The Key Role of VEGF in the Cross Talk between Pterygium and Dry Eye and Its Clinical Significance.

PURPOSE: To examine whether dry eye severity is a risk factor for pterygium activity and whether vascular endothelial growth factor (VEGF) is crucial in the cross talk between pterygium and dry eye. METHODS: A total of 103 patients with primary pterygium (Pteg) were included in the study group; they were divided into 2 groups according to the complication of dry eye (DE) (Pteg + DE group, Pteg - DE group). Further, 60 patients with just dry eye (DE group) and 60 normal individuals (normal) were included as 2 control groups. DE severity and pterygium activity were measured, and unstimulated tear samples and pterygium tissues were collected for cytokine detection. RESULTS: (1) Tear detection: VEGF expression increased in the Pteg + DE group compared to the Pteg - DE, DE, and normal control groups; VEGF was especially increased in the active Pteg + DE group. VEGF concentration was positively correlated with pterygium activity. (2) Tissue detection: the mRNA expression of VEGF was upregulated in the active pterygium group. CONCLUSIONS: Inflammation played an important role in the development of dry eye and pterygium. VEGF was the core molecule in the cross talk, which might explain the high incidence of the coexistence of these 2 diseases.

Reconstruction of auto-tissue-engineered lamellar cornea by dynamic culture for transplantation: a rabbit model.

To construct an auto-tissue-engineered lamellar cornea (ATELC) for transplantation, based on acellular porcine corneal stroma and autologous corneal limbal explants, a dynamic culture process, which composed of a submersion culture, a perfusion culture and a dynamic air-liquid interface culture, was performed using appropriate parameters. The results showed that the ATELC-Dynamic possessed histological structure and DNA content that were similar to native lamellar cornea (NLC, p>0.05). Compared to NLC, the protein contents of zonula occludens-1, desmocollin-2 and integrin ß4 in ATELC-Dynamic reached 93%, 89% and 73%, respectively. The basal cells of ATELC-Dynamic showed a better differentiation phenotype (K3-, P63+, ABCG2+) compared with that of ATELC in static air-lift culture (ATELC-Static, K3+, P63-, ABCG2-). Accordingly, the cell-cloning efficiency of ATELC-Dynamic (9.72±3.5%) was significantly higher than that of ATELC-Static (2.13±1.46%, p<0.05). The levels of trans-epithelial electrical resistance, light transmittance and areal modulus variation in ATELC-Dynamic all reached those of NLC (p>0.05). Rabbit lamellar keratoplasty showed that the barrier function of ATELC-Dynamic was intact, and there were no signs of epithelial shedding or neovascularization. Furthermore, the ATELC-Dynamic group had similar optical properties and wound healing processes compared with the NLC group. Thus, the sequential dynamic culture process that was designed according to corneal physiological characteristics could successfully reconstruct an auto-lamellar cornea with favorable morphological characteristics and satisfactory physiological function.

Comparative study of the effects of recombinant human epidermal growth factor and basic fibroblast growth factor on corneal epithelial wound healing and neovascularization in vivo and in vitro.

PURPOSE: This study was undertaken to investigate the effects of recombinant human epidermal growth factor (rhEGF) and basic fibroblast growth factor (bFGF) on corneal wound healing and neovascularization (CNV). METHODS: The positive effects of 10 ng/ml rhEGF and bFGF on the proliferation of corneal epithelial cells (SD-HCEC1s), rabbit keratocyte cells (RKCs) and human umbilical vein endothelial cells (HUVECs) as well as the effects on the migration capacity on HUVECs were observed. An animal central corneal wound and CNV model was established in rabbits. One eye of each group was chosen randomly for topical administration of rhEGF, bFGF or normal saline, and variability in the area of corneal epithelial wound healing and CNV was observed. RESULTS: The optimal concentration of rhEGF and bFGF for the proliferation of corneal epithelial cells was 10 ng/ml. The promotive effect of 10 ng/ml rhEGF on the proliferation of RKCs and HUVECs was less than that of 10 ng/ml bFGF. In the animal experiment, the healing rate of the corneal epithelium in the rhEGF group was better than in the other groups on day 1. On day 3, the healing rates of the 3 groups were nearly equal. The CNV area in the rhEGF group was less than that of the bFGF group. CONCLUSIONS: rhEGF and bFGF both had promotive effects on corneal epithelial wound healing, but rhEGF had a weaker promotive effect on CNV than bFGF. With long-term application of growth factor drugs, rhEGF is suggested for lessening the growth of CNV.

[Study on the treatment of dry eye with Loteprednol Etabonate].

OBJECTIVE: To observe the efficacy and safety of 0.5% Loteprednol Etabonate ophthalmic suspension in the treatment of moderate dry eye. METHODS: Totally 34 dry eye patients (68 eyes) in grade 2 or grade 3 (DEWS standard) enrolled in our hospital from March 2009 to September 2010 were randomly divided into two groups: the experimental group (Loteprednol Etabonate Group) and the control group (Cyclosporine A, CsA group). 0.5% Loteprednol Etabonate ophthalmic suspension or 1% CsA eye drops was applied 2 times a day respectively together with 0.2% Liposic eye drops (4 - 6 times/day). Questionnaire was used in these patients before the treatment and repeated every 2 weeks during the treatment till 8 weeks. Slit lamp microscope examination, fluorescent staining, tear break-up time (BUT), Schirmer I test (SIt) and intraocular pressure measurement were carried out at the same time point. The conjunctival impression cytology (IC) was performed before the treatment and 8 weeks after the treatment. The mean of the results were compared by t-tests and χ(2) test. RESULTS: After 2 weeks of the treatment, the mean score of the questionnaire was significantly lower than that before the treatment in each group (t = 5.36, 3.63, P < 0.01). After 4 weeks of the treatment, the inflammation of the ocular surface was relieved obviously in both group and the mean score of the corneal fluorescein staining (FL) was lower than that before the treatment in each group. The average density of the goblet cells before the treatment was (181.2 ± 16.1)/mm(2) and (179.4 ± 17.5)/mm(2) in each group respectively. After 8 weeks of the treatment, this increased to (348.6 ± 22.5)/mm(2) and (360.4 ± 27.8)/mm(2) significantly (t = 16.9, 16.3, P < 0.05). BUT was significantly prolonged in each group after the treatment (P < 0.01). There was no significant change in ST I or NCT in each group (P > 0.05). CONCLUSIONS: Topical 0.5% Loteprednol Etabonate ophthalmic suspension is safe and effective for the treatment of moderate dry eye.

Research on the stability of a rabbit dry eye model induced by topical application of the preservative benzalkonium chloride.

BACKGROUND: Dry eye is a common disease worldwide, and animal models are critical for the study of it. At present, there is no research about the stability of the extant animal models, which may have negative implications for previous dry eye studies. In this study, we observed the stability of a rabbit dry eye model induced by the topical benzalkonium chloride (BAC) and determined the valid time of this model. METHODS AND FINDINGS: Eighty white rabbits were randomly divided into four groups. One eye from each rabbit was randomly chosen to receive topical 0.1% BAC twice daily for 2 weeks (Group BAC-W2), 3 weeks (Group BAC-W3), 4 weeks (Group BAC-W4), or 5 weeks (Group BAC-W5). Fluorescein staining, Schirmer's tests, and conjunctival impression cytology were performed before BAC treatment (normal) and on days 0, 7, 14 and 21 after BAC removal. The eyeballs were collected at these time points for immunofluorescence staining, hematoxylin and eosin (HE) staining, and electron microscopy. After removing BAC, the signs of dry eye in Group BAC-W2 lasted one week. Compared with normal, there were still significant differences in the results of Schirmer's tests and fluorescein staining in Groups BAC-W3 and BAC-W4 on day 7 (P<0.05) and in Group BAC-W5 on day 14 (P<0.05). Decreases in goblet cell density remained stable in the three experimental groups at all time points (P<0.001). Decreased levels of mucin-5 subtype AC (MUC5AC), along with histopathological and ultrastructural disorders of the cornea and conjunctiva could be observed in Group BAC-W4 and particularly in Group BAC-W5 until day 21. CONCLUSIONS: A stable rabbit dry eye model was induced by topical 0.1% BAC for 5 weeks, and after BAC removal, the signs of dry eye were sustained for 2 weeks (for the mixed type of dry eye) or for at least 3 weeks (for mucin-deficient dry eye).

Inflammatory cytokine profiles in the tears of thyroid-associated ophthalmopathy.

PURPOSE: To investigate the levels of seven inflammatory cytokines and one chemokine in tears of patients with thyroid-associated ophthalmopathy (TAO) and asymptomatic control subjects, and determine the correlations between tear inflammatory mediators and clinical parameters. METHODS: Prospective observational cohort study. The study involved 21 patients with TAO and ten asymptomatic controls. TAO patients were divided into active TAO and inactive TAO on the basis of 7-point modified formulation of the clinical activity score (CAS). Ocular Surface Disease Index (OSDI) score, tear film break-up time (BUT) was obtained, and the Schirmer test and fluorescein staining were performed in all participants. Ten microliters of tears were collected for analysis the concentrations of interleukin (IL)-1ß, IL-2, IL-6, IL-10, IL-17 interferon (IFN)-γ, tumor necrosis factor (TNF)-α and one chemokine (IL-8) by multiplex bead analysis. RESULTS: Fluorescein staining scores were higher, BUT scores were shorter, and Schirmer test scores were lower in patients with active TAO and inactive TAO than in control subjects. IL-1ß, IL-6, and IL-8 concentrations in tears were significantly higher in active TAO than inactive TAO and the controls. TNF-α concentration was significantly higher in both active and inactive TAO compared with the controls. IL-17 was significantly higher in active TAO than the controls, and the level of IL-2 was significantly higher in inactive TAO compared with the controls. There were significantly positive correlations between tear IL-1ß, IL-6 and IL-8 levels and CAS in TAO. No significant correlations were found between other cytokine concentrations and clinical parameters in TAO. CONCLUSIONS: The differences of tear inflammatory cytokines between patients with active and inactive TAO indicated that orbital inflammation may be involved in the ocular surface damage of TAO.