Generation of Platelet Microparticles after Cryopreservation of Apheresis Platelet Concentrates Contributes to Hemostatic Activity.
OBJECTIVE
In the last decade, substantial evidence has accumulated about the use of cryopreserved platelet concentrates, especially in trauma. However, little reference has been made in these studies to the morphological and functional changes of platelets. Recently platelets have been shown to be activated by cryopreservation processes and to undergo procoagulant membrane changes resulting in the generation of platelet-derived microparticles (PMPs), platelet degranulation, and release of platelet-derived growth factors (PDGFs). We assessed the viabilities and the PMP and PDGF levels of cryopreserved platelets, and their relation with thrombin generation.


METHODS
Apheresis platelet concentrates (APCs) from 20 donors were stored for 1 day and cryopreserved with 6% dimethyl sulfoxide. Cryopreserved APCs were kept at -80 °C for 1 day. Thawed APCs (100 mL) were diluted with 20 mL of autologous plasma and specimens were analyzed for viabilities and PMPs by flow cytometry, for thrombin generation by calibrated automated thrombogram, and for PDGFs by enzyme-linked immunosorbent assay testing.


RESULTS
The mean PMP and PDGF levels in freeze-thawed APCs were significantly higher (2763±399.4/µL vs. 319.9±80.5/µL, p<0.001 and 550.9±73.6 pg/mL vs. 96.5±49 pg/mL, p<0.001, respectively), but the viability rates were significantly lower (68.2±13.7% vs. 94±7.5%, p<.001) than those of fresh APCs. The mean endogenous thrombin potential (ETP) of freeze-thawed APCs was significantly higher than that of the fresh APCs (3406.1±430.4 nM.min vs. 2757.6±485.7 nM.min, p<0.001). Moreover, there was a significant positive poor correlation between ETP levels and PMP levels (r=0.192, p=0.014).


CONCLUSIONS
Our results showed that, after cryopreservation, while levels of PMPs were increasing, significantly higher and earlier thrombin formation was occurring in the samples analyzed despite the significant decrease in viability. Considering the damage caused by the freezing process and the scarcity of evidence for their in vivo superiority, frozen platelets should be considered for use in austere environments, reserving fresh platelets for prophylactic use in blood banks.
İbrahim
İ
Eker
University of Health Sciences Gülhane Faculty of Medicine, Blood Training Center and Blood Bank, Ankara, Turkey Phone : +90 312 304 4902 E-mail: drsoneryilmaz@gmail.com.
Soner
S
Yılmaz
Rıza Aytaç
RA
Çetinkaya
Aysel
A
Pekel
Aytekin
A
Ünlü
Orhan
O
Gürsel
Sebahattin
S
Yılmaz
Ferit
F
Avcu
Uğur
U
Muşabak
Ahmet
A
Pekoğlu
Zerrin
Z
Ertaş
Cengizhan
C
Açıkel
Nazif
N
Zeybek
Ahmet Emin
AE
Kürekçi
İsmail Yaşar
İY
Avcı
D001781:Blood Component Removal; D001782:Blood Donors; D001792:Blood Platelets / Q000166:cytology* / Q000378:metabolism; D002470:Cell Survival; D055252:Cell-Derived Microparticles / Q000378:metabolism*; D015925:Cryopreservation; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005615:Freezing; D006801:Humans; D010982:Platelet-Derived Growth Factor / Q000032:analysis; D013918:Thrombin Time
D010982:Platelet-Derived Growth Factor; D004121:Dimethyl Sulfoxide