethylarginine (ADMA) inhibits the production of nitric oxide, a key regulator of the vascular tone, and may be important in the development of cardiovascular disease (CVD). Our aim was to reliably quantify the association of ADMA and its isomer symmetric dimethylarginine (SDMA) with the risk of CVD outcomes in long-term cohort studies.

METHODS AND RESULTS

Data were collated from 22 prospective studies involving a total of 19 842 participants, which have recorded 2339 CVD, 997 coronary heart disease, and 467 stroke outcomes during a mean follow-up of 7.1 years. In a comparison of individuals in the top with those in the bottom third of baseline ADMA values, the combined risk ratios were 1.42 (95% confidence interval: 1.29 to 1.56) for CVD, 1.39 for coronary heart disease (1.19 to 1.62), and 1.60 for stroke (1.33 to 1.91). Broadly similar results were observed according to participants' baseline disease status (risk ratios for CVD: 1.35 [1.18 to 1.54] in general populations; 1.47 [1.16 to 1.87] in individuals with pre-existing CVD; and 1.52 [1.26 to 1.84] in individuals with pre-existing kidney disease) and by different study characteristics, including geographical location, sample type, assay method, number of incident outcomes, and level of statistical adjustment (all P values>0.05). In contrast, in 8 prospective studies involving 9070 participants and 848 outcomes, the corresponding estimate for SDMA concentration was 1.32 (0.92 to 1.90) for CVD.

CONCLUSIONS

Available prospective studies suggest associations between circulating ADMA concentration and CVD outcomes under a broad range of circumstances. Further research is needed to better clarify these associations, particularly in large general population studies.

Proton pump inhibitors and vascular function: A prospective cross-over pilot study

Proton pump inhibitors (PPIs) are commonly used drugs for the treatment of gastric reflux. Recent retrospective cohorts and large database studies have raised concern that the use of PPIs is associated with increased cardiovascular (CV) risk. However, there is no prospective clinical study evaluating whether the use of PPIs directly causes CV harm. We conducted a controlled, open-label, cross-over pilot study among 21 adults aged 18 and older who are healthy (n=11) or have established clinical cardiovascular disease (n=10). Study subjects were assigned to receive a PPI (Prevacid; 30 mg) or a placebo pill once daily for 4 weeks. After a 2-week washout period, participants were crossed over to receive the alternate treatment for the ensuing 4 weeks. Subjects underwent evaluation of vascular function (by the EndoPAT technique) and had plasma levels of asymmetric dimethylarginine (ADMA, an endogenous inhibitor of endothelial function previously implicated in PPI-mediated risk) measured prior to and after each treatment interval. We observed a marginal inverse correlation between the EndoPAT score and plasma levels of ADMA (r = -0.364). Subjects experienced a greater worsening in plasma ADMA levels while on PPI than on placebo, and this trend was more pronounced amongst those subjects with a history of vascular disease. However, these trends did not reach statistical significance, and PPI use was also not associated with an impairment in flow-mediated vasodilation during the course of this study. In conclusion, in this open-label, cross-over pilot study conducted among healthy subjects and coronary disease patients, PPI use did not significantly influence vascular endothelial function. Larger, long-term and blinded trials are needed to mechanistically explain the correlation between PPI use and adverse clinical outcomes, which has recently been reported in retrospective cohort studies.

Unexpected effect of proton pump inhibitors: elevation of the cardiovascular risk factor asymmetric dimethylarginine

BACKGROUND

Proton pump inhibitors (PPIs) are gastric acid-suppressing agents widely prescribed for the treatment of gastroesophageal reflux disease. Recently, several studies in patients with acute coronary syndrome have raised the concern that use of PPIs in these patients may increase their risk of major adverse cardiovascular events. The mechanism of this possible adverse effect is not known. Whether the general population might also be at risk has not been addressed.

METHODS AND RESULTS

Plasma asymmetrical dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase. Elevated plasma ADMA is associated with increased risk for cardiovascular disease, likely because of its attenuation of the vasoprotective effects of endothelial nitric oxide synthase. We find that PPIs elevate plasma ADMA levels and reduce nitric oxide levels and endothelium-dependent vasodilation in a murine model and ex vivo human tissues. PPIs increase ADMA because they bind to and inhibit dimethylarginine dimethylaminohydrolase, the enzyme that degrades ADMA.

CONCLUSIONS

We present a plausible biological mechanism to explain the association of PPIs with increased major adverse cardiovascular events in patients with unstable coronary syndromes. Of concern, this adverse mechanism is also likely to extend to the general population using PPIs. This finding compels additional clinical investigations and pharmacovigilance directed toward understanding the cardiovascular risk associated with the use of the PPIs in the general population.

Restenosis after PCI. Part 1: pathophysiology and risk factors

Restenosis is a complex disease for which the pathophysiological mechanisms have not yet been fully elucidated, but are thought to include inflammation, proliferation, and matrix remodeling. Over the years, many predictive clinical, biological, (epi)genetic, lesion-related, and procedural risk factors for restenosis have been identified. These factors are not only useful in risk stratification of patients, they also contribute to our understanding of this condition. Furthermore, these factors provide evidence on which to base treatment tailored to the individual and aid in the development of novel therapeutic modalities. In this Review, we will evaluate the available evidence on the pathophysiological mechanisms of restenosis and provide an overview of the various risk factors, together with the possible clinical application of this knowledge.

Association of midregional proadrenomedullin with coronary artery stenoses, soft atherosclerotic plaques and coronary artery calcium

Midregional proadrenomedullin (MR-proADM) is elevated in patients with heart failure and myocardial infarction. The aim of this study was to evaluate the association of MR-proADM with the grade of coronary artery stenosis, presence of coronary artery soft plaques and coronary artery calcification score (CACS), determined by 64-multislice computed tomography (MSCT) in patients without known prior cardiovascular disease. This retrospective study included 107 patients undergoing MSCT for confirmation (or exclusion) of coronary artery disease. MR-proADM levels were measured in all patients. The assessment of coronary artery stenoses, CACS and soft coronary plaques was made by MSCT using known criteria. The MR-proADM [median (25th-75th percentiles)] level was 0.33 (0.21-0.43) nmol/l. The MR-proADM level was 0.28 (0.22-0.40) nmol/l in patients with coronary stenoses ≥50% (n = 23) versus 0.33 (0.27-0.40) nmol/l in patients with coronary stenoses <50% (n = 83, P = 0.59), 0.33 (0.26-0.40) nmol/l in patients with soft plaques (n = 56) versus 0.33 (0.25-0.41) nmol/l in patients without soft plaques (n = 50, P = 0.73) and 0.33 (0.25-0.39) nmol/l in patients with CACS <200 (n = 81) versus 0.32 (0.26-0.44) nmol/l in patients with CACS ≥200 (n = 26, P = 0.77). In multivariate analysis, the MR-proADM level was a significant correlate of coronary artery stenoses [odds ratio (OR) = 0.93; 95% confidence interval (CI) 0.86-0.99; P = 0.026] and soft plaques (OR = 0.94; 95% CI 0.90-0.99; P = 0.015) but not of CACS (OR = 0.98; 95% CI 0.93-1.03; P = 0.36). A decreased MR-proADM level is an independent correlate of the presence of coronary artery disease and of soft atherosclerotic plaques. Patients with decreased MR-proADM levels may need invasive examinations to diagnose more severe forms of coronary artery disease.

Plasma asymmetric dimethylarginine predicts restenosis after coronary angioplasty

INTRODUCTION

Asymmetric dimethylarginine (ADMA) is an endogenous competitive inhibitor of endothelial nitric oxide synthase. Asymmetric dimethylarginine may influence the process of restenosis after coronary angioplasty. The aim of the study was to determine if initial plasma ADMA level could predict restenosis after coronary angioplasty and stenting.

MATERIAL AND METHODS

The study group consisted of 60 consecutive patients (10 women and 50 men, average age 58.9 ±10.4 years old), who underwent percutaneous coronary angioplasty with bare metal stenting for stable coronary artery disease. All patients underwent follow-up coronary angiography after a 6-month period. Patients were divided into two groups, one with restenosis (n = 22), and the other one without restenosis (n = 38). In addition to measuring acknowledged restenosis risk factors, plasma ADMA level was measured before initial angiography.

RESULTS

Asymmetric dimethylarginine plasma level was significantly higher in the group with restenosis than in the group without restenosis (1.94 ±0.94 µmol/l vs. 0.96 ±0.67 µmol/l; p < 0.05). L-arginine/ADMA ratio was also decreased in the group with restenosis, when compared with the group without restenosis (p < 0.05). Multivariate logistic regression revealed that independent restenosis risk factors were characterised by an initially high ADMA level (p < 0.01), advanced age (p < 0.05) and low level of HDL cholesterol (p < 0.05).

CONCLUSIONS

Pre-procedural elevated plasma ADMA level increases the risk of restenosis in patients who underwent coronary angioplasty and stenting with bare metal stents.

Carotid restenosis is associated with plasma ADMA concentrations in carotid endarterectomy patients

BACKGROUND

The aim of this work has been to study the association between plasma asymmetric dimethylarginine (ADMA) concentrations and carotid stenosis in a group of 64 patients undergoing carotid endarterectomy (CEA).

METHODS

Arginine, ADMA and symmetric dimethylarginine (SDMA) were measured using capillary electrophoresis with UV detection. An evaluation of plasma concentrations of total cysteine (tCys) and total homocysteine (tHcy) was also performed.

RESULTS

Pearson's analysis show a positive correlation between ADMA and carotid stenosis (r=0.37, p=0.003), which is also confirmed after stepwise multiple linear regression analysis. ADMA plasma concentrations were significantly associated with tHcy (r=0.40, p=0.001) and to a lesser extent, even if not significantly, with tCys (r=0.23, p=0.07).

CONCLUSIONS

Our data suggest that plasma ADMA is involved in carotid narrowing after CEA intervention. This suggests that this molecule may have an important role in the events that lead to stenosis.

Utility of myocardial fractional flow reserve for prediction of restenosis following sirolimus-eluting stent implantation

Drug-eluting stents reduce restenosis due to neointimal growth suppression. Considering long-term outcomes, it is both difficult and important to predict drug-eluting stent restenosis. Thus, this study was designed to examine the utility of myocardial fractional flow reserve (FFR) as a predictor of sirolimus-eluting stent (SES) restenosis. Thirty-three patients (35 lesions) were enrolled. Upon completion of SES implantation, FFR was obtained under hyperemia. At 8 months of follow-up, coronary angiography revealed that five lesions had restenosis. Percent diameter stenosis (restenosis 68.7 ± 12.8% vs. non-restenosis 68.7 ± 12.4%, p = 0.78) and lesion length (restenosis 15.8 ± 9.4 mm vs. non-restenosis 14.4 ± 9.2 mm, p = 0.60) were similar. At post-intervention, percent diameter stenosis (restenosis 16.4 ± 6.1% vs. non-restenosis 14.0 ± 7.4%, p = 0.48) and minimum stent area (restenosis 6.01 ± 1.08 mm2 vs. non-restenosis 6.27 ± 1.85 mm2, p = 0.92) were also equivalent. However, proximal edge lumen area was smaller (restenosis 4.24 ± 1.40 mm2 vs. non-restenosis 7.73 ± 2.64 mm2, p = 0.004) and FFR was lower in the restenosis group (restenosis 0.81 ± 0.12 vs. non-restenosis 0.92 ± 0.06, p = 0.029). SES patients with restenosis had a lower FFR post stent deployment, suggesting the decreased FFR may be a useful predictor for SES restenosis.

Milk casein-derived tripeptides, VPP and IPP induced NO production in cultured endothelial cells and endothelium-dependent relaxation of isolated aortic rings

Milk casein-derived tripeptides, valyl prolyl proline (VPP), and isoleucyl prolyl proline (IPP) inhibit angiotensin-converting enzyme (ACE) and both fermented milk and proteolytic hydrolysates of milk casein containing these peptides exert blood pressure-lowering effects in animals and humans. On the top of these results, we have recently reported that the hydrolysate of milk casein containing both VPP and IPP improved the vascular endothelial function of subjects with stage I hypertension, enforcing us to elucidate the mechanism of the improvement of endothelial dysfunction by these peptides. For this purpose, we examined the effect of VPP and IPP on induction of nitric oxide (NO) production using cultured vascular endothelial cells and isolated arterial vessels. When both VPP and IPP were added to the medium of cultured endothelial cells at final concentrations of more than 100 nmol/l, the NO(x) (NO(2) and NO(3)) concentration in the medium was significantly higher than that of the control. Moreover, both VPP and IPP induced endothelium-dependent relaxation of isolated aortic rings, and these effects were inhibited by NO synthase inhibitors, K channel inhibitors, and bradykinin B2 receptor antagonists. These lines of results suggested that both VPP and IPP induced production of vasodilative substances including NO.