Low fasting glucose is associated with enhanced thrombin generation and unfavorable fibrin clot properties in type 2 diabetic patients with high cardiovascular risk

The Cellular and Protein Arms of Coagulation in Diabetes: Established and Potential Targets for the Reduction of Thrombotic Risk

Diabetes is a metabolic condition with a rising global prevalence and is characterised by abnormally high blood glucose levels. Cardiovascular disease (CVD) accounts for the majority of deaths in diabetes and, despite improvements in therapy, mortality and hospitalisations in this cohort remain disproportionally higher compared to individuals with normal glucose metabolism. One mechanism for increased CVD risk is enhanced thrombosis potential, due to altered function of the cellular and acellular arms of coagulation. Different mechanisms have been identified that mediate disordered blood clot formation and breakdown in diabetes, including dysglycaemia, insulin resistance, and metabolic co-morbidities. Collectively, these induce platelet/endothelial dysfunction and impair the fibrinolytic process, thus creating a prothrombotic milieu. Despite these abnormalities, current antithrombotic therapies are largely similar in diabetes compared to those without this condition, which explains the high proportion of patients experiencing treatment failure while also displaying an increased risk of bleeding events. In this narrative review, we aimed to summarise the physiological functioning of haemostasis followed by the pathological effects of diabetes mellitus on platelets and the fibrin network. Moreover, we carefully reviewed the literature to describe the current and future therapeutic targets to lower the thrombosis risk and improve vascular outcomes in diabetes.

Effects of Hypoglycemia on Cardiovascular Function in Patients with Diabetes

Hypoglycemia is common in patients with type 1 and type 2 diabetes (T1D, T2D), treated with insulin or sulfonylureas, and has multiple short- and long-term clinical implications. Whether acute or recurrent, hypoglycemia significantly affects the cardiovascular system with the potential to cause cardiovascular dysfunction. Several pathophysiological mechanisms have been proposed linking hypoglycemia to increased cardiovascular risk, including hemodynamic changes, myocardial ischemia, abnormal cardiac repolarization, cardiac arrhythmias, prothrombotic and proinflammatory effects, and induction of oxidative stress. Hypoglycemia-induced changes can promote the development of endothelial dysfunction, which is an early marker of atherosclerosis. Although data from clinical trials and real-world studies suggest an association between hypoglycemia and cardiovascular events in patients with diabetes, it remains uncertain whether this association is causal. New therapeutic agents for patients with T2D do not cause hypoglycemia and have cardioprotective benefits, whereas increasing the use of new technologies, such as continuous glucose monitoring devices and insulin pumps, has the potential to reduce hypoglycemia and its adverse cardiovascular outcomes in patients with T1D.

The DNAm levels of CREB5 (cg11301281) were associated with clopidogrel resistance

Purpose

Clopidogrel resistance (CR) is mostly caused by interindividual variability of the platelet inhibition of clopidogrel, which may induce cardiovascular events. The aim of this research was to evaluate whether DNAm levels of CREB5 (cg01534253) are involved in CR among acute coronary syndrome (ACS) patients treated with clopidogrel.

Methods

72 patients(36 CR and 36 non‐CR) who underwent ACS were included in this study. The VerifyNow P2Y12 assay was selected to evaluate residual platelet reactivity, and bisulfite pyrosequencing methods was used to examine DNA methylation levels on cg01534253. Secondly, CREB5 mRNA expression was analyzed via quantitative real‐time PCR. Last, we employed logistic regression to test the interaction between genetic factors of CREB5 methylation and multiple clinical variables in CR patients.

Results

Subunit analysis indicated that for patients whose HbA1c levels were ≥6.5% or whose GLU levels were ≥7 mmol/L, lower methylation of cg01534253 indicated a poorer clopidogrel response. In addition, CREB5 mRNA expression was increased in CR patients with GLU levels ≥7 mmol/L. Moreover, regression analysis indicated that the values of albumin and uric acid were correlated with the incidence of CR.

Conclusions

Our findings were likely to provide fresh understanding for the new mechanism of platelet inhibition failure and promote individualized antiplatelet therapy.

Alteration of circulating platelet-related and diabetes-related microRNAs in individuals with type 2 diabetes mellitus: a stepwise hypoglycaemic clamp study

BACKGROUND

In patients with type 2 diabetes mellitus (T2DM) an association between severe hypoglycaemic episodes and the risk of cardiovascular (CV) morbidity and mortality has been previously established.

METHODS

We aimed to investigate the influence of hypoglycaemia on several diabetes-related and platelet-related miRNAs selected based on bioinformatic analysis and literature search, including hsa-miR-16, hsa-miR-34a, hsa-miR-129-2, hsa-miR-15a, hsa-miR-15b, hsa-miR-106a, miR-223, miR-126. Selected miRNAs were validated by qRT-PCR in 14 patients with T2DM on metformin monotherapy, without established CV disease and antiplatelet therapy during a stepwise hypoglycaemic clamp experiment and a follow-up 7 days after the clamp event. In order to identify which pathways and phenotypes are associated with validated miRNAs we performed target prediction on genes expressed with high confidence in platelets.

RESULTS

Circulating levels of miR-106a-5p, miR-15b, miR-15a, miR-16-5p, miR-223 and miR-126 were increased after euglycaemic clamp followed by hypoglycaemic clamp, each with its distinctive time trend. On the contrary, miR-129-2-3p, miR-92a-3p and miR-34a-3p remained unchanged. MiR-16-5p was negatively correlated with interleukin (IL)-6, intercellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) (p = 0.002, p < 0.001, p = 0.016, respectively), whereas miR-126 was positively correlated with VCAM (p < 0.001). There were negative correlations between miR-16-5p, miR-126 and coagulation factors, including factor VIII and von Willebrand factor (vWF). Among all studied miRNAs, miR-126, miR-129-2-3p and miR-15b showed correlation with platelet function. Bioinformatic analysis of platelet-related targets of analyzed miRNAs showed strong enrichment of IL-2 signaling. We also observed significant enrichment of pathways and diseases related to cancer, CV diseases, hyperglycemia, and neurological diseases.

CONCLUSIONS

Hypoglycaemia can significantly influence the expression of platelet-enriched miRNAs, with a time trend paralleling the time course of platelet activation. This suggests miRNAs could be exploited as biomarkers for platelet activation in response to hypoglycaemia, as they are probably released by platelets upon activation by hypoglycaemic episodes. Should they hold their promise in clinical endpoint studies, platelet-derived miRNAs might become helpful markers of CV risk in subjects with diabetes. Trial registration The study was registered at clinical trials.gov; Impact of Hypoglycaemia in Patients With DIAbetes Mellitus Type 2 on PLATElet Activation (Diaplate), trial number: NCT03460899.

DNase 1 Protects From Increased Thrombin Generation and Venous Thrombosis During Aging: Cross-Sectional Study in Mice and Humans

Background Human aging is associated with increased risk of thrombosis, but the mechanisms are poorly defined. We hypothesized that aging induces peroxide-dependent release of neutrophil extracellular traps that contribute to thrombin generation and thrombosis. Methods and Results We studied C57BL6J mice and littermates of glutathione peroxidase-1 transgenic and wild-type mice at young (4 month) and old (20 month) ages and a healthy cohort of young (18-39 years) or middle-aged/older (50-72 years) humans. In plasma, we measured thrombin generation potential and components of neutrophil extracellular traps (cell-free DNA and citrullinated histone). Aged wild-type mice displayed a significant increase in thrombin generation that was decreased in aged glutathione peroxidase-1 transgenic mice. Both aged wild-type and aged glutathione peroxidase-1 transgenic mice demonstrated similar elevation of plasma cell-free DNA compared with young mice. In contrast, plasma levels of citrullinated histone were not altered with age or genotype. Release of neutrophil extracellular traps from neutrophils in vitro was also similar between young and aged wild-type or glutathione peroxidase-1 transgenic mice. Treatment of plasma or mice with DNase 1 decreased age-associated increases in thrombin generation, and DNase 1 treatment blocked the development of experimental venous thrombi in aged C57BL6J mice. Similarly, thrombin generation potential and plasma cell-free DNA, but not citrullinated histone, were higher in middle-aged/older humans, and treatment of plasma with DNase 1 reversed the increase in thrombin generation. Conclusions We conclude that DNase 1 limits thrombin generation and protects from venous thrombosis during aging, likely by hydrolyzing cell-free DNA.

Association of glycated hemoglobin A1c levels with cardiovascular outcomes in the general population: results from the BiomarCaRE (Biomarker for Cardiovascular Risk Assessment in Europe) consortium

BACKGROUND

Biomarkers may contribute to improved cardiovascular risk estimation. Glycated hemoglobin A1c (HbA1c) is used to monitor the quality of diabetes treatment. Its strength of association with cardiovascular outcomes in the general population remains uncertain. This study aims to assess the association of HbA1c with cardiovascular outcomes in the general population.

METHODS

Data from six prospective population-based cohort studies across Europe comprising 36,180 participants were analyzed. HbA1c was evaluated in conjunction with classical cardiovascular risk factors (CVRFs) for association with cardiovascular mortality, cardiovascular disease (CVD) incidence, and overall mortality in subjects without diabetes (N = 32,496) and with diabetes (N = 3684).

RESULTS

Kaplan-Meier curves showed higher event rates with increasing HbA1c levels (log-rank-test: p < 0.001). Cox regression analysis revealed significant associations between HbA1c (in mmol/mol) in the total study population and the examined outcomes. Thus, a hazard ratio (HR) of 1.16 (95% confidence interval (CI) 1.02-1.31, p = 0.02) for cardiovascular mortality, 1.13 (95% CI 1.03-1.24, p = 0.01) for CVD incidence, and 1.09 (95% CI 1.02-1.17, p = 0.01) for overall mortality was observed per 10 mmol/mol increase in HbA1c. The association with CVD incidence and overall mortality was also observed in study participants without diabetes with increased HbA1c levels (HR 1.12; 95% CI 1.01-1.25, p = 0.04) and HR 1.10; 95% CI 1.01-1.20, p = 0.02) respectively. HbA1c cut-off values of 39.9 mmol/mol (5.8%), 36.6 mmol/mol (5.5%), and 38.8 mmol/mol (5.7%) for cardiovascular mortality, CVD incidence, and overall mortality, showed also an increased risk.

CONCLUSIONS

HbA1c is independently associated with cardiovascular mortality, overall mortality and cardiovascular disease in the general European population. A mostly monotonically increasing relationship was observed between HbA1c levels and outcomes. Elevated HbA1c levels were associated with cardiovascular disease incidence and overall mortality in participants without diabetes underlining the importance of HbA1c levels in the overall population.

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

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

Thrombotic potential during pediatric acute lymphoblastic leukemia induction: Role of cell-free DNA

BACKGROUND

Thromboembolism affects up to 30% of children undergoing treatment for acute lymphoblastic leukemia (ALL). Increased thrombin generation has been reported in ALL, but the mechanisms remain elusive.

OBJECTIVE

We aimed to show that extracellular traps and cell-free DNA (cfDNA) promote thrombin generation in pediatric ALL.

METHODS

In a longitudinal single-center study, we recruited 17 consecutive pediatric ALL patients. Serial blood samples were collected at diagnosis and weekly during the 4-week induction phase of antileukemic chemotherapy. Healthy children (n = 14) and children with deep vein thrombosis (DVT; n = 7) or sepsis (n = 5) were recruited as negative and positive controls, respectively. In plasma, we measured endogenous thrombin generation potential (ETP) and components of extracellular traps, including cfDNA.

RESULTS

In patients with ALL, ETP was increased at baseline and remained significantly elevated throughout the induction therapy. Plasma levels of cfDNA were increased at baseline and during the first 3 weeks of induction therapy. The extent of enhancement of ETP and plasma cfDNA in patients with ALL was similar to that seen in patients with DVT or sepsis. Treatment of plasma with DNase 1 lowered ETP in patients with ALL at each time point but did not affect ETP in healthy controls.

CONCLUSION

We conclude that childhood ALL is associated with a prothrombotic milieu at the time of diagnosis that continues during induction chemotherapy, and cfDNA contributes to increased thrombogenic potential.

Prolonged Prothrombotic Effects of Antecedent Hypoglycemia in Individuals With Type 2 Diabetes

OBJECTIVE

Hypoglycemia has been linked to persistent increases in cardiovascular (CV) mortality in type 2 diabetes after the event. Our aim was to examine acute and downstream effects of hypoglycemia on markers of thrombosis risk and inflammation in type 2 diabetes.

RESEARCH DESIGN AND METHODS

Twelve individuals with type 2 diabetes with no history of CV disease and 11 age- and BMI-matched volunteers without diabetes underwent paired hyperinsulinemic-euglycemic (glucose 6 mmol/L for two 60-min periods) and hypoglycemic (glucose 2.5 mmol/L for two 60-min periods) clamps on separate occasions on day 0. Fibrin clot properties, platelet reactivity, and inflammatory markers were measured at baseline, end of and after recovery from the initial clamp, day 1, and day 7 using validated assays and electron microscopy.

RESULTS

Euglycemic hyperinsulinemia reduced platelet reactivity, decreased fibrin clot density, and improved fibrinolytic efficiency in both groups. Platelet reactivity and aggregation increased during acute hypoglycemia in both groups, resolving at recovery. In type 2 diabetes, clot lysis times and clot maximum absorbance increased up to day 7 (P = 0.002 and 0.001 vs. euglycemia, respectively), but clots from control subjects without diabetes showed limited changes. Fibrin network density increased Δ 1.15 ± 0.28 fibers/μm² at day 7 after the hypoglycemic clamp (P < 0.01 for glycemic arm), whereas fibrinogen and complement C3 increased after hypoglycemia up to day 7 in type 2 diabetes only.

CONCLUSIONS

Antecedent hypoglycemia has acute and persistent prothrombotic effects, lasting at least 7 days, that were enhanced in individuals with type 2 diabetes. These findings identify mechanisms by which hypoglycemia might increase short- and medium-term risk of CV mortality.

Polyhedrocytes in blood clots of type 2 diabetic patients with high cardiovascular risk: association with glycemia, oxidative stress and platelet activation

Background

Little is known about factors that affect the composition of contracted blood clots in specific diseases. We investigated the content of polyhedral erythrocytes (polyhedrocytes) formed in blood clots and its determinants in type 2 diabetes (T2D) patients.

Methods

In 97 patients with long-standing T2D [median HbA_1c, 6.4% (interquartile range 5.9–7.8)], we measured in vitro the composition of blood clots, including a clot area covered by polyhedrocytes using scanning electron microscopy and the erythrocyte compression index (ECI), defined as a ratio of the mean polyhedrocyte area to the mean native erythrocyte area. Moreover, plasma fibrin clot permeability (K_s), clot lysis time (CLT), thrombin generation, oxidative stress [total protein carbonyl (total PC), total antioxidant capacity and thiobarbituric acid reactive substances (TBARS)], and platelet activation markers were determined. The impact of glucose concentration on polyhedrocytes formation was assessed in vitro.

Results

Polyhedrocytes content in contracted clots was positively correlated with glucose (r = 0.24, p = 0.028), glycated hemoglobin (r = 0.40, p = 0.024), total cholesterol (r = 0.22, p = 0.044), TBARS (r = 0.60, p = 0.0027), P-selectin (r = 0.54, p = 0.0078) and platelet factor-4, PF4 (r = 0.59, p = 0.0032), but not with thrombin generation, platelet count, K_s or CLT. Patients who formed more polyhedrocytes (≥ 10th percentile) (n = 83, 85.6%) had higher glucose (+ 15.7%, p = 0.018), fibrinogen (+ 16.6%, p = 0.004), lower red blood cell distribution width (RDW, − 8.8%, p = 0.034), reduced plasma clot density (− 21.8% K_s, p = 0.011) and impaired fibrinolysis (+ 6.5% CLT, p = 0.037) when compared to patients with lesser amount of polyhedrocytes (< 10th percentile). ECI and the content of polyhedrocytes were strongly associated with total PC (r = 0.79, p = 0.036 and r = 0.67, p = 0.0004, respectively). In vitro an increase of glucose concentration by 10 mmol/L was associated with 94% higher polyhedrocytes content (p = 0.033) when compared to the baseline (7.1 mM). After adjustment for age, sex and fibrinogen, multiple regression analysis showed that RDW was the only independent predictor of polyhedrocytes content in T2D (OR = 0.61, 95% CI 0.39–0.92).

Conclusions

Poor glycemic control, together with enhanced platelet activation and oxidative stress, increase the content of polyhedrocytes in blood clots generated in T2D patients.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0789-6) contains supplementary material, which is available to authorized users.

Relationship between polyunsaturated fatty acid composition in serum phospholipids, systemic low-grade inflammation, and glycemic control in patients with type 2 diabetes and atherosclerotic cardiovascular disease

Background

There are inconsistent data about the role of serum phospholipid fatty acid composition in patients with type 2 diabetes (T2DM) and atherosclerotic cardiovascular disease (ASCVD). The aim of the study was to investigate the relationship between serum phospholipid fatty acid composition, systemic low-grade inflammation, and glycemic control in high-risk T2DM patients.

Methods

Seventy-four patients (26% women, mean age 65.6 ± 6.8 years) with T2DM (median diabetes duration 10 years) and documented ASCVD (74 with coronary artery disease, 26 with peripheral arterial disease) were enrolled in the study. Baseline HbA_1c was estimated using turbidimetric inhibition immunoassay. According to the median value of HbA_1c the patients were grouped into those with HbA_1c < 7.0% (< 53 mmol/mol) (n = 38) and those with HbA_1c ≥ 7.0% (≥ 53 mmol/mol) (n = 36). Serum phospholipid fatty acids were measured with gas chromatography.

Results

Patients with HbA_1c ≥ 7.0%, compared with those with HbA_1c < 7.0% had similar composition of saturated and monounsaturated fatty acids in serum phospholipids, but had higher concentrations of linoleic acid (LA) and higher n-6/n-3 polyunsaturated fatty acid (PUFA) ratio as well as lower levels of eicosapentaenoic acid (EPA), total n-3 PUFAs, and the EPA/arachidonic acid ratio. We found that LA (r = 0.25; p = 0.03) and n-6/n-3 PUFA ratio (r = 0.28; p = 0.02) were positively correlated with HbA_1c. Multivariate logistic regression analysis showed that n-6/n-3 PUFA ratio, hsCRP and T2DM duration were independent predictors of worse glycemic control in patients with T2DM and ASCVD.

Conclusions

This study showed that glycemic control in high-risk T2DM patients with ASCVD was significantly associated with unfavorable serum phospholipid n-6/n-3 PUFA ratio and greater systemic inflammation.

Interdisciplinary approach to compensation of hypoglycemia in diabetic patients with chronic heart failure

Diabetes mellitus is a chronic disease requiring lifelong control with hypoglycemic agents that must demonstrate excellent efficacy and safety profiles. In patients taking glucose-lowering drugs, hypoglycemia is a common cause of death associated with arrhythmias, increased thrombus formation, and specific effects of catecholamines due to sympathoadrenal activation. Focus is now shifting from merely glycemic control to multifactorial approach. In the context of individual drugs and classes, this article reviews interdisciplinary strategies evaluating metabolic effects of drugs for treatment of chronic heart failure (CHF) which can mask characteristic hypoglycemia symptoms. Hypoglycemia unawareness and cardiac autonomic neuropathy are discussed. Data suggesting that hypoglycemia modulates immune response are reviewed. The potential role of gut microbiota in improving health of patients with diabetes and CHF is emphasized. Reports stating that nondiabetic CHF patients can have life-threatening hypoglycemia associated with imbalance of thyroid hormones are discussed. Regular glycemic control based on HbA1c measurements and adequate pharmacotherapy remain the priorities in diabetes management. New antihyperglycemic drugs with safer profiles should be preferred in vulnerable CHF patients. Multidrug interactions must be considered. Emerging therapies with reduced hypoglycemia risk, telemedicine, sensor technologies, and genetic testing predicting hypoglycemia risk may help solving the challenges of hypoglycemia in CHF patients with diabetes. Interdisciplinary work may involve cardiologists, diabetologists/endocrinologists, immunologists, gastroenterologists, microbiologists, nutritionists, imaging specialists, geneticists, telemedicine experts, and other relevant specialists. This review emphasizes that systematic knowledge on pathophysiology of hypoglycemia in diabetic patients with CHF is largely lacking and the gaps in our understanding require further discoveries.

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

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

Association between insulin receptor substrate-1 polymorphisms and high platelet reactivity with clopidogrel therapy in coronary artery disease patients with type 2 diabetes mellitus

BACKGROUND

The mechanisms leading to the high on-treatment platelet reactivity in diabetes patients are not fully elucidated. The genetic factors may be associated with the diminished antiplatelet efficacy of dual antiplatelet therapy. We investigated the possible association between insulin receptor substrate-1 (IRS-1) polymorphisms and high platelet reactivity in coronary artery disease (CAD) patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 674 CAD patients with T2DM were enrolled in this study. Platelet aggregation and platelet activation were assessed with light transmission aggregometry and flow cytometry analysis, respectively. Participants were divided into high platelet reactivity (HPR) group and non-HPR group according to their maximal platelet aggregation. Genotypes were identified by polymerase chain reaction and direct sequencing of genomic DNA. The association between IRS-1 genetic variants and platelet function was assessed.

RESULTS

There were 233 participants in the HPR group and 441 participants in the non-HPR group. G allele frequencies of rs13431554 were 27.7 % for the HPR group and 18.6 % for the non-HPR group (p < 0.001). Adenosine diphosphate and arachidonic acid induced platelet aggregation were significantly higher in G allele carriers compared with non-carriers (56.8 ± 16.2 vs 52.0 ± 17.9 %, p < 0.01, 28.9 ± 18.6 vs 25.2 ± 17.8 %, p < 0.01, respectively). We observed that P-selectin expression and PAC-1 binding were higher in G allele carriers compared with non-carriers (40.8 ± 12.4 vs 36.2 ± 13.8, p = 0.01; 43.7 ± 15.9 vs 38.7 ± 19.9, p = 0.03, respectively).

CONCLUSION

The G allele of rs13431554 in the IRS-1 gene was associated with a hyperreactive platelet phenotype in the CAD patients with T2DM.

The Impact of Hypoglycemia on the Cardiovascular System: Physiology and Pathophysiology

Intensive glycemic control may increase cardiovascular (CV) risk and mortality due to hypoglycemia. The pathophysiology of glucose counter-regulation in patients with type 1 or type 2 diabetes for over 15 years is characterized by impairment of the defense mechanisms against hypoglycemia. Hypoglycemia causes pronounced physiological and pathophysiological effects on the CV system as consequences of autonomic system activation and counter regulatory hormones release. These effects provoke a series of hemodynamic changes that include an increase in heart rate and peripheral systolic blood pressure, a decrease in central blood pressure, reduced peripheral arterial resistance, and increased myocardial contractility and cardiac output. Cardiac electrophysiological changes including flattening or inversion of T waves, QT prolongation, and ST segment depression were observed in both insulin-induced and spontaneous hypoglycemia. Sympathoadrenal activation is the main cause of these changes through mechanisms that involve, but are not limited to, catecholamine-mediated hypokalemia. Hypoglycemia is also involved in platelet activation. There is growing concern about the long-term effects of hypoglycemia, especially as related to inflammation and atherogenesis.