Endogenous glutathione and platelet function in platelet concentrates stored in plasma or platelet additive solution

Platelet function was studied in platelet concentrates by assay of the thro mbin-induced release of endogenous serotonin and presence of the swirling p henomenon in relation to endogenous glutathione (GSH) and cysteine. In platelets stored in plasma, addition of cysteamine resulted in only a mo derate fall in GSH after 5 days of storage, from an average of 14.91 to 11. 46 nmol per 10(9) platelets. Exogenously added GSH had no effect, and addit ion of buthionine sulfoximine (BSO) resulted in almost complete depletion o f GSH, to an average of 0.65 nmol per 109 platelets. Addition of cysteamine or GSH resulted in increased endogenous cysteine whereas BSO had no effect . In platelets stored in a platelet additive solution (T-sol(R)), complete de pletion of GSH was found in the presence of cysteamine, GSH and BSO. Endogenous serotonin was unchanged during storage both in plasma and in add itive solution (2.8 nmol per 10.9 platelets). Despite almost total depletio n of endogenous GSH, the thrombin-induced release of serotonin after 5 days ' storage was significantly affected only in the presence of BSO in platele ts stored in additive solution (mean values 72.3% vs. 63.3% of endogeneous serotonin, P < 0.05). Similarly, addition of cysteamine or GSH had no significant effect on swirl ing but BSO reduced the swirling score after 5 days' storage in platelet ad ditive solution compared with plasma. After 10 days' storage, there was a s ignificant reduction in swirling in the concentrates where BSO was added (P < 0.05).