High levels of tissue plasminogen activator (tPA) antigen precede the development of type 2 diabetes in a longitudinal population study. The Northern Sweden MONICA study

Assays to quantify fibrinolysis: strengths and limitations. Communication from the International Society on Thrombosis and Haemostasis Scientific and Standardization Committee on fibrinolysis

Fibrinolysis is a series of enzymatic reactions that degrade insoluble fibrin. Plasminogen activators convert the zymogen plasminogen to the active serine protease plasmin, which cleaves and solubilizes crosslinked fibrin clots into fibrin degradation products. The quantity and quality of fibrinolytic enzymes, their respective inhibitors, and clot structure determine overall fibrinolysis. The quantity of protein can be measured by antigen-based assays, and both quantity and quality can be assessed using functional assays. Furthermore, variations of commonly used assays have been reported, which are tailored to address the role(s) of specific fibrinolytic factors and cellular elements (eg, platelets, neutrophils, and red blood cells). Although the concentration and/or activity of a protein can be quantified, how these individual components contribute to the overall fibrinolysis outcome can be challenging to determine. This difficulty is due to temporal changes within and around the thrombi during the clot breakdown, particularly the fibrin matrix structure, and composition. Furthermore, terms such as "fibrinolytic activity/potential," "plasminogen activation," and "plasmin activity" are often used interchangeably despite having different definitions. The purpose of this review is to 1) summarize the assays measuring fibrinolysis activity and potential, 2) facilitate the interpretation of data generated by these assays, and 3) summarize the strengths and limitations of these assays.

Correlations between the Changing Levels of Tissue Plasminogen Activator and Adiposity Following Exercise-Induced Weight Loss

Cardiovascular disease is a major threat to global public health. Tissue plasminogen activator (TPA) is a serine protease that dissolves blood clots, which can also lead to excessive bleeding. Fibrinogen (FIBR), a glycoprotein, is converted by thrombin to fibrin and then to a fibrin-based blood clot. Both TPA and FIBR levels in the blood are associated with an increased risk of coronary heart disease, and the levels of the two factors are also positively correlated with total adipose tissue amounts. Visceral and subcutaneous adipose tissues (VAT and SAT) can contribute differently to whole-body metabolism. In this study, we sought to assess: (1) the strength of the correlation between the changing levels of the two factors and the changing amounts of VAT/SAT during exercise-induced weight loss, (2) whether there is any difference between the two types of adipose tissues in terms of the correlation, and (3) which factor, TPA or FIBR, is more sensitive to changes in adiposity? For this study, we analyzed the data from the diabetes prevention program (DPP), in which the participants were divided into three groups, with one group undergoing a lifestyle change that involved maintaining a minimum of 7% weight loss with physical activity. We found that the basal amounts of VAT and SAT were correlated with TPA and FIBR levels. However, following weight loss, adiposity changes were strongly correlated with the changing levels of TPA, but not FIBR, for both men and women. Therefore, TPA, but not FIBR, is sensitive to changes in adiposity. Furthermore, regarding TPA, weight loss sensitized its correlation with SAT, but not VAT. This study shows how adipose tissues distinctively affect TPA and FIBR levels, two factors associated with cardiovascular disease and ischemic stroke.

A Starch- and Sucrose-Reduced Diet in Irritable Bowel Syndrome Leads to Lower Circulating Levels of PAI-1 and Visfatin: A Randomized Controlled Study

Irritable bowel syndrome (IBS) is characterized by gastrointestinal symptoms. Overweight and increased risk of metabolic syndromes/diabetes are observed in IBS, conditions associated with plasminogen activator inhibitor-1 (PAI-1) and visfatin. The aim of this study was to measure blood levels of AXIN1, cholecystokinin (CCK), enkephalin, ghrelin, neuropeptide Y (NPY), PAI-1, and visfatin before and after a 4-week intervention with a starch- and sucrose-reduced diet (SSRD). A total of 105 IBS patients were randomized to either SSRD (n = 80) or ordinary diet (n = 25). Questionnaires were completed, and blood was analyzed for AXIN1 and hormones. AXIN1 (p = 0.001) and active ghrelin levels (p = 0.025) were lower in IBS than in healthy volunteers at baseline, whereas CCK and enkephalin levels were higher (p < 0.001). In the intervention group, total IBS-symptom severity score (IBS-SSS), specific gastrointestinal symptoms, psychological well-being, and the influence of intestinal symptoms on daily life were improved during the study, and weight decreased (p < 0.001 for all), whereas only constipation (p = 0.045) and bloating (p = 0.001) were improved in the control group. PAI-1 levels tended to be decreased in the intervention group (p = 0.066), with a difference in the decrease between groups (p = 0.022). Visfatin levels were decreased in the intervention group (p = 0.007). There were few correlations between hormonal levels and symptoms. Thus, this diet not only improves IBS symptoms but also seems to have a general health-promoting effect.

Evening chronotype is associated with elevated biomarkers of cardiometabolic risk in the EpiHealth cohort: a cross-sectional study

STUDY OBJECTIVES

Individuals with evening chronotype have a higher risk of cardiovascular and metabolic disorders, although the underlying mechanisms are not well understood. In a population-based cohort, we aimed to investigate the association between chronotype and 242 circulating proteins from three panels of established or candidate biomarkers of cardiometabolic processes.

METHODS

In 2,471 participants (49.7% men, mean age 61.2±8.4 SD years) from the EpiHealth cohort, circulating proteins were analyzed with a multiplex proximity extension technique. Participants self-reported their chronotype on a five-level scale from extreme morning to extreme evening chronotype. With the intermediate chronotype set as the reference, each protein was added as the dependent variable in a series of linear regression models adjusted for confounders. Next, the chronotype coefficients were jointly tested and the resulting p-values adjusted for multiple testing using false discovery rate (5%). For the associations identified, we then analyzed the marginal effect of each chronotype category.

RESULTS

We identified 17 proteins associated with chronotype. Evening chronotype was positively associated with proteins previously linked to insulin resistance and cardiovascular risk, namely retinoic acid receptor protein 2, fatty acid-binding protein adipocyte, tissue-type plasminogen activator, and plasminogen activator inhibitor 1 (PAI-1). Additionally, PAI-1 was inversely associated with the extreme morning chronotype.

CONCLUSIONS

In this population-based study, proteins previously related with cardiometabolic risk were elevated in the evening chronotypes. These results may guide future research in the relation between chronotype and cardiometabolic disorders.

Insulin resistance is linked to a specific profile of immune activation in human subjects

We tested the hypothesis that a particular immune activation profile might be correlated with insulin resistance in a general population. By measuring 43 markers of immune, endothelial, and coagulation activation, we have previously shown that five different immune activation profiles may be distinguished in 150 volunteers. One of these profiles, Profile 2, characterized by CD4+ T cell senescence, inflammation, monocyte, B cell, and endothelial activation, presented elevated insulinemia, glycemia, triglyceridemia, and γ-glutamyl transferase, a marker of liver injury, in comparison with other profiles. Our data are compatible with a model in which a particular immune activation profile might favor the development of insulin resistance and metabolic syndrome. In this hypothesis, identification of this profile, that is feasible with only 3 markers with an error rate of 5%, might allow to personalize the screening and prevention of metabolic syndrome-driven morbidities as liver steatosis.

A Serpin With a Finger in Many PAIs: PAI-1's Central Function in Thromboinflammation and Cardiovascular Disease

Plasminogen activator inhibitor 1 (PAI-1) is a member of the serine protease inhibitor (serpin) superfamily. PAI-1 is the principal inhibitor of the plasminogen activators, tissue plasminogen activator (tPA), and urokinase-type plasminogen activator (uPA). Turbulence in the levels of PAI-1 tilts the balance of the hemostatic system resulting in bleeding or thrombotic complications. Not surprisingly, there is strong evidence that documents the role of PAI-1 in cardiovascular disease. The more recent uncovering of the coalition between the hemostatic and inflammatory pathways has exposed a distinct role for PAI-1. The storm of proinflammatory cytokines liberated during inflammation, including IL-6 and TNF-α, directly influence PAI-1 synthesis and increase circulating levels of this serpin. Consequently, elevated levels of PAI-1 are commonplace during infection and are frequently associated with a hypofibrinolytic state and thrombotic complications. Elevated PAI-1 levels are also a feature of metabolic syndrome, which is defined by a cluster of abnormalities including obesity, type 2 diabetes, hypertension, and elevated triglyceride. Metabolic syndrome is in itself defined as a proinflammatory state associated with elevated levels of cytokines. In addition, insulin has a direct impact on PAI-1 synthesis bridging these pathways. This review describes the key physiological functions of PAI-1 and how these become perturbed during disease processes. We focus on the direct relationship between PAI-1 and inflammation and the repercussion in terms of an ensuing hypofibrinolytic state and thromboembolic complications. Collectively, these observations strengthen the utility of PAI-1 as a viable drug target for the treatment of various diseases.

Interacting hepatic PAI-1/tPA gene regulatory pathways influence impaired fibrinolysis severity in obesity

Fibrinolysis is initiated by tissue-type plasminogen activator (tPA) and inhibited by plasminogen activator inhibitor 1 (PAI-1). In obese humans, plasma PAI-1 and tPA proteins are increased, but PAI-1 dominates, leading to reduced fibrinolysis and thrombosis. To understand tPA–PAI-1 regulation in obesity, we focused on hepatocytes, a functionally important source of tPA and PAI-1 that sense obesity-induced metabolic stress. We showed that obese mice, like humans, had reduced fibrinolysis and increased plasma PAI-1 and tPA, due largely to their increased hepatocyte expression. A decrease in the PAI-1 (SERPINE1) gene corepressor Rev-Erbα increased PAI-1, which then increased the tPA gene PLAT via a PAI-1/LRP1/PKA/p-CREB1 pathway. This pathway was partially counterbalanced by increased DACH1, a PLAT-negative regulator. We focused on the PAI-1/PLAT pathway, which mitigates the reduction in fibrinolysis in obesity. Thus, silencing hepatocyte PAI-1, CREB1, or tPA in obese mice lowered plasma tPA and further impaired fibrinolysis. The PAI-1/PLAT pathway was present in primary human hepatocytes, and associations among PAI-1, tPA, and PLAT in livers from obese and lean humans were consistent with these findings. Knowledge of PAI-1 and tPA regulation in hepatocytes in obesity may suggest therapeutic strategies for improving fibrinolysis and lowering the risk of thrombosis in this setting.

Impact of Polytrauma and Acute Respiratory Distress Syndrome on Markers of Fibrinolysis: A Prospective Pilot Study

Acute respiratory distress syndrome (ARDS), which is associated with major morbidity and high mortality, is commonly developed by polytraumatized patients. Its pathogenesis is complex, and its development is difficult to anticipate, as candidate biomarkers for the prediction of ARDS were found not to be reliable for clinical use. In this prospective study, we assessed the serum antigen levels of tissue plasminogen activator (tPA) and plasminogen activator inhibitor type-1 (PAI-1) of 28 survivors of blunt polytrauma (age ≥18 years; injury severity score ≥16) at admission and on days 1, 3, 5, 7, 10, 14, and 21 of hospitalization. Our results show that these patients presented high mean tPA and PAI-1 antigen levels at admission; despite their decline, these parameters remained elevated for 3 weeks. Over this period, the mean tPA antigen level was higher in polytrauma victims suffering from ARDS than in those without ARDS, whereas the mean PAI-1 level was higher in polytrauma victims sustaining pneumonia than in those without pneumonia. Moreover, in each individual developing ARDS, the polytrauma-related elevated tPA antigen level either continued to rise after admission or suffered a second increase up to the onset of ARDS, declining immediately thereafter. Therefore, our findings support the assessment of serum tPA antigen levels after the initial treatment of polytraumatized patients, as this parameter shows potential as a biomarker for the development of ARDS and for the consequent identification of high-risk individuals.

First trimester prediction of gestational diabetes mellitus using plasma biomarkers: a case-control study

Objectives To evaluate the first trimester maternal biomarkers for early pregnancy prediction of gestational diabetes mellitus (GDM). Methods The study was a case-control study of healthy women with singleton pregnancies at the first trimester carried out at the Obstetrics and Gynecology Unit, Clinica Davila, Santiago, Chile. After obtaining informed consent, peripheral blood samples of pregnant women under 14 weeks of gestation were collected. At 24-28 weeks of pregnancy, women were classified as GDM (n=16) or controls (n=80) based on the results of a 75-g oral glucose tolerance test (OGTT). In all women, we measured concentrations of fasting blood glucose, insulin, glycated hemoglobin, uric acid, cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), triglycerides, aspartate aminotransferase (AST), alanine aminotransferase (ALT), γ-glutamyl transpeptidase (GGT), alkaline phosphatase (AP), sex hormone-binding globulin (SHBG), adiponectin, tissue plasminogen activator (t-PA), leptin and placental growth factor (PGF). Results The GDM group displayed an increased median concentration of cholesterol (P=0.04), triglycerides (P=0.003), insulin (P=0.003), t-PA (P=0.0088) and homeostatic model assessment (HOMA) (P=0.003) and an increased mean concentration of LDL (P=0.009) when compared to the control group. The receiver operating characteristic (ROC) curve for significant variables achieved an area under the curve (AUC) of 0.870, a sensitivity of 81.4% and a specificity of 80.0%. The OGTT was positive for GDM according to the IADPSG (International Diabetes in Pregnancy Study Group) criteria. Conclusion Women who subsequently developed GDM showed higher levels of blood-borne biomarkers during the first trimester, compared to women who did not develop GDM. These data warrant validation in a larger cohort.

Treadmill exercise alleviates diabetic cardiomyopathy by suppressing plasminogen activator inhibitor expression and enhancing eNOS in streptozotocin-induced male diabetic rats

OBJECTIVE

To investigate the biological mechanism of the effect of different intensity exercises on diabetic cardiomyopathy.

METHODS

87 raise specific pathogen SPF healthy 6-week-old male Sprague-Dawley rats, fed 6 weeks with high-fat diet for rats were used, and a diabetic model was established by intraperitoneal injection of streptozotocin - randomly selected 43 rats were divided into Diabetic control group (DCG, n = 10), Diabetic exercise group 1 (DEG1, n = 11), Diabetic exercise group 2 (DEG2, n = 11) and Diabetic exercise group 3 (DEG3, n = 11). The rats in DEG1 were forced to run on a motorized treadmill, the exercise load consisted of running at a speed of 10 m/min, the exercise load of the rats in DEG2 were running at a speed of 15 m/min, the exercise load of the rats in DEG3 were running at a speed of 20 m/min, for one hour once a day for 6 weeks. After 6 weeks of exercise intervention, glucose metabolism-related indexes in rats such as blood glucose (FBG), glycosylated serum protein (GSP) and insulin (FINS); cardiac fibrinolytic system parameters such as PAI-1 (plasminogen activator inhibitor 1), Von Willebrand factor (vWF), protein kinase C (PKC) and diacylglycerol (DAG); and serum level of NO, eNOS and T-NOS were measured.

RESULT

Compared with DCG, fasting blood glucose and GSP were decreased, while insulin sensitivity index and insulin level were increased in all rats of the three exercise groups. FBG decrease was statistically significant (P < 0.01), only GSP decrease was statistically significant (P < 0.05) in DEG1 and DEG2, PAI-1 in three exercise groups were significantly reduced (P < 0.05), plasma vWF levels in the three exercise groups were significantly lower than those in the DCG group (P < 0.01); PKC levels decreased dramatically in the three exercise groups and DAG levels decrease slightly (P < 0.05), but with no significant difference. Compared with DCG, the serum level of NO was significantly higher (P < 0.05), and eNOS level was significantly elevated (P < 0.05). T-NOS elevation was statistically significant in DEG1 (P < 0.05).

CONCLUSIONS

Low- and moderate-intensity exercise can better control blood glucose level in diabetic rats; myocardial PAI-1 in DEG1, DEG2 and DEG3 rats decreased significantly (P < 0.05), serum NO increased (P < 0.05) and eNOS increased (P < 0.05) significantly. Therefore, it is inferred that exercise improves the biological mechanism of diabetic cardiomyopathy by affecting the levels of PAI-1 and eNOS, and there is a dependence on intensity.

The effect of basal insulin glargine on the fibrinolytic system and von Willebrand factor in people with dysglycaemia and high risk for cardiovascular events: Swedish substudy of the Outcome Reduction with an Initial Glargine Intervention trial

INTRODUCTION

Fibrinolytic factors, plasminogen activator inhibitor-1, tissue plasminogen activator, tissue plasminogen activator/plasminogen activator-complex and the haemostatic factor von Willebrand factor are known markers of cardiovascular disease. Their plasma levels are adversely affected in patients with dysglycaemia, and glucose normalization with insulin glargine might improve the levels of these factors.

METHODS

Prespecified Swedish substudy of the Outcome Reduction with an Initial Glargine Intervention trial (ClinicalTrials.gov number, NCT00069784). Tissue plasminogen activator activity, tissue plasminogen activator antigen, plasminogen activator inhibitor-1 antigen, tissue plasminogen activator/plasminogen activator inhibitor-1 complex and von Willebrand factor were analysed at study start, after 2 years and at the end of the study (median follow-up of 6.2 years).

RESULTS

Of 129 patients (mean age of 64 ± 7 years, females: 19%), 68 (53%) and 61 (47%) were randomized to the insulin glargine and standard care group, respectively. Allocation to insulin glargine did not significantly affect the studied fibrinolytic markers or von Willebrand factor compared to standard care. Likewise, there were no significant differences in plasminogen activator inhibitor-1, tissue plasminogen activator antigen and von Willebrand factor. During the whole study period, the within-group analysis revealed a curvilinear pattern and significant changes for tissue plasminogen activator/plasminogen activator inhibitor-1 complex, tissue plasminogen activator antigen and von Willebrand factor in the insulin glargine but not in the standard care group.

CONCLUSION

In people with dysglycaemia and other cardiovascular risk factors, basal insulin does not improve the levels of markers of fibrinolysis or von Willebrand factor compared to standard glucose-lowering treatments.

Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) in diabetic foot syndrome

PURPOSE

The aim was to evaluate tissue plasminogen activator (tPA) and plasminogen activator inhibitor type 1 (PAI-1) concentration using enzyme linked immunosorbent assay method (ELISA) in diabetic foot syndrome (DFS) as compared to a group of healthy people and patients with diabetes mellitus without symptomatic vascular complications (DM2T).

MATERIAL/METHODS

Venous blood samples were collected from 90 patients with type 2 diabetes mellitus (30 - DM2T; 60 - DFS). Age-matched controls were also included (n=30). tPA and PAI-1 plasma levels were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We found a significantly lower concentration of tPA:Ag in patients with DFS in comparison to the DM2T group; tPA concentrations were significantly higher in DM2T as compared to the control group. We observed significantly lower concentration of PAI-1:Ag in DF patients treated for hypertension as compared to patients without hypertension. The tPA:Ag and PAI-1:Ag concentration analysis in DFS depending on age, gender and BMI did not show any significant differences.

CONCLUSIONS

A lower concentration of tPA in patients with DFS may be associated with damage to the endothelial cells, especially in the microvasculature, and the sympathetic nervous system.

Association of smoking and concomitant metformin use with cardiovascular events and mortality in people newly diagnosed with type 2 diabetes

BACKGROUND

The cardiovascular and mortality risk in patients with incident type 2 diabetes (T2D) in relation to smoking status and concurrent use of metformin is not well known.

METHODS

A cohort study was performed in 82,205 incident T2D patients from the U.K. Clinical Practice Research Datalink. In the present study, the risks of myocardial infarction (MI), stroke, and mortality in incident T2D patients were evaluated in relation to their smoking status with and without concurrent use of metformin.

RESULTS

Over a median 5.4 years of follow-up, of patients without a history of cardiovascular disease (CVD) before a diagnosis of diabetes (n = 63,166), current smokers with and without metformin had an 8% (hazard ratio [HR] 1.08; 95% confidence interval [CI] 0.81, 1.45) and 32% (HR 1.32; 95% CI 1.07, 1.65) increased risk of MI or stroke, respectively, compared with non-smokers without metformin treatment. The respective HRs (95% CI) for mortality in these patients were 0.96 (0.83, 1.11) and 1.86 (1.68, 2.07). The HR for mortality among ex-smokers with and without concurrent metformin treatment was 0.92 (95% CI 0.83, 1.11) and 1.19 (95% CI 1.10, 1.30), respectively. Similar beneficial modifiable effects of metformin among ex- and current smokers were observed in patients with CVD before diagnosis of diabetes (n = 19,039).

CONCLUSIONS

In T2D patients, concurrent treatment with metformin attenuates the observed higher cardiovascular and mortality risk in ex- and current smokers. In addition to smoking cessation support, treatment with metformin, particularly in ex- and current smokers, should be encouraged.

Markers of fibrinolysis may predict development of lower extremity arterial disease in patients with diabetes: A longitudinal prospective cohort study with 10 years of follow-up

BACKGROUND

A previous cross-sectional study suggested that tissue plasminogen activator-activity might be an early marker of asymptomatic lower extremity arterial disease, but the long-term relationship is unknown.

SUBJECTS AND METHODS

This study included 96 diabetic (48 type 1/48 type 2) and 62 non-diabetic subjects aged 30-70 years without previously known lower extremity arterial disease (age: 50.3 ± 9.3 years, gender: M/W 47.5/52.5% and body mass index: 26.6 ± 4.5 kg/m(2)). The relationships between asymptomatic lower extremity arterial disease and fibrinolytic markers (tissue plasminogen activator-activity, tissue plasminogen activator-mass, plasminogen activator inhibitor-1 activity) at baseline and after 10 years were assessed by logistic regression analysis adjusting for age, hypertension, statin treatment, HbA1c, triglycerides and low-density lipoprotein cholesterol as fixed covariates.

RESULTS

The tissue plasminogen activator-activity at baseline and at the 10-year follow-up significantly predicted the presence of sign(s) of lower extremity arterial disease (odds ratio = 1.78, 95% confidence interval: 1.02-3.10, p = 0.043 and odds ratio = 1.78, 95% confidence interval: 1.12-2.23, p = 0.014, respectively). In addition, tissue plasminogen activator-mass at the 10-year follow-up was associated with signs of lower extremity arterial disease (odds ratio = 1.07, 95% confidence interval: 1.00-1.15, p = 0.046). Baseline age, hypertension and HbA1c were independently associated with sign(s) of lower extremity arterial disease at 10 years (odds ratio = 1.09, 95% confidence interval: 1.04-1.14, p = < 0.001; odds ratio = 3.68, 95% confidence interval: 1.67-8.12, p = 0.001 and odds ratio = 1.54, 95% confidence interval: 1.21-1.95, p = < 0.001, respectively).

CONCLUSION

This long-term study supports previous findings of a significant association between asymptomatic lower extremity arterial disease and tissue plasminogen activator-activity. Thus, tissue plasminogen activator-activity may be an early marker of lower extremity arterial disease although the mechanism of this relationship remains unclear.

Plasminogen activator inhibitor-1 and type 2 diabetes: a systematic review and meta-analysis of observational studies

An emerging body of evidence has implicated plasminogen activator inhibitor-1 (PAI-1) in the development of type 2 diabetes (T2D), though findings have not always been consistent. We systematically reviewed epidemiological studies examining the association of PAI-1 with T2D. EMBASE, PubMed, Web of Science, and the Cochrane Library were searched to identify studies for inclusion. Fifty-two studies (44 cross-sectional with 47 unique analytical comparisons and 8 prospective) were included. In pooled random-effects analyses of prospective studies, a comparison of the top third vs. bottom third of baseline PAI-1 values generated a RR of T2D of 1.67 (95% CI 1.28–2.18) with moderate heterogeneity (I² = 38%). Additionally, of 47 cross-sectional comparisons, 34(72%) reported significantly elevated PAI-1 among diabetes cases versus controls, 2(4%) reported significantly elevated PAI-1 among controls, and 11(24%) reported null effects. Results from pooled analyses of prospective studies did not differ substantially by study design, length of follow-up, adjustment for various putative confounding factors, or study quality, and were robust to sensitivity analyses. Findings from this systematic review of the available epidemiological literature support a link between PAI-1 and T2D, independent of established diabetes risk factors. Given the moderate size of the association and heterogeneity across studies, future prospective studies are warranted.

Protein Biomarkers for Insulin Resistance and Type 2 Diabetes Risk in Two Large Community Cohorts

Insulin resistance (IR) is a precursor of type 2 diabetes (T2D), and improved risk prediction and understanding of the pathogenesis are needed. We used a novel high-throughput 92-protein assay to identify circulating biomarkers for HOMA of IR in two cohorts of community residents without diabetes (n = 1,367) (mean age 73 ± 3.6 years). Adjusted linear regression identified cathepsin D and confirmed six proteins (leptin, renin, interleukin-1 receptor antagonist [IL-1ra], hepatocyte growth factor, fatty acid-binding protein 4, and tissue plasminogen activator [t-PA]) as IR biomarkers. Mendelian randomization analysis indicated a positive causal effect of IR on t-PA concentrations. Two biomarkers, IL-1ra (hazard ratio [HR] 1.28, 95% CI 1.03-1.59) and t-PA (HR 1.30, 1.02-1.65) were associated with incident T2D, and t-PA predicted 5-year transition to hyperglycemia (odds ratio 1.30, 95% CI 1.02-1.65). Additional adjustment for fasting glucose rendered both coefficients insignificant and revealed an association between renin and T2D (HR 0.79, 0.62-0.99). LASSO regression suggested a risk model including IL-1ra, t-PA, and the Framingham Offspring Study T2D score, but prediction improvement was nonsignificant (difference in C-index 0.02, 95% CI -0.08 to 0.12) over the T2D score only. In conclusion, proteomic blood profiling indicated cathepsin D as a new IR biomarker and suggested a causal effect of IR on t-PA.

The role of dietary coconut for the prevention and treatment of Alzheimer's disease: potential mechanisms of action

Coconut, Cocos nucifera L., is a tree that is cultivated to provide a large number of products, although it is mainly grown for its nutritional and medicinal values. Coconut oil, derived from the coconut fruit, has been recognised historically as containing high levels of saturated fat; however, closer scrutiny suggests that coconut should be regarded more favourably. Unlike most other dietary fats that are high in long-chain fatty acids, coconut oil comprises medium-chain fatty acids (MCFA). MCFA are unique in that they are easily absorbed and metabolised by the liver, and can be converted to ketones. Ketone bodies are an important alternative energy source in the brain, and may be beneficial to people developing or already with memory impairment, as in Alzheimer's disease (AD). Coconut is classified as a highly nutritious 'functional food'. It is rich in dietary fibre, vitamins and minerals; however, notably, evidence is mounting to support the concept that coconut may be beneficial in the treatment of obesity, dyslipidaemia, elevated LDL, insulin resistance and hypertension - these are the risk factors for CVD and type 2 diabetes, and also for AD. In addition, phenolic compounds and hormones (cytokinins) found in coconut may assist in preventing the aggregation of amyloid-β peptide, potentially inhibiting a key step in the pathogenesis of AD. The purpose of the present review was to explore the literature related to coconut, outlining the known mechanistic physiology, and to discuss the potential role of coconut supplementation as a therapeutic option in the prevention and management of AD.

Effects of a lifestyle program on vascular reactivity in macro- and microcirculation in severely obese adolescents

CONTEXT AND OBJECTIVE

This study aimed to comprehensively assess the macro- and microcirculation of severely obese adolescents (SOA) and normal-weight counterparts and to determine the longitudinal effects of weight loss on vascular function in SOA. DESIGN, SETTING, PARTICIPANTS, AND OUTCOME MEASURES: Seventeen SOA (body mass index z-score = 4.22 ± 0.73) and 19 puberty-matched normal-weight counterparts (body mass index z-score = -0.02 ± 1.04) were included. The SOA participated in a 4 month weight loss program. Brachial artery flow-mediated dilation and response to sublingual nitrate (nitrate-mediated dilation [NMD]) were assessed by high-resolution ultrasound. Microvascular reactivity was evaluated by laser Doppler flowmetry in response to NMD, iontophoresis of acetylcholine and sodium nitroprusside, and local hyperthermia. Plasma insulin, leptin, resistin, C-reactive protein, myeloperoxidase, and tissue plasminogen activator were measured.

RESULTS

At baseline, SOA had similar flow-mediated dilation and impaired NMD in the brachial artery compared to normal-weight adolescents. Similarly, peak responses to acetylcholine and sodium nitroprusside iontophoresis and to local hyperthermia were unaltered, whereas cutaneous blood flow after NMD was lower in the forearm microcirculation of SOA. All plasma measurements were significantly higher in SOA. After the 4-month program, SOA presented a weight reduction of 7.4 ± 3.1%, but neither brachial artery nor microvascular reactivity variables were improved. Significant decreases were detected in plasma leptin, myeloperoxidase, and tissue plasminogen activator.

CONCLUSIONS

Macro- and microvascular endothelial function are preserved in adolescents with severe obesity. Conversely, weight loss does not improve their impaired smooth muscle response to exogenous organic nitrate in both vascular beds, despite reducing plasma markers adversely related to vascular homeostasis.

The association of inflammatory and fibrinolytic proteins with 5 year change in insulin clearance: the Insulin Resistance Atherosclerosis Study (IRAS)

AIMS/HYPOTHESIS

Insulin clearance may decline as an early mechanism compensating for deteriorating insulin sensitivity. However, no previous studies have investigated the association between subclinical inflammation or impaired fibrinolysis and insulin clearance. We examined the association between plasminogen activator inhibitor (PAI)-1, C-reactive protein (CRP), TNF-α, leptin and fibrinogen and the progression of metabolic clearance rate of insulin (MCRI) over time.

METHODS

We studied 784 non-diabetic white, Hispanic and African-American individuals in the Insulin Resistance Atherosclerosis Study (IRAS). Insulin sensitivity, acute insulin response and MCRI were determined from frequently sampled intravenous glucose tolerance tests at baseline and at 5-year follow-up. Inflammatory and fibrinolytic proteins were measured in fasting plasma at baseline.

RESULTS

MCRI had declined significantly by 29% at the 5-year follow-up. We observed a significant association between higher plasma PAI-1 levels and the decline in MCRI in multivariable-adjusted regression models (β = -0.045 [95% CI -0.081, -0.0091]). Higher plasma CRP and leptin levels were associated with a decline in MCRI in unadjusted models, but these associations were non-significant after adjusting for BMI and waist circumference (β = -0.016 [95% CI -0.041, 0.0083] for CRP; β = -0.044 [95% CI -0.10, 0.011] for leptin). A higher plasma TNF-α concentration was associated with a decline in MCRI in unadjusted (β = -0.071 [95% CI -0.14, -0.00087]) but not in multivariable-adjusted (β = -0.056 [95% CI -0.13, 0.017]) models. Plasma fibrinogen level was not associated with the change in MCRI.

CONCLUSIONS/INTERPRETATION

We identified that higher plasma PAI-1 (but not CRP, TNF-α, leptin or fibrinogen) levels independently predicted the progressive decline of insulin clearance in the multiethnic cohort of the IRAS.

Signs of dysregulated fibrinolysis precede the development of type 2 diabetes mellitus in a population-based study

Background

Diabetic patients experience stimulated coagulation and dysfibrinolysis, which is associated with an increased risk of cardiovascular events. This imbalance may precede the manifest diagnosis. We investigated whether elevated antigen levels of tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), the tPA/PAI-1 complex, or von Willebrand Factor (VWF) precede type 2 diabetes mellitus (T2DM) diagnosis, and whether this elevation occurs before increased fasting plasma glucose (FPG) or 2-hour plasma glucose (2hPG) in individuals who later develop T2DM.

Methods

We conducted a prospective incident case-referent study within the Västerbotten Intervention Programme. Cardiovascular risk factor data as well as FPG and 2hPG and blood samples for future research were collected at a baseline health examination between 1989 and 2000, (n= 28 736). During follow-up in January 2001, 157 cases had developed T2DM. Referents without T2DM were matched for sex, age, and year of participation (n=277). Subgroup analysis was performed for cases with normal baseline glucose levels (FPG <6.1 mmol/L and 2hPG < 8.9 mmol/L) and cases with elevated levels (FPG 6.1-6.9 mmol/L and/or 2hPG 8.9-12.1 mmol/L).

Results

After adjusting for BMI, family history of diabetes, physical activity, smoking, systolic blood pressure and levels of C-reactive protein and triglycerides, independent associations were found between incident T2DM and elevated levels of tPA (OR=1.54, 95% CI 1.06-2.23), PAI-1 (OR=1.61, 95% CI 1.14-2.28), and tPA/PAI-1 complex (OR=2.45, 95% CI 1.56-3.84). In participants with normal glucose levels, PAI-1 (OR=2.06, 95% CI 1.10 - 3.86) exhibited an independent relationship with incident T2DM after the adjustments.

Conclusions

Elevated levels of fibrinolytic variables precede the manifestation of T2DM after adjusting for metabolic and cardiovascular risk factors and can be detected several years before changes in glucose tolerance.

Elevation of sE-Selectin Levels 2-24 Months following Gestational Diabetes Is Associated with Early Cardiometabolic Risk in Nondiabetic Women

Objective. We hypothesised that the endothelial dysfunction is associated with early glucose dysregulation and/or atherosclerosis risk factors in nondiabetic women with a previous history of gestational diabetes (pGDM). Material/Methods. Anthropometric parameters, glucose regulation (OGTT), insulin resistance (HOMA), lipids, biomarkers of endothelial dysfunction, and inflammation were evaluated in 85 women with pGDM and in 40 controls 2-24 months postpartum. Results. The pGDM group consisted of 67% normoglycemic women (pGDM-N) and 33% with prediabetic state (pGDM-P). The BMI, waist circumference, fasting and 2 h glucose (OGTT), soluble adhesion molecules, tissue plasminogen activator antigen, high sensitivity C-reactive protein, total-, LDL-cholesterol, and triglycerides/HDL-cholesterol ratio were higher in the pGDM women compared with the controls. After adjustment for BMI and fasting glucose, only higher triglycerides, higher TG/HDL and lower HDL-cholesterol were associated with pGDM. The pGDM-P differed from pGDM-N for only higher triglycerides and TG/HDL. The plasma level of sE-selectin was not independently associated with glucose concentration in pGDM group. sE-selectin level correlated with triglycerides, TG/HDL, plasminogen activator inhibitor-1 antigen, and sICAM-1. Conclusions. sE-selectin level correlated with components of metabolic syndrome, but only the atherogenic lipid profile was independently associated with a previous history of GDM in nondiabetic women 2-24 months postpartum.

The relationship among TAFI, t-PA, PAI-1 and F1 + 2 in type 2 diabetic patients with normoalbuminuria and microalbuminuria

Disturbances of coagulation and fibrinolysis in type 2 diabetes mellitus (DM2) contribute to increased rates of macrovascular complications such as myocardial infarction and ischemic stroke. The aim of the study was to investigate the relationship among plasminogen activator inhibitor 1 (PAI-1), thrombin-activable fibrinolysis inhibitor (TAFI), tissue plasminogen activator (t-PA), prothrombin fragments 1+2 (F1+2), glycemic control, hypertension, sex and body mass index (BMI) in DM2 patients with normoalbuminuria and microalbuminuria. Forty-two normoalbuminuric (NAU), 42 microalbuminuric (MAU) patients with DM2 and 42 blood donors as control group were enrolled. TAFI, PAI-1, t-PA and F1+2 were assessed by enzyme-linked immunosorbent assay (ELISA) in all patients. TAFI was significantly increased in the MAU group, PAI-1 and F1+2 were increased in both groups and t-PA was not elevated in either group compared to controls. We found positive correlations in the NAU: TAFI and fibrinogen (r=0.65, P=0.02), PAI-1 and triglycerides (r=0.67, P=0.01), in the MAU: TAFI and F1+2 (r=0.48, P=0.02), TAFI and systolic blood pressure (r=0.53, P=0.01), PAI-1 and BMI (r=0.43, P<0.05). We found decreased fibrinolysis in DM2 patients presented with increased PAI-1 in both NAU and MAU. Hypofibrinolysis in MAU is further accented by the elevation of TAFI. TAFI-mediated inhibition of fibrinolysis in DM2 is regulated independently from PAI-1. Patient[Combining Acute Accent]s sex does not affect diabetes-related changes in hemostasis and fibrinolysis.

Inflammation and thrombosis in diabetes

Patients with diabetes mellitus are at increased risk of cardiovascular morbidity and mortality. Atherothrombosis, defined as atherosclerotic lesion disruption with superimposed thrombus formation, is the most common cause of death among these patients. Following plaque rupture, adherence of platelets is followed by local activation of coagulation, the formation of a cross-linked fibrin clot and the development of an occlusive platelet rich fibrin mesh. Patients with diabetes exhibit a thrombotic risk clustering which is composed of hyper-reactive platelets, up regulation of pro-thrombotic markers and suppression of fibrinolysis. These changes are mainly mediated by the presence of insulin resistance and dysglycaemia and an increased inflammatory state which directly affects platelet function, coagulation factors and clot structure. This prothrombotic state is related to increased cardiovascular risk and may account for the reduced response to antithrombotic therapeutic approaches, underpinning the need for adequate antithrombotic therapy in patients with diabetes to reduce their cardiovascular mortality.

Plasminogen activator inhibitor-1 and HbA1c defined prediabetes: the Guangzhou Biobank Cohort Study-CVD

OBJECTIVE

To examine the association between plasminogen activator inhibitor-1 (PAI-1) and diabetes status.

RESEARCH DESIGN AND METHODS

One thousand three hundred and ninety-three older Chinese were randomly selected from the Guangzhou Biobank Cohort Study. Diabetes status was classified as impaired HbA1c (IA1c) level of 5·7-6·4%, impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or diabetes using the American Diabetes Association diagnosis criteria in 2010.

RESULTS

Compared to the normoglycemic (NG) group, 421 subjects with IA1c, but without diabetes, IFG or IGT, had adverse levels of vascular risk factors, including PAI-1, lipid profile, blood pressure and anthropometry. After adjusting for multiple potential confounders, compared to the NG group, the level of plasma PAI-1 was independently and significantly increased in the IA1c and the IFG/IGT group (mean difference: 32·0 (95% confidence interval: 5·5-58·6) ng/ml and 33·3 (6·3-60·3) ng/ml, respectively; P<0·01).

CONCLUSIONS

Plasma PAI-1 level was increased in people with haemoglobin A1c (HbA1c) of 5·7-6·4% but without IFG or IGT, and in people with IFG/IGT, suggesting an increased risk for future diabetes and cardiovascular diseases in these groups.

Association of plasminogen activator inhibitor-1 and tissue plasminogen activator with type 2 diabetes and metabolic syndrome in Malaysian subjects

Background

Increased plasma plasminogen activator inhibitor-1 (PAI-1) activity and decreased tissue plasminogen activator (tPA) activity could be considered a true component of the metabolic syndrome (MetS) associated with an increased risk of developing cardiovascular diseases (CVD) and fibrinolytic abnormalities. The aim of this study was to investigate the association of tPA and its inhibitor PAI-1 with type 2 diabetes (T2D) and MetS and interrelationship between PAI-1and tPA activities and antigens in Malaysian T2D and normal subjects.

Methods

The plasma activities and antigens of PAI-1 and tPA and the levels of the tPA/PAI-1 complex as well as serum insulin, parameter of the coronary risk panel and plasma glucose at fasting state were studied in 303 T2D subjects (227 with MetS and 76 without MetS), 131 normal non-diabetic non-metabolic subjects and 101 non-diabetic MetS subjects.

Results

The PAI-1 activity was higher in subjects with T2D with MetS (P = 9.8 × 10^-19) and non-diabetic subjects with MetS (P = 3.0 × 10^-15), whereas the tPA activity was lower in T2D with MetS (P = 0.003) as compare to normal subjects. Plasma tPA antigen levels were higher in subjects with T2D with MetS (P = 8.9 × 10^-24), T2D without MetS (P = 1.3 × 10^-13) and non-diabetic MetS subjects (P = 0.002). The activity and antigen of PAI-1 in normal subjects were related to insulin resistance (P = 2.2 × 10^-4; 0.007). Additionally, the PAI-1 activity was associated with an increased waist circumference (P = 2.2 × 10^-4) and decreased HDL-c (P = 0.005), whereas the tPA activity was associated with decreased FBG (P = 0.028). The highest correlation was between PAI-1 activity and its antigen (R² = 0.695, P = 1.1 × 10^-36) in diabetic subjects. The tPA activity negatively correlated with its antigen (R² = -0.444, P = 7.7 × 10^-13) in normal subjects and with the PAI-1 activity and antigen (R² = -0.319, P = 9.9 × 10^-12; R2 = -0.228, P = 3.4 × 10^-6) in diabetic subjects.

Conclusions

PAI-1 and tPA activities and antigens were associated with diabetes and MetS parameters in Malaysian subjects.

Gingival crevicular fluid IL-6, tPA, PAI-2, albumin levels following initial periodontal treatment in chronic periodontitis patients with or without type 2 diabetes

OBJECTIVES

To evaluate initial periodontal treatment effects on gingival crevicular fluid (GCF) interleukin-6 (IL-6), tissue-type plasminogen activator (tPA), plasminogen activator inhibitor-2 (PAI-2), albumin levels in type 2 diabetic patients.

DESIGN AND METHODS

GCF samples were collected from 20 type 2 diabetic, 22 non-diabetic non-smokers all with chronic periodontitis at baseline, 1-, 3-months following initial periodontal treatment. Biochemical analysis was performed by ELISA. Data were tested by Mann-Whitney U, Wilcoxon tests.

RESULTS

The total amounts of albumin, IL-6, tPA, PAI-2 decreased significantly in diabetics after treatment (1- and 3-months) whereas, only PAI-2 decreased in non-diabetic group at 3-months (p < 0.05). There were statistically significant differences between the diabetics and non-diabetics at all time points for albumin, PAI-2 and at 1-, 3-months for GCF volume (p < 0.050) but only at baseline for IL-6 (p < 0.050).

CONCLUSION

Present data suggest clinical improvements are less apparent in diabetic chronic periodontitis patients as reflected by disease markers in GCF and by an increase in concentrations of inflammatory proteins IL-6, tPA, and PAI-2 in GCF of this patient group following initial periodontal treatment.

Advanced proteomics procedure as a detection tool for predictive screening in type 2 pre-Diabetes

It has been suggested that a more precise selection of predictive biomarkers may prove useful in the early diagnosis of type 2 diabetes (T2D), even when glucose tolerance is normal. This is vital since many T2D cases may be preventable by avoiding those factors that trigger the disease process (primary prevention) or by use of therapy that modulates the disease process before the onset of clinical symptoms (secondary prevention) occurs. The selection of predictive markers must be carefully assessed and depends mainly on three important parameters: sensitivity, specificity and positive predictive value. Unfortunately, biomarkers with ideal specificity and sensitivity are difficult to find. One potential solution is to use the combinatorial power of different biomarkers, each of which alone may not offer satisfactory specificity and sensitivity. Recent technological advances in proteomics and bioinformatics offer a great opportunity for the discovery of different potential predictive markers. In this review, we described a cellular T2D model as an example with the intent of providing specific enrichment and new identification strategies, which might have the potential to improve predictive biomarker identification and to bring accuracy in disease diagnosis and classification, as well as therapeutic monitoring in the early phase of T2D.

Cytokine and cytokine-like inflammation markers, endothelial dysfunction, and imbalanced coagulation in development of diabetes and its complications

CONTEXT

Recent developments indicate that pathophysiological mechanisms leading to beta-cell damage, insulin resistance, and the vascular complications of diabetes include an activation of the inflammation cascade, endothelial dysfunction, and procoagulant imbalance. Their circulating biomarkers may therefore provide opportunities for early diagnosis and targets for novel treatments.

EVIDENCE

Circulating biomarkers of these pathways such as TNFalpha, IL-6, C-reactive protein (CRP) (inflammation), vascular cellular adhesion molecule-1, interstitial cellular adhesion molecule-1, E-selectin, von Willebrand factor (endothelial dysfunction), plasminogen activator inhibitor-1, fibrinogen, P-selectin (procoagulant state), and adiponectin (antiinflammation) may be associated with development of both type 1 and type 2 diabetes and some studies, particularly in type 2 diabetes, have demonstrated that certain biomarkers may have independent predictive value. Similarly studies have shown that these biomarkers may be associated with development of diabetic nephropathy and retinopathy, and again, particularly in type 2 diabetes, with cardiovascular events as well. Finally, the comorbidities of diabetes, namely obesity, insulin resistance, hyperglycemia, hypertension and dyslipidemia collectively aggravate these processes while antihyperglycemic interventions tend to ameliorate them.

CONCLUSIONS

Increased CRP, IL-6, and TNFalpha, and especially interstitial cellular adhesion molecule-1, vascular cellular adhesion molecule-1, and E-selectin are associated with nephropathy, retinopathy, and cardiovascular disease in both type 1 and type 2 diabetes. Whereas further work is needed, it seems clear that these biomarkers are predictors of increasing morbidity in prediabetic and diabetic subjects and should be the focus of work testing their clinical utility to identify high-risk individuals as well as perhaps to target interventions.

Novel biochemical risk factors for type 2 diabetes: pathogenic insights or prediction possibilities?

This review critically appraises studies examining the association of novel factors with diabetes. We show that many of the most studied novel and apparently 'independent' risk factors are correlated with each other by virtue of their common origins or pathways, and that residual confounding is likely. Available studies also have other limitations, including differences in methodology or inadequate statistical analyses. Furthermore, although most relevant work in this area has focused on improving our understanding of the pathogenesis of diabetes, association studies in isolation cannot prove causality; intervention studies with specific agents (if available) are required, and genetic studies may help. With respect to the potential value of novel risk factors for diabetes risk prediction, we illustrate why this work is very much in its infancy and currently not guaranteed to reach clinical utility. Indeed, the existence of several more easily measured powerful predictors of diabetes, suggests that the additional value of novel markers may be limited. Nevertheless, several suggestions to improve relevant research are given. Finally, we show that several risk factors for diabetes are only weakly associated with the risk of incident vascular events, an observation that highlights the limitations of attempting to devise unified criteria (e.g. metabolic syndrome) to identify individuals at risk of both CHD and diabetes.

Tissue plasminogen activator, von Willebrand factor, and risk of type 2 diabetes in older men

OBJECTIVE

The objective of this study was to assess the relationship between putative markers of endothelial dysfunction (tissue plasminogen activator [t-PA] antigen and von Willebrand factor [vWF] antigen) and development of type 2 diabetes, as well as the role of inflammation, adipokines, hepatic function, and insulin resistance in modifying these relationships.

RESEARCH DESIGN AND METHODS

This was a prospective study of 3,562 nondiabetic men aged 60-79 years followed up for an average of 7 years during which there were 162 incident cases of type 2 diabetes.

RESULTS

Elevated t-PA (top third) was associated with a near threefold increase in risk of diabetes compared with the risk in those in the bottom third after adjustment for lifestyle factors and waist circumference (relative risk [RR] 2.98 [95%CI 1.79-5.00]; P(trend) < 0.0001); weaker but significant (marginal) associations were seen with vWF (1.24 [0.83-1.85]; P = 0.05 for trend). Both biomarkers of endothelial dysfunction correlated significantly with markers of inflammation (interleukin-6 [IL-6] and C-reactive protein [CRP]), hepatic function (gamma-glutamyl transferase [GGT]), and insulin resistance, with t-PA showing stronger associations with adiposity, hepatic function, and insulin resistance than vWF. t-PA was also significantly and inversely associated with adiponectin. Adjustment for IL-6, adiponectin, and GGT attenuated the association of incident diabetes with vWF (1.06 [0.71-1.60]), but the relationship seen with t-PA remained significant (adjusted RR 2.19 [1.29-3.70]). Subsequent adjustment for insulin attenuated the association further, but t-PA was still associated with a significant increase in risk (1.66 [0.96-2.85]; P(trend) = 0.02).

CONCLUSION

t-PA antigen, but not vWF antigen, is independently associated with risk of type 2 diabetes.

A PAI-1 mutant, PAI-1R, slows progression of diabetic nephropathy

Plasminogen activator inhibitor-1 (PAI-1) has been implicated in renal fibrosis. In vitro, PAI-1 inhibits plasmin generation, and this decreases mesangial extracellular matrix turnover. PAI-1R, a mutant PAI-1, increases glomerular plasmin generation, reverses PAI-1 inhibition of matrix degradation, and reduces disease in experimental glomerulonephritis. This study sought to determine whether short-term administration of PAI-1R could slow the progression of glomerulosclerosis in the db/db mouse, a model of type 2 diabetes in which mesangial matrix accumulation is evident by 20 wk of age. Untreated uninephrectomized db/db mice developed progressive albuminuria and mesangial matrix expansion between weeks 20 and 22, associated with increased renal mRNA encoding alpha1(I) and (IV) collagens and fibronectin. Treatment with PAI-1R prevented these changes without affecting body weight, blood glucose, glycosylated hemoglobin, creatinine, or creatinine clearance; therefore, PAI-1R may prevent progression of glomerulosclerosis in type 2 diabetes.

Glucagon as a determinant of fibrinolytic activity in men with different stages of glucose tolerance: impact of glucagon on fibrinolysis

Glucagon plays an important role in postprandial hyperglycemia in type 2 diabetes (T2DM), and coexists with insulin resistance and impaired fibrinolysis. We analyzed the response of plasminogen activator inhibitor-1 (PAI-1) to a lipid-glucose-protein test and the relationship between glucagon and PAI-1, tissue plasminogen activator (t-PA) and PAI-1/t-PA in 26 men with normal glucose tolerance (NGT), nine with impaired glucose tolerance (IGT) and 12 with T2DM. Fasting and postprandial PAI-1 were higher in T2DM versus NGT (P < 0.05). In univariate analysis in NGT, fasting and area under the curve (AUC) PAI-1 showed a strong relationship with fasting (P = 0.003, P = 0.006) and postprandial (P = 0.041, P = 0.045) glucagon, t-PA with fasting glucagon (P = 0.014), and PAI-1/t-PA with fasting (P = 0.047) and AUC glucagon (P = 0.017). In IGT fasting, AUC PAI-1 and PAI-1/t-PA were associated with AUC glucagon (P = 0.035, P = 0.032, P = 0.023). In NGT with the fasting metabolic parameters and insulin resistance as independent variables, fasting glucagon remained an independent covariate for PAI-1 and PAI-1/t-PA. In another model, postprandial glucagon was independently associated with PAI-1/t-PA in NGT (P < 0.05). Besides the already established determinants, we found an independent association between glucagon and fibrinolysis in NGT. Further studies are needed to identify the link between glucagon, insulin resistance and hemostasis.

A randomized trial of lifestyle intervention in primary healthcare for the modification of cardiovascular risk factors

AIMS

To evaluate the effects of a lifestyle intervention programme in primary healthcare, targeted to patients with moderate to high risk of cardiovascular disease in terms of cardiovascular risk factors, physical activity, and quality of life.

METHOD

Randomized controlled trial with one-year follow-up, carried out in a primary healthcare centre in Northern Sweden. A total of 151 middle-aged men and women, with hypertension, dyslipidemia, type 2 diabetes, or obesity were enrolled. The subjects were randomized to either the intervention (n = 75) or the control group (n = 76). A total of 123 subjects completed the one-year follow-up.

INTERVENTIONS

Exercise: supervised endurance and circuit training in groups three times a week for three months. Diet: five group sessions of diet counselling with a dietitian. Follow- up meetings with a physiotherapist were conducted monthly thereafter. Primary outcomes were changes in anthropometry, maximal oxygen uptake, health-related quality of life, and self-reported physical activity. The secondary outcomes were changes in blood pressure and metabolic variables.

RESULTS

After one year the intervention group significantly increased maximal oxygen uptake, physical activity, and quality of life and significantly decreased body weight, waist and hip circumference, body mass index, waist-hip ratio, systolic and diastolic blood pressure, triglycerides, and glycosylated haemoglobin. There were significant differences between groups, mean changes (and their 95% confidence intervals, CI) in waist circumference -1.9 cm (-2.80 to -0.90; p<0.001), in waist-hip ratio -0.01 (-.02 to -0.004; p<0.01) and in diastolic blood pressure -2.3 mmHg (-4.04 to -0.51; p<0.05).

CONCLUSION

A prevention programme in primary healthcare with a focus on physical activity and diet counselling followed by structured follow-up meetings can favourably influence several risk factors for cardiovascular diseases and quality of life in high-risk subjects for at least one year.

Effects of Metformin on Microvascular Function and Exercise Tolerance in Women With Angina and Normal Coronary Arteries

OBJECTIVES

This study sought to determine whether metformin improves vascular function or myocardial ischemia in nondiabetic subjects.

BACKGROUND

Metformin prevents diabetes and may reduce coronary events in patients with diabetes, but effects on microvascular function and angina are not clear.

METHODS

We conducted an 8-week double-blind, randomized, placebo-controlled study of metformin 500 mg twice a day in 33 nondiabetic women with a prior history of normal coronary angiography but two consecutive positive (ST-segment depression > or =1 mm) exercise tolerance tests. All parameters were measured at baseline and at 8 weeks, together with an in vivo assessment of forearm (skin) microvascular function using laser Doppler imaging combined with iontophoresis.

RESULTS

In comparison with placebo (n = 17), metformin recipients (n = 16) showed significant reductions in weight and in homeostatic model assessment for insulin resistance (p < 0.05, intention to treat). Endothelium-dependent microvascular responses improved significantly with metformin (2-way repeated analysis of variance, p = 0.0003), but responses with placebo were unchanged (p = 0.50). A comparison of change in acetylcholine responses between metformin and placebo recipients was significant, whether analyzed by a 2-way analysis of variance (p < 0.0001) or change in area under curves (mean change +392 perfusion units, 95% confidence interval [CI] 20 to 764). Endothelium-independent responses were not altered. Maximal ST-segment depression (-0.84 mm, 95% CI -1.49 to -0.20, p = 0.013), Duke score (6.1 U, 95% CI 1.8 to 10.5, p = 0.008), and chest pain incidence (-0.11 episodes/day, 95% CI -0.22 to 0.00, p = 0.056) improved in metformin relative to placebo recipients.

CONCLUSIONS

Metformin may improve vascular function and decrease myocardial ischemia in nondiabetic women with chest pain and angiographically normal coronary arteries. Larger controlled trials of longer duration are warranted.

Relationship of glucose concentrations with PAI-1 and t-PA in subjects with normal glucose tolerance

AIM

To study metabolic risk factors for the development of cardiovascular disease (CVD), including markers of the fibrinolytic system in relation to blood glucose levels in subjects with normal glucose tolerance and fasting blood glucose levels below 5.6 mmol/l.

METHODS

Cross-sectional, community-based study from a primary health-care centre of adult subjects with normal glucose tolerance. Analysis of fasting and 2-h post-load blood glucose concentrations were centralized and related to anthropometric characteristics, metabolic variables, inflammatory markers, and coagulation and fibrinolytic variables.

RESULTS

Increasing fasting blood glucose concentrations within the normal range in subjects with normal glucose tolerance were associated with increasing age, body mass index, and waist circumference, and with increasing concentrations of metabolic risk factors for development of CVD. After adjustment for gender, age, body mass index (BMI), and fasting insulin, levels of plasmin activator inhibitor (PAI-1) and tissue type plasminogen activator (t-PA) increased significantly with increasing levels of fasting glucose within the normal range (P = 0.012 and P < 0.0001, respectively).

CONCLUSIONS

We found risk factors for CVD, specifically key components of the fibrinolytic system, PAI-1 and t-PA, increased with increasing fasting glucose levels even in subjects with normal glucose tolerance. This observation may help to explain the increased risk of CVD with increasing values of fasting glucose in the normal range.

Improved fibrinolysis by an intensive lifestyle intervention in subjects with impaired glucose tolerance. The Finnish Diabetes Prevention Study

AIMS/HYPOTHESIS

The aim of this study was to investigate the effects of lifestyle intervention on the levels of plasminogen activator inhibitor (PAI-1) and fibrinogen in subjects participating in the Finnish Diabetes Prevention Study (DPS).

METHODS

In five DPS centres, 321 subjects with impaired glucose tolerance (intervention group, n=163; control group, n=158) had their PAI-1 and fibrinogen levels measured at baseline and at the 1-year follow-up. Additional 3-year follow-up assessments were carried out in a sample of 97 subjects in one of the DPS centres (Turku). The intervention programme included an intensive lifestyle intervention aiming at weight reduction, healthy diet and increased physical activity.

RESULTS

During the first intervention year, PAI-1 decreased by 31% in the intervention group but showed no change in the control group (p<0.0001). In the Turku subgroup, the decrease in PAI-1 persisted throughout the 3-year follow-up. Changes in PAI-1 were associated with the number of lifestyle changes made during the first year (p=0.008). Weight reduction was the most important factor explaining the decrease in PAI-1. Changes in fibrinogen levels did not differ between the groups.

CONCLUSIONS/INTERPRETATION

In addition to the previously reported reduction in the risk of type 2 diabetes in DPS participants with impaired glucose tolerance, the intensive dietary and exercise intervention had beneficial long-term effects on fibrinolysis as indicated by the reduced levels of PAI-1. These results suggest that elevated PAI-1 levels in obese subjects with impaired glucose tolerance are mostly reversible by lifestyle changes, especially those geared to weight reduction.

Structural Requirements for Activation of Latent Platelet-derived Growth Factor CC by Tissue Plasminogen Activator

Platelet-derived growth factor C (PDGF-C) is one of four members in the PDGF family of growth factors, which are known mitogens and survival factors for cells of mesenchymal origin. PDGF-C has a unique two-domain structure consisting of an N-terminal CUB and a conserved C-terminal growth factor domain that are separated by a hinge region. PDGF-C is secreted as a latent dimeric factor (PDGF-CC), which undergoes extracellular removal of the CUB domains to become a PDGF receptor alpha agonist. Recently, the multidomain serine protease tissue plasminogen activator (tPA), a thrombolytic agent used for treatment of acute ischemic stroke, was shown to cleave and activate PDGF-CC. In this study we determine the molecular mechanism of tPA-mediated activation of PDGF-CC. Using various PDGF-CC and tPA mutants, we were able to demonstrate that both the CUB and the growth factor domains of PDGF-C, as well as the kringle-2 domain of tPA, are required for the interaction and cleavage to occur. We also show that Arg231 in PDGF-C is essential for tPA-mediated proteolysis and that the released "free" CUB domain of PDGF-C can act as a competitive inhibitor of the cleavage reaction. Furthermore, we studied how the PDGF-C/tPA axis is regulated in primary fibroblasts and found that PDGF-C expression is down-regulated by hypoxia but induced by transforming growth factor (TGF)-beta1 treatment. Elucidating the regulation and the mechanism of tPA-mediated activation of PDGF-CC will advance our knowledge of the physiological function of PDGF-CC and tPA and may provide new therapeutic opportunities for thrombolytic and cardiovascular therapies.

Cardiovascular prevention in type 2 diabetic patients: review of efficacious treatments

BACKGROUND

Type 2 diabetes (t2DM) is a chronic and complex metabolic condition requiring continuing medical care in order to reduce the risk of long-term complications. Macrovascular complications cause about 65% of deaths in subjects with t2DM and are responsible for severe co-morbidity. Many studies have addressed cardiovascular (CV) risk reduction in t2DM subjects.

OBJECTIVES

To summarise the evidence concerning the impact of lifestyle and of medical interventions in t2DM patients on CV risk (myocardial infarction, stroke, CV death, or a combination of these).

METHODS

We successively reviewed the recent guidelines addressing CV prevention in t2DM and searched the Cochrane Controlled Trials Register (CCTR), Medline & Embase to find systematic reviews and original articles on CV events in t2DM patients. We selected original studies which included solely t2DM patients or a large t2DM subgroup (n>100), tested lifestyle habits or drug treatments, and analysed CV endpoints. Their design had to be a randomised controlled trial for drug interventions, and a prospective cohort for lifestyle habits. MAIN STUDIES: We found 4 major guidelines focusing on CV prevention in t2DM patients, all released in 2003, and 10 reviews and meta-analyses: one dealing with dietary intervention, three with blood pressure lowering, one with ACE-inhibitors, one (with update) with platelet-inhibitors , three with cholesterol-inhibitors and one that dealt with both cholesterol-inhibition and blood pressure lowering. We included cohort studies on cigarette smoking (1), physical exercise (3) and weight control (1), as well as randomised trials on treatment of glycaemia (1), lipidaemia (13), blood pressure (12) and platelet aggregation (4). We also included one open randomised trial dealing with a multifactorial treatment.

CONCLUSIONS

Global CV risk management in t2DM should aim at changes in lifestyle habits and daily use of multiple drugs. Treatment should be long-term and target-driven with intensified interventions aimed at all validated targets. Lifestyle approach is of primary importance. Five targets are supported by strong clinical evidence (Table 4): reduction of blood pressure and of LDL-Cholesterol to normal values, and the use of three types of drugs which inhibit, respectively, platelet aggregation, angiotensin pathway and cholesterol synthesis.