Canine pre-iridal fibrovascular membranes: morphologic and immunohistochemical investigations.
OBJECTIVE
Pathologic intraocular neovascularization is a key component of many canine ophthalmic diseases such as uveitis, retinal detachment, intraocular neoplasms, and corneal perforation. The purpose of this study was to evaluate the structure of pre-iridal fibrovascular membranes (PIFMs) associated with several different disease processes and to identify specific factors associated with their development in the canine eye.


METHODS
This study examined 36 enucleated canine eyes with the diagnosis of PIFM and one of the following: lens-induced uveitis, retinal detachment, iridociliary adenoma, corneal perforation, severe hyphema, or vitreal gliovascular membranes (canine ocular gliovascular syndrome, COGS). Three histologic stains and six immunohistochemical stains were performed in all 36 PIFM eyes and four histologically normal eyes, including: hematoxylin and eosin, alcian blue periodic acid schiff (PAS), Masson's trichrome, platelet endothelial cell adhesion molecule-1 (CD31), smooth muscle actin, vimentin, laminin, vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2).


RESULTS
Pre-iridal fibrovascular membrane extracellular matrix staining was consistent with collagen and mucins in all cases and positive for laminin in most cases. All PIFMs contained CD31-positive vessels and predominantly lymphoplasmacytic inflammation. Both PIFM vessels and spindle cells were positive for laminin, vimentin, smooth muscle actin, VEGF, and COX-2. Secondary intraocular pathology and immunohistochemical staining of other intraocular structures are also reported.


CONCLUSIONS
Pre-iridal fibrovascular membrane morphology and immunohistochemical characteristics were similar across six canine disease processes, suggesting analogous pathophysiologic mechanisms. COX-2 and VEGF were identified using immunohistochemistry and may play a role in PIFM development.
Resident in Comparative Ophthalmology, University of Illinois, College of Veterinary Medicine, Small Animal Clinic, 1008 W. Hazelwood Drive, Urbana, IL 61802, USA. Zarfoss@illinois.edu
Mitzi K
MK
Zarfoss
Carrie B
CB
Breaux
Herbert E
HE
Whiteley
Ralph E
RE
Hamor
Jodi A
JA
Flaws
Philippe
P
Labelle
Richard R
RR
Dubielzig
D000236:Adenoma / Q000473:pathology / Q000662:veterinary; D000818:Animals; D004396:Coloring Agents; D051546:Cyclooxygenase 2 / Q000032:analysis; D004283:Dog Diseases / Q000276:immunology / Q000473:pathology*; D004285:Dogs / Q000033:anatomy & histology / Q000276:immunology; D007498:Iris / Q000033:anatomy & histology* / Q000098:blood supply / Q000737:chemistry / Q000276:immunology; D015811:Iris Neoplasms / Q000473:pathology / Q000662:veterinary; D009389:Neovascularization, Pathologic / Q000276:immunology / Q000473:pathology; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D012163:Retinal Detachment / Q000473:pathology / Q000662:veterinary; D014605:Uveitis / Q000473:pathology / Q000662:veterinary; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis
D004396:Coloring Agents; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D042461:Vascular Endothelial Growth Factor A; D051546:Cyclooxygenase 2