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Histopathologic and immunohistochemical findings in gelatinous drop-like corneal dystrophy
S Akiya1, H Furukawa, H Sakamoto
1Department of Ophthalmology, University of Occupational and Environmental Health, Kitakyushu, Japan.
Insights
Gelatinous drop-like corneal dystrophy involves amyloid deposits. The study found corneal epithelial cells may produce a precursor of amyloid protein AA-3, suggesting a novel insight into this rare eye condition.
Area of Science:
- Ophthalmology
- Histopathology
- Biochemistry
Background:
- Gelatinous drop-like corneal dystrophy (GDLD) is a rare form of amyloidosis affecting the cornea.
- Amyloid deposits in GDLD have been characterized using histochemical and immunohistochemical methods.
Purpose of the Study:
- To investigate the specific type of amyloid protein involved in GDLD.
- To determine the cellular origin of amyloid precursors in affected corneal tissue.
Main Methods:
- Histochemical staining with Congo red dye.
- Immunohistochemical analysis using antibodies against amyloid protein AA and AA-3.
- Examination of corneal tissue from a patient with GDLD.
Main Results:
- Congo red staining was resistant to potassium permanganate pretreatment.
- Amyloid deposits within the cornea showed minimal reactivity with antibodies to amyloid protein AA and AA-3.
- Corneal epithelial cells exhibited distinct reactivity with antibodies to amyloid protein AA and AA-3.
Conclusions:
- The amyloid deposits in GDLD may not be primarily composed of classic amyloid protein AA.
- Corneal epithelial cells in GDLD patients might synthesize amyloid precursors related to protein AA-3.
- This finding suggests a potential new mechanism in the pathogenesis of gelatinous drop-like corneal dystrophy.
Abstract:
A cornea with gelatinous drop-like corneal dystrophy was examined by histochemical and immunohistochemical techniques. Pretreatment of the sections with potassium permanganate did not decrease the staining with Congo red dye. Immunohistochemically, amyloid deposits in the cornea with this disease almost did not stain with antibodies to amyloid protein AA and AA-3. However, the corneal epithelium reacted distinctly with antibodies to amyloid protein AA and AA-3. Cross-reactivity with antibodies to protein AA and serum precursor of protein AA has been reported and protein AA-3 is the synthesized peptide corresponding to the amino acid sequence 37-47 of the human amyloid protein AA molecule. The present study suggests at least that corneal epithelial cells with gelatinous drop-like corneal dystrophy may produce a precursor of amyloid related to protein AA-3.