No evidence for the expression of renin-angiotensin-aldosterone system in otosclerotic stapes footplates.
BACKGROUND
Recent studies have reported genetic associations between with single nucleotide polymorphism (SNP) of the several genes of the renin-angiotensin-aldosterone (RAA) system in otosclerosis without the confirmation of RAA system expression in human stapes footplates. There are conflicting results. These results are conflicting because RAA system expression has been attributed exclusively to neural, vascular, and renal tissues, exclusively.


METHODS
Ankylotic stapes footplates (n = 20), cortical bone fragments (n = 10), and human kidney tissue specimens (n = 10) were processed to hematoxylin-eosin (HE) staining and RAA system-specific immunofluorescent assay (IFA), respectively.


RESULTS
Histologic diagnosis of otosclerosis was established in all ankylotic stapes footplates. Histologically active- (n = 13) and inactive (n = 7) foci of otosclerosis were consequently characterized by negative immunoreactions for renin, angiotensin converting enzyme (ACE), angiotensin-II (AT-II), and angiotensin-II receptor (AT-IIR), consequently. In cortical bones, a considerable RAA system expression was observed confirmed in the perivascular bone marrow progenitor cells. Kidney specimens, applied as positive controls, showed intense RAA system-specific immunoreactions.


CONCLUSIONS
Concerning current observations, the 4 studied members of RAA system that did not display active expression were not expressed at protein level in otosclerotic stapes footplates. This phenomenon was independent from the histologic activity of otosclerosis. Between these conditions, the etiologic role of RAA system is questionable in the pathogenesis of otosclerosis.
ENT Department, Bajcsy-Zsilinszky Hospital, Budapest, Hungary.
Balázs
B
Liktor
Péter
P
Csomor
Csaba Sándor
CS
Szász
István
I
Sziklai
Tamás
T
Karosi
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010040:Otosclerosis / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013199:Stapes / Q000378:metabolism* / Q000473:pathology; D013201:Stapes Surgery / Q000009:adverse effects; D055815:Young Adult
D012333:RNA, Messenger