Platelet activation and residual activation potential during storage of hyperconcentrated platelet products in two different platelet additive solutions.

BACKGROUND: To improve platelet (PLT) quality, hyperconcentrated PLT concentrates (hcPCs) were compared to standard PLT concentrates (stdPCs) in two different PLT additive solutions, T-Sol and PAS-27a. PAS-27a differs from T-Sol by containing glucose, phosphate, potassium, magnesium, and bicarbonate. STUDY DESIGN AND METHODS: PLTs were harvested by apheresis twice from 14 donors; each unit was divided into two. Four units from each donor were produced: hcPCs, 2000 x 10(9) per L in T-Sol or PAS-27a; and stdPCs, 1400 x 10(9) per L in 65 percent T-Sol or PAS-27a and 35 percent acid citrate dextrose-plasma. On Days 1 through 4, swirling was scored and PLT count, mean PLT volume, pH, blood gas, glucose, and lactate were measured. Expression of CD42a, CD62P, CD63, and PAC-1 was analyzed by flow cytometry on resting PLTs and PLTs stimulated with thrombin receptor agonist peptide (TRAP).
RESULTS: Glucose consumption and lactate production were significantly higher in hcPCs stored in PAS-27a than in T-Sol. Both stdPC and hcPC PLTs in T-Sol expressed CD62P and PAC-1 significantly higher than in PAS-27a. Over time the T-Sol hcPCs revealed highest expression of CD62P and CD63. A significantly higher capacity for up regulation of CD62P, CD63, and PAC-1 upon TRAP stimulation was found for stdPCs and hcPCs in PAS-27a compared to PLTs in T-Sol. TRAP-stimulated PLTs in stdPCs and hcPCs suspended in PAS-27a showed significantly higher potential for down regulation of CD42a than the T-Sol concentrates.
CONCLUSIONS: PLTs appear better preserved in vitro in PAS-27a than in T-Sol, and this suggests that storage of hcPCs in PAS-27a could be extended beyond 24 hours.