Zuguo Liu

Fudan University, Shanghai, Shanghai Shi, China

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Publications (65)158.33 Total impact

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    ABSTRACT: Dry eye is a multifactorial disease of the tears and the ocular surface. This study aimed to investigate the clinical efficacy of a non-steroidal anti-inflammatory drug, pranoprofen, in the treatment of dry eye.
    Chinese medical journal. 07/2014; 127(13):2407-12.
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    ABSTRACT: A 56-year-old woman with a history of disposable soft contact lens wear was referred to our university eye center for a corneal ulcer. Based on the microbial culture, the initial diagnosis was bacterial keratitis, which was unresponsive to topical fortified antibiotics. The patient was then examined using in vivo confocal microscopy, which revealed Acanthamoeba infection. This case emphasizes the need to suspect Acanthamoeba infection in soft contact lens wearers who present with progressive ulcerative keratitis or progressively worsening corneal ulcers that are not responsive to the usual antimicrobial therapy. It is also important to consider the possibility of a coinfection with bacterial and Acanthamoeba species.Virtual Slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5168343391150859.
    Diagnostic pathology. 06/2014; 9(1):105.
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    ABSTRACT: Benzalkonium chloride (BAC) is the most commonly used preservative in ophthalmic preparations.So far large bodies of clinical and experimental studies have shown that use of topical drugs containing BAC can induce a series of ocular surface diseases, such as apoptosis.However, recently, some clinical studies have shown that ocular toxicity in patients treated with eye drops containing BAC has not apparent correlated with BAC.Some scholars consider that the limitations of the research lead people to recognize the BAC toxicity exaggeratedly.Here we summarize numerous clinical and experimental studies of BAC in the past few years, and focus on reviewing recent researches of the toxic effect of BAC on ocular surface.
    [Zhonghua yan ke za zhi] Chinese journal of ophthalmology 04/2014; 50(4):303-6.
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    ABSTRACT: To determine the vision-related quality of life (VR-QOL) in patients with infectious keratitis using the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25). Sixty-five patients with infectious keratitis (IK) were enrolled in the study. The NEI VFQ-25 scores and clinical and demographic data, including age, gender, pathogen, best corrected visual acuity (BCVA), and duration of the disease, were collected from the subjects. The subscale and composite scores were calculated and analyzed. Correlations between the VFQ-25 scores and the clinical and demographic features were also explored. The mean age of enrolled subjects was 48.4 years (SD, 16.2), with 44 males (67.7%). The microbial pathogens were viruses (n = 48, 73.8%), fungi (n = 13, 20.0%), and bacteria (n = 4, 6.2%). The mean scores of each VFQ-25 subscale ranged from 31.9 (SD, 28.6) for role difficulties to 92.7 (SD, 13.1) for color vision; the mean composite score was 58.1 (SD, 19.2). Significant differences in scores were observed only in the subscale of dependency among educational levels and in the mental health subscale and the composite among the three pathogen groups. Multivariate regression analysis revealed that VFQ-25 composite score correlated significantly with the BCVA of the worse-seeing eye, duration of the disease, history of operation (for IK treatment), and gender. Infectious keratitis has extensive impacts on patients and VR-QOL. The BCVA of worse-seeing eye, duration, history of operation for IK treatment, and gender contributed independently to VR-QOL. Early treatment should be encouraged to obtain better visual prognosis and VR-QOL for patients with IK.
    Optometry and vision science: official publication of the American Academy of Optometry 01/2014; · 1.53 Impact Factor
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    ABSTRACT: There are several animal models illustrating dry eye pathophysiology. Current study would like to establish an ex vivo tissue culture model for characterizing dry eye. Human conjunctival explants were cultured under airlift or submerged conditions for up to 2 weeks, and only airlifted conjunctival cultures underwent increased epithelial stratification. Starting on day 4, the suprabasal cells displayed decreased K19 expression whereas K10 keratin became evident in airlift group. Pax6 nuclear expression attenuated already at 2 days, while its perinuclear and cytoplasmic expression gradually increased. MUC5AC and MUC19 expression dramatically decreased whereas the full thickness MUC4 and MUC16 expression pattern disappeared soon after initiating the airlift condition. Real time PCR showed K16, K10 and MUC16 gene up-regulated while K19, MUC5AC, MUC19 and MUC4 down-regulated on day 8 and day 14. On day 2 was the appearance of apoptotic epithelial and stromal cells appeared. The Wnt signaling pathway was transiently activated from day 2 to day 10. The inflammatory mediators IL-1β, TNF-α, and MMP-9 were detected in the conditioned media after 6 to 8 days. In conclusion, airlifted conjunctival tissue cultures demonstrated Wnt signaling pathway activation, coupled with squamous metaplasia, mucin pattern alteration, apoptosis and upregulation of proinflammatory cytokine expression. These changes mimic the pathohistological alterations described in dry eye. This correspondence suggests that insight into the pathophysiology of dry eye may be aided through the use of airlifted conjunctival tissue cultures.
    PLoS ONE 01/2014; 9(1):e87368. · 3.73 Impact Factor
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    ABSTRACT: Prostaglandin (PG) analogs, including latanoprost, travoprost, and bimatoprost, are currently the most commonly used topical ocular hypotensive medications. The purpose of this study was to investigate the corneal alterations in rabbits following exposure to commercial solution of latanoprost, travoprost and bimatoprost. A total of 64 New Zealand albino rabbits were used and four groups of treatments were constituted. Commercial latanoprost, travoprost, bimatoprost or 0.02% benzalkonium chloride (BAK) was applied once daily to one eye each of rabbits for 30 days. The contralateral untreated eyes used as controls. Schirmer test, tear break-up time (BUT), rose Bengal and fluorescein staining were performed on days 5, 10, 20, and 30. Central corneal changes were analyzed by in vivo confocal microscopy, and the corneal barrier function was evaluated by measurement of corneal transepithelial electrical resistance on day 5. Whole mount corneas were analyzed by using fluorescence confocal microscopy for the presence of tight-junction (ZO-1, occludin) and adherens-junction (E-cadherin, β-catenin) proteins, actin cytoskeleton, proliferative marker Ki67 and cell apoptosis in the epithelium. Topical application of commercial PG analogs resulted in significant corneal epithelial and stromal defects while no significant changes in aqueous tear production, BUT, rose bengal and fluorescein staining scores on day 5. Commercial PG analogs induced dislocation of ZO-1 and occludin from their normal locus, disorganization of cortical actin cytoskeleton at the superficial layer, and disruption of epithelial barrier function. The eyes treated with 0.02% BAK and latanoprost exhibited significantly reduced Schirmer scores, BUT, and increased fluorescein staining scores on days 10 and 30, respectively. Topical application of commercial PG analogs can quickly impair the corneal epithelium and stroma without tear deficiency. Commercial PG analogs break down the barrier integrity of corneal epithelium, concomitant with the disruption of cell junction and actin cytoskeleton between superficial cells in the corneal epithelium in vivo.
    PLoS ONE 01/2014; 9(3):e89205. · 3.73 Impact Factor
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    ABSTRACT: To investigate the effects and mechanism of amniotic extraction on corneal healing after photorefractive keratectomy (PRK). Experimental Study. Thirty-six New Zealand rabbit corneas were performed with PRK models (-10 diopters, 6.5 mm diameter). According to random number table, all eyes were divided into three groups, including treated with amniotic extraction, 0.1% dexamethasone and excipient respectively after operation. Clinical and histopathologic examinations were taken by slit-lamp microscope and light microscope. Corneal epithelium reparation was observed by fluorescent staining. Corneal stroma cell apoptosis was evaluated by terminal deoxyribonucleotidy transferase-mediated deoxynuridine triphophate nick end labeling (TUNEL) assay. Myofibroblast generation was evaluated by immunofluorescence checking the expression of alpha-smooth muscle actin (α-SMA). The number of TUNEL and α-SMA positive cells was analyzed to explore the effects on corneal haze. The haze grading was compared between groups using Kruskal-Wallis H test. Mean values for each experiment were compared between groups using a one-way analysis of variance and LSD-t test.Spearman rank analysis was used to evaluate the correlation between the haze grading and the expression of TUNEL positive cells and α-SMA. The corneas of seventy-two eyes reepithelialized in 6 days after operation. The average epithelium repair time of the AE group was (4.12 ± 0.62) d, the dexamethasone group was (5.25 ± 0.78) d, and the excipient group was (4.96 ± 0.73) d. The progression of reepithelialization was significantly faster in the AE group than the other two groups (F = 14.144, P < 0.01). The haze appeared in the first week after the PRK in all three groups, increased after 3-4 weeks, and relieved after 8 weeks. The degree of haze was significantly lower in the AE group than the other two groups in the first week (Vs. dexamethasone group, H = 3.995, P < 0.05; vs. excipient group, H = 12.77, P < 0.01), in the 4th week (Vs. dexamethasone group, H = 4.468, P < 0.05;vs. excipient group, H = 9.003, P < 0.01), and 8th week (Vs dexamethasone group, H = 4.397, P < 0.05;vs. excipient group, H = 5.744, P < 0.05) after PRK. The TUNEL-positive cells appeared in the central anterior stroma at the first week after surgery. And the number of TUNEL-positive cells in the AE group was (2.2500 ± 0.3750) cells/HP, the dexamethasone group was (4.5000 ± 0.7500) cells/HP, and the excipient group was (7.1250 ± 0.9063) cells/HP. The number of TUNEL-positive cells in AE group was less than those in the other two groups (Vs. dexamethasone group, t = 4.26, P < 0.01; vs. excipient group, t = 8.13, P < 0.01). The TUNEL-positive cells were only found in the excipient group (2.8750 ± 0.6563)/HP in 4th week after operation.It was significantly different between the dexamethasone group and the excipient group (t = 9.01, P < 0.01). There were no significant TUNEL-positive cells in 8th weeks in all three groups.α-SMA-positive cells started to appear apparently at the first week after surgery in the dexamethasone and excipient groups, and the peaks appeared at the 4th week after treatments, and there were still a lot of α-SMA-positive cells in corneal stroma at the 8th week after operation in both groups.On the contrary, there were no significant α-SMA-positive cells in the AE group all the time after surgery. The statistical significant difference can be found between the AE group vs. the dexamethasone and excipient groups in the first week (t = 28.62, 36.55;P < 0.01), in the 4th week (t = 30.40, 35.96; P < 0.01), and in the 8th week (t = 34.02, 38.32; P < 0.01).Spearman rank analysis demonstrated that the formation of haze was proportional to the expression of TUNEL positive cells (r = 0.881, P < 0.01) and α-SMA (r = 0.710, P < 0.01). Amniotic extraction can reduce the formation of haze, which was more effective than 0.1% dexamethasone.It might release certain factors which were transported into corneal matrix, then affected the healing of epithelial cell by interacting with the corneal cell factors, reducing the cell apoptosis, corneal wound healing response and rebuilding the corneal matrix with less myofibroblast, collagen and scar and finally reduce the formation of haze.
    [Zhonghua yan ke za zhi] Chinese journal of ophthalmology 01/2014; 50(1):42-50.
  • Ophthalmology 12/2013; 120(12):e86. · 5.56 Impact Factor
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    ABSTRACT: To establish normal noninvasive tear film breakup time (NI-BUT) values in the Chinese population and investigate age-related changes in NI-BUT using a newly developed Keratograph. Forty normal volunteers with a mean age of 32.8 ± 16.7 years were recruited for this study. Clinical and demographic data, including age, gender, fluorescein tear film breakup time (FBUT), and Schirmer I test values were collected from the subjects. Noninvasive tear film breakup time was measured using a new method based on a corneal topographer equipped with a modified scan software. The correlations between the NI-BUT, age, and gender were determined. In total, a significant difference between the NI-BUT and the FBUT was found (4.9 ± 2.4 seconds vs. 9.0 ± 3.0 seconds; p < 0.001). No statistically significant difference in the NI-BUT was observed between the male and female subjects (5.5 ± 2.0 seconds vs. 4.5 ± 2.5 seconds; p = 0.137). In addition, no significant correlation was detected between the NI-BUT and age (0.143, p = 0.321). The NI-BUT values found in this study are much lower than those of previous reports. Our results show no significant differences in tear film stability with age. The tear physiology of the Chinese population may not be the same as in Western populations.
    Optometry and vision science: official publication of the American Academy of Optometry 11/2013; · 1.53 Impact Factor
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    ABSTRACT: Purpose: Endothelial progenitor cells (EPC) have been shown to participate in ischemia-induced retinal neovascularization (NV). Over-activation of Wnt signaling plays a pathogenic role in ischemia-induced retinal NV. The purpose of this study is to determine whether Wnt signaling regulates EPC release. Methods: Oxygen-induced retinopathy (OIR) was used as a model of retinal NV and Wnt pathway activation. EPC, marked as c-Kit+/Tie-2+ cells in the peripheral blood and bone marrow, were quantified using flow cytometry following immunolabeling. Wnt signaling activity was evaluated by measuring non-phosphorylated β-catenin levels and X-gal staining in the Wnt reporter mice (Bat-gal mice). Results: c-Kit+/Tie-2+ cells were significantly increased in both of the peripheral blood and bone marrow of mice with OIR, compared to non-OIR mice. Over-expression of kallistatin, an endogenous inhibitor of the Wnt pathway, in kallistatin transgenic (kallistatin-TG) mice with OIR attenuated the increases of c-Kit+/Tie-2+ cells in the peripheral blood and bone marrow, compared to WT mice with OIR. When the Bat-gal mice were crossed with kallistatin-TG mice, kallistatin over-expression suppressed the OIR-induced increases of X-gal positive cells in the retinas and bone marrow, suggesting inhibition of Wnt signaling in these tissues. Furthermore, intraperitoneal injection of LiCl, a Wnt signaling activator, increased c-Kit+/Tie-2+ cells in the peripheral blood of normal mice. Consistently, LiCl activated Wnt signaling in both of the retina and bone marrow cells in Bat-gal mice. Conclusions: Wnt signaling plays an important role in EPC release during retinal NV in OIR.
    Investigative ophthalmology & visual science 10/2013; · 3.43 Impact Factor
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    ABSTRACT: To investigate the effect of benzalkonium chloride (BAK) on corneal nerves. Fifty-four adult New Zealand Albino rabbits were randomly divided into 3 groups. BAK at concentrations of 0.005%, 0.01%, or 0.02% was applied once daily to 1 eye of each rabbit for 9 days. The contralateral untreated eyes were used as controls. Corneal mechanical sensitivity, aqueous tear production, tear break-up time (BUT), fluorescein, and Rose Bengal staining scores were compared with those of control values on days 3, 6, and 9. Corneal whole mounts were immunostained with a specific antitubulin βIII antibody to label nerve fibers. Epithelial superficial nerve terminal, subbasal, and stromal nerve fiber densities were quantified. The structure of the central cornea was examined by means of in vivo confocal microscopy on day 9. The topical application of BAK resulted in lower corneal sensitivity and higher Rose Bengal staining scores on day 3, whereas there were no significant changes in the BUT, Schirmer, and corneal fluorescein scores. Decreased nerve densities in superficial and subbasal layers were observed in BAK-treated eyes on days 3 and 6, respectively. The eyes treated with 0.02% BAK exhibited significantly reduced Schirmer scores, BUT, and stromal nerve fiber density, and increased fluorescein staining scores on day 9. Corneal superficial epithelial cell size was significantly larger in all BAK-treated eyes compared with that in control eyes. The topical application of BAK can quickly cause corneal hypoesthesia without tear deficiency. Changes in corneal innervation significantly correlate with BAK-induced ocular surface changes.
    Cornea 10/2013; · 1.75 Impact Factor
  • Ophthalmology 09/2013; 120(9):e65-6. · 5.56 Impact Factor
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    ABSTRACT: PURPOSE. To develop a mouse model of limbal stem cell deficiency (LSCD) by topical administration of benzalkonium chloride (BAC). METHODS. BAC solutions (0% to 0.5%) were applied to the mouse ocular surface for 4 weeks. Corneal neovascularization, inflammation, and epithelial status were observed under slitlamp microscope. The eyeball and ocular surface tissues were collected at 4 weeks and 12 weeks, and labeled with a series of antibodies. Limbal structure was evaluated by light and transmission electron microscopy (TEM). Corneal impression cytology was performed at 12 weeks and labled with periodic acid Schiff (PAS) reagents. RESULTS. 0.5% BAC four times per day for 28 days successfully induced the typical manifestations of LSCD, including corneal neovascularization, severe inflammation in the stroma, and diffuse epithelial defect (P<0.001). K19 and K13 were positive on the corneal surface. P63 and ABCG2 expression were abolished in the limbal epithelium. β-catenin was negative in the basal layer. TEM revealed the irregular basement membrane and the loss of stem cell-specific ultrastructure in the limbal basal epithelium. In 0.5% BAC group, goblet cells could not be observed on day 28 but emerged after the cessation of BAC, and remained over the cornea after eight weeks. K13-positive cells were still present over the cornea with the loss of K12. CONCLUSIONS. Topical administration of BAC at high concentration and frequency in mouse induces ocular surface changes resembling that of LSCD in humans, representing a novel model of LSCD.
    Investigative ophthalmology & visual science 08/2013; · 3.43 Impact Factor
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    ABSTRACT: Kallistatin is a member of the serine proteinase inhibitor superfamily. Kallistatin levels have been shown to be decreased in the vitreous, while increased in the circulation of patients with diabetic retinopathy (DR). Over-activation of the Wnt pathway is known to play pathogenic roles in DR. To investigate the role of kallistatin in DR and in Wnt pathway activation, we generated kallistatin transgenic (kallistatin-TG) mice over-expressing kallistatin in multiple tissues including the retina. In the oxygen-induced retinopathy (OIR) model, kallistatin over-expression attenuated ischemia-induced retinal neovascularization. In diabetic kallistatin-TG mice, kallistatin over-expression ameliorated retinal vascular leakage, leukostasis and over-expression of VEGF and ICAM-1. Furthermore, kallistatin over-expression also suppressed Wnt pathway activation in the retinas of the OIR and diabetic models. In diabetic Wnt reporter (BAT-gal) mice, kallistatin over-expression suppressed retinal Wnt reporter activity. In cultured retinal cells, kallistatin blocked Wnt pathway activation induced by high glucose and by Wnt ligand. Co-precipitation and ligand binding assays both showed that kallistatin binds to a Wnt co-receptor LRP6 with high affinity (Kd=4.5 nM). These observations suggest that kallistatin is an endogenous antagonist of LRP6 and inhibitor of Wnt signaling. The blockade of Wnt signaling may represent a mechanism for its anti-angiogenic and anti-neuroinflammatory effects.
    Diabetes 07/2013; · 7.90 Impact Factor
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    ABSTRACT: Endothelial-to-mesenchymal transition (EnMT) is a cell transformation process involved in both morphogenesis and pathogenesis. EnMT of corneal endothelial cells happens after endothelial injury and during ex vivo culture. Previous studies have shown that the transforming growth factor-β signaling pathway is involved in this transition. In this study, we found that rat corneal endothelial cells could spontaneously undergo EnMT during ex vivo culture. This change in rat corneal endothelial cells was associated with Notch signaling pathway activation after the first passage, which was blocked by the Notch inhibitor, DAPT. This inhibitor also prevented transforming growth factor β1-, β2-, and β3-induced EnMT and reversed transformed rat corneal endothelial cells to a normal phenotype. Furthermore, DAPT treatment blocked retrocorneal membrane formation in a rat corneal endothelium damage model. Our study indicates that the Notch signaling pathway is involved in the corneal EnMT process, which may be a novel therapeutic target for treating corneal endothelial fibrogenic disorders.
    American Journal Of Pathology 07/2013; · 4.60 Impact Factor
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    ABSTRACT: To determine if a serine protease inhibitor A3K (SA3K) reduces TNF-α-induced declines in rabbit corneal endothelial junctional barrier integrity. New Zealand rabbit corneas were incubated ex vivo for 24 h in DMEM containing 10% FBS with or without TNF-α, in the presence or absence of SA3K at different concentrations. Corneal endothelial barrier function permeability was determined based on measurements of FITC-dextran tissue accumulation. Apical junctional complex (AJC) integrity was evaluated of ZO-1, VE-cadherin and F-actin and associated microtubules, as well as myosin light chain (MLC) by immunofluorescent staining, Western blot analysis, and/or RT-PCR. TNF-α (20ng/ml) increased corneal endothelial FITC-dextran permeability by 1.8-fold compared with the untreated control. SA3K (100-200 nM) dose dependently suppressed TNF-α-induced increases in permeability. SA3K nearly completely reversed TNF-α-induced disruptions of tight junctional ZO-1 and subjacent adherens junctions VE-cadherin integrity. Interestingly, SA3K reversed TNF-α-induced disruption of AJC linkage to the cytoskeletal F-actin array by restoring F-actin double-band structures. SA3K also attenuated TNF-α-induced microtubule disassembly. Furthermore, SA3K blocked increases in MLC phosphorylation status elicited by TNF-α. SA3K exposure markedly reduced TNF-α-induced disruption of barrier structure and function in the rabbit corneal endothelium by maintaining AJC integrity. These protective effects are due to suppression of MLC activation. SA3K may have in vivo a therapeutic potential to offset TNF-α-induced declines in endothelial barrier structural integrity and function.
    Investigative ophthalmology & visual science 07/2013; · 3.43 Impact Factor
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    ABSTRACT: Human amniotic membrane (AM) is avascular but contains various beneficial bioactive factors, its extract (AE) is also effective in treating many ocular surface disorders. In this study, we for the first time evaluated the therapeutic effects of AE on dry eye induced by Benzalkonium Chloride in a BALB/c mouse model. Topical application of AE (1.5 and 3 μg/eye/day) resulted in significantly longer tear break-up time on Day 3 and 6, lower fluorescein staining scores on Day 3, and lower inflammatory index on Day 6. AE reduced corneal epithelial K10 expression, inflammatory infiltration, and levels of TNF-α, IL-1β and IL-6 in BAC treated mice than that in the control mice. Moreover, decreased TUNEL positive cells in cornea and increased goblet cells in conjunctiva were also observed in AE treated corneas. Finally, AE induced more Ki-67 positive cells in corneal epithelium of dry eye mouse. Taken together, our data provide further support for BAC induced dry eye model as a valuable for dry eye study and suggest a great potential for AE as a therapeutic agent in the clinical treatment of dry eye.
    Experimental Eye Research 06/2013; · 3.03 Impact Factor
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    ABSTRACT: This study was to investigate the proliferation and differentiation of mouse corneal epithelial progenitor cell in hypoxic airlift culture. Mouse corneal epithelial progenitor cell line progenitor cells were cultured under airlift with normoxic and hypoxic conditions for various durations up to 2 wk. Under normoxic conditions when exposed to air, the hyperproliferation and abnormal epidermal-like differentiation of mouse corneal epithelium was induced, whereas when exposed to air under hypoxic conditions, although we observed augmented proliferation, the abnormal differentiation was inhibited. The mechanism by which hypoxia prevents abnormal differentiation may involve downregulation of Wnt signaling pathways, which were inhibited in cells cultured with hypoxic airlift technique. In conclusion, hypoxia can prevent abnormal differentiation while enhancing the proliferation of corneal epithelial cells by blocking Wnt/β-catenin signaling pathway.
    In Vitro Cellular & Developmental Biology - Animal 06/2013; · 1.29 Impact Factor
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    ABSTRACT: PURPOSE: To investigate the efficacy of low-temperature airlift preservation of human corneal limbal tissue for ex vivo expansion and allograft keratolimbal transplantation. METHODS: Human limbal tissue was either submerged or airlifted in Optisol-GS medium and preserved at 4 oC for up to eight days. H&E and E-cadherin staining was performed to investigate epithelial structure and cell-cell junction. Epithelial cell differentiation and proliferation were studied using the biomarkers such as K10, K12, K14, Ki67, and p63. Cell apoptosis was detected with the TUNEL assay. The epithelial progenitor cell pool was evaluated by clonal culture of epithelial cells on 3T3 feeder layers. For clinical application, keratolimbal transplantation was performed in three patients with partial limbal stem cell deficiency, using limbal tissues preserved under the airlift manner. Pre- and post-operative evaluations were conducted by slit-lamp microscopy and fluorescein staining. RESULTS: After eight days, intact epithelia with strong cell-cell junctions were retained only in airlifted tissues. Airlifting maintained a normal corneal differentiation pattern along with low proliferation activity and increased proliferation potential, but little apoptosis. Epithelial cells harvested from the airlift preservation for up to eight days exhibited stable clonogenicity. Limbal tissues preserved under the airlift manner successfully reconstructed corneal and limbal surfaces in partial limbal stem cell deficient patients. CONCLUSIONS: Limbal tissues preserved under hypothermic airlift conditions maintain the intact structure, normal phenotype, high viability, and stem cell pool of limbal epithelia. Such a method may be utilized in eye bank tissue processing and corneal epithelial tissue engineering.
    Investigative ophthalmology & visual science 05/2013; · 3.43 Impact Factor
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    ABSTRACT: Cigarette smoke (CS) has been reported to induce autophagy in airway epithelial cells. The subsequent autophagic cell death has been proposed to play an important pathogenic role in chronic obstructive pulmonary disease (COPD); however, the underlying molecular mechanism is not entirely clear. Using CS extract (CSE) as a surrogate for CS, we found that it markedly increased the expressions of both LC3B-I and LC3B-II as well as autophagosomes in airway epithelial cells. This is in contrast to the common autophagy inducer (i.e., starvation) that increases LC3B-II but reduces LC3B-I. Further studies indicate that CSE regulated LC3B at transcriptional and post-translational levels. In addition, CSE, but not starvation, activated Nrf2-mediated adaptive response. Increase of cellular Nrf2 by either Nrf2 overexpression or the knockdown of Keap1 (an Nrf2 inhibitor) significantly repressed CSE-induced LC3B-I and II as well as autophagosomes. Supplement of NAC (a GSH precursor) or GSH recapitulated the effect of Nrf2, suggesting the increase of cellular GSH level is responsible for Nrf2 effect on LC3B and autophagosome. Interestingly, neither Nrf2 activation nor GSH supplement could restore the repressed activities of mTOR or its downstream effctor-S6K. Thus, the Nrf2-dependent autophagy-suppression was not due to the re-activation of mTOR-the master repressor of autophagy. To search for the downstream effector of Nrf2 on LC3B and autophagosome, we tested Nrf2-dependent genes (i.e., NQO1 and P62) that are also increased by CSE treatment. We found that P62, but not NQO1, could mimic the effect of Nrf2 activation by repressing LC3B expression. Thus, Nrf2->P62 appears to play an important role in the regulation of CSE-induced LC3B and autophagosome.
    PLoS ONE 01/2013; 8(4):e55695. · 3.73 Impact Factor

Publication Stats

287 Citations
158.33 Total Impact Points

Institutions

  • 2013
    • Fudan University
      • Department of Ophthalmology
      Shanghai, Shanghai Shi, China
  • 2008–2013
    • Xiamen University
      • Key Laboratory of the Ministry of Education For Cell Biology and Tumor Cell Engineering
      Amoy, Fujian, China
  • 2002–2011
    • Sun Yat-Sen University
      • State Key Laboratory of Oncology
      Guangzhou, Guangdong Sheng, China
    • Sun Yat-Sen University of Medical Sciences
      Shengcheng, Guangdong, China
  • 2010
    • Sun Yat-Sen University Cancer Center
      Shengcheng, Guangdong, China
  • 2002–2005
    • Zhongshan University
      中山, Guangdong, China