Safety of the blood supply

Putting the spotlight on donation-related risks and donor safety - are we succeeding in protecting donors?

BACKGROUND AND OBJECTIVE

The European consortium project TRANSPOSE (TRANSfusion and transplantation: PrOtection and SElection of donors) aimed to assess and evaluate the risks to donors of Substances of Human Origin (SoHO), and to identify gaps between current donor vigilance systems and perceived risks.

MATERIALS AND METHODS

National and local data from participating organizations on serious and non-serious adverse reactions in donors were collected from 2014 to 2017. Following this, a survey was performed among participants to identify risks not included in the data sets. Finally, participants rated the risks according to severity, level of evidence and prevalence.

RESULTS

Significant discrepancies between anticipated donor risks and the collected data were found. Furthermore, many participants reported that national data on adverse reactions in donors of stem cells, gametes, embryos and tissues were not routinely collected and/or available.

CONCLUSIONS

These findings indicate that there is a need to further develop and standardize donor vigilance in Europe and to include long-term risks to donors, which are currently underreported, ensuring donor health and securing the future supply of SoHO.

Storability of porcine blood in forensics: How far should we go?

Previous studies on the storability of porcine blood for bloodstain pattern analysis (BPA) focused on abattoir blood only and did not include measurements of viscoelasticity. Although known to provoke echinocyte formation, EDTA is widely used for BPA issues. We compared ageing samples taken from live pigs with abattoir blood and detected considerable differences in hematocrit (HCT), total protein and shear viscosity that even worsened with time. Upon storage, high shear viscosity continuously increased, resulting in a partial loss of the typical shear thinning property of blood. Furthermore, we explored CPDA-1, the gold standard in preserving red blood cells (RBCs), for storage of forensic samples. We found it to be a superior choice for anticoagulation, as the rise of high shear viscosity was attenuated compared to EDTA. When performing oscillation measurements, we found a sudden change of viscoelasticity of blood after 22 days, providing a cut-off for storage time. To highlight the importance of hematological and hemorheological changes upon cold storage, we performed simple drip pattern experiments. These tests revealed a tendency to smaller stain diameters and higher numbers of satellite spatter. While this contradicts expectations from elevated viscosity values, we associate this trend to microscopic inhomogeneities due to storage. We recommend CPDA-1 for prolonged storage of BPA samples and suggest the use of comprehensive test protocols including viscoelasticity for determination of the maximum shelf life of pig blood.

Evaluation of Stem Cell-Derived Red Blood Cells as a Transfusion Product Using a Novel Animal Model

Reliance on volunteer blood donors can lead to transfusion product shortages, and current liquid storage of red blood cells (RBCs) is associated with biochemical changes over time, known as ‘the storage lesion’. Thus, there is a need for alternative sources of transfusable RBCs to supplement conventional blood donations. Extracorporeal production of stem cell-derived RBCs (stemRBCs) is a potential and yet untapped source of fresh, transfusable RBCs. A number of groups have attempted RBC differentiation from CD34⁺ cells. However, it is still unclear whether these stemRBCs could eventually be effective substitutes for traditional RBCs due to potential differences in oxygen carrying capacity, viability, deformability, and other critical parameters. We have generated ex vivo stemRBCs from primary human cord blood CD34⁺ cells and compared them to donor-derived RBCs based on a number of in vitro parameters. In vivo, we assessed stemRBC circulation kinetics in an animal model of transfusion and oxygen delivery in a mouse model of exercise performance. Our novel, chronically anemic, SCID mouse model can evaluate the potential of stemRBCs to deliver oxygen to tissues (muscle) under resting and exercise-induced hypoxic conditions. Based on our data, stem cell-derived RBCs have a similar biochemical profile compared to donor-derived RBCs. While certain key differences remain between donor-derived RBCs and stemRBCs, the ability of stemRBCs to deliver oxygen in a living organism provides support for further development as a transfusion product.