Lyophilization of Human Platelet and Study of its Aggregability

Human platelet concentrates are usually stored in blood banks for 5 days, after expiration date they are discarded. Human lyophilized platelet is one of the approaches to preserve the platelets for long time storage. In our study trehalose was used as a stabilizer to protect the platelets during freezing and drying conditions.Platelet rich plasma was prepared as a source of platelet concentrate.Washed platelets were incubated in the presence of trehalose (40 mM /l) trehalose for 4 h at 37°C. After lyophilization. prehydration and rehydration stages, the response of lyophilized human platelets to the agonists such as ADP, ristositin and arachidonic acid were measured by an aggregometer instrument. Aggregation of platelets with ADP, ristositin and arachidonic acid showed 75.5%, 55.9% and 17.3% activity respectively. Clot formation at 37°C was clearly observed within 5 min after addition of these agonists to rehydrated lyophilized platelets.Our study showed that this method of preserving platelets with internal trehalose loading is possible in the dried state for storage at room temperature but for its quality improvement further investigation is required. Keywords: Lyophilization, trehalose, platelet aggregation.