title: An in-vivo model to interrogate the transition from acute to chronic inflammation.
abstract: This study describes the modulation of the rodent foreign body giant cell (FBGC) response to subcutaneously implanted, biodegradable poly(lactide-co-glycolide)/calcium phosphate (PLGA/CaP) composites by application of a thin surface coat of calcium phosphate. Macroporous PLGA/CaP composite scaffolds, with interconnecting macroporosity, were half coated with a 3mm thick layer of CaP by immersion in simulated body fluid. Half-coated scaffolds were implanted subcutaneously in the dorsum of male Wistar rats for 1, 4 and 8 weeks. Specimens were embedded in paraffin and tissue sections evaluated by light microscopy with particular reference to the FBGC response. Histomorphometry revealed that FBGCs were in contact with 6% (+/- 3.5%) of the uncoated half, at 1 week, but no FBGCs were seen on the coated half. By 4 weeks, FBGCs were seen on both the uncoated and coated halves of the scaffolds with 87% (+/-10%) and 36% (+/-4%) FBGC/polymer contact respectively. By 8 weeks these FBGC contact percentages had risen to 97% (+/-0.45%) in the case of the uncoated halves of scaffolds, but decreased to 22% (+/-4%) in the case of the CaP-coated halves. Thus the CaP coating abrogated the FBGC response to the underlying polymer. Such a model may prove useful in providing an experimental system whereby both the mechanisms of biocompatibility and the transition from acute to chronic inflammation could be interrogated.
authors.affiliation: Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada. davies@ecf.utoronto.ca.
authors.forename: D
authors.initials: D
authors.lastname: Lickorish
authors.forename: J
authors.initials: J
authors.lastname: Chan
authors.forename: J
authors.initials: J
authors.lastname: Song
authors.forename: J E
authors.initials: JE
authors.lastname: Davies
mesh_terms: D020341:Absorbable Implants / Q000009:adverse effects*; D000208:Acute Disease; D000818:Animals; D002130:Calcium Phosphates; D002908:Chronic Disease; D020099:Coated Materials, Biocompatible; D004195:Disease Models, Animal; D005549:Foreign-Body Reaction / Q000473:pathology* / Q000503:physiopathology*; D015743:Giant Cells, Foreign-Body / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D019344:Lactic Acid; D008264:Macrophages / Q000473:pathology; D008297:Male; D008855:Microscopy, Electron, Scanning; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D023822:Tissue Engineering
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C020243:calcium phosphate