title: Mesenchymal stem cell adhesion to cardiac microvascular endothelium: activators and mechanisms.
abstract: Circulating stem cells home within the myocardium, probably as the first step of a tissue regeneration process. This step requires adhesion to cardiac microvascular endothelium (CMVE). In this study, we studied mechanisms of adhesion between CMVE and mesenchymal stem cells (MSCs). Adhesion was studied in vitro and in vivo. Isolated 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate-labeled rat MSCs were allowed to adhere to cultured CMVE in static and dynamic conditions. Either CMVE or MSCs were pretreated with cytokines [IL-1beta, IL-3, IL-6, stem cell factor, stromal cell-derived factor-1, or TNF-alpha, 10 ng/ml]. Control or TNF-alpha-treated MSCs were injected intracavitarily in rat hearts in vivo. In baseline in vitro conditions, the number of MSCs that adhered to CMVE was highly dependent on the flow rate of the superfusing medium but remained significant at venous and capillary shear stress amplitudes. Activation of both CMVE and MSCs with TNF-alpha or IL-1beta before adhesion concentration dependently increased adhesion of MSCs at each studied level of shear stress. Consistently, in vivo, activation of MSCs with TNF-alpha before injection significantly enhanced cardiac homing of MSCs. TNF-alpha-induced adhesion could be completely blocked by pretreating either CMVE or MSCs with anti-VCAM-1 monoclonal antibodies but not by anti-ICAM-1 antibodies. Adhesion of circulating MSCs in the heart appears to be an endothelium-dependent process and is sensitive to modulation by activators of both MSCs and endothelium. Inflammation and the expression of VCAM-1 but not ICAM-1 on both cell types have a regulatory effect on MSC homing in the heart.
authors.affiliation: Laboratory of Physiology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
authors.forename: Vincent F M
authors.initials: VF
authors.lastname: Segers
authors.forename: Ivan
authors.initials: I
authors.lastname: Van Riet
authors.forename: Luc J
authors.initials: LJ
authors.lastname: Andries
authors.forename: Katrien
authors.initials: K
authors.lastname: Lemmens
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Demolder
authors.forename: Ann J M L
authors.initials: AJ
authors.lastname: De Becker
authors.forename: Mark M
authors.initials: MM
authors.lastname: Kockx
authors.forename: Gilles W
authors.initials: GW
authors.lastname: De Keulenaer
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D003331:Coronary Vessels / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism*
chemical_list: D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1