Immunohistochemical localization of D-β-aspartic acid-containing proteins in pterygium.
Biologically uncommon D-β-aspartic acid (D-β-Asp) residues have been reported to accumulate in organs affected by age-related disorders. In the present study, we investigated the localization of D-β-Asp-containing proteins in cases of pterygium, one of the most prominent age-related ocular conditions. Immunohistochemical localization of D-β-Asp-containing proteins was investigated in surgical specimens of pterygium from 20 patients and control specimens from 10 patients. Strong immunoreactivity to D-β-Asp-containing proteins was observed in subepithelial elastotic lesions and surrounding collagenous lesions from all surgical specimens with pterygia. In contrast, no immunoreactivity to D-β-Asp-containing proteins was seen in pterygium-free specimens. D-β-Asp-containing proteins are produced in organs as they are affected by the aging process. In addition, conversion of L- to D-aspartyl residues is accelerated by ultraviolet (UV) irradiation. Since pterygia can form due to aging or UV exposure, it is reasonable to find D-β-Asp-containing proteins in specimens with pterygia. Furthermore, since D-β-Asp is a non-native amino acid, D-β-Asp-containing proteins may be recognized as allogeneic antigens. Therefore, D-β-Asp-containing proteins in pterygia may responsible for the fibrovascular changes seen in the disorder.
Department of Ophthalmology, Institute of Clinical Sciences, University of Tsukuba, Ibaraki, Japan. Electronic address: kajiyuichi@gmail.com.
Yuichi
Y
Kaji
Department of Ophthalmology, Institute of Clinical Sciences, University of Tsukuba, Ibaraki, Japan.
Tetsuro
T
Oshika
Miyata Eye Hospital, Miyazaki, Japan.
Ryouhei
R
Nejima
Miyata Eye Hospital, Miyazaki, Japan.
Saiyo
S
Mori
Miyata Eye Hospital, Miyazaki, Japan.
Kazunori
K
Miyata
Research Reactor Institute, Kyoto University, Osaka, Japan.
Noriko
N
Fujii
D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D005260:Female; D006801:Humans; D026581:Isoaspartic Acid / Q000032:analysis* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011625:Pterygium / Q000175:diagnosis / Q000378:metabolism* / Q000601:surgery
D015415:Biomarkers; D026581:Isoaspartic Acid
Pterygium; Racemization; Ultraviolet irradiation; d-Amino acids; d-β-Asp