Treatment of acute ocular chemical burns. Surv Ophthalmol. 2018;63:214-235. [PMID: 28935121 DOI: 10.1016/j.survophthal.2017.09.005]

The transcription factor BMAL1 inhibits endothelial cell apoptosis by targeting STAT6 to repress its expression

Corneal transparency is critical for optimal visual function, and corneal neovascularization represents the primary cause of visual impairment globally. Recent studies have identified the transcription factor BMAL1 as a significant regulator of angiogenesis. However, its specific role and underlying mechanisms in endothelial cell apoptosis remain inadequately understood. This study seeks to elucidate the role and underlying mechanisms of BMAL1 in endothelial cell apoptosis by employing genetic modification, alkali-burned mouse corneal neovascularization models, lentiviral transfection, proteomic analysis, and other complementary methodologies. Our results showed that BMAL1 expression is significantly elevated in corneal neovascularization induced by alkali burn and removal of Bmal1 in endothelial cells resulted in the suppression of corneal neovascularization in alkali burn mouse models. In vivo experiments have demonstrated that the knockout of Bmal1 in endothelial cells leads to an increase in endothelial cell apoptosis. Complementary in vitro studies revealed that overexpression of BMAL1 in endothelial cells inhibits apoptosis, while knockdown of BMAL1 promotes apoptosis. Proteomic analysis identified STAT6 as a downstream target of BMAL1 involved in the regulation of endothelial cell apoptosis. Further cell salvage experiments confirmed that BMAL1 modulates endothelial cell apoptosis through the regulation of STAT6 expression. Finally, the results of dual-luciferase reporter assay demonstrated that BMAL1 exerts transcriptional repressive effects on the promoter bound by STAT6. This study elucidates the novel role and mechanism of BMAL1 in the regulation of angiogenesis and endothelial cell apoptosis, thereby identifying a potential therapeutic target for the treatment of vascular diseases such as corneal neovascularization.

Silencing METTL3 and YTHDF2 increases HSP70 expression and promotes corneal epithelial healing

Delayed healing of corneal epithelial injury can cause irreversible scarring and severely affect vision. Outstanding progress has been made in recent years regarding corneal epithelial repair. However, studies investigating the role of N6-methyladenosine (m6A) in this process remain limited. The main objective of this study was to explore the role of m6A modification and its regulators in the healing of the corneal epithelium. In this study, we used the C57BL/6 mouse corneal alkali burn model as an in vivo model and human corneal epithelial cells (HCECs) as an in vitro subject. Small interfering RNA (siRNA) was used to downregulate the expression of YTHDF2, METTL3, and FTO in HCECs. We evaluated the effects of downregulating m6A modification regulators on the proliferation, migration, and apoptosis of HCECs under basal conditions and following IL-1β stimulation. The results suggest that m6A and its regulators are involved in the healing process of the corneal epithelium. Following corneal alkali burns, m6A levels were elevated, while the expression of METTL3, FTO, and YTHDF2 was reduced. In HCECs stimulated with IL-1β, m6A levels were significantly increased, and the expression of FTO and YTHDF2 was decreased. Silencing METTL3 and YTHDF2 enhanced the proliferation and migration of HCECs by increasing HSP70 expression, thereby facilitating corneal epithelial healing. In contrast, silencing FTO may impede corneal epithelial healing by promoting apoptosis in HCECs and inhibiting their proliferation and migration. This study offers a novel perspective on the treatment of delayed corneal epithelial healing.

The revolutionary role of placental derivatives in biomedical research

The human placenta is a transient yet crucial organ that plays a key role in sustaining the relationship between the maternal and fetal organisms. Despite its historical classification as "biowaste," placental tissues have garnered increasing attention since the early 1900s for their significant medical potential, particularly in wound repair and surgical application. As ethical considerations regarding human placental derivatives have largely been assuaged in many countries, they have gained significant attention due to their versatile applications in various biomedical fields, such as biomedical engineering, regenerative medicine, and pharmacology. Moreover, there is a substantial trend toward various animal product substitutions in laboratory research with human placental derivatives, reflecting a broader commitment to advancing ethical and sustainable research methodologies. This review provides a comprehensive examination of the current applications of human placental derivatives, explores the mechanisms behind their therapeutic effects, and outlines the future potential and directions of this rapidly advancing field.

TLR4 signal inhibition alleviates alkali-burn induced corneal neovascularization

Toll-like receptor 4 (TLR4), recognized as a fundamental mediator of inflammatory signaling, plays a crucial role in orchestrating the inflammatory response. Previous studies suggested that TLR4 knockout (KO) notably reduced corneal vascular areas induced by silver nitrate burn based on the morphological observation. The current study seeks to elucidate the influence of TLR4 signaling on corneal neovascularization (CNV) and to examine the underlying mechanisms. The model of alkali burn (AB)-induced CNV was built using TLR4 KO and wildtype (WT) mice. CNV was detected using a slit lamp. Corneal thickness was evaluated using H&E staining. The expression levels of VEGF-A, MyD88, and NF-κB were evaluated employing Western blot analysis, immunohistochemistry, and Real-time PCR techniques. The inflammation factors, IL-1β, TNF-α, and IL-6, were quantified using Real-time PCR. In addition, Resatorvid (Tak242), a specific inhibitor of TLR4, was used to treat AB cornea of WT mice. AB enhanced TLR4 signaling components, including MyD88 and NF-κB. TLR4 inhibition alleviated AB-induced corneal neovascularization and corneal thickness. The TLR4 signal, inflammatory factors and VEGF-A were also down-regulated. Our data indicated that TLR4 participated in the pathology of AB-induced CNV. TLR4 was over-expressed in the cornea of AB mice. TLR4 inhibition alleviated AB-induced CNV, and suppressed MyD88, NF-κB, VEGF-A, and inflammation factors. These findings may provide new insights for the clinical treatment of AB-induced CNV.

RIPK3-Mediated Necroptosis Drives Macrophage Infiltration and Corneal Neovascularization After Alkali Burn

Purpose

To reveal the role of receptor-interacting protein kinase 3 (RIPK3) in regulating macrophage inflammation and corneal neovascularization (CoNV) induced by alkali burn.

Methods

A corneal alkali burn (AB) model was established in C57BL/6J (wild-type) and RIPK3fl/flCx3cr1+/cre (RIPK3-/-, RIPK3 knockout [KO]) mice using sodium hydroxide. Anterior segment optical coherence tomography and hematoxylin and eosin staining were used to evaluate the impact of RIPK3 on corneal edema and morphology. CoNV was detected by slit-lamp microscopy and whole-mount immunofluorescence staining of cornea. Corneal macrophage and necroptotic cell death was analyzed through immunofluorescence staining and propidium iodide (PI) staining. Activation of the necroptosis pathway was examined after corneal AB by western blot.

Results

Necroptosis-related proteins RIPK1, RIPK3, and mixed lineage kinase domain-like (MLKL) were upregulated and activated following corneal AB. Among these, RIPK3 demonstrated the most pronounced increase. Notably, the elevated level of RIPK3 was prominently colocalized with the infiltrating F4/80+ macrophages. RIPK3 KO significantly alleviated corneal edema and morphology defects. Additionally, as the corneal morphological defects progressed, macrophages became activated, and CoNV and lymphangiogenesis (LyG) were enhanced. RIPK3 KO markedly reduced AB-induced macrophage accumulation, as well as CoNV and LyG. RIPK3 KO mice also showed a meaningful decrease in PI+ necroptotic cells. Mechanistically, AB-induced necroptosis stimulated the expression of MLKL and fibroblast growth factor 2 (FGF2), whereas RIPK3 deficiency decreased their expression.

Conclusions

This study revealed that RIPK3-mediated necroptosis drives macrophage inflammation and CoNV. Targeting RIPK3 could effectively suppress these responses by inhibiting the MLKL/FGF2 pathway, making it a promising therapeutic strategy for corneal AB.

Bovine amniotic membrane with antioxidant and anti-inflammatory properties for the repair of alkali-burned corneas

Corneal alkali burns are a common ocular emergency that can lead to blindness, marked by inflammation and delayed epithelial healing due to elevated oxidative stress in the intraocular environment. Mitigating the levels of reactive oxygen species (ROS) and the inflammatory response is essential for developing corneal repair materials. Amniotic membrane (AM) is frequently employed for ocular surface repair but faces limitations such as limited availability and rapid degradation. This study developed a crosslinked decellularized bovine amniotic membrane (CAM) with high transparency, enhanced mechanical strength, and enzyme resistance. By introducing Manganese-based carbon dots (Mn CDs), the composite (CDs@CAM) retained the physical properties of CAM meanwhile brought in the multi-enzyme activities of Mn CDs. Extensive characterizations demonstrated CDs@CAM high CAT-like activity, SOD-like activity and scavenging ability of hydroxyl radical and nitrogen radical. Furthermore, cellular and animal experiments demonstrated that the CDs@CAM possessed good biocompatibility, strong antioxidant capabilities, and anti-inflammatory effects, and thus significantly promoted corneal epithelial regeneration, inhibited neovascularization, and prevented scarring in alkali burn repair. This study offers a feasible strategy for artificial corneas and corneal disease treatment. STATEMENT OF SIGNIFICANCE: In this study, we developed a crosslinked decellularized bovine amniotic membrane (CAM) integrated with manganese-based carbon dots (Mn CDs), creating a composite material (CDs@CAM) that addressed the issue of high oxidative stress and severe inflammation in the eye caused by corneal alkali burns. Different from the conventional amniotic membrane products, CDs@CAM retains advantageous physical properties and biocompatibility of CAM while offering potent antioxidant and anti-inflammatory capabilities. We confirmed its good biocompatibility, as well as reductions in intracellular ROS levels and inflammatory responses. Importantly, in an alkali-burned cornea model, we revealed its outstanding performance in promoting corneal epithelial repair, inhibiting neovascularization, and thus preventing scarring, restoring corneal thickness and clarity to normal levels.

DNA methylation modification: Dawn of research on cornea-related diseases

DNA methylation is a significant form of epigenetic modification that plays a crucial role in the occurrence and progression of diseases by regulating gene expression. Recent advancements in our understanding of DNA methylation have demonstrated its involvement in corneal damage repair and various corneal diseases. This article reviews the mechanisms and effects of DNA methylation modifications in corneal injury repair, keratoconus, corneal dystrophy, keratitis, and other related conditions. The aim is to enhance our understanding of the vital role of DNA methylation in the pathogenesis of corneal injuries and the development of cornea-related diseases. The phenomenon of DNA methylation in these conditions may offer new ideas and insights for therapeutic approaches.

Cannabidiol-loaded hydrogel contact lenses for on-demand pH regulation and enhanced corneal alkali burn repair

Corneal alkali burn (CAB) poses a significant therapeutic challenge due to alkali infiltration, bacterial infection, inflammation, and angiogenesis, which collectively hinder recovery. The pH microenvironment after CAB is critical for the healing process, but there are few functional biomaterials for this purpose at present. Herein, we develop a multifunctional hydrogel contact lens (CL) with on-demand release of citric acid (CA) and cannabinoid (CBD), triggered by alkaline conditions, to regulate the microenvironment pH and enhance CAB repair. The CA-functionalized polyvinyl alcohol (PC) and quaternary ammonium chitosan (QCS) are used as hydrogel frameworks, with CBD incorporated as a functional component. The (CBD/QCS/PC, CBD/QPC) hydrogel CL is fabricated using a repeated freeze-thaw process to achieve an interpenetrating network structure. The findings suggest that the 1CBD/QPC hydrogel CL exhibit superior mechanical properties and biocompatibility (hemolysis rate < 0.6 %, cell viability>90 %). These properties enhance wearing comfort and reducing secondary inflammation. Notably, this hydrogel can release CA (52.23 ± 2.78 %) and CBD (59.24 ± 5.15 %) within 24 h under alkaline conditions to neutralize pH, significantly down-regulate the expression level of inflammatory factors and remove hydroxyl radicals. This mechanism fundamentally addressing the secondary damage of residual lye following CAB. Moreover, the hydrogel CL exhibit potent inhibitory effects on the colonization and growth of both E. coli and S. aureus by destroying bacterial membranes, with an inhibition rate > 90 %. In vivo results show that hydrogel CL promote the repair of CAB through anti-inflammatory effects and angiogenesis inhibition. In conclusion, these results demonstrate the potential of this hydrogel CL for treating corneal alkaline burns, providing new insights into treatment of CAB.

Development and optimization of an ex vivo model of corneal epithelium damage with 1-heptanol: Investigating the influence of donor clinical parameters and MSC-sEV treatment on healing capacity

PURPOSE

To develop and characterize a reproducible human corneal epithelial wound-healing model using 1-heptanol, and to investigate the healing potential of Bone Marrow-derived Mesenchymal Stromal Cell small Extracellular Vesicles (MSC-sEV) and the influence of donor characteristics on epithelial healing.

METHODS

Eighty-eight (n = 88) human corneoscleral tissues unsuitable for transplantation were employed. Corneal epithelial damage was induced with 1-heptanol and monitored every 24 h up to 96 h using fluorescein and trypan blue staining. Histological assessment was performed on untreated and damaged tissues. Damaged areas were measured with FIJI software, and healing rates were calculated. MSC-sEV were isolated with size exclusion chromatography and characterized for their size, morphology and biomarkers. Their impact on healing was assessed in both in vitro scratch assays on cultured human corneal epithelial cells and on ex vivo 1-heptanol-damaged corneas.

RESULTS

Histological analysis revealed detached corneal epithelium in the central area, while other layers remained unaffected. Healing rate peaked at 48 h post-damage. Trypan blue and Fluorescein staining correlated and the former highlighted a higher initial healing rate than the latter. Diabetic and heart-beating brain-deceased donors showed impaired healing rates. MSC-sEV (79.8 nm, spherical bilayer, positive for TSG101, CD9, CD63, and CD81) significantly improved epithelial wound healing in both in vitro and ex vivo models.

CONCLUSION

1-heptanol effectively induces reproducible corneal epithelial damage, and the ex vivo organ-cultured human cornea heals the epithelium within 96 h. Diabetes and donation from heart-beating brain-deceased donors reduce healing capacity. MSC-sEV boost epithelial repair in damaged corneas.

Management of corneal injuries in spaceflight and recommendations for planetary missions

In February 1968, NASA purchased 400 antigravity ballpoint pens from the Fisher Pen Company for the Apollo Program to prevent potential harm to astronauts and equipment. Mechanical pencils previously used in microgravity posed risks like eye injuries from floating fragments penetrating the cornea. The cornea is vulnerable to abrasions, perforations, and chemical burns in such environments, affecting crewmembers aboard the International Space Station (ISS). While they undergo extensive training for emergency situations, there are inherent complexities when faced with eye injuries. In this challenging context, adapting available medications and leveraging emergency medical training is critical for addressing ocular injuries in a high-stakes environment. This paper explores ISS medications and management strategies for corneal injuries, highlighting the need to include effective medications and countermeasures in future ISS medical kits.

Corneal first aid lens: Collagen-based hydrogels loading aFGF as contact lens for treating corneal injuries

Severe corneal injuries can cause visual impairment even blindness. Surgically stitching or implanting biomaterials have been developed, but their implementation requires professional surgeons, failing to address the immediate need of medical treatment. The pressing challenge lies in developing multifunctional biomaterials that enable self-management of corneal injuries. This study introduces collagen-based hydrogels that can be used as contact lenses, incorporating macromolecular collagen into common polymer materials via a dual-step orthogonal cross-linking process. This method ensures superior optical and mechanical performance while preserving the bioactivity and structural stability of the incorporated materials. Specialized contact lens facilitates the controlled release of labile protein therapeutics such as acidic fibroblast growth factor (aFGF), eliminating the need for stabilizers like heparin. This capability allows the lens to deliver a wide range of labile proteins, thus expanding its therapeutic use across various ophthalmic and potentially other medical conditions. The lens's anti-inflammatory and anti-fibrotic properties effectively treat corneal alkali burn. Termed 'corneal first-aids lens', it can provide postoperative clinical care and serve as a viable and safe therapeutic alternative for patients with limited medical access.

Long-lasting comfort ocular surface drug delivery by in situ formation of an adhesive lubricative Janus nanocoating

Topical drug delivery on ocular surface always suffers from frequent administration and low bioavailability due to short drug residence. Despite advances of different adhesive ophthalmic drugs in extending release, cornea and eyelid nonselective adhesion inevitably causes ocular discomfort and even damage. Here, we describe in situ formation of an adhesive lubricative Janus nanocoating (ALJN) to enable long-lasting comfort drug delivery. By iron complexation, an asymmetric ALJN is formed on ocular surface via facile sequential instillation. The adhesive polyphenol inner layer binding with ocular surface enables drug loading and sustained release, while the lubricative zwitterionic polymer outer layer prevents eyelid adhesion to ensure comfort. Following instillation, ALJN retains on ocular surface over 24 hours and reduces blinking frequency to normal level. Moreover, ALJN demonstrates remarkable therapeutic potential in mouse and rabbit models of corneal contusion and alkali burn. This work proposes a comfortable long-lasting topical delivery platform for treating various ocular diseases.

Isolated Mitochondrial Transplantation as a Novel Treatment for Corneal Chemical Burns

Purpose

This study aimed to investigate the therapeutic potential of isolated mitochondrial transplantation for the restoration of corneal surface injury in mice after corneal chemical burn.

Methods

Mitochondria were isolated from mesenchymal stem cells via ultracentrifugation, followed by an assessment of their purity and viability. The internalization of mitochondria by human corneal epithelial cells was tracked using a live fluorescence imaging system. Apoptosis-related markers and mitochondrial function were measured by Western blotting and flow cytometry, respectively. Mitochondrial morphology was examined using confocal laser scanning microscopy. The therapeutic effects of subconjunctival administration of isolated mitochondria in vivo were evaluated by fluorescein sodium staining and histopathological examination of the corneas.

Results

Our study demonstrates that corneal epithelial cells possess the capacity to internalize isolated exogenous mitochondria in vitro. Under oxidative stress conditions, recipient cells exhibited an enhanced uptake of exogenous mitochondria. We observed a decrease in apoptosis and a reduction in oxidative stress levels within the recipient cells, as well as a partial restoration of mitochondrial function. Notably, after a single subconjunctival injection, corneal epithelial cells were able to use isolated mitochondria to enhance the repair process in a mouse model of corneal acid burn.

Conclusions

Subconjunctival injection of isolated mitochondria promoted the repair of acute corneal burns in mice. The results of our investigation using injection of isolated mitochondria as a treatment modality for corneal chemical burn offers a novel approach to the treatment of ocular disorders associated with mitochondrial dysfunction.

Topical application of amniotic membrane extract at a clinically correlated dose is effective in limiting complications in an experimental ocular alkaline burn model

The purpose of this study is to investigate the clinical and histopathological effectiveness of topical amniotic membrane extract (AME) applied at a clinically relevant dose in an experimental corneal alkaline burn model and to compare the results with amniotic membrane transplantation (AMT) as one of the most frequently used biologically based treatment options. To create an alkaline burn model, NaOH-impregnated filter paper was applied to all rabbits for 30 s. Rabbits were divided into 3 groups: Group 1 (n = 6): AME eye drop; Group 2 (n = 6): AMT; Group 3 (n = 4): control group. AME eye drops were applied as 1 drop 4 times a day for 28 days. Clinical findings including corneal opacity, corneal vascularization, limbal stem cell deficiency (LSCD) was evaluated and graded in accordance with the updated literature. On day 28, corneas were histopathologically examined under the light microscope. Stromal inflammation, stromal fibrosis, intraepithelial edema, and corneal vascularization were scored in each group. When the groups were compared clinically, corneal opacity was significantly (p = 0.009) lower in the AME group. While lower LSCD grades were observed in the AME group, this difference was not significant (p > 0.05). Histopathologically; in the AME group, stromal inflammatory cell inflammation, corneal vascularization, intraepithelial edema, stromal fibrosis, and metaplastic epithelial layer thickness were significantly (p = 0.004; p = 0.022; p = 0.008; p = 0.002; p = 0.002, respectively) lower than the other groups.In this study, it was shown that AME eye drops were clinically and histopathologically more successful in providing corneal healing than the AMT and control groups in the ocular alkaline burn model. These findings are valuable as they show that AME eye drops may be an easy-to-apply biologically based treatment alternative to AMT in chemical burns.

Public Awareness of Ocular Chemical Injuries: A Cross-Sectional Study in Lithuania

Background: Ophthalmic emergencies are acute conditions that progress rapidly, posing a significant threat to a patient's vision and requiring urgent intervention to prevent permanent visual impairment. This study aimed to assess the general awareness of ocular chemical burns and the adequacy of the immediate response measures while also seeking to improve the understanding of these injuries and contribute to promoting a healthier society. Methods: A comprehensive literature review was performed, and the most frequently reported questions were incorporated into the original survey. An anonymous questionnaire, available both online and in print, was developed to conduct a cross-sectional study to assess the general knowledge of the causes, symptoms, and appropriate first aid measures to be applied in cases of chemical ocular trauma. Results: Between April and May 2024, 175 individuals completed the questionnaire and were included in the study. More than half (54%) of the tested population demonstrated a poor level of knowledge about chemical ocular injuries, and only 30.9% of the respondents correctly indicated the need for imminent treatment. Twenty percent of the respondents could not identify whether alkalis or acids are more hazardous. Additionally, 5.7% of the respondents falsely considered consultation with an emergency department a priority before thorough irrigation. Most of the respondents (60.6%) incorrectly indicated that the appropriate first aid measures and treatment depend on the substance involved, and 68.1% of the respondents stated that treatment in the emergency department should be delayed, allowing for anamnesis collection and thorough examination. Conclusions: Ocular chemical injuries can substantially impact an individual's quality of life. The present study found that the public knowledge concerning ocular chemical trauma, and the necessary immediate treatment is insufficient. Public education is vital, as delaying prompt and thorough irrigation at the chemical injury site may result in irreversible complications.

Human embryonic stem cell-derived immunity-and-matrix-regulatory cells on collagen scaffold effectively treat rat corneal alkali burn

Corneal alkali burns (CAB) are a severe form of ocular injury that often leads to significant vision loss, with limited effective treatment options available beyond corneal transplantation. Immunity and matrix-regulatory cells (IMRCs) have emerged as a promising alternative due to their ability to modulate immune responses and support tissue repair. This study investigates the efficacy of IMRCs on collagen scaffolds (IMRCs-col) for treating CAB in a rat model. We developed a novel treatment combining IMRCs with a collagen scaffold to align with the ocular surface structure. In vitro analyses showed that IMRCs-col significantly upregulated the expression of immune regulatory molecules, including IL-1RA and SCF. Additionally, IMRCs-col effectively inhibited the production of pro-inflammatory cytokines (IL-8 and Gro-a/CXCL1) while promoting pro-regenerative cytokines (bFGF, HGF, and PDGF). In an animal model of CAB, IMRCs-col transplantation demonstrated substantial efficacy in restoring corneal opacity and reducing neovascularization. Histological examination revealed reduced inflammation and improved corneal tissue regeneration compared to untreated CAB. Enhanced activation of pathways associated with anti-inflammatory responses and tissue repair was observed at days 3, 7, and 21 post-treatment.

Beyond transplants: current and future therapeutic potential of amniotic membrane extract (AME) in ophthalmology

There is no established consensus or standardized method for the preparation of amniotic membrane extract (AME). Consequently, various preparation, preservation, and sterilization techniques have been employed. To obtain AME rich in bioactive components with high therapeutic efficacy, each step of the preparation process is of critical importance. The appropriate procurement of the amniotic membrane minimizes the risk of infection transmission and reduces inter- and intra-donor variability. For the subsequent extraction process, different approaches are utilized due to factors such as laboratory infrastructure variability and the lack of a standardized method. Although lyophilization has recently emerged as a prominent method for the long-term preservation of AME, further investigation is required to assess its impact on the biochemical composition and clinical efficacy of the membrane. In ophthalmology, in vitro, in vivo, and clinical studies indicate that AME supports corneal epithelial regeneration, suppresses inflammation, and is a well-tolerated therapeutic agent. Consequently, further studies are still needed to enhance the effective release of therapeutic components from the amniotic membrane, improve the quality and consistency of AME, and preserve its content over an extended period. Thus, the clinical application of AME-derived products in the form of eye drops will become more widespread in the future.

Procurement, Processing, and Storage of Human Amniotic Membranes for Implantation Purposes in Non-Healing Pressure Ulcers

The human amniotic membrane (hAM) has been used as an implant to enhance the regenerative process and control inflammation in different diseases, given their structure, biocompatibility, presence of stem cells and multiple growth factors. The objective of this study was to generate a standardized protocol for obtaining, processing, and storing hAMs that guarantee the conservation of their structural and cellular characteristics as well as their mechanical properties, ensuring their ease of handling, sterility, and quality that allows their implementation for therapeutic purposes in the field of regenerative medicine. The hAMs were obtained from mothers with healthy, full-term, controlled pregnancies and by cesarean section. The hAMs were processed under sterile conditions, manually separated from the placenta and, subsequently, they were frozen in a solution of culture medium plus 50% v/v glycerol. The protocol allows obtaining sterile hAMs composed of both epithelium and stroma with adequate preservation of the amniotic cells. The glycerol's impact on the mechanical properties may enhance the membrane's adaptability and conformability to diverse wound surfaces, potentially improving the healing process. It is necessary to repeat microbiological, cell viability and mechanical studies at 6 and 12 months to ensure that long-term frozen conditions do not affect the quality of the hAMs.

Progress in Nanotechnology for Treating Ocular Surface Chemical Injuries: Reflecting on Advances in Ophthalmology

Ocular surface chemical injuries often result in permanent visual impairment and necessitate complex, long-term treatments. Immediate and extensive irrigation serves as the first-line intervention, followed by various therapeutic protocols applied throughout different stages of the condition. To optimize outcomes, conventional regimens increasingly incorporate biological agents and surgical techniques. In recent years, nanotechnology has made significant strides, revolutionizing the management of ocular surface chemical injuries by enabling sustained drug release, enhancing treatment efficacy, and minimizing side effects. This review provides a comprehensive analysis of the etiology, epidemiology, classification, and conventional therapies for ocular chemical burns, with a special focus on nanotechnology-based drug delivery systems in managing ocular surface chemical injuries. Twelve categories of nanocarrier platforms are examined, including liposomes, nanoemulsions, nanomicelles, nanowafers, nanostructured lipid carriers, nanoparticles, hydrogels, dendrimers, nanocomplexes, nanofibers, nanozymes, and nanocomposite materials, highlighting their advantages in targeted delivery, biocompatibility, and improved healing efficacy. Additionally, current challenges and limitations in the field are discussed and the future potential of nanotechnology in treating ocular diseases is explored. This review presents the most extensive examination of this topic to date, aiming to link recent advancements with broader therapeutic strategies.

Drug delivery strategies to improve the treatment of corneal disorders

Anterior eye disorders including dry eye syndrome, keratitis, chemical burns, and trauma have varying prevalence rates in the world. Classical dosage forms based-topical ophthalmic drugs are popular treatments for managing corneal diseases. However, current dosage forms of ocular drugs can be associated with major challenges such as the short retention time in the presence of ocular barriers. Developing alternative therapeutic methods is required to overcome drug bioavailability from ocular barriers. Nanocarriers are major platforms and promising candidates for the administration of ophthalmic drugs in an adjustable manner. This paper briefly introduces the advantages, disadvantages, and characteristics of delivery systems for the treatment of corneal diseases. Additionally, advanced technologies such as 3D printing are being considered to fabricate ocular drug carriers and determine drug dosages for personalized treatment. This comprehensive review is gathered through multiple databases such as Google Scholar, PubMed, and Web of Science. It explores information around "ocular drug delivery systems'', "nano-based drug delivery systems'', "engineered nanocarriers'', and "advanced technologies to fabricate personalized drug delivery systems''.

Enhanced Corneal Repair with Hyaluronic Acid/Proanthocyanidins Nanoparticles

This study investigates the therapeutic potential of hyaluronic acid/proanthocyanidin (HA/PAC) nanoparticles in treating alkali-induced corneal burns. Alkali burns are common ocular emergencies that can lead to severe vision impairment if not promptly and properly treated. The low water solubility of proanthocyanidins (PACs), which are potent antioxidant and anti-inflammatory agents, limits their bioavailability and therapeutic efficacy. To overcome this, hyaluronic acid (HA) was utilized as a carrier to form HA/PAC nanoparticles, enhancing PAC's solubility and bioavailability. The HA/PAC nanoparticles were characterized for morphology, granulometric distribution, hemolysis, and cytotoxicity, demonstrating high blood compatibility and noncytotoxicity. The in vitro antioxidant and anti-inflammatory capacities of HA/PAC were evaluated, showing enhanced activity compared to PAC alone. In vivo studies on C57 mice confirmed the accelerated healing of corneal injuries and reduced corneal opacity with HA/PAC treatment. Histopathological analysis and cytokine quantification further supported the anti-inflammatory and proregenerative effects of HA/PAC, suggesting its potential as an effective treatment for corneal alkali burns.

Next-generation methods for precise pH detection in ocular chemical burns: a review of recent analytical advancements

Ocular burns due to accidental chemical spillage pose an immediate threat, representing over 20% of emergency ocular traumas. Early detection of the ocular pH is imperative in managing ocular chemical burns. Alkaline chemical burns are more detrimental than acidic chemical burns. Current practices utilize litmus, nitrazine strips, bromothymol blue, fluorescent dyes, and micro-combination glass probes to detect ocular pH. However, these methods have inherent drawbacks, leading to inaccurate pH measurements, less sensitivity, photodegradation, limited pH range, and longer response time. Hence, there is a tremendous necessity for developing relatively simple, accurate, precise ocular pH detection methods. The current review aims to provide comprehensive coverage of the conventional practices of ocular pH measurement during accidental chemical burns, highlighting their strengths and weaknesses. Besides, it delves into cutting-edge technologies, including pH-sensing contact lenses, microfluidic contact lenses, fluorescent scleral contact lenses, fiber optic pH technology, and pH-sensitive thin films. The study meticulously examines the reported work since 2000. The collected data have also helped propose future directions, and the research gap needs to be filled to provide a more rapid, sensitive, and accurate measurement of ocular pH in eye clinics. For the first time, this review consolidates current techniques and recent advancements in ocular pH detection, offering a strategic overview to propel ophthalmic-related research forward and enhance ocular burn management during a chemical spillage.

Recombinant Thrombomodulin Domain 1 Modulates Macrophage Polarization and Enhances Healing in Corneal Alkali Burns

Purpose

Corneal alkali burns are severe ocular injuries characterized by intense inflammation, tissue damage, and vision impairment, with current treatments often insufficient in restoring corneal function and clarity. This study aimed to evaluate the therapeutic effects of recombinant thrombomodulin domain 1 (rTMD1) in the treatment of corneal alkali burns, focusing on its impact on inflammation, tissue repair, fibrosis, and neovascularization.

Methods

A murine model of corneal alkali burn was utilized to investigate the therapeutic potential of rTMD1. The effects of rTMD1 on macrophage polarization, inflammatory response, tissue repair, fibrosis, and neovascularization were assessed through histological analysis, immunohistochemistry, and molecular studies targeting key signaling pathways such as ERK/HIF-1α and vascular endothelial growth factor (VEGF) expression.

Results

Administration of rTMD1 significantly modulated macrophage polarization, promoting a transition from the pro-inflammatory M1 phenotype to the reparative M2 phenotype via inhibition of the ERK/HIF-1α pathway. This shift resulted in reduced inflammation, enhanced tissue repair, and controlled fibrosis. Furthermore, rTMD1 inhibited neovascularization by downregulating VEGF expression, aiding in the preservation of corneal clarity.

Conclusions

rTMD1 demonstrates substantial therapeutic potential in treating corneal alkali burns by reducing inflammation, promoting tissue repair, controlling fibrosis, and inhibiting neovascularization. These findings support the further development of rTMD1 as a promising treatment for corneal burns and possibly other inflammatory ocular conditions.

Histone methylation regulates neutrophil extracellular traps to attenuate corneal neovascularization

Corneal neovascularization (CNV) severely affects corneal transparency and disrupts the homeostasis of the ocular environment. However, the underlying mechanism of CNV remains unclear. In this study, we investigated the role of neutrophil extracellular traps (NETs) played in CNV and how histone methylation regulates the characterization of NETs. We used an alkali-burn-induced mice CNV model and human primary neutrophils to observe the involvement of NETs during CNV and change in its histone methylation. Transcriptomic analysis was performed to demonstrate the involvement of NETs during corneal alkali burn. We used the histone demethylase inhibitor JIB-04 to regulate the histone methylation of NETs and explored the related effects on CNV formation. NETs were obviously involved in corneal alkali burn and could be stimulated by NaOH in vitro. Isolated NETs aggravated CNV and promoted migration, proliferation and tube formation of vascular endothelial cells, while disruption of NETs significantly ameliorated angiogenesis and inflammation in vivo and in vitro. Mechanistically, histone methylation of NETs was inhibited by alkali burn and restored by JIB-04. Furthermore, we discovered that JIB-04 reduced CNV and NETs formation by regulating the NF-κB/ERK/ROS pathway. In conclusion, this study claims a novel role for histone methylation in regulating NETs formation and thereby affecting angiogenesis, which indicates a novel therapeutic target for CNV and other neovascularization-related diseases.

Exploring the therapeutic potential: sinomenine and melatonin in alkali-induced corneal burns

PURPOSE

This study aimed to investigate the effects of sinomenine and melatonin on corneal alkali burns.

METHODS

Twenty-seven female Wistar albino rats, aged 3-6 months and weighing 200-300 g, were used in this study. After the induction of general anesthesia, 2 mol/L sodium hydroxide (NaOH) solution was used to create corneal alkali burns in all experimental animals. The rats were divided into three groups: Group C, control group with no additional treatment; Group M, topical melatonin drop group; and Group S, topical sinomenine group. The rats were sacrificed under general anesthesia on the 7th day. Various parameters, including corneal inflammation, neovascularization, epithelialization, epithelial proliferating cell nuclear antigen (PCNA), epithelial inducible nitric oxide synthase (INOS), stromal INOS, and thickness, were evaluated.

RESULTS

The experiment was completed with 27 rats distributed into three groups of nine rats each. Significant differences were observed between the groups in terms of stromal thickness, inflammation, epithelial iNOS, stromal iNOS, and epithelialization (p = 0.008, p = 0.005, p = 0.020, p = 0.037, and p = 0.000, respectively). The best stromal thickness was observed in Group M. Vascularization, inflammation, epithelial INOS, stromal iNOS, and epithelialization were most effectively reduced in Group S, followed by Group M. Group S outperformed Group C significantly in all these aspects (p = 0.049, p = 0.004, p = 0.015, p = 0.036, p = 0.000, respectively). There was no significant difference between the groups in terms of the epithelial PCNA levels (p = 0.259).

CONCLUSIONS

The results suggest that topical sinomenine and melatonin have anti-inflammatory, anti-angiogenic, and reepithelialization effects when applied after alkali burns in rat corneas.

Case report: Two-step lamellar keratoplasty for alkali burns

Purpose

To report a case of a patient with ocular surface alkali burn who developed corneal perforation before entering a stable phase. This patient was treated with a custom-designed lamellar graft using a Two-Step lamellar keratoplasty (LK) after 3 months alkali burn.

Methods

This study was a case report.

Results

A 43-year-old male patient who presented with redness, pain, and decreased vision in his left eye following lime exposure. Initial treatment involved amniotic membrane transplantation and anterior chamber irrigation. However, the patient subsequently developed corneal infiltration and progressive thinning. The patient refused the corneal transplantation and ultimately underwent tarsorrhaphy. Twenty days postoperatively, the patient experienced sudden ocular pain and central corneal perforation. Considering the potential complications of conventional corneal transplantation, including stem cell deficiency, graft dissolution, and rejection, a personalized Two-Step LK was devised. Following this procedure, the patient's vision gradually improved to 20/133 (without correction), with a good corneal condition but mild epithelial defects and edema. At the 8-month follow-up, subepithelial corneal haze was observed, but uncorrected visual acuity remained stable at 20/133 and best corrected visual acuity was up to 20/66.

Conclusion

For patients with ocular surface alkali burns who experience persistent disease progression despite early and mid-stage aggressive interventions, this study is the first to report on the use of a Two-Step LK. This approach takes into account both the "soil" factors that may lead to graft dissolution and the "seed" factors related to recipient stem cell deficiency. The results in preventing graft dissolution and maintaining postoperative corneal function are encouraging.

The effect of platelet-rich plasma and sodium alginate hydrogel on corneal wound healing after corneal alkali burns in rats with computer-assisted anterior segment optical coherence tomography image analysis

Our objective was to determine the effect of a semi-synthetic sodium alginate hydrogel and its combination with platelet-rich plasma (PRP) on histopathological, biochemical, clinical, and anterior segment optical coherence tomography (AS-OCT) data. Alkali chemical burn of the cornea was induced. Injured rats were randomly divided into five equal groups and topically treated with phosphate-buffered saline (sham), platelet-rich plasma (PRP), 0.5% sodium citrate, a semi-synthetic sodium alginate hydrogel, or a combination of PRP and hydrogel (combined group) three times daily. The degree of corneal opacity (CO), corneal epithelial staining (CES), percentage of corneal epithelial defects (CEDP), degree of ciliary hyperemia (CH), neovascularization size (NVS), and extent of neovascularization (NVE) were evaluated. AS-OCT was performed at nine days, and then rats were sacrificed. Histological examination and enzyme-linked immunosorbent assays were performed to detect the concentrations of IL-1β and MMP-9 in the cornea. There were no significant differences between the groups regarding CEDP, CO, CES, CH, NVS, or NVE on the first day after corneal alkali burn injury (p > 0,05). At the last examination, CO was significantly lower in the PRP group than in the sham group (p = 0,044), while the CO concentrations were similar in terms of NVS (p > 0,05). Similarly, in terms of tissue MMP-9 levels, there were no significant differences between groups (p > 0,05). However, there was a significant difference in tissue IL-1β levels between the groups (p < 0,001). In the PRP and combined groups, the level of IL-1β was significantly lower than that in the sham group (p = 0,043 and p = 0,036, respectively). There was a significant difference in epithelial necrosis between the PRP, and it was the lowest in the combined group (p = 0,003). Epithelial thickness was highest in the combined group (p = 0,002). CEDP was significantly different at the last visit between the groups (p = 0.042). The fastest epithelial closing rate was observed for the combined group (p = 0,026). There was a significant negative correlation between tissue MMP-9 levels and corneal solidity and between tissue MMP-9 levels and the corneal area according to the AS-OCT measurements (p = 0,012 and p = 0,027, respectively). When used alone, topical hydrogel application did not significantly enhance the healing of corneal wounds. However, when combined with PRP, it leads to an increased rate of epithelial closure and neovascularization. This combination did not exacerbate inflammation or corneal opacity compared to PRP alone. The anticoagulant citrate solution in the PRP tube did not prove effective. The synergistic use of PRP and hydrogel could enhance epithelial thickness and reduce epithelial necrosis. The use of new parameters for corneal wound healing assessment was facilitated through AS-OCT image processing.

Cannabidiol alleviates suture-induced corneal pathological angiogenesis and inflammation by inducing myeloid-derived suppressor cells

BACKGROUND

Currently, no perfect treatment for neovascularization and lymphangiogenesis exist, and each treatment method has its complications and side effects. This study aimed to investigate the anti-angiogenic and anti-inflammatory effects of cannabidiol and its mechanism of action.

METHOD

An in vivo corneal neovascularization (CNV) model was established using the suture method to investigate the inhibitory effects of CBD on suture-induced corneal inflammation, pathological blood vessel formation, and lymphangiogenesis. Additionally, the impact of CBD on immune cells was studied. In vitro methodologies, including cell sorting and co-culture, were employed to elucidate its mechanism of action.

RESULTS

Compared with the CNV group, CBD can inhibit CNV, lymphangiogenesis, and inflammation induced via the suture method. In addition, CBD specifically induced CD45+CD11b+Gr-1+ cell upregulation, which significantly inhibited the proliferation of CD4+ T lymphocytes in vitro and exhibited a CD31+ phenotype, proving that they were myeloid-derived suppressor cells (MDSCs). We administered anti-Gr-1 to mice to eliminate MDSCs in vivo and found that anti-Gr-1 partially reversed the anti-inflammatory and angiogenic effects of CBD. Furthermore, we found that compared with MDSCs in the normal group, CBD-induced MDSCs overexpress peroxisome proliferator-activated receptor-gamma (PPAR-γ). Administering PPAR-γ inhibitor in mice almost reversed the induction of MDSCs by CBD, demonstrating the role of PPAR-γ in the function of CBD.

CONCLUSION

This study indicates that CBD may induce MDSCs upregulation by activating the nuclear receptor PPAR-γ, exerting anti-inflammatory, antiangiogenic, and lymphangiogenic effects, and revealing potential therapeutic targets for corneal neovascularization and lymphangiogenesis.

Causes of Corneal Melt After the Boston Keratoprosthesis Type I: The Chinese People's Liberation Army General Hospital Experience

PURPOSE

The purpose of this study was to evaluate the long-term incidence, risk factors, and the management of corneal melt following Boston type I keratoprosthesis (B-KPro I) implantation.

METHODS

This is a retrospective observational case series. Data were collected regarding demographics, preoperative characteristics, incidence, and outcomes of corneal melt in 102 patients who underwent B-KPro I in the Chinese PLA General Hospital between 2011 and 2018, with a follow-up period ranging from 4 to 11 years.

RESULTS

Chemical burn was the most common indication for B-KPro I (n = 56; 53.8%), followed by ocular trauma (n = 26; 25.0%). During the follow-up period (107 ± 25.7 months), corneal melt occurred in 60 cases among 37 eyes (35.6%), with an incidence of 20.2% at 1 year after surgery. Fourteen cases presented with recurrent corneal melt. Patients with multiple corneal allograft failures had a higher risk of corneal melt. Thermal burns, compared with alkali burns, significantly elevated the odds ratio (OR) of corneal melt (OR, 5.11; 95% confidence interval, 1.05-24.86; P = 0.043).

CONCLUSIONS

Corneal melt significantly reduced the retention time of KPro ( P < 0.01), and its coexistence with other complications further shortened the retention time. A specific pattern of corneal melt occurrence was identified, with a peak incidence at 1 year postoperatively. Our findings suggest variations in the risk of corneal melt among different indications, with thermal burns carrying the highest OR. Moreover, each previous failed keratoplasty doubled the risk of corneal melt after B-KPro I.

Topical erythropoietin for the management of scleral necrosis after ocular chemical burns

PURPOSE

To evaluate the efficacy of topical erythropoietin for chemical burn induced scleral necrosis.

METHODS

This study included 18 eyes of 16 patients with chemical burn induced scleral necrosis who presented within 6 weeks of the injury. In the prospective arm, 11 eyes received topical erythropoietin, 3000 IU/mL every 6 h, along with standard medical treatment. Retrospectively, we included 7 consecutive eyes of 7 patients who were managed with conventional treatment as historical control group. The main outcome measure was healing of avascular scleral lesions. The secondary outcome measure was complete re-epithelization of cornea.

RESULTS

Mean patient age was 39.8 ± 16.2 years in the erythropoietin group, and they presented 16.6 ± 15.2 days after acute chemical injury. Scleral necrosis improved in all eyes after 30.7 ± 23.2 days of treatment with topical erythropoietin. Corneal epithelial defects were completely healed in 10 eyes 61.9 ± 50.7 days after the start of the medication. In comparison, standard medical treatment alone did not improve scleral necrosis in the historical control group, necessitating ocular surface reconstruction including conjunctival advancement (1 eye) and tenonplasty (6 eyes).

CONCLUSION

The results of our study showed that topical erythropoietin was effective in the management of chemical burn induced scleral necrosis. This treatment could avoid ocular surface reconstruction procedures in inflamed eyes.

LSD1 inhibition by tranylcypromine hydrochloride reduces alkali burn-induced corneal neovascularization and ferroptosis by suppressing HIF-1α pathway

Background

Corneal neovascularization (CNV) is a sight-threatening condition that necessitates epigenetic control. The role of lysine-specific demethylase 1 (LSD1) in CNV remains unclear, despite its established significance in tumor angiogenesis regulation.

Methods

An alkali burn-induced CNV mouse model was used in vivo. The effects of LSD1 inhibitor tranylcypromine hydrochloride (TCP) were examined through slit lamp, histological staining, and immunofluorescence. The expression of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH) levels were assessed in corneal tissues. Oxidative stress and ferrous ion expression during CNV were determined using 4-HNE, GPX4, and FerroOrange staining. In vitro, a hypoxia-reoxygenation (H/R) model was established using human umbilical vein endothelial cells (HUVECs) to study LSD1 or hypoxia-inducible factor (HIF-1α) knockdown and lentiviral overexpression of HIF-1α. The effects on HUVECs migration, invasion, and angiogenesis were evaluated through cell scratching assay, transwell migration assay and tube formation assay. The role of ferroptosis was investigated using ROS staining, FerroOrange staining, and key ferroptosis proteins. Further, The JAK2/STAT3 pathway's involvement in CNV regulation was explored through in vivo experiments with subconjunctival injection of AG490.

Results

The results showed a substantial correlation between corneal damage and LSD1 levels. In addition, HIF-1α expression was also elevated after alkali burns, and subconjunctival injection of TCP reduced corneal inflammation and neovascularization. Corneal alkali burns increased ROS levels and reduced antioxidative stress indicators, accompanied by elevated ferrous ion levels, which were reversed by TCP injection. In vitro, TCP or siRNAs inhibited H/R-induced ferroptosis and angiogenesis in HUVECs by affecting specific protein expressions and MDA, SOD, and GSH levels. HIF-1α levels, associated with ROS production, ferroptosis, and angiogenesis, increased during H/R, but were reversed by TCP or siRNA administration. HIF-1α overexpression counteracted the effects of LSD1 inhibition. Additionally, AG490 injection effectively reduced HIF-1α and VEGFA expression in the CNV model.

Discussion

These findings suggest that LSD1 inhibition via the HIF-1α-driven pathway prevents angiogenesis, oxidative stress, and ferroptosis in corneal alkali burn-induced CNV, highlighting LSD1 as a potential therapeutic target.

Engineered Mesenchymal Stromal Cell Exosomes-Loaded Microneedles Improve Corneal Healing after Chemical Injury

Corneal alkali burns represent a prevalent ophthalmic emergency with the potential to induce blindness. The main contributing mechanisms include excessive inflammation and delayed wound healing. Existing clinical therapies have limitations, promoting the exploration of alternative methods that offer improved efficacy and reduced side effects. Adipose-derived stem cell-exosome (ADSC-Exo) has the potential to sustain immune homeostasis and facilitate tissue regeneration. Nevertheless, natural ADSC-Exo lacks disease specificity and exhibits limited bioavailability on the ocular surface. In this study, we conjugated antitumor necrosis factor-α antibodies (aT) to the surface of ADSC-Exo using matrix metalloproteinase-cleavable peptide chains to create engineered aT-Exo with synergistic effects. In both in vivo and in vitro assessments, aT-Exo demonstrated superior efficacy in mitigating corneal injuries compared to aT alone, unmodified exosomes, or aT simply mixed with exosomes. The cleavable conjugation of aT-Exo notably enhanced wound healing and alleviated inflammation more effectively. Simultaneously, we developed poly(vinyl alcohol) microneedles (MNs) for precise and sustained exosome delivery. The in vivo results showcased the superior therapeutic efficiency of MNs compared with conventional topical administration and subconjunctival injection. Therefore, the bioactive nanodrugs-loaded MNs treatment presents a promising strategy for addressing ocular surface diseases.

Development of an injectable oxidized dextran/gelatin hydrogel capable of promoting the healing of alkali burn-associated corneal wounds

The cornea serves as an essential shield that protects the underlying eye from external conditions, yet it remains highly vulnerable to injuries that could lead to blindness and scarring if not promptly and effectively treated. Excessive inflammatory response constitute the primary cause of pathological corneal injury. This study aimed to develop effective approaches for enabling the functional repair of corneal injuries by combining nanoparticles loaded with anti-inflammatory agents and an injectable oxidized dextran/gelatin/borax hydrogel. The injectability and self-healing properties of developed hydrogels based on borate ester bonds and dynamic Schiff base bonds were excellent, improving the retention of administered drugs on the ocular surface. In vitro cellular assays and in vivo animal studies collectively substantiated the proficiency of probucol nanoparticle-loaded hydrogels to readily suppress proinflammatory marker expression and to induce the upregulation of anti-inflammatory mediators, thereby supporting rapid repair of rat corneal tissue following alkali burn-induced injury. As such, probucol nanoparticle-loaded hydrogels represent a prospective avenue to developing long-acting and efficacious therapies for ophthalmic diseases.

Recent advances in corneal neovascularization imaging

Corneal neovascularization (CoNV) is a vision-threatening ocular disease commonly secondary to infectious, inflammatory, and traumatic etiologies. Slit lamp photography, in vivo confocal microscopy, angiography, and optical coherence tomography angiography (OCTA) are the primary diagnostic tools utilized in clinical practice to evaluate the vasculature of the ocular surface. However, there is currently a dearth of comprehensive literature that reviews the advancements in imaging technology for CoNV administration. Initially designed for retinal vascular imaging, OCTA has now been expanded to the anterior segment and has shown promising potential for imaging the conjunctiva, cornea, and iris. This expansion allows for the quantitative monitoring of the structural and functional changes associated with CoNV. In this review, we emphasize the impact of algorithm optimization in anterior segment-optical coherence tomography angiography (AS-OCTA) on the diagnostic efficacy of CoNV. Through the analysis of existing literature, animal model assessments are further reported to investigate its pathological mechanism and exhibit remarkable therapeutic interventions. In conclusion, AS-OCTA holds broad prospects and extensive potential for clinical diagnostics and research applications in CoNV.

Trimebutine prevents corneal inflammation in a rat alkali burn model

Alkaline burns to the cornea lead to loss of corneal transparency, which is essential for normal vision. We used a rat corneal alkaline burn model to investigate the effect of ophthalmic trimebutine solution on healing wounds caused by alkaline burns. Trimebutine, an inhibitor of the high-mobility group box 1-receptor for advanced glycation end products, when topically applied to the burned cornea, suppressed macrophage infiltration in the early phase and neutrophil infiltration in the late phase at the wound site. It also inhibited neovascularization and myofibroblast development in the late phase. Furthermore, trimebutine effectively inhibited interleukin-1β expression in the injured cornea. It reduced scar formation by decreasing the expression of type III collagen. These findings suggest that trimebutine may represent a novel therapeutic strategy for corneal wounds, not only through its anti-inflammatory effects but also by preventing neovascularization.

Evaluation of the Treatment Effects of Conditioned Medium from Human Orbital Adipose-Derived Stem Cells in a Corneal Alkali Burn Rabbit Model

Purpose: This study aimed to evaluate the effects of a new treatment-conditioned medium from human orbital adipose-derived stem cells (OASC-CM)-on corneal recovery after alkali burns in a rabbit model. Methods: The corneal alkali burn rabbit model was established and treated with OASC-CM, conditioned medium from human abdominal subcutaneous adipose-derived stem cells (ABASC-CM), and fresh control culture medium (con-CM) three times a day for 7 days, respectively. Subsequently, the treatment effects were evaluated and compared through clinical, histological, immunohistochemical, and cytokine evaluations. Results: Clinically, OASC-CM alleviated corneal opacity and edema and promoted recovery of corneal epithelium defect. Histologically and immunohistochemically, OASC-CM inhibited neovascularization, conjunctivalization, and immuno-inflammatory reaction, while promoting corneal regeneration and rearrangement. Increased secretion of interleukin-10 and inhibited protein levels of cluster of differentiation 45, interferon-γ, and tumor necrosis factor-α were observed in the alkali-burned cornea after OASC-CM treatment, which might be the relevant molecular mechanism. Conclusions: OASC-CM showed significant effects on the recovery of rabbit corneal alkali burns and eliminated immunological and ethical limitations, representing a new option for corneal wound treatment.

Tissue-targeted and localized AAV5-DCN and AAV5-PEDF combination gene therapy abrogates corneal fibrosis and concurrent neovascularization in rabbit eyes in vivo

PURPOSE

Corneal fibrosis and neovascularization (CNV) after ocular trauma impairs vision. This study tested therapeutic potential of tissue-targeted adeno-associated virus5 (AAV5) mediated decorin (DCN) and pigment epithelium-derived factor (PEDF) combination genes in vivo.

METHODS

Corneal fibrosis and CNV were induced in New Zealand White rabbits via chemical trauma. Gene therapy in stroma was delivered 30-min after chemical-trauma via topical AAV5-DCN and AAV5-PEDF application using a cloning cylinder. Clinical eye examinations and multimodal imaging in live rabbits were performed periodically and corneal tissues were collected 9-day and 15-day post euthanasia. Histological, cellular, and molecular and apoptosis assays were used for efficacy, tolerability, and mechanistic studies.

RESULTS

The AAV5-DCN and AAV5-PEDF combination gene therapy significantly reduced corneal fibrosis (p < 0.01 or p < 0.001) and CNV (p < 0.001) in therapy-given (chemical-trauma and AAV5-DCN + AAV5-PEDF) rabbit eyes compared to the no-therapy given eyes (chemical-trauma and AAV5-naked vector). Histopathological analyses demonstrated significantly reduced fibrotic α-smooth muscle actin and endothelial lectin expression in therapy-given corneas compared to no-therapy corneas on day-9 (p < 0.001) and day-15 (p < 0.001). Further, therapy-given corneas showed significantly increased Fas-ligand mRNA levels (p < 0.001) and apoptotic cell death in neovessels (p < 0.001) compared to no-therapy corneas. AAV5 delivered 2.69 × 107 copies of DCN and 2.31 × 107 copies of PEDF genes per μg of DNA. AAV5 vector and delivered DCN and PEDF genes found tolerable to the rabbit eyes and caused no significant toxicity to the cornea.

CONCLUSION

The combination AAV5-DCN and AAV5-PEDF topical gene therapy effectively reduces corneal fibrosis and CNV with high tolerability in vivo in rabbits. Additional studies are warranted.

Burn related globe and adnexal trauma at trauma centres

INTRODUCTION

Prompt management of burn-related globe trauma can prevent long term complications. Delays in diagnosis may occur when globe trauma is associated with life-threatening injuries. We aimed to improve the understanding of the epidemiology, acute assessment and management of burns-related globe and adnexal trauma admitted to two trauma centres in Sydney, Australia.

METHOD

Admitted patients with burns-related globe and/or adnexal trauma were retrospectively reviewed at Royal North Shore Hospital (RNSH) and Royal Prince Alfred Hospital (RPAH) between January 2015 and December 2019. The International Classification of Disease, Tenth Revision codes was used to search and identify patients. Medical records were reviewed to extract data on demographics, injuries, ocular examination and ophthalmology involvement.

RESULTS

Over the 5-years, 101 patients with globe and/or adnexal burns-related trauma were admitted to RNSH or RPAH. Median age was 37years. Most patients were male (76%) and were injured while at home or work (74%). Patients with chemical exposure were more likely to have globe trauma (100% vs 72%, p < 0.001) and severe globe trauma (54% vs 32%, p = 0.028). On initial review by emergency staff, 14 patients were not referred to ophthalmology, of these there were 2 patients where the diagnosis was delayed.

CONCLUSION

Globe trauma is common in patients with chemical exposure. Thorough ocular assessment within the acute setting is vital to diagnose globe trauma. We investigated hospitals with specialised burn staff, further research is required to understand the management of globe trauma in hospitals without such resources.

SYNOPSIS

Chemicals in household-products can cause severe globe trauma. Globe trauma can occur alongside large burns leading to delay in its diagnosis and management. Ophthalmology can assist in the early diagnosis and management of globe trauma.

Natural compounds efficacy in Ophthalmic Diseases: A new twist impacting ferroptosis

Ferroptosis, a distinct form of cell death, is characterized by the iron-mediated oxidation of lipids and is finely controlled by multiple cellular metabolic pathways. These pathways encompass redox balance, iron regulation, mitochondrial function, as well as amino acid, lipid, and sugar metabolism. Additionally, various disease-related signaling pathways also play a role in the regulation of ferroptosis. In recent years, with the introduction of the concept of ferroptosis and the deepening of research on its mechanism, ferroptosis is closely related to various biological conditions of eye diseases, including eye organ development, aging, immunity, and cancer. This article reviews the development of the concept of ferroptosis, the mechanism of ferroptosis, and its latest research progress in ophthalmic diseases and reviews the research on ferroptosis in ocular diseases within the framework of metabolism, active oxygen biology, and iron biology. Key regulators and mechanisms of ferroptosis in ocular diseases introduce important concepts and major open questions in the field of ferroptosis and related natural compounds. It is hoped that in future research, further breakthroughs will be made in the regulation mechanism of ferroptosis and the use of ferroptosis to promote the treatment of eye diseases. At the same time, natural compounds may be the direction of new drug development for the potential treatment of ferroptosis in the future. Open up a new way for clinical ophthalmologists to research and prevent diseases.

Dexamethasone and MicroRNA-204 Inhibit Corneal Neovascularization

INTRODUCTION

This was an in vivo animal study designed to investigate the interaction between dexamethasone (Dex) and microRNA-204 (miR-204) in a mouse alkali burn-induced corneal neovascularization (CNV) model. The function of miR-204 was then investigated in human mammary epithelial cells (HMECs) in vitro.

MATERIALS AND METHODS

The CNV model was induced by corneal alkali burn in BLAB/c mice. The mice were randomly divided into five groups: normal control (Ctrl), alkali burn-induced corneal injury (Alkali), alkali burn + Dex (Dex), alkali burn + negative control (NTC), and alkali burn + miR-204 agomir (miR-204). Subconjunctival injection of NTC, Dex, or miR-204 agomir was conducted at 0, 3, and 6 days, respectively, after alkali burn. The corneas were collected at day 7 after injury, and the CNV area was observed using immunofluorescence staining. The expression of miR-204 was analyzed with quantitative real time (qRT)-PCR. In HMECs, exogenous miR-204 agomir or antagomir was used to strengthen or inhibit the expression of miR-204. Migration assays and tube formation studies were conducted to evaluate the function of miR-204 on HMECs.

RESULTS

At 7 days post-alkali burn, CNV grew aggressively into the cornea. MicroRNA-204 expression was reduced in the Alkali group in contrast with the Ctrl group (P = .003). However, miR-204 was upregulated in the Dex group (vs. alkali group, P = .008). The CNV areas in the NTC and miR-204 groups were 59.30 ± 8.32% and 25.60 ± 2.30%, respectively (P = .002). In vitro, miR-204 agomir showed obvious inhibition on HMEC migration in contrast with NTC (P = .033) and miR-204 antagomir (P = .017). Compared with NTC, miR-204 agomir attenuated tube formation, while miR-204 antagomir accelerated HMEC tube formation (P < .05).

CONCLUSION

The role of Dex in attenuating CNV may be partly attributed to miR-204. MiR-204 may be a potential therapeutic target in alkali burn-induced CNV.

Incidents of Occupational Ocular Injuries in Industrial Settings: Highlighting the Critical Significance of Protective Eye Gear

SUMMARY

We present four cases of ocular surface and adnexal appendage injuries resulting from exposure to hazardous materials in various industrial occupations. These injuries occurred due to the absence of protective eye equipment while working. Emphasizing the irrefutable importance of protective eye gear is the aim of this article as it is crucial to mitigate such unfortunate incidents.

Smart coating by thermo-sensitive Pluronic F-127 for enhanced corneal healing via delivery of biological macromolecule progranulin

As a leading cause of vision impairment and blindness, corneal alkali burns lead to long-term visual deterioration or even permanent visual impairment while effective treatment strategies remain a challenge. Herein, a thermo-sensitive hydrogel with the combination of multi-functional protein progranulin (PGRN), a biological macromolecule consisting of several hundred amino acids and possessing a high molecular weight, is efficiently prepared through a convenient stirring and mixing at the low temperature. The hydrogel can be easily administrated to the ocular surface contacting with the cornea, which can be immediately transformed into gel-like state due to the thermo-responsive behavior, realizing a site-specific coating to isolate further external stimulation. The smart coating not only exhibits excellent transparency and biocompatibility, but also presents a constant delivery of PGRN, creating a nutritious and supportive micro-environment for the ocular surface. The results show that the prepared functional hydrogel can efficiently suppress inflammation, accelerate re-epithelization, and intriguingly enhance axonal regeneration via modulation of multiple signaling pathways, indicating the novel designed HydrogelPGRN is a promising therapy option for serious corneal injury.

A moderate dosage of prostaglandin E2-mediated annexin A1 upregulation promotes alkali-burned corneal repair

Corneal alkali burn remains a clinical challenge in ocular emergency, necessitating the development of effective therapeutic drugs. Here, we observed the arachidonic acid metabolic disorders of corneas induced by alkali burns and aimed to explore the role of Prostaglandin E2 (PGE2), a critical metabolite of arachidonic acid, in the repair of alkali-burned corneas. We found a moderate dosage of PGE2 promoted the alkali-burned corneal epithelial repair, whereas a high dosage of PGE2 exhibited a contrary effect. This divergent effect is attributed to different dosages of PGE2 regulating ANXA1 expression differently. Mechanically, a high dosage of PGE2 induced higher GATA3 expression, followed by enhanced GATA3 binding to the ANXA1 promoter to inhibit ANXA1 expression. In contrast, a moderate dosage of PGE2 increased CREB1 phosphorylation and reduced GATA3 binding to the ANXA1 promoter, promoting ANXA1 expression. We believe PGE2 and its regulatory target ANXA1 could be potential drugs for alkali-burned corneas.

Myeloid-derived suppressor cells ameliorate corneal alkali burn through IL-10-dependent anti-inflammatory properties

This study aims to investigate the efficiency and the underlying mechanism of myeloid-derived suppressor cells (MDSCs) in corneal alkali burns (CAB). In the study, CD11b+ Gr-1+ cells from C57BL/6J mice bone marrow were cultured and induced. Cell activity and immunoregulatory function were assessed by flow cytometry in vitro. The optimal strategy of MDSCs therapy was assessed by slit-lamp microscopy, and flow cytometry in vivo. The therapeutic effects of MDSCs and the critical signaling pathway were investigated by hematoxylin-eosin (HE) staining, slit-lamp microscopy, flow cytometry, and immunofluorescence. The expression level of the NLRP3 inflammasome pathway was examined. The crucial biochemical parameters of MDSCs were examined by RNA-seq and qPCR to screen out the key regulators. The mechanism of MDSCs' therapeutic effects was explored using MDSCs with IL-10 knockout/rescue by slit-lamp microscopy, HE staining, and qPCR evaluation. The cell frequencies of macrophages and neutrophils in the cornea were examined by flow cytometry in vivo. The results demonstrated that the induced MDSCs meet the standard of phenotypic and functional characteristics. The treatment of 5 × 105 MDSCs conjunctival injection on alternate days significantly ameliorated the disease development, downregulated the NLRP3 inflammasome pathway, and decreased the cell frequencies of macrophages and neutrophils in vivo significantly. IL-10 was screened out to be the critical factor for MDSCs therapy. The therapeutic effects of MDSCs were impaired largely by IL-10 knock-out and saved by the IL-10 supplement. In conclusion, MDSCs therapy is a promising therapeutic solution for CAB. MDSCs fulfilled immunoregulatory roles for CAB by IL-10-dependent anti-inflammatory properties.

TFOS Lifestyle Report: Impact of environmental conditions on the ocular surface

Environmental risk factors that have an impact on the ocular surface were reviewed and associations with age and sex, race/ethnicity, geographical area, seasonality, prevalence and possible interactions between risk factors are reviewed. Environmental factors can be (a) climate-related: temperature, humidity, wind speed, altitude, dew point, ultraviolet light, and allergen or (b) outdoor and indoor pollution: gases, particulate matter, and other sources of airborne pollutants. Temperature affects ocular surface homeostasis directly and indirectly, precipitating ocular surface diseases and/or symptoms, including trachoma. Humidity is negatively associated with dry eye disease. There is little data on wind speed and dewpoint. High altitude and ultraviolet light exposure are associated with pterygium, ocular surface degenerations and neoplastic disease. Pollution is associated with dry eye disease and conjunctivitis. Primary Sjögren syndrome is associated with exposure to chemical solvents. Living within a potential zone of active volcanic eruption is associated with eye irritation. Indoor pollution, "sick" building or house can also be associated with eye irritation. Most ocular surface conditions are multifactorial, and several environmental factors may contribute to specific diseases. A systematic review was conducted to answer the following research question: "What are the associations between outdoor environment pollution and signs or symptoms of dry eye disease in humans?" Dry eye disease is associated with air pollution (from NO2) and soil pollution (from chromium), but not from air pollution from CO or PM10. Future research should adequately account for confounders, follow up over time, and report results separately for ocular surface findings, including signs and symptoms.

Demographic profile and clinical characteristics of patients presenting with acute ocular burns

Purpose

To study and compare the demographic and clinical profile of acute ocular burns (AOB) in children and adults.

Methods

This retrospective case series included 271 children (338 eyes) and 1300 adults (1809 eyes) who presented to two tertiary eye care centers within one month of sustaining AOB. Data regarding demographics, causative agents, severity of injury, visual acuity (VA), and treatment were collected and analyzed.

Results

Males were more commonly affected particularly among adults (81% versus 64%, P < 0.00001). Among children, 79% sustained domestic injuries, whereas 59% of adults had work-place injuries (P < 0.0001). Most cases were due to alkali (38%) and acids (22%). Edible lime (chuna, 32%), superglue (14%), and firecrackers (12%) in children, and chuna (7%), insecticides, lye, superglue (6% each), toilet cleaner (4%) and battery acid (3%) in adults, were the main causative agents. The percentage of cases with Dua grade IV-VI was greater in children (16% versus 9%; P = 0.0001). Amniotic membrane grafting and/or tarsorrhaphy were needed in 36% and 14% of affected eyes in children and adults, respectively (P < 0.00001). The median presenting VA was logMAR 0.5 in children and logMAR 0.3 in adults (P = 0.0001), which improved significantly with treatment in both groups (P < 0.0001), but the final VA in eyes with Dua grade IV-VI burns was poorer in children (logMAR 1.3 versus logMAR 0.8, P = 0.04).

Conclusion

The findings clearly delineate the at-risk groups, causative agents, clinical severity, and treatment outcomes of AOB. Increased awareness and data-driven targeted preventive strategies are needed to reduce the avoidable ocular morbidity in AOB.

Upadacitinib inhibits corneal inflammation and neovascularization by suppressing M1 macrophage infiltration in the corneal alkali burn model

Alkali burn-induced corneal inflammation and subsequent corneal neovascularization (CNV) are major causes of corneal opacity and vision loss. M1 macrophages play a central role in inflammation and CNV. Therefore, modulation of M1 macrophage polarization is a promising strategy for corneal alkali burns. Here, we illustrate the effect and underlying mechanisms of upadacitinib on corneal inflammation and CNV induced by alkali burns in mice. The corneas of BALB/c mice were administered with 1 M NaOH for 30 s and randomly assigned to the vehicle group and the upadacitinib-treated group. Corneal opacity and corneal epithelial defects were assessed clinically. Quantitative real-time PCR (qRT-PCR), immunohistochemistry, and western blot analysis were performed to detect M1 macrophage polarization and CD31⁺ corneal blood vessels. The results showed that upadacitinib notably decreased corneal opacity, and promoted corneal wound healing. On day 7 and 14 after alkali burns, upadacitinib significantly suppressed CNV. Corneal alkali injury caused M1 macrophage recruitment in the cornea. In contrast to the vehicle, upadacitinib suppressed M1 macrophage infiltration and decreased the mRNA expression levels of inducible nitric oxide synthase (iNOS), monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-1β, and vascular endothelial growth factor A (VEGF-A) in alkali-injured corneas. Moreover, upadacitinib dose-dependently inhibited M1 macrophage polarization by suppressing interferon (IFN)-γ-/lipopolysaccharide-stimulated STAT1 activation in vitro. Our findings reveal that upadacitinib can efficiently alleviate alkali-induced corneal inflammation and neovascularization by inhibiting M1 macrophage infiltration. These data demonstrate that upadacitinib is an effective drug for the treatment of corneal alkali burns.