Reduced platelet glycoprotein Ibα shedding accelerates thrombopoiesis and COX-1 recovery: implications for aspirin dosing regimen.

Cardiovascular (CV) disease prevention with low-dose aspirin can be less effective in patients with a faster recovery of platelet (PLT) cyclooxygenase (COX)-1 activity during the 24-hour dosing interval. We previously showed that incomplete suppression of TXA2 over 24 hours can be rescued by a twice daily aspirin regimen. Here we show that reduced PLT glycoprotein (GP)Ibα shedding characterizes patients with accelerated COX-1 recovery and may contribute to higher thrombopoietin (TPO) production and higher rates of newly formed PLT, escaping aspirin inhibition over 24 hours. Two hundred aspirin-treated patients with high CV risk (100 with type 2 diabetes mellitus) were stratified according to the kinetics of PLT COX-1 activity recovery during the 10- to 24-hour dosing interval. Whole proteome analysis showed that PLT from patients with accelerated COX-1 recovery were enriched in proteins involved in cell survival, inhibition of apoptosis and cellular protrusion formation. In agreement, we documented increased plasma TPO, megakaryocyte maturation and proplatelet formation, and conversely increased PLT galactose and reduced caspase 3, phosphatidylserine exposure and ADAM17 activation, translating into diminished GPIbα cleavage and glycocalicin (GC) release. Treatment of HepG2 cells with recombinant GC led to a dose-dependent reduction of TPO mRNA in the liver, suggesting that reduced GPIbα ectodomain shedding may unleash thrombopoiesis. A cluster of clinical markers, including younger age, non-alcoholic fatty liver disease, visceral obesity and higher TPO/GC ratio, predicted with significant accuracy the likelihood of faster COX-1 recovery and suboptimal aspirin response. Circulating TPO/GC ratio, reflecting a dysregulation of PLT lifespan and production, may provide a simple tool to identify patients amenable to more frequent aspirin daily dosing.

GCN5 contributes to intracellular lipid accumulation in human primary cardiac stromal cells from patients affected by Arrhythmogenic cardiomyopathy.

Arrhythmogenic cardiomyopathy (ACM) is a genetic disease associated with sudden cardiac death and cardiac fibro-fatty replacement. Over the last years, several works have demonstrated that different epigenetic enzymes can affect not only gene expression changes in cardiac diseases but also cellular metabolism. Specifically, the histone acetyltransferase GCN5 is known to facilitate adipogenesis and modulate cardiac metabolism in heart failure. Our group previously demonstrated that human primary cardiac stromal cells (CStCs) contribute to adipogenesis in the ACM pathology. Thus, this study aims to evaluate the role of GCN5 in ACM intracellular lipid accumulation. To do so, CStCs were obtained from right ventricle biopsies of ACM patients and from samples of healthy cadaveric donors (CTR). GCN5 expression was increased both in ex vivo and in vitro ACM samples compared to CTR. When GCN5 expression was silenced or pharmacologically inhibited by the administration of MB-3, we observed a reduction in lipid accumulation and a mitigation of reactive oxygen species (ROS) production in ACM CStCs. In agreement, transcriptome analysis revealed that the presence of MB-3 modified the expression of pathways related to cellular redox balance. Altogether, our findings suggest that GCN5 inhibition reduces fat accumulation in ACM CStCs, partially by modulating intracellular redox balance pathways.

A randomized double-blind trial of 3 aspirin regimens to optimize antiplatelet therapy in essential thrombocythemia.

Essential thrombocythemia (ET) is characterized by abnormal megakaryopoiesis and enhanced thrombotic risk. Once-daily low-dose aspirin is the recommended antithrombotic regimen, but accelerated platelet generation may reduce the duration of platelet cyclooxygenase-1 (COX-1) inhibition. We performed a multicenter double-blind trial to investigate the efficacy of 3 aspirin regimens in optimizing platelet COX-1 inhibition while preserving COX-2-dependent vascular thromboresistance. Patients on chronic once-daily low-dose aspirin (n = 245) were randomized (1:1:1) to receive 100 mg of aspirin 1, 2, or 3 times daily for 2 weeks. Serum thromboxane B2 (sTXB2), a validated biomarker of platelet COX-1 activity, and urinary prostacyclin metabolite (PGIM) excretion were measured at randomization and after 2 weeks, as primary surrogate end points of efficacy and safety, respectively. Urinary TX metabolite (TXM) excretion, gastrointestinal tolerance, and ET-related symptoms were also investigated. Evaluable patients assigned to the twice-daily and thrice-daily regimens showed substantially reduced interindividual variability and lower median (interquartile range) values for sTXB2 (ng/mL) compared with the once-daily arm: 4 (2.1-6.7; n = 79), 2.5 (1.4-5.65, n = 79), and 19.3 (9.7-40; n = 85), respectively. Urinary PGIM was comparable in the 3 arms. Urinary TXM was reduced by 35% in both experimental arms. Patients in the thrice-daily arm reported a higher abdominal discomfort score. In conclusion, the currently recommended aspirin regimen of 75 to 100 once daily for cardiovascular prophylaxis appears to be largely inadequate in reducing platelet activation in the vast majority of patients with ET. The antiplatelet response to low-dose aspirin can be markedly improved by shortening the dosing interval to 12 hours, with no improvement with further reductions (EudraCT 2016-002885-30).

Lipidomics analysis of monocytes from patients with acute myocardial infarction reveals lactosylceramide as a new player in monocyte migration.

Monocyte recruitment after vascular injury and their migration through the vessel wall represent crucial events in the initiation, progression, and destabilization of atherosclerotic plaque. Circulating monocytes are exposed to stimuli that alter their physiological state, and among them, lipids play a key role. Several studies investigated the mechanisms by which lipids affect monocyte functions promoting coronary atherosclerotic plaque initiation, but information on the relationship between lipid composition and function of monocyte is scant. We aimed at studying the migration of circulating monocytes isolated from patients with acute myocardial infarction (AMI) at hospital presentation and investigating its correlation with cellular lipid profile. The migration of monocytes was tested using both fetal bovine serum (FBS) and autologous serum as chemoattractant stimuli. Monocyte lipid profile was evaluated through an untargeted lipidomics approach, using a liquid chromatography/time-of-flight mass spectrometry platform. We observed that AMI patients' monocytes showed a significant increase in FBS and autologous serum-mediated migration compared to controls. Moreover, a different monocyte lipidomic profile between the two study groups was detected. In particular, AMI patients' monocytes showed an altered composition in ceramides, with an increase in lactosylceramide and in phospholipids (ie, phosphatidylethanolamine and lisophosphatidylethanolamine). Of note, a positive correlation between lactosylceramide levels and monocyte migration was observed. Furthermore, the lactosylceramide synthase inhibition significantly reduced FBS-induced monocyte migration. Our results highlight the influence of lactosylceramide on the monocyte migration capacity, pointing out a new possible mechanism of lipids in the onset of atherothrombosis and, hence, in AMI.

An Optimized MRM-Based Workflow of the l-Arginine/Nitric Oxide Pathway Metabolites Revealed Disease- and Sex-Related Differences in the Cardiovascular Field.

Clinical data indicate that low circulating l-homoarginine (HArg) concentrations are associated with cardiovascular (CV) disease, CV mortality, and all-cause mortality. A high number of LC-based analytical methods for the quantification of HArg, in combination with the l-arginine (Arg)-related pathway metabolites, have been reported. However, these methods usually consider a limited panel of analytes. Thus, in order to achieve a comprehensive picture of the Arg metabolism, we described an improved targeted metabolomic approach based on a multiple reaction monitoring (MRM) mass spectrometry method for the simultaneous quantification of the Arg/nitric oxide (NO) pathway metabolites. This methodology was then employed to quantify the plasma concentrations of these analytes in a cohort of individuals with different grades/types of coronary artery disease (CAD) in order to increase knowledge about the role of HArg and its associated metabolites in the CV field. Our results showed that the MRM method here implemented is suitable for the simultaneous assessment of a wide panel of amino acids involved in the Arg/NO metabolic pathway in plasma samples from patients with CV disease. Further, our findings highlighted an impairment of the Arg/NO metabolic pathway, and suggest a sex-dependent regulation of this metabolic route.

Plasma phospholipid dysregulation in patients with cystathionine-ß synthase deficiency.

BACKGROUND & AIMS: Patients with cystathionine ß-synthase deficiency (CBSD) exhibit high circulating levels of homocysteine and enhanced lipid peroxidation. We have characterized the plasma lipidome in CBSD patients and related lipid abnormalities with reactions underlying enhanced homocysteine levels. METHODS AND RESULTS: Using an ultra-high-performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry method, plasma lipids were determined with an untargeted lipidomics approach in 11 CBSD patients and 11 matched healthy subjects (CTRL). Compared to CTRL, CBSD patients had a higher medium and long-chain polyunsaturated fatty acids (PUFA) content in phosphatidylethanolamine (PE) and lysophosphatidylethanolamine (LPE) species (p < 0.02), and depletion of phosphatidylcholine (PC; p = 0.02) and of lysophosphatidylcholine (LPC; p = 0.003) species containing docosahexaenoic acid (DHA), suggesting impaired phosphatidylethanolamine-N-methyltransferase (PEMT) activity. PEMT converts PE into PC using methyl group by S-adenosylmethionine (SAM) thus converted in S-adenosylhomocysteine (SAH). Whole blood SAM and SAH concentrations by liquid chromatography tandem mass spectrometry were 1.4-fold (p = 0.015) and 5.3-fold (p = 0.003) higher in CBSD patients than in CTRL. A positive correlation between SAM/SAH and PC/PE ratios (r = 0.520; p = 0.019) was found. CONCLUSIONS: A novel biochemical abnormality in CBSD patients consisting in depletion of PC and LPC species containing DHA and accumulation of PUFA in PE and LPE species is revealed by this lipidomic approach. Changes in plasma SAM and SAH concentrations are associated with such phospholipid dysregulation. Given the key role of DHA in thrombosis prevention, depletion of PC species containing DHA in CBSD patients provides a new direction to understand the poor cardiovascular outcome of patients with homocystinuria.

12(S)-Hydroxyeicosatetraenoic acid downregulates monocyte-derived macrophage efferocytosis: New insights in atherosclerosis.

The involvement of 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE), a 12-lipooxygenase product of arachidonic acid, has been suggested in atherosclerosis. However, its effect on macrophage functions is not completely understood, so far. The uptake of apoptotic cells (efferocytosis) by macrophages is an anti-inflammatory process, impaired in advanced atherosclerotic lesions. This process induces the release of the anti-inflammatory cytokine interleukin-10 (IL-10), and it is regulated by Rho-GTPases, whose activation involves the isoprenylation, a modification inhibited by statins. We assessed 12-HETE levels in serum of coronary artery disease (CAD) patients, and explored 12(S)-HETE in vitro effect on monocyte-derived macrophage (MDM) efferocytosis. Sixty-four CAD patients and 24 healthy subjects (HS) were enrolled. Serum 12-HETE levels were measured using a tandem mass spectrometry method. MDMs, obtained from a spontaneous differentiation of adherent monocytes, were treated with 12(S)-HETE (10-50 ng/mL). Efferocytosis and RhoA activation were evaluated by flow cytometry. IL-10 was measured by ELISA. CAD patients showed increased 12-HETE serum levels compared to HS (665.2 [438.1-896.2] ng/mL and 525.1 [380.1-750.1] ng/mL, respectively, p < 0.05) and reduced levels of IL-10. MDMs expressed the 12(S)-HETE cognate receptor GPR31. CAD-derived MDMs displayed defective efferocytosis vs HS-MDMs (9.4 [7.7-11.3]% and 11.1 [9.6-14.1]% of MDMs that have engulfed apoptotic cells, respectively, p < 0.01). This reduction is marked in MDMs obtained from patients not treated with statin (9.3 [7.4-10.6]% statin-free CAD vs HS, p = 0.01; and 9.9 [8.6-11.6]% statin-treated CAD vs HS, p = 0.07). The in vitro treatment of MDMs with 12(S)-HETE (20 ng/mL) induced 20% decrease of efferocytosis (p < 0.01) and 71% increase of RhoA activated form (p < 0.05). Atorvastatin (0.1 µM) counteracted these 12(S)-HETE-mediated effects.These results show a 12(S)-HETE pro-inflammatory effect and suggest a new potential contribution of this mediator in the development of atherosclerosis.

Very-low-dose twice-daily aspirin maintains platelet inhibition and improves haemostasis during dual-antiplatelet therapy for acute coronary syndrome.

Higher aspirin doses may be inferior in ticagrelor-treated acute coronary syndrome (ACS) patients and reducing bleeding risk whilst maintaining antithrombotic benefits could improve outcomes. We characterized the pharmacodynamics of a novel dual-antiplatelet-therapy regimen consisting of very-low-dose twice-daily (BD) aspirin with standard-dose ticagrelor. A total of 20 ticagrelor-treated ACS patients entered a randomized crossover to take aspirin 20 mg BD (12-hourly) during one 14-day period and 75 mg once-daily (OD) in the other. After 14 days of treatment, serum thromboxane (TX)B2 and light-transmittance aggregometry were assessed pre- and 2 h post-morning-dose, bleeding time was measured post-dose, and TXA2 and prostacyclin stable metabolites were measured in urine collected 2 h post-morning-dose. Data are expressed as mean ± SD. After 14 days treatment, serum TXB2 levels were significantly greater 2 h post-dosing with aspirin 20 mg BD vs. 75 mg OD (3.0 ± 3.6 ng/mL vs. 0.8 ± 1.9 ng/mL; p = 0.018) whereas pre-dosing levels were not significantly different (3.5 ± 4.1 ng/mL vs. 2.5 ± 3.1 ng/mL, p = 0.23). 1-mmol/L arachidonic acid-induced platelet aggregation was similarly inhibited by both regimens pre-dose (8.5 ± 14.3% vs. 5.1 ± 3.6%, p = 0.24) and post-dose (8.7 ± 14.2% vs. 6.6 ± 5.3%; p = 0.41). Post-dose bleeding time was shorter with 20 mg BD (680 ± 306 s vs. 834 ± 386 s, p = 0.02). Urinary prostacyclin and TX metabolite excretion were not significantly different. In conclusion, compared to aspirin 75 mg OD, aspirin 20 mg BD provided consistent inhibition of platelet TXA2 release and aggregation, and improved post-dose hemostasis, in ticagrelor-treated ACS patients. Further studies are warranted to assess whether this regimen improves the balance of clinical efficacy and safety.

Role of thromboxane-dependent platelet activation in venous thrombosis: Aspirin effects in mouse model.

Recent trials suggest that Aspirin (ASA) reduces the incidence of venous thromboembolism in human. However, the molecular mechanisms underlying this effect are still unclear. In this study we assessed the effects of ASA in venous thrombosis mouse model induced by inferior vena cava (IVC) ligation and we investigated the mechanisms responsible for this effect. ASA (3mg/kg daily for 2 days) treatment decreased the thrombus size, the amounts of tissue factor activity in plasma microvesicles (TF-MP) and the levels of 2,3-dinor Thromboxane B2 (TXB-M) in urine compared to control mice. Interestingly, the thrombus size positively correlated with both TF-MP activity and TXB-M. In addition, positive correlation was observed between TF-MP activity and TXB-M. A reduced number of neutrophils and monocytes, and of TF-positive cells accompanied to a lower amount of fibrin and neutrophil extracellular traps (NETs) were also found in thrombi of ASA-treated mice. Similar results were obtained when mice were treated 24h before IVC ligation with SQ29548 (1mg/kg), a selective thromboxane receptor antagonist. In addition, transfusion of platelets in SQ29548 treated-mice excluded the likelihood of a redundant role of platelet-TP receptor in this context. Finally, incubation of macrophages and neutrophils with SQ29548 prevented TF activity and/or NETs formation induced by supernatant of activated platelets or by IBOP, a selective thromboxane analogue. In conclusion, ASA, suppressing TXA2, prevents macrophages and neutrophils activation and markedly reduces thrombus size with a mechanism most likely dependent of the inhibition of TF activity and NETs formation. These results provide a new link between platelet-produced thromboxane and the occurrence of venous thrombosis.

The red blood cell: a new key player in cardiovascular homoeostasis? Focus on the nitric oxide pathway.

RBCs (red blood cells) have a fundamental role in the regulation of vascular homoeostasis thanks to the ability of these cells to carry O2 (oxygen) between respiratory surfaces and metabolizing tissues and to release vasodilator compounds, such as ATP and NO (nitric oxide), in response to tissue oxygenation. More recently it has been shown that RBCs are also able to produce NO endogenously as they express a functional NOS (nitric oxide synthase), similar to the endothelial isoform. In addition, RBCs carry important enzymes and molecules involved in L-arginine metabolism, such as arginase, NO synthesis inhibitors and the cationic amino acid transporters. Altogether these findings strongly support the role of these cells as producers, vehicles and scavengers of NO, therefore affecting several physiological processes such as blood rheology and cell adhesion. Consequently, the importance of alterations in the L-arginine/NO metabolic pathway induced by specific conditions, e.g. oxidative stress, in different pathological settings have been investigated. In the present review we discuss the role of RBCs in vascular homoeostasis, focusing our attention on the importance of the NO pathway alterations in cardiovascular diseases and their relationship to major risk factors.

Hemostatic system in Takotsubo patients at long-term follow-up: A hidden activation?

BACKGROUND: Takotsubo cardiomyopathy (TTS) has long been considered a benign condition, despite recurrent events and long-term adverse outcomes are often reported. Endothelial damage, blood hyperviscosity, and platelet activation described in acute phase persist in long-term follow-up; however, TTS pathophysiology is still not fully understood. Here, we explored the hemostatic system at a median of 3.1 years after TTS to uncover additional long-lasting changes in these patients. METHODS: We assessed hemostatic parameters in women with TTS (n = 23) or coronary artery disease (CAD; n = 31) and in control women (n = 26) age-matched, by thromboelastographic analysis, prothrombin time (PT) and partial thromboplastin time (aPTT) coagulation assays and microparticle exposing Tissue Factor (MP-TF). Functional fibrinogen and fibrin polymerization were analyzed by Clauss method and spectrophotometry, respectively. Platelet reactivity was evaluated by light transmission aggregometry, whereas plasminogen activator inhibitor-1 (PAI-1) and brain-derived neurotrophic factor (BDNF) were measured by ELISA kit. RESULTS: Compared with control subjects, TTS patients exhibit an accelerated clot formation, higher percentage of fibrin polymerization and higher PAI-1 levels. Compared with CAD, TTS patients showed sustained residual platelet activation but decreased functional fibrinogen, fibrin polymerization and MP-TF levels, prolonged aPTT and a marked BDNF increase. CONCLUSIONS: The long-term activation of hemostatic system observed in TTS patients compared to control subjects suggests a persistent humoral abnormality that may be related to the propensity for TTS recurrence. The higher residual platelet activity observed in TTS than in CAD patients invites investigation on TTS-tailored antiplatelet therapy potentially needed to prevent TTS adverse outcomes.

N-Acetylcysteine Inhibits Platelet Function through the Regeneration of the Non-Oxidative Form of Albumin.

N-acetylcysteine (NAC) is able to break down protein disulfides, generating free thiols. This mechanism occurs on mixed disulfides of albumin (HSA) to form mercaptoalbumin (HMA), the main antioxidant species in the plasma. Circulating HSA exists in two main forms: the reduced form (HMA), and the oxidized forms, whose predominant modification is cystenylation (HSA-Cys). Increased levels of oxidized HSA have been detected in several diseases associated with oxidative stress. This study showed that NAC inhibits platelet aggregation by restoring HMA. In addition, the regeneration of HMA by NAC inhibits platelet functions such as intracellular calcium mobilization, reactive oxygen species generation, arachidonic acid metabolites synthesis, and adhesion to the collagen matrix. In our conditions, the exposure of platelets to NAC did not increase GSH levels. However, the inhibition of platelet aggregation was also detected following treatment of platelet-rich plasma with GSH, which, similarly to NAC, reduced HSA-Cys levels. Furthermore, this study showed that cysteine, another compound able to restore HMA by reducing the HSA-Cys content, inhibited platelet aggregation to a similar extent as NAC. The results obtained in this study suggest a new mechanism by which NAC can modulate platelet activation and suggest its possible use as an antiplatelet drug in conditions associated with oxidative stress.

Oxidative Stress and Arginine/Nitric Oxide Pathway in Red Blood Cells Derived from Patients with Prediabetes.

The effects of the oral glucose tolerance test (OGTT) on red blood cells (RBCs) have not been thoroughly investigated, although it is known that the ingestion of 75 g of glucose during OGTT results in a systemic state of inflammation and oxidative stress. Therefore, we evaluated the effect of OGTT on oxidative stress and L-arginine/Nitric Oxide (L-Arg/NO) metabolic pathway in RBCs obtained from patients with prediabetes. Blood samples were collected from all participants before (T0) and at 10 (T1), 20 (T2), 30 (T3), 60 (T4), 90 (T5), 120 (T6), 150 (T7), and 180 (T8) minutes after glucose loading. Results showed a significant increase in oxidative stress status characterized by a rise in the GSSG/GSH ratio at T4 and T6 that increased in parallel with a reduction of NO production in RBCs. In addition, in this time frame, increased exposure of phosphatidylserine on RBCs membrane was observed. These metabolic modifications were rescued at T8, together with an increase in activated RBC NO synthase expression. These findings provide a possible explanation of the phenomena occurring after glucose loading and suggest that, even in the early stages of diabetes, it may be important to avoid acute variations in glycemia in order to prevent diabetic complications.

Platelet thromboxane inhibition by low-dose aspirin in polycythemia vera: Ex vivo and in vivo measurements and in silico simulation.

Low-dose aspirin is currently recommended for patients with polycythemia vera (PV), a myeloproliferative neoplasm with increased risk of arterial and venous thromboses. Based on aspirin pharmacodynamics in essential thrombocythemia, a twice-daily regimen is recommended for patients with PV deemed at particularly high thrombotic risk. We investigated the effects of low-dose aspirin on platelet cyclooxygenase activity and in vivo platelet activation in 49 patients with PV, as assessed by serum thromboxane (TX) B2 and urinary TXA2 /TXB2 metabolite (TXM) measurements, respectively. A previously described pharmacokinetic-pharmacodynamic in silico model was used to simulate the degree of platelet TXA2 inhibition by once-daily (q.d.) and twice-daily (b.i.d.) aspirin, and to predict the effect of missing an aspirin dose during q.d. and b.i.d. regimens. Serum TXB2 averaged 8.2 (1.6-54.7) ng/ml and significantly correlated with the platelet count (γ = 0.39) and urinary TXM (γ = 0.52) in multivariable analysis. One-third of aspirin-treated patients with PV displayed less-than-maximal platelet TXB2 inhibition, and were characterized by significantly higher platelet counts and platelet-count corrected serum TXB2 than those with adequate inhibition. Eight patients with PV were sampled again after 12 ± 4 months, and had reproducible serum TXB2 and urinary TXM values. The in silico model predicted complete inhibition of platelet-derived TXB2 by b.i.d. aspirin, a prediction verified in a patient with PV with the highest TXB2 value while on aspirin q.d. and treated short-term with a b.i.d. regimen. In conclusion, one in three patients with PV on low-dose aspirin display less-than-maximal inhibition of platelet TXA2 production. Serum TXB2 measurement can be a valuable option to guide precision dosing of antiplatelet therapy in patients with PV.

Enduring Reactive Oxygen Species Emission Causes Aberrant Protein S-Glutathionylation Transitioning Human Aortic Valve Cells from a Sclerotic to a Stenotic Phenotype.

Aims: During calcific aortic valve stenosis (CAVS) progression, oxidative stress and endothelial dysfunction mark the initial pathogenic steps with a parallel dysregulation of the antioxidant systems. Here, we tested whether oxidation-induced protein S-glutathionylation (P-SSG) accounts for a phenotypic switch in human aortic valvular tissue, eventually leading to calcium deposition. Next, we tested whether countering this reactive oxygen species (ROS) surge would prevent these perturbations. Results: We employed state-of-the-art technologies, such as electron paramagnetic resonance (EPR), liquid chromatography-tandem mass spectrometry, imaging flow-cytometry, and live-cell imaging on human excised aortic valves and primary valve endothelial cells (VECs). We observed that a net rise in EPR-detected ROS emission marked the transition from fibrotic to calcific in human CAVS specimens, coupled to a progressive increment in P-SSG deposition. In human VECs (hVECs), treatment with 2-acetylamino-3-[4-(2-acetylamino-2-carboxyethylsulfanylthiocarbonylamino)phenylthiocarbamoylsulfanyl]propionic acid triggered highly oxidizing conditions prompting P-SSG accumulation, damaging mitochondria, and inducing endothelial nitric oxide synthase uncoupling. All the events conjured up in morphing these cells from their native endothelial phenotype into a damaged calcification-inducing one. As proof of principle, the use of the antioxidant N-acetyl-L-cysteine prevented these alterations. Innovation: Borne as a compensatory system to face excessive oxidative burden, with time, P-SSG contributes to the morphing of hVECs from their innate phenotype into a damaged one, paving the way to calcium deposition. Conclusion: Our data suggest that, in the human aortic valve, unremitted ROS emission along with a P-SSG build-up occurs and accounts, at least in part, for the morphological/functional changes leading to CAVS. Antioxid. Redox Signal. 37, 1051-1071.

Migraine in Patients Undergoing PFO Closure: Characterization of a Platelet-Associated Pathophysiological Mechanism: The LEARNER Study.

The association between migraine and patent foramen ovale (PFO) has been documented. We aimed to investigate platelet activation, prothrombotic phenotype, and oxidative stress status of migraineurs with PFO on 100 mg/day aspirin, before and 6 months after PFO closure. Data show that, before PFO closure, expression of the classical platelet activation markers is comparable in patients and aspirin-treated healthy subjects. Conversely, MHA-PFO patients display an increased prothrombotic phenotype (higher tissue factorpos platelets and microvesicles and thrombin-generation potential), sustained by an altered oxidative stress status. This phenotype, which is more controlled by P2Y12-blockade than by aspirin, reverted after PFO closure together with a complete migraine remission. (pLatelEts And MigRaine iN patEnt foRamen Ovale [LEARNER]; NCT03521193).

N-Acetylcysteine Regenerates In Vivo Mercaptoalbumin.

Human serum albumin (HSA) represents the most abundant plasma protein, with relevant antioxidant activity due to the presence of the sulfhydryl group on cysteine at position 34 (Cys34), the latter being one of the major target sites for redox-dependent modifications leading to the formation of mixed disulfide linkages with low molecular weight thiols. Thiolated forms of HSA (Thio-HSA) may be useful as markers of an unbalanced redox state and as a potential therapeutic target. Indeed, we have previously reported that albumin Cys34 can be regenerated in vitro by N-Acetylcysteine (NAC) through a thiol-disulfide breaking mechanism, with a full recovery of the HSA antioxidant and antiplatelet activities. With this case study, we aimed to assess the ability of NAC to regenerate native mercaptoalbumin (HSA-SH) and the plasma antioxidant capacity in subjects with redox unbalance, after oral and intravenous administration. A placebo-controlled crossover study, single-blinded, was performed on six hypertensive subjects, randomized into two groups, on a one-to-one basis with NAC (600 mg/die) or a placebo, orally and intravenously administered. Albumin isoforms, HSA-SH, Thio-HSA, and glutathione levels were evaluated by means of mass spectrometry. The plasma antioxidant activity was assessed by a fluorimetric assay. NAC, orally administered, significantly decreased the Thio-HSA levels in comparison with the pre-treatment conditions (T0), reaching the maximal effect after 60 min (-24.7 ± 8%). The Thio-HSA reduction was accompanied by a concomitant increase in the native HSA-SH levels (+6.4 ± 2%). After intravenous administration of NAC, a significant decrease of the Thio-HSA with respect to the pre-treatment conditions (T0) was observed, with a maximal effect after 30 min (-68.9 ± 10.6%) and remaining significant even after 6 h. Conversely, no effect on the albumin isoforms was detected with either the orally or the intravenously administered placebo treatments. Furthermore, the total antioxidant activity of the plasma significantly increased after NAC infusion with respect to the placebo (p = 0.0089). Interestingly, we did not observe any difference in terms of total glutathione corrected for hemoglobin, ruling out any effect of NAC on the intracellular glutathione and supporting its role as a disulfide-breaking agent. This case study confirms the in vitro experiments and demonstrates for the first time that NAC is able to regenerate mercaptoalbumin in vivo, allowing us to hypothesize that the recovery of Cys34 content can modulate in vivo oxidative stress and, hopefully, have an effect in oxidative-based diseases.

Association of Platelet Thromboxane Inhibition by Low-Dose Aspirin With Platelet Count and Cytoreductive Therapy in Essential Thrombocythemia.

Essential thrombocythemia (ET) is a myeloproliferative neoplasm characterized by enhanced platelet production and thrombotic complications. The inhibition of platelet cyclooxygenase (COX) activity by the standard once-daily aspirin is mostly incomplete due to accelerated thrombopoiesis. The phase II Aspirin Regimens in EsSential thrombocythemia (ARES) trial has recently compared the efficacy of once- vs. twice- or three-times daily low-dose aspirin in inhibiting platelet thromboxane (TX) A2 production, as reflected by serum (s) TXB2 measurements. The present substudy characterized the determinants of the highly variable response to the standard aspirin 100 mg once-daily regimen in fully compliant patients with ET and the effects of the experimental dosing regimens on response variability. By multivariable analysis, the platelet count (directly) and cytoreductive treatment (inversely) were significantly associated with sTXB2 values in 218 patients with ET. However, the platelet count positively correlated with sTXB2 in patients not being treated with cytoreductive drugs (ρ = 0.51, P < 0.01, n = 84), but not in patients on cytoreduction. Patients in the lowest sTXB2 quartile were older, more often on cytoreductive drugs, had lower platelet count and Janus-Associated Kinase2 (JAK2)-V617F allele frequency as compared with patients in the upper sTXB2 quartiles. After 2 weeks of a twice- or 3-times daily aspirin regimen, the association between the platelet count and sTXB2 became similar in cytoreduced and non-cytoreduced patients. In conclusion, the platelet count appears the strongest determinant of TXA2 inhibition by once-daily low-dose aspirin in ET, with different patterns depending of cytoreductive treatment. More frequent aspirin dosing restores adequate platelet inhibition and reduces interindividual variability, independently of cytoreduction.

[microRNAs as biological indicators of environmental and occupational exposure to asbestos]. / I microRNA come indicatori biologici di esposizione ambientale e occupazionale ad amianto.

Malignant mesothelioma is an aggressive cancer refractory to current therapies, the incidence of which is expected to rise in the next decades. Exposure to asbestos is a well known risk factor, as InternationalAgency for Research and Cancer (IARC) classified this compound as group I (carcinogenic to humans). The lack of tumor biomarkers for diagnosis and medical survey plays a fundamental role for the development of a universally accepted therapeutic approach. In this review we evaluated the mechanism of asbestos carcinogenesis by analyzing activated oncogenes, genetic predisposition, and SV40 infection as cofactors. Therefore, interest has focused on microRNAs, 19-25 nucleotide-long single-stranded RNAs that negatively regulate gene expression by modulating translational efficiency of target genes involved in numerous cellular processes including development, differentiation, proliferation, apoptosis, and stress response. The analysis revealed a differential expression of miRNAs between mesothelioma and mesothelial cells, suggesting their potential role as oncogenes or tumor suppressor genes in mesothelioma oncogenesis. We have also investigated the role of polymorphism in the etiology and pathogenesis of mesothelioma, in order to evaluate the association between disease linked to asbestos exposure andgenetic variability. The identification of dysregulated miRNAs or frequent genetic polymorphisms as potential diagnostic biomarkers or as prognostic factors for malignant mesothelioma could facilitate the surveillance procedure of subjects exposed to asbestos.

Effects of Mediterranean Diet or Low-Fat Diet on Blood Fatty Acids in Patients with Coronary Heart Disease. A Randomized Intervention Study.

The Mediterranean diet (MD) prevents cardiovascular disease by different putative mechanisms, including modifications in the blood fatty acid (FA) profile. Polytherapy for secondary cardiovascular prevention might mask the effect of MD on the FA profile. This study was aimed to assess whether MD, in comparison with a low-fat diet (LFD), favorably modifies the blood FA profile in patients with coronary heart disease (CHD) on polytherapy. One hundred and twenty patients with a recent history of coronary stenting, randomized to MD or to LFD, completed 3 months of this open-label dietary intervention study. Diet Mediterranean-ness was evaluated using the Mediterranean Diet Adherence Screener (MeDAS) score. Both diets significantly reduced saturated FA (p < 0.01). Putative favorable changes in total n-3 FA (p = 0.03) and eicosapentaenoic acid plus docosahexaenoic acid (EPA + DHA; p = 0.04) were significantly larger with MD than with LFD. At 3 months, in the whole cohort, the MeDAS score correlated inversely with palmitic acid (R = -0.21, p = 0.02), and with palmitoleic acid (R = -0.32, p = 0.007), and positively with total n-3 FA (R = 0.19, p = 0.03), EPA (R = 0.28, p = 0.002), and EPA + DHA (R = 0.21, p = 0.02). In CHD patients on polytherapy, both MD and LFD shift FA blood composition towards a healthier profile, with a more favorable effect of MD on omega-3 levels.