AbstractsBiology & Animal Science

Blood transfusion is an essential part of modern healthcare. It is a life-saving intervention, which unfortunately, can have adverse clinical effects. Red blood cell transfusion is e.g. used in foetal medicine, in cases of trauma, in surgeries treating heart diseases and as a consequence of cancer therapy. Red blood cell concentrates are stored at 2-6 °C for up to 42 days. Storage of RBC concentrates makes it possible to have an inventory of relatively safe units available at most times. However longer storage results in damage to the RBCs, referred to as storage lesion. Storage lesions of RBCs are all the changes, both physical and metabolic, that occur to the RBC during the storage period. The longer the RBCs are stored, the more storage lesions they acquire, and a smaller proportion survives when it is transfused into the patient. Erythrophagocytosis is the process by which old or damaged RBCs are cleared in the body by phagocytic cells. The clinical implications of transfusing RBCs that have been stored for longer times are not well understood but are currently being studied vigorously. A recent meta-analysis of 21 studies concluded that a significantly increased mortality is associated with the transfusion of old blood compared to new blood. However, recent and larger studies found no links between older transfused blood and increased mortality. Whether old blood carries increased risk has been debated for quite some time and recent studies need to be reviewed thoroughly. The question remains whether results from numerous studies warrant changes in current clinical practices of blood transfusion. The objective of this study was to analyse how the age of stored RBCs affects erythrophagocytosis using the human monocytic cell line THP-1. To achieve this, THP-1 cells were co-cultured with PKH26-labelled RBCs and analysed with flow cytometry and fluorescence microscopy. Negligible phagocytosis was seen when undifferentiated THP-1 cells were used. However, differentiated THP-1 cells readily phagocytosed PKH26-labelled RBCs. Comparison of RBC units stored for 7, 19 and 40 days revealed minor differences. The cell line THP-1 is sensitive to overgrowth and changes in culture conditions and as a result it readily loses its ability to phagocytose. This is avoided by using differentiated THP-1 cells. However, this introduces considerable variability to the assay. The red fluorescence seen in the flow cytometric analysis of the erythrophagocytosis assay was the result of phagocytosis of PKH26-labelled RBCs. This was confirmed with photomicrographs and the inhibition of phagocytosis with the use of cytochalasin D. From our results it is not possible to conclude that longer storage affects erythrophagocytosis. Further development of the erythrophagocytosis assay is necessary. Blóðgjöf er mikilvægur hlekkur í nútíma læknisfræðilegri meðferð. Þrátt fyrir að blóðgjöf geti svo sannarlega oft verið lífgjöf, geta afleiðingar blóðgjafar einnig valdið vandamálum. Rauðkornaþykkni er gefið við ýmsar aðstæður, s.s. vegna áverka, við…