Abstract Number: PB1665
Meeting: ISTH 2020 Congress
Background: Platelet lifespan within the circulation of healthy humans is about 10 days but is shortened in a number of disease states. Despite reports indicating associations between increased percentages of newly formed platelets and risk of thrombosis, evidence of age-related differences in platelet composition is lacking.
Aims: To determine changes in composition of platelets across their lifespan using proteomic analysis coupled with immunofluorescence.
Methods: Platelets were stained with thiazole orange (TO) and separated into two subpopulations by cell sorting based on TO staining intensity (Aria IIIu). The top 10% of TO-positive platelets were categorised as ‘young’ and the bottom 30% as ‘old’. The platelet proteome profile was determined by label-free quantitative mass spectrometry (nanoHPLC-Q Exactive MS/MS) and analysed by MaxQuant and Perseus software. Confocal microscopy was used to assess changes in the cytoskeleton of resting and adherent platelet subpopulations.
Results: Proteomics revealed a significant alteration in 78 proteins between young and old platelets. Young platelets had a relatively higher content of a number of cytoskeletal-associated proteins including emerin, gelsolin and twinfilin-2. Microscopy confirmed that young platelets had a more abundant and complex cytoskeleton compared to old platelets, with a significant reduction in the fluorescence intensity of α-tubulin (2435±354AU vs. 1034±79AU) and f-actin (2166±110AU vs. 1364±139AU; p< 0.05, n=4), but without any differences in platelet cross-sectional area. When spread on fibrinogen, young platelets readily formed lamellipodia with a larger spread area than old platelets (24.2±2.8µm2 vs. 7.9±0.5µm2; p< 0.05, n=4), with a higher abundance of actin nodules (63±1% vs. 24±1% of spread platelets; p< 0.05, n=4).
Conclusions: Platelet ageing is associated with a decline in cytoskeletal content and a subsequent reduction in cytoskeletal reorganisation. These reductions may contribute to a decrease in haemostatic function and an increase in clearance of platelets as they age.
To cite this abstract in AMA style:Allan HE, Hayman MA, Marcone S, Chan MV, Crescente M, Menke L, Armstrong PC, Warner TD. Platelet Ageing Is Associated with Cytoskeletal Degradation and a Reduction in Cytoskeletal Dynamics [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/platelet-ageing-is-associated-with-cytoskeletal-degradation-and-a-reduction-in-cytoskeletal-dynamics/. Accessed October 1, 2023.
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