Immunohistochemical localisation of D-beta-aspartic acid in pingueculae.
BACKGROUND
D-beta-aspartic acid residues, which are biologically uncommon, have been reported to accumulate in various proteins of the living body with age. In the present study, D-beta-aspartic acid-containing proteins were found to be localised in pingueculae, which represent one of the most prominent age-related ocular changes.


METHODS
Surgical specimens of conjunctivae with or without pingueculae were obtained from eight patients. Immunohistochemical localisation of D-beta-aspartic acid-containing proteins was performed using a polyclonal antibody against D-beta-aspartic acid-containing peptides.


RESULTS
Strong immunoreactivity to D-beta-aspartic acid-containing peptides was detected in the subepithelial amorphous materials of all surgical specimens with pingueculae. In contrast, no immunoreactivity to D-beta-aspartic acid-containing peptides was detected in the specimens without pingueculae.


CONCLUSIONS
Pingueculae are thought to be aggregates of proteins that contain D-beta-aspartic acid residues. It is known that the conversion of L- to D-aspartyl residues is accelerated by ultraviolet irradiation. In addition, D-beta-aspartic acid-containing proteins, in general, tend to aggregate with each other and accumulate in the tissues. These facts indicate that ultraviolet irradiation-induced racemisation of aspartic acid is closely related to the development of pingueculae.
Kaji
Y
Y
Department of Ophthalmology, Tsukuba University Institute of Clinical Medicine, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8565, Japan. sanken-tky@umin.ac.jp
Oshika
T
T
Okamoto
F
F
Fujii
N
N
D003229:Conjunctival Diseases / Q000378:metabolism* / Q000473:pathology; D003316:Corneal Diseases / Q000378:metabolism* / Q000473:pathology; D026603:D-Aspartic Acid / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D026581:Isoaspartic Acid / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D014466:Ultraviolet Rays / Q000009:adverse effects
D026581:Isoaspartic Acid; D026603:D-Aspartic Acid