Jae Chan Kim

Background: Benzalkonium chloride (BAK), commonly used in glaucoma treatment, is an eye drop preservative with dose-dependent toxicity. Previous studies have observed the multi-functional benefits of angiogenin (ANG) against glaucoma. In our study, we evaluated ANG’s cytoprotective effect on the trabecular meshwork (TM) damage induced by BAK. Additionally, we developed a plant-derived ANG fusion protein and evaluated its effect on TM structure and function. Methods: We synthesized plant-derived ANG (ANG-FcK) by fuzing immunoglobulin G’s Fc region and KDEL to conventional recombinant human ANG (Rh-ANG) purified from transgenic tobacco plants. We established a mouse model using BAK to look for degenerative changes in the TM, and to evaluate the protective effects of ANG-FcK and Rh-ANG. Intraocular pressure (IOP) was measured for 4 weeks and ultrastructural changes, deposition of fluorescent microbeads, type I and IV collagen, fibronectin, laminin and α-SMA expression were analyzed after the mice were euthanized. Results: TM structural and functional degeneration were induced by 0.1% BAK instillation in mice. ANG co-treatment preserved TM outflow function, which we measured using IOP and a microbead tracer. ANG prevented phenotypic and ultrastructure changes, and that protective effect might be related to the anti-fibrosis mechanism. We observed a similar cytoprotective effect in the BAK-induced degenerative TM mouse model, suggesting that plant-derived ANG-FcK could be a promising glaucoma treatment.

Angiogenin (ANG) is involved in the innate immune system and inflammatory disease. The aim of this study is to evaluate the anti-inflammatory effects of ANG in an endotoxin induced uveitis (EIU) rat model and the pathways involved. EIU rats were treated with balanced salt solution (BSS), a non-functional mutant ANG (mANG), or wild-type ANG (ANG). The integrity of the blood-aqueous barrier was evaluated by the infiltrating cell and protein concentrations in aqueous humor. Histopathology, Western blot, and real-time qRT-PCR of aqueous humor and ocular tissue were performed to analyze inflammatory cytokines and transcription factors. EIU treated with ANG had decreased inflammatory cells and protein concentrations in the anterior chamber. Compared to BSS and mANG, ANG treatment showed reduced expression of IL-1β, IL-8, TNF-α, and Myd88, while the expression of IL-4 and IL-10 was increased. Western blot of ANG treatment showed decreased expression of IL-6, inducible nitric oxide synthase (iNOS), IL-1β, TNF-α, and phosphorylated NF-κB and increased expression of IL-10. In conclusion, ANG seems to reduce effectively immune mediated inflammation in the EIU rat model by reducing the expression of proinflammatory cytokines, while increasing the expression of anti-inflammatory cytokines through pathways related to NF-κB. Therefore, ANG shows potential for effectively suppressing immune-inflammatory responses in vivo.

Kim JH, et al. J Korean Ophthalmol Soc. 2019 May;60(5):414-420. https://doi.org/10.3341/jkos.2019.60.5.414

Park J, et al. J Korean Ophthalmol Soc. 2019 Jan;60(1):55-61. https://doi.org/10.3341/jkos.2019.60.1.55

To determine the effects of botulinum toxin type A (BTX-A) injection on dry eye signs, symptoms, and tear cytokine levels in patients with intractable dry eye disease (DED).

Human corneal endothelial cells (HCECs) are scarcely proliferative in vivo. The cultured HCECs engineered to overexpress ribonuclease (RNase) 5 (R5‐HCECs) are prepared after transient transfection with RNase 5 plasmid vector. As candidate targets of R5‐HCECs for enhancement of cellular proliferation and survival of R5‐HCECs, programmed cell death protein 4 is inhibited, and cyclin D1 and cyclin E1 are activated. The cultured R5‐HCECs and control HCECs on lyophilized amniotic membrane (AM) are deposited as a carrier by extrusion‐based 3D bioprinting to prepare transplantable RNase 5 vector‐transfected HCECs–laden AM graft (R5‐Graft) and the control HCECs–laden AM graft (Ct‐Graft), respectively. The ready‐to‐use R5‐Graft shows clearer basolateral expression of Na⁺‐K⁺ ATPase pump and higher cell confluency than Ct‐Graft. From 2 weeks after graft transplantation, both R5‐Graft and Ct‐Graft start restoring clarity of the rabbit corneas, and their central corneal edema are much less than those in the control group at 3 and 4 weeks. The ex vivo expression of corneal endothelial phenotypical markers is clear in R5‐Grafs rather than in Ct‐Grafts at 4 weeks. In conclusion, the fabricated corneal endothelium with cultured HCECs easily survives and functions as corneal endothelium in vivo. Furthermore, the use of the cultured HCECs engineered to overexpress RNase 5 (R5‐HCECs) may be an option to obtain higher graft cellularity and to enhance the function of transplanted grafts.

Pterygium, a common ocular surface disorder, has a complex pathophysiology that may mimic tumorigenesis. There is altered expression of cell cycle/proliferation-related factors in pterygium tissues. Therefore, similar to cancer treatments, the management of pterygium ought to be multifactorial based on the patient's condition. Current therapeutic methods for pterygium are focused on surgical resection in conjunction with antimetabolite use, in addition tissue graft is usually performed in the context of the avoidance of bare sclera. However, future directions in the management of pterygia will likely focus on genetic approaches. This perspective views the pathogenesis of pterygium, its existing therapies as well as current and future challenges in its treatment.

Purpose: The amniotic membrane (AM) is the transparent innermost layer of the placenta and it facilitates rapid wound healing in a diversity of ocular surface disorders. However, extended periods of cryopreservation before use induce significant impairment of cell viability due to oxidative stresses and inflammatory responses. We investigated the effect of supplementing ulinastatin (ULI), a known serine protease inhibitor, and relevant mechanisms of action in AM preservation solution through the hypothermic continuum on inflammatory and apoptotic signals and viability of AM tissue. Materials and methods: The expression of inflammatory signal factors, including high mobility group box 1 (HMGB1), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), receptor-interacting serine/threonine-protein kinase 3 (RIPK3) and anti-TNF-inducible gene 6 (TSG-6) which is a TNF-α-inducible anti-inflammatory protein, and the expression of apoptotic signal factors, including caspase (Cas)-9 and Cas-8, the initiators, and Cas-3, the executioner caspase and Bax were analyzed with or without ULI during hypothermic preservation of human AM. Subsequently, the actual viability of human AM tissue was verified with or without ULI supplementation throughout hypothermic continuum (both hypothermic- and cryopreservation). Results: Hypothermic AM preservation with ULI for 48 h resulted in downregulated expression of cold-inducible inflammatory factors, including HMGB1 and NF-κB, as well as RIPK3. In addition, ULI suppressed apoptotic signals related with Cas-9, Cas-8, and Cas-3 under hypothermic conditions. Furthermore, ULI supplementation during hypothermic- and cryopreservation of AM significantly enhanced viability of AM tissue and amniotic epithelial cells. Conclusions: Supplementation of ULI during human AM preservation through the hypothermic continuum may be a feasible dual anti-inflammatory and anti-apoptotic strategy that enhances the viability of AM tissue.