Trehalose inhibited the phagocytosis of refrigerated platelets in vitro via preventing apoptosis

Abstract

BACKGROUND: The sole reason that platelets (PLTs) are currently stored at room temperature is that refrigeration of PLTs results in their rapid clearance after transfusion. Recent data have suggested that trehalose was an effective cryoprotective reagent for human PLTs. This study evaluated the effect of trehalose on the phagocytosis of refrigerated PLTs. STUDY DESIGN AND METHODS: Phagocytosis of PLTs was evaluated with THP-1 cells. Phosphatidylserine exposure and caspase-3 activity in PLTs were measured with flow cytometry. PLT mitochondrial transmembrane potentials were studied by staining PLTs with JC-1. Expression of Bcl-XL and Bax was determined by Western blot. PLT aggregation was studied in vitro with a PLT aggregation profiler. RESULTS: It was demonstrated that trehalose significantly inhibited the phagocytosis of refrigerated PLTs by showing that the phagocytotic ratio of PLTs refrigerated with trehalose for 9 days was generally comparable with that of PLTs stored at room temperature for 5 days, which was significantly lower than that of PLTs refrigerated without trehalose. Further studies revealed that trehalose could prevent the apoptosis of refrigerated PLTs, which was determined by the phosphatidylserine exposure, caspase-3 activities, mitochondrial transmembrane potentials, and expression of Bcl-XL and Bax. Finally, it was shown that PLTs refrigerated with trehalose for 9 days also maintained their activity to aggregate when exposed to agonists in a standard aggregometry assay. CONCLUSION: Our results suggest that trehalose could inhibit the phagocytosis of refrigerated PLTs in vitro through preventing apoptosis, implying that trehalose is a promising candidate to optimize the refrigeration of human PLTs.