Histiocytic chorioretinitis in a dog.

A 3-year-old castrated male mixed-breed dog presented with an acute bullous retinal detachment and thickened choroid of the right eye. Subretinal cytology revealed an atypical cell proliferation suggestive of neoplasia. The eye was enucleated, and the original diagnosis was a histologically benign choroidal melanocytic tumor. Further diagnostics revealed no other systemic abnormalities other than a nonhealing shoulder wound. Six months later, the left eye developed a bullous retinal detachment. This eye responded well to systemic steroids and the dog regained vision within a few weeks of initiating therapy. Results of immunohistochemistry with Melan-A and CD204 of the previously enucleated right eye caused a revision of the histologic diagnosis from melanocytic tumor to histiocytic chorioretinitis. This case highlights the subtle and sometimes confusing distinction between neoplastic and inflammatory processes on both cytology and histopathology.

Effect of bone marrow-derived mesenchymal stem cells and stem cell supernatant on equine corneal wound healing in vitro.

BACKGROUND: We aimed to determine and compare the in vitro effects of autologous bone marrow-derived mesenchymal stem cells (BM-MSCs) and mesenchymal stem cell supernatant (MSC-Sp) on the wound healing capacity of equine corneal fibroblasts using a scratch assay. METHODS: Bone marrow aspirates and eyes were collected from normal, euthanized horses with subsequent isolation and culture of BM-MSCs and corneal stromal cells. Corneal stromal cells were culture-expanded in the culture well of transwell plates and then treated with an autologous BM-MSC suspension (dose: 2.5 × 105/100 µL media with the BM-MSCs contained within the insert well), MSC-Sp solution, or naive culture media (control) for 72 h. A linear defect in confluent cell cultures was created (i.e., corneal scratch assay) to assess the cellular closure ("healing") over time. Three representative areas of the scratch in each culture were photographed at each time point and the scratch area was quantitated using image analysis software (ImageJ). Media from the scratches were analyzed for various growth factors using human enzyme-linked immunosorbent assay (ELISA) kits that crossreact with the horse. RESULTS: There was a significant percentage decrease in the scratch area remaining in the BM-MSC and MSC-Sp groups compared to the control group. There was also a significant percentage decrease in the scratch area remaining in the BM-MSC group compared to the MSC-Sp group at 36 h post-scratch and all time points thereafter. The concentration of transforming growth factor (TGF)-ß1 in the media was significantly higher in the BM-MSC group compared to the control group. CONCLUSIONS: The significant decrease in scratch area in equine corneal fibroblast cultures treated with autologous BM-MSCs compared to MSC-Sp or control treatments suggests that BM-MSCs may substantially improve corneal wound healing in horses. MSC-Sp may also improve corneal wound healing given the significant decrease in scratch area compared to control treatments, and would be an immediately available and cost-effective treatment option.

Impact of fungal species cultured on outcome in horses with fungal keratitis.

PURPOSE: To determine the significance of Aspergillus and Fusarium spp., as identified by culture, on clinical outcome in equine keratomycosis. METHODS: Retrospective analysis of 66 horses (66 eyes) evaluated at the NCSU-VH diagnosed with keratomycosis from which Aspergillus or Fusarium spp. were cultured. Horses were classified into those who improved with medical management alone or those who required surgical intervention to improve. Horses who underwent surgery were divided into globe-sparing procedures or enucleation. Effects of bacterial co-infection, previous topical steroid or antifungal use, and time of year on fungal genus and outcome were evaluated. RESULTS: Aspergillus spp. was cultured from 41 eyes (63%), while 24 eyes (37%) cultured Fusarium spp. One horse cultured both species and was not included in further evaluation. From the horses that cultured Aspergillus spp., 28 eyes (68%) required surgical intervention to control the infection: 21 (75%) of these eyes maintained globe integrity, while 7 eyes (25%) were enucleated. Of those horses with Fusarium spp., 14 eyes (58%) required surgical intervention: 11 (79%) of these eyes maintained globe integrity, while 3 eyes (21%) were enucleated. Genus of fungus cultured was not significantly associated with the need for surgical intervention nor was it significantly associated with the necessity of globe-sparing surgery versus enucleation. Additionally, bacterial co-infection, previous steroidal or antifungal use, and time of year did not affect outcome or type of fungal species cultured. CONCLUSION: Equine keratomycosis from Fusarium spp. compared to keratomycosis from Aspergillus spp. is not associated with a different clinical outcome.