P5454PCSK9 as a predictor of cardiovascular events in atrial fibrillation: role of platelet activation

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
R Carnevale ◽  
V Cammisotto ◽  
C Nocella ◽  
S Bartimoccia ◽  
D Pastori ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Atrial Fibrillation ◽  
Platelet Activation ◽  
Plasma Levels ◽  
Cardiovascular Events ◽  
In Vitro Study ◽  
H2o2 Production ◽  
Markers Of Oxidative Stress

Abstract Background High circulating levels of proprotein convertase subtilisin/kexin 9 (PCSK9) were shown to be predictive of cardiovascular events (CVEs) in patients with atrial fibrillation (AF). Because high PCSK9 plasma levels were significantly correlated with 11-dehydro-thromboxane B2 (11-dh-TxB2), a marker of platelet activation, it is conceivable to hypothesize a direct effect of PCSK9 on platelet activation but the mechanism is still unclear. Purpose We evaluated the association between PCSK9 and platelet activation in FA patients and investigate the possible molecular mechanism involved. Methods According to our previous prospective study, we conducted a post-hoc analysis including 50 patients with baseline PCSK9 below and 50 above the median value of 1200pg/ml. The two groups were balanced for age and sex. In vivo platelet activation was assessed by aggregation (PA), recruitment, plasma thromboxane B2 (TxB2) formation and sPselectin levels. As markers of oxidative stress we used sNox2-dp, H2O2 production, urinary isoprostanes and oxLDL. To asses the role of PCSK9 in platelet activation, we performed an in vitro study with platelets from healthy subjects (n=5) added with PCSK9 concentrations achievable in human circulation (1000pg/ml and 2000pg/ml) measuring PA, TxB2, isoprostanes production, Nox2 activation, H2O2 production, oxLDL, p38, p47 and PLA2 phosphorylation. Results We observed an increased of platelet activation and oxidative stress in patients with PCSK9 levels above median (1200pg/ml) compared to those below (p<0.05). A significant correlation between plasma levels of PCSK9 and markers of platelet activation and markers of oxidative stress were found. In vitro study demonstrated that PCSK9, at the concentration similar to that of patients with CVEs, was able to increase platelet activation act by binding oxLDL receptor. PCSK9 dependent platelet activation is mediated by p47 phosphorylation, a key step in Nox2 activation and is mediated by the PLA2 phosporylation. Conclusions PCSK9, at concentration achievable in patients with CVEs, increased platelet aggregation via oxLDL receptor with a pathway involving Nox2 activation.

scholarly journals HIF-1α Activation Promotes Luteolysis by Enhancing ROS Levels in the Corpus Luteum of Pseudopregnant Rats

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zonghao Tang ◽  
Jiajie Chen ◽  
Zhenghong Zhang ◽  
Jingjing Bi ◽  
Renfeng Xu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Corpus Luteum ◽  
Cell Apoptosis ◽  
In Vitro Study ◽  
Luteal Cell ◽  
Independent Manner ◽  
Luteal Regression ◽  
Luteal Cells

The increase of oxidative stress is one of the important characteristics of mammalian luteal regression. Previous investigations have revealed the essential role of reactive oxygen species (ROS) in luteal cell death during luteolysis, while it is unknown how ROS is regulated in this process. Considering the decrease of blood flow and increase of PGF2α during luteolysis, we hypothesized that the HIF-1α pathway may be involved in the regulation of ROS in the luteal cell of the late corpus luteum (CL). Here, by using a pseudopregnant rat model, we showed that the level of both HIF-1α and its downstream BNIP3 was increased during luteal regression. Consistently, we observed the increase of autophagy level during luteolysis, which is regulated in a Beclin1-independent manner. Comparing with early (Day 7 of pseudopregnancy) and middle CL (Day 14), the level of ROS was significantly increased in late CL, indicating the contribution of oxidative stress in luteolysis. Inhibition of HIF-1α by echinomycin (Ech), a potent HIF-1α inhibitor, ameliorated the upregulation of BNIP3 and NIX, as well as the induction of autophagy and the accumulation of ROS in luteal cells on Day 21 of pseudopregnancy. Morphologically, Ech treatment delayed the atrophy of the luteal structure at the late-luteal stage. An in vitro study indicated that inhibition of HIF-1α can also attenuate PGF2α-induced ROS and luteal cell apoptosis. Furthermore, the decrease of cell apoptosis can also be observed by ROS inhibition under PGF2α treatment. Taken together, our results indicated that HIF-1α signaling is involved in the regression of CL by modulating ROS production via orchestrating autophagy. Inhibition of HIF-1α could obviously hamper the apoptosis of luteal cells and the process of luteal regression.

scholarly journals Serum Fetuin-B Levels Are Elevated in Women with Metabolic Syndrome and Associated with Increased Oxidative Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Shiyao Xue ◽  
Hongdong Han ◽  
Shunli Rui ◽  
Mengliu Yang ◽  
Yizhou Huang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Healthy Subjects ◽  
Bioinformatics Analysis ◽  
Cholesterol Metabolism ◽  
In Vitro Study ◽  
Multivariate Regression Analysis ◽  
Regulatory Factors ◽  
Triglyceride Content

Previous studies on serum fetuin-B (fetuin-like protein IRL685) have investigated its association with T2DM; however, the reason for the variation in serum fetuin-B and its regulatory factors in metabolic disease remain unclear. Here, we evaluated serum fetuin-B levels in women with newly diagnosed MetS and performed multiple interventions to investigate the role of fetuin-B in the pathogenesis of MetS. Serum fetuin-B levels were assessed using ELISA. Bioinformatics analysis was performed to analyze fetuin-B-related genes and signaling pathways. Additionally, oxidative stress parameters were measured in the in vitro study. For subgroup analyses, we performed EHC, OGTT, and treatment with a GLP-1RA to investigate the regulatory factors of serum fetuin-B. We found that in comparison with healthy subjects, serum fetuin-B levels were markedly increased in women with MetS. Further, serum fetuin-B showed a positive correlation with WHR, FAT%, TG, FBG, HbA1c, FIns, HOMA-IR, VAI, and LAP. Bioinformatics analysis revealed that most fetuin-B-related core genes were involved in cholesterol metabolism and fat decomposition. Consistent with this finding, multivariate regression analysis showed that triglyceride content and WHR were independently associated with serum fetuin-B. We also observed that serum fetuin-B levels were markedly elevated in healthy subjects after glucose loading and in women with MetS during EHC. In vitro, overexpression of fetuin-B promoted oxidative stress in HepG2 cell. After 6 months of treatment with a GLP-1RA, serum fetuin-B levels in women with MetS decreased following an improvement in metabolism and insulin sensitivity. Therefore, serum fetuin-B is associated with MetS, which may serve as a biomarker of oxidative stress. This trial is registered with ChiCTR-OCC-11001422.

In Vitro Study of Antioxidant Activity of Serum and Plasma Samples As Well As Glutathione Exposed to Various Exogenous Stress Factors

2021 ◽  
Author(s):  
Małgorzata Olszowy-Tomczyk ◽  
Łukasz Paprotny ◽  
Agnieszka Celejewska ◽  
Dorota Szewczak ◽  
Dorota Wianowska
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Activity ◽  
Antioxidant Properties ◽  
In Vitro Study ◽  
Stress Factors ◽  
Plasma Samples ◽  
Serum Samples ◽  
Exogenous Stress

Abstract The imbalance between the production of Reactive Oxygen Species (ROS) and their sequestration promotes the formation of so-called oxidative stress conditions which are considered crucial in the aging process and development of many human diseases. Glutathione plays an essential role in the antioxidative barricade against ROS. Its role in the detoxification process of xenobiotics and carcinogen is also known. However, there are no comparative studies on the antioxidant properties of both biological samples and glutathione as well as the change in these properties as a result of exposure to various stress factors. This paper fills this gap comparing the antioxidant activity of serum and plasma samples of the known glutathione content with the activity of glutathione itself assessed by the different methods. In addition, it reveals a significant role of environmental xenobiotics in oxidative stress and differentiates the stress induced by different groups of drugs, among which the greatest one has been demonstrated for antiarrhythmic drugs and cytostatics. More importantly, it proves that human plasma is more resistant to stress factors and N-acetylcysteine clearly promotes the extension of antioxidant properties of both the plasma and serum samples. The latter conclusion is consistent with the implied preventive and/or supportive action of this drug against SARS-CoV-2.

scholarly journals The Key Role of Uric Acid in Oxidative Stress, Inflammation, Fibrosis, Apoptosis, and Immunity in the Pathogenesis of Atrial Fibrillation

2021 ◽  
Vol 8 ◽  
Author(s):  
Yawen Deng ◽  
Fei Liu ◽  
Xiaolei Yang ◽  
Yunlong Xia
Keyword(s):  
Oxidative Stress ◽  
Atrial Fibrillation ◽  
Risk Factor ◽  
Clinical Evidence ◽  
Scientific Evidence ◽  
Critical Role ◽  
Adverse Outcomes

Atrial fibrillation (AF) is a highly prevalent cardiac arrhythmia that leads to numerous adverse outcomes including stroke, heart failure, and death. Hyperuricemia is an important risk factor that contributes to atrium injury and AF, but the underlying molecular mechanism remains to be elucidated. In this review, we discussed the scientific evidence for clarifying the role of hyperuricemia in the pathogenesis of AF. Experimental and Clinical evidence endorse hyperuricemia as an independent risk factor for the incidence of AF. Various in vivo and in vitro investigations showed that hyperuricemia might play a critical role in the pathogenesis of AF at different UA concentrations through the activation of oxidative stress, inflammation, fibrosis, apoptosis, and immunity.

scholarly journals The antioxidant effects of melatonin in blood platelets during exposure to electromagnetic radiation – an in vitro study

2021 ◽  
Vol 75 (1) ◽  
pp. 889-895
Author(s):  
Małgorzata Lewicka ◽  
Magdalena Zawadzka ◽  
Gabriela Henrykowska ◽  
Maciej Rutkowski ◽  
Andrzej Buczyński
Keyword(s):  
Oxidative Stress ◽  
Electromagnetic Radiation ◽  
Blood Platelets ◽  
In Vitro Study ◽  
Oxygen Metabolism ◽  
Protective Role ◽  
Negative Effect ◽  
Antioxidant Effects

Abstract Objectives The article presents the results of an in vitro study aimed at identifying changes in parameters of oxidative stress – concentration of malondialdehyde (MDA), enzymatic activity of superoxide dismutase (SOD-1) and protective antioxidant role of melatonin (MLT) during the exposure of blood platelets to electromagnetic radiation (EMR) emitted by monitors. Methods Platelets were exposed to an EMR for 30- and 60 min. generated by monitors (1 kHz frequency, 220 V/m intensity). In each sample the level of SOD-1 activity and concentration of MDA were determined. Results The MDA concentration increased significantly after 30-and 60-min. irradiation, as compared to control values (2.53 vs 1.36; 3.64 vs 1.36 nmol/109 blood platelets) and after the addition of MLT it decreased (2.53 vs 1.55; 3.64 vs 1.12 nmol/109 blood platelets). The activity of SOD-1 increased significantly compared to control values after 30 min. and 60 min. of exposure to EMR (1.97vs 0.75; 2.08 vs 0.75 U/g of protein), and significantly decreased after the addition of MLT only in samples exposed for 60 min. (2.08 vs 0.95 U/g of protein). Discussion The results demonstrated the possibly negative effect of EMR on oxygen metabolism of blood platelets and indicated a possible protective role of melatonin in this process.

scholarly journals Digoxin and Platelet Activation in Patients With Atrial Fibrillation: In Vivo and In Vitro Study

2018 ◽  
Vol 7 (22) ◽  
Author(s):  
Daniele Pastori ◽  
Roberto Carnevale ◽  
Cristina Nocella ◽  
Simona Bartimoccia ◽  
Marta Novo ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Platelet Activation ◽  
In Vitro Study ◽  
Vitro Study

scholarly journals PCSK9 Regulates Nox2-Mediated Platelet Activation via CD36 Receptor in Patients with Atrial Fibrillation

Antioxidants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 296 ◽  
Author(s):  
Vittoria Cammisotto ◽  
Daniele Pastori ◽  
Cristina Nocella ◽  
Simona Bartimoccia ◽  
Valentina Castellani ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Risk Factors ◽  
Atrial Fibrillation ◽  
Platelet Activation ◽  
Cardiovascular Events ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Oxidized Low Density Lipoprotein ◽  
Cd36 Receptor

Background: High levels of proprotein convertase subtilisin/kexin 9 (PCSK9) is predictive of cardiovascular events (CVEs) in atrial fibrillation (AF). We hypothesized that PCSK9 may directly induce platelet activation (PA). Methods: We measured platelet aggregation, recruitment, Thromboxane B2 (TxB2) formation and soluble P-selectin levels as markers of PA and soluble Nox2-derived peptide (sNox2-dp), H2O2, isoprostanes and oxidized Low-Density-Lipoprotein (oxLDL) to analyze oxidative stress (OS) in 88 patients having PCSK9 values < (n = 44) or > (n = 44) 1.2 ng/mL, balanced for age, sex and cardiovascular risk factors. Furthermore, we investigated if normal (n = 5) platelets incubated with PCSK9 (1.0–2.0 ng/mL) alone or with LDL (50 µg/mL) displayed changes of PA, OS and down-stream signaling. Results: PA and OS markers were significantly higher in patients with PCSK9 levels > 1.2 ng/mL compared to those with values < 1.2 ng/mL (p < 0.001). Levels of PCSK9 significantly correlated with markers of PA and OS. Platelets incubation with PCSK9 increased PA, OS and p38, p47 and Phospholipase A2 (PLA2) phosphorylation. These changes were amplified by adding LDL and blunted by CD36 or Nox2 inhibitors. Co-immunoprecipitation analysis revealed an immune complex of PCSK9 with CD36. Conclusions: We provide the first evidence that PCSK9, at concentration found in the circulation of AF patients, directly interacts with platelets via CD36 receptor and activating Nox2: this effect is amplified in presence of LDL.

Non-Nutritive Bioactive Food Constituents of Plants: Tocopherols (Vitamin E)

2003 ◽  
Vol 73 (2) ◽  
pp. 89-94 ◽  
Author(s):  
Elmadfa ◽  
Wagner
Keyword(s):  
Oxidative Stress ◽  
Human Liver ◽  
Alpha Tocopherol ◽  
Published Data ◽  
Direct Relation ◽  
Culture Studies ◽  
Ldl Particles ◽  
Markers Of Oxidative Stress

An increasing body of data, especially the in vitro and cell culture studies support protecting effects of tocopherols. They indicate that there is a selective tocopherol transport in the human liver with a higher affinity for a-tocopherol, however, they also show that in food, gamma- and delta-tocopherol are a more potent antioxidant than alpha-tocopherol. Tocopherols as alpha group are the key antioxidants in human cell membranes and are also important in protecting the LDL particles. These LDL particles and other similar intermediate markers of oxidative stress show a good response to tocopherol intakes. Published data underline the role of tocopherols as protecting agents against oxidative stress. They therefore allow the assumption that alpha-tocopherol is probably effective in preventing atherosclerosis, although no proven direct relation to the outcome of the disease itself exists.

Mechanisms of digoxin-related platelet activation in atrial fibrillation patients: In vivo and in vitro study

2018 ◽  
Vol 275 ◽  
pp. e95-e96
Author(s):  
D. Pastori ◽  
c. Nocella ◽  
r. Carnevale ◽  
v. Cammisotto ◽  
f. Violi ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Platelet Activation ◽  
In Vitro Study ◽  
Vitro Study
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