TAP1, a potential immune-related prognosis biomarker with functional significance in uveal melanoma.

BACKGROUND: TAP1 is an immunomodulation-related protein that plays different roles in various malignancies. This study investigated the transcriptional expression profile of TAP1 in uveal melanoma (UVM), revealed its potential biological interaction network, and determined its prognostic value. METHODS: CIBERSORT and ESTIMATE bioinformatic methods were used on data sourced from The Cancer Genome Atlas database (TCGA) to determine the correlation between TAP1 expression, UVM prognosis, biological characteristics, and immune infiltration. Gene set enrichment analysis (GSEA) was used to discover the signaling pathways associated with TAP1, while STRING database and CytoHubba were used to construct protein-protein interaction (PPI) and competing endogenous RNA (ceRNA) networks, respectively. An overall survival (OS) prognostic model was constructed to test the predictive efficacy of TAP1, and its effect on the in vitro proliferation activity and metastatic potential of UVM cell line C918 cells was verified by RNA interference. RESULTS: There was a clear association between TAP1 expression and UVM patient prognosis. Upregulated TAP1 was strongly associated with a shorter survival time, higher likelihood of metastasis, and higher mortality outcomes. According to GSEA analysis, various immunity-related signaling pathways such as primary immunodeficiency were enriched in the presence of elevated TAP1 expression. A PPI network and a ceRNA network were constructed to show the interactions among mRNAs, miRNAs, and lncRNAs. Furthermore, TAP1 expression showed a significant positive correlation with immunoscore, stromal score, CD8+ T cells, and dendritic cells, whereas the correlation with B cells and neutrophils was negative. The Cox regression model and calibration plots confirmed a strong agreement between the estimated OS and actual observed patient values. In vitro silencing of TAP1 expression in C918 cells significantly inhibited cell proliferation and metastasis. CONCLUSIONS: This study is the first to demonstrate that TAP1 expression is positively correlated with clinicopathological factors and poor prognosis in UVM. In vitro experiments also verified that TAP1 is associated with C918 cell proliferation, apoptosis, and metastasis. These results suggest that TAP1 may function as an oncogene, prognostic marker, and importantly, as a novel therapeutic target in patients with UVM.

Prostaglandin F2α Regulates Adipogenesis by Modulating Extracellular Signal-Regulated Kinase Signaling in Graves' Ophthalmopathy.

Prostaglandin F2α (PGF2α), the first-line anti-glaucoma medication, can cause the deepening of the upper eyelid sulcus due to orbital lipoatrophy. However, the pathogenesis of Graves' ophthalmopathy (GO) involves the excessive adipogenesis of the orbital tissues. The present study aimed to determine the therapeutic effects and underlying mechanisms of PGF2α on adipocyte differentiation. In this study primary cultures of orbital fibroblasts (OFs) from six patients with GO were established. Immunohistochemistry, immunofluorescence, and Western blotting (WB) were used to evaluated the expression of the F-prostanoid receptor (FPR) in the orbital adipose tissues and the OFs of GO patients. The OFs were induced to differentiate into adipocytes and treated with different incubation times and concentrations of PGF2α. The results of Oil red O staining showed that the number and size of the lipid droplets decreased with increasing concentrations of PGF2α and the reverse transcription-polymerase chain reaction (RT-PCR) and WB of the peroxisome proliferator-activated receptor γ (PPARγ) and fatty-acid-binding protein 4 (FABP4), both adipogenic markers, were significantly downregulated via PGF2α treatment. Additionally, we found the adipogenesis induction of OFs promoted ERK phosphorylation, whereas PGF2α further induced ERK phosphorylation. We used Ebopiprant (FPR antagonist) to interfere with PGF2α binding to the FPR and U0126, an Extracellular Signal-Regulated Kinase (ERK) inhibitor, to inhibit ERK phosphorylation. The results of Oil red O staining and expression of adipogenic markers showed that blocking the receptor binding or decreasing the phosphorylation state of the ERK both alleviate the inhibitory effect of PGF2a on the OFs adipogenesis. Overall, PGF2α mediated the inhibitory effect of the OFs adipogenesis through the hyperactivation of ERK phosphorylation via coupling with the FPR. Our study provides a further theoretical reference for the potential application of PGF2α in patients with GO.

Intraorbital wooden foreign bodies: case series and literature review.

Intraorbital wooden foreign bodies (IOWFBs) constitute a relatively rare ocular trauma, which occupy a special type of intraorbital foreign bodies (IOFBs). Data regarding IOWFBs must be obtained from case reports or small case series due to their rarity. Here, we reported 5 cases of IOWFBs and reviewed the related literatures, which could provide comprehensive information regarding the clinical manifestations, diagnosis, and surgical treatment of IOWFBs. Combined with the published literature, a total of 51 independent cases were counted after we added 5 cases. Among them, the number of male and female patients was 35 and 16 respectively; the mean age was 27.3±18.2 (range 1-66)y. Obviously, the disorder seemed to occur mainly in young and middle-aged people. Because of the diversity in the clinical manifestations and imaging characteristics of IOWFBs, misdiagnosis and missed diagnosis often occur during the initial visit. Delayed diagnosis may lead to a high risk of orbital infection caused by IOWFBs. Surgery is the treatment of choice for most patients; however, the missed diagnosis and residue of foreign bodies after previous surgery cannot be ignored. Therefore, an accurate diagnosis is governed by the detailed trauma history, careful ocular examination, close observation of clinical manifestations, correct imaging diagnosis [e.g., magnetic resonance imaging (MRI) or computerized tomography (CT)], and timely and completely elimination of IOWFBs.

Comparison of 2-wall versus 3-wall orbital decompression against dysthyroid optic neuropathy in visual function: A retrospective study in a Chinese population.

ABSTRACT: To compare visual function of 2-wall (medial and lateral) versus 3-wall (medial, lateral, and inferior) orbital decompression in patients with dysthyroid optic neuropathy (DON).A total of 52 eyes of 37 patients underwent orbital decompression for DON between 2013 and 2019 were retrospectively reviewed. Two- or 3-wall decompression was performed in 31 eyes of 23 patients and 21 eyes of 14 patients, respectively. We examined best-corrected visual acuity (BCVA), visual field mean deviation (MD) and pattern standard deviation (PSD), pattern-reversed visual evoked potential (PVEP) for P100 latency and amplitude at 60 and 15 arcmin stimulation checkerboard size, as well as proptosis using Hertel exophthalmometry.Whether 2-wall or 3-wall decompression, all parameters of visual function were improved after surgery (all P < .05). The improvement in BCVA, MD, and PSD was not statistically significant between groups (all P > .05). Proptosis reduction was higher after 3-wall decompression (P = .011). Mean increase in P100 amplitude after 3-wall decompression was statistically higher than that of after 2-wall decompression at 60 and 15 arcmin (P = .045 and .020, respectively), while the mean decrease in P100 latency was similar between the groups (P = .821 and .655, respectively). Six patients (66.67%) had persistent postoperative diplopia and 1 patient (20%) had new-onset diplopia in 3-wall decompression group, which were higher than in 2-wall decompression group (46.15% persistent postoperative diplopia and no new-onset diplopia).Both 2-wall and 3-wall decompression can effectively improve visual function of patients with DON. Three-wall decompression provides better improvement in P100 amplitude and proptosis, however new-onset diplopia is more common with this surgical technique.

Neuroprotective effects of bis(7)-tacrine against glutamate-induced retinal ganglion cells damage.

BACKGROUND: Glutamate-mediated excitotoxicity, primarily through N-methyl-D-aspartate (NMDA) receptors, may be an important cause of retinal ganglion cells (RGCs) death in glaucoma and several other retinal diseases. Bis(7)-tacrine is a noncompetitive NMDA receptors antagonist that can prevent glutamate-induced hippocampal neurons damage. We tested the effects of bis(7)-tacrine against glutamate-induced rat RGCs damage in vitro and in vivo. RESULTS: In cultured neonatal rats RGCs, the MTT assay showed that glutamate induced a concentration- and time-dependent toxicity. Bis(7)-tacrine and memantine prevented glutamate-induced cell death in a concentration-dependent manner with IC50 values of 0.028 microM and 0.834 microM, respectively. The anti-apoptosis effects of bis(7)-tacrine were confirmed by annexin V-FITC/PI staining. In vivo, TUNEL analysis and retrograde labeling analysis found that pretreatment with bis(7)-tacrine(0.2 mg/kg) induced a significant neuroprotective effect against glutamate-induced RGCs damage. CONCLUSIONS: Our results showed that bis(7)-tacrine had neuroprotective effects against glutamate-induced RGCs damage in vitro and in vivo, possibly through the drug's anti-NMDA receptor effects. These findings make bis(7)-tacrine potentially useful for treating a variety of ischemic or traumatic retinopathies inclusive of glaucoma.

[Preliminary study of femtosecond laser sclerostomy ab externo in a rabbit model of chronic ocular hypertension].

OBJECTIVE: To explore the feasibility, efficacy and safety of performing ab externo sclerostomy with a femtosecond laser in rabbits with chronic ocular hypertension. METHOD: The chronic ocular hypertension model was induced by injecting α-chymotrypsin into posterior chamber. Twenty rabbits with chronic ocular hypertension were randomly divided into experiment and control groups, each group consisting of 10 rabbits. An ab externo sclerostomy using a femtosecond laser was performed in the right eyes in the experiment group. The right eyes in control group were unoperated. The laser was a pulsed titanium-sapphire laser, operating at a repetition rate of 1000 per second, 0.4 mJ pulse energy, a central wavelength of 800 nm and a pulse duration of 50 femtoseconds. The survival of filtration blebs, clinical manifestation and intraocular pressure (IOP) were observed for 1 month after surgery. Animals were killed on days 3, 7, 14 and 30 post-operatively. Hematoxylin and eosin (HE) staining and scanning electron microscopy (SEM) were performed to evaluate the histopathologic changes in filtering tracts. The differences in IOP between the experiment and control groups were analyzed by repeated measures analysis of variance. RESULTS: A 2 mm × 1 mm clear full-thickness scleral incision was created in each eye in the experiment group which was hit only once by the laser. The laser treated time was approximately 15 - 16 s. There was a significant difference (F = 117.46, 39.96, 15.17, 11.62, 15.31, 11.10; P < 0.01). IOP between experiment and control groups at post-operatively day 1, 3, 7, 14, 21, 30. No serious intra- or post-operative complications happened in the treated eyes except for anterior chamber hemorrhage in 2 eyes triggered by laser injury to iris root. A conjunctival bleb was successfully formed in all treated eyes at 1 day after surgery and lasted from 14 to 21 days. Histopathology showed that the perforating scleral incisions created by femtosecond laser were sharply defined, with almost no collateral damage to the surrounding tissue. The tissue repair response in the filtering tracts was characterized by mild hyperplasia of fibroblasts and the loose deposition of a small amount of new collagen fibers. CONCLUSION: The current study demonstrates that ab externo femtosecond laser sclerostomy is a feasible, safe and effective option for the treatment of glaucoma.

Intense Pulsed Light Therapy for Patients with Meibomian Gland Dysfunction and Ocular Demodex Infestation.

To observe the clinical changes of meibomian gland dysfunctipn (MGD) and ocular Demodex infestation after intense pulsed light (IPL) treatment to further examine the mechanism of IPL treating patients with MGD and ocular Demodex infestation. The medical records of 25 patients (49 eyes) with MGD treated with IPL, were retrospectively examined to determine outcomes. Associated ocular-surface parameters (ocular surface disease index, OSDI; lipid layer thickness, LLT; noninvasive first breakup time, NIF-BUT; noninvasive average breakup time, NIAvg-BUT; tear film breakup area, TBUA; Schirmer I Test, SIT; corneal fluorescein staining, CFS), eyelid margin abnormalities, meibum quality and expressibility, MG morphological parameters (macrostructure and microstructure), and the number of Demodex infestation were examined before and after treatment. The MG microstructure and the Demodex infestation were examined via in vivo confocal microscopy (IVCM). The results showed that there were statistically significant differences in associated ocular-surface parameters (all P<0.05) before and after IPL treatment, except SIT (P=0.065). Eyelid margin abnormalities, meibum quality and expressibility obviously improved in upper and lower eyelid after IPL treatment (all P<0.0001). MG macrostructure (MG dropouts) decreased in upper (P=0.002) and lower eyelid (P=0.001) after IPL treatment. The nine parameters of MG microstructure in upper and lower eyelid all distinctly improved after IPL treatment (all P<0.0001). The mean number of Demodex mites on the upper lid margin (6.59±7.16 to 3.12±3.81/9 eyelashes) and lower lid margin (2.55±2.11 to 1.29±1.53/9 eyelashes) significantly reduced after IPL treatment (all P<0.0001). The Demodex eradication rate was 20% (8/40) in upper lid margin and 34.15% (14/41) in lower lid margin. These findings indicate that IPL shows great therapeutic potential for patients of MGD and ocular Demodex infestation.

[Structural observation of the anterior chamber angle in CYP1B1-null mice].

OBJECTIVE: To determine the effects of CYP1B1 gene on the structure of anterior chamber angle in mice. METHODS: It is experimental study. Adult CYP1B1-null mice were used, in comparison C57BL/6J mice was used as control. The mice eyes were enucleated and plastic-embedded and the anterior chamber angle were sagittally sectioned in 3 micrometers thickness. The morphology and structure of the eye tissues was studied by light microscopy and transmission electron microscopy. RESULTS: The anterior chamber angle in C57BL/6J mice were well developed. But in CYP1B1-null mice, a variety of anomalies were found in the these tissues, including hypoplastic and compressed trabecular meshwork, abnormal structure of trabecular cells, a basal lamina extending from cornea over the meshwork, small or absent Schlemm's canal, and long iris process extending from the iris root to the trabecular meshwork. These pathological changes was demonstrated focally and the rest of the angle in CYP1B1-null were normal. CONCLUSIONS: CYP1B1 gene plays an important role in the development of the anterior chamber angle. Deletion of this gene leads to the abnormalities in trabecular meshwork, Schlemm's canal and iris process, which may have some influence on the metabolism and function of the outflow facilities.

Whole Body Positron Emission Tomography/Computed Tomography (PET/CT) in the Evaluation of Ophthalmic Tumors.

The clinical value of whole body positron emission tomography/computed tomography (PET/CT) as an imaging tool in diagnosis of ophthalmic tumors was investigated. The retrospective observational case series were performed on the patients with suspected ophthalmic tumors who underwent whole body PET/CT. The golden standard of diagnosis was the final pathological diagnosis or the results of long-term follow-up for patients without surgery/biopsy. PET/CT findings were compared with the golden standard. The sensitivity, specificity, accuracy and positive likelihood ratio of PET/CT in the detection of ophthalmic tumors were calculated. The clinical application of PET/CT in different types of ophthalmic tumors was evaluated. The results showed that 30 patients (18 males and 12 females) with a mean age of 43.0 years (range 4-63 years) were collected. The mean sizes of orbital tumors and intraocular tumors were 26.8 mm×17.8 mm and 11.2 mm×6.1 mm, respectively. The overall sensitivity, specificity, accuracy and positive likelihood ratio of whole body PET/CT in ophthalmic tumors were 76.5%, 71.4%, 75.0% and 2.67, and were 62.5%, 100% and 70.0% in intraocular tumors, and those were 100%, 60.0% and 84.6% in orbital tumors, respectively. PET/CT findings were applied to help make appropriate treatment options in 27 out of 30 patients (90.0%), and 12 (40.0%) patients changed the treatment strategy. False negative results in 4 cases and false positive results in 2 cases were observed in this series. It was suggested that PET/CT was an effective imaging modality in detecting, diagnosing and developing therapeutic schedule for patients with ophthalmic tumors. It was more sensitive and accurate for detecting orbital tumors than for detecting intraocular tumors.

[Analysis of the CYP1B1 gene mutation in primary congenital glaucoma patients of Hubei Han nationality].

OBJECTIVE: To identify novel CYP1B1 gene mutation in primary congenital glaucoma (PCG) patients of Hubei Han nationality and establish the possibility of gene diagnosis of PCG. METHODS: Forty-seven patients with PCG and 100 normal subjects were studied. Genomic DNA was extracted from the peripheral leukocytes of all subjects. Mutation in exon2 and exon3 of CYP1B1 gene was detected in patients and control subjects by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), denaturing high performance liquid chromatograph (DHPLC), and direct sequencing DNA techniques. RESULTS: Compared to normal subjects, a novel mutation was first time identified by direct sequencing demonstrating a homozygous C-to-T transition at codon 385 (CTT to TTT) which produced L385F mutation of CYP1B1 gene in 7 of the 47 patients with PCG. CONCLUSIONS: The novel mutation in exon 3 of CYP1B1 found in PCG patients of Hubei Han nationality was probably pathological mutant gene by nature. It is important that further study be conducted to seek for the specific mutations of CYP1B1 gene and underlying pathological mechanism of PCG patients of Han nationality.

Fixed combination of latanoprost and timolol vs the individual components for primary open angle glaucoma and ocular hypertension: a systematic review and meta-analysis.

AIM: To assess the effects of the fixed combination of 0.005% latanoprost and 0.5% timolol (FCLT) vs their individual components for primary open angle glaucoma (POAG) and ocular hypertension (OHT). METHODS: After searched PubMed, EMBASE, the Cochrane Library and SCI, all randomized controlled clinical trials (RCTs) and cross-over studies were included. The control groups were the mono therapy or the concomitant therapy of latanoprost and timolol. The outcomes were visual field defect, optic atrophy, mean intraocular pressure (IOP) and IOP fluctuation. The analysis was carried out in RevMan version 5.1 software. RESULTS: The post-intervention mean IOP of FCLT was significantly lower compared to timolol [mean difference (MD) -2.92, 95%CI -3.28 to -2.55, P<0.00001] and latanoprost (MD -1.11, 95%CI -1.51 to -0.72, P<0.00001). The post-intervention IOP fluctuation was also significantly lower compared to timolol (MD -0.88, 95%CI -1.23 to -0.53, P<0.00001) and latanoprost (MD -0.63, 95%CI -1.04 to -0.22, P=0.002). The mean IOP was higher in FCLT morning dose group than the one in unfixed combination of 0.005% latanoprost and 0.5% timolol (UFCLT) (MD 1.10, 95%CI 0.81 to 1.39, P<0.00001). Otherwise, there was no difference between FCLT evening dose group and UFCLT (MD 0.34, 95% CI -0.01 to 0.69, P=0.06). There was no statistical difference for the incidence of visual field defect and optic atrophy between FCLT and the monotherapy of components. CONCLUSION: A better IOP lowering effect has been demonstrated for FCLT compared to the mono therapy of components. The IOP lowering effect was worse for FCLT morning dose and almost same for FCLT evening dose compared to the UFCLT. We need more long-term high quality RCTs to demonstrate the outcomes of visual field defect and optic atrophy.

Evaluation of RGD peptide hydrogel in the posterior segment of the rabbit eye.

The aim of this study was to evaluate the biocompatibility and biodegradability of RGD peptide hydrogel in the posterior segment of the eye as a biomaterial potentially useful for sustained drug delivery systems. RGD peptide hydrogel was injected into the vitreous cavity and suprachoroidal space of rabbit eyes. Clinical follow-up and histological observation were performed up to four weeks. The biodegradability was also evaluated by the lifetime of the hydrogel which was defined by ophthalmoscopic observation or ultrasonography. The results showed that RGD peptide hydrogel was well tolerated in the vitreous cavity and suprachoroidal space, and disappeared from the injection sites progressively. As for suprachoroidal injection, the hydrogel was clearly identified by ultrasound echography and was confirmed innoxious to the retinal vessels by fluorescein angiography. Histological observations showed that the structures of retina, choroid and other tissues around the injection site remained normal after the injection. The lifetime of the hydrogel was 25.7 ± 2.65 days and 14.3 ± 3.3 days in the vitreous cavity and suprachoroidal space, respectively. The results obtained demonstrated that RGD peptide hydrogel, which showed excellent biocompatibility and favorable biodegradability in the posterior segment of rabbit eyes, appears to be a promising biomaterial to deliver drugs focally to the choroid and the retina.

Protective effect of saturated hydrogen saline against blue light-induced retinal damage in rats.

AIM: To explore the effect of saturated hydrogen saline on blue light-induced retinal damage in rats. METHODS: The retinal damage of rats was induced by blue light exposure for 6 hours and examined 8 hours, 16 hours and 24 hours after the exposure. One hundred female Sprague-Dawley rats were randomly divided into four groups. Group 1 included 30 rats received light exposure without any other treatment. Group 2 included 30 rats received light exposure with intraperitoneal injection of normal saline. Group 3 included 30 rats received light exposure with intraperitoneal injection of saturated hydrogen saline. And Group 4 included the other 10 rats which did not receive any treatment. The amount of intraperitoneal injection of saturated hydrogen saline and normal saline was calculated in the ratio of 1ml/100g of rat weight. Specimens were collected and processed by H-E staining, ultrastructure observation, biochemical measurement. Morphological changes were observed by light microscope and transmission electron microscope (TEM) and the retinal outer nuclear layer (ONL) thickness was measured by IPP 6.0, while the malondialdehyde (MDA) was measured by colorimetric determination at 532 nm. RESULTS: Although the structure of retina in Group 1 and Group 2 was injured heavily, the injury in Group 3 was mild. The differences between Group 1 and Group 2 were not significant. Compared with the rats in Group 1 and Group 2, the ones in Group 3 had more clearly demarcated retina structure and more ordered cells by light microscope and TEM observation. The ONL thicknesses (400 times) of four groups at each time point except between Group 1 and Group 2 were significantly different (P<0.05). The thicknesses of the ONL in Group 1 at three time points were 30.41±4.04µm, 26.11±2.82µm and 20.63±1.06µm, in Group 2 were 31.62±4.54µm, 25.08±3.63µm and 19.07±3.86µm, in Group 3 were 29.75±3.62µm, 28.83±1.97µm and 27.61±1.83µm. In Group 4 the mean of the thickness was 37.35±1.37µm. As time went by, the damage grew more severely. At 24h point, the differences were most significant. Compared with Group 4, the thickness was 46.23% thinner in Group 1, 50.29% thinner in Group 2 and 28.04% thinner in Group 3. The stack structures of membranous disc in Group 3 were injured slightly, but in Group 1 and Group 2 the damage was more obvious by TEM. Compared with Group 4 at each time point, the content of MDA in Group 1 was higher (P<0.05). The content of MDA in Group 3 was significantly lower than those of Group 1 (P<0.05) and Group 2 (P<0.05). Between the Group 1 and Group 2, the MDA concentration at each time point was no significant difference (P>0.05). CONCLUSION: Saturated hydrogen saline could protect the retina from light-induced damage by attenuating oxidative stress.

External sclerostomy with the femtosecond laser versus a surgical knife in rabbits.

AIM: To experimentally compare the external sclerostomy produced using a femtosecond laser with that made by a surgical knife and to evaluate the healing patterns, efficacy and technical advantages of femtosecond laser sclerostomy. METHODS: In a prospective randomized, controlled, masked-observer study, 10 pigmented rabbits underwent external sclerostomy with a femtosecond laser in the right eye; 10 additional rabbits underwent sclerostomy with a surgical superblade in the right eye. Clinical characteristics, which included bleb morphology and intraocular pressure, were recorded for 1 month after surgery. Six additional rabbits underwent external femtosecond laser sclerostomy in the right eye and mechanical sclerostomy in the left eye and were killed at day 14 after surgery. Histologic staining, immunohistochemistry and scanning electron microscopy were subsequently performed to assess the morphology of the filtering fistula. The titanium-sapphire femtosecond laboratory laser was operating at a repetition rate of 1 kHz, 0.4 mJ pulse energy, a central wavelength of 800nm and a pulse duration of 50 femtoseconds. Mann-Whitney and Kaplan-Meier tests were used for statistical analysis. RESULTS: Successful complete sclerostomy was achieved in each laser-treated eye which was hit only once by the laser. The laser treated time was approximately 15s-16s. In the laser-treated group (n=16), 2 eyes (12%) developed mild hyphema at the site of entry and 8 eyes (50%) showed transient edema in the corneal periphery adjacent to the laser impact zone. The differences between the groups in duration of function blebs and pressure reduction were statistically significant (P=0.025 and 0.016, respectively). The success rate of the laser-treated group was significantly higher than the knife group (P=0.005). Histologically, the subconjunctival connective tissue was loosely arranged with partially patent sclerostomy in the laser-treated eyes at postoperative day 14. This contrasted with the completely scarred sclerostomy tract in the knife group. The mean numbers of fibroblasts and new vessels as well as the amount of new collagen deposition at bleb site were significantly decreased in the laser group (P=0.045, 0.013 and 0.036, respectively). CONCLUSION: The current study demonstrates that external femtosecond laser sclerostomy may offer a safe and effective alternative for the minimally invasive surgical management of glaucoma.

Expression of MMP-2 and MMP-9 in retinoblastoma and their significance.

AIM: To investigate the expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in retinoblastoma (Rb), and their relationships with tumor development stage. METHODS: Immunohistochemical technique was used to detect the expression of MMP-2 and MMP-9 in 41 cases of paraffin embedded Rb samples. Quantitative analysis of the expression of MMP-2 and MMP-9 was assessed by HMIAS-2000 Color Pathologic Analysis System. The differences of the expression of MMP-2 and MMP-9 in each clinical and pathological stage were analyzed statistically. RESULTS: In all the 41 Rb specimens, MMP-2 and MMP-9 expression was found in tumor cells. The expression of MMP-2 and MMP-9 was significantly higher in tumors with optic nerve invasion than in tumors without optic nerve invasion (P<0.05); the expression of MMP-2 and MMP-9 was significantly higher in tumors of extra-ocular stage than in tumors of glaucomatous stage or intra-ocular stage (P<0.05). CONCLUSION: MMP-2 and MMP-9 exist in retinoblastoma cells. The level of MMP-2 and MMP-9 is related to optic nerve invasion and clinical stage of Rb, which suggests the expression of MMP-2 and MMP-9 could be connected to the invasion and development of tumor cells. Further research is needed for deeper understanding of the biological behavior and better evaluation of the prognosis of Rb.

Bis(7)-tacrine protects retinal ganglion cells against excitotoxicity via NMDA receptor inhibition.

AIM: To investigate whether bis(7)-tacrine, a multifunctional drug, inhibits N-methyl-D-aspartate (NMDA) -activated current in retinal ganglion cells(RGC) and provides neuroprotection against retinal cell damage. METHODS: Purified RGC cultures were obtained from retinas of 1-3 days old Sprague-Dawley(SD) rats, following a two-step immunopanning procedure. After 7 days of cultivation, the inhibition of NMDA-activated current by bis(7)-tacrine was measured by using patch-clamp recording techniques. In animal experiments, RGCs were damaged after intravitreal injection of NMDA (5µL, 40nmol) in adult rats. Bis(7)-tacrine(0.05, 0.1, 0.2mg/kg) or memantine(20mg/kg) was intraperitoneal administered to the rats fifteen minutes before intravitreally injection of NMDA. RGC damage was analyzed by histologic techniques, TUNEL and retrograde labeling techniques. RESULTS: Whole-cell patch-clamp recordings demonstrated that NMDA (30µmol/L) resulted in approximately -50 pA inward currents that were blocked by bis(7)-tacrine(1µmol/L). Histological examination and retrograde labeling analysis revealed that bis(7)-tacrine induced a significant neuroprotective effect against NMDA-induced cell damage 7 days after NMDA injection. TUNEL staining showed that pretreatment with bis(7)-tacrine was effective in ameliorating NMDA-induced apoptotic cell loss in the retinal ganglion cell layer 18 hours after injection. CONCLUSION: Bis(7)-tacrine possesses remarkable neuroprotective activities against retinal excitotoxicity through inhibition of NMDA receptors.

Histological observation of RGCs and optic nerve injury in acute ocular hypertension rats.

AIM: To explore the injury of retinal ganglion cells (RGCs) and optic nerves in acute ocular hypertension (OHT) rats. METHODS: We retrogradely labeled RGCs and optic nerves of Sprague-Dawley rats by injecting 20g/L fluorogold (FG) into bilateral superior colliculi. Twenty-four hours after the injection, the right eyes were performed physiological saline anterior chamber perfusion with intraocular pressure maintained at 100mmHg for 60 minutes, while the contralateral eyes were performed sham procedure as control group without elevation of the saline bottle. Retinal hematoxylin and eosin (HE) sections, retinal whole mounts and frozen sections were made 14 days later to observe the morphology and survival of RGCs. Frozen sections and transmission electron microscopy were utilized to investigate the histological manifestations of optic nerves at the same time. RESULTS: A larger number of RGCs presented in control group. It had an average density of 1995±125/mm(2) and distributed uniformly, while RGCs in OHT eyes reduced significantly to 1505±43/mm(2) compared with control group (P<0.05). The optic nerves in control group showed stronger and more uniform fluorescence on the frozen sections, and the auxiliary fibers as well as myelin sheaths were in even and intact organization by transmission electron microscopy. However, exiguous fluorescence signals, vesicular dissociation and disintegration of myelin sheaths were found in OHT group. CONCLUSION: The present study suggested that fluorogold retrograde tracing is a feasible, convenient method for quantitative and qualitative study of neuronal populations and axonal injury in acute ocular hypertension rats.

Prevention of filtering surgery failure by subconjunctival injection of a novel peptide hydrogel into rabbit eyes.

A novel biocompatible hydrogel was prepared based on the supramolecular self-assembly of a peptide containing a bioactive RGD (arginine-glycine-aspartic acid) sequence and a hydrophobic N-fluorenyl-9-methoxycarbonyl (FMOC) tail. When the self-assembled peptide hydrogel was administered after the filtering surgery of rabbit eyes, the level of connective tissue growth factor (CTGF) mRNA as well as the mean intraocular pressure (IOP) was significantly lower than that of the control eyes during the 21 postoperative days. The filtration bleb and ultrasound biomicroscopy (UBM) images showed that a patent bleb and a filtration fistula could be found in the surgical site of a rabbit eye during the whole experimental period. Histological analysis further evidenced that the filtering surgical wound healing was a normal healing process without scar formation. This new approach, making use of a self-assembled peptide hydrogel to normalize filtering surgical wound healing, may have potential for glaucoma filtering surgery.

Evaluation of the biocompatibility of novel peptide hydrogel in rabbit eye.

A peptide containing a RGD (arginine-glycine-aspartic acid) sequence as well as a hydrophobic N-fluorenyl-9-methoxycarbonyl (FMOC) tail was prepared via a standard FMOC solid-phase peptide synthesis technique. The supramolecular self-assembly of such peptide through pi-pi stacking from FMOC tail can transfer the peptide aqueous solution into a three-dimensional hydrogel. The biocompatibility of the peptide hydrogel was evaluated via clinical follow-up and histological analysis. The data obtained demonstrated that the peptide hydrogel exhibited good biocompatibility when injected to the subconjunctival space and anterior chamber of rabbit, indicating a potential application in ophthalmology as an implantable drug delivery system for the treatment to ocular anterior segment diseases such as glaucoma, iridocyclitis, and keratopathy.

Peptide hydrogel as an intraocular drug delivery system for inhibition of postoperative scarring formation.

A biocompatible hydrogel self-assembled from a peptide comprised of a peptide backbone containing Arg-Gly-Asp (RGD) sequence and a hydrophobic N-fluorenyl-9-methoxycarbonyl (FMOC) tail was designed and prepared to load antiproliferative model drug (5-fluorouracil, 5-Fu). After administering this 5-Fu-loaded peptide hydrogel in the filtering surgery of rabbit eyes, because of the sustained release of 5-Fu from the hydrogel to inhibit the scleral flap fibrosis efficiently, the pathology and immunohistochemistry demonstrate that the filtration fistula is patent without postoperative scarring formation, resulting in the significantly low intraocular pressure (IOP) of the rabbit eyes within postoperative 28 days. In a comparison with the conventional 5-Fu exposure, the strategy demonstrated here presents several advantages including providing convenience and preventing the toxicity of 5-Fu to the surrounding ocular tissues efficiently, suggesting a feasibility of this peptide hydrogel as a potential implanted drug delivery system for the inhibition of postoperative scarring formation.