Background: High blood levels of the chemokine eotaxin-1 (CCL11) have recently been associated with aging and dementia, as well as impaired memory and learning in humans. Importantly, eotaxin-1 was shown to pass the blood-brain-barrier (BBB) and has been identified as crucial mediator of decreased neurogenesis and cognitive impairment in young mice after being surgically connected to the vessel system of old animals in a parabiosis model. It thus has to be assumed that differences in eotaxin-1 levels between blood donors and recipients might influence cognitive functions also in humans. However, it is unknown if eotaxin-1 is stable during processing and storage of transfusion blood components. This study assesses eotaxin-1 concentrations in fresh-frozen plasma (FFP), erythrocyte concentrate (EC), and platelet concentrate (PC) in dependence of storage time as well as the donor’s age and gender.Methods: Eotaxin-1 was measured in FFP (n = 168), EC (n = 160) and PC (n = 8) ready-to-use for transfusion employing a Q-Plex immunoassay for eotaxin-1. Absolute quantification of eotaxin-1 was performed with Q-view software.Results: Eotaxin-1 was consistently detected at a physiological level in FFP and EC but not PC. Eotaxin-1 levels were comparable in male and female donors but increased significantly with rising age of donors in both, FFP and EC. Furthermore, eotaxin-1 was not influenced by storage time of either blood component. Finally, eotaxin-1 is subject to only minor fluctuations within one donor over a longer period of time.Conclusion: Eotaxin-1 is detectable and stable in FFP and EC and increases with donor’s age. Considering the presumed involvement in aging and cognitive malfunction, differences in donor- and recipient eotaxin-1 levels might affect mental factors after blood transfusion.

Background and Objectives Tissue inhibitor of metalloproteinases 2 (TIMP-2) is a protein suspected to be crucial in numerous physiological and pathological processes such as morphogenesis, tissue remodelling and metastasis suppression. In animal models, the administration of TIMP-2 to aged mice improved their cognitive functions. Therefore, one can hypothesize that differences in TIMP-2 levels between blood donors and recipients might influence cognitive functions also in humans. However, the stability of TIMP-2 during processing and storage of blood components for transfusion has not been intensively investigated so far. This study determined TIMP-2 concentrations in fresh-frozen plasma (FFP), erythrocyte concentrate (EC) and pathogen-inactivated platelet concentrate (PI-PC) depending on the donor's demographic factors age and gender.Materials and Methods Tissue inhibitor of metalloproteinases 2 was measured in FFP (n = 30), EC (n = 12) and PI-PC (n = 12) using a Q-Plex single-plex immunoassay for chemiluminescence-based detection. Absolute quantification of TIMP-2 was performed with Q-view software. Fresh umbilical cord plasma was used as a positive control.Results Tissue inhibitor of metalloproteinases 2 was detected in FFP (30/30 samples), EC (11/12 samples) and PI-PC (12/12 samples). The median TIMP-2 concentration in EC (17Á2 ng/ml; range: 0-26Á5 ng/ml) was significantly lower compared with FFP (63Á4 ng/ml; range: 44Á4-87Á3 ng/ml) or PI-PC (69Á9 ng/ml; range: 39Á9-83Á6 ng/ml). Across all blood components, TIMP-2 levels are comparable in male and female donors and independent of age.Conclusion Tissue inhibitor of metalloproteinases 2 is detectable and stable in FFP, PI-PC and, in low concentration, EC. It can be hypothesized that TIMP-2 will be transmitted to recipients during transfusion.

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