Comparison of EphA receptor tyrosine kinases and ephrinA ligand expression to EphB-ephrinB in vascularized corneas.

PURPOSE: Eph cell surface receptors and their ligands, ephrins, are involved in neuronal patterning and neovascularization. Our purpose is to compare and characterize the expression of ephrinA ligands and EphA receptors to ephrinB ligands and EphB receptors in excised mouse corneal tissue, in corneal epithelial and keratocyte cell lines, and during corneal angiogenesis. METHODS: Mouse corneal epithelial cells and keratocytes were immortalized using SV40T antigen viral infection of primary cultures. The immortalized epithelial cells and keratocytes were cloned and characterized using antibodies to keratin, vimentin, integrin alpha5beta1, and alpha-smooth muscle actin. Basic fibroblast growth factor pellets were implanted to induce corneal neovascularization. The eyes of wild-type, ephrinB2(tlacZ/+), and EphB4(tlacZ/+) heterozygous mice were harvested and sectioned 7 days after pellet implantation. Confocal immunohistochemistry was performed to compare the expression of the Eph/ephrinA family (EphA1-8, ephrinA1-5) and Eph/ephrinB family (EphB1-4, EphB6 ephrinB1-3). RESULTS: EphA1, EphA3, ephrinA1, ephrinA2, EphB1, EphB4, ephrinB1, and ephrinB2 were detected in wild-type mouse corneal epithelial cells and keratocytes. EphA2 was immunolocalized only in epithelial cells. Also, EphA3, ephrinA1, EphB1, EphB4, and ephrinB1 were immunolocalized to the corneal epithelium and stroma. In the vascularized corneas, ephrinB1 was immunolocalized mainly to the keratocytes around the vessels, and ephrinB2, EphB1, and EphB4 were colocalized mainly with CD31 to the vascular endothelial cells. CONCLUSIONS: The characterization of ephrin ligand and Eph receptor expression during cornea angiogensis in this study suggests that the Eph/ephrin family of receptor tyrosine kinases and their ligands may play a role in the regulation of corneal angiogenesis.

Corneal infections after implantation of intracorneal ring segments.

PURPOSE: To report risk factors, clinical course, and outcome in patients with infectious keratitis following implantation of intracorneal ring segments (ICRS). METHODS: The records of 8 patients with culture-proven infectious keratitis after ICRS (Ferrara or Intacs) implantation were retrospectively reviewed. Age, gender, corneal findings, ocular abnormalities, the condition that led to ICRS implantation, immediate prior use of a contact lens, elapsed time between implantation and the onset of symptoms, previous medications, and systemic disorders were noted. RESULTS: Culture-positive infectious keratitis developed in 7 eyes of 7 patients (2 men and 5 women) with a mean age of 35 years who underwent Ferrara implantation for the treatment of keratoconus and in a 29-year-old man who underwent Intacs implantation for correction of low myopia. Contact lens use, diabetes, and trauma were factors possibly associated with the risk of infection in three cases. Microorganisms, identified in all cases, included Staphylococcus aureus, Streptococcus viridans, Streptococcus pneumoniae, Pseudomonas sp, Nocardia sp, Klebsiella sp, and Paecylomices sp. Onset of symptoms of infection varied from less than 1 week to 22 months postoperatively, depending on the infecting organism. CONCLUSIONS: Infectious keratitis following ICRS implantation is a sight-threatening complication for which early recognition and rapid institution of appropriate treatment may result in a better visual outcome.

Small pupil phacoemulsification using iris sutures: a new method?

A case is presented in which an alternative surgical method for managing poorly dilating pupils preoperatively or intraoperatively was employed. The technique uses iris sutures, is simple, safe, easily reproducible, and reversible, and does not require new devices for pupil enlargement. This new surgical method is appropriate for extracapsular cataract extraction and phacoemulsification or posterior segment surgeries, and maintains pupillary appearance and function postoperatively. Although other techniques are generally available, this technique may be useful in unique situations where other pupil devices or methods are not available.

Corneal epithelial MT1-MMP inhibits vascular endothelial cell proliferation and migration.

PURPOSE: To determine the effects of corneal epithelial membrane-type 1 matrix metalloproteinase (MT1-MMP) on vascular endothelial migration and proliferation. METHODS: We generated immortalized wild-type, MT1-MMP knockout and MT1-MMP knock-in corneal epithelial cells. Calf pulmonary arterial endothelial (CPAE) cell proliferation and Boyden chamber migration were assayed. RESULTS: Conditioned media from MT1-MMP epithelial knockout cells significantly increased CPAE proliferation 5-bromo-2'-deoxy-uridine (BrdU) incorporation, and CPAE migration as compared with wild-type epithelial cells. Conditioned media from knock-in cells reversed the increase in CPAE proliferation, BrdU incorporation and CPAE migration. Knock-in cells transfected with mutant MT1-MMP (E240A) did not abrogate the reversal effect. CONCLUSIONS: Corneal epithelial MT1-MMP is antiangiogenic. This antiangiogenic activity does not require the catalytic domain.

Effect of MT1-MMP deficiency and overexpression in corneal keratocytes on vascular endothelial cell migration and proliferation.

PURPOSE: To determine the effect of keratocyte-derived MT1-MMP on calf pulmonary artery endothelial cell (CPAE) proliferation and migration. METHODS: Keratocyte lines were generated from MT1-MMP knockout (KO) and wild type (WT) mice. WT keratocytes were transfected with WT or mutant MT1-MMP DNAs (DeltaTC or E240A). The effect of keratocyte-conditioned media on CPAE proliferation and migration was assayed. RESULTS: KO keratocyte conditioned media resulted in the greatest increase of CPAE cell proliferation (190.5+/-6.0%; p<0.01). WT keratocyte conditioned media showed higher CPAE proliferation (155.4+/-3.6%) than WT/MT1-MMP-transfected keratocytes (119.7+/-2.2%; p<0.001). Migration assays confirmed these findings. CONCLUSIONS: Keratocyte-derived MT1-MMP has anti-angiogenic effects in CPAE cells.