title: Macrophages play a key role in angiogenesis and adipogenesis in a mouse tissue engineering model.
abstract: We have previously described a mouse adipose tissue engineering model using a silicon chamber enclosing the superficial epigastric pedicle in a Matrigel based environment. We have shown that when Zymosan, a sterile inflammatory agent, is added to the chamber, angiogenesis and adipogenesis are significantly improved. As Zymosan interacts with toll-like receptors on macrophages, the role of macrophages in new tissue development in the tissue engineering chamber was assessed. Morphological and histological results showed that macrophages were presenting in high numbers at 2 weeks but had decreased significantly by 4 and 6 weeks in the chamber. Numerous immature new blood vessels had formed by 2 weeks, becoming more mature at 4 and 6 weeks. Immature adipocytes were visualized at 4 weeks and mature cells, at 6 weeks. To investigate the functional role of macrophages in the tissue engineering process, we knocked out the local macrophage population by inserting Clodronate liposomes in this chamber. This study shows for the first time that when macrophages are depleted, there is minimal new vascular and adipose tissue development. We propose a new theory for tissue engineering in which macrophages play a central role in both neovascularisation and adipogenesis.
authors.affiliation: 1 O'Brien Institute Melbourne , Fitzroy, Australia .
authors.forename: Heidi
authors.initials: H
authors.lastname: Debels
authors.forename: Laurence
authors.initials: L
authors.lastname: Galea
authors.forename: Xiao-Lian
authors.initials: XL
authors.lastname: Han
authors.forename: Jason
authors.initials: J
authors.lastname: Palmer
authors.forename: Nico
authors.initials: N
authors.lastname: van Rooijen
authors.forename: Wayne
authors.initials: W
authors.lastname: Morrison
authors.forename: Keren
authors.initials: K
authors.lastname: Abberton
mesh_terms: D050156:Adipogenesis; D000273:Adipose Tissue / Q000098:blood supply / Q000166:cytology / Q000378:metabolism; D000818:Animals; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D008297:Male; D051379:Mice; D018919:Neovascularization, Physiologic; D023822:Tissue Engineering; D051193:Toll-Like Receptors / Q000378:metabolism; D015054:Zymosan / Q000494:pharmacology
chemical_list: D051193:Toll-Like Receptors; D015054:Zymosan