Fig. 2.

Effects of serum-free good manufacturing practices (GMP) compatible culture conditions on explant-derived cell (EDC) phenotype. Representative brightfield images of plated cardiac tissue fragments and EDC outgrowth under 20% serum conditions. a 1 day post-plating. b 3 days post-plating. c 7 days post-plating. Representative brightfield images of plated cardiac tissue fragments and EDC outgrowth under serum-free conditions. d 1 day post-plating. e 3 days post-plating. f 7 days post-plating. g Flow cytometry demonstrating that cells cultured in SF STD env conditions were smaller and more homogenous than cells cultured in serum STD env conditions. h Immunohistochemical staining for the cell cycle-associated protein Ki67 in conjunction with DAPI (left panel). Senescence-associated beta-galactosidase+ (β-Gal+) EDCs identified under phase-contrast microscopy by the presence of intracellular hydrolyzed X-galactosidase (right panel). i, j Flow cytometry analysis of phenotypic composition of EDCs. k Effect of cell culture conditions on the ability of EDCs to stimulate human umbilical vein endothelial cells (HUVECs) tubule formation (left panel) or attract circulating angiogenic cells (CACs) across a transwell membrane (right panel; expressed as fold change number of migrated cells compared to basal media containing 100 ng vascular endothelial growth hormone (VEGF; normalization control)). *p ≤ 0.05, **p ≤ 0.01, n = 4 to 5 cell cultures per group. abcg2, ATP-binding cassette sub-family G member 2; cad11, Cadherin-11; DDR2, discoidin domain receptor tyrosine kinase 2; Lin, hematological lineage cocktail; PDGFR, platelet-derived growth factor receptor; SSEA-1, stage-specific embryonic antigen-1