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Background: This study was conducted to evaluate whether polyunsaturated fatty acids (PUFA) such as γ-linolenic acid (GLA) and eicosapentaenoic acid (EPA), as found in the diet, may affect the lipid composition of conjunctival epithelium and whether these modifications affect prostaglandin (PG) production after inflammatory stimulation., Methods: Chang and IOBA-NHC conjunctival human cells were treated with GLA and/or EPA at 5, 10, 20, 30, 40, or 50 μg/ml for 72 h and then were stimulated with interferon-gamma (IFN-γ) for 48 h. Changes in the composition of neutral lipids and phospholipids were monitored by gas chromatography. PGE1 and PGE2 levels were measured by enzyme immunoassay., Results: PUFA supplementations in the culture medium induced incorporation of these fatty acids and of their metabolites in neutral lipids and phospholipids of the conjunctival cells. The fatty acid composition of neutral lipids and phospholipids was not affected by stimulation with IFN-γ. The production of PGE1 and PGE2 was affected by GLA supplementation whereas it was not modified by EPA supplementation. A combined supplementation of EPA and GLA did not change the production of PGE1 but decreased the production of PGE2., Conclusions: These results suggest that modulation of fatty acid composition and PG production by PUFA supplementation is possible in the conjunctival epithelium, which is an important site of inflammation in dry eye syndrome.

Purpose: Epidemiological studies suggest that dietary n-3 polyunsaturated fatty acids (PUFAs) may protect against dry eye. This study aimed to evaluate whether a dietary deficiency in n-3 PUFAs may increase the severity of the pathology in a scopolamine-induced model of dry eye in the rat., Methods: Lewis rats of three consecutive generations were bred under a balanced diet or a diet deprived of n-3 PUFAs. Dry eye was experimentally induced by continuous scopolamine delivery in female animals from the third generation of both groups. After 10 days of treatment, the clinical signs of ocular dryness were evaluated in vivo using fluorescein staining. MHC II and the rat mucin rMuc5AC were immunostained on ocular sphere cryosections. The transcript levels of the pro-inflammatory cytokines interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and interferon (IFN)-γ were quantified in the exorbital lacrimal glands (LG) and in the conjunctiva using reverse transcription followed by polymerase chain reaction. Lipids were extracted from the exorbital LG for fatty acid analysis of the phospholipids using gas chromatography., Results: When compared to control animals, the scopolamine treatment induced an increase in the cornea fluorescein staining score (from 0.5 ± 0.0 to 2.5 ± 1.0 arbitrary units (AU) for the balanced diet and from 1.2 ± 0.8 to 2.6 ± 0.5 AU for the n-3 PUFA-deficient diet); a decrease in rMuc5AC immunostaining in the conjunctival epithelium (-34% for the balanced diet and -23% for the n-3 PUFA-deficient diet); an increase in the LG transcript levels of TNF-α for the balanced diet and of TNF-α and IFN-γ for the deficient diet; an increase in the conjunctival transcript levels of IL-1β and IL-6 for the deficient diet; an increase in arachidonic acid (AA) and in the ∆5-desaturase index (ratio of AA to dihomo-gamma-linolenic acid) in the exorbital LG for both diets. When compared to the balanced diet, the n-3 PUFA-deficient diet induced an increase in the LG transcript levels of IL-6 for the control animals and of TNF-α for the control and dry eye animals as well as an increase in the conjunctival transcript levels of IL-6 for the dry eye animals. There was no significant diet difference in fluorescein staining, rMuc5AC, and MHC II immunostaining scores., Conclusions: Our data suggest that an n-3 PUFA deficiency does not increase the severity of dry eye in a rat model of dry eye.

Background: To evaluate the effect of a dietary combination of omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) compared to single PUFA supplementations on the outcome of a substantial elevation of intraocular pressure (IOP) in rats., Methods: Sprague Dawley rats were fed for 6 months with either a control diet, a diet enriched with omega-3 PUFAs (eicosapentaenoic acid, EPA, and docosahexaenoic acid, DHA), a diet enriched with omega-6 PUFAs (gamma-linolenic acid, GLA) or a diet enriched with both omega-3 and omega-6 PUFAs (EPA + DHA and GLA). After 3 months of feeding, elevation of IOP was induced by photocoagulation of the episcleral veins, limbus and trabecular meshwork using a 532-nm laser. IOP and scotopic electroretinograms (ERGs) were monitored after the induction of IOP elevation until the end of the nutritional supplementation. Retinal morphometry and GFAP immunohistochemistry were performed 3 months after laser photocoagulation. Retinal ganglion cells (RGCs) were quantified using retrograde labelling., Results: A significant rise in IOP was observed in the laser-treated eyes. PUFA supplementation did not influence the time course of IOP in the laser-treated eyes. Three months after laser photocoagulation, the activation of glial cells observed in the laser-treated eyes was significantly lower in animals fed with the EPA + DHA + GLA diet when compared to those fed the control diet, while single supplementations with either EPA + DHA or GLA were not effective. The same protective effect of the EPA + DHA + GLA combination was observed on retinal structures in the laser-treated eyes. However, PUFA supplementation did not influence either ERG b-wave amplitude or the RGC loss in the laser-treated eyes., Conclusions: This study demonstrates that a 6-month supplementation with a combination of omega-3 and omega-6 PUFAs is more effective than single supplementations, since the EPA + DHA + GLA dietary combination prevented retinal cell structure and decreased glial cell activation induced by the elevation of IOP in rats.

Background: This study was conducted to evaluate the efficacy of dietary n-6 and n-3 polyunsaturated fatty acids (PUFAs) in dry eye in a rat model., Methods: Female Lewis rats were fed with diets containing (1) gamma-linolenic acid (GLA), (2) eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA), or (3) GLA + EPA + DHA, for 2 months before the induction of dry eye using a continuous delivery of scopolamine and during scopolamine treatment. Two, 10 and 28 days after dry-eye induction, clinical signs of corneal dryness were evaluated in vivo using fluorescein staining. MHC II expression and mucin rMuc5AC production in the conjunctival epithelium were evaluated by immunostaining. Lipids and prostaglandins (PGs) E(1) and E(2) were analysed from the exorbital lacrimal gland (LG)., Results: Dietary PUFAs minimised the occurrence of corneal keratitis 28 days after induction of dry eye. The decrease in mucin production observed on the conjunctival epithelium was partially prevented by EPA + DHA supplementation after 2 days of scopolamine treatment, as well as by GLA and GLA + EPA + DHA diets after 10 days of treatment. The overexpression of MHC II in the conjunctival epithelium caused by dry eye induction was significantly reduced only with the GLA + EPA + DHA diet after 28 days of treatment. Dietary PUFAs were incorporated into phospholipids of the exorbital LG. Induction of dry eye was associated with a significant increase in PGE(1) and PGE(2) levels in the exorbital LG, which was inhibited by dietary EPA + DHA at 10 days (for PGE(2)) and 28 days (for PGE(1))., Conclusions: Dietary GLA, EPA and DHA significantly interfered with lipid homeostasis in the exorbital LG and partially prevented the course of dry eye. In particular, our results demonstrate the efficacy of the combination of n-6 and n-3 PUFAs.

Background: To assess the functional and anatomical outcome of primary vitrectomy without scleral buckling for rhegmatogenous retinal detachment (RRD) in pseudophakic patients and to present the learning curve for this surgery in less experienced surgeons., Methods: We reviewed the charts of pseudophakic patients treated with primary vitrectomy without scleral buckling for a rhegmatogenous retinal detachment with PVR

Background: The aim of this study was to set up an animal model of dry eye showing disturbance in several components of the lacrimal functional unit, and to describe the time course of the appearance of clinical signs and inflammatory markers., Methods: Dry eye was induced in 6-week-old female Lewis rats by a systemic and continuous delivery of scopolamine via osmotic pumps implanted subcutaneously. We first determined the appropriate dose of scopolamine (6, 12.5, or 25 mg/day) for 28 days. In a second set of experiments, we determined markers after 1, 2, 3, 7, 10, 17, or 28 days of a 12.5-mg/day dose. Clinical signs of corneal dryness were evaluated in vivo using fluorescein staining. MHC II expression and mucin Muc5AC production were detected on the conjunctival epithelium using immunostaining. The level of IL-1beta, IL-6, TNF-alpha, and IFN-gamma mRNA was evaluated by real-time polymerase chain reaction in conjunctiva and exorbital lacrimal gland (LG). Lipids were extracted from the exorbital LG for fatty acid analysis., Results: Daily scopolamine doses of 12.5 mg and 25 mg applied for a 28-day period induced keratitis, a decrease in Muc5AC immunostaining density in the conjunctival epithelium, and modifications in the fatty acid composition of the exorbital LG. Animals treated with a 12.5-mg/day dose of scopolamine exhibited an increase in corneal fluorescein staining after 2, 10, and 28 days. All animals exhibited unilateral or bilateral keratitis after 17 days. In the conjunctival epithelium, a significant decrease in Muc5AC immunostaining density was observed at early and late time points, and MHC II expression tended to be increased after 1, 7, 10, and 28 days, without reaching statistical significance. The levels of TNF-alpha, IL-1beta and IL-6 mRNA were increased with scopolamine treatment in both conjunctiva and exorbital LG. Arachidonic acid and the Delta5 desaturase index were significantly increased in the exorbital LG of dry eye animals at each time point., Conclusions: This systemic and continuous scopolamine-induced model of dry eye in the rat may represent a helpful tool to investigate moderate dry eye, and makes a contribution in the field of dry eye study.