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Xeroudaki M, Rafat M, Moustardas P, Mukwaya A, Tabe S, Bellisario M, Peebo B, Lagali N. A double-crosslinked nanocellulose-reinforced dexamethasone-loaded collagen hydrogel for corneal application and sustained anti-inflammatory activity. Acta Biomater 2023; 172:234-248. [PMID: 37866722 DOI: 10.1016/j.actbio.2023.10.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 09/29/2023] [Accepted: 10/17/2023] [Indexed: 10/24/2023]
Abstract
In cases of blinding disease or trauma, hydrogels have been proposed as scaffolds for corneal regeneration and vehicles for ocular drug delivery. Restoration of corneal transparency, augmenting a thin cornea and postoperative drug delivery are particularly challenging in resource-limited regions where drug availability and patient compliance may be suboptimal. Here, we report a bioengineered hydrogel based on porcine skin collagen as an alternative to human donor corneal tissue for applications where long-term stability of the hydrogel is required. The hydrogel is reinforced with cellulose nanofibers extracted from the Ciona intestinalis sea invertebrate followed by double chemical and photochemical crosslinking. The hydrogel is additionally loaded with dexamethasone to provide sustained anti-inflammatory activity. The reinforced double-crosslinked hydrogel after drug loading maintained high optical transparency with significantly improved mechanical characteristics compared to non-reinforced hydrogels, while supporting a gradual sustained drug release for 60 days in vitro. Dexamethasone, after exposure to crosslinking and sterilization procedures used in hydrogel production, inhibited tube formation and cell migration of TNFα-stimulated vascular endothelial cells. The drug-loaded hydrogels suppressed key pro-inflammatory cytokines CCL2 and CXCL5 in TNFα-stimulated human corneal epithelial cells. Eight weeks after intra-stromal implantation in the cornea of 12 New-Zealand white rabbits subjected to an inflammatory suture stimulus, the dexamethasone-releasing hydrogels suppressed TNFα, MMP-9, and leukocyte and fibroblast cell invasion, resulting in reduced corneal haze, sustained corneal thickness and stromal morphology, and reduced overall vessel invasion. This collagen-nanocellulose double-crosslinked hydrogel can be implanted to treat corneal stromal disease while suppressing inflammation and maintaining transparency after corneal transplantation. STATEMENT OF SIGNIFICANCE: To treat blinding diseases, hydrogel scaffolds have been proposed to facilitate corneal restoration and ocular drug delivery. Here, we improve on a clinically tested collagen-based scaffold to improve mechanical robustness and enzymatic resistance by incorporating sustainably sourced nanocellulose and dual chemical-photochemical crosslinking to reinforce the scaffold, while simultaneously achieving sustained release of an incorporated anti-inflammatory drug, dexamethasone. Evaluated in the context of a corneal disease model with inflammation, the drug-releasing nanocellulose-reinforced collagen scaffold maintained the cornea's transparency and resisted degradation while suppressing inflammation postoperatively. This biomaterial could therefore potentially be applied in a wider range of sight-threatening diseases, overcoming suboptimal administration of postoperative medications to maintain hydrogel integrity and good vision.
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Affiliation(s)
- Maria Xeroudaki
- Division of Ophthalmology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Mehrdad Rafat
- NaturaLens AB, Linköping, Sweden; LinkoCare Life Sciences AB, Linköping, Sweden; Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Petros Moustardas
- Division of Ophthalmology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Anthony Mukwaya
- Division of Ophthalmology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Shideh Tabe
- NaturaLens AB, Linköping, Sweden; LinkoCare Life Sciences AB, Linköping, Sweden
| | - Marco Bellisario
- Division of Ophthalmology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Beatrice Peebo
- Division of Ophthalmology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden; Memira Eye Center Scandinavia, Solna, Sweden
| | - Neil Lagali
- Division of Ophthalmology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden; Department of Ophthalmology, Sørlandet Hospital Arendal, Arendal, Norway.
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Tavangarrad N, Mosleh N, Shomali T, Namazi F, Masoudian M. Evaluation of delaying effects of different short-term dosage regimens of topical ciprofloxacin on corneal ulcer healing in an avian model. Vet Med Sci 2023; 9:999-1007. [PMID: 36251730 PMCID: PMC10029881 DOI: 10.1002/vms3.972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Knowledge on possible delaying effects of topical ciprofloxacin on corneal ulcer healing is scarce in avian patients. OBJECTIVES The study evaluates effects of different dosage regimens of topical ciprofloxacin on healing of corneal ulcer in an avian model. METHODS One hundred and fifty adult layers were randomly allocated into two equal categories each consisted of 5 groups (n = 15): 1, negative control (NC, normal cornea); 2, positive control (PC) (birds with experimental corneal ulcer); and 3, 4 and 5, birds with corneal injury that received ciprofloxacin 0.3% topically q6h, q8h and q12h, respectively for 3 (category 1) or 5 days (category 2). Corneas were excised for histopathological evaluation and determination of MMP-9 expression. RESULTS While no significant difference was observed in daily-measured fluorescein-stained ulcer size among ciprofloxacin-treated birds and PC group in category 1, birds in PC group of category 2 had significantly smaller ulcers as compared to antibiotic-treated birds at the end of experiment (p < 0.01 for all cases). Histopathological evaluations at the end of the experiment showed no significant difference among PC and ciprofloxacin-treated birds of both categories for almost all of the assayed parameters. Over expression of MMP-9 mRNA was observed in PC group after 3 and 5 days of ulcer induction compared to NC groups. Its expression in ciprofloxacin-treated birds of both categories remained close to PC groups. CONCLUSIONS While ciprofloxacin administration for 3 days does not affect ulcer healing, it delays healing process at the end of 5 days of treatments in an avian model of corneal ulcer injury. This delaying effect is not associated with a drastic change in MMP-9 expression.
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Affiliation(s)
- Niloofar Tavangarrad
- Avian Diseases Research Center, Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - N Mosleh
- Avian Diseases Research Center, Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Tahoora Shomali
- Division of Pharmacology and Toxicology, Department of Basic Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Fatemeh Namazi
- Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Maliheh Masoudian
- Molecular Department of Central Laboratory, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
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Wei C, Song J, Tan H. A paintable ophthalmic adhesive with customizable properties based on symmetrical/asymmetrical cross-linking. Biomater Sci 2021; 9:7522-7533. [PMID: 34643623 DOI: 10.1039/d1bm01197a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In situ and efficient incision sealing for ophthalmic surgery remains unresolved. Current commercially available gel adhesives often suffer from unsuitable gelation time, difficulty in micro-delivery, and mismatched degradation period, leading to difficulties for application in ocular tissue areas. Herein, a novel hydrogel adhesive was developed based on the simultaneous crosslinking of poly(lysine) (PLL) and lysine (Lys) with an end-modified active ester multi-arm polyethylene glycol (PEG) via the amidation reaction, where the residual terminal active ester of PEG can also bond to amino groups on tissue to provide strong adhesion. Due to the different molecular structures around their amino groups, PLL and Lys can crosslink with 4-arm-PEG-NHS (active ester) respectively, to form symmetrical and asymmetrical crosslinking networks, which exhibit various mechanical properties. Therefore, just by adjusting PLL/Lys ratios, the PEG-PLL-Lys hydrogel can easily possess a suitable gelation time, appropriate mechanical properties and matched degradation rate. As a result, a paintable, readily accessible and biocompatible ophthalmic tissue adhesive (sealant) is prepared for sealing ocular tissue incision. Considering the simple strategy and outstanding performance, the PEG-PLL-Lys hydrogel is promising for clinical transformation.
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Affiliation(s)
- Changzheng Wei
- Shanghai Qisheng Biological Preparation Co., Ltd, Shanghai, 201106, China.
| | - Jialin Song
- Shanghai Qisheng Biological Preparation Co., Ltd, Shanghai, 201106, China.
| | - Haoqi Tan
- Shanghai Qisheng Biological Preparation Co., Ltd, Shanghai, 201106, China.
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4
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Soleimani M, Naderan M. Management Strategies of Ocular Chemical Burns: Current Perspectives. Clin Ophthalmol 2020; 14:2687-2699. [PMID: 32982161 PMCID: PMC7501954 DOI: 10.2147/opth.s235873] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 08/20/2020] [Indexed: 11/25/2022] Open
Abstract
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.
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Affiliation(s)
- Mohammad Soleimani
- Ocular Trauma and Emergency Department, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Morteza Naderan
- Ocular Trauma and Emergency Department, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
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5
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Bloch-Shilderman E, Yacov G, Cohen L, Egoz I, Gutman H, Gez R, Rabinovitz I, Nili U. Repetitive antidotal treatment is crucial in eliminating eye pathology, respiratory toxicity and death following whole-body VX vapor exposure in freely moving rats. Arch Toxicol 2019; 93:1365-1384. [DOI: 10.1007/s00204-019-02401-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 01/31/2019] [Indexed: 11/29/2022]
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Goswami DG, Kant R, Tewari-Singh N, Agarwal R. Efficacy of anti-inflammatory, antibiotic and pleiotropic agents in reversing nitrogen mustard-induced injury in ex vivo cultured rabbit cornea. Toxicol Lett 2018; 293:127-132. [PMID: 29174984 DOI: 10.1016/j.toxlet.2017.11.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 11/13/2017] [Accepted: 11/22/2017] [Indexed: 01/01/2023]
Abstract
Vesicating agent, Sulfur mustard (SM), causes devastating eye injury; however, there are no effective antidotes available. Using nitrogen mustard (NM), a bi-functional analog of SM, we have earlier reported that NM-induced corneal injury in ex vivo rabbit cornea organ culture model parallels corneal injury reported with SM. Using this model, we have demonstrated the therapeutic efficacy of dexamethasone (DEX), doxycycline (DOX) and silibinin (SB) in reversing NM (2h exposure)-induced corneal injuries when added immediately after washing NM. In the present study, we further examined the efficacy of similar/higher doses of these agents when added immediately, 2, or 4h after washing NM following its 2h exposure. All three treatment agents caused a reversal in established NM-induced injury biomarkers when added immediately or 2h after washing NM following its 2h exposure; however, when treatments were carried out 4h after washing NM, there was no significant effect. Together, our results further show the beneficial effect of these agents in reversing NM-induced corneal injury and indicate the time window for effective treatment. This could be useful towards future development of targeted therapeutics against vesicant-induced ocular injury.
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Affiliation(s)
- Dinesh G Goswami
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Rama Kant
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Neera Tewari-Singh
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Rajesh Agarwal
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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Treatment of acute ocular chemical burns. Surv Ophthalmol 2017; 63:214-235. [PMID: 28935121 DOI: 10.1016/j.survophthal.2017.09.005] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 01/15/2023]
Abstract
Ocular chemical burns are an ophthalmic emergency and are responsible for 11.5%-22.1% of ocular injuries. Immediate copious irrigation is universally recommended in acute ocular burns to remove the offending agent and minimize damage. Conventional medical therapy consists of the use of agents that promote epithelialization, minimize inflammation, and prevent cicatricial complications. Biological fluids such as autologous serum, umbilical cord blood serum, platelet-rich plasma, and amniotic membrane suspension are a rich source of growth factors and promote healing when used as adjuncts to conventional therapy. Surgical treatment of acute ocular burns includes the debridement of the necrotic tissue, application of tissue adhesives, tenoplasty, and tectonic keratoplasty. Amniotic membrane transplantation is a novel surgical treatment that is increasingly being used as an adjunct to conventional treatment to promote epithelial healing, minimize pain, and restore visual acuity. Various experimental treatments that aim to promote wound healing and minimize inflammation are being evaluated such as human mesenchymal and adipose stem cells, beta-1,3 glucan, angiotensin-converting enzyme inhibitors, cultivated fibroblasts, zinc desferrioxamine, antifibrinolytic agents, antioxidants, collagen cross-linking, and inhibitors of corneal neovascularization.
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Goswami DG, Tewari-Singh N, Agarwal R. Corneal toxicity induced by vesicating agents and effective treatment options. Ann N Y Acad Sci 2016; 1374:193-201. [PMID: 27327041 DOI: 10.1111/nyas.13121] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/04/2016] [Accepted: 05/10/2016] [Indexed: 12/20/2022]
Abstract
The vesicating agents sulfur mustard (SM) and lewisite (LEW) are potent chemical warfare agents that primarily cause damage to the ocular, skin, and respiratory systems. However, ocular tissue is the most sensitive organ, and vesicant exposure results in a biphasic injury response, including photophobia, corneal lesions, corneal edema, ulceration, and neovascularization, and may cause loss of vision. There are several reports on ocular injury from exposure to SM, which has been frequently used in warfare. However, there are very few reports on ocular injury by LEW, which indicate that injury symptoms appear instantly after exposure and faster than SM. In spite of extensive research efforts, effective therapies for vesicant-induced ocular injuries, mainly to the most affected corneal tissue, are not available. Hence, we have established primary human corneal epithelial cells and rabbit corneal organ culture models with the SM analog nitrogen mustard, which have helped to test the efficacy of potential therapeutic agents. These agents will then be further evaluated against in vivo SM- and LEW-induced corneal injury models, which will assist in the development of potential broad-spectrum therapies against vesicant-induced ocular injuries.
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Affiliation(s)
- Dinesh G Goswami
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Neera Tewari-Singh
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Rajesh Agarwal
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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Tewari-Singh N, Jain AK, Inturi S, Ammar DA, Agarwal C, Tyagi P, Kompella UB, Enzenauer RW, Petrash JM, Agarwal R. Silibinin, dexamethasone, and doxycycline as potential therapeutic agents for treating vesicant-inflicted ocular injuries. Toxicol Appl Pharmacol 2012; 264:23-31. [PMID: 22841772 DOI: 10.1016/j.taap.2012.07.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 07/09/2012] [Accepted: 07/10/2012] [Indexed: 02/07/2023]
Abstract
There are no effective and approved therapies against devastating ocular injuries caused by vesicating chemical agents sulfur mustard (SM) and nitrogen mustard (NM). Herein, studies were carried out in rabbit corneal cultures to establish relevant ocular injury biomarkers with NM for screening potential efficacious agents in laboratory settings. NM (100nmol) exposure of the corneas for 2h (cultured for 24h), showed increases in epithelial thickness, ulceration, apoptotic cell death, epithelial detachment microbullae formation, and the levels of VEGF, cyclooxygenase-2 (COX-2) and matrix metalloproteinase-9 (MMP-9). Employing these biomarkers, efficacy studies were performed with agent treatments 2h and every 4h thereafter, for 24h following NM exposure. Three agents were evaluated, including prescription drugs dexamethasone (0.1%; anti-inflammatory steroid) and doxycycline (100nmol; antibiotic and MMP inhibitor) that have been studied earlier for treating vesicant-induced eye injuries. We also examined silibinin (100μg), a non-toxic natural flavanone found to be effective in treating SM analog-induced skin injuries in our earlier studies. Treatments of doxycycline+dexamethasone, and silibinin were more effective than doxycycline or dexamethasone alone in reversing NM-induced epithelial thickening, microbullae formation, apoptotic cell death, and MMP-9 elevation. However, dexamethasone and silibinin alone were more effective in reversing NM-induced VEGF levels. Doxycycline, dexamethasone and silibinin were all effective in reversing NM-induced COX-2 levels. Apart from therapeutic efficacy of doxycycline and dexamethasone, these results show strong multifunctional efficacy of silibinin in reversing NM-induced ocular injuries, which could help develop effective and safe therapeutics against ocular injuries by vesicants.
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Affiliation(s)
- Neera Tewari-Singh
- Department of Pharmaceutical Sciences, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO 80045, USA.
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Hormonal regulation of Na+/K+-dependent ATPase activity and pump function in corneal endothelial cells. Cornea 2012; 30 Suppl 1:S60-6. [PMID: 21912233 DOI: 10.1097/ico.0b013e318227faab] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Na- and K-dependent ATPase (Na,K-ATPase) in the basolateral membrane of corneal endothelial cells plays an important role in the pump function of the corneal endothelium. We investigated the role of dexamethasone in the regulation of Na,K-ATPase activity and pump function in these cells. Mouse corneal endothelial cells were exposed to dexamethasone or insulin. ATPase activity was evaluated by spectrophotometric measurement, and pump function was measured using an Ussing chamber. Western blotting and immunocytochemistry were performed to measure the expression of the Na,K-ATPase α1-subunit. Dexamethasone increased Na,K-ATPase activity and the pump function of endothelial cells. Western blot analysis indicated that dexamethasone increased the expression of the Na,K-ATPase α1-subunit but decreased the ratio of active to inactive Na,K-ATPase α1-subunit. Insulin increased Na,K-ATPase activity and pump function of cultured corneal endothelial cells. These effects were transient and blocked by protein kinase C inhibitors and inhibitors of protein phosphatases 1 (PP1) and 2A (PP2A). Western blot analysis indicated that insulin decreased the amount of inactive Na,K-ATPase α1-subunit, but the expression of total Na,K-ATPase α1-subunit was unchanged. Immunocytochemistry showed that insulin increased cell surface expression of the Na,K-ATPase α1-subunit. Our results suggest that dexamethasone and insulin stimulate Na,K-ATPase activity in mouse corneal endothelial cells. The effect of dexamethasone activation in these cells was mediated by Na,K-ATPase synthesis and an increased enzymatic activity because of dephosphorylation of Na,K-ATPase α1-subunits. The effect of insulin is mediated by the protein kinase C, PP1, and/or PP2A pathways.
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Chen WL, Lin CT, Yao CC, Huang YH, Chou YB, Yin HS, Hu FR. In-Vitro Effects of Dexamethasone on Cellular Proliferation, Apoptosis, and Na+-K+-ATPase Activity of Bovine Corneal Endothelial Cells. Ocul Immunol Inflamm 2009; 14:215-23. [PMID: 16911983 DOI: 10.1080/09273940600732380] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To assess the in-vitro effects of dexamethasone (DEX) on the proliferation, apoptosis, and Na+-K+-ATPase activity of bovine corneal endothelial cells. METHODS Bovine corneal endothelial cells were cultured with DEX ranging from 10-10 to 10-3 M. The effect of DEX on the proliferation was analyzed by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxy-methoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS) assay. Apoptosis and necrosis were detected by staining with fluorescein-conjugated annexin V and propidium iodide, followed by flow cytometry. The effect of DEX on Na+-K+-ATPase activity was evaluated using non-isotopic methods. RESULTS DEX did not affect cellular proliferation or induce apoptosis/necrosis from 10-10 to 10-5 M. At 10-4 and 10-3 M, DEX significantly decreased proliferation and increased apoptosis and/or necrosis. DEX significantly increased the Na+-K+-ATPase activity from 10-8 to 10-6 M, with the maximal effect at 10-6 M (p < 0.01); this effect was inhibited by RU38486, an antiglucocorticoid molecule. CONCLUSIONS Bovine corneal endothelial cells express glucocorticoid receptor (GR) mRNA and protein. DEX decreases cell proliferation and induces cellular apoptosis and/or necrosis at high concentrations. DEX also increases the Na+-K+-ATPase activity at certain concentrations.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Blotting, Western
- Cattle
- Cell Proliferation/drug effects
- Cells, Cultured
- Dexamethasone/pharmacology
- Electrophoresis, Polyacrylamide Gel
- Endothelium, Corneal/drug effects
- Endothelium, Corneal/metabolism
- Endothelium, Corneal/pathology
- Flow Cytometry
- Fluorescent Antibody Technique, Indirect
- Glucocorticoids/pharmacology
- Hormone Antagonists/pharmacology
- Microscopy, Fluorescence
- Mifepristone/pharmacology
- RNA, Messenger/metabolism
- Receptors, Glucocorticoid/genetics
- Receptors, Glucocorticoid/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sodium-Potassium-Exchanging ATPase/metabolism
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Affiliation(s)
- Wei-Li Chen
- Department of Ophthalmology and Graduate Institute of Clinical Medicine, National Taipei University Hospital, Taipei, Taiwan
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12
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Hatou S, Yamada M, Mochizuki H, Shiraishi A, Joko T, Nishida T. The effects of dexamethasone on the Na,K-ATPase activity and pump function of corneal endothelial cells. Curr Eye Res 2009; 34:347-54. [PMID: 19401877 DOI: 10.1080/02713680902829624] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE The Na(+)- and K(+)-dependent ATPase (Na,K-ATPase) expressed in the basolateral membrane of corneal endothelial cells plays an important role in the pump function of the corneal endothelium. We investigated the possible role of dexamethasone in the regulation of Na,K-ATPase activity and pump function in corneal endothelial cells. METHODS Confluent monolayers of mouse corneal endothelial cells were exposed to dexamethasone. ATPase activity of the cells was evaluated by spectrophotometric measurement of phosphate released from ATP with the use of ammonium molybdate, with Na,K-ATPase activity being defined as the portion of total ATPase activity sensitive to ouabain. Pump function of the cells was measured with the use of an Ussing chamber, with the pump function attributable to Na,K-ATPase activity being defined as the portion of the total short-circuit current sensitive to ouabain. Western blot analysis was examined to measure the expression of the Na,K-ATPase alpha(1)-subunit. RESULTS Dexamethasone (1 or 10 microM) increased the Na,K-ATPase activity and pump function of the cultured cells. These effects of dexamethasone were blocked by cycloheximide, a protein synthesis inhibitor. Western blot analysis also indicated that dexamethasone increased the expression of the Na,K-ATPase alpha(1)-subunit, whereas it decreased the expression of the phospho-Na,K-ATPase alpha(1)-subunit. CONCLUSIONS Our results suggest that dexamethasone stimulates Na,K-ATPase activity in mouse corneal endothelial cells. The effect of dexamethasone activation in these cells is mediated by Na,K-ATPase synthesis and increase in an enzymatic activity by dephosphorylation of Na,K-ATPase alpha(1)-subunits.
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Affiliation(s)
- Shin Hatou
- Division for Vision Research, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
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Abstract
Corticosteroids, used prudently, are one of the most potent and effective modalities available in the treatment of ocular inflammation. However, they can produce a plethora of adverse ocular and systemic events. In order to optimise and target drug delivery, whilst minimising systemic adverse effects, a diverse range of local ophthalmic preparations and delivery techniques have been developed. Topical drops and ointments remain the primary methods for administration of ocular corticosteroids. However, ocular penetration of topical corticosteroid drops depends upon drug concentration, chemical formulation of corticosteroid, and composition of the vehicle, therefore, apparently small modifications in preparations can produce a more than 20-fold difference in intraocular drug concentration. Periocular injections of corticosteroids continue to have a useful, but limited, therapeutic role and longer acting, intraocular delayed-release devices are in early clinical studies. Although newer corticosteroids with lesser pressure elevating characteristics have been developed, corticosteroid-induced ocular hypertension and glaucoma continue to be significant risks of local and systemic administration. Posterior subcapsular cataract, observed following as little as 4 months topical corticosteroids use, is thought to be due to covalent binding of corticosteroid to lens protein with subsequent oxidation. Inappropriate use of topical corticosteroid in the presence of corneal infections also continues to be a cause of ocular morbidity. Other risks of locally administered ophthalmic corticosteroids include: tear-film instability, epithelial toxicity, crystalline keratopathy, decreased wound strength, orbital fat atrophy, ptosis, limitation of ocular movement, inadvertent intraocular injection, and reduction in endogenous cortisol. This extensive review assesses the therapeutic benefits of locally administered ocular corticosteroids in the context of the risks of adverse effects.
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Affiliation(s)
- Charles N J McGhee
- Discipline of Ophthalmology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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