Background Thyroid-associated orbitopathy (TAO) causes inflammatory fibroproliferation of periocular connective tissues. We compared adipose tissue-derived stem/stromal cells (ADSCs) from three adipose depots of each patient with TAO on mesenchymal, myofibrogenic, adipogenic properties and associated hyaluronan (HA) synthesis.
Methods ADSCs were generated from periocular (eyelid, orbital) and subcutaneous (abdominal) adipose tissues of three patients with TAO. Mesenchymal markers were characterised by reverse transcription-PCR and immunofluorescent staining. A 3-week adipogenic induction was evaluated by Nile red staining and quantitative PCR (qPCR) of peroxisome proliferator-activated receptor (PPARγ), adiponectin and hyaluronan synthase (HAS)-2. A 7-day myofibrogenic induction was assayed by immunofluorescent staining and qPCR of α-smooth muscle actin (α-SMA).
Results ADSCs from all depots expressed similar levels of mesenchymal markers CD44, CD90 and CD105 (p=0.288, p=0.43 and p=0.837, respectively). After adipogenic induction, intracellular lipid increased for more than 32% and PPARγ mRNA showed more than twofold increase from all three depots. However, adiponectin and HAS-2 mRNA levels were significantly higher in the eyelid and orbital ADSCs than those from the subcutaneous ADSCs after induction (2.4×107, 3.9×106 folds vs below detection limit; 63.3-fold, 26.1-fold, vs 33% reduction, respectively; all p=0.002). Significantly more myofibroblasts and higher mRNA level of α-SMA were obtained from the orbital and eyelid compared with the subcutaneous ADSCs during myofibrogenic induction (80.2%, 70.6% vs 29.3%; 30.2-fold, 24.2-fold vs 1.7-fold, respectively; all p=0.002).
Conclusion ADSCs from different adipose depots of the same donors exhibited similar mesenchymal phenotypes but differed significantly in adipogenic, myofibrogenic potentials and associated HA synthesis. These depot-specific characteristics of ADSCs may contribute to site-specific adipose tissue involvement in TAO.
- experimental – laboratory
- stem cells
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Contributors JSCW, WKC, BF-LL, C-PP and KK-LC designed the research; JSCW, WKC, BF-LL and KK-LC performed the research; JSCW, WKC, BF-LL, C-PP and KK-LC analysed the data; JSCW, WKC, C-PP and KK-LC wrote the paper; and WKC, C-PP and KK-LC supervised the project. All authors have reviewed and approved the final version of the manuscript.
Funding This work was supported by The Chinese University of Hong Kong Direct Grant 4054115 and 4054194.
Competing interest None declared.
Patient consent Obtained
Ethics approval The study was approved by the Clinical Research Ethics Committee at The Chinese University of Hong Kong (Biological changes in Thyroid associated orbitopathy (TAO)/Graves' Ophthalmopathy KC/KE 10-0218/ER-3 CRE Ref. No 2010.594).
Provenance and peer review Not commissioned; externally peer reviewed.
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