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1.
Biomolecular Consequences of Platelet Pathogen Inactivation Methods.
Feys, HB, Van Aelst, B, Compernolle, V
Transfusion medicine reviews. 2019;(1):29-34
Abstract
Pathogen inactivation (PI) for platelet concentrates (PC) is a fairly recent development in transfusion medicine that is intended to decrease infectious disease transmission from the donor to the receiving patient. Effective inactivation of viruses, bacteria and eukaryotic parasites adds a layer of safety, protecting the blood supply against customary and emerging pathogens. Three PI methods have been described for platelets. These are based on photochemical damage of nucleic acids which prevents replication of most infectious pathogens and contaminating donor leukocytes. Because platelets do not replicate, the collateral damage to platelet function is considered low to non-existing. This is disputable however because photochemistry is not specific for nucleic acids and significantly affects platelet biomolecules as well. The impact of these biomolecular changes on platelet function and hemostasis is not well understood, but is increasingly being studied. The results of these studies can help explain current and future clinical observations with PI platelets, including the impact on transfusion yield and bleeding. This review summarizes the biomolecular effects of PI treatment on platelets. We conclude that despite a comparable principle of photochemical inactivation, all three methods affect platelets in different ways. This knowledge can help blood banks and transfusion specialists to guide their choice when considering the implementation or clinical use of PI treated platelets.
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2.
Lipid Metabolism and Signaling in Platelet Function.
Paes, AMA, Gaspar, RS, Fuentes, E, Wehinger, S, Palomo, I, Trostchansky, A
Advances in experimental medicine and biology. 2019;:97-115
Abstract
Modern society has changed its diet composition, transitioning to a higher intake of saturated fat with a 50% increase of cardiovascular risk (CVD). Within the context of increased CVD, there is an induction of a prothrombotic phenotype mainly due to increased platelet reactivity as well as decreased platelet response to inhibitors. Platelets maintain haemostasis through both blood components and endothelial cells that secrete inhibitory or stimulatory molecules to regulate thrombus formation. There exist a correlation between platelets' polyunsaturated fatty acid (PUFA) and the increase in platelet reactivity. The aim of this chapter is to review the metabolism of the main PUFAs involved in platelet function associated with the role that their enzyme-derived oxidized metabolites exert in platelet function and fate. Finally, how lipid metabolism in the organism affect platelet aggregation and activation and the pharmacological modulation of these processes will also be discussed.
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3.
The long and winding road to pathogen reduction of platelets, red blood cells and whole blood.
Rebulla, P
British journal of haematology. 2019;(5):655-667
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Abstract
Pathogen reduction technologies (PRTs) have been developed to further reduce the current very low risks of acquiring transfusion-transmitted infections and promptly respond to emerging infectious threats. An entire portfolio of PRTs suitable for all blood components is not available, but the field is steadily progressing. While PRTs for plasma have been used for many years, PRTs for platelets, red blood cells (RBC) and whole blood (WB) were developed more slowly, due to difficulties in preserving cell functions during storage. Two commercial platelet PRTs use ultra violet (UV) A and UVB light in the presence of amotosalen or riboflavin to inactivate pathogens' nucleic acids, while a third experimental PRT uses UVC light only. Two PRTs for WB and RBC have been tested in experimental clinical trials with storage limited to 21 or 35 days, due to unacceptably high RBC storage lesion beyond these time limits. This review summarizes pre-clinical investigations and selected outcomes from clinical trials using the above PRTs. Further studies are warranted to decrease cell storage lesions after PRT treatment and to test PRTs in different medical and surgical conditions. Affordability remains a major administrative obstacle to PRT use, particularly so in geographical regions with higher risks of transfusion-transmissible infections.
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4.
Can mean platelet volume IndIcate HelIcobacter posItIvIty and severIty of gastrIc InflammatIon? An orIgInal study and revIew of the lIterature.
Akar, T
Acta clinica Croatica. 2019;(4):576-582
Abstract
Helicobacter pylori (H. pylori) is a common problem and a significant cause of chronic gastric inflammation. H. pylori, ongoing gastric inflammation and its severity are the most critical component of precursors of gastric cancer. Hypothetically, every chronic tissue injury activates platelets, and the mean platelet volume (MPV) reflects this action well. The potential relationship between H. pylori and platelet count has been shown before. However, there are few and conflicting papers about the relationship between MPV and H. pylori related chronic gastric inflammation and its severity. The study aimed to assess any potential relationship between MPV and presence of H. pylori, as well as the severity of chronic gastric inflammation. A total of 6890 endoscopic reports were initially evaluated, and a total of 218 dyspeptic patients having undergone upper endoscopy were included. Of these, 118 (54.2%) were H. pylori positive and 100 (45.8%) were H. pylori negative. At least four gastric biopsies were obtained and evaluated according to Sydney classification. Age, gender, hemoglobin, mean corpuscular volume, ferritin, serum iron and C-reactive protein, as well as endoscopic findings were also recorded. A p<0.05 was accepted as significant. The MPV and platelet count did not differ between H. pylori positive and H. pylori negative groups of patients (p>0.05). There were no differences and correlation between MPV and gastric inflammation severity according to Sydney classification (p>0.05). When stratifying MPV as <9.15 fL and >9.15 fL, there was no difference between H. pylori positive and H. pylori negative groups either (p>0.05). In this study, we found no relationship between MPV and presence of H. pylori or severity of gastric inflammation. Although there are still conflicting publications on this issue, in our opinion and according to the results of this study, MPV is not a suitable marker for evaluation of gastric inflammation severity, being H. pylori either positive or negative.
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5.
Polyphenols: Modulators of Platelet Function and Platelet Microparticle Generation?
Ed Nignpense, B, Chinkwo, KA, Blanchard, CL, Santhakumar, AB
International journal of molecular sciences. 2019;(1)
Abstract
Platelets and platelet microparticles (PMPs) play a key role in the pathophysiology of vascular disorders such as coronary artery disease and stroke. In atherosclerosis, for example, the disruption of the plaque exposes endogenous agonists such as collagen, which activates platelets. Platelet hyper-activation and the high levels of PMPs generated in such situations pose a thrombotic risk that can lead to strokes or myocardial infarctions. Interestingly, dietary polyphenols are gaining much attention due to their potential to mimic the antiplatelet activity of treatment drugs such as aspirin and clopidogrel that target the glycoprotein VI (GPVI)-collagen and cyclooxygenease-1 (COX-1)-thromboxane platelet activation pathways respectively. Platelet function tests such as aggregometry and flow cytometry used to monitor the efficacy of antiplatelet drugs can also be used to assess the antiplatelet potential of dietary polyphenols. Despite the low bioavailability of polyphenols, several in vitro and dietary intervention studies have reported antiplatelet effects of polyphenols. This review presents a summary of platelet function in terms of aggregation, secretion, activation marker expression, and PMP release. Furthermore, the review will critically evaluate studies demonstrating the impact of polyphenols on aggregation and PMP release.
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6.
Platelets: Peripheral Biomarkers of Dementia?
Akingbade, OES, Gibson, C, Kalaria, RN, Mukaetova-Ladinska, EB
Journal of Alzheimer's disease : JAD. 2018;(4):1235-1259
Abstract
Dementia continues to be the most burdening neurocognitive disorder, having a negative impact on the lives of millions. The search for biomarkers to improve the clinical diagnosis of dementia is ongoing, with the focus on effective use of readily accessible peripheral markers. In this review, we concentrate on platelets as biomarkers of dementia and analyze their potential as easily-accessible clinical biomarkers for various subtypes of dementia. Current platelet protein biomarkers that have been investigated for their clinical utility in the diagnosis of dementia, in particular Alzheimer's disease, include amyloid-β protein precursor (AβPP), the AβPP secretases (BACE1 and ADAM10), α-synuclein, tau protein, serotonin, cholesterol, phospholipases, clusterin, IgG, surface receptors, MAO-B, and coated platelets. Few of them, i.e., platelet tau, AβPP (particularly with regards to coated platelets) and secreted ADAM10 and BACE1 show the most promise to be taken forward into clinical setting to diagnose dementia. Aside from protein biomarkers, changes in factors such as mean platelet volume have the potential to play a very specific role in both the dementia diagnosis and prognosis. This review raises a number of research questions for consideration before application of the above biomarkers to routine clinical setting. It is without doubt that there is a need for more clarification on the effects of dementia on platelet morphology and protein content before these changes can be clinically applied as dementia biomarkers and explored further in differentiating distinct dementia subtypes.
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7.
Efficacy of platelet concentrates in pulpotomy - a systematic review.
Noor Mohamed, R, Basha, S, Al-Thomali, Y
Platelets. 2018;(5):440-445
Abstract
The main purpose of the present systematic review was to evaluate the efficacy of platelet concentrates in pulpotomy of human teeth. Our systematic search included Medline, Embase, CINAHL, PsycINFO, Scopus, key journals, and review articles; the date of the last search was July 30, 2017. We graded the methodological quality of the studies by Cochrane Risk of Bias tool. Four randomized controlled trails were included in the present systematic review. The number of study participants ranged from 28 to 50, with a mean of 45.5. The age of study participants ranged between 4 and 25 years. In three of the included studies, platelet-rich fibrin (autologous) was used and in one study lyophilized freeze-dried platelet (allogenic) was used as pulpotomy material. Calcium hydroxide and mineral trioxide aggregate were used in control groups. The quality assessment rated three studies as being of fair quality and one study as poor quality. Two of the included studies showed a 100% success of pulpotomy with platelet concentrates and two studies showed more than 80% of success, but the difference between control group and platelet concentrates group was not statistically significant. To conclude, the number of publications that met all inclusion criteria was found to be very limited and no significant difference was reported in the studies comparing platelet concentrates with other materials in pulpotomy. The present results point to the need for high-quality randomized controlled trials in further research.
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8.
The Human Carbonic Anhydrase II in Platelets: An Underestimated Field of Its Activity.
Jakubowski, M, Szahidewicz-Krupska, E, Doroszko, A
BioMed research international. 2018;:4548353
Abstract
Carbonic anhydrases constitute a group of enzymes that catalyse reversible hydration of carbon dioxide leading to the formation of bicarbonate and proton. The platelet carbonic anhydrase II (CAII) was described for the first time in the '80s of the last century. Nevertheless, its direct role in platelet physiology and pathology still remains poorly understood. The modulation of platelet CAII action as a therapeutic approach holds promise as a novel strategy to reduce the impact of cardiovascular diseases. This short review paper summarises the current knowledge regarding the role of human CAII in regulating platelet function. The potential future directions considering this enzyme as a potential drug target and important pathophysiological chain in platelet-related disorders are described.
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9.
[high on-treatment platelet reactivity in patients with chronic renal failure using acetylsalicylic acid].
Horyniecki, M, Łącka-Gaździk, B, Dworaczek, W, Śnit, M, Łabuz-Roszak, B
Wiadomosci lekarskie (Warsaw, Poland : 1960). 2017;(6 pt 1):1102-1107
Abstract
Cardiovascular diseases (CVD) are the most common cause of mortality in the world. Acetylsalicylic acid (ASA) is a widely used medicine in primary and secondary prevention of cardiovascular diseases. About 1-60% patients taking aspirin have high platelet reactivity (HOPR) despite aspirin treatment. HOPR is significantly more frequent in patients with chronic kidney disease (CKD) and it increases the risk of adverse cardiovascular events in these patients. The cause of HOPR in patients with CKD may be oxidative stress and inflammation. To the risk factors belong diabetes, female sex or decreased HDL cholesterol level.
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10.
Platelet-Mediated Modulation of Fibrinolysis.
Whyte, CS, Mitchell, JL, Mutch, NJ
Seminars in thrombosis and hemostasis. 2017;(2):115-128
Abstract
Platelets are crucial to the hemostatic response. Their role in coagulation is well documented and they have been considered for some time to promote resistance of thrombi to fibrinolysis. Platelets confer resistance to lysis by promoting clot retraction of the immediate fibrin network and through release of plasminogen activator inhibitor-1 from their α-granules. However, recent developments in the field indicate that the role of platelets in fibrinolysis is much more diverse. Indeed, novel studies suggest that platelets form different subpopulations upon activation that play varied roles in regulating hemostasis. Likewise the developments in our understanding of thrombus formation, architecture, and changes in fibrin deposition and composition suggest that these different subpopulations of platelets may populate distinct areas within thrombi and potentially dictate the local hemostatic balance in these areas. This review will discuss the diverse roles of platelets in fibrinolysis and highlight the recent developments in the field and the contribution of both the intracellular pool of modulators as well as the membrane surface in regulating these processes.