Hyperglycemia: a prothrombotic factor?

Plasma levels of mannan-binding lectin-associated serine proteases MASP-1 and MASP-2 are elevated in type 1 diabetes and correlate with glycaemic control

There is increasing evidence that the complement system plays an important role in diabetes and the development of diabetic vascular complications. In particular, mannan-binding lectin (MBL) levels are elevated in diabetes patients, and diabetes patients with diabetic nephropathy have higher MBL levels than diabetes patients with normal renal function. The MBL-associated serine proteases (MASPs) MASP-1, MASP-2 and MASP-3 and MBL-associated protein MAp44 have not yet been studied in diabetes patients. We therefore measured plasma levels of MASP-1, MASP-2, MASP-3 and MAp44 in 30 children with type 1 diabetes mellitus (T1DM) and 17 matched control subjects, and in 45 adults with T1DM and 31 matched control subjects. MASP-1 and MASP-2 levels were significantly higher in children and adults with T1DM than in their respective control groups, whereas MASP-3 and MAp44 levels did not differ between patients and controls. MASP-1 and MASP-2 levels correlated with HbA1c, and MASP levels decreased when glycaemic control improved. Because MASP-1 and MASP-2 have been shown to interact directly with blood coagulation, elevated levels of these proteins may play a role in the enhanced thrombotic environment and consequent vascular complications in diabetes.

Lowering blood glucose during hip surgery does not influence coagulation activation

Background

Hyperglycaemia during and after hip surgery is associated with coagulation activation and an increased risk of venous thromboembolism. Whether lowering of glucose levels during hip surgery diminishes coagulation activation is unknown. We investigated the efficacy of the human GLP-1 analogue liraglutide to lower glucose during and after hip surgery and studied its influence on coagulation activation.

Methods

A total of 37 obese subjects who underwent hip surgery were randomized to subcutaneous liraglutide or placebo for 4 consecutive days, starting one day prior to surgery. Glucose levels and coagulation indices at three fixed time-points (pre-operative, 2 h post-operative and 3 days post-operative) were measured.

Results

Liraglutide reduced glucose at day three post-surgery (median glucose (IQR) liraglutide 5.5 (5.2–5.7) vs. placebo 5.8 (5.5–6.2); difference 0.3 mmol/L, P = 0.04). Changes in 6 out of 8 coagulation indices studied did not differ between the two groups. Only D-dimer levels were significantly lower in the liraglutide group at day three post-surgery and FVIII levels were significantly higher in the liraglutide group 2 h post-surgery.

Conclusion

Although the human GLP-1 analogue liraglutide moderately reduced post-operative blood glucose levels in non-diabetic and prediabetic obese patients undergoing elective hip surgery, no changes were observed with respect to coagulation activation.

•

Hyperglycaemia during hip surgery is associated with venous thromboembolism.

•

We examined the effect of perioperative glucose lowering on coagulation.

•

Perioperative glucose lowering was realized using the GLP-1 antagonist liraglutide.

•

Liraglutide moderately reduced glucose levels in non-diabetic and prediabetic hip surgery patients.

•

No effect of glucose lowering therapy on coagulation was found.

Unfavorable neurological outcome in diabetic patients with acute ischemic stroke is associated with incomplete recanalization after intravenous thrombolysis

Objective

To assess the impact of diabetes on neurological outcome and recanalization in acute ischemic stroke (AIS) after intravenous thrombolysis (IVT).

Methods

Clinical data of 419 consecutive patients with AIS who received IVT between June 2009 and April 2014. Based on the medical history and new diagnosis, the patients were divided into groups with and without diabetes. Neurological outcomes at 24 h, 7 days and 3 months after IVT were evaluated. Favorable outcome was defined as National Institutes of Health Stroke Scale (NIHSS) score decrease ≥4 points from baseline or 0 at 24 h, NIHSS decrease ≥8 points or 0 at day 7, or modified Rankin scale ≤1 at 3 months after IVT. Recanalization on non-invasive imaging was evaluated in patients with large vessel occlusion (LVO) according to thrombolysis in myocardial infarction grades.

Results

Among 419 patients, 98 (23.4%) had diabetes. Multivariable analyses showed that comorbidity of diabetes was an independent predictor of unfavorable outcome at 24 h (OR=0.534, 95% CI 0.316 to 0.903, p=0.019), at day 7 (OR=0.382, 95% CI 0.220 to 0.665, p=0.001), and at 3 months (OR=0.464, 95% CI 0.266 to 0.808, p=0.007). In patients with LVO, diabetes was an independent predictor of incomplete recanalization 24 h after IVT (OR=0.268, 95% CI 0.075 to 0.955, p=0.042).

Conclusions

Diabetic patients with AIS had unfavorable neurological outcome, potentially linked to incomplete recanalization after IVT.

Asiatic acid and maslinic acid protected heart via anti-glycative and anti-coagulatory activities in diabetic mice

The cardiac protective effects of asiatic acid (AA) and maslinic acid (MA) in diabetic mice were examined.

Incidence, causes and predictors of neurological deterioration occurring within 24 h following acute ischaemic stroke: a systematic review with pathophysiological implications

Early neurological deterioration (END) following ischaemic stroke is a serious event with manageable causes in only a fraction of patients. The incidence, causes and predictors of END occurring within 24 h of acute ischaemic stroke (END24) have not been systematically reviewed. We systematically reviewed Medline and Embase from January 1990 to April 2013 for all studies on END24 following acute ischaemic stroke (<8 h from onset). We recorded the incidence and presumed causes of and factors associated with END24. Thirty-six studies were included. Depending on the definition used, the incidence of END24 markedly varied among studies. Using the most widely used change in National Institutes of Health Stroke Scale ≥4 definition, the pooled incidence was 13.8% following thrombolysis, ascribed to intracranial haemorrhage and malignant oedema each in ∼20% of these. As other mechanisms were rarely reported, in the majority no clear cause was identified. Few data on END24 occurring in non-thrombolysed patients were available. Across thrombolysed and non-thrombolysed samples, the strongest and most consistent admission predictors were hyperglycaemia, no prior aspirin use, prior transient ischaemic attacks, proximal arterial occlusion and presence of early CT changes, and the most consistent 24 h follow-up associated factors were no recanalisation/reocclusion, large infarcts and intracranial haemorrhage. Finally, END24 was strongly predictive of poor outcome. The above findings are discussed with emphasis on END without a clear mechanism. Data on incidence and predictors of the latter subtype is scarce, and future studies using systematic imaging protocols should address its underlying pathophysiology. This may in turn lead to rational preventative and therapeutic measures for this ominous event.

[Complications associated with hyperglycemia in liver transplant patients]

BACKGROUND

Hyperglycemia is a frequent phenomenon in hospitalized patients that is associated with negative outcomes. It is common in liver transplant patients as a result of stress and is related to immunosuppressant drugs. Although studies are few, a history of diabetes and the presentation of hyperglycemia during liver transplantation have been associated with a higher risk for rejection.

AIMS

To analyze whether hyperglycemia during the first 48hours after liver transplantation was associated with a higher risk for infection, rejection, or longer hospital stay.

METHODS

A retrospective cohort study was conducted on patients above the age of 15years that received a liver transplant. Hyperglycemia was defined as a value above 140mg/dl and it was measured in three different manners (as an isolated value, as a mean value, and as a weighted value over time). The relation of hyperglycemia to a risk for acute rejection, infection, or longer hospital stay was evaluated.

RESULTS

Some form of hyperglycemia was present in 94% of the patients during the first 48 post-transplantation hours, regardless of its definition. There was no increased risk for rejection (OR: 1.49; 95%CI: 0.55-4.05), infection (OR: 0.62; 95%CI: 0.16-2.25), or longer hospital stay between the patients that presented with hyperglycemia and those that did not.

CONCLUSIONS

Hyperglycemia during the first 48hours after transplantation appeared to be an expected phenomenon in the majority of patients and was not associated with a greater risk for rejection or infection and it had no impact on the duration of hospital stay.

Hyperglycemia in patients referred for cardiac catheterization is associated with preexisting diabetes rather than a stress-related phenomenon: a prospective cross-sectional study

BACKGROUND

An increased serum glucose level in patients with acute coronary syndrome (ACS) is associated with adverse clinical outcome. This hyperglycemia has been attributed, at least in part, to acute stress reaction. Our objective was to determine whether hyperglycemia is a stress-related phenomenon or whether it represents a more sustained and possibly significant background dysglycemia.

HYPOTHESIS

Hyperglycemia in patients undergoing coronary angiography is related to background dysglycemia.

METHODS

Blood samples were obtained at the time of cardiac catheterization. Patients with hemoglobin A1c >6.5% were excluded to avoid patients with chronic glucose levels above 135 mg/dL. A logistic regression model was created to assess the influence of different variables on hyperglycemia (glucose levels above 140 mg/dL). We also evaluated the effect of glucose levels above 140 mg/dL on major adverse cardiovascular events (MACEs) up to 36 months.

RESULTS

There were 2554 consecutive patients prospectively recruited. Serum glucose levels above 140 mg/dL was a strong predictor of MACE (hazard ratio: 2.2, 95% confidence interval [CI]: 1.3-3.6, P = 0.002). Both diabetes mellitus and ACS were associated with hyperglycemia (glucose levels above 140 mg/dL). Nevertheless, the incidence of hyperglycemia was doubled in diabetic patients (odds ratio [OR]: 9.4, 95% CI: 3.9-22.4, P < 0.001) compared with patients with ACS (OR: 4.6, 95% CI: 2.3-9.0, P < 0.001). Combining both conditions was associated with a high likelihood of elevated glucose levels (OR: 15.5, 95% CI: 7.4-32.9, P < 0.001).

CONCLUSIONS

Hyperglycemia in patients undergoing cardiac catheterization is a strong predictor of adverse outcome. It is mainly related to background dysglycemia and to a lesser extent to the acute stress accompanying ACS.

Glycemia (hemoglobin A1c) and incident venous thromboembolism in the Atherosclerosis Risk in Communities cohort study

Diabetes has been inconsistently associated with increased risk of venous thromboembolism (VTE) and there is little direct evidence on the associations of glycemia levels with VTE. We used data from the Atherosclerosis Risk in Communities study to test the hypothesis that glycemia, as measured by hemoglobin A1c (A1c), is positively associated with VTE. Participants aged 45-64 years (n = 12,298) had A1c measured in 1990 and were followed for incident VTE (n = 345) through 2005. Because A1c is affected by diabetes treatment, analyses were stratified by history of diagnosed diabetes. Owing to evidence of non-linearity, we categorized A1c according to clinical cut-points: <5.7, 5.7-6.4, and ≥ 6.5% in those with no diagnosed diabetes; <7.0 and ≥ 7.0% in those with diagnosed diabetes. After adjustment for potential confounders, the hazard ratios (95% CIs) for VTE across increasing A1c categories were 1 (referent), 1.02 (0.77, 1.35) and 0.72 (0.41, 1.29) for those without diagnosed diabetes, and 1.30 (0.77, 2.17) and 1.41 (0.95, 2.09) for those with diagnosed diabetes. To explore the relation, we employed various models to adjust for potential confounding variables and modeled A1c as tertiles. We consistently found elevated hazard ratios in those with diagnosed diabetes, though the association was not statistically significant in every model. Hazard ratios in those without diagnosed diabetes were close to 1. In conclusion, our results are mildly suggestive that diagnosed diabetes and high levels of glucose, per se, may increase the risk of VTE. Elevated glucose was not related to VTE in those without diagnosed diabetes.

A novel activating ABCC8 mutation underlying neonatal diabetes mellitus in an infant presenting with cerebral sinovenous thrombosis

Neonatal diabetes mellitus is a rare clinical condition, which develops most commonly secondary to mutations in KCNJ11 and ABCC8 genes encoding ATP-sensitive K+ channels. Patients are typically diagnosed with hyperglycemia-related symptoms in the first 6 months of life and rarely with ketoacidosis. In this article, we report an infant who presented with focal clonic convulsion and thereafter was diagnosed with neonatal diabetes mellitus and thrombi in cerebral venous sinus. In this patient, after a molecular analysis of the ABCC8 gene revealed a novel heterozygous missense mutation (p.D424V), a successful transition from insulin to sulfonylurea treatment was made.

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.

Effects of warfarin and L-carnitine on hemostatic function and oxidative stress in streptozotocin-induced diabetic rats

Diabetes mellitus (DM) is a complex progressive disease characterized by hyperglycemia and a high risk of atherothrombotic disorders affecting the coronary, cerebral, and peripheral arterial trees. Oxidative stress is reported in diabetic patients. We investigated the hemostatic functions and oxidative stress in streptozotocin (STZ)-induced diabetic rats and the effects of warfarin and L-carnitine on those parameters. Forty male Sprague-Dawley rats were divided into four groups: control, DM, and DM received warfarin or L-carnitine. In all rats, blood glucose, insulin, hemoglobin A1c (HbA1c), fibrinogen, factor VII (FVII), plasminogen activator inhibitor-1 (PAI-1), fibrin degradation products (FDP), protein C, antithrombin III (ATIII), malondialdehydes (MDA), and antioxidants (superoxide dismutase, catalase, glutathione peroxidase, glutathione) were measured. Also, prothrombin time (PT), activated partial thromboplastin time (aPTT), coagulation time, and platelet aggregation were evaluated. In diabetic rats, plasma glucose, HbA1c, MDA, fibrinogen, FVII, FDP, PAI-1, and platelet aggregation increased while insulin, PT, aPTT, coagulation time, protein C, ATIII, and antioxidants decreased. Warfarin administration to diabetic rats decreased FVII and FDP and increased PT, aPTT, and coagulation time with no effect on MDA, antioxidants, PAI-1, protein C, ATIII, and platelet aggregation. On the other hand, L-carnitine decreased fibrinogen, FVII, FDP, PAI-1, MDA, and platelet aggregation and increased PT, aPTT, coagulation time, protein C, ATIII, and antioxidants in diabetic rats. Therefore, we concluded that hyperglycemia plays an important role in hypercoagulation state and oxidative stress in STZ-induced DM. While L-carnitine improves oxidative stress and decreases the hypercoagulation state in DM, warfarin normalizes the hypercoagulation state with no effect on oxidative stress.

Annexin V expression and anti-annexin V antibodies in type 1 diabetes

BACKGROUND

Annexin V (AnxV) has potent anticoagulant properties and regulatory functions for apoptosis and inflammation. Antibodies against annexin V (anti-AnxVs) may inhibit AnxV functions, leading to thrombosis during autoimmune diseases. Type 1 diabetes is an autoimmune disease and related with an ongoing autoimmune inflammation and thrombotic complications. There is no study evaluating anti-AnxVs/AnxV in a disease setting.

OBJECTIVE

The aim of this study was to evaluate the status of AnxV and anti-AnxVs in patients with type 1 diabetes.

METHODS

One hundred twenty-one patients with type 1 diabetes and 92 healthy controls were included in this study. Serum levels of AnxV and anti-AnxVs and expression of the AnxV gene and its common polymorphism in Kozak sequence (-1C>T) were studied. As a functional assay, the binding capacity of AnxV to platelets was evaluated.

RESULTS

As compared with controls, type 1 diabetic patients had significantly low serum AnxV levels and AnxV gene expression. The number of anti-AnxV positivity and their serum levels were significantly higher in type 1 diabetic patients than controls. AnxV binding to platelets were significantly decreased in the type 1 diabetic patients. The frequencies of the -1C>T polymorphism of AnxV gene did not differ between groups.

CONCLUSIONS

This study demonstrated the significant changes in AnxV levels and its function in type 1 diabetic patients. These results support the hypothesis that the defective AnxV system may have a role in ongoing autoimmune activity and the development of thrombotic complications in type 1 diabetes. Further studies are necessary to elucidate the clinical impact of anti-AnxVs and dysregulated AnxV function in type 1 diabetes.

Hyperglycemia following recovery from hypoglycemia worsens endothelial damage and thrombosis activation in type 1 diabetes and in healthy controls

BACKGROUND AND AIMS

Hypoglycemia produces thrombosis activation, but little attention has been paid to the effects of hyperglycemia following recovery from hypoglycemia on thrombosis activation.

METHODS AND RESULTS

In both twenty-two healthy subjects and twenty-one matched persons with type 1 diabetes, recovery from a 2-h induced hypoglycemia was obtained by reaching normo-glycemia or hyperglycemia for another 2 h. After this, normal glycemia was maintained for the following 6 h. Hyperglycemia after hypoglycemia was also repeated with the concomitant infusion of vitamin C. In both controls and people with diabetes, the recovery with normo-glycemia was accompanied by a significant improvement of Von Willebrand factor (vWF), prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin III-complexes (TAT), P-selectin, plasminogen activator inhibitor-1 (PAI-1), nitrotyrosine and 8-iso-prostaglandin F2α (8-iso-PGF2α) (p < 0.01 vs hypoglycemia for all the parameters), all directly affected by hypoglycemia itself (p < 0.01 vs baseline for all the parameters). On the contrary, the recovery with hyperglycemia after hypoglycemia worsens all these parameters (p < 0.01 vs normoglycemia for all the parameters), an effect persisting even after the additional 6 h of normo-glycemia. The effect of hyperglycemia following hypoglycemia was partially counterbalanced when vitamin C was infused (p < 0.01 vs hyperglycemia alone for all the parameters), suggesting that hyperglycemia following hypoglycemia may activate thrombosis through the oxidative stress production.

CONCLUSION

This study shows that, in type 1 diabetes as well as in controls, the way in which recovery from hypoglycemia takes place could play an important role in favoring the activation of thrombosis and oxidative stress, widely recognized cardiovascular risk factors.

Quantification of fibrin in blood thrombi formed in hemodialysis central venous catheters: a pilot study on 43 CVCs

PURPOSE

Fibrin deposition and thrombotic occlusion represent a serious cause of access dysfunction in hemodialysis central venous catheters (CVCs). The aim of this work was to define and apply a method for imaging and quantifying fibrin in thrombi formed into the side holes of CVCs.

METHODS

Forty-three CVCs removed from a cohort of dialyzed patients were analyzed in this pilot study. Hematoxylin and eosin and a modified Carstair's staining were applied on permanent thrombus sections. Fluorescence microscopy and image analysis were performed to quantify the fibrin amount.

RESULTS

Highly fluorescent areas were invariably associated with fibrin by Carstair's method. The deposition of concentric layers of fibrin and erythrocytes was easily identified by fluorescence microscopy, showing growth features of the thrombus. Fibrin amount in diabetic patients was significantly higher than that in nondiabetic patients with median (interquartile range) values of 51% (47-68%) and 44% (30-54%), respectively (p=0.032). No significant difference in fibrin content was found by grouping data according to catheter type, permanence time, insertion site and dialysis vintage. Higher variability in fibrin values was found in thrombi from CVCs removed after 1-15 days compared with 16-60 days. A trend of an increase in fibrin amount in thrombi was noted according to blood platelet count at CVC insertion.

CONCLUSIONS

The analytical method presented here proved to be a rapid and effective way for quantifying fibrin content in thrombi formed on CVCs with potential application in future clinical studies.

Association of activated partial thromboplastin time and fibrinogen level in patients with type II diabetes mellitus

Background

Patients with diabetes mellitus have a high risk of atherothrombotic events. Diabetes contributes for initiation and progression of microvascular and macrovascular complications. Shortened activated partial thromboplastin time (aPTT) values may reflect hypercoaguable state, which is associated with increased thrombotic risk and adverse cardiovascular events. Increased level of fibrinogen is common in type II diabetes. The present study was conducted to study the aPTT and fibrinogen levels in diabetics in a tertiary care Teaching Hospital of Nepal.

Methods

Observational study was performed at out-patients visiting Pathology Department at Tribhuvan University Teaching Hospital from August 5 to September 7, 2012. Research protocol was approved by Institutional Review Board at Tribhuvan University Institute of Medicine. Altogether 90 people who came to the hospital during study period and who met inclusion criteria were selected, out of which 72 were diabetics and 18 were normal controls. Diabetic cases were identified via verbal interview with patients themselves and review of laboratory findings and diagnosis performed by their physicians. Diabetics with a diabetic history of more than one year and stabilized with antidiabetic medicines such as insulin, metformin, glibenclamide, and gliclazide and diabetics with controlled diabetes as revealed by HbA_1c in the range 6.2-7% were taken for the study purpose. Data were analyzed with chi square test and Fischer’s exact test (when each cell frequency was less than 5) using Statistical Package for Social Sciences 17.

Results

Maximum (53; 73.6%) diabetics and all non-diabetics had aPTT in the range 26–40 seconds. Maximum (51; 70.8%) patients had fibrinogen beyond 351 whereas all non-diabetics had fibrinogen in the range 151–350. Mean aPTT values of the diabetic patients and non-diabetic persons were 29.88 ± 4.89 seconds and 32.44 ± 2.25 seconds respectively. Mean fibrinogen values of the diabetic patients and non-diabetic persons were 388.57 ± 60.90 mg/dL and 320.89 ± 10.20 mg/dL respectively. Test data identified in results were statistically significant for aPTT (p value 0.000) and fibrinogen (p value 0.000) between the diabetics and non-diabetics.

Conclusions

Diabetics have an increased level of fibrinogen and relatively shortened aPTT as compared to the non-diabetic patients.

ADAMTS13 predicts renal and cardiovascular events in type 2 diabetic patients and response to therapy

In patients with diabetes, impaired ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13) proteolysis of highly thrombogenic von Willebrand factor (VWF) multimers may accelerate renal and cardiovascular complications. Restoring physiological VWF handling might contribute to ACE inhibitors' (ACEi) reno- and cardioprotective effects. To assess how Pro618Ala ADAMTS13 variants and related proteolytic activity interact with ACEi therapy in predicting renal and cardiovascular complications, we genotyped 1,163 normoalbuminuric type 2 diabetic patients from BErgamo NEphrologic DIabetes Complications Trial (BENEDICT). Interaction between Pro618Ala and ACEi was significant in predicting both renal and combined renal and cardiovascular events. The risk for renal or combined events versus reference Ala carriers on ACEi progressively increased from Pro/Pro homozygotes on ACEi (hazard ratio 2.80 [95% CI 0.849-9.216] and 1.58 [0.737-3.379], respectively) to Pro/Pro homozygotes on non-ACEi (4.77 [1.484-15.357] and 1.99 [0.944-4.187]) to Ala carriers on non-ACEi (8.50 [2.416-29.962] and 4.00 [1.739-9.207]). In a substudy, serum ADAMTS13 activity was significantly lower in Ala carriers than in Pro/Pro homozygotes and in case subjects with renal, cardiovascular, or combined events than in diabetic control subjects without events. ADAMTS13 activity significantly and negatively correlated with all outcomes. In patients with diabetes, ADAMTS13 618Ala variant associated with less proteolytic activity, higher risk of chronic complications, and better response to ACEi therapy. Screening for Pro618Ala polymorphism may help identify patients with diabetes at highest risk who may benefit the most from early reno- and cardioprotective therapy.

Diabetes Mellitus, Admission Glucose, and Outcomes After Stroke Thrombolysis

Background and Purpose—

The potential detrimental effect of diabetes mellitus and admission glucose level (AGL) on outcomes after stroke thrombolysis is unclear. We evaluated outcomes of patients treated by intravenous and/or intra-arterial therapy, according to diabetes mellitus and AGL.

Methods—

We analyzed data from a patient registry (n=704) and conducted a systematic review of previous observational studies. The primary study outcome was the percentage of patients who achieved a favorable outcome (modified Rankin score ≤2 at 3 months).

Results—

We identified 54 previous reports that evaluated the effect of diabetes mellitus or AGL on outcomes after thrombolysis. In an unadjusted meta-analysis that included our registry data and previous available observational data, diabetes mellitus was associated with less favorable outcome (odds ratio [OR], 0.76; 95% confidence interval [CI], 0.73–0.79) and more symptomatic intracranial hemorrhage (OR, 1.38; 95% CI, 1.21–1.56). However, in multivariable analysis, diabetes mellitus remained associated with less favorable outcome (OR, 0.77; 95% CI, 0.69–0.87) but not with symptomatic intracranial hemorrhage (OR, 1.11; 95% CI, 0.83–1.48). In unadjusted and in adjusted meta-analysis, higher AGL was associated with less favorable outcome and more symptomatic intracranial hemorrhage; the adjusted OR (95% CI) per 1 mmol/L increase in AGL was 0.92 (0.90–0.94) for favorable outcome, and 1.09 (1.04–1.14) for symptomatic intracranial hemorrhage.

Conclusions—

These results confirm that AGL and history of diabetes mellitus are associated with poor clinical outcome after thrombolysis. AGL may be a surrogate marker of brain infarction severity rather than a causal factor. However, randomized controlled evidences are needed to address the significance of a tight glucose control during thrombolysis on clinical outcome.

Diabetes and vascular disease: pathophysiology, clinical consequences, and medical therapy: part I

Hyperglycemia and insulin resistance are key players in the development of atherosclerosis and its complications. A large body of evidence suggest that metabolic abnormalities cause overproduction of reactive oxygen species (ROS). In turn, ROS, via endothelial dysfunction and inflammation, play a major role in precipitating diabetic vascular disease. A better understanding of ROS-generating pathways may provide the basis to develop novel therapeutic strategies against vascular complications in this setting. Part I of this review will focus on the most current advances in the pathophysiological mechanisms of vascular disease: (i) emerging role of endothelium in obesity-induced insulin resistance; (ii) hyperglycemia-dependent microRNAs deregulation and impairment of vascular repair capacities; (iii) alterations of coagulation, platelet reactivity, and microparticle release; (iv) epigenetic-driven transcription of ROS-generating and proinflammatory genes. Taken together these novel insights point to the development of mechanism-based therapeutic strategies as a promising option to prevent cardiovascular complications in diabetes.

Dysfunction of annexin A2 contributes to hyperglycaemia-induced loss of human endothelial cell surface fibrinolytic activity

Hyperglycaemia impairs fibrinolytic activity on the surface of endothelial cells, but the underlying mechanisms are not fully understood. In this study, we tested the hypothesis that hyperglycaemia causes dysfunction of the endothelial membrane protein annexin A2, thereby leading to an overall reduction of fibrinolytic activity. Hyperglycaemia for 7 days significantly reduced cell surface fibrinolytic activity in human brain microvascular endothelial cells (HBMEC). Hyperglycaemia also decreased tissue type plasminogen activator (t-PA), plasminogen, and annexin A2 mRNA and protein expression, while increasing plasminogen activator inhibitor-1 (PAI-1). No changes in p11 mRNA or protein expression were detected. Hyperglycaemia significantly increased AGE-modified forms of total cellular and membrane annexin A2. The hyperglycemia-associated reduction in fibrinolytic activity was fully restored upon incubation with recombinant annexin A2 (rA2), but not AGE-modified annexin A2 or exogenous t-PA. Hyperglycaemia decreased t-PA, upregulated PAI-1 and induced AGE-related disruption of annexin A2 function, all of which contributed to the overall reduction in endothelial cell surface fibrinolytic activity. Further investigations to elucidate the underlying molecular mechanisms and pathophysiological implications of A2 derivatisation might ultimately lead to a better understanding of mechanisms of impaired vascular fibrinolysis, and to development of new interventional strategies for the thrombotic vascular complications in diabetes.

Platelet function profiles in patients with diabetes mellitus

Patients with diabetes mellitus (DM) are at high risk for several cardiovascular disorders such as coronary heart disease, stroke, peripheral arterial disease, and congestive heart failure. DM has reached epidemic proportions and its strong association with coronary artery disease is responsible for increased cardiovascular morbidity and mortality. DM patients are characterized by platelet hyperreactivity, which contribute to the enhanced atherothrombotic risk of these subjects. Several mechanisms are involved in the hyperreactive platelet phenotype characterizing DM patients. Furthermore, a large proportion of DM patients show inadequate response to standard antiplatelet treatments and high rate of adverse recurrent cardiovascular events despite compliance with standard antiplatelet treatment regimens. Therefore, new antiplatelet treatment regimens are warranted in DM patients to reduce their atherothrombotic risk. The present manuscript provides an overview on the current status of knowledge on platelet function profiles in patients with DM and therapeutic considerations.

Hyperglycemia increases susceptibility to ischemic necrosis

Diabetic patients are at risk for spontaneous foot ulcers, chronic wounds, infections, and tissue necrosis. Current theories suggest that the development and progression of diabetic foot ulcers are mainly caused by arteriosclerosis and peripheral neuropathy. Tissue necrosis plays a primordial role in the progression of diabetic foot ulcers but the underlying mechanisms are poorly understood. The aim of the present study was to investigate the effects of hyperglycemia per se on the susceptibility of ischemic tissue to necrosis, using a critical ischemic hind limb animal model. We inflicted the same degree of ischemia in both euglycemic and streptozotocin-induced hyperglycemic rats by resecting the external iliac, the femoral, and the saphenous arteries. Postoperative laser Doppler flowmetry of the ischemic feet showed the same degree of reduction in skin perfusion in both hyperglycemic and euglycemic animals. Nevertheless, we found a significantly higher rate of limb necrosis in hyperglycemic rats compared to euglycemic rats (71% versus 29%, resp.). In this study, we revealed that hyperglycemia per se increases the susceptibility to limb necrosis in ischemic conditions. Our results may help to better understand the physiopathology of progressive diabetic wounds and underline the importance of strict glycemic control in patients with critical limb ischemia.

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

Background

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

Methods

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

Results

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

Conclusions

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

Endothelial barrier dysfunction in diabetic conduit arteries: a novel method to quantify filtration

The endothelial barrier plays an important role in atherosclerosis, hyperglycemia, and hypercholesterolemia. In the present study, an accurate, reproducible, and user-friendly method was used to further understand endothelial barrier function of conduit arteries. An isovolumic method was used to measure the hydraulic conductivity (L(p)) of the intact vessel wall and medial-adventitial layer. Normal arterial segments with diameters from 0.2 to 5.5 mm were used to validate the method, and femoral arteries of diabetic rats were studied as an example of pathological specimens. Various arterial segments confirmed that the volume flux of water per unit surface area was linearly related to intraluminal pressure, as confirmed in microvessels. L(p) of the intact wall varied from 3.5 to 22.1 × 10(-7) cm·s(-1)·cmH(2)O(-1) over the pressure range of 7-180 mmHg. Over the same pressure range, L(p) of the endothelial barrier changed from 4.4 to 25.1 × 10(-7) cm·s(-1)·cmH(2)O(-1). During perfusion with albumin-free solution, L(p) of rat femoral arteries increased from 6.1 to 13.2 × 10(-7) cm·s(-1)·cmH(2)O(-1) over the pressure range of 10-180 mmHg. Hyperglycemia increased L(p) of the femoral artery in diabetic rats from 2.9 to 5.5 × 10(-7) cm·s(-1)·cmH(2)O(-1) over the pressure range of 20-135 mmHg. In conclusion, the L(p) of a conduit artery can be accurately and reproducibly measured using a novel isovolumic method, which in diabetic rats is hyperpermeable. This is likely due to disruption of the endothelial glycocalyx.

Glucose disturbances in non-diabetic patients receiving acute treatment with methylprednisolone pulses

OBJECTIVE

Methylprednisolone pulses are used in a variety of disease conditions, both for acute and chronic therapy. Although well tolerated, they increase glucose levels in both non-diabetic and diabetic patients. They may also be considered a significant risk for acute metabolic alterations. The purpose of this report is to determine the metabolic changes in blood glucose levels in non-diabetic patients receiving methylprednisolone pulses and identify the presence of predictive factors for its development.

METHODS

Observational, prospective study in 50 non-diabetic patients receiving 1 g intravenous methylprednisolone pulses for three consecutive days as an indication for diverse autoimmune disorders. Demographic, anthropometric, and metabolic variables were analyzed, and glucose, insulin and C-peptide levels after each steroid pulse were identified. Different variables and the magnitude of hyperglycemia were analyzed using Pearson's correlation.

RESULTS

50 patients were included, predominantly women (66%, n = 33). The average age was 41 ± 14 years with a BMI of 26 ± 3 kg/m². Baseline glucose was 83 ± 10 mg/dL. After each steroid pulse, glucose increased to 140 ± 28, 160 ± 38 and 183 ± 44, respectively (p < 0.001). C-peptide and insulin concentrations increased significantly (p < 0.001). The prevalence of fasting hyperglycemia after each pulse was 68%, 94% and 98%, respectively. We found no correlation between the magnitude of hyperglycemia and the studied variables.

CONCLUSION

Methylprednisolone pulses produced significant increases in fasting glucose in most patients without diabetes. Further studies are needed to define its role in long-term consequences.

Diabetes, hyperglycaemia, and acute ischaemic stroke

Diabetes and ischaemic stroke often arise together. People with diabetes have more than double the risk of ischaemic stroke after correction for other risk factors, relative to individuals without diabetes. Multifactorial treatment of risk factors for stroke-in particular, lifestyle factors, hypertension, and dyslipidaemia-will prevent a substantial number of these disabling strokes. Hyperglycaemia occurs in 30-40% of patients with acute ischaemic stroke, also in individuals without a known history of diabetes. Admission hyperglycaemia is associated with poor functional outcome, possibly through aggravation of ischaemic damage by disturbing recanalisation and increasing reperfusion injury. Uncertainty surrounds the question of whether glucose-lowering treatment for early stroke can improve clinical outcome. Achievement of normoglycaemia in the early stage of stroke can be difficult, and the possibility of hypoglycaemia remains a concern. Phase 3 studies of glucose-lowering therapy in acute ischaemic stroke are underway.

A high red blood cell distribution width predicts failure of arteriovenous fistula

In hemodialysis patients, a native arteriovenous fistula (AVF) is the preferred form of permanent vascular access. Despite recent improvements, vascular access dysfunction remains an important cause of morbidity in these patients. In this prospective observational cohort study, we evaluated potential risk factors for native AVF dysfunction. We included 68 patients with chronic renal disease stage 5 eligible for AVF construction at the Department of General and Vascular Surgery, Central Clinical Hospital Ministry of Internal Affairs, Warsaw, Poland. Patient characteristics and biochemical parameters associated with increased risk for AVF failure were identified using Cox proportional hazards models. Vessel biopsies were analyzed for inflammatory cells and potential associations with biochemical parameters. In multivariable analysis, independent predictors of AVF dysfunction were the number of white blood cells (hazard ratio [HR] 1.67; 95% confidence interval [CI] 1.24 to 2.25; p<0.001), monocyte number (HR 0.02; 95% CI 0.00 to 0.21; p = 0.001), and red blood cell distribution width (RDW) (HR 1.44; 95% CI 1.17 to 1.78; p<0.001). RDW was the only significant factor in receiver operating characteristic curve analysis (area under the curve 0.644; CI 0.51 to 0.76; p = 0.046). RDW>16.2% was associated with a significantly reduced AVF patency frequency 24 months after surgery. Immunohistochemical analysis revealed CD45-positive cells in the artery/vein of 39% of patients and CD68-positive cells in 37%. Patients with CD68-positive cells in the vessels had significantly higher white blood cell count. We conclude that RDW, a readily available laboratory value, is a novel prognostic marker for AVF failure. Further studies are warranted to establish the mechanistic link between high RDW and AVF failure.

Exogenous activated protein C inhibits the progression of diabetic nephropathy

BACKGROUND

Activated protein C (APC) can regulate immune and inflammatory responses and apoptosis. Protein C transgenic mice develop less diabetic nephropathy but whether exogenous administration of APC suppresses established diabetic nephropathy is unknown.

OBJECTIVES

We investigated the therapeutic potential of APC in mice with streptozotocin-induced diabetic nephropathy.

METHODS

Diabetes was induced in unilaterally nephrectomized C57/Bl6 mice using intraperitoneal (i.p.) injection of streptozotocin. Four weeks later, the mice were treated with i.p. exogenous APC every other day for 1 month.

RESULTS

APC-treated mice had a significantly improved blood nitrogen urea-to-creatinine ratio, urine total protein to creatinine ratio and proteinuria, and had significantly less renal fibrosis as measured by the levels of collagen and hydroxyproline. The renal tissue concentration of monocyte chemoattractant protein-1 (MCP-1), vascular endothelial growth factor (VEGF) and the RNA expression of platelet-derived growth factor (PDGF), transforming growth factor-β1 and connective tissue growth factor (CTGF) were significantly lower in APC-treated mice than in untreated animals. The percentage of apoptotic cells was reduced and the expression of podocin, nephrin and WT-1 in the glomeruli was significantly improved in mice treated with APC compared with untreated mice. The levels of coagulation markers were not affected by APC treatment.

CONCLUSION

Exogenous APC improves renal function and mitigates pathological changes in mice with diabetic nephropathy by suppressing the expression of fibrogenic cytokines, growth factors and apoptosis, suggesting its potential usefulness for the therapy of this disease.

Anticoagulatory and antiinflammatory effects of astaxanthin in diabetic rats

Astaxanthin at 0.01 or 0.05% of the diet was supplied to diabetic rats for 12 wk. Astaxanthin intake significantly increased its deposit in plasma, and retained glutathione content, reduced the production of reactive oxygen species, interleukin-6, tumor necrosis factor-α, and monocyte chemoattractant protein-1 in blood and kidney of diabetic rats (P < 0.05). Astaxanthin treatments also significantly decreased plasma levels of C-reactive protein and von Willebrand factor in diabetic rats (P < 0.05). Astaxanthin intake at 0.05% significantly diminished plasminogen activator inhibitor-1 and factor VII activities, enhanced antithrombin-III and protein C activities in circulation (P < 0.05). These results support that astaxanthin could attenuate diabetes associated coagulatory, oxidative, and inflammatory stress.

Elevated admission glucose and mortality in patients with acute pulmonary embolism

OBJECTIVE

Although associated with adverse outcomes in other cardiopulmonary conditions, the prognostic value of elevated glucose in patients with acute pulmonary embolism (PE) is unknown. We sought to examine the association between glucose levels and mortality and hospital readmission rates for patients with PE.

RESEARCH DESIGN AND METHODS

We evaluated 13,621 patient discharges with a primary diagnosis of PE from 185 acute care hospitals in Pennsylvania (from January 2000 to November 2002). Admission glucose levels were analyzed as a categorical variable (≤110, >110-140, >140-170, >170-240, and >240 mg/dL). The outcomes were 30-day all-cause mortality and hospital readmission. We used random-intercept logistic regression to assess the independent association between admission glucose levels and mortality and hospital readmission, adjusting for patient (age, sex, race, insurance, comorbid conditions, severity of illness, laboratory parameters, and thrombolysis) and hospital (region, size, and teaching status) factors.

RESULTS

Elevated glucose (>110 mg/dL) was present in 8,666 (63.6%) patients. Patients with a glucose level ≤110, >110-140, >140-170, >170-240, and >240 mg/dL had a 30-day mortality of 5.6, 8.4, 12.0, 15.6, and 18.3%, respectively (P < 0.001). Compared with patients with a glucose level ≤110 mg/dL, the adjusted odds of dying were greater for patients with a glucose level >110-140 (odds ratio 1.19 [95% CI 1.00-1.42]), >140-170 (1.44 [1.17-1.77]), >170-240 (1.54 [1.26-1.90]), and >240 mg/dL (1.60 [1.26-2.03]), with no difference in the odds of hospital readmission.

CONCLUSIONS

In patients with acute PE, elevated admission glucose is common and independently associated with short-term mortality.

Diabetes mellitus and thrombosis

Atherothrombosis is the leading cause of morbidity and mortality in patients with diabetes mellitus. Several mechanisms contribute to the diabetic prothrombotic state, including endothelial dysfunction, coagulative activation and platelet hyper-reactivity. In particular, diabetic platelets are characterised by dysregulation of several signaling pathways leading to enhanced adhesion, activation and aggregation. These alterations result from the interaction among hyperglycemia, insulin resistance, inflammation and oxidative stress. This review will provide an overview of the current status of knowledge on mechanisms of accelerated atherothrombosis in patients with diabetes mellitus.

Special considerations for the diabetic patient in the ICU; targets for treatment and risks of hypoglycaemia

Due to the diabetes pandemic the number of diabetic patients admitted to the intensive care unit (ICU) increases. Diabetic patients admitted to the ICU are more vulnerable for developing complications as compared to non-diabetic patients, but this does not directly translate into higher mortality rates. However, mortality might differ per admission diagnosis. Hyperglycaemia is common in diabetic as well as non-diabetic critically ill patients, but probably chronic hyperglycaemia is pathophysiologically different from acute hyperglycaemia. As opposed to non-diabetic patients, there is discussion about the association between hyperglycaemia and mortality in diabetic patients. They do not seem to benefit from strict glycaemic control and also glucose variability appears less harmful, although clinical trials in diabetic populations have not been performed yet. Diabetes is a risk factor for hypoglycaemia and evidence suggests that even near-normal glucose levels are associated with worse outcome. Taking this together, it is suggested to strive for moderate targets when treating hyperglycaemia in critically ill diabetic patients.

Elevated levels of PAI-1 activity and t-PA antigen are associated with newly diagnosed abnormal glucose regulation in patients with ST-elevation myocardial infarction

BACKGROUND

Both Type 2 diabetes and cardiovascular disease have been associated with enhanced coagulation and suppressed fibrinolysis.

OBJECTIVES

To investigate a possible relationship between selected hemostatic variables and abnormal glucose regulation (AGR) in patients with acute ST-elevation myocardial infarction (STEMI) without known diabetes and to study changes in selected hemostatic variables from baseline to follow-up in STEMI patients with or without AGR.

METHODS

Plasminogen activator inhibitor-1 (PAI-1) activity, tissue plasminogen activator (t-PA) antigen, prothrombin fragment 1+2 (F(1+2)) and von Willebrand factor (vWF) were measured in fasting blood samples from 199 STEMI patients 16.5 h (median time) after admission and 3 months later. All patients were classified into normal glucose regulation (NGR) or AGR based on an oral glucose tolerance test at follow-up, according to the WHO criteria.

RESULTS

High PAI-1 activity (≥ 75th percentile) measured in-hospital was associated with AGR (n = 49) with an adjusted odds ratio of 2.2 (95% confidence interval, 1.1, 4.4). In addition, high levels of t-PA antigen (≥ 75th percentile) were associated with AGR (adjusted odds ratio, 3.5; 95% confidence inteval, 1.5, 8.2), but only in men. Changes in the levels of F(1+2) were significantly more pronounced in patients with AGR compared with NGR (adjusted P = 0.04).

CONCLUSION

Elevated levels of PAI-1 activity and t-PA antigen measured in-hospital in STEMI patients were associated with AGR classified at 3-month follow-up. Additionally, changes in the levels of F(1+2) were more pronounced in patients with AGR compared with NGR. The data suggest an enhanced prothrombotic state after an acute STEMI in patients with AGR without known diabetes.

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.

Platelet abnormalities in diabetes mellitus

Patients with diabetes mellitus (DM) have accelerated atherosclerosis, which is the main underlying factor contributing to the high risk of atherothrombotic events in these patients. Atherothrombotic complications are the leading cause of morbidity and mortality in patients with DM. Among factors contributing to the prothrombotic condition which characterise patients with DM, platelet hyperreactivity plays a pivotal role. Platelets of DM patients are characterised by dysregulation of several signalling pathways leading to intensified adhesion, activation and aggregation. Multiple mechanisms are involved in platelet dysfunction of patients with DM, which can be categorised as follows: a) hyperglycaemia, b) insulin deficiency and resistance, c) associated metabolic conditions, and d) other cellular abnormalities.The present manuscript aims to provide an overview on the current status of knowledge on platelet abnormalities that characterise patients with DM.

A clinical cardiology perspective of thrombophilias

Thrombophilias, an inherited and/or acquired predisposition to vascular thrombosis beyond hemostatic needs are common in cardiovascular medicine and include systemic disorders such as coronary atherosclerosis, atrial fibrillation, exogenous obesity, metabolic syndrome, collagen vascular disease, human immunodeficiency virus, blood replacement therapy and several commonly used medications. A contemporary approach to patients with suspected thrombophilias, in addition to a very selective investigation for gain-of-function and loss-of-function gene mutations affecting thromboresistance, must consider prevalent diseases and management decisions encountered regularly by cardiologists in clinical practice. An appropriate recognition of common disease states as thrombophilias will also stimulate platforms for much needed scientific investigation.