Aqueous Production Research Articles

Novel therapeutic targets for reduction of intraocular pressure in primary open angle glaucoma

Glaucoma is a major cause of blindness in China and the world. Currently, all therapeutic means in treating open-angle glaucoma are limited to control the progression of optic neuropathy by lowering intraocular pressure (IOP). Clinically available medicines lower IOP by either enhancing the uveoscleral pathway or inhibiting aqueous humor production. Since the primary cause of IOP elevation in POAG is elevated outflow resistance in the trabecular outflow pathway, current medicines are not able to correct the underlying pathogenesis and pathophysiology of the disease. In this review article, we discuss a series of new therapeutic targets and therapeutic approaches that are designed to directly modify the pathological changes related to the reduction in trabecular outflow in glaucoma patients. Some of these targets and approaches may produce a significant breakthrough in the treatment of this devastating disease. (Chin J Ophthalmol, 2016, 52: 471-475).

Effects of intramuscular injection of glycopyrrolate on Schirmer tear test I results in dogs.

OBJECTIVE To determine effects of glycopyrrolate administered IM on Schirmer tear test I (STT I) measurements in dogs. DESIGN Prospective clinical study. ANIMALS 13 client- and staff-owned dogs. PROCEDURES For both eyes of each dog, STT I measurements were recorded twice 20 minutes apart (at T1 and T2) and 2 to 4 hours later (at T3). Glycopyrrolate (0.01 mg/kg [0.005 mg/lb]) was administered IM to all dogs (3 dogs received an injection of saline [0.9% NaCl] solution on an earlier occasion), and final STT I measurements were recorded 20 minutes later (at T4). Intraocular pressures, heart rate, and respiratory rate were also recorded at each time point. RESULTS Ophthalmic variables did not differ between right and left eyes. In all dogs, variables at T1, T2, or T3 (measurements before glycopyrrolate administration) did not differ; baseline values were therefore defined at T3. At T4, STT I measurements were significantly decreased (mean ± SD decrease, 67.4 ± 15.4% [mean actual decrease, 15.8 mm/min]). During the same period, mean heart rate increased by 26.5 ± 12.0% (mean actual increase, 30.2 beats/min). Glycopyrrolate had no effect on intraocular pressure or respiratory rate. In 5 dogs at 24 hours after glycopyrrolate treatment, STT I measurement in each eye had returned to baseline value. Saline solution treatment (3 dogs) had no effect on any variables. CONCLUSIONS AND CLINICAL RELEVANCE In dogs, IM injection of glycopyrrolate resulted in a clinically relevant transient decrease in aqueous tear production. Application of lacrimomimetics beginning at the time of or within 20 minutes after glycopyrrolate premedication is recommended until STT I measurements return to baseline.

Genetic association and stress mediated down-regulation in trabecular meshwork implicates MPP7 as a novel candidate gene in primary open angle glaucoma.

BackgroundGlaucoma is the largest cause of irreversible blindness affecting more than 60 million people globally. The disease is defined as a gradual loss of peripheral vision due to death of Retinal Ganglion Cells (RGC). The RGC death is largely influenced by the rate of aqueous humor production by ciliary processes and its passage through the trabecular meshwork (TM) in the anterior part of the eye. Primary open angle glaucoma (POAG), the most common subtype, is a genetically complex disease. Multiple genes and many loci have been reported to be involved in POAG but taken together they explain less than 10 % of the patients from a genetic perspective warranting more studies in different world populations. The purpose of this study was to perform genome-wide search for common variants associated with POAG in an east-Indian population.MethodsThe study recruited 746 POAG cases and 697 controls distributed into discovery and validation cohorts. In the discovery phase, genome-wide genotype data was generated on Illumina Infinium 660 W-Quad platform and the significant SNPs were genotyped using Illumina GGGT assay in the second phase. Logistic regression was used to test association in the discovery phase to adjust for population sub-structure and chi-square test was used for association analysis in validation phase. Publicly available expression dataset for trabecular meshwork was used to check for expression of the candidate gene under cyclic mechanical stress. Western blot and immunofluorescence experiments were performed in human TM cells and murine eye, respectively to check for expression of the candidate gene.ResultsMeta-analysis of discovery and validation phase data revealed the association of rs7916852 in MPP7 gene (p = 5.7x10−7) with POAG. We have shown abundant expression of MPP7 in the HTM cells. Expression analysis shows that upon cyclic mechanical stress MPP7 was significantly down-regulated in HTM (Fold change: 2.6; p = 0.018). MPP7 protein expression was also found to be enriched in the ciliary processes of the murine eye.ConclusionUsing a genome-wide approach we have identified MPP7 as a novel candidate gene for POAG with evidence of its expression in relevant ocular tissues and dysregulation under mechanical stress possibly mimicking the disease scenario.Electronic supplementary materialThe online version of this article (doi:10.1186/s12920-016-0177-6) contains supplementary material, which is available to authorized users.

Neovascular Glaucoma – A Review

Neovascular glaucoma (NVG) is a potentially blinding clinical condition, where delayed diagnosis or poor management can result in complete loss of vision. In managing NVG, it is essential to treat both the elevated intraocular pressure (IOP) and the underlying cause of disease. The objective of this review is to discuss its etiology, pathophysiology, clinical features and management. First priority in managing NVG should be to try preventing its development by appropriate treatment of the causative diseases. Since NVG is a secondary glaucoma, a thorough knowledge about the varied etiologies and meticulous methods of examination along with high index of suspicion is a must. Blindness caused due to NVG is totally preventable if diagnosis is made in early stages and such patients are aggressively treated along with frequent follow up. Detailed clinical examination including slit lamp evaluation, IOP measurement, gonioscopy, dilated retinal evaluation with 90D and 20D lenses and Fundus Fluorescein Angiography (wherever required) is a must in all cases with identifiable risk factors. In established cases of PDR, pan retinal photocoagulation (PRP) with or without intravitreal anti-VEGF is the procedure of choice to prevent NVG. Mainstay of medical treatment is to reduce aqueous production. In refractory cases requiring surgical intervention, the results have improved significantly with use of antifibrotic agents during trabeculectomy and evolution of tube shunts. The introduction of anti-VEGF agents in the management of NVG has proved to be a benchmark in both prevention and treatment of this disease. Prevention and early diagnosis is the key to reduce visual loss caused by this devastating disease. Though the treatment of NVG still remains a challenge, the advent of anti-fibrotic agents, tube shunts and anti-VEGFs has revolutionized its management and promises relatively better outcomes.

Effects of 1% Topical Brinzolamide on Intraocular Pressure in Healthy Dogs

Background: Glaucoma is one of the most common causes of blindness in dogs, and is generally characterized by death of the retinal ganglion cells associated with a rapid loss of vision. Increased intraocular pressure (IOP) occurs in patients with primary glaucoma, due to genetic abnormalities in pectinal ligaments and the trabeculae of the iridocorneal angle, producing inadequate drainage of aqueous humor. IOP is the result of the dynamic equilibrium between the production and drainage of aqueous humor. Intraocular surgery, anterior lens luxation, systemic diseases, immune-mediated, neoplastic and infectious diseases lead to the breakdown of the blood-aqueous barrier and increase the amount of protein and cells in aqueous humor, which can block this drainage pathway. Under these conditions, becomes indispensable the pharmacological control of IOP by reducing aqueous humor production. The main objective of the present study was to evaluate the effects of topical 1% brinzolamide on intraocular pressure (IOP) in twelve healthy dogs.Materials, Methods & Results: The age range of affected dogs was 1-5 years, with a mean age of 2.5 years. Twelve dogs were included in this study. All animals were healthy based on clinical, ophthalmic and hematological examinations. Selected animals were kept in a room with 500 lux luminosity, 56.8% relative humidity, 20°C temperature, exposed to 12 h of light/dark cycle, were fed twice daily and water ad libitum. All animals were adaptation to the procedures and examiners and IOP was measured by applanation tonometry at 08:00 a.m., 11:00 a.m., 02:00 p.m., 05:00 p.m., and 08:00 p.m., for 7 days and 2 days of baseline. Subsequently, one eye of each dog was randomly assigned, the eye received one drop of 1% brinzolamide at 08:30 a.m., 02:30 p.m., and 08:30 p.m. during four consecutive days and adelfo eyes received one drop of sterile saline solution and were considered control eyes. During the treatment phase and on the day after the treatment had finished, all parameters were evaluated in a blind fashion at the same pre-established time points. The value for IOP during the baseline of the treated eye were 16.77 ± 0.22 mmHg. The baseline period, values did not differ significantly between treated and control eyes. Comparison between the first day of brinzolamide-treated eyes with the average daily values of the two days of the baseline period showed that IOP decreased significantly 8.88%. IOP after four days of daily instillations of brinzolamide was able to decrease overall IOP by 1.42 mmHg (8.47%) when compared with the baseline period. Overall IOP values in the brinzolamide-treated eyes decreased 1.02 mmHg (6.24%) when compared to the control eyes. There were no statistically significant differences when compared control eye to baseline. Three times daily instillations of 1% brinzolamide in healthy dogs significantly decrease 8.47% IOP. During the post-treatment period, the average daily values of the brinzolamide-treated eyes remained 1.52 mmHg below the average daily values observed at baseline period.Discussion: The present research showed that, the average daily IOP values in the brinzolamide-treated eyes decreased 1.49 mmHg (8.88%) at the end of the first day, 1.69 mmHg (10.07%) at the end of the fourth day, and the cumulative IOP values after four days of treatment, were able to decrease by 1.42 mmHg (8.53%). Three times daily instillations of 1% brinzolamide in healthy dogs significantly decrease IOP, and therefore may be indicated to management of intraocular hypertension and glaucoma.

Haloform formation in coastal wetlands along a salinity gradient at South Carolina, United States

Environmental contextNatural haloform emissions contribute to stratospheric ozone depletion but there are major unknown or underestimated sources of these gases. This study demonstrates that soil and water at tidal wetlands are important haloform sources, and emissions peak at the forest–marsh transition zone. The low-lying forested wetlands of the south-eastern United States that are facing sea-level rise and seawater intrusion may become hotspots for haloform emission. AbstractSoil haloform emissions are sources of reactive halogens that catalytically deplete ozone in the stratosphere but there are still unknown or underestimated haloform sources. The >200000ha of low-lying tidal freshwater swamps (forests and marshes) in the south-eastern United States could be haloform (CHX3, X=Cl or Br) sources because sea-level rise and saltwater intrusion bring halides inland where they mix with terrestrial humic substances. To evaluate the spatial variation along the common forest–marsh salinity gradient (freshwater wetland, oligohaline wetland and mesohaline saltmarsh), we measured chloroform emissions from in situ chambers and from laboratory incubations of soil and water samples collected from Winyah Bay, South Carolina. The in situ and soil-core haloform emissions were both highest in the oligohaline wetland, whereas the aqueous production was highest in mesohaline saltmarsh. The predominant source shifted from sediment emission to water emission from freshwater wetland to mesohaline saltmarsh. Spreading out soil samples increased soil haloform emission, suggesting that soil pores can trap high amounts of CHCl3. Soil sterilisation did not suppress CHCl3 emission, indicating the important contribution of abiotic soil CHCl3 formation. Surface wetland water samples from eight locations along a salinity gradient with different management practices (natural v. managed) were subjected to radical-based halogenation by Fenton-like reagents. Halide availability, organic matter source, temperature and light irradiation were all found to affect the radical-based abiotic haloform formation from surface water. This study clearly indicates that soil and water from the studied coastal wetlands are both haloform sources, which however appear to have different formation mechanisms.

Effect of a Preservative-free Dorzolamide/Timolol Fixed Combination on Elevated Intraocular Pressure after Vitrectomy

Purpose: To verify the effect of preservative-free Dorzolamide/Timolol fixed combination (PFDTC) on intraocular pressure (IOP) elevation after vitrectomy. Methods: We retrospectively reviewed medical records of 33 patients who used PFDTC after pars plana vitrectomy. All patients’ visual acuity and IOP was measured and symptoms of conjunctival irritation were investigated through survey and slit lamp examination. Results: Before vitrectomy, the mean IOP was 13.6 ± 4.4 mm Hg which was elevated to 31.7 ± 5.4 mm Hg after vitrectomy (p < 0.001) and applying eyedrop lowered the mean IOP to 17.2 ± 7.0 mm Hg (p < 0.001). Regardless of tamponade material type, all elevated IOP decreased (p < 0.001) and the IOP of all 33 eyes did not rise to over 30 mm Hg again. No additional surgery for IOP control was needed during two-month follow-up period. Of the 33 patients using PFDTC, patients who felt discomfort were five (15.2%) and no patients showed side effects severe enough to stop use of eyedrop. Conclusions: PFDTC is an anti-glaucomatic agent which can reduce the IOP by inhibiting aqueous humor production. Without need for additional surgery, the eyedrop can effectively lower elevated post-vitrectomy IOP, with expectation of good patient compliance due to low risk of conjunctival irritation. J Korean Ophthalmol Soc 2016;57(9):1386-1391

Minimally invasive glaucoma surgery: current status and future prospects.

Minimally invasive glaucoma surgery aims to provide a medication-sparing, conjunctival-sparing, ab interno approach to intraocular pressure reduction for patients with mild-to-moderate glaucoma that is safer than traditional incisional glaucoma surgery. The current approaches include: increasing trabecular outflow (Trabectome, iStent, Hydrus stent, gonioscopy-assisted transluminal trabeculotomy, excimer laser trabeculotomy); suprachoroidal shunts (Cypass micro-stent); reducing aqueous production (endocyclophotocoagulation); and subconjunctival filtration (XEN gel stent). The data on each surgical procedure for each of these approaches are reviewed in this article, patient selection pearls learned to date are discussed, and expectations for the future are examined.

Ocular inflammation induces trigeminal pain, peripheral and central neuroinflammatory mechanisms

Ocular surface diseases are among the most frequent ocular pathologies, with prevalence ranging from 20% of the general population. In addition, ocular pain following corneal injury is frequently observed in clinic. The aim of the study was to characterize the peripheral and central neuroinflammatory process in the trigeminal pathways in response to cornea alteration induced by chronic topical instillations of 0.2% benzalkonium chloride (BAC) in male C57BL/6J mice. In vitro BAC induced neurotoxicity and increases neuronal (FOS, ATF3) and pro-inflammatory (IL-6) markers in primary mouse trigeminal ganglion culture. BAC-treated mice exhibited 7days after the treatment reduced aqueous tear production and increased inflammatory cell infiltration in the cornea. Hypertonic saline-evoked eye wipe behavior was enhanced in BAC-treated animals that exhibited increased FOS, ATF3 and Iba1 immunoreactivity in the trigeminal ganglion. Ocular inflammation is associated with a significant increase in IL-6 and TNF-α mRNA expression in the trigeminal ganglion. We reported a strong increase in FOS and Iba1 positive cells in particular in the sensory trigeminal complex at the ipsilateral interpolaris/caudalis (Vi/Vc) transition and Vc/upper cervical cord (Vc/C1) regions. In addition, activated microglial cells were tightly wrapped around activated FOS neurons in both regions and phosphorylated p38 mitogen-activated protein kinase was markedly enhanced specifically in microglial cells during ocular inflammation. Similar data were obtained in the facial motor nucleus. These neuroanatomical data correlated with the increase in mRNA expression of pro-inflammatory (TNF-α, IL-6, CCL2) and neuronal (FOS and ATF3) markers. Interestingly, the suppression of corneal inflammation 10days following the end of BAC treatment resulted in a marked attenuation of peripheral and central changes observed in pathological conditions.This study provides the first demonstration that corneal inflammation induces activation of neurons and microglial p38 MAPK pathway within sensory trigeminal complex. These results suggest that this altered activity in intracellular signaling caused by ocular inflammation might play a priming role in the central sensitization of ocular related brainstem circuits, which represents a significant factor in ocular pain development.

Relating sulfide mineral zonation and trace element chemistry to subsurface processes in the Reykjanes geothermal system, Iceland

The nature and distribution of sulfide minerals and their trace element chemistry in the seawater-dominated Reykjanes geothermal system was determined through the study of cuttings and core from wells that intersect different regions of the hydrothermal cell, from the near surface to depths of >3000m. The observed sulfide mineral zonation and trace element enrichment correlate well with the present-day thermal structure of the system. Isocubanite and pyrrhotite are confined to the deep, low permeability regions, whereas an assemblage of chalcopyrite and pyrite predominates in the main convective upflow path. The presence of marcasite in the uppermost regions of the system reflects weakly acidic conditions (pH<5) marginal to the upflow, where outflow and downward percolating fluids have dissolved deeply exsolved CO2. The presence of “chalcopyrite disease” in sphalerite may be an indication that the system is experiencing a heating trend, following the logic of “zone-refining” in volcanogenic massive sulfide systems. Sulfide sulfur at all analyzed depths in the Reykjanes geothermal system was derived from a mixture of basaltic and reduced seawater sources. Petrographic evidence suggests that seawater-derived hydrothermal fluids have altered primary igneous sulfides in the host rocks, a process that has been proposed as a major control of aqueous sulfide production in mid-ocean ridge environments. Calculations show that igneous sulfides in the host basalts likely account for less than 5% of the total available ore metal budget in the system, however, their contribution to fluid metal budgets is probably significant because of their relatively high solubility. The processes documented by this study are likely analogous to those operating in the feeder and deep reaction zones of mid-ocean ridge seafloor hydrothermal systems. The results show that sulfide mineral zonation and trace element chemistry vary as a function of physicochemical parameters that are relevant to the characterization and exploration of geothermal energy resources.

Digoxin derivatives with selectivity for the α2β3 isoform of Na,K-ATPase potently reduce intraocular pressure

The ciliary epithelium in the eye consists of pigmented epithelial cells that express the α1β1 isoform of Na,K-ATPase and nonpigmented epithelial cells that express mainly the α2β3 isoform. In principle, a Na,K-ATPase inhibitor with selectivity for α2β3 that penetrates the cornea could effectively reduce intraocular pressure, with minimal systemic or local toxicity. We have recently synthesized perhydro-1,4-oxazepine derivatives of digoxin by NaIO4 oxidation of the third digitoxose and reductive amination with various R-NH2 substituents and identified derivatives with significant selectivity for human α2β1 over α1β1 (up to 7.5-fold). When applied topically, the most α2-selective derivatives effectively prevented or reversed pharmacologically raised intraocular pressure in rabbits. A recent structure of Na,K-ATPase, with bound digoxin, shows the third digitoxose approaching one residue in the β1 subunit, Gln84, suggesting a role for β in digoxin binding. Gln84 in β1 is replaced by Val88 in β3. Assuming that alkyl substituents might interact with β3Val88, we synthesized perhydro-1,4-oxazepine derivatives of digoxin with diverse alkyl substituents. The methylcyclopropyl and cyclobutyl derivatives are strongly selective for α2β3 over α1β1 (22-33-fold respectively), as determined either with purified human isoform proteins or intact bovine nonpigmented epithelium cells. When applied topically on rabbit eyes, these derivatives potently reduce both pharmacologically raised and basal intraocular pressure. The cyclobutyl derivative is more efficient than Latanoprost, the most widely used glaucoma drug. Thus, the conclusion is that α2β3-selective digoxin derivatives effectively penetrate the cornea and inhibit the Na,K-ATPase, hence reducing aqueous humor production. The new digoxin derivatives may have potential for glaucoma drug therapy.

Immune-mediated keratoconjunctivitis sicca in dogs: current perspectives on management.

Keratoconjunctivitis sicca (KCS) is a frequent canine ophthalmic disease, resulting from the deficiency of one or more elements in the precorneal tear film. There are different known causes of KCS in dogs, including congenital, metabolic, infectious, drug induced, neurogenic, radiation, iatrogenic, idiopathic, and immune mediated, though the last one is the most prevalent form in dogs. Initially, clinical signs of KCS include blepharospasm caused by ocular pain, mucoid to mucopurulent ocular discharge, and conjunctival hyperemia; secondary bacterial infection may also occur, with chronicity, corneal epithelial hyperplasia, pigmentation, neovascularization, and corneal ulceration. The diagnosis of KCS is based on the presence of consistent clinical signs and measurement of decreased aqueous tear production using the Schirmer tear test. Therapy is based on administering the following topical drugs: ocular lubricant, mucolytics, antibiotics, corticosteroids, pilocarpine, and immunomodulators. These last drugs (eg, cyclosporine, pimecrolimus, and tacrolimus) have immunosuppressive activity and stimulate tear production. Furthermore, the nerve growth factor is a new subject matter of the research. Although these therapies are advantageous, stimulation of natural tear production seems to provide the highest recovery in clinical signs and prevention of vision loss. The goal of the following article is to describe the recent developments about KCS in dogs emphasizing the use of new therapies.

Novel role of PELI3 as a potential biomarker for Sjogren's syndrome related dry eyes

PurposeIn Sjogren's syndrome (SS) related dry eyes (SS‐KCS), reduced aqueous tear production and tear hyperosmolarity leads to inflammatory damage to the ocular surface. microRNAs (miR) are known to alter the expression of cytokines, which plays an important role in the pathogenesis and progression of SS. The aim of this study was to isolate miRs and mRNA from conjunctival epithelial cells (CEC) of patients with primary SS (pSS) to identify potential biomarkers that might aid diagnosis and future therapy in pSS.MethodsConfirmed SS‐KCS and healthy controls were recruited to this study. mRNA isolated from conjunctival impression cytology was sent for miR and mRNA microarray. Bioinformatic analysis was performed to identify predicted targets and comparison was made with the mRNA microarray data. Validation experiments were performed in HeLa cells following transfection with selected miR mimics and predicted genes were detected using qPCR.ResultsmiR and mRNA microarray found 32 differentially expressed novel miRs and 136 differentially expressed genes in pSS patients compared to healthy controls. Following bioinformatic analysis, novel miR‐A was chosen for further analysis. miR‐A was significantly increased in pSS (p = 0.0079) and bioinformatics suggested Pellino3 (PELI3), a negative regulator of inflammatory cytokines, as a predicted target. The mRNA microarray showed a decrease in PELI3 in pSS patients compared to healthy controls (p = 0.0731). Overexpression of miR‐A mimic in HeLa cells resulted in decreased expression of PELI3, suggesting that it is a direct target for miR‐A.ConclusionsWe have identified differentially expressed miRs and gene targets from CEC in pSS. PELI3, a potential target of novel miR‐A which is over expressed in pSS, is a negative regulator of cytokines that might have biomarker and therapeutic potential for pSS related dry eyes.

Novel role of PELI3 as a potential biomarker for Sjogren's syndrome related dry eyes

PurposeIn Sjogren's syndrome (SS) related dry eyes (SS‐KCS), reduced aqueous tear production and tear hyperosmolarity leads to inflammatory damage to the ocular surface. microRNAs (miR) are known to alter the expression of cytokines, which plays an important role in the pathogenesis and progression of SS. The aim of this study was to isolate miRs and mRNA from conjunctival epithelial cells (CEC) of patients with primary SS (pSS) to identify potential biomarkers that might aid diagnosis and future therapy in pSS.MethodsConfirmed SS‐KCS and healthy controls were recruited to this study. mRNA isolated from conjunctival impression cytology was sent for miR and mRNA microarray. Bioinformatic analysis was performed to identify predicted targets and comparison was made with the mRNA microarray data. Validation experiments were performed in HeLa cells following transfection with selected miR mimics and predicted genes were detected using qPCR.ResultsmiR and mRNA microarray found 32 differentially expressed novel miRs and 136 differentially expressed genes in pSS patients compared to healthy controls. Following bioinformatic analysis, novel miR‐A was chosen for further analysis. miR‐A was significantly increased in pSS (p = 0.0079) and bioinformatics suggested Pellino3 (PELI3), a negative regulator of inflammatory cytokines, as a predicted target. The mRNA microarray showed a decrease in PELI3 in pSS patients compared to healthy controls (p = 0.0731). Overexpression of miR‐A mimic in HeLa cells resulted in decreased expression of PELI3, suggesting that it is a direct target for miR‐A.ConclusionsWe have identified differentially expressed miRs and gene targets from CEC in pSS. PELI3, a potential target of novel miR‐A which is over expressed in pSS, is a negative regulator of cytokines that might have biomarker and therapeutic potential for pSS related dry eyes.

The effects of hormone replacement therapy on dry eye syndromes evaluated by Schirmer test depend on patient age.

This study was performed to explore the effects of hormone replacement therapy (HRT) on aqueous tear production and tear quality in dry eye syndrome (DES) patients of different ages. Eighty-eight women with DES at least one year after spontaneous menopause were randomly divided into the HRT group that were treated with orally estrogen and medroxyprogesterone acetate or a control group that did not receive any treatment. The aqueous tear production and tear quality were measured by Schirmer test and tear film break up time (TBUT) before and after one month of treatment. The subjects were subdivided according to age; the HRT group was divided into groups A (age range: 44-49 years) and B (age range: 50-57 years), and the controls were divided into groups C (age range: 46-49 years) and D (age range: 50-55 years). The changes in results of Schirmer test and TBUT before and after treatment were compared within each group and were correlated with the age of the participants. After one-month follow-up, HRT use improved the Schirmer test but the effect was significant only for participants less than 50 years old. The improvement in Schirmer test result was negatively correlated with the age of the participants. The TBUT did not change significantly within each group after HRT use. HRT use may improve aqueous tear production but not the quality of tears in DES, and the effect on tear production is dependent on age.

How Blink Anomalies Can Contribute to Post-LASIK Neurotrophic Epitheliopathy

: Post-LASIK (laser in situ keratomileusis) symptoms and signs of dry eye have multiple causes. For example, tear osmolarity and the concentration of inflammatory mediators can increase because of reduced aqueous production and increased evaporative loss as a result of lower blink rates and increased interblink intervals. The tear concentration of inflammatory mediators can also increase because of surgical trauma, wound healing, comorbid systemic and ocular diseases, and the use of punctal plugs. Studies that examine only mechanical sensitivity of the cornea cannot detect changes in chemical sensitivity, which can persist longer. Symptoms may be partly attributed to sensitization of the traumatized corneal or lid wiper sensory nerves by inflammatory mediators. Increased lid wiper sensitivity could increase awareness of blinks, especially if ocular surface lubricity is reduced. Incomplete blinks have been found to represent 10 to 22% of the total number of blinks. Loss of neural stimuli and lower blink rates increase the significance of incomplete blinks that approximately double related interblink intervals and tear evaporation. The most common location of post-LASIK epitheliopathy is the inferior area of the cornea, which is overexposed by incomplete blinks. The relevance of incomplete blinking to post-LASIK epitheliopathy is supported by the relative absence of this complication in the similarly neurotrophically disadvantaged upper corneal areas for which blink rates and other tear functions usually appear to be adequate to prevent epitheliopathy, which stains. Occupational or leisure-time activities such as computer use and reading, which have been found to reduce blink rates and blink completeness, appear to be significant risk factors for symptoms and signs of dry eye. Apart from reducing symptoms and signs of dry eye, prophylactic and post-LASIK blink exercises to reduce incomplete blink rates and associated overexposure of the ocular surface may also contribute to more accurate refractive outcomes through faster wound healing.

Role of Matrix Metalloproteinases 2 and 9 in Lacrimal Gland Disease in Animal Models of Sjögren's Syndrome.

Chronic inflammation of the lacrimal gland results in changes in the composition of the extracellular matrix (ECM), which is believed to compromise tissue repair. We hypothesized that increased production/activity of matrix metalloproteinases (MMPs), especially MMP-2 and -9, in inflamed lacrimal glands modifies the ECM environment, therefore disrupting tissue repair. The lacrimal glands from female MRL/lpr and male NOD mice along with their respective control strains were harvested and divided into three pieces and processed for histology, immunohistochemistry, zymography, Western blotting, and RNA analyses. In another study, MRL/lpr mice were treated for 5 weeks with a selective MMP2/9 inhibitor peptide or a control peptide. At the end of treatment, the lacrimal glands were excised and the tissue was processed as described above. There was a 2.5- and 2.7-fold increase in MMP2 gene expression levels in MRL/lpr and NOD mice, respectively. Matrix metalloproteinase 2 and 9 enzymatic activities and protein expression levels were significantly upregulated in the lacrimal glands of MRL/lpr and NOD mice compared to controls. Treatment with the MMP2/9 inhibitor resulted in decreased activity of MMP-2 and -9 both in vitro and in vivo. Importantly, MMP2/9 inhibitor treatment of MRL/lpr mice improved aqueous tear production and resulted in reduced number and size of lymphocytic foci in diseased lacrimal glands. We conclude that MMP2/9 expression and activity are elevated in lacrimal glands of two murine models of Sjögren's syndrome, suggesting that manipulation of MMP2/9 activity might be a potential therapeutic target in chronically inflamed lacrimal glands.

Distribution of galanin receptors in the human eye

The neuropeptide galanin (GAL) is widely distributed within intrinsic and extrinsic sources supplying the eye. It is involved in regulation of the vascular tone, thus important for ocular homeostasis. Since the presence/distribution of its receptors is unknown, we here screen for the presence of the various GAL receptors in the human eye. Meeting the Helsinki-Declaration, human eyes (n = 6; 45–83 years of age, of both sex, post mortem time 10–19 h) were obtained from the cornea bank and prepared for immunohistochemistry against GAL receptors 1–3 (GALR1–GALR3). Over-expressing cell assays served as positive controls and confocal laser-scanning microscopy was used for documentation. Cell assays reliably detected immunoreactivity for GALR1-3 and cross-reactions between antibodies used were not observed. In the cornea, GALR1-3 were detected in basal layers of the epithelium, stroma, endothelium, as well as in adjacent conjunctiva. In the iris, GALR1-3 were detected in iris sphincter and dilator, while iris vessels displayed immunoreactivity for GALR1 and GALR3. In the ciliary body, GALR1 was exclusively found in the non-pigmented epithelium while GALR3 was detected in the ciliary muscle and vessels. In the retina, GALR1 was present in fibers of the IPL, OPL, NFL, many cells of the INL and few cells of the ONL. GALR2 and GALR3 were present in few neurons of the INL, while GALR2 was also found surrounding retinal vessels. RPE displayed weak immunoreactivity for GALR2 but intense immunoreactivity for GALR3. In the choroid, GALR1-3 were detectable in intrinsic choroidal neurons and nerve fibers of the choroidal stroma, and all three receptors were detected surrounding choroidal blood vessels, while the choriocapillaris was immunoreactive for GALR3 only. This is the first report of the various GALRs in the human eye. While the presence of GALRs in cornea and conjunctiva might be relevant for wound healing or inflammatory processes, the detection in iris vessels (GALR1, 2) and choroidal vessels (GALR1-3) highlights the role of GAL in vessel dynamics. Presence of GALR1 in ciliary body epithelium and GALR3 in ciliary vessels indicates involvement in aqueous humor production, whereas retinal GALR distribution might contribute to signal transduction.

Effect of oral omega-3 Fatty Acid supplementation on contrast sensitivity in patients with moderate meibomian gland dysfunction: a prospective placebo-controlled study.

To evaluate the effect of oral supplementation with omega-3 (ω-3) fatty acids (FAs) in improving contrast sensitivity (CS) of patients with moderate meibomian gland dysfunction (MGD). In this prospective study, 60 patients with moderate MGD were allocated alternately to treatment and control groups. Both groups received warm compresses, lid massage, and artificial tear substitutes. The treatment group also received oral supplements of 1.2 g ω-3 FAs per day. All parameters were recorded at baseline and at 12 weeks and included Ocular Surface Disease Index scores, CS testing at 3, 6, 12, and 18 cycles per degree (cpd), tear break-up time, Schirmer test I without anesthesia, corneal and conjunctival staining scores, and meibum quality and expressibility. At the end of 12 weeks, significant improvement in CS was seen in the treatment group in 7 of the 8 testing conditions (3, 6, 12, and 18 cpd photopic and 6, 12, and 18 cpd mesopic), whereas in the placebo group, significant improvement was seen only in 3 of the 8 testing conditions (3 cpd photopic, 6 and 18 cpd mesopic). Ocular Surface Disease Index, tear break-up time, ocular surface staining, and meibum quality and expressibility improved significantly in both groups, but more so in the treatment group. Schirmer scores showed no significant improvement in either group. Oral supplementation with ω-3 FAs significantly improved CS under both photopic and mesopic testing conditions in patients with moderate MGD. Tear film stability also improved significantly, whereas no effect was seen on aqueous tear production.

Human Tear Serotonin Levels Correlate with Symptoms and Signs of Dry Eye

Serotonin, a neurotransmitter known to be involved in nociceptor sensitization, is present in human tears. The purpose of this study was to correlate tear serotonin levels, as a marker of nociceptor sensitization, to facets of dry eye (DE), including symptoms and signs. Cross-sectional study. A total of 62 patients with normal eyelid and corneal anatomy were prospectively recruited from a Veterans Administration Ophthalmology Clinic over 11 months. Dry eye symptoms (Ocular Surface Disease Index [OSDI]), signs (tear break-up time [TBUT], corneal staining, and Schirmer's score), and clinical descriptors of neuropathic ocular pain (NOP) (sensitivity to light or sensitivity to wind) were assessed. For tear analysis, each patient's tears were collected after instilling 50 μl of sterile saline to the lower cul-de-sac of each eye and using capillary action microcaps to collect the ocular wash. Tear serotonin levels were measured using enzyme-linked immunosorbent assay. Correlations between tear serotonin concentrations and DE symptoms and signs. The mean age of the population was 61±14 years, and 84% (n = 52) of the patients were male. Serotonin concentrations negatively correlated with Schirmer's scores (r = -0.28; P = 0.02) but did not correlate with other DE parameters, such as OSDI scores, sensitivity to light or wind, TBUT, and staining. According to our hypothesis, we divided patients into groups based on both DE symptoms and aqueous tear production; serotonin concentrations were significantly higher in DE group 1 (OSDI ≥6 and Schirmer's <8) compared with both DE group 2 (OSDI ≥6 and Schirmer's ≥8) and controls (OSDI <6 and Schirmer's ≥8). Patients in DE group 2 more frequently reported sensitivity to light (64%) and wind (67%) compared with DE group 1 (40% and 60%, respectively) and controls (8% and 17%, respectively). Patients with DE symptoms and aqueous tear deficiency had higher tear serotonin levels compared with those with DE symptoms but normal tear production and those without DE symptoms.