| 1. |
|
|
| 2. |
- Boknäs, Niklas, 1979-, et al.
(författare)
-
Platelet function testing at low platelet counts : When can you trust your analysis?
- 2019
-
Ingår i: Research and Practice in Thrombosis and Haemostasis. - : Wiley-Blackwell. - 2475-0379. ; 3:2, s. 285-290
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Although flow cytometry is often brought forward as a preferable method in the setting of thrombocytopenia, the relative effects of low sample counts on results from flow cytometry-based platelet function testing (FC-PFT) in comparison with light transmission aggregometry (LTA) and multiple electrode aggregometry (MEA) has not been reported.Objectives: To compare the effects of different sample platelet counts (10, 50, 100, and 200x10(9)L(-1)) on platelet activation measured with FC-PFT, LTA, and MEA using the same anticoagulant and agonist concentrations as for the commercial MEA test.Methods: Platelets were stimulated with two commonly used platelet agonists (ADP [6.5 mu molL(-1)] and PAR1-AP [TRAP, 32 mu molL(-1)]). The specified sample platelet counts were obtained by combining platelet-rich and platelet poor hirudinized plasma in different proportions with or without red blood cells.Results: For FC, P-selectin exposure and PAC-1 binding was reduced at 10x10(9)L(-1) after stimulation with PAR1-AP (by approximately 20% and 50%, respectively), but remained relatively unchanged when ADP was used as agonist (n=9). The platelet count-dependent effects observed with PAR1-AP were eliminated when samples were pre-incubated with apyrase, implying that reduced purinergic signaling was the main underlying factor (n=5). Both aggregometry-based PFTs showed a 50% reduction at 50x10(9)L(-1) and more than 80% reduction at 10x10(9)L(-1), irrespective of agonist used (n=7).Conclusions: Although FC-PFT is generally preferable to aggregometry-based PFTs in situations with low sample platelet counts, a careful optimization of experimental parameters is still required in order to eliminate platelet count-related effects.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Tynngård, Nahreen, et al.
(författare)
-
Platelet adhesion changes during storage studied with a novel method using flow cytometry and protein-coated beads
- 2015
-
Ingår i: Platelets. - : Taylor & Francis. - 0953-7104 .- 1369-1635. ; 26:2, s. 177-185
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to set up and evaluate a novel method for studies of platelet adhesion and activation in blood and platelet suspensions such as platelet concentrate (PC) samples using protein-coated polystyrene beads and flow cytometry. To demonstrate its usefulness, we studied PCs during storage. PCs were prepared by aphaeresis technique (n = 7). Metabolic variables and platelet function was measured on day 1, 5, 7 and 12 of storage. Spontaneous and TRAP-6-induced adhesion to fibrinogen-and collagen-coated beads was analyzed by flow cytometry. P-selectin and phosphatidyl serine (PS) expression was assessed on platelets bound to beads as well as on non-adherent platelets. Platelet adhesion to fibrinogen beads had increased by day 12 and adhesion to collagen beads at day 7 of storage (p<0.05). TRAP-6 stimulation significantly increased the platelet adhesion to fibrinogen beads (p<0.05) as well as the P-selectin and PS exposure on platelets bound to beads (p<0.01) during the first 7 days of storage, but by day 12, significant changes were no longer induced by TRAP-6 stimulation. We demonstrate that our adhesion assay using protein-coated polystyrene beads can be used to assess the adhesion properties of platelets during storage without the addition of red blood cells. Therefore it may offer a useful tool for future studies of platelet adhesive capacity in transfusion medicine and other settings.
|
|
