Topical Osmoprotectant for the Management of Postrefractive Surgery-Induced Dry Eye Symptoms: A Randomised Controlled Double-Blind Trial.

BACKGROUND: Dry eye disease (DED) is one of the most common complications following refractive surgery. PURPOSE: Evaluate the efficacy of an osmoprotective eye drop (Optive®) for the management of induced DED in refractive surgery patients. DESIGN: Double-masked randomised controlled trial. METHODS: Twenty-two refractive surgery patients oriented to apply FreshTears (FT; n = 13) or Optive (Op; n = 9), topically, QID, for 3 months. Eye exams were performed before surgery (T0) and 1-month (T1) and 3-month (T3) follow-up and consisted of tear film osmolarity, Schirmer 1 test, tear film breakup time (TBUT), fluorescein staining, and ocular surface disease index (OSDI) and patient symptoms questionnaires. MAIN OUTCOME MEASURES: Pain and osmolarity. RESULTS: Pain increased significantly for FT at T3 (p < 0.05). A reduction in osmolarity was observed at T1 and T3 for Op group (p < 0.01) and at T3 for FT group (p < 0.05). TBUT showed a decrease between T0 and T1 for FT (p < 0.05). Schirmer 1 values increased significantly for Op in T1. CONCLUSIONS: Op was superior to FT in regard to pain, osmolarity, TBUT, and Schirmer 1. Osmoprotectant solutes, such as L-carnitine, could attenuate inflammation and secondary DED. Osmoprotective lubricants can be effectively applied for the prevention of refractive surgery-related dry eye symptoms and signs.

Human immature dental pulp stem cells share key characteristic features with limbal stem cells.

OBJECTIVES: Limbal stem cells (LSC) are self-renewing, highly proliferative cells in vitro, which express a set of specific markers and in vivo have the capacity to reconstruct the entire corneal epithelium in cases of ocular surface injury. Currently, LSC transplantation is a commonly used procedure in patients with either uni- or bilateral total limbal stem cells deficiency (TLSCD). Although LSC transplantation holds great promise for patients, several problems need to be overcome. In order to find an alternative source of cells that can partially substitute LSC in cornea epithelium reconstruction, we aimed at investigating whether human immature dental pulp stem cells (hIDPSC) would present similar key characteristics as LSC and whether they could be used for corneal surface reconstruction in a rabbit TLSCD model. MATERIALS: We used hIDPSC, which co-express mesenchymal and embryonic stem cell markers and present the capacity to differentiate into derivative cells of the three germinal layers. TLSCD was induced by chemical burn in one eye of rabbits. After 30 days, the opaque tissue formed was removed by superficial keratectomy. Experimental group received undifferentiated hIDPSC, while control group only received amniotic membrane (AM). Both groups were sacrificed after 3 months. RESULTS AND CONCLUSIONS: We have demonstrated, using immunohistochemistry and reverse transcription-polymerase chain reaction, that hIDPSCs express markers in common with LSC, such as ABCG2, integrin beta1, vimentin, p63, connexin 43 and cytokeratins 3/12. They were also capable of reconstructing the eye surface after induction of unilateral TLSCD in rabbits, as shown by morphological and immunohistochemical analysis using human-specific antibodies against limbal and corneal epithelium. Our data suggest that hIDPSCs share similar characteristics with LSC and might be used as a potential alternative source of cells for corneal reconstruction.

Predictive index to differentiate invasive squamous cell carcinoma from preinvasive ocular surface lesions by impression cytology.

BACKGROUND/AIMS: In the literature, no cytological features have been identified that reliably differentiate invasive squamous cell carcinoma (SCC) from preinvasive lesions in impression cytology (IC) samples. The aim was to identify cytological features related to malignancy and apply them in a quantitative model to determine an index score with the best predictive power to differentiate SCC from preinvasive ocular surface lesions by IC. METHODS: 39 patients with ocular surface epithelial lesions were enrolled. IC was obtained from all lesions before surgical excision. Specimens with atypical cells were evaluated regarding 11 cytological parameters based on the 2001 Bethesda system. RESULTS: Histopathological diagnosis was pterygium in one case, actinic keratosis in nine cases, intraepithelial neoplasia in nine cases and SCC in 20 cases. Analysis of the receiver operating characteristic curve revealed that a predictive index score (cut-off point) > or =4.25 presented the best relationship between sensitivity and specificity in identifying SCC (sensitivity of 95%, specificity of 93%, positive predictive value of 95% and negative predictive value of 93%). CONCLUSION: The scoring system model presented is suitable for clinical practice in differentiating SCC from preinvasive ocular surface lesions by IC and can be better evaluated with prospective use.

Sodium hyaluronate (hyaluronic acid) promotes migration of human corneal epithelial cells in vitro.

PURPOSE: Sodium hyaluronate (hyaluronic acid) is known to promote corneal epithelial wound healing in vivo and in vitro, in animal experiments. Sodium hyaluronate is the ligand for CD44, a cell surface adhesion molecule which has been found on normal human corneal epithelial cells. The purpose of this study was to investigate the effect of sodium hyaluronate on human corneal epithelial cell migration, proliferation, and CD44 receptor expression. METHODS: Human corneal epithelial cell cultures were established from 32 donor corneoscleral rims and maintained separately in three different culture conditions: (1) culture medium only, (2) sodium hyaluronate enriched (0.6 mg/ml) medium, and (3) hydroxypropylmethylcellulose enriched (2.5 mg/ml) medium. The total area of migrating epithelial cell sheets in each case was measured by planimetry on days 4, 8, 12, and 16. Cytospin preparations of cells cultured in the different culture conditions were examined immunohistochemically for proliferation and CD44 receptor expression using antibodies directed against Ki67 and CD44 respectively. RESULTS: Cells cultured in the presence of sodium hyaluronate showed significantly increased migration at days 12 and 16 (Friedmen test: p = 0.0012, day 16; p = <0.001, day 12) compared with cells cultured in the other media. There was no difference in cell proliferation (Ki67) or CD44 expression on cells cultured in the different culture conditions. CONCLUSIONS: Sodium hyaluronate promotes migration but not proliferation or CD44 expression on human corneal epithelial cells in vitro. The beneficial effect of sodium hyaluronate in corneal wound healing is likely to be related to rapid migration of cells leading to rapid wound closure. This may be facilitated by the adhesion between CD44 on the cells and hyaluronic acid, which coats the surface of the denuded cornea.

Ocular surface epithelium induces expression of human mucosal lymphocyte antigen (HML-1) on peripheral blood lymphocytes.

BACKGROUND/AIMS: Peripheral blood CD8+ lymphocytes that home to mucosal surfaces express the human mucosal lymphocyte antigen (HML-1). At mucosal surfaces, including the ocular surface, only intraepithelial CD8+ lymphocytes express HML-1. These lymphocytes are retained in the intraepithelial compartment by virtue of the interaction between HML-1 and its natural ligand, E-cadherin, which is expressed on epithelial cells. The purpose of this study was to determine whether ocular surface epithelial cells (ocular mucosa) could induce the expression of human mucosal lymphocyte antigen on peripheral blood lymphocytes. METHODS: Human corneal and conjunctival epithelial cells were co-cultured with peripheral blood lymphocytes. Both non-activated and activated lymphocytes were used in the experiments. After 7 days of incubation, lymphocytes were recovered and analysed for the antigens CD8/HML-1, CD4/HML-1, CD3/CD8, CD3/CD4, CD3/CD25, CD8/CD25, and CD4/CD25 by flowcytometry. RESULTS: Significant statistical differences were observed in the CD8/HML-1 expression when conjunctival epithelial cells were co-cultured with non-activated and activated lymphocytes (p = 0.04 for each) and when corneal epithelial cells were co-cultured with non-activated lymphocytes (p = 0.03). Significant statistical difference in CD4/HML-1 expression was observed only when conjunctival epithelial cells were co-cultured with activated lymphocytes (p = 0.02). CONCLUSION: Ocular surface epithelial cells can induce the expression of human mucosal lymphocyte antigen on CD8+ (and to some extent on CD4+) lymphocytes. This may allow the retention of CD8+ and CD4+ lymphocytes within the epithelial compartment of the conjunctiva and play a part in mucosal homing of lymphocytes.