Enhancing Platelet Preservation through Freeze-Drying and Sterilization: An Approach for the Improvement of Hemostatic Treatment and Platelet Concentrate Supply

Background: The limited shelf life of platelets has led to an increasing demand for longer-lasting products. This study aimed to develop a lyophilization protocol to preserve platelets by using trehalose, a desiccation-resistant sugar, and comparing its effectiveness to sucrose, a standard sugar for protein lyophilization. Materials and Methods: In this interventional study, the platelets were loaded with trehalose (30, 60, or 100 mM) and 2% sucrose and then freeze-dried. Evaluations were performed of platelet count, aggregation responses to the agonists thrombin (1 U/ml), collagen (2 µg/ml), adenosine diphosphate (ADP) (20 µM), and the expression of the activation surface marker CD62P. Gamma radiation (30 and 40 kGy) was evaluated for pathogen inactivation in lyophilized products through measuring the reduction factors for viral titers (Herpes Simplex Virus-1 (HSV-1) and Poliovirus) and bacterial titers (S. epidermidis and E. coli). The analyses were conducted using SPSS v23.0.1 and GraphPad Prism v10. Results: The platelet count in the 60 mM trehalose group showed no significant change after lyophilization (mean difference: 78.33; P = 0.31). The flow-cytometry analysis revealed a significant increase of CD62P in the control and sucrose-treated groups (P < 0.01 for all the groups), while trehalose significantly preserved the platelet function. This was demonstrated by lower CD62P (7.88%, P = 0.000) and higher thrombin-induced aggregation (53.46%, P = 0.01) and ADP-induced aggregation (29.8%, P = 0.001) compared to the other groups. Gamma radiation achieved a 5.2-log reduction at 30 kGy and a 6.2-log reduction at 40 kGy for Poliovirus, along with a consistent 7-log reduction for HSV-1 at both. Additionally, titers of S. epidermidis and E. coli were reduced by more than 7 logs, rendering them undetectable. Conclusion: Lyophilized platelets stabilized with trehalose and sterilized with gamma radiation represent a promising approach for dealing with the current limitations in platelet storage and availability