title: Constitutively low expression of collagen XIII alpha 1 may help explain the vulnerability of the inferior rectus muscle to thyroid-associated ophthalmopathy.
abstract: Thyroid-associated ophthalmopathy (TAO) has a predilection for inferior rectus muscle that has never been explained. We conducted immunohistochemical staining for the soluble cleaved form of collagen XIII alpha 1 (COL13A1) and found constitutively low expression of COL13A1 in normal human inferior rectus muscles and moderate expression of COL13A1 in normal human medial rectus muscles. COL13A1 is known to be essential to development and maintenance of neuromuscular junctions and there is some evidence to suggest it may help support normal immune function. The combination of constitutively low expression of COL13A1, high physiological and metabolic demands, and consequentially relatively high exposure to stressors via the blood stream may help explain the particular vulnerability of inferior rectus to TAO compared to other extraocular muscles.
authors: a William Harvey Research Institute , University of London , London , UK.|b Department of Rheumatology and Inflammation Research , University of Gothenburg , Gothenburg , Sweden.
authors: Olivia Claire
authors: OC
authors: Morris
authors: c Ludwig Maximilian University Eye Clinic , Munich , Germany.
authors: Kirsten
authors: K
authors: Schebitz Walter
authors: b Department of Rheumatology and Inflammation Research , University of Gothenburg , Gothenburg , Sweden.
authors: Esbjörn
authors: E
authors: Telemo
authors: d Munich University Eye Hospital , Munich , Germany.
authors: Christoph
authors: C
authors: Hintschich
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D024181:Collagen Type XIII / Q000378:metabolism*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D049970:Graves Ophthalmopathy / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000378:metabolism*
chemical_list: D024181:Collagen Type XIII
keywords: COL13A1; collagen XIII; thyroid eye disease; thyroid-associated ophthalmopathy