Changes in conjunctival clusterin expression in severe ocular surface disease.
OBJECTIVE
Clusterin is a unique gene transcript in the human ocular surface epithelia and is synthesized by and localized in mucosal epithelia in general. It is not present, however, in keratinized epithelia, such as epidermis. In severe ocular surface disease, pathologic keratinization (squamous metaplasia) of the ordinarily nonkeratinized corneal and conjunctival mucosal epithelia results in severe visual loss. In the current study, the expression of clusterin was examined in conjunctivalized corneas with severe ocular surface disease.


METHODS
We examined conjunctiva covering cornea in eight eyes with ocular surface disease (Stevens-Johnson syndrome and ocular cicatricial pemphigoid) in which pathologic keratinization was present. Normal conjunctiva from four age-matched individuals served as the control. Semiquantitative RT-PCR was used to investigate expression of the clusterin gene. Immunohistochemistry was used to study the distribution of clusterin protein.


RESULTS
The level of clusterin mRNA was significantly lower than normal in the diseased ocular surfaces. Clusterin protein was also markedly decreased in keratinized conjunctiva compared with that in normal eyes.


CONCLUSIONS
Clusterin expression is markedly reduced in the pathologic, keratinized ocular surface epithelium, suggesting its importance in maintaining the ocular surface epithelium as a nonkeratinizing epithelium.
Nakamura
Takahiro
T
Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan. tnakamur@ophth.kpu-m.ac.jp
Nishida
Kohji
K
Dota
Atsuyoshi
A
Kinoshita
Shigeru
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D051152:Clusterin; D003228:Conjunctiva / Q000378:metabolism; D003229:Conjunctival Diseases / Q000378:metabolism*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D018832:Molecular Chaperones / Q000235:genetics* / Q000378:metabolism; D010390:Pemphigoid, Benign Mucous Membrane / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013262:Stevens-Johnson Syndrome / Q000378:metabolism*
C495242:CLU protein, human; D051152:Clusterin; D006023:Glycoproteins; D018832:Molecular Chaperones; D012333:RNA, Messenger