Biochemical and structural changes in RBCs stored with different plasticizers: the role of hexanol

BACKGROUND: PVC containers are plasticized with di(2-ethyl)hexylphthalate (DEHP) or a related phthalate. The toxicity of DEHP has been questioned. It has been proposed to use butyryltrihexylcitrate (BTHC) as the plasticizer. The purpose of this study was to determine if hexanol, a component of BTHC, plays a role in the preservation of RBCs stored in BTHC-plasticized PVC bags. STUDY DESIGN AND METHODS: WBC-reduced RBCs of ABO- and D-matched blood groups were prepared in 1-L polyolefin (PO) bags (PL732). Six 60-g aliquots were transferred to transfer packs made of PL146 (DEHP-plasticized) and PL2209 (BTHC-plasticized) and four PO (PL732) packs. To the PL146 and PL2209 packs, 30 mL of AS-1 was added. To three of the PO packs, 30 mL of AS-1 with sufficient DEHP, BTHC, or hexanol to achieve a final concentration of 3 mM was added, and to the final PO pack, 30 mL of AS-1 only was added (control). The units were stored for 6 weeks at 1 to 6 degrees C. RBC ATP, hemolysis, morphology, membrane lipids, deformability, and fluidity were measured. RESULTS: ATP levels were not significantly different in any of the systems after 6 weeks. Compared to the PO bags, hemolysis was lowest in the PL146 containers and was also significantly lower (p < 0.006) in the PO bags with added DEHP, BTHC, or hexanol. The accumulation of vesicles was significantly less in the units stored in the PL146 and PL2209 than in the PO plastic with or without added plasticizers or hexanol (p < or = 0.004). There was no significant difference in the formation of vesicles in any of the PO units (p > 0.05). There was no demonstrable change in the membrane fluidity of the RBCs during storage in any of the systems. The decrease in deformability was the same, and the losses of cholesterol and phospholipid during storage were similar in all the studies. CONCLUSIONS: The hexanol component of the BHTC plasticizer in a concentration of 144.6 microg per mL concentration suppresses hemolysis and vesiculation of RBCs during storage. The hexanol and DEHP that are slowly leached during storage have a greater effect in suppressing hemolysis and vesicle formation than when added extraneously to AS-1 in PO containers.