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Marcelo Sobrinho, Sultan Aldrees, Pablo Zoroquiain, Patrick Logan, Ana Beatriz Toledo Dias, Miguel N Burnier; Immunohistochemical profile of keratoconic corneas. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4897.
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© ARVO (1962-2015); The Authors (2016-present)
Keratoconus (Kc) is a rare bilateral non-inflammatory progressive corneal dystrophy, the etiology of which remains unclear. Comparisons between components of normal (NC) and keratoconic corneas will provide insight into the pathophysiology of this sight-threatening condition. The purpose of the present study is to compare the presence of fibronectin (Fn), laminin (Lm) and collagen 1 a1 (Col1a1) in NC and Kc corneas.
Seventeen Kc corneas were stained for Fn, Lm and Col1a1 using an automated immunostaining protocol. Expression was analyzed in each corneal layer: epithelium (Ep), basement membrane (BM), Bowman’s layer (BL), anterior, middle and posterior stroma (AS, MS, PS), Descemet’s membrane (DM), and endothelium (En).We also divided each cornea into thirds: central (the area in front of the pupil) and both peripheral areas. For each protein, we classified the staining with respect to staining intensity (0, absent; 1, mild; or 2, intense) and extension (0 = no staining; 1 = <50%; 2 = >50%). Intensity and extension were summed to create an immunoreactive score (IRS). Differences between NCs and Kc corneas were assessed by Mann-Whitney U or Wilcoxen test, as appropriate.
Fn and Col 1A1 IRS scores were significantly higher in AS, MS, and PS, both centrally and peripherally, in Kc corneas relative to NCs (P<0.05).In the periphery, Lm and Fn were significantly lower in Kc corneas in DM, and Lm was lower in the En compared to NCs (P<0.05).No significant differences in IRS for all markers or other layers were identified.
Our results show that there are significant differences in the immunohistochemical profile of some corneal layers in NCs compared to Kc corneas. Since Fn and Lm have important adhesion functions, and the function of Col 1A1 is to give tissue tensile strength, it is possible that these differences play a role in the keratoconus progression.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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