Reduction of ristocetin-induced platelet aggregation (RIPA) during storage despite plasma renewal: evidence for hemostatic importance of GPIbα shedding

ABSTRACT

Background

Platelet storage is complicated by deleterious changes, among which reduction of ristocetin-induced platelet aggregation (RIPA) has a poorly understood mechanism. The study elucidates the mechanistic roles of all the possible players in this process.

Research design and methods

PRP-platelet concentrates were subjected to RIPA, collagen-induced platelet aggregation (CIPA), and flowcytometric analysis of GPIbα and PAC-1 binding from days 0 to 5 of storage. Platelet-poor plasma was subjected to colorimetric assays for glucose/LDH evaluation and automatic analyzer to examine VWF antigen and activity.

Results

From day three of platelet storage, reducing CIPA but not RIPA was correlated with the reduction of both metabolic state and integrin activity. RIPA reduction was directly related to the decreased levels of total-content/expression of GPIbα, and inversely related to its shedding levels during storage. Re-suspension of 5-day stored platelet in fresh plasma compensated CIPA, but not RIPA. VWF concentration and its activity did not change during storage while they had no correlation with RIPA.

Conclusions

This study identified the irreversible loss of platelet GPIbα, but not VWF status, as the primary cause of the storage-dependent decrease of RIPA. Unlike CIPA, this observation was not compensated by plasma refreshment, suggesting that some evidence of PSL may not be recovered after transfusion.

KEYWORDS:

• Aggregation
• ectodomain shedding
• GPIbα
• integrin alpha-iib beta-3
• ristocetin
• platelet storage lesion
• thrombosis
• transfusion

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

M Ghasemzadeh provided the conceptual input, supervised and designed the study, performed the experiments, analyzed the data, and wrote the paper. E Hosseini provided conceptual input, co-supervised the study, performed the experiments, and co-wrote the paper. E Taherabadi provided conceptual input, performed the experiments, and co-wrote the paper. A Rajabi performed the aggregation assays.

Ethical approval

The research was conducted in accordance with the principles embodied in the Declaration of Helsinki and received approval from a regional Ethics committee at the High Institute for Research and Education in Transfusion Medicine, Iran (Ethic committee approval number: IR.TMI.REC.1400.022 and IR.TMI.REC.1401.011).

Acknowledgments

Parts of this paper were presented as a dissertation for Master student E Taherabadi. The authors wish to thank R Ranjbar from Tehran Blood Transfusion Center, as well as M Ahmadinejad, Head of the Coagulation Laboratory of Iran Blood Transfusion Organization.

Data availability statement

The corresponding author can make available some datasets upon reasonable request.

Additional information

Funding

This work is a part of M Ghasemzadeh’s projects, which were supported by their personally allocated grants [Tracking Codes: 1400-1234 & 1401-1233] and approved by the High Institute for Research and Education in Transfusion Medicine.