Effects of three blood derived products on equine corneal cells, an in vitro study.

BACKGROUND: Despite advances in therapy of corneal ulcerative diseases in horses, a vast number of cases require surgical intervention, due to poor response to treatment. Topical application of serum has been used for many years, based on its anticollagenolytic properties and the presence of growth factors promoting corneal wound healing. However, although other blood derived products i.e. platelet rich plasma (PRP), plasma rich in growth factors (PRGF) have been widely used in equine orthopaedics and in human ophthalmology, no reports of the effects of these blood derived products exist in equine ophthalmology. OBJECTIVES: To determine in vitro effects of PRGF and PRP on equine corneal cells compared with serum. STUDY DESIGN: Prospective controlled cohort study. METHODS: Blood from 35 healthy horses was used to produce serum, PRGF (Endoret® ), and PRP (E-PET™). Limbal- and stromal cells were isolated from healthy corneas of six horses and treated with 20% serum, 20% PRGF or 20% PRP. Proliferation rates and migration capacity were analysed in single cell cultures as well as co-culture systems. RESULTS: Cell proliferation increased with PRP treatment, remained constant in PRGF treated cells, and declined upon serum treatment over a period of 48 h. Migration capacity was significantly enhanced with PRP treatment, compared with PRGF treatment. Intact leucocytes, mainly eosinophils, were only detected in PRP. MAIN LIMITATIONS: Due to the study design use of autologous blood products on corneal cells was not possible. CONCLUSIONS: The results demonstrate beneficial effects of PRP on proliferation as well as migration capacity of equine corneal cells in vitro. In vivo studies are warranted to determine further beneficial effects of PRP in horses with corneal ulcers.

Keratoconjunctivitis in a group of Icelandic horses with suspected γ-herpesvirus involvement.

REASONS FOR PERFORMING STUDY: The role of equid γ-herpesviruses on ocular surface diseases has been disputed, because the diagnosis is usually based on clinical symptoms and detection of viral DNA from samples obtained from live animals. OBJECTIVES: To describe the clinical course, results of polymerase chain reaction (PCR) analysis, in situ hybridisation, cell culture and pathohistological findings of select cases in a presumed outbreak of herpesvirus infection in a group of 15 Icelandic horses. STUDY DESIGN: Case series. METHODS: Pooled ocular and nasal swabs and peripheral blood mononuclear cells of horses diagnosed clinically with herpesvirus-associated keratoconjunctivitis were analysed for presence of equine herpesviruses (EHV)-2 and EHV-5 nucleic acid using real-time PCR. Necropsy specimens from one horse, subjected to euthanasia due to deterioration of clinical symptoms were examined histopathologically, and analysed for presence of EHV-2 and EHV-5 nucleic acid using real-time PCR. In situ hybridisation and cell culture of select samples were performed. RESULTS: All horses with symptoms of severe keratoconjunctivitis were positive for presence of either EHV-2 and/or EHV-5 nucleic acid using real-time PCR. Assessment of necropsy specimens of the most severely affected case, revealed presence of EHV-2 and/or EHV-5 nucleic acid in several ocular and extraocular anatomical locations. The remaining horses responded favourably to symptomatic treatment. CONCLUSIONS: This case series illustrates a severe outbreak of keratoconjunctivitis in a group of Icelandic horses, with suspected γ-herpesvirus involvement. For the first time equid γ-herpesviruses were detected in intraocular anatomical locations.

Introduction of the use of thermography and thermometry in the diagnosis of uveitis in horses: a pilot project.

AIMS AND OBJECTIVES: To date assessment of changes in ocular temperature, as a hallmark of uveitis in horses has not been determined. Therefore the aim of the current study was to determine whether ocular temperature is increased in acute uveitic eyes compared with non-uveitic eyes, and to compare an affordable thermometry device with a thermography device. MATERIAL AND METHODS: Ocular temperatures of both eyes of five horses with acute unilateral uveitis and 10 normal horses were measured using thermometry and thermography. Presence and absence of acute uveitis were diagnosed through a complete ophthalmological examination. Ambient temperature and core body temperature were also recorded. RESULTS: The difference in temperatures between uveitic eyes and non-uveitic eyes was marked but not statistically significant (mean thermography temperature 34.0°C sd±1.6°C and 32.7°C sd±2.4°C, respectively v mean thermometry temperature 34.0°C sd±1.9°C and 31.6°C sd±3.1°C, respectively). No influence of core body temperature on either method was detected. Thermography was less influenced by ambient temperature than was thermometry. CONCLUSION: In conclusion uveitic eyes are not significantly warmer than non-uveitic eyes. Despite the lack of significance, a tendency towards increased ocular temperature in uveitic eyes, compared with non-uveitic eyes was noted. Therefore more research on this topic is warranted.

Prevalence of linear keratopathy in a herd of Lipizzaners over an 18-month period.

The prevalence of linear keratopathy with progressing age in a closed population of a single horse breed is reported. All Lipizzaners in three federal states in Austria underwent complete ophthalmic examination four times over a period of 18 months, with six-month intervals. Findings consistent with linear keratopathy were recorded, and associated with factors such as sex, location, boarding system and level of performance throughout the study period. Logistic regression was applied to determine the influence of age on ophthalmic findings. On the first, second, third and fourth examinations, 0.8 per cent, 3.1 per cent, 4.4 per cent and 4.8 per cent (of 266, 261, 249 and 230 horses, respectively) of the study population, were diagnosed with linear keratopathy. This finding was consistently identified in the same horses, and once identified, no further progression was noted. Horses with this finding had no history of previous ocular problems or concurrent ocular abnormalities. Statistical analysis did not reveal any influence of sex, location, boarding, or level of performance; however the prevalence of linear keratopathy was found to increase with progressive age (P<0.5). The results of this study indicate that linear keratopathy was not congenital and was non-progressive in the Lipizzaner over a period of 18 months.