Meibomian Gland Alteration in Patients with Primary Chronic Dacryocystitis: An In vivo Confocal Microscopy Study

PURPOSE

To evaluate meibomian gland (MG) alterations in patients with primary chronic dacryocystitis (PCD) by in vivo confocal microscopy (IVCM), and to correlate the finding with clinical presentation.

METHODS

Twenty-eight eyes with the diagnosis of PCD and their contralateral unaffected eyes were studied and compared with 27 normal controls. All subjects completed an Ocular Surface Disease Index questionnaire (OSDI) and underwent slit-lamp biomicroscopy examination, tear break-up time (BUT) measurements, fluorescein staining, Schirmer test I, and an IVCM examination of the MG. IVCM parameters, including the MG acinar unit density (MGAUD), periglandular inflammatory cell density (ICD), MG acinar unit longest diameter (MGALD), and MG acinar unit shortest diameter (MGASD) and their correlation with clinical data were analyzed.

RESULTS

The mean MG expressibility scores, BUT values, and staining scores were significantly worse in eyes with PCD compared with the contralateral clinically unaffected eyes and controls (p < 0.05). A significant decrease in MGAUD was observed in PCD eyes compared with the controls and the contralateral clinically unaffected eyes. Conversely, the mean ICD and MGASD values were significantly higher in the PCD eyes. There were no significant differences in mean MGALD value between the PCD eyes and the contralateral clinically unaffected eyes. In addition, there were significant changes in the IVCM parameters in the contralateral unaffected eyes compared with the controls, including MGAUD, ICD, MGALD, and MGASD. All IVCM parameters showed a strong, significant correlation with MG dropout grades, MG expressibility, fluorescein staining scores, and OSDI values (all p < 0.05).

CONCLUSIONS

Patients with unilateral PCD demonstrated significant changes in MG as compared with the contralateral clinically unaffected eyes and controls. The MG function should be closely observed in these patients.

Keratocytes create stromal spaces to promote corneal neovascularization via MMP13 expression

PURPOSE

To investigate the exact mechanism by which keratocytes promote corneal neovascularization.

METHODS

The expression of matrix metalloproteinase 13 (MMP13), cluster of differentiation 146 (CD146), VEGFa, VEGFc, VEGF receptor (r)2, and VEGFr3 by normal and alkali-burned rat corneas was determined via quantitative (q)RT-PCR and/or Western blot analysis or in situ hybridization. Corneal neovascularization was observed under a slit lamp microscope and evaluated via immunohistochemistry. The cells that expressed MMP13 in the corneas were determined via sequential immunohistochemistry and in situ hybridization. The degradation of type I collagen was evaluated via the detection of hydroxyproline content and Western blot analysis. The effects of VEGFa and VEGFc on MMP13 expression were determined via luciferase reporter assay for the MMP13 promoter and primary keratocyte culture.

RESULTS

Matrix metalloproteinase 13 was predominantly expressed by epithelial cells in normal rat corneas, but it was expressed by cells in corneal stromas after alkali burns. The formation of new blood vessels was consistent with MMP13 expression and attenuated by a selective MMP13 inhibitor in alkali-burned corneas. Keratocytes were the major cells expressing MMP13 in corneal stromas after alkali burns. Through MMP13 expression, keratocytes directly degraded collagen type I to create stromal spaces, which were convenient for newly formed blood vessels to grow into. Expression of MMP13 and collagen type I degradation via keratocytes were induced by VEGFc through VEGFr3 and inhibited by antibodies for VEGFc and VEGFr3.

CONCLUSIONS

Keratocytes could directly degrade type I collagen and create stromal spaces, promoting corneal neovascularization through VEGFc/VEGFr3-induced MMP13 expression.

[Strengthen Chinese translational medicine research in ocular surface]

Translational medicine emphasizes the application of the results of basic research to clinical practice and the solution of clinical issues through basic research. It is very important for the development direction of the medical field. Over the past decade, the translational medicine research in ocular surface disease has drawn international attention and developed rapidly. This field in China has made great progress, but overall there are still some gaps with the international advanced level. We need to establish the concept and the platform of translational research, explore scientific and effective methods, and create a whole chain to enhance our ocular research. It also requires research institutions and government departments to give full support. Finally, we need to explore a suitable way for the development of Chinese translational medical research.

[Rethinking clinical significance of tear osmolarity measurement for dry eye diagnosis and therapeutic efficacy evaluation]

Increased tear osmolarity is one of the core mechanisms of dry eye and has been considered as an important diagnostic criterion, if not"gold standard", of dry eye. However, recent studies showed the limitations of tear osmolarity measurement not only in the diagnosis, but also in the therapeutic efficacy evaluation of dry eye. The clinical significance of tear osmolarity measurement has become a hot topic of argument. Herein, we review the publications on this topic and try to find the underlying causes of such argument.

An unusual case of Acanthamoeba Polyphaga and Pseudomonas Aeruginosa keratitis

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5168343391150859

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.

[Toxicity research status of benzalkonium chloride on ocular surface]

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.

Corneal alterations induced by topical application of commercial latanoprost, travoprost and bimatoprost in rabbit

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.

Genome-wide transcriptional analysis of differentially expressed genes in diabetic, healing corneal epithelial cells: hyperglycemia-suppressed TGFβ3 expression contributes to the delay of epithelial wound healing in diabetic corneas

Patients with diabetes mellitus (DM) may develop corneal complications and delayed wound healing. The aims of this study are to characterize the molecular signatures and biological pathways leading to delayed epithelial wound healing and to delineate the involvement of TGFβ3 therein. Genome-wide cDNA microarray analysis revealed 1,888 differentially expressed genes in the healing epithelia of normal (NL) versus type 1 DM rat corneas. Gene ontology and enrichment analyses indicated TGFβ signaling as a major altered pathway. Among three TGFβ isoforms, TGF-β1 and β3 were upregulated in response to wounding in NL corneal epithelial cells (CECs), whereas the latter was greatly suppressed by hyperglycemia in rat type 1 and 2 and mouse type 1 DM models. Functional analysis indicated that TGF-β3 contributed to wound healing in NL corneas. Moreover, exogenously added TGF-β3 accelerated epithelial wound closure in type 2 rat and type 1 mouse DM corneas via Smad and PI3K-AKT signaling pathways, autoregulation, and/or upregulation of Serpine1, a well-known TGFβ target gene. Taken together, our study for the first time provides a comprehensive list of genes differentially expressed in the healing CECs of NL versus diabetic corneas and suggests the therapeutic potential of TGF-β3 for treating corneal and skin wounds in diabetic patients.

[Effects of amniotic extraction on epithelial wound healing and stromal remodelling after excimer laser keratectomy in rabbit cornea]

OBJECTIVE

To investigate the effects and mechanism of amniotic extraction on corneal healing after photorefractive keratectomy (PRK).

METHODS

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 deoxyribonucleotidyl transferase-mediated deoxyuridine triphosphate 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.

RESULTS

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).

CONCLUSION

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.

Clinical efficacy of 0.1% pranoprofen in treatment of dry eye patients: a multicenter, randomized, controlled clinical trial

BACKGROUND

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.

METHODS

It is a prospective, multi-center, randomized, controlled, parallel group study. One hundred and fifteen patients with mild to moderate dry eye disease (55-60 in each treatment group) participated in this multi-center study. Patients were randomly administered with eyedrops containing 0.1% pranoprofen (PRA) plus 0.1% sodium hyaluronate (SH) or SH only, three times daily for 28 days, followed by a 1-week after treatment observation. Dry eye symptom score (DESS), fluorescein corneal staining (FLCS), tear break-up time (TBUT), and Shirmer 1 tear test (ST1, without anesthesia) were evaluated or conducted before treatment and at each study visit. Conjunctival impression cytology was taken from the patients treated with PRA plus SH before and after treatment and real-time polymerase chain reaction (RT-PCR) was performed to detect the changes of human leukocyte antigen DR (HLA-DR) and intercellular adhesion molecule 1 (ICAM-1).

RESULTS

Patients treated with PRA plus SH showed gradual improvements of DESS, FLCS, and TBUT. Between-group comparisons of FLCS and TBUT have statistically significant differences from day 14. Good tolerance with no severe adverse events was found in both groups. Patients treated with PRA plus SH had a reduced expression level of HLA-DR and were statistically different after 28 days of therapy.

CONCLUSIONS

The application of PRA at a dose of 0.1% was well tolerated and benefited to the patients with mild to moderate dry eye disease. The underlying mechanism of its efficacy may be associated with the reduction of inflammatory factors of conjunctival epithelial cells.

Abstract P2-03-11: In situ imaging of the tumor cavity during breast lumpectomy using optical coherence tomography

Re-operation rates for breast lumpectomy procedures are exceedingly high, often over 30%, depending on the institution and surgical technique. Because current standard-of-care relies on post-operative histopathology to provide a microscopic view and assessment of surgical margins, there has been great interest in developing new imaging solutions to visualize tissues intraoperatively with high-resolution, and provide real-time feedback on the margin status. While it is possible to use a variety of microscopic imaging methods in the operating suite, including frozen-section histology, touch-prep cytology, confocal or scattering-based microscopy, all these techniques are limited to visualizing margins on ex vivo resected specimens, and do not provide a means for visualizing the in situ tumor cavity for evidence of positive margins or residual disease.

Optical coherence tomography (OCT) is a high-resolution, real-time, optical biomedical imaging technology that is the optical analogue to ultrasound imaging, except images are based on backscattered near-infrared light. OCT is capable of performing optical biopsies of in situ tissue at resolutions that approach those in histopathology. With the use of an advanced computed imaging technique called ISAM (Interferometric Synthetic Aperture Microscopy), even higher imaging resolution over larger depths is possible, commensurate with the depths (1-2 mm) visualized by pathologists to determine negative, close, or positive margins. Past studies by our group and others have demonstrated the feasibility of intraoperative OCT for assessing tumor margin and lymph node status during breast cancer surgery, but to date, all studies have been performed on resected lumpectomy tissue.

In this study, we report the development of a novel handheld surgical imaging probe that enables 2-D and 3-D OCT/ISAM imaging of the in situ tumor cavity, in addition to the margins of excised specimens. To date, this handheld OCT/ISAM probe has been used in 10 breast cancer surgeries where both in situ and ex vivo imaging was performed. Four of these cases involved in situ imaging of the cavity margin after a suspicious area was visually and tactically identified, and was subsequently resected, followed by ex vivo imaging and validating post-operative histopathology. Representative cases included fibroadipose tissue, fibroadenomas, and high-grade ductal carcinoma in situ.

Distinct microstructural features identified on OCT/ISAM and confirmed with histopathology demonstrate that this technique can visualize the in situ tumor cavity, as well as the surgical margins on resected specimens, with micron-scale resolution. OCT/ISAM has the potential to determine margin status in real-time during the surgical procedure, when further surgical resection to establish clear margins and reduce re-operation rates is possible.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-03-11.

Antiangiogenic and antineuroinflammatory effects of kallistatin through interactions with the canonical Wnt pathway

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). Overactivation 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 overexpressing kallistatin in multiple tissues including the retina. In the oxygen-induced retinopathy (OIR) model, kallistatin overexpression attenuated ischemia-induced retinal neovascularization. In diabetic kallistatin-TG mice, kallistatin overexpression ameliorated retinal vascular leakage, leukostasis, and overexpression of vascular endothelial growth factor and intracellular adhesion molecule. Furthermore, kallistatin overexpression also suppressed Wnt pathway activation in the retinas of the OIR and diabetic models. In diabetic Wnt reporter (BAT-gal) mice, kallistatin overexpression suppressed retinal Wnt reporter activity. In cultured retinal cells, kallistatin blocked Wnt pathway activation induced by high glucose and by Wnt ligand. Coprecipitation and ligand-binding assays both showed that kallistatin binds to a Wnt coreceptor LRP6 with high affinity (Kd = 4.5 nmol/L). 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 antiangiogenic and antineuroinflammatory effects.

Regulation of endothelial progenitor cell release by Wnt signaling in bone marrow

PURPOSE

Endothelial progenitor cells (EPC) have been shown to participate in ischemia-induced retinal neovascularization (NV). Overactivation of Wnt signaling has 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. The EPC, marked as c-Kit(+)/Tie-2(+) cells in the peripheral blood and bone marrow, were quantified using flow cytometry following immunolabeling. The Wnt signaling activity was evaluated by measuring nonphosphorylated β-catenin levels and X-gal staining in the Wnt reporter mice (Bat-gal mice).

RESULTS

The c-Kit(+)/Tie-2(+) cells were increased significantly in the peripheral blood and bone marrow of mice with OIR, compared to non-OIR mice. Overexpression 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 overexpression 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 the retina and bone marrow cells in Bat-gal mice.

CONCLUSIONS

The Wnt signaling pathway has an important role in EPC release during retinal NV in OIR.

[Emphasizing the clinical investigation of dry eye]

In the past twenty years, with the rapid development of dry eye research in China, significant progresses have been achieved and there has been a remarkable improvement in diagnostic rate and clinical outcomes. Publication and popularization of the clinical diagnosis and treatment recommendations for dry eye from consensus of expert advice provides criteria for clinical work of dry eye. There has still been a significant gap between our research and world's advanced level in dry eye, therefore clinical investigations of high level will be intensively promoted to reveal the epidemiologic and clinical characteristics of dry eye populations in China, and establish the diagnostic criteria for Chinese patients, develop the clinical research on dry eye drugs and home-made clinical devices. Based on evidence-based research evidences, criteria for diagnosis and treatment of dry eye will be established and the clinical investigation of dry eye will be developed to reach the world's advanced level.

A mouse model of limbal stem cell deficiency induced by topical medication with the preservative benzalkonium chloride

PURPOSE

To develop a mouse model of limbal stem cell deficiency (LSCD) by topical administration of benzalkonium chloride (BAC).

METHODS

BAC solutions (0%-0.5%) were applied to the mouse ocular surface for 4 weeks. Corneal neovascularization, inflammation, and epithelial status were observed under slit-lamp microscope. The eyeball and ocular surface tissues were collected at 4 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 specimens were labeled with periodic acid Schiff (PAS) reagents.

RESULTS

BAC (0.5%) 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). Conjunctival epithelium markers K19 and K13 were positive on the corneal surface. Expression of the putative limbal stem cell markers P63 and ABCG2 was 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 the 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 8 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 those of LSCD in humans, representing a novel model of LSCD.

Notch signal regulates corneal endothelial-to-mesenchymal transition

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 N-[N-(3,5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (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.

Amniotic membrane extract ameliorates benzalkonium chloride-induced dry eye in a murine model

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.

[Abnormal epithelial differentiation and tear film alteration in pterygium]

OBJECTIVE

To investigate the differentiation and proliferation of the conjunctival epithelium and tear film function in pterygia.

METHODS

It was a retrospective study. Fifteen patients (15 eyes) who underwent excision for pterygium were enrolled in this study. Immunostaining for K10, K14, K19, MUC5AC, K16, Ki67 and P63 was performed on the pterygial epithelium and normal conjunctival epithelium. Schirmer I test was performed, and the tear film break-up time (BUT) was evaluated just prior to and 6 months after surgery. Multi-factor regression analysis was assessed to observe if there is a correlation between pterygial growth and tear film function.

RESULTS

The average absorbency of K19 and MUC5AC immuno-staining all significantly changed (3727.86 ± 2544.73 vs. 25 528.00 ± 12 901.06, 2080.48 ± 2340.17 vs. 7182.51 ± 3069.20, t = 9.261,3.538, P < 0.05), and increased in K10 and K14 in patients with pterygia compared with normal conjunctivae keratin (2017.51 ± 2114.3 vs. 0, 6027.5 ± 1058.32 vs. 2123.28 ± 1249.09, t = -6.151, P < 0.05). Furthermore, pterygial epithelium showed activated proliferation, evidenced by significantly up-regulated expression of K16, P63 and Ki67 compared to normal control. The Schirmer I test did not indicate any significant differences pre- and post-operatively. However, the BUT was significantly prolonged 1 month post surgery compared to pre-surgery (t = -4.222, P < 0.05).

CONCLUSION

This study indicates that abnormal epithelial differentiation and proliferation are present in pterygium , which is characterized by squamous metaplasia, accompanied with instability of tear film and normal basic tear secretion.

Regulation of Cigarette Smoke (CS)-Induced Autophagy by Nrf2

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.

Nitrosative stress plays an important role in Wnt pathway activation in diabetic retinopathy

AIMS

Diabetes is associated with nitrosative stress in multiple tissues. Overactivation of the Wnt pathway has been shown to play a pathogenic role in diabetic retinopathy (DR). The purpose of this study was to investigate whether nitrosative stress contributes to aberrant activation of Wnt signaling in diabetes.

RESULTS

Nitrosative stress induced by peroxynitrite (PN), 4-hydroxynonenal (HNE), or high glucose (HG) in retinal cells was assessed by a dichlorofluorescein fluorescence assay or by Western blot analysis and enzyme-linked immunosorbent assay of 3-nitrotyrosine (3-NT). These nitrosative stress inducers activated the canonical Wnt pathway, as shown by Western blot analysis of phosphorylated low-density lipoprotein receptor-related protein 6 (pLRP6), total and nuclear β-catenin levels, Luciferase reporter assay, and expression of the Wnt target genes intercellular adhesion molecule 1 (ICAM-1) and vascular endothelial growth factor (VEGF). Uric acid (UA), a PN scavenger, and 5,10,15,20-Tetrakis (4-sulfonatophenyl) porphyrinato Iron III Chloride (FeTPPS), a PN decomposition catalyst, suppressed Wnt signaling and ICAM-1 and VEGF overexpression induced by PN, HNE, and HG. Furthermore, UA and FeTPPS also inhibited Wnt signaling induced by the Wnt ligand. In streptozotocin-induced diabetic rats, retinal levels of 3-NT, β-catenin, nuclear β-catenin, pLRP6, VEGF, and ICAM-1 were markedly increased. UA treatment for 6 weeks ameliorated diabetes-induced Wnt signaling in the diabetic rat retina. The UA treatment also decreased inflammatory cell infiltration and extraverted serum albumin in the perfused retina of diabetic rats, suggesting decreased retinal inflammation and vascular leakage.

INNOVATION AND CONCLUSION

Nitrosative stress in diabetes contributes to Wnt pathway activation in the retina, and Wnt signaling may mediate the pathogenic effects of nitrosative stress in DR.

Increased importin 13 activity is associated with the pathogenesis of pterygium

PURPOSE

We previously reported that importin 13 (IPO13), a member of the importin-β family of nuclear import proteins, regulates nuclear import of the glucocorticoid receptor in airway epithelial cells, IPO13 serves as a potential marker for corneal epithelial progenitor cells, and IPO13 is associated with corneal cell proliferation. Here we investigated the role of IPO13 in the pathogenesis of pterygium and the underlying mechanism including interaction with other cell proliferation-related factors: keratin 17 (K17), a lesional protein and a member of the type I keratins, and c-Jun, a protein of the activator protein-1 complex.

METHODS

Tissue samples were collected from primary pterygia, recurrent pterygia, and normal conjunctiva to perform the following experiments: immunohistochemical measurement of IPO13 and K17. Pterygium epithelial cells (PECs) were cultured in keratinocyte serum-free defined medium to examine the expression of IPO13 and K17. Lentivirus-mediated silencing and overexpression IPO13 testing was conducted, and K17 alternation was evaluated with western blot and immunostaining. In addition, the translocation of c-Jun (a K17 regulator) was further examined after IPO13 was silenced.

RESULTS

IPO13 activity was significantly increased in the basal layer of the epithelium of the pterygium. In cultured PECs, overexpression or knockdown of the IPO13 gene increased or decreased PEC proliferation, respectively. IPO13 was colocalized with K17 in the epithelium of the pterygium, and overexpression or knockdown of the IPO13 gene induced upregulation or downregulation of K17 expression in PECs, respectively. In addition, silencing of the IPO13 gene blocked nuclear translocation of c-Jun.

CONCLUSIONS

We provided novel evidence that IPO13 may contribute to the pathogenesis of pterygium via modulation of K17 and c-Jun.

Significance of heterogeneous Twist2 expression in human breast cancers

Background

Twist2 (Dermo1) has been shown to mediate the epithelial-mesenchymal transition (EMT) to promote tumor invasion and even metastasis. However, the involvement of EMT in breast cancer progression is highly debated, partially due to clinical observations showing that the majority of human breast carcinoma metastases express E-cadherin and maintain their epithelial morphology. The molecular mechanism by which Twist2 participates in EMT of breast cancer in vivo remains poorly understood.

Methods

We examined Twist2 expression pattern in human breast carcinomas by western blot and tissue microarray, and analyzed Twist2 cellular localization by confocal microscopy, cell fractionation and other approaches.

Results

Twist2 expression was significantly increased in breast cancer. Cytoplasmic Twist2 positive cancer cells expressing E-cadherin on the cellular membrane were mainly located at tumor center of primary carcinomas and lymph metastases, while cancer cells with nuclear Twist2 clearly showed loss of E-cadherin and were detected at the invasive front in ductal breast carcinomas. In addition, ectopically stable-expressed Twist2 was found to localize in the cytoplasm of cancer cells. Collectively, these data indicate that upregulation of cytoplasmic Twist2 is correlated with tumor histological type and tumor metastasis in human breast cancers.

Conclusion

The differential cellular distribution of Twist2 may be associated with tumor progression. The cytoplasmic Twist2 in cancer cells at tumor center of primary carcinomas and lymph metastases contributes to the maintenance of epithelial cancer characteristics expressing E-cadherin in a noninvasive state, while the nuclear Twist2 at the cancer invasion front activates EMT to deprive epithelial property of neoplastic cells, thus facilitating invasion and metastasis. These findings suggest that heterogeneous expression of Twist2 in tumors may have a functional link to tumor progression.

Iron solubility related to particle sulfur content in source emission and ambient fine particles

The chemical factors influencing iron solubility (soluble iron/total iron) were investigated in source emission (e.g., biomass burning, coal fly ash, mineral dust, and mobile exhaust) and ambient (Atlanta, GA) fine particles (PM2.5). Chemical properties (speciation and mixing state) of iron-containing particles were characterized using X-ray absorption near edge structure (XANES) spectroscopy and micro-X-ray fluorescence measurements. Bulk iron solubility (soluble iron/total iron) of the samples was quantified by leaching experiments. Major differences were observed in iron solubility in source emission samples, ranging from low solubility (<1%, mineral dust and coal fly ash) up to 75% (mobile exhaust and biomass burning emissions). Differences in iron solubility did not correspond to silicon content or Fe(II) content. However, source emission and ambient samples with high iron solubility corresponded to the sulfur content observed in single particles. A similar correspondence between bulk iron solubility and bulk sulfate content in a series of Atlanta PM2.5 fine particle samples (N = 358) further supported this trend. In addition, results of linear combination fitting experiments show the presence of iron sulfates in several high iron solubility source emission and ambient PM2.5 samples. These results suggest that the sulfate content (related to the presence of iron sulfates and/or acid-processing mechanisms by H(2)SO(4)) of iron-containing particles is an important proxy for iron solubility.

Netrin-1 simultaneously suppresses corneal inflammation and neovascularization

PURPOSE

To investigate the effect of netrin-1 on alkali burn-induced corneal inflammation and neovascularization.

METHODS

The expression of netrin-1 and its receptors UNC5A, UNC5B, UNC5C, UNC5D, adenosine 2b receptor (A2BAR), deleted in colorectal cancer (DCC), and neogenin in normal and alkali-burned rat cornea were determined by RT-PCR and/or Western blot analysis, or immunostaining. Topical netrin-1 protein was applied to treat rat corneal alkali-burn injury for 14 consecutive days, started right after the injury or 10 days postinjury. Corneal inflammation and neovascularization were observed under slit lamp microscope. The apoptosis of corneal cells was determined by terminal deoxynucleotidyl transferase-mediated nick end labeling assay. Corneal inflammatory cell infiltration was evaluated by immunostaining of anti-PMN and anti-ED1 antibodies. The expression of epidermal growth factor (EGF), vascular epidermal growth factor (VEGF), and pigment epithelium-derived factor (PEDF) in rat cornea was determined by Western blot analysis.

RESULTS

Netrin-1 and its receptor UNC5B were expressed in normal rat corneal epithelium and stromal cells, and their expression decreased after corneal alkali burn. Exogenous netrin-1 administered on rat ocular surfaces resolved alkali burn-induced corneal inflammation, and also suppressed corneal neovascularization. Furthermore, netrin-1 could reverse neovascularization in alkali-burned cornea. The authors found that netrin-1 executed the functions through various mechanisms, including upregulating EGF expression, accelerating epithelial wound healing, inhibiting neutrophil and macrophage infiltration, reducing corneal cell apoptosis, and restoring the equilibrium of VEGF and PEDF in the wounded cornea.

CONCLUSIONS

Netrin-1 could dampen inflammation, inhibit, and reverse neovascularization in alkali-burned cornea.

Therapeutic effects of epidermal growth factor on benzalkonium chloride-induced dry eye in a mouse model

PURPOSE

To investigate the therapeutic effects and possible mechanisms of epidermal growth factor (EGF) on the mouse dry eye model induced by benzalkonium chloride (BAC).

METHODS

The eye drop containing EGF was topically administered (3 ng per day) on a BAC-induced dry eye model. The following clinical indications of dry eye were evaluated on Days 2, 4, and 6: tear break-up time (BUT), corneal fluorescein staining, inflammatory index, and tear volume. Global specimens were collected on Day 6 and then the following examinations were performed: histologic investigation, TUNEL assay to measure the dead cells, periodic acid-schiff (PAS) assay to detect goblet cells, and immunostaining of antibodies of Ki-67, EGF receptor (EGFR), and MUC1 in the corneas. The levels of EGFR and p-ERK of the corneas were also measured by Western blot analysis.

RESULTS

EGF resulted in longer BUTs on Days 2 and 6, lower fluorescein staining scores on Days 4 and 6, while no significant changes in inflammatory index or tear volume. EGF induced higher EGFR expression in corneal tissues by immunofluorescent staining and Western blot analysis. EGF also upregulated p-ERK, increased Ki-67 positive cells, and decreased TUNEL positive cells. In addition, EGF significantly increased the goblet cells number and MUC1 expression in the epithelium.

CONCLUSIONS

Topical application of EGF presented clinical improvements on dry eye by stabilizing the tear film and maintaining the integrity of epithelium. The results indicate that EGF has potential as a therapeutic agent in clinical treatment of dry eye.

[Therapeutic effects of Pyranoprofen on the mouse dry eye induced by topical medication of Benzalkonium Chloride]

OBJECTIVE

Randomized controlled experimental study to investigate the therapeutic effect and the possible mechanism of Pranoprofen on the recovery of dry eye induced by topical medication of Benzalkonium Chloride (BAC) in mouse.

METHODS

It was an experimental study. Seventy BALB/c mice were treated with topical administration of 0.25% BAC to establish the dry eye condition. Based on the consistency of break-up time of tear-film (BUT), corneal fluorescein staining scores and inflammation index, the eyes were re-selected and randomly divided into four groups on day (D) 21 after the BAC treatment. Group A was set up as blank control, while group B, C and D were treated respectively with 0.1% sodium hyaluronate eye drops, 0.1% fluorometholone eye drops plus 0.1% sodium hyaluronate eye drops, 0.1% pyranoprofen eye drops plus 0.1% sodium hyaluronate eye drops. BUTs, tear volumes, corneal fluorescein staining scores and inflammation index were evaluated in each group on D0, 1, 3 and 5 after the therapeutic treatment. Global specimens were collected on D6. Sections were stained with hematoxylin and eosin (HE) or by periodic acid-schiff (PAS) assay, and labeled with cytokeratin 10 (K10) antibody. The expression of tumor necrosis factor-α (TNF-α) in the cornea and conjunctiva was quantified by western blot.

RESULTS

72 eyes were included in the sequential experiment, 18 eyes for each group. On D0, 1 and 3, no clinical differences were observed among the groups. On D5, the BUT was (2.933 ± 0.320), (2.900 ± 0.280), (3.464 ± 0.498) and (3.643 ± 0.413) s in group A, B, C and D respectively; the BUTs in group C and D were significant longer than those of group A and B (F = 13.774, P = 0.000). The corneal fluorescein staining score was (11.640 ± 1.008), (11.790 ± 1.188), (10.330 ± 1.371) and (10.270 ± 1.104)s in group A, B, C and D respectively; the scores in group C and D were significant lower than those of group A and B (F = 6.145, P = 0.001). The corneal inflammatory index was (0.232 ± 0.059), (0.229 ± 0.078), (0.151 ± 0.055) and (0.154 ± 0.056) in group A, B, C and D respectively; the index in group C and D were significant lower than those of group A and B (F = 6.703, P = 0.001). No significant difference was found in tear volume among groups. No significant difference was found between Pyranoprofen and Fluorometholone treatment in BUT, corneal fluorescein score or inflammatory index. Corneal morphology showed the feature of thicker corneal epithelial layer in group A and uniformity in group C and D. PAS assay revealed similar goblet cell numbers in group C and D, but less goblet cells in group A and B. Cytokeratin 10 was almost negatively expressed in Pranoprofen or Fluorometholone treated groups, and remained positive in the corneal epithelium with other treatments. The level of TNF-α in the cornea was down-regulated in Pranoprofen or Fluorometholone treated groups.

CONCLUSIONS

Pranoprofen or Fluorometholone combined with sodium hyaluronate treatment presented similar therapeutic effects on BAC-induced mouse dry eye, with the more stable tear film, the better regularity of epithelium recovery, the down-regulation of inflammatory TNF-α, the increased number of goblet cells, and the elimination of squamous metaplasia, when compared with the treatment of sodium hyaluronate eye drops only. Our results showed the great potentialities of Pranoprofen in the clinical treatment of ocular surface inflammation in the mild and severity dry eye.

Corneal alternations induced by topical application of benzalkonium chloride in rabbit

Benzalkonium chloride (BAC) is the most common preservative in ophthalmic preparations. Here, we investigated the corneal alternations in rabbits following exposure to BAC. Twenty-four adult male New Zealand albino rabbits were randomly divided into three groups. BAC at 0.01%, 0.05%, or 0.1% was applied twice daily to one eye each of rabbits for 4 days. The contralateral untreated eyes were used as control. Aqueous tear production and fluorescein staining scores of BAC-treated eyes were compared with those of controls. The structure of the central cornea was examined by in vivo confocal microscopy. Expression of mucin-5 subtype AC (MUC5AC) in conjunctiva was detected by immunostainig on cryosections. Corneal barrier function was assessed in terms of permeability to carboxy fluorescein (CF). The distribution and expression of ZO-1, a known marker of tight junction, and reorganization of the perijunctional actomyosin ring (PAMR) were examined by immunofluorescence analysis. Although there were no significant differences between control and BAC-treated eyes in Schirmer scores, corneal fluorescein scores and the number of conjunctival MUC5AC staining cells, in vivo confocal microscopy revealed significant epithelial and stromal defects in all BAC-treated corneas. Moreover, BAC at 0.1% resulted in significant increases in central corneal thickness and endothelial CF permeability, compared with those in control eyes, and endothelial cell damage with dislocation of ZO-1 and disruption of PAMR. Topical application of BAC can quickly impair the whole cornea without occurrence of dry eye. A high concentration of BAC breaks down the barrier integrity of corneal endothelium, concomitant with the disruption of PAMR and remodeling of apical junctional complex in vivo.

Oxygen tension affects terminal differentiation of corneal limbal epithelial cells

Oxygen concentration has been shown to be crucial in the proliferation and differentiation of various types of cells, while the impact of oxygen tension on the lineage commitment of epithelial cells remains elusive. In this study, we investigated the effect of hypoxia on the differentiation of corneal limbal epithelium using an ex vivo squamous metaplasia model. Under normoxic conditions when exposed to air, the hyperproliferation and abnormal epidermal-like differentiation of human corneal limbal epithelium was induced, whereas when exposed to air under hypoxic conditions, although we observed augmented proliferation, the abnormal differentiation was inhibited. The Notch signaling pathway was activated in hypoxic cultures, whereas the p38 MAPK signaling pathway was downregulated. The addition of Notch inhibitor under hypoxic conditions restored the activation of p38 MAPK and resulted in the recidivation of limbal epithelial cells to epidermal-like differentiation. Moreover, the epidermal-like differentiation of rabbit limbal epithelial cells was also blocked under hypoxic conditions in corneal epithelial cell sheets engineered ex vivo. We concluded that hypoxia can prevent abnormal differentiation while enhancing the proliferation of corneal limbal epithelial cells. Hypoxia coupled with air exposure can be used in the tissue engineering of corneal limbal epithelium.

Amniotic membrane inhibits squamous metaplasia of human conjunctival epithelium

Squamous metaplasia is a common pathological process that occurs in the ocular surface epithelium. At present, there is no effective treatment for this abnormality. In the current study, we established an ex vivo conjunctival squamous metaplasia model by culturing human conjunctival tissues at an air-liquid interface for durations of up to 12 days. We then investigated the effects of amniotic membrane (AM) on squamous metaplasia through coculture of conjunctival tissues with AM or AM extract. We found that metaplasia features such as hyperproliferation and abnormal epidermal differentiation of conjunctival epithelium could be inhibited by AM or its extract. In addition, existing squamous metaplasia of conjunctival epithelium could be reversed to a nearly normal phenotype by AM. The mechanism by which AM prevents squamous metaplasia may involve downregulation of p38 mitogen-activated protein kinase and Wnt signaling pathways, which were activated in conjunctival explants cultured with an airlift technique. In conclusion, AM can inhibit and reverse squamous metaplasia of conjunctival epithelium. This finding may shed new light on prevention and treatment of diseases that involve epithelial squamous metaplasia.

Truncated ErbB2 expressed in tumor cell nuclei contributes to acquired therapeutic resistance to ErbB2 kinase inhibitors

ErbB2 tyrosine kinase inhibitors (TKI) block tyrosine autophosphorylation and activation of the full-length transmembrane ErbB2 receptor (p185(ErbB2)). In addition to p185(ErbB2), truncated forms of ErbB2 exist in breast cancer cell lines and clinical tumors. The contribution of these truncated forms, specifically those expressed in tumor cell nuclei, to the development of therapeutic resistance to ErbB2 TKIs has not been previously shown. Here, we show that expression of a 95-kDa tyrosine phosphorylated form of ErbB2, herein referred to as p95L (lapatinib-induced p95) was increased in ErbB2(+) breast cancer cells treated with potent ErbB2 TKIs (lapatinib, GW2974). Expressed in tumor cell nuclei, tyrosine phosphorylation of p95L was resistant to inhibition by ErbB2 TKIs. Furthermore, the expression of p95L was increased in ErbB2(+) breast cancer models of acquired therapeutic resistance to lapatinib that mimic the clinical setting. Pretreatment with proteasome inhibitors blocked p95L induction in response to ErbB2 TKIs, implicating the role of the proteasome in the regulation of p95L expression. In addition, tyrosine phosphorylated C-terminal fragments of ErbB2, generated by alternate initiation of translation and similar in molecular weight to p95L, were expressed in tumor cell nuclei, where they too were resistant to inhibition by ErbB2 TKIs. When expressed in the nuclei of lapatinib-sensitive ErbB2(+) breast cancer cells, truncated ErbB2 rendered cells resistant to lapatinib-induced apoptosis. Elucidating the function of nuclear, truncated forms of ErbB2, and developing therapeutic strategies to block their expression and/or activation may enhance the clinical efficacy of ErbB2 TKIs.

[The morphology and thickness of cornea in patients with Marfan syndrome]

OBJECTIVE

To search for the characteristics of MFS in corneal morphology and thickness.

METHODS

Twenty-four patients (48 eyes) with MFS and 24 healthy age- and gender-matched volunteers (48 eyes) were recruited in this clinical prospective, and comparative series study. Firstly, biomicroscopic examination and Type-A ultrasonometry was conducted to search for ectopia lentis and axis length. Secondly, the corneal morphologic parameter [including the height of anterior and posterior surface, the centre corneal curvature, the mean astigmatism in the 3.0-mm central zone (Mean A), the mean simulated astigmatism (Sim A), the mean keratometry in the 3.0-mm central zone (Mean K), the mean simulated keratometry (Sim K), the 3.0-mm zone irregularity (3.0ZI), the 5.0-mm zone irregularity (5.0ZI), corneal thickness index (CTI)] and thickness (at the central location and at eight midperipheral locations) were obtained by the the autorefractometer and the Orbscan II Z corneal topography. Last, the statistics method including Crosstabs, One-way ANOVA, student-t test and discriminant analysis were applied and the correlations were established.

RESULTS

There is no statistically significance between MFS group and control group in ages (38 ± 7) and (37 ± 8) years, gender (8/16) and (9/15), and axis length (23.12 ± 1.06) mm and (24.26 ± 2.96) mm (age χ(2) = 0.091, P = 0.763;gender t = 0.324, axis length t = 1.976, P > 0.05). Flat cornea ratio (66.7% and 12.5%) and topography of the oval (25.0% and 16.7%), irregular bow-shaped (41.7% and 37.5%) and irregular-shaped (12.5% and 8.3%) were increased significantly in patients with MFS. The corneal topography (MFS/control) showed that there are statistically significance in the thinnest thickness of cornea (489.8 ± 42.9)µm and (544.8 ± 25.7)µm, Mean K (40.60 ± 1.30) D and (42.80 ± 1.40) D, Sim K (40.50 ± 1.30) D and (42.80 ± 1.20) D, Sim A (1.08 ± 0.86)D and (0.91 ± 0.46) D, CTI 1.57 ± 0.24 and 1.21 ± 0.14, 3.0ZI (1.76 ± 0.96) D and (1.54 ± 0.82) D, and 5.0ZI (1.91 ± 1.26) D and (0.92 ± 0.68) D (thinnest thickness t = 6.996, Mean K t = 2.554, Sim K t = 3.326, Sim A t = 2.324, CTI t = 3.116, 3.0ZI t = 2.686, 5.0ZI t = 3.768, P < 0.05), while no statistically significance in the Mean A between the MFS (1.11 ± 0.89) D and control group (0.99 ± 0.49) D (Mean A t = 1.898, P = 0.08); except for temple inferior, the significant decrease of pachymetry (including the center and the seven midperipheral locations) appeared in the MFS group compared with the control group.

CONCLUSION

The characteristic of MFS in corneal topography is that corneal axial refractive power descends and corneal thickness decreases.

Anti-angiogenic and anti-inflammatory effects of SERPINA3K on corneal injury

SERPINA3K is a member of the serine proteinase inhibitor (SERPIN) family. Here we evaluated the therapeutic effects of SERPINA3K on neovascularization and inflammation in a rat cornea alkali burn model that is commonly employed to study corneal wounding. Topical treatment of the injured rat cornea with SERPINA3K (20 µg/eye/day) for 7 days significantly decreased the neovascular area, compared with the groups treated with BSA or PBS. The SERPINA3K treatment also ameliorated the corneal inflammation as evaluated by the inflammatory index. Furthermore, SERPINA3K enhanced the recovery of corneal epithelium after the alkali injury. Toward the mechanism of action, SERPINA3K down-regulated the expression of the pro-angiogenic and pro-inflammatory factors, vascular endothelial growth factor and tumor necrosis factor-α and up-regulated the expression of the anti-angiogenic factor, pigment epithelium-derived factor. SERPINA3K specifically inhibited growth of vascular endothelial cells. Meanwhile, SERPINA3K significantly up-regulated the expression of EGFR in the corneal epithelium. These findings suggest that SERPINA3K has therapeutic potential for corneal inflammation and NV.

A mouse dry eye model induced by topical administration of benzalkonium chloride

PURPOSE

To develop a dry eye model of mouse induced by topical administration of benzalkonium chloride (BAC) and investigate the possible mechanisms.

METHODS

BAC at concentration of 0.2% was applied to the mouse ocular surface for 7 days. Phenol red thread tear test, tear break-up time (BUT) test, corneal inflammatory index scoring, fluorescein and rose bengal test were performed to evaluate the toxic effects of BAC on the ocular surface. Global specimens were collected on day (D) 7 and labeled with a series of antibodies including cytokeratin 10 (K10) and mucin 5AC (MUC5AC). Apoptosis of ocular surface epithelium was evaluated by in situ terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Histologic analysis and transmission electron microscopy (TEM) were performed on D7.

RESULTS

BAC at a concentration of 0.2% successfully induced a dry eye condition with decreased tear volume and BUTs, increased corneal fluorescein and rose bengal scores. The Inflammatory index was increased in accompaniment with higher tumor necrosis factor-α (TNF-α) expression and more inflammatory infiltration in the cornea. Immunolabeling revealed positive K10 expression in BAC-treated corneal epithelium and fewer MUC5AC-positive cells in the BAC-treated conjunctival fornix. TUNEL assay showed more apoptotic cells in the corneal basal epithelium. TEM showed that the size and intervals of the microvillis were both reduced in the corneal epithelium.

CONCLUSIONS

Topical administration of 0.2% BAC in mouse induces changes resembling that of dry eye syndrome in humans, and thus, represents a novel model of dry eye.

[Down-regulation of Pax6 in pterygial epithelium]

PURPOSE

To evaluate the expression of Pax6 in pterygia epithelium.

METHODS

Fifteen patients (15 eyes) with pterygium who underwent simple excision were enrolled in this study. Pax6, K10, K19 and MUC5AC immunostaining were performed in pterygia tissue and normal conjunctiva.

RESULTS

A decline or absence of Pax6 expression and K19 keratin and MUC5AC but increased of K10 expression with epidermal differentiation was observed in pterygia epithelium, in comparison with the normal conjunctival tissue.

CONCLUSIONS

These results indicate that down-regulation of Pax6 is associated with abnormal differentiation of the epithelial cells in pterygium.

[Preliminary investigation on tear film alterations in latent herpes stromal keratitis]

OBJECTIVE

To investigate tear film alterations in patients with latent herpes stromal keratitis (HSK).

METHODS

Prospective comparative case series study. Twenty-four patients with latent HSK in one eye and 28 age and gender matched healthy individuals were recruited. All subjects were evaluated by subjective symptoms of dry eye, tear film break-up time (BUT) and Schirmer I test (SIT). Laser in vivo confocal microscopic investigation was performed in 12 patients with severe tear film instability (BUT ≤ 5 s). Data distribution and homogeneity of variance was analyzed. Statistical comparisons of the mean values between different groups were performed using Kruskal-Wallis test, Mann-Whitney test or student t-test.

RESULTS

Most of latent HSK patients (n = 22/24, 91.7%) had symptoms as dryness, burning sensation, redness and foreign body sensation. Both eyes of patients with latent HSK had hyposecretion (SIT, control eyes (16.2 ± 3.2) mm/5 min; affected eyes (10.4 ± 7.8) mm/5 min; lateral eyes (11.2 ± 8.8) mm/5 min; control and affected, U = 135.0, P < 0.001; control and lateral, U = 155.0, P = 0.001) and decreased tear film stability [BUT, control eyes (12.1 ± 0.7) s, affected eyes (4.3 ± 3.3) s, lateral eyes (9.2 ± 4.4) s; control and affected, U = 28.0, P < 0.001; control and lateral, U = 114.0, P < 0.001] as compared to control group (Kruskal-Wallis nonparametric test). The value of BUT showed significant difference between affected eyes and healthy eyes (U = 90.0, P < 0.001), whereas no difference of the value of SIT was found (U = 273.0, P = 0.757). Abnormal SIT (≤ 10 mm/min) and BUT (≤ 10 s) was presented in 14 (58.3%) and 23 (95.8%) affected eyes, as well as in 14 (58.3%) and 17 (70.8%) lateral eyes, respectively. Laser in vivo confocal microscopy investigation in 12 affected corneas with abnormal tear film showed morphological alterations as corneal epithelial metaplasia with polymorphism and enlarged cells, reflective nuclei, and decreased nucleus/cytoplasm ratio; decreased nerve density in subepithelial plexus and obvious branching and beading, which is similar to those changes caused by dry eye.

CONCLUSIONS

Most of latent HSK patients had abnormal tear film. Dry eye related alterations could be found in affected corneas with abnormal tear film by in vivo confocal microscopy.

[Focus on the challenge of basic research on corneal tissue engineering]

Great progress has been made on the corneal tissue engineering in the past two decades. Much knowledge has been gained on the seed cells, carrier material, and strategies of corneal tissue reconstruction. However, there are still great challenges regarding the basic research of corneal tissue engineering, such as selection of appropriate carrier and cells, optimization and standardization of the construction method, and evaluation of the clinic outcome. Future studies may address these questions and bring tissue engineered cornea into clinic application.

Mutation analysis of CHST6 gene in Chinese patients with macular corneal dystrophy

PURPOSE

To examine the carbohydrate sulfotransferase 6 (CHST6) gene in Chinese patients with macular corneal dystrophy (MCD).

METHODS

Nineteen unrelated Chinese families with MCD, including 24 patients and 3 unaffected relatives, were examined. Genomic DNA was extracted from peripheral blood leukocytes. The coding region of the CHST6 gene was amplified by the polymerase chain reaction, and the DNA fragments were directly sequenced. Fifty unrelated normal Chinese volunteers served as the controls.

RESULTS

Eighteen different mutations in the CHST6 gene (including 15 novel mutations) were identified, of which 12 were missense mutations, 5 were nonsense mutations, and 1 was a frameshift mutation. Six families had homozygous mutation, and 13 families had compound heterozygous mutation. None of these mutations were detected in the normal controls.

CONCLUSIONS

CHST6 mutations may be responsible for the pathogenesis of MCD in Chinese patients. The Q298X mutation detected in 5 of 19 families (6 of 38 alleles, 15.8%) may be the founder mutation in Chinese patients. However, our findings also indicate a high level of allelic heterogeneity of the CHST6 gene in Chinese patients and in other ethnic groups.

Novel anti-apoptotic mechanism of A20 through targeting ASK1 to suppress TNF-induced JNK activation

The zinc-finger protein A20 has crucial physiological functions as a dual inhibitor of nuclear factor-κB (NF-κB) activation and apoptosis in tumor necrosis factor (TNF) receptor 1 signaling pathway. Although the molecular basis for the anti-NF-κB function of A20 has been well elucidated, the anti-apoptotic function of A20 is largely unknown. Here, we report a novel mechanism underlying the anti-apoptotic function of A20: A20 blocks TNF-induced apoptosis through suppression of c-jun N-terminal kinase (JNK) by targeting apoptosis signal-regulating kinase1 (ASK1). First, the ectopic expression of A20 drastically inhibits TNF-induced JNK activation and apoptosis in multiple cell types including those deficient of NF-κB activation. Unexpectedly, the blunting effect of A20 on TNF-induced JNK activation is not mediated by affecting the TNFR1 signaling complex formation. Instead, A20 interacts with ASK1, an important MAPKK kinase in the JNK signaling cascade. More importantly, overexpression of wild-type A20, but not of mutant A20 (ZnF4; C624A, C627A), promotes degradation of the ASK1 through the ubiquitin-proteasome system. Taken together, the results from this study reveal a novel anti-apoptotic mechanism of A20 in TNF signaling pathway: A20 binds to ASK1 and mediates ASK1 degradation, leading to suppression of JNK activation and eventually blockage of apoptosis.

MLL-AF9-induced leukemogenesis requires coexpression of the wild-type Mll allele

Oncogenic fusion proteins are capable of initiating tumorigenesis, but the role of their wild-type counterparts in this process is poorly understood. The mixed lineage leukemia (MLL) gene undergoes chromosomal translocations, resulting in the formation of oncogenic MLL fusion proteins (MLL-FPs). Here, we show that menin recruits both wild-type MLL and oncogenic MLL-AF9 fusion protein to the loci of HOX genes to activate their transcription. Wild-type MLL not only catalyzes histone methylation at key target genes but also controls distinct MLL-AF9-induced histone methylation. Notably, the wild-type Mll allele is required for MLL-AF9-induced leukemogenesis and maintenance of MLL-AF9-transformed cells. These findings suggest an essential cooperation between an oncogene and its wild-type counterpart in MLL-AF9-induced leukemogenesis.

Resistance to ErbB2 tyrosine kinase inhibitors in breast cancer is mediated by calcium-dependent activation of RelA

The widespread clinical use of therapies targeting the ErbB2 receptor tyrosine kinase oncogene represents a significant advance in breast cancer treatment. However, the development of therapeutic resistance represents a dilemma limiting their clinical efficacy, particularly small-molecule tyrosine kinase inhibitors that block ErbB2 autophosphorylation and activation. Here, we show that lapatinib (GW572016), a highly selective, small-molecule inhibitor of the ErbB2 and epidermal growth factor receptor tyrosine kinases, which was recently approved for the treatment of advanced-stage ErbB2(+) breast cancer, unexpectedly triggered a cytoprotective stress response in ErbB2(+) breast cancer cell lines, which was mediated by the calcium-dependent activation of RelA, the prosurvival subunit of NF-kappaB. Abrogation of lapatinib-induced RelA activation using either small interfering RNA constructs or an intracellular calcium chelator enhanced the apoptotic effects of lapatinib in parental ErbB2(+) breast cancer cells and overcame therapeutic resistance to lapatinib in ErbB2(+) breast cancer lines that had been rendered resistant to lapatinib through chronic exposure to the drug, mimicking the clinical setting. In addition, analysis of changes in phospho-RelA expression in sequential clinical biopsies from ErbB2(+) breast cancers treated with lapatinib monotherapy revealed marginally statistically significant differences between responders and nonresponders, which was consistent with our preclinical findings. Elucidating the regulation of RelA by lapatinib in ErbB2(+) breast cancers, and showing its role in the development of therapeutic resistance to lapatinib, identifies another therapeutic target to overcome or prevent the onset of resistance to lapatinib in some women with ErbB2(+) breast cancers.

[Effects of benzalkonium chloride on MUC1 in human conjunctival epithelial cells]

OBJECTIVE

To investigate the effects of benzalkonium chloride (BAC), a preservative used in many ophthalmic topical solutions, on mucin1 (MUC1) in human conjunctival epithelial cells in vitro.

METHODS

Cultured epithelial cells obtained from human conjunctiva were exposed to medium containing BAC solutions at 0.0100%, 0.0050%, 0.0010%, 0.0005% and 0.0001% concentrations for a period of 15 min. Cells were examined after treatment and 6, 12, 24, 48 and 72 h later. The relative expression of the MUC1 mucin gene was determined by conventional reverse transcription-polymerase chain reaction (RT-PCR). Monoclonal antibody for MUC1 was used in Western blot analysis to detect MUC1.

RESULTS

Cell exposure to 0.0100% and 0.0050% BAC decreased the expression of MUC1 at gene level between 12 and 72 h after treatment. Cells treated with 0.0010% and 0.0005% BAC decreased the expression of MUC1 between 24 and 48 h after treatment, recovered 72 h after treatment. At protein level, cells exposed to 0.0100% BAC decreased MUC1 between 24 and 72 h, 0.0050% BAC between 12 and 72 h, 0.0010% BAC 72 h later.

CONCLUSIONS

These results suggest that BAC induces decreased expression of MUC1 at both gene and protein levels. The mode of BAC-induced decreased expression of MUC1 is dose-dependent.

Influence of environmental characteristics and climatic factors on mites in the dust of air-conditioner filters

To investigate mites in the dust of air-conditioner filters (MACF) in China, a total of 652 dust samples were collected from six cities: Guangzhou (n = 129), Nanchang (n = 127), Shanghai (n = 113), Xian (n = 93), Beijing (n = 93), and Shenyang (n = 79). Tarsonemus granarius was the most dominant species (87.2%). Dermatophagoides pteronyssinus and Dermatophagoides farinae only represented 7.0 and 3.0% of total mites, respectively. With latitude increasing, both mite occurrence rate (P < 0.001) and density (mites/g dust) (P < 0.001) were significantly decreasing. Multivariate regression analysis suggested that the annual average temperature and minimum temperature in different cities had dominant influences on MACF density. The logistic regression analysis revealed that the presence of MACF was positively associated with air-conditioner age, utilization time and power. Wall and window type air-conditioner had higher risk of finding MACF than the floor type air-conditioner. As far as the cleaning interval time of ACF was concerned, higher risk ratio and the highest density of MACF were found in the time stage of >3, < or =12 months. It was also suggested that house type could influence the presence of MACF. A negative association between the house floor and the MACF prevalence was found as well.

PRACTICAL IMPLICATIONS

Mites present in the dust of air-conditioner filters are potential indoor threat to asthma and allergy sufferers. In this study, we find that the storage mite Tarsonemus granarius is the predominant species of mites in the dust of air-conditioner filters (MACF). Thus, the possible clinical importance of T. granarius should cause more our attentions in the future. The abundance and distribution of MACF are also found significantly varied in different climatic regions of China. When we try to assess the possible risk of MACF, more attentions should be focused on subtropical region than temperate region. The influence analysis of environmental characteristics on the prevalence of MACF will shed light on the establishment of mite control strategy and the design of mite defense air-conditioner.