Red cell supernatant effects on endothelial cell function and innate immune activation is influenced by donor age and sex

Background and objectives Blood donor characteristics significantly affect the pre‐storage and post‐storage quality of red cell concentrates (RCCs). This study investigated the impact of donor age and sex on RCC characteristics and the effect of RCC supernatants on the vascular endothelium and monocytes. Materials and methods RCC units selected from four donor groups based on donor age and sex (male ≤ 30‐years old (yo), male ≥ 60‐yo, female ≤ 30‐yo and female ≥ 60‐yo) were stored at 1–6°C and tested on day 7, 21 and 42. RCC supernatants were analysed for the number, concentration and size of extracellular vesicles (EVs). Human vein endothelial cells (HUVECs) monolayers were incubated with RCC supernatants and assessed for expression of vascular cell adhesion molecule‐1 (VCAM‐1) and E‐selectin by flow cytometry as well as endothelial permeability using a trans‐epithelial‐electrical‐resistance assay. Monocytes and HUVECs were incubated with RCC supernatants and supernatants assayed for cytokines/chemokines. Results RCCs from female donors were found to have lower unit volume, haemoglobin content and haematocrit compared to RCCs from male donors (P