Immunohistochemical evidence of BMP-2, -4 and -7 activity in otospongiosis.
CONCLUSIONS
This study is the first to show that bone morphogenetic proteins (BMP)-2, -4 and -7 play a role in active phase otosclerotic bone remodelling (otospongiosis).


OBJECTIVE
The role of BMPs in various tissue growth and repair mechanisms is an ongoing topic in the literature. BMP-2, -4 and -7 are known to be of major importance in bone formation and repair. Their role in otosclerotic bone transformation has not been analysed previously. The main goal of this study was to perform an immunohistological analysis of BMP-2, -4 and -7 in otoclerosis.


METHODS
Parts of the stapedial footplates, collected during partial stapedectomies in 30 patients with clinical otosclerosis, were analysed for histological otosclerotic lesions after staining haematoxylin and eosin. Immunohistochemical analysis was performed using polyclonal IgG antibodies for BMP-2, -4 and -7, as well as biotinylated secondary antibodies, avidin-biotin-peroxidase complex reaction and alkaline phosphatase staining.


RESULTS
In all, 14 specimens contained otosclerosis; 3 of these were otospongiotic, 8 fibrotic, 2 sclerotic and 1 had both sclerotic and fibrotic lesions. Thus in total 14/30 specimens (47%) showed histological otosclerosis. Only the multiple osteoblasts and osteoclasts in those specimens exhibiting an otospongiotic phase showed distinct immunochemical staining for BMP-2, -4 and -7.
Lehnerdt
Goetz
G
Department of Otorhinolaryngology, University of Duisburg-Essen, Essen, Germany. goetz.lehnerdt@uni-due.de
Unkel
Claus
C
Metz
Klaus Alfred
KA
Jahnke
Klaus
K
Neumann
Andreas
A
D000328:Adult; D001853:Bone Marrow / Q000473:pathology; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000032:analysis*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D010006:Osteoblasts / Q000473:pathology; D010010:Osteoclasts / Q000473:pathology; D010040:Otosclerosis / Q000473:pathology* / Q000601:surgery; D012016:Reference Values; D013199:Stapes / Q000473:pathology; D013201:Stapes Surgery; D016212:Transforming Growth Factor beta / Q000032:analysis*
C525718:BMP2 protein, human; C525809:BMP4 protein, human; C525819:BMP7 protein, human; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D016212:Transforming Growth Factor beta