Thrombomodulin and induced tissue factor expression on monocytes as markers of diabetic microangiopathy: a prospective study on hemostasis and lipoproteins in insulin-dependent diabetes mellitus

Minireview: Understanding and targeting inflammatory, hemodynamic and injury markers for cardiorenal protection in type 1 diabetes

The coexistence of cardiovascular disease (CVD) and diabetic kidney disease (DKD) is common in people with type 1 diabetes (T1D) and is strongly associated with an increased risk of morbidity and mortality. Hence, it is imperative to explore robust tools that can accurately reflect the development and progression of cardiorenal complications. Several cardiovascular and kidney biomarkers have been identified to detect at-risk individuals with T1D. The primary aim of this review is to highlight biomarkers of injury, inflammation, or renal hemodynamic changes that may influence T1D susceptibility to CVD and DKD. We will also examine the impact of approved pharmacotherapies for type 2 diabetes, including renin-angiotensin-aldosterone system (RAAS) inhibitors, sodium-glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1RAs) on candidate biomarkers for cardiorenal complications in people with T1D and discuss how these changes may potentially mediate kidney and cardiovascular protection. Identifying predictive and prognostic biomarkers for DKD and CVD may highlight potential drug targets to attenuate cardiorenal disease progression, implement novel risk stratification measures in clinical trials, and improve the assessment, diagnosis, and treatment of at-risk individuals with T1D.

Type 1 Diabetes Mellitus in the SARS-CoV-2 Pandemic: Oxidative Stress as a Major Pathophysiological Mechanism Linked to Adverse Clinical Outcomes

Recent reports have demonstrated the association between type 1 diabetes mellitus (T1DM) and increased morbidity and mortality rates during coronavirus disease (COVID-19) infection, setting a priority of these patients for vaccination. Impaired innate and adaptive immunity observed in T1DM seem to play a major role. Severe, life-threatening COVID-19 disease is characterized by the excessive release of pro-inflammatory cytokines, known as a "cytokine storm". Patients with T1DM present elevated levels of cytokines including interleukin-1a (IL), IL-1β, IL-2, IL-6 and tumor necrosis factor alpha (TNF-α), suggesting the pre-existence of chronic inflammation, which, in turn, has been considered the major risk factor of adverse COVID-19 outcomes in many cohorts. Even more importantly, oxidative stress is a key player in COVID-19 pathogenesis and determines disease severity. It is well-known that extreme glucose excursions, the prominent feature of T1DM, are a potent mediator of oxidative stress through several pathways including the activation of protein kinase C (PKC) and the increased production of advanced glycation end products (AGEs). Additionally, chronic endothelial dysfunction and the hypercoagulant state observed in T1DM, in combination with the direct damage of endothelial cells by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), may result in endothelial and microcirculation impairment, which contribute to the pathogenesis of acute respiratory syndrome and multi-organ failure. The binding of SARS-CoV-2 to angiotensin converting enzyme 2 (ACE2) receptors in pancreatic b-cells permits the direct destruction of b-cells, which contributes to the development of new-onset diabetes and the induction of diabetic ketoacidosis (DKA) in patients with T1DM. Large clinical studies are required to clarify the exact pathways through which T1DM results in worse COVID-19 outcomes.

Effect of type 1 diabetes and type 2 diabetes on the risk of venous thromboembolism

AIMS

Whether diabetes increases venous thromboembolism (VTE) is unclear. Any greater risk may relate to insulin resistance, but many studies did not differentiate between type 1 diabetes and type 2 diabetes for VTE risk.

METHODS

Retrospective cohort study of the Royal College of General Practitioners Research and Surveillance Centre, comprising over 530 primary care practices. We determined whether type 1 diabetes and/or type 2 diabetes are independent risk factors for VTE. The index date was 1 January 2009, individuals were followed to 31 December 2018, or censoring. Cox proportional hazard regression analysis was used to investigate the risk of VTE in people with type 1 diabetes and type 2 diabetes relative to no diabetes. The primary outcome was occurrence of VTE. The model was adjusted for potential confounders for VTE.

RESULTS

There were 7086 people with type 1 diabetes and 95,566 with type 2 diabetes, diagnosed before 1 January 2009. The non-diabetes group consisted of 1,407,699 people. In the unadjusted analysis, there was no increased risk of VTE with type 1 diabetes (HR 1.00, 95% CI 0.76-1.33) but there was for type 2 diabetes (HR 2.70, 95% CI 2.57-2.84). In the fully adjusted model, VTE risk was increased in type 1 diabetes (HR 1.46, 95% CI 1.11-1.92), but not with type 2 diabetes (HR 1.06, 95% CI 0.98-1.14).

CONCLUSIONS

Type 1 diabetes was associated with a greater risk for VTE while type 2 diabetes was not. Further work is needed to determine the reason(s) for this.

Increased tissue factor activity promotes thrombin generation at type 1 diabetes onset in children

OBJECTIVE

In type 1 diabetes (T1D), a prothrombotic status due to elevated coagulation factors coincides with metabolic derailment. In a previous study, we discovered altered thrombin generation profiles in children with T1D. These alterations are potentially most pronounced at T1D onset and ameliorated after insulin treatment. We tested this hypothesis in a longitudinal study, measuring thrombin generation together with coagulation parameters in children at T1D onset and during follow-up.

MATERIALS AND METHODS

Twenty-three children (12 female, age: 9.4 [2.7-17.3] years; median [range]) were tested at T1D onset and after long-term insulin treatment. Thrombin generation was measured using calibrated automated thrombography. Tissue factor (TF) activity and tissue factor pathway inhibitor (TFPI) activity were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

A procoagulant shift was observed in thrombin generation traces at T1D onset compared to follow-up (time to peak: 5.67 [4.11-7.67] min vs 6.39 [4.89-10.44] min, P < .001). These alterations at T1D onset coincided with increased TF activity (5.18 [0.01-12.97] pmol/L vs 2.67 [0.04-10.41] pmol/L, P < .05) and increased TFPI activity (0.051 [0.038-0.074] U/mL vs 0.035 [0.026-0.056] U/mL, P < .05).

CONCLUSION

The procoagulant shift in thrombin generation at T1D onset is a result of increased TF activity, but this effect is partially counterbalanced by increased TFPI levels. Elevated TF and TFPI levels hint to a fragile hemostatic balance at the endothelial lining of blood vessels. Additional prothrombotic stimuli may tip over this balance explaining the increased thrombotic risk of children with T1D.

Coagulatory Defects in Type-1 and Type-2 Diabetes

Diabetes (both type-1 and type-2) affects millions of individuals worldwide. A major cause of death for individuals with diabetes is cardiovascular diseases, in part since both types of diabetes lead to physiological changes that affect haemostasis. Those changes include altered concentrations of coagulatory proteins, hyper-activation of platelets, changes in metal ion homeostasis, alterations in lipid metabolism (leading to lipotoxicity in the heart and atherosclerosis), the presence of pro-coagulatory microparticles and endothelial dysfunction. In this review, we explore the different mechanisms by which diabetes leads to an increased risk of developing coagulatory disorders and how this differs between type-1 and type-2 diabetes.

Clinical usefulness of videocapillaroscopy and selected endothelial cell activation markers in people with Type 1 diabetes mellitus complicated by microangiopathy

PURPOSE

Microvascular abnormalities are one of the most important causes of persistent diabetic complications. The aim of our study was to compare microvascular changes examined by nailfold videocapillaroscopy (NVC) examination with serum concentrations of vascular endothelial growth factor (VEGF), soluble thrombomodulin (sTM) and endothelin-1 (ET-1) in people with Type 1 diabetes with and without microangiopathy.

MATERIAL/METHODS

The study included 106 people with Type 1 diabetes and 40 healthy controls. All participants were evaluated by extensive clinical, laboratory and capillaroscopic studies. NVC was performed using a stereomicroscope SZ 4045 (Olympus, Germany). The intensity of morphological changes was graded from 0 to 3. Serum levels of VEGF, sTM and ET-1 were determined by an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Morphological changes were observed by NVC in 86 out of 106 (81%) people with Type 1 diabetes mellitus. Severe capillaroscopic changes (score 3) were seen in 32 out of 54 (59%) people with microangiopathy, but in only seven out of 52 (13%) individuals without microangiopathy. Higher serum concentration of VEGF (p<0.001), ET-1 (p<0.001) and sTM (p<0.05) were demonstrated in people with diabetes complicated with microangiopathy compared to healthy controls. Moreover, comparison between people with and without microangiopathic complications showed a significantly higher capillaroscopic score and sTM serum concentration in the group with retinopathy (p<0.001) nephropathy (p<0.001) and neuropathy (p<0.01).

CONCLUSIONS

Our results suggest that abnormalities in NVC may reflect the extent of microvascular involvement and associated with higher VEGF, sTM and ET-1 serum levels, as well as with microangiopathic complications in diabetic people.

Treatment with high-dose n-3 PUFAs has no effect on platelet function, coagulation, metabolic status or inflammation in patients with atherosclerosis and type 2 diabetes

BACKGROUND

Despite numerous studies on cardioprotective effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs), there is limited evidence for n-3 PUFA-mediated effects, especially at its higher dose, on cardiovascular risk in patients with type 2 diabetes (DM2) and established atherosclerosis.

PURPOSE

To investigate the effect of daily treatment with a higher dose (2 g) of n-3 PUFAs on platelet function, coagulation parameters, fibrin clot properties, markers of systemic inflammation and metabolic status, in patients with atherosclerotic vascular disease and DM2 who receive optimal medical therapy.

METHODS

We conducted a prospective, double-blind, placebo-controlled, randomized, double-center study, in which thrombin generation (plasma thrombogenic potential from automated thrombogram), fibrin clot properties (plasma fibrin clot permeability; lysis time), platelet aggregation (light transmission aggregometry with adenosine diphosphate and arachidonic acid used as agonists), HbA1c, insulin level, lipid profiles, leptin and adiponectin levels, as well as markers of systemic inflammation (i.e., hsCRP, IL-6, TNF-α, ICAM-1, VCAM-1, and myeloperoxidase) were determined at baseline and at 3 months after treatment with 2 g/day of n-3 PUFAs (n = 36) or placebo (n = 38). Moreover, we assessed serum fatty acids of the phospholipid fraction by gas chromatography both at baseline and at the end of the study.

RESULTS

Majority of patients were treated with optimal medical therapy and achieved recommended treatment targets. Despite higher serum levels of eicosapentaenoic acid (EPA) (by 204%; p < 0.001) and docosahexaenoic acid (DHA) (by 62%; p < 0.0001) in n-3 PUFA group at the end of treatment no changes in platelet aggregation, thrombin generation, fibrin clot properties or markers of systemic inflammation were observed. No intergroup differences in the insulin, HbA1c and lipid levels were found at the end of the study. There was no change in adiponectin and leptin in interventional group, however leptin increased in control group (p = 0.01), therefore after study period leptin levels were lower in the interventional group (p = 0.01). Additionally, resolvin D1 did not differ between interventional and control group.

CONCLUSIONS

In conclusion, our study demonstrated that in patients with long-standing, well-controlled DM2 and atherosclerotic disease the treatment with a high dose of n-3 PUFAs (namely, 1 g/day of EPA and 1 g/day of DHA for 3 months) does not improve coagulation, metabolic, and inflammatory status when measured with the specified tests. The study was registered in ClinicalTrials.gov; identifier: NCT02178501. Registration date: April 12, 2014.

Evaluation of Coagulation Profile in Children with Type 1 Diabetes Mellitus Using Rotational Thromboelastometry

The prothrombotic state in type 1 diabetes mellitus (T1DM) has been reported as a plausible cause of vascular complications. Rotational thromboelastometry (ROTEM) assay enables the global assessment of coagulation status. This study aimed to assess hypercoagulability in children with T1DM using ROTEM. A total of 43 T1DM children (20 females and 23 males) aged 2-18 years and age- and sex-matched 30 healthy control subjects were enrolled in the study group. ROTEM assays [intrinsic TEM (INTEM) and extrinsic TEM (EXTEM)] were used to measure and analyze coagulation time (CT), clot formation time, maximum clot firmness (MCF). Glycated hemoglobin levels (HbA1c), diabetic complications, platelet count, prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, and dimerized plasmin fragment D (D-dimer) were determined in the study group. The mean duration of T1DM diagnosis was 3.15 ± 2.49 years, and the mean HbA1c level was 8.94 ± 1.88% (74.29 ± 20.59 mmol/mol). None of the patients had macrovascular complications. Nephropathy was present in five patients. In the T1DM group, EXTEM-CT [80.00 (66.75-108.50)] was significantly lower, and EXTEM-MCF [65.00 (64.00-70.00)] and INTEM-MCF [65.00 (62.00-68.00)] were significantly higher than in the controls (p < 0.001, p = 0.026, and p = 0.004, respectively). However, the duration of T1DM and the degree of metabolic control had no influence on these parameters. Platelet count, PT, aPTT, fibrinogen and D-dimer levels were comparable between the diabetic patients and the control group. There were statistically significant correlations between fibrinogen level and INTEM-MCF and EXTEM-MCF (p < 0.001, p = 0.002 and r = 0.545, r = 0.454, respectively) This study shows that decreased levels of CT and increased levels of MCF suggest hypercoagulability in patients with T1DM. Further studies are needed to confirm our findings on a larger number of diabetic patients.

Effect of circulating tissue factor on hypercoagulability in type 2 diabetes mellitus studied by rheometry and dielectric blood coagulometry

BACKGROUND

Hypercoagulability in type 2 diabetes mellitus (T2DM) patients increases their risk of cardiovascular diseases.

OBJECTIVE

The aim of this work was to investigate the hypercoagulation mechanism in T2DM patients in terms of circulating tissue factor (TF).

METHODS

Whole blood coagulation tests by damped oscillation rheometry and dielectric blood coagulometry (DBCM) were performed.

RESULTS

The average coagulation time was significantly shorter for T2DM patients than for healthy controls. In vitro addition of either anti-TF or anti-activated factor VII (FVIIa) antibody to hypercoagulable blood samples prolonged coagulation times for one group of patients, while coagulation times remained short for another group. The levels of circulating TF were estimated in the former group by measuring the coagulation times for blood samples from healthy subjects with addition of various concentrations of TF and comparing them with the coagulation times for the group. The results indicated that the levels of circulating TF were on the order of subpicomolar at most.

CONCLUSIONS

Circulating TF is at least partially responsible for a hypercoagulable group of T2DM patients, while an abnormality in the intrinsic coagulation pathway probably occurs in the other group.

Novel Dielectric Coagulometer Identifies Hypercoagulability in Patients with a High CHADS2 Score without Atrial Fibrillation

Background

Recent reports showed that the CHADS₂ score predicted the risk of strokes in patients without atrial fibrillation (AF). Although the hypercoagulability may contribute to the thrombogenesis, it has not been fully investigated due to a lack of a sensitive evaluation modality. Recently a novel dielectric blood coagulometry (DBCM) was invented for evaluating the coagulability by measuring the temporal change in whole blood dielectric permittivity.

Objective

We evaluated the utility of the DBCM for identifying the coagulability.

Patients/Methods

For fundamental experiments, 133 citrated blood samples were drawn from subjects with or without heparin administration. A DBCM analysis was performed to find the adequate coagulation index, and to delineate its measurement range by adding recombinant human tissue factor (TF) or heparin. Then the coagulability was assessed by DBCM and conventional coagulation assays in 84 subjects without AF, who were divided into 3 groups by their CHADS₂ score. Another 17 patients who received warfarin were also assessed by DBCM to evaluate the effect of anticoagulants.

Results and Conclusions

We calculated the derivative of the dielectric permittivity change after recalcification, and extracted the end of acceleration time (EAT) as a novel index. The EAT showed a dose-dependent shortening with the addition of serial dilutions of TF (×10−² to ×10−⁴), and a dose-dependent prolongation with the addition of heparin (0.05 to 0.15 U/ml). The EAT was significantly shorter in the higher CHADS₂ score group (19.8 ± 4.8, 18.6 ± 3.1, and 16.3 ± 2.7 min in the CHADS₂ = 0, 1, and ≥2 groups, respectively, p = 0.0065 by ANOVA). Patients receiving warfarin had a significantly more prolonged EAT than those without warfarin (18.6±4.2 vs. 25.8±7.3 min, p <0.001). DBCM detected the whole blood coagulability with a high sensitivity. Subjects with higher CHADS₂ scores exhibited hypercoagulability without AF.

De-novo portal vein thrombosis in liver cirrhosis: risk factors and correlation with the Model for End-stage Liver Disease scoring system

BACKGROUND AND OBJECTIVES

Portal vein thrombosis (PVT) is a potential lethal complication in late liver cirrhosis. There is a lack of knowledge of the clinical features and risk factors of PVT. We aimed to investigate the clinical and radiological characteristics, and biochemical markers of cirrhotic patients to determine the high-risk individuals for PVT attending our center.

PATIENTS AND METHODS

Of 426 cirrhotic patients, only 120 consecutive patients were included. Clinical, biochemical, immunological, Model for End-stage Liver Disease (MELD) score, portal vein patency, and flow velocity were measured in all patients at baseline and every 6 months thereafter. Variables that could predict the development of PVT within 1 year were identified by multiple logistic regression.

RESULTS

Only 95 patients completed the study; PVT was found in 17 (17.9%) patients. PVT was observed mainly in the portal trunk, superior mesenteric vein, and splenic vein. Univariate analysis showed that diabetes mellitus, lower levels of hemoglobin, platelet counts, and portal vein flow velocity as well as increased MELD scores, platelet indices, portal vein diameter, and splenic thickness were associated with PVT patients than in non-PVT patients (all P<0.01).

CONCLUSION

The incidence of PVT was 17.9%. PVT occurred mainly in the portal vein trunk, superior mesenteric vein, and splenic vein. Diabetes mellitus, lower levels of hemoglobin, platelet count and portal vein flow velocity as well as increased MELD score, platelet indices, portal vein diameter, and splenic thickening were associated with PVT. Splenic thickening, marked reduced of mean portal flow velocity, and diabetes mellitus may be risk factors for PVT.

Evaluation of serum fibrinogen, plasminogen, α2-anti-plasmin, and plasminogen activator inhibitor levels (PAI) and their correlation with presence of retinopathy in patients with type 1 DM

BACKGROUND. Diabetic retinopathy (DR) is the leading cause of blindness in the world. Retinopathy can still progress despite optimal metabolic control. The aim of the study was to determine whether different degrees of DR (proliferative or nonproliferative) were associated with abnormally modulated hemostatic parameters in patients with T1DM. METHOD. 52 T1DM patients and 40 healthy controls were enrolled in the study. Patients were subdivided into three categories. Group I was defined as those without retinopathy, group II with NPRP, and group III with PRP. We compared these subgroups with each other and the control group (Group IV) according to the serum fibrinogen, plasminogen, alpha2-anti-plasmin ( α2-anti-plasmin), and PAI. RESULTS. We detected that PAI-1, serum fibrinogen, and plasminogen levels were similar between the diabetic and control groups (P = 0.209, P = 0.224, and P = 0.244, resp.), whereas α2-anti-plasmin was higher in Groups I, II, and III compared to the control group (P < 0.01, P < 0.05, and P < 0.001, resp.). There was a positive correlation between serum α2-anti-plasmin and HbA1c levels (r = 0,268, P = 0.031). CONCLUSION. To our knowledge there is scarce data in the literature about α2-anti-plasmin levels in type 1 diabetes. A positive correlation between α2-anti-plasmin with HbA1c suggests that fibrinolytic markers may improve with disease regulation and better glycemic control.

Cerebrovascular complications of diabetic ketoacidosis in children

Neurological deterioration in children with diabetic ketoacidosis (DKA) is commonly caused by cerebral edema. However, subtle cerebral injuries including strokes should also be suspected, since children with hyperglycemia and DKA are prone to thrombosis. In this paper, a case involving a 2 month-old patient that presented cerebral edema and stroke as complications of DKA is reported. In the discussion, the literature on neurological complications of DKA in children is briefly reviewed, emphasizing the prothrombotic tendency of these patients.

The estimation of selected endogenous anticoagulation system parameters in patients with subclinical Cushing's syndrome

OBJECTIVE

An increased tendency towards thromboembolic events is observed in patients with Cushing's syndrome. There are much fewer publications available about thromboembolic complications in patients with subclinical Cushing's syndrome (SCS). Therefore, a question arises whether hemostatic disturbances appear in this particular disease phase.

AIM OF STUDY

Estimation of protein C (PC), free protein S (FPS), antithrombin (AT) activity, thrombomodulin (TM) concentration and activated PC resistance (APCR) in patients with SCS.

MATERIALS AND METHODS

We studied 35 patients with SCS. The control group consisted of 33 healthy volunteers. The activity of PC, AT, FPS, APCR and the concentration of TM was estimated in all representatives.

RESULTS

The comparison of the examined coagulation parameters between the patients with SCS and the healthy individuals revealed significantly higher mean PC activity and mean FPS activity in the SCS group. Mean TM concentration was significantly lower in patients with SCS compared with the control group. The differences in APCR and AT activity were not significant. We did not prove any statistically significant correlations between the examined coagulation parameters and hormonal parameters. We did not find any correlation between the concentration of cortisol and basic coagulation parameters such as international normalized ratio, activated partial thromboplastin time or fibrinogen in the group with SCS either.

CONCLUSIONS

The patients with SCS present disturbances in endogenous anticoagulation system defined as PC, FPS activity and TM concentration. This finding suggests an impact of mild autonomic cortisol overproduction on coagulation system.

Diabetes mellitus is associated with shortened activated partial thromboplastin time and increased fibrinogen values

OBJECTIVE

This study was designed to examine the relationship between shortened activated partial thromboplastin time (APTT) and increased fibrinogen values with diabetes mellitus.

METHODS

APTT, prothrombin time (PT), fibrinogen, fasting plasma glucose (FPG) and glycosylated hemoglobin A1c (HbA1c) levels were measured in 1,300 patients. Patients were divided into three groups according to their HbA1c and FPG levels.

RESULTS

When participants were grouped according to their HbA1c levels, we found significantly shorter APTT values (26.9±5.6 s) and increased fibrinogen levels (3.1, 1.9-6.3 g/L) in the diabetes group when compared with the other two groups. When participants were grouped according to their FPG levels, we found significantly shorter APTT values (26.9±6.2 s) and increased fibrinogen levels (3.1, 1.8-6.2 g/L) in the diabetes group when compared with the euglycemic group.

CONCLUSIONS

Shorter APTT and increased fibrinogen levels might be useful hemostatic markers in patients with diabetes and in patients at high risk for diabetes.

The endotheliome: a new concept in vascular biology

As the importance of the endothelium is becoming increasingly recognised, additional tools are needed to assess its functions. Separate studies have looked at different aspects of vascular biology primarily focusing on the central role of the endothelium, i.e. secretion/release of molecules in the plasma, physiological action on other cells, and the presence of endothelial cells themselves in the circulation. Targeting and protecting the endothelium is a promising therapeutic strategy for modifying a number of disease processes but 'ideal' methods to monitor this treatment, like many other tools for assessing endothelial activity, remain elusive. We suggest that a broader view of the endothelium is important, and with it the concept of the assessment of overall vascular function, which fuses different aspects of endothelial activity into a unifying concept. In the present document we review the current understanding of endothelial biology and the methods of its assessment, and hypothesise that a more multifactorial approach to the endothelium will be a crucial determinant of outcomes and treatment strategies for different diseases. This we describe as the 'endotheliome'.

The influence of pre-existing diabetes mellitus on the host immune response and outcome of pneumonia: analysis of two multicentre cohort studies

BACKGROUND

Although diabetes mellitus is implicated in susceptibility to infection, the association of diabetes with the subsequent course and outcome is unclear.

METHODS

A retrospective analysis of two multicentre cohorts was carried out. The effect of pre-existing diabetes on the host immune response, acute organ function and mortality in patients hospitalised with community-acquired pneumonia (CAP) in the GenIMS study (n=1895) and on mortality following either CAP or non-infectious hospitalisations in the population-based cohort study, Health ABC (n=1639) was determined. Measurements included the mortality rate within the first year, risk of organ dysfunction, and immune responses, including circulating inflammatory (tumour necrosis factor, interleukin 6, interleukin 10), coagulation (Factor IX, thrombin-antithrombin complexes, antithrombin), fibrinolysis (plasminogen-activator inhibitor-1 and D-dimer) and cell surface markers (CD120a, CD120b, human leucocyte antigen (HLA)-DR, Toll-like receptor-2 and Toll-like receptor-4).

RESULTS

In GenIMS, diabetes increased the mortality rate within the first year after CAP (unadjusted HR 1.41, 95% CI 1.12 to 1.76, p=0.002), even after adjusting for pre-existing cardiovascular and renal disease (adjusted HR 1.3, 95% CI 1.03 to 1.65, p=0.02). In Health ABC, diabetes increased the mortality rate within the first year following CAP hospitalisation, but not after hospitalisation for non-infectious illnesses (significant interaction for diabetes and reason for hospitalisation (p=0.04); HR for diabetes on mortality over the first year after CAP 1.87, 95% CI 0.76 to 4.6, p=0.16, and after non-infectious hospitalisation 1.16, 95% CI 0.8 to 1.6, p=0.37). In GenIMS, immediate immune response was similar, as evidenced by similar circulating immune marker levels, in the emergency department and during the first week. Those with diabetes had a higher risk of acute kidney injury during hospitalisation (39.3% vs 31.7%, p=0.005) and they were more likely to die due to cardiovascular and kidney disease (34.4% vs 26.8% and 10.4% vs 4.5%, p=0.03).

CONCLUSIONS

Pre-existing diabetes was associated with a higher risk of death following CAP. The mechanism is not due to an altered immune response, at least as measured by a broad panel of circulating and cell surface markers, but may be due to worsening of pre-existing cardiovascular and kidney disease.

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSION

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

Platelet activity, reactivity and platelet-leukocyte conjugate formation before and after exhaustive or moderate exercise in patients with IDDM

Diabetes mellitus alters blood coagulation and platelet function which supports the suggestion that diabetes mellitus is a hypercoagulable state. Firstly the aim of the study was to investigate if differences in platelet activity, reactivity and platelet-leukocyte conjugate (PLC) formation can be observed in subjects with IDDM; secondly, if differences can be seen between the diabetic and control group concerning exercise-induced changes in platelet activation and conjugate formation; and thirdly, if different types of exercise lead to different patterns in platelet activation. Sixteen subjects with IDDM and 16 controls underwent a maximal step test and an endurance test (90% IAT, 45 min). Blood samples were taken after 30 min rest, and immediately and 1 h after completion of exercise. CD62P expression and differentiated platelet-leukocyte conjugates (CD45, CD14, CD41) were detected flow-cytometrically with and without stimulation with TRAP-6. The rest values of the platelet-granulocyte (PGC) and platelet-lymphocyte conjugates (PLyC) were higher (P < 0.05) in the diabetics. After exercise, platelet reactivity (CD62P-TRAP; P < 0.05) but not the activity (CD62P-unstimulated), as well as all different conjugates with or without stimulation were increased (P < 0.05) independently from the group. Differences according to the type of exercise were barely observable. IDDM without vascular complications leads to higher PCG and PLyC at rest and to identical increases in differentiated platelet-leukocyte formation after exercise in comparison with matched controls.

Study of factor VII, tissue factor pathway inhibitor and monocyte tissue factor in noninsulin-dependent diabetes mellitus

Changes in plasma tissue factor (TF)-activated factor VII (FVIIa) and plasma tissue factor pathway inhibitor (TFPI) in type II diabetes mellitus are assessed, vascular complicated and noncomplicated patients compared, and whether these novel hemostatic activity markers predict vascular complications in diabetic patients, improving risk assessment, is determined. Fifty type II diabetic patients and 20 healthy controls (age, sex and body mass matched) underwent medical history and examination, fasting plasma glucose level, glycosylated hemoglobin (HbA1c), lipid profile, hemostatic parameters, plasma TF activity, and TFPI and TF expression on blood monocytes. Mean TF, TF activity, TFPI, and FVIIa significantly increased among hyperlipidemic compared with normolipidemic diabetic patients, and normolipidemic diabetic patients compared with controls. Mean percentage TF-positive monocytes with and without lipopolysaccharide, plasma TF activity, TFPI and FVIIa were significantly higher among complicated than noncomplicated diabetic patients. Mean percentage TF-positive monocytes without and with lipopolysaccharide, plasma TF activity, plasma TFPI and FVIIa were higher among diabetic patients with macrovascular compared with microvascular complications. High significant correlation occurred between HbA1c, triglycerides and percentage TF-positive monocytes with and without lipopolysaccharide stimulation, plasma TF activity and both FVIIa and TFPI. High activity levels of plasma TF and FVIIa with increased circulating TF-positive monocytes occurred in type II diabetic patients, especially with vascular complications. Results reflect high procoagulant activity possibly involved in diabetic vascular complications. Elevated TFPI levels were observed, but were not sufficient to balance high procoagulant activity. Correlation of procoagulant activity markers with HbA1c reinforces the importance of optimal glycemic control in type II diabetes.

Circulating platelet-leukocyte aggregates: a marker of microvascular injury in diabetic patients

Diabetes is associated with multiple disorders including metabolic, cellular and blood disturbances leading to vascular complications. Increased circulating levels of platelet-leukocyte aggregates (PLA) have been described in several thrombotic diseases. In this study, we have evaluated circulating PLA in diabetic patients and we have investigated whether they may be a marker of vascular complications. Using flow cytometry assay, we have quantified PLA percentages in 65 diabetics including 20 patients with type I and 45 with type II diabetes, and 25 healthy subjects. Specific labelling identified platelet-polymorphonuclear aggregates (PPA) and platelet-monocyte aggregates (PMA). We have observed a significant increase of PPA and PMA levels in diabetics (22+/-12% and 45+/-18%, respectively) compared to controls (7+/-4% and 19+/-10%, respectively) (p<0.01). However, both PPA and PMA values were similar in the two diabetes types. Circulating PPA and PMA were significantly enhanced in diabetics with vascular lesions (PPA: 24+/-13%; PMA: 50+/-18%) than in diabetics without vascular lesions (PPA: 18+/-8%; PMA: 38+/-15%) (p<0.05 and p<0.01). Patients with PPA>18% and/or PMA>38% showed a more important vascular injury (OR: 6; 95% CI: 1.6-23). Increased PMA circulating rate is particularly correlated to retinopathic injury (OR: 19; 95% CI: 2.3-154). Our findings established a relationship between increased circulating PLA levels, particularly PMA, and the incidence of microvascular complications in diabetes. They reinforce the concept of pro-inflammatory cells involvement in diabetic retinopathy pathogenesis and their link with thrombotic process.

Extensive venous thrombosis of the upper extremity in a diabetic patient with a hyperosmolar hyperglycemic state

We report a case of extensive venous thrombosis of the upper extremity in a patient with a hyperosmolar hyperglycemic state (HHS). Thrombosis of the upper extremities is generally found in 4% of cases with deep venous thrombosis. Extensive, symptomatic venous thrombosis of the upper extremity, as seen in this patient, is rare except with catheter-related thrombosis. Recent studies have supported the safety and efficacy of catheter-directed thrombolysis in patients with no contraindication to thrombolytic therapy, and have recommended early catheter-directed thrombolysis. Therefore, our patient was treated with early catheter-directed thrombolysis followed by anticoagulation.

Pediatric stroke associated with new onset type 1 diabetes mellitus: case reports and review of the literature

Neurological deterioration in children with diabetic ketoacidosis (DKA) is commonly caused by cerebral edema. However, stroke should also be suspected when focal neurological deficits are apparent, because children with hyperglycemia and DKA are prone to thrombosis. We report three cases of pediatric stroke associated with new onset type 1 diabetes mellitus (T1DM). The first case presented with sinovenous thrombosis, and the other two cases presented in DKA and had a late diagnosis of ischemic stroke following neurological deterioration. Our recent experiences and review of the literature emphasize the importance of early diagnosis, investigation, and treatment for patients that present with new onset T1DM and stroke.

Soluble tissue factor is a candidate marker for progression of microvascular disease in patients with Type 2 diabetes

OBJECTIVE

To determine the relationship between abnormalities in blood coagulation and prevalent or incident cardiovascular complications in Type 2 diabetes.

DESIGN AND METHODS

Prospective cohort study of 128 patients with Type 2 diabetes in whom blood samples were collected at baseline and after 1 year of follow-up. All cardiovascular complications at baseline and follow-up were recorded. Forty-three healthy, age-matched subjects served as a control group.

RESULTS

Logistic analysis revealed an independent relationship between soluble tissue factor (TF) and microvascular disease [per pg mL(-1) TF: Exp(B) = 1.008; CI(95%)1.002-1.014], or neurogenic disease [Exp(B) = 1.006; CI(95%)1.001-1.011]. The highest levels of soluble TF were observed in patients with microvascular and neurogenic disease (P < 0.001). Patients with Type 2 diabetes having a soluble TF concentration >300 pg mL(-1) are at a 15-fold higher risk for the presence of microvascular disease and at a 10-fold higher risk for the presence of neurogenic disease compared with the patients with concentrations below 100 pg mL(-1). Soluble TF was correlated with tissue type plasminogen activator, von Willebrand factor antigen, systolic blood pressure and age. Levels of F1' + 2, D-dimer, FVIII activity, t-PA and vWFag were not different among patients with micro-, macro- or neurogenic complications compared with patients without those complications. Forty-eight new micro-, macro- and/or neurogenic complications were diagnosed after 1 year follow-up. With the exception of higher F1 + 2 levels after 1 year all other markers remained unchanged. A trend toward higher soluble TF levels was observed in patients with new microvascular events (P = 0.056).

CONCLUSIONS

Soluble TF is associated with existing microvascular and neurogenic complications in patients with Type 2 diabetes and is a candidate marker for progression of microvascular disease.

Thrombin-activatable fibrinolysis inhibitor activity and global fibrinolytic capacity in Type 1 diabetes: evidence for normal fibrinolytic state

Hypofibrinolysis is a state that is commonly observed in type 2 diabetic patients, a finding also possibly related to obesity and insulin resistance. There is little information, however, regarding the status of fibrinolytic system in Type 1 diabetes, in particular as reflected by thrombin-activatable fibrinolysis inhibitor (TAFI) activity and global fibrinolytic capacity (GFC). To provide information in this respect, 30 Type 1 diabetic patients (median age=16) and 28 healthy controls (median age=14) were enrolled in this study. The median duration of diabetes was 7 years, and median HbA(1c) was 8.85% (range: 5.5-11.9%) in the diabetic group. None of the patients had macrovascular complications. Microvascular complications were present in a total of eight patients (nephropathy: n=5; retinopathy: n=3). A comparison of the TAFI activity between the patient (median 84.9, range: 71.5-103.3%) and the control groups (median=83.3, range: 63.7-97.4%) yielded no statistically significant difference (P=.950). Similarly, GFC was comparable between the two groups (median=8.22, range: 0.72-22.38 microg/ml, and median=13.32, range: 3.0-23.22 microg/ml, respectively, in the diabetic and control groups, P=.086). TAFI activity did not significantly correlate with age, albumin excretion, fasting plasma glucose, HbA(1c), D-dimer, and fibrinogen by Spearman rank correlation test. There was as a significant inverse correlation between GFC and TAFI activity (r=-.414, P=.006). Contrary to the previous observations in Type 2 diabetes, our data suggest that fibrinolytic activity is not adversely affected by Type 1 diabetes, and it has no relationship with the degree of metabolic control.

Type 2 diabetes mellitus: a cardiovascular perspective

Diabetes mellitus is a disease, which is at the epitome of cardiovascular risk factors causing considerable morbidity and mortality. In addition to microvascular complications, there is two- to six-fold increased risk of macrovascular diseases, such as coronary artery disease, peripheral artery disease and stroke. While the mortality from coronary artery disease in patients without diabetes has declined over the past 20 years, the mortality in men with type 2 diabetes mellitus has not changed. Furthermore, the prevalence of diabetes in the UK has increased by 30% since 1991 and the same among the world population in 2010 is expected to be twice in 1990. This dramatic increase has serious implications from a cardiovascular perspective and thus the aggressive management of blood pressure, dyslipidaemia and blood glucose in diabetes is of vital importance. The aim of this review is to evaluate the current evidence and to discuss the implications of type 2 diabetes and its relevance to clinical practice in cardiology. We address this broad subject in discussing (i) the pathophysiology of cardiovascular disease in the setting of type 2 diabetes and (ii) the prevalence of cardiovascular risk, complications and prognostic implications in type 2 diabetes, with a discussion of current therapeutic interventions for the prevention or delay of these consequences where relevant.

A hypothesis-generating study to evaluate platelet activity in diabetics with chronic kidney disease

Background

It is well described that diabetes mellitus is a hypercoagulable state. It is also known that patients with renal dysfunction have impaired platelet aggregation and function. It is not well described how renal dysfunction affects the hypercoagulability associated with diabetes. This post-hoc sub-group analysis compares platelet function, clot structure and thrombin generation time at baseline, and following enoxaparin exposure in three groups of subjects.

Methods

30 total subjects were evaluated in the three groups: Group I: normal controls (n = 10), Group II: subjects with renal dysfunction but without diabetes (n = 13), and Group III: subjects with concomitant diabetes and renal dysfunction (n = 7). For each subject, platelet contractile force (PCF), clot elastic modulus (CEM) and thrombin generation time (TGT) were simultaneously measured in whole blood at baseline, and following increasing enoxaparin antifactor Xa activity exposure. The group means for each parameter were determined and compared using one-way analysis of variance, with post-hoc Tukey-Kramer test.

Results

At baseline, subjects in Group III (diabetics with concomitant renal dysfunction) display significantly enhanced platelet activity, as measured by PCF (p = 0.003) and CEM (p = 0.03), relative to the non-diabetic Groups I and II. Subjects in Group II (renal dysfunction without diabetes) had significantly prolonged TGT values relative to controls when the antifactor Xa activity concentration reached 0.5 (p = 0.007), 1.0 (p = 0.005) and 3.0 IU/mL (p < 0.0001), respectively. There were no differences between Group II and Group III with respect to TGT at these antifactor Xa activity concentrations. When the antifactor Xa activity concentration reached 3.0 IU/mL, Groups II and III formed significantly less rigid blood clots (CEM p = 0.003) and also trended toward reduced PCF (p = 0.06) relative to Group I.

Conclusion

This hypothesis-generating sub-group analysis suggests that at baseline, patients with concomitant diabetes and renal dysfunction have significantly enhanced platelet activity (PCF), and form more rigid blood clots (CEM) compared to controls and subjects with renal dysfunction but no diabetes. This may suggest that the presence of renal dysfunction does not ameliorate the hypercoagulable state associated with diabetes. Secondly, it appears that subjects with renal dysfunction but without diabetes have an enhanced response to enoxaparin relative to controls.

Urinary albumin excretion is correlated to fibrinogen levels and protein S activity in patients with type 1 diabetes mellitus without overt diabetic nephropathy

The aim of the study was to test the hypothesis that in diabetic patients without overt nephropathy there may be a correlation between the activity of natural anticoagulant proteins and glomerular dysfunction. Assays for functional activity of proteins S and C, measurements of urinary albumin excretion, lipid parameters and haemoglobin A1c were performed in 91 patients with type 1 diabetes mellitus and 85 patients with type 2. Patients with type 1 diabetes and microalbuminuria had significantly higher mean age (44.1 +/- 10.9 vs. 37.9 +/- 12.7 years; p<0.05), fibrinogen level (3.75 +/- 1.0 vs. 3.21 +/- 0.8 g/l; p<0.01), protein S activity (92.3 +/- 17.6 vs. 84.5 +/- 15.5%; p<0.05) and higher prevalence of retinopathy (p<0.01) and macrovascular disease (p<0.01) than those with normoalbuminuria. Albumin excretion was significantly correlated to age (r=0.25, p<0.05), fibrinogen level (r=0.39, p<0.01), protein S activity (r=0.27; p<0.05), total cholesterol (r=0.23; p<0.05), apoprotein B (r=0.22; p<0.05), retinopathy (r=0.33; p<0.01) and macrovascular disease (r=0.33; p<0.01). Patients with type 2 diabetes mellitus and microalbuminuria had significantly higher apoprotein B levels (1.17 +/- 0.3 vs. 1.06 +/- 1.2 mg/dl; p<0.05) than those with normoalbuminuria, and apoprotein B was significantly correlated to albumin excretion (r=0.22; p<0.05). In a multivariate model of type 1 diabetes mellitus with fibrinogen, protein S and C activity, cholesterol, triglycerides, haemoglobin A1c, retinopathy, and macrovascular disease as independent parameters (r=0.53; p<0.003), there was significant independent correlation of fibrinogen (beta=0.28; p<0.01), protein S activity (beta=0.27; p<0.05) and retinopathy (beta=0.21; p<0.01) with albumin excretion. We conclude that in type 1 diabetes, relative elevation of fibrinogen level and protein S activity appear in the early stages of development of diabetic nephropathy, and may be related to the pathogenesis of diabetic kidney disease.

Thrombin activatable fibrinolysis inhibitor and hemostatic changes in patients with type I diabetes mellitus with and without microvascular complications

We investigated thrombin activatable fibrinolysis inhibitor (TAFI) and its influence on fibrinolysis by measuring pro-TAFI activity and total TAFI antigen in 38 patients with type I diabetes mellitus (18 with and 20 without microvascular complications), as well as in 20 healthy controls. The pro-TAFI levels in the two groups of patients did not differ from those in the control group. Total TAFI antigen [i.e. pro-TAFI, TAFI and inactive carboxypeptidase U (TAFIi)] tended to decrease in both the patient groups (59.7 +/- 7.2 and 73.4 +/- 8.9% with and without microvascular complications, respectively) compared with controls (91.9 +/- 12.2%) (P = 0.12). We also assessed the overall hemostatic potential (OHP) in plasma, the clot lysis time and the overall fibrinolytic potential. The OHP was significantly higher in patients with complications compared with controls (8.9 +/- 0.9 versus 6.7 +/- 0.4; P < 0.05) and also higher in the diabetics without complications (7.8 +/- 0.6), although the latter difference did not reach statistical significance. Levels of clot lysis time and overall fibrinolytic potential were similar in the two groups of patients and the controls. The increased OHP in plasma from diabetic patients with microvascular complications indicates an imbalance of the hemostatic system towards a prothrombotic state. No signs of impaired fibrinolysis were observed in patients with diabetes. Using the OHP method for estimation of overall hemostasis, it seems that TAFI does not influence either fibrinolysis or the increased thrombotic potential observed in patients with type I diabetes mellitus.

Increased plasma thrombin-activatable fibrinolysis inhibitor levels in normotensive type 2 diabetic patients with microalbuminuria

Hypofibrinolysis is a common finding in patients with diabetes mellitus and a risk factor for diabetic nephropathy. Recently, a new potent inhibitor of fibrinolysis, the thrombin-activatable fibrinolysis inhibitor (TAFI), has been isolated from human plasma. The possibility that TAFI also participates in the mechanism of hypofibrinolysis has not been appraised in diabetic patients with microalbuminuria. In the present study, we investigated the plasma levels of TAFI and its relation to urinary albumin excretion in normotensive diabetic patients with normo- and microalbuminuria. Thirty-nine normotensive nonobese type 2 diabetic patients (27 with normoalbuminuria, 12 with microalbuminuria) and 20 age-matched normal subjects were enrolled in this study. The plasma level of thrombin-antithrombin complex was significantly increased (22.1 +/- 2.6 vs. 8.3 +/- 1.0 nmol/liter; P < 0.05), whereas the D-dimer/thrombin-antithrombin complex ratio was significantly decreased (15.7 +/- 1.4 vs. 26.5 +/- 2.2; P < 0.05), showing the occurrence of hypercoagulability and hypofibrinolysis in diabetic patients. The plasma level of TAFI in diabetic patients was significantly elevated, compared with normal subjects (147.4 +/- 11.6 vs. 99.5 +/- 4.9%; P < 0.05). The plasma level of TAFI in diabetic patients with microalbuminuria was significantly higher than the level in diabetic patients with normoalbuminuria (194.1 +/- 24.5 vs. 128.8 +/- 12.3%; P < 0.02) or normal subjects (194.1 +/- 24.5 vs. 99.5 +/- 4.9%; P < 0.005). Univariate analysis showed that the plasma TAFI levels are significantly and proportionally correlated with urinary albumin excretion rate (r = 0.58; P < 0.005) and with plasma soluble thrombomodulin level, a marker of endothelial cell damage, in all diabetic patients (r = 0.42; P < 0.01). These data suggest that increased plasma level of TAFI may be involved in the mechanism of vascular endothelial damage in patients with type 2 diabetes mellitus.

Platelet contractile force (PCF) and clot elastic modulus (CEM) are elevated in diabetic patients with chest pain

AIMS

Platelet function and clot structure may be altered in diabetes. We have noted increased platelet contractile force (PCF) and clot elastic modulus (CEM) in patients presenting to the emergency department with chest pain. Twenty-six of the chest pain patients were diabetic. Here, we compare the PCF, CEM and platelet aggregation in diabetic chest pain patients, non-diabetic patients with chest pain and asymptomatic controls.

PATIENTS AND METHODS

PCF, CEM and collagen whole blood aggregations were measured in 100 chest pain patients and 25 asymptomatic controls.

RESULTS

Platelet concentrations for diabetic patients, non-diabetic patients and controls were identical. PCF was significantly (P < 0.05) elevated in diabetic chest pain patients (9.42 +/- 0.59 kdynes) vs. controls (7.40 +/- 0.32 kdynes). CEM in diabetic patients (29.96 +/- 2.19 kdynes/cm2) was significantly elevated relative to that in non-diabetic chest pain patients (25.22 +/- 0.84 kdynes/cm2) and normal controls (23.18 +/- 0.74 kdynes/cm2). Collagen-induced whole blood aggregation was decreased (P < 0.05) in diabetic chest pain patients vs. controls. PCF values (10.23 +/- 0.76 kdynes) in diabetic patients with haemoglobin A1c > 7% were higher than in any other group.

CONCLUSION

PCF and CEM are elevated in diabetic chest pain patients. The significance of these laboratory findings awaits additional clinical studies.

Type 1 and type 2 diabetic patients display different patterns of cellular microparticles

The development of vasculopathies in diabetes involves multifactorial processes including pathological activation of vascular cells. Release of microparticles by activated cells has been reported in diseases associated with thrombotic risk, but few data are available in diabetes. The aim of the present work was to explore the number and the procoagulant activity of cell-derived microparticles in type 1 and 2 diabetic patients. Compared with age-matched control subjects, type 1 diabetic patients presented significantly higher numbers of platelet and endothelial microparticles (PMP and EMP), total annexin V-positive blood cell microparticles (TMP), and increased levels of TMP-associated procoagulant activity. In type 2 diabetic patients, only TMP levels were significantly higher without concomitant increase of their procoagulant activity. Interestingly, in type 1 diabetic patients, TMP procoagulant activity was correlated with HbA(1c), suggesting that procoagulant activity is associated with glucose imbalance. These results showed that a wide vesiculation process, resulting from activation or apoptosis of several cell types, occurs in diabetes. However, diabetic patients differ by the procoagulant activity and the cellular origin of microparticles. In type 1 diabetic patients, TMP-procoagulant activity could be involved in vascular complications. Moreover, its correlation with HbA(1c) reinforces the importance of an optimal glycemic control in type 1 diabetes.

Vascular involvement in Behçet's disease: relation with thrombophilic factors, coagulation activation, and thrombomodulin

PURPOSE

Thrombosis, usually venous, occurs in 10% to 25% of patients with Behçet's disease, but its pathogenesis is poorly understood. We evaluated parameters of hemostasis and their relation with thrombosis in a series of patients with Behçet's disease.

SUBJECTS AND METHODS

We studied 38 patients with Behçet's disease (13 with venous thrombosis), 38 patients with venous thrombosis without thrombophilia, and 100 control subjects. Levels or presence of protein C, protein S, antithrombin, methylenetetrahydrofolate reductase C677T, factor V Leiden, prothrombin gene G20210A, antiphospholipid antibodies, plasminogen, tissue-type plasminogen activator (tPA), type-1 tPA inhibitor (PAI-1), PAI-1 4G/5G polymorphism, prothrombin fragment 1+2, plasmin/alpha(2)-antiplasmin complexes, thrombomodulin, and activated factors VII and XII were determined.

RESULTS

There were no deficiencies in protein C, protein S, antithrombin, or factor V Leiden in the patients with Behçet's disease, nor was there evidence of most other thrombotic abnormalities. Compared with control subjects, however, the Behçet's disease group had elevated mean (+/- SD) levels of prothrombin fragment 1+2 (2091 +/- 1323 pmol/L vs. 804 +/- 398 pmol/L, P <0.001), plasmin/alpha2-antiplasmin complexes (410 +/- 220 microg/L vs. 214 +/- 92 microg/L, P <0.001), and thrombomodulin (37 +/- 24 ng/mL vs. 27 +/- 10 ng/mL, P <0.001). These levels did not differ between patients with or without thrombosis.

CONCLUSIONS

Thrombophilic factors do not seem to explain most thromboses in Behçet's disease. There is increased thrombin generation, fibrinolysis, and thrombomodulin in Behçet's disease, but these abnormalities are not related to thrombosis.

Separation and characterization of the molecular species of thrombomodulin in the plasma of diabetic patients

Thrombomodulin (TM) and its molecular species have been identified as markers of vascular endothelial cells (EC). In the present study, using high-performance liquid chromatography (HPLC) in 7 normal subjects, 5 chronic glomerulonephritis (GN) patients, and 25 diabetes mellitus (DM) patients, the TM molecular species separated from plasma showed seven heterogeneous fragments of 94, 74, 48, 36, 27, 14, and 12 kDa. Comparing the diabetic patients and healthy subjects, it was found that plasma TM generally, and its 74-kDa molecular species particularly, were increased in diabetic patients and the increase became more apparent as the disease progressed in severity. Comparing the patients with diabetic nephropathy and those with nephritis of the same degree of renal dysfunction, both groups had increased levels of TM, but the distribution of the molecular species differed; that is, the 74-kDa form increased in the diabetic patients and the 12-kDa species increased markedly in the nephritis patients. Glycation of the various TM molecular species increased more in the diabetic patients than in healthy subjects. There was a significantly positive correlation between the HbA(1c) and the 74-kDa TM molecular species in diabetic patients. These findings suggest that a fluctuation in the blood glucose level is significantly related to vascular EC damage in DM.

Factor VII, tissue factor pathway inhibitor, and monocyte tissue factor in diabetes mellitus: influence of type of diabetes, obesity index, and age

Changes of the tissue factor (TF) pathway of blood coagulation have been described in diabetes and could be involved in its vascular complications. In order to evaluate the influence of the type of diabetes and of the obesity index and age on these changes, factor VII coagulant activity, factor VII antigen, activated factor VII, monocyte TF expression, and plasma Tissue Factor Pathway Inhibitor (TFPI) were examined in 18 Type 1 and 16 Type 2 diabetic patients compared to non-diabetic control subjects matched for age, sex, and obesity index (Types 1 and 2 controls, respectively). Multicomplicated patients were excluded. FVIIc, FVIIAg, and FVIIa were higher in Type 2 diabetic patients and controls than in Type 1 diabetic patients and controls (P< .03). However, FVIIc and FVIIAg were lower in diabetic patients than in their matched controls (P< .03). Monocyte expression of TF was not different between Types 1 and 2 diabetic patients and their matched controls except for LPS-stimulated monocyte TF activity which was lower in Type 2 diabetic patients than in Type 2 controls (P< .05). Plasma TFPI was slightly but significantly higher in Type 1 diabetic patients than in Type 1 controls (P= .01) and was correlated to glycemia. However, both in Type 2 diabetic patients and controls, TFPI was higher than in Type 1 controls and was correlated with BMI (P< .0003). These results indicate that in not multicomplicated patients, the increase of FVII and TFPI was highly dependent on obesity index and age rather than on diabetes by itself.

Diabetes mellitus: a hypercoagulable state

Eighty percent of patients with diabetes mellitus die a thrombotic death. Seventy-five percent of these deaths is due to cardiovascular complications, and the remainder is due to cerebrovascular events and peripheral vascular complications. Vascular endothelium, the primary defense against thrombosis, is abnormal in diabetes. Endothelial abnormalities undoubtedly play a role in the enhanced activation of platelets and clotting factors seen in diabetes. Coagulation activation markers, such as prothrombin activation fragment 1+2 and thrombin-anti-thrombin complexes, are elevated in diabetes. The plasma levels of many clotting factors including fibrinogen, factor VII, factor VIII, factor XI, factor XII, kallikrein, and von Willebrand factor are elevated in diabetes. Conversely, the level of the anticoagulant protein C (PC) is decreased. The fibrinolytic system, the primary means of removing clots, is relatively inhibited in diabetes due to abnormal clot structures that are more resistant to degradation and an increase in plasminogen activator inhibitor type 1 (PAI-1). Increased circulating platelet aggregates, increased platelet aggregation in response to platelet agonists, increased platelet contractile force (PCF), and the presence of higher plasma levels of platelet release products, such as beta-thromboglobulin, platelet factor 4, and thromboxane B(2), demonstrate platelet hyperactivity in diabetes. This constellation of findings supports the clinical observation that diabetes is a hypercoagulable state. This article briefly reviews the published evidence for this conclusion and the putative roles played by hyperglycemia and hyperinsulinemia in its development.

The 4G/5G polymorphism of the type 1 plasminogen activator inhibitor gene and thrombosis in patients with antiphospholipid syndrome

OBJECTIVE

To investigate the relationship between the 4G/5G polymorphism of the type 1 plasminogen activator inhibitor (PAI-1) gene and thrombotic manifestations in patients with antiphospholipid syndrome (APS).

METHODS

We studied a total of 247 patients included in the following 4 groups: 70 patients with primary APS, 104 patients with systemic lupus erythematosus (40 with antiphospholipid antibodies [aPL] and clinical [secondary] APS, 13 with aPL but without clinical APS, and 51 with neither detectable aPL nor a history of thrombosis), 14 asymptomatic individuals with aPL, and 59 patients with thrombosis but without known thrombosis risk factors. A control group of 100 healthy individuals was also analyzed. PAI-1 4G/5G polymorphism was determined by polymerase chain reaction and endonuclease digestion.

RESULTS

The allele frequency of 4G/5G in controls was 0.47/0.53. There were no differences in allele distribution among patient groups or between patients and controls. However, a higher frequency of the 4G allele was observed in APS patients with versus those without thrombosis (0.57 versus 0.39; P < 0.05) (odds ratio [OR] 2.83, 95% confidence interval [95% CI] 1.18-6.76). This higher frequency of the 4G allele was attributable to the higher frequency in patients with versus those without arterial thrombosis (0.64 versus 0.43; P < 0.01) (OR 5.96, 95% CI 1.67-21.32), while patients with venous thrombosis had an allele distribution similar to that of those without venous thrombosis (0.49 versus 0.50; P not significant). There was a trend toward higher PAI-1 antigen and activity levels in APS patients and controls with the 4G/4G genotype, but this did not reach statistical significance.

CONCLUSION

The presence of the 4G allele of the 4G/5G polymorphism of the PAI-1 gene may be an additional risk factor for the development of arterial thrombosis in APS.

Reverse cholesterol transport in diabetes mellitus

There are epidemiological data and experimental animal models relating the development of premature atherosclerosis with defects of the reverse cholesterol transport (RCT) system. In this regard, the plasma concentrations of the high density lipoprotein (HDL) subfractions, of cholesteryl ester transfer protein (CETP), as well as the activity of the enzyme lecithin-cholesterol acyl transferase (LCAT) play critical roles. However, there has been plenty of evidence that atherosclerosis in diabetes mellitus (DM) is ascribed to a greater arterial wall cell uptake of modified apoB-containing lipoproteins whereas a primary or predominant defect of the RCT system is still a subject of debate. In other words, in spite of the fact that in DM the composition and rates of metabolism of the HDL particles are greatly altered and display a diminished in vitro efficiency to remove cell cholesterol, definitive in vivo demonstration of the importance of this fact in atherogenesis is lacking. Furthermore, the roles played by LCAT and CETP in RCT in DM are difficult to interpret because the in vitro procedures of measurement utilized have either been inadequate, or inappropriately interpreted. Knock-out or transgenic mice are much needed models to investigate the roles of LCAT, CETP, phospholipid transfer protein (PLTP), and of a CETP inhibitor in the development of atherosclerosis of experimental DM.

Predictors of stent thrombosis after primary stenting for acute myocardial infarction

The aim of the study was to determine if a hypercoagulable state that may persist for several months after an acute myocardial infarction may contribute to an increased incidence of stent thrombosis. Primary stenting was performed in 104 consecutive patients with acute myocardial infarction using 147 coronary stents. Twenty-eight patients (27%) were diabetic and 55 patients (53%) were smokers. A single stent was placed in 63%, two stents in 33%, and more than two stents in 4% of the patients. Procedural success was obtained in 97% of the patients. All stents were deployed using high-pressure balloon inflation. The reference vessel diameter and minimal lumen diameter after stent deployment were 3.30 +/- 0.42 and 3.23 +/- 0.42 mm, respectively. Six patients (5.7%) developed stent thrombosis within 1 month after the procedure complicated by reinfarction in five of the six patients. At 1-month follow-up, all patients remained alive. On multivariate analysis, independent predictors of stent thrombosis were diabetes mellitus (relative risk [RR] 5.2; 95% confidence interval [CI] 1.8, 25.1), tobacco use (RR 4.5; 95% CI 1.3, 24.5), number of stents: 1 vs. > 1 (RR 3.7; 95% CI 1.1, 15.9), minimal lumen diameter poststent placement (RR 0.03; 95% CI 0.0002, 0.74), and duration of chest pain before intervention (RR 1.1; 95% CI 1.01, 1.25). Stent thrombosis had not been associated with diabetes mellitus and tobacco use previously but is in agreement with the enhanced platelet aggregability, coagulation factor abnormalities, and impaired fibrinolysis characteristic of these patients.

Thrombomodulin: an overview and potential implications in vascular disorders

Thrombomodulin (TM), a high affinity thrombin receptor present on endothelial cell membrane, plays an important role as a natural anticoagulant. It acts as a cofactor of thrombin-catalyzed activation of protein C, and inhibits the procoagulant functions of thrombin. TM is also located in other cells (keratinocytes, osteoblasts, macrophages,...) where it might be involved in cell differentiation or in inflammation. In the presence of cytokines, activated neutrophils and macrophages, endothelial TM is cleaved enzymatically, releasing soluble fragments which circulate in the blood and are eliminated in urine. Plasma TM level (pTM) can be measured using a two-site enzyme-linked immunosorbent assay (ELISA). pTM level is regarded as a molecular marker reflecting injury of endothelial cells. It is often increased in case of diffuse endothelial damage as in disseminated intravascular coagulation, diabetic microangiopathy, Plasmodium falciparum and rickettsial infections. pTM is also a predictive marker of hypertensive complications in pregnancy. In several systemic inflammatory diseases, pTM levels are correlated to the activity of the disease.