Observations on the microvasculature of bone defects filled with biodegradable nanoparticulate hydroxyapatite.
The microvascularization of metaphyseal bone defects filled with nanoparticulate, biodegradable hydroxyapatite biomaterial with and without platelet factors enrichment was investigated in a minipig model. Results from morphological analysis and PECAM-1 immunohistochemistry showed the formation of new blood vessels into the bone defects by sprouting and intussusception of pre-existing ones. However, no significant differences were observed in the microvascularization of the different biomaterials applied (pure versus platelet factors-enriched hydroxyapatite), concerning the number of vessels and their morphological structure at day 20 after operation. The appearance of VEGFR-2 positive endothelial progenitor cells in the connective tissue between hydroxyapatite particles was also found to be independent from platelet factors enrichment of the hydroxyapatite bone substitute. In both groups formation of lymphatic vessels was detected with a podoplanin antibody. No differences were noted between HA/PLF- and HA/PLF+ implants with respect to the podoplanin expression level, the staining pattern or number of lymphatic vessels. In conclusion, the present study demonstrates different mechanisms of blood and lymphatic vessel formation in hydroxyapatite implants in minipigs.
Kilian
Olaf
O
Department of Trauma Surgery, University of Giessen, Rudolf-Buchheim-Strasse 7, 35392 Giessen, Germany. olaf.kilian@chiru.med.uni-giessen.de
Wenisch
Sabine
S
Karnati
Srikanth
S
Baumgart-Vogt
Eveline
E
Hild
Anne
A
Fuhrmann
Rosemarie
R
Jonuleit
Tarja
T
Dingeldein
Elvira
E
Schnettler
Reinhard
R
Franke
Ralf-Peter
RP
D000818:Animals; D001672:Biocompatible Materials / Q000378:metabolism / Q000627:therapeutic use; D015153:Blotting, Western; D001847:Bone Diseases / Q000473:pathology / Q000628:therapy*; D018786:Bone Substitutes / Q000378:metabolism / Q000627:therapeutic use*; D017886:Durapatite / Q000378:metabolism / Q000627:therapeutic use*; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D007150:Immunohistochemistry; D020007:Implants, Experimental; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D018919:Neovascularization, Physiologic / Q000187:drug effects; D016348:Osseointegration / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine
D001672:Biocompatible Materials; D018786:Bone Substitutes; D017886:Durapatite