title: Connexin 43 expression of foreign body giant cells after implantation of nanoparticulate hydroxyapatite.
abstract: In bone a role of connexin 43 has been implicated with the fusion of mononuclear precursors of the monocyte/macrophage lineage into multinucleated cells. In order to investigate the putative role of connexin 43 in formation of bone osteoclast-like foreign body giant cells which are formed in response to implantation of biomaterials, nanoparticulate hydroxyapatite had been implanted into defects of minipig femura. After 20 days the defect areas were harvested and connexin 43 expression and synthesis were investigated by using immunohistochemistry, Western Blot, and in situ hybridization within macrophages and osteoclast-like foreign body giant cells. Morphological analysis of gap junctions is performed ultrastructurally. As shown on protein and mRNA level numerous connexin 43 positive macrophages and foreign body giant cells (FBGC) were localized within the granulation tissue and along the surfaces of the implanted hydroxyapatite (HA). Besides, the formation of FBGC by fusion of macrophages could be shown ultrastructurally. Connexin 43 labeling observed on the protein and mRNA level could be attributed to gap junctions identified ultrastructurally between macrophages, between FBGC, and between FBGC and macrophages. Annular gap junctions in the cytoplasm of FBGC pointed to degradation of the channels, and the ubiquination that had occurred in the course of degradation was confirmed by Western blot analysis. All in all, the presently observed pattern of connexin 43 labeling refers to an functional role of gap junctional communication in the formation of osteoclast-like foreign body giant cells formed in response to implantation of the nanoparticulate HA.
authors: Institute of Veterinary Anatomy, University of Giessen, Frankfurter Str 98, 35392, Giessen, Germany. katja.a.herde@vetmed.uni-giessen.de
authors: Katja
authors: K
authors: Herde
authors: Sonja
authors: S
authors: Hartmann
authors: Ralph
authors: R
authors: Brehm
authors: Olaf
authors: O
authors: Kilian
authors: Christian
authors: C
authors: Heiss
authors: Anne
authors: A
authors: Hild
authors: Volker
authors: V
authors: Alt
authors: Martin
authors: M
authors: Bergmann
authors: Reinhard
authors: R
authors: Schnettler
authors: Sabine
authors: S
authors: Wenisch
mesh_terms: D000135:Acid Phosphatase / Q000737:chemistry; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001842:Bone and Bones / Q000378:metabolism; D018031:Connexin 43 / Q000096:biosynthesis*; D017886:Durapatite / Q000737:chemistry*; D017629:Gap Junctions / Q000378:metabolism*; D015743:Giant Cells, Foreign-Body / Q000378:metabolism*; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000737:chemistry; D008264:Macrophages / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D010010:Osteoclasts / Q000378:metabolism; D013552:Swine; D013556:Swine, Miniature; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D001672:Biocompatible Materials; D018031:Connexin 43; D007527:Isoenzymes; D017886:Durapatite; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase