HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Lai, O. F. Articles by Khoo, D. H C Search for Related Content PubMed PubMed Citation Articles by Lai, O. F. Articles by Khoo, D. H C

Detection of thyroid peroxidase mRNA and protein in orbital tissue

¹ Departments of Clinical Research and ² Endocrinology, Singapore General Hospital, Outram Road, Singapore, Singapore 169608, ³ Singapore National Eye Center, 11 Third Hospital Avenue, Singapore, Singapore 168751 and ⁴ Faculte de Medecine Timone, U555 INSERM, 27 av Jean Moulin, 13005 Marseille, France

(Correspondence should be addressed to D H C Khoo; Email: geckhc{at}sgh.com.sg)

Objective: We have previously reported that the absence of thyroid peroxidase antibodies (TPOAb) in Graves’ disease (GD) was associated with an increased risk of Graves’ ophthalmopathy (GO). This observation raised the possibility that TPOAb could act as a protective factor. However, the presence of thyroid peroxidase (TPO) in the orbit has not been previously reported. The aim of this study was to confirm or exclude the presence of orbital TPO.

Methods and design: Relative TPO mRNA expression from GO (n = 6) and normal (n = 5) orbital fat tissue was determined using real-time PCR technique. Orbital fat in the normal group from blepharoplasty represents extraconal (anterior) fat. mRNA expression in fibroblasts grown from these tissues before and after adipocyte differentiation was also documented. Finally, Western blotting was carried out to verify translation of TPO mRNA transcripts.

Results and discussion: TPO transcripts were detected in the orbital fat tissue obtained from normal and GO subjects using the real-time PCR technique. TPO expression was increased in GO compared to normal (N) tissues. However, TPO expression in cultured fibroblasts was similar in both groups and adipogenesis did not appear to alter TPO expression. Protein was detected by Western blot analysis using the TPO MAB 47 (mAb 47). The predicted 110-kDa band was detected in orbital fat as well as in orbital fibroblasts. Our results suggest the presence of TPO in GO and N orbital tissues. We hypothesise that immune responses directed against orbital TPO might play a role in modulating the clinical expression of GO.