Epithelial marker expression in Salzmann nodular degeneration shows characteristics of limbal transient amplifying cells and alludes to an involvement of the epithelium in its pathogenesis.
OBJECTIVE
To look at the epithelial nature of Salzmann nodular degeneration (SND) and its possible relation with the aetiology of the subepithelial collagen deposition.


METHODS
Histological slides of 28 patients with SND were analysed for limbal and central corneal epithelial markers. Expression pattern of these markers in the basal layer of the epithelium was analysed and compared to the expression pattern in central corneal and limbal epithelium. Statistical analysis was performed by means of analysis of variance.


RESULTS
Expression of the epithelial stem cell marker ABCG2 and p63 was low in SND. Expression of CK12, a marker for terminally differentiated epithelium, was low, as well. But, CK19 and Enolase-alpha expressions were significantly increased and resembled the expression pattern of transient amplifying cells (TAC) of the limbus.


CONCLUSIONS
The epithelium in SND shows similar characteristics as TAC of the limbus and seems to be metabolically more active than the differentiated central corneal epithelium. This could be related to the deposition of subepithelial collagen fibrils seen in SND and points out a possible involvement of the corneal epithelium in the aetiology of Salzmann nodular degeneration.
Eberwein
Philipp
P
University Eye Hospital Freiburg, Freiburg, Germany. philipp.eberwein@uniklinik-freiburg.de
Hiss
Sonja
S
Auw-Haedrich
Claudia
C
Sundmacher
Rainer
R
Hauer
Katharina
K
Boehringer
Daniel
D
Meier
Peter
P
Reinhard
Thomas
T
D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D003317:Corneal Dystrophies, Hereditary / Q000209:etiology / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D019573:Epithelium, Corneal / Q000378:metabolism*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007633:Keratins / Q000378:metabolism; D016850:Limbus Corneae / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D055815:Young Adult
C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D015415:Biomarkers; D014408:Biomarkers, Tumor; C081876:CKAP4 protein, human; D004268:DNA-Binding Proteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D025521:Tumor Suppressor Proteins; D007633:Keratins; C095157:ENO1 protein, human; D010751:Phosphopyruvate Hydratase