Group V Secretory Phospholipase A2 Regulates Endocytosis of Acetylated LDL by Transcriptional Activation of PGK1 in RAW264.7 Macrophage Cell Line.

AIMS: It was suggested that group V secretory phospholipase A2 (sPLA2-V) existed in the nucleus. This study examined whether nuclear sPLA2-V plays a role in endocytosis of acetylated low-density lipoprotein (AcLDL) in monocyte/macrophage-like cell line RAW264.7 cells. METHODS: RAW264.7 cells were transfected with shRNA vector targeting sPLA2-V (sPLA2-V-knockdown [KD] cells) or empty vector (sPLA2-V-wild-type [WT] cells). AcLDL endocytosis was assessed by incubation with 125I-AcLDL or AcLDL conjugated with pHrodo. Actin polymerization was assessed by flow cytometry using Alexa Fluor 546-phalloidin. RESULTS: In immunofluorescence microscopic studies, sPLA2-V was detected in the nucleus. ChIP-Seq and ChIP-qPCR analyses showed binding of sPLA2-V to the promoter region of the phosphoglycerate kinase 1 (Pgk1) gene. In the promoter assay, sPLA2-V-KD cells had lower promoter activity of the Pgk1 gene than sPLA2-V-WT cells, and this decrease could be reversed by transfection with a vector encoding sPLA2-V-H48Q that lacks enzymatic activity. Compared with sPLA2-V-WT cells, sPLA2-V-KD cells had decreased PGK1 protein expression, beclin 1 (Beclin1) phosphorylation at S30, and class III PI3-kinase activity that could also be restored by transfection with sPLA2-V-H48Q. sPLA2-V-KD cells had impaired actin polymerization and endocytosis, which was reversed by introduction of sPLA2-V-H48Q or PGK1 overexpression. In sPLA2-V-WT cells, siRNA-mediated depletion of PGK1 suppressed Beclin1 phosphorylation and impaired actin polymerization and intracellular trafficking of pHrodo-conjugated AcLDL. CONCLUSIONS: Nuclear sPLA2-V binds to the Pgk1 gene promoter region and increases its transcriptional activity. sPLA2-V regulates AcLDL endocytosis through PGK1-Beclin1 in a manner that is independent of its enzymatic activity in RAW264.7 cells.

Glutaredoxin-1 levels in plasma can predict future events in patients with cardiovascular diseases.

Reactive oxygen species that increase during cardiovascular disease (CVD) react with protein cysteine residues to form a glutathione adduct by S-glutathionylation, which is selectively removed by glutaredoxin-1 (Glrx). We previously showed that S-glutathionylation and Glrx play important roles in mouse models of CVD, such as heart failure and peripheral artery disease models. However, there are few clinical studies on Glrx in CVD. Although Glrx is a cytosolic protein expressed in various organs, it is detectable in human plasma. Studies have reported that Glrx in plasma is a potential disease maker, such as CVD and chronic kidney disease and diabetes, however, it remains unclear whether Glrx is related to the prognosis of patients with CVD. The purpose of this study was to elucidate whether Glrx levels in plasma are associated with future events in patients with CVD. Plasma levels of Glrx were measured in 555 patients with CVD who underwent cardiac catheterization using enzyme-linked immunosorbent assay. All patients were followed prospectively for ≤36 months or until occurrence of adverse events, including all-cause death, non-fatal myocardial infarction, and worsening heart failure. During a mean follow-up period of 33 months, 54 adverse events occurred. Kaplan-Meier analysis showed that higher levels of Glrx (>0.622 ng/mL, determined by receiver-operating characteristic curve) resulted in a higher probability for adverse events compared with lower levels of Glrx (≤0.622 ng/mL) (P < 0.01, log-rank test). Multivariate Cox proportional hazards analysis showed that Glrx was a significant predictor of adverse events after adjustment for known risk factors. In conclusion, levels of plasma Glrx >0.662 ng/mL can predict future events in patients with CVD.

Evaluation of renal tubulointerstitial damage as a residual renal risk factor for adverse cardiac events in patients with myocardial infarction.

BACKGROUND: Renal dysfunction, defined as a lower estimated glomerular filtration rate (eGFR), has been shown to be related to cardiovascular events in patients with myocardial infarction (MI). However, the contribution of renal tubulointerstitial damage to the predictive value for cardiovascular events has not been established. The aim of this study was to elucidate whether renal tubulointerstitial damage is associated with the occurrence of cardiac death and recurrence of MI in patients who have had MI. METHODS AND RESULTS: Urinary ß2-microglobulin (ß2MG) was measured in 681 consecutive patients with MI in our hospital. All patients were followed up for <12 years or until the occurrence of cardiac death and MI. During a median follow-up period of 6 years, the cumulative cardiac death rate was 5.4%, and the MI rate was 3.1%. When outcomes were divided into two groups according to the ß2MG levels, cardiac death and MI rates were lower in patients with lower levels of ß2MG (<0.319 mg/gCre: determined by receiver operating characteristic analyses) than in those with ß2MG ≥0.319 mg/gCre (5.9% versus 17.1%, p<0.01). When outcomes were stratified according to the ß2MG levels in combination with eGFR levels, Kaplan-Meier analyses showed that cardiac death and MI rates increased depending on an increase in the ß2MG levels (p<0.05). Moreover, multivariate Cox analyses revealed that high levels of ß2MG were a significant independent predictor of adverse events (hazard ratio: 1.956; 95% confidence interval: 1.014-3.774; p = 0.045). The addition of high levels of ß2MG to conventional risk factors, including eGFR and urinary albumin, improved the net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (NRI 0.5447, p = 0.0002; IDI 0.0126, p = 0.0454). CONCLUSION: Renal tubulointerstitial damage, as assessed by urinary ß2MG, is associated with the occurrence of cardiac death and recurrence of MI independent of renal glomerular function in patients with MI.

Persistent Myocardial Production of Follistatin-like 1 Is Associated With Left Ventricular Adverse Remodeling in Patients With Myocardial Infarction: Myocardial production of FSTL1 in AMI patients.

BACKGROUND: Although animal studies showed that Follistatin-like 1 (FSTL1) exerts cardioprotective effects against ischemic injury, little is known in humans. We examined whether FSTL1 is secreted in an infarcted myocardium and whether its production is associated with left ventricular (LV) remodeling in survivors of acute myocardial infarction. METHODS AND RESULTS: FSTL1 levels were measured by enzyme-linked immunosorbent assay in plasma collected from the aortic root and the anterior interventricular vein in 93 patients with anterior acute myocardial infarction. Measurement of FSTL1 levels and left ventriculography were repeated during the early phase (2 weeks) and the chronic phase (6 months) after MI. A persistent increment in FSTL1 levels from the aortic root to the anterior interventricular vein, reflecting FSTL1 production in the infarcted myocardium at both the early and chronic phases, was seen in 22 patients (24%). A linear regression analysis revealed that a persistent transmyocardial increment in FSTL1 levels was significantly associated with percent changes in LV end-diastolic volume index, LV end-systolic volume index, and LV ejection fraction from the early to the chronic phase (r = 0.44, 0.51, and -0.43, respectively, all P < .001). CONCLUSIONS: The persistent production of FSTL1 in the infarcted myocardium was associated with adverse LV remodeling in survivors of acute myocardial infarction.

Protein S-glutathionylation stimulate adipogenesis by stabilizing C/EBPß in 3T3L1 cells.

Reactive oxygen species (ROS) increase during adipogenesis and in obesity. Oxidants react with cysteine residues of proteins to form glutathione (GSH) adducts, S-glutathionylation, that are selectively removed by glutaredoxin-1 (Glrx). We have previously reported that Glrx knockout mice had increased protein S-glutathionylation and developed obesity by an unknown mechanism. In this study, we demonstrated that 3T3L1 adipocytes differentiation increased ROS and protein S-glutathionylation. Glrx ablation elevated protein S-glutathionylation and lipid content in 3T3L1 cells. Glrx replenishment decreased the lipid content of Glrx KO 3T3L1 cells. Glrx KO also increased protein expression and protein S-glutathionylation of the adipogenic transcription factor CCAAT enhancer-binding protein (C/EBP) ß. Protein S-glutathionylation decreased the interaction of C/EBPß and protein inhibitor of activated STAT (PIAS) 1, a small ubiquitin-related modifier E3 ligase that facilitates C/EBPß degradation. Experiments with truncated mutant C/EBPß demonstrated that PIAS1 interacted with the liver-enriched inhibitory protein (LIP) region of C/EBPß. Furthermore, mass spectrometry analysis identified protein S-glutathionylation of Cys201 and Cys296 in the LIP region of C/EBPß. The C201S, C296S double-mutant C/EBPß prevented protein S-glutathionylation and preserved the interaction with PIAS1. In summary, Glrx ablation stimulated 3T3L1 cell differentiation and adipogenesis via increased protein S-glutathionylation of C/EBPß, stabilizing and increasing C/EBPß protein levels.

Deficiency of Phospholipase A2 Receptor Exacerbates Autoimmune Myocarditis in Mice.

Secretory phospholipase A2 (sPLA2) plays a critical role in the pathogenesis of various inflammatory diseases through production of pro-inflammatory eicosanoids. PLA2 receptor 1 (PLA2R) acts as a clearance receptor for sPLA2s. This study examined whether PLA2R plays a role in the pathogenesis of experimental autoimmune myocarditis using PLA2R-deficient (PLA2R KO) mice on a BALB/c background. Autoimmune myocarditis was induced by immunization with murine α-myosin heavy chain. In the immunostaining of PLA2R wild-type (WT) myocardium, PLA2R and sPLA2s were expressed in α-SMA+ cells and neutrophils, respectively. In immunoblot analyses, tissue from PLA2R KO myocardium after immunization had five to tenfold increases in the protein level of sPLA2-IB and sPLA2-IIA compared with PLA2R WT myocardium. However, the mRNA expression levels of these sPLA2s were similar in PLA2R KO and WT myocardium. Compared with PLA2R WT myocardium, PLA2R KO myocardium after immunization showed 40% increase in areas affected by infiltration of inflammatory cells, eight to tenfold increase in levels of PGE2 and TXB2, and a threefold increase in number of Th17 cells in heart infiltrates assessed by flow cytometric analysis. Finally, PGE2 promoted IL-23-induced expansion of Th17 cells in vitro. In conclusion, PLA2R-deficiency increased sPLA2-IB and sPLA2-IIA levels in the myocardium after immunization probably through impaired clearance, leading to increased levels of PGE2 in the myocardium. Elevated PGE2 induced Th17 cell expansion, exacerbating myocarditis in PLA2R KO mice. Thus, PLA2R plays an important role in pathogenesis of experimental autoimmune myocarditis.

Remnant Lipoproteins Are Residual Risk Factor for Future Cardiovascular Events in Patients With Stable Coronary Artery Disease and On-Statin Low-Density Lipoprotein Cholesterol Levels <70 mg/dL.

BACKGROUND: This study examined the predictive value of remnant lipoprotein levels for cardiovascular events (CVEs) in patients with stable coronary artery disease (CAD) and low-density lipoprotein cholesterol (LDL-C) levels <70 mg/dL on statin treatment.Methods and Results:Serum levels of remnant lipoproteins (remnant-like lipoprotein particles cholesterol: RLP-C) were measured by an immunoseparation method in 247 consecutive patients with CAD who had on-statin LDL-C levels <70 mg/dL. All the patients were followed prospectively for a period of ≤60 months or until the occurrence of the primary composite endpoint of cardiac death, nonfatal myocardial infarction, unstable angina requiring coronary revascularization, worsening heart failure, peripheral artery disease, aortic event, and ischemic stroke. During a mean follow-up period of 38 months, 33 CVEs occurred. Kaplan-Meier analysis demonstrated that higher RLP-C levels (≥3.9 mg/dL, determined by ROC curve) resulted in a significantly higher probability for the primary endpoint than did lower RLP-C levels (<3.9 mg/dL) (P<0.01 by log-rank test). Stepwise multivariate Cox proportional hazard analysis showed that RLP-C was a significant predictor of the primary endpoint after adjustment for known risk factors and lipid variables including triglycerides, and total apolipoprotein B (hazard ratio 1.62, 95% confidence interval 1.26-2.07, P<0.01). CONCLUSIONS: RLP-C levels are a residual risk factor for future CVEs in patients with CAD and on-statin LDL-C <70 mg/dL.

Persistent Dysfunction of Coronary Endothelial Vasomotor Responses is Related to Atheroma Plaque Progression in the Infarct-Related Coronary Artery of AMI Survivors.

AIM: Although coronary endothelial vasomotor dysfunction predicts future coronary events, there are few human studies showing the relationship between endothelial vasomotor dysfunction and atheroma plaque progression in the same coronary artery. This study examined whether endothelial vasomotor dysfunction is related to atheroma plaque progression in the infarct-related coronary artery of ST-segment elevation myocardial infarction (STEMI) survivors using serial assessment of coronary plaque size with intravascular ultrasound (IVUS) and coronary vasomotor responses to acetylcholine (ACh). METHODS: This study included 50 patients with a first acute STEMI due to occlusion of the left anterior descending coronary artery (LAD) and successful reperfusion therapy with percutaneous coronary intervention (PCI). IVUS and vasomotor response to ACh in the LAD were measured within two weeks of acute myocardial infarction (AMI) (1st test) and repeated six months (2nd test) after AMI under optimal anti-atherosclerotic therapies. RESULTS: Percent atheroma volume (PAV) and total atheroma volume (TAV) in the LAD progressed over six months of follow-up in 18 and 14 patients, respectively. PAV and TAV progression was significantly associated with persistent impairment of epicardial coronary artery dilation and coronary blood flow increase in response to ACh at both the 1st and 2nd tests. PAV and TAV progression had no significant association with traditional risk factors, PCI-related variables, medications, and the coronary vasomotor responses to sodium nitroprusside, an endothelium-independent vasodilator. CONCLUSIONS: Persistent impairment of endothelial vasomotor function in the conduit arterial segment and the resistance arteriole was related to atheromatous plaque progression in the infarct-related coronary arteries of STEMI survivors.

High levels of stromal cell-derived factor-1α predict short-term progression of renal dysfunction in patients with coronary artery disease.

BACKGROUND: Stromal cell-derived factor-1α (SDF-1α) is an inflammatory chemokine that plays a critical role in cardiovascular disease. Although persistent inflammation causes renal dysfunction, it remains unclear whether SDF-1α is related to progression of chronic kidney disease. This study examined whether high levels of SDF-1α are associated with future declines in renal function in patients with coronary artery disease (CAD). METHODS: Plasma levels of SDF-1α in the peripheral blood were measured by enzyme-linked immunosorbent assay in 344 patients with CAD. All patients were followed for 24 months or until the occurrence of renal dysfunction, defined as ≥ 25% decrease in estimated glomerular filtration rate (eGFR) from baseline. RESULTS: During the follow-up period, 36 patients developed renal dysfunction. Multivariate logistic regression analysis showed that high plasma levels of SDF-1α were significantly associated with progression of renal dysfunction (odds ratio 1.65; 95% confidence intervals 1.07-2.35, p = 0.03). In addition, high plasma levels of SDF-1α had a significant incremental effect on the predictive value of known risk factors for renal dysfunction in analyses using net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (NRI 0.58 [0.07-1.02], p < 0.01; and IDI 0.030 [0.001-0.085], p = 0.02). CONCLUSION: High plasma levels of SDF-1α were associated with the short-term decline of eGFR in patients with CAD. Thus, SDF-1α may be useful for predicting the progression of renal dysfunction in patients with CAD.

Pulmonary Vascular Resistance Is Associated With Brachial-Ankle Pulse-Wave Velocity and Adverse Clinical Outcomes in Patients With Heart Failure With Preserved Ejection Fraction.

BACKGROUND: The precise mechanisms underlying the high prevalence of pulmonary hypertension (PH) with increased pulmonary vascular resistance (PVR) in heart failure with preserved ejection fraction (HFpEF) remain largely unknown. Measurements of brachial-ankle pulse wave velocity (baPWV) have been shown to be useful for risk assessment in HF patients. Thus, this study sought to define the association of PVR with baPWV and clinical outcomes in HFpEF. METHODS AND RESULTS: Patients with HFpEF (n = 198) had measurements of baPWV and PVR by right heart catheterization, and were prospectively followed-up for <96 months or until the occurrence of a composite of all-cause death, hospitalization with worsening HF, and nonfatal acute coronary syndrome. RESULTS: Multivariate logistic analysis showed that baPWV was independently associated with PH with increased PVR (P < .001). During the follow-up period, 46 clinical events occurred. Multivariate Cox proportional hazards analysis showed that PH with increased PVR was a significant predictor of adverse outcomes after adjustment for conventional risk factors (HR 1.96, 95% CI 1.03-3.76, P = .04). CONCLUSIONS: PH with increased PVR was associated with increased baPWV and adverse clinical outcomes in HFpEF. Thus, increased arterial stiffness may contribute to increased risk predictability of PVR for patients with HFpEF.

Human soluble phospholipase A2 receptor is an inhibitor of the integrin-mediated cell migratory response to collagen-I.

Murine membrane-bound phospholipase A2 receptor 1 (PLA2R) is shed and released into plasma in a soluble form that retains all of the extracellular domains. Relatively little is known about human PLA2R. This study examined whether human soluble PLA2R has biological functions and whether soluble PLA2R exists in human plasma. Here, we showed that human recombinant soluble PLA2R (rsPLA2R) bound to collagen-I and inhibited interaction of collagen-I with the extracellular domain of integrin ß1 on the cell surface of human embryonic kidney 293 (HEK293) cells. As a result, rsPLA2R suppressed integrin ß1-mediated migratory responses of HEK293 cells to collagen-I in Boyden chamber experiments. Inhibition of phosphorylation of FAK Tyr397 was also observed. Similar results were obtained with experiments using soluble PLA2R released from HEK293 cells transfected with a construct encoding human soluble PLA2R. rsPLA2R lacking the fibronectin-like type II (FNII) domain had no inhibitory effects on cell responses to collagen-I, suggesting an important role of the FNII domain in the interaction of rsPLA2R with collagen-I. In addition, rsPLA2R suppressed the migratory response to collagen-IV and binding of collagen-IV to the cell surface of human podocytes that endogenously express membrane-bound, full-length PLA2R. Immunoprecipitation and Western blotting showed the existence of immunoreactive PLA2R in human plasma. In conclusion, human recombinant soluble PLA2R inhibits integrin ß1-mediated cell responses to collagens. Further studies are warranted to elucidate whether immunoreactive PLA2R in human plasma has the same properties as rsPLA2R.

Effect of coronary artery spasm on long-term outcomes in survivors of acute myocardial infarction.

BACKGROUND: The prevalence of coronary artery spasm (CAS) inducible by intracoronary injection of acetylcholine (ACh) is high in survivors of acute myocardial infarction (AMI). Although there is a potential risk of sudden cardiac death in patients with CAS, the prognostic value of CAS was not clear. Thus, this study examined the effect of CAS on long-term prognosis in survivors of AMI in a prospective manner. METHODS: The study included a total of 437 patients with AMI who underwent a CAS provocation test using ACh. All patients were followed prospectively for 5years or until the occurrence of the primary composite endpoint that consisted of cardiac death and acute coronary syndrome (ACS). RESULTS: CAS was induced in 195 (45%) of the study patients. During the follow-up period, 30 patients had a recurrent event (4 had cardiac death and 26 had ACS). Kaplan-Meier estimates in time-to-first-event analysis demonstrated a similar probability of the primary endpoint in patients with and without inducible CAS (p=0.13, log-rank test). The rate of each component of the composite endpoint was also comparable between the 2 patient groups. In Cox proportional hazards risk analysis, treatment with calcium channel blockers (CCBs) negatively predicted the primary endpoints in patients with inducible CAS (HR, 0.21; 95% CI, 0.08-0.55, p<0.01). CONCLUSIONS: The presence of inducible CAS did not increase the incidence of the cardiac events in AMI survivors. Treatment with CCBs may improve outcomes in AMI survivors with inducible CAS. CLINICAL TRIAL REGISTRATION: URL: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000021340, unique identifier: UMIN000018432.

Angiotensin II receptor blockers suppress the release of stromal cell-derived factor-1α from infarcted myocardium in patients with acute myocardial infarction.

BACKGROUND: Although angiotensin II receptor blockers (ARBs) have been shown to have anti-inflammatory effects on infarcted myocardium in experimental models, little is known in humans. Stromal cell-derived factor-1α (SDF-1α), a pro-inflammatory chemokine, is released from infarcted tissue in patients with acute myocardial infarction (AMI). This study examined whether ARBs suppress SDF-1α production in the infarcted lesion in patients with AMI. METHODS: SDF-1α levels were measured by enzyme-linked immunosorbent assays in plasma obtained from the aortic root (AO) and the anterior interventricular vein (AIV) in 50 patients with an anterior AMI. Measurement of SDF-1α levels and left ventriculography were repeated at discharge and 6 months after AMI. Patients were divided into 2 groups according to treatment with ARBs, which were administered at the discretion of the attending physician after admission. RESULTS: The AIV-AO gradient of SDF-1α, reflecting SDF-1α release from the infarcted myocardial region, decreased between the time of discharge and 6 months after AMI in patients taking an ARB. In contrast, the SDF-1α transcardiac gradient did not change in patients not taking an ARB. Among the clinical parameters tested, only the use of ARBs was significantly associated with percent changes in the SDF-1α transcardiac gradient from the time of discharge to 6 months after AMI in a linear regression analysis (r=-0.31, p=0.03). The SDF-1α transcardiac gradient 6 months after AMI was inversely correlated with the percent change in left ventricular (LV) ejection fraction (r=-0.52, p<0.01) and positively correlated with the percent change in LV end-diastolic volume index (r=0.57, p<0.01) and LV end-systolic volume index (r=0.54, p<0.01) during 6 months after AMI. CONCLUSIONS: ARB treatment suppressed SDF-1α release from the infarcted myocardial region, which was associated with improvement in LV dysfunction and adverse remodeling in AMI survivors.

Echolucency of the carotid artery is associated with short-term plaque progression and positive remodeling in the culprit coronary artery in AMI survivors.

BACKGROUND: Rapid plaque progression and positive remodeling are recognized as vulnerable coronary plaque characteristics. This study examined whether serial carotid ultrasonography might be of value for assessment of coronary plaque progression and positive remodeling, measured by serial intravascular ultrasound (IVUS), in survivors of acute myocardial infarction (AMI). METHODS: Thirty-nine patients with AMI had repeated examinations by IVUS of culprit coronary arteries and echolucency of the coronary artery on admission (1st test) and 6 months later (2nd test). Plaque volume and external elastic membrane area of the native segment (15±9mm in length) beginning 5mm proximal to the stent edge in the culprit coronary artery were measured using volumetric IVUS. Echolucency of the carotid artery was assessed by integrated backscatter (IBS) analysis. Lower IBS reflects an echolucent and lipid-rich plaque. RESULTS: Increase in coronary plaque volume and positive remodeling over 6 months occurred in 17 and 12 patients, respectively. The % change in carotid IBS value over 6 months was correlated with the % change in the coronary plaque volume (r=-0.69, p<0.001). The aggravated change in the carotid IBS was significantly associated with increase in the coronary plaque volume and positive remodeling over 6 months (OR 0.94 and 0.95, respectively, 95% CI 0.90-0.99, both p<0.05). CONCLUSIONS: Serial measurements of echolucency of the carotid artery may be of value for assessment of short-term progression and positive remodeling of coronary plaques in AMI survivors.

Remnant lipoproteinemia predicts cardiovascular events in patients with type 2 diabetes and chronic kidney disease.

BACKGROUND: Patients having type 2 diabetes mellitus (DM) and chronic kidney disease (CKD) are at high risk of cardiovascular events. Triglyceride-rich lipoprotein levels are synergistically increased in patients with DM and CKD. This study examined the predictive value of remnant lipoprotein levels for cardiovascular events in patients with DM and CKD. METHODS: Three hundred and sixty-five patients with type 2 DM and CKD were enrolled. Serum levels of remnant lipoproteins (remnant-like lipoprotein particles cholesterol; RLP-C) were measured by an immunoseparation method. All patients were followed prospectively for a period of 45±23 months or until occurrence of one of the following events: cardiac death, non-fatal myocardial infarction, unstable angina requiring unplanned coronary revascularization, or ischemic stroke. RESULTS: During the follow-up period, 59 patients had cardiovascular events. Multivariate Cox analysis revealed that high levels of RLP-C (≥4.3mg/dL; median value) were a significant risk factor for cardiovascular events, independent of traditional risk factors (HR: 1.30; 95% CI: 1.04-1.63; p=0.02). The addition of high levels of RLP-C to traditional risk factors improved net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (NRI 0.36, p=0.01; and IDI 0.03, p=0.02). CONCLUSIONS: RLP-C is useful for risk assessment of future cardiovascular events in patients having type 2 DM and CKD.

High levels of stromal cell-derived factor-1α predict secondary cardiac events in stable patients with a history of myocardial infarction.

BACKGROUND: We recently showed that stromal cell-derived factor (SDF)-1α, a pro-inflammatory mediator, is produced in infarcted myocardium and is associated with left ventricular (LV) adverse remodeling and progressive dysfunction following acute myocardial infarction (AMI). The current study examined whether SDF-1α levels in the peripheral vein can provide prognostic information of outcomes in stable patients with a history of MI. METHODS: Plasma levels of SDF-1α in the peripheral vein were measured by enzyme-linked immunosorbent assay in 192 stable patients with a history of MI. All patients were followed prospectively for a period of 90 months or until occurrence of one of the following cardiac events: cardiac death, non-fatal myocardial infarction, unstable angina requiring unplanned coronary revascularization, or worsening heart failure requiring hospital admission. RESULTS: During the follow-up period (77±26 months), 30 patients had cardiac events. Multivariate Cox analysis revealed that high levels of SDF-1α (≥2162pg/mL; a cut-off value determined by receiver-operating characteristic analysis) were a significant predictor of cardiac events, independent of traditional risk factors (HR: 1.98; 95% CI: 1.38-2.85; p<0.001). The addition of high levels of SDF-1α to conventional risk factors including brain natriuretic peptide improved net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (NRI 0.90, p<0.0001; and IDI 0.05, p=0.002). CONCLUSIONS: High levels of SDF-1α predicted secondary cardiac events in stable patients with a history of MI. SDF-1α levels may be a useful risk assessment tool in patients with a history of MI.

Phospholipase A2 Receptor Gene Polymorphisms Alter its Functions and Present a Genetic Risk of an Increased Intima-Media Thickness of the Carotid Artery.

AIMS: Phospholipase A2 receptor 1 (PLA2R) has multiple biological functions other than functioning as a receptor for secretory PLA2s. Two nonsynonymous polymorphisms in the C-type lectin-like domains (CTLD) 1 of PLA2R gene have been associated with idiopathic membranous nephropathy. This study examined whether the same PLA2R polymorphisms may alter functions of PLA2R in cells expressing the variant PLA2R. In addition, the clinical relevance of the experiment was examined. METHODS: Two nonsynonymous polymorphisms (T/C at rs3749117 and G/C at rs35771982) in CTLD1 of PLA2R gene were completely linked. HEK293 cells expressing human wild-type PLA2R (T at rs3749117 and G at rs35771982) or human mutant PLA2R that had double mutations (C at rs3749117 and C at rs35771982) were constructed. RESULTS: HEK293 cells expressing mutant PLA2R had lower migratory and proliferative responses to collagen I compared with cells expressing wild-type PLA2R. In 580 male patients, PLA2R gene polymorphisms were associated with an increase in maximum intima-media thickness (maxIMT) of the carotid artery. The multivariate regression model showed that PLA2R gene polymorphisms were a risk factor of an increased maxIMT that was independent of conventional risk factors (OR=1.93, 95% CI: 1.17-3.19, p＜0.01). CONCLUSIONS: The nonsynonymous common variants of PLA2R gene altered biological functions in cells expressing variant PLA2R. PLA2R gene polymorphisms present a genetic risk of an increased IMT of the carotid artery in male. The functional changes in the variant PLA2R may potentially be responsible for its association with an increased IMT of the carotid artery.

Myocardial Production of Plasminogen Activator Inhibitor-1 is Associated with Coronary Endothelial and Ventricular Dysfunction after Acute Myocardial Infarction.

AIM: Although plasminogen activator inhibitor-1 (PAI-1) is abundantly expressed in infarcted myocardium, the pathogenic role of myocardial PAI-1 remains unknown. This study examined whether PAI-1 in the infarcted lesion contributes to coronary endothelial dysfunction and left ventricular (LV) dysfunction in patients with acute myocardial infarction (AMI). METHODS: Plasma levels of PAI-1 activity and tissue-plasminogen activator (tPA) antigen were measured 2 weeks and 6 months after MI by ELISA in plasma obtained from the aortic root (AO) and anterior interventricular vein (AIV) in 28 patients with a first AMI due to occlusion of the left anterior descending coronary artery (LAD). Coronary blood flow responses in LAD to intracoronary infusion of acetylcholine (ACh) and left ventriculography were measured at the same time points: 2 weeks and 6 months after MI. RESULTS: The trans-myocardial gradient of PAI-1 from AO to AIV, reflecting production/release of PAI-1 in the infarcted lesion, was inversely correlated with the coronary blood flow response to ACh 6 months after MI (r=-0.43, p=0.02) and with the percentage change in LV regional motion in the LAD territory from 2 weeks to 6 months after MI (r=-0.38, p=0.04). The trans-myocardial gradient of tPA level showed no significant correlations. CONCLUSIONS: PAI-1 produced in the infarcted myocardium and released into the coronary circulation is associated with endothelial dysfunction in resistance vessels of the infarct-related coronary arteries and with progressive dysfunction of the infarcted region of the left ventricle in AMI survivors.

Sustained myocardial production of stromal cell-derived factor-1α was associated with left ventricular adverse remodeling in patients with myocardial infarction.

The role of stromal cell-derived factor-1α (SDF-1α) expressed in infarcted myocardium is unknown in humans. We examined whether SDF-1α produced in an infarcted myocardial lesion may play a role in left ventricle (LV) remodeling and dysfunction in patients with acute myocardial infarction (AMI). We measured SDF-1α levels in plasma obtained from aortic root (AO) and anterior interventricular vein (AIV) in the early phase (2 wk after MI) and the chronic phase (6 mo after MI) in 80 patients with anterior MI. An increment in SDF-1α level from AO to AIV, reflecting SDF-1α release from infarcted myocardium, was more frequent in patients with MI in the early phase of MI [n = 52 (65%), P = 0.03] but not in the chronic phase of MI [n = 46 (58%), P = 0.11] compared with that in control patients [n = 6/17 (35%)]. On linear regression analysis, the transmyocardial gradient in SDF-1α level in the chronic phase of MI was correlated with percentage changes in LV end-diastolic volume index (r = 0.39, P < 0.001), LV end-systolic volume index (r = 0.38, P < 0.001), and LV ejection fraction (r = -0.26, P = 0.01) 6 mo after AMI. By contrast, the transmyocardial gradient of SDF-1α in the early phase of MI had no significant correlations. In conclusion, the production of SDF-1α in infarcted myocardium in the chronic phase of MI was associated with LV adverse remodeling and progressive dysfunction in AMI survivors.

Assessment of carotid plaque neovascularization using quantitative analysis of contrast-enhanced ultrasound imaging is useful for risk stratification in patients with coronary artery disease.

BACKGROUND: Contrast-enhanced ultrasound (CEUS) of the carotid artery is a potential technique for imaging plaque neovascularization, a feature of unstable atherosclerotic plaques. This study examined whether assessment of intra-plaque neovascularization of the carotid artery using CEUS provides prognostic information in patients with coronary artery disease (CAD). METHODS: A total of 206 patients with stable CAD underwent a CEUS examination of the carotid artery and were followed up prospectively for <38 months or until a cardiac event (cardiac death, non-fatal myocardial infarction (MI), unstable angina pectoris (uAP) requiring unplanned coronary revascularization, or heart failure requiring hospitalization). The degree of contrast signals measured within the carotid plaque was quantified by calculating the mean gray scale level within the region of interest of the carotid plaque, expressed as plaque enhanced intensity. RESULTS: During the follow-up period, 31 events occurred (2 cardiac deaths, 7 non-fatal MIs, 16 uAP, and 6 heart failure). Multivariate Cox proportional hazard analysis showed that plaque enhanced intensity was a significant predictor of cardiac events independent of traditional risk factors (HR, 1.13; 95% CI, 1.05-1.21; p<0.001). The addition of the plaque enhanced intensity to traditional risk factors resulted in net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (NRI 0.62, p=0.001; and IDI 0.106, p=0.002). CONCLUSIONS: The assessment of carotid plaque neovascularization using quantitative analysis of CEUS may be useful for risk stratification in patients with CAD.