Association of fibrinolytic parameters with early atherosclerosis. The ARIC Study. Atherosclerosis Risk in Communities Study

Potential mechanisms of ischemic stroke induced by heat exposure

Recent decades of epidemiological and clinical research have suggested that heat exposure could be a potential risk factor for ischemic stroke. Despite climate factors having a minor impact on individuals compared with established risk factors such as smoking, their widespread and persistent effects significantly affect public health. The mechanisms by which heat exposure triggers ischemic stroke are currently unclear. However, several potential mechanisms, such as the impact of temperature variability on stroke risk factors, inflammation, oxidative stress, and coagulation system changes, have been proposed. This article details the potential mechanisms by which heat exposure may induce ischemic stroke, aiming to guide the prevention and treatment of high-risk groups in hot climates and support public health policy development.

Development of a Hypercoagulable-Hypofibrinolytic State Early After Spinal Cord Injury

OBJECTIVES

To determine whether spinal cord injury (SCI) is associated with adverse changes in coagulation and fibrinolytic factors that underlie thrombogenesis and contribute to atherothrombotic events such as myocardial infarctions (MIs) and strokes.

DESIGN

Cross-sectional study.

SETTING

Neurorehabilitation hospital and general community.

PARTICIPANTS

Thirty young and middle-aged (20-58 years) adults (N=30) were studied: 14 non-injured community dwelling adults. (11M/4F) and 16 with subacute tetraplegic motor complete SCI during initial inpatient rehabilitation (13M/3F; time since injury: 11.8±5.3 wk).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Circulating markers of coagulation [von Willebrand factor (vWf) and factors VII, VIII, and X], the fibrinolytic system [tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor-1 (PAI-1) antigen and activity], and fibrin formation (D-dimer) were determined by enzyme immunoassay.

RESULTS

Thirty young and middle-aged (20-58 years) adults were studied: 14 non-injured (11M/4F) and 16 with subacute tetraplegic motor complete SCI (13M/3F; time since injury: range 4-25 wk). Circulating levels of coagulation factors VII, VIII, and X were significantly higher (∼20%-45%; P<.05) in the adults with SCI than non-injured adults, whereas vWf was similar between groups. Fibrinolytic markers were adversely disrupted with SCI with t-PA antigen, PAI-1 antigen and PAI-1 activity were markedly higher (∼50%-800%; P<.05) in adults with SCI compared with non-injured adults. The molar concentration ratio of active t-PA to PAI-1 was significantly higher (∼350%) in adults with SCI. Concordant with coagulation cascade activation and fibrinolytic system inhibition, D-dimer concentrations were markedly ∼70% higher (P<.05) in adults with SCI compared with non-injured adults.

CONCLUSIONS

Subacute tetraplegic motor complete SCI is associated with a prothrombotic hemostatic profile. Adverse changes in the coagulation cascade and fibrinolytic system appear to occur early after injury and may contribute to the increased atherothrombotic risk in adults living with SCI.

Predictors of functional and morphological arterial wall properties in coronary artery disease patients with increased lipoprotein (a) levels before and after treatment with proprotein convertase subtilisin-kexin type 9 inhibitors

BACKGROUND

In addition to proatherogenic properties, lipoprotein (a) (Lp(a)) has also pro-inflammatory, antifibrinolytic and prothrombogenic features. The aim of the current study was to identify the predictors of functional and morphological properties of the arterial wall in patients after myocardial infarction and increased Lp(a) levels at the beginning and after treatment with proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors.

METHODS

Seventy-six post-myocardial infarction patients with high Lp(a) levels were included in the study. Ultrasound measurements of flow-mediated dilation of brachial artery (FMD), carotid intima-media thickness (c-IMT) and pulse wave velocity (PWV) were performed initially and after 6 months of treatment. At the same time points lipids, Lp(a), inflammatory and hemostasis markers were measured in blood samples.

RESULTS

In linear regression model FMD significantly correlated with age at first myocardial infarction (β = 0.689; p = 0.022), high-sensitivity C-reactive protein (β = -1.200; p = 0.009), vascular cell adhesion protein 1 (VCAM-1) (β = -0.992; p = 0.006), overall coagulation potential (β = 1.428; p = 0.014) and overall hemostasis potential (β = -1.473; p = 0.008). c-IMT significantly correlated with age at first myocardial infarction (β = 0.574; p = 0.033) and Lp(a) (β = 0.524; p = 0.040). PWV significantly correlated with systolic blood pressure (β = 0.332; p = 0.002), tumor necrosis factor alpha (β = 0.406; p = 0.002), interleukin-8 (β = -0.315; p = 0.015) and plasminogen activator inhibitor 1 (β = 0.229; p = 0.031). After treatment FMD reached statistical significance only in univariant analysis with systolic blood pressure (r = -0.286; p = 0.004) and VCAM-1 (r = -0.229; p = 0.024). PWV and c-IMT correlated with age (r = 0.334; p = 0.001 and r = 0.486; p < 0.0001, respectively) and systolic blood pressure (r = 0.556; p < 0.0001 and r = 0.233; p = 0.021, respectively).

CONCLUSIONS

Our results suggest that age, systolic blood pressure, Lp(a) levels and other biochemical markers associated with Lp(a) are predictors of functional and morphological properties of the arterial vessel wall in post-myocardial patients with high Lp(a) levels initially. However, after 6 months of treatment with PCSK9 inhibitors only age and systolic blood pressure seem to be predictors of these properties.

TRIAL REGISTRATION

The protocol for this study was registered with clinicaltrials.gov on November, 3 2020 under registration number NCT04613167.

Cardiovascular Disease in Testicular Cancer Survivors: Identification of Risk Factors and Impact on Quality of Life

PURPOSE

Testicular cancer (TC) treatment is clearly associated with cardiovascular morbidity and mortality. To enable development of preventive strategies for cardiovascular disease (CVD), we assessed cardiometabolic risk factors and quality of life (QoL) in TC survivors.

METHODS

Incidence of coronary artery disease, myocardial infarction, and heart failure after TC treatment was assessed in a multicenter cohort comprising 4,748 patients treated at the age of 12-50 years between 1976 and 2007. Patients who had developed CVD and a random sample from the cohort (subcohort) received a questionnaire on cardiometabolic risk factors and QoL. A subgroup of responders in the subcohort additionally underwent clinical evaluation of cardiovascular risk factors.

RESULTS

After a median follow-up of 16 years, 272 patients had developed CVD. Compared with orchidectomy only, cisplatin combination chemotherapy was associated with an increased CVD risk (hazard ratio [HR], 1.9; 95% CI, 1.1 to 3.1). Patients who were obese or a smoker at diagnosis (HR, 4.6; 95% CI, 2.0 to 10.0 and HR, 1.7; 95% CI, 1.1 to 2.4, respectively), developed Raynaud's phenomenon (HR, 1.9; 95% CI, 1.1 to 3.6) or dyslipidemia (HR, 2.8; 95% CI, 1.6 to 4.7) or had a positive family history for CVD (HR, 2.9; 95% CI, 1.7 to 4.9) had higher CVD risk. More TC survivors with CVD reported inferior QoL on physical domains than survivors who did not develop CVD. Of 304 TC survivors who underwent clinical evaluation for cardiovascular risk factors (median age at assessment: 51 years), 86% had dyslipidemia, 50% had hypertension, and 35% had metabolic syndrome, irrespective of treatment.

CONCLUSION

Cardiovascular events in TC survivors impair QoL. Many TC survivors have undetected cardiovascular risk factors. We advocate early lifestyle adjustments and lifelong follow-up with low-threshold treatment of cardiovascular risk factors, especially in obese and smoking patients treated with platinum-based chemotherapy.

Investigating the two regimes of fibrin clot lysis: an experimental and computational approach

It has been observed in vitro that complete clot lysis is generally preceded by a slow phase of lysis during which the degradation seems to be inefficient. However, this slow regime was merely noticed, but not yet quantitatively discussed. In our experiments, we observed that the lysis ubiquitously occurred in two distinct regimes, a slow and a fast lysis regime. We quantified extensively the duration of these regimes for a wide spectrum of experimental conditions and found that on average, the slow regime lasts longer than the fast one, meaning that during most of the process, the lysis is ineffective. We proposed a computational model in which the properties of the binding of the proteins change during the lysis: first, the biochemical reactions take place at the surface of the fibrin fibers, then in the bulk, resulting in the observed fast lysis regime. This simple hypothesis appeared to be sufficient to reproduce with a great accuracy the lysis profiles obtained experimentally.

Global REACH 2018: Influence of excessive erythrocytosis on coagulation and fibrinolytic factors in Andean highlanders

NEW FINDINGS

What is the central question of this study? Are coagulation and fibrinolytic factors disrupted in Andean highlanders with excessive erythrocytosis? What is the main finding and its importance? Excessive erythrocytosis is not associated with prothombotic disruptions in coagulation or the fibrinolytic system in Andean highlanders. Impairments in coagulation and fibrinolysis may not contribute to the increased vascular risk associated with excessive erythrocytosis.

ABSTRACT

Increased coagulation and reduced fibrinolysis are central factors underlying thrombotic risk and events. High altitude-induced excessive erythrocytosis (EE) is prevalent in Andean highlanders, contributing to increased cardiovascular risk. Disruption in the coagulation-fibrinolytic axis resulting in uncontrolled fibrin deposition might underlie the increased thrombotic risk associated with high-altitude EE. The experimental aim of this study was to determine whether EE is associated with a prothrombotic blood coagulation and fibrinolytic profile in Andean highlanders. Plasma coagulation factors (von Willebrand factor and factors VII, VIII and X), fibrinolytic factors [tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1)] and D-dimer levels were determined in 26 male residents of Cerro de Pasco, Peru (4340 m a.s.l.): 12 without EE (age, 40 ± 13 years; haemoglobin, 17.4 ± 1.9 g/dl) and 14 with EE (age, 43 ± 15 years; haemoglobin, 24.4 ± 1.6 g/dl). There were no significant differences in von Willebrand factor (40.5 ± 24.8 vs. 45.5 ± 22.4%), factor VII (77.0 ± 14.5 vs. 72.5 ± 8.9%), factor VIII (55.6 ± 19.8 vs. 60.7 ± 26.8%) and factor X (73.9 ± 8.3 vs. 67.3 ± 10.9%) between the Andean highlanders without or with EE. The t-PA antigen (8.5 ± 3.6 vs. 9.6 ± 5.4 ng/ml), t-PA activity (5.5 ± 2.4 vs. 5.8 ± 1.6 IU/ml), PAI antigen (45.0 ± 33.8 vs. 40.5 ± 15.8 ng/ml), PAI-1 activity (0.24 ± 0.09 vs. 0.25 ± 0.11 IU/ml) and the molar concentration ratio of active t-PA to active PAI-1 (1:0.051 ± 0.034 vs. 1:0.046 ± 0.021 mmol/l) were also similar between the groups, as were D-dimer levels (235.0 ± 126.4 vs. 268.4 ± 173.7 ng/ml). Collectively, the results of the present study indicate that EE is not associated with a hypercoagulable, hypofibrinolytic state in Andean highlanders.

NF-κB and tPA Signaling in Kidney and Other Diseases

The activation of the nuclear factor-κB (NF-κB) pathway plays a central role in the initiation and progression of inflammation, which contributes to the pathogenesis and progression of various human diseases including kidney, brain, and other diseases. Tissue plasminogen activator (tPA), a serine protease regulating homeostasis of blood coagulation, fibrinolysis, and matrix degradation, has been shown to act as a cytokine to trigger profound receptor-mediated intracellular events, modulate the NF-κB pathway, and mediate organ dysfunction and injury. In this review, we focus on the current understanding of NF-κB and tPA signaling in the development and progression of kidney disease. Their roles in the nervous and cardiovascular system are also briefly discussed.

Unstable Carotid Plaque is Associated With Coagulation Function and Platelet Activity Evaluated by Thrombelastography

BACKGROUND

Rupture of unstable carotid plaque and consequently occlusive thrombus formation for the most part cause ischemic cerebral vascular event. Many researchers have been studying on the risk predictors of carotid plaque formation. But the risk factors for unstable carotid plaque have not been researched for so much. In the current study, we aimed to evaluate the association of coagulation function and carotid plaque especially unstable plaque by thrombelastography (TEG).

METHODS

This was a cross-sectional study. Consecutive eligible patients with acute ischemic stroke were included and their TEG data were collected. Carotid plaque was evaluated by carotid ultrasound. Echolucent plaque and heterogeneous echo plaque in ultrasound were classified as unstable carotid plaque. Patients were classified according to being with carotid plaque or unstable plaque for comparison.

RESULTS

Four hundred and seven patients were enrolled. Compared to those without carotid plaques, patients with carotid plaques had higher ages, higher incidence of hypertension and diabetes mellitus, lower k (P = .017) and higher angle (P = .021) on TEG. In the comparison between groups with unstable plaque and stable plaque, no significant difference was found in baseline characteristics; higher serum fibrinogen and higher maximum amplitude on TEG were significantly correlated to unstable carotid plaques (P = .051, P = .009). Multivariate logistic analysis revealed that age, hypertension, and smoking were independent risk factors of carotid plaques formation; higher serum fibrinogen was an independent risk factor of unstable plaques formation.

CONCLUSIONS

This study demonstrates that carotid plaques formation in ischemic stroke patients has a link to abnormal coagulation function, while high platelet activity has an additional contribution to unstable plaque formation.

Regulatory role of metallothionein-1/2 on development of sex differences in a high-fat diet-induced obesity

AIMS

To evaluate the role of metallothionein (MT) in sex differences of obesity, we examined the effect of MT on regulation of lipid accumulation in female and male wild type (WT) and MT1/MT2-null (MT-KO) mice.

MAIN METHODS

Male and female WT and MT-KO mice fed standard diet (SD) or high-fat diet (HFD) for 35 weeks. Surgical castration in male mice was also performed to examine the effects of androgen on fat accumulation under HFD condition.

KEY FINDINGS

The fat mass and size of adipocytes in white adipose tissue (WAT) was greater in adult MT-KO mice than in WT mice after 35 weeks of SD feeding without gender differences, suggesting a role of MT in limiting WAT development during normal growth in both sexes. In female mice fed HFD, weights of WAT and body were greater in MT-KO mice than in WT mice, indicating that MT had a preventive role against excess fat accumulation. In male mice fed HFD, WAT weight hardly increased in MT-KO mice compared to the increase in WT mice. Surgically castrated WT males fed HFD had lower WAT weight compared with sham-treated mice, although castrated MT-KO males fed HFD had greater increases in WAT weight compared with sham-treated mice and castrated WT males.

SIGNIFICANCE

These data suggest that MT could enhance the preventive action of estrogen against excess fat accumulation, on the contrary, MT augmented the ability of androgen to increase fat accumulation. MT may act to modify the susceptibility to obesity under sex hormones.

Carotid plaque composition by CT angiography in asymptomatic subjects: a head-to-head comparison to ultrasound

OBJECTIVES

To describe carotid plaque composition by computed tomography angiography (CTA) in asymptomatic subjects and to compare this to carotid plaque assessment by ultrasound, coronary plaques by coronary CTA, and inflammatory biomarkers in plasma.

METHODS

Middle-aged asymptomatic men, n = 43, without known cardiovascular disease and diabetes were included. Plaques in coronary and carotid arteries were evaluated using CTA. Total plaque volumes and plaque composition were assessed by a validated plaque analysis software. The 60% centile cut point was used to divide the population into low or high carotid total plaque volumes. The occurrence of carotid plaques and intima-media thickness (IMT) was estimated by ultrasound.

RESULTS

Carotid plaque by ultrasound was undiagnosed in 13 of 28 participants (46%) compared to CTA. Participants having carotid plaques by ultrasound had significantly higher absolute volumes of all CTA-defined carotid plaque subtypes and a higher fraction of calcified plaque. A high carotid total plaque volume was independently associated with age (adjusted odds ratio (OR) 1.41 [95% confidence interval (CI) 1.14-1.74], p = 0.001), IMT (adjusted OR 2.26 [95% CI 1.10-4.65], p = 0.03), and D-dimer (adjusted OR 8.86 [95% CI 1.26-62.37], p = 0.03). All coronary plaque features were significantly higher in participants with a high carotid total plaque volume.

CONCLUSION

The occurrence of carotid plaques in asymptomatic individuals is underestimated by ultrasound compared to plaque assessment by CTA. Carotid plaque composition by CTA is different in individuals with and without carotid plaques by ultrasound.

KEY POINTS

• The occurrence of carotid plaques by ultrasound was underestimated in 46% of participants who had plaques by carotid CTA. • Participants with carotid plaques by ultrasound had higher volumes of all plaque subtypes and a higher calcified plaque component as determined by carotid CTA compared to participants without carotid plaques by ultrasound. • A high carotid total plaque volume was independently associated with age, intima-media thickness, and D-dimer.

Plasminogen activator inhibitor 1 in acute coronary syndromes

Plasminogen activator inhibitor 1 (PAI-1) is the main regulator of endogenous fibrinolysis, overriding the impact of other constituents of fibrinolysis. In plasma, it can be found in three forms: active, latent and inactive. There are numerous commercially available tests, analysing the activity of PAI-1 or the antigen level, with variable correlations between the two. PAI-1 has been extensively studied regarding incidence and outcomes of acute coronary syndromes, and showed positive association with both in numerous studies. Higher PAI-1 has been associated with worse short- and long-term outcomes. Studies are more consistent in the primary percutaneous coronary intervention era. Higher rise of PAI-1 within the first 24 h of acute myocardial infarction has been linked to some of its high-risk features. The circadian pattern of PAI-1 kinetics has been previously described, and the mechanisms behind this phenomenon and its impact on the incidence of acute coronary syndromes are well known. Further investigations are needed to test the safety and efficacy of PAI-1 as a pharmacological target in cardiovascular diseases.

Causal Effect of Plasminogen Activator Inhibitor Type 1 on Coronary Heart Disease

Background

Plasminogen activator inhibitor type 1 (PAI‐1) plays an essential role in the fibrinolysis system and thrombosis. Population studies have reported that blood PAI‐1 levels are associated with increased risk of coronary heart disease (CHD). However, it is unclear whether the association reflects a causal influence of PAI‐1 on CHD risk.

Methods and Results

To evaluate the association between PAI‐1 and CHD, we applied a 3‐step strategy. First, we investigated the observational association between PAI‐1 and CHD incidence using a systematic review based on a literature search for PAI‐1 and CHD studies. Second, we explored the causal association between PAI‐1 and CHD using a Mendelian randomization approach using summary statistics from large genome‐wide association studies. Finally, we explored the causal effect of PAI‐1 on cardiovascular risk factors including metabolic and subclinical atherosclerosis measures. In the systematic meta‐analysis, the highest quantile of blood PAI‐1 level was associated with higher CHD risk comparing with the lowest quantile (odds ratio=2.17; 95% CI: 1.53, 3.07) in an age‐ and sex‐adjusted model. The effect size was reduced in studies using a multivariable‐adjusted model (odds ratio=1.46; 95% CI: 1.13, 1.88). The Mendelian randomization analyses suggested a causal effect of increased PAI‐1 level on CHD risk (odds ratio=1.22 per unit increase of log‐transformed PAI‐1; 95% CI: 1.01, 1.47). In addition, we also detected a causal effect of PAI‐1 on elevating blood glucose and high‐density lipoprotein cholesterol.

Conclusions

Our study indicates a causal effect of elevated PAI‐1 level on CHD risk, which may be mediated by glucose dysfunction.

Monoclonal antibodies with equal specificity to D-dimer and high-molecular-weight fibrin degradation products

Fibrin degradation results in the formation of fibrin degradation products (FDPs) of different molecular weights, which include D-dimer. Commercial D-dimer assays recognize multiple forms of FDP with different specificity. As a result, the absence of an international D-dimer standard and the marked discrepancy in the D-dimer values in the same samples measured by assays from different manufacturers have become the primary problems that clinicians face in the D-dimer determination. We consider that an assay with equal specificity to all FDP forms regardless of their molecular weights could help to solve these problems. We aimed to produce mAbs that could equally recognize high-molecular-weight FDP (HMW FDP) and D-dimer. mAbs against D-dimer were produced. The HMW FDP/D-dimer ratios in plasma samples were analyzed following protein separation by gel filtration using the developed fluoroimmunoassay. A sandwich immunoassay with equal specificity to HMW FDP and D-dimer was developed and applied to determine HMW FDP/D-dimer ratios in patients with different diseases. Although the HMW FDP levels prevailed in thrombotic patients, the FDP and D-dimer levels were comparable in septic patients. Meanwhile, the D-dimer levels often exceeded the HMW FDP levels in patients who had undergone surgery. The 'D-dimer' levels that were detected by different assays also varied greatly depending on the assay specificities to FDP and D-dimer. Our findings show that the introduction of assays with equal specificities to FDP and D-dimer in clinical practice is a possible way of standardizing D-dimer measurements.

The effect of acute aerobic exercise on hemostasis in obstructive sleep apnea

PURPOSE

Individuals with obstructive sleep apnea (OSA) have an altered hemostatic balance; however, the exercise response is less described. The purpose of this study is to determine the hemostatic response after acute aerobic exercise in obstructive sleep apnea.

METHODS

Eighteen males (nine OSA vs. nine controls) were recruited from the university and local community. Individuals with evidence of cardiovascular, pulmonary, or metabolic disease were excluded. An apnea-hypopnea index (AHI) of >5 was a criterion for OSA. Subjects performed a treadmill exercise test at 35 and 70% predicted VO₂ reserve during the morning hours. Pre-exercise blood samples were obtained after 15 min supine rest and within 2 min following exercise. Repeated measures ANOVA were performed for factor VIII antigen, tissue plasminogen activator (tPA) antigen, tPA activity, and PAI-1 activity. Correlational analysis compared resting and post-exercise hemostatic factors with age, BMI, and AHI.

RESULTS

Mean AHI was 13.00 ± 12.6. No exercise × condition interactions were observed for hemostatic markers. There was a main effect for exercise in factor VIII, tPA antigen, and tPA activity in both groups. PAI-1 activity tended to be elevated in OSA (145%) compared to controls which remained after exercise (205%) (P = 0.05). Post-exercise FVIII/Ag correlated with BMI (r = 0.52), while resting tPA/Ag correlated with AHI (r = 0.49) and age (r = 0.50).

CONCLUSION

The hemostatic response after acute aerobic exercise is unaffected in mild OSA, although PAI-1 activity seems to be elevated, reducing fibrinolytic potential. BMI seems to correlate with FVIII/Ag, while tPA/Ag is associated with AHI and age.

The effects of residual platelets in plasma on plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays

Due to controversial evidence in the literature pertaining to the activity of plasminogen activator inhibitor-1 in platelets, we examined the effects of residual platelets present in plasma (a potential pre-analytical variable) on various plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays. Blood samples were collected from 151 individuals and centrifuged at 352 and 1500 g to obtain plasma with varying numbers of platelet. In a follow-up study, blood samples were collected from an additional 23 individuals, from whom platelet-poor (2000 g), platelet-containing (352 g) and platelet-rich plasma (200 g) were prepared and analysed as fresh-frozen and after five defrost-refreeze cycles (to determine the contribution of in vitro platelet degradation). Plasminogen activator inhibitor-1 activity, plasminogen activator inhibitor-1 antigen, tissue plasminogen activator/plasminogen activator inhibitor-1 complex, plasma clot lysis time, β-thromboglobulin and plasma platelet count were analysed. Platelet α-granule release (plasma β-thromboglobulin) showed a significant association with plasminogen activator inhibitor-1 antigen levels but weak associations with plasminogen activator inhibitor-1 activity and a functional marker of fibrinolysis, clot lysis time. Upon dividing the study population into quartiles based on β-thromboglobulin levels, plasminogen activator inhibitor-1 antigen increased significantly across the quartiles while plasminogen activator inhibitor-1 activity and clot lysis time tended to increase in the 4^th quartile only. In the follow-up study, plasma plasminogen activator inhibitor-1 antigen was also significantly influenced by platelet count in a concentration-dependent manner. Plasma plasminogen activator inhibitor-1 antigen levels increased further after complete platelet degradation. Residual platelets in plasma significantly influence plasma plasminogen activator inhibitor-1 antigen levels mainly through release of latent plasminogen activator inhibitor-1 with limited effects on plasminogen activator inhibitor-1 activity, tissue plasminogen activator/plasminogen activator inhibitor-1 complex or plasma clot lysis time. Platelets may however also have functional effects on plasma fibrinolytic potential in the presence of high platelet counts, such as in platelet-rich plasma.

Evaluation of Early Atherosclerosis Markers in Patients with Inflammatory Bowel Disease

BACKGROUND The aim of this study was to investigate relationships between early atherosclerosis and inflammatory bowel disease (IBD) using laboratory, functional, and morphological markers of atherosclerosis. MATERIAL AND METHODS In the present prospective single-center study, 96 patients with IBD (58 patients with ulcerative colitis and 36 patients with Crohn's disease) and 65 healthy control subjects were included. The demographic data of each patient and control subject were recorded. The patients with IBD and healthy controls were compared in terms of the carotid intima-media thickness (CIMT), the values of flow-mediated dilatation (FMD) and nitroglycerine-mediated dilatation (NMD), and the levels of von Willebrand factor antigen (VWF-Ag), D-dimer, and lipoprotein (a). RESULTS There were no significant differences between the IBD patients and controls in terms of age, sex, BMI, systolic and diastolic BPs, serum levels of total cholesterol, low-density lipoprotein, or triglycerides. IBD patients had significantly higher levels of VWF-Ag (156.6±58.9 vs. 104.2±43.3, P<0.001) and D-dimer (337.2±710.8 vs. 175.9±110.9, P<0.001) as compared to the controls. No significant differences were determined between the 2 groups in terms of FMD and NMD values. Although statistically not significant, the CIMT values were higher in the IBD patients than in the controls (0.517±0.141 mm vs. 0.467±0.099 mm, P=0.073). In the correlation analysis, the CIMT was found to be correlated negatively with FMD and positively with high sensitive C-reactive protein, VWF-Ag, and D-dimer. CONCLUSIONS These findings suggest that VWF-Ag and D-dimer can be beneficial early atherosclerosis markers in IBD patients.

The metabolic syndrome: an emerging risk state for cardiovascular disease

The common clustering of glucose intolerance, insulin resistance, abdominal adiposity, elevated blood pressure, and low HDL cholesterol is referred to as metabolic syndrome. Individuals with this syndrome have an increased risk of developing cardiovascular disease (CVD). The World Health Organisation and the National Cholesterol Education Programme’s Adult Treatment Panel III (NCEP-ATP III) have outlined specific diagnostic criteria for the diagnosis of the metabolic syndrome to help in the Identification of this syndrome in clinical practice. While the WHO criteria were specifically developed for use in research, the NCEP criteria are useful in clinical diagnosis of the metabolic syndrome. The metabolic syndrome is amenable to lifestyle modifications such as increased physical activity, weight loss, and possibly intake of low-glycemic foods. Drug therapy may be used to treat individual components of the syndrome such as elevated blood pressure and dyslipidemia. To control elevated glucose levels (when there is failure of lifestyle modification), medications such as metformin, thiazolidinedione derivatives and alpha glucosidase inhibitors may be used.

Evaluation of Serum Pregnancy Associated Plasma Protein-A & Plasma D-Dimer in Acute Coronary Syndrome

INTRODUCTION

Acute coronary syndrome (ACS), a spectrum comprising unstable angina pectoris, ST Elevated Myocardial Infarction (STEMI) & Non ST Elevated Myocardial Infarction (NSTEMI) is the major cause of presentation in Emergency Department today. Though ECG and cardiac enzymes are used for diagnosis, they mislead the diagnosis sometimes and delay in treatment initiation. This leads us to search certain new parameters which reflect the pathophysiology of ACS. Markers of plaque stability like Pregnancy Associated Plasma Protein-A and D-Dimer, a marker of ongoing thrombosis are found to be better markers in early diagnosis.

AIM

To evaluate the diagnostic competence of PAPP-A and D-Dimer in acute coronary syndrome over CK-MB and to compare with the inflammatory marker High Sensitive C-Reactive Protein (hs-CRP) which is associated with atherosclerosis.

MATERIALS AND METHODS

Fifty patients presenting with acute onset of chest pain to Emergency Department with or without ECG changes served as cases and 50 healthy people served as controls. Serum PAPP-A is measured by Enzyme Linked Immunosorbent Assay (ELISA), D-Dimer and hs-CRP by using Latex Turbidimetry method.

RESULTS

A statistical significant difference of PAPP-A and D-Dimer was noted between the ACS and controls (p < 0.001) whereas CK-MB shows no much difference (p 0.09). Statistically significant positive correlation is noted between parameters.

CONCLUSION

PAPP-A marker of plaque instability and D-Dimer marker of ongoing thrombosis are raised in acute coronary syndrome and thus can be considered as one of the marker in ACS for diagnosis.

Plasma d-Dimer and Incident Ischemic Stroke and Coronary Heart Disease: The Atherosclerosis Risk in Communities Study

BACKGROUND AND PURPOSE

Epidemiological studies have documented that plasma d-dimer, a fibrin degradation product, is a risk marker for coronary heart disease, but there is limited prospective evidence for stroke. Given that thrombosis is a key mechanism for many strokes, we studied whether d-dimer is a risk marker for ischemic stroke incidence in the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

We measured d-dimer in 11 415 ARIC participants free of stroke and coronary heart disease in 1992 to 1995. We followed them for stroke, stroke subtype, and coronary heart disease events through 2012.

RESULTS

Over a median of 18 years of follow-up, 719 participants had incident strokes (628 ischemic and 91 hemorrhagic). d-dimer was associated positively with risk of total, ischemic, and cardioembolic strokes, with risk elevated primarily for the highest quintile of d-dimer. After adjustment for other cardiovascular risk factors, the hazard ratio for the highest versus lowest quintile of d-dimer was 1.30 (95% confidence interval, 1.02-1.67) for total stroke, 1.33 (95% confidence interval, 1.02-1.73) for ischemic stroke, and 1.79 (95% confidence interval, 1.08-2.95) for cardioembolic stroke. There was no association with hemorrhagic, lacunar, or nonlacunar stroke categories. d-dimer was positively but weakly associated with coronary heart disease incidence.

CONCLUSIONS

A higher basal plasma d-dimer concentration in the general population is a risk marker for ischemic stroke, especially cardioembolic stroke.

Differential cellular effects of old and new oral anticoagulants: consequences to the genesis and progression of atherosclerosis

The main purpose of anticoagulants is to diminish fibrin formation, thereby decreasing the risk of venous or arterial thrombosis. Vitamin K antagonist have been used for many decades in order to achieve reduced thrombotic risk, despite major drawbacks of this class of drugs such as cumbersome dossing and monitoring of anticoagulant status. To overcome these drawbacks of VKA, new classes of anticoagulants have been developed including oral anticoagulants for direct inhibition of either thrombin or factor Xa, which can be administrated in a fixed dose without monitoring. Coagulation factors can activate cellular protease-activated receptors, thereby inducing cellular processes as inflammation, apoptosis, migration, and fibrosis. Therefore, inhibition of coagulation proteases not only attenuates fibrin formation, but may also influence pathophysiological processes like vascular calcification and atherosclerosis. Animal models revealed that VKA therapy induced both intima and media calcification and accelerated plaque vulnerability, whereas specific and direct inhibition of thrombin or factor Xa attenuated atherosclerosis. In this review we provide an overview of old and new oral anticoagulants, as well discuss potential pleiotropic effects with regard to calcification and atherosclerosis. Although translation from animal model to clinical patients seems difficult at first sight, effort should be made to fully understand the clinical implications of long-term oral anticoagulant therapy on vascular side effects.

Profibrinolytic effect of the epigenetic modifier valproic acid in man

AIMS

The aim of the study was to test if pharmacological intervention by valproic acid (VPA) treatment can modulate the fibrinolytic system in man, by means of increased acute release capacity of tissue plasminogen activator (t-PA) as well as an altered t-PA/Plasminogen activator inhibitor -1 (PAI-1) balance. Recent data from in vitro research demonstrate that the fibrinolytic system is epigenetically regulated mainly by histone deacetylase (HDAC) inhibitors. HDAC inhibitors, including VPA markedly upregulate t-PA gene expression in vitro.

METHODS AND RESULTS

The trial had a cross-over design where healthy men (n = 10), were treated with VPA (Ergenyl Retard) 500 mg depot tablets twice daily for 2 weeks. Capacity for stimulated t-PA release was assessed in the perfused-forearm model using intra-brachial Substance P infusion and venous occlusion plethysmography. Each subject was investigated twice, untreated and after VPA treatment, with 5 weeks wash-out in-between. VPA treatment resulted in considerably decreased levels of circulating PAI-1 antigen from 22.2 (4.6) to 10.8 (2.1) ng/ml (p<0.05). It slightly decreased the levels of circulating venous t-PA antigen (p<0.05), and the t-PA:PAI-1 antigen ratio increased (p<0.01). Substance P infusion resulted in an increase in forearm blood flow (FBF) on both occasions (p<0.0001 for both). The acute t-PA release in response to Substance P was not affected by VPA (p = ns).

CONCLUSION

Valproic acid treatment lowers plasma PAI-1 antigen levels and changes the fibrinolytic balance measured as t-PA/PAI-1 ratio in a profibrinolytic direction. This may in part explain the reduction in incidence of myocardial infarctions by VPA treatment observed in recent pharmacoepidemiological studies.

TRIAL REGISTRATION

The EU Clinical Trials Register 2009-011723-31.

Biotechnology and genetic engineering in the new drug development. Part I. DNA technology and recombinant proteins

Pharmaceutical biotechnology has a long tradition and is rooted in the last century, first exemplified by penicillin and streptomycin as low molecular weight biosynthetic compounds. Today, pharmaceutical biotechnology still has its fundamentals in fermentation and bioprocessing, but the paradigmatic change affected by biotechnology and pharmaceutical sciences has led to an updated definition. The biotechnology revolution redrew the research, development, production and even marketing processes of drugs. Powerful new instruments and biotechnology related scientific disciplines (genomics, proteomics) make it possible to examine and exploit the behavior of proteins and molecules. Recombinant DNA (rDNA) technologies (genetic, protein, and metabolic engineering) allow the production of a wide range of peptides, proteins, and biochemicals from naturally nonproducing cells. This technology, now approximately 25 years old, is becoming one of the most important technologies developed in the 20(th) century. Pharmaceutical products and industrial enzymes were the first biotech products on the world market made by means of rDNA. Despite important advances regarding rDNA applications in mammalian cells, yeasts still represent attractive hosts for the production of heterologous proteins. In this review we describe these processes.

Relationship of coagulation and fibrinolytic variables with arterial structure and function in Africans

INTRODUCTION

Although both coagulation and fibrinolysis are associated with cardiovascular disease (CVD) the underlying nature and pathways of many of these associations are still unclear. Our aim was to determine which of the current or 5-year prior levels of total fibrinogen, fibrinogen γ', plasminogen activator inhibitor-1 (PAI-1act) and global fibrinolytic potential were the stronger determinant of arterial structure and function.

MATERIALS AND METHODS

This prospective study consisted of 2010 Africans over the age of 35 years with 5-year follow-up data available for 1288 participants. Cardiovascular measurements included arterial stiffness, blood pressure and carotid intima media thickness.

RESULTS

Fibrinogen γ' showed stronger associations with blood pressure than total fibrinogen also in the presence of other CVD risk factors. PAI-1act was positively associated with blood pressure both cross-sectionally and prospectively, with the longitudinal association being the stronger determinant, also after adjustment for known CVD risk factors. Clot lysis time (CLT) was positively associated, both prospectively and cross-sectionally, with intima media thickness and negatively with markers of arterial stiffness but not after adjustment for known CVD risk factors.

CONCLUSIONS

Fibrinogen γ' was more strongly associated with CVD function than total fibrinogen. PAI-1act was significantly associated with blood pressure with changes in PAI-1 levels preceding changes in blood pressure. Different mechanisms may be at play determining arterial wall stiffness/thickening and blood pressure as observed from the opposing associations with PAI-1act and CLT. CLT was not independently related to cardiovascular measures as its associations were weakened in the presence of other known CVD risk factors.

Age and aerobic training status effects on plasma and skeletal muscle tPA and PAI-1

INTRODUCTION

Reductions in fibrinolytic potential occur with both aging and physical inactivity and are associated with an increased cardiovascular disease risk. Plasmin, the enzyme responsible for the enzymatic degradation of fibrin clots, is activated by tissue plasminogen activator (tPA), while plasminogen activator inhibitor-1 (PAI-1) inhibits its activation. Currently, fibrinolysis research focuses almost exclusively on changes within the plasma. However, tPA and PAI-1 are expressed by human skeletal muscle (SM). Currently, no studies have focused on changes in SM fibrinolytic activity with regard to aging and aerobic fitness.

PURPOSE

The purpose of this study was to cross-sectionally evaluate effects of age and aerobic fitness on tPA and PAI-1 expressions and activity in SM.

METHODS

Twenty-six male subjects were categorized into the following groups: (1) young aerobically trained (n = 8); (2) older aerobically trained (n = 6); (3) young aerobically untrained (n = 7); and (4) older aerobically untrained (n = 5). Muscle biopsies were obtained from each subject. SM tPA activity was assessed using gel zymography and SM tPA and PAI-1 expressions were assessed using RT-PCR.

RESULTS

Trained subjects had higher SM tPA activity compared to untrained (25.3 ± 2.4 × 10(3) vs. 21.5 ± 5.6 × 10(3) pixels, respectively; p = 0.03) with no effect observed for age. VO2 max and SM tPA activity were also significantly correlated (r = 0.42; p < 0.04). SM tPA expression was higher in older participants, but no effect of fitness level was observed. No differences were observed for PAI-1 expression in SM.

CONCLUSIONS

Higher levels of aerobic fitness are associated with increased fibrinolytic activity in SM.

[Assessment of endothelial function in autoimmune diseases]

Numerous autoimmune-inflammatory rheumatic diseases have been associated with accelerated atherosclerosis or other types of vasculopathy leading to an increase in cardiovascular disease incidence. In addition to traditional cardiovascular risk factors, endothelial dysfunction is an important early event in the pathogenesis of atherosclerosis, contributing to plaque initiation and progression. Endothelial dysfunction is characterized by a shift of the actions of the endothelium toward reduced vasodilation, a proinflammatory and a proadhesive state, and prothrombic properties. Therefore, assessment of endothelial dysfunction targets this vascular phenotype using several biological markers as indicators of endothelial dysfunction. Measurements of soluble adhesion molecules (ICAM-1, VCAM-1, E-selectin), pro-thrombotic factors (thrombomodulin, von Willebrand factor, plasminogen activator inhibitor-1) and inflammatory cytokines are most often performed. Regarding the functional assessment of the endothelium, the flow-mediated dilatation of conduit arteries is a non-invasive method widely used in pathophysiological and interventional studies. In this review, we will briefly review the most relevant information upon endothelial dysfunction mechanisms and explorations. We will summarize the similarities and differences in the biological and functional assessments of the endothelium in different autoimmune diseases.

Plasminogen activator inhibitor-1 inhibitors: a patent review (2006-present)

INTRODUCTION

Plasminogen activator inhibitor-1 (PAI-1), the serine protease inhibitor (serpin), binds to and inhibits the plasminogen activators-tissue-type plasminogen activator (tPA) and the urokinase-type plasminogen activator (uPA). This results in both a decrease in plasmin production and a decrease in the dissolution of fibrin clots. Elevated levels of PAI-1 are correlated with an increased risk for cardiovascular disease and have been linked to obesity and metabolic syndrome. Consequently, the pharmacological suppression of PAI-1 might prevent or treat vascular disease.

AREAS COVERED

This article provides an overview of the patenting activity on PAI-1 inhibitors. Patents filed by pharmaceutical companies or individual research groups are described, and the biological and biochemical evaluation of the inhibitors, including in vitro and in vivo studies, is discussed. An overview of patents pertaining to using these inhibitors for treating various diseases is also included.

EXPERT OPINION

Although there is still no PAI-1 inhibitor being evaluated in a clinical setting or approved for human therapy, research in this field has progressed, and promising new compounds have been designed. Most research has focused on improving the pharmacological profile of these compounds, which will hopefully allow them to proceed to clinical studies. Despite the need for further testing and research, the potential use of PAI-1 inhibitors for treating cardiovascular disease appears quite promising.

Beyond fibrinolysis: the role of plasminogen activator inhibitor-1 and vitronectin in vascular wound healing

Plasminogen activator inhibitor-1 (PAI-1), as the name implies, is the primary in vivo inhibitor of both tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA). PAI-1 also binds to other nonproteinase ligands, including the matrix protein vitronectin, glycosaminoglycans such as heparin, and the endocytic clearance receptor, the low-density-lipoprotein-receptor-related protein (LRP). PAI-1 belongs to the superfamily of serine proteinase inhibitors (serpins), and, like other serpins, it acts as "suicide inhibitor" that reacts only once with a target proteinase. The suicide mechanism results in irreversible modification of the serpin and an extensive change in its conformation. In the case of PAI-1, this conformational change is important not only for inhibition of the proteinase, but it also causes changes in affinity for vitronectin and LRP. These changes have important consequences for cell migration.

The impact of blood coagulability on atherosclerosis and cardiovascular disease

Although the link between blood coagulation and atherogenesis has been long postulated, only recently, and through the extensive work on transgenic mice, crossbred on an atherogenic background, has the direction of this interaction become visible. In general, hypercoagulability in mice tends to increase atherosclerosis, whereas hypocoagulability reduces the atherosclerotic burden, depending on the mouse model used. The information on a direct relationship between coagulation and atherosclerosis in humans, however, is not that clear. Almost all coagulation proteins, including tissue factor, are found in atherosclerotic lesions in humans. In addition to producing local fibrin, a matrix for cell growth, serine proteases such as thrombin may be very important in cell signaling processes, acting through the activation of protease-activated receptors (PARs). Activation of PARs on vascular cells drives many complex processes involved in the development and progression of atherosclerosis, including inflammation, angiogenesis, and cell proliferation. Although current imaging techniques do not allow for a detailed analysis of atherosclerotic lesion phenotype, hypercoagulability, defined either by gene defects of coagulation proteins or elevated levels of circulating markers of activated coagulation, has been linked to atherosclerosis-related ischemic arterial disease. New, high-resolution imaging techniques and sensitive markers of activated coagulation are needed in order to study a causal contribution of hypercoagulability to the pathophysiology of atherosclerosis. Novel selective inhibitors of coagulation enzymes potentially have vascular effects, including inhibition of atherogenesis through attenuation of inflammatory pathways. Therefore, we propose that studying the long-term vascular side effects of this novel class of oral anticoagulants should become a clinical research priority.

Exposure of endothelial cells to physiological levels of myeloperoxidase-modified LDL delays pericellular fibrinolysis

BACKGROUND

Blood fluidity is maintained by a delicate balance between coagulation and fibrinolysis. The endothelial cell surface is a key player in this equilibrium and cell surface disruptions can upset the balance. We investigated the role of pericellular myeloperoxidase oxidized LDLs (Mox-LDLs) in this balance.

METHODS AND RESULTS

We designed a technical device that enabled us to monitor fibrinolysis in real-time at the surface of an endothelial cell line (EA.hy926), and showed that Mox-LDL decreased pericellular fibrinolysis. There were no changes in fibrinolysis when EA.hy926 endothelial cells were exposed to native LDL (24 hours) at doses of 10, 50, 100 and up to 1250 µg/ml. However, treatment of EA.hy926 endothelial cells with 10 and 50 µg/ml of Mox-LDL (physiological serum concentrations) increased the lysis time by 15 and 13%, respectively (p<0.001), although this effect was not present at higher concentrations of 100 µg/ml. This effect was not correlated with any changes in PAI-1 or t-PA or PA Receptor (PAR) expression. No effect was observed at the surface of smooth muscle cells used as controls.

CONCLUSION

Our data link the current favorite hypothesis that modified LDL has a causal role in atheroma plaque formation with an old suggestion that fibrin may also play a causal role. Our data help complete the paradigm of atherosclerosis: Modified LDL locally enhances fibrin deposition (present work); fibrin deposits enhance endothelial permeability; this effect allows subendothelial accumulation of lipid and foam cells.

Pentoxifylline Lowers Plasminogen Activator Inhibitor 1 Levels in Obese Individuals: A Pilot Study

Plasminogen activator inhibitor 1 (PAI-1), the primary inhibitor of fibrinolysis and C-reactive protein (CRP), is a predictor of myocardial infarction. Both are upregulated by tumor necrosis factor-alpha (TNF-α) within the obese population. This pilot study tested the hypothesis that TNF-α blockade with pentoxifylline lowers PAI-1 and high-sensitivity CRP (hsCRP) in obese individuals. Twenty participants were treated with pentoxifylline for 8 weeks. A proportional odds model was used to compare the change in PAI-1 and CRP in the pentoxifylline and placebo groups. Plasminogen activator inhibitor 1, but not hsCRP levels, decreased over the 8-week period of the study ( P = .025 and P = NS). There was significant dropout of participants due to drug tolerability. These findings suggest that these markers of cardiovascular risk are differentially regulated in obesity and that PAI-1 levels can be reduced by pentoxifylline in this population.

Role of fibrinolytic parameters and plasminogen activator inhibitor 1 (PAI-1) promoter polymorphism on premature atherosclerosis in SLE patients

Premature atherosclerosis has been recognized as a major co-morbid condition in systemic lupus erythematosus (SLE). In this study, we aimed to investigate the effect of tPA (tissue plasminogen activator) and PAI-1 (plasminogen activator inhibitor) antigen concentrations and 4G/5G polymorphism of the PAI-1 gene on the development of atherosclerosis in SLE patients. One hundred and six SLE patients, 28 Takayasu arteritis (TA) patients and 98 healthy control subjects (HCs) were studied. PAI-1 and tPA antigen levels were measured by ELISA method. PAI-1 gene polymorphism was determined by using allele-specific PCR method. SLE patients had a significantly higher frequency (22.6%) of plaque (p = 0.01) and higher IMT (p=0.04) compared with HCs respectively. Only age at disease onset was associated with plaque formation in multivariate regression analysis (p = 0.001). Plasma tPA ag levels in SLE patients were significantly higher compared with HCs (p = 0.005) and PAI-1 ag levels were significantly higher compared with TA patients (p = 0.03). There were no significant differences between study groups in both genotype distribution and allele frequencies of PAI-1 gene, but SLE patients with 4G/4G genotype had higher IMT (p = 0.02) calcium scoring (p = 0.006) compared with 4G5G/5G5G genotypes. The present study suggests that measuring fibrinolytic parameters would have little additional benefit beyond traditional and novel risk factors in predicting coronary artery disease (CAD).

Associations of D-dimer and von Willebrand factor with atherosclerosis in Japanese and white men

OBJECTIVE

D-dimer and von Willebrand factor (vWF) are associated with atherosclerosis. We recently reported that in a post-World War II birth cohort, Japanese men in Japan had lower levels of atherosclerosis than white men in the United States (U.S.). We examined whether the differences in D-dimer and vWF levels are associated with differences in atherosclerosis between the two populations.

METHODS AND RESULTS

Population-based samples of 99 Japanese and 100 white American men aged 40-49 years were examined for coronary artery calcification (CAC), carotid intima-media thickness (IMT), D-dimer, vWF, and other factors using a standardized protocol. When compared to white American men,Japanese had similar levels of D-dimer (0.22 +/- 0.28 vs. 0.19 +/- 0.24 microg/L, respectively, P = 0.39) but significantly higher levels of vWF (124.1 +/- 36.6 vs. 91.3 +/- 48.8%, respectively, P < 0.01). Japanese as compared to white American men had significantly lower prevalence of CAC (13.1 vs. 28.0%, P < 0.01, respectively) and significantly lower IMT (0.61 +/- 0.07 vs. 0.66 +/- 0.08 mm, P < 0.01, respectively). Japanese men had a significant positive association of D-dimer with the prevalence of CAC and a negative association of vWF with IMT, whereas white American men did not have any significant associations.

CONCLUSIONS

In men aged 40-49 years, Japanese as compared to white Americans had similar levels of D-dimer and higher levels of vWF although Japanese had a significantly lower prevalence of CAC and IMT. These haemostatic factors are unlikely to explain the difference in atherosclerosis in these populations.

Arterial stiffness is strongly associated with insulin resistance in Chinese--a population-based study (Taichung Community Health Study, TCHS)

AIM

Few studies have investigated the association between insulin resistance and arterial stiffness in Chinese. We aimed to investigate this relationship in a population-based study of middle-aged Chinese.

METHODS

A total of 2,188 subjects aged 40 years and older were recruited in 2004 in Taiwan. The association between arterial stiffness (measured by brachial-ankle pulse wave velocity (baPWV)) and insulin resistance (represented by homeostasis model assessment (HOMA-IR) and fasting glucose levels) was studied by multiple logistic and linear regression analyses.

RESULTS

The respective prevalence of diabetes and impaired fasting glucose (IFG) was 13.9% and 30.6% in males and 10.4% and 20.8% in females. Using multiple linear regression analyses, we found baPWV to be strongly associated with age, gender, body mass index (BMI), waist circumference (WC), systolic blood pressure (BP), diastolic BP, fasting glucose, and triglycerides. Compared to the lowest HOMA-IR tertile I and adjusting for age, BMI, WC, gender, triglycerides, systolic BP, diastolic BP, smoking, alcohol drinking, betel nut chewing, and physical activity, the odds ratios (95% confidence interval) of arterial stiffness for the higher HOMA-IR tertiles II and III were 1.15 (0.77-1.71) and 1.60 (1.05-2.46), respectively. Using a general linear model with adjustment for age, systolic BP, diastolic BP, BMI, WC, and triglycerides, baPWV was significantly lower in the diabetic group by 90.3 cm/sec in males and 100.5 cm/sec in females compared to the IFG group. When comparing the IFG group to the normal glucose group, baPWV was 28.5 cm/sec lower in males and 14.4 cm/sec lower in females.

CONCLUSIONS

Arterial stiffness is independently associated with insulin resistance in Chinese middle-aged adults. Subjects with diabetes or IFG have higher baPWV than normoglycemic subjects.

[Acute myocardial infarction in young smokers treated by coronary angioplasty. In-hospital prognosis and long-term outcome in a consecutive series of 93 patients]

AIMS OF THE STUDY

The study evaluated in-hospital and long-term outcome of patients less than 50 years old with myocardial infarction within 12 hours after symptom onset treated by coronary angioplasty.

PATIENTS AND METHOD

This is a retrospective study with survival analysis by Kaplan-Meier method in patients included from December 2003 to February 2008.

RESULTS

We included 93 patients aged 42,8+/-5,2 years old with smoking estimated at 27,7+/-12,7 pack-years. Thirty-one patients (33,3%) were dyslipidemic and 36 patients had family history of coronary artery disease. Thirty patients (32,3%) had an anterior myocardial infarction and four patients (4.4%) had Killip greater than 2. Coronary angioplasty was performed within 4.5+/-3.0 hours after symptom onset with TIMI 3 final flow in the culprit vessel in 96.8%. One patient died from cardiogenic shock. With a follow-up of 85 patients during 20.0+/-15.6 months, the survival without death was 98.2% and survival without major cardiac complication was 87.9% at 24 months. Seventy-two patients (85.7%) were taking a betablocker, 81 patients (96.4%) aspirin, 75 patients (89.3%) a statin and 64 patients (76.2%) an angiotensin-converting inhibitor. Only 50 patients (58.8%) were nonsmokers.

CONCLUSION

Thus, young smokers with acute MI treated by coronary angioplasty have a good prognosis during in-hospital stay and long-term outcome. Secondary medical treatment prevention is well followed but there is a low rate of smoking cessation.

Endothelial dysfunction in diabetes: potential application of circulating markers as advanced diagnostic and prognostic tools

Endothelial dysfunction is a predisposing factor for vascular disease in diabetes, which contributes significantly to the mortality of diabetic patients. The currently utilized assessment methods of endothelial function/dysfunction in humans are associated with various limitations. Circulating endothelial-derived/associated markers have been proposed as potential alternatives for evaluation of the endothelium in condition of vascular disorders. These indicators include von Willebrand factor, soluble thrombomodulin, soluble E-selectin, asymmetric dimethylarginine, tissue plasminogen activator, endothelial microparticles, circulating endothelial cells and circulating endothelial progenitor cells. While tentative evidence is available for most of these biomarkers to serve as reliable sources of information, their usefulness for routine clinical applications has not yet been established. Thus, circulating endothelial markers are currently the subject of intense research interest and it is anticipated that as more information becomes available their improved quantification will provide a suitable diagnostic and prognostic tool for vascular events in diabetes and related diseases.

Effect on the atherogenic marker plasminogen activator inhibitor type-1 of addition of the ACE inhibitor imidapril to angiotensin II type 1 receptor antagonist therapy in hypertensive patients with abnormal glucose metabolism: a prospective cohort study in primary care

BACKGROUND AND OBJECTIVE

Renin-angiotensin system (RAS) inhibitors, such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]), are recommended by the American Diabetes Association for blood pressure control and prevention or management of cardiovascular disease in patients with diabetes mellitus. However, some investigators have suggested that ARBs may increase the risk of myocardial infarction in hypertensive patients. Activation of the RAS is associated with an increased risk of ischaemic events. Angiotensin II stimulates the production of plasminogen activator inhibitor type-1 (PAI-1), a powerful predictor of cardiovascular disease. ACE inhibitors are reported to reduce PAI-1 levels and activity, while ARBs do not reduce or may even elevate levels of this atherogenic marker. The objective of this study was to determine whether the ACE inhibitor imidapril reduces PAI-1 levels in hypertensive patients already being treated with an ARB.

METHODS

This was a prospective cohort study carried out in primary care with a follow-up period of 6 months. Estimating the alpha error (p-value) at 0.05, the power of the test as 80%, and the difference in PAI-1 levels as 10 + or - 15 ng/mL, the required sample size was calculated to be 40. Participants were hypertensive patients taking ARBs for more than 8 weeks, and having dyslipidaemia, obesity or abnormal glucose metabolism. Imidapril 5-10 mg/day was prescribed for 6 months to reduce blood pressure to <130/80 mmHg. The main outcome measure, PAI-1 level, was measured before and 6 months after the addition of imidapril to ARBs in 21 subjects (13 men, eight women), all with abnormal glucose metabolism, nine with dyslipidaemia, and six who were obese. Bodyweight, body mass index, blood pressure, homeostasis model assessment of insulin resistance, glycosylated haemoglobin, creatinine, potassium, high sensitivity C-reactive protein (hs-CRP), and high molecular weight adiponectin levels were measured as secondary outcomes.

RESULTS

PAI-1 level was not significantly changed overall. Hs-CRP level was also not significantly changed; however, the high molecular weight adiponectin level was significantly increased (p = 0.044), especially in men (p = 0.026). There were no significant changes in the other outcomes measured.

CONCLUSION

The current study showed that imidapril added to ARBs did not decrease PAI-1 levels in hypertensive patients with abnormal glucose metabolism; however, this combination therapy significantly increased high molecular weight adiponectin levels in men.

Plasminogen activator inhibitor-1 is associated with coronary artery calcium in Type 1 diabetes

BACKGROUND

Elevated levels of plasminogen activator inhibitor-1 (PAI-1), the major inhibitor of fibrinolysis, is associated with coronary artery disease (CAD). This association may not be independent of factors related to insulin resistance (IR). Patients with Type 1 diabetes mellitus have increased CAD and an increase in sub-clinical CAD which develops earlier in life. It is not known if PAI-1 is associated with sub-clinical CAD in Type 1 diabetes or if this association is independent of IR.

METHODS AND RESULTS

Type 1 diabetes patients (n=560) and participants without diabetes (n=693) were assessed for coronary artery calcium (CAC), a surrogate for subclinical CAD, by electron-beam computed tomography. PAI-1 was associated with CAC in both Type 1 diabetes (OR=1.32, 95% CI=1.12-1.58) and non-diabetes (OR=1.34, 95% CI=1.13-1.58), after controlling for traditional risk factors not associated with IR. In Type 1 diabetes, the relationship between PAI-1 and CAC was strongest for younger participants (P=.02 for PAI-1-by-age interaction) after controlling for factors related to IR. PAI-1 was positively associated with CAC for Type 1 diabetes participants younger than 45 years of age.

CONCLUSION

PAI-1 levels are independently related to CAC in younger Type 1 diabetes participants. PAI-1 levels were not independently related to CAC in non-diabetes participants.

Hemostatic factors and subclinical brain infarction in a community-based sample: the ARIC study

BACKGROUND

Previous data are conflicting as to whether imbalance between hemostatic factors is associated with clinical strokes. We evaluated the association between hemostatic factor levels and subclinical lacunar infarcts in a nested sample from a subset of the Atherosclerosis Risk in Communities (ARIC) cohort.

METHODS

196 cases without clinical strokes had lacunar infarcts by MRI, and 214 controls without radiographic infarcts were frequency-matched by age group and sex. Logistic regression models were fitted to assess the association between levels of hemostatic markers and case status.

RESULTS

In age-, race- and sex-adjusted models, von Willebrand factor (vWF) and D-dimer were positively associated with case status, with odds ratios for the highest vs. lowest tertile of 2.0 (95% CI 1.2-3.6) for vWF and 1.76 (95% CI 1.02-3.0) for D-dimer. Plasminogen had nonsignificant inverse associations with presence of silent lacunar infarcts.

CONCLUSIONS

vWF and D-dimer were positively associated, and plasminogen was nonsignificantly inversely associated with subclinical radiographic infarct. Further studies on the role of these hemostatic factors in the development of silent lacunar infarcts may help elucidate the mechanisms behind this injury and may even point to potential targets for future intervention.

Multimarker approach to evaluate correlates of vascular stiffness: the Framingham Heart Study

BACKGROUND

Arterial stiffness increases with age and contributes to the pathogenesis of systolic hypertension and cardiovascular disease in the elderly. Knowledge about the pathophysiological processes that determine arterial stiffness may help guide therapeutic approaches.

METHODS AND RESULTS

We related 7 circulating biomarkers representing distinct biological pathways (C-reactive protein, aldosterone-to-renin ratio, N-terminal proatrial natriuretic peptide and B-type natriuretic peptide, plasminogen activator inhibitor-1, fibrinogen, and homocysteine) to 5 vascular function measures (central pulse pressure, carotid-femoral pulse-wave velocity, mean arterial pressure, forward pressure wave amplitude [all measures of conduit artery stiffness], and augmented pressure, an indicator of wave reflection) in 2000 Framingham Offspring Study participants (mean age, 61 years; 55% women). Tonometry measures were obtained on average 3 years after the biomarkers were measured. In multivariable linear regression models adjusting for covariates, the biomarker panel was significantly associated with all 5 vascular measures (P<0.003 for all). On backward elimination, the aldosterone-to-renin ratio was positively associated with each stiffness measure (P< or =0.002 for all). In addition, C-reactive protein was positively related to augmented pressure (P=0.0003), whereas plasminogen activator inhibitor-1 was positively associated with mean arterial pressure (P=0.003), central pulse pressure (P=0.001), and forward pressure wave (P=0.01).

CONCLUSIONS

Our cross-sectional data on a community-based sample suggest a distinctive pattern of positive associations of biomarkers of renin-angiotensin-aldosterone system activation with pan-arterial vascular stiffness, plasminogen activator inhibitor-1 with central vascular stiffness indices, and C-reactive protein with wave reflection. These observations support the notion of differential influences of biological pathways on vascular stiffness measures.

Male-female differences in the genetic regulation of t-PA and PAI-1 levels in a Ghanaian population

Tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) directly influence thrombus formation and degradation, and have been identified as risk factors for thromboembolic disease. Prior studies investigated determinants of t-PA and PAI-1 expression, but mainly in Caucasian subjects. The aim of this study was to identify the contributions of genetic and other factors to inter-individual variation in plasma levels of t-PA and PAI-1 in a large-scale population-based sample from urban West Africa. t-PA, PAI-1 and several demographic, anthropometric, and metabolic parameters were measured in 992 residents of Sunyani, the capital of the Brong-Ahafo region of Ghana. In addition, nine gene polymorphisms associated with components of the renin-angiotensin and fibrinolytic systems were determined. We found that BMI, systolic and diastolic blood pressure, total cholesterol, glucose, and triglycerides were all significant predictors of t-PA and PAI-1 in both females and males. In addition, a significant relationship was found between the PAI-1 4G/5G (rs1799768) polymorphism on PAI-1 levels in females, the TPA I/D (rs4646972) polymorphism on t-PA and PAI-1 in males, the renin (rs3730103) polymorphism on t-PA and PAI-1 in males, the ethanolamine kinase 2 (rs1917542) polymorphism on PAI-1 in males, and the renin (rs1464816) polymorphism on t-PA in females and on PAI-1 in males. This study of urban West Africans shows that t-PA and PAI-1 levels are determined by both genetic loci of the fibrinolytic and renin-angiotensin systems and other factors often associated with cardiovascular disease, and that genetic factors differ between males and females.