Elevated Plasma Plasminogen Activator Inhibitor Type-1 is an Independent Predictor of Coronary Microvascular Dysfunction in Hypertension

Circulating Biomarkers in Coronary Microvascular Dysfunction

Coronary microvascular dysfunction is an underdiagnosed pathologic process that is associated with adverse clinical outcomes. Biomarkers, molecules measurable in the blood, could inform the clinician by aiding in the diagnosis and management of coronary microvascular dysfunction. We present an updated review of circulating biomarkers in coronary microvascular dysfunction representing key pathologic processes, including inflammation, endothelial dysfunction, oxidative stress, coagulation, and other mechanisms.

Retinal vasodilatory responses are inversely associated with plasminogen activator inhibitor-1: The African-PREDICT study

AIMS

Plasminogen activator inhibitor-1 (PAI-1), traditionally associated with fibrinolysis, is increasingly implicated in impaired vascular function. However, studies on its association with microvascular function are limited to the cutaneous and coronary microvascular beds in older and diseased individuals. To better understand its potential involvement in the early stages of disease development, we investigated the associations of retinal vasodilatory responses to flicker light with PAI-1 activity (PAI-1_act) in young and healthy individuals.

METHODS

We included healthy Black and White women and men (n = 518; aged 20-30 years), and measured plasma PAI-1_act and retinal vasodilatory responses to flicker light provocation. We also collected demographic and lifestyle data, measured blood pressure, anthropometry, blood lipids, inflammatory and other biomarkers.

RESULTS

In multivariate regression analyses, maximal retinal venular dilation associated independently and inversely with PAI-1_act (adj. R² = 0.11; β = -0.15; p = 0.001) in the total group. In exploratory subgroup analyses, this association remained in White women (adj. R² = 0.07; β = -0.23; p = 0.005), and was more robust with younger age and lower blood pressure and in non-smokers, but also with greater central adiposity, higher low-density lipoprotein cholesterol and inflammation (all p < 0.05).

CONCLUSIONS

Our data suggest that in young individuals, PAI-1 may already be associated with subclinical microvascular dysfunction.

Annexin A2-Mediated Plasminogen Activation in Endothelial Cells Contributes to the Proangiogenic Effect of Adenosine A2A Receptors

Adenosine A_2A receptor mediates the promotion of wound healing and revascularization of injured tissue, in healthy and animals with impaired wound healing, through a mechanism depending upon tissue plasminogen activator (tPA), a component of the fibrinolytic system. In order to evaluate the contribution of plasmin generation in the proangiogenic effect of adenosine A_2A receptor activation, we determined the expression and secretion of t-PA, urokinase plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1) and annexin A2 by human dermal microvascular endothelial cells stimulated by the selective agonist CGS-21680. The plasmin generation was assayed through an enzymatic assay and the proangiogenic effect was studied using an endothelial tube formation assay in Matrigel. Adenosine A_2A receptor activation in endothelial cells diminished the release of PAI-1 and promoted the production of annexin A2, which acts as a cell membrane co-receptor for plasminogen and its activator tPA. Annexin A2 mediated the increased cell membrane-associated plasmin generation in adenosine A_2A receptor agonist treated human dermal microvascular endothelial cells and is required for tube formation in an in vitro model of angiogenesis. These results suggest a novel mechanism by which adenosine A_2A receptor activation promotes angiogenesis: increased endothelial expression of annexin A2, which, in turn, promotes fibrinolysis by binding tPA and plasminogen to the cell surface.

Effects and mechanisms of PSS-loaded nanoparticles on coronary microcirculation dysfunction in streptozotocin-induced diabetic cardiomyopathy rats

Coronary microvascular dysfunction (CMD) is the pathological basis and pathogenesis of diabetic cardiomyopathy (DCM). Propylene glycol alginate sodium sulfate (PSS) as heparinoid drug has many biological activities. Here, a novel PSS-loaded nanoparticle (PSS-NP) was prepared to study its effect on the CMD of DCM. We used diabetes mellitus rat induced by STZ to establish the CMD model of DCM, and the study was detected by echocardiography, histological analysis, transmission electron microscopy, immunofluorescence staining, enzyme-linked immunosorbent assay, real time-PCR analysis, liquid-chip analysis, western blot analysis and so on. The experimental results suggested that PSS-NP could improve the survival state of rats, cardiac function, myocardial morphology and coronary microcirculation structure disorders, and increase the number of microvessels. In addition, we demonstrated that PSS-NP could alleviate the CMD by improving endothelial function, anticoagulation and antioxidative stress. The outcomes of this study provided new treatment thoughts for the therapy of coronary microcirculation dysfunction in DCM.

Evaluation of Serum Levels of Inflammation, Fibrinolysis and Oxidative Stress Markers in Coronary Artery Disease Prediction: A Cross-Sectional Study

Background

Coronary Artery Disease (CAD) has long been recognized as a global health issue. Inflammation, Fibrinolysis and Oxidative Stress play an important role in the disruption of plaques leading to CAD. Markers that reflect this pathophysiologic mechanism may have prognostic value.

Objective

To estimate the serum concentrations of high-sensitivity C-reactive protein (hs-CRP), sialic acid (SA), vitronectin (VN), plasminogen activator inhibitor-1 (PAI-1), oxidized low density lipoprotein (OX-LDL) and malondialdehyde (MDA) with significant prognostic value in patients with CAD.

Methods

The markers included, hs-CRP, SA, VN, PAI-1, OX-LDL and MDA, were compared between 160 angiographically diagnosed CAD patients and 20 age- and sex-matched healthy individuals. The subjects were divided into 4 groups according to angiography results, and association between all risk factors of CAD was studied. Serum levels of SA, VN, PAI-1, and OX-LDL were measured by enzyme-linked immunosorbent assay (ELISA); MDA was measured based on reaction with thiobarbituric acid (TBA); and hs-CRP level was estimated by immunoturbidimetry using a commercial kit. The diagnostic value of these variables was further assessed by ROC curve analysis. Multiple logistic regression was used to evaluate the diagnostic power of the combination. Furthermore, p < 0.05 was considered as significant.

Results

Serum levels of hs-CRP, SA, VN, PAI-1, and OX-LDL were significantly higher in patient groups compared to control group (p < 0.001). Using both normal and CAD patients as subjects, ROC analysis was performed. The cutoff for OX-LDL, MDA, PAI-1, VN, hs-CRP and SA was 2.67 (ug/mL), 5.49 (mmol/mL), 67 (ng/mL), 254 (ng/mL), 3.4 (mg/dL), 7/89 (mg/dL), respectively. Eventually, the complete diagnostic efficacy was classified as: SA, hs-CRP, PAI-1, OX-LDL, MDA and VN.

Conclusion

Serum levels SA, hs-CRP, VN, PAI-1, OX-LDL and MDA may be predictive of adverse cardiovascular outcomes. Interestingly, these analyses can help as diagnostic and monitoring markers in CAD patients.

Novel biomarkers of coronary microvascular disease

Coronary microvascular disease in the absence of myocardial diseases has traditionally been diagnosed through coronary reactivity testing in the cardiac catheterization laboratory. Compared with invasive procedures, blood-based biomarkers may have reduced cost, less risk of physical harm and greater accessibility, making them ideal for an outpatient management strategy. There are a variety of biomarkers available with potential utility in the management of microvascular disease; however, none have yet been extensively validated or established in this clinical patient population.

Coronary flow reserve estimated by positron emission tomography to diagnose significant coronary artery disease and predict cardiac events

Coronary artery disease (CAD) is a major cause of death in Japan. Coronary angiography is useful to assess the atherosclerotic burden in CAD patients, but its ability to predict whether patients will respond favorably to optimal medical therapy and revascularization is limited. The measurement of the fractional flow reserve with angiography is a well-validated method for identifying ischemic vessels. However, neither an anatomical assessment nor a functional assessment can delineate microvasculature or estimate its function. The quantitative coronary flow reserve (CFR) estimated from sequential myocardial perfusion images obtained by positron emission tomography (PET) during stress provides an accurate index of hyperemic reactivity to vasodilatory agents in the myocardium. In fact, there is growing evidence that the CFR reflects disease activity in the entire coronary circulation, including epicardial coronary artery stenosis, diffuse atherosclerosis, and microvascular dilatory function. Importantly, reduced CFR is observed even in patients without flow-limiting coronary stenosis, and its evaluation can improve the risk stratification of patients at any stage of CAD. This review focuses on the application of CFR estimated by cardiac PET for the diagnosis and risk stratification of patients with CAD.

Statins suppress glucose-induced plasminogen activator inhibitor-1 expression by regulating RhoA and nuclear factor-κB activities in cardiac microvascular endothelial cells

The aim of this study was to investigate the possible proinflammatory signaling pathways involved in statin inhibition of glucose-induced plasminogen activator inhibitor-1 (PAI-1) expression in cardiac microvascular endothelial cells (CMECs). Primary rat CMECs were grown in the presence of 5.7 or 23 mmol/L glucose. PAI-1 mRNA and protein expression levels were measured by realtime polymerase chain reaction, Western blotting and enzyme-linked immunosorbent assay, respectively. A pull-down assay was performed to determine RhoA activity. IκBα protein expression was measured by Western blotting, nuclear factor (NF)-κB activation was detected by electrophoretic mobility shift assay and its transcription activity was determined by a dual luciferase reporter gene assay. PAI-1 mRNA and protein expression levels were both increased with high glucose concentrations, but they were significantly suppressed by simvastatin and atorvastatin treatment (P < 0.01) and the effects were reversed by mevalonate (100 μmol/L) and geranylgeranyl pyrophosphate (10 μmol/L) but not farnesyl pyrophosphate (10 μmol/L). Such effects were similar to those of a RhoA inhibitor, C3 exoenzyme (5 μg/mL), inhibitors of RhoA kinase (ROCK), Y-27632 (10 μmol/L) and hydroxyfasudil (10 μmol/L) and an NF-κB inhibitor, BAY 11-7082 (5 μmol/L). High glucose-induced RhoA and NF-κB activations in CMECs were both significantly inhibited by statins (P < 0.01). Simvastatin and atorvastatin equally suppress high glucose-induced PAI-1 expression. These effects of statins may occur partly by regulating the RhoA/ROCK-NF-κB pathway. The multifunctional roles of statins may be particularly beneficial for patients with metabolic syndrome.

Impaired myocardial blood flow reserve in subjects with metabolic syndrome analyzed using positron emission tomography and N-13 labeled ammonia

PURPOSE

Coronary vasomotor response might be impaired in metabolic syndrome (MS); however, the precise abnormality has not been elucidated. The aim of this study was to assess coronary-vasomotor response in MS subjects using N-13 labeled ammonia and positron emission tomography.

METHODS AND RESULTS

Myocardial blood flow (MBF) was measured at rest and during adenosine infusion in MS subjects (n = 13, MS group) with no definite evidence of heart disease and in subjects without MS (n = 14, non-MS group). Coronary vascular resistance (CVR) was calculated by dividing the mean aortic blood pressure by MBF. Myocardial blood flow reserve (MFR) was calculated as the ratio of the MBF during adenosine infusion to that during rest. Blood chemical parameters were measured to evaluate their relationship with MFR. During adenosine infusion, MBF was lower (p = 0.0085) and CVR higher (p = 0.0128) in the MS group than in the non-MS group and MFR was significantly lower in the MS group than in the non-MS group (2.13 +/- 0.99 vs. 3.38 +/- 0.95, p = 0.0027). Multivariate analysis demonstrated that the homeostasis model assessment-insulin resistance (p < 0.05) and the presence of hypertension (p < 0.05) were independent determinants of MFR.

CONCLUSIONS

The results indicate that MFR was impaired in MS subjects, suggesting that an abnormal coronary microvascular response occurred in these subjects. This abnormality may have been partially due to insulin resistance and hypertension.

Hypercoagulability markers in patients with peripheral arterial disease: association to ankle-brachial index

Peripheral arterial disease is diagnosed by measuring the ankle-brachial index. Values lower than 0.90 define the disease being usually related to its severity. Patients with peripheral arterial disease may show a hypercoagulability state. The aim of this study was to assess hemostatic variables and to correlate them with the presence of peripheral arterial disease and its severity as assessed by ankle-brachial index values. Plasma levels of D dimer, plasminogen, prothrombin fragment 1+2, plasminogen activator inhibitor and thrombomodulin were measured in 36 patients with peripheral arterial disease (group 1) and 30 without disease (group 2). Significant differences for D dimer, plasminogen, prothrombin fragment 1+2 and plasminogen activator inhibitor type 1 between the 2 groups were found (P<0.05). Significant and inverse correlations were also observed (Pearson correlation, P<0.05) between ankle-brachial index values and levels of both plasminogen and plasminogen activator inhibitor type 1. Although there was no significant correlation between ankle-brachial index and levels of D dimer, higher D dimer values were observed in patients with lower ankle-brachial index values. The results confirm a trend to hypercoagulability and hypofibrinolysis in patients with peripheral arterial disease. Increased levels of plasminogen activator inhibitor type 1 seem to be associated with the severity of the disease, considering the inverse correlation between this inhibitor and ankle-brachial index.

Multifocal, persistent cardiac uptake of [18-F]-fluoro-deoxy-glucose detected by positron emission tomography in patients with acute myocardial infarction

BACKGROUND

Inflammation appears to be important in the pathogenesis of acute myocardial infarction (AMI).

METHODS AND RESULTS

Cardiac [18-F]-fluoro-deoxy-glucose (FDG) uptake by positron emission tomography/computed tomography (PET/CT)-scan was investigated in 12 fasting patients with first AMI (FAMI) single-vessel disease after successful primary percutaneous coronary intervention and at 9 weeks follow-up, and in 12 controls. The average FDG uptake (aFDGu) of the 28 left ventricular (LV) wall segments defined on the PET/CT images of the 12 FAMI patients was 1.28+/-0.57-fold higher than the activity present in the LV cavity. By contrast, the aFDGu of the 12 controls was 0.70+/-22 (p<0.001). The segmental aFDGu in the FAMI was multifocal in both the culprit and non-culprit segments; it was less than LV cavity activity in 38%, 1-2-fold greater in 51.8% and more than 2-fold greater in 10.2%. At follow-up, aFDGu was significantly increased in both culprit and non-culprit segments (1.69+/-1.15, p<0.001). Statistically significant differences between FAMI and controls patients were only found for interleukin-6 plasma levels on admission (11.3+/-7.7 pg/ml vs 2.2+/-1.3 pg/ml; p<0.004).

CONCLUSION

Multifocal, non-infarct related, cardiac-FDG-uptake occurred immediately after AMI and persisted at follow-up. The cause of these striking and consistent findings is still speculative.

Altered interaction between plasminogen activator inhibitor type 1 activity and sympathetic nerve activity with aging

BACKGROUND

It has been reported that sympathetic nerve activity (SNA) is associated with fibrinolysis, but the interaction between SNA and the fibrinolytic system with aging has not been elucidated in humans. The purpose of this study was to examine the effect of age-related SNA on the activity of plasminogen activator inhibitor type 1 (PAI-1) and tissue plasminogen activator (tPA) using muscle SNA (MSNA).

METHODS AND RESULTS

This study included 16 young subjects (mean age 26.1 years) and 10 aged subjects (mean age 56.9 years). Lower body negative pressure (LBNP) was performed at -40 mmHg for 30 min. LBNP significantly increased both tPA and PAI-1 activity (from 5.2+/-0.5 to 7.3+/-1.2 IU/ml and from 2.85+/-0.68 to 4.06+/-0.73 U/ml, p<0.01, respectively) in the aged group. In the young group, tPA activity tended to increase, whereas PAI-1 activity was unchanged. There was a correlation between MSNA and PAI-1 activity in the aged group (r=0.47, p<0.01).

CONCLUSIONS

SNA in an aging subject leads to an increase in the activity of PAI-1, which indicates that an altered interaction between SNA and PAI-1 activity contributes to increased cardiovascular events in the elderly population.