Connective tissue growth factor in tear film of the horse: detection, identification and origin.
Abstract: Healing of corneal ulcers in horses is often associated with profound corneal stromal fibrosis and scar formation resulting in visual impairment. Connective tissue growth factor (CTGF) is a fibrogenic cytokine involved in wound healing and scarring. The purpose of this study was to determine whether CTGF was present in the tear fluid of normal horse eyes and the eyes of horses with corneal ulcers in order to evaluate the role of CTGF in corneal wound healing and corneal scar formation. Methods: Tear fluid samples were collected from 65 eyes of 44 horses; 32 samples from normal eyes, 21 samples from eyes with corneal ulceration, and 12 samples from the unaffected contralateral eyes of horses with ulcers. CTGF levels in the tears were determined by enzyme immunoassay using goat IgG against human CTGF. Antigenetic similarity of human and horse CTGF was established in a bio-equivalence assay. The identity of horse CTGF was confirmed by western blot. Lacrimal and nictitating membrane glands were investigated by immunohistochemistry in the attempt to clarify the origin of tear fluid CTGF. Results: CTGF was detected in tear film of 23 normal unaffected eyes (72%) and 8 normal contralateral eyes (67%), with the mean CTGF levels (+/- SEM) being 51.5+/-19.2 and 13.4+/-3.9 ng/ml respectively. CTGF was found in 8 eyes with corneal ulcers (38%) with the mean CTGF concentration of 26.3+/-14.8 ng/ml. Western blot identified the protein detected as CTGF. The identification of CTGF in lacrimal glands suggests a major role of these glands in the presence of CTGF in tears. Conclusions: CTGF is present in horse tear fluid and derives, at least partly, from the lacrimal gland. Equine CTGF has strong antigenic similarity with human CTGF. Corneal disease leads to a decrease of CTGF concentrations in tears. The possible role of CTGF in the healing process of ocular surface requires further investigation.
Publication Date: 2003-11-28 PubMed ID: 14648133DOI: 10.1007/s00417-003-0802-xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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This study explores the presence of Connective Tissue Growth Factor (CTGF) in the tear film of horses, focusing especially on its role in the healing of corneal ulcers and scar formation which can impair vision. The results revealed CTGF, a wound healing and fibrosis-promoting protein, is present in normal horse tear fluid and seemingly originates from the lacrimal gland – the primary source of tears.
Research Methodology
- The researchers collected tear fluid samples from a total of 65 eyes of 44 horses. The eyes were categorized based on their state: normal eyes, eyes with corneal ulcers, and the unaffected contralateral eyes (the other eye) of horses with corneal ulcers.
- A bio-equivalence assay was used to establish the antigenic similarity between human and horse CTGF.
- Enzyme immunoassay was employed using goat IgG against human CTGF to determine the CTGF levels in the tears.
- The researchers used western blot, a method that allows for the detection and identification of specific proteins, to confirm the existence of horse CTGF.
- Immunohistochemistry or IHC (a process that involves the use of antibodies to detect the presence of specific proteins in tissues) was done on the lacrimal and nictitating membrane glands to discern the origin of tear fluid CTGF.
Key Findings
- CTGF was detected in the tear film of 72% of normal eyes and 67% of unaffected contralateral eyes, the mean levels being 51.5±19.2 and 13.4±3.9 ng/ml respectively.
- In eyes with corneal ulcers, CTGF was present in 38% of cases with an average concentration of 26.3±14.8 ng/ml.
- The protein detected was confirmed to be CTGF by the western blot method.
- CTGF was identified in the lacrimal glands, suggesting these glands to be a predominant source of CTGF in tears.
Conclusions and Implications
- The presence of CTGF in horse tear fluid was confirmed and it was found to originate, at least partially, from the lacrimal glands.
- Equine CTGF showed strong antigenic similarity to human CTGF, supporting its identification.
- Corneal disease led to a decrease of CTGF concentrations in the tears, suggesting an inverse relationship between CTGF and corneal ailments.
- The role of CTGF in the ocular surface healing process requires further investigation, given these results.
Cite This Article
APA
Ollivier FJ, Brooks DE, Schultz GS, Blalock TD, Andrew SE, Komaromy AM, Cutler TJ, Lassaline ME, Kallberg ME, Van Setten GB.
(2003).
Connective tissue growth factor in tear film of the horse: detection, identification and origin.
Graefes Arch Clin Exp Ophthalmol, 242(2), 165-171.
https://doi.org/10.1007/s00417-003-0802-x Publication
Researcher Affiliations
- Departments of Large and Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32601-0126, USA.
- Departments of Large and Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32601-0126, USA. Brooksd@mail.vetmed.ufl.edu.
- Department of Obstetrics/Gynecology, Institute of Wound Healing, University of Florida, Gainesville, Florida, USA.
- Department of Obstetrics/Gynecology, Institute of Wound Healing, University of Florida, Gainesville, Florida, USA.
- Departments of Large and Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32601-0126, USA.
- Departments of Large and Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32601-0126, USA.
- Departments of Large and Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32601-0126, USA.
- Departments of Large and Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32601-0126, USA.
- Departments of Large and Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32601-0126, USA.
- St. Eriks Eyes Clinic, Karolinska Institute, Stockholm, Sweden.
MeSH Terms
- Animals
- Blotting, Western / veterinary
- Connective Tissue Growth Factor
- Corneal Ulcer / metabolism
- Corneal Ulcer / veterinary
- Down-Regulation
- Enzyme-Linked Immunosorbent Assay / veterinary
- Horse Diseases / metabolism
- Horses
- Immediate-Early Proteins / metabolism
- Immunoenzyme Techniques / veterinary
- Intercellular Signaling Peptides and Proteins / metabolism
- Lacrimal Apparatus / metabolism
- Mitogens / metabolism
- Tears / metabolism
Grant Funding
- EY05587 / NEI NIH HHS
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Citations
This article has been cited 2 times.- Hassan MDS, Razali N, Abu Bakar AS, Abu Hanipah NF, Agarwal R. Connective tissue growth factor: Role in trabecular meshwork remodeling and intraocular pressure lowering. Exp Biol Med (Maywood) 2023 Aug;248(16):1425-1436.
- Green-Church KB, Nichols KK, Kleinholz NM, Zhang L, Nichols JJ. Investigation of the human tear film proteome using multiple proteomic approaches. Mol Vis 2008 Mar 7;14:456-70.
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