On Day 1, 96-well phenotype microarray plates (PM-M1, Biolog; Supplementary Table 2) had 30 µl of IFM-1 (Biolog) containing 10% dialysed FBS and 0.3 mM glutamine added and then incubated overnight at 37°C/5% CO2. On Day 2, 96-well half-area plates were coated with 50 µl of fibronectin (0.25 µg/ml in PBS) for 60 min at room temperature and then washed with 100 µl PBS. Confluent fibroblasts were harvested by trypsinisation (Lonza) and the cell number was determined using a trypan blue dye exclusion test and a Countess automated cell counter (Invitrogen). Using the PM-M1 plates incubated the previous day, the IFM-1 fluid now containing the different metabolites was transferred to the corresponding wells on the fibronectin-coated plates. The cells were resuspended at 800 000 cells per ml of IFM-1 media and 20 µl, (equivalent to 16 000 cells), was transferred to each well of the substrate plate and then incubated at 37°C/5% CO2 for 40 h. After the stated incubation time, 10 µl of redox dye mix MA (Biolog) was added to each well and the plates sealed with sterile Seal-Plate film to stop gas transfer. Dye colour change was measured every 20 min for 120 min and then every 60 min up to 300 min using a BMG Omega Pherastar at 590/790 nM (790 nM was removed from 590 nM to account for background values). After incubation, the plates were washed three times with 100 µl of PBS and stored overnight at −80°C prior to cell counting. All results were normalized to cell number by addition of CyQUANT® (Invitrogen) to each well as per the manufacturer’s instructions (1/400 dilution of the dye in HBSS buffer, 100 µl per well) and fluorescence was measured using a BMG Omega FLUOstar.