Effects of improved metabolic control on platelet reactivity in patients with type 2 diabetes mellitus following coronary angioplasty

Effect of oral versus parenteral vitamin D3 supplementation on nuclear factor-κB and platelet aggregation in type 2 diabetic patients

Platelet hyperactivity is one of the key factors implicated in the development and progression of diabetic vascular complications. Activated platelets mediate leukocyte recruitment that further enhances inflammatory responses in vascular wall ultimately resulting in atherosclerotic complications. Since vitamin D insufficiency is highly prevalent in diabetics, we aimed to evaluate the effect of three dosage forms of vitamin D supplementation on lipid profile, NF-κB, platelet aggregation, and platelet calcium content in type 2 diabetic patients. Type 2 diabetic patients were randomized to receive daily (4000 IU/day) or weekly (50 000 IU/week) oral vitamin D3 for 3 months. Another group received a single parenteral dose (300 000 IU) of vitamin D3, whereas the control group received their antidiabetic drug(s) alone. Serum 25(OH)D, total cholesterol, triglycerides, high- and low-density lipoprotein cholesterol, NF-κB, and platelet aggregation were measured at the beginning and 3 months after vitamin D supplementation. Platelet calcium content was evaluated by measuring the fluorescence intensity of Rhod-2-stained platelets by confocal fluorescence microscopy. Results showed that serum 25(OH)D3 levels significantly increased in all vitamin D3-treated groups. However, the mean level for parenteral treated group was significantly lower than oral-treated groups. Oral and parenteral treatment were also able to decrease NF-κB level, platelet aggregation, and platelet calcium content. However, both oral doses of vitamin D3 were superior to the single parenteral dose. In conclusion, restoring normal levels of vitamin D is an important determinant to maintain normal platelet function and reduce inflammation. Nevertheless, further long-term studies are still needed.

Efficacy and safety of intensive versus conventional glucose targets in people with type 2 diabetes: a systematic review and meta-analysis

OBJECTIVE

The aim of study is to re-evaluate the risk-benefits of intensive glycemic control in the context of multi-factorial intervention in adults with T2D.

METHODS

We searched Ovid MEDLINE, Embase, Cochrane, and CINHAL for randomized control trials comparing standard glucose targets to intensive glucose targets with pre-specified HbA_1clevels. Subgroup analysis was also performed to account for the inclusion of glucose only versus multi-factorial intervention trials. Results are reported as risk ratio (RR) and 95% confidence interval (CI).

RESULTS

Fifty-seven publications including 19 trials were included. Compared to conventional glycemic control, intensive glycemic control decreased the risk of non-fatal myocardial infarction (0.8, 0.7-0.91), macroalbuminuria (0.72, 0.5--0.87), microalbuminuria (0.67, 0.52-0.85), major amputation (0.6, 0.38-0.96), retinopathy (0.75 ,0.63-0.9), and nephropathy (0.78, 0.63-0.97). The risk of hypoglycemia increased with intensive glycemic control than conventional treatment (2.04, 1.34-3.1). No reduction in all-cause or cardiovascular mortality was observed. However, in the context of multifactorial intervention, intensive glucose control was associated with a significant reduction in all-cause mortality (0.74, 0.57-0.95).

CONCLUSION

Targeting HbA_1c levels should be individualized based on the clinical status, balancing risks and benefits and potential risk for developing these complications among people with T2D.

Non-Traditional Pathways for Platelet Pathophysiology in Diabetes: Implications for Future Therapeutic Targets

Cardiovascular complications remain the leading cause of morbidity and mortality in individuals with diabetes, driven by interlinked metabolic, inflammatory, and thrombotic changes. Hyperglycaemia, insulin resistance/deficiency, dyslipidaemia, and associated oxidative stress have been linked to abnormal platelet function leading to hyperactivity, and thus increasing vascular thrombotic risk. However, emerging evidence suggests platelets also contribute to low-grade inflammation and additionally possess the ability to interact with circulating immune cells, further driving vascular thrombo-inflammatory pathways. This narrative review highlights the role of platelets in inflammatory and immune processes beyond typical thrombotic effects and the impact these mechanisms have on cardiovascular disease in diabetes. We discuss pathways for platelet-induced inflammation and how platelet reprogramming in diabetes contributes to the high cardiovascular risk that characterises this population. Fully understanding the mechanistic pathways for platelet-induced vascular pathology will allow for the development of more effective management strategies that deal with the causes rather than the consequences of platelet function abnormalities in diabetes.

Thrombopoietin Contributes to Enhanced Platelet Activation in Patients with Type 1 Diabetes Mellitus

Atherosclerotic cardiovascular disease is the major cause of morbidity and mortality in patients with type 1 diabetes mellitus (T1DM). Enhanced platelet reactivity is considered a main determinant of the increased atherothrombotic risk of diabetic patients. Thrombopoietin (THPO), a humoral growth factor able to stimulate megakaryocyte proliferation and differentiation, also modulates the response of mature platelets by enhancing both activation and binding to leukocytes in response to different agonists. Increased THPO levels have been reported in different clinical conditions characterized by a generalized pro-thrombotic state, from acute coronary syndromes to sepsis/septic shock, and associated with elevated indices of platelet activation. To investigate the potential contribution of elevated THPO levels in platelet activation in T1DM patients, we studied 28 T1DM patients and 28 healthy subjects. We measured plasma levels of THPO, as well as platelet-leukocyte binding, P-selectin, and THPO receptor (THPOR) platelet expression. The priming activity of plasma from diabetic patients or healthy subjects on platelet–leukocyte binding and the role of THPO on this effect was also studied in vitro. T1DM patients had higher circulating THPO levels and increased platelet–monocyte and platelet–granulocyte binding, as well as platelet P-selectin expression, compared to healthy subjects, whereas platelet expression of THPOR did not differ between the two groups. THPO concentrations correlated with platelet–leukocyte binding, as well as with fasting glucose and Hb1Ac. In vitro, plasma from diabetic patients, but not from healthy subjects, primed platelet–leukocyte binding and platelet P-selectin expression. Blocking THPO biological activity using a specific inhibitor prevented the priming effect induced by plasma from diabetic patients. In conclusion, augmented THPO may enhance platelet activation in patients with T1DM, potentially participating in increasing atherosclerotic risk.

The Effect of Empagliflozin on Platelet Function Profiles in Patients with Stable Coronary Artery Disease in Trinidad: The EFFECT Pilot Study

Introduction

This prospective pharmacodynamic (PD) study aimed to assess the effect of the sodium–glucose cotransporter 2 inhibitor (SGLT2i) empagliflozin on platelet reactivity.

Methods

Patients with stable coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM) (n = 20) who were actively treated with dual antiplatelet therapy (DAPT) of aspirin 81 mg daily and clopidogrel 75 mg daily were recruited. Platelet function was measured with the VerifyNow™ P2Y₁₂ assay (Instrumentation Laboratory, Massachusetts, USA) and assessed before the initiation of and after 10 days of treatment with empagliflozin 25 mg once daily maintenance dose regimen. Results were compared with a paired t test.

Results

The mean P2Y₁₂ reaction units (PRU) on empagliflozin was significantly less than without empagliflozin at baseline (187.35, 95% confidence interval (CI) 155.38–219.32 vs. 217.25, CI 180.60–253.90; p < 0.030). The mean difference in PRU was 29.90 (95% CI 3.17–56.63). No patients experienced any serious adverse events (SAEs).

Conclusions

Significantly attenuated platelet reactivity was observed on empagliflozin as compared to without empagliflozin. This dedicated pharmacodynamic study could be clinically pertinent for Trinidadian patients with stable CAD and T2DM on DAPT. Further studies are required to confirm these exploratory findings. (Funded by the University of the West Indies, St. Augustine; EFFECT).

Clinical Trial Registration

ClinicalTrials.gov number NCT04342819.

An investigation into the pleiotropic activity of metformin. A glimpse of haemostasis

The most characteristic features of type 2 diabetes mellitus (T2DM) are hyperglycaemia and insulin resistance, however, patients with T2DM are at higher risk of cardiovascular disease (CVD) and atherosclerosis. Diabetes, frequently related to metabolic and vascular impairments, is also associated with thrombosis, increased blood coagulation and an imbalance between coagulation and fibrinolysis. Metformin is the most often used oral glucose-lowering agent; its beneficial properties include lowering insulin resistance, weight reduction and cardioprotection. Available data suggest that the advantageous properties of metformin stem from its favourable effects on endothelium, and anti-oxidative and anti-inflammatory properties. This paper reviews the favourable impact of metformin on endothelial function, with particular emphasis on the release of endogenous molecules modulating the state of the vascular endothelium and coagulation. It also summarizes the present knowledge on the influence of metformin on platelet activity and plasma haemostasis, including clot formation, stabilization and fibrinolysis. Its findings confirm that metformin should constitute first line therapy of T2DM subjects; however, more comprehensive methodical studies are required to discover the full potential of this drug.

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.

The Main Determinants of Diabetes Mellitus Vascular Complications: Endothelial Dysfunction and Platelet Hyperaggregation

Diabetes mellitus is a common disease that affects 3–5% of the general population in Italy. In some countries of northern Europe or in North America, it can even affect 6–8% of the population. Of great concern is that the number of cases of diabetes is constantly increasing, probably due to the increase in obesity and the sedentary nature of the population. According to the World Health Organization, in the year 2030 there will be 360 million people with diabetes, compared to 170 million in 2000. This has important repercussions on the lives of patients and their families, and on health systems that offer assistance to patients. In this review, we try to describe in an organized way the pathophysiological continuity between diabetes mellitus, endothelial dysfunction, and platelet hyperaggregation, highlighting the main molecular mechanisms involved and the interconnections.

Diabetes mellitus: A review of some of the prognostic markers of response to treatment and management

Background: The WHO defined ‘diabetes mellitus’ (DM) as a metabolic disorder characterised by chronic hyperglycaemia with disturbances of carbohydrate, fat and protein metabolism resulting from the defect in insulin secretion, or inaction, or both. When not identified early and controlled, acute and chronic life-threatening consequences may result. Identifying DM early for treatment and management, as well as clinically monitoring recovery and improvement during treatment, involves the assessments of biomarkers. The types, choice, sensitivity and descriptive information trends of these biomarkers are very important. Aim: Some prognostic biomarkers and parameters that this review identified include glycated haemoglobin, white blood cells, mean neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, total leukocytes and neutrophils, plasma low-density lipoprotein, high-density lipoprotein and very low-density lipoprotein, platelet, fibrinogen, D-dimer and C-reactive proteins. Results: These parameters display increases in DM, while red blood cell, haemoglobin concentration, activated partial thromboplastin time, prothrombin time and partial thromboplastin time are decreased. Conclusion: With sound knowledge of the variations of these markers and parameters, observed reversal during treatment and management of DM and its complications can be better monitored, and guided decisions can be made.

Impact of Glycemic Control on Efficacy of Clopidogrel in Transient Ischemic Attack or Minor Stroke Patients With CYP2C19 Genetic Variants

BACKGROUND AND PURPOSE

Dysglycemia may influence the predictive value of CYP2C19 loss-of-function allele for clinical efficacy of antiplatelet drug, but the role of glycated albumin (GA) remains unclear in patients with stroke on antiplatelet drugs.

METHODS

The CHANCE trial (Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events) included 2933 patients who had GA levels and CYP2C19 genotyping. Cox proportional hazards model was used to assess the interaction between CYP2C19 loss-of-function allele (*2, *3) carrier status and the effect of antiplatelet therapy based on their GA levels.

RESULTS

There was significant interaction between carrier status and antiplatelet therapy regimen on the risk of recurrent stroke (P=0.03) in patients with GA levels of ≤15.5%, but not in those with GA levels of >15.5% (P=0.48). Only in noncarriers with low GA levels, dual-antiplatelet therapy reduced stroke recurrence (3.5%) compared with those on aspirin alone (14.7%; hazard ratio, 0.23; 95% confidence interval, 0.10-0.49; P<0.001). Similar effects were observed when examined the combined vascular event or ischemic stroke. No significant difference in bleeding was found among groups.

CONCLUSIONS

In patients with minor stroke or high-risk transient ischemic attack, clopidogrel-aspirin when compared with aspirin alone reduced stroke recurrence only in noncarriers of CYP2C19 loss-of-function allele and normal GA levels.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00979589.

Glycemic Control in Coronary Revascularization

OPINION STATEMENT

Hyperglycemia in the setting of coronary revascularization is associated with increased adverse cardiovascular events in patients with or without diabetes mellitus. Data suggest that acute peri-procedural hyperglycemia causes an increase in inflammation, platelet activity, and endothelial dysfunction and is associated with plaque instability and infarct size. While peri-procedural blood glucose level is an independent predictor of adverse outcomes in patients undergoing coronary revascularization, treatment strategies remain uncertain. Randomized clinical trials of glucose-insulin-potassium infusions have consistently shown no benefit, while those comparing insulin therapy versus standard of care have demonstrated mixed results, likely due to the failure to reach euglycemia with these strategies. Although no glucose-lowering agent has been shown to be superior in peri-procedural glycemic control, the continuation of clinically prescribed long-acting glucose-lowering medications in patients with diabetes mellitus prior to coronary angiography and possible percutaneous coronary intervention may be the simplest and most effective approach to maintain euglycemia and decrease the associated increase in inflammation and platelet activity. However, alternative strategies such as therapies targeted at the underlying mechanism of harm (e.g., more potent anti-platelet therapy, anti-inflammatory therapy) should also be considered and warrant further investigation.

Effects of oral hypoglycemic agents on platelet function

Platelet dysfunction plays a role in diabetic macrovascular complications. Several studies have assessed the effect of oral hypoglycemic agents (OHAs) on platelet function. Data from both in vivo and in vitro studies show a favorable effect for most of the traditional glucose-lowering therapies, while evidence is limited for the newer ones. Metformin, sulfonylureas, glitazones and acarbose exert a favorable effect on platelet function. Among incretin therapies, only sitagliptin has so far been demonstrated to have a beneficial effect on platelet aggregation. More in vivo and in vitro evidence is required to increase our knowledge on any potential beneficial effects of OHAs on platelet function. Any such effect may have implications for the reduction of cardiovascular risk in type 2 diabetes mellitus.

WITHDRAWN: Targeting intensive glycaemic control versus targeting conventional glycaemic control for type 2 diabetes mellitus

The Cochrane Metabolic and Endocrine Disorders Group withdrew this review as of Issue 7, 2015 because the involvement of two authors (C Hemmingsen and SS Lund) being employed in pharmaceutical companies. The authors of the review and the Cochrane Metabolic and Endocrine Disorders Group did not find that this was a breach of the rules of the Cochrane Collaboration at the time when it was published. However, after the publication of the review, the Cochrane Collaboration requested withdrawal of the review due to the employment of the two authors. A new protocol for a review to cover this topic will be published. This will have a new title and a markedly improved protocol fulfilling new and important developments and standards within the Cochrane Collaboration as well as an improved inclusion and search strategy making it necessary to embark on a completely new review project.

The editorial group responsible for this previously published document have withdrawn it from publication.

High-risk type-2 diabetes mellitus patients, without prior ischemic events, have normal blood platelet functionality profiles: a cross-sectional study

Background

Patients with type 2 diabetes mellitus (DM) display a predisposition for vascular disease. Platelets taken from vasculopathic diabetic patients, show enhanced stimuli-induced activation and aggregation responses. Aspirin remains the cornerstone antiplatelet agent for secondary prevention of vascular complications among diabetic patients, yet evidence of its efficacy and safety in primary prevention are conflicting. Our aim was to assess whether high risk diabetic patients, without previous ischemic events, have abnormal platelet functionality profiles.

Methods

The study included 82 diabetic patients and 86 matched non-diabetic patients without prior ischemic events nor treatment with anti-platelet medications. Blood samples were analyzed for platelet markers of activation, turnover and leukocyte-platelet interactions.

Results

Our final analysis included 122 males (74 %), with a mean age of 61 years. Mean platelet volume (MPV) was similar between the diabetic patients and controls (9.2 fL for both). Following activation, PAC-1 binding and P-selectin expression were found comparable between the diabetic patients and controls (83 % versus 81 % and 76 % versus 74 %, respectively). Leukocyte-platelet aggregates (LPAs) were similar between the diabetic patients and controls (18 % versus 17 %, respectively). Neutrophil-platelet aggregates (NPAs) and monocyte-platelet aggregates (MPAs) were also found similar in the diabetic patients and controls. Elevated fasting plasma glucose was associated with increased LPAs rates.

Conclusions

High risk type-2 diabetes mellitus patients, without prior ischemic events, have normal blood platelet functionality profiles.

Decreased platelet aggregation by shear stress-stimulated endothelial cells in vitro: description of a method and first results in diabetes

The interaction between platelets and endothelium in vivo is a complex phenomenon. Our aim was to develop an in vitro system that mimics the in vivo environment and investigate platelet function in a common pathological condition. Human umbilical vein endothelial cells were used and platelets from 28 type 2 diabetes patients were studied under shear stress conditions. Mean coefficient of variation of platelet aggregation was 10% in dynamic conditions in the presence of endothelium. Endothelial cells increased the concentration of inductor needed to achieve 50% platelet aggregation to adenosine diphosphate from 2.6 ± 1.3 in static conditions to 3.7 ± 1.3 µM in dynamic conditions. A similar pattern was observed when collagen was used for platelet activation. Incubation of endothelium with a nitric oxide inhibitor abolished this effect, indicating platelet inhibitory effect of endothelial cells is nitric oxide mediated. Platelet reactivity of healthy controls was less influenced by the presence of endothelial cells and displayed reduced basal platelet reactivity compared with platelets from diabetes patients. We show that platelet aggregation in diabetes as commonly reported in vitro may not fully reflect the in vivo pathophysiological process. Future studies are warranted to investigate other pathological conditions and analyse the effects of antiplatelet agents using this system.

Prediabetes and short-term outcomes in nondiabetic patients after acute ST-elevation myocardial infarction

OBJECTIVES

A prediabetic state is defined as the time period before the development of symptomatic diabetes. Limited evidence is available for evaluating the correlation between prediabetes and short-term outcomes in nondiabetic patients with ST-elevation of myocardial infarction (STEMI).

METHODS

4,787 nondiabetic patients with a diagnosis of STEMI based on typical onset of chest pain within 12 h were enrolled. Patients were followed up for 7 and 30 days after hospital admission. According to the 2013 Standards of Medical Care in Diabetes, the study population was stratified into three groups: normal, prediabetic and newly diagnosed diabetic patients. The primary outcomes of our study were all-cause mortality and major adverse cardiac events (MACE) on days 7 day and 30.

RESULTS

The proportions of patients with prediabetes and newly diagnosed diabetes were 31.1 and 19.2%, respectively. Rates of 7- and 30-day mortality and MACE were similar among the different HbA1c groups. Multivariable Cox regression analysis showed that compared with normal glucose metabolism, prediabetes (hazard ratio, HR, 1.003; 95% CI, 0.865-1.165) and newly diagnosed diabetes (HR, 0.887; 95% CI, 0.739-1.064) were not correlated with 30-day MACE. However, admission glucose was an independent predictor of short-term MACE (HR, 1.031; 95% CI, 1.017-1.046).

CONCLUSIONS

In nondiabetic patients after STEMI, the incidence of latent diabetes mellitus was increased. Newly diagnosed diabetes and prediabetes were not correlated with short-term outcome in nondiabetic patients with STEMI, yet admission glucose level was an independent predictor of short-term MACE. To reduce the incidence of short-term MACE after STEMI, more attention should be paid to the control of increased glucose levels and intrinsic stress states.

Targeting intensive glycaemic control versus targeting conventional glycaemic control for type 2 diabetes mellitus

BACKGROUND

Patients with type 2 diabetes mellitus (T2D) have an increased risk of cardiovascular disease and mortality compared to the background population. Observational studies report an association between reduced blood glucose and reduced risk of both micro- and macrovascular complications in patients with T2D. Our previous systematic review of intensive glycaemic control versus conventional glycaemic control was based on 20 randomised clinical trials that randomised 29 ,986 participants with T2D. We now report our updated review.

OBJECTIVES

To assess the effects of targeted intensive glycaemic control compared with conventional glycaemic control in patients with T2D.

SEARCH METHODS

Trials were obtained from searches of The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, LILACS, and CINAHL (all until December 2012).

SELECTION CRITERIA

We included randomised clinical trials that prespecified targets of intensive glycaemic control versus conventional glycaemic control targets in adults with T2D.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias and extracted data. Dichotomous outcomes were assessed by risk ratios (RR) and 95% confidence intervals (CI). Health-related quality of life and costs of intervention were assessed with standardized mean differences (SMD) and 95% Cl.

MAIN RESULTS

Twenty-eight trials with 34,912 T2D participants randomised 18,717 participants to intensive glycaemic control versus 16,195 participants to conventional glycaemic control. Only two trials had low risk of bias on all risk of bias domains assessed. The duration of the intervention ranged from three days to 12.5 years. The number of participants in the included trials ranged from 20 to 11,140. There were no statistically significant differences between targeting intensive versus conventional glycaemic control for all-cause mortality (RR 1.00, 95% CI 0.92 to 1.08; 34,325 participants, 24 trials) or cardiovascular mortality (RR 1.06, 95% CI 0.94 to 1.21; 34,177 participants, 22 trials). Trial sequential analysis showed that a 10% relative risk reduction could be refuted for all-cause mortality. Targeting intensive glycaemic control did not show a statistically significant effect on the risks of macrovascular complications as a composite outcome in the random-effects model, but decreased the risks in the fixed-effect model (random RR 0.91, 95% CI 0.82 to 1.02; and fixed RR 0.93, 95% CI 0.87 to 0.99; P = 0.02; 32,846 participants, 14 trials). Targeting intensive versus conventional glycaemic control seemed to reduce the risks of non-fatal myocardial infarction (RR 0.87, 95% CI 0.77 to 0.98; P = 0.02; 30,417 participants, 14 trials), amputation of a lower extremity (RR 0.65, 95% CI 0.45 to 0.94; P = 0.02; 11,200 participants, 11 trials), as well as the risk of developing a composite outcome of microvascular diseases (RR 0.88, 95% CI 0.82 to 0.95; P = 0.0008; 25,927 participants, 6 trials), nephropathy (RR 0.75, 95% CI 0.59 to 0.95; P = 0.02; 28,096 participants, 11 trials), retinopathy (RR 0.79, 95% CI 0.68 to 0.92; P = 0.002; 10,300 participants, 9 trials), and the risk of retinal photocoagulation (RR 0.77, 95% CI 0.61 to 0.97; P = 0.03; 11,212 participants, 8 trials). No statistically significant effect of targeting intensive glucose control could be shown on non-fatal stroke, cardiac revascularization, or peripheral revascularization. Trial sequential analyses did not confirm a reduction of the risk of non-fatal myocardial infarction but confirmed a 10% relative risk reduction in favour of intensive glycaemic control on the composite outcome of microvascular diseases. For the remaining microvascular outcomes, trial sequential analyses could not establish firm evidence for a 10% relative risk reduction. Targeting intensive glycaemic control significantly increased the risk of mild hypoglycaemia, but substantial heterogeneity was present; severe hypoglycaemia (RR 2.18, 95% CI 1.53 to 3.11; 28,794 participants, 12 trials); and serious adverse events (RR 1.06, 95% CI 1.02 to 1.10; P = 0.007; 24,280 participants, 11 trials). Trial sequential analysis for a 10% relative risk increase showed firm evidence for mild hypoglycaemia and serious adverse events and a 30% relative risk increase for severe hypoglycaemia when targeting intensive versus conventional glycaemic control. Overall health-related quality of life, as well as the mental and the physical components of health-related quality of life did not show any statistical significant differences.

AUTHORS' CONCLUSIONS

Although we have been able to expand the number of participants by 16% in this update, we still find paucity of data on outcomes and the bias risk of the trials was mostly considered high. Targeting intensive glycaemic control compared with conventional glycaemic control did not show significant differences for all-cause mortality and cardiovascular mortality. Targeting intensive glycaemic control seemed to reduce the risk of microvascular complications, if we disregard the risks of bias, but increases the risk of hypoglycaemia and serious adverse events.

Mean platelet volume in Type 2 diabetes mellitus

CONTEXT

Diabetes mellitus is a global pandemic. The increased platelet activity may play a role in the development of vascular complications of this metabolic disorder. The mean platelet volume (MPV) is an indicator of the average size and activity of platelets. Larger platelets are younger and exhibit more activity.

AIMS

to determine the MPV in diabetics compared to nondiabetics, to see if there is a difference in MPV between diabetics with and without vascular complications, and to determine the correlation of MPV with fasting blood glucose, glycosylated hemoglobin (HbA1c), body-mass index, and duration of diabetes in the diabetic patients.

MATERIALS AND METHODS

platelet counts and MPV were measured in 300 Type 2 diabetic patients and 300 nondiabetic subjects using an automated blood cell counter. The blood glucose levels and HbA1c levels were also measured. Statistical evaluation was performed by SPSS using Student's t test and Pearson correlation tests.

RESULTS

the mean platelet counts and MPV were higher in diabetics compared to the nondiabetic subjects [277.46 ± 81 X 109/l vs. 269.79 ± 78 X 109/l (P= 0.256)], 8.29 ± 0.74 fl versus 7.47 ± 0.73 fl (P= 0.001), respectively. MPV showed a strong positive correlation with fasting blood glucose, postprandial glucose and HbA1C levels (P=0.001).

CONCLUSIONS

our results showed significantly higher MPV in diabetic patients than in the nondiabetic subjects. This indicates that elevated MPV could be either the cause for or due to the effect of the vascular complications. Hence, platelets may play a role and MPV can be used as a simple parameter to assess the vascular events in diabetes.

Perioperative glycaemic control for diabetic patients undergoing surgery

BACKGROUND

Patients with diabetes mellitus are at increased risk of postoperative complications. Data from randomised clinical trials and meta-analyses point to a potential benefit of intensive glycaemic control, targeting near-normal blood glucose, in patients with hyperglycaemia (with and without diabetes mellitus) being submitted to surgical procedures. However, there is limited evidence concerning this question in patients with diabetes mellitus undergoing surgery.

OBJECTIVES

To assess the effects of perioperative glycaemic control for diabetic patients undergoing surgery.

SEARCH METHODS

Trials were obtained from searches of The Cochrane Library, MEDLINE, EMBASE, LILACS, CINAHL and ISIS (all up to February 2012).

SELECTION CRITERIA

We included randomised controlled clinical trials that prespecified different targets of perioperative glycaemic control (intensive versus conventional or standard care)

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. We summarised studies using meta-analysis or descriptive methods.

MAIN RESULTS

Twelve trials randomised 694 diabetic participants to intensive control and 709 diabetic participants to conventional glycaemic control. The duration of the intervention ranged from just the duration of the surgical procedure up to 90 days. The number of participants ranged from 13 to 421, and the mean age was 64 years. Comparison of intensive with conventional glycaemic control demonstrated the following results for our predefined primary outcomes: analysis restricted to studies with low or unclear detection or attrition bias for infectious complications showed a risk ratio (RR) of 0.46 (95% confidence interval (CI) 0.18 to 1.18), P = 0.11, 627 participants, eight trials, moderate quality of the evidence (grading of recommendations assessment, development and evaluation - (GRADE)). Evaluation of death from any cause revealed a RR of 1.19 (95% CI 0.89 to 1.59), P = 0.24, 1365 participants, 11 trials, high quality of the evidence (GRADE).On the basis of a posthoc analysis, there is the hypothesis that intensive glycaemic control may increase the risk of hypoglycaemic episodes if longer-term outcome measures are analysed (RR 6.92, 95% CI 2.04 to 23.41), P = 0.002, 724 patients, three trials, low quality of the evidence (GRADE). Analysis of our predefined secondary outcomes revealed the following findings: cardiovascular events had a RR of 1.03 (95% CI 0.21 to 5.13), P = 0.97, 682 participants, six trials, moderate quality of the evidence (GRADE) when comparing the two treatment modalities; and renal failure also did not show significant differences between intensive and regular glucose control (RR 0.61, 95% CI 0.34 to 1.08), P = 0.09, 434 participants, two trials, moderate quality of the evidence (GRADE). We did not meta-analyse length of hospital stay and intensive care unit (ICU) stay due to substantial unexplained heterogeneity. Mean differences between intensive and regular glucose control groups ranged from -1.7 days to 2.1 days for ICU stay and between -8 days to 3.7 days for hospital stay (moderate quality of the evidence (GRADE)). One trial assessed health-related quality of life in 12/37 (32.4%) of participants in the intervention group and 13/44 (29.5%) of participants in the control group, and did not show an important difference (low quality of the evidence (GRADE)) in the measured physical health composite score of the short-form 12-item health survey (SF-12). None of the trials examined the effects of the interventions in terms of costs.

AUTHORS' CONCLUSIONS

The included trials did not demonstrate significant differences for most of the outcomes when targeting intensive perioperative glycaemic control compared with conventional glycaemic control in patients with diabetes mellitus. However, posthoc analysis indicated that intensive glycaemic control was associated with an increased number of patients experiencing hypoglycaemic episodes. Intensive glycaemic control protocols with near-normal blood glucose targets for patients with diabetes mellitus undergoing surgical procedures are currently not supported by an adequate scientific basis. We suggest that insulin treatment regimens, patient- and health-system relevant outcomes, and time points for outcome measures should be defined in a thorough and uniform way in future studies.

Glycosylated hemoglobin and outcomes in diabetic patients with acute myocardial infarction after successful revascularization with stent placement: findings from the guthrie health off-label stent (GHOST) investigators

OBJECTIVE

We evaluated the influence of glycemic control on cardiovascular outcomes in diabetic patients with acute myocardial infarction (AMI) who underwent successful percutaneous coronary intervention (PCI) with stent placement.

BACKGROUND

In patients presenting with AMI, diabetic status confers adverse cardiovascular outcomes after PCI. However, the influence of glycemic control on outcomes after successful PCI is less well studied.

METHODS

We examined 231 consecutive diabetes mellitus (DM) patients with AMI who underwent successful primary PCI and had evaluation of glycosylated hemoglobin (HbA1c) from 30 days before to 90 days after AMI. Patients were categorized in 2 groups, controlled DM with HbA1c ≤ 7.0 (N = 83, 36%) and uncontrolled DM with HbA1c > 7.0 (N = 148, 64%). We assessed 12-month cardiovascular outcomes in study groups.

RESULTS

Uncontrolled diabetics were younger, tended to be less hypertensive, and had higher baseline glomerular filtration rate and final vessel diameter compared to controlled diabetics. Uncontrolled DM patients had similar major adverse cardiovascular events (MACE; composite of all-cause death, MI, target vessel revascularization [TVR], and stent thrombosis [ST]; 20% vs. 30%, log-rank P = 0.54), death (8.8% vs. 12%, P = 0.40), MI (8.8% vs. 9.6%, P = 0.76), TVR (9.5% vs. 8.4%, P = 0.95), and ST (3.4% vs. 4.8%, P = 0.54) as the controlled diabetics. In Cox regression analysis, after adjustment for baseline differences, glycemic control had no independent influence on study outcomes.

CONCLUSION

Glycemic control, determined by HbA1c, does not seem to influence cardiovascular outcomes in diabetic patients with AMI after successful stent placement.

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.

Targeting intensive glycaemic control versus targeting conventional glycaemic control for type 2 diabetes mellitus

BACKGROUND

Patients with type 2 diabetes mellitus (T2D) exhibit an increased risk of cardiovascular disease and mortality compared to the background population. Observational studies report a relationship between reduced blood glucose and reduced risk of both micro- and macrovascular complications in patients with T2D.

OBJECTIVES

To assess the effects of targeting intensive versus conventional glycaemic control in T2D patients.

SEARCH STRATEGY

Trials were obtained from searches of CENTRAL (The Cochrane Library), MEDLINE, EMBASE, Science Citation Index Expanded, LILACS, and CINAHL (until December 2010).

SELECTION CRITERIA

We included randomised clinical trials that prespecified different targets of glycaemic control in adults with T2D.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias and extracted data. Dichotomous outcomes were assessed by risk ratios (RR) and 95% confidence intervals (CI).

MAIN RESULTS

Twenty trials randomised 16,106 T2D participants to intensive control and 13,880 T2D participants to conventional glycaemic control. The mean age of the participants was 62.1 years. The duration of the intervention ranged from three days to 12.5 years. The number of participants in the included trials ranged from 20 to 11,140. There was no significant difference between targeting intensive and conventional glycaemic control for all-cause mortality (RR 1.01, 95% CI 0.90 to 1.13; 29,731 participants, 18 trials) or cardiovascular mortality (RR 1.06, 95% CI 0.90 to 1.26; 29,731 participants, 18 trials). Trial sequential analysis (TSA) showed that a 10% RR reduction could be refuted for all-cause mortality. Targeting intensive glycaemic control did not show a significant effect on the risk of non-fatal myocardial infarction in the random-effects model but decreased the risk in the fixed-effect model (RR 0.86, 95% CI 0.78 to 0.96; P = 0.006; 29,174 participants, 12 trials). Targeting intensive glycaemic control reduced the risk of amputation (RR 0.64, 95% CI 0.43 to 0.95; P = 0.03; 6960 participants, 8 trials), the composite risk of microvascular disease (RR 0.89, 95% CI 0.83 to 0.95; P = 0.0006; 25,760 participants, 4 trials), retinopathy (RR 0.79, 95% CI 0.68 to 0.92; P = 0.002; 10,986 participants, 8 trials), retinal photocoagulation (RR 0.77, 95% CI 0.61 to 0.97; P = 0.03; 11,142 participants, 7 trials), and nephropathy (RR 0.78, 95% CI 0.61 to 0.99; P = 0.04; 27,929 participants, 9 trials). The risks of both mild and severe hypoglycaemia were increased with targeting intensive glycaemic control but substantial heterogeneity was present. The definition of severe hypoglycaemia varied among the included trials; severe hypoglycaemia was reported in 12 trials that included 28,127 participants. TSA showed that firm evidence was reached for a 30% RR increase in severe hypoglycaemic when targeting intensive glycaemic control. Subgroup analysis of trials exclusively dealing with glycaemic control in usual care settings showed a significant effect in favour of targeting intensive glycaemic control for non-fatal myocardial infarction. However, TSA showed more trials are needed before firm evidence is established.

AUTHORS' CONCLUSIONS

The included trials did not show significant differences for all-cause mortality and cardiovascular mortality when targeting intensive glycaemic control compared with conventional glycaemic control. Targeting intensive glycaemic control reduced the risk of microvascular complications while increasing the risk of hypoglycaemia. Furthermore, intensive glycaemic control might reduce the risk of non-fatal myocardial infarction in trials exclusively dealing with glycaemic control in usual care settings.

The fixed combination of pioglitazone and metformin improves biomarkers of platelet function and chronic inflammation in type 2 diabetes patients: results from the PIOfix study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is characterized by a proinflammatory and procoagulant condition. This study investigates the impact of a pioglitazone plus metformin therapy on biomarkers of inflammation and platelet activation in comparison to a treatment with glimepiride plus metformin.

METHODS

The study was designed as a multicenter, randomized, double-blinded two-arm trial. Patients with T2DM and dyslipidemia under metformin monotherapy with hemoglobin A1c value between 6.5% and 9.0% were eligible for trial participation. Blood was drawn at baseline and after 24 weeks of treatment from patients of five centers. Markers of inflammation and thrombocyte function (soluble CD40 ligand, thromboxane, vWillebrand factor, adhesion molecules, clotting reaction) were evaluated subsequently in a central laboratory.

RESULTS

A total of 46 patients were included in the final analyses. Mean (± standard deviation) age was 58.5 ± 9.0 years (13 women, 33 men; disease duration 6.3 ± 5.0 years; body mass index 32.0 ± 4.8 kg/m(2)). A total of 25 patients were treated with pioglitazone plus metformin, and 21 patients were in the glimepiride arm. There was a significant decline of E-selectin (-3.7 ± 4.8 ng/ml, p < .001 versus baseline), vWillebrand factor (-19.5 ± 32.0%, p < .05), and high-sensitivity C-reactive protein concentrations (-1.08 ± 0.91 mg/liter, p < .05) in the metformin + pioglitazone arm only (metformin + glimepiride, -0.5 ± 3.4 ng/ml, +1.4 ± 33.2%, + 0.08 ± 0.72 mg/liter, respectively, all not significant). Also, all other surrogate markers for platelet function and inflammation showed slight improvements in the metformin + pioglitazone arm but not in the metformin + glimepiride arm.

CONCLUSIONS

The fixed metformin + pioglitazone combination treatment showed an overall improvement of laboratory surrogate markers, indicating improvement of platelet function and of chronic systemic inflammation, which was not seen with metformin + glimepiride.

Platelet function in patients with diabetes mellitus: from a theoretical to a practical perspective

Patients with diabetes mellitus have an increased prevalence of vascular disease. Pathologic thrombosis associated with atherosclerotic plaque rupture is a major cause of morbidity and mortality. Platelets are intimately involved in the initiation and propagation of thrombosis. Evidence suggests that platelets from patients with type 2 diabetes have increased reactivity and baseline activation compared to healthy controls. We review the pathophysiology of platelet hyperreactivity in DM patients and its implications in clinical practice, with particular focus on acute coronary syndromes, percutaneous coronary intervention, and novel antiplatelet agents.

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.

Influence of glycaemic control on platelet bound CD40-CD40L system, P-selectin and soluble CD40 ligand in Type 2 diabetes

AIMS

Type 2 diabetes is a potent cardiovascular risk factor, associated with proinflammatory and prothrombotic processes. The purpose of this study was to investigate whether platelet-bound CD40-CD40L signalling, P-selectin expression and soluble CD40L were increased in patients with diabetes mellitus and can be normalized by improving glycaemic control.

METHODS

Soluble (s) CD40L, platelet surface expression of CD40L, CD40 and P-selectin (CD62P) on platelets were measured by flow cytometry in 71 patients with Type 2 diabetes mellitus and 37 healthy volunteers. In addition, the relationship of HbA1c to CD40-CD40L and P-selectin expression was determined in a longitudinal follow-up.

RESULTS

In patients with Type 2 diabetes, platelet membrane CD40 expression (Type 2 diabetes 3.1+/-0.61 vs. controls 2.5+/-0.85 mean fluorescence intensity; P=0.001), platelet-bound CD40L (1.2+/-0.32 vs. 1.1+/-0.14; P=0.034) as well as surface expression of CD62P (0.66+/-0.19 vs. 0.57+/-0.12; P=0.007) were higher than in control subjects. Plasma sCD40L values (3.2+/-1.70 vs. 1.8+/-0.50 ng/ml; P<0.001) were also significantly increased in Type 2 diabetes. After improving glycaemic control in patients with initial HbA1c>8.5% (n=15), platelet P-selectin and CD40-CD40L expression decreased significantly by 54.0%, 36.22% and 16.26%, respectively 1 year later.

CONCLUSIONS

Type 2 diabetes is associated with up-regulation of the platelet-bound CD40-CD40L system, platelet hyperactivity (enhanced P-selectin expression) and increased sCD40L levels. Improved glycaemic control, however, does help to correct abnormal platelet activation via down-regulation of CD40-CD40L system and P-selectin expression.

Effect of high glucose levels in human platelet NTPDase and 5'-nucleotidase activities

OBJECTIVES

The objective of this work was to evaluate the effect of different glucose levels on the ATP, ADP and AMP hydrolysis in the platelets of diabetic, hypertensive and diabetic/hypertensive participants.

METHODS

The activities of the enzymes NTPDase (ATP and ADP hydrolysis) and 5'-nucleotidase (AMP hydrolysis), and CD39 expression were analyzed in human blood platelets of diabetic (DM-2), hypertensive (HT) and diabetic/hypertensive (DM-2/HT) patients. To evaluate the interference of glucose and fructose in NTPDase and 5'-nucleotidase activities, experiments were performed with glucose, fructose and mannitol concentrations ranging from 5 to 30 mM in platelet-rich plasma (PRP). Pre-incubation times of 10, 120 min and 24h were used.

RESULTS

NTPDase and 5'-nucleotidase activities increased with increasing glucose and fructose concentrations (P<0.001) and the different times of pre-incubation did not interfere in ectonucleotidases activities (P>0.5). NTPDase and 5'-nucleotidase activities demonstrated a positive correlation between serum glucose levels and ATP and ADP hydrolysis in DM-2 and DM-2/HT patients. CD39 expression demonstrated that DM-2, HT and DM-2/HT groups presented a significant increase when compared to the control group (P<0.004).

CONCLUSION

The hydrolysis of adenine nucleotides is enhanced in platelets of patients with diabetes and hypertension. We observed that an increasing glucose concentration had a direct effect on ATP, ADP and AMP hydrolysis. Furthermore, CD39 expression was enhanced in all patients groups, indicating that these enzyme activities are related with diabetes and hypertension.

Review of the pleiotropic effects of peroxisome proliferator-activated receptor gamma agonists on platelet function

The primary target receptor for thiazolidinediones (TZDs) or peroxisome proliferator-activated receptor gamma (PPARgamma) agonists is a transcription factor in the nucleus of adipocytes and other metabolically active cells, where they improve insulin sensitivity and glucose utilization. TZDs are also able to modify gene expression in macrophages, smooth muscle cells, and endothelial cells. Although PPARgamma is considered to be a nuclear receptor, enucleate platelets also highly express this receptor. The aim of this review is to present the current understanding of a direct or indirect effect of TZDs on platelet function. By means of a comprehensive literature search (January 1990-June 2006), publications were obtained that contained specific information about in vitro and in vivo effects of TZDs on platelet function. The effects were studied for different risk biochemical markers, i.e., proteins found to be elevated in the state of procoagulant inflammation and endothelial dysfunction. Improvement of platelet function was reported for all TZDs-troglitazone, pioglitazone, and rosiglitazone. The described effects included reduction of platelet aggregation, suppression of thrombin-induced protein kinase C-alpha and -beta activation, decrease in plasma P-selectin and platelet P-selectin expression, increase in nitric oxide production, inhibition of the Rho/Rho kinase pathway, and inhibition of tissue factor- and platelet-activating factor-induced morphological changes in macrophages. These findings appeared in parallel with reduction of the plasma concentrations of pro-inflammatory risk markers. TZDs seem to have a direct pleiotropic positive influence on platelet function and coagulation and may be helpful in treating the prothrombotic state observed in patients with type 2 diabetes and metabolic syndrome.