Platelet Hemostasis Reactions at Different Temperatures Correlate with Intracellular Calcium Concentration

Abstract

Hypo- and hyperthermia affect both primary and secondary hemostasis; however, there are controversial data concerning platelet activation and the underlying mechanisms under hypo- and hyperthermia. The discrepancies in the data could be partly explained by different approaches to hemostatic reactions analysis. We applied a new LaSca-TMF laser particle analyzer for a simultaneous fluorescence and laser scattering analysis of platelet responses at different temperatures. Human platelets were activated by ADP in a wide range of temperatures, and platelet transformations (e.g., a shape change reaction, aggregation and clot formation) and the intracellular calcium concentration ([Ca2+]i) were analyzed by LaSca-TMF and confocal microscopy. The platelet shape change reaction gradually increased with a rising temperature. The platelet aggregation strongly decreased at low ADP concentrations with the augmentation of the temperature and was independent of the temperature at high ADP concentrations. In contrast, the clotting time decreased with a temperature increase. Similar to the aggregation response, a rise in [Ca2+]i triggered by low ADP concentrations was higher under hypothermic conditions and the differences were independent of the temperature at high ADP concentrations. We showed that the key reactions of cellular hemostasis are differentially regulated by temperature and demonstrated for the first time that an accelerated aggregation under hypothermic conditions directly correlated with an increased level in [Ca2+]i in platelets.

Platelets in Alcohol-Associated Liver Disease: Interaction With Neutrophils

“… 11 This activation is essential for the hemostatic effects of platelets, as well as their diverse physiological functions. 12 , 13 The hemostatic effects of platelets are crucial for preventing excessive bleeding. Beyond hemostasis, platelets have diverse physiological functions.…”

Bioactive Hydrogels with Pro‐coagulation Effect for Hemostasis†

“…[ 180‐181 ] Platelets attached to the site of injury are further activated, releasing ADP, TXA2, and VWF (VWF), among other factors, to facilitate platelet activation, adhesion, recruitment, and aggregation, ultimately forming a platelet plug at the bleeding site and achieving primary hemostasis. [ 182‐184 ] Various coagulation factors, including factor Va, factor XIa, factor XIIIa, and fibrinogen, can bind to the surface sites of platelets, thereby accelerating the clotting process. [ 185‐187 ] Platelets also secrete the anionic polymer PolyP and release platelet factor 4 (PF4) from α particles, which promote fibrin formation and participate in secondary hemostasis.…”

Platelet Functional Testing Via High‐Throughput Microtiter Plate‐Based Assays

“…Standardization has been further hampered by conflicting studies on key variables that have been discussed in depth by others (Cattaneo et al, 2009(Cattaneo et al, , 2013Cazenave et al, 2004;Hechler, Dupuis, Mangin, & Gachet, 2019;Jarvis, 2004). Briefly, the following parameters are often contested including: (1) choice of the anticoagulant, (2) blood collection method (vacutainers, syringe, drip), (3) storage temperature (ambient or 37°C; Mindukshev et al, 2022), (4) components of Tyrode's buffer (BSA, divalent cations, apyrase), and (5) platelet concentration (Tiffany & Henry, 1983).…”

“…The lack of standardization in laboratory practices can in part be attributed to the inability to decipher what is an artifactual platelet response and what is true platelet reactivity. For example, one study reported that platelets stored at ambient temperature have an increase in reactivity compared with platelets stored at 37°C (Mindukshev et al., 2022), whereas another study attributed the increased reactivity of platelets stored at ambient temperature to being an artifact caused by preactivation during storage (Maurer‐Spurej et al., 2001). Standardization has been further hampered by conflicting studies on key variables that have been discussed in depth by others (Cattaneo et al., 2009, 2013; Cazenave et al., 2004; Hechler, Dupuis, Mangin, & Gachet, 2019; Jarvis, 2004).…”