Fibroblasts are mesenchymal cells derived from the embryonic mesoderm. They have been extensively used for a wide range of cellular and molecular studies as they are one of the easiest types of cells to grow in culture. Their durability also makes them amenable to a variety of manipulations ranging from studies employing gene transfection to microinjection. There is evidence showing that fibroblasts in various organs are intrinsically different. Specifically, pulmonary artery adventitial fibroblasts (PAAF) are important modulators of vascular wall function. During pathological conditions, such as hypoxia-induced pulmonary hypertension, HPAAF become proliferative which contributes to adventitial thickening. HPAAF from ScienCell Research Laboratories are isolated from human pulmonary artery. HPAAF are cryopreserved at passage one and delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. HPAAF are characterized by spindle morphology and by immunofluorescence with antibody specific to fibronectin. HPAAF are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HPAAF are guaranteed to further expand for 15 population doublings under the conditions provided by ScienCell Research Laboratories. Recommended Medium It is recommended to use Fibroblast Medium (FM, Cat. #2301) for culturing HPAAF in vitro.