| 1. |
- Bergemalm, Daniel, 1977-, et al.
(författare)
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Platelet proteome and function in X-linked thrombocytopenia with thalassemia and in silico comparisons with gray platelet syndrome
- 2021
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Ingår i: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 1592-8721 .- 0390-6078. ; 106:11
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Tidskriftsartikel (refereegranskat)abstract
- In X-linked thrombocytopenia with thalassemia (XLTT; OMIM 314050), caused by the mutation p.R216Q in exon 4 of the GATA1 gene, male hemizygous patients display macrothrombocytopenia, bleeding diathesis and a β-thalassemia trait. Herein, we describe findings in two unrelated Swedish XLTT families with a bleeding tendency exceeding what is expected from the thrombocytopenia. Blood tests revealed low P-PAI-1 and P-factor 5, and elevated S-thrombopoietin levels. Transmission electron microscopy showed diminished numbers of platelet α- and dense granules. The proteomes of isolated blood platelets from 5 male XLTT patients, compared to 5 gender- and age matched controls, were explored. Quantitative mass spectrometry showed alterations of 83 proteins (fold change ≥±1.2, q< .05). Of 46 downregulated proteins, 39 were previously reported to be associated with platelet granules. Reduced protein levels of PTGS1 and SLC35D3 were validated in megakaryocytes of XLTT bone marrow biopsies by immunohistochemistry. Platelet function testing by flow cytometry revealed low dense- and α-granule release and fibrinogen binding in response to ligation of receptors for ADP, the thrombin receptor PAR4 and the collagen receptor GPVI. Significant reductions of a number of α-granule proteins overlapped with a previous platelet proteomics investigation in the inherited macrothrombocytopenia gray platelet syndrome (GPS). In contrast, Ca2+ transporter proteins that facilitate dense granule release were downregulated in XLTT but upregulated in GPS. Ingenuity Pathway Analysis showed altered Coagulation System and Protein Ubiquitination pathways in the XLTT platelets. Collectively, the results revealed protein and functional alterations affecting platelet α- and dense granules in XLTT, probably contributing to bleeding.
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| 2. |
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| 3. |
- Törnudd, Mattias, et al.
(författare)
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Quantification of platelet function : a comparative study of venous and arterial blood using a novel flow cytometry protocol
- 2022
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Ingår i: Platelets. - Abingdon, United Kingdom : Taylor & Francis. - 0953-7104 .- 1369-1635. ; 33:6, s. 926-934
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Tidskriftsartikel (refereegranskat)abstract
- Studies of platelet function in surgical patients often involve both arterial and venous sampling. Possible effects of different sampling sites could be important, but have not been thoroughly investigated. We aimed to compare platelet function in arterial and venous blood samples using a novel flow cytometry protocol and impedance aggregometry. Arterial and venous blood was collected before anesthesia in 10 patients undergoing cardiac surgery of which nine was treated with acetylsalicylic acid until the day before surgery. Flow cytometry included simultaneous analysis of phosphatidylserine exposure, active conformation of the fibrinogen receptor (PAC-1 binding), alpha-granule and lysosomal release (P-selectin and LAMP-1 exposure) and mitochondrial membrane integrity. Platelets were activated with ADP or peptides activating thrombin receptors (PAR1-AP/PAR4-AP) or collagen receptor GPVI (CRP-XL). Leukocyte-platelet conjugates and P-selectin exposure were evaluated immediately in fixated samples. For impedance aggregometry (Multiplate (R)), ADP, arachidonic acid, collagen and PAR1-AP (TRAP) were used as activators. Using impedance aggregometry and in 27 out of 37 parameters studied with flow cytometry there was no significant difference between venous and arterial blood sampling. Arterial blood showed more PAC-1 positive platelets when activated with PAR1-AP or PAR4-AP and venous blood showed more monocyte-platelet and neutrophil-platelet conjugates and higher phosphatidylserine exposure with CRP-XL alone and combined with PAR1-AP or PAR4-AP. We found no differences using impedance aggregometry. In conclusion, testing of platelet function by flow cytometry and impedance aggregometry gave comparable results for most of the studied parameters in venous and arterial samples. Flow cytometry identified differences in PAC-1 binding when activated with PAR1-AP, exposure of phosphatidyl serine and monocyte/neutrophil-platelet conjugates, which might reflect differences in blood sampling technique or in flow conditions in this patient cohort with coronary artery disease. These differences might be considered when comparing data from different sample sites, but caution should be exercised if a different protocol is used or another patient group is studied.
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| 4. |
- Banerjee, Meenakshi, et al.
(författare)
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Prospective, International, Multisite Comparison of Platelet Isolation Techniques for Genome-Wide Transcriptomics : Communication from the SSC of the ISTH
- 2024
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Ingår i: Journal of Thrombosis and Haemostasis. - : John Wiley & Sons. - 1538-7933 .- 1538-7836.
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide platelet transcriptomics is increasingly used to uncover new aspects of platelet biology and as a diagnostic and prognostic tool. Nevertheless, platelet isolation methods for transcriptomic studies are not standardized, introducing challenges for cross-study comparisons, data integration, and replication. In this prospective multicenter study, called "Standardizing Platelet Transcriptomics for Discovery, Diagnostics, and Therapeutics in the Thrombosis and Hemostasis Community (STRIDE)" by the ISTH SSCs, we assessed how three of the most commonly used platelet isolation protocols influence metrics from next-generation bulk RNA sequencing and functional assays. Compared with washing alone, more stringent removal of leukocytes by anti-CD45 beads or PALLTM filters resulted in a sufficient quantity of RNA for next-generation sequencing and similar quality of RNA sequencing metrics. Importantly, stringent removal of leukocytes resulted in the lower relative expression of known leukocyte-specific genes and the higher relative expression of known platelet-specific genes. The results were consistent across enrolling sites, suggesting the techniques are transferrable and reproducible. Moreover, all three isolation techniques did not influence basal platelet reactivity, but agonist-induced integrin αIIbβ3 activation is reduced by anti-CD45 bead isolation compared to washing alone. In conclusion, the isolation technique chosen influences genome-wide transcriptional and functional assays in platelets. These results should help the research community make informed choices about platelet isolation techniques in their own platelet studies.
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| 5. |
- Befekadu, Rahel, 1968-, et al.
(författare)
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Dynamic Changes in Pentraxin-3 and Neprilysin in ST Segment Elevation Myocardial Infarction
- 2022
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Ingår i: Biomedicines. - : MDPI. - 2227-9059. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Pentraxin-3 (PTX3) and neprilysin have been associated with increased morbidity and mortality in chronic inflammatory disease and heart failure, but these biomarkers have been studied less in patients with ST segment elevation myocardial infarction (STEMI). We investigated the dynamic changes in these biomarkers, as well as the well-known C-reactive protein (CRP), in STEMI patients. PTX3, neprilysin and CRP were measured in samples from 165 STEMI patients, collected at the acute stage, 1-3 days after and 3 months after percutaneous coronary intervention (PCI), and from 40 healthy donors. Patient survival was followed for approximately 8 years after the PCI. As compared with samples from healthy donors, plasma levels of CRP and PTX3 were significantly increased in the acute samples and 1-3 days after PCI, but not at 3 months. CRP levels peaked at 1-3 days, while PTX3 was similarly high in both acute and 1-3 days samples. For neprilysin, no significant differences were observed at the group level. We found no significant differences when comparing patients with patent versus occluded culprit vessels or between patients having a thrombus aspiration or not. However, we found a significant reduction in survival for individuals with PTX3 above the median, both for samples collected at the acute stage and 1-3 days after PCI (p = 0.0001 and p = 0.0008, respectively). For CRP, no significant differences were observed using this approach, but patients above the reference range for healthy donors in the acute samples showed significantly lower survival (p = 0.0476). Conclusions: Survival analysis suggests that PTX3 might be a promising marker to predict mortality in this patient population.
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| 6. |
- Befekadu, Rahel, 1968-, et al.
(författare)
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Levels of soluble tumor necrosis factor receptor 1 and 2 are associated with survival after ST segment elevation myocardial infarction
- 2022
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The soluble tumor necrosis factor receptors (sTNFR1 and sTNFR2) are suggested to play dual roles on physiological and pathophysiological actions of TNF-α. The aim of this study was to investigate the dynamic changes of these biomarkers in patients with ST-segment elevation myocardial infarction (STEMI). Blood was collected from 165 STEMI patients at admission, 1-3 days and 3 months after percutaneous coronary intervention (PCI) and from 40 healthy blood donors. sTNFR1 and sTNFR2 were measured with ELISA. The plasma levels of both sTNFR1 and sTNFR2 were significantly higher than in healthy donors at all three time points. We found no significant differences in sTNFR1 or sTNFR2 when comparing patients with patent versus occluded culprit vessels, or between patients having a thrombus aspiration or not. Survival analysis was performed comparing patients with levels of biomarkers above and below the median values at that time point. We found significant differences in survival for sTNFR2 in acute samples (p = 0.0151) and for both sTNFR1 and sTNFR2 in samples 1-3 days after PCI (p = 0.0054 and p = 0.0003, respectively). Survival analyses suggest that sTNFR1 or sTNFR2 could be promising markers to predict mortality in STEMI patients after PCI.
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| 7. |
- Befekadu Wodajo, Rahel, 1968-
(författare)
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Analysis of new biomarkers and their kinetics in connection with ST-elevation myocardial infarction and percutaneous coronary intervention
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis studies different biomarkers in a cohort of patients suffering from ST-elevation myocardial infarction (STEMI) who underwent Percutaneous coronary intervention (PCI) in Örebro in 2011-2012. Blood samples were collected at three time points, at the arrival at the hospital, 1-3 days after PCI and for a smaller group of patients also 3 months after PCI. The study is a sub-study of the TASTE study, so half of the patients were also randomized to thrombus aspiration in conjunction with their PCI. For all patients, it was also recorded whether the culprit coronary vessel was totally occluded or partially patent. In total, there are samples from 165 patients, but not all markers have been measured in all patients, and 3-month samples are only available from those who had their follow-up in Örebro. The plasma levels of the biomarkers have also been measured in plasma from blood donors for comparison. In March 2019, a follow-up was made of the patients' survival, and the time of death was noted in cases where this had occurred.The markers studied are the lysosome protein Cathepsin S (Cat-S), the platelet granule protein thrombospondin 1 (TSP-1), the pentraxins C-reactive protein (CRP) and pentraxin 3 (PTX3), the endopeptidase neprilysin, the soluble forms of TNF-receptor 1 and 2 (sTNFR1 and sTNFR2), markers showing activation of the lectin pathway for complement activation (MASP-1/AT, MASP-1/C1-INH, MASP-2/C1-INH, MASP-2/AT) and common activation markers for complement activation (C3a and sC5b-9).In summary, the thesis shows that the plasma levels of all markers, except neprilysin and sC5b-9, are elevated at the time of arrival compared to healthy blood donors. Neprilysin is at the same level, and sC5b-9 is lower compared to blood donors. 1-3 days after PCI, the levels for CRP, sTNFR1 and sC5b-9 have risen strongly (>50%) compared to the levels at arrival. MASP-1/AT and MASP-2/AT have fallen moderately (about 50%), Cat-S and TSP-1 have decreased strongly, while the remaining markers are relatively similar to the levels at arrival (± 25%). The levels for CRP, PTX3, sTNFR1, sTNFR2 and neprilysin decreased even further between 1-3 days and 3 months, sC5b-9 rises slightly while the other markers remain at roughly the same levels. At 3 months, most markers still show higher levels compared to corresponding levels in blood donors, only MASP-2/C1-INH has the same level, while neprilysin is slightly lower and TSP-1 much lower compared to blood donors (the latter presumably an effect of ongoing medication with platelet inhibitors in the patients). No relevant differences were observed between patients with and without thrombus aspiration, and few differences were seen between patients with occluded or partially patent vessels. This may indicate that these factors were of minor importance for the levels of the analyzed markers. In contrast, analysis of survival showed that individuals with plasma levels above the median value for PTX3, sTNFR1 and sTNFR2 at admission and/or at 1-3 days had a significantly increased mortality compared to those with levels below the median value, which indicates that these markers could be interesting for further studies in a material where also analysis of possible interfering factors can be implemented.
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| 8. |
- Deb, Suryyani, et al.
(författare)
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Self-Reporting Theranostic : Nano Tool for Arterial Thrombosis
- 2023
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Ingår i: Bioengineering. - : MDPI. - 2306-5354. ; 10:9
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Tidskriftsartikel (refereegranskat)abstract
- Arterial thrombosis (AT) originates through platelet-mediated thrombus formation in the blood vessel and can lead to heart attack, stroke, and peripheral vascular diseases. Restricting the thrombus growth and its simultaneous monitoring by visualisation is an unmet clinical need for a better AT prognosis. As a proof-of-concept, we have engineered a nanoparticle-based theranostic (combined therapy and monitoring) platform that has the potential to monitor and restrain the growth of a thrombus concurrently. The theranostic nanotool is fabricated using biocompatible super-paramagnetic iron oxide nanoparticles (SPIONs) as a core module tethered with the anti-platelet agent Abciximab (ReoPro) on its surface. Our in vitro feasibility results indicate that ReoPro-conjugated SPIONS (Tx@ReoPro) can effectively prevent thrombus growth by inhibiting fibrinogen receptors (GPIIbIIIa) on the platelet surface, and simultaneously, it can also be visible through non-invasive magnetic resonance imaging (MRI) for potential reporting of the real-time thrombus status.
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| 9. |
- Deb, Suryyani, et al.
(författare)
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Varying effects of tyrosine kinase inhibitors on platelet function : A need for individualized CML treatment to minimize the risk for hemostatic and thrombotic complications?
- 2020
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Ingår i: Cancer Medicine. - : John Wiley & Sons. - 2045-7634. ; 9:1, s. 313-323
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Tidskriftsartikel (refereegranskat)abstract
- Since their introduction, tyrosine kinase inhibitors (TKIs, eg, imatinib, nilotinib, dasatinib, bosutinib, ponatinib) have revolutionized the treatment of chronic myeloid leukemia (CML). However, long-term treatment with TKIs is associated with serious adverse events including both bleeding and thromboembolism. Experimental studies have shown that TKIs can cause platelet dysfunction. Herein, we present the first side-by-side investigation comparing the effects of currently used TKIs on platelet function and thrombin generation when used in clinically relevant concentrations. A flow cytometry multiparameter protocol was used to study a range of significant platelet activation events (fibrinogen receptor activation, alpha granule, and lysosomal exocytosis, procoagulant membrane exposure, and mitochondrial permeability changes). In addition, thrombin generation was measured in the presence of TKIs to assess the effects on global hemostasis. Results show that dasatinib generally inhibited platelet function, while bosutinib, nilotinib, and ponatinib showed less consistent effects. In addition to these general trends for each TKI, we observed a large degree of interindividual variability in the effects of the different TKIs. Interindividual variation was also observed when blood from CML patients was studied ex vivo with whole blood platelet aggregometry, free oscillation rheometry (FOR), and flow cytometry. Based on the donor responses in the side-by-side TKI study, a TKI sensitivity map was developed. We propose that such a sensitivity map could potentially become a valuable tool to help in decision-making regarding the choice of suitable TKIs for a CML patient with a history of bleeding or atherothrombotic disease.
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| 10. |
- Frelinger, Andrew L., 3rd, et al.
(författare)
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Consensus recommendations on flow cytometry for the assessment of inherited and acquired disorders of platelet number and function : Communication from the ISTH SSC Subcommittee on Platelet Physiology
- 2021
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Ingår i: Journal of Thrombosis and Haemostasis. - : John Wiley & Sons. - 1538-7933 .- 1538-7836. ; 19:12, s. 3193-3202
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Tidskriftsartikel (refereegranskat)abstract
- Flow cytometry is increasingly used in the study of platelets in inherited and acquired disorders of platelet number and function. However, wide variation exists in specific reagents, methods, and equipment used, making interpretation and comparison of results difficult. The goal of the present study was to provide expert consensus guidance on the use of flow cytometry for the evaluation of platelet disorders. A modified RAND/UCLA survey method was used to obtain a consensus among 11 experts from 10 countries across four continents, on the appropriateness of statements relating to clinical utility, pre-analytical variables, instrument and reagent standardization, methods, reporting, and quality control for platelet flow cytometry. Feedback from the initial survey revealed that uncertainty was sometimes due to lack of expertise with a particular test condition rather than unavailable or ambiguous data. To address this, the RAND method was modified to allow experts to self-identify statements for which they could not provide expert input. There was uniform agreement among experts in the areas of instrument and reagent standardization, methods, reporting, and quality control and this agreement is used to suggest best practices in these areas. However, 25.9% and 50% of statements related to pre-analytical variables and clinical utility, respectively, were rated as uncertain. Thus, while citrate is the preferred anticoagulant for many flow cytometric platelet tests, expert opinions differed on the acceptability of other anticoagulants, particularly heparin. Lack of expert consensus on the clinical utility of many flow cytometric platelet tests indicates the need for rigorous multicenter clinical outcome studies.
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