Platelet activation in type 2 diabetes mellitus

The Heart in Diabetic Ketoacidosis: A Narrative Review Focusing on the Acute Cardiac Effects and Electrocardiographic Abnormalities

Diabetic ketoacidosis (DKA) is a serious complication of diabetes mellitus. Hyperglycemia, acidosis, and electrolyte imbalances can directly affect the heart by inducing toxicity, impairing myocardial blood flow, autonomic dysfunction, and altering activation and conduction of electrical impulses throughout the heart, increasing the risk of arrhythmias and ischemia. The electrocardiogram is useful in monitoring patients during and after an episode of DKA, as it allows the detection of arrhythmias and guides metabolic correction. Unfortunately, reports on electrocardiographic abnormalities in patients with DKA are lacking. We found two electrocardiographic patterns that are frequently reported in the literature: a pseudo-myocardial infarction and a Brugada Phenocopy. Both are associated with DKA metabolic anomalies and they resolve after treatment. Because of their clinical relevance and the challenge they represent for clinicians, we analyzed the clinical characteristics of these patients and the mechanisms involved in these electrocardiographic findings.

Comprehensive platelet phenotyping supports the role of platelets in the pathogenesis of acute venous thromboembolism - results from clinical observation studies

Background

The pathogenesis of arterial and venous thrombosis is in large part interlaced. How much platelet phenotype relates to acute venous thromboembolism (VTE) independent of the underlying cardiovascular profile is presently poorly investigated.

Methods

Platelet count and mean platelet volume (MPV), platelet aggregation in whole blood and platelet rich plasma (PRP), platelet-dependent thrombin generation (TG) and platelet surface activation markers were measured under standardized conditions. Machine learning was applied to identify the most relevant characteristics associated with VTE from a large array (N = 58) of clinical and platelet-related variables.

Findings

VTE cases (N = 159) presented with lower platelet count and MPV vs controls (N = 140). Whole blood aggregation showed shorter collagen/Epinephrine closure times in cases, particularly within acetylsalicylic acid (ASA) users. Within ASA users, higher PRP aggregation after adenosine diphosphate (ADP), epinephrine, collagen and arachidonic acid was observed in cases vs controls. Within non-ASA and/or subjects on anticoagulants, cases presented with lower aggregation after ADP and collagen vs controls. Lower platelet-dependent TG, higher CD63 on resting and lower PAC-1 expression after collagen/ADP in-vitro stimulated platelets further characterized VTE cases vs controls, independent of therapy. Lasso regression analysis identified 26 variables associated with VTE of which 69% were platelet-related.

Interpretation

Comprehensive phenotyping of platelet function identified a large proportion of low responders to ASA in VTE cases. Lower platelet-dependent TG and lower platelet reactivity after ex-vivo stimulation characterized the “platelet exhausted syndrome” in cases. Finally, from a large array of covariates including clinical risk factors, platelet biomarkers comprised 69% of all selected variables differentiating VTE cases vs controls.

Funding

German Federal Ministry of Education and Research, CTH-Mainz and Bayer AG.

Mean Platelet Volume as a Marker of Vasculogenic Erectile Dysfunction and Future Cardiovascular Risk

Cardiovascular diseases are the main cause of mortality in the Western population, so the attempt to find a marker capable of predicting their early onset is not surprising. It is known that arteriogenic erectile dysfunction (ED) precedes the onset of a major coronary event by several years. However, a marker that is able to early identify those patients who should undergo further diagnostic investigations is, to date, missing. Recent research on this topic has focused on the role of the mean platelet volume (MPV), a marker of platelet activity that is high in most vascular diseases, such as coronary artery disease (CAD), stroke, peripheral artery disease (PAD), and ED. The basic pathophysiological mechanism of all these clinical conditions is atherosclerosis. Platelets play a central role in amplifying this process both indirectly by stimulating endothelial cells to produce inflammatory cytokines and chemokines, and directly through the expression of membrane receptors and the release of molecules that contribute to the formation of atherosclerotic plaque. The objective of this review is to critically analyze the evidence on the role of MPV in predicting the diagnosis and severity of vasculogenic ED and the possibility of using this simple marker as a first step to start a diagnostic process aimed at assessing the cardiovascular risk in these patients.

Association between High On-Aspirin Platelet Reactivity and Reduced Superoxide Dismutase Activity in Patients Affected by Type 2 Diabetes Mellitus or Primary Hypercholesterolemia

Platelet hyperactivation is involved in the established prothrombotic condition of metabolic diseases such as Type 2 Diabetes Mellitus (T2DM) and familial hypercholesterolemia (HC), justifying the therapy with aspirin, a suppressor of thromboxane synthesis through the irreversible inhibition of cyclooxygenase-1 (COX-1), to prevent cardiovascular diseases. However, some patients on aspirin show a higher than expected platelet reactivity due, at least in part, to a pro-oxidant milieu. The aim of this study was to investigate platelet reactivity in T2DM (n = 103) or HC (n = 61) patients (aspirin, 100 mg/day) and its correlation with biomarkers of redox function including the superoxide anion scavenger superoxide dismutase (SOD) and the in vivo marker of oxidative stress urinary 8-iso-prostaglandin F_2α. As results, in T2DM and HC subjects the prevalence of high on-aspirin platelet reactivity was comparable when both non-COX-1-dependent and COX-1-dependent assays were performed, and platelet reactivity is associated with a lower SOD activity that in a stepwise linear regression appears as the only predictor of platelet reactivity. To conclude, in T2DM and HC, similarly, the impairment of redox equilibrium associated with a decrease of SOD activity could contribute to a suboptimal response to aspirin.

Platelet Inhibition with Ticagrelor versus Clopidogrel in Diabetic Patients after Percutaneous Coronary Intervention for Chronic Coronary Syndromes

BACKGROUND

 Clopidogrel is currently the only P2Y₁₂ inhibitor with class I recommendation in patients after percutaneous coronary intervention (PCI) for chronic coronary syndromes (CCS). Diabetic patients have reduced therapeutic response to clopidogrel.

PURPOSE

 This study assessed the antiplatelet effect of ticagrelor versus clopidogrel in diabetic patients after recent PCI for CCS.

METHODS

 Eligible patients were randomly assigned to receive ticagrelor 90 mg twice daily or clopidogrel 75 mg once daily, in addition to aspirin 100 mg once daily for 15 days. P2Y₁₂ reaction unit (PRU) and percent inhibition were measured by VerifyNow P2Y₁₂ assay. High on-treatment platelet reactivity (HOPR) was defined as PRU > 208. Bleeding was assessed by the Platelet Inhibition and Patient Outcomes criteria. Cardiac ischemic events were evaluated as adverse events.

RESULTS

 The baseline characteristics of the patients (n = 39) were well balanced between the two groups. Both before and 2 to 4 hours after the final study dose on day 15, PRU was lower (41.3 ± 35.8 vs. 192.6 ± 49.5, p < 0.001; 36.6 ± 25.8 vs. 187.6 ± 70.9, p < 0.001), percent inhibition was higher (83.0% [70.5%, 96.0%] vs. 16.0% [0%, 25.0%], p < 0.001; 85.0% [76.0%, 96.5%] vs. 25.0% [0%, 39.0%], p < 0.001), and HOPR occurred less frequently (0% [0/20] vs. 26.3% [5/19], p = 0.020; 0% [0/20] vs. 31.6% [6/19], p = 0.008) in the ticagrelor group (n = 20) compared with the clopidogrel group (n = 19). No major or minor bleeding, or serious adverse events occurred in both groups.

CONCLUSION

 Ticagrelor achieved greater peak and trough platelet inhibition than did clopidogrel in diabetic patients after recent PCI for CCS, which suggests the potential use of ticagrelor in this clinical setting.

The Timing of Symptomatic Pulmonary Embolism in Patients With Nonwarfarin Anticoagulants Following Elective Primary Total Joint Arthroplasty

BACKGROUND

The purpose of this study is to investigate the incidence and timing of postoperative, symptomatic pulmonary embolism (PE) in patients receiving nonwarfarin treatment following primary total joint arthroplasty (TJA), to clarify the appropriate duration of postoperative VTE prophylaxis.

METHODS

We retrospectively reviewed the medical records of 11,148 patients who underwent primary TJA, including total knee arthroplasty and total hip arthroplasty at our institution between January 2012 and March 2019. The median postoperative day of diagnosis of symptomatic PE and the interquartile range for day of diagnosis were determined. Multivariate Cox proportional hazards modeling was used to test the difference of timing for PE based on demographics and comorbidities.

RESULTS

The overall 90-day rate of symptomatic PE was 0.71%. The median day of diagnosis for symptomatic PE was 3 days postoperatively (interquartile range, 2-7 days). Factors showed statistical significance on multivariate analysis in association with earlier timing of PE occurrence in patients with atrial fibrillation, diabetes mellitus, coronary heart disease, and history of stroke.

CONCLUSION

The vast majority of symptomatic PE occurs in the early postoperative period after TJA, and atrial fibrillation, diabetes mellitus, coronary heart disease, and history of stroke were independent factors affecting the timing of symptomatic PE.

Diabetes and Hyperglycemia Affect Platelet GPIIIa Expression. Effects on Adhesion Potential of Blood Platelets from Diabetic Patients under In Vitro Flow Conditions

Blood platelets play a crucial role in the early stages of atherosclerosis development. The process is believed to require firm adhesion of platelets to atherosclerosis-prone sites of the artery. However, little evidence exists regarding whether the blood platelets of individuals with pathological conditions associated with atherosclerosis have higher potential for adhesion. This process is to a large extent dependent on receptors present on the platelet membrane. Therefore, the aim of the presented study was to determine whether blood platelets from diabetic patients have higher capacity of adhesion under flow conditions and how diabetes affects one of the crucial platelet receptors involved in the process of adhesion-GPIIIa. The study compares the ability of platelets from non-diabetic and diabetic humans to interact with fibrinogen and von Willebrand factor, two proteins found in abundance on an inflamed endothelium, under flow conditions. The activation and reactivity of the blood platelets were also characterized by flow cytometry. Platelets from diabetic patients did not demonstrate enhanced adhesion to either studied protein, although they presented increased basal activation and responsiveness towards low concentrations of agonists. Platelets from diabetic patients were characterized by lower expression of GPIIIa, most likely due to an enhanced formation of platelet-derived microparticles PMPs, as supported by the observation of elevated concentration of this integrin and of GPIIIa-positive PMPs in plasma. We conclude that altered functionality of blood platelets in diabetes does not increase their adhesive potential. Increased glycation and decrease in the amount of GPIIIa on platelets may be partially responsible for this effect. Therefore, higher frequency of interactions of platelets with the endothelium, which is observed in animal models of diabetes, is caused by other factors. A primary cause may be a dysfunctional vascular wall.

Effects of Nigella sativa on endothelial dysfunction in diabetes mellitus: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Endothelial dysfunction is involved in lesion generation by the promotion of both early and late mechanism(s) of atherosclerosis such as adhesion molecules up-regulation, increased chemokine secretion and leukocyte adherence, increased cell permeability, enhanced low-density lipoprotein oxidation, cytokine elaboration, platelet activation and vascular smooth muscle cell migration, and proliferation. Nigella sativa is from the Ranunculaceae family which is used in some countries for various medicinal purposes. Nigella sativa seed has been widely used in traditional medicine for the treatment of diabetes.

AIM OF THE REVIEW

This review article summarized the therapeutic effects of Nigella sativa on endothelial dysfunction.

METHODS

Databases such as PubMed, Web of Science, Google Scholar, Scopus, and Iran Medex were considered. The search terms were " Nigella sativa " or "endothelium" and " Diabetes"," endothelial dysfunction ", " Thymoquinone " and " anti-inflammatory effect ".

RESULTS

The current review shows that Nigella sativa and Thymoquinone have a protective effect on endothelial dysfunction induced by diabetes. This is done by several mechanisms such as reduction of inflammatory and apoptotic markers, improving hyperglycemia, hyperlipidemia and antioxidant function, inhibiting platelet aggregation, and regulating eNOS, VCAM-1 and LOX-1 genes expression that involve in the endothelial dysfunction. Thymoquinone also reduces expression and secretion of some cytokines such as MCP-1, interleukin-1β, TNF-α, NF-κB, and Cox-2 that result in anti-inflammation effect.

CONCLUSION

Thymoquinone, the main phenolic terpene found in Nigella sativa, has several important properties such as antidiabetic, anti-inflammatory, and antioxidant activity. Therefore, Nigella sativa can improve endothelial dysfunction.

[E-Selectin as a Marker of Endothelial Dysfunction in Patients with Coronary Artery Disease Including Those with Type 2 Diabetes Mellitus]

Aim To determine concentration of the endothelial dysfunction (ED) marker, serum E-selectine, in patients with ischemic heart disease (IHD) in combination with type 2 diabetes mellitus (DM) and without DM.Material and methods The study included 60 IHD patients; 31 of them also had type 2 DM. E-selectin was measured in blood of all patients. In addition, a comprehensive evaluation of the morpho-functional condition of large blood vessels and microvasculature (MV) was performed by laser finger plethysmography (LFP) and nailfold computed videocapillaroscopy (CVC).Results Concentration of E-selectin was increased in IHD patients with type 2 DM (35.2 [29.0; 47.35] ng / ml vs. 31.7 [20.85; 36.68] ng / ml for IHD patients; p=0.028). A significant (p=0.018 and 0.016, respectively) decrease in the phase shift was observed in IHD patients with type 2 DM ( - 4.4 [ - 8.7; - 2.45] ms) compared to IHD patients ( - 1.9 [ - 3.95; - 0.38] ms). The capillary density evaluated in the venous occlusion test was reduced in IHD patients with type 2 DM (67.70 [57.83; 80.69]) compared to IHD patients (80.80 [69.05; 99.08]).Conclusion The signs of ED observed in patients of both groups were more pronounced in IHD patients with type 2 DM.

Clinical Management of Stable Coronary Artery Disease in Patients With Type 2 Diabetes Mellitus: A Scientific Statement From the American Heart Association

Although cardiologists have long treated patients with coronary artery disease (CAD) and concomitant type 2 diabetes mellitus (T2DM), T2DM has traditionally been considered just a comorbidity that affected the development and progression of the disease. Over the past decade, a number of factors have shifted that have forced the cardiology community to reconsider the role of T2DM in CAD. First, in addition to being associated with increased cardiovascular risk, T2DM has the potential to affect a number of treatment choices for CAD. In this document, we discuss the role that T2DM has in the selection of testing for CAD, in medical management (both secondary prevention strategies and treatment of stable angina), and in the selection of revascularization strategy. Second, although glycemic control has been recommended as a part of comprehensive risk factor management in patients with CAD, there is mounting evidence that the mechanism by which glucose is managed can have a substantial impact on cardiovascular outcomes. In this document, we discuss the role of glycemic management (both in intensity of control and choice of medications) in cardiovascular outcomes. It is becoming clear that the cardiologist needs both to consider T2DM in cardiovascular treatment decisions and potentially to help guide the selection of glucose-lowering medications. Our statement provides a comprehensive summary of effective, patient-centered management of CAD in patients with T2DM, with emphasis on the emerging evidence. Given the increasing prevalence of T2DM and the accumulating evidence of the need to consider T2DM in treatment decisions, this knowledge will become ever more important to optimize our patients' cardiovascular outcomes.

A Pilot Study on the Effect of Anti-Thrombopoietin Antibody on Platelet Count in Patients with Type 2 Diabetes

Thrombopoietin (THPO) is a circulatory cytokine that plays an important role in platelet production. The presence of anti-THPO antibody relates to thrombocytopenia and is rarely seen in hematopoietic and autoimmune diseases. To date, there had been no reports that focused on the anti-THPO antibody in patients with type 2 diabetes mellitus (T2DM). To evaluate prevalence of the anti-THPO antibody in patients with T2DM and the relationship between anti-THPO antibody and platelet count, a cross-sectional study was performed on 82 patients with T2DM. The anti-THPO antibody was measured by ELISA using preserved sera and detected in 13 patients. The average platelet count was significantly lower in patients with the anti-THPO antibody than in those without the anti-THPO antibody. Multivariate linear regression analyses showed a significant relationship between the anti-THPO antibody and platelet count, after adjusting for other variables. To our best knowledge, this was the first report on the effect of the anti-THPO antibody on platelet count in patients with T2DM. Further investigation is needed to validate the prevalence and pathological significance of the anti-THPO antibody in patients with T2DM.

Platelet volume indices as predictive biomarkers for diabetic complications in Type 2 diabetic patients

BACKGROUND:

Platelet volume indices (PVI) such as mean platelet volume (MPV), platelet distribution width (PDW), and platelet-large cell ratio (P-LCR) are the indicators of increased platelet activity and can be considered as potential biomarkers for diabetic complications.

PURPOSE:

To study PVI in Type 2 diabetics with and without complications in comparison to nondiabetic patients.

MATERIALS AND METHODS:

A case–control study was conducted on 300 Type 2 diabetics and 200 nondiabetics. Detailed clinical history regarding duration, hypertension, and complications was taken. PVI was obtained using automated cell counter. Fasting blood glucose, hemoglobin A1c, lipid profile, creatinine were also obtained. Diabetics were further categorized into patients with complications and without complications. Statistical analysis was performed by Statistical Package for the Social Sciences Version 17 (Chicago, IL) Student's t-test and ANOVA test.

RESULTS:

Platelet count was significantly decreased in diabetics (P = 0.005). MPV was significantly increased in diabetic patients with complications as compared to diabetics without complications and nondiabetic group (P < 0.0001). PDW showed statistically significant difference between diabetics with and without complications and nondiabetics (P < 0.0001). However, no statistically significant difference was observed in platelet-large cell ratio (P-LCR) among all the three study groups. We found statistically significant correlation of MPV with diabetic retinopathy (P = 0.000), nephropathy (P = 0.005), and diabetic foot (P = 0.048). PDW was significantly increased in diabetic retinopathy (P = 0.035) and nephropathy (P = 0.007). P-LCR had no statistically significant correlation with diabetic complications.

CONCLUSION:

MPV and PDW are predictive biomarkers of diabetic vascular complications. They are more significant in microvascular complications than macrovascular complications.

Prognostic Value of Hyperglycemia on Admission on In-hospital Outcomes in Patients Presenting with ST-elevation Myocardial Infarction

Background

Type 2 diabetes mellitus (T2DM) is associated with acute coronary syndrome, and elevated blood glucose levels on hospital admission may influence outcomes in patients with ST-elevated myocardial infarction (STEMI). We conducted this study to determine the prognostic outcome of hyperglycemia at admission on in-hospital outcomes of STEMI patients with and without T2DM.

Methods

This prospective study was conducted from June 13, 2018, to October 12, 2019, and included patients older than 18 years diagnosed with STEMI. For our purposes, hyperglycemia was defined as blood glucose levels >140 mg/dl. Hypertension was considered as systolic blood pressure >140 mmHg or diastolic pressure > 90 mmHg. The predictive value of glycemia on admission for outcomes was assessed via patient mortality following thrombolysis or percutaneous coronary intervention (PCI).

Results

Our study included 256 patients (196 men, 76.5%; 60 women, 23.5%) with a mean age of 55 ± 11 years. A total of 92 patients (35.9%) were admitted with known T2DM diagnoses: 72 of them had hyperglycemia and 20 patients had euglycemia (p = 0.0001). Post-PCI mortality was six (18.8%) in the hyperglycemic group and one (2.2%) in the euglycemic group (p = 0.03). In-hospital mortality was higher in the hyperglycemic group (n = 12, 12.5%) compared to the euglycemic group (n = 6, 3.7%; p = 0.015). Significant risk factors of mortality for STEMI patients with hyperglycemia on admission were age 60 years or older (odds ratio [OR], 5.63 [1.54-20.58]; p = 0.007), heart failure on admission (OR, 6.84 [1.85-25.22)]; p = 0.003), T2DM (OR, 4.14 [0.50-33.96]; p = 0.05), and presenting with renal failure (OR, 6.78 [1.74-26.42]; p = 0.009).

Conclusion

Thrombolysis and PCI are effective and safe treatments in STEMI patients. Hyperglycemia has a great adverse impact on hospital outcomes in patients with or without T2DM. STEMI patients with hyperglycemia on hospital admission have higher mortality rates.

Elevated HbA1c is not associated with recurrent venous thromboembolism in the elderly, but with all-cause mortality- the SWEETCO 65+ study

The association of glycated hemoglobin (HbA1c) with venous thromboembolism (VTE) and death in the elderly is unknown. In the SWEETCO 65+ study we analyzed prospectively a Swiss Cohort of Elderly Patients with Venous Thromboembolism (SWITCO 65+). 888 patients were enrolled for the SWEETCO 65+ analysis. HbA1c was determined at baseline and divided into three categories (HbA1c < 5.7%, normal range; 5.7–6.49%, pre-diabetic range; and >6.5%, diabetic range). Median follow-up was 2.5 years. The primary endpoint was recurrent VTE. Secondary endpoints included all-cause mortality and major bleeds. The total prevalence of diabetes was 22.1%. The risk of recurrent VTE was similar in patients with HbA1c with pre-diabetes (adjusted subhazard ratio (aSHR) 1.07 [0.70 to 1.63]) and diabetes (aSHR 0.73 [0.39 to 1.37]) as compared to those with a HbA1c in the normal range. However, a HbA1c ≥ 6.5% (median IQ range 7.0 [6.70;7.60]) was significantly associated with a higher risk of all-cause mortality (adjusted hazard ratio [aHR] 1.83 [1.21 to 2.75]). In summary we found no association between HbA1c and major bleeding. Elevated HbA1c levels are not associated with recurrent VTE but with increased all-cause mortality in an elderly population with acute VTE.

Influence of Cardiometabolic Risk Factors on Platelet Function

Platelets are key players in the thrombotic processes. The alterations of platelet function due to the occurrence of metabolic disorders contribute to an increased trend to thrombus formation and arterial occlusion, thus playing a major role in the increased risk of atherothrombotic events in patients with cardiometabolic risk factors. Several lines of evidence strongly correlate metabolic disorders such as obesity, a classical condition of insulin resistance, dyslipidemia, and impaired glucose homeostasis with cardiovascular diseases. The presence of these clinical features together with hypertension and disturbed microhemorrheology are responsible for the prothrombotic tendency due, at least partially, to platelet hyperaggregability and hyperactivation. A number of clinical platelet markers are elevated in obese and type 2 diabetes (T2DM) patients, including the mean platelet volume, circulating levels of platelet microparticles, oxidation products, platelet-derived soluble P-selectin and CD40L, thus contributing to an intersection between obesity, inflammation, and thrombosis. In subjects with insulin resistance and T2DM some defects depend on a reduced sensitivity to mediators—such as nitric oxide and prostacyclin—playing a physiological role in the control of platelet aggregability. Furthermore, other alterations occur only in relation to hyperglycemia. In this review, the main cardiometabolic risk factors, all components of metabolic syndrome involved in the prothrombotic tendency, will be taken into account considering some of the mechanisms involved in the alterations of platelet function resulting in platelet hyperactivation.

Inhibition of pyruvate dehydrogenase complex activity by 3-bromopyruvate affects blood platelets responses in type 2 diabetes

BACKGROUND

Hyperactivation of blood platelets is an essential factor in the pathomechanism of diabetes-evoked angiopathies. The aim of this work was to investigate whether blood platelets hyperactivation resulting from type 2 diabetic hyperglycaemia-increased pyruvate dehydrogenase complex activity and excessive acetyl-CoA accumulation may be brought to the normal range by the enzyme inhibitors.

METHODS

Platelets were isolated from the blood of 9 type 2 diabetic patients and 10 healthy donors. Effects of 3-bromopyruvate and 3-nitropropionate on pyruvate dehydrogenase complex (PDHC) and succinate dehydrogenase activities, as well as levels of acetyl-CoA, ATP, thiobarbituric acid reactive species and aggregation were assessed in non-activated and thrombin-activated platelets.

RESULTS

In type 2 diabetic patients fasting plasma glucose and fructosamine levels were 61 and 64% higher, respectively, than in the healthy group (p < 0.001). In non-activated diabetic platelets PDHC activity, PDHC-E2, acetyl-CoA and ATP levels were 66, 70, 68 and 60%, higher, respectively, than in platelets from healthy controls (p < 0.01). 3-bromopyruvate (0.1 mM) decreased pyruvate dehydrogenase activity in healthy and diabetic platelets by 42% and 59%, respectively. Similar inhibitory effects were observed for acetyl-CoA and ATP levels, aggregation and TBARS accumulation rates. Succinate dehydrogenase activity was inhibited by 3-nitropropionate (10 mM) to 38 and 41% of control values in healthy and diabetic platelets, respectively, but affected neither function nor acetyl-CoA metabolism in platelets of both groups.

CONCLUSIONS

These data indicate that inhibition of pyruvate dehydrogenase excessive activity in diabetic platelets by 3-bromopyruvate may normalise their functional parameters through adjustment of acetyl-CoA/ATP levels to control values. Platelets from blood of diabetic patients display higher activities of pyruvate dehydrogenase complex (PDHC), higher levels of dihydrolipoate transacetylase (DLAT, E2 subunit of PDHC) as well as higher levels of acetyl-CoA yielding greater ATP/ADP accumulation than in platelets of normoglycemic subjects. Therefore, in diabetic platelets, thrombin caused higher release of ATP/ADP triggering excessive production of reactive oxygen species (ROS) and stronger aggregation compared to control platelets. In diabetic platelets, relative excess of DLAT in PDHC made them highly susceptible to 3-bromopyruvate (3BrP) inhibition. Resulting limitation of acetyl-CoA provision by 3-BrP normalised activity of diabetic platelets.

Native, Intact Glucagon-Like Peptide 1 Is a Natural Suppressor of Thrombus Growth Under Physiological Flow Conditions

OBJECTIVE

In patients with diabetes mellitus, increased platelet reactivity predicts cardiac events. Limited evidence suggests that DPP-4 (dipeptidyl peptidase 4) influences platelets via GLP-1 (glucagon-like peptide 1)-dependent effects. Because DPP-4 inhibitors are frequently used in diabetes mellitus to improve the GLP-1-regulated glucose metabolism, we characterized the role of DPP-4 inhibition and of native intact versus DPP-4-cleaved GLP-1 on flow-dependent thrombus formation in mouse and human blood. Approach and Results: An ex vivo whole blood microfluidics model was applied to approach in vivo thrombosis and study collagen-dependent platelet adhesion, activation, and thrombus formation under shear-flow conditions by multiparameter analyses. In mice, in vivo inhibition or genetic deficiency of DPP-4 (Dpp4^-/-), but not of GLP-1-receptors (Glp1r^-/-), suppressed flow-dependent platelet aggregation. In human blood, GLP-1(7-36), but not DPP-4-cleaved GLP-1(9-36), reduced thrombus volume by 32% and impaired whole blood thrombus formation at both low/venous and high/arterial wall-shear rates. These effects were enforced upon ADP costimulation and occurred independently of plasma factors and leukocytes. Human platelets did not contain detectable levels of GLP-1-receptor transcripts. Also, GLP-1(7-36) did not inhibit collagen-induced aggregation under conditions of stirring or stasis of platelets, pointing to a marked flow-dependent role.

CONCLUSIONS

Native, intact GLP-1 is a natural suppressor of thrombus growth under physiological flow conditions, with DPP-4 inhibition and increased intact GLP-1 suppressing platelet aggregation under flow without a main relevance of GLP-1-receptor on platelets.

A Critical Review of Proteomic Studies in Gestational Diabetes Mellitus

Gestational diabetes mellitus is a progressive and complex pregnancy complication, which threatens both maternal and fetal health. It is urgent to screen for specific biomarkers for early diagnosis and precise treatment, as well as to identify key moleculars to better understand the pathogenic mechanisms. In the present review, we comprehensively summarized recent studies of gestational diabetes using mass spectrometry-based proteomic technologies. Focused on the entire experimental design and proteomic results, we showed that these studies have covered a broad range of research contents in terms of sampling time, sample types, and outcome associations. Although most of the studies only stayed in the stage of initial discovery, several proteins were further verified to be efficient for disease diagnosis. Functional analysis of all the combined significant proteins also showed that a small number of proteins are known to be involved in the regulation of insulin or indirect signaling pathways. However, many factors such as diagnostic criteria, sample processing, proteomic method, and statistical method can greatly affect the identification of reproducible and reliable protein candidates. Thus, we further provided constructive suggestions and recommendations for carrying out proteomic or follow-up studies of gestational diabetes or other pregnancy complications in the future.

The variation degree of coagulation function is not responsible for extra risk of hemorrhage in gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is characterized as glucose intolerance of any degree that begins or first diagnosed during pregnancy. It possesses a higher risk of haemorrhage, which may be caused by the coagulation dysfunction. However, there has been no study focus on how coagulation state changes in the progress of GDM pregnancy. Our study is aimed to assess the association of coagulation function and haemorrhage in GDM.

METHODS

A total of 662 subjects (273 from a population-based study and 389 from a prospective cohort study) were selected to measure mean platelet volume (MPV), platelet distribution width (PDW), platelet (PLT), thrombocytocrit (PCT), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and fibrinogen (FIB). All pregnant individuals were divided into normal glucose tolerance (NGT) controls and GDM patients diagnosed between the 24th and 28th weeks of gestation.

RESULTS

Compared with NGT controls, GDM females showed shortened PT, shortened APTT, and increased blood FIB levels, while the platelet parameters MPV, PDW, PLT, and PCT remained unchanged in mid-pregnancy. By late pregnancy, the platelet parameters MPV, PDW, and PCT were increased in the GDM group compared with the NGT group, while PT and APTT were unchanged.

CONCLUSIONS

The GDM group was hypercoagulable compared with the NGT group rather than hypocoagulable as predicted, but still within the normal range. Therefore, our findings demonstrate that the variation degree of coagulation function is not responsible for extra risk of hemorrhage in GDM, and prevention of hemorrhage should focus on other causes.

Platelet Oxidative Stress and its Relationship with Cardiovascular Diseases in Type 2 Diabetes Mellitus Patients

Enhanced platelet activation and thrombosis are linked to various cardiovascular diseases (CVD). Among other mechanisms, oxidative stress seems to play a pivotal role in platelet hyperactivity. Indeed, upon stimulation by physiological agonists, human platelets generate and release several types of reactive oxygen species (ROS) such as O2 -, H2O2 or OH-, further amplifying the platelet activation response via various signalling pathways, including, formation of isoprostanes, Ca2+ mobilization and NO inactivation. Furthermore, excessive platelet ROS generation, incorporation of free radicals from environment and/or depletion of antioxidants induce pro-oxidant, pro-inflammatory and platelet hyperaggregability effects, leading to the incidence of cardiovascular events. Here, we review the current knowledge regarding the effect of oxidative stress on platelet signaling pathways and its implication in CVD such as type 2 diabetes mellitus. We also summarize the role of natural antioxidants included in vegetables, fruits and medicinal herbs in reducing platelet function via an oxidative stress-mediated mechanism.

Diabetes and baseline glucose are associated with inflammation, left ventricular function and short- and long-term outcome in acute coronary syndromes: role of the novel biomarker Cyr 61

Background

Hyperglycemia in the setting of an acute coronary syndrome (ACS) impacts short term outcomes, but little is known about longer term effects. We therefore designed this study to firstly determine the association between hyperglycemia and short term and longer term outcomes in patients presenting with ACS and secondly evaluate the prognostic role of diabetes, body mass index (BMI) and the novel biomarker Cyr61 on outcomes.

Methods

The prospective Special Program University Medicine-Acute Coronary Syndrome (SPUM-ACS) cohort enrolled 2168 patients with ACS between December 2009 and October 2012, of which 2034 underwent PCI (93.8%). Patients were followed up for 12 months. Events were independently adjudicated by three experienced cardiologists. Participants were recruited from four tertiary hospitals in Switzerland: Zurich, Geneva, Lausanne and Bern. Participants presenting with acute coronary syndromes and who underwent coronary angiography were included in the analysis. Patients were grouped according to history of diabetes (or HbA1c greater than 6%), baseline blood sugar level (BSL; < 6, 6–11.1 and > 11.1 mmol/L) and body mass index (BMI). The primary outcome was major adverse cardiac events (MACE) which was a composite of myocardial infarction, stroke and all-cause death. Secondary outcomes included the individual components of the primary endpoint, revascularisations, bleeding events (BARC classification) and cerebrovascular events (ischaemic or haemorrhagic stroke or TIA).

Results

Patients with hyperglycemia, i.e. BSL ≥ 11.1 mmol/L, had higher levels of C-reactive protein (CRP), white blood cell count (WBC), creatinine kinase (CK), higher heart rates and lower left ventricular ejection fraction (LVEF) and increased N-terminal pro-brain natriuretic peptide. At 30 days and 12 months, those with BSL ≥ 11.1 mmol/L had more MACE and death compared to those with BSL < 6.0 mmol/L or 6.0–11.1 mmol/L (HR-ratio 4.78 and 6.6; p < 0.001). The novel biomarker Cyr61 strongly associated with high BSL and STEMI and was independently associated with 1 year outcomes (HR 2.22; 95% CI 1.33–3.72; Tertile 3 vs. Tertile 1).

Conclusions and relevance

In this large, prospective, independently adjudicated cohort of in all comers ACS patients undergoing PCI, both a history of diabetes and elevated entry glucose was associated with inflammation and increased risk of MACE both at short and long-term. The mediators might involve increased sympathetic activation, inflammation and ischemia as reflected by elevated Cyr61 levels leading to larger levels of troponin and lower LVEF.

Trial registration Clinical Trial Registration Number: NCT01000701. Registered October 23, 2009

The Efficacy of P2Y12 Reactive Unit to Predict the Periprocedural Thromboembolic and Hemorrhagic Complications According to Clopidogrel Responsiveness and Safety of Modification of Dual Antiplatelet Therapy : A Meta-Analysis

The efficacy of P2Y12 reaction unit (PRU) of VerifyNow still remains as a controversial issue in neurointervention. So we investigated the usefulness of PRU of VerifyNow to predict the peri-procedural thromboembolic events (TE) and hemorrhagic events (HE). And we evaluated the safety of modified dual antiplatelet therapy (DAPT) or triple antiplatelet therapy (TAPT) for clopidogrel hyporesponders. We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Web of Science and Scopus on August 19 2018. Data was collected the 1) incidence of TE between clopidogrel responder and clopidogrel hypo-responder, 2) incidence of HE between clopidogrel hyper-responder and clopidogrel responder and hypo-responder, and 3) incidence of TE and HE between modified DAPT or TAPT and standard DAPT in clopidogrel hypo-responder. High cut-off value of PRU was defined as PRU >40% or <220. Fifteen studies were enrolled. Clopidogrel responder showed lower incidence of TE than hypo-responder (risk ratio [RR], 0.32; 95% confidence interval [CI], 0.17-0.61; p<0.001). With the high cut-off value of PRU, clopidogrel responder showed more lower incidence of TE than hypo-responder (RR, 0.11; 95% CI, 0.02-0.45; p=0.002). The incidence of periprocedural HE have higher on clopidogrel hyper-responder than clopidogrel responder and hypo-responder (RR, 4.26; 95% CI, 1.10-16.44; p=0.04; I2=66%). The incidence of periprocedural TE after changing regimen of DAPT for clopidogrel hypo-responder have a tendency to reduce, but there was no significant difference between modified DAPT or TAPT group and standard DAPT group (p>0.05). The incidence of periprocedural HE after changing regimen of DAPT for clopidogrel hypo-responder was no significant difference between modified DAPT or TAPT group and standard DAPT group (p>0.05). PRU is a useful tool as a predictor of peri-procedural TE or HE on neurointervention. PRU has a threshold effect of cut-off value to predict the peri-procedural TE. Modified DAPT or TAPT to prevent TE in clopidogrel hypo-responders could not reduce the incidence of TE. We should investigate the further research about modification of regiment on neurointervention.

Aspirin for Primary Prevention of Cardiovascular Disease in Diabetes: a Review of the Evidence

PURPOSE OF REVIEW

People with diabetes are at a higher risk of atherosclerotic cardiovascular disease (ASCVD) compared with those without diabetes. Though aspirin has been shown to have an overall net clinical benefit when used for secondary prevention of ASCVD in people with and without diabetes, the evidence for primary prevention, especially in those with diabetes, remains inconsistent. In this article, we review the latest studies examining the risks and benefits of aspirin use for primary prevention of ASCVD in adults with diabetes, discuss key aspects in assessing the risk-benefit ratio of aspirin use for primary prevention of ASCVD, and summarize current guidelines from professional societies on aspirin use for primary prevention in adults with diabetes.

RECENT FINDINGS

In the general population, past studies have shown no difference in the beneficial effect of aspirin for primary cardiovascular disease prevention by diabetes status. However, several randomized controlled studies and meta-analyses in adults with diabetes have shown lack of net clinical benefit of aspirin use for primary prevention of ASCVD. The recent ASCEND trial documented cardiovascular benefit of aspirin for primary prevention in adults with diabetes but suggested that the increased risk of bleeding may outweigh the cardiovascular benefit. The decision to initiate aspirin for primary prevention of ASCVD must be considered carefully on an individual basis to balance the cardiovascular benefit and bleeding risk in all patients, especially those with diabetes. A multifactorial approach that focuses on managing ASCVD risk factors such as hypertension, dyslipidemia, dysglycemia, and smoking is recommended in all patients. More research is needed to identify subgroups of people with diabetes who are more likely to benefit from aspirin use for primary prevention of ASCVD and develop better antithrombotic strategies that shift the risk-benefit balance toward an overall net clinical benefit.

Increased erythrocyte- and platelet-derived microvesicles in newly diagnosed type 2 diabetes mellitus

AIM

To investigate the thrombotic microenvironment in early stages of type 2 diabetes mellitus measuring platelet-derived, endothelial-derived and erythrocyte-derived microvesicles.

METHODS

We recruited 50 newly diagnosed type 2 diabetes mellitus patients who did not receive glucose-lowering treatment except for metformin and 25 matched non-type 2 diabetes mellitus volunteers. Microvesicles were measured with flow cytometry, glycated haemoglobin with high-performance liquid chromatography and advanced glycation end products with enzyme-linked immunosorbent assay.

RESULTS

Type 2 diabetes mellitus patients showed significantly higher levels of platelet-derived microvesicles [195/μL (115-409) vs 110/μL (73-150), p = 0.001] and erythrocyte-derived microvesicles [26/μL (9-100) vs 9/μL (4-25), p = 0.007] compared to non-type 2 diabetes mellitus individuals. Platelet-derived microvesicles were positively associated with fasting blood glucose (p = 0.026) and glycated haemoglobin (p = 0.002). Erythrocyte-derived microvesicles were also positively associated with fasting blood glucose (p = 0.018) but not with glycated haemoglobin (p = 0.193). No significant association was observed between platelet-derived microvesicles (p = 0.126) or erythrocyte-derived microvesicles (p = 0.857) and advanced glycation end products. Erythrocyte-derived microvesicles predicted the presence of type 2 diabetes mellitus, independently of platelet-derived microvesicles.

CONCLUSION

In newly diagnosed type 2 diabetes mellitus, ongoing atherothrombosis is evident during the early stages as evidenced by increased microvesicles levels. Furthermore, the association with glycemic profile suggests that microvesicles represent not only a novel mechanism by which hyperglycemia amplifies thrombotic tendency in type 2 diabetes mellitus but also early markers of thrombosis highlighting the need for earlier management of hyperglycemia.

Significance of circulating microRNAs in diabetes mellitus type 2 and platelet reactivity: bioinformatic analysis and review

In the light of growing global epidemic of type 2 diabetes mellitus (T2DM), significant efforts are made to discover next-generation biomarkers for early detection of the disease. Multiple mechanisms including inflammatory response, abnormal insulin secretion and glucose metabolism contribute to the development of T2DM. Platelet activation, on the other hand, is known to be one of the underlying mechanisms of atherosclerosis, which is a common T2DM complication that frequently results in ischemic events at later stages of the disease. Available data suggest that platelets contain large amounts of microRNAs (miRNAs) that are found in circulating body fluids, including the blood. Since miRNAs have been illustrated to play an important role in metabolic homeostasis through regulation of multiple genes, they attracted substantial scientific interest as diagnostic and prognostic biomarkers in T2DM. Various miRNAs, as well as their target genes are implicated in the complex pathophysiology of T2DM. This article will first review the different miRNAs studied in the context of T2DM and platelet reactivity, and subsequently present original results from bioinformatic analyses of published reports, identifying a common gene (PRKAR1A) linked to glucose metabolism, blood coagulation and insulin signalling and targeted by miRNAs in T2DM. Moreover, miRNA–target gene interaction networks built upon Gene Ontology information from electronic databases were developed. According to our results, miR-30a-5p, miR-30d-5p and miR-30c-5p are the most widely regulated miRNAs across all specified ontologies, hence they are the most promising biomarkers of T2DM to be investigated in future clinical studies.

Prevalence of pre-existing dysglycaemia among inpatients with acute coronary syndrome and associations with outcomes

AIMS

We aimed to confirm the hypothesis that dysglycaemia including in the pre-diabetes range affects a majority of patients admitted with acute coronary syndrome (ACS) and is associated with worse outcomes.

METHODS

In this prospective observational cohort study, consecutive inpatients aged ≥ 54 years with ACS were uniformly tested and categorised into diabetes (prior diagnosis/ HbA1c ≥ 6.5%, ≥48 mmol/mol), pre-diabetes (HbA1c 5.7-6.4%, 39-47 mmol/mol) and no diabetes (HbA1c ≤ 5.6%, ≤38 mmol/mol) groups.

RESULTS

Over two years, 847 consecutive inpatients presented with ACS. 313 (37%) inpatients had diabetes, 312 (37%) had pre-diabetes and 222 (25%) had no diabetes. Diabetes, compared with no diabetes, was associated with higher odds of acute pulmonary oedema (APO, odds ratio, OR 2.60, p < 0.01), longer length of stay (LOS, incidence rate ratio, IRR 1.18, p = 0.02) and, 12-month ACS recurrence (OR 1.86, p = 0.046) after adjustment, while no significant associations were identified for pre-diabetes. Analysed as a continuous variable, every 1% (11 mmol/mol) increase in HbA1c was associated with increased odds of APO (OR 1.28, P = 0.002) and a longer LOS (IRR 1.05, P = 0.03).

CONCLUSIONS

The high prevalence of dysglycaemia and association with poorer clinical outcomes justifies routine HbA1c testing to identify individuals who may benefit from cardioprotective anti-hyperglycaemic agents and, lifestyle modification to prevent progression of pre-diabetes.

Increased exercise-related platelet activation assessed by impedance aggregometry in diabetic patients despite aspirin therapy

Aspirin is widely used for the prevention of thromboembolic diseases, but inhibition of platelet aggregation (PA) is not uniform. Additionally, aspirin has been shown to be ineffective in blunting PA in response to exercise in patients with coronary artery disease (CAD). Limited data exists about platelet function following acute exercise in diabetics taking aspirin. In our study, we aimed to investigate PA before and after exercise stress test in type-2 diabetic patients taking aspirin. Forty-three patients with type-2 diabetes mellitus (DM) and 36 subjects (age- and sex-matched) as control group were included prospectively. All participants were under aspirin (100 mg/day) therapy for at least 1 week. The measures of PA were assessed by impedance aggregometry using arachidonic acid as an agonist (ASPI test). Blood samplings were undertaken before and immediately after treadmill exercise test. At rest, diabetic and control groups had comparable pre-exercise PA (22.97 ± 14.57 versus 22.11 ± 12.71 AU min, p = NS, respectively). After treadmill exercise, both groups showed significantly higher absolute increase (9.02 ± 13.08 and 3.66 ± 5.87 AU min, p < 0.01, p < 0.01, respectively) and percent (%) increase (45.67 ± 49.34 and 24.04 ± 46.59 AU min, p < 0.01, p = 0.01, respectively) in PA. Both absolute increase (p < 0.05) and % increase (p < 0.05) in PA were significantly higher in DM group compared to the control group. Multiple regression analysis revealed that high-sensitive C-reactive protein (p = 0.014) was independent predictor of absolute increase PA. Our study showed that aspirin has limited effect in inhibiting exercise-induced PA, even in the absence of documented CAD. The increase in PA following exercise was significantly greater in patients with DM compared with controls.

Increased levels of the megakaryocyte and platelet expressed cysteine proteases stefin A and cystatin A prevent thrombosis

Increased platelet activity occurs in type 2 diabetes mellitus (T2DM) and such platelet dysregulation likely originates from altered megakaryopoiesis. We initiated identification of dysregulated pathways in megakaryocytes in the setting of T2DM. We evaluated through transcriptomic analysis, differential gene expressions in megakaryocytes from leptin receptor-deficient mice (db/db), exhibiting features of human T2DM, and control mice (db/+). Functional gene analysis revealed an upregulation of transcripts related to calcium signaling, coagulation cascade and platelet receptors in diabetic mouse megakaryocytes. We also evidenced an upregulation (7- to 9.7-fold) of genes encoding stefin A (StfA), the human ortholog of Cystatin A (CSTA), inhibitor of cathepsin B, H and L. StfA/CSTA was present in megakaryocytes and platelets and its expression increased during obesity and diabetes in rats and humans. StfA/CSTA was primarily localized at platelet membranes and granules and was released upon agonist stimulation and clot formation through a metalloprotease-dependent mechanism. StfA/CSTA did not affect platelet aggregation, but reduced platelet accumulation on immobilized collagen from flowing whole blood (1200 s^-1). In-vivo, upon laser-induced vascular injury, platelet recruitment and thrombus formation were markedly reduced in StfA1-overexpressing mice without affecting bleeding time. The presence of CA-074Me, a cathepsin B specific inhibitor significantly reduced thrombus formation in-vitro and in-vivo in human and mouse, respectively. Our study identifies StfA/CSTA as a key contributor of platelet-dependent thrombus formation in both rodents and humans.

The effect of mild agonist stimulation on the platelet reactivity in patients with type 2 diabetes mellitus

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) have accelerated atherosclerosis as a pro thrombotic state that is associated with the platelet activation priming. Platelets, which undergo the continuous mild stimulation, may lose their sensitivity to react to a strong stimulation. The present study aimed to investigate activation responses of platelets to mild and subsequent strong stimulations in patients with T2DM and healthy individuals.

METHODS

Blood samples, which were taken from 40 patients with T2DM and 35 healthy individuals, were collected into the citrate containing tubes. The samples were subjected to the soft centrifugation to prepare the platelet rich plasma (PRP). Platelets in PRP samples were treated at a low (1 μM) concentration and then at a high (10 μM) concentration of ADP. Before and after stimulation with different doses of ADP, levels of CD62P expression and formation of platelet micro particles (PMPs) were measured using a flow cytometry method.

RESULTS

The platelets from patients with T2DM had higher levels of CD62P expression before any stimulation (P = 0.003) than control samples. Platelets, which underwent the mild stimulation, indicated lower responses to CD62P expression, but higher PMPs formation after stimulation with high dose of ADP. Patients with T2DM had higher platelet micro particles in all states with the ADP stimulation. (P = 0.004, SD: ±74.52).

CONCLUSIONS

The flow cytometry data indicated that platelets were pre-active and associated with metabolic conditions in patients with type 2 diabetes mellitus. The induction of desensitization state helped platelets to reduce the platelet activation and sensitivity to ADP in a diabetic environment. Furthermore, the production of platelets micro-particles was high in the patients; and desensitized platelets were more susceptible to shedding of micro-particles.

Platelet Indices Alterations in Children With Type 1 Diabetes Mellitus

Platelet (PLT) hyperactivity is a key factor which contributes to cardiovascular complications in patients with type 2 diabetes mellitus even in preclinical stages of disease. To the best of our knowledge, there is limited researches in this regard among patients with type 1 diabetes. The aim of this study was to evaluate hematologic indices indicating PLT activity in children with type 1 diabetes. This was a case-control study which was conducted on 166 inpatients in 17 Shahrivar children hospital, Rasht, Iran during April 2016 to April 2017. Cases and controls were 83 children with type 1 diabetes mellitus and 83 children hospitalized for thorough assessment of short stature, respectively. Groups were matched for age and sex. Demographic characteristics and hematologic variables were assessed. The Shapiro-Wilk test was used to determine the normality of the distribution. Results for continuous and categorical variables were demonstrated as mean±SD and number and percent, respectively. Continuous variables without normal distribution were demonstrated as median (interquartile range). The χ/Fisher's exact test was used to compare categorical variables. The normal and non-normal distributed quantitative variables were respectively assessed by independent T-test or Mann-Whitney U test. P-value <0.05 noted statistical significance. The median (interquartile range) age of all children was 10 (6 to 13) years old. Thirty-five (42.2) of patients with diabetes and 35 (42.2) of control group were male individuals. There were positive correlation between age (r=0.370; P=0.001), hemoglobin (r=0.278; P=0.009), blood sugar (r=0.243; P=0.027), PLT distribution width (r=0.229; P=0.038), plateletcrit (PCT) (r=0.290; P=0.008), PLT to lymphocyte ratio (r=0.230; P=0.037) and glycosylated hemoglobin in children with diabetes. The cut-off point of PCT was 0.19 (sensitivity=87.8%, specificity=66.7%). Only increased PCT (>0.19) was related with poor metabolic control and can put the patients to the risk of future cardiovascular events. The authors recommend considering multiple PLT parameters, and not just one of them, and even designing a scoring system in terms of PLT parameters for type 1 diabetes mellitus management programs.

Forms of extracellular mitochondria and their impact in health

Mitochondria play an important role as an intracellular energy plant and signaling organelle. However, mitochondria also exist outside cells where they could mediate cell-to-cell communication, repair and serve as an activator of the immune response. Their effects depend on the mitochondrial state or the form in which it is present, either as a whole functional structure as fragments or only as mitochondrial DNA. Herein, we provide evidence of why extracellular mitochondria and their varying forms are considered regenerative factors or pro-inflammatory activators. Understanding these aspects will provide the base of their use in therapy or as a biomarker of disease severity and prognosis.

Prevention of atherothrombotic events in patients with diabetes mellitus: from antithrombotic therapies to new-generation glucose-lowering drugs

Diabetes mellitus is an important risk factor for a first cardiovascular event and for worse outcomes after a cardiovascular event has occurred. This situation might be caused, at least in part, by the prothrombotic status observed in patients with diabetes. Therefore, contemporary antithrombotic strategies, including more potent agents or drug combinations, might provide greater clinical benefit in patients with diabetes than in those without diabetes. In this Consensus Statement, our Working Group explores the mechanisms of platelet and coagulation activity, the current debate on antiplatelet therapy in primary cardiovascular disease prevention, and the benefit of various antithrombotic approaches in secondary prevention of cardiovascular disease in patients with diabetes. While acknowledging that current data are often derived from underpowered, observational studies or subgroup analyses of larger trials, we propose antithrombotic strategies for patients with diabetes in various cardiovascular settings (primary prevention, stable coronary artery disease, acute coronary syndromes, ischaemic stroke and transient ischaemic attack, peripheral artery disease, atrial fibrillation, and venous thromboembolism). Finally, we summarize the improvements in cardiovascular outcomes observed with the latest glucose-lowering drugs, and on the basis of the available evidence, we expand and integrate current guideline recommendations on antithrombotic strategies in patients with diabetes for both primary and secondary prevention of cardiovascular disease.

Caspase 3/ROCK1 pathway mediates high glucose-induced platelet microparticles shedding

BACKGROUND

Platelet microparticles (PMPs) are closely associated with diabetic macrovascular complications. This study aimed to explore the underlying mechanisms of high glucose-induced PMPs generation.

METHODS

Washed platelets, obtained from the plasma of healthy male Sprague-Dawley rats, were incubated with high glucose. PMPs were isolated using gradient centrifugation and counted by flow cytometry. Expression and activity of ROCK1 and caspase3 were evaluated by real-time PCR, Western blotting, and activity assay kit.

RESULTS

High glucose enhanced PMPs shedding in the presence of collagen. The mRNA and protein levels of ROCK1, but not ROCK2, were increased in platelets incubated with high glucose. Y-27632, an inhibitor of ROCK, blocked the increased PMPs shedding induced by high glucose. Expression and activity of caspase3 were elevated in platelets under the high glucose conditions. Z-DVED-FMK, a caspase3 inhibitor, inhibited ROCK1 activity and decreased the PMPs generation under high glucose.

CONCLUSION

High glucose increased PMPs shedding via caspase3-ROCK1 signal pathway.

Platelet-endothelial cell interactions modulate smooth muscle cell phenotype in an in vitro model of type 2 diabetes mellitus

Platelet (PLT)-endothelial cell (EC) interaction appears to contribute to phenotypic transition of vascular smooth muscle cells (VSMCs), which play an important role in the physiological and pathological process of vascular complications in type 2 diabetes mellitus (DM2). However, the precise mechanisms by which interactions between PLTs and ECs affect VSMC phenotype have largely remained unclear. We determined the effect of diabetic PLT-EC interaction to influence VSMC migration, proliferation, and phenotypic transformation in triple-cell coculture models using the quantitative real-time PCR, Western blot, fluorescence microscopy, wound scratch assays, CCK-8 assays, and gelatin zymography assays. Our results revealed DM2 PLT-EC interaction to be associated with a significant downregulation of VSMC-specific contractile phenotypic genes and proteins, including SM22α, smooth muscle actin, Smoothelin-B, and smooth muscle-myosin heavy chain. Inversely, VSMC-specific proliferative phenotype gene and protein levels, including cyclin D1 and 2, nonmuscle myosin heavy chain B, and PCNA were in upregulation. Furthermore, the DM2-originated PLT-EC interaction promoted the expression level of transforming growth factor-β1, and the PI3K/Akt and matrix metalloproteinase 9 signaling pathway was activated subsequently. Finally, these reactions contributed to a synthetic phenotype of VSMCs, including the proliferation, migration, and gelatinolytic activities. These findings suggest that PLT-EC interaction modulates the phenotypic transition of VSMCs between a contractile and proliferative/synthetic phenotype under diabetic conditions, conceivably providing important implications regarding the mechanisms controlling the VSMC phenotypic transition and the development of cardiovascular complications.

Diabetes and Platelet Response to Low-Dose Aspirin

CONTEXT

Previous studies have suggested less cardioprotective benefit of aspirin in adults with diabetes, raising concerns about "aspirin resistance" and potentially reduced effectiveness for prevention of cardiovascular disease (CVD).

OBJECTIVE

To examine differences in platelet response to aspirin by diabetes status.

DESIGN, SETTING, PARTICIPANTS

We examined platelet response before and after aspirin (81 mg/day for 14 days) in 2113 adults (175 with diabetes, 1,938 without diabetes), in the Genetic Study of Aspirin Responsiveness cohort, who had family history of early-onset CVD.

MAIN OUTCOME MEASURES

In vivo platelet activation (urinary thromboxane B2), in vitro platelet aggregation to agonists (arachidonic acid, adenosine diphosphate, collagen), and platelet function analyzer-100 closure time.

RESULTS

Although adults with diabetes had higher in vivo platelet activation before aspirin, the reduction in in vivo platelet activation after aspirin was similar in those with vs without diabetes. Likewise, the reduction in multiple in vitro platelet measures was similar after aspirin by diabetes status. In regression analyses adjusted for age, sex, race, BMI, smoking, platelet counts, and fibrinogen levels, in vivo platelet activation remained higher in adults with vs without diabetes after aspirin (P = 0.04), but this difference was attenuated after additional adjustment for preaspirin levels (P = 0.10). No differences by diabetes status were noted for any of the in vitro platelet measures after aspirin in fully adjusted models that also accounted for preaspirin levels.

CONCLUSIONS

In vitro platelet response to aspirin does not differ by diabetes status, suggesting no intrinsic differences in platelet response to aspirin. Instead, factors extrinsic to platelet function should be investigated to give further insights into aspirin use for primary prevention in diabetes.

Significance of urinary 11-dehydro-thromboxane B2 in age-related diseases: Focus on atherothrombosis

Platelet activation plays a key role in atherogenesis and atherothrombosis. Biochemical evidence of increased platelet activation in vivo can be reliably obtained through non-invasive measurement of thromboxane metabolite (TXM) excretion. Persistent biosynthesis of TXA₂ has been associated with several ageing-related diseases, including acute and chronic cardio-cerebrovascular diseases and cardiovascular risk factors, such as cigarette smoking, type 1 and type 2 diabetes mellitus, obesity, hypercholesterolemia, hyperhomocysteinemia, hypertension, chronic kidney disease, chronic inflammatory diseases. Given the systemic nature of TX excretion, involving predominantly platelet but also extraplatelet sources, urinary TXM may reflect either platelet cyclooxygenase-1 (COX-1)-dependent TX generation or COX-2-dependent biosynthesis by inflammatory cells and/or platelets, or a combination of the two, especially in clinical settings characterized by low-grade inflammation or enhanced platelet turnover. Although urinary 11-dehydro-TXB₂ levels are largely suppressed with low-dose aspirin, incomplete TXM suppression by aspirin predicts the future risk of vascular events and death in high-risk patients and may identify individuals who might benefit from treatments that more effectively block in vivo TX production or activity. Several disease-modifying agents, including lifestyle intervention, antidiabetic drugs and antiplatelet agents besides aspirin have been shown to reduce TX biosynthesis. Taken together, these aspects may contribute to the development of promising mechanism-based therapeutic strategies to reduce the progression of atherothrombosis. We intended to critically review current knowledge on both the pathophysiological significance of urinary TXM excretion in clinical settings related to ageing and atherothrombosis, as well as its prognostic value as a biomarker of vascular events.

Prognostic value of hyperglycemia on-admission in diabetic versus non-diabetic patients presenting with ST-elevation myocardial infarction in Tunisia

BACKGROUND

Hyperglycemia on-admission is a powerful predictor of adverse events in patients presenting for ST-elevation myocardial infarction (STEMI).

AIM

In this study, we sought to determine the prognostic value of hyperglycemia on-admission in Tunisian patients presenting with STEMI according to their diabetic status.

METHODS

Patients presenting to our center between January 1998 and September 2014 were enrolled. Hyperglycemia was defined as a glucose level ≥11mmol/L. In-hospital prognosis was studied in diabetic and non-diabetic patients. The predictive value for mortality of glycemia level on-admission was assessed by mean of the area under receiver operating characteristic (ROC) curve calculation.

RESULTS

A total of 1289 patients were included. Mean age was 60.39±12.8years and 977 (77.3%) patients were male. Prevalence of diabetes mellitus was 70.2% and 15.2% in patients presenting with and without hyperglycemia, respectively (p<0.001). In univariate analysis, hyperglycemia was associated to in-hospital death in diabetic (OR: 8.85, 95% CI: 2.11-37.12, p<0.001) and non-diabetic patients (OR: 2.57, 95% CI: 1.39-4.74, p=0.002). In multivariate analysis, hyperglycemia was independently predictive of in-hospital death in diabetic patients (OR: 9.6, 95% CI: 2.18-42.22, p=0.003) but not in non-diabetic patients (OR: 1.93, 95% CI: 0.97-3.86, p=0.06). Area under ROC curve of glycemia as a predictor of in-hospital death was 0.792 in diabetic and 0.676 in non-diabetic patients.

CONCLUSION

In patients presenting with STEMI, hyperglycemia was associated to hospital death in diabetic and non-diabetic patients in univariate analysis. In multivariate analysis, hyperglycemia was independently associated to in-hospital death in diabetic but not in non-diabetic patients.

Monocytes of Different Subsets in Complexes with Platelets in Patients with Myocardial Infarction

Acute myocardial infarction (AMI) is associated with activation of various cells, including platelets that form monocyte-platelet complexes (MPCs). Here, we analysed MPC in vivo and in vitro and investigated the abilities of different monocyte subclasses to form MPC, the characteristics of the cells involved in MPC formation and MPC changes in AMI. We identified MPC by co-staining for platelet antigen CD41a and monocyte antigens CD14 and CD16. Platelet activation was evaluated from expression of phosphatidylserine as revealed by annexin V. Our results confirm published data and provide new information regarding the patterns of MPC in AMI patients. We found that the patterns of platelet aggregation with monocytes were different in AMI patients and controls: (1) in AMI patients, MPC formed by intermediate monocytes carry more platelets whereas in healthy controls more platelets aggregated with classical monocytes; (2) the numbers of MPC in AMI patients, being already higher than in controls, were further increased if these patients suffered various in-hospital complications; (3) on the basis of the CD41a fluorescence of the antibody-stained MPC, some of the aggregates seem to consist of monocytes and platelet-derived extracellular vesicles (EVs); (4) aggregation of monocytes with platelet EV occurred in in vitro experiments; and (5) these experiments demonstrated that monocytes from AMI patients aggregate with both platelets and platelet EVs more efficiently than do monocytes from controls. MPC in AMI patients may play an important role in this pathology.

Quantifying Platelet Margination in Diabetic Blood Flow

Patients with type 2 diabetes mellitus (T2DM) develop thrombotic abnormalities strongly associated with cardiovascular diseases. In addition to the changes of numerous coagulation factors such as elevated levels of thrombin and fibrinogen, the abnormal rheological effects of red blood cells (RBCs) and platelets flowing in blood are crucial in platelet adhesion and thrombus formation in T2DM. An important process contributing to the latter is the platelet margination. We employ the dissipative particle dynamics method to seamlessly model cells, plasma, and vessel walls. We perform a systematic study on RBC and platelet transport in cylindrical vessels by considering different cell shapes, sizes, and RBC deformabilities in healthy and T2DM blood, as well as variable flowrates and hematocrit. In particular, we use cellular-level RBC and platelet models with parameters derived from patient-specific data and present a sensitivity study. We find T2DM RBCs, which are less deformable compared to normal RBCs, lower the transport of platelets toward the vessel walls, whereas platelets with higher mean volume (often observed in T2DM) lead to enhanced margination. Furthermore, increasing the flowrate or hematocrit enhances platelet margination. We also investigated the effect of platelet shape and observed a nonmonotonic variation with the highest near-wall concentration corresponding to platelets with a moderate aspect ratio of 0.38. We examine the role of white blood cells (WBCs), whose count is increased notably in T2DM patients. We find that WBC rolling or WBC adhesion tends to decrease platelet margination due to hydrodynamic effects. To the best of our knowledge, such simulations of blood including all blood cells have not been performed before, and our quantitative findings can help separate the effects of hydrodynamic interactions from adhesive interactions and potentially shed light on the associated pathological processes in T2DM such as increased inflammatory response, platelet activation and adhesion, and ultimately thrombus formation.

Diabetes and antiplatelet therapy: from bench to bedside

Diabetes mellitus (DM) is a metabolic disorder associated with accelerated atherogenesis and an increased risk of atherothrombotic complications. Multiple mechanisms contribute to the pro-thrombotic status which characterizes DM patients underscoring the importance of antiplatelet therapies used for secondary prevention in these patients. For many years, dual antiplatelet therapy (DAPT) with aspirin and the P2Y₁₂ inhibitor clopidogrel has represented the mainstay of treatment following an acute coronary syndrome (ACS) or in patients undergoing percutaneous coronary interventions (PCI). Although DAPT reduces the incidence of atherothrombotic recurrences, these rates remain high in DM patients underscoring the need for more efficacious therapies. Oral platelet P2Y₁₂ receptor inhibitors with enhanced potency, such as prasugrel and ticagrelor, as well as antiplatelet therapies such as vorapaxar inhibiting the thrombin-mediated platelet signaling pathway, constitute treatment opportunities for patients with DM and have shown to be associated with a greater reduction in ischemic recurrences, albeit at the cost of more bleeding. This article reviews currently available antiplatelet agents and delivers an update on the advances and drawbacks of these agents used for secondary prevention in DM patients experiencing an ACS or undergoing PCI.

Prasugrel or ticagrelor in patients with acute coronary syndrome and diabetes: a propensity matched substudy of RENAMI

Introduction:

The safety and efficacy of prasugrel and ticagrelor in patients with diabetes mellitus presenting with acute coronary syndrome and treated with percutaneous coronary intervention remain to be assessed.

Methods:

All diabetes patients admitted for acute coronary syndrome and enrolled in the REgistry of New Antiplatelets in patients with Myocardial Infarction (RENAMI) were compared before and after propensity score matching. Net adverse cardiovascular events (composite of death, stroke, myocardial infarction and BARC 3–5 bleedings) and major adverse cardiovascular events (composite of death, stroke and myocardial infarction) were the co-primary endpoints. Single components of primary endpoints were secondary endpoints.

Results:

Among 4424 patients enrolled in RENAMI, 462 and 862 diabetes patients treated with prasugrel and ticagrelor, respectively, were considered. After propensity score matching, 386 patients from each group were selected. At 19±5 months, major adverse cardiovascular events and net adverse cardiovascular events were similar in the prasugrel and ticagrelor groups (5.4% vs. 3.4%, P=0.16 and 6.7% vs. 4.1%, P=0.11, respectively). Ticagrelor was associated with a lower risk of death and BARC 2–5 bleeding when compared to prasugrel (2.8% vs. 0.8%, P=0.031 and 6.0% vs. 2.6%, P=0.02, respectively) and a clear but not significant trend for a reduction of BARC 3–5 bleeding (2.3% vs. 0.8%, P=0.08). There were no significant differences in myocardial infarction recurrence and stent thrombosis.

Conclusion:

Diabetes patients admitted for acute coronary syndrome seem to benefit equally in terms of major adverse cardiovascular events from ticagrelor or prasugrel use. Ticagrelor was associated with a significant reduction in all-cause death and bleedings, without differences in recurrent ischaemic events, which should be confirmed in dedicated randomised controlled trials.

Changes in platelet morphology indices in relation to duration of disease and glycemic control in children with type 1 diabetes mellitus

BACKGROUND

There is limited data on platelet alterations in children with type 1 diabetes mellitus (T1DM). We planned to study the effect of glycemic control and duration of T1DM on platelet morphology in children with T1DM.

METHODS

We conducted an observational study on 260 children; 130 with T1DM (cases) and 130 healthy controls, in a tertiary care pediatric hospital. Platelet indices including Platelet count (PLT), Mean Platelet Volume (MPV), Platelet Distribution Width (PDW), Platelet-Large cell ratio (P-LCR), Plateletcrit (PCT) were measured, and their means were compared between cases and controls and various subgroups among the cases.

RESULTS

The MPV, PDW and P-LCR were significantly higher (p < 0.05) in cases when compared to controls and in children with suboptimal glycemic control compared to optimal control. PLT was considerably lower in cases compared to controls. In children with new-onset T1DM, only PDW was significantly raised when compared to controls. MPV and P-LCR had a significant positive correlation with duration of T1DM.

CONCLUSIONS

Children with T1DM have altered morphological parameter(s) which progress over time. Poor glycemic control is a significant risk factor for abnormal platelet indices.

Pharmacogenetic and clinical predictors of response to clopidogrel plus aspirin after acute coronary syndrome in Egyptians

OBJECTIVES

Dual antiplatelet therapy (DAPT) with aspirin and clopidogrel reduces the risk for recurrent cardiovascular events after acute coronary syndrome (ACS). However, there is significant variation in response to DAPT that may be influenced by both genetic and nongenetic factors. This study aimed to assess the effect of genetic polymorphisms in PON-1, PEAR-1, P2Y12, CES1, and CYP2C19, along with clinical, demographic, and social factors, on variation in response to DAPT in Egyptians.

PARTICIPANTS AND METHODS

This study included 230 Egyptians treated with clopidogrel 75 mg/day and aspirin 81 mg/day for at least 12 months following their first ACS. Simple and multivariable logistic regression analyses were carried out to identify factors associated with major adverse cardiovascular events (MACE), defined as the occurrence of recurrent ACS, ischemic stroke, stent-related revascularization, or death, in clopidogrel-treated participants.

RESULTS

Using multivariable logistic regression analysis, the CYP2C19*2 polymorphism was the only genetic predictor of MACE [odds ratio (OR): 2.23, 95% confidence interval (CI): 1.15-4.33, P=0.01]. In addition, proton pump inhibitor use (OR: 4.77, 95% CI: 1.47-15.54, P=0.009) and diabetes (OR: 1.83, 95% CI: 1.03-3.26, P=0.03) were associated with higher cardiovascular risk, whereas statin use was associated with lower risk (OR: 0.43, 95% CI: 0.25-0.76, P=0.003). The contribution of these four genetic and nongenetic factors explained 19% of the variability in risk for MACE in Egyptians treated with DAPT.

CONCLUSION

These results highlight that CYP2C19*2, along with diabetes, and use of proton pump inhibitor and statin are important factors jointly associated with variability in clinical response to DAPT following ACS in Egyptians.

Endothelial dysfunction and platelet hyperactivity in type 2 diabetes mellitus: molecular insights and therapeutic strategies

The incidence and prevalence of diabetes mellitus is rapidly increasing worldwide at an alarming rate. Type 2 diabetes mellitus (T2DM) is the most prevalent form of diabetes, accounting for approximately 90-95% of the total diabetes cases worldwide. Besides affecting the ability of body to use glucose, it is associated with micro-vascular and macro-vascular complications. Augmented atherosclerosis is documented to be the key factor leading to vascular complications in T2DM patients. The metabolic milieu of T2DM, including insulin resistance, hyperglycemia and release of excess free fatty acids, along with other metabolic abnormalities affects vascular wall by a series of events including endothelial dysfunction, platelet hyperactivity, oxidative stress and low-grade inflammation. Activation of these events further enhances vasoconstriction and promotes thrombus formation, ultimately resulting in the development of atherosclerosis. All these evidences are supported by the clinical trials reporting the importance of endothelial dysfunction and platelet hyperactivity in the pathogenesis of atherosclerotic vascular complications. In this review, an attempt has been made to comprehensively compile updated information available in context of endothelial and platelet dysfunction in T2DM.