Ocular symptoms of
transthyretin (TTR)-related familial amyloidotic
polyneuropathy (FAP) suggest that ciliary pigment epithelium (CPE) may synthesize TTR and its TTR may lead to
amyloid formation in addition to TTR from vessels and retinal pigment epithelium (RPE). To clarify sites of TTR synthesis in ocular tissues, we performed in situ hybridization and reverse transcription-polymerase chain reaction (RT-PCR) for qualitative detection of TTR
mRNA. In addition, we quantified levels of TTR
mRNA expression by means of real-time quantitative RT-PCR. Furthermore, although TTR is an anti-
acute phase protein in serum level, no reports on changes in TTR expression in ocular tissues during acute
inflammation exist. To investigate changes in TTR expression in ocular tissues during
inflammation, we induced
uveitis by
endotoxin challenge in rabbits and used real-time quantitative RT-PCR to examine changes in TTR
mRNA expression in ocular tissues. In situ hybridization and RT-PCR qualitatively demonstrated TTR
mRNA not only in RPE but also in CPE. Real-time quantitative RT-PCR showed that the level of TTR
mRNA expression in the CPE was about one-third of that in the RPE. TTR
mRNA expression in ocular tissues decreased as the degree of
inflammation increased. These results suggest that TTR synthesized in the CPE may lead to ocular manifestations, especially
glaucoma, in FAP. TTR
mRNA also acts as an anti-
acute phase reactant in ocular tissues.