title: Hypoxic pre-conditioning increases the infiltration of endothelial cells into scaffolds for dermal regeneration pre-seeded with mesenchymal stem cells.
abstract: Many therapies using mesenchymal stem cells (MSC) rely on their ability to produce and release paracrine signals with chemotactic and pro-angiogenic activity. These characteristics, however, are mostly studied under standard in vitro culture conditions. In contrast, various novel cell-based therapies imply pre-seeding MSC into bio-artificial scaffolds. Here we describe human bone marrow-derived MSC seeded in Integra matrices, a common type of scaffold for dermal regeneration (SDR). We show and measured the distribution of MSC within the SDR, where cells clearly establish physical interactions with the scaffold, exhibiting constant metabolic activity for at least 15 days. In the SDR, MSC secrete VEGF and SDF-1α and induce transwell migration of CD34(+) hematopoietic/endothelial progenitor cells, which is inhibited in the presence of a CXCR4/SDF-1α antagonist. MSC in SDR respond to hypoxia by altering levels of angiogenic signals such as Angiogenin, Serpin-1, uPA, and IL-8. Finally, we show that MSC-containing SDR that have been pre-incubated in hypoxia show higher infiltration of endothelial cells after implantation into immune deficient mice. Our data show that MSC are fully functional ex vivo when implanted into SDR. In addition, our results strongly support the notion of hypoxic pre-conditioning MSC-containing SDR, in order to promote angiogenesis in the wounds.
authors.affiliation: Stem Cell Program, Department of Cell Biology and Human Anatomy, University of California, Davis Davis, CA, USA.
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Fierro
authors.affiliation: Department of Biological Sciences, California State University Sacramento, CA, USA.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: O'Neal
authors.affiliation: Stem Cell Program, Department of Cell Biology and Human Anatomy, University of California, Davis Davis, CA, USA.
authors.forename: Julie R
authors.initials: JR
authors.lastname: Beegle
authors.affiliation: Department of Plastic Surgery and Hand Surgery, University Hospital rechts der Isar, Technische Universität München Munich, Germany ; Facultad de Ciencias, FONDAP Center for Genome Regulation, Universidad de Chile Santiago, Chile.
authors.forename: Myra N
authors.initials: MN
authors.lastname: Chávez
authors.affiliation: Department of Biological Sciences, California State University Sacramento, CA, USA.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Peavy
authors.affiliation: Department of Dermatology, University of California, Davis Davis, CA, USA.
authors.forename: Roslyn R
authors.initials: RR
authors.lastname: Isseroff
authors.affiliation: Department of Plastic Surgery and Hand Surgery, University Hospital rechts der Isar, Technische Universität München Munich, Germany ; Facultad de Ciencias, FONDAP Center for Genome Regulation, Universidad de Chile Santiago, Chile ; Institute for Medical and Biological Engineering, Schools of Engineering, Biological Sciences and Medicine, Pontificia Universidad Católica de Chile Santiago, Chile.
authors.forename: José T
authors.initials: JT
authors.lastname: Egaña
keywords: angiogenesis; hypoxia; mesenchymal stem cells; scaffolds; wound healing