title: (Electron) microscopic observations on tissue integration of collagen-immobilized polyurethane.
abstract: The foreign body reactions to collagen-immobilized polyurethane (PU-CI) films during subcutaneous implantation in rats were characterized. The underlying concept is that collagen-immobilization will improve the tissue integration. Since the method of collagen-immobilization involves the covalent coupling of collagen to an acrylic acid (AA) based surface graft, both non-modified PU and PU-AA were used as controls. Bare PU has a flat surface, whereas both PU-AA and PU-CI displayed a slightly roughened surface. Implantation showed that PU-CI induced early after implantation a far more intense foreign body reaction than PU and PU-AA. This reaction consisted of increased presence of fibrin, granulocytes and macrophages. Roughening of the surface as with PU-AA induced only a small increase in fibrin formation and cellular migration. At day 5 the reaction to PU-CI had slowed down; giant cell formation now slowly started but was decreased compared to PU and PU-AA. At day 10 capsules around each type of material looked similar, but in contrast to PU. PU-CI films could no longer be dissected from their capsules. Only at week 3 this also occurred with PU, at which time point again similar capsules with the three materials were observed. At week 6, of the three materials PU-CI showed the thinnest capsule with most immediate adherence of connective tissue. These results show that collagen-immobilization of PU increased the early tissue reaction and therefore the tissue integration. The thin capsule observed at 6 weeks may be beneficial in e.g. infectious circumstances, when easy access for immune reactions is needed. This, and the long-term performance of PU-CI will be a matter of future investigations.
authors.affiliation: Department of Medical Biology, Groningen University, The Netherlands. p.b.van.wachem@med.rug.nl
authors.forename: P B
authors.initials: PB
authors.lastname: van Wachem
authors.forename: M
authors.initials: M
authors.lastname: Hendriks
authors.forename: E H
authors.initials: EH
authors.lastname: Blaauw
authors.forename: F
authors.initials: F
authors.lastname: Dijk
authors.forename: M L P M
authors.initials: ML
authors.lastname: Verhoeven
authors.forename: P T
authors.initials: PT
authors.lastname: Cahalan
authors.forename: M J A
authors.initials: MJ
authors.lastname: van Luyn
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D002465:Cell Movement; D003094:Collagen / Q000737:chemistry*; D005337:Fibrin / Q000737:chemistry; D006098:Granulocytes / Q000648:ultrastructure; D008264:Macrophages / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D011140:Polyurethanes / Q000737:chemistry*; D051381:Rats; D013997:Time Factors
chemical_list: D001672:Biocompatible Materials; D011140:Polyurethanes; D005337:Fibrin; D003094:Collagen