title: In vitro effects of combined and sequential delivery of two bone growth factors.
abstract: Bone formation and repair occur by a complex cascade involving numerous growth factors and cytokines. In this study, two-layered heterogeneously loaded and crosslinked gelatin coatings were used to obtain combined and sequential delivery of two bone growth factors, BMP-2 and IGF-I, in cell cultures. Peak release from the top and bottom layers was localized around 1 and 6 days, respectively. For comparison, cells were also treated with soluble growth factors directly added to the culture medium. Pluripotent C3H10T1/2 (C3H) cells responded to soluble growth factor treatments with the greatest specific alkaline phosphatase (AP) activity resulting from addition of BMP-2 followed by IGF-I or by BMP-2+IGF-I. Altered loading and subsequent release of BMP-2 and IGF-I from gelatin coatings also affected AP activity in C3H cultures, and the coatings influenced AP activity and incorporation of calcium in the extracellular matrix of bone marrow stromal cell cultures. Early delivery of BMP-2 followed by increased release of BMP-2 and IGF-I after 5 days resulted in the largest, as well as earliest, elevation of AP activity and mineralized matrix formation compared to controls and other treatments. Simultaneous release of both growth factors from both layers did not significantly change AP activity or matrix calcium content compared to control coatings. These results demonstrate that temporally varying delivery of multiple growth factors can significantly affect cell behavior.
authors: Center for Biomedical Engineering, Wenner-Gren Laboratory, University of Kentucky, Lexington, KY 40506-0070, USA.
authors: A T
authors: AT
authors: Raiche
authors: D A
authors: DA
authors: Puleo
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects* / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage*; D002118:Calcium / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis / Q000737:chemistry; D004247:DNA / Q000378:metabolism; D003692:Delayed-Action Preparations / Q000008:administration & dosage* / Q000737:chemistry*; D005780:Gelatin / Q000737:chemistry*; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage*; D008297:Male; D008422:Materials Testing / Q000379:methods*; D051379:Mice; D008809:Mice, Inbred C3H; D039904:Pluripotent Stem Cells / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D016212:Transforming Growth Factor beta
chemical_list: C525719:Bmp2 protein, mouse; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D020099:Coated Materials, Biocompatible; D003692:Delayed-Action Preparations; D016212:Transforming Growth Factor beta; D007334:Insulin-Like Growth Factor I; D005780:Gelatin; D004247:DNA; D002118:Calcium