Agnieszka Kaplon-Cieslicka

Genetic determinants of platelet reactivity during acetylsalicylic acid therapy in diabetic patients: evaluation of 27 polymorphisms within candidate genes

Summary.  Aims: Decreased platelet responsiveness to acetylsalicylic acid (ASA) reported previously in diabetic patients could be attributed to patient‐based, clinical, genetic and cellular factors. The objective of the present study was to investigate the effect of the genomic polymorphism on the platelet reactivity in diabetic patients treated with ASA. Methods and results: The study cohort consisted of 295 Caucasians with diabetes type 2 who had been taking ASA tablets at the dose of 75 mg per day for at least 3 months for primary or secondary prevention of myocardial infarction (MI). Platelet reactivity analyzes were performed using VerifyNow ASA and PFA‐100 assays. Genotyping for the selected 27 single nucleotide polymorphisms (SNPs) within 19 genes was performed using a Sequenom iPLEX platform. The results indicate that the statistically significant differences in platelet reactivity were observed in the PFA‐100 assay for SNPs in following genes: TXBA2R (rs1131882), ADRA2A (rs4311994), PLA2G7 (rs7756935) and 9p21.3 (rs10120688) (P = 0.02, P = 0.03, P = 0.02, P = 0.03, respectively, all significance levels corrected for multiple comparisons). When using the VerifyNow ASA test, a weak nominal statistical significance (i.e. before multiple comparison testing) was observed for two SNPs in the GPVI gene: rs1671152 and rs1613662 [P = 0.025 (0.5) for both SNPs, corrected for multiple comparisons test]. Conclusions: The results from the present study suggest that the four analyzed genes may contribute to platelet reactivity measured with the PFA‐100 assay in the diabetic population treated with ASA.

Effect of ASA dose doubling versus switching to clopidogrel on plasma inflammatory markers concentration in patients with type 2 diabetes and high platelet reactivity: The AVOCADO study

BACKGROUND The aim of the study was to compare the effects of 2 strategies of antiplatelet treatment (i.e., 150 mg ASA vs. 75 mg clpoidogrel) on plasma level of inflammatory markers in type 2 diabetes mellitus (T2DM) patients with high platelet reactivity (HPR). METHODS Study cohort consisted of 304 T2DM patients on chronic ASA therapy (75 mg per day) participating in the Aspirin Versus/Or Clopidogrel in Aspirin-resistant Diabetics inflammation Outcomes (AVOCADO) study. Patients with HPR defined as Platelet Function Analyzer (PFA)-100 collagene/epinephrine closure time (CEPI-CT) < 193 s (n = 80) were randomized to 150 mg of ASA or 75 mg of clopidogrel in 2:3 ratio, respectively. Concentrations of the selected inflammatory markers, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, solubleCD40 ligand (sCD40L), and high sensitivity C-reactive protein (hsCRP), were measured and compared in both treatment groups before and after 8 weeks of treatment in both groups. RESULTS Out of 234 patients included into final analysis, the total of 34.2% (n = 80) patients displayed HPR, of which 14.1% (n = 33) were randomized into 150 mg of ASA group and 20.1% (n = 47) into 75 mg of clopidogrel group. Treatment with clopidogrel was a positive predictor (stepwise multiple regression analysis) of reduction of sCD40L concentration (odds ratio [OR] 4.15; p = 0.013), while treatment with 150 mg ASA was a positive predictor of reduction of IL-6 concentration (OR 4.38; p = 0.033). There was no statistically significant differences between clopidogrel and ASA 150 mg treatment in respect to predictive value for decreased hsCRP concentrations or increased TNF-α concentrations. CONCLUSIONS Increasing the dose of ASA from 75 mg to 150 mg daily or switching ASA 75 mg to clopidogrel 75 mg daily may reduce concentrations of some inflammatory markers (in particular hsCRP, IL-6 and CD40L) in T2DM patients with HPR treated previously with 75 mg of ASA.

Younger age, higher body mass index and lower adiponectin concentration predict higher serum thromboxane B2 level in aspirin-treated patients with type 2 diabetes: an observational study

BackgroundEvidence from the literature suggests diminished acetylsalicylic acid (ASA) treatment efficacy in type 2 diabetes (DM2). High on-aspirin platelet reactivity (HAPR) in DM2 has been linked to poor glycemic and lipid control. However, there are no consistent data on the association between HAPR and insulin resistance or adipose tissue metabolic activity. The aim of this study was to assess the relationship between laboratory response to ASA and metabolic control, insulin resistance and adipokines in DM2.MethodsA total of 186 DM2 patients treated with oral antidiabetic drugs and receiving 75 mg ASA daily were included in the analysis. Response to ASA was assessed by measuring serum thromboxane B2 (TXB2) concentration and expressed as quartiles of TXB2 level. The achievement of treatment targets in terms of glycemic and lipid control, insulin resistance parameters (including Homeostatic Model Assessment-Insulin Resistance, HOMA-IR, index), and serum concentrations of high-molecular weight (HMW) adiponectin, leptin and resistin, were evaluated in all patients. Univariate and multivariate logistic regression analyses were performed to determine the predictive factors of serum TXB2 concentration above the upper quartile and above the median.ResultsSignificant trends in age, body mass index (BMI), HOMA-IR, HMW adiponectin concentration, C-reactive protein concentration and the frequency of achieving target triglyceride levels were observed across increasing quartiles of TXB2. In a multivariate analysis, only younger age and higher BMI were independent predictors of TXB2 concentration above the upper quartile, while younger age and lower HMW adiponectin concentration were predictors of TXB2 concentration above the median.ConclusionsThese results suggest that in DM2, the most important predictor of HAPR is younger age. Younger DM2 patients may therefore require total daily ASA doses higher than 75 mg, preferably as a twice-daily regimen, to achieve full therapeutic effect. Higher BMI and lower HMW adiponectin concentration were also associated with less potent ASA effect. This is the first study to demonstrate an association of lower adiponectin concentration with higher serum TXB2 level in patients treated with ASA.

Metformin treatment may be associated with decreased levels of NT-proBNP in patients with type 2 diabetes

PURPOSE Individuals with type 2 diabetes (T2DM) are at increased risk of cardiovascular disease, including heart failure (HF). In patients with T2DM elevated serum concentrations of the N-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP) correlate with cardiovascular morbidity and mortality. We aimed to identify predictors of increased serum NT-proBNP levels in patients with T2DM. METHODS The study included 185 patients with T2DM treated with either oral antidiabetic agents (49.7%) or insulin (17.8%), or both (32.5%). We divided the patients into two groups: with high (>200 pg/mL) and low (≤200 pg/mL) NT-proBNP concentrations. RESULTS We found differences between the patients with high and low NT-proBNP levels including age, prevalence of dyslipidemia and HF, history of previous myocardial infarction (MI), heart rate, hemoglobin level, platelet count, creatinine, urea and uric acid concentrations, use of beta-blockers, loop diuretics, metformin and insulin. In a multivariate analysis metformin was a negative predictor of increased NT-proBNP concentration. Age, history of HF and decreased estimated glomerular filtration rate (eGFR) were positive predictors. We found no correlation between NT-proBNP serum concentration and insulin treatment or history of coronary artery disease or MI. CONCLUSION Metformin correlates with lower concentrations of NT-proBNP in patients with T2DM.

Effect of common single-nucleotide polymorphisms in acetylsalicylic acid metabolic pathway genes on platelet reactivity in patients with diabetes

Background Platelet reactivity in patients on acetylsalicylic acid (ASA) therapy can be influenced by physiological or pathological conditions affecting ASA pharmacokinetics or pharmacodynamics. The mechanism of such variability in the therapeutic response to ASA, particularly in diabetic patients, is poorly understood. The rate of elimination of ASA and its metabolite, salicylic acid (SA), is likely a major factor determining drug efficacy. The objective of this study was to investigate the effect of genetic polymorphisms in the selected candidate genes within the ASA metabolic pathway on the platelet reactivity and concentration of ASA and thromboxane A2 (TxA2) metabolites in a population of patients with type 2 diabetes mellitus (T2DM). Material/Methods The study cohort consisted of 287 Caucasians with T2DM who had been taking ASA tablets at the dose of 75 mg per day for at least 3 months. Platelet reactivity analyses were performed using VerifyNow Aspirin and PFA-100 assays. The measured ASA metabolite included salicylic acid (ASA), and TxA2 metabolites included serum TxB2 and urinary 11-dh-TxB2. Genotyping for the selected 18 single-nucleotide polymorphisms (SNPs) within 5 genes of the ASA metabolic pathway was performed using a Sequenom iPLEX platform. Results No statistically significant association was observed between the investigated SNPs genotypes, platelet reactivity, and measured metabolites in the investigated cohort of patients. Conclusions The results of our study failed to confirm that the selected variants in the genes within the ASA metabolic pathway might contribute to platelet reactivity in a diabetic population treated with ASA.

Antidiabetic Effect of Brain-Derived Neurotrophic Factor and Its Association with Inflammation in Type 2 Diabetes Mellitus

Brain-derived neurotrophic factor (BDNF) is a neurotrophin, which plays an important role in the central nervous system, and systemic or peripheral inflammatory conditions, such as acute coronary syndrome and type 2 diabetes mellitus (T2DM). BDNF is also expressed in several nonneuronal tissues, and platelets are the major source of peripheral BDNF. Here, we reviewed the potential role of BDNF in platelet reactivity in T2DM and its association with selected inflammatory and platelet activation mediators. Besides that, we focused on adipocytokines such as leptin, resistin, and adiponectin which are considered to take part in inflammation and both lipid and glucose metabolism in diabetic patients as previous studies showed the relation between adipocytokines and BDNF. We also reviewed the evidences of the antidiabetic effect of BDNF and the association with circulating inflammatory cytokines in T2DM.

Next-generation re-sequencing of genes involved in increased platelet reactivity in diabetic patients on acetylsalicylic acid

Abstract The objective of this study was to investigate whether rare missense genetic variants in several genes related to platelet functions and acetylsalicylic acid (ASA) response are associated with the platelet reactivity in patients with diabetes type 2 (T2D) on ASA therapy. Fifty eight exons and corresponding introns of eight selected genes, including PTGS1, PTGS2, TXBAS1, PTGIS, ADRA2A, ADRA2B, TXBA2R, and P2RY1 were re-sequenced in 230 DNA samples from T2D patients by using a pooled PCR amplification and next-generation sequencing by Illumina HiSeq2000. The observed non-synonymous variants were confirmed by individual genotyping of 384 DNA samples comprising of the individuals from the original discovery pools and additional verification cohort of 154 ASA-treated T2DM patients. The association between investigated phenotypes (ASA induced changes in platelets reactivity by PFA-100, VerifyNow and serum thromboxane B2 level [sTxB2]), and accumulation of rare missense variants (genetic burden) in investigated genes was tested using statistical collapsing tests. We identified a total of 35 exonic variants, including 3 common missense variants, 15 rare missense variants, and 17 synonymous variants in 8 investigated genes. The rare missense variants exhibited statistically significant difference in the accumulation pattern between a group of patients with increased and normal platelet reactivity based on PFA-100 assay. Our study suggests that genetic burden of the rare functional variants in eight genes may contribute to differences in the platelet reactivity measured with the PFA-100 assay in the T2DM patients treated with ASA.

Lack of effect of common single nucleotide polymorphisms in leukotriene pathway genes on platelet reactivity in patients with diabetes.

The aim of the present study was to investigate the effect of genetic polymorphisms in candidate genes within the leukotriene (LT) pathway on platelet reactivity and the concentration of selected LTs in diabetic patients treated with acetylsalicylic acid (ASA). The study cohort consisted of 287 Caucasians with type 2 diabetes who had received treatment with ASA tablets (75 mg/day) for at least three months. Platelet reactivity analyses were performed using VerifyNow aspirin and PFA‑100 assays. The measured LTs included leukotriene B4 (LTB4) and leukotriene E4 (LTE4). Genotyping for the selected 25 single nucleotide polymorphisms (SNPs) within six genes of the LT pathway was performed using a Sequenom iPLEX platform. No statistically significant association was observed between the investigated SNP genotypes, platelet reactivity and measured LTs in the patient cohort. The results of our study suggest that certain polymorphisms of the LT pathway are not associated with altered platelet reactivity and the measured LTs in diabetic patients treated with ASA.

Do statins influence platelet reactivity on acetylsalicylic acid therapy in patients with type 2 diabetes

BACKGROUND Type 2 diabetes (T2DM) patients are at increased risk of cardiovascular events despite long-term acetylsalicylic acid (ASA) therapy. This study was performed to establish the prevalence of high platelet reactivity (HPR) on ASA in T2DM and to identify its predictors. METHODS The study included 185 T2DM on chronic ASA therapy and to assess platelet reactivity during long-term ASA therapy, we applied the point-of-care method VerifyNow(®) aspirin test (Accumetrics, San Diego, CA, USA). RESULTS Compared with the low platelet reactivity (LPR) group, patients with HPR had higher triglyceride levels (145 vs. 118 mg/dL, p = 0.041), were less frequently treated with statins (57.1% vs. 75.3%; p = 0.038) and tumor necrosis factor-alpha (TNF-α) concentrations were higher (2.15 vs. 1.74 pg/mL; p = 0.052). In a multivariate analysis only statin therapy (OR 0.375; 95% CI 0.15-0.91; P = 0.030) and lower concentrations of TNF-α (for each 1.0 pg/ml: or 1.3; 95% ci 1.00-1.72; p = 0.046) were predictive of LPR. CONCLUSIONS Our study provides indirect evidence that the beneficial effect of statins on platelet activity may be related to their non-lipid-mediated, pleiotropic mechanisms of action. This might have been partly related to decreased platelet reactivity in patients receiving statin therapy. In our study in patients with T2DM, platelet reactivity on ASA therapy measured with VerifyNow(®) was associated with TNF-α concentrations and statin therapy. These results may imply a role for subclinical systemic inflammation and a beneficial effect of statins in the development of HPR in T2DM.

Effect of common single nucleotide polymorphisms in COX-1 gene on related metabolic activity in diabetic patients treated with acetylsalicylic acid.

Introduction The objective of this study was to investigate the effect of common single nucleotide genomic polymorphisms in the cyclooxygenase-1 (COX-1) gene on the thromboxane A2 (TxA2) metabolite concentrations in serum and urine, as well as on prostaglandin F2α (PGF2α) urinary excretion in the diabetic population on acetylsalicylic acid (ASA) therapy. Material and methods The study cohort consisted of 284 Caucasians with diabetes type 2 who had been taking ASA tablets at the dose of 75 mg/day for at least 3 months. Genotyping for the 4 selected SNPs within the COX-1 gene (two nonsynonymous-coding variants, rs3842787 [C50T, P17L] and rs5789 [C174A, L237M]; and two other synonymous SNPs, rs3842788 [G128A, Q41Q] and rs5788 [C644A]) was performed using the Sequenom iPLEX platform. Results No statistically significant results were observed for the investigated SNPs and measured metabolites in the investigated cohort of patients. Statistically significant differences in S-TxB2 could however be observed for rs5788 in the subgroup of patients with very high S-TxB2 concentrations. In particular, more patients who were carriers of the minor allele for this polymorphism were observed in the group with S-TxB2 levels > 95th percentile, when compared with similar carriers in the group with S-TxB2 < 95th percentile (20% vs. 1.1%, respectively, p < 0.001, Mann-Whitney test). Conclusions The results of our study suggest that the four investigated common SNPs in the COX1 gene are not associated with obviously altered TxA2 metabolism and PGF2α synthesis in the investigated diabetic cohort treated with ASA.