Improving Oxygen Binding of Desiccated Human Red Blood Cells

Desiccating human red blood cells (RBCs) to increase their storage life has been the subject of intense research for a number of years. However, drying RBCs invariably compromises their integrity and has detrimental effects on hemoglobin function due to autoxidation. We have previously demonstrated an RBC desiccation and rehydration process that preserves RBC antigenic epitopes better than frozen RBCs. This study expands on those observations by examining what effects this desiccation process has on RBC hemoglobin function with respect to oxygen binding properties. In this paper, we examined RBCs from normal donors which were desiccated to 25% moisture content and stored dry for 2 weeks at room temperature prior to rehydration with plasma followed by structural and functional studies. Our data showed that approximately 98% of the RBCs were intact upon rehydration based on hemolysis assays. Oxygen dissociation curves for the desiccated/rehydrated RBCs showed a left shift compared to fresh RBCs (pO2 = 17 mmHg vs. 26 mmHg, respectively). The desiccated/rehydrated RBCs also showed an increase in methemoglobin compared to fresh RBCs (4.5% vs 0.9%, respectively). 2,3-Diphosphoglycerate concentration of the desiccated/rehydrated RBCs was reduced by 20%. In conclusion, although this RBC dehydration process preserves RBC integrity and hemoglobin oxygen binding properties better than most other dehydration techniques described so far, further optimization and long-term studies are needed to make this procedure acceptable for human transfusion.

Transporting Mammalian Cells at Ambient Temperature:A Viable Alternative to Dry Ice

The most common method of shipping cells between institutes and companies is sending them frozen, usually treated with anti-freeze solution (most commonly DMSO because it is less toxic than many alternatives), and then packaging them in dry ice for shipment. However many countries place restrictions on dry ice shipments. An alternative to shipping frozen cell vials is to send flasks of growing cells in media. This also has problems because cells in media have limited viability and the flasks can leak. Here we report on an alternative method for shipping viable cells at ambient temperature without dry ice or in media filled flasks. In this study we report on the development and properties of HemSol?. This is an inexpensive, eco-friendly and protects cell integrity at ambient temperature while maintaining viability. We have previously shown that HemSol? protects platelet and RBC function in cold storage and circulating tumor cells up to 6 days. Therefore we wanted to know if HemSol? could also be used to transport live cells. Since HemSol? is a liquid, we experimented with encasing the cells with HemSol? and gelatin so as to prevent dry ice shipment of cells and circumvent the shipping of cells in media. We performed mock shipping experiments where cells were stored in HemSol? gel kept at room temperature on a lab benchtop and cells stored in dry ice was also kept on lab benchtop for up to 2 days. After the mock shipping period, we analyzed cells for their functions. Our results show that cells in HemSol? gel have greater than 95% viability and restored biological functions in 2 hours, whereas, cells shipped in dry ice required more than 24 hours to recover and needed media change to remove the DMSO.