Glycolysis in tip cell and non-tip cell HUVECs. (a) FACS sorting of HUVECs with the use of PE-conjugated anti-CD34 antibody. Non-tip cells were put back into culture and their CD34 expression was checked after 24 h showing a percentage of tip cells of 1%. Assessment of glycolysis (ECAR) (b) and uptake levels of 2-NBDG (100 µM) (c) in CD34- and CD34+ FACS-sorted HUVECs showed that the glycolysis rate was lower in tip cells. (d) GSEA metabolic pathway enrichment analysis showed an enrichment of the expression of glycolytic genes in non-tip cells as compared to tip cells. ECAR measurements are represented as fold change compared to basal ECAR levels in non-tip cells. mpH/min: milli-pH units per minute; ES: enrichment score; NES: normalized enrichment score. Results are shown as means ± SEM of experiments with HUVECs of at least 3 donors. *P < 0.05 and **P < 0.01 as compared to non-tip cells (Unpaired Student’s t-test).