IOVS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

(Investigative Ophthalmology and Visual Science. 2007;48:134-143.)
© 2007 by The Association for Research in Vision and Ophthalmology, Inc.
DOI:  10.1167/iovs.06-0339
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ayala, A.
Right arrow Articles by Twining, S. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ayala, A.
Right arrow Articles by Twining, S. S.

Corneal Activation of Prothrombin to Form Thrombin, Independent of Vascular Injury

Aidee Ayala,1 Debra J. Warejcka,1 Monica Olague-Marchan,1 and Sally S. Twining1,2

1From the Departments of Biochemistry and 2Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin.

PURPOSE. Two major functions of thrombin observed in the cornea are activation of thrombin-sensitive, proteinase-activated receptors and cleavage of fibrinogen to fibrin. The purpose of this study was to determine whether the normal human cornea itself is competent to convert prothrombin to thrombin and synthesizes the mRNA for the proteins required.

METHODS. Human corneas were processed for immunolocalization studies or separated into epithelial, stromal, and endothelial layers for proteins and RNA isolation. The protein extracts were used for Western blots, prothrombin time, and activated partial thromboplastin time assays and fibrinopeptide A generation tests. RNA was used for RT-PCR. Apoptosis of cultured human corneal cells was induced with sodium nitroprusside or camptothecin and activation of prothrombin tested.

RESULTS. Prothrombin and its mRNA were present in all three layers of human donor cornea. It was found to be associated with the cells and the extracellular matrix at similar levels across the cornea. With corneal stromal extracts, activation of either the intrinsic or extrinsic coagulation pathways resulted in thrombin activation and fibrin formation with fibrinopeptide A release. Detection of key components of the coagulation cascades confirmed noninjured human corneas contain factors required for prothrombin activation. In addition, mRNAs for representative factors and inhibitors were detected by RT-PCR and confirmed by sequencing. Apoptotic corneal stromal cells provide a surface for prothrombin activation.

CONCLUSIONS. These studies suggest that the normal avascular human cornea contains and synthesizes the components required for thrombin generation and that this process does not depend on a breech in the limbal vascular endothelium.




This article has been cited by other articles:


Home page
 IOVSHome page
R. Ponsaerts, C. D'hondt, G. Bultynck, S. P. Srinivas, J. Vereecke, and B. Himpens
The Myosin II ATPase Inhibitor Blebbistatin Prevents Thrombin-Induced Inhibition of Intercellular Calcium Wave Propagation in Corneal Endothelial Cells
Invest. Ophthalmol. Vis. Sci., November 1, 2008; 49(11): 4816 - 4827.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2007 by the Association for Research in Vision and Ophthalmology