Isolation and characterization of rabbit limbal niche cells.

Limbal niche cells (LNCs) are one of the most important supporting cells for corneal epithelial stem cells (CES), however, research on LNCs has been mostly limited to humans and rats previously. To expand the research work into the rabbit animal model, one of the most often used animals in stem cell study, this study was carried out for the in vitro isolation and identification of rabbit LNCs. Rabbit LNCs were isolated by collagenase A digestion method and single cells were obtained, the cells were then seeded on 5% Matrigel-coated plastic surface and cultured in modified embryonic stem cell medium (MESCM). Three biological replicates of the isolating and characterization were recorded from New Zealand White rabbits aged from 2.5 months to 5 months. LNC markers (VIM/CD90/CD105/SCF/PDGFRß) were analyzed using tyramide signal amplification (TSA) staining, immunohistochemical staining (IHC), western blotting (WB), and real-time reverse transcription polymerase chain reaction (qPCR). TSA staining suggested that VIM was highly expressed in rabbit limbus stroma, which was confirmed by WB, and P63α was expressed in the basal limbus epithelium. Pan-CK and CK12 were highly expressed in the central corneal epithelium but lightly expressed in the limbal epithelium. The WB result indicated that PDGFRß and VIM expressions in rabbit-LNCs P4 were higher than in P1 and P7. In addition, rabbit corneal epithelium highly expressed Paired Box 6 (PAX6) and Epidermal growth factor-like domain 6(EGFL6). For the three repeat experiments, the cell expansion activity of rabbit-LNC was highest at P4. Rabbit-LNCs were passaged from P0 to P7, and the number of cell doublings (NCD) of P4 for the three repeat experiments was 2.816, 2.737, and 2.849. qPCR showed that high mRNA expression levels of VIM, CD90, CD105, SCF, and PDGFRß in rabbit-LNCs P4. In conclusion, rabbit-LNCs could be successfully isolated by the collagenase A digestion method as used in human tissue. There were similar characteristics between rabbit and human LNCs (VIM+/CD90+/CD105+/SCF+/PAX6+/PDGFRß+).

Differential Gene Expression between Limbal Niche Progenitors and Bone Marrow Derived Mesenchymal Stem Cells.

Purpose: To compare the difference in gene expression between human limbal niche cells (LNC) and bone marrow derived mesenchymal stem cells (BMMSC). Methods: LNC were isolated by collagenase and expanded in modified embryonic stem cell medium (MESCM) on a Matrigel coated plastic plate. Cell diameters were measured with Image J software. Relative gene expression levels between LNC and BMMSC were compared using Affymetrix Human Primer View Gene Expression Array. A subset of differentially expressed genes was verified by RT-qPCR. The protein level of LAMA1 and COL4A1 was confirmed by Western blot and immunostaining. Results: The average diameter of LNC was 10.2±2.4 µm, which was significantly smaller than that of BMMSC (14 ±3.4 µm) (p<0.0001). Expression of 20,432 genes was examined by Gene Expression Array, among which expression of 349 genes in LNC was 10-fold or higher than that of BMMSC and expression of 8 genes in LNC was 100-fold or higher than that of BMMSC, while expression of 3 genes in BMMSC was 100-fold higher than that of LNC. GO analysis and pathway analysis showed that the differentially expressed genes were mainly enriched in the extracellular matrix receptor interaction pathway and Wnt signaling pathway. In addition, RT-qPCR results demonstrated that the expression of CD73, CD90, CD105, PDGFRß, Vimentin, SCF, KIT (CD117), COL14A1, LAMA2, THBS2, FZD1, BMP2 and CXCL12 genes in LNC were at least 2 folds higher than BMMSC. The protein level of LAMA1 was higher but the protein level of COL4A1 was lower in LNC than that in BMMSC. Conclusion: LNC exhibit differential gene expression from BMMSC in the extracellular matrix (ECM) receptor interaction pathway and Wnt signaling pathway, suggesting that LNC have their unique signaling pathways to support limbal stem cell niches.

Eye drops and eye gels of levofloxacin: comparison of ocular absorption characterizations and therapeutic effects in the treatment of bacterial keratitis in rabbits.

The aim was to reveal the characteristic profiles of the marketed levofloxacin eye drops (5 mg/ml) and levofloxacin eye gel (3 mg/g) from the pharmacokinetics and pharmacodynamics views of rabbits' eyes. A mild and a heavy bacterial keratitis models in rabbits were established. Different regimens of levofloxacin eye drops and eye gel, including phosphate buffer solution (the PBS group), the 4-Sol + 1-Gel group (rabbits were treated with 4 doses of levofloxacin eye drops and 1 dose levofloxacin eye gel per day), the 3-Sol + 1-Gel group (3 doses drops and 1 dose gel), the 4-Sol group (4 doses drops), the 4-Gel group (4 doses gel), the 3-Sol group (3 doses drops), and the 3-Gel group (3 doses gel), were applied to evaluate their efficacies. The ocular pharmacokinetics of levofloxacin eye drops and gel were also investigated. The results of mild infection groups showed that all treatment regimens significantly relieved the infection symptoms, and the treatment effect followed this order: 4-Gel > 4-Sol + 1-Gel > 3-Sol + 1-Gel > 4-Sol > 3-Gel > 3-Sol. In the heavy infection groups, all the treatment regimens significantly relieved the infection symptoms, and the treatment effect also followed the order with the mild infection results. All treatment regimens lowered the number of corneal colony forming units (CFU). Levofloxacin eye gel significantly increased intraocular penetration in rabbits' eyes. It can be concluded that the levofloxacin eye gel was more effective in treating bacterial keratitis than the levofloxacin eye drops in rabbit keratitis model with a proper treatment regimen such as 4-Gel.

Expansion and maintenance of primary corneal epithelial stem/progenitor cells by inhibition of TGFß receptor I-mediated signaling.

Transforming growth factor ß (TGFß) signaling is one of the most important signaling pathways regulating cell behavior in ocular tissues. Its functions are mainly linked to tissue fibrosis and inflammatory responses in ophthalmology. In epithelial cells, however, the growth inhibitory activity of TGFß was reported in both non-ocular and ocular tissues. Since TGFß is a bifunctional regulator that either inhibits or stimulates cell proliferation according to the specific context, we examined the effect of inhibition of TGFß receptor (TßR) I-mediated signaling on primary corneal epithelial cells (CECs) in serum- and feeder-free conditions. The mouse CECs were isolated from the eyeballs of 6-8 weeks old female C57BL/6 mice using dispase and trypsin separately, cultivated in defined Keratinocyte serum-free medium (KSFM) with supplements (the complete medium) without feeder layer. Cells were divided into three groups, those cultured in complete medium additionally supplemented with 10 µM SB-431542, a specific inhibitor of TßR-I, were SB-CECs; those cultured in complete medium additionally supplemented with 10 ng/ml SRI-011381, a TGF-beta signaling agonist, were SRI-CECs; those cultured in complete medium without SB-431542 or SRI-011381 were control CECs. The growth rate and morphology were analyzed by light microscopy. The identity and stemness of cells was investigated through marker staining of p63, inhibitor of differentiation 1 (ID1), cytokeratin 12 (K12), cytokeratin 14 (K14), PAX6, pSmad3, alpha smooth muscle Actin (αSMA) and E-cadherin (E-cad); Real-time quantitative (RT-PCR) analysis of p63; Western blot analysis of ID1; as well as colony forming assay, sphere forming assay, healing wound in vitro assay and air-lifting interface assay. The results showed SB-CECs subcultured steadily, achieved sustained expansion, and expanded almost thrice faster than control CECs. Expanded SB-CECs exhibited smaller and more compact morphology, up-regulated p63 and ID1, as well as better performed colony-forming capacity, sphere-forming capacity, in vitro wound healing capacity, and the capacity to stratify and differentiate on air-lifting interface. Preliminary tests on human limbal epithelial cells (HLECs) showed the same results as mouse CECs. Interestingly, the ID1 expression pattern was almost identical to p63, the typical marker for corneal epithelial stem/progenitor cell (CESC/CEPC), in cultured CECs and normal corneal sections. Since ID1 has been proven to be regulated negatively by TGFß signaling in epithelial cells and plays a role in blocking cell differentiation, its derepression by TßR-I inhibitor could be, at least in part, the underlying cause of CESC/CEPC expansion and the synchronously up-regulated expression of p63 in SB-CECs. In conclusion, inhibition of TßR-I-mediated signaling, CESCs/CEPCs achieved efficient long-term expansion in a feeder- and serum-free condition in vitro. And derepression of ID1 could be the underlying cause. Meanwhile, ID1 could serve as a marker for CESC/CEPC. These results may advance the basic and clinical CESC/CEPC research.

Efficacy of Anterior Stromal Puncture Surgery with Corneal Bandage Lens for Bullous Keratopathy.

Objective: To investigate the safety and efficacy of the combination therapy of anterior stromal puncture (ASP) with bandage contact lens for bullous keratopathy (BK). Methods: Twelve cases (12 eyes) with vision acuity no better than light perception were treated with ASP surgery and bandage contact lens. 200 points punctures were made through the corneal epithelium and Bowman's layer vertically, using fine needles. A soft bandage contact lens was applied immediately and removed 2 weeks later. The severity of irrigating symptoms including pain, photophobia and tearing was graded and calculated before treatment and 1, 2, 4, 12 weeks after the surgery, slit-lamp microscope examination was used to quantify the time for corneal epithelial blisters disappearing, optical coherence tomography (OCT) was used to monitor the central corneal thickness. Results: No cornea infection was observed during the following up period. The average grade scores of the irrigating symptoms was 8.3 ± 2.1 before surgery, while it was reduced to 4.8 ±1.9 two weeks after the surgery (p=0.0003). Slit-lamp microscope examination showed that corneal edema relieved obviously after the operation, the average time for epithelial blisters disappearing was 15.6 ± 4.0 days. The average central corneal thickness of the eyes was 999.3 ±278.0 µm before the treatment, while it was 805.1 ± 145.0 µm four weeks after the treatment, with a statistically significant difference (p=0.043). Conclusions: ASP with bandage contact lens is an effective and safe treatment for patients with BK and low vision that not suitable for corneal transplantation.

Availability of benzathine penicillin G for syphilis treatment in Shandong Province, Eastern China.

BACKGROUND: The shortage of benzathine penicillin G (BPG) worldwide presents a major challenge in the treatment of syphilis. Its availability for syphilis treatment has not been adequately evaluated in China. METHODS: Two surveys were conducted among hospitals providing sexually transmitted infection clinical services in Shandong Province in 2012 and 2018. Data on the basic information and BPG availability of the surveyed hospitals and related factors were collected and analyzed using SPSS 17.0. RESULTS: A total of 433 and 515 hospitals were surveyed in 2012 and 2018, respectively. A significant difference in BPG availability was observed among different levels and types of hospitals both in 2012 (X2 = 9.747, p = 0.008; X2 = 37.167, p = 0.000) and 2018 (X2 = 11.775, p = 0.003; X2 = 28.331, p = 0.000). The BPG availability among surveyed hospitals increased from 45.0% in 2012 to 56.4% in 2018 (X2 = 11.131, p = 0.001). The BPG availability was higher in 2018 than in 2012 among county-level hospitals (52.0% vs. 40.8%, X2 = 7.783, p = 0.005), general western medicine hospitals (62.1% vs. 50.0%, X2 = 6.742, p = 0.009), maternal and child health hospitals (57.1% vs. 26.9%, X2 = 13.906, p = 0.000), and public hospitals (56.8% vs. 45.0%, X2 = 11.361, p = 0.001). However, the county-level availability of BPG (at least one hospital has BPG in a county-level unit) has not improved between 2012 and 2018 (65.93% vs. 70.34%; X2 = 0.563, p = 0.453). The absences of clinical needs, restriction of clinical antibacterial drugs, and lack of qualifications for providing syphilis treatment were the major reasons for the low BPG availability of hospitals. CONCLUSIONS: BPG availability for syphilis treatment in Shandong Province remains low and presents disparities among different levels and types of hospitals, although it has been improved in recent years. The low availability of BPG for syphilis treatment in China is related to its clinical use by doctors rather than the market supply. Health care reforms should further improve the availability and accessibility of health services.

Microbiological contamination in donor corneas preserved for medium-term.

To evaluate the characteristics of microbiological contamination in donor corneas preserved for medium-term. A total of 82 donated corneas from June 1, 2014 to November 30, 2014 were retrospectively analyzed. The corneas were preserved in cornea chambers medium-term solution at 4-8 °C for keratoplasty. After removal of the central corneas for transplantation, the corneoscleral rims were put back into the medium for 1 month at room temperature (20-25 °C). The suspicious contaminated storage solutions indicated with transparency or color change were examined with bacteria and fungi cultivation for strain identification. The data collected included gender, age, procurement site and causes of death of donors, and follow-up of recipients. Statistical analysis was performed using Microsoft Excel and SPSS 24.0. Significance level was set at a P value < 0.05. The overall pathogen positive rate was 9.8% (n = 8), including 7 (87.5%) fungi and 1 (12.5%) bacteria. They were 2 (2.44%) Fusarium, 2 (2.44%) Chromomycosis, 1 (1.22%) Candida albicans, 1 (1.22%) Aspergillus versicolor, 1 (1.22%) Acremonium species, and 1 (1.22%) Enterococcus. 5 contaminated corneas were used for penetrating keratoplasty; although four out of five (80%) had not been given antifungal drugs during more than 6 months following-up period, none of the recipients was infected with a graft. Donor age (P = 0.839), gender (P = 0.062), procurement sites (P = 0.713) and cause of death (P = 0.711) had no statistically significant influence on the contamination rate. All donor corneas have a possibility of microbiological contamination. Strict tissue preservation protocol but not antifungal drugs following keratoplasty seems necessary to prevent graft infection.

A New Isolation Method of Human Lacrimal Canaliculus Epithelial Stem Cells by Maintaining Close Association with Their Niche Cells.

Purpose: To investigate whether lacrimal canaliculus epithelial stem cells (LCESC) could be isolated and expanded in vitro. Methods: The lacrimal canaliculus epithelium of 6 patients with limbal stem cell deficiency (LSCD) caused by alkali burn or Stevens Johnson Syndrome were examined by lacrimal endoscope. Cadaveric eyelids were fixed and prepared for cross section and stained with HE and antibodies against PCK, Vim, p63α, SCF and c-Kit. Canaliculus tissue was separated under an operating microscope using a lacrimal probe as an indicator and digested with collagenase A. The clusters of epithelial cells with closely associated stroma were further digested with Trypsin/EDTA to obtain single cells for culture on Matrigel-coated plastic plates in MESCM media. The expression of SCF, c-Kit and p63α was determined by immunostaining. The colony-forming efficiency on 3T3 feeder layers was also measured by calculating the percentage of the clone number divided by the total number cells seeded. Results: The epithelial layers of five out of six inferior lacrimal canaliculi and all the six superior lacrimal canaliculi were visually normal in appearance. Five to fifteen layers of the epithelium in the human lacrimal canaliculi were present with a small, tightly compacted basal layer of cells expressing PCK, p63α, SCF and c-Kit. LCESC were isolated by collagenase A and obtained clonal growth in MESCM. The colony-forming efficiency of LCESC holoclones on a 3T3 feeder layer was 3.2%, compared to 1.9% for those of limbal stem cells (LSC). Conclusions: Herein, we first report that LCESCs can be isolated and have stem cell characteristics, similar to those of LSCs. Such a discovery raises a promising substrate resource of stem cells for LSC reconstruction in LSCD patients.

Lacrimal Duct Occlusion Is Associated with Infectious Keratitis.

Background: To explore the prevalence of lacrimal duct obstruction in patients with infectious keratitis, and the necessity of lacrimal duct dredge in the treatment of human infectious keratitis. Methodology/Principle Findings: The design is prospective, non-control case series. Thirty-one eyes from twenty-eight continuous patients with infectious keratitis were included in this study. The presence/absence of lacrimal duct obstruction was determined by the lacrimal duct irrigation test. The diagnosis of infectious keratitis was made based on clinical manifestations, cornea scraping microscopic examination and bacterial/fungus culture. Diagnosis of viral keratitis was set up based on the recurrent history, deep neovascularization and typical outlook of the cornea scar. The treatment of keratitis included drugs, eye drops or surgery, while treatment of chronic dacryocystitis was lacrimal duct dredging with supporting tube implantation surgery. In the thirty-one eyes with infectious keratitis, fifteen suffered from fungal keratitis (48%), two bacterial keratitis (6%), and fourteen viral keratitis (45%). Eleven eyes (35%) from ten patients with infectious keratitis also suffered from lacrimal duct obstruction. In those cases, six eyes also suffered from lower canalicular obstruction, three nasolacrimal duct obstruction and chronic dacryocystitis, one a combination of upper and lower canalicular obstruction, one upper canalicular obstruction. After local and systemic applications of anti-bacterial, anti-viral, anti-fungal and anti-inflammatory drugs, twenty-eight eyes (90%) recovered within three weeks, while the ulceration of three patients required the lacrimal duct dredging and supporting tube implantation surgery for the healing. Conclusions: Herein, we first report that the prevalence of infectious keratitis is closely correlated to the occurrence of lacrimal duct obstruction. When both confirmed, simultaneous treatment of keratitis and lacrimal duct obstruction promptly is required. Further evaluation of mechanism, prevention and control of the diseases are warranted.

The role of long noncoding RNAs in ocular angiogenesis and vascular oculopathy.

BACKGROUND: Long noncoding RNAs (lncRNAs) are RNA transcripts over 200 nucleotides in length that do not code for proteins. Initially considered a genomic mystery, an increasing number of lncRNAs have been shown to have vital roles in physiological and pathological conditions by regulating gene expression through diverse mechanisms depending on their subcellular localization. Dysregulated angiogenesis is responsible for various vascular oculopathies, including diabetic retinopathy, retinopathy of prematurity, age-related macular degeneration, and corneal neovascularization. While anti-VEGF treatment is available, it is not curative, and long-term outcomes are suboptimal, and some patients are unresponsive. To better understand these diseases, researchers have investigated the role of lncRNAs in regulating angiogenesis and models of vascular oculopathies. This review summarizes recent research on lncRNAs in ocular angiogenesis, including the pro-angiogenic lncRNAs ANRIL, HOTAIR, HOTTIP, H19, IPW, MALAT1, MIAT, NEAT1, and TUG1, the anti-angiogenic lncRNAs MEG3 and PKNY, and the human/primate specific lncRNAs lncEGFL7OS, discussing their functions and mechanisms of action in vascular oculopathies.

Safety and Efficacy of Dry Eye Intelligent Therapeutic Device in the Treatment of Meibomian Gland Dysfunction in Rabbits.

PURPOSE: To assess the safety and efficacy of the dry eye intelligent therapeutic device in rabbits with meibomian gland dysfunction. METHODS: The meibomian gland dysfunction-afflicted rabbits were subjected to treatment using the dry eye intelligent therapeutic device. Various parameters, including eyelid margin, meibomian gland opening, redness, meibomian gland area, keratoconjunctival fluorescence staining, and intraocular pressure, were examined and analyzed using an ocular surface comprehensive examination instrument, slit lamp, and tonometer at corresponding times points. Hematoxylin and eosin staining was performed to examine the mucosal epithelium and meibomian gland. RESULTS: In this study, eyelid margin congestion and meibomian gland opening obstruction were significantly improved after 3 weeks and 4 weeks of treatment, respectively (p < .01, p < .05). The treatment group showed a significant increase in tear meniscus height after 2 weeks, 3 weeks and 4 weeks of treatment (p < .001, p < .01, p < .05). No significant changes were noted in meibomian gland area, redness, intraocular pressure, and keratoconjunctival fluorescence staining of rabbits before and after treatment. Hematoxylin and eosin staining revealed a complete structure of mucosal epithelium and meibomian gland in the treatment group and that the expansion of the blocked meibomian gland duct was reduced. CONCLUSION: The utilization of the dry eye intelligent therapeutic device in treating meibomian gland dysfunction-afflicted rabbits exhibits potential promising safety, efficacy, and overall benefits, thereby offering a novel alternative for managing meibomian gland dysfunction patients in clinical settings.

The single-cell transcriptomic atlas and RORA-mediated 3D epigenomic remodeling in driving corneal epithelial differentiation.

Proper differentiation of corneal epithelial cells (CECs) from limbal stem/progenitor cells (LSCs) is required for maintenance of ocular homeostasis and clear vision. Here, using a single-cell transcriptomic atlas, we delineate the comprehensive and refined molecular regulatory dynamics during human CEC development and differentiation. We find that RORA is a CEC-specific molecular switch that initiates and drives LSCs to differentiate into mature CECs by activating PITX1. RORA dictates CEC differentiation by establishing CEC-specific enhancers and chromatin interactions between CEC gene promoters and distal regulatory elements. Conversely, RORA silences LSC-specific promoters and disrupts promoter-anchored chromatin loops to turn off LSC genes. Collectively, our work provides detailed and comprehensive insights into the transcriptional dynamics and RORA-mediated epigenetic remodeling underlying human corneal epithelial differentiation.

The hiPSC-derived corneal endothelial progenitor-like cell recovers the rabbit model of corneal endothelial dystrophy.

INTRODUCTION: Corneal endothelial dysfunction results in cornea opacity, damaging sightedness, and affecting quality of life. A corneal transplant is the current effective intervention. Due to the scarcity of donated cornea, such an unmet medical need requires a novel therapeutic modality. OBJECTIVES: Customizing patients' corneal endothelial progenitor cells with proliferative activity and lineage restriction properties shall offer sufficient therapeutic cells for corneal endothelial dystrophy. METHODS: The customized induced human corneal endothelial progenitor-like cell (iHCEPLC) was obtained through cell fate conversions starting from PBMC (peripheral blood mononuclear cell), hiPSC (human induced pluripotent stem cell), and hNCC (human neural crest cell), while it finally reached the iHCEPLC state via a series of induction. Several molecular diagnoses were applied to depict its progenitor state, including RNAseq, FlowCytometer, immunostainings, and rtPCR. Significantly, it can be induced to gain differentiation maturity through contact inhibition. In addition, a BAK-mediated rabbit model of corneal endothelial dystrophy was established in the present study to test the therapeutic effectiveness of the iHCEPLC. RESULTS: After inducing cell fate conversion, the specific HCEC markers were detected by rtPCR and immunostaining in iHCEPLC. Further, RNAseq was applied to distinguish its progenitor-like cell fate from primary human corneal endothelial cells (HECE). FlowCytometry profiled the heterogeneity subpopulation, consistently displaying a subtle difference from primary HCEC. A terminal differentiation can be induced in iHCEPLC, addressing its progenitor-like fate. iHCEPLC can restore the BAK-based rabbit model of corneal endothelial dystrophy. Immunohistochemistry verified that such acuity restoration of the BAK-treated cornea is due to the introduced iHCEPLC, and such therapeutic effectiveness is observed in the long term. CONCLUSION: Here, we demonstrated that customized iHCEPLC has long-term therapeutic efficacy. As a progenitor cell, our iHCEPLC has a restricted cell lineage nature and can proliferate in vitro, supporting sufficient therapeutic candidate cells. Due to the immune-privileged nature of the cornea, our iHCEPLC proves the principle of therapeutical feasibility in both autogenic and allogeneic modalities.

Isolation and Identification of Limbal Niche Cells.

Here we report a standard procedure for the isolation and identification of limbal niche cells (LNCs). Limbus tissue obtained from an eye bank was used for LNCs isolation. The tissue was divided into 12 pieces under aseptic conditions and digested for 18 h at 37 °C in the cell culture incubator using collagenase A to obtain cell clusters with LNCs and limbal epithelial progenitor cells. The cell clusters were further digested for 15 min at 37 °C using 0.25% trypsin-EDTA to obtain single cells and then cultured in modified embryonic stem cell medium (MESCM) on a plastic surface coated with 5% Matrigel. Cells were passaged upon 70% confluence, and LNCs were identified using immunofluorescence, real-time quantitative PCR (qPCR), and flow cytometry. Primary LNCs were isolated and passaged more than 12 times. The proliferation activity of LNCs from P4 to P6 was the highest. LNCs expressed higher stem cell markers than BMMSCs (SCF, Nestin, Rex1, SSEA4, CD73, CD90, MSX1, P75NTR, and PDGFRß). Furthermore, results showed that P4 LNCs uniformly expressed VIM, CD90, CD105, and PDGFRß, but not Pan-CK, which could be used as a marker for the identification of LNCs. Flow cytometric analysis showed that approximately 95%, 97%, 92%, and 11% of LNCs expressed CD73, CD90, CD105, and SCF respectively, while they were 68%, 99%, 20%, and 3% in BMMSCs. The standard process for LNC isolation and identification could provide a reliable laboratory basis for the widespread use of LNCs.

Diagnosis of fungal keratitis caused by Nectria haematococca through next-generation sequencing: review of literature and report of three cases.

OBJECTIVES: Fungal keratitis (FK) is a kind of serious corneal infection and penetrating keratoplasty (PKP) is needed when medical therapy fails. Although Nectria haematococca is found as endophytes in the roots of some plant species, there has been no report of N. haematococca infection in human. METHODS: We reviewed 46 patients who underwent PKP due to FK in our hospital from July 2021 to December 2021, and there were three patients who had relapsed. The next-generation sequencing revealed that all three corneas were infected with N. haematococca. RESULTS: Based on the ocular manifestation and treatment course of three cases, we summarize the characteristics of N. haematococca FK: the scope of corneal infection was widespread with severe hypopyon. The effect of local use of fluconazole and voriconazole was not ideal, and PKP was the main treatment. Even after a large-scale corneal lesion resection, the lesion may recur. The recurrence occurred primarily in the second week after PKP. CONCLUSION: This is the first clinical report of N. haematococca infection in humans. Compared with the other currently known FK caused by the Fusarium solani species complex, N. haematococca keratitis is more severe and more likely to recur.

Development and multi-center validation of machine learning model for early detection of fungal keratitis.

BACKGROUND: Fungal keratitis (FK) is a leading cause of corneal blindness in developing countries due to poor clinical recognition and laboratory identification. Here, we aimed to identify the distinct clinical signature of FK and develop a diagnostic model to differentiate FK from other types of infectious keratitis. METHODS: We reviewed the electronic health records (EHRs) of all patients with suspected infectious keratitis in Beijing Tongren Hospital from January 2011 to December 2021. Twelve clinical signs of slit-lamp images were assessed by Lasso regression analysis and collinear variables were excluded. Three models based on binary logistic regression, random forest classification, and decision tree classification were trained for FK diagnosis and employed for internal validation. Independent external validation of the models was performed in a cohort of 420 patients from seven different ophthalmic centers to evaluate the accuracy, specificity, and sensitivity in real world. FINDINGS: Three diagnostic models of FK based on binary logistic regression, random forest classification, and decision tree classification were established and internal validation were achieved with the mean AUC of 0.916, 0.920, and 0.859, respectively. The models were well-calibrated by external validation using a prospective cohort including 210 FK and 210 non-FK patients from seven eye centers across China. The diagnostic model with the binary logistic regression algorithm classified the external validation dataset with a sensitivity of 0.907 (0.774, 1.000), specificity 0.899 (0.750, 1.000), accuracy 0.905 (0.805, 1.000), and AUC 0.903 (0.808, 0.998). INTERPRETATION: Our model enables rapid identification of FK, which will help ophthalmologists to establish a preliminary diagnosis and to improve the diagnostic accuracy in clinic. FUNDING: The Open Research Fund from the National Key Research and Development Program of China (2021YFC2301000) and the Open Research Fund from Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beijing Tongren Hospital, Beihang University &Capital Medical University (BHTR-KFJJ-202001) supported this study.

3% diquafosol sodium eye drops in Chinese patients with dry eye: a phase IV study.

Introduction: The efficacy and safety of 3% diquafosol sodium eye drops in Chinese patients with dry eye in the real-world setting remains unclear. Methods: 3099 patients with dry eye symptoms were screened according to Asia Dry Eye Society latest recommendation. Among them, 3000 patients were enrolled for a phase IV study. We followed up with multiple clinical characteristics including corneal fluorescein staining, tear break up time, Schirmer's tests, visual acuity, intraocular pressure, and others. The follow ups were performed at baseline, 2 weeks and 4 weeks after treatment. Results: Based on the results of corneal fluorescein staining and tear break up time, all age and gender subgroups exhibited obvious alleviation of the symptoms among the patients with dry eye, and the data in elderly group showed the most significant alleviation. All the adverse drug reactions (ADRs, 6.17%) were recorded, among which 6% local ocular ADRs were included. Meanwhile, mild ADRs (91.8%) accounted for the most. Most of the ADRs (89.75%) got a quick and full recovery, with an average time at 15.6 days. 1.37% of patients dropped out of the study due to ADRs. Discussion: The use of 3% diquafosol sodium eye drop is effective and safe in the treatment of dry eye, with a low incidence of ADRs showing mild symptoms. This trial was registered at Chinese Clinical Trial Registry ID: ChiCTR1900021999 (Registration Date: 19/03/2019).

Limbal epithelial stem/progenitor cells attract stromal niche cells by SDF-1/CXCR4 signaling to prevent differentiation.

Corneal epithelial stem cells (SCs) are an ideal model for investigating how adult lineage-committed epithelial SCs are regulated by an anatomically defined and accessible niche, that is, limbal palisades of Vogt, located between the cornea and the conjunctiva. We have used collagenase digestion to isolate the entire limbal epithelial SCs and subjacent mesenchymal cells, and we have demonstrated that their close association is crucial for promoting epithelial clonal growth, implying that the latter serves as niche cells (NCs). After their close association was disrupted by trypsin/EDTA, single SCs and NCs could reunite to generate sphere growth in three-dimensional Matrigel in the embryonic SC medium, and that such sphere growth initiated by SC-NC reunion was mediated by SDF-1 uniquely expressed by limbal epithelial progenitor cells and its receptor CXCR4, but not CXCR7, strongly expressed by limbal stromal NCs. Inhibition of CXCR4 by AMD3100 or a blocking antibody to CXCR4 but not CXCR7 disrupted their reunion and yielded separate spheres with a reduced size, while resultant epithelial spheres exhibited more corneal differentiation and a notable loss of holoclones. For the first time, these results provide strong evidence supporting that limbal SC function depends on close physical association with their native NCs via SDF-1/CXCR4 signaling. This novel in vitro model of sphere growth with NCs can be used for investigating how limbal SC self-renewal and fate decision might be regulated in the limbal niche.

The psychosocial benefits of secondary hydroxyapatite orbital implant insertion and prosthesis wearing for patients with anophthalmia.

PURPOSE: Anophthalmia is associated with a range of psychosocial difficulties and hydroxyapatite orbital implant insertion and prosthesis wearing is the predominant rehabilitation therapy for anophthalmia. However, few articles have compared preoperative and postoperative psychosocial outcomes using standardized questionnaires. This study aimed to investigate the psychosocial benefits of hydroxyapatite orbital implant insertion and prosthesis wearing in this patient population. METHODS: In all, 36 participants were tested preoperatively and 6-months postoperatively using standardized measures of anxiety and depression (Hospital Anxiety and Depression Scale), social anxiety and social avoidance (Derriford Appearance Scale-Short Form), and quality of life (World Health Organization Quality of Life Scale-Short Form). RESULTS: Before treatment, levels of depression were comparable with population norms; however, levels of general anxiety were slightly raised, levels of social anxiety, social avoidance, and quality of life were significantly poorer than population norms. Treatment resulted in significant improvement in psychosocial adjustment with improvements in all study variables for the participant group as a whole. CONCLUSION: Hydroxyapatite orbital implant insertion and prosthesis wearing offers significant improvements in psychological and physical functioning for patients with anophthalmia.

[Analysis of anatomy features for patients with narrow anterior chamber angle and primary iridociliary body cysts].

OBJECTIVE: To investigate the prevalence and anatomy features of iridociliary body cysts in patients with narrow anterior chamber angle. METHODS: Retrospective case series study. The prevalence and anatomy features of iridociliary body cysts in 223 patients (402 eyes) were analyzed retrospectively with ultrasound biomicroscopy (UBM). All of the patients were examined for susceptive narrow anterior chamber angle without complaint. The age of the patients, the site, diameter and number of cysts, the anterior chamber angle and the central anterior chamber depth were measured. RESULTS: Iridociliary body cysts were found in 19 patients (23 eyes) out of 223 patients (402 eyes), the prevalence is 5.7%. Fifteen patients were unilateral and four patients bilateral. Two cases originated from the ciliary process, eighteen cases from the iris root, and three from both the root and posterior surface of the iris. Twenty one cases were single cysts while two cases were multiple cysts. The diameter of the cysts ranged from 0.5 to 3.1 mm, averaged (0.71 ± 0.53) mm. The average age and the central anterior chamber depth of the eyes with iridociliary body cysts were (55.32 ± 10.74) years and (2.25 ± 0.39) mm, with no significant difference (t = 0.534, 0.783; P > 0.05) as compared to that of patients without cysts, which were (57.46 ± 10.52) years and (2.14 ± 0.34) mm. The anterior chamber angle in iridociliary body cysts group was 8.2° (21.0°, 0.0°), with no significant difference (Z = -0.062, P > 0.05) as compared to that of patients without cysts, which was 8.9° (21.4°, 0.0°). CONCLUSIONS: The prevalence rate of iridociliary body cysts in this study is 5.7%, central anterior chamber depth and anterior chamber angle in patients with cysts do not differ form patients without cysts.