Periods without agitation diminish platelet mitochondrial function during storage

BACKGROUND: Prolonged periods without agitation produce platelet (PLT) storage lesions that result in reduced in vitro assay parameters and an increase of apoptotic markers during storage. The aim of this study was to evaluate the influence of periods without agitation on PLT mitochondrial function, blood gases, and activation. STUDY DESIGN AND METHODS: Apheresis PLT units (n = 12) were collected using a cell separator and each was equally divided among five storage bags (50 mL of PLT suspension in 300-mL nominal volume containers). Four bags were held without agitation for 24, 48, 72, and 96 hours in a standard shipping box at room temperature and the fifth bag was continuously agitated. PLTs were assayed for standard in vitro PLT assays as well as for mitochondrial membrane potential (MMP), accumulation of reactive oxygen species, Annexin V binding, mitochondrial mass, and activity of mitochondrial reduction power (MRP) immediately after removal of units from the shipping container on Days 1, 2, 3, 4, and 7. RESULTS: Increasing periods without agitation resulted in increased superoxide anion generation and PLT activation as well as reduced PLT MMP and MRP. Increasing periods without agitation resulted in increasing Annexin V binding. PLTs that had undergone periods without agitation showed increased oxygen and carbon dioxide levels immediately after storage without agitation. The superoxide anion generation was highly correlated with the loss of MMP, increasing Annexin V binding, and pH decline. CONCLUSIONS: PLTs, if stored without agitation, produce a lesion that leads PLTs to apoptosis. The severity of the lesion depends on the length of the period without agitation. Prolonged periods without agitation induce formation of superoxides and depolarization of MMP along with a presentation of apoptotic markers.