Marked biochemical difference in amyloid proportion between intra- and extraocular tissues in a liver-transplanted patient with hereditary ATTR amyloidosis

Abstract

In order to elucidate the pathomechanism of ocular amyloid formation in a liver-transplanted patient with hereditary ATTR amyloidosis, we investigated detailed biochemical features of ocular amyloid. The patient was a 49-year-old woman with V30M transthyretin (TTR) variant (p.TTRV50M), who underwent ophthalmectomy due to corneal rupture 10 years after liver transplantation (LT). The amyloid was selectively isolated from several portions in intra- and extraocular tissues using a laser microdissection (LMD) system and analyzed by liquid chromatography–tandem mass spectrometry to determine the composition percentage of wild-type and variant TTR in the isolated amyloid. Biochemical analysis revealed that the amyloid consisted mainly of variant TTR in intraocular tissues with a percentage > 80%. On the contrary in the extraocular muscles, wild-type TTR was the main component of the amyloid with a percentage of ∼70%. Our data indicate that intraocular amyloid formation strongly depends on locally synthesized variant TTR and the contribution of wild-type TTR to amyloid formation is quite limited.

Keywords:

• Laser microdissection
• hereditary ATTR amyloidosis
• liver transplantation
• ocular amyloidosis
• transthyretin

Declaration of interest

The authors report that they have no conflicts of interest. This study was supported by grants from the Amyloid Research Committee, Intractable Disease Division, Ministry of Health, Labor and Welfare in Japan, Amyloid Research, a Grant-in-Aid for Scientific Research, Ministry of Education, Culture, Sports, Science and Technology in Japan (26670152 to K. H. and M. Y.), and a grant from the Hokuto Foundation for Bioscience (T. Y. and M. Y.).

Supplementary material available online