Cryopreservation of human platelets with propane-1,2-diol

Area of Science:

• Biotechnology
• Hematology
• Cryobiology

Background:

• Human platelets are crucial for hemostasis but have limited storage viability.
• Propane-1,2-diol (propylene glycol, PG) has been successfully introduced/removed from platelets.
• Previous studies established methods for PG manipulation in platelets up to 2 M.

Purpose of the Study:

• To evaluate the efficacy of cryopreserving human platelets using various concentrations of propylene glycol (PG).
• To assess platelet survival post-cryopreservation using hypotonic stress response and ADP-induced aggregation assays.
• To determine the relationship between PG concentration, cooling rates, and platelet damage during freezing.

Main Methods:

• Platelets were cryopreserved with PG concentrations ranging from 0.5 M to 2.5 M.
• Cooling rates varied between 0.4 and 100 degrees C/min.
• Platelet function was assessed via hypotonic stress response and ADP-induced aggregation.

Main Results:

• Optimal cryopreservation yielded only 17% hypotonic stress response and 6% ADP-induced aggregation.
• These results were achieved with 0.5 M PG, a cooling rate of 14 degrees C/min, and rapid warming.
• Higher PG concentrations (>0.5 M) did not improve, and often worsened, platelet survival.

Conclusions:

• The cryoprotective effect of PG is counteracted by its increasing toxicity at higher concentrations.
• Ice formation during freezing concentrates PG, leading to a steep increase in toxicity.
• Platelet cryopreservation using PG is limited by the solute's concentration-dependent toxicity exacerbated by freezing conditions.