Reciprocal regulation of endothelial-mesenchymal transition by MAPK7 and EZH2 in intimal hyperplasia and coronary artery disease.

Endothelial-mesenchymal transition (EndMT) is a form of endothelial dysfunction wherein endothelial cells acquire a mesenchymal phenotype and lose endothelial functions, which contributes to the pathogenesis of intimal hyperplasia and atherosclerosis. The mitogen activated protein kinase 7 (MAPK7) inhibits EndMT and decreases the expression of the histone methyltransferase Enhancer-of-Zeste homologue 2 (EZH2), thereby maintaining endothelial quiescence. EZH2 is the catalytic subunit of the Polycomb Repressive Complex 2 that methylates lysine 27 on histone 3 (H3K27me3). It is elusive how the crosstalk between MAPK7 and EZH2 is regulated in the endothelium and if the balance between MAPK7 and EZH2 is disturbed in vascular disease. In human coronary artery disease, we assessed the expression levels of MAPK7 and EZH2 and found that with increasing intima/media thickness ratio, MAPK7 expression decreased, whereas EZH2 expression increased. In vitro, MAPK7 activation decreased EZH2 expression, whereas endothelial cells deficient of EZH2 had increased MAPK7 activity. MAPK7 activation results in increased expression of microRNA (miR)-101, a repressor of EZH2. This loss of EZH2 in turn results in the increased expression of the miR-200 family, culminating in decreased expression of the dual-specificity phosphatases 1 and 6 who may repress MAPK7 activity. Transfection of endothelial cells with miR-200 family members decreased the endothelial sensitivity to TGFß1-induced EndMT. In endothelial cells there is reciprocity between MAPK7 signaling and EZH2 expression and disturbances in this reciprocal signaling associate with the induction of EndMT and severity of human coronary artery disease.

Poly(ADP-Ribose) Polymerase Activity and Coronary Artery Disease in Type 2 Diabetes Mellitus: An Observational and Bidirectional Mendelian Randomization Study.

OBJECTIVE: Experimental evidence suggests a close link between PARP (poly[ADP-ribose] polymerase) activation and diabetic endothelial dysfunction. Here, we tested whether PARP activity in circulating leukocytes was associated with coronary artery disease (CAD) among patients with type 2 diabetes mellitus (T2DM). Approach and Results: We performed observational and bidirectional Mendelian randomization studies of 3149 Chinese individuals with T2DM who underwent coronary angiography, with leukocyte PARP activity, 16 tag single-nucleotide polymorphisms in PARP1 and PARP2, and 17 CAD risk single-nucleotide polymorphisms analyzed. Of 3149 participants, 1180 who further received percutaneous coronary intervention were prospectively followed for 1 year to track major adverse cardiovascular and cerebrovascular events. Overall, greater PARP activity was cross-sectionally associated with an odds ratio of 1.23 for obstructive CAD, and prospectively with a hazard ratio of 1.34 for 1-year major adverse cardiovascular and cerebrovascular events after percutaneous coronary intervention (both P<0.001). Using a genetic score of 5 screened single-nucleotide polymorphisms in PARP1 and PARP2 as the instrumental variable, genetically predicted elevation in PARP activity showed a causal association with obstructive CAD (odds ratio=1.35, P<0.001). In contrast, the genetic risk of CAD had no significant effect on PARP activity. Ex vivo and in vitro cultures of human monocytes showed that rs747657, as the lead single-nucleotide polymorphism strongly associated with PARP activity, caused the differential binding of transcription factor GATA2 (GATA-binding protein 2) to an intronic regulatory region in PARP1, thus modulating PARP1 expression and PARP activity. CONCLUSIONS: Greater PARP activity may have causal roles in the development of obstructive CAD among patients with diabetes mellitus.

The relationship of lipoprotein-associated phospholipase A2 activity with the seriousness of coronary artery disease.

BACKGROUND: The level of lipoprotein-associated phospholipase A2 (LP-PLA2) in serum is independently correlated to coronary artery diseases (CAD). The aim of the study was to determine whether LP-PLA2 activity is positively associated with the seriousness of CAD. METHODS: Amount to 1056 patients suspected of having CAD underwent coronary angiography (CAG) to determine the seriousness of CAD. According to the amount of diseased coronary branches, the 1056 patients were split into three groups: single-vessel stenosis group, multiple-vessels stenosis group (> or = 2 diseased coronary branches),and control group (no diseased coronary branches). According to CAG results, electrocardiography, cardiac biomarker, and clinical presentation, all patients were split into four groups: acute myocardial infarction (AMI), unstable angina (UA), stable angina (SA), and control groups (excluding CAD). The activity of LP-PLA2 was compared statistically among the subgroups. Receiver operating characteristic analysis was applied to investigate the role of LP-PLA2 in evaluating the presence and seriousness of CAD. RESULTS: The level of LP-PLA2 increased in line with the number of diseased coronary branches. The levels of LP-PLA2 in the AMI and UA groups were observably higher when compared with the control and SA groups. LP-PLA2 had 75.6% sensitivity and 67.3% specificity for recognizing CAD, and 53.0% sensitivity and 80.3% specificity for recognizing severe coronary artery lesions. CONCLUSION: The activity of LP-PLA2 is positively correlated to the seriousness of CAD.

Serum level of gamma-glutamyl transferase as a biomarker for predicting stenosis severity in patients with coronary artery disease.

BACKGROUND: Gamma glutamyl transferase (GGT) is associated with pathogenesis of various diseases such as coronary artery disease (CAD). GGT activity displays an essential role in the catabolism of glutathione which is reported as a major antioxidant. The aim of this study was to explore the association of GGT activity with obstruction severity of artery in 500 CAD patients. RESULTS: Our finding showed a significant association between serum GGT activity and CAD patients. In particular, the level of GGT in patients who had ≥50% obstruction was higher, compared to healthy and patients with less than 50% obstruction in their coronary arteries (the level of GGT in patients with at least one (1 SVD), two (2VD), three (3VD) coronary artery obstruction were 55.6±9.7, 71.7±12.7 and 84.7±13.4, while these values in patients with negative angio or control group were 28±10 and 17±4.6). Furthermore, the activity of this marker was associated with increased the risk of CAD (Odd ratio of GGT in 3VD group: 2, 95%CI: 1.8-2.3), which was also related with HDL-C. Of note, the level of GGT was enhanced progressively with increasing the obstruction severity of arteries. CONCLUSION: We demonstrate the prognostic value of serum level of GGT as a biomarker for predicting obstruction severity in patients with CAD.

Ossabaw Pigs With a PCSK9 Gain-of-Function Mutation Develop Accelerated Coronary Atherosclerotic Lesions: A Novel Model for Preclinical Studies.

BACKGROUND: Ossabaw pigs are unique miniature swine with genetic predisposition to develop metabolic syndrome and coronary atherosclerosis after extended periods receiving atherogenic diets. We have hypothesized that transgenic Ossabaw swine expressing chimp PCSK9 (proprotein convertase subtilisin-like/kexin type 9) containing the D374Y gain of function would develop familial hypercholesterolemia and coronary artery plaques more rapidly than Landrace swine with the same transgene. METHODS AND RESULTS: Ossabaw and Landrace PCSK9 gain-of-function founders were generated by Sleeping Beauty transposition and cloning. Histopathologic findings in the Ossabaw founder animal showed more advanced plaques and higher stenosis than in the Landrace founder, underscoring the Ossabaw genetic predisposition to atherosclerosis. We chose to further characterize the Ossabaw PCSK9 gain-of-function animals receiving standard or atherogenic diets in a 6-month longitudinal study using computed tomography, magnetic resonance (MR) imaging, intravascular ultrasound, and optical coherence tomography, followed by pathological analysis of atherosclerosis focused on the coronary arteries. The Ossabaw model was consistently hypercholesterolemic, with or without dietary challenge, and by 6 months had consistent and diffuse fibrofatty or fibroatheromatous plaques with necrosis, overlying fibrous caps, and calcification in up to 10% of coronary plaques. CONCLUSIONS: The Ossabaw PCSK9 gain-of-function model provides consistent and robust disease development in a time frame that is practical for use in preclinical therapeutic evaluation to drive innovation. Although no animal model perfectly mimics the human condition, this genetic large-animal model is a novel tool for testing therapeutic interventions in the context of developing and advanced coronary artery disease.

VEGF attenuates 2-VO induced cognitive impairment and neuronal injury associated with the activation of PI3K/Akt and Notch1 pathway.

Vascular endothelial growth factor (VEGF) has been identified as a potential treatment for effectively improving cognitive function in several neuropathological conditions. However, the underlying mechanism and the relevant downstream protective pathways that are activated in neurons by VEGF remain elusive, especially in chronic global cerebral ischemia. In this study, we intended to investigate the signaling mechanisms of VEGF in cognitive protection and anti-apoptosis in a rat model of chronic global cerebral ischemia induced by permanent bilateral common carotid artery occlusion (2-VO). The results showed that intranasal administration of VEGF (72h post-ischemia for 6 successive days) caused a significant improvement in the cognitive deficits induced by 2-VO, accompanied by a reversal of oxidative stress and VEGF depletion in the hippocampus. In addition, VEGF-treatment decreased the expression of Bax and Caspase-3, increased the expression of anti-apoptotic Bcl-xl and the main protein involved in energy homeostasis AMP-activated protein kinase (AMPK), which may account for the anti-apoptotic effects of VEGF. Importantly, VEGF administration upregulated the phosphorylation levels of Akt (pAkt) and PI3K, activated Notch1 pathway in 2-VO hippocampus. These findings suggested that intranasal administration of VEGF alleviated cognitive impairment induced by 2-VO injury, and attenuated oxidative damage and neuronal injury in hippocampus associated with the regulation of PI3K/Akt and Notch1 signaling pathway, which might be the underlying mechanisms of VEGF on global chronic cerebral ischemia.

Matrix metalloproteinase-3 gene polymorphism (rs3025058) affects markers atherosclerosis in type 2 diabetes mellitus.

BACKGROUND: The study was designed to test the possible association between either polymorphisms of the matrix metalloproteinase-9 (MMP-9) gene (rs17576, rs3918242) or the MMP-3 5A/6A gene polymorphism (rs3025058) with markers of carotid atherosclerosis in patients with type 2 diabetes mellitus (T2DM). The second aim of the study was to demonstrate an association between either the rs17576, rs3918242 or rs3025058 and subclinical markers of coronary artery disease in the same subset of patients with T2DM. PATIENTS AND METHODS: A total of 595 subjects with T2DM and 200 subjects without T2DM (control group) were enrolled in the prospective study. Subclinical markers of carotid atherosclerosis were assessed ultrasonographically. Additionally, in a subset of subjects with T2DM a coronary computed tomography angiography (CCTA) was performed for diagnostic purposes. Genotyping of all three polymorphisms (rs17576, rs3918242, rs3025058) was performed with real-time PCR systems. RESULTS: The comparison of atherosclerosis parameters was performed with regard to different genotypes of MMP-9 rs17576, rs3918242, and MMP-3 rs3025058 polymorphisms upon enrolment and during follow-up. In our study, we found an association between the MMP-3 rs3025058 and CIMT at the time of recruitment. Multiple linear regression analysis revealed the association of either the A- allele or the A- genotypes of the rs3025058 (MMP-3) with carotid intima media thickness (CIMT) progression in a 3.8-year follow-up. We demonstrated the effect of the rs3025058 on subclinical markers of coronary atherosclerosis (coronary calcium score, number of coronary arteries with more than 50 % stenosis, and presence of at least one vessel with more than 50 % stenosis). CONCLUSIONS: We found an association between the MMP-3 rs3025058 and subclinical markers of carotid (CIMT) and coronary atherosclerosis at the time of recruitment. Moreover, we demonstrated the effect of the MMP-3 rs3025058 on CIMT progression in the 3.8-year follow-up in patients with T2DM.

Correlation between genetic polymorphisms within the MAPK1/HIF-1/HO-1 signaling pathway and risk or prognosis of perimenopausal coronary artery disease.

BACKGROUND: Mitogen-activated protein kinase-1 (MAPK1), as well as its downstream factors of hypoxia-inducible factor-1 (HIF-1) and heme oxygenase-1 (HO-1), have been documented to be involved in modulating development of coronary artery disease (CAD). HYPOTHESIS: Genetic mutations within the MAPK1/HIF-1/HO-1 signaling pathway could alter the risk of perimenopausal CAD in Chinese patients. METHODS: Peripheral blood samples were gathered from 589 CAD patients and 860 healthy controls, and 12 potential single-nucleotide polymorphisms (SNPs) were obtained from HapMap database and previously published studies. Genotyping of SNPs was implemented with the TaqMan SNP Genotyping Assays. Odds ratios (OR) and 95% confidence intervals (CI) were utilized to evaluate the correlations between SNPs and CAD risk. RESULTS: Regarding MAPK1 , rs6928 (OR: 1.71, 95% CI: 1.47-1.98, P < 0.05), rs9340 (OR: 0.85, 95% CI: 0.73-0.99, P < 0.05), and rs11913721 (OR: 0.70, 95% CI: 0.52-0.95, P < 0.05) were remarkably associated with susceptibility to perimenopausal CAD. Of these, rs9340 and rs11913721 were also regarded as protective factors for perimenopausal CAD patients. Moreover, results of HIF-1 indicated noticeable correlations between combined SNPs of rs1087314 and rs2057482 and risk of perimenopausal CAD (OR: 1.24, 95% CI: 1.01-1.53, P < 0.05; and OR: 0.71, 95% CI: 0.55-0.91, P < 0.05, respectively). Nonetheless, rs2071746 in HO-1 was found to be only associated with perimenopausal CAD risk (OR: 0.67, 95% CI: 0.58-0.78, P < 0.05). CONCLUSIONS: The genetic mutations within MAPK1 (rs6928, rs9340, rs11913721), HIF-1 (rs1087314, rs2057482), and HO-1 (rs2071746) could alter susceptibility to perimenopausal CAD in this Chinese population.

NQO1 C609T Polymorphism is Associated with Coronary Artery Disease in a Gender-Dependent Manner.

Findings on the association of NQO1 C609T polymorphism in the NQO1 gene and cardiovascular disease susceptibility are controversial. The objective of the current study was to examine the relationship between this polymorphism and the presence and severity of angiographically determined coronary artery disease (CAD). One-hundred and forty-five patients with newly diagnosed angiographically documented CAD (≥50 % luminal stenosis of any coronary vessel) as case group were compared to 139 controls (subjects with no luminal stenosis at coronary arteries). The presence of C609T polymorphism was analyzed using polymerase chain reaction-based restriction fragment length polymorphism. Among total population, those with combined CT/TT (T allele carrier) genotype showed a trend toward lower odds of CAD compared to those with CC (wild type) genotype, but it did not reach a statistically significant level (p = 0.061). When data were analyzed separately for men or women, CT + TT group as compared to CC genotype was associated with decreased odds of CAD in women (adjusted OR 0.4, 95 % CI 0.2-0.9; p = 0.043), but not in men (adjusted OR 0.8, 95 % CI 0.3-1.9; p = 0.612). The C609T polymorphism within NQO1 is independently associated with CAD in women, but no association was observed in whole study population or in men.

Local Matrix Metalloproteinase 9 Level Determines Early Clinical Presentation of ST-Segment-Elevation Myocardial Infarction.

OBJECTIVE: Early clinical presentation of ST-segment-elevation myocardial infarction (STEMI) and non-ST-segment-elevation myocardial infarction affects patient management. Although local inflammatory activities are involved in the onset of MI, little is known about their impact on early clinical presentation. This study aimed to investigate whether local inflammatory activities affect early clinical presentation. APPROACH AND RESULTS: This study comprised 94 and 17 patients with MI (STEMI, 69; non-STEMI, 25) and stable angina pectoris, respectively. We simultaneously investigated the culprit lesion morphologies using optical coherence tomography and inflammatory activities assessed by shedding matrix metalloproteinase 9 (MMP-9) and myeloperoxidase into the coronary circulation before and after stenting. Prevalence of plaque rupture, thin-cap fibroatheroma, and lipid arc or macrophage count was higher in patients with STEMI and non-STEMI than in those with stable angina pectoris. Red thrombus was frequently observed in STEMI compared with others. Local MMP-9 levels were significantly higher than systemic levels (systemic, 42.0 [27.9-73.2] ng/mL versus prestent local, 69.1 [32.2-152.3] ng/mL versus poststent local, 68.0 [35.6-133.3] ng/mL; P<0.01). Poststent local MMP-9 level was significantly elevated in patients with STEMI (STEMI, 109.9 [54.5-197.8] ng/mL versus non-STEMI: 52.9 [33.0-79.5] ng/mL; stable angina pectoris, 28.3 [14.2-40.0] ng/mL; P<0.01), whereas no difference was observed in the myeloperoxidase level. Poststent local MMP-9 and the presence of red thrombus are the independent determinants for STEMI in multivariate analysis. CONCLUSIONS: Local MMP-9 level could determine the early clinical presentation in patients with MI. Local inflammatory activity for atherosclerosis needs increased attention.

Usefulness of Neuron-Specific Enolase to Detect Silent Neuronal Ischemia After Percutaneous Coronary Intervention.

Increased plasma levels of neuron-specific enolase (NSE) are related to damage of neurons and neuroendocrine cells. We aimed to investigate elevation of NSE after elective percutaneous coronary intervention (PCI) on the prediction of silent cerebral infarct (SCI). Study population consisted of 2 groups of patients. Group 1 included 92 consecutive patients with normal coronary angiograms, whereas group 2 consisted of 89 patients who underwent elective coronary stenting. NSE levels were studied before and 12 hours after the procedure. Elevation of >0.12 µg/L was considered as SCI. Forty-seven of 181 study patients (26%) had SCI after the procedure. NSE elevation was significantly more prevalent in patients with PCI than that of controls. Elevation of NSE was observed in 42% of patients who underwent elective PCI (n = 37) and 11% of the normal coronary artery group (n = 10) (p <0.001). The incidence of SCI was higher in active smokers and patients who had history of myocardial infarction (MI) (55% vs 10%, p <0.001 for active smokers and 40% vs 8%, p <0.001 for history of MI, respectively). Multivariate analysis demonstrated history of smoking (odds ratio [OR] 9.9; 95% confidence interval [CI] 3.7 to 26.9; p <0.001) and previous MI (OR 4.4; 95% CI 1.7 to 11.4; p = 0.01) as independent predictors of SCI. For patients who underwent elective PCI, NSE levels after procedure increases. Invasive coronary procedures have risk of SCIs, even in patients with normal coronary arteries. In conclusion, increased diagnosis of SCIs might improve understanding of their relation with invasive cardiac procedures, facilitate to prevent occurrence of silent microemboli and decrease the risk of adverse neurologic events.

Case control feasibility study assessing the association between severity of coronary artery disease with Glutathione Peroxidase-1 (GPX-1) and GPX-1 polymorphism (Pro198Leu).

BACKGROUND: Glutathione peroxidase-1 (GPX-1) activity was reported to be useful marker for monitoring cardiovascular disease. However, accurate assessment of coronary artery disease (CAD) using GPX-1 polymorphism is limited for South Asian population. Present study aim to assess GPX-1activity and GPX-1 polymorphismin patients with coronary artery disease (CAD) who were confirmed with coronary angiography findings and in apparently healthy subjects. METHODS: Case control study was carried out with 85 patients (58 males and 27 females) 40-60 years of age confirmed as having CAD on coronary angiography findings and 85 age and sex matched healthy volunteers as controls. Blood samples were analyzed for erythrocyte GPX-1 activity and GPX-1 polymorphism in both groups and the severity of CAD was assessed using coronary angiography scoring system based on vessel, stenosis and extent score. RESULTS: Coronary angiography scores indicated that erythrocyteGPX-1 cutoff value of 23.9 U/gHb showed a high sensitivity and negative predictive value in ruling out major vessel disease. The GPX-1 Pro198Leu (CT) polymorphism was higher in patients with CAD (25.3 %) when compared to controls (10.7 %). Pro198Leu (CT) genotype showed a 2.84 fold risk for CAD [odds ratio 2.84 (95 % CI 1.15-6.98), p = 0.019]. CONCLUSION: Coronary angiography findings indicated that individuals possessing Pro198Leu (CT) polymorphism were found to be associated with low erythrocyte GPX-1 activity and increased susceptibility for CAD.

Beneficial effects of omega-3 and vitamin E coadministration on gene expression of SIRT1 and PGC1α and serum antioxidant enzymes in patients with coronary artery disease.

BACKGROUND AND AIM: SIRT1 and PGC1α are two important genes, which play critical roles in regulating oxidative stress and inflammation processes. The study aimed assess the effects of coadministration of omega-3 and vitamin E supplements on SIRT1 and PGC1α gene expression and serum levels of antioxidant enzymes in coronary artery disease (CAD) patients. METHODS AND RESULTS: Participants of this randomized controlled trial included 60 CAD male patients who were categorized into three groups: Group 1 received omega-3 (4 g/day) and vitamin E placebo (OP), group 2 omega-3 (4 g/day) and vitamin E (400 IU/day; OE), and group 3 omega-3 and vitamin E placebos (PP) for 2 months. Gene expression of SIRT1 and PGC1α in peripheral blood mononuclear cells (PBMCS) was assessed by reverse transcription polymerase chain reaction (RT-PCR). Furthermore, serum antioxidant enzyme and high-sensitivity C-reactive protein (hsCRP) levels were assessed at the beginning and end of the intervention. Gene expression of SIRT1 and PGC1α increased significantly in the OE group (P = 0.039 and P = 0.050, respectively). Catalase and hsCRP levels increased significantly in the OE and OP groups. However, glutathione peroxidase (GPX) and superoxide dismutase (SOD) levels did not statistically change in all groups. The total antioxidant capacity (TAC) increased significantly in the OE group (P = 0.009) but not in OP and PP groups. CONCLUSION: Supplementation of omega-3 fatty acids in combination with vitamin E may have beneficial effects on CAD patients by increasing gene expression of SIRT1 and PGC1α and improving oxidative stress and inflammation in these patients.

Endoplasmic Reticulum Is Involved in Myocardial Injury in a Miniature Swine Model of Coronary Artery Stenosis Exposed to Acceleration-Associated Stress.

This study aimed to investigate the effects of myocardial injury in a minimally-invasive miniature swine model with different levels of coronary artery stenosis (CAS) and exposed to maximal tolerated +Gz. Proximal left anterior descending branch was ligated in 20 swine. Five swine underwent a sham operation. A trapezoid acceleration curve was used for +Gz stress. Pathological changes of myocardial tissue were detected by H&E staining. Apoptotic cardiomyocytes were detected by TUNEL. GRP78 and CHOP were investigated by immunohistochemistry and western blot. CAS models were successful in 18 animals.Compared with the sham-operated group (+8.00±0.71 Gz), the maximal tolerated +Gz values of the moderate stenosis (+6.00±0.89 Gz, P<0.05) and severe stenosis groups (+5.20±0.84 Gz, P<0.05) were decreased.Compared with sham animals (12.16±1.25%), after exposure to maximum +Gz, apoptotic cells of the moderate (43.53±8.42%, P<0.05) and severe stenosis group (60.50±9.35%, P<0.05) were increased, MDA content was increased (1.89 and 4.91 folds, respectively, P<0.05), and SOD activity was reduced (-13.66% and -21.71%, respectively). After exposure to maximum +Gz, GRP78 protein expression was low in the sham-operated (0.29±0.05) and mild stenosis groups (0.35±0.04), while expression was high in the moderate (0.72±0.04, P<0.05) and severe stenosis groups (0.65±0.07, P<0.05). CHOP protein expression was not observed in the sham-operated group, while expression was high in the moderate and severe stenosis groups. These results indicated that Under maximum exposure to +Gz stress, different levels of CAS led to different levels of myocardial injury. Endoplasmic reticulum response is involved in the apoptosis of cardiomyocytes after +Gz stress.

Tyrosine kinase receptor B protects against coronary artery disease and promotes adult vasculature integrity by regulating Ets1-mediated VE-cadherin expression.

OBJECTIVE: Tyrosine kinase receptor B (TrkB) is a high-affinity receptor for brain-derived neurotrophic factor. In addition to its nervous system functions, TrkB is also expressed in the cardiovascular system. However, the association of TrkB and coronary artery disease (CAD) remains unknown. We investigated the role of TrkB in the development of CAD and its mechanism. APPROACH AND RESULTS: We performed a case-control study in 2 independent cohort of Chinese subjects and found -69C>G polymorphisms of TrkB gene significantly associated with CAD. TrkB -69C homozygotes, which corresponded to decreased TrkB expression by luciferase reporter assay, showed increased risk for CAD. Immunofluorescence analysis revealed that TrkB was expressed in the aortic endothelium in atherosclerotic lesions in humans and ApoE(-/-) mice. TrkB knockdown in the aortic endothelium resulted in vascular leakage in ApoE(-/-) mice. Mechanistic studies showed that TrkB regulated vascular endothelial cadherin (VE-cadherin) expression through induction and activation of Ets1 transcriptional factor. Importantly, TrkB activation attenuated proatherosclerotic factors induced-endothelial hyperpermeability in human vascular endothelial cells. CONCLUSIONS: Our data demonstrate that TrkB protects endothelial integrity during atherogenesis by promoting Ets1-mediated VE-cadherin expression and plays a previously unknown protective role in the development of CAD.

Intracoronary insulin administered at reperfusion in a porcine model of acute coronary syndrome.

BACKGROUND: Experimental studies have demonstrated that insulin elicits cardioprotection in coronary occlusion-reperfusion models. We studied the effects of intracoronary insulin on regional cardiac function in a porcine model with reperfusion after a critical coronary artery stenosis. METHODS: In 20 anaesthetized pigs with an extracorporeal shunt from the brachiocephalic to the left anterior descending coronary artery, a fixed stenosis was applied, obtaining 50% reduction of shunt flow for 60 min. Intracoronary insulin 1 1U [DOSAGE ERROR CORRECTED] or 0.9% saline was infused for 15 min, starting 5 min prior to initiation of 180 min of reperfusion. Microsphere injections confirmed ischaemia and reperfusion. Epicardial echocardiographic multilayer radial tissue Doppler strain and strain rate and one-layer speckle-tracking strain evaluated myocardial function. Apoptosis was evaluated by cleaved caspase-3 activity. Area at risk and infarct size were determined with Evans Blue and triphenyltetrazolium chloride staining. RESULTS: In both groups, the area at risk constituted approximately 26% of the left ventricular mass. Minor areas of infarction were predominantly seen subendocardially, where tissue blood flow rate was severely reduced during stenosis. After 180 min of reperfusion, recovery of speckle-tracking circumferential strain averaged 57.5 ± 11.4% of baseline values in insulin treated animals compared to 22.3 ± 8.7% in controls (p = 0.025). Multilayer radial strain and strain rate did not differ between groups. Cleaved caspase-3 activity was most prominent in the subepicardial layer in the saline-treated group. CONCLUSIONS: Intracoronary insulin at the onset of reperfusion alleviated regional myocardial dysfunction in acute ischaemia-reperfusion and was associated with a reduction of apoptosis.

Effects of a timely therapy with doxycycline on the left ventricular remodeling according to the pre-procedural TIMI flow grade in patients with ST-elevation acute myocardial infarction.

Doxycycline has been demonstrated to reduced left ventricular (LV) remodeling, but its effect in patients with ST-elevation myocardial infarction (STEMI) and a baseline occluded [thrombolysis in myocardial infarction (TIMI) flow grade ≤1] infarct-related artery (IRA) is unknown. According to the baseline TIMI flow grade, 110 patients with a first STEMI were divided into 2 groups. Group 1: 77 patients with TIMI flow ≤1 (40 patients treated with doxycycline and 37 with standard therapy, respectively), and a Group 2: 33 patients with TIMI flow 2-3 (15 patients treated with doxycycline and 18 with standard therapy, respectively). The two randomized groups were well matched in baseline characteristics. A 2D-Echo was performed at baseline and at 6 months, together with a coronary angiography, for the remodeling and IRA patency assessment, respectively. The LV end-diastolic volume index (LVEDVi) decreased in Group 2 [-3 mL/m(2) (IQR: -12 to 4 mL/m(2))], and increased in Group 1 [6 mL/m(2) (IQR: -2 to 14 mL/m(2))], (p = 0.001). In Group 2, LVEDVi reduction was similar regardless of drug therapy, while in Group 1 the LVEDVi was smaller in patients treated with doxycycline as compared to control [3 mL/m(2) (IQR: -3 to 8 mL/m(2)) vs. 10 mL/m(2) (IQR: 1-27 mL/m(2)), p = 0.006]. A similar pattern was observed also for LV end-systolic volume and ejection fraction. In STEMI patients at higher risk, as those with a baseline TIMI flow grade ≤1, doxycycline reduces LV remodeling.

Transglutaminase 2 promotes PDGF-mediated activation of PDGFR/Akt1 and ß-catenin signaling in vascular smooth muscle cells and supports neointima formation.

BACKGROUND: Phenotypic switch of vascular smooth muscle cells (VSMCs) accompanies neointima formation and associates with vascular diseases. Platelet-derived growth factor (PDGF)-induced activation of PDGFR/Akt1 and ß-catenin signaling pathways in VSMCs has been implicated in vessel occlusion. Transglutaminase 2 (TG2) regulates these pathways and its levels are increased in the neointima. OBJECTIVE: The aim of this study was to evaluate the role of TG2 in PDGF/ß-catenin signaling cross-talk and assess its contribution to neointima. METHODS: Aortic VSMCs from wild-type and TG2 knockout mice were tested in vitro for levels of VSMC markers, proliferation, migration and PDGF-induced activation of PDGFR/Akt1 and ß-catenin pathways. Neointima in these mice was studied ex vivo in coronary vessels using a heart slice model and in vivo using a carotid artery ligation model. RESULTS: Genetic deletion of TG2 attenuated the PDGF-induced phenotypic switch of aortic VSMCs, reduced their proliferation and migration rates, and inhibited PDGF-induced activation of PDGFR/Akt1 and ß-catenin pathways in both ex vivo and in vivo neointima models. Importantly, genetic deletion of TG2 also markedly attenuated vessel occlusion. CONCLUSIONS: TG2 promotes neointima formation by mediating the PDGF-induced activation of the PDGFR/Akt1 and ß-catenin pathways in VSMCs. This study identifies TG2 as a potential therapeutic target for blocking neointima in blood vessels.

Association of PON1 and PON2 polymorphisms with PON1 activity and significant coronary stenosis in a Tunisian population.

PON1 and PON2 have attracted considerable attention as candidate genes for coronary heart disease because their enzymes function as key factors in lipoprotein catabolism pathways. We studied the distribution of PON1 and PON2 polymorphisms, including genotyping, lipid profile, and PON1 activity, and their association with PON1 activity and significant coronary stenosis (SCS) in a Tunisian population. PON1 activity was lower in patients with SCS than in controls. It increased with the R allele (QQ < QR < RR) in PON1-192 genotypes and with the L allele (MM < ML < LL) in PON1-55 genotypes. In the presence of metabolic syndrome and diabetes, PON1-192RR and PON2-311CC were associated with an increased risk of SCS and PON1-55MM seems to have lower risk. This association was evident among nonsmokers for PON1-55MM and among smokers for PON1-192RR and PON2-311CC. The GTGC haplotype seemed to increase the risk of SCS compared with the wild haplotype in a Tunisian population.

An MTHFR variant, plasma homocysteine levels and late-onset coronary artery disease in subjects from southern Iran.

There have been many controversial debates on the role of Hyperhomocysteinaemia (HHcy) as an independent risk factor for Coronary Artery Disease (CAD) during recent years. Furthermore, an alanine/valine (Ala/Val) gene polymorphism at 222nd amino acid of 5,10-methylenetetrahydrofolate reductase (MTHFR) has been considered as a factor that could render this enzyme thermolabile and less active which in turn may yield a subsequent increase in plasma total homocysteine (tHcy) levels. To assess whether this polymorphism is associated with increased risk of CAD and plasma levels of tHcy in a population from southern Iran, a total of 457 patients with angiographically documented multi-vessel CAD were compared with a control group comprised of 371 subjects with <30% stenosis in all major vessels. Nevertheless our results failed to admit a significant difference between CAD individuals and control subjects for Ala/Val polymorphism and plasma Hcy concentrations. However, plasma Hcy concentrations were significantly higher in individuals with Val/Val genotype than subjects with Ala/Ala genotype, but it didn't show a significant association with CAD in our population. Moreover, as the multiple linear regression analysis indicated, smoking habit, folate levels and the MTHFR Val/Val genotype were the only major predictors of tHcy concentrations in the current investigation.