Skin biopsies were obtained in the UM Clinical Research Unit. Samples were dissociated in trypsin, expanded in fibroblast medium comprising Dulbecco's Modified Eagle Medium (DMEM, 11965–092; Invitrogen, Grand Island, NY, USA) containing 10% heat-inactivated fetal bovine serum (Invitrogen, 10082–147), 1% non-essential amino acids (NEAA) (Invitrogen, 11140–050), 2 mM glutamax (Invitrogen, 35050–061) and 1 × Penicillin/Streptomycin solution (Invitrogen, 15140–122) to obtain dermal fibroblasts. Stock fibroblasts from each patient were banked and cells were analyzed for their expression of fibroblast-restricted genes, pluripotency factors, lineage markers and mycoplasma.
