Alkali-Related Ocular Burns: A Case Series and Review

Neutrophil pyroptosis regulates corneal wound healing and post-injury neovascularisation

RATIONALE

The cornea is a unique structure that maintains its clarity by remaining avascular. Corneal injuries can lead to neovascularisation (CNV) and fibrosis and are the third most common cause of blindness worldwide.

OBJECTIVE

Corneal injuries induce an immune cell infiltration to initiate reparative processes. However, inflammation caused by sustained immune cell infiltration is known to be detrimental and can delay the healing process. This study was designed to understand the potential role of neutrophil and epithelial cell crosstalk in post-injury CNV.

METHODS AND RESULTS

Western blotting and immunostaining assays demonstrated that neutrophils infiltrated corneas and underwent pyroptosis following acute alkali injury. In vivo studies showed that genetic ablation of Gasdermin D (GsdmD), a key effector of pyroptosis, enhanced corneal re-epithelialisation and suppressed post-injury CNV. In vitro co-culture experiments revealed that interleukin-1β (IL-1β) was released from pyroptotic neutrophils which suppressed migration of murine corneal epithelial cells. Real-time RT-PCR and immunostaining assays identified two factors, Wnt5a and soluble fms-like tyrosine kinase-1 (sflt-1), highly expressed in newly healed epithelial cells. sflt-1 is known to promote corneal avascularity. Bone marrow transplantation, antibody mediated neutrophil depletion, and pharmacological inhibition of pyroptosis promoted corneal wound healing and inhibited CNV in an in vivo murine corneal injury model.

CONCLUSION

Taken together, our study reveals the importance of neutrophil/epithelium crosstalk and neutrophil pyroptosis in response to corneal injuries. Inhibition of neutrophil pyroptosis may serve as a potential treatment to promote corneal healing without CNV.

KEY POINTS

Neutrophil pyroptosis delays re-epithelialization after corneal injury Compromised re-epithelialization promotes corneal neovascularization after injury Inhibition of post-injury pyroptosis could be an effective therapy to promote corneal wound healing.

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.

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.

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.

Transitory alkali exposure on meibomian gland orifices induces meibomian gland dysfunction

PURPOSE

To determine pathological changes of meibomian glands (MGs) after transient exposure of the rat eyelid margin to alkali solution.

METHODS

Filter paper infiltrated with 1 N sodium hydroxide solution was applied to the eyelid margin of Sprague-Dawley rats for 30 s under general anesthesia, without touching the conjunctiva, after which the ocular surface and eyelid margin were examined by slit-lamp microscopy. In vivo confocal microscopy and stereomicroscopy were subsequently applied to observe MG morphology on day 5, day 10 and day 30 post alkali injury. Eyelid cross-sections were processed for H&E staining, Oil red O staining and immunofluorescent staining.

RESULTS

After alkali injury, there was marked plugging of MG orifices, telangiectasia and hypertrophy of the eyelid margin, while corneal epithelium was intact at post-injury days 5 and 10. However, 30 days after alkali injury, mild corneal epithelial damage was observed. Degeneration of MG acini was observed at days 5 and became aggravated at days 10 and 30, along with MG duct dilation and acini loss. Oil red O staining showed lipid accumulation in the dilated duct. Inflammatory cell infiltration and the presence of apoptotic cells was seen in the MG loci 5 days post injury, but diminished at days 10 and 30. Cytokeratin 10 expression was increased in dilated duct, while cytokeratin 14, PPAR-γ, Ki67 and LRIG1 expression were decreased in the acini of injured loci.

CONCLUSIONS

Transitory alkali exposure of the rat eyelid margin obstructs the MG orifice and induces pathological changes of MG dysfunction.

Epidemiology and etiology of chemical ocular injury: A brief review

Chemical ocular injury is one of the common ophthalmologic emergencies that can cause vision loss and serious complications. Despite all protective measures, it continues to be a serious public health problem, especially in young male patients. Although it is known that injuries occur most frequently in the workplace and in young male patients, there is a variable frequency and distribution in different regions around the world. In addition, with the coronavirus disease 2019 pandemic, there are changing trends in ocular chemical injuries. This review aims to specify an update on the epidemiological and etiological features of ocular chemical injuries.

MiRNA 24-3p-rich exosomes functionalized DEGMA-modified hyaluronic acid hydrogels for corneal epithelial healing

The damage of corneal epithelium may lead to the formation of irreversible corneal opacities and even blindness. The migration rate of corneal epithelial cells directly affects corneal repair. Here, we explored ocu-microRNA 24-3p (miRNA 24-3p) that can promote rabbit corneal epithelial cells migration and cornea repair. Exosomes, an excellent transport carrier, were exacted from adipose derived mesenchymal stem cells for loading with miRNA 24-3p to prepare miRNA 24-3p-rich exosomes (Exos-miRNA 24-3p). It can accelerate corneal epithelial migration in vitro and in vivo. For application in cornea alkali burns, we further modified hyaluronic acid with di(ethylene glycol) monomethyl ether methacrylate (DEGMA) to obtain a thermosensitive hydrogel, also reported a thermosensitive DEGMA-modified hyaluronic acid hydrogel (THH) for the controlled release of Exos-miRNA 24-3p. It formed a highly uniform and clear thin layer on the ocular surface to resist clearance from blinking and extended the drug-ocular-epithelium contact time. The use of THH-3/Exos-miRNA 24-3p for 28 days after alkali burn injury accelerated corneal epithelial defect healing and epithelial maturation. It also reduced corneal stromal fibrosis and macrophage activation. MiRNA 24-3p-rich exosomes functionalized DEGMA-modified hyaluronic acid hydrogel as a multilevel delivery strategy has a potential use for cell-free therapy of corneal epithelial regeneration.

Trends and characteristics of ocular exposures related to e-cigarettes and e-liquids reported to Poison Control Centers in the United States, 2010-2019

INTRODUCTION

Ocular injuries and unintended exposures involving electronic nicotine delivery systems (ENDS), also known as e-cigarettes, have been reported. However, trends and characteristics of ENDS-related ocular exposures at the population level are not well documented. This study was designed to describe trends and characteristics of ENDS-related ocular exposure cases reported to poison control centers (PCCs) in the U.S.

METHODS

We computed descriptive statistics of ENDS-related ocular exposure cases reported to PCCs between January 1, 2010 and December 31, 2019, including number of cases per year and the distribution of characteristics of those cases. We also summarized case narrative review findings.

RESULTS

A total of 1,393 ENDS-related ocular exposure cases were reported to PCCs during the study period. Overall number of cases increased from two in 2010 to a peak of 389 in 2014, followed by a steady decline in 2015-2018. Of the 1,393 cases, 42.5% occurred among individuals aged 25 years and older; 20.4 and 17.7% occurred among young adults aged 18-24 years and children younger than five years, respectively. Nearly one quarter (23.8%) of the individuals experiencing ocular exposure sought or were recommended to seek medical attention. Case narrative review found that 59 of 127 (46.5%) cases were due, at least in part, to incorrect use or handling of the products.

DISCUSSION AND CONCLUSIONS

Our study shows that more than 1,000 ENDS-related ocular exposure cases were reported to PCCs during the study period. Many of these cases involved young children; nearly half were due, at least in part, to incorrect use or handling of the products. Future efforts to prevent these exposures may focus on improving the awareness of the potential harmful effects of ENDS products and the importance of appropriate handling of ENDS products. Health care professionals may play an important role in educating patients and improving surveillance of ENDS-related ocular exposure cases.

Immunity and pain in the eye: focus on the ocular surface

Most ocular diseases are associated with pain. While pain has been generally considered a mere (deleterious) additional symptom, it is now emerging that it is a key modulator of innate/adaptive immunity. Because the cornea receives the highest nerve density of the entire body, it is an ideal site to demonstrate interactions between pain and the immune response. Indeed, most neuropeptides involved in pain generation are also potent regulators of innate and adaptive leukocyte physiology. On the other hand, most inflammatory cells can modulate the generation of ocular pain through release of specific mediators (cytokines, chemokines, growth factors, and lipid mediators). This review will discuss the reciprocal role(s) of ocular surface (and specifically: corneal) pain on the immune response of the eye. Finally, we will discuss the clinical implications of such reciprocal interactions in the context of highly prevalent corneal diseases.

Fibrin-Plasma Rich in Growth Factors Membrane for the Treatment of a Rabbit Alkali-Burn Lesion

The purpose of this work is to describe the use of Fibrin-Plasma Rich in Growth Factors (PRGF) membranes for the treatment of a rabbit alkali-burn lesion. For this purpose, an alkali-burn lesion was induced in 15 rabbits. A week later, clinical events were evaluated and rabbits were divided into five treatment groups: rabbits treated with medical treatment, with a fibrin-PRGF membrane cultured with autologous or heterologous rabbit Limbal Epithelial Progenitor Cells (LEPCs), with a fibrin-PRGF membrane in a Simple Limbal Epithelial Transplantation and with a fibrin-PRGF membrane without cultured LEPCs. After 40 days of follow-up, corneas were subjected to histochemical examination and immunostaining against corneal or conjunctival markers. Seven days after alkali-burn lesion, it was observed that rabbits showed opaque cornea, new blood vessels across the limbus penetrating the cornea and epithelial defects. At the end of the follow-up period, an improvement of the clinical parameters analyzed was observed in transplanted rabbits. However, only rabbits transplanted with cultured LEPCs were positive for corneal markers. Otherwise, rabbits in the other three groups showed positive staining against conjunctival markers. In conclusion, fibrin-PRGF membrane improved the chemically induced lesions. Nonetheless, only fibrin-PRGF membranes cultured with rabbit LEPCs were able to restore the corneal surface.

Epidemiology, economic and humanistic burdens of Ocular Surface Chemical Injury: A narrative review

Ocular surface chemical injury (OSCI) is a common type of ocular emergency that can potentially cause significant and permanent visual impairment. However, the global prevalence, demographic factors, socioeconomic burden, and psychological impact of OSCI have not been well investigated or reported. This review aims to provide a comprehensive overview of these aspects, highlight gaps in the literature, and advocate key strategies in reducing the incidence of OSCI. OSCI was responsible for 0.1-15% of all ocular emergency presentations, with an estimated incidence of 5.1-50 per 100,000 population-year. Young working adult men were the most at-risk group, though high rates of OSCI were also observed in young children in developed countries, especially from detergent pods. Low- and middle-income countries were noted to have higher proportions of assault-related and pediatric OSCI cases, often with more severe presentations. Direct and indirect costs for some hospitalized patients led to loss of all personal and household income after the injury. Emergency department costs in the United States were estimated at $106.7 million over four years and costs of treating long term complications such as glaucoma were estimated to be as high as $93,003 over five years. Significant negative impacts on visual and health-related quality of life and psychological well-being have been reported after injury, with higher rates of anxiety, depression, and psychological distress compared to the general population.

Effect of mesenchymal stromal cells encapsulated within polyethylene glycol-collagen hydrogels formed in situ on alkali-burned corneas in an ex vivo organ culture model

BACKGROUND AIMS

Corneal inflammation after alkali burns often results in vision loss due to corneal opacification and neovascularization. Mesenchymal stem cells (MSCs) and their secreted factors (secretome) have been studied for their anti-inflammatory and anti-angiogenic properties with encouraging results. However, topical instillation of MSCs or their secretome is often accompanied by issues related to delivery or rapid washout. Polyethylene glycol (PEG) and collagen are well-known biomaterials used extensively in scaffolds for tissue engineering. To effectively suppress alkaline burn-induced corneal injury, the authors proposed encapsulating MSCs within collagen gels cross-linked with multi-functional PEG-succinimidyl esters as a means to deliver the secretome of immobilized MSCs.

METHODS

Human MSCs were added to a neutralized collagen solution and mixed with a solution of four-arm PEG-N-hydroxysuccinimide. An ex vivo organ culture was conducted using rabbit corneas injured by alkali burn. MSCs were encapsulated within PEG-collagen hydrogels and injected onto the wounded cornea immediately following alkali burn and washing. Photographs of the ocular surface were taken over a period of 7 days after the alkali burn and processed for immunohistochemical evaluation. Samples were split into three groups: injury without treatment, MSCs alone, and MSCs encapsulated within PEG-collagen hydrogels.

RESULTS

All corneas in ex vivo organ culture lost their transparency immediately after alkali burn, and only the groups treated with MSCs and MSCs encapsulated within PEG-collagen hydrogels recovered some transparency after 7 days. Immunohistochemical analysis revealed increased expression of vimentin in the anterior corneal stroma of the group without treatment indicative of fibrotic healing, whereas less stromal vimentin was detected in the group containing MSCs encapsulated within the PEG-collagen hydrogels.

CONCLUSIONS

PEG-collagen hydrogels enable the encapsulation of viable MSCs capable of releasing secreted factors onto the ocular surface. Encapsulating MSCs within PEG-collagen hydrogels may be a promising method for delivering their therapeutic benefits in cases of ocular inflammatory diseases, such as alkali burn injuries.

Management Strategies of Ocular Chemical Burns: Current Perspectives

Ocular chemical burns are absolute ophthalmic emergencies and require immediate management to minimize devastating sequelae. Management of alkali and acid burns is started at the scene of the accident by copious irrigation. Treatment is directed at improving epithelial integrity and stromal stability, reduction of undue inflammation, and prevention or timely management of complications. To ascertain the best possible outcome, numerous biological medications and surgical interventions have been merged into conventional therapeutic regimens. These include autologous and umbilical cord serum preparations, platelet-rich plasma, amniotic membrane transplantation, limbal stem-cell transplantation, and anti-angiogenic agents.

Clinical characteristics of patients hospitalized for ocular chemical injuries in Shanghai from 2012 to 2017

Purpose

To summarize the clinical characteristics of patients with ocular chemical injuries and evaluate their potential relationship with the visual outcome by analyzing the medical records of these patients from January 1, 2012, to December 31, 2017.

Methods

This is a retrospective case series study. Patient data included age, gender, occupational classification, location of ocular chemical injury, initial and final best-corrected distance visual acuity (BCDVA), intraocular pressure (IOP), nature and chemical phase, distribution and severity of chemical injury, management methods, and complications. All variables were evaluated for their potential relationship with visual outcome.

Results

A total of 160 patients were hospitalized with ocular chemical injuries. Majority of the patients were factory workers and arrived at the consultation room less than 24 h after injury. The most common ocular injury setting, classification of severity, causative chemical, chemical phase, and complications were workplace, grade II, unknown and mixed substance, liquid, and elevated IOP, respectively. The risk factors for poor final BCDVA were identified as older age, poor initial BCDVA, and irrigation 24 h after injury (P < 0.001, P < 0.001, and P = 0.011, respectively).

Conclusions

We elaborate the clinical characteristics and outcomes of patients with ocular chemical injuries in Jinshan District, Shanghai. A comprehensive education program should be established and the use of protective eyewear should be promoted to prevent occupation-related ocular chemical injuries.

Rescue of human corneal epithelial cells after alkaline insult using renalase derived peptide, RP-220

AIM

To study the effect of renalase peptide, RP-220, on cell viability of human corneal epithelial cells after alkali insult.

METHODS

A dose-response relationship between cell viability and exposure to NaOH solution were characterized using cultured human corneal epithelial cells. Viability of corneal epithelial cells was determined using commercially available MTT and CyQUANT^® assays.

RESULTS

At a concentration of 6 mmol/L, insult with NaOH leads to reduced corneal epithelial cell viability by approximately 30%. This reduced viability was prevented by treating the cells after initial insult with the 20-amino acid renalase derived peptide (RP-220).

CONCLUSION

RP-220 has a pro-survival role for RP-220 following alkaline insult to corneal epithelial cells.

Enhanced wound healing of tissue-engineered human corneas through altered phosphorylation of the CREB and AKT signal transduction pathways

The cornea is a transparent organ, highly specialized and unique that is continually subjected to abrasive forces and occasional mechanical or chemical trauma because of its anatomical localization. Upon injury, the extracellular matrix (ECM) rapidly changes to promote wound healing through integrin-dependent activation of specific signal transduction mediators whose contribution is to favor faster closure of the wound by altering the adhesive and migratory properties of the cells surrounding the damaged area. In this study, we exploited the human tissue-engineered cornea (hTECs) as a model to study the signal transduction pathways that participate to corneal wound healing. By exploiting both gene profiling and activated kinases arrays, we could demonstrate the occurrence of important alterations in the level of expression and activation of a few mediators from the PI3K/Akt and CREB pathways in response to the ECM remodeling taking place during wound healing of damaged hTECs. Pharmacological inhibition of CREB with C646 considerably accelerated wound closure compared to controls. This process was considerably accelerated further when both C646 and SC79, an Akt agonist, were added together to wounded hTECs. Therefore, our study demonstrate that proper corneal wound healing requires the activation of Akt together with the inhibition of CREB and that wound healing in vitro can be altered by the use of pharmacological inhibitors (such as C646) or agonists (such as SC79) of these mediators.

STATEMENT OF SIGNIFICANCE

Corneal wounds account for a large proportion of all visual disabilities in North America. To our knowledge, this is the first time that a tissue-engineered human cornea (hTEC) entirely produced using normal untransformed human cells is used as a biomaterial to study the signal transduction pathways that are critical to corneal wound healing. Through the use of this biomaterial, we demonstrated that human corneal epithelial cells engaged in wound healing reduce phosphorylation of the signal transduction mediator CREB while, in the mean time, they increase that of AKT. By increasing the activation of AKT together with a decrease in CREB activation, we could considerably reduce wound closure time in our punch-damaged hTECs. Considering the increasing interest given to the reconstruction of different types of tissues, we believe these results will have a strong impact on the field of tissue-engineering and biomaterials. Altering the activation status of the Akt and CREB proteins might prove to be a therapeutically interesting avenue and may also find applications in wound healing of other tissues beside the cornea, such as the skin.

Ocular surface inflammation impairs structure and function of meibomian gland

Dysfunction of the meibomian glands alters secreted meibum quantitatively and qualitatively that can lead to damage to the ocular surface epithelium. In response to an unstable tear film cause by meibomian gland dysfunction, ocular surface epithelium is damaged and expresses inflammatory cytokines leading to secondary ocular inflammation. In turn, inflammatory disorders of the palpebral conjunctiva and lid margin may affect the structure and function of meibomian gland. The disorders include allergic conjunctivitis, long-term usage of contact lenses, dermatological diseases that affect conjunctival homeostasis, Stevens-Johnson's syndrome or chemical burning of the ocular surface and lid margin.

Ocular Emergencies: Red Eye

"Red eye" is used as a general term to describe irritated or bloodshot eyes. It is a recognizable sign of an acute/chronic, localized/systemic underlying inflammatory condition. Conjunctival injection is most commonly caused by dryness, allergy, visual fatigue, contact lens overwear, and local infections. In some instances, red eye can represent a true ocular emergency that should be treated by an ophthalmologist. A comprehensive assessment of red eye conditions is required to preserve the patients visual function. Severe ocular pain, significant photophobia, decreased vision, and history of ocular trauma are warning signs demanding immediate ophthalmological consultation.

Effectiveness of heparin eye drops in paraquat-induced ocular injury

PURPOSE

To evaluate the efficacy of heparin eye drops in the treatment of paraquat-induced ocular surface injury.

DESIGN AND METHODS

In this retrospective study, we included 25 patients (31 eyes) with paraquat-induced ocular surface injury, who attended the Affiliated Hospital of Weifang Medical University between October 2008 and October 2013. The patients were split into two groups according to whether or not received heparin eye drops. The clinical data were compared between the two groups, i.e. clinical histories, results of examinations, treatments and outcomes.

RESULTS

Eleven patients (group A, 15 eyes) received prompt irrigation with 0.9% saline every two hours, 0.1% pranoprofen eye drops four times a day, 20% autologous serum every two hours, recombinant bovine basic fibroblast growth factor eye-gel two times a day, oral vitamin C 2.0 g and prednisone 30 mg daily. Fourteen patients (group B, 16 eyes) received additional treatment with heparin eye drops. Ten eyes in group A and seven eyes in group B developed a pseudomembrane on the ocular surface at significantly different rate (mean ± SD) of 1.20 ± 1.01 and 0.43 ± 0.51, respectively (t = 2.66, p = 0.01). Seven eyes among 10 had a pseudomembrane reoccurred in group A while none had a pseudomembrane reoccurred in group B (Fisher's exact test, p = 0.01). No significant differences were seen in the duration of epithelial recovery between the two groups: 15.13 ± 5.13 days in group A and 16.81 ± 5.56 days in group B (t = 0.87, p = 0.39). After the treatment, mild corneal opacity and pannus were observed in five patients of group A and four patients of group B, without any significant difference between the two groups (p = 0.70).

CONCLUSIONS

The paraquat-induced ocular surface injury observed in this case series was characterized by the formation of conjunctival pseudomembrane with good prognosis and mild complications. Heparin eye drops reduce the occurrence, especially the reoccurrence of pseudomembrane. Further studies are warranted.

Protective effects of batroxobin on a nigrostriatal pathway injury in mice

Traumatic brain injury triggers a series of damaged processes, such as neuronal death and apoptosis, inflammation and scar formation, which contribute to evolution of brain injury. The present study investigated the neuroprotective effects of batroxobin, a drug widely used clinically for ischemia, in a nigrostriatal pathway injury model. Mice subjected to the nigrostriatal pathway injury were injected with batroxobin (30 BU/kg) or vehicle immediately after injury. The behavioral studies showed that batroxobin could improve the motor function in injured mice in long term. Batroxobin also reduced neuronal apoptosis and inflammation at the acute stage. Moreover, administration of batroxobin attenuated the scar formation and reduced the lesion size at 4 and 14days after brain injury. These results suggest that batroxobin has beneficial effects on the nigrostriatal pathway injury, indicating a potential clinical application.

Nanoparticle-mediated expression of a Wnt pathway inhibitor ameliorates ocular neovascularization

OBJECTIVE

The deficiency of very low-density lipoprotein receptor resulted in Wnt signaling activation and neovascularization in the retina. The present study sought to determine whether the very low-density lipoprotein receptor extracellular domain (VLN) is responsible for the inhibition of Wnt signaling in ocular tissues.

APPROACH AND RESULTS

A plasmid expressing the soluble VLN was encapsulated with poly(lactide-co-glycolide acid) to form VLN nanoparticles (VLN-NP). Nanoparticles containing a plasmid expressing the low-density lipoprotein receptor extracellular domain nanoparticle were used as negative control. MTT, modified Boyden chamber, and Matrigel (™) assays were used to evaluate the inhibitory effect of VLN-NP on Wnt3a-stimulated endothelial cell proliferation, migration, and tube formation. Vldlr(-/-) mice, oxygen-induced retinopathy, and alkali burn-induced corneal neovascularization models were used to evaluate the effect of VLN-NP on ocular neovascularization. Wnt reporter mice (BAT-gal), Western blotting, and luciferase assay were used to evaluate Wnt pathway activity. Our results showed that VLN-NP specifically inhibited Wnt3a-induced endothelial cell proliferation, migration, and tube formation. Intravitreal injection of VLN-NP inhibited abnormal neovascularization in Vldlr(-/-), oxygen-induced retinopathy, and alkali burn-induced corneal neovascularization models, compared with low-density lipoprotein receptor extracellular domain nanoparticle. VLN-NP significantly inhibited the phosphorylation of low-density lipoprotein receptor-related protein 6, the accumulation of β-catenin, and the expression of vascular endothelial growth factor in vivo and in vitro.

CONCLUSIONS

Taken together, these results suggest that the soluble VLN is a negative regulator of the Wnt pathway and has antiangiogenic activities. Nanoparticle-mediated expression of VLN may thus represent a novel therapeutic approach to treat pathological ocular angiogenesis and potentially other vascular diseases affected by Wnt signaling.

Diffuse corneal abrasion after ocular exposure to laundry detergent pod

Although ocular injury from alkaline household cleaning products is well described, there is less known about the significance and extent of injury with ocular exposure to detergent pods. We report a 12-month-old with diffuse corneal abrasion caused by ocular contact with a laundry detergent pod. In addition to the known risks with aspiration with detergent pods, the potential for severe ocular injury is important for parents and clinicians to recognize. Children with ocular exposure to detergent pods should seek immediate medical care.