Impaired glucose metabolism and type 2 diabetes are associated with hypercoagulability: potential role of central adiposity and low-grade inflammation--the Hoorn Study

The thrombin receptor PAR4 supports visceral adipose tissue inflammation

Thrombin inhibition suppresses adiposity, WAT inflammation and metabolic dysfunction in mice. Protease-activated receptor (PAR)1 does not account for thrombin-driven obesity, so we explored the culprit role of PAR4 in this context. Male WT and PAR-4-/- mice received a high fat diet (HFD) for 8 weeks, WT controls received standard chow. Body fat was quantified by NMR. Epididymal WAT was assessed by histology, immunohistochemistry, qPCR and lipase activity assay. 3T3-L1 preadipocytes were differentiated ± thrombin, acutely stimulated ± PAR4 activating peptide (AP) and assessed by immunoblot, qPCR and U937 monocyte adhesion. Epicardial adipose tissue (EAT) from obese and lean patients was assessed by immunoblot. PAR4 was upregulated in mouse WAT under HFD. PAR4-/- mice developed less visceral adiposity and glucose intolerance under HFD, featuring smaller adipocytes, fewer macrophages and lower expression of adipogenic (leptin, PPARγ) and pro-inflammatory genes (CCL2, IL-1β) in WAT. HFD-modified activity and expression of lipases or perilipin were unaffected by PAR4 deletion. 3T3-L1 adipocytes differentiated with thrombin retained Ki67 expression, further upregulated IL-1β and CCL2 and were more adhesive for monocytes. In mature adipocytes, PAR4-AP increased phosphorylated ERK1/2 and AKT, upregulated Ki67, CCl2, IL-β and hyaluronan synthase 1 but not TNF-α mRNA, and augmented hyaluronidase-sensitive monocyte adhesion. Obese human EAT expressed more PAR4, CD68 and CD54 than lean EAT. PAR4 upregulated in obesity supports adipocyte hypertrophy, WAT expansion and thrombo-inflammation. The emerging PAR4 antagonists provide a therapeutic perspective in this context beyond their canonical antiplatelet action.

A Case Report of Urinary Tract Infection and Fungemia Due to Pichia ohmeri Complicated with Pulmonary Thromboembolism

Pichia ohmeri (P. ohmeri) is a rare human pathogen known to cause severe conditions such as sepsis, fungemia, endocarditis, and peritonitis, often resulting in high mortality rates. This report presents a case of a febrile 66-year-old male with a urinary tract infection and fungemia caused by P. ohmeri. The patient had additional complications of pulmonary thromboembolism (PTE) and deep venous thrombosis (DVT) in the left lower extremity. Notably, the pathogen was isolated in both urine and blood cultures, an uncommon finding in immunocompetent patients. Treatment with fluconazole was initiated based on the antifungal susceptibility testing (AFST) results. Following treatment, the patient experienced a gradual resolution of fever and urinary tract infection symptoms. Concurrently, anticoagulant therapy was administered for the management of PTE and DVT. The patient was eventually discharged in a stable condition.

Diabetes- versus smoking-related thrombo-inflammation in peripheral artery disease

Peripheral artery disease (PAD) is a major health problem with increased cardiovascular mortality, morbidity and disabling critical limb threatening ischemia (CLTI) and amputation. Diabetes mellitus (DM) and cigarette smoke are the main risk factors for the development of PAD. Although diabetes related PAD shows an accelerated course with worse outcome regarding complications, mortality and amputations compared with non-diabetic patients, current medical treatment does not make this distinction and includes standard antiplatelet and lipid lowering drugs for all patients with PAD. In this review we discuss the pathophysiologic mechanisms of PAD, with focus on differences in thrombo-inflammatory processes between diabetes-related and smoking-related PAD, and hypothesize on possible mechanisms for the progressive course of PAD in DM. Furthermore, we comment on current medical treatment and speculate on alternative medical drug options for patients with PAD and DM.

Diabetes mellitus and its impact on mortality rate and outcome in pulmonary embolism

AIMS/INTRODUCTION

In patients with pulmonary embolism (PE), the impact of diabetes mellitus on patient profile and outcome is not well investigated.

MATERIAL AND METHODS

The German nationwide inpatient sample of the years 2005-2018 was analyzed. Hospitalized PE patients were stratified for diabetes, and the impact of diabetes on in-hospital events was investigated.

RESULTS

Overall, 1,174,196 PE patients (53.8% aged ≥70 years, 53.5% women) and, among these, 219,550 (18.7%) diabetes patients were included. In-hospital mortality rate amounted to 15.8%, and was higher in diabetes patients than in non-diabetes patients (19.8% vs 14.8%, P < 0.001). PE patients with diabetes had a higher prevalence of cardiovascular risk factors, comorbidities, right ventricular dysfunction (31.8% vs 27.7%, P < 0.001), prolonged in-hospital stay (11.0 vs 9.0 days, P < 0.001) and higher rates of adverse in-hospital events. Remarkably, diabetes was independently associated with increased in-hospital mortality (odds ratio [OR] 1.21, 95% confidence interval [CI] 1.20-1.23, P < 0.001) when adjusted for age, sex and comorbidities. Within the observation period of 2005-2018, a relevant decrease of in-hospital mortality in PE patients with diabetes was observed (25.5% to 16.8%). Systemic thrombolysis was more often administered to diabetes patients (OR 1.18, 95% CI 1.01-3.49, P < 0.001), and diabetes was associated with intracerebral (OR 1.19, 95% CI 1.12-1.26, P < 0.001), as well as gastrointestinal bleeding (OR 1.11, 95% CI 1.07-1.15, P < 0.001). Type 1 diabetes mellitus was shown to be a strong risk factor in PE patients for shock, right ventricular dysfunction, cardiopulmonary resuscitation and in-hospital death (OR 1.75, 95% CI 1.61-1.90, P < 0.001).

CONCLUSIONS

Despite the progress in diabetes treatments, diabetes is still associated with an unfavorable clinical patient profile and higher risk for adverse events, including substantially increased in-hospital mortality in acute PE.

Global coagulation assays in hypercoagulable states

Thrombosis is one of the major global causes of morbidity and mortality, and predicting the risk of thrombotic and cardiovascular complications remains one of the key challenges in modern medicine. Conventional coagulation testing does not provide sufficient information, primarily because they measure the time to start of blood clotting and do not evaluate total thrombin generation. Possible adjunctive tools that may be helpful are global coagulation assays, which includes the assessment of the final products of the coagulation cascade, namely thrombin and fibrin. Whilst these assays have been more widely investigated in bleeding states, their role in thrombotic disorders is less established. We have previously investigated the use of assays such as thromboelastography, calibrated automated thrombogram and overall haemostatic potential assay in several hypercoagulable states including cardiovascular disease, haematological disorders and influence of hormone status as well as healthy controls. We provide a review of the use and limitations of global coagulation assays in healthy controls as well as hypercoagulable conditions.

Global coagulation assays in patients with diabetes mellitus

BACKGROUND

There is significant heterogeneity in the incidence and severity of diabetes-associated vascular complications and there is no routine biomarker that accurately predicts these outcomes. This pilot study investigates the role of global coagulation assays in patients with diabetes mellitus.

METHODS

In this cross-sectional study, patients with diabetes not on anticoagulation or dialysis and without active malignancy were recruited from endocrinology clinics. Blood samples were collected for global coagulation assays including thromboelastography (TEG), thrombin generation using calibrated automated thrombogram (CAT), and fibrin generation and fibrinolysis using the overall hemostatic potential (OHP) assay. The results were compared with healthy controls.

RESULTS

A total of 147 adult patients including 19 with type 1 diabetes (T1DM), 120 with type 2 diabetes (T2DM), and eight with latent autoimmune diabetes were recruited. Compared with 153 healthy controls, patients with diabetes demonstrated higher maximum amplitude (68.6 vs 60.2 mm, p < 0.001) on TEG, and higher OHP (9.3 vs 6.4, p < 0.001) with comparable CAT parameters. Patients with T2DM were more hypercoagulable than those with T1DM on most biomarkers. Higher maximum amplitude, velocity index, and OHP were associated with increased risk of complications (C-stat 0.82). Patients with history of microvascular complications appear to have more hypercoagulable thrombin and fibrin generation than those without.

CONCLUSION

Patients with diabetes have more hypercoagulable profiles on global coagulation assays, particularly patients with T2DM and those with microvascular complications. Further studies with longitudinal follow-up are ongoing to evaluate the utility of global coagulation assays in predicting long-term patient outcomes.

Hypofibrinolysis in type 2 diabetes and its clinical implications: from mechanisms to pharmacological modulation

A prothrombotic state is a typical feature of type 2 diabetes mellitus (T2DM). Apart from increased platelet reactivity, endothelial dysfunction, hyperfibrinogenemia, and hypofibrinolysis are observed in T2DM. A variety of poorly elucidated mechanisms behind impaired fibrinolysis in this disease have been reported, indicating complex associations between platelet activation, fibrin formation and clot structure, and fibrinolysis inhibitors, in particular, elevated plasminogen antigen inhibitor-1 levels which are closely associated with obesity. Abnormal fibrin clot structure is of paramount importance for relative resistance to plasmin-mediated lysis in T2DM. Enhanced thrombin generation, a proinflammatory state, increased release of neutrophil extracellular traps, elevated complement C3, along with posttranslational modifications of fibrinogen and plasminogen have been regarded to contribute to altered clot structure and impaired fibrinolysis in T2DM. Antidiabetic agents such as metformin and insulin, as well as antithrombotic agents, including anticoagulants, have been reported to improve fibrin properties and accelerate fibrinolysis in T2DM. Notably, recent evidence shows that hypofibrinolysis, assessed in plasma-based assays, has a predictive value in terms of cardiovascular events and cardiovascular mortality in T2DM patients. This review presents the current data on the mechanisms underlying arterial and venous thrombotic complications in T2DM patients, with an emphasis on hypofibrinolysis and its impact on clinical outcomes. We also discuss potential modulators of fibrinolysis in the search for optimal therapy in diabetic patients.

Residual platelet reactivity in low-dose aspirin-treated patients with class 1 obesity

BACKGROUND

Recent data suggest a decreased clinical efficacy of low-dose aspirin in patients weighing ≥70 kg. We therefore investigated the impact of body weight and class 1 obesity on thromboxane generation and platelet reactivity to arachidonic acid (AA) in 316 patients on dual antiplatelet therapy following angioplasty and stenting.

METHODS

Platelet surface expression of P-selectin and activated glycoprotein (GP) IIb/IIIa in response to AA were determined by flow cytometry as sensitive markers of platelet activation. Urinary 11-dehydro-thromboxane B2 (11-dehydro-TXB2) and serum TXB2 were measured by commercially-available immunoassays. On-treatment residual AA-inducible platelet aggregation was assessed by light transmission aggregometry (LTA), the VerifyNow aspirin assay and multiple electrode aggregometry (MEA).

RESULTS

Class 1 obesity was independently associated with increased platelet surface expression of P-selectin and activated GPIIb/IIIa, but not with urinary 11-dehydro-TXB2, serum TXB2, and on-treatment platelet aggregation by all assays. Of all measured parameters, only MEA showed a positive albeit very weak correlation with body weight (r = 0.13, p = 0.02). Furthermore, the results of all tests did not differ significantly between patients without and with a body weight ≥ 70 kg. After adjustment for age and diabetes by multivariate logistic regression analysis, the frequency of high-on treatment residual TXB2 generation and high on-treatment residual AA-inducible platelet reactivity (HRTG/HRPR) did not differ significantly between obese and non-obese patients.

CONCLUSION

Class 1 obesity is associated with enhanced platelet activation in response to AA in patients on dual antiplatelet therapy. This seems to be independent of cyclooxygenase-1 inhibition and does not translate into HRTG/HRPR.

Impact of aging on platelet reactivity in diabetic patients receiving dual antiplatelet therapy

Advanced age and diabetes represent summative conditions in the determination of cardiovascular risk, and especially for the management of dual antiplatelet therapy (DAPT), often requiring balancing between bleeding and thrombotic complications. However, few studies have so far evaluated the impact of age on platelet reactivity and suboptimal platelet inhibition (high-on treatment platelet reactivity-HRPR) on DAPT among diabetic patients, that was, therefore the aim of the present study. In diabetic patients treated with DAPT (ASA + clopidogrel or ticagrelor) platelet reactivity was assessed at 30-90 days post-discharge for an acute coronary syndrome or elective PCI. Aggregation was assessed by multiple-electrode aggregometry. HRPR was defined for values above the lower limit of normality (in non-treated patients). Elderly patients were considered ≥ 75 years of age. We included 462 patients, among them 149 (32.2%) were ≥ 75 years. Elderly patients were more often females (p = 0.006), with lower body size (p = 0.04), acute coronary syndrome at presentation and renal failure (p < 0.001), non-smokers (p = 0.002), in therapy with insulin (p = 0.02) and diuretics (p < 0.001) and lower rate of betablockers (p = 0.02). Age directly related with C reactive protein (p = 0.01), creatinine levels and inversely with hemoglobin (p < 0.001) and triglycerides (p = 0.003). No association was found at linear regression analysis for platelet reactivity and age with different activating stimuli, but for ASPI test (r = 0.12; p = 0.03). No significant difference in HAPR was found in elderly patients (2.4 vs. 3.2%, p = 0.76, OR[95% CI] = 0.45[0.1-2.11], p = 0.31). HRPR for ADP antagonists was similarly not affected by age (30.1% vs. 35.7%, p = 0.28, adjusted OR[95% CI] = 0.78[0.47-1.29], p = 0.33). Comparable results were obtained when considering separately the DAPT strategies with clopidogrel or ticagrelor, or when adjusting our results according to propensity score values. Among diabetic patients receiving dual antiplatelet therapy for an acute coronary syndrome or elective percutaneous coronary intervention, age does not affect platelet reactivity or the rate of high-on treatment platelet reactivity. Similar results were obtained for ASA and clopidogrel or ticagrelor.

Thrombin receptor PAR4 drives canonical NLRP3 inflammasome signaling in the heart

The deleterious effects of diabetes in the heart are increasingly attributed to inflammatory signaling through the NLRP3 (NOD, LRR and PYD domains-containing protein 3) inflammasome. Thrombin antagonists reduce cardiac remodeling and dysfunction in diabetic mice, in part by suppressing fibrin-driven inflammation. The role of cellular thrombin receptor subtypes in this context is not known. We sought to determine the causal involvement of protease-activated receptors (PAR) in inflammatory signaling of the diabetic heart. Mice with diet-induced diabetes showed increased abundance of pro-caspase-1 and pro-interleukin (IL)-1β in the left ventricle (LV), indicating transcriptional NLRP3 inflammasome priming, and augmented cleavage of active caspase-1 and IL-1β, pointing to canonical NLRP3 inflammasome activation. Caspase-11 activation, which mediates non-canonical NLRP3 inflammasome signaling, was not augmented. Formation of the plasma membrane pore-forming protein N-terminal gasdermin D (GDSMD), a prerequisite for IL-1β secretion, was also higher in diabetic vs. control mouse LV. NLRP3, ASC and IL-18 expression did not differ between the groups, nor did expression of PAR1 or PAR2. PAR3 was nearly undetectable. LV abundance of PAR4 by contrast increased with diabetes and correlated positively with active caspase-1. Genetic deletion of PAR4 in mice prevented the diet-induced cleavage of caspase-1, IL-1β and GDSMD. Right atrial appendages from patients with type 2 diabetes also showed higher levels of PAR4, but not of PAR1 or PAR2, than non-diabetic atrial tissue, along with increased abundance of cleaved caspase-1, IL-1β and GSDMD. Human cardiac fibroblasts maintained in high glucose conditions to mimic diabetes also upregulated PAR4 mRNA and protein, and increased PAR4-dependent IL-1β transcription and secretion in response to thrombin, while PAR1 and PAR2 expressions were unaltered. In conclusion, PAR4 drives caspase-1-dependent IL-1β production through the canonical NLRP3 inflammasome pathway in the diabetic heart, providing mechanistic insights into diabetes-associated cardiac thromboinflammation. The emerging PAR4-selective antagonists may provide a feasible approach to prevent cardiac inflammation in patients with diabetes.

Predictors of neutrophil extracellular traps markers in type 2 diabetes mellitus: associations with a prothrombotic state and hypofibrinolysis

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with a hypercoagulable state and increased neutrophil extracellular traps formation (NETosis). We investigated predictors of NETosis and cell death markers in circulating blood and their association with a prothrombotic state in T2DM.

METHODS

In a cross-sectional study involving 113 T2DM patients aged 63.7 ± 8.2 years, we investigated citrullinated histone H3 (H3Cit), cell-free deoxyribonucleic acid (cfDNA), myeloperoxidase, neutrophil elastase, and inflammation markers, along with thrombin generation (TG), plasma clot lysis time (CLT), clot permeability (Ks) and fibrinolysis inhibitors.

RESULTS

On multivariate logistic regression analysis adjusted for age and gender, predictors of high H3Cit (≥ 7.36 ng/mL, upper quartile) were: glycated hemoglobin (HbA1c) ≥ 7.0% and interleukin-6. Interleukin-6 was also found to be a predictor of high cfDNA (≥ 2.84 µg/mL, upper quartile) along with glucose. Citrullinated histone H3 and cfDNA correlated positively with CLT and inversely with Ks, while TG associated solely with cfDNA. These associations were not seen with myeloperoxidase and neutrophil elastase. Patients with previous myocardial infarction (n = 21, 18.6%) had higher H3Cit (+108%, p < 0.001) and cfDNA (+45%, p = 0.022). On multivariable analysis adjusted for potential confounders, H3Cit and cfDNA, along with plasminogen activator inhibitor-1 and concomitant cardiovascular disease, were predictors of CLT. Citrullinated histone H3 alone was a predictor of Ks and only cfDNA was a predictor of peak thrombin generated.

CONCLUSIONS

In T2DM, NETosis detectable in circulating blood is associated with inflammatory state and a prothrombotic state, especially hypofibrinolysis.

Enhanced thrombin generation in patients with arterial hypertension

BACKGROUND

Arterial hypertension is associated with greater risk of cardiovascular diseases and thrombotic complications, suggesting that hypertension is a prothrombotic state.

OBJECTIVES

To investigate the relationship between arterial hypertension and thrombin generation, and between blood pressure level and thrombin generation in hypertensive patients.

METHODS

A total of 165 hypertensive patients and 47 healthy adults controls were include in the study. Thrombin generation was assessed in both groups by the Calibrated Automated Thrombogram (CAT) method. Ambulatory blood pressure monitoring (ABPM) was also performed for all patients in the hypertensive group.

RESULTS

Hypertensive patients had significantly higher levels of ETP and peak heights compared to healthy controls; means of ETP 1720.6 ± 267 and 1544.7 ± 302, respectively (P < 0.001) and means of peak height were 297.26 ± 48 and, 273 ± 53, respectively (P < 0.001). On multivariate linear regression analysis, hypertension remained independently associated with increased ETP (β = 0.185, P = 0.047). Analysis restricted to the hypertensive group with ABPM measurement showed statistically significant correlations between all measures of diastolic blood pressure (DBP) and ETP, and multivariate analysis showed that awake DBP was significantly associated with ETP (β = 0.194 for each 1-mm Hg increase in awake DBP, P = 0.012). Furthermore, hypertensive patients with cardiovascular complications had statistically elevated levels of peak height compared to hypertensive patients without cardiovascular complications.

CONCLUSIONS

Hypertensive patients possess enhanced thrombin generation compared healthy controls. Diastolic blood pressure level is independently correlated with increased thrombin generation in hypertensive patients. These findings suggest that arterial hypertension is a prothrombotic state.

Impaired glucose metabolism is associated with increased thrombin generation potential in patients undergoing angioplasty and stenting

Background

As a strong platelet agonist on the one hand and key molecule in plasmatic coagulation on the other hand, thrombin connects primary and secondary hemostasis. Thrombin generation potential reflects the individual capacity to generate thrombin, and has been associated with the occurrence of thromboembolic events. In the current study, we sought to identify predictors of thrombin generation potential in patients undergoing angioplasty and stenting for atherosclerotic cardiovascular disease.

Methods

Peak thrombin generation potential and area under the curve (AUC) of thrombin generation potential were determined with a commercially available assay in 315 patients on dual antiplatelet therapy 1 day after percutaneous intervention, and in 100 healthy individuals without cardiovascular disease.

Results

Median (interquartile range) peak thrombin generation potential and AUC of thrombin generation potential in the study cohort (n = 315) were significantly higher than in healthy individuals (n = 100) without cardiovascular disease (peak thrombin generation potential: 445.4 nM [354.5–551.8 nM] vs. 174.5 nM [141.2–261.2 nM]; AUC of thrombin generation potential: 5262.7 nM thrombin [4806.6–5756.9 nM thrombin] vs. 3405.2 nM thrombin [3043.6–3747.3 nM thrombin]; both p < 0.001). In patients undergoing angioplasty and stenting, hemoglobin A1c (HbA1c) was the only variable that was independently associated with both, peak thrombin generation potential and AUC of thrombin generation potential (both p ≤ 0.007). In contrast, platelet count and high-sensitivity C-reactive protein were only associated with peak thrombin generation potential, and body mass index and serum creatinine were only associated with AUC of thrombin generation potential after adjustment for covariates by multivariate linear regression analyses (all p < 0.05). Patients with HbA1c ≥ 6% had significantly higher peak thrombin generation potential and AUC of thrombin generation potential than patients with HbA1c < 6% (peak thrombin generation potential: 476.9 nM [385.8–577.9 nM] vs. 423.9 nM [335.8–529.5 nM], p = 0.002; AUC of thrombin generation potential: 5371.8 nM thrombin [4903 – 5899 nM thrombin] vs. 5172.5 nM thrombin [4731.8–5664.7 nM thrombin], p = 0.01). HbA1c ≥ 6% remained independently associated with both parameters of thrombin generation potential after multivariate linear regression analyses (both p ≤ 0.02).

Conclusions

Impaired glucose metabolism is associated with increased thrombin generation potential in patients undergoing angioplasty and stenting for cardiovascular disease.

Viscoelasticity as a measurement of clot structure in poorly controlled type 2 diabetes patients: towards a precision and personalized medicine approach

Objectives

Type 2 diabetes patients (T2D) have a considerably higher cardiovascularrisk, which is closely associated with systemic inflammation, and an accompanying pathologic coagulation system. Due to the complexity of the diabetic profile, we suggest that we need to look at each patient individually and particularly at his or her clotting profile; as the healthiness of the coagulation system gives us an indication of the success of clinical intervention.

Results

T2D coagulability varied markedly, although there were no clear difference in medication use and the standards of HbA1c levels.

Research design and methods

Our sample consisted of 90 poorly controlled T2D and 71 healthy individuals. We investigated the medication use and standards of HbA1c levels of T2D and we used thromboelastography (TEG) and scanning electron microscopy (SEM) to study their clot formation.

Conclusion

The latest NIH guidelines suggest that clinical medicine should focus on precision medicine, and the current broad understanding is that precision medicine may in future, provide personalized targets for preventative and therapeutic interventions. Here we suggest a practical example where TEG can be used as an easily accessible point-of-care tool to establish a comprehensive clotting profile analysis for T2D patients; and additionally may provide valuable information that may be used in the envisaged precision medicine approach. Only by closely following each individual patient's progress and healthiness and thereby managing systemic inflammation, will we be able to reduce this pandemic.

Peripheral Arterial Disease in Type 2 Diabetes Is Associated with an Increase in Fibrinogen Levels

BACKGROUND

The present study is undertaken to investigate the fibrinogen levels in type 2 diabetes mellitus (T2DM) and its relation to peripheral artery disease (PAD) based on a more accurate and applied noninvasive measurements of duplex ultrasonography.

METHODS

We performed a cross-sectional study including 1096 T2DM patients (474 males and 622 females). The odds ratios (ORs) and 95% confidence intervals (CIs) were presented to show the association between PAD and fibrinogen in the subjects divided by fibrinogen levels quarterly. Furthermore, the univariate and multiple logistic analyses were performed to explore the correlation between PAD and fibrinogen levels, individual components in the cross-sectional study.

RESULTS

Finally, 887 (80.9%) T2DM patients meet the diagnostic criteria of PAD and these patients had considerably higher serum fibrinogen concentration than non-PAD group (P < 0.001). Multiple logistic analyses revealed that higher fibrinogen quartiles were positively related with the development of PAD in the adjusted model. After adjusting for known confounding parameters, the ORs for PAD were 1.993 (95% CI: 1.322-3.005, P < 0.001), 2.469 (95% CI: 1.591-3.831, P < 0.001), and 2.942 (95% CI, 1.838-4.711, P < 0.001) for Q2, Q3, and Q4, respectively (all P values <0.05).

CONCLUSIONS

Our results suggest that serum fibrinogen concentration can be considered as an independent risk factor for PAD in T2DM patients.

Lipopolysaccharide-binding protein (LBP) reverses the amyloid state of fibrin seen in plasma of type 2 diabetics with cardiovascular co-morbidities

Type 2 diabetes (T2D) has many cardiovascular complications, including a thrombotic propensity. Many such chronic, inflammatory diseases are accompanied (and may be exacerbated, and possibly even largely caused) by amyloid fibril formation. Recognising that there are few strong genetic associations underpinning T2D, but that amyloidogenesis of amylin is closely involved, we have been seeking to understand what might trigger the disease. Serum levels of bacterial lipopolysaccharide are raised in T2D, and we recently showed that fibrin(ogen) polymerisation during blood clotting can be affected strongly by LPS. The selectivity was indicated by the regularisation of clotting by lipopolysaccharide-binding protein (LBP). Since coagulopathies are a hallmark of T2D, we wondered whether they might too be caused by LPS (and reversed by LBP). We show here, using SEM and confocal microscopy, that platelet-poor-plasma from subjects with T2D had a much greater propensity for hypercoagulability and for amyloidogenesis, and that these could both be reversed by LBP. These data imply that coagulopathies are an important feature of T2D, and may be driven by ‘hidden’ LPS. Given the prevalence of amyloid formation in the sequelae of diabetes, this opens up novel strategies for both the prevention and treatment of T2D.

Hypofibrinolysis in diabetes: a therapeutic target for the reduction of cardiovascular risk

An enhanced thrombotic environment and premature atherosclerosis are key factors for the increased cardiovascular risk in diabetes. The occlusive vascular thrombus, formed secondary to interactions between platelets and coagulation proteins, is composed of a skeleton of fibrin fibres with cellular elements embedded in this network. Diabetes is characterised by quantitative and qualitative changes in coagulation proteins, which collectively increase resistance to fibrinolysis, consequently augmenting thrombosis risk. Current long-term therapies to prevent arterial occlusion in diabetes are focussed on anti-platelet agents, a strategy that fails to address the contribution of coagulation proteins to the enhanced thrombotic milieu. Moreover, antiplatelet treatment is associated with bleeding complications, particularly with newer agents and more aggressive combination therapies, questioning the safety of this approach. Therefore, to safely control thrombosis risk in diabetes, an alternative approach is required with the fibrin network representing a credible therapeutic target. In the current review, we address diabetes-specific mechanistic pathways responsible for hypofibrinolysis including the role of clot structure, defects in the fibrinolytic system and increased incorporation of anti-fibrinolytic proteins into the clot. Future anti-thrombotic therapeutic options are discussed with special emphasis on the potential advantages of modulating incorporation of the anti-fibrinolytic proteins into fibrin networks. This latter approach carries theoretical advantages, including specificity for diabetes, ability to target a particular protein with a possible favourable risk of bleeding. The development of alternative treatment strategies to better control residual thrombosis risk in diabetes will help to reduce vascular events, which remain the main cause of mortality in this condition.

Procoagulant activity in patients with combined type 2 diabetes and coronary artery disease: No effects of long-term exercise training

We investigated the effects of 12-month exercise training on hypercoagulability in patients with combined type 2 diabetes mellitus and coronary artery disease. Associations with severity of disease were further explored. Patients ( n = 131) were randomized to exercise training or a control group. Blood was collected at inclusion and after 12 months. Tissue factor, free and total tissue factor pathway inhibitor, prothrombin fragment 1 + 2 (F1 + 2) and D-dimer were determined by enzyme-linked immunosorbent assay and ex vivo thrombin generation by the calibrated automated thrombogram assay. Tissue factor and ex vivo thrombin generation increased from baseline to 12 months ( p < 0.01, all), with no significant differences in changes between groups. At baseline, free and total tissue factor pathway inhibitor significantly correlated to fasting glucose ( p < 0.01, both) and HbA1c ( p < 0.05, both). In patients with albuminuria ( n = 34), these correlations were strengthened, and elevated levels of D-dimer, free and total tissue factor pathway inhibitor ( p < 0.01, all) and decreased ex vivo thrombin generation ( p < 0.05, all) were observed. These results show no effects of exercise training on markers of hypercoagulability in our population with combined type 2 diabetes mellitus and coronary artery disease. The association between poor glycaemic control and tissue factor pathway inhibitor might indicate increased endothelial activation. More pronounced hypercoagulability and increased tissue factor pathway inhibitor were demonstrated in patients with albuminuria.

Abdominal adiposity contributes to adverse glycemic control and albuminuria in Chinese type 2 diabetic patients: A cross-sectional study

BACKGROUND

Abdominal adipose tissue plays an important role in the development of type 2 diabetes. However, few data have suggested its role in the prognosis of diabetes. This study aimed to investigate the association between waist-hip ratio (WHR), glycemic control, and early nephropathy in Chinese type 2 diabetic patients.

METHODS

A cross-sectional study was conducted in 1709 previously- and newly-diagnosed diabetic patients nested in a cohort study consisting of 10 375 participants aged ≥40 years in Shanghai, China. General characteristics through questionnaire, anthropometric measures, and biochemical results were recorded. Statistical analysis was performed by SPSS v20.0.

RESULTS

Each quartile increase in WHR was significantly associated with a fasting plasma glucose (FPG) ≥ 126 mg/dl [OR (95% CI):1.18 (1.06-1.30)], an HbA1c ≥ 7.0% [1.21 (1.08-1.35)], and a HOMA-IR ≥ 2.5 [1.30 (1.16-1.46)] after multivariable adjustments. WHR was not associated with a 2h PG ≥ 200mg/dl [1.13 (0.97-1.31)]. The risk for increased albuminuria (UACR ≥10.18mg/g) was also significantly associated with higher WHR after adjustment for HbA1c [1.14 (1.02-1.27)]. However, no significant relationship was seen between WHR and an estimated glomerular filtration rate < 90 ml/min per 1.73 m² . Interactions of sex, or physical activity with WHR in association with glycemic control and increased albuminuria were found (P values for interaction <0.05).

CONCLUSIONS

These data demonstrated an independent role of abdominal adipose tissue in glycemic control and renal complications of type 2 diabetes. Interventions aiming to reduce abdominal adipose tissue may have additional benefits.

Correlation between the plasma fibrinogen concentration and coronary heart disease severity in Moroccan patients with type 2 diabetes. Prospective study

AIM

The present study aims at determining the relationship between the plasma fibrinogen concentration and the severity of coronary heart disease in type 2 diabetic patients.

METHODS

Prospective analytical survey, based on a sample of 120 subjects divided in four groups: 30 non diabetic coronary patients (G1), 30 coronary diabetic patients (G2), 30 non-coronary diabetic patients (G3), and 30 healthy subjects (G4).

RESULTS

The average age was 59.58±7.88 years; female gender predominated by 52.5%. The plasma fibrinogen concentration corresponded to 3.46g/L±0.86 in G1; 3.73g/L±1.11 in G2; 3.06g/L±0.98 in G3 and 2.46g/L±0.51 in G4; with a significant difference between the four groups (P=0.001). The plasma fibrinogen concentration increased in parallel with the cardiovascular risk (P=0.0001); there was also a significant correlation between the plasma fibrinogen concentration and the clinical and para-clinical coronary disease severity (respectively P=0.005 and P=0.0001). A positive correlation between the plasma fibrinogen concentration and hyperglycemia (P=0.035) was found in G4. But no correlation with the lipids parameters, except for the low density-lipoproteins in G3 (P=0.035).

CONCLUSION

In the Moroccan population, the plasma fibrinogen concentration was positively and significantly correlated with the coronary heart disease severity.

Markers of thrombin generation are associated with myocardial necrosis and left ventricular impairment in patients with ST-elevation myocardial infarction

Introduction

Platelet activation, thrombin generation and fibrin formation play important roles in intracoronary thrombus formation, which may lead to acute myocardial infarction.

We investigated whether the prothrombotic markers D-dimer, pro-thrombin fragment 1 + 2 (F1 + 2) and endogenous thrombin potential (ETP) are associated with myocardial necrosis assessed by Troponin T (TnT), and left ventricular impairment assessed by left ventricular ejection fraction (LVEF) and N-terminal pro b-type natriuretic peptide (NT-proBNP).

Materials/Methods

Patients (n = 987) with ST-elevation mycardial infarction (STEMI) were included. Blood samples were drawn at a median time of 24 h after onset of symptoms.

Results

Statistically significant correlations were found between both peak TnT and D-dimer (p < 0.001) and F1 + 2 (p < 0.001), and between NT-proBNP and D-dimer (p = 0.001) and F1 + 2 (p < 0.001). When dividing TnT and NT-proBNP levels into quartiles there were significant trends for increased levels of both markers across quartiles (all p < 0.001) D-dimer remained significantly associated with NT-proBNP after adjustments for covariates (p = 0.001) whereas the association between NTproBNP and F1 + 2 was no longer statistically significant (p = 0.324).

A significant inverse correlation was found between LVEF and D-dimer (p < 0.001) and F1 + 2 (p = 0.013). When dichotomizing LVEF levels at 40 %, we observed significantly higher levels of both D-dimer (p < 0.001) and F1 + 2 (p = 0.016) in the group with low EF (n = 147).

Summary/conclusion

In our cohort of STEMI patients we demonstrated that levels of D-dimer and F1 + 2 were significantly associated with myocardial necrosis as assessed by peak TnT. High levels of these coagulation markers in patients with low LVEF and high NTproBNP may indicate a hypercoagulable state in patients with impaired myocardial function.

The simultaneous occurrence of both hypercoagulability and hypofibrinolysis in blood and serum during systemic inflammation, and the roles of iron and fibrin(ogen)

Although the two phenomena are usually studied separately, we summarise a considerable body of literature to the effect that a great many diseases involve (or are accompanied by) both an increased tendency for blood to clot (hypercoagulability) and the resistance of the clots so formed (hypofibrinolysis) to the typical, 'healthy' or physiological lysis. We concentrate here on the terminal stages of fibrin formation from fibrinogen, as catalysed by thrombin. Hypercoagulability goes hand in hand with inflammation, and is strongly influenced by the fibrinogen concentration (and vice versa); this can be mediated via interleukin-6. Poorly liganded iron is a significant feature of inflammatory diseases, and hypofibrinolysis may change as a result of changes in the structure and morphology of the clot, which may be mimicked in vitro, and may be caused in vivo, by the presence of unliganded iron interacting with fibrin(ogen) during clot formation. Many of these phenomena are probably caused by electrostatic changes in the iron-fibrinogen system, though hydroxyl radical (OH˙) formation can also contribute under both acute and (more especially) chronic conditions. Many substances are known to affect the nature of fibrin polymerised from fibrinogen, such that this might be seen as a kind of bellwether for human or plasma health. Overall, our analysis demonstrates the commonalities underpinning a variety of pathologies as seen in both hypercoagulability and hypofibrinolysis, and offers opportunities for both diagnostics and therapies.

High coagulation factor levels and low protein C levels contribute to enhanced thrombin generation in patients with diabetes who do not have macrovascular complications

AIMS

A prothrombotic state characterized by activation of the coagulation system has been implicated in the pathogenesis of vascular complications in diabetes mellitus. Recently, a thrombin generation assay was introduced as a laboratory assessment of global hemostatic potential. We used this thrombin generation assay to investigate global hemostatic potential in patients with diabetes who did not have macrovascular complications.

METHODS

This study was a prospective case-control study comparing 89 patients with diabetes with 49 healthy controls. The thrombin generation assay was conducted with the calibrated automated thrombogram using tissue factor with or without the addition of thrombomodulin, giving values for lag time, endogenous thrombin potential, and peak thrombin.

RESULTS

Patients with diabetes showed hypercoagulability, as detected by the thrombin generation assay, compared with healthy controls. Correspondingly, high levels of coagulation factors (II, V, VII, VIII, and X) and low levels of anticoagulant (protein C) were major contributing factors in this hypercoagulability. Interestingly, a high blood glucose level was correlated with shortened clotting time, reflecting the association between hyperglycemia and hypercoagulability. Patients who were taking statins or angiotensin receptor blockers showed decreased endogenous thrombin potential ratio and increased protein C levels, suggesting relative hypocoagulability.

CONCLUSIONS

Patients with diabetes showed hypercoagulability, high levels of coagulation factors, and low levels of protein C. Further study is required to investigate how this hemostatic potential may be used to guide physicians toward more effective management of hemostatic complications.

Zucker Diabetic Fatty rats exhibit hypercoagulability and accelerated thrombus formation in the Arterio-Venous shunt model of thrombosis

INTRODUCTION

Diabetes is a significant risk factor for thrombosis. The present study aimed at assessing coagulability, platelet reactivity, and thrombogenicity of the diabetic female Zucker Diabetic Fatty (ZDF) rat model and its relevance in studying antithrombotic mechanisms.

MATERIALS AND METHODS

The basal coagulant state in ZDF rats was evaluated by clotting times, thromboelastography, and thrombin generation assay. A 14-day treatment with dapagliflozin in ZDF rats was pursued to investigate if glycemic control can improve coagulability. Thrombus formation in the Arterio-Venous (A-V) shunt model and the FeCl3-induced arterial thrombosis model was studied, with the antithrombotic effect of apixaban in the former model further investigated.

RESULTS

ZDF rats exhibited significantly shortened clotting times, enhanced thrombin generation, and decreased fibrinolysis at baseline. Effective glycemic control achieved with dapagliflozin did not improve any of these parameters. ZDF rats displayed accelerated thrombus formation and were amenable to apixaban treatment in the A-V shunt model albeit with less sensitivity than normal rats. ZDF rats exhibited less platelet aggregation in response to ADP, collagen and PAR-4, and attenuated thrombotic response in the FeCl3 model.

CONCLUSIONS

ZDF rats are at a chronic hypercoagulable and hypofibrinolytic state yet with compromised platelet reactivity. They display accelerated and attenuated thrombosis in the A-V shunt and FeCl3 model of thrombosis, respectively. Results shed new light on the pathophysiology of the ZDF rat model and illustrate its potential value in translational research on anticoagulant agents in diabetics. Caution needs to be exerted in utilizing this model in assessing antiplatelet mechanisms in diabetes-associated atherothrombosis.

Dipeptidyl peptidase-4 inhibitors: multitarget drugs, not only antidiabetes drugs

Dipeptidyl peptidase (DPP)-4 inhibitors are a new class of antidiabetic agents that reduce blood glucose by preventing the degradation of the endogenous incretin hormones glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide. Protection by DPP-4 inhibitors of β-cell function has been demonstrated in patients with type 2 diabetes. Because DPP-4 is an enzyme widely expressed in humans, DPP-4 inhibitors are speculated to be multitarget agents. However, other potential therapeutic benefits of DPP-4 inhibitors remain unknown. Recently, some therapeutic effects of DPP-4 inhibitors, such as immune regulation, cardiovascular protection, and anti-inflammatory effects, have been observed. This article provides a systematic and comprehensive review of current research into the newly found effects and mechanism of action of DPP-4 inhibitors in a therapeutic context.

Influence of fibrinogen and C-RP on progression of peripheral arterial disease in type 2 diabetes: a preliminary report

Background

Limited studies have suggested that inflammatory biomarkers play a role in the initiation and progression of atherosclerosis in diabetic patients. This study assesses the effect of inflammatory biomarkers: fibrinogen and C-reactive protein (C-RP) on the progression of peripheral arterial disease (PAD) in type 2 diabetic (T2D) patients.

Methods

Sixty two patients with T2D and PAD (mean age 60.28 ± 27 years and diabetes duration of 8.58 ± 6.17 years) were enrolled in a cohort prospective study of 36 months. Ankle-brachial index (ABI) was measured in all patients at baseline and after 36 months. Multiple linear regression analysis was used to determine the predictivity of variables for fibrinogen, C-RP, plasma lipid fractions, fasting plasma glucose, Body Mass Index (BMI), duration of diabetes status and the age on changes in ABI value.

Results

Linear regression analysis defined F as a predictor for endpoint value of ABI (β = 0.469, p = 0.007). Value of C-RP determinates change of minimal value of ABI (β = 0.449, p = 0.037) and change of mean ABI per year (β = 0.442, p = 0.025).

Conclusion

Our data indicate that plasma determination of fibrinogen and C-RP might have a clinical implication in defining the process of progression of PAD in T2D population.