Cell culture
HPASMCs (Lonza, Cat. No. CC-2581) were cultured in T75 tissue culture flasks coated with 0.2% porcine gelatin (Sigma, Cat. no. G1890) in smooth muscle cell growth medium 2 (SmGM-2, PromoCell, Cat. no. C-22062), supplemented with 5% FBS and growth factor supplement (PromoCell, Cat. no. C-39267) and antibiotics. Cells were acquired at passage 3 and were used for experiments in passages 4–6. Donor information is provided in Supplementary Table 2. For HPAEC and HPASMC co-culture, ECGM-2 medium was supplemented with 10% foetal bovine serum (FBS). VEGF, ascorbic acid, heparin, and hydrocortisone, known to inhibit HPASMC proliferation, were excluded.
Blood-derived human endothelial cells
... ECFCs were cultured in 1% porcine gelatin-coated T75 tissue culture flasks (Sigma, Cat. no. G1890) in EGM-2 medium (CC-3156, Lonza Biologics, Slough, UK), supplemented with growth factors (CC-4176, EGMTM-2 bullet kit, Lonza), 10% FBS (HyClone, Thermo Scientific, South Logan, UT, USA) and 1% antibiotic/antimycotic solution (Gibco, Invitrogen, Paisley, UK). All ECFCs were used between passages 3 and 6.