Impact of diabetes on fibrinogen levels and its relationship with platelet reactivity and coronary artery disease: A single-centre study.

BACKGROUND: Previous reports have suggested an association between elevated fibrinogen and CAD. Few studies have so far investigated the impact of diabetes on fibrinogen levels and its association with coronary artery disease (CAD) and platelet reactivity in diabetic patients that are therefore the aims of the current study. METHODS: We measured fibrinogen in 3280 consecutive patients undergoing coronary angiography. Samples were collected at admission for fibrinogen levels assessment. Coronary disease was defined for at least 1 vessel stenosis >50% as evaluated by QCA. RESULTS: Diabetes was observed in 1201 out of 3280 patients. Diabetic patients were older with more hypercholesterolemia, hypertension, higher BMI, more renal failure, previous MI or coronary revascularization (p<0.001, respectively) and smoking (p=0.001). Diabetic patients were more often on ACE-inhibitors, ARBs, b-blockers, calcium-antagonists, diuretics, statins (p<0.001, respectively), and ASA (p=0.004). Diabetic patients displayed higher glycaemia and HbA1c (p<0.001), higher creatinine and triglycerides (p<0.001) but lower total and HDL cholesterol (p<0.001) and haemoglobin (p<0.001). Diabetic patients had higher fibrinogen levels (p=0.003), however neither diabetes nor glucose homeostasis parameters resulted as independent predictors of hyperfibrinogenemia. Furthermore, among diabetic patients, higher fibrinogen levels did not affect platelet reactivity and were not associated with the prevalence of CAD (adjusted OR[95%CI]=0.99 [0.82-1.19], p=0.9). Similar results were found for severe CAD (adjusted OR[95%CI]=0.94 [0.82-1.08], p=0.40). CONCLUSIONS: Our study showed that diabetes and glycaemic control are not independent predictors of hyperfibrinogenemia. Among diabetic patients, elevated fibrinogen is not associated with platelet reactivity and the prevalence and extent of CAD.

Homocysteine Levels Influence Platelet Reactivity in Coronary Artery Disease Patients Treated With Acetylsalicylic Acid.

BACKGROUND: Suboptimal platelet inhibition with antiplatelet treatments is associated with a severe prognosis in patients with coronary artery disease (CAD), and the identification of its determinants is still challenging. Homocysteine elevation has emerged as a prothrombotic factor, influencing coagulative status and endothelial function and potentially modulating platelet aggregation. We therefore aimed to evaluate the effects of homocysteine (Hcy) levels on platelet reactivity in patients receiving acetylsalicylic acid (ASA) with or without ADP antagonists. METHODS: Patients undergoing coronary angiography and receiving ASA (100-160 mg daily) for >7 days, with or without ADP antagonists, were included. Aggregation tests were performed by multiple electrode aggregometry. Suboptimal platelet inhibition was defined as on-treatment aggregation above the lower limit of normality. RESULTS: Our population is represented by 508 ASA-treated patients, 406 (80.1%) of whom on dual antiplatelet therapy (ASA and ADP antagonists). Hcy levels above the median (15.1 nmol/mL) were associated with male gender (P = 0.04), hypertension (P = 0.004), hypercholesterolemia (P = 0.03), aging, renal failure (P < 0.001, respectively), previous coronary bypass grafting (P = 0.04), therapy with calcium antagonists (P = 0.04) and diuretics (P = 0.001), and multivessel CAD (P = 0.03). Higher Hcy is directly related with serum creatinine and uric acid (P < 0.001). Suboptimal platelet inhibition was found in 16 patients (3.2%) for ASA and for ADP antagonists in 80 patients (19.7%). Hcy levels significantly affected suboptimal response to ASA, but not to ADP-mediated aggregation. In fact, a linear relationship was found between homocysteine and platelet reactivity after stimulation with arachidonic acid (r = 0.14, P = 0.004) and collagen (r = 0.12, P = 0.02), but not with ADP (r = 0.02, P = 0.77). Moreover, after correction for baseline differences, Hcy above the median was confirmed as an independent predictor of impaired ASA response [adjusted odds ratio (95% confidence interval) = 3.7 (1.08-12.4), P = 0.04]. CONCLUSIONS: Among patients with CAD, elevated homocysteine is an independent predictor of suboptimal response to ASA, but not to ADP antagonists.

Impact of age on mean platelet volume and its relationship with coronary artery disease: a single-centre cohort study.

UNLABELLED: Elderly patients represent a high risk category among subjects with atherosclerosis, due to the presence of comorbidities and suboptimal response to antiplatelet drugs. Mean platelet volume (MPV) has been indicated as a marker of platelet reactivity, with contrasting data on its role on coronary artery disease. Aim of the present study was to evaluate the impact of age on the MPV and its role on the extent of coronary artery disease (CAD). METHODS: Our population is represented by a cohort of 3750 patients undergoing coronary angiography. Elderly were defined according to age ≥ 75 years. MPV was measured at admission. Significant coronary artery disease was defined as a stenosis >50% in at least 1 coronary vessel, while severe CAD was defined as left main and/or three-vessel disease. RESULTS: A total of 1170 out of 3750 (31.2%) patients were ≥ 75 years old. Advanced age was associated with female gender (p<0.001), hypertension (p<0.001), renal failure (p<0.001), previous myocardial infarction (p=0.03) coronary artery bypass grafting (p<0.001) indication to angiography (p<0.001), therapy with angiotension-receptor blockers, (p=0.003), nitrates, diuretics and calcium-antagonists (p<0.001), serum creatinine (p<0.001), fibrinogen (p<0.001) and C reactive protein (p=0.02), but inversely to percutaneous coronary interventions (p=0.02), dyslipidemia, family history of CAD and smoking (p<0.001, respectively), use of statins (p=0.02) and beta blockers (p=0.003), haemoglobin, total cholesterol and triglycerides (p<0.001, respectively), white blood cells (p=0.009) and platelet count (p=0.006). Elderly patients displayed a significantly larger platelet volume (p<0.001), with a direct linear relationship between age and the MPV (r=0.08, p<0.001), with age being confirmed as an independent predictor of larger MPV (≥10.85fl) at multivariate analysis (adjusted OR [95% CI]=1.18 [1.01-1.40], p=0.04). Among the elderly, MPV value above the median (≥10.85fl) was not associated with a higher prevalence of coronary artery disease (77.3 vs. 79.4%, p=0.39, adjusted OR [95% CI]=0.94 [0.66-1.33], p=0.71), or higher prevalence of severe CAD (35.2 vs. 32.4%, p=0.28, adjusted OR [95% CI]=1.34 [0.99-1.82], p=0.06). CONCLUSION: Advanced age was directly associated with larger mean platelet volume that, however, did not contribute to explain the higher prevalence and extent of coronary artery disease observed in elderly patients.

Relationship between glycoprotein IIIa platelet receptor gene polymorphism and coronary artery disease.

Glycoprotein IIb/IIIa (GP IIb/IIIa) is a key receptor for platelet aggregation and adhesion. We investigated whether a single-nucleotide polymorphism of GP IIIa subunit (Leu33Pro-PlA(1)/PlA(2) allele) is associated with the extent of coronary artery disease (CAD) in a consecutive cohort of 1518 patients undergoing coronary angiography. Significant CAD was defined as at least a stenosis >50% and severe CAD as left main disease and/or trivessel disease. Additionally, carotid intima-media thickness (cIMT) was evaluated in 339 patients. The PlA(2) allele was observed in 458 (30.2%) patients and associated with hypercholesterolemia (P = .03). No difference was observed in the prevalence of CAD (72.6% vs 70.1%, P = .29; adjusted odds ratio, OR [95% confidence interval, CI] = 0.85 [0.67-1.08], P = .19) and severe CAD (27.5% vs 26.5%, adjusted OR [95% CI] = 0.93 [0.72-1.19], P = .55). Furthermore, Leu33Pro polymorphism did not affect cIMT and the prevalence of carotid plaques. Therefore, this polymorphism cannot be regarded as a risk factor for coronary or carotid atherosclerosis.

Platelet-larger cell ratio and the risk of periprocedural myocardial infarction after percutaneous coronary revascularization.

Periprocedural myocardial infarction (PMI) represents a frequent complication in patients undergoing percutaneous coronary revascularization. Despite great attention focused on pharmacological prevention of periprocedural damage, very little is known about using biomarkers to potentially predict the risk of PMI. Larger platelets have been associated with enhanced reactivity, increased cardiovascular risk, and higher rates of complications after coronary stenting. The platelet-larger cell ratio (P-LCR) identifies the largest-sized fraction of platelets, the proportion potentially more closely related to thrombotic events. The present study evaluated the relationship between P-LCR and PMI. We included 1,285 patients undergoing PCI. Myonecrosis biomarkers were dosed at intervals from 6 to 48 h after PCI. Periprocedural myonecrosis was defined as troponin I increase by three times the upper limit of normal (ULN) or by 50 % of an elevated baseline value, whereas PMI was defined as an increase in creatine kinase MB by 3 × ULN or 50 % of baseline. We grouped patients according to tertile values of P-LCR (<27.5; ≥35.1). Higher P-LCR was associated with age (P = 0.01), diabetes (P = 0.001), previous cerebrovascular accidents (P = 0.007), therapy with statins (P < 0.001), angiotensin receptor blockers (P < 0.001), aspirin (P = 0.002), and nitrates (P = 0.01). P-LCR was related to hemoglobin levels (P < 0.001), and inversely related to platelet count (P < 0.001) and glycemia (P = 0.05). Patients with higher P-LCR had a lower presence of coronary thrombus (P = 0.003). Higher P-LCR values did not increase the risk of PMI (P = 0.10; adjusted odds ratio (OR) (95 % confidence interval (CI)) = 0.97 (0.69-1.38)), P = 0.89) or periprocedural myonecrosis (P = 0.96; adjusted OR (95 % CI) = 1.003 (0.76-1.32), P = 0.99). Results were confirmed even in higher-risk subgroups of patients. P-LCR does not increase the risk of periprocedural myocardial infarction and myonecrosis in patients undergoing coronary stenting.

Eosinophils count and periprocedural myocardial infarction in patients undergoing percutaneous coronary interventions.

BACKGROUND: Eosinophils have been involved in a wide spectrum of pro-inflammatory and pro-thrombotic conditions, with the development of cardiovascular complications in a significant proportion of hypereosinophilic patients. However, no study has so far evaluated the impact of eosinophils levels on periprocedural myocardial infarction (PMI) in patients undergoing non-urgent percutaneous coronary interventions (PCI), that was, then, aim of current study. METHODS: In a consecutive cohort of patients, myonecrosis biomarkers were dosed at intervals from 6 to 48 h after PCI. Periprocedural myonecrosis was defined as troponin I increase by 3 times the ULN or by 50% of an elevated baseline value, whereas PMI as CKMB increase by 3 times the ULN or 50% of baseline. RESULTS: Our population is represented by 1543 patients who were divided according to tertiles of absolute eosinophils count (AEC ≤ 0.1; 0.1-0.2; >0.2 × 10ˆ3/ml). Higher AEC was related to male gender (p = 0.002), arterial hypertension (p = 0.02), diabetes (p = 0.001), previous coronary revascularization (p = 0.003 for PCI, p = 0.03 for CABG), treatment with ARBs, beta-blockers, diuretics and ASA (p < 0.001), statins (p = 0.02), calcium antagonists (p = 0.05), glycosylated hemoglobin (p < 0001), creatinine levels (p = 0.001) and platelet count (p = 0.01), while inversely with acute presentation (p < 0.001), glycemia (p = 0.03), HDL-cholesterol and C-reactive protein (p = 0.02). AEC related with multivessel coronary artery disease (p = 0.05), lesion length (p = 0.01), drug eluting stents implantation (p = 0.001) and use of kissing balloon technique (p = 0.05), while inversely to intracoronary thrombus (p < 0.001) and thrombectomy (p = 0.04). AEC did not influence the occurrence of PMI (p = 0.06, adjusted OR [95% CI] = 1.06 [0.86-1.31], p = 0.57) or myonecrosis (p = 0.15, adjusted OR [95% CI] = 1.06 [0.88-1.27], p = 0.53). Results were confirmed at subgroup analysis in higher-risk subsets of patients. CONCLUSION: In patients undergoing non-urgent PCI, eosinophils levels are not associated with the occurrence of periprocedural myocardial infarction or myonecrosis.

The diacylglycerol kinase α/atypical PKC/ß1 integrin pathway in SDF-1α mammary carcinoma invasiveness.

Diacylglycerol kinase α (DGKα), by phosphorylating diacylglycerol into phosphatidic acid, provides a key signal driving cell migration and matrix invasion. We previously demonstrated that in epithelial cells activation of DGKα activity promotes cytoskeletal remodeling and matrix invasion by recruiting atypical PKC at ruffling sites and by promoting RCP-mediated recycling of α5ß1 integrin to the tip of pseudopods. In here we investigate the signaling pathway by which DGKα mediates SDF-1α-induced matrix invasion of MDA-MB-231 invasive breast carcinoma cells. Indeed we showed that, following SDF-1α stimulation, DGKα is activated and localized at cell protrusion, thus promoting their elongation and mediating SDF-1α induced MMP-9 metalloproteinase secretion and matrix invasion. Phosphatidic acid generated by DGKα promotes localization at cell protrusions of atypical PKCs which play an essential role downstream of DGKα by promoting Rac-mediated protrusion elongation and localized recruitment of ß1 integrin and MMP-9. We finally demonstrate that activation of DGKα, atypical PKCs signaling and ß1 integrin are all essential for MDA-MB-231 invasiveness. These data indicates the existence of a SDF-1α induced DGKα - atypical PKC - ß1 integrin signaling pathway, which is essential for matrix invasion of carcinoma cells.

Impact of diabetes on uric acid and its relationship with the extent of coronary artery disease and platelet aggregation: a single-centre cohort study.

BACKGROUND: Serum uric acid (SUA) elevation has been associated with the main determinants of atherosclerosis and metabolic syndrome, although an independent relationship between SUA and coronary artery disease (CAD) has never been confirmed. Recent reports suggested a central role of SUA in diabetic patients, possibly being an early marker of impaired glucose metabolism and best predicting the risk of cardiovascular events in these patients. Aim of current study was to evaluate the relationship between diabetes and uric acid and its association with the extent of CAD and platelet aggregation among diabetics. METHODS: In diabetic patients undergoing coronary angiography, fasting samples were collected for uric acid levels assessment. Coronary disease was defined for at least 1 vessel stenosis>50% as evaluated by QCA. RESULTS: Diabetes was observed in 1173 out of 3280 (35.7%) diabetes was related to age, hypercholesterolemia, hypertension, BMI, renal failure, previous MI or coronary revascularization (p<0.001, respectively) and smoking (p=0.001). Diabetics were more frequently treated with ACE-inhibitors, ARBs, b-blockers, calcium-antagonists, diuretics, statins (p<0.001, respectively), and ASA (p=0.004). Diabetics displayed higher glycemia and HbA1c (p<0.001), higher creatinine and triglycerides (p<0.001) but lower total and HDL cholesterol (p<0.001) and haemoglobin (p<0.001). No significant difference was found in SUA levels between diabetic and non diabetic patients (p=0.09). In fact, we identified age, renal failure, hypertension, smoking, BMI, use of diuretics, statins, haemoglobin, triglycerides and HDL cholesterol levels as independent predictors of higher levels of uric acid (3rd tertile,≥6.7mg/dl or 0.39mmol/l). Among diabetic patients, no relationship was found between uric acid and the extent of coronary artery disease (p=0.27; adjusted OR [95%CI]=0.93 [0.76-1.1], p=0.48), or severe (LM-trivessel) CAD (P=0.05; adjusted OR [95%CI]=1.01 [0.86-1.18], p=0.94). Furthermore, SUA levels did not influence platelet aggregation. CONCLUSION: Ageing, BMI, renal failure, hypertension, smoking, use of statins and diuretics, haemoglobin, HDL cholesterol and tryglicerides levels but not diabetes or glycemic control are independent predictors of hyperuricemia. Among diabetic patients, higher SUA is not independently associated with the extent of CAD or with platelet aggregation.

Diabetes, glucose control and mean platelet volume: a single-centre cohort study.

UNLABELLED: Diabetes is a major determinant of cardiovascular risk, mainly due to higher prothrombotic status and enhanced platelet reactivity. Mean platelet volume (MPV) has been suggested as indicator of platelet reactivity and moreover, diabetics have been shown to have larger MPV. The aim of our study was to evaluate the impact of diabetes and glycemic control on MPV in a large cohort of patients. METHODS: Our population is represented by 3414 patients undergoing coronary angiography at Azienda Ospedaliera-Universitaria, "Maggiore della Carità", Novara, Italy. We obtained a fasting blood sample for glycemic assessment and for MPV evaluation. History of diabetes and pharmacological treatment, together with main cardiovascular risk factors were recorded. New diagnosis of diabetes was defined as nonfasting glucose >200mg/dL, fasting glucose ≥126mg/dL, or HbA1c >48mmol/L. RESULTS: Diabetes was observed in 1272 patients (37.2%). Diabetes was related to older age, waist circumference, arterial hypertension, smoking, hypercholesterolemia, renal failure, previous MI and PCI, therapy with ACE-inhibitors, ARBs, beta-blockers, diuretics, statins (respectively p<0.001) and ASA (p=0.004). Diabetics had lower haemoglobin (p<0.001), higher fibrinogen (p=0.001) and worst lipid profile (p<0.001). MPV was related with diabetes mellitus (p<0.001) and glycemic control (p=0.05; at linear regression r=0.07; p<0.001 for fasting glycaemia; r=0.09; p<0.001 for HbA1c, respectively). However, this relationship was not confirmed at multivariate analysis (OR[95%CI]=1.2[0.97-1.5], p=0.09 for diabetes, OR[95%CI]=1.05[0.96-1.15], p=0.25 for HbA1c). Independent predictors of MPV above median value (10.8fL) resulted to be age (OR[95%CI]=1.02[1.01-1.03], p=0.002), treatment with ARBs (OR[95%CI]=1.4[1.1-1.8], p=0.007) and haemoglobin levels (OR[95%CI]=1.2[1.15-1.23], p<0.001), while inverse relationship was found with total cholesterol (OR[95%CI]=0.99[0.99-1], p=0.002). CONCLUSION: Larger MPV is associated with ageing, treatment with ARBs, cholesterol and haemoglobin levels. Diabetes mellitus and glycemic control are not independently associated with larger platelet size.

Platelet PIA1/PIA2 polymorphism and the risk of periprocedural myocardial infarction in patients with acute coronary syndromes undergoing coronary angioplasty.

Acute coronary syndromes (ACSs) represent a high-risk condition, as enhanced platelet reactivity importantly influences myocardial perfusion and procedural results after percutaneous coronary intervention (PCI). In fact, higher rate of periprocedural myocardial infarction (PMI) and reduced event-free survival have been reported in these patients. The single nucleotide polymorphism Leu33Pro of platelet glycoprotein IIIa has been related to an increased platelet reactivity, a lower response to antiplatelet agents and higher risk of stent restenosis. Therefore, our aim was to evaluate the impact of this polymorphism on PMI in patients undergoing PCI for non-ST-segment elevation MI (NSTEMI). Our population is represented by 478 consecutive patients undergoing coronary angioplasty for NSTEMI. Cardiac biomarkers were monitored at intervals from 8 to 48 h after the procedure. Genetic analysis was performed to assess the presence of Leu33Pro polymorphism. A total of 156 patients (32.6%) were polymorphic. Clinical features did not differ according to genetic status, neither pharmacological treatment pre and during angioplasty. PlA carriers had lower rate of calcifications (P = 0.01) and higher coronary tortuosity (P = 0.03) at angiography and underwent more frequently to thrombectomy (P = 0.05). PCI-related complications did not differ according to genotype. Leu33Pro polymorphism was not associated with increased risk of periprocedural myonecrosis and PMI even after correction for baseline differences, [odds ratio (OR) (95% confidence interval (CI) = 0.70 (0.44-1.13), P = 0.15 for PMI and OR (95% CI) = 0.77 (0.53-1.11), P = 0.17 for myonecrosis, respectively]. Results were confirmed in high-risk subgroups of patients. In conclusion, among patients undergoing PCI for ACS, the polymorphism Leu33Pro of platelet glycoprotein IIIa is not associated with increased risk of PMI.

Benefits from new ADP antagonists as compared with clopidogrel in patients with stable angina or acute coronary syndrome undergoing invasive management: a meta-analysis of randomized trials.

AIMS: New P2Y12 receptor inhibitors have provided new and more potent antiplatelet strategies, although raising several concerns on possible increase of bleedings. The aim of current meta-analysis was to evaluate the efficacy and safety of new adenosine diphosphate (ADP) receptor antagonists as compared with clopidogrel in elective or ACS patients managed invasively. METHODS AND RESULTS: Literature archives (Pubmed, EMBASE, Cochrane) and main scientific sessions abstracts were scanned for randomized trials comparing new ADP antagonists with clopidogrel in patients with acute coronary syndromes or stable angina. Primary endpoint was mortality. Secondary endpoints were: (1) nonfatal myocardial infarction (MI), (2) recurrent ischemia symptoms or ischemia-driven revascularization (RI/IDR), (3) stent thrombosis (ST), and (4) safety endpoints, defined as for TIMI major bleeding criteria. A total of 8 randomized clinical trials were finally included, for a total population of 67,851 patients. Mean follow-up was 7.6 months, ranging from 48 hours to 30 months. New ADP antagonists significantly reduced mortality {3.1% vs. 3.6%, odds ratio [OR] [95% confidence interval (CI)], 0.86 [0.79-0.94], P = 0.0008, P(het) = 0.18}, with greater impact of oral drugs. Similar benefits were found for MI [6.1% vs. 7%; OR (95% CI) (random-effect model) = 0.88 (0.79-0.98), P = 0.01, P(het) = 0.02], RI [2.7% vs. 3.1%; OR (95% CI) = 0.85 (0.77-0.93), P = 0.0005, P(het) = 0.09], or ST [1.1% vs. 1.7%; OR (95% CI) = 0.60 (0.51-0.71), P < 0.00001, P(het) = 0.13]. By meta-regression analysis, no relationship was observed between benefits in mortality, new MI, RI, and ST with new ADP antagonists and patients' risk profile [beta (95% CI) = -0.01 [-0.30 to 0.27], P = 0.94; beta (95% CI) = -0.05 [-1.49 to 1.43], P = 0.96); beta (95% CI) = 0.19 (-0.18 to 0.57), P = 0.31, and beta (95% CI) = -0.08 (-0.86 to 0.70), P = 0.84, respectively]. CONCLUSIONS: Present meta-analysis shows that the new ADP antagonists prasugrel, ticagrelor, and cangrelor are associated to significant reduction of mortality, reinfarction, RI, and ST respect to clopidogrel alone, without significant increase in bleeding complications.

Platelet distribution width and the risk of periprocedural myocardial infarction in patients undergoing percutaneous coronary intervention.

Periprocedural myocardial infarction (PMI) still occurs in a large amount of percutaneous coronary interventions (PCI), mainly due to increased platelet activation. Platelet size has been suggested as an indicator of enhanced reactivity and platelet distribution width (PDW) could reflect morphologic changes in platelets, therefore affecting their function and potentially increasing the risk of complications after coronary stenting. Aim of the present study was to evaluate the relationship between PDW and PMI. We included 1,300 consecutive patients undergoing PCI. Myonecrosis biomarkers were dosed at intervals from 6 to 48 h after PCI. Periprocedural myonecrosis was defined as troponin I increase by three times the ULN or by 50 % of an elevated baseline value, whereas PMI as CKMB increase by three times the ULN or 50 % of baseline. We grouped patients according to tertiles values of PDW (<12.1; ≥13.9). Higher PDW was associated with age (p = 0.03), diabetes (p < 0.001), previous cerebrovascular accidents (p = 0.04), therapy with statins (p = 0.001) and ARBs (p < 0.001), ASA (p = 0.02), nitrates (p = 0.006), calcium antagonists (p = 0.05) and lower pre-procedural clopidogrel bolus (p = 0.005). PDW related with haemoglobin levels (p < 0.001), while inversely to platelet count (p < 0.001) and glycaemia (p = 0.003). Patients with larger PDW had lower presence of coronary thrombus (p < 0.001), higher rate of coronary calcifications (p = 0.02), higher stenting rate (p = 0.03) and lower rate of distal embolization (p = 0.03). Larger PDW did not increase risk of PMI (p = 0.11; adjusted OR [95 % CI] = 0.94 [0.78-1.1], p = 0.55) or periprocedural myonecrosis (p = 0.73; adjusted OR [95 % CI] = 0.95 [0.82-1.1], p = 0.51). Results were confirmed even in higher-risk subgroups of patients. In patients undergoing coronary stenting, PDW does not increase the risk of periprocedural MI and therefore should not be considered a risk factor for thrombotic periprocedural complications after PCI.

Platelet HPA-1 a/HPA-1 b polymorphism and the risk of periprocedural myocardial infarction in patients undergoing elective PCI.

Periprocedural myocardial infarction (PMI) represents a relatively common complication of percutaneous coronary intervention (PCI) and large interests have been focused on platelets in order to prevent such a complication. The single nucleotide polymorphism Leu33Pro of platelet glycoprotein IIIa has been related to an increased platelet reactivity, a lower response to antiplatelet agents and higher risk of stent restenosis. Therefore, aim of our study was to evaluate the impact of this polymorphism on PMI in elective patients undergoing PCI. Our population is represented by 422 consecutive patients with cardiac biomarkers within normality undergoing elective PCI. We measured cardiac biomarkers (CK-MB and Troponin I) at baseline, and 8, 24 and 48 hours after the procedure. For all subjects, we performed genetic analysis to assess the presence of Leu33Pro polymorphism. A total of 136 patients (32.2%) were polymorphic. Those patients were younger (p = 0.03) and more often dislypidemic (p = 0.01). Angiographic features did not differ according to genetic status. Pharmacological treatment pre and during angioplasty was similar. PCI-related complications did not differ according to genotype, with the only exception of higher rate of distal embolization in polymorphic patients. However, Leu33Pro polymorphism was not associated with increased risk of periprocedural myonecrosis and PMI even after correction for baseline differences, (respectively OR = 1.22 [0.81-1.84], p = 0.34 for myonecrosis and OR = 1.66 [0.85-3.23]; p = 0.14 for PMI). At subgroup analysis, the Leu33Pro substitution was associated with higher risk of PMI only among diabetics (adjusted OR = 4.46 [1.12-17.76], p = 0.03). Among patients undergoing elective PCI, the polymorphism Leu33Pro of platelet glycoprotein IIIa is associated with increased risk of PMI only in diabetic patients.

A diet supplemented with ALA-rich flaxseed prevents cardiomyocyte apoptosis by regulating caveolin-3 expression.

AIMS: n-3 polyunsaturated fatty acids (PUFAs) induce beneficial effects on the heart, but the mechanisms through which these effects are operated are not completely clarified yet. Among others, cardiac diseases are often associated with increased levels of cytokines, such as tumour necrosis factor-α (TNF), that cause degeneration and death of cardiomyocytes. The present study has been carried out to investigate (i) the potential anti-apoptotic effects induced by the n-3 polyunsaturated α-linolenic acid (ALA) in experimental models of cardiac diseases characterized by high levels of TNF, and (ii) the potential role of caveolin-3 (Cav-3) in the mechanisms involved in this process. METHODS AND RESULTS: An ALA-rich flaxseed diet, administered from weaning to hereditary cardiomyopathic hamsters, prevented the onset of myocardial apoptosis associated with high plasma and tissue levels of TNF preserving caveolin-3 expression. To confirm these findings, isolated neonatal mouse cardiomyocytes were exposed to TNF to induce apoptosis. ALA pre-treatment greatly enhanced Cav-3 expression hampering the internalization of the caveolar TNF receptor and, thus, determining the abortion of the apoptotic vs. survival cascade. CONCLUSION: This study unveiled the Cav-3 pivotal role in defending cardiomyocytes against the TNF pro-apoptotic action and the ALA capacity to regulate this mechanism preventing cardiac degenerative diseases.

Mean platelet volume is not associated with platelet reactivity and the extent of coronary artery disease in diabetic patients.

Platelets play a central role in the pathogenesis of coronary artery disease (CAD). Mean platelet volume (MPV) is an indicator of platelet activation, and has been demonstrated to be correlated with platelet reactivity. Diabetic patients have been shown to have larger MPV, that may contribute to higher platelet reactivity and atherothrombotic complications observed in these patients. Therefore, the aim of the current study was to investigate whether MPV is associated with platelet reactivity and the extent of CAD among diabetic patients. We performed a cohort study including 1016 consecutive diabetic patients undergoing coronary angiography at the University Hospital 'Maggiore della Carita', Novara, Italy. CAD is defined as stenosis above 50% in at least one coronary vessel at coronary angiography. Platelet reactivity was evaluated in 50 diabetic patients without history of CAD and who were free (in the past month) from medications which may affect platelet aggregation. Platelet aggregation was evaluated by light transmission aggregometry after stimulation with 1 µg/ml collagen type I. We additionally evaluated platelet surface expression of P-selectin after stimulation with U46619 (a stable synthetic analogue of the prostaglandin PGH2) and plasma concentration of thromboxane B2 (TxB2). Patients were grouped according to tertile values of MPV (<10.6 fl, group 1; 10.6-11.3 fl, group 2; >11.4 fl, group 3). MPV was associated with age (P=0.011), baseline fasting glucose (P=0.044), glycosylated haemoglobin (P=0.005), creatinine (P=0.052) and haemoglobin (P=0.003), but inversely related to platelet count (P<0.001) and triglycerides (P=0.031). Larger MPV was associated with therapy with statins (P=0.012) and diuretics (P=0.021). CAD was observed in 826 patients (81.3%). MPV was not associated with the prevalence of CAD [odds ratio (OR), 0.85 (0.7-1.03), P=0.11]. The results were confirmed in terms of severe CAD [OR, 1.03 (0.88-1.21), P=0.7]. The absence of any significant relationship between MPV and CAD was confirmed after correction for baseline confounding factors [OR, 0.9 (0.75-1.08), P=0.19]. Finally, MPV was not related to platelet reactivity. This is the first study showing that in diabetic patients MPV is not related to platelet reactivity and the prevalence and extent of CAD. Therefore, MPV may not be considered a risk factor for CAD among diabetic patients.

Acylated and unacylated ghrelin impair skeletal muscle atrophy in mice.

Cachexia is a wasting syndrome associated with cancer, AIDS, multiple sclerosis, and several other disease states. It is characterized by weight loss, fatigue, loss of appetite, and skeletal muscle atrophy and is associated with poor patient prognosis, making it an important treatment target. Ghrelin is a peptide hormone that stimulates growth hormone (GH) release and positive energy balance through binding to the receptor GHSR-1a. Only acylated ghrelin (AG), but not the unacylated form (UnAG), can bind GHSR-1a; however, UnAG and AG share several GHSR-1a-independent biological activities. Here we investigated whether UnAG and AG could protect against skeletal muscle atrophy in a GHSR-1a-independent manner. We found that both AG and UnAG inhibited dexamethasone-induced skeletal muscle atrophy and atrogene expression through PI3Kß-, mTORC2-, and p38-mediated pathways in myotubes. Upregulation of circulating UnAG in mice impaired skeletal muscle atrophy induced by either fasting or denervation without stimulating muscle hypertrophy and GHSR-1a-mediated activation of the GH/IGF-1 axis. In Ghsr-deficient mice, both AG and UnAG induced phosphorylation of Akt in skeletal muscle and impaired fasting-induced atrophy. These results demonstrate that AG and UnAG act on a common, unidentified receptor to block skeletal muscle atrophy in a GH-independent manner.

Alterations of negative regulators of cytokine signalling in immunodeficiency-related non-Hodgkin lymphoma.

We investigated immunodeficiency-related non-Hodgkin lymphoma for the presence of molecular alterations affecting negative regulators of the Janus family protein tyrosine kinase/signal transducer and activator of transcription pathway. Protein tyrosine phosphatase, non-receptor type 6/Src homology 2-containing tyrosine phosphatase-1 epigenetic silencing was recurrent in primary effusion lymphoma (100%), and diffuse large B-cell lymphoma (63%), with a higher prevalence in the non-germinal centre subtype, and was associated with the activation of the Janus family protein tyrosine kinase/signal transducer and activator of transcription 3 pathway. Suppressor of cytokine signalling (SOCS)1 and SOCS3 epigenetic silencing were occasionally detected, whereas SOCS1 was frequently mutated in diffuse large B-cell lymphoma and polymorphic post-transplant lymphoproliferative disorders, possibly as a cause of aberrant somatic hypermutation. However, the mutation profile of the coding region of the gene was different from that expected from the aberrant somatic hypermutation process, suggesting that, at least in some cases, SOCS1 mutations may have been selected for their functional activity.

The phytoestrogen 8-prenylnaringenin inhibits agonist-dependent activation of human platelets.

BACKGROUND: Phytoestrogens are plant-derived polyphenolic compounds that exert beneficial effects on human health, mostly related to their estrogen mimetic activity. In particular a strong correlation between phytoestrogens intake and a lower risk of cardiovascular diseases has been reported. The flavanone 8-prenylnaringenin, extracted from hop flowers, has been identified as a novel phytoestrogen, unique with respect to estrogen receptors specificity and potency. However, to date no investigations on the 8-prenylnaringenin role in modulating platelet function have been undertaken. METHODS: We evaluated the effect of 8-prenylnaringenin on platelet aggregation, intracellular calcium mobilization and protein phosphorylation triggered by thrombin and collagen, and platelet adhesion and dense granule secretion triggered by collagen. RESULTS: 8-Prenylnaringenin inhibited platelet aggregation induced by different agonists and platelet adhesion to collagen matrix. 8-Prenylnaringenin directly increased intracellular cAMP and cGMP levels and thus promoted VASP phosphorylation. However, these molecular events were not responsible for the inhibitory action of 8-prenylnaringenin on platelets. Moreover, 8-prenylnaringenin inhibited the phosphorylation of Pyk2, Akt, and ERK1/2. Finally, 8-prenylnaringenin suppressed the mobilization of calcium and the secretion of dense granules. All these effects were independent of estrogen receptors recruitment. CONCLUSIONS: 8-Prenylnaringenin exerted anti-aggregatory and anti-adhesive effects on human platelets, independently of estrogen receptors, acting as an inhibitor of multiple proteins essential for the morphological and biochemical transformations that occur during platelet activation and aggregation. GENERAL SIGNIFICANCE: 8-Prenylnaringenin may represent a useful tool in the therapy and prevention of vascular diseases associated with platelet aggregation, such as atherosclerosis, myocardial infarction, coronary artery disease, and thrombosis.

Dehydroepiandrosterone-sulfate inhibits thrombin-induced platelet aggregation.

Dehydroepiandrosterone (DHEA) and its sulfated form, DHEA-S, are the most abundant steroids circulating in human blood. DHEA stimulates endothelial cells to release high amounts of nitric oxide in the circulation. Nitric oxide activates guanylyl cyclase in platelets thus decreasing the responsiveness of these cells to physiological agonists. However, the impact of DHEA-S and DHEA on platelet function and their possible role in modulating the response of human platelets to physiological agonists were not yet investigated. Here, DHEA-S, but not DHEA, inhibited in vitro thrombin-dependent platelet aggregation in a dose-dependent manner. DHEA-S exerted this effect by decreasing thrombin-dependent dense granule secretion, and so impairing the positive feed-back loop provided by ADP. Furthermore, DHEA-S inhibited thrombin-dependent activation of Akt, ERK1/2, and p38 MAP kinase. Although both DHEA-S and DHEA directly activated in platelets the inhibitory cGMP/PGK/VASP pathway, these events were not responsible for the inhibitory action of DHEA-S in platelets. In addition DHEA-S acted in synergism with nitric oxide in inhibiting platelet aggregation. In conclusion DHEA-S inhibited platelet activation caused by a mild stimulus without completely hampering platelet functionality and thus DHEA-S may participate in the physiological mechanisms that maintain circulating platelets in a resting state. The role played by DHEA-S could be relevant mainly when the functionality of the vascular endothelium is compromised.

SAP-mediated inhibition of diacylglycerol kinase α regulates TCR-induced diacylglycerol signaling.

Diacylglycerol kinases (DGKs) metabolize diacylglycerol to phosphatidic acid. In T lymphocytes, DGKα acts as a negative regulator of TCR signaling by decreasing diacylglycerol levels and inducing anergy. In this study, we show that upon costimulation of the TCR with CD28 or signaling lymphocyte activation molecule (SLAM), DGKα, but not DGKζ, exits from the nucleus and undergoes rapid negative regulation of its enzymatic activity. Inhibition of DGKα is dependent on the expression of SAP, an adaptor protein mutated in X-linked lymphoproliferative disease, which is essential for SLAM-mediated signaling and contributes to TCR/CD28-induced signaling and T cell activation. Accordingly, overexpression of SAP is sufficient to inhibit DGKα, whereas SAP mutants unable to bind either phospho-tyrosine residues or SH3 domain are ineffective. Moreover, phospholipase C activity and calcium, but not Src-family tyrosine kinases, are also required for negative regulation of DGKα. Finally, inhibition of DGKα in SAP-deficient cells partially rescues defective TCR/CD28 signaling, including Ras and ERK1/2 activation, protein kinase C membrane recruitment, induction of NF-AT transcriptional activity, and IL-2 production. Thus SAP-mediated inhibition of DGKα sustains diacylglycerol signaling, thereby regulating T cell activation, and it may represent a novel pharmacological strategy for X-linked lymphoproliferative disease treatment.