Corneal Epithelial Barrier Research Articles

Phenotypic characterization of the SIRC (Statens Seruminstitut Rabbit Cornea) cell line reveals a mixed epithelial and fibroblastic nature

The aim of the present study was to investigate, in the Statens Seruminstitut Rabbit Cornea (SIRC) cell line, the presence of epithelial and fibroblastic markers, comparing their levels with those of the human Retinal Pigmented Epithelial (ARPE-19) cell line, and the Human Keratocyte (HK) cell line, respectively. SIRC cells, often described as of epithelial origin, are used as a corneal epithelial barrier model to study the permeability of ophthalmic drugs. However, they show a morphology that is more consistent with a fibroblastic cell phenotype, similar to corneal keratocytes. Our comparative analyses of cell type specific markers demonstrated that SIRC do not express cytokeratins 19 and 16 (typical of ARPE-19) and cytokeratin 9 (typical of HK); they do express cytokeratins 3 and 18 common to all three cell lines, and cytokeratin 12 typical of ARPE-19. Tight junction proteins were absent in HK, and lower in SIRC than in ARPE-19. All cell lines expressed the markers lumican and vimentin, with SIRC expressing intermediate levels between HK and ARPE-19; alpha-SMA was highly expressed in all lines. These markers, considered typical of fibroblasts, can be, however, expressed by epithelial cells during wound healing. These results might suggest that long-term in vitro cultivation of cell lines leads to a derangement of their specific phenotype, most likely due to genetic and epigenetic factors. This could be the reason why SIRC cells came to exhibit a hybrid nature between epithelial and fibroblastic cells.

Topical Application of Mizoribine Suppresses CD4+ T-cell-Mediated Pathogenesis in Murine Dry Eye.

We investigate the effect of topical application of mizoribine (MZR) eye drops on CD4+ T-cell-mediated immunity and epithelial damage in ocular surface of dry eye disease (DED). Topical application of MZR or vehicle eye drops was performed in mice subjected to desiccating stress (DS). The phenol red cotton test was used to measure tear production, and Oregon-green-dextran (OGD) staining was performed to assess corneal epithelial barrier function. PAS staining was used to quantify conjunctival goblet cells. Immunofluorescent staining and quantitative (q) RT-PCR were used to assess the expression of matrix metalloproteinase (MMP)-9 in corneal epithelium. qRT-PCR and ELISA were used to assess the production of TNF-α and IL-1β in conjunctiva. Apoptosis in ocular surface was assessed by TUNEL and activation of caspase-8. CD4+ T-cell-mediated immunity was evaluated by CD4 immunohistochemistry and production of T helper cytokines, including IFN-γ, IL-13, and IL-17A in conjunctiva. Compared to vehicle control mice, topical MZR-treated mice showed increased tear production, decreased goblet cell loss, and improved corneal barrier function. Topical application of MZR suppressed the expression of MMP-9 in corneal epithelium and apoptosis in ocular surface, while it had no obvious effect on production of TNF-α and IL-1β in conjunctiva. Topical application of MZR decreased CD4+ T cells infiltration, with decreased production of IFN-γ and IL-17A, and increased production of IL-13 in conjunctiva. Topical application of MZR could alleviate epithelial damage and CD4+ T-cell-mediated immunity in ocular surface of DED.

Contributions of MyD88-dependent receptors and CD11c-positive cells to corneal epithelial barrier function against Pseudomonas aeruginosa

Previously we reported that corneal epithelial barrier function against Pseudomonas aeruginosa was MyD88-dependent. Here, we explored contributions of MyD88-dependent receptors using vital mouse eyes and confocal imaging. Uninjured IL-1R (−/−) or TLR4 (−/−) corneas, but not TLR2 (−/−), TLR5 (−/−), TLR7 (−/−), or TLR9 (−/−), were more susceptible to P. aeruginosa adhesion than wild-type (3.8-fold, 3.6-fold respectively). Bacteria adherent to the corneas of IL-1R (−/−) or TLR5 (−/−) mice penetrated beyond the epithelial surface only if the cornea was superficially-injured. Bone marrow chimeras showed that bone marrow-derived cells contributed to IL-1R-dependent barrier function. In vivo, but not ex vivo, stromal CD11c+ cells responded to bacterial challenge even when corneas were uninjured. These cells extended processes toward the epithelial surface, and co-localized with adherent bacteria in superficially-injured corneas. While CD11c+ cell depletion reduced IL-6, IL-1β, CXCL1, CXCL2 and CXCL10 transcriptional responses to bacteria, and increased susceptibility to bacterial adhesion (>3-fold), the epithelium remained resistant to bacterial penetration. IL-1R (−/−) corneas also showed down-regulation of IL-6 and CXCL1 genes with and without bacterial challenge. These data show complex roles for TLR4, TLR5, IL-1R and CD11c+ cells in constitutive epithelial barrier function against P. aeruginosa, with details dependent upon in vivo conditions.

Therapeutic Effect of MK2 Inhibitor on Experimental Murine Dry Eye.

To investigate the role of mitogen-activated protein kinase-activated protein kinase-2 (MK2) in ocular surface damage of dry eye. MK2 inhibition was performed in mice subjected to desiccating stress (DS) by topical application of MK2 inhibitor (MK2i) or vehicle eye drops. The total and phosphorylated MK2 in conjunctiva were detected by Western blot. The phenol red cotton test was used to measure tear production, and Oregon green dextran staining was performed to assess corneal epithelial barrier function. PAS staining was used to quantify conjunctival goblet cells. Immunofluorescent staining and quantitative RT-PCR were used to assess the expression of matrix metalloproteinase (MMP)-3 and -9 in corneal epithelium. Apoptosis in ocular surface was assessed by TUNEL and immunofluorescent staining for activated caspase-3 and -8. Inflammation was evaluated by CD4+ T-cell infiltration and production of T helper (Th) cytokines, including IFN-γ, IL-13, and IL-17A in conjunctiva. DS promoted MK2 activation in conjunctiva. Compared with vehicle control mice, MK2i-treated mice showed increased tear production, decreased goblet cell loss, and improved corneal barrier function. Topical MK2 inhibition decreased the expression of MMP-3 and -9 in corneal epithelium, and suppressed cell apoptosis in ocular surface under DS. Topical MK2 inhibition decreased CD4+ T-cell infiltration, with decreased production of IFN-γ and IL-17A and increased production of IL-13 in conjunctiva. Topical MK2 inhibition effectively alleviated ocular surface damage via suppressing cell apoptosis and CD4+ T-cell-mediated inflammation in ocular surface of dry eye.

Transport mechanism of chitosan-N-acetylcysteine, chitosan oligosaccharides or carboxymethyl chitosan decorated coumarin-6 loaded nanostructured lipid carriers across the rabbit ocular

To facilitate the hydrophobic drugs modeled by coumarin-6 (Cou-6) acrossing the cornea to the anterior chamber of the rabbit eye, chitosan (CS) derivatives including chitosan-N-acetyl-l-cysteine (CS-NAC), chitosan oligosaccharides (COS) and carboxymethyl chitosan (CMCS) modified nanostructured lipid carriers (NLCs) were designed and characterized. We found that, with similar size distribution and positivecharges, different CS derivatives based on NLCs led to distinctive delivery performance. In vivo precorneal retention study on rabbits revealed that these CS derivatives coating exhibited a stronger resistant effect than Cou-6 eye drops and Cou-6-NLC (P<0.05), moreover, the AUC(0−∞), Cmax and MRT(0−∞) of them followed the sequence of CMCS-Cou-6-NLC<COS-Cou-6-NLC<CS-NAC-Cou-6-NLC. Confocal laser fluorescence microscopy (CLSM) for in vitro corneal penetration study showed that COS-, and CS-NAC-coated NLCs penetrated through the whole corneal epithelium barrier (about 40μm), while CMCS failed to significantly enhance the intraocular drug penetration as expected, displayed a negligible fluorescence at 30μm deep. In addition, penetration through the intact cornea was achieved and the penetration levels through the ocular tissues were increased thoroughly for the COS and CS-NAC coating ones compared with CMCS-NLC (P<0.05), and successfully reduced the conjunctival-to-corneal permeability ratio (ratio(C-S/C)) thus resulted in a higher bioavailability, which was confirmed by ex vivo fluorescence imaging on ocular tissues. In summary, CS-NAC-NLC and COS-NLC are promising ocular drug delivery systems to achieve prolonged precorneal retention, higher corneal permeability and enhanced ocular bioavailability. And comparatively speaking, CS-NAC-NLC possesses the highest potential for ocular drug delivery.

Changes in Ocular Surface Characteristics after Switching from Benzalkonium Chloride-Preserved Latanoprost to Preservative-Free Tafluprost or Benzalkonium Chloride-Preserved Tafluprost.

Purpose The aim of the present study was to examine the effects of switching from Latanoprost ophthalmic solution containing a preservative to preservative-free Tafluprost ophthalmic solution or Tafluprost containing a preservative on ocular surfaces. Materials and Methods Forty patients (40 eyes) with glaucoma (mean age: 62.0 ± 10.9 years) using Latanoprost with preservative for six months or longer were assigned either to a Tafluprost-containing-preservative group (20 eyes) or preservative-free-Tafluprost group (20 eyes). The intraocular pressure, corneal epithelial barrier function (fluorescein uptake concentration with fluorophotometer FL-500), superficial punctate keratopathy (AD classification), and tear film breakup time (TBUT) were assessed before switching and at 12 weeks after switching. Results No significant differences in intraocular pressure were noted after switching in either group. Corneal epithelial barrier function was improved significantly after switching in both the Tafluprost-containing-preservative and the preservative-free-Tafluprost groups. There were no significant differences in AD scores after switching in the Tafluprost-containing-preservative group, but significant improvements were noted in the preservative-free-Tafluprost group. No significant differences in TBUT were noted in the Tafluprost-containing-preservative or preservative-free-Tafluprost groups after switching. Conclusion After switching from preservative Latanoprost to Tafluprost containing-preservative or preservative-free Tafluprost, corneal epithelial barrier function was improved while the intraocular pressure reduction was retained.

Ocular Surface and External Filtration Surgery: Mutual Relationships.

There is a large body of evidence from clinical and experimental studies indicating that the long-term use of topical drugs may induce ocular surface changes, causing ocular discomfort, dry eye, conjunctival inflammation, subconjunctival fibrosis, corneal surface impairment, and, as a consequence of chronic ocular surface changes, the potential risk of failure for further glaucoma surgery. Subclinical inflammation has also been widely described in patients receiving antiglaucoma treatments for long periods of time, with inflammatory cell infiltration and fibroblast activation in the conjunctiva and subconjunctival space. Preservatives, especially benzalkonium chloride, which has consistently demonstrated its toxic effects in laboratory, experimental, and clinical studies, could induce or enhance such inflammatory changes, and has been recently confirmed as a direct risk factor of surgical failure. As a quaternary ammonium, this compound causes tear film instability, loss of goblet cells, conjunctival squamous metaplasia and apoptosis, disruption of the corneal epithelium barrier, corneal nerve impairment, chronic inflammation and potential damage to deeper ocular tissues. Drug-induced adverse effects are therefore far from restricted to only allergic reactions, but they are often very difficult to identify because they mostly occur in a delayed or poorly specific manner, and result from complex and multifactorial interactions between the drugs and the ocular surface. Postoperatively, the ocular surface also plays an important role, as the conjunctiva interacts with aqueous humor and subconjunctival fibrosis may block aqueous outflow and cause surgical failure. As preoperative inflammation underlies postoperative fibrosis and therefore surgical outcome, a better knowledge of ocular surface changes with appropriate evaluation and management should thus become a new paradigm in glaucoma care over the long term.

Recent studies on corneal epithelial barrier function

Corneal epithelium, the outermost layer of eyeball, is the main route for foreign materials to enter the eye. Under physiological conditions, the corneal epithelial superficial cells form a functionally selective permeability barrier. Integral corneal epithelial barrier function not only ensures the enrolling of nutrients which is required for regular metabolism, but also prevents foreign bodies, or disease-causing microorganism invasion. Recently, a large number of clinical and experimental studies have shown that abnormal corneal epithelial barrier function is the pathological basis for many ocular diseases. In addition, some study found that corneal epithelial barrier constitutes a variety of proteins involved in cell proliferation, differentiation, apoptosis, and a series of physiological and pathological processes. This paper reviewed recent studies specifically on the corneal epithelial barrier, highlights of its structure, function and influence factors. (Chin J Ophthalmol, 2016, 52: 631-635).

Epithelial cell adhesion molecule-1 (ECAM1) is required in the maintenance of corneal epithelial barrier integrity.

Corneal epithelial barrier integrity is critical in the maintenance of the corneal homeostasis. The corneal barrier dysfunction may be associated with the pathogenesis of a number of eye diseases. In this study, we assessed the expression of epithelial cell adhesion molecule-1 (ECAM1) in human corneal epithelial cells (HCE). The epithelial barrier function of the corneal epithelial monolayer was determined in Transwells. We found that the HCE cells expressed ECAM1. Knockdown of ECAM1 markedly compromised the HCE monolayer barrier function. A complex of ECAM1, claudin1, and occludin was detected in the HCE monolayers, which was not detected in the ECAM1-null HCE monolayers. Exposure to the proinflammatory cytokine, interleukin-13, inhibited the expression of ECAM1 in HCE cells and compromised the barrier function, which was prevented in the HCE monolayer with the ECAM1 overexpression. In conclusion, ECAM1 is required in the formation of the tight junction complex and maintaining the corneal epithelial barrier function.

Spatiotemporally Regulated Ablation of Klf4 in Adult Mouse Corneal Epithelial Cells Results in Altered Epithelial Cell Identity and Disrupted Homeostasis.

In previous studies, conditional disruption of Klf4 in the developing mouse ocular surface from embryonic day 10 resulted in corneal epithelial fragility, stromal edema, and loss of conjunctival goblet cells, revealing the importance of Klf4 in ocular surface maturation. Here, we use spatiotemporally regulated ablation of Klf4 to investigate its functions in maintenance of adult corneal epithelial homeostasis. Expression of Cre was induced in ternary transgenic (Klf4(LoxP/LoxP)/Krt12(rtTA/rtTA)/Tet-O-Cre) mouse corneal epithelium by doxycycline administered through intraperitoneal injections and drinking water, to generate corneal epithelium-specific deletion of Klf4 (Klf4(Δ/ΔCE)). Corneal epithelial barrier function was tested by fluorescein staining. Expression of selected Klf4-target genes was determined by quantitative PCR (QPCR), immunoblotting, and immunofluorescent staining. Klf4 was efficiently ablated within 5 days of doxycycline administration in adult Klf4(Δ/ΔCE) corneal epithelium. The Klf4(Δ/ΔCE) corneal epithelial barrier function was disrupted, and the basal cells were swollen and rounded after 15 days of doxycycline treatment. Increased numbers of cell layers and Ki67-positive proliferating cells suggested deregulated Klf4(Δ/ΔCE) corneal epithelial homeostasis. Expression of tight junction proteins ZO-1 and occludin, desmosomal Dsg and Dsp, basement membrane laminin-332, and corneal epithelial-specific keratin-12 was decreased, while that of matrix metalloproteinase Mmp9 and noncorneal keratin-17 increased, suggesting altered Klf4(Δ/ΔCE) corneal epithelial cell identity. Ablation of Klf4 in the adult mouse corneas resulted in the absence of characteristic corneal epithelial cell differentiation, disrupted barrier function, and squamous metaplasia, revealing that Klf4 is essential for maintenance of the adult corneal epithelial cell identity and homeostasis.

Activation of toll like receptor-3 induces corneal epithelial barrier dysfunction

The epithelial barrier is critical in the maintenance of the homeostasis of the cornea. A number of eye disorders are associated with the corneal epithelial barrier dysfunction. Viral infection is one common eye disease type. This study aims to elucidate the mechanism by which the activation of toll like receptor 3 (TLR3) in the disruption of the corneal epithelial barrier. In this study, HCE cells (a human corneal epithelial cell line) were cultured into epithelial layers using as an in vitro model of the corneal epithelial barrier. PolyI:C was used as a ligand of TLR3. The transepithelial electric resistance (TER) and permeability of the HCE epithelial layer were assessed using as the parameters to evaluate the corneal epithelial barrier integrity. The results showed that exposure to PolyI:C markedly decreased the TER and increased the permeability of the HCE epithelial layers; the levels of cell junction protein, E-cadherin, were repressed by PolyI:C via increasing histone deacetylase-1 (HDAC1), the latter binding to the promoter of E-cadherin and repressed the transcription of E-cadherin. The addition of butyrate (an inhibitor of HDAC1) to the culture blocked the corneal epithelial barrier dysfunction caused by PolyI:C. In conclusion, activation of TLR3 can disrupt the corneal epithelial barrier, which can be blocked by the inhibitor of HDAC1.

Diadenosine tetraphosphate improves adrenergic anti-glaucomatous drug delivery and efficiency

The effect of the dinucleotide P1, P4-Di (adenosine-5') tetraphosphate (Ap4A) in improving adrenergic anti-glaucomatous delivery by modifying the tight junction proteins of the corneal epithelium was evaluated. Stratified human corneal epithelial cells (HCLE) were treated with Ap4A (100 μM) for 5 min and TJ protein levels and barrier function were analysed by western blotting and transepithelial electrical resistance (TEER), respectively. Western blot experiments showed a significant reduction at 2 h (45% reduction of ZO-1 and 65% reduction of occludin protein levels) as compared to non-treated (control) cells. Two hours after Ap4A treatment, TEER values were significantly reduced (65% as compared to control levels (p < 0.001)), indicating an increase in corneal barrier permeability. Topical application of Ap4A in New Zealand white rabbits two hours before the instillation of the hypotensor compounds (the α2-adrenergic receptor agonist, brimonidine and the β-adrenergic receptor antagonist, timolol), improved the delivery of these compounds to the anterior chamber as well as their hypotensive action on the intraocular pressure. The results obtained showed that, when Ap4A was topically applied two hours before the adrenergic compounds, the concentration of brimonidine in the aqueous humour increased from 64.3 ± 5.3 nM to 240.6 ± 8.6 nM and from 58.9 ± 9.2 nM to 183.7 ± 6.8 nM in the case of timolol, which also produces a more profound effect on IOP. Therefore, Ap4A treatment results in a better entrance of adrenergic anti-glaucomatous compounds within the eye and consequently improved therapeutic efficiency by increasing corneal epithelial barrier permeability.

The Effect of Rebamipide on Ocular Surface Disorders Induced by Latanoprost and Timolol in Glaucoma Patients.

Purpose. To examine the efficacy of ophthalmic rebamipide suspensions on ocular surface disorders induced by antiglaucoma eye drops. Patients and Methods. Forty eyes of 40 patients receiving latanoprost (0.005%) and timolol (0.5%) were included in this randomized prospective study. The patients were randomly divided into two groups (n = 20): the rebamipide-treated group and control group. Changes in intraocular pressure, tear film break-up time (TBUT), and corneal epithelial barrier function were evaluated at baseline, 4 weeks, and 8 weeks after rebamipide administration. Furthermore, superficial punctate keratopathy severity was evaluated by scoring the lesion area and density. Results. There was no significant difference in intraocular pressure before and after rebamipide treatment. However, corneal epithelial barrier function improved significantly 4 and 8 weeks after rebamipide treatment. TBUT was partially, but significantly, increased (P = 0.02) 8 weeks after rebamipide treatment, whereas no significant change was observed at 4 weeks. Additionally, a significant decrease in area and density of keratopathy was observed 8 weeks after rebamipide treatment but not at 4 weeks. The control group showed no significant difference compared to baseline. Conclusions. Our data suggests that rebamipide treatment may reduce the occurrence of drug-induced ocular surface disorder.

Diadenosine tetraphosphate induces tight junction disassembly thus increasing corneal epithelial permeability.

Here, we have studied the effects of the dinucleotide P(1), P(4)-Di (adenosine-5') tetraphosphate (Ap4 A) on corneal barrier function conferred by the tight junction (TJ) proteins and its possible involvement in ocular drug delivery and therapeutic efficiency. Experiments in vitro were performed using human corneal epithelial cells (HCLEs) treated with Ap4 A (100 μM) for 5 min. Western blot analysis and transepithelial electrical resistance (TEER) were performed to study the TJ protein levels and barrier function respectively. Intracellular pathways involved were determined using an ERK inhibitor and P2Y(2) receptor siRNAs. In in vivo assays with New Zealand rabbits, TJ integrity was examined by zonula occludens-1 (ZO-1) staining. The hypotensive compound 5-methoxycarbonylamino-N-acetyltryptamine (5-MCA-NAT) was used to assess improved delivery, measuring its levels by HPLC and measuring intraocular pressure using 5-MCA-NAT, P2Y receptor antagonists and P2Y2 siRNAs. Two hours after Ap4 A pretreatment, TJ protein levels in HCLE cells were reduced around 40% compared with control. TEER values were significantly reduced at 2 and 4 h (68 and 52% respectively). TJ reduction and ERK activation were blocked by the ERK inhibitor U012 and P2Y(2) siRNAs. In vivo, topical application of Ap4 A disrupted ZO-1 membrane distribution. 5-MCA-NAT levels in the aqueous humour were higher when Ap4 A was previously instilled and its hypotensive effect was also increased. This action was reversed by P2Y receptor antagonists and P2Y(2) siRNA. Ap4 A increased corneal epithelial barrier permeability. Its application could improve ocular drug delivery and consequently therapeutic efficiency.

Increased corneal epithelial permeability after overnight sleep.

To investigate factors of ethnicity, sex, age, and diurnal variation on human corneal epithelial permeability. Data of corneal epithelial permeability to sodium fluorescein (Pdc) were collected from 374 noncontact lens wearers at various times after awakening throughout the day. Mixed-effect models were developed to investigate the association between Pdc and factors of interest, including time awake (TA), age, sex, ethnicity, and interactions of these factors. Two models evaluated the "Pdc recovery period" from awakening to 2 hours (Model 1) and the "Pdc plateau" period after TA of 2 hours (Model 2). In Model 1, Pdc declined significantly with length of awake time (P = 0.000), and showed higher Pdc with males (P = 0.098), although this sex difference was not observed after 2 hours (Model 2). Both models showed significantly higher Pdc in Asians than in non-Asians (P = 0.000) and increased Pdc with age (P = 0.048, P = 0.001). Baseline corneal epithelial barrier function increases after overnight sleep and varies significantly by ethnicity and age.

Mice lacking inositol 1,4,5-trisphosphate receptors exhibit dry eye.

Tear secretion is important as it supplies water to the ocular surface and keeps eyes moist. Both the parasympathetic and sympathetic pathways contribute to tear secretion. Although intracellular Ca2+ elevation in the acinar cells of lacrimal glands is a crucial event for tear secretion in both the pathways, the Ca2+ channel, which is responsible for the Ca2+ elevation in the sympathetic pathway, has not been sufficiently analyzed. In this study, we examined tear secretion in mice lacking the inositol 1,4,5-trisphosphate receptor (IP3R) types 2 and 3 (Itpr2−/−;Itpr3−/−double-knockout mice). We found that tear secretion in both the parasympathetic and sympathetic pathways was abolished in Itpr2−/−;Itpr3−/− mice. Intracellular Ca2+ elevation in lacrimal acinar cells after acetylcholine and epinephrine stimulation was abolished in Itpr2−/−;Itpr3−/− mice. Consequently, Itpr2−/−;Itpr3−/− mice exhibited keratoconjunctival alteration and corneal epithelial barrier disruption. Inflammatory cell infiltration into the lacrimal glands and elevation of serum autoantibodies, a representative marker for Sjögren’s syndrome (SS) in humans, were also detected in older Itpr2−/−;Itpr3−/− mice. These results suggested that IP3Rs are essential for tear secretion in both parasympathetic and sympathetic pathways and that Itpr2−/−;Itpr3−/− mice could be a new dry eye mouse model with symptoms that mimic those of SS.

Influence of Different Additives and Their Concentrations on Corneal Toxicity and Antimicrobial Effect of Benzalkonium Chloride

The aim of this study was to examine the ophthalmic additives responsible for modulating acute corneal epithelial toxicity induced by benzalkonium chloride (BAC) and investigate the ability of polyoxyethylene hydrogenated castor oil 40 (HCO-40) and polysorbate 80 (PS-80) to reduce the corneal toxicity and antimicrobial effects of BAC. Cytotoxicity of the additives, which included glycerin, polyvinyl alcohol, propylene glycol, polyethylene glycol, and PS-80, on rabbit corneal epithelial cells was examined using the cell proliferation assay in the presence and absence of 0.02% BAC. The corneal transepithelial electrical resistance change after a 60-second exposure to HCO-40 or PS-80 mixed with 0.02% BAC was measured in living rabbits. Corneal damage was examined using scanning electron microscopy. The antimicrobial activities of HCO-40 and PS-80 with 0.02% BAC against Staphylococcus aureus, Propionibacterium acnes, Pseudomonas aeruginosa, Escherichia coli, and Streptococcus pneumoniae were assessed. Of all the tested additives, only PS-80 could prevent the BAC-induced cytotoxicity. Corneal epithelial barrier function disorder caused by 0.02% BAC was significantly alleviated by either PS-80 or HCO-40 in a concentration-dependent manner. Scanning electron microscopy images showed an improvement of BAC-induced corneal epithelial toxicity after the addition of HCO-40 or PS-80. The antimicrobial effect of the BAC against P. aeruginosa, E. coli, and S. pneumoniae was reduced after adding HCO-40 or PS-80. HCO-40 and PS-80 reduce acute corneal toxicity and the antimicrobial effect of BAC. Possible interactions between BAC and other additives should be taken into consideration when evaluating the toxicity and antibacterial properties of BAC.

Effects of Eye Drops Containing a Mixture of Omega-3 Essential Fatty Acids and Hyaluronic Acid on the Ocular Surface in Desiccating Stress-induced Murine Dry Eye

Purpose: To investigate the efficacy of the topical application of omega-3 essential fatty acids (EFAs) and hyaluronic acid (HA) mixtures in a mouse model of experimental dry eye (EDE).Methods: Eye drops consisting of 0.1% HA, 0.02%, or 0.2% omega-3 EFAs alone and mixture of 0.02%, or 0.2% omega-3 EFAs and 0.1% HA were applied in desiccating stress-induced murine dry eye. Corneal irregularity scores and fluorescein staining scores were measured 5 and 10 days after treatment. Levels of interleukin (IL)-1β, -17, and interferon gamma-induced protein (IP)-10 were measured in the conjunctiva at 10 days using a multiplex immunobead assay. The concentrations of hexanoyl-lys (HEL) and 4-hydroxynonenal (4-HNE) in conjunctiva tissue were measured with enzyme-linked immunosorbent assays.Results: Mice treated with the mixture containing 0.2% omega-3 EFAs showed a significant improvement in corneal irregularity scores and corneal fluorescein staining scores compared with EDE, HA, 0.02% or 0.2% omega-3 EFAs alone, and 0.02% omega-3 EFAs mixture-treated mice. A significant decrease in the levels of IL-1β, -17, and IP-10 were observed in the 0.2% EFAs mixture-treated group, compared with the other groups. In the mice treated with the mixture containing 0.2% omega-3 EFAs, the concentration of 4-HNE was also lower than the other groups. Although 0.2% omega-3 EFAs alone group also had a significant improvement in corneal irregularity scores and IL-17, IL-10, and 4 HNE levels compared with the other groups, the efficacy was lower than 0.2% omega-3 mixture group.Conclusions: Topically applied eye drops containing a mixture of omega-3 EFAs and HA could improve corneal irregularity and corneal epithelial barrier disruption, and decrease inflammatory cytokines and oxidative stress markers on the ocular surface. Topical omega-3 EFAs and HA mixture may have a greater therapeutic effect on clinical signs and inflammation of dry eye compared with HA artificial tears.

Notch signaling in pathogenesis of diseases

The Notch signaling pathway functions on cell fate decisions in a variety of different organizations in multicellular organisms, such as the hematopoietic system, nervous system, vascular system, skin and pancreas. In the majority of cases, Notch signaling blocks cell differentiation towards a primary process, and instead, direct them to a second differentiation. Altering the differentiation program or forcing it to remain in the undifferentiated state, there are several human diseases linked to defects in genes involved in Notch signaling, aberrant Notch signaling has been observed in a number of human cancers, suggesting a possible role of Notch signaling in tumor formation. Further, Recent study demonstrated an essential role for Notch1 in the corneal epithelial barrier recovery after wounding. We systematically searched the electronic PubMed database for research articles about Notch gene polymorphisms and diseases up to October 2013. Revman 5.0 software was adopted to conduct the meta-analysis. Crude odds ratio (ORs) and 95% confidence intervals (95% CIs) were calculated by either fixed-effects model or random-effects model. The present meta-analysis suggests that Notch gene polymorphisms are associated with the susceptibility of many diseases especially cancer.

Notch signaling in pathogenesis of diseases

The Notch signaling pathway functions on cell fate decisions in a variety of different organizations in multicellular organisms, such as the hematopoietic system, nervous system, vascular system, skin and pancreas. In the majority of cases, Notch signaling blocks cell differentiation towards a primary process, and instead, direct them to a second differentiation. Altering the differentiation program or forcing it to remain in the undifferentiated state, there are several human diseases linked to defects in genes involved in Notch signaling, aberrant Notch signaling has been observed in a number of human cancers, suggesting a possible role of Notch signaling in tumor formation. Further, Recent study demonstrated an essential role for Notch1 in the corneal epithelial barrier recovery after wounding. We systematically searched the electronic PubMed database for research articles about Notch gene polymorphisms and diseases up to October 2013. Revman 5.0 software was adopted to conduct the meta-analysis. Crude odds ratio (ORs) and 95% confidence intervals (95% CIs) were calculated by either fixed-effects model or random-effects model. The present meta-analysis suggests that Notch gene polymorphisms are associated with the susceptibility of many diseases especially cancer.