Now showing 1 - 4 of 4
  • Publication
    Thrombin generation correlates with disease duration in multiple sclerosis (MS): Novel insights into the MS-associated prothrombotic state
    Background: Thrombin is well recognised for its role in the coagulation cascade but it also plays a role in inflammation, with enhanced thrombin generation observed in several inflammatory disorders. Although patients with multiple sclerosis (MS) have a higher incidence of thrombotic disease, thrombin generation has not been studied to date. Objectives: The aim of this study was to characterise calibrated automated thrombography parameters in patients with relapsing–remitting MS (RRMS) and primary progressive MS (PPMS) in comparison to healthy controls (HCs). Methods: Calibrated automated thrombography was performed on platelet poor plasma from 15 patients with RRMS, 15 with PPMS and 19 HCs. Results: We found that patients with RRMS generate thrombin at a significantly faster rate than the less inflammatory subtype, PPMS or HCs. In addition, the speed of thrombin generation was significantly correlated with time from clinical diagnosis in both subtypes. However, in RRMS the rate of thrombin generation was increased with increased time from clinical diagnosis, while in PPMS the rate of thrombin generation decreased with increased time from clinical diagnosis. Conclusions: These data likely reflect the differential active proinflammatory states in each MS subtype and provide novel mechanistic insights into the clinically relevant prothrombotic state observed in these patients.
      294Scopus© Citations 11
  • Publication
    Platelet extracellular vesicles induce a pro-inflammatory smooth muscle cell phenotype
    Extracellular vesicles (EVs) are mediators of cell communication during health and disease, and abundantly released by platelets upon activation or during ageing. Platelet EVs exert modulatory effects on immune and vascular cells. Platelet EVs may modulate the function of vascular smooth muscle cells (SMC). Platelet EVs were isolated from platelet-rich plasma and incubated with SMC in order to assess binding, proliferation, migration and pro-inflammatory phenotype of the cells. Platelet EVs firmly bound to resting SMC through the platelet integrin αIIbβ3, while binding also occurred in a CX3CL1–CX3CR1-dependent manner after cytokine stimulation. Platelet EVs increased SMC migration comparable to platelet derived growth factor or platelet factor 4 and induced SMC proliferation, which relied on CD40- and P-selectin interactions. Flow-resistant monocyte adhesion to platelet EV-treated SMC was increased compared with resting SMC. Again, this adhesion depended on integrin αIIbβ3 and P-selectin, and to a lesser extent on CD40 and CX3CR1. Treatment of SMC with platelet EVs induced interleukin 6 secretion. Finally, platelet EVs induced a synthetic SMC morphology and decreased calponin expression. Collectively, these data indicate that platelet EVs exert a strong immunomodulatory activity on SMC. In particular, platelet EVs induce a switch towards a pro-inflammatory phenotype, stimulating vascular remodelling.
    Scopus© Citations 83  383
  • Publication
    A Protocol for Improved Precision and Increased Confidence in Nanoparticle Tracking Analysis Concentration Measurements between 50 and 120 nm in Biological Fluids
    Nanoparticle tracking analysis (NTA) can be used to quantitate extracellular vesicles (EVs) in biological samples and is widely considered a useful diagnostic tool to detect disease. However, accurately profiling EVs can be challenging due to their small size and heterogeneity. Here, we aimed to provide a protocol to facilitate high-precision particle quantitation by NTA in plasma, the supernatant of activated purified platelets [the platelet releasate (PR)] and in serum, to increase confidence in NTA particle enumeration. The overall variance and the precision of NTA measurements were quantified by root mean square error and relative standard error. Using a bootstrapping approach, we found that increasing video replicates from 5 s × 60 s to 25 s × 60 s captures led to a reduction in overall variance and a reproducible increase in the precision of NTA particle-concentration quantitation for all three biofluids. We then validated our approach in an extended cohort of 32 healthy donors. Our results indicate that for vesicles sized between 50 and 120 nm, the precision of routine NTA measurements in serum, plasma, and PR can be significantly improved by increasing the number of video replicates captured. Our protocol provides a common platform to statistical compare particle size distribution profiles in the exosomal-vesicle size range across a variety of biofluids and in both healthy donor and patient groups.
      380Scopus© Citations 37
  • Publication
    Examining gender effects in different types of undergraduate science assessment
    The optimum assessment structure measures student knowledge accurately and without bias. In this study, the performance of the first-year undergraduate science students from the University College Dublin was evaluated to test the gender equality of the assessment structure in place. Results of male and female students taking three life science modules were analysed, for two academic years, with assessment structure based on a combination of three types of evaluation: continuous assessment and multiple choice questions (MCQ) exam scored with/without negative marking. We found no significant gender effect associated with performance in continuous assessment, or MCQ exams scored without negative marking. However, a significant bias against females was consistently observed for the same cohort of students in the MCQ exams with negative marking of 0.25 points. This bias was at least partially linked to a gender difference in willingness to guess and preliminary data suggest that it disappears after removal of negative marking from the MCQ exams. Our results support the view of a diverse assessment structure being fairer to the students. Moreover, caution is advised while using negative marking, and regular reviews of assessment strategy should be implemented by higher education institutions to ensure gender-bias free evaluation of students’ performance.
    Scopus© Citations 5  244