2.1. Primary Human Dermal Fibroblasts

Commercially available primary human dermal fibroblasts (derived from adult skin of single donor) (NHDF-Ad, CC-2511; Lonza, Basel, Switzerland) were cultured as previously described [13] in complete fibroblast cell medium (Fibroblast Cell Basal Medium), supplemented with 2% fetal bovine serum, 0.1% r-human fibroblast growth factor-B, 0.1% insulin, 0.1% gentamicin sulphate/amphotericin-B (Clonetics™ FGM™-2 Bullet Kit™; Lonza, Basel, Switzerland). Sub-cultivation was performed at approximately 80% confluence using the “ReagentPack Subculture Reagent Kit” according to the manufacturer instructions (Lonza, Basel, Switzerland).