Treatment of corneal dermoid with lenticules from small incision lenticule extraction surgery: a surgery assisted by fibrin glue.

AIM: To observe the clinical efficacy of the combined use of small incision lenticule extraction (SMILE)-derived lenticule patches in corneal dermoid excision, with fixation of the lenticule patches assisted by fibrin glue. METHODS: Seventeen eyes of 17 patients with corneal dermoid were treated with dermoid removal combined with SMILE-derived lenticule transplantation. All lenticule patches were fixed by fibrin glue. Ocular changes were assessed using slit lamp microscopy and anterior-segmental optical coherence tomography. The best-corrected visual acuity (BCVA) and ocular dioptric variations were examined preoperatively and postoperatively. Intraocular pressure (IOP) was also monitored in all visited time. RESULTS: Totally, 18 lenticule patches were used on 17 eyes of 17 cornea dermoid patients. The mean follow-up time was 11.47±5.28mo. All lenticule patches were successfully glued, kept on its location and maintained transparent during the follow-up time, with a consecutive epithelial cover for 1wk. Nine of the patients could coordinate visual and optometry exam well. Their preoperative BCVA is 0.60±0.35 in decimal, significantly improved to 0.80±0.26 in decimal at 6mo postoperatively (Z=-2.392, P=0.017), but the changes of their corneal astigmatism diopters showed no significance, with 2.22±1.91 D preoperatively, and 2.28±1.31 D at 6mo postoperatively (Z=-0.135, P=0.893). Limbal pannus formation occurred in 4 (23.52%) cases and decreased with the application of tacrolimus eyedrops. IOP increased in 2 (11.76%) cases, but well decreased by timolol maleate eyedrops. All the adult patients or guardians of minor patients were satisfied with the cosmetic improvement. CONCLUSION: Dermoid excision combined with transplantation of SMILE-derived lenticule patches using fibrin glue is a safe and effective novel tectonic keratoplasty procedure for corneal dermoid.

Suppression of retinal neovascularization by lentivirus-mediated netrin-1 small hairpin RNA.

OBJECTIVES: The function of netrin-1 in pathological angiogenesis and its role in retinal neovascularization were investigated in the retinas of oxygen-induced retinopathy (OIR) mice by inhibition of netrin-1. METHODS: Expression of netrin-1 mRNA and protein in the retinas of OIR mice was analyzed by quantitative RT-PCR and immunoblotting. Inhibition of retinal neovascularization was achieved by lentivirus-mediated netrin-1 small hairpin RNA (shRNA) infection. Retinal neovascularization was examined by fluorescein angiography and quantification of preretinal neovascular nuclei in retinal sections. RESULTS: Both mRNA and protein expression of netrin-1 were significantly upregulated in postnatal day 17 OIR mouse retinas. Treatment of OIR mice with specific lentivirus-mediated netrin-1 shRNA dramatically reduced neovascular outgrowth into the inner limiting membrane. Neovascular tufts and nonperfused areas were also reduced. CONCLUSIONS: High expression of netrin-1 was detected in the retina under ischemic conditions and played a significant role in pathological retinal angiogenesis. Therefore, netrin-1 represents a potential therapeutic target for diabetic retinopathy, retinopathy of prematurity and other ocular neovascular diseases.

Netrin-1 overexpression in oxygen-induced retinopathy correlates with breakdown of the blood-retina barrier and retinal neovascularization.

PURPOSES: Recent research has shown netrin-1 to promote neovascularization. We evaluate the expression of netrin-1 during retinal neovascularization in a murine model of oxygen-induced retinopathy. METHODS: C57BL/6J mice were exposed to 75 ± 5% oxygen for 5 days and returned to room air to induce retinal neovascularization. Retinal neovascularization was observed by fluorescence angiography and was quantified by counting the endothelial nuclei protruding into the vitreous cavity after hematoxylin-eosin staining. RT-PCR and Western blot analyses were used to determine retinal netrin-1 mRNA and protein levels at postnatal days (PN) 13, 15 and 17. RESULTS: In fluorescence angiograms, irregular neovascularization and fluorescein leakage were observed surrounding the unperfused areas in the hypoxic group. The hypoxic group had, on average, 50.70 ± 4.56 neovascular nuclei protruding into the vitreous body, while similar nuclei were absent in the control group. Compared to the normoxic group, there were significant increases in both retinal netrin-1 mRNA and protein levels in the hypoxic group at PN13, PN15 and PN17. CONCLUSION: The netrin-1 level increases in murine retina under hypoxia and may be key in inducing retinal neovascularization.

Expression of Netrin-1 in diabetic rat retina.

PURPOSE: To detect the expression of Netrin-1 in the retinas of diabetic rats and evaluate the relationship between Netrin-1 mRNA and diabetic retinopathy (DR). METHODS: Twenty healthy adult male Sprague-Dawley (SD) rats were randomly divided into a diabetic model group (DM) and a normal control group (NC), each group was composed of ten rats. Sreptozocin (STZ) was administered intraperitoneally at a single dose of 60 mg/kg to diabetic group. The control rats were injected only with citrate buffer. Collection of serum at 72 h after STZ treatment and measuring blood glucose levels confirmed the development of diabetes. The rats with blood glucose level 16.67 mmol/L or higher were considered to be diabetic and were used in the experiment. Retinal tissues were harvested and expression of netrin-1 mRNA and protein in the retina tissues was examined by reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, respectively. RESULTS: Diabetic rats showed classic symptoms of diabetes mellitus, such as polydipsia, polyphagia, and polyuria. Cataract was seen in the DM group at 3 months after administration of STZ. Both netrin-1 mRNA and protein levels retina were dramatically increased in the DM rats compared to the NC group (P < 0.05). CONCLUSION: Diabetic rats can be successfully established by intraperitoneal injection of streptozotocin (60 mg/kg). Netrin-1 may play an important role during the development of diabetic retinopathy.

Expression of FLT4 in hypoxia-induced neovascular models in vitro and in vivo.

AIM: To investigate the expression of FLT4 in retina with oxygen induced retinopathy (OIR) and in brain endothelial cell lines (bEnd3) under hypoxia conditions in mice. METHODS: Fifty-two one-week-old C57BL/6J mice were divided into control group and hypoxia group. The mice of hypoxia group were exposed to 75% oxygen for 5 days and then returned to the room air to induce retinal neovascularization. Mice in control group were raised in the environment of room air at the same time. The expressions of FLT4 mRNA and protein were checked with RT-PCR and Western Blot analysis at postnatal day 14, 17 and 21 ( P14, P17 and P21) respectively. 125mmol/L CoCl(2) were added to the culture medium of bEnd3 cell, proteins were extracted in 12, 24, 48 and 72 hours and FLT4 levels were examined by Western Blot analysis. RESULTS: The mRNA and protein level of FLT4 expressed in P14 and P17 OIR mice retina statistically up-regulated as compared with those in control group, but there was no statistical difference between OIR group and control group at P21. FLT4 levels increased significantly in 12, 24 and 48 hours hypoxia intervened bEnd3 cells, its levels in 72 hours increased mildly but showed no significance. CONCLUSION: FLT4 levels increase in OIR mice retinas and bEnd3 cells in hypoxia. It may play an important role in endothelial cells proliferation in hypoxia and retinal neovascularization in OIR mice.

Intravitreous high expression level of netrin-1 in patients with proliferative diabetic retinopathy.

PURPOSE: To investigate the significance of netrin-1 and vascular endothelial growth factor (VEGF) in the pathogenesis of retinal angiogenesis, the levels of netrin-1 and VEGF in the vitreous fluid and serum of the proliferative diabetic retinopathy (PDR) and non-proliferative diabetic retinopathy (non-PDR) patients were measured. We then determined the netrin-1 and VEGF expression in the oxygen induced retinopathy (OIR) mice retinas. METHODS: A total of 18 eyes from 18 patients were included in our study and 10 of them were collected from PDR patients and 8 from non-PDR patients. Undiluted vitreous fluid samples were collected during pars plana vitrectomy. Appropriate blood samples were collected if possible. Netrin-1 and VEGF levels in the vitreous fluid and plasma were determined by Enzyme-linked Immunosorbent Assays. OIR mice models were established, and netrin-1 and VEGF levels were determined by immunohistochemistry analysis. RESULTS: The levels of netrin-1 and VEGF in the vitreous of PDR patients were significantly higher than those in the controls (Mediannetrin-1=509.94 vs. 85.91 pg/ml, P<0.001 and Median VEGF=762.60 vs. 77.52 pg pg/ml, P<0.001). Netrin-1 was mainly expressed in GCL and INL of the retina in mice. Both netrin-1 and VEGF were up-regulated in OIR mice. CONCLUSION: Netrin-1 and VEGF levels were elevated in vitreous fluid of the PDR patients and the OIR mice retinas. Therefore, netrin-1 may play important roles in pathological retinal angiogenesis.