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Eyileten C, Jarosz-Popek J, Jakubik D, Gasecka A, Wolska M, Ufnal M, Postula M, Toma A, Lang IM, Siller-Matula JM. Plasma Trimethylamine-N-Oxide Is an Independent Predictor of Long-Term Cardiovascular Mortality in Patients Undergoing Percutaneous Coronary Intervention for Acute Coronary Syndrome. Front Cardiovasc Med 2021; 8:728724. [PMID: 34778397 PMCID: PMC8585769 DOI: 10.3389/fcvm.2021.728724] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 10/04/2021] [Indexed: 11/13/2022] Open
Abstract
To investigate the association of liver metabolite trimethylamine N-oxide (TMAO) with cardiovascular disease (CV)-related and all-cause mortality in patients with acute coronary syndrome (ACS) who underwent percutaneous coronary intervention. Our prospective observational study enrolled 292 patients with ACS. Plasma concentrations of TMAO were measured during the hospitalization for ACS. Observation period lasted seven yr in median. Adjusted Cox-regression analysis was used for prediction of mortality. ROC curve analysis revealed that increasing concentrations of TMAO levels assessed at the time point of ACS significantly predicted the risk of CV mortality (c-index=0.78, p < 0.001). The cut-off value of >4 μmol/L, labeled as high TMAO level (23% of study population), provided the greatest sum of sensitivity (85%) and specificity (80%) for the prediction of CV mortality and was associated with a positive predictive value of 16% and a negative predictive value of 99%. A multivariate Cox regression model revealed that high TMAO level was a strong and independent predictor of CV death (HR = 11.62, 95% CI: 2.26-59.67; p = 0.003). High TMAO levels as compared with low TMAO levels were associated with the highest risk of CV death in a subpopulation of patients with diabetes mellitus (27.3 vs. 2.6%; p = 0.004). Although increasing TMAO levels were also significantly associated with all-cause mortality, their estimates for diagnostic accuracy were low. High TMAO level is a strong and independent predictor of long-term CV mortality among patients presenting with ACS.
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Affiliation(s)
- Ceren Eyileten
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology (CEPT), Medical University of Warsaw, Warsaw, Poland
| | - Joanna Jarosz-Popek
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology (CEPT), Medical University of Warsaw, Warsaw, Poland
| | - Daniel Jakubik
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology (CEPT), Medical University of Warsaw, Warsaw, Poland
| | - Aleksandra Gasecka
- First Chair and Department of Cardiology, Medical University of Warsaw, Warsaw, Poland
| | - Marta Wolska
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology (CEPT), Medical University of Warsaw, Warsaw, Poland
| | - Marcin Ufnal
- Department of Experimental Physiology and Pathophysiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
- Marcin Ufnal
| | - Marek Postula
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology (CEPT), Medical University of Warsaw, Warsaw, Poland
| | - Aurel Toma
- Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna, Vienna, Austria
| | - Irene M. Lang
- Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna, Vienna, Austria
| | - Jolanta M. Siller-Matula
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology (CEPT), Medical University of Warsaw, Warsaw, Poland
- Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna, Vienna, Austria
- *Correspondence: Jolanta M. Siller-Matula
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Vaiserman A, Koliada A, Lushchak O, Castillo MJ. Repurposing drugs to fight aging: The difficult path from bench to bedside. Med Res Rev 2020; 41:1676-1700. [PMID: 33314257 DOI: 10.1002/med.21773] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 11/15/2020] [Accepted: 12/02/2020] [Indexed: 12/23/2022]
Abstract
The steady rise in life expectancy occurred across all developed countries during the last century. This demographic trend is, however, not accompanied by the same healthspan extension. This is since aging is the main risk factor for all age-associated pathological conditions. Therefore, slowing the rate of aging is suggested to be more efficient in preventing or delaying age-related diseases than treat them one by one, which is the common approach in a current pharmacological disease-oriented paradigm. To date, a variety of medications designed to treat particular pathological conditions have been shown to exhibit pro-longevity effects in different experimental models. Among them, there are many commonly used prescription and over-the-counter pharmaceuticals such as metformin, rapamycin, aspirin, statins, melatonin, vitamin antioxidants, etc. All of them are being increasingly investigated in preclinical and clinical trials with the aim of determine whether they have potential for extension of human healthspan. The results from these trials are frequently inconclusive and fall short of initial expectations, suggesting that innovative research ideas and additional translational steps are required to overcome obstacles for implementation of such approaches in clinical practice. In this review, recent advances and challenges in the field of repurposing widely used conventional pharmaceuticals to target the aging process are summarized and discussed.
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Affiliation(s)
| | | | - Oleh Lushchak
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine
| | - Manuel J Castillo
- Department of Medical Physiology, School of Medicine, University of Granada, Granada, Spain
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Masud R, Khan AUH, Anjum AF, Jawwad G, Azeem Z, Baqai HZ, Hashmi SN. The Connotation of Variances in the Risk Predictors, Medications, Homocysteine, and Homocysteine Pathway Gene Polymorphisms with CVA/Stroke. Glob Med Genet 2020; 7:113-120. [PMID: 33693444 PMCID: PMC7938795 DOI: 10.1055/s-0041-1722884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Cerebrovascular accidents (CVAs) are vascular multifactorial, multigenic ailments with intricate genetic, environmental risk influences. The present study aimed to establish affiliation of CVAs/stroke with blood parameters, differences in prescribed drugs consumption, and with differences in homocysteine pathway genes polymorphisms. The participants in study included controls n = 251, transient ischemic attack (TIA) patients n = 16, and stroke cases n = 122, respectively, (total participants, n = 389). The analyzed single nucleotide polymorphisms (SNPs) included C677T(rs1801133), A1298C(rs1801131) of methylene tetrahydrofolate reductase ( MTHFR ), A2756G(rs1805087) of methyl tetrahydrofolate homocysteine methyltransferase/methionine synthase ( MS ), and the A192G(rs662) of paraoxonase 1( PON1 ) genes, all validated by tetra-primer allele refractory mutation system polymerase chain reaction (T-ARMS-PCR). The insertion deletion (I/D; rs4646994) polymorphism in angiotensin converting enzyme ( ACE ) gene was analyzed using routine PCR. All studied traits were scrutinized through analysis of variance (ANOVA), and later through regression analysis. Through ANOVA and multiple comparison, there was association of CVA with serum homocysteine, cholesterol, and with diastolic blood pressure readings. When data was subjected to regression, serum homocysteine and diastolic blood pressure (significant through ANOVA), as well as two additional traits, high-density lipoproteins (HDL), and rs1801133 MTHFR SNP sustained statistical significance and noteworthy odds in relation to CVA and stroke. The ailments affecting cerebral vasculature are mutifactorial, whereby genes, proteins, and environmental cues all exert cumulative effects enhancing CVA risk. The current study emphasizes that SNPs and variation in circulating biomarkers can be used for screening purposes and for reviewing their effects in stroke/CVA-linked risk progression.
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Affiliation(s)
- Rizwan Masud
- Department of Physiology, CMH Kharian Medical College, Kharian, Pakistan
| | - Aleem Ul Haq Khan
- Department of Biochemistry, CMH Kharian Medical College, Kharian, Pakistan
| | - Aiman Farogh Anjum
- Department of Physiology, CMH Kharian Medical College, Kharian, Pakistan
| | - Ghazala Jawwad
- Department of Physiology, Rawal Institute of Health Sciences, Islamabad, Pakistan
| | - Zahid Azeem
- Department of Biochemistry, AJ&K Medical College, Muzaffarabad, AJ&K, Pakistan
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Gager GM, Jilma B, Winter M, Hengstenberg C, Lang IM, Toma A, Prüller F, Wallner M, Kolesnik E, von Lewinski D, Siller‐Matula JM. Ticagrelor and prasugrel are independent predictors of improved long-term survival in ACS patients. Eur J Clin Invest 2020; 50:e13304. [PMID: 32506444 PMCID: PMC7685125 DOI: 10.1111/eci.13304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/23/2020] [Accepted: 05/27/2020] [Indexed: 12/19/2022]
Abstract
AIM To investigate the long-term clinical benefit of dual antiplatelet therapy with potent P2Y12 inhibitors compared to clopidogrel in patients with acute coronary syndrome (ACS). METHODS In this prospective multicenter observational study, we enrolled 708 patients with ACS treated with clopidogrel (n = 137), ticagrelor (n = 260) or prasugrel (n = 311). Major adverse cardiac events (MACE; over 1 year) and long-term mortality (median: 5.6 years; interquartile range [IQR] 4.9-6.5 years) were assessed. Multiple electrode aggregometry (MEA) was used to measure adenosine diphosphate (ADP)- and arachidonic acid (AA)-induced platelet aggregation. RESULTS Type of P2Y12 inhibitor emerged as an independent predictor of long-term mortality and MACE: patients treated with potent platelet inhibitors prasugrel or ticagrelor were at lower risk for long-term mortality (adjusted hazard ratio [HR] = 0.44; 95% CI: 0.22-0.92; P = .028) or MACE (adjusted HR = 0.38; 95% CI: 0.20-0.73; P = .004) than those treated with clopidogrel independent from clinical risk factors. In contrast, the efficacy of clopidogrel decreased with increasing severity of ACS: platelet aggregation was 37% higher in patients with ST segment elevation myocardial infarction (STEMI) and 25% higher in patients with non-ST elevation myocardial infarction (non-STEMI) compared to patients with unstable angina (P = .039). Patients with diabetes achieved less potent ADP- and AA-induced platelet inhibition under clopidogrel, compared to patients without diabetes (P = .045; P = .030, respectively). CONCLUSION In the setting of ACS, treatment with ticagrelor or prasugrel reduced long-term mortality and 1-year MACE as compared to clopidogrel.
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Affiliation(s)
- Gloria M. Gager
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
- Department of Internal Medicine IIDivision of CardiologyMedical University of ViennaViennaAustria
| | - Bernd Jilma
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Max‐Paul Winter
- Department of Internal Medicine IIDivision of CardiologyMedical University of ViennaViennaAustria
| | - Christian Hengstenberg
- Department of Internal Medicine IIDivision of CardiologyMedical University of ViennaViennaAustria
| | - Irene M. Lang
- Department of Internal Medicine IIDivision of CardiologyMedical University of ViennaViennaAustria
| | - Aurel Toma
- Department of Internal Medicine IIDivision of CardiologyMedical University of ViennaViennaAustria
| | - Florian Prüller
- Clinical Institute of Medical and Chemical Laboratory DiagnosticsMedical University of GrazGrazAustria
| | - Markus Wallner
- Department of CardiologyMedical University of GrazGrazAustria
- Cardiovascular Research CenterLewis Katz School of MedicineTemple UniversityPhiladelphiaPAUSA
- Center for Biomarker Research in MedicineCBmed GmbHGrazAustria
| | - Ewald Kolesnik
- Department of CardiologyMedical University of GrazGrazAustria
| | | | - Jolanta M. Siller‐Matula
- Department of Internal Medicine IIDivision of CardiologyMedical University of ViennaViennaAustria
- Department of Experimental and Clinical PharmacologyCentre for Preclinical Research and Technology (CEPT)Medical University of WarsawWarsawPoland
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Bindu S, Mazumder S, Bandyopadhyay U. Non-steroidal anti-inflammatory drugs (NSAIDs) and organ damage: A current perspective. Biochem Pharmacol 2020; 180:114147. [PMID: 32653589 PMCID: PMC7347500 DOI: 10.1016/j.bcp.2020.114147] [Citation(s) in RCA: 677] [Impact Index Per Article: 169.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022]
Abstract
Owing to the efficacy in reducing pain and inflammation, non-steroidal anti-inflammatory drugs (NSAIDs) are amongst the most popularly used medicines confirming their position in the WHO's Model List of Essential Medicines. With escalating musculoskeletal complications, as evident from 2016 Global Burden of Disease data, NSAID usage is evidently unavoidable. Apart from analgesic, anti-inflammatory and antipyretic efficacies, NSAIDs are further documented to offer protection against diverse critical disorders including cancer and heart attacks. However, data from multiple placebo-controlled trials and meta-analyses studies alarmingly signify the adverse effects of NSAIDs in gastrointestinal, cardiovascular, hepatic, renal, cerebral and pulmonary complications. Although extensive research has elucidated the mechanisms underlying the clinical hazards of NSAIDs, no review has extensively collated the outcomes on various multiorgan toxicities of these drugs together. In this regard, the present review provides a comprehensive insight of the existing knowledge and recent developments on NSAID-induced organ damage. It precisely encompasses the current understanding of structure, classification and mode of action of NSAIDs while reiterating on the emerging instances of NSAID drug repurposing along with pharmacophore modification aimed at safer usage of NSAIDs where toxic effects are tamed without compromising the clinical benefits. The review does not intend to vilify these 'wonder drugs'; rather provides a careful understanding of their side-effects which would be beneficial in evaluating the risk-benefit threshold while rationally using NSAIDs at safer dose and duration.
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Affiliation(s)
- Samik Bindu
- Department of Zoology, Cooch Behar Panchanan Barma University, Cooch Behar, West Bengal 736101 India
| | - Somnath Mazumder
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4 Raja S.C. Mullick Road, Kolkata 700032, West Bengal, India
| | - Uday Bandyopadhyay
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4 Raja S.C. Mullick Road, Kolkata 700032, West Bengal, India; Division of Molecular Medicine, Bose Institute, P-1/12, CIT Rd, Scheme VIIM, Kankurgachi, Kolkata, West Bengal 700054 India.
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Liberale L, Montecucco F, Schwarz L, Lüscher TF, Camici GG. Inflammation and cardiovascular diseases: lessons from seminal clinical trials. Cardiovasc Res 2020; 117:411-422. [PMID: 32666079 DOI: 10.1093/cvr/cvaa211] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/29/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022] Open
Abstract
Inflammation has been long regarded as a key contributor to atherosclerosis. Inflammatory cells and soluble mediators play critical roles throughout arterial plaque development and accordingly, targeting inflammatory pathways effectively reduces atherosclerotic burden in animal models of cardiovascular (CV) diseases. Yet, clinical translation often led to inconclusive or even contradictory results. The Canakinumab Anti-inflammatory Thrombosis Outcome Study (CANTOS) followed by the Colchicine Cardiovascular Outcomes Trial (COLCOT) were the first two randomized clinical trials to convincingly demonstrate the effectiveness of specific anti-inflammatory treatments in the field of CV prevention, while other phase III trials-including the Cardiovascular Inflammation Reduction Trial one using methotrexate-were futile. This manuscript reviews the main characteristics and findings of recent anti-inflammatory Phase III trials in cardiology and discusses their similarities and differences in order to get further insights into the contribution of specific inflammatory pathways on CV outcomes. CANTOS and COLCOT demonstrated efficacy of two anti-inflammatory drugs (canakinumab and colchicine, respectively) in the secondary prevention of major adverse CV events (MACE) thus providing the first confirmation of the involvement of a specific inflammatory pathway in human atherosclerotic CV disease (ASCVD). Also, they highlighted the NOD-, LRR-, and pyrin domain-containing protein 3 inflammasome-related pathway as an effective therapeutic target to blunt ASCVD. In contrast, other trials interfering with a number of inflammasome-independent pathways failed to provide benefit. Lastly, all anti-inflammatory trials underscored the importance of balancing the risk of impaired host defence with an increase in infections and the prevention of MACE in CV patients with residual inflammatory risk.
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Affiliation(s)
- Luca Liberale
- Center for Molecular Cardiology, University of Zurich, 12 Wagistrasse, 8952 Schlieren, Switzerland.,First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, 6 viale Benedetto XV, 16132 Genoa, Italy
| | - Fabrizio Montecucco
- IRCCS Ospedale Policlinico San Martino Genoa - Italian Cardiovascular Network, 10 Largo Benzi, 16132 Genoa, Italy.,First Clinic of Internal Medicine, Department of Internal Medicine, Centre of Excellence for Biomedical Research (CEBR), University of Genoa, 6 viale Benedetto XV, 16132 Genoa, Italy
| | - Lena Schwarz
- Center for Molecular Cardiology, University of Zurich, 12 Wagistrasse, 8952 Schlieren, Switzerland
| | - Thomas F Lüscher
- Center for Molecular Cardiology, University of Zurich, 12 Wagistrasse, 8952 Schlieren, Switzerland.,Royal Brompton and Harefield Hospitals and Imperial College, London, UK
| | - Giovanni G Camici
- Center for Molecular Cardiology, University of Zurich, 12 Wagistrasse, 8952 Schlieren, Switzerland.,Department of Cardiology, University Heart Center, University Hospital Zurich, Rämistrasse 100, 8092 Zurich, Switzerland.,Department of Research and Education, University Hospital Zurich, Rämistrasse 100, 8092, Zurich, Switzerland
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Abstract
Previous studies reported an inverse association between healthy dietary patterns (such as Mediterranean diet) and the incidence of cardiovascular events. As the mechanism accounting for cardiovascular disease is prevalently due to the atherothrombosis, where a pivotal role is played by platelet activation, it would be arguable that diets with protective effects against cardiovascular disease exert an anti-atherothrombotic effect via inhibition of platelet activation. There are several and sparse typologies of studies, which investigated if single nutrients by diets recognized as having cardiovascular protection may exert an antithrombotic effect. The most investigated nutrients are key components of the Mediterranean diets such as fruits and vegetables, fish, olive oil, and wine; other diets with protective effects include nuts and cocoa. Here we summarize experimental and human interventional studies which investigated the antithrombotic effects of such nutrients in experimental models of thrombosis or analyzed biomarkers of clotting, platelet, and fibrinolysis activation in human; furthermore in vitro studies explored the underlying mechanism at level of several cell lines such as platelets or endothelial cells. In this context, we analyzed if nutrients affect simultaneously or separately clotting, platelet, and fibrinolysis pathways giving special attention to the relationship between oxidative stress and thrombosis as most nutrients are believed to possess antioxidant properties.
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Affiliation(s)
- Francesco Violi
- From the Department of Clinical Internal, Anesthesiologic and Cardiovascular Sciences, Sapienza University of Rome, Italy (F.V., D.P., P.P.).,Mediterranea Cardiocentro, Napoli, Italy (F.V., P.P., R.C.)
| | - Daniele Pastori
- From the Department of Clinical Internal, Anesthesiologic and Cardiovascular Sciences, Sapienza University of Rome, Italy (F.V., D.P., P.P.)
| | - Pasquale Pignatelli
- From the Department of Clinical Internal, Anesthesiologic and Cardiovascular Sciences, Sapienza University of Rome, Italy (F.V., D.P., P.P.).,Mediterranea Cardiocentro, Napoli, Italy (F.V., P.P., R.C.)
| | - Roberto Carnevale
- Mediterranea Cardiocentro, Napoli, Italy (F.V., P.P., R.C.).,Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Italy (R.C.)
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Abstract
PURPOSE OF REVIEW Perioperative management of antiplatelet agents (APAs) in the setting of noncardiac surgery is a controversial topic of balancing bleeding versus thrombotic risks. RECENT FINDINGS Recent data do not support a clear association between continuation or discontinuation of APAs and rates of ischemic events, bleeding complications, and mortality up to 6 months after surgery. Clinical factors, such as indication and urgency of the operation, time since stent placement, invasiveness of the procedure, preoperative cardiac optimization, underlying functional status, as well as perioperative control of supply-demand mismatch and bleeding may be more responsible for adverse outcome than antiplatelet management. SUMMARY Perioperative management of antiplatelet therapy (APT) should be individually tailored based on consensus among the anesthesiologist, cardiologist, surgeon, and patient to minimize both ischemic/thrombotic and bleeding risks. Where possible, surgery should be delayed for a minimum of 1 month but ideally for 3-6 months from the index cardiac event. If bleeding risk is acceptable, dual APT (DAPT) should be continued perioperatively; otherwise P2Y12 inhibitor therapy should be discontinued for the minimum amount of time possible and aspirin monotherapy continued. If bleeding risk is prohibitive, both aspirin and P2Y12 inhibitor therapy should be interrupted and bridging therapy may be considered in patients with high thrombotic risk.
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Lordan R, Tsoupras A, Zabetakis I. Platelet activation and prothrombotic mediators at the nexus of inflammation and atherosclerosis: Potential role of antiplatelet agents. Blood Rev 2020; 45:100694. [PMID: 32340775 DOI: 10.1016/j.blre.2020.100694] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 03/22/2020] [Accepted: 04/07/2020] [Indexed: 12/20/2022]
Abstract
Platelets are central to inflammation-related manifestations of cardiovascular diseases (CVD) such as atherosclerosis. Platelet-activating factor (PAF), thrombin, thromboxane A2 (TxA2), and adenosine diphosphate (ADP) are some of the key agonists of platelet activation that are at the intersection between a plethora of inflammatory pathways that modulate pro-inflammatory and coagulation processes. The aim of this article is to review the role of platelets and the relationship between their structure, function, and the interactions of their constituents in systemic inflammation and atherosclerosis. Antiplatelet therapies are discussed with a view to primary prevention of CVD by the clinical reduction of platelet reactivity and inflammation. Current antiplatelet therapies are effective in reducing cardiovascular risk but increase bleeding risk. Novel therapeutic antiplatelet approaches beyond current pharmacological modalities that do not increase the risk of bleeding require further investigation. There is potential for specifically designed nutraceuticals that may become safer alternatives to pharmacological antiplatelet agents for the primary prevention of CVD but there is serious concern over their efficacy and regulation, which requires considerably more research.
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Affiliation(s)
- Ronan Lordan
- Department of Biological Sciences, University of Limerick, Limerick, Ireland; Health Research Institute (HRI), University of Limerick, Limerick, Ireland; Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-5158, USA.
| | - Alexandros Tsoupras
- Department of Biological Sciences, University of Limerick, Limerick, Ireland; Health Research Institute (HRI), University of Limerick, Limerick, Ireland
| | - Ioannis Zabetakis
- Department of Biological Sciences, University of Limerick, Limerick, Ireland; Health Research Institute (HRI), University of Limerick, Limerick, Ireland
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Smith CJ, Perfetti TA. High-dose exposure to synthetic chemicals, hormones, or homeostatic substances in experimental animals or humans can induce artefactual pathology. TOXICOLOGY RESEARCH AND APPLICATION 2020. [DOI: 10.1177/2397847320940557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The maximum tolerated dose (MTD) provides the highest probability of a positive result in a toxicology bioassay. The assumption underlying the MTD in animal bioassays is that adverse effects at very high doses are qualitatively the same as those occurring at low doses. In contrast with the MTD, the optimal top dose in a toxicology animal study is the highest dose that does not produce a pathological end point that presents no risk at lower doses, for example, the dose below which cytotoxicity induces tumors in the absence of genotoxicity or other carcinogenic mechanisms. Normal concentrations or biological activity levels of many substances necessary for normal physiological function induce pathology when found at high levels. For example, the demonstration that ingestion of abnormally high levels of certain dietary fats can cause or exacerbate atherosclerosis in relevant animal models like rhesus macaques does not demonstrate that normal levels of these fats should be considered as toxic. Excessive estrogenic stimulation is associated with breast, ovarian, and endometrial cancers. This does not imply that normal age-appropriate levels of estrogen are toxic. Normal wound healing is associated with transforming growth factors beta 1 and 2. Excessive stimulation of fibroblasts by these growth factors results in hypertrophic scarring and keloid formation. An understanding of the mode of action of a test substance can facilitate the selection of dose levels much higher than those expected to be experienced by humans, but not beyond a dose level at which pathology is an experimental artefact of the high-dose level.
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