Generation of Cellular Reactive Oxygen Species by Activation of the EP2 Receptor Contributes to Prostaglandin E2-Induced Cytotoxicity in Motor Neuron-Like NSC-34 Cells.

Amyotrophic lateral sclerosis (ALS) is a devastating motor neuron disease characterized by progressive degeneration of motor neurons in the central nervous system. Prostaglandin E2 (PGE2) plays a pivotal role in the degeneration of motor neurons in human and transgenic models of ALS. We have shown previously that PGE2 directly induces neuronal death through activation of the E-prostanoid (EP) 2 receptor in differentiated NSC-34 cells, a motor neuron-like cell line. In the present study, to clarify the mechanisms underlying PGE2-induced neurotoxicity, we focused on generation of intracellular reactive oxygen species (ROS) and examined the effects of N-acetylcysteine (NAC), a cell-permeable antioxidant, on PGE2-induced cell death in differentiated NSC-34 cells. Dichlorofluorescein (DCF) fluorescence analysis of PGE2-treated cells showed that intracellular ROS levels increased markedly with time, and that this effect was antagonized by a selective EP2 antagonist (PF-04418948) but not a selective EP3 antagonist (L-798,106). Although an EP2-selective agonist, butaprost, mimicked the effect of PGE2, an EP1/EP3 agonist, sulprostone, transiently but significantly decreased the level of intracellular ROS in these cells. MTT reduction assay and lactate dehydrogenase release assay revealed that PGE2- and butaprost-induced cell death were each suppressed by pretreatment with NAC in a concentration-dependent manner. Western blot analysis revealed that the active form of caspase-3 was markedly increased in the PGE2- and butaprost-treated cells. These increases in caspase-3 protein expression were suppressed by pretreatment with NAC. Moreover, dibutyryl-cAMP treatment of differentiated NSC-34 cells caused intracellular ROS generation and cell death. Our data reveal the existence of a PGE2-EP2 signaling-dependent intracellular ROS generation pathway, with subsequent activation of the caspase-3 cascade, in differentiated NSC-34 cells, suggesting that PGE2 is likely a key molecule linking inflammation to oxidative stress in motor neuron-like NSC-34 cells.

Failure of steroid withdrawal guided by 18F-FDG PET in a patient with cardiac sarcoidosis.

A 71-year-old man diagnosed with cardiac sarcoidosis (CS) 11 years previously underwent implantation of an implantable cardioverter defibrillator due to sustained ventricular tachycardia. Over past decade, his condition of CS did not progress on the maintenance steroid dose of 7.5 mg per day. We attempted to taper and discontinue steroids according to the results of fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET). On the basis of the results, we reduced the oral steroid dose slowly. In spite of no abnormal 18F-FDG uptake in the myocardium, advanced atrioventricular conduction block and deterioration of the ventricular pacing threshold occurred during the course of steroid withdrawal. Plasma brain natriuretic peptide (BNP) increased from 94 to 842 pg/ml. It was necessary to add new ventricular and atrial leads to synchronize atrial and ventricular contractions, and the pacing mode for bradycardia was changed to dual-chamber DDD-60 ppm. Fatigue disappeared, and BNP levels decreased to 147 pg/ml. 18F-FDG PET might have a limit to detect small scattered inflammatory foci. This case highlights the need for caution when reducing steroid doses in CS patients, guided by 18F-FDG PET only. .

A young patient with atypical type-B Wolff-Parkinson-White syndrome accompanied by left ventricular dysfunction.

A 15-year-old asymptomatic male patient presented with an electrocardiographic abnormality and left ventricular (LV) dysfunction (left ventricle ejection fraction of 40%) in a physical examination performed 2 years previously. LV dysfunction did not improve despite optimal medical therapy for dilated cardiomyopathy. Twelve-lead electrocardiography revealed a normal PR interval (138 ms) with a small delta-like wave in V2, but not a typical diagnostic wave that could be diagnosed as Wolff-Parkinson-White (WPW) syndrome by an electrocardiogram auto-analysis. Transthoracic echocardiography showed a remarkable asynchronous septal motion. An electrophysiological study was performed to exclude WPW syndrome. An accessory pathway (AP) was revealed on the lateral wall of the right ventricle, and radiofrequency catheter ablation was successfully performed to disconnect the AP. Thereafter, the dyssynchrony disappeared, and LV function improved. The intrinsic atrioventricular nodal conduction was very slow (A-H, 237 ms). The results of electrocardiogram auto-analysis could not be used to confirm the diagnosis of WPW syndrome because of the atypical delta wave. Conduction via the right lateral AP caused electrical dyssynchrony in the LV. This case suggests that atypical delta waves should be evaluated without depending on electrocardiographic auto-analyses in patients with LV dysfunction accompanied by dyssynchrony.

High concentrations of omega-3 fatty acids are associated with the development of atrial fibrillation in the Japanese population.

The favorable effect of fish oils rich in n-3 polyunsaturated fatty acids (PUFAs) on the development of atrial fibrillation (AF) is controversial. The relationship between the serum concentrations of n-3 PUFAs and the incidence of AF is unclear; therefore, in the present study, we aimed to elucidate this relationship. We evaluated the serum concentrations of n-3 PUFAs in 110 patients with AF, 46 patients with ischemic heart disease (IHD) and no AF, and 36 healthy volunteers. Thirty-six patients had a history of IHD (IHD-AF group) and 74 did not (L-AF group). The eicosapentaenoic acid (EPA) levels in the L-AF group were higher than those in the IHD-AF and control groups (117 ± 64, 76 ± 30, and 68 ± 23 µg/ml, respectively); the docosahexaenoic acid (DHA) levels showed the same pattern (170 ± 50, 127 ± 27, and 126 ± 35 µg/ml, respectively). In both the L-AF and IHD-AF groups, the EPA levels in patients with persistent and permanent AF were higher than those in patients with paroxysmal AF (L-AF 131 ± 74 vs. 105 ± 51 µg/ml; IHD-AF 82 ± 28 vs 70 ± 33 µg/ml). Multivariate analysis showed that cases of AF were associated with higher levels of EPA but not DHA. In this Japanese population study, the EPA and DHA levels in patients with L-AF were higher than those in normal subjects. In particular, the EPA level was associated with the incidence of AF. These findings suggest that an excess of EPA might be a precipitating factor of AF.

Hemodialysis-induced P-wave signal-averaged electrocardiogram alterations are indicative of vulnerability to atrial arrhythmias.

BACKGROUND: Atrial fibrillation (AF) is the most common supraventricular arrhythmia, often occurring during hemodialysis (HD). Prolongation of the total filtered P-wave duration (PWD) and reduction of the root mean square voltages for the last 20 ms of the P wave (RMS20) on a P-wave signal-averaged electrocardiogram (P-SAECG) are predictors of AF. We investigated whether HD induces alterations of P-SAECG, and determined the influential factors. METHODS AND RESULTS: Thirty-three end-stage kidney disease patients (66.7 ± 12.6 years, 23 males) undergoing maintenance HD were enrolled in this study. Digital ambulatory P-SAECG monitoring and laboratory examination of serum proteins and ions were carried out before, during, and after the HD sessions. Data were analyzed by multiple regression analysis. PWD was significantly prolonged, and RMS20 significantly reduced, during HD. These values recovered after completion of HD. Multiple regression analysis showed that prolongation of PWD significantly correlated with HD duration and the rate of removal of body fluid. On the other hand, RMS20 significantly correlated with HD duration and blood urea nitrogen variation. CONCLUSIONS: HD resulted in prolongation of PWD and reduction of RMS20, indicating the vulnerability of HD patients to AF. These P-SAECG changes correlated with HD duration and the rate of removal of the body fluid. These findings underline the importance of the control of dialysis variables in the prevention of atrial arrhythmias following HD.

Catheter ablation of non-inducible atrial tachycardia after surgical repair of heart disease.

We present a patient with non-inducible atrial tachycardia (AT) after atriotomy for surgical repair of heart disease who underwent ablation successfully. Using a 3-D mapping system, we presumed the atriotomy site on the lateral right atrial wall by searching for linear double potentials (DP) during sinus/paced rhythm from the coronary sinus, but it was evaluated incompletely. We could verify the edges of the atriotomy scar precisely by pacing from close to the linear DP lesion and the opposite site. After ablation between the presumed atriotomy scar and the inferior vena cava and cavotricuspid isthmus, no AT recurred without anti-arrhythmic drugs.

Torsion analysis in the early detection of anthracycline-mediated cardiomyopathy.

AIMS: Anthracyclines have profound consequences on the structure and function of the heart, which over time cause a cardiomyopathy that leads to congestive heart failure. Early detection of subclinical left ventricular (LV) dysfunction following a low dose of anthracyclines may be a preventive strategy. The aim of this study was to determine torsion analysis using two-dimensional speckle-tracking imaging (STI), useful for detecting early anthracycline-mediated cardiotoxicity. METHODS AND RESULTS: Conventional and Doppler echocardiography images were obtained from 25 patients (mean age 58 ± 11 years) before chemotherapy and 1 and 3 months after treatment. The cumulative anthracycline doses were 98 ± 59 and 170 ± 87 g/m(2) at 1 and 3 months, respectively. After standard echocardiography, LV torsion and twisting velocity profiles from apical and basal short-axis images were analysed using STI. LV dimensions and ejection fraction did not change throughout follow-up. Although isovolumic relaxation time showed prolongation 3 months after chemotherapy, other Doppler indices did not show significant changes. However, significant deteriorations in torsion (P < 0.0001 by ANOVA), twisting rate (P < 0.0001 by ANOVA), and untwisting rate (P < 0.001 by ANOVA) were found 1 month after chemotherapy. A significant negative correlation was observed between cumulative anthracycline doses and torsion (r = -0.524, P < 0.0001). CONCLUSION: LV torsion analysis could be a useful non-invasive approach for early detection of subclinical anthracycline cardiotoxicity.

Risk evaluation for coronary artery disease in patients with impaired glucose tolerance after a successful coronary intervention.

PURPOSE: Patients with coronary artery disease (CAD) often have risk factors that may influence endothelial function. The purpose of this study was to evaluate the endothelial function and its association with coronary risk factors after percutaneous coronary intervention (PCI). MATERIALS AND METHODS: A total of 14 patients with impaired glucose tolerance and CAD underwent positron emission tomography with N-13 ammonia to measure myocardial blood flow (MBF) at rest and during a cold pressor test (CPT), to estimate endothelial function as a percent increase (%increase) of MBF. The results were compared among normal segments (normal), reperfused segments with PCI (PCI), and nonculprit CAD segments without PCI (non-PCI). Correlations between the %increase and major risk factors were also investigated. RESULTS: CPT induced significant increase in MBF in all groups. The %increase of normal, non-PCI, and PCI groups were 33% ± 22%, 21% ± 23%, and 26% ± 23%, respectively. Comparison with risk factors demonstrated significant correlations only in the non-PCI group. Specifically, there were negative correlations between %increase and fasting blood sugar (r = -0.64, P < 0.05), hemoglobin A1c (r = -0.74, P < 0.05), total cholesterol (r = -0.87, P < 0.05), triglyceride (r = -0.71, P < 0.05), and low-density lipoprotein cholesterol (r = -0.92, P < 0.005), respectively. CONCLUSIONS: Although impaired glucose tolerance patients with a PCI-treated coronary stenosis showed preserved response to CPT, the %increase negatively correlated with risk factors in the non-PCI segments. Therefore, coronary risk factors may affect CAD lesions in PCI-treated patients.

Early intervention with rosuvastatin decreases the lipid components of the plaque in acute coronary syndrome: analysis using integrated backscatter IVUS (ELAN study).

BACKGROUND: It has recently become possible to analyze coronary plaque characteristics by using integrated backscatter intravascular ultrasound (IB-IVUS). The aim of this study was to use this modality to evaluate the impact of early intervention with rosuvastatin on both the volume and tissue characteristics of non-culprit plaques in acute coronary syndrome (ACS). METHODS AND RESULTS: Patients with ACS underwent IB-IVUS after percutaneous coronary intervention procedure and were administered rosuvastatin. Follow-up IB-IVUS was recorded 6 months later. We analyzed the changes in plaque burden and tissue characteristics in these patients. Plaque components were classified as calcified, fibrous, and lipid according IB-IVUS. We comprehensively analyzed 20 ACS patients. The low-density lipoprotein-cholesterol levels decreased significantly from 117 ± 34 mg/dl to 73 ± 19 mg/dl (P<0.001) after statin therapy. Comparing the baseline images with the follow-up ones revealed a significant reduction in the plaque burden from 98.4 ± 42.1mm(3)/10mm to 80.2 ± 35.8 mm(3)/10mm (P<0.001) and in the lipid volume from 44.1 ± 29.6 mm(3)/10mm to 28.6 ± 17.8 mm(3)/10mm (P<0.001). With respect to the % lipid volume, the reduction rate at follow-up showed a significant correlation with its baseline value (r=-0.498, P=0.024). CONCLUSIONS: Early intervention with rosuvastatin in ACS patients enabled significant reduction of the non-culprit plaque during 6 months. This regression was mainly due to the decrease in the lipid component of the plaque.

Influence of circumferential pulmonary vein isolation for atrial fibrillation on ST elevation in patient with Brugada syndrome.

We present a patient with Brugada syndrome and paroxysmal atrial fibrillation who underwent circumferential pulmonary vein isolation. His electrocardiogram showed normal sinus rhythm and first-degree AV block (P-R 280 ms) with coved-type ST elevation in V1-2 (+2.0 mm) before ablation. During ablation around the left pulmonary vein ostium, atrial fibrillation, progression of ST elevation (+4.5 mm), and T wave alternans occurred. After right pulmonary vein encirclement was complete, ST elevation improved to +1.0 mm. The following day, the ST segments remained lower than baseline levels.

Transient pseudorestrictive pattern of transmitral flow velocity curve in patients with paroxysmal atrial fibrillation.

BACKGROUND: Early diastolic velocity of the mitral annulus and transmitral flow propagation velocity are reported as more reliable determinants of left ventricular diastolic function in patients with atrial fibrillation than are transmitral Doppler indices. This study aimed to test the hypothesis that transmitral flow curve shows pseudorestrictive pattern during rate-controlled atrial fibrillation. METHODS: Thirteen paroxysmal atrial fibrillation patients were monitored for three phases: before atrial fibrillation, during atrial fibrillation, and after the recovery of atrial fibrillation to sinus rhythm. Standard two-dimensional, color flow, and tissue Doppler echocardiography were performed. We compared the indices of left ventricular diastolic function among the three phases. RESULTS: The early diastolic velocity of transmitral flow increased significantly during atrial fibrillation (before, 0.76 ± 0.19 m/sec; during, 0.86 ± 0.20 m/sec; after recovery to sinus rhythm, 0.73 ± 0.16 m/sec; P < 0.01). The deceleration time of early transmitral diastolic wave decreased during atrial fibrillation (182.5 ± 39.6 ms; 149.1 ± 38.7 ms; 184.0 ± 44.5 ms, respectively, P < 0.01). The early diastolic velocity of the mitral annulus increased during atrial fibrillation (5.37 ± 1.31 cm/sec; 7.29 ± 1.25 cm/sec; 5.37 ± 1.32 cm/sec; respectively, P < 0.01). The transmitral propagation velocity did not change significantly during atrial fibrillation. CONCLUSION: Although conventional Doppler indices showed abnormal relaxation pattern, left ventricular diastolic function was preserved during rate-controlled atrial fibrillation, as determined from early diastolic velocity of the mitral annulus and transmitral flow propagation velocity.

Effect of graft adaptation of the internal mammary artery on longitudinal phasic blood flow velocity characteristics after surgery.

Left internal mammary artery (LIMA) bypass conduits undergo gradual longitudinal flow transition from the proximal to distal segments, and the diastolic/systolic (D/S) ratios of the flow indices can diagnose graft patency. However, the influence of graft adaptation on this has not been studied. We examined 46 patients with LIMA graft to the left anterior descending artery using a Doppler-tipped guidewire in the proximal, middle, and distal segments; 34 had patent LIMAs (group A: new LIMAs; <1 month postoperatively; n = 22 and group B: old LIMAs; ≥1 month postoperatively; n = 12), and 12 had new LIMAs with distal stenosis (group C). In diastole, the time-averaged peak velocities, maximum peak velocities, and velocity-time integrals in each segment were significantly greater in group A than in groups B or C; however, in systole, they did not differ significantly among the three groups. The D/S ratios of the indices in all segments in group A were significantly greater than those in groups B or C; however, they did not differ between groups B and C in any of the segments. Graft adaptation of a patent LIMA, itself, affects the longitudinal flow transition pattern. The D/S ratio of the three indices in the patent old LIMAs did not differ from those in the LIMAs with distal stenosis early after surgery. The timing of LIMA flow assessment must be considered during assessment of the graft patency from the flow velocity patterns.

Dynamic left ventricular outflow tract obstruction due to anemia in a 71-year-old patient with sigmoid septum.

Sigmoid septum, although frequently observed in the elderly, has no pathophysiological significance in general. A 71-year-old woman with sigmoid septum developed acute heart failure because of a significant left ventricular outflow tract obstruction associated with the aggravation of anemia. This report provides the evidence that a hypercontractile cardiac state induced by anemia can be critical, especially in patients with sigmoid septum. Assessment of the left ventricular outflow tract pressure gradient is important in heart failure patients with sigmoid septum and dynamic obstruction.

A case of left atrial involvement of cardiac sarcoidosis manifesting as atrial flutter treated with corticosteroids.

The clinical diagnosis of cardiac sarcoidosis can be elusive, because the clinical manifestations are non-specific, and the sensitivity and specificity of diagnostic modalities are limited. A 60-year-old woman suffered atrial flutter and diffuse thickening of the left atrial wall accompanied with gallium-67 uptake, both of which were successfully treated with corticosteroid therapy. The diagnosis of cutaneous sarcoidosis had been made two years previously; therefore, we diagnosed the patient as having atrial involvement of cardiac sarcoidosis, and discuss here the importance of noninvasive evaluation of cardiac sarcoidosis using echocardiography.

Rationale and design of assessment of lipophilic vs. hydrophilic statin therapy in acute myocardial infarction (the ALPS-AMI) study.

BACKGROUND: Statins reduce the incidence of cardiovascular events in patients with acute myocardial infarction (AMI). Although all statins are equally effective in secondary prevention, there might be certain differences in the effects of lipophilic and hydrophilic statins. Therefore, our aim is to compare the effectiveness of lipophilic atorvastatin and hydrophilic pravastatin in secondary prevention after AMI. METHODS AND RESULTS: This study is a prospective, randomized, open-label, multicenter study of 500 patients with AMI. Patients that have undergone successful percutaneous coronary intervention will be randomly allocated to receive either atorvastatin or pravastatin with the treatment goal of lowering their low-density lipoprotein-cholesterol level below 100 mg/dl for 2 years. The primary endpoint will be death due to any cause, nonfatal MI, nonfatal stroke, unstable angina, or congestive heart failure requiring hospital admission, or any type of coronary revascularization. CONCLUSION: This is the first multicenter trial to compare the effects and safety of lipophilic and hydrophilic statin therapy in Japanese patients with AMI. It addresses an important issue and could influence the use of statin treatment in the secondary prevention of coronary artery disease.

Ilumatobacter fluminis gen. nov., sp. nov., a novel actinobacterium isolated from the sediment of an estuary.

Bacterial strain YM22-133T was isolated from the sediment of an estuary and grew in media with an artificial seawater base. Strain YM22-133T was Gram-positive, aerobic, non-motile and rod shaped. The cell-wall peptidoglycan contained LL-DAP, glycine, alanine and hydroxyglutamate. The predominant menaquinone was MK-9 (H8), with MK-9 (H0), MK-9 (H2), MK-9 (H4) and MK-9 (H6) present as minor menaquinones. The G+C content of the genomic DNA from the strain was 68 mol%. Phylogenetic analysis of the 16S rRNA gene sequence showed that the strain is nearest to Acidimicrobium ferrooxidans DSM 10331T. However, the similarity is relatively low (87.1%) and the physiological characteristics are also different: Acidimicrobium ferrooxidans is thermotolerant and acidophilic. Therefore, strain YM22-133T can be classified as a novel genus and species, Ilumatobacter fluminis gen. nov., sp. nov. (type strain YM22-133T = DSM 18936T = MBIC 08263T).

Coagulation activity is increased in the left atria of patients with paroxysmal atrial fibrillation during the non-paroxysmal period. Comparison with chronic atrial fibrillation.

BACKGROUND: Evaluation of plasma markers of thrombin activity (thrombin-antithrombin III complex: TAT), active fibrinolysis (plasmin-alpha 2-plasmin inhibitor complex: PIC), and platelet activity (platelet factor 4: PF4) is useful for identifying patients with various cardiovascular disorders who are at high risk of thromboembolism. In this study, these markers were investigated in the left atria (LA) of patients with paroxysmal atrial fibrillation (pAF) in the non-paroxysmal period. METHODS AND RESULTS: Patients with pAF (n=10) and chronic AF (cAF) (n=10) were enrolled. TAT, PIC, and PF4 levels were determined in blood samples obtained from the LA of AF patients before radiofrequency catheter ablation. TAT levels were high in both pAF and cAF patients. PF4 levels were slightly elevated in both groups, but there was no significant difference between the groups. On the other hand, PIC levels in both groups were almost within normal limits, again with no significant difference between groups. CONCLUSIONS: Coagulation activity is elevated in the LA of patients with pAF, even in the non-paroxysmal period, so these patients are at high risk of thromboembolism and anticoagulant therapy is indicated.

Noninvasive evaluation of coronary endothelial function following sirolimus-eluting stent implantation by using positron emission tomography.

OBJECTIVE: Several invasive studies have reported delayed reendothelialization and endothelial dysfunction following sirolimus-eluting stent (SES) implantation. We evaluated the changes in coronary endothelial function following SES implantation by using a noninvasive method that involved positron emission tomography and cold pressor testing (CPT). METHODS: The study was conducted on 14 lesions on which percutaneous coronary intervention (PCI) was successively performed. The lesions were classified into 2 groups depending on the PCI performed: the conventional PCI group, in which 7 conventional PCIs (plain old balloon angioplasty or bare-metal stents) were performed, and the SES group, in which 7 SESs were implanted. Coronary endothelial function was defined as the percent increase in the myocardial blood flow (MBF) during CPT. RESULTS: The resting MBF in the segments distal to the PCI sites did not differ between the conventional PCI and SES groups; however, the MBF significantly decreased in the SES group during CPT. CONCLUSIONS: These data suggest that SES implantation induces coronary endothelial dysfunction in the segments distal to the PCI sites.

Anti-beta 1-adrenoreceptor autoantibodies and myocardial sympathetic nerve activity in chronic heart failure.

BACKGROUND: The autoantibodies stimulate the beta1-adrenoreceptors on cardiac myocytes similar to norepinephrine, and are associated with reduced cardiac function. Iodine-123 metaiodobenzylguanidine ((123)I-MIBG) is metabolized similarly to norepinephrine. This study was undertaken to investigate the relationship between cardiac stimulation by anti-beta1-adrenoreceptor autoantibodies and myocardial sympathetic nervous activity in patients with chronic heart failure. METHODS: We screened for the anti-beta1-adrenoreceptor autoantibodies in 52 patients with chronic heart failure by conducting an enzyme-linked immunosorbent assay, and underwent (123)I-MIBG scintigraphy in 27 of the patients. Anterior planar images of (123)I-MIBG were obtained 15 min and 3 h after the injection. We determined the heart to mediastinum radioactivity ratio (H/M), and calculated the rate of washout of (123)I-MIBG from the heart. RESULTS: Patients with New York Heart Association functional class III or IV had higher levels of anti-beta1-adrenoreceptor autoantibodies than those with class I or II (p<0.01). The autoantibody level was significantly correlated with delayed H/M (r=-0.65, p<0.001) and washout rate (r=0.65, p<0.001). Sixteen patients with a cardiac event showed higher levels of the autoantibodies (p<0.05). Cardiac event-free survival was poorer in patients with the autoantibody levels >10 U/ml than that <10 U/ml (log-rank=12.1, p<0.001). CONCLUSION: The anti-beta1-adrenoreceptor autoantibodies are closely associated with cardiac sympathetic nervous activity assessed by (123)I-MIBG and cardiac event in patients with chronic heart failure.

Elevated osteopontin levels in patients with peripheral arterial disease.

This study was carried out to compare concentrations of osteopontin (OPN) and osteoprotegerin (OPG) in peripheral arterial disease (PAD). The study population consisted of 200 consecutive subjects in whom both OPN/OPG and ankle-brachial index were measured. It was found that OPN levels, but not OPG levels, were significantly more increased in patients with PAD than those without PAD. Serum OPN levels were significantly lower in subjects with angiotensin converting enzyme inhibitors or angiotensin II receptor blockers than those without these agents. In this study, it has been demonstrated for the first time that serum OPN levels are related to PAD. Inhibition of renin- angiotensin system could decrease OPN levels and prevent the progression of PAD.