Connective tissue is derived from the mesoderm and is critical for maintaining the structural integrity of the body. Fibroblasts, the predominant cells found in connective tissue, continuously secrete diverse components of the extracellular matrix. Fibroblasts exhibit unique morphology and functional properties that depend on their site of origin and physiological status.Primary Human Fibroblasts from PromoCell are isolated from normal human juvenile foreskin or from adult skin from various sites, including adult lung tissue and aortic adventitial tissue. Soon after isolation, Human Fibroblasts are cryopreserved at passage 2 (P2) using proprietary, serum-free freezing medium, Cryo-SFM. Each thawed cryovial contains at least 500,000 viable cells. Human Fibroblasts are also available as proliferating cell cultures made from cryopreserved cells that have been thawed and cultured for three days. Cultivation Protocol for Primary Human Fibroblasts. Fibroblast Growth Media is available in three different formulations: Fibroblast Growth Medium is a serum-free medium developed for in vitro cultivation of fibroblasts. This medium is optimized for primary human cells, but can also be used for bovine, porcine, and rat fibroblasts, as well as fibroblast cell lines. Fibroblast Growth Medium 2 is a low-serum medium developed for the in vitro cultivation of adult Human Fibroblasts. The medium is optimized for primary human cells, but can also be used for bovine, porcine, and rat fibroblasts, as well as fibroblast cell lines.Fibroblast Growth Medium 3 was developed specifically for the in vitro cultivation of adult Human Cardiac Fibroblasts (HCF).