Long-term PM2.5 exposure disrupts corneal epithelial homeostasis by impairing limbal stem/progenitor cells in humans and rat models.

BACKGROUND: Limbal stem/progenitor cells (LSPCs) play a crucial role in maintaining corneal health by regulating epithelial homeostasis. Although PM2.5 is associated with the occurrence of several corneal diseases, its effects on LSPCs are not clearly understood. METHODS: In this study, we explored the correlation between PM2.5 exposure and human limbal epithelial thickness measured by Fourier-domain Optical Coherence Tomography in the ophthalmologic clinic. Long- and short-term PM2.5 exposed-rat models were established to investigate the changes in LSPCs and the associated mechanisms. RESULTS: We found that people living in regions with higher PM2.5 concentrations had thinner limbal epithelium, indicating the loss of LSPCs. In rat models, long-term PM2.5 exposure impairs LSPCs renewal and differentiation, manifesting as corneal epithelial defects and thinner epithelium in the cornea and limbus. However, LSPCs were activated in short-term PM2.5-exposed rat models. RNA sequencing implied that the circadian rhythm in LSPCs was perturbed during PM2.5 exposure. The mRNA level of circadian genes including Per1, Per2, Per3, and Rev-erbα was upregulated in both short- and long-term models, suggesting circadian rhythm was involved in the activation and dysregulation of LSPCs at different stages. PM2.5 also disturbed the limbal microenvironment as evidenced by changes in corneal subbasal nerve fiber density, vascular density and permeability, and immune cell infiltration, which further resulted in the circadian mismatches and dysfunction of LSPCs. CONCLUSION: This study systematically demonstrates that PM2.5 impairs LSPCs and their microenvironment. Moreover, we show that circadian misalignment of LSPCs may be a new mechanism by which PM2.5 induces corneal diseases. Therapeutic options that target circadian rhythm may be viable options for improving LSPC functions and alleviating various PM2.5-associated corneal diseases.

Investigation of the Role of Carcinoembryonic Antigen-Related Cell Adhesion Molecule-1 in Diabetic Retinopathy.

PURPOSE: Diabetic retinopathy (DR) has become a major cause of blindness with increased prevalence of diabetic mellitus. Carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) plays a part in pathological neovascularization. This study aimed to investigate the role of CEACAM1 in the progression of DR. METHODS: Aqueous and vitreous samples were collected from proliferative or non-proliferative DR and the control group. Multiplex fluorescent bead-based immunoassays were used to detect the levels of Cytokines. Expression of CEACAM1, VEGF, VEGF receptor 2 (VEGFR2) and hypoxia-induced factor-1α (HIF-1α) were detected in human retinal microvascular endothelial cells (HRECs). RESULTS: CEACAM1 and VEGF levels were significantly upregulated in PDR group and positively correlated with PDR progression. Expression CEACAM1 and VEGFR2 were increased in HRECs under hypoxic conditions. The HIF-1α/VEGFA/VEGFR2 pathway was blocked by CEACAM1 siRNA in vitro. CONCLUSIONS: CEACAM1 might play a role in the pathology of PDR. CEACAM1 might be a therapeutic target for retinal neovasculariztion.

Recent Advances of Intraocular Lens Materials and Surface Modification in Cataract Surgery.

Advances in cataract surgery have increased the demand for intraocular lens (IOL) materials. At present, the progress of IOL materials mainly contains further improving biocompatibility, providing better visual quality and adjustable ability, reducing surgical incision, as well as dealing with complications such as posterior capsular opacification (PCO) and ophthalmitis. The purpose of this review is to describe the research progress of relevant IOL materials classified according to different clinical purposes. The innovation of IOL materials is often based on the common IOL materials on the market, such as silicon and acrylate. Special properties and functions are obtained by adding extra polymers or surface modification. Most of these studies have not yet been commercialized, which requires a large number of clinical trials. But they provide valuable thoughts for the optimization of the IOL function.

Exosomes-loaded thermosensitive hydrogels for corneal epithelium and stroma regeneration.

Corneal damage forms scar tissue and manifests as permanent corneal opacity, which is the main cause of visual impairment caused by corneal diseases. To treat these diseases, herein, we developed a novel approach based on the exosome derived from induced pluripotent stem cell-derived mesenchymal stem cells (iPSC-MSCs) combined with a thermosensitive hydrogel, which reduces scar formation and accelerates the healing process. We found that a thermosensitive chitosan-based hydrogels (CHI hydrogel) sustained-release iPSC-MSC exosomes can effectively promote the repair of damaged corneal epithelium and stromal layer, downregulating mRNA expression coding for the three most enriched collagens (collagen type I alpha 1, collagen type V alpha 1 and collagen type V alpha 2) in corneal stroma and reducing scar formation in vivo. Furthermore, iPSC-MSCs secrete exosomes that contain miR-432-5p, which suppresses translocation-associated membrane protein 2 (TRAM2), a vital modulator of the collagen biosynthesis in the corneal stromal stem cells to avert the deposition of extracellular matrix (ECM). Our findings indicate that iPSC-MSCs secrete miRNA-containing exosomes to promote corneal epithelium and stroma regeneration, and that miR-432-5p can prevent ECM deposition via a mechanism most probably linked to direct repression of its target gene TRAM2. Overall, our exosomes-based thermosensitive CHI hydrogel, is a promising technology for clinical therapy of various corneal diseases.

Modeling congenital cataract in vitro using patient-specific induced pluripotent stem cells.

Congenital cataracts are the leading cause of childhood blindness. To date, surgical removal of cataracts is the only established treatment, but surgery is associated with multiple complications, which often lead to visual impairment. Therefore, mechanistic studies and drug-candidate screening have been intrigued by the aims of developing novel therapeutic strategies. However, these studies have been hampered by a lack of an appropriate human-disease model of congenital cataracts. Herein, we report the establishment of a human congenital cataract in vitro model through differentiation of patient-specific induced pluripotent stem cells (iPSCs) into regenerated lenses. The regenerated lenses derived from patient-specific iPSCs with known causative mutations of congenital cataracts (CRYBB2 [p. P24T] and CRYGD [p. Q155X]) showed obvious opacification that closely resembled that seen in patients' cataracts in terms of opacification severity and disease course accordingly, as compared with lentoid bodies (LBs) derived from healthy individuals. Increased protein aggregation and decreased protein solubility corresponding to the patients' cataract severity were observed in the patient-specific LBs and were attenuated by lanosterol treatment. Taken together, the in vitro model described herein, which recapitulates patient-specific clinical manifestations of congenital cataracts and protein aggregation in patient-specific LBs, provides a robust system for research on the pathological mechanisms of cataracts and screening of drug candidates for cataract treatment.

Effect of SMILE-derived decellularized lenticules as an adhesion barrier in a rabbit model of glaucoma filtration surgery.

BACKGROUND: To investigate the effects of small incision lenticule extraction (SMILE)-derived decellularized lenticules on intraocular pressure (IOP) and conjunctival scarring in a rabbit model of glaucoma filtration surgery. METHODS: Trabeculectomy was performed on both eyes of New Zealand rabbits. A decellularized lenticule was placed in the subconjunctival space in one eye of the rabbits (the decellularized lenticule group), and no adjunctive treatment was performed in the fellow eye (the control group). The filtering bleb features and IOP were evaluated 0, 3, 7, 14, 21, and 28 days after surgery, and histopathologic examination was performed 28 days after surgery. RESULTS: Decellularized lenticules significantly increased bleb survival and decreased IOP postoperatively in the rabbit model with no adverse side effects. The histopathologic results showed a larger subconjunctival space and less subconjunctival fibrosis in the decellularized lenticule group. CONCLUSIONS: Decellularized lenticules can prevent postoperative conjunctiva-sclera adhesion and fibrosis, and they may represent a novel antifibrotic agent for trabeculectomy.

Evaluation of the Difference between Predicted and Measured Central Corneal Thickness Reduction after SMILE and Femtosecond Laser-assisted LASIK for Myopia.

PURPOSE: To evaluate the agreement between the predicted and measured central corneal thickness (CCT) reduction after the small incision lenticule extraction (SMILE) surgery and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) surgery. METHODS: A total 165 patients were enrolled in this prospective study. Eighty patients with a mean spherical equivalent (SE) of -4.72 ± 1.80 Diopters (D) were treated with the FS-LASIK procedure and Eighty-five patients with a mean SE of -4.78 ± 1.63 D were treated with SMILE procedure. One eye for each patient was randomly selected and included for statistical analysis. Ultrasound pachymetry measurement and Scheimpflug camera corneal topography were performed preoperatively and 3 months postoperatively. The measured CCT reduction was calculated by comparing the preoperative examinations with postoperative examinations. Comparative statistics and linear regression analyses were performed. RESULTS: The mean predicted CCT reduction was 95.02 ± 21.39 µm in FS-LASIK group and 103.49 ± 22.87 µm in SMILE group (P = .015). The prediction of laser platform was found to overestimate the measured CCT reduction for both FS-LASIK group (ultrasound 13.20 ± 9.34 µm) and SMILE group (ultrasound 13.12 ± 8.68 µm). The prediction of laser platform was found to systematically overestimate the measured CCT reduction in FS-LASIK group. In SMILE group, the difference between predicted and measured CCT reduction were found significantly related with the predicted CCT reduction (P < .001 for ultrasound; and P = .004 for Pentacam). CONCLUSION: A systematic overestimation of measured CCT reduction in FS-LASIK group did not influence the refractive precision of FS-LASIK. Due to the different biomechanical distributions in post-SMILE cornea, the measured CCT reduction was influenced as the changes in refractive correction. Nomogram adjustment for high myopic correction needs further research.

Case Report: Self-Resolved Macular Edema Secondary to Congenital Retinal Macrovessels.

PURPOSE: To report a case of macular edema secondary to congenital retinal macrovessels (CRMs), which resolved spontaneously without any treatment. OBSERVATIONS: A 39-year-old female presented with blurry vision of the right eye for one day. Fundus examination revealed a branch of artery and vein of the inferior retinal arcade crossing the horizontal raphe. Optical coherence tomography (OCT) through the fovea showed cystoid macular edema in the outer plexiform layer. However, no leakage of the vessels was noticed by fundus fluorescein angiography (FFA). Observation was recommended with close follow-up. Two weeks later, the patient returned with good visual acuity, and the macular edema was resolved spontaneously. CONCLUSIONS: Macular edema is a possible complication of CRM by increasing retinal capillary hydrostatic pressure. Treatment is not necessary for this kind of macular edema if no leakage of the vessels is noticed on FFA.

Enhancement of lens extraction-induced MCP-1 upregulation and microglia response in long-term diabetes via c-jun, stat1 and ERK.

AIM: Diabetic patients are reported to have a higher incidence of cataract surgery-induced retinal complications, possibly due to retinal inflammation. Our goal is to identify the key inflammatory cytokines, cells and regulatory pathways involved. MAIN METHODS: Diabetes mellitus (DM) induced by streptozotocin and control mice received extracapsular lens extraction (ECLE) in one eye. Neuroretinas were collected at postoperative day1(P1), day2(P2), and day7(P7). BV2 cells were harvested under the treatment of high glucose, lipopolysaccharide (LPS) and inhibitors. The method of qPCR, western blot and immunohistochemistry were used to identify the expression of cytokines and signaling pathways. KEY FINDINGS: ECLE induced increased inflammation in the neuroretina of surgery eye with a peak at P1. MCP-1 surge in long-term diabetes mellitus (LDM) mice at P1 is higher than short-term diabetes mellitus (SDM) mice and normal mice. Significant activation of c-jun and c-fos were found in LDM compared to normal and SDM. Advanced activation of stat1 and ERK was found at P1 in LDM instead of at P2 in SDM and Normal. Activation of microglia/macrophage was also detected in the LDM mice. Besides the inhibition of c-jun/JNK, MCP-1 expression can be attenuated by inhibiting stat1 and ERK under high glucose condition after LPS stimulation. SIGNIFICANCE: Enhancement of lens extraction-induced MCP-1 upregulation and microglia response in long-term diabetes might be due to the activation of cjun, stat1 and ERK, which provided potential therapeutic targets to attenuate retinal inflammation after surgery in diabetic individuals.

Transcriptomic profiling of human corneal epithelial cells exposed to airborne fine particulate matter (PM2.5).

PURPOSE: To explore the molecular mechanisms of PM2.5-induced dysfunction in human corneal epithelial cells (HCECs) and the potential role of the plasminogen activator inhibitor type-2 (PAI-2) in PM2.5-induced autophagy in vitro and in vivo. METHODS: RNA-Seq was performed to identify the differentially expressed genes (DEGs) in PM2.5-exposed HCECs compared to unexposed condition, followed by validation via real-time PCR (qRT-PCR). Corneal fluorescein staining and tear secretion were assessed in the PM2.5-exposed rat model. The expression of PAI-2 and autophagy-related markers were examined via immunoblotting, immunofluorescence staining and/or qRT-PCR in PM2.5-exposed or unexposed HCECs and rat corneas. PAI-2-knockdown HCECs were generated to study PAI-2's role in the PM2.5-induced autophagy in HCECs. RESULTS: A total of 434 DEGs-240 up-regulated and 194 down-regulated-were identified in PM2.5-exposed HCECs rather than unexposed HCECs. The expression of a few genes related to proliferation, inflammation, and aryl hydrocarbon stimulation were significantly altered by PM2.5 exposure. PAI-2 expression was up-regulated in PM2.5-exposed HCECs, sharing a similar fluctuation trend with autophagy-related markers LC3B II and BECN1 according to various exposure periods. Moreover, PAI-2 knockdown significantly suppressed the expression of LC3B and BECN1 in PM2.5-exposed HCECs. The corneal fluorescein staining was enhanced and tear secretion was significantly reduced in PM2.5-exposed rat eyes. PAI-2 expression was also increased in PM2.5-exposed rat corneas, together with the up-regulation of several autophagy-related markers. CONCLUSION: The present study identified the altered expression of hundreds of genes in PM2.5-exposed HCECs, which suggests the importance of PM2.5 for cornea health. The involvement of PAI-2 was discovered in the PM2.5-induced autophagy in HCECs as well as likely in rat corneas, which implied that PAI-2 may become a potential target of clinical treatment of PM2.5-associated ocular surface diseases.

Investigation of predictability and influence factors of the achieved lenticule thickness in small incision lenticule extraction.

BACKGROUND: To evaluate the differences between the predicted and achieved lenticule thickness (ΔLT) after small incision lenticule extraction (SMILE) surgery and investigate relationships between ΔLT and predicted lenticule thickness in SMILE. METHODS: A total of 184 eyes from 184 consecutive patients who underwent SMILE were included in this prospective study. One eye for each patient was randomly selected and included for statistical analysis. To achieve emmetropia, nomogram adds 10% correction of spherical refractive. An ultrasound pachymetry measurement and Scheimpflug camera corneal topography were obtained before and at 3 months after SMILE. The achieved lenticule thickness was calculated by comparing the preoperative examinations with postoperative examinations using ultrasound pachymetry and Pentacam software measurements. The pupil center and corneal vertex were selected as the 2 locations for measurement calculation on Pentacam. Analysis of variance (ANOVA) was performed to compare mean pachymetry values using different instruments. Linear regression analyses were performed between the VisuMax readout lenticule thicknesses and the measured maximum corneal change, between ΔLT and predicted lenticule thickness. RESULTS: On average, the achieved lenticule thickness measured with ultrasound pachymetry was 13.02 ± 8.87 µm thinner than the predicted lenticule thickness. The proportion of ΔLT in predicted values is 11.9% (ultrasound) and about 15% (Pentacam). Linear regression analysis showed significant relationships between the predicted and each achieved lenticule thickness. Each ΔLT was significantly related to predicted lenticule thickness (ultrasound: R2 = 0.242; pupil center from Pentacam: R2 = 0.230). CONCLUSIONS: An overestimation of achieved lenticule thickness was evident in this study which may exclude eligible SMILE patient. Also, our results showed that 10% increase of spherical refractive correction in the nomogram is appropriate. Furthermore, clinicians should subtract 10% of the predicted lenticule thickness to calculate the residual corneal stroma bed thickness.

KRT8 phosphorylation regulates the epithelial-mesenchymal transition in retinal pigment epithelial cells through autophagy modulation.

Proliferative vitreoretinopathy (PVR) is a severe ocular disease which results in complex retinal detachment and irreversible vision loss. The epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells is considered to be critical in the pathogenesis of PVR. In this study, we focused on the potential impact of keratin 8 (KRT8) phosphorylation and autophagy on TGF-ß2-induced EMT of RPE cells and explored the relationship between them. Using immunofluorescence and Western blot analysis, the co-localization of KRT8 and autophagy marker, as well as the abundance of phosphorylated KRT8 (p-KRT8) expression, was observed within subretinal and epiretinal membranes from PVR patients. Moreover, during TGF-ß2-induced EMT process, we found that p-KRT8 was enhanced in RPE cells, which accompanied by an increase in autophagic flux. Inhibition of autophagy with pharmacological inhibitors or specific siRNAs was associated with a reduction in cell migration and the synthesis of several EMT markers. In the meantime, we demonstrated that p-KRT8 was correlated with the autophagy progression during the EMT of RPE cells. Knockdown the expression or mutagenesis of the critical phosphorylated site of KRT8 would induce autophagy impairment, through affecting the fusion of autophagosomes and lysosomes. Therefore, this study may provide a new insight into the pathogenesis of PVR and suggests the potential therapeutic value of p-KRT8 in the prevention and treatment of PVR.

Multiple cytokine analyses of aqueous humor from the patients with retinitis pigmentosa.

PURPOSE: Cataracts are the most common eye complications of retinitis pigmentosa (RP). This study aimed to investigate the cytokine profiles of the aqueous humor of RP with cataracts. METHODS: The aqueous humor was collected from RP eyes with cataract (RP group, n = 20) and age-related cataract eyes (ARC group, n = 20) during cataract surgery. The levels of 37 mediators were measured with multiplex fluorescent bead-based immunoassay and compared across groups. The correlation among chemokines, growth factors, and cytokines was analyzed with Spearman's rank correlation coefficient. RESULTS: Twelve cytokines (IL-1α, IL-1ß, IL-4, IL-10, TNF-α, IFN-γ, EGF, GM-CSF, PDGF-AB/BB, TGF-α, BMP-9, and E-selection) were below the limit of detection, and the detection rate of IL-6 was significantly higher in RP group than in the ARC group (P < 0.01). Compared with those in the control group, the aqueous humor levels of monocyte chemoattractant protein-1 (MCP-1), interleukin-(IL-)8, interferon gamma-induced protein (IP)-10, hepatocyte growth factor (HGF), platelet-derived growth factor AA (PDGF-AA), matrix metalloproteinase-2 (MMP-2), MMP3, MMP-7, MMP-8, plasminogen activator inhibitor-1 (PAI-1), and thrombospondin-2 (TSP-2) in the RP group increased significantly (P < 0.01). A lower level of BMP-4 in the aqueous humor was observed in the RP patients than in the controls (P < 0.05). CONCLUSIONS: Significantly increased levels of PDGF-AA, MMP2, MMP3, MMP-7, MMP-8, PAI-1, and TSP-2 and lower levels of BMP-4 were found in the aqueous humor of RP patients. This result indicates a disturbance of the extracellular matrix (ECM) and cytokines in RP patients and suggests a possible role of these cytokines in the pathogenesis of capsular contraction syndrome (CCS) in RP patients.

Comparative study of anterior segment measurements using 3 different instruments in myopic patients after ICL implantation.

BACKGROUND: To compare and correlate anterior segment measurements of myopic eyes implanted with Implantable Collamer lens (ICL V4c) by using anterior segment optical coherence tomography (AS-OCT), Pentacam and ultrasound biomicroscopy (UBM). METHODS: Anterior chamber depth (ACD), distance between corneal endothelium and anterior surface of ICL(C-ICL) and central vault were measured in 82 phakic myopic eyes of 82 patients who underwent ICL surgery, by using AS-OCT, Pentacam and UBM consecutively at 3 months follow up. The correlation and agreement of instruments were accessed by using Intraclass correlation coefficient (ICC) and the Bland-Altman plot. RESULTS: AS-OCT showed higher ACD, C -ICL and central vault measurements than both of Pentacam and UBM (P < 0.001), while Pentacam showed lower measurements than UBM (P < 0.05). The Pearson correlation coefficient (r) was 0.91 to 0.96, and ICC was 0.95 to 0.98 for all measurements between difference devices (all P < 0.001). The 95% limits of agreement of ACD, C-ICL, vault measurements were 0.13 to 0.38 mm, - 0.07 to 0.27 mm, 0.08 to 0.34 mm between AS-OCT and Pentacam, - 0.03 to 0.33 mm, - 0.16 to 0.31 mm, - 0.10 to 0.26 mm between AS-OCT and UBM, and - 0.29 to 0.07 mm, - 0.25 to 0.20 mm, - 0.31 to 0.05 mm between Pentacam and UBM, respectively. CONCLUSIONS: AS-OCT demonstrated significantly higher value, while Pentacam demonstrated significantly lower value than UBM for ACD, C-ICL and central vault measurements in myopic eyes after ICL surgery. Measurements with these instruments were highly correlated, but could not replace each other especially for vault. This study provided valuable information about how to judge the results of anterior segment parameters of eyes implanted with ICL V4c from different devices. TRIAL REGISTRATION: Registration number: ChiCTR-OOC-16008987 . Retrospectively registered: 08 August 2016.

Opacification of lentoid bodies derived from human induced pluripotent stem cells is accelerated by hydrogen peroxide and involves protein aggregation.

Despite the recent breakthrough in cataract drug development, further improvements have been limited by the lack of human in vitro cataract disease models. This study, therefore, aims to generate a qualified cataract disease model. Mature lentoid bodies (LBs) on Day 25 (D25), which were differentiated from human induced pluripotent stem cells (iPSCs) using the "fried egg" method, were continually culturing (control) or extra treated with either ultraviolet (UV) radiation or hydrogen peroxide (H2 O2 ). The LBs' shape alteration and opacity were examined using light microscopy and mean gray value evaluation. Their structure and crystallin expression were examined using immunofluorescence and transmission electron microscopy (TEM). Real-time polymerase chain reaction and western blot were used to investigate the potential role of autophagy in cloudy LBs. Mature LBs became cloudy with time which was accelerated by H2 O2 . Immunofluorescence examinations and TEM showed that the H2 O2 -treated and control LBs had similar shapes, lens capsule, and monolayer lens epithelial cell (LEC) structures. However, we were unable to do further assessment of the UV-treated LBs as the structures of LBs were easily damaged when treated with UV radiation. Cells containing aggregated protein (αA-crystallin and αB-crystallin) puncta were more abundant in the H2 O2 -treated LBs as compared with control LBs. Moreover, LC3B expression decreased with age in anterior lens capsules obtained from age-related cataracts (ARCs) patients as compared with LC3B levels in primary LECs, which is consistent with that LC3B expression in LBs was lower on D45 than on D25. Our study found that human iPSCs-derived LBs became cloudy with time which was accompanied by protein aggregation, and this phenomenon was accelerated by H2 O2 , suggesting that LBs with extending culture may serve as a human model for in vitro ARCs.

Contralateral Eye Comparison Between 2 Cap Thicknesses in Small Incision Lenticule Extraction: 110 Versus 130 µm.

PURPOSE: To evaluate the posterior corneal elevation (PCE) and biomechanical changes after small incision lenticule extraction (SMILE) at depths of 110 µm and 130 µm. METHODS: One hundred sixteen eyes from 58 consecutive patients who underwent SMILE were included in this prospective study. Each patient underwent SMILE in one eye to a depth of 110 µm and in the other eye to a depth of 130 µm. A Scheimpflug camera and Hartmann-Shack WASCA aberrometer were used to assess the PCE and wavefront aberrations, respectively, before SMILE and at 1 and 3 months after surgery. The PCE was analyzed along 3 optical zones (apex and 2 and 4 mm diameters) as a function of the meridian. Dynamic Scheimpflug imaging was used to evaluate the biomechanics preoperatively and at 1 day, 1 month, and 3 months postoperatively. RESULTS: No significant difference was found in either vision correction or corneal biomechanics between the 2 groups. In both groups, the PCE became significantly flattened at the apex and at 2 mm annulus 1 month postoperatively, especially for the 110-µm cap group. Three months postoperatively, the 110-µm cap group was still flattened significantly, whereas the displacement at the apex in the 130-µm cap group had disappeared. There was no significant difference in wavefront aberrations between the groups after surgery, except in the vertical coma (P < 0.001). CONCLUSIONS: The differences in corneal biomechanics between the 110-µm cap group and 130-µm cap group were small; however, the superficial lenticule might cause displacement of the PCE to be more persistent in one eye than in the other.

Pterygium surgery combined with the removal of a missed occult iris foreign body detected incidentally during pterygium examination: a case report.

BACKGROUND: An occult foreign body may be retained in patient with small self-sealing wound and no decreased visual acuity without complete examination. Here we report a case of a retained occult ferrous iris foreign body detected incidentally during pterygium examination. CASE PRESENTATION: A 69-year-old man presented to our ophthalmology department because of foreign body sensation and persistent redness in both eyes for 2 years. In the left eye, a pterygium, paracentral corneal opacity and a vertically oval pupil were observed. Ultrasound biomicroscopy and gonioscopy revealed a retained metallic-like foreign body partially embedded in the inferior peripheral iris. Pterygium surgery and the removal of the retained iris foreign body were performed simultaneously. No recurrent pterygium or residual foreign body was found during follow-up. CONCLUSIONS: A thorough history should be obtained and complete physical examination should be performed in patients with ocular self-sealing wounds to prevent missed intraocular foreign bodies, which may result in potential sight-threatening ocular complications.

Thermosensitive chitosan-based hydrogels releasing stromal cell derived factor-1 alpha recruit MSC for corneal epithelium regeneration.

Corneal epithelium integrity depends on continuous self-renewing of epithelium and connections between adjacent cells or between the cells and the basement membrane. Self-renewing epithelium cells mainly arise from the continuous proliferation and differentiation of the basal layer and limbal stem cells. The aim of the present study was to generate a bioactive, thermosensitive chitosan-gelatin hydrogel (CHI hydrogel) by incorporating exogenous recombinant human stromal cell-derived factor-1 alpha (SDF-1 alpha) for corneal epithelium regeneration. The exogenous SDF-1 alpha could enhance the stem cells proliferation, chemotaxis and migration, and the expression levels of related genes were significantly elevated in LESCs and mesenchymal stem cells (MSCs) in vitro. Moreover, the MSCs promoted the proliferation and maintained the corneal fate of the LESCs. The rat alkali injury model was used for in vivo study. The injured eyes were covered with CHI hydrogel alone or rhSDF-1 alpha-loaded CHI hydrogel. All rats were followed for 13days. Histological examination showed that the SDF-1 alpha/CHI hydrogel complex group had a nearly normal thickness; moreover, it was also found that this group could upregulate the expression of some genes and had more ΔNp63-positive cells. The SDF-1 alpha/CHI hydrogel complex group had a more tightly arranged epithelium compared with the control group using transmission electron microscopy (TEM). The mechanism for this may have involved the activation of stem cell homing and the secretion of growth factors via the SDF-1/CXCR4 chemokine axis. Therefore, SDF-1 alpha/CHI hydrogel complexes could provide a new idea for the clinical application. STATEMENT OF SIGNIFICANCE: The clarity of cornea is important for normal vision. The loss or dysfunction of LESCs leads to the impairment of corneal epithelium. The complete regeneration of corneal epithelium has not been achieved. Our study demonstrated that the incorporation of rhSDF-1 alpha with CHI hydrogel accelerated corneal epithelium reconstruction with more native structural and functional properties. The mechanism may involve in inducing proliferation and migration of the LESCs and MSCs to the injury site via the SDF-1/CXCR4 chemokine axis. Therefore, SDF-1 alpha/CHI hydrogel complexes could be a practical application for clinical therapy.

Airborne particulate matter (PM2.5) triggers autophagy in human corneal epithelial cell line.

PURPOSE: To investigate particulate matter (PM2.5)-induced damage to human corneal epithelial cells (HCECs) and to determine the underlying mechanisms. METHODS: HCECs were exposed to PM2.5 at a series of concentrations for various periods. Cell viability was measured by using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell proliferation was evaluated via 5-ethynyl-2'-deoxyuridine (EdU) analysis, while autophagy was determined by immunofluorescence and Western blot. RESULTS: PM2.5-induced cell damage of HCECs occurred in a time- and dose-dependent manner. Decreased cell viability and proliferation as well as increased apoptosis were observed in HCECs after PM2.5 exposure for 24 h. Autophagy in HCECs was slightly inhibited in the early stage (before 4 h) of exposure but significantly activated in the late stage (after 24 h), as evidenced by a decrease in the former and increase in the latter of the expression of the autophagy-associated markers LC3B, ATG5, and BECN1. Interestingly, rapamycin, an autophagy activator, attenuated early-stage but aggravated late-stage PM2.5-induced cell damage, suggesting that the role of autophagy in HCECs may change over time during PM2.5 exposure. In addition, in the early stage, the expression of LC3B and ATG5 increased in cells co-treated with rapamycin and PM2.5 compared to rapamycin-only or PM2.5-only treated cells, suggesting that autophagy may benefit cell viability after PM2.5 exposure. CONCLUSIONS: The results indicate the potential role of autophagy in the treatment of PM2.5-induced ocular corneal diseases and provide direct evidence for the cytotoxicity, possibly involving an autophagic process, of PM2.5 in HCECs.

Proliferative Effects of Histamine on Primary Human Pterygium Fibroblasts.

Purpose. It has been confirmed that inflammatory cytokines are involved in the progression of pterygium. Histamine can enhance proliferation and migration of many cells. Therefore, we intend to investigate the proliferative and migratory effects of histamine on primary culture of human pterygium fibroblasts (HPFs). Methods. Pterygium and conjunctiva samples were obtained from surgery, and toluidine blue staining was used to identify mast cells. 3-[4, 5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) was performed to evaluate the proliferative rate of HPFs and human conjunctival fibroblasts (HCFs); ki67 expression was also measured by immunofluorescence analysis. Histamine receptor-1 (H1R) antagonist (Diphenhydramine Hydrochloride) and histamine receptor-2 (H2R) antagonist (Nizatidine) were added to figure out which receptor was involved. Wound healing model was used to evaluate the migratory ability of HPFs. Results. The numbers of total mast cells and degranulated mast cells were both higher in pterygium than in conjunctiva. Histamine had a proliferative effect on both HPFs and HCFs, the effective concentration (10 µmol/L) on HPFs was lower than on HCFs (100 µmol/L), and the effect could be blocked by H1R antagonist. Histamine showed no migratory effect on HPFs. Conclusion. Histamine may play an important role in the proliferation of HPFs and act through H1R.