Document Detail

Expression of degradative enzymes and protease inhibitors in corneas with keratoconus.
MedLine Citation:
PMID:  9620070     Owner:  NLM     Status:  MEDLINE    
PURPOSE: Keratoconus is characterized by thinning and scarring of the central region of the cornea. Previous research showed that, in corneas obtained from patients with keratoconus, lysosomal enzyme activities are elevated, whereas levels of protease inhibitors such as alpha1-proteinase inhibitor are reduced. This study was undertaken to examine further the expression of a spectrum of proteolytic enzymes and protease inhibitors. METHODS: Corneal buttons were collected from patients with keratoconus, healthy subjects, and patients with other corneal diseases. Immunohistochemical staining was performed on paraffin sections. Enzymatic assays and western blot analysis were carried out for cathepsins B and G. In addition, an in situ zymography procedure was used to examine the gelatin- and casein-digesting activities in corneas with keratoconus. RESULTS: An enhanced staining was found with antibodies to cathepsins B and G. Enzymatic assays and western blotting confirmed that the levels of these two enzymes were elevated in corneas with keratoconus. No alteration was noted with any of the matrix metalloproteinase (MMP) family members and other enzymes and inhibitors examined, although in situ zymography did indicate an increase in net gelatin- and casein-digesting activities in corneas with keratoconus. These activities were mostly abolished by inhibitors for serine and cysteine proteinases, but not by those for MMPs and aspartic proteinases. CONCLUSIONS: Levels of cathepsins B and G are increased in corneas with keratoconus. These enzymes may contribute to the heightened in situ gelatin- and casein-digesting activities, leading to abnormalities in keratoconus.
L Zhou; S Sawaguchi; S S Twining; J Sugar; R S Feder; B Y Yue
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Investigative ophthalmology & visual science     Volume:  39     ISSN:  0146-0404     ISO Abbreviation:  Invest. Ophthalmol. Vis. Sci.     Publication Date:  1998 Jun 
Date Detail:
Created Date:  1998-06-11     Completed Date:  1998-06-11     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7703701     Medline TA:  Invest Ophthalmol Vis Sci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1117-24     Citation Subset:  IM    
Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Aged, 80 and over
Blotting, Western
Child, Preschool
Cornea / enzymology*,  pathology
Corneal Diseases / enzymology
Endopeptidases / metabolism*
Fluorescent Antibody Technique, Indirect
Immunoenzyme Techniques
Keratoconus / enzymology*,  pathology
Middle Aged
Protease Inhibitors / metabolism*
Tissue Plasminogen Activator / metabolism*
Grant Support
Reg. No./Substance:
0/Protease Inhibitors; EC 3.4.-/Endopeptidases; EC Plasminogen Activator

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Light history and age-related changes in retinal light damage.
Next Document:  Circumcorneal annulus of collagen fibrils in the human limbus.