Different metabolic correlations of thrombin-activatable fibrinolysis inhibitor and plasminogen activator inhibitor-1 in non-obese type 2 diabetic patients

Mechanisms of endothelial activation, hypercoagulation and thrombosis in COVID-19: a link with diabetes mellitus

Early since the onset of the COVID-19 pandemic, the medical and scientific community were aware of extra respiratory actions of SARS-CoV-2 infection. Endothelitis, hypercoagulation, and hypofibrinolysis were identified in COVID-19 patients as subsequent responses of endothelial dysfunction. Activation of the endothelial barrier may increase the severity of the disease and contribute to long-COVID syndrome and post-COVID sequelae. Besides, it may cause alterations in primary, secondary, and tertiary hemostasis. Importantly, these responses have been highly decisive in the evolution of infected patients also diagnosed with diabetes mellitus (DM), who showed previous endothelial dysfunction. In this review, we provide an overview of the potential triggers of endothelial activation related to COVID-19 and COVID-19 under diabetic milieu. Several mechanisms are induced by both the viral particle itself and by the subsequent immune-defensive response (i.e., NF-κB/NLRP3 inflammasome pathway, vasoactive peptides, cytokine storm, NETosis, activation of the complement system). Alterations in coagulation mediators such as factor VIII, fibrin, tissue factor, the von Willebrand factor: ADAMST-13 ratio, and the kallikrein-kinin or plasminogen-plasmin systems have been reported. Moreover, an imbalance of thrombotic and thrombolytic (tPA, PAI-I, fibrinogen) factors favors hypercoagulation and hypofibrinolysis. In the context of DM, these mechanisms can be exacerbated leading to higher loss of hemostasis. However, a series of therapeutic strategies targeting the activated endothelium such as specific antibodies or inhibitors against thrombin, key cytokines, factor X, complement system, the kallikrein-kinin system or NETosis, might represent new opportunities to address this hypercoagulable state present in COVID-19 and DM. Antidiabetics may also ameliorate endothelial dysfunction, inflammation, and platelet aggregation. By improving the microvascular pathology in COVID-19 and post-COVID subjects, the associated comorbidities and the risk of mortality could be reduced.

Quality of glycemic control in type 2 diabetes mellitus (T2DM) and its association with markers of coagulation and inhibitors of fibrinolysis: A case-control study in the Upper West Region, Ghana

Background and Aims

Type 2 diabetes mellitus (T2DM) individuals are at a higher risk of developing diabetes complications, with approximately 80% complication-related mortality. The increased morbidity and mortality among T2DM patients are partly due to dysregulated hemostasis. This study determined the quality of glycemic control in T2DM and its association with markers of coagulation and inhibitors of fibrinolysis.

Methods

This case-control study recruited 90 participants involving: 30 T2DM patients with good glycemic control, 30 with poor glycemic control, and 30 nondiabetic subjects as controls at a Municipal Hospital in Ghana. Fasting blood glucose, glycated hemoglobin, activated partial thromboplastin time (APTT), prothrombin time (PT), calculated international normalized ratio (INR), and full blood count (FBC) were determined for each respondent. Plasma levels of plasminogen activator inhibitor-1 (PAI-1) and thrombin activatable fibrinolysis inhibitor (TAFI) were determined using the solid-phase sandwich enzyme-linked immunosorbent assay method. Data were analyzed using R language software.

Results

Plasma PAI-1 antigen levels were significantly higher in the participants with poor glycemic control as compared to participants with good glycemic control (p < 0.0001). There was no significant difference in plasma TAFI levels between the participants with poor glycemic control as compared to participants with good glycemic control (p = 0.900). T2DM patients had significantly shorter APTT, PT, and INR than controls (p < 0.05). At a cut-off of ≥161.70 pg/μL, PAI was independently associated with increasing odds (adjusted odds ratio = 13.71, 95% confidence interval: 3.67-51.26, p < 0.0001) of poor glycemic control and showed the best diagnostic accuracy for poor glycemic control (area under the curve = 0.85, p < 0.0001).

Conclusion

PAI-1 levels were significantly increased in T2DM with poor glycemic control and emerged as the best predictor for poor glycemic control. Good glycemic management to control the plasma levels of PAI-1 is required to prevent hypercoagulability and thrombotic disorders.

Serum thrombin-activatable fibrinolysis inhibitor levels and its relation with pathogenesis and bleeding and prognosis in patients with Crimean Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever (CCHF) is a viral hemorrhagic fever, which is common in Turkey and globally. The pathogenesis of coagulation disorders, which is seen in viral hemorrhagic fevers remains to be elucidated. Thrombin-activatable fibrinolysis inhibitor (TAFI) has a key role in this process In this study, we aimed to evaluate whether TAFI levels contributed to bleeding and whether it is related to prognosis in CCHF patients. Eighty-four patients older than 15 years of age, who were admitted to our hospital who had positive immunoglobulin M (enzyme-linked immunosorbent assay [ELISA]) and/or polymerase chain reaction test results for CCHF between 2009 and 2010, were included in the study. The control group included 30 healthy adults. The plasma TAFI levels were compared between patients and controls, and also between patients with bleeding and no bleeding, and between patients with mild-moderate and severe disease. The mean TAFI levels were lower in patients (mean: 87.82 ng/ml, median: 61.69 ng/ml (interquartile range [IQR] 30.49-537.95) than controls (mean: 313.5 ng/ml with a median: 338.5 ng/ml (IQR 182-418). However, median TAFI levels were significantly higher in patients with bleeding compared to those without bleeding (78.99 and 50.28 ng/ml, respectively; p = 0.032). Median IQR TAFI levels were similar between patients with mild-moderate and severe disease (64.72 (41.37-113.85), and, 58.66 (42.44-118.93) ng/ml, respectively; p = 0.09) and survivors and nonsurvivors (86.14 ± 77.98 and 103.48 ± 69.92, respectively; p = 0.3). Although TAFI levels were lower in the patients with CCHF compared to healthy controls, it does not seem to be a major player in the prognosis.

Hyperglycaemia and the risk of post-surgical adhesion

Post-surgical adhesions are a major complication leading to organ dysfunctions, pain, intestinal obstruction, and infertility. The incidence of post-surgical adhesion is really high. The factors involved in the pathogenesis of post-surgical fibrosis, are largely unknown, for example why two patients with similar abdominal operation have a different risks of adhesion severity? High secretion of pro-inflammatory cytokines and growth factors, includes tumour necrosis factor α (TNF-α), interleukin 6 (IL6), and transforming growth factor β (TGF-β) by persistent recruitment of immune cells and the inappropriate proliferated fibroblast/mesothelial cells can stimulate signalling pathways particularly TGF-β leads to the up-regulation of some pro-fibrotic genes that impair fibrinolytic activity and promote extracellular matrix (ECM) accumulation. In this review, we focus on the role of diabetes and hyperglycaemia on post-surgical fibrosis, including the molecular mechanisms affected by hyperglycaemia that cause inflammation, oxidative stress, and increase the expression of pro-fibrotic molecules.

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.

PAI-1 in Diabetes: Pathophysiology and Role as a Therapeutic Target

Hypofibrinolysis is a key abnormality in diabetes and contributes to the adverse vascular outcome in this population. Plasminogen activator inhibitor (PAI)-1 is an important regulator of the fibrinolytic process and levels of this antifibrinolytic protein are elevated in diabetes and insulin resistant states. This review describes both the physiological and pathological role of PAI-1 in health and disease, focusing on the mechanism of action as well as protein abnormalities in vascular disease with special focus on diabetes. Attempts at inhibiting protein function, using different techniques, are also discussed including direct and indirect interference with production as well as inhibition of protein function. Developing PAI-1 inhibitors represents an alternative approach to managing hypofibrinolysis by targeting the pathological abnormality rather than current practice that relies on profound inhibition of the cellular and/or acellular arms of coagulation, and which can be associated with increased bleeding events. The review offers up-to-date knowledge on the mechanisms of action of PAI-1 together with the role of altering protein function to improve hypofirbinolysis. Developing PAI-1 inhibitors may form for the basis of future new class of antithrombotic agents that reduce vascular complications in diabetes.

Carboxypeptidase U (CPU, TAFIa, CPB2) in Thromboembolic Disease: What Do We Know Three Decades after Its Discovery?

Procarboxypeptidase U (proCPU, TAFI, proCPB2) is a basic carboxypeptidase zymogen that is converted by thrombin(-thrombomodulin) or plasmin into the active carboxypeptidase U (CPU, TAFIa, CPB2), a potent attenuator of fibrinolysis. As CPU forms a molecular link between coagulation and fibrinolysis, the development of CPU inhibitors as profibrinolytic agents constitutes an attractive new concept to improve endogenous fibrinolysis or to increase the efficacy of thrombolytic therapy in thromboembolic diseases. Furthermore, extensive research has been conducted on the in vivo role of CPU in (the acute phase of) thromboembolic disease, as well as on the hypothesis that high proCPU levels and the Thr/Ile325 polymorphism may cause a thrombotic predisposition. In this paper, an overview is given of the methods available for measuring proCPU, CPU, and inactivated CPU (CPUi), together with a summary of the clinical data generated so far, ranging from the current knowledge on proCPU concentrations and polymorphisms as potential thromboembolic risk factors to the positioning of different CPU forms (proCPU, CPU, and CPUi) as diagnostic markers for thromboembolic disease, and the potential benefit of pharmacological inhibition of the CPU pathway.

Hemostasis in Hypothyroidism and Autoimmune Thyroid Disorders

CONTEXT

There are contradictory results on the effect of hypothyroidism on the changes in hemostasis. Inadequate population-based studies limited their clinical implications, mainly on the risk of venous thromboembolism (VTE). This paper reviews the studies on laboratory and population-based findings regarding hemostatic changes and risk of VTE in hypothyroidism and autoimmune thyroid disorders.

EVIDENCE ACQUISITION

A comprehensive literature search was conducted employing MEDLINE database. The following words were used for the search: Hypothyroidism; thyroiditis, autoimmune; blood coagulation factors; blood coagulation tests; hemostasis, blood coagulation disorders; thyroid hormones; myxedema; venous thromboembolism; fibrinolysis, receptors thyroid hormone. The papers that were related to hypothyroidism and autoimmune thyroid disorder and hemostasis are used in this review.

RESULTS

Overt hypothyroidism is more associated with a hypocoagulable state. Decreased platelet count, aggregation and agglutination, von Willebrand factor antigen and activity, several coagulation factors such as factor VIII, IX, XI, VII, and plasminogen activator-1 are detected in overt hypothyrodism. Increased fibrinogen has been detected in subclinical hypothyroidism and autoimmune thyroid disease rendering a tendency towards a hypercoagulability state. Increased factor VII and its activity, and plasminogen activator inhibitor-1 are among several findings contributing to a prothrombotic state in subclinical hypothyroidism.

CONCLUSIONS

Overt hypothyroidism is associated with a hypocoagulable state and subclinical hypothyroidism and autoimmune thyroid disorders may induce a prothrombotic state. However, there are contradictory findings for the abovementioned thyroid disorders. Prospective studies on the risk of VTE in various levels of hypofunctioning of the thyroid and autoimmune thyroid disorders are warranted.

Stability and Species Specificity of Renal VEGF-A Splicing Patterns in Kidney Disease

Vascular endothelial growth factor A (VEGF-A) is essential for maintaining the glomerular filtration barrier. Absolute renal levels of VEGF-A change in patients with diabetic nephropathy and inflammatory kidney diseases, but whether changes in the renal splicing patterns of VEGF-A play a role remains unclear. In this study, we investigated mRNA splicing patterns of pro-angiogenic isoforms of VEGF-A in glomeruli and whole kidney samples from human patients with kidney disease and from mouse models of kidney disease. Kidney biopsies were obtained from patients with acute rejection following kidney transplantation, patients with diabetic nephropathy, and control subjects. In addition, kidney samples were obtained from mice with lupus nephritis, mice with diabetes mellitus, and control mice. The relative expression of each VEGF-A splice variant was measured using RT-PCR followed by quantitative fragment analysis. The pattern of renal VEGF-A splice variants was unchanged in diabetic nephropathy and lupus nephritis and was stable throughout disease progression in acute transplant rejection and diabetic nephropathy; these results suggest renal VEGF-A splicing stability during kidney disease. The splicing patterns were species-specific; in the control human kidney samples, VEGF-A 121 was the dominant isoform, whereas VEGF-A 164 was the dominant isoform measured in the mouse kidney samples.

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.

Leptin and resistin induce increased procoagulability in diabetes mellitus

BACKGROUND

Patients with diabetes mellitus (DM) suffer from an increased risk of cardiovascular events caused by thrombotic conditions. Adipose tissue might play a crucial role in this pathogenesis by synthesis of procoagulant mediators. This study was performed to elucidate the role of the adipocytokines leptin and resistin in the development of hypercoagulability and hypofibrinolysis under diabetic conditions.

METHODS

Sixty two patients with or without DM were included in our study to measure leptin, resistin and tissue factor (TF) plasma concentrations. Moreover, flow chamber experiments were performed to assess factor Xa and plasmin activity on the surface of HUVECs. Western blot and real-time PCR were performed to determine mRNA and protein expression of main factors of the coagulation and fibrinolytic system.

RESULTS

Patients with diabetes showed increased levels of leptin and resistin (leptin: 25.69±13.9 vs. 15.98±17.5 ng/mL, p<0.05; resistin: 2.61±0.6 vs. 1.19±0.7 ng/mL, p<0.05), which were positively correlated with TF. In vitro, leptin and resistin induced increased factor Xa activity (leptin: 4.29±0.57-fold, p<0.05; resistin 4.19±0.7-fold, p<0.05 vs. control) on HUVECs as also reflected by elevated TF mRNA and protein expression. Moreover, stimulatory (plasminogen activator inhibitor 1) and inhibitory (tissue plasminogen activator) mediators of the fibrinolytic cascade were induced by leptin and resistin, leading to a balanced plasmin activity regulation.

CONCLUSIONS

Leptin and resistin lead to a procoagulant state in HUVECs by inducing TF expression. This mechanism might be one explanation for the prothrombotic state observed under diabetic conditions.

The role of thrombin-activatable fibrinolysis inhibitor in diabetic wound healing

INTRODUCTION

One of the major complications in patients with diabetes mellitus is impaired wound healing. The fibrinolytic system is involved in parts of the wound healing process and deficiency of thrombin-activatable fibrinolysis inhibitor (TAFI) results in delayed wound closure. Moreover, levels of TAFI are affected by diabetes mellitus. The aim of this study was to elucidate the effect of hyperglycaemia on TAFI and to determine the effect of deficiency of TAFI on wound healing under hyperglycaemic conditions.

MATERIALS AND METHODS

Hyperglycaemia was induced with streptozotocin (STZ) and used as a model for diabetes mellitus. TAFI plasma levels and TAFI gene expression in the liver were determined. Incisional and excisional wound healing were studied in non-treated and STZ-treated wild-type and TAFI-deficient mice. Wound closure was scored daily as open or closed.

RESULTS

Mice treated with STZ showed hyperglycaemia, and TAFI plasma levels and TAFI gene expression were increased in diabetic mice. TAFI-deficient mice and diabetic wild-type and diabetic TAFI-deficient mice showed delayed wound healing of incisional wounds. No differences were observed between diabetic and non-diabetic TAFI-deficient mice and between diabetic wild-type and diabetic TAFI-deficient mice.

CONCLUSIONS

This study illustrated that TAFI was affected by hyperglycaemia and confirmed that TAFI is involved in wound healing. No additional effect was observed under hyperglycaemic conditions, indicating that deficiency of TAFI did not have an additive or synergistic effect in diabetic wound healing. Further research has to elucidate if TAFI and hyperglycemia affect wound healing via similar mechanisms.

Analysis of a new crystal form of procarboxypeptidase B: further insights into the catalytic mechanism

A new triclinic crystal structure form of porcine pancreatic procarboxypeptidase B (PCPB) was obtained at higher resolution than the previously known tetragonal crystal structure. This new crystal polymorph has allowed for a corrected, accurate assignment of residues along the polypeptide chain based on the currently available gene sequence information and crystallographic data. The present structure shows unbound PCPB in a distinct molecular packing as compared to the previous benzamidine complexed form. Its catalytically important Tyr248 residue is oriented and hydrogen-bonded to solvent water molecules, and locates the furthest away from the catalytic zinc ion as compared to previous structures. A relatively long stretch of residues flanking Tyr248 and guarding the access to the catalytic zinc ion was found to be sequentially unique to the M14 family of peptidases. Predictions from a normal mode analysis indicated that this stretch of residues belongs to a rigid subdomain in the protein structure. The specific presence of a tyrosyl residue at the most exposed position in this region would allow for a delicate balance between extreme hydrophobicity and hydrophilicity, and affect substrate binding and the kinetic efficiency of the enzyme.

Thrombin-Activatable Fibrinolysis Inhibitor (TAFI) Antigen and Activity Assay in Patients With Primary Hypothyroidism

Hypothyroidism causes a tendency for cardiovascular diseases. It was recently shown that thrombin-activatable fibrinolysis inhibitor (TAFI) attenuates fibrinolysis and also fibrin-plasminogen interaction by the removal of lysine and arginine residues from fibrin monomers. The aim of this study was to determine the effects of overt hypothyroidism on the levels of TAFI antigen (TAFI Ag) and TAFI activity (TAFIa). Thirty-one overt primary hypothyroid patients and age- and gender-matched 25 healthy controls were enrolled in the study. Patients were treated with L-thyroxine after the collection of blood samples. Thyroid functions were reevaluated following the achievement of euthyroid status. Thrombin-activatable fibrinolysis inhibitor Ag, tissue plasminogen activator (t-PA), and plasminogen activator inhibitor 1 (PAI-1) levels were measured with the enzyme-linked immunosorbent assay (ELISA). Thrombin-activatable fibrinolysis inhibitor activity was assessed with the chromogenic assay. Thrombin-activatable fibrinolysis inhibitor Ag (1.63% ± 0.42% vs 1.32% ± 0.36%, P < .01) and TAFIa (14.2 ± 4.12 vs 11.6 ± 3.49 μg/mL, P < .05) levels were elevated in hypothyroid patient compared to controls. Plasminogen activator inhibitor 1 and t-PA levels were not significantly different between both groups. In hypothyroid patients, TAFI Ag levels were correlated with free T4 (r = -.373, P < .05) and thyroid-stimulating hormone (TSH) levels (r = .748, P < .001). Regression analysis showed that TSH levels were predictors of TAFI Ag levels (P < .001, β =.671, 95% confidence interval [CI]: 0.008-0.017). Following L-thyroxine treatment, TAFI Ag (1.63% ± 0.42%, 1.34% ± 0.33%, P < .05) and TAFIa (14.2 ± 4.12 μg/mL, 12.0 ± 2.77 μg/mL, P < .05) levels were significantly decreased, but t-PA and PAI-1 levels remained unchanged. This results point out that the fibrinolytic activity was decreased in hypothyroid patients, and therefore the achievement of euthyroid status is important in ameliorating the increased risk of cardiovascular disease.

The X-ray structure of carboxypeptidase A inhibited by a thiirane mechanism-based inhibitor

The three-dimensional X-ray crystal structure of carboxypeptidase A, a zinc-dependent hydrolase, covalently modified by a mechanism-based thiirane inactivator, 2-benzyl-3,4-epithiobutanoic acid, has been solved to 1.38 A resolution. The interaction of the thiirane moiety of the inhibitor with the active site zinc ion promotes its covalent modification of Glu-270 with the attendant opening of the thiirane ring. The crystal structure determination at high resolution allowed for the clear visualization of the covalent ester bond to the glutamate side chain. The newly generated thiol from the inhibitor binds to the catalytic zinc ion in a monodentate manner, inducing a change in the zinc ion geometry and coordination, while its benzyl group fits into the S1' specificity pocket of the enzyme. The inhibitor molecule is distorted at the position of the carbon atom that is involved in the ester bond linkage on one side and the zinc coordination on the other. This particular type of thiirane-based metalloprotease inhibitor is for the first time analyzed in complex to the target protease at high resolution and may be used as a general model for zinc-dependent proteases.

Role of adipose tissue in haemostasis, coagulation and fibrinolysis

Obesity is associated with an increased incidence of insulin resistance (IR), type 2 diabetes mellitus and cardiovascular diseases. The increased risk for cardiovascular diseases could partly be caused by a prothrombotic state that exists because of abdominal obesity. Adipose tissue induces thrombocyte activation by the production of adipose tissue-derived hormones, often called adipokines, of which some such as leptin and adiponectin have been shown to directly interfere with platelet function. Increased adipose tissue mass induces IR and systemic low-grade inflammation, also affecting platelet function. It has been demonstrated that adipose tissue directly impairs fibrinolysis by the production of plasminogen activator inhibitor-1 and possibly thrombin-activatable fibrinolysis inhibitor. Adipose tissue may contribute to enhanced coagulation by direct tissue factor production, but hypercoagulability is likely to be primarily caused by affecting hepatic synthesis of the coagulation factors fibrinogen, factor VII, factor VIII and tissue factor, by releasing free fatty acids and pro-inflammatory cytokines (tumour necrosis factor-alpha, interleukin-1beta and interleukin-6) into the portal circulation and by inducing hepatic IR. Adipose tissue dysfunction could thus play a causal role in the prothrombotic state observed in obesity, by directly and indirectly affecting haemostasis, coagulation and fibrinolysis.

Thrombin activatable fibrinolysis inhibitor and other hemostatic parameters in patients with polycystic ovary syndrome

OBJECTIVES

To investigate the plasma levels of thrombin-activatable fibrinolysis inhibitor (TAFI) in women with polycystic ovary syndrome (PCOS) and its correlation with various metabolic, hormonal and hemostatic parameters.

METHODS

Forty-eight women with PCOS and 43 age- and BMI-matched ovulatory controls were recruited during a 20-month study period. Blood samples were drawn for all tests, which included plasma lipids and lipoproteins, reproductive hormones, glucose, insulin, TAFI antigen concentration, plasminogen activator inhibitor-1 (PAI-1) activity, fibrinogen concentration, thrombomodulin, thrombin-antithrombin (TAT) complexes, D-dimer, Protein C Antigen, Protein S Antigen, Antithrombin III (AT III) and activated protein C (APC) resistance.

RESULTS

Plasma TAFI levels of PCOS patients were found to be significantly higher than in healthy controls (93.8%+/-30.6%vs. 79.8% +/- 22.4%, p < 0.05). Plasma levels of D-dimer, AT III, PAI-1 and thrombomodulin were also significantly higher in women with PCOS compared with healthy controls. All the other hemostatic parameters (including TAT complexes; Protein C; APC; and Protein S) were comparable between the two study groups.

CONCLUSION

This study showed that plasma levels of TAFI, PAI-1, D-dimer, AT III and thrombomodulin were significantly increased in women with PCOS compared with age- and BMI-matched controls.

Gestational diabetes has no additional effect on plasma thrombin-activatable fibrinolysis inhibitor antigen levels beyond pregnancy

Pregnancy is a prothrombotic condition with increased levels of several circulating coagulation factors. Decreased fibrinolytic activity has been shown in gestational diabetes. Gestational diabetes has been found to be associated with higher plasma plasminogen activator inhibitor-1 (PAI-1) antigen levels than normal pregnancy. The aim of the present study is to investigate the effect of gestational diabetes on plasma thrombin-activatable fibrinolysis inhibitor (TAFI) antigen levels. Plasma TAFI and PAI-1 antigen levels were measured in 26 pregnant women with gestational diabetes, 25 pregnant women with normal glucose tolerance, and age-matched 24 non-pregnant women with no history of gestational diabetes. Increased plasma TAFI antigen levels were found in pregnant women compared to non-pregnant controls. However, no statistically significant difference in TAFI antigen levels was observed between women with gestational diabetes and pregnant controls. Plasma PAI-1 antigen levels were higher in gestational diabetes than pregnant and non-pregnant controls. Our study revealed that pregnancy was associated with elevated plasma TAFI antigen levels. However, no additional effect of gestational diabetes was found on plasma TAFI antigen levels beyond pregnancy. We suggest that pregnancy is associated with enhanced coagulation and impaired fibrinolysis. Despite increased PAI-1 antigen levels associated with gestational diabetes, the effect of gestational diabetes on TAFI antigen levels is lacking.

Plasminogen activator inhibitor-1 and thrombin activatable fibrinolysis inhibitor levels in non-alcoholic steatohepatitis

AIM

This study was conducted to demonstrate the plasminogen activator inhibitor- 1 (PAI-1) and thrombin activatable fibrinolysis inhibitor antigen (TAFI-Ag) levels in non-alcoholic steatohepatitis (NASH).

MATERIALS AND METHODS

Twenty-seven patients with biopsy-proven NASH and 18 healthy controls (HC) were recruited for the study. Anthropometric data, liver histology (no.=20) and laboratory parameters including PAI-1 and TAFI-Ag assessments were recorded.

RESULTS

When compared with HC, patients with NASH had higher body weight, higher waist circumference, elevated blood pressure, higher fasting plasma glucose (FPG) levels and higher homeostasis model assessment (HOMA) scores. The mean plasma PAI-1 levels of patients was found to be higher than HC (87.60 ng/ml vs 30.84 ng/ml p=0.000) and mean plasma TAFI-Ag levels of patients was found to be significantly lower (8.69 microg/ml vs 12.19 microg/ml p=0.000). PAI-1 levels were correlated with systolic blood pressure, age, body weight, transaminases, waist circumference, FPG, body mass index, and HOMA score. TAFI-Ag levels were found to be negatively correlated with transaminases, waist circumference, and body weight. In multiple regression analysis, BMI was the independent variable effecting PAI-1 levels. We did not show any association between PAI-1, TAFI-Ag, disease activity score and fibrosis score. HOMA was the independent variable effecting liver fibrosis in our patients.

CONCLUSION

In this study we demonstrated that patients with biopsy-proven NASH had higher PAI-1 and lower TAFI-Ag expression than HC. Elevated levels of PAI-1 in NASH is the consequence of insulin resistance state. Lower TAFI-Ag levels may be related to the overactivation of TAFI pathway resulting in TAFI-Ag depletion. Furthermore, liver function disturbances may impair TAFI production in NASH. We also showed that NASH patients even with slight elevations of transaminases feature marked insulin resistance and components of metabolic syndrome.

Thrombin activatable fibrinolysis inhibitor antigen levels are inversely correlated with plasminogen activator inhibitor-1 antigen levels in hyperthyroid patients

Both increased and decreased fibrinolytic activity have been reported in patients with hyperthyroidism. Elevated levels of plasma plasminogen activator inhibitor-1 (PAI-1) antigen have been found in hyperthyroid patients. Thrombin activatable fibrinolysis inhibitor (TAFI) is a novel plasma protein, which inhibits fibrinolysis through removal of C-terminal lysines from partially degraded fibrin. Previously, we showed that plasma TAFI antigen levels were increased in patients with overt and subclinical hypothyroidism. The aim of this study is to investigate plasma levels of TAFI and PAI-1 antigens in hyperthyroid patients. PAI-1 and TAFI antigen levels were measured in the plasma of 29 patients with hyperthyroidism (14 overt hyperthyroid and 15 subclinical hyperthyroid), and 26 healthy individuals. Although there were increased levels of PAI-1 antigen in hyperthyroid patients, plasma TAFI antigen levels were significantly lower compared to controls (80.79 ng/ml vs. 32.42 ng/ml, p = 0.000 for PAI-1; 10.42 microg/ml vs. 12.24 microg/ml, p = 0.009 for TAFI). Elevated PAI-1 antigen levels were positively correlated with free thyroid hormones, although TAFI antigen levels were in negative correlation with free thyroxine. Furthermore, an inverse correlation between PAI-1 and TAFI antigen levels was found. Our study demonstrated that TAFI antigen levels were decreased in patients with hyperthyroidism. Inverse correlation with PAI-1 suggests that the decrease in TAFI antigen levels may be due to activation of TAFI pathway. Further studies evaluating the underlying mechanisms of low TAFI antigen levels in hyperthyroidism should be undertaken.