Published in

Elsevier, Best Practice and Research: Clinical Endocrinology and Metabolism, 3(26), p. 291-302, 2012

DOI: 10.1016/j.beem.2011.10.002

Links

Tools

Export citation

Search in Google Scholar

Role of insulin-like growth factor-1 (IGF-1) pathway in the pathogenesis of Graves’ orbitopathy

Journal article published in 2012 by Terry J. Smith ORCID, Laszlo Hegedüs, Raymond S. Douglas
This paper is available in a repository.
This paper is available in a repository.

Full text: Download

Green circle
Preprint: archiving allowed
Orange circle
Postprint: archiving restricted
Red circle
Published version: archiving forbidden
Data provided by SHERPA/RoMEO

Abstract

The etiology of Graves’ orbitopathy (GO) remains enigmatic and thus controversy surrounds its pathogenesis. The role of the TSH receptor (TSHR) and the activating antibodies directed against it in the hyperthyroidism of Graves’ disease (GD) is firmly established. Less well elucidated is what part the TSHR pathway might play in the development of GO. Also uncertain is the participation of other cell surface receptors in the disease. Elevated levels of IGF-1 receptor (IGF-1R) have been found in orbital fibroblasts as well as B and T cells from patients with GD. These abnormal patterns of IGF-1R display are also found in rheumatoid arthritis and carry functional consequences. In addition, activating IgGs capable of displacing IGF-1 from IGF-1R have also been detected in patients with these diseases. IGF-1R forms a complex with TSHR which is necessary for at least some of the non-canonical signaling observed following TSHR activation. Functional TSHR and IGF-1R have also been found on fibrocytes, CD34+ bone marrow-derived cells from the monocyte lineage. Levels of TSHR on fibrocytes greatly exceed those found on orbital fibroblasts. When ligated by TSH or M22, a TSHR-activating monoclonal antibody, fibrocytes produce extremely high levels of several cytokines and chemokines. Moreover, fibrocytes infiltrate both the orbit and thyroid in GD. In sum, based on current evidence, IGF-1R and TSHR can be thought of as “partners in crime”. Involvement of the former probably transcends disease boundaries, while TSHR may not.