title: Structural characteristics of small intestinal submucosa constructs dictate          in vivo         incorporation and angiogenic response.
abstract: The rate of angiogenesis and cellular infiltration into degradable biomaterials determines scaffold persistence in vivo. The ability to tune the degradation properties of naturally derived biomaterials has been a popular goal in tissue engineering, yet has often depended on chemical crosslinking. Small intestinal submucosa (SIS) is a naturally derived, collagen-based, bioactive scaffold that has broad clinical success in many therapeutic applications. Two methods for producing multilayer, non-crosslinked SIS constructs were compared in vitro and in vivo. Traditional and cryo SEM, mercury intrusion porosimetry, and a novel enzymatic degradation assay determined that lyophilization produced an open, porous scaffold, in contrast to the collapsed, denser structure of SIS constructs produced using a vacuum press process. The angiogenic responses to lyophilized and vacuum-pressed SIS constructs were evaluated in vivo using a subcutaneous implant assay in mice. Explanted samples were compared after 7 and 21 days using fluorescence microangiography and light microscopy. Capacity of the implant neovasculature was also determined. These experiments revealed that the lyophilized SIS was infiltrated and vascularized more rapidly than the vacuum pressed. These data demonstrate the tunable incorporation of a non-crosslinked ECM-based biomaterial, which may have implications for the persistence of this degradable scaffold in tissue engineering.
authors.affiliation: Cook Biotech Incorporated, West Lafayette IN 47906, USA.
authors.forename: Abram Daved
authors.initials: AD
authors.lastname: Janis
authors.forename: Chad C
authors.initials: CC
authors.lastname: Johnson
authors.forename: David M
authors.initials: DM
authors.lastname: Ernst
authors.forename: Andrew O
authors.initials: AO
authors.lastname: Brightman
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D020285:Cryoelectron Microscopy; D005451:Fluorescein Angiography; D005612:Freeze Drying; D007413:Intestinal Mucosa / Q000098:blood supply / Q000502:physiology; D007421:Intestine, Small / Q000098:blood supply / Q000502:physiology*; D051379:Mice; D018919:Neovascularization, Physiologic
chemical_list: D001672:Biocompatible Materials