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Bonneau N, Potey A, Blond F, Guerin C, Baudouin C, Peyrin JM, Brignole-Baudouin F, Réaux-Le Goazigo A. Assessment of corneal nerve regeneration after axotomy in a compartmentalized microfluidic chip model with automated 3D high resolution live-imaging. Front Cell Neurosci 2024; 18:1417653. [PMID: 39076204 PMCID: PMC11285198 DOI: 10.3389/fncel.2024.1417653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 06/26/2024] [Indexed: 07/31/2024] Open
Abstract
Introduction Damage to the corneal nerves can result in discomfort and chronic pain, profoundly impacting the quality of life of patients. Development of novel in vitro method is crucial to better understand corneal nerve regeneration and to find new treatments for the patients. Existing in vitro models often overlook the physiology of primary sensory neurons, for which the soma is separated from the nerve endings. Methods To overcome this limitation, our novel model combines a compartmentalized microfluidic culture of trigeminal ganglion neurons from adult mice with live-imaging and automated 3D image analysis offering robust way to assess axonal regrowth after axotomy. Results Physical axotomy performed by a two-second aspiration led to a reproducible 70% axonal loss and altered the phenotype of the neurons, increasing the number of substance P-positive neurons 72 h post-axotomy. To validate our new model, we investigated axonal regeneration after exposure to pharmacological compounds. We selected various targets known to enhance or inhibit axonal regrowth and analyzed their basal expression in trigeminal ganglion cells by scRNAseq. NGF/GDNF, insulin, and Dooku-1 (Piezo1 antagonist) enhanced regrowth by 81, 74 and 157%, respectively, while Yoda-1 (Piezo1 agonist) had no effect. Furthermore, SARM1-IN-2 (Sarm1 inhibitor) inhibited axonal regrowth, leading to only 6% regrowth after 72 h of exposure (versus 34% regrowth without any compound). Discussion Combining compartmentalized trigeminal neuronal culture with advanced imaging and analysis allowed a thorough evaluation of the extent of the axotomy and subsequent axonal regrowth. This innovative approach holds great promise for advancing our understanding of corneal nerve injuries and regeneration and ultimately improving the quality of life for patients suffering from sensory abnormalities, and related conditions.
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Affiliation(s)
- Noémie Bonneau
- Sorbonne Université, INSERM, CNRS, IHU FOReSIGHT, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, IHU FOReSIGHT, Paris, France
| | - Anaïs Potey
- Sorbonne Université, INSERM, CNRS, IHU FOReSIGHT, Institut de la Vision, Paris, France
| | - Frédéric Blond
- Sorbonne Université, INSERM, CNRS, IHU FOReSIGHT, Institut de la Vision, Paris, France
| | - Camille Guerin
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, IHU FOReSIGHT, Paris, France
| | - Christophe Baudouin
- Sorbonne Université, INSERM, CNRS, IHU FOReSIGHT, Institut de la Vision, Paris, France
- Inserm-DGOS CIC 1423, IHU Foresight, Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Paris, France
- Hôpital Ambroise Paré, APHP, Université Versailles-Saint-Quentin-en-Yvelines, Boulogne-Billancourt, France
| | - Jean-Michel Peyrin
- UMR8246, Inserm U1130, IBPS, UPMC, Neurosciences Paris Seine, Sorbonne Université, Paris, France
| | - Françoise Brignole-Baudouin
- Sorbonne Université, INSERM, CNRS, IHU FOReSIGHT, Institut de la Vision, Paris, France
- Inserm-DGOS CIC 1423, IHU Foresight, Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Paris, France
- Faculté de Pharmacie de Paris, Université Paris Cité, Paris, France
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Chow BJ, Lee IXY, Liu C, Liu YC. Potential therapeutic effects of peroxisome proliferator-activated receptors on corneal diseases. Exp Biol Med (Maywood) 2024; 249:10142. [PMID: 38993197 PMCID: PMC11238193 DOI: 10.3389/ebm.2024.10142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 06/12/2024] [Indexed: 07/13/2024] Open
Abstract
The cornea is an avascular tissue in the eye that has multiple functions in the eye to maintain clear vision which can significantly impair one's vision when subjected to damage. Peroxisome proliferator-activated receptors (PPARs), a family of nuclear receptor proteins comprising three different peroxisome proliferator-activated receptor (PPAR) isoforms, namely, PPAR alpha (α), PPAR gamma (γ), and PPAR delta (δ), have emerged as potential therapeutic targets for treating corneal diseases. In this review, we summarised the current literature on the therapeutic effects of PPAR agents on corneal diseases. We discussed the role of PPARs in the modulation of corneal wound healing, suppression of corneal inflammation, neovascularisation, fibrosis, stimulation of corneal nerve regeneration, and amelioration of dry eye by inhibiting oxidative stress within the cornea. We also discussed the underlying mechanisms of these therapeutic effects. Future clinical trials are warranted to further attest to the clinical therapeutic efficacy.
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Affiliation(s)
- Bing Jie Chow
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Isabelle Xin Yu Lee
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore, Singapore
| | - Chang Liu
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore, Singapore
| | - Yu-Chi Liu
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore, Singapore
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-National University of Singapore (NUS) Medical School, Singapore, Singapore
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Mansoor H, Lee IXY, Lin MTY, Ang HP, Xue YC, Krishaa L, Patil M, Koh SK, Tan HC, Zhou L, Liu YC. Topical and oral peroxisome proliferator-activated receptor-α agonist ameliorates diabetic corneal neuropathy. Sci Rep 2024; 14:13435. [PMID: 38862650 PMCID: PMC11167005 DOI: 10.1038/s41598-024-64451-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 06/10/2024] [Indexed: 06/13/2024] Open
Abstract
Diabetic corneal neuropathy (DCN) is a common diabetic ocular complication with limited treatment options. In this study, we investigated the effects of topical and oral fenofibrate, a peroxisome proliferator-activated receptor-α agonist, on the amelioration of DCN using diabetic mice (n = 120). Ocular surface assessments, corneal nerve and cell imaging analysis, tear proteomics and its associated biological pathways, immuno-histochemistry and western blot on PPARα expression, were studied before and 12 weeks after treatment. At 12 weeks, PPARα expression markedly restored after topical and oral fenofibrate. Topical fenofibrate significantly improved corneal nerve fibre density (CNFD) and tortuosity coefficient. Likewise, oral fenofibrate significantly improved CNFD. Both topical and oral forms significantly improved corneal sensitivity. Additionally, topical and oral fenofibrate significantly alleviated diabetic keratopathy, with fenofibrate eye drops demonstrating earlier therapeutic effects. Both topical and oral fenofibrate significantly increased corneal β-III tubulin expression. Topical fenofibrate reduced neuroinflammation by significantly increasing the levels of nerve growth factor and substance P. It also significantly increased β-III-tubulin and reduced CDC42 mRNA expression in trigeminal ganglions. Proteomic analysis showed that neurotrophin signalling and anti-inflammation reactions were significantly up-regulated after fenofibrate treatment, whether applied topically or orally. This study concluded that both topical and oral fenofibrate ameliorate DCN, while topical fenofibrate significantly reduces neuroinflammation.
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Affiliation(s)
| | - Isabelle Xin Yu Lee
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Molly Tzu-Yu Lin
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Heng Pei Ang
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Yao Cong Xue
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - L Krishaa
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Moushmi Patil
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Siew-Kwan Koh
- Ocular Proteomic Group, Singapore Eye Research Institute, Singapore, Singapore
| | - Hong Chang Tan
- Department of Endocrinology, Singapore General Hospital, Singapore, Singapore
| | - Lei Zhou
- Department of Applied Biology and Chemical Technology, School of Optometry, Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hung Hom, Hong Kong
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Pak Shek Kok, Hong Kong
| | - Yu-Chi Liu
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, 11 Third Hospital Ave, Singapore, 168751, Singapore.
- Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore, Singapore.
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore, Singapore.
- Eye-Academic Clinical Program, Singapore Graduate Medical School, Duke-National University, Singapore, Singapore.
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan.
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Anam A, Liu C, Tong L, Liu YC. Blood-Derived Eye Drops for the Treatment of Corneal Neuropathic Pain. J Ocul Pharmacol Ther 2024; 40:281-292. [PMID: 38648544 PMCID: PMC11296151 DOI: 10.1089/jop.2023.0155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 03/18/2024] [Indexed: 04/25/2024] Open
Abstract
Blood-derived preparations, including autologous or allogenic serum, umbilical cord serum/plasma, and platelet-rich plasma eye drops, contain various growth factors, cytokines, and immunoglobulins that resemble natural tears. These components play important roles in corneal cell migration, proliferation, and wound healing. Blood-derived eye drops have demonstrated clinical effectiveness across a spectrum of ocular surface conditions, encompassing dry eye disease, Sjögren's syndrome, graft-versus-host disease, and neuropathic corneal pain (NCP). Currently, management of NCP remains challenging. The emergence of blood-derived eye drops represents a promising therapeutic approach. In this review, we discuss the benefits and limitations of different blood-derived eye drops, their mechanisms of action, and treatment efficacy in patients with NCP. Several studies have demonstrated the clinical efficacy of autologous serum eye drops in relieving pain and pain-like symptoms, such as allodynia and photoallodynia. Corneal nerve parameters were also significantly improved, as evidenced by increased nerve fiber density, length, nerve reflectivity, and tortuosity, as well as a decreased occurrence of beading and neuromas after the treatment. The extent of nerve regeneration correlated with improvement in patient-reported photoallodynia. Cord plasma eye drops also show potential for symptom alleviation and corneal nerve regeneration. Future directions for clinical practice and research involve standardizing preparation protocols, establishing treatment guidelines, elucidating underlying mechanisms, conducting long-term clinical trials, and implementing cost-effective measures such as scaling up manufacturing. With ongoing advancements, blood-derived eye drops hold promise as a valuable therapeutic option for patients suffering from NCP.
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Affiliation(s)
- Ansa Anam
- Department of Ophthalmology, MTI Khyber Teaching Hospital, Peshawar, Pakistan
| | - Chang Liu
- Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore, Singapore
| | - Louis Tong
- Department of Corneal and External Eye Disease, Singapore National Eye Centre, Singapore, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
- Ocular Surface Group, Singapore Eye Research Institute, Singapore, Singapore
| | - Yu-Chi Liu
- Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore, Singapore
- Department of Corneal and External Eye Disease, Singapore National Eye Centre, Singapore, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
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Alrashidi SH. Effect of mitomycin C on the corneal endothelial cells of Saudi patients with myopia after transepithelial photorefractive keratectomy: a two-armed cohort study. Int J Ophthalmol 2024; 17:909-915. [PMID: 38766343 PMCID: PMC11074205 DOI: 10.18240/ijo.2024.05.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 02/04/2024] [Indexed: 05/22/2024] Open
Abstract
AIM To study the effect of mitomycin C (MMC) applied during transepithelial photorefractive keratectomy (TPRK) on the corneal endothelium one week (W1) and three months (M3) after surgery and its determinants. METHODS In this two-armed cohort study conducted in 2022, eyes treated with MMC during TPRK (group 1) were compared with eyes not treated with MMC (group 2). The corneal endothelial cell (EC) count, EC density (ECD; cells/mm2), average (µm2), standard deviation (µm2), coefficient of variation (CV%), ECmax, ECmin, and EC percentage of hexagonality were estimated at W1 and M3. The postoperative changes in the EC count in the two groups were compared and correlated with the other independent variables. RESULTS Group 1 had 26 eyes, and group 2 had 78 eyes. All TPRK indices were significantly higher for the eyes in group 1 than for those in group 2. The MMC usage was not a significant predictor of the change in ECD (P=0.644), change in CV (P=0.374), and change in the percentage of hexagonality of EC (P=0.164) at W1. However, the use of MMC was a significant predictor of changes in CV (P=0.014) and the change in the percentage of hexagonality of EC (P=0.039) at M3. The duration of laser exposure and the size of the optical zone influenced the correlation of MMC use with the changes in EC indices, postoperatively. CONCLUSION The use of MMC doesn't affect ECD, CV, and percentage of hexagonality at W1 if other surgical indices are considered. At M3 after operating myopic eyes by TPRK, MMC significantly influence the CV and percentage of hexagonality. The duration of the laser application and the size of the optical zone should be considered when determining the effect of MMC on the EC indices.
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Affiliation(s)
- Sultan H Alrashidi
- Department of Ophthalmology, College of Medicine, Qassim University, Buraidah 51452, Saudi Arabia
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Dossari SK. Post-refractive Surgery Dry Eye: A Systematic Review Exploring Pathophysiology, Risk Factors, and Novel Management Strategies. Cureus 2024; 16:e61004. [PMID: 38916023 PMCID: PMC11194137 DOI: 10.7759/cureus.61004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2024] [Indexed: 06/26/2024] Open
Abstract
Dry eye disease frequently manifests following corneal refractive procedures, significantly impacting patients' quality of life. This review systematically synthesizes current evidence on the pathophysiological mechanisms, risk factors, and therapeutic interventions for post-refractive surgery dry eye. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, a systematic review of literature published until August 2023 was conducted, focusing on post-refractive surgery dry eye. Eighteen relevant studies were identified through screening and eligibility assessment. A qualitative synthesis of outcomes was performed using narrative and thematic analysis methods. Surgically induced neurotrophic deficiency, stemming from nerve transection, triggers a cascade of events including apoptosis, inflammation, and lacrimal dysfunction, ultimately leading to tear film instability. Risk factors such as female gender, thyroid eye disease, meibomian gland dysfunction, higher ablation depths, and the use of LASIK over surface ablation exacerbate the condition. While conventional treatments like artificial tears provide temporary relief, emerging interventions such as nerve growth factors, matrix metalloproteinase inhibitors, serum eye drops, and specialized contact lenses show promise in promoting nerve regeneration and epithelial healing. Strategies such as customized ablation profiles, smaller optical zones, and nerve-sparing techniques like small incision lenticule extraction demonstrate potential advantages. A multifaceted therapeutic approach targeting neuroprotection, anti-inflammatory mechanisms, and tear film stabilization is imperative for effectively managing post-refractive surgery dry eye. Future research should focus on evaluating prognostic biomarkers, exploring precision medicine approaches, and investigating neuroprotective adjuvants to further enhance treatment outcomes.
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Affiliation(s)
- Saif K Dossari
- Department of Surgery, King Faisal University, Al-Hofuf, SAU
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Gong Q, Huang K, Li K, Tong Y, Zhao J, Wang H, Xu Z, Lin M, Lu F, Hu L. Structural and functional changes of binocular corneal innervation and ocular surface function after unilateral SMILE and tPRK. Br J Ophthalmol 2024:bjo-2023-324358. [PMID: 38527771 DOI: 10.1136/bjo-2023-324358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 02/18/2024] [Indexed: 03/27/2024]
Abstract
AIMS To evaluate the bilateral changes in the sub-basal nerve plexus of the cornea and ocular surface function after unilateral small incision lenticule extraction (SMILE) and transepithelial photorefractive keratectomy (tPRK) procedures. METHODS 34 patients were enrolled in the study and underwent unilateral SMILE (21 of 34 patients) or unilateral tPRK (13 of 34 patients). Complete ophthalmic examinations, tear film function tests and Cochet-Bonnet esthesiometry were conducted to assess the effects of the surgeries on the corneal nerves and tear function. Morphological changes were assessed using in vivo confocal microscopy to evaluate the corneal sub-basal nerve plexus and dendritic cells. ELISA was used to measure the tear neuromediators. Clinical and morphological data at each follow-up point were compared with preoperative baseline values. RESULTS All patients who underwent unilateral SMILE or tPRK procedures exhibited bilateral corneal nerve degenerative changes, decreased corneal sensitivity, worsening of dry eye symptoms and changes in bilateral tear neuromediators. In the SMILE group, bilateral corneal sensitivity was positively correlated with corneal nerve fibre length and negatively correlated with dendritic cell area. The dry eye severity was negatively correlated with corneal sensitivity. Tear levels of substance P and nerve growth factor were positively correlated with mean dendritic cell area and dry eye severity, but negatively correlated with corneal sensitivity. In the tPRK group, bilateral corneal sensitivity was positively correlated with corneal nerve fibre density. CONCLUSIONS Unilateral refractive surgery may bilaterally affect the morphology and function of corneal nerves and ocular surface status postoperatively.
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Affiliation(s)
- Qianwen Gong
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Kaiyan Huang
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Kexin Li
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yixuan Tong
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jian Zhao
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Hui Wang
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhiqiang Xu
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Meng Lin
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Fan Lu
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Liang Hu
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
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Chin JY, Liu C, Lee IXY, Lin MTY, Cheng CY, Wong JHF, Teo CL, Mehta JS, Liu YC. Impact of Age on the Characteristics of Corneal Nerves and Corneal Epithelial Cells in Healthy Adults. Cornea 2024; 43:409-418. [PMID: 37643477 PMCID: PMC10906190 DOI: 10.1097/ico.0000000000003363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/26/2023] [Accepted: 07/02/2023] [Indexed: 08/31/2023]
Abstract
PURPOSE The aim of this study was to investigate age-related changes in corneal nerves and corneal epithelial cell parameters and to establish age-adjusted reference values. METHODS A total of 7025 corneal nerve images and 4215 corneal epithelial images obtained using in vivo confocal microscopy from 281 eyes of 143 healthy participants were included. Seven corneal nerve parameters and 3 corneal epithelial cell parameters were quantified using 2 automatic analytic software and analyzed across 6 age groups ranging from 21 to 80 years. RESULTS There was a declining trend in all 7 nerve parameters with advancing age. In particular, corneal nerve fiber length and corneal nerve fiber density demonstrated a significant decrease in subjects aged 65 years or older compared with subjects younger than 65 years (10.8 ± 2.6 mm/mm 2 vs. 9.9 ± 2.0 mm/mm 2 , P = 0.011 in corneal nerve fiber length; 15.8 ± 5.2 fibers/mm 2 vs. 14.4 ± 4.3 fibers/mm 2 , P = 0.046 in corneal nerve fiber density), whereas corneal nerve fractal dimension demonstrated a borderline significant decrease ( P = 0.057). Similarly, there was a general declining trend in all epithelial cell parameters with advancing age. Corneal epithelial cell circularity was significantly lower in subjects aged 65 years and older as compared to subjects younger than 65 years (0.722 ± 0.021 μm 2 vs. 0.714 ± 0.021 μm 2 ; P = 0.011). CONCLUSIONS Advancing age results in reduced corneal nerve metrics and alteration of corneal cell morphology. Aging effects should be considered when evaluating patients with corneal neuropathy.
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Affiliation(s)
- Jia Ying Chin
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore
| | - Chang Liu
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore
| | - Isabelle Xin Yu Lee
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore
| | - Molly Tzu Yu Lin
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore
| | - Ching-Yu Cheng
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
- Epidemiology Group, Singapore Eye Research Institute, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore, Singapore
| | - Jipson Hon Fai Wong
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore
| | - Cong Ling Teo
- Epidemiology Group, Singapore Eye Research Institute, Singapore
| | - Jodhbir S. Mehta
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore; and
| | - Yu-Chi Liu
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore; and
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
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Liu C, Lin MTY, Lee IXY, Wong JHF, Lu D, Lam TC, Zhou L, Mehta JS, Ong HS, Ang M, Tong L, Liu YC. Neuropathic Corneal Pain: Tear Proteomic and Neuromediator Profiles, Imaging Features, and Clinical Manifestations. Am J Ophthalmol 2024; 265:6-20. [PMID: 38521157 DOI: 10.1016/j.ajo.2024.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 01/05/2024] [Accepted: 03/15/2024] [Indexed: 03/25/2024]
Abstract
PURPOSE To investigate the tear proteomic and neuromediator profiles, in vivo confocal microscopy (IVCM) imaging features, and clinical manifestations in neuropathic corneal pain (NCP) patients. DESIGN Cross-sectional study. METHODS A total of 20 NCP patients and 20 age-matched controls were recruited. All subjects were evaluated by corneal sensitivity, Schirmer test, tear break-up time, and corneal and ocular surface staining, Ocular Surface Disease Index and Ocular Pain Assessment Survey questionnaires were administered, as well as IVCM examinations for corneal nerves, microneruomas, and epithelial and dendritic cells. Tears were collected for neuromediator and proteomic analysis using enzyme-linked immunosorbent assay and data-independent acquisition mass spectrometry. RESULTS Burning and sensitivity to light were the 2 most common symptoms in NCP. A total of 188 significantly dysregulated proteins, such as elevated metallothionein-2, creatine kinases B-type, vesicle-associated membrane protein 2, neurofilament light polypeptide, and myelin basic protein, were identified in the NCP patients. The top 10 dysregulated biological pathways in NCP include neurotoxicity, axonal signaling, wound healing, neutrophil degradation, apoptosis, thrombin signaling mitochondrial dysfunction, and RHOGDI and P70S6K signaling pathways. Compared to controls, the NCP cohort presented with significantly decreased corneal sensitivity (P < .001), decreased corneal nerve fiber length (P = .003), corneal nerve fiber density (P = .006), and nerve fiber fractal dimension (P = .033), as well as increased corneal nerve fiber width (P = .002), increased length, total area and perimeter of microneuromas (P < .001, P < .001, P = .019), smaller corneal epithelial size (P = .017), and higher nerve growth factor level in tears (P = .006). CONCLUSIONS These clinical manifestations, imaging features, and molecular characterizations would contribute to the diagnostics and potential therapeutic targets for NCP.
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Affiliation(s)
- Chang Liu
- From Tissue Engineering and Cell Therapy Group (C.L., M.T.-Y.L., I.X.Y.L., J.S.M., H.S.O., Y.-C.L.), Singapore Eye Research Institute, Singapore; Cornea and Refractive Surgery Group (C.L., J.S.M., H.S.O., Y.-C.L.), Singapore Eye Research Institute, Singapore
| | - Molly Tzu-Yu Lin
- From Tissue Engineering and Cell Therapy Group (C.L., M.T.-Y.L., I.X.Y.L., J.S.M., H.S.O., Y.-C.L.), Singapore Eye Research Institute, Singapore
| | - Isabelle Xin Yu Lee
- From Tissue Engineering and Cell Therapy Group (C.L., M.T.-Y.L., I.X.Y.L., J.S.M., H.S.O., Y.-C.L.), Singapore Eye Research Institute, Singapore
| | - Jipson Hon Fai Wong
- Clinical Research Platform (J.H.F.W.), Singapore Eye Research Institute, Singapore
| | - Daqian Lu
- Centre for Myopia Research (D.L., T.C.L.), School of Optometry, Hong Kong Polytechnic University, Hong Kong
| | - Thomas Chuen Lam
- Centre for Myopia Research (D.L., T.C.L.), School of Optometry, Hong Kong Polytechnic University, Hong Kong; Centre for Eye and Vision Research (CEVR) (T.C.L.), Hong Kong
| | - Lei Zhou
- School of Optometry (L.Z.), Department of Applied Biology and Chemical Technology, Research Centre for SHARP Vision (RCSV); The Hong Kong Polytechnic University, Hong Kong
| | - Jodhbir S Mehta
- From Tissue Engineering and Cell Therapy Group (C.L., M.T.-Y.L., I.X.Y.L., J.S.M., H.S.O., Y.-C.L.), Singapore Eye Research Institute, Singapore; Cornea and Refractive Surgery Group (C.L., J.S.M., H.S.O., Y.-C.L.), Singapore Eye Research Institute, Singapore; Department of Cornea and External Eye Disease (J.S.M., H.S.O., M.A., L.T., Y.-C.L.), Singapore National Eye Centre, Singapore; Ophthalmology and Visual Sciences Academic Clinical Program (J.S.M., H.S.O., M.A., Y.-C.L.), Duke-NUS Medical School, Singapore
| | - Hon Shing Ong
- From Tissue Engineering and Cell Therapy Group (C.L., M.T.-Y.L., I.X.Y.L., J.S.M., H.S.O., Y.-C.L.), Singapore Eye Research Institute, Singapore; Cornea and Refractive Surgery Group (C.L., J.S.M., H.S.O., Y.-C.L.), Singapore Eye Research Institute, Singapore; Department of Cornea and External Eye Disease (J.S.M., H.S.O., M.A., L.T., Y.-C.L.), Singapore National Eye Centre, Singapore; Ophthalmology and Visual Sciences Academic Clinical Program (J.S.M., H.S.O., M.A., Y.-C.L.), Duke-NUS Medical School, Singapore
| | - Marcus Ang
- Department of Cornea and External Eye Disease (J.S.M., H.S.O., M.A., L.T., Y.-C.L.), Singapore National Eye Centre, Singapore; Ophthalmology and Visual Sciences Academic Clinical Program (J.S.M., H.S.O., M.A., Y.-C.L.), Duke-NUS Medical School, Singapore
| | - Louis Tong
- Department of Cornea and External Eye Disease (J.S.M., H.S.O., M.A., L.T., Y.-C.L.), Singapore National Eye Centre, Singapore; Ocular Surface Research Group (L.T.), Singapore Eye Research Institute, Singapore; Eye Academic Clinical Program (L.T.), Duke-NUS Medical School, Singapore; Department of Ophthalmology (L.T.), Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Yu-Chi Liu
- From Tissue Engineering and Cell Therapy Group (C.L., M.T.-Y.L., I.X.Y.L., J.S.M., H.S.O., Y.-C.L.), Singapore Eye Research Institute, Singapore; Cornea and Refractive Surgery Group (C.L., J.S.M., H.S.O., Y.-C.L.), Singapore Eye Research Institute, Singapore; Department of Cornea and External Eye Disease (J.S.M., H.S.O., M.A., L.T., Y.-C.L.), Singapore National Eye Centre, Singapore; Ophthalmology and Visual Sciences Academic Clinical Program (J.S.M., H.S.O., M.A., Y.-C.L.), Duke-NUS Medical School, Singapore; Department of Ophthalmology (Y.-C.L.), National Taiwan University, Taiwan.
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Mäkinen P, Nättinen J, Aapola U, Pietilä J, Uusitalo H. Comparison of early changes in tear film protein profiles after small incision lenticule extraction (SMILE) and femtosecond LASIK (FS-LASIK) surgery. Clin Proteomics 2024; 21:11. [PMID: 38368345 PMCID: PMC10874072 DOI: 10.1186/s12014-024-09460-1] [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] [Received: 05/31/2023] [Accepted: 02/06/2024] [Indexed: 02/19/2024] Open
Abstract
BACKGROUND Small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (LASIK) are widely used surgical methods to correct myopia with comparable efficacy, predictability, and safety. We examined and compared the early changes of tear protein profiles after SMILE and FS-LASIK surgery in order to find possible differences in the initial corneal healing process. METHODS SMILE operations for 26 eyes were made with Visumax femtosecond laser. In FS-LASIK surgery for 30 eyes, the flaps were made with Ziemer FEMTO LDV Z6 femtosecond laser and stromal ablation with Wavelight EX500 excimer laser. Tear samples were collected preoperatively, and 1.5 h and 1 month postoperatively using glass microcapillary tubes. Tear protein identification and quantification were performed with sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS). RESULTS Immediately (1.5 h) after we found differences in 89 proteins after SMILE and in 123 after FS-LASIK operation compared to preoperative protein levels. Of these differentially expressed proteins, 48 proteins were common for both surgery types. There were, however, quantitative differences between SMILE and FS-LASIK. Upregulated proteins were mostly connected to inflammatory response and migration of the cells connected to immune system. One month after the operation protein expressions levels were returned to baseline levels with both surgical methods. CONCLUSIONS Our study showed that immediate changes in protein profiles after SMILE and FS-LASIK surgeries and differences between the methods are connected to inflammatory process, and the protein levels quickly return to the baseline within 1 month. The differences in protein profiles between the methods are probably associated with the different size of the epithelial wound induced.
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Affiliation(s)
- Petri Mäkinen
- SILK, Eye and Vision Research, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.
- Silmäasema Eye Hospital, Hämeenkatu 6, Tampere, 33100, Finland.
| | - Janika Nättinen
- SILK, Eye and Vision Research, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Ulla Aapola
- SILK, Eye and Vision Research, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Juhani Pietilä
- SILK, Eye and Vision Research, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Silmäasema Eye Hospital, Hämeenkatu 6, Tampere, 33100, Finland
| | - Hannu Uusitalo
- SILK, Eye and Vision Research, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- TAUH Eye Center, Tampere University Hospital, Tampere, Finland
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11
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Wong NSQ, Liu C, Lin MTY, Lee IXY, Tong L, Liu YC. Neuropathic Corneal Pain after Coronavirus Disease 2019 (COVID-19) Infection. Diseases 2024; 12:37. [PMID: 38391784 PMCID: PMC10887979 DOI: 10.3390/diseases12020037] [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] [Received: 01/13/2024] [Revised: 02/01/2024] [Accepted: 02/05/2024] [Indexed: 02/24/2024] Open
Abstract
INTRODUCTION This is a case report of a patient with neuropathic corneal pain after coronavirus disease 2019 (COVID-19) infection. METHODS A previously healthy 27-year-old female presented with bilateral eye pain accompanied by increased light sensitivity 5 months after COVID-19 infection. She was diagnosed with neuropathic corneal pain based on clear corneas without fluorescein staining, alongside the presence of microneuromas, dendritic cells, and activated stromal keratocytes identified bilaterally on in vivo confocal microscopy. RESULTS The patient's tear nerve growth factor, substance P, and calcitonin gene-related peptide levels were 5.9 pg/mL, 2978.7 pg/mL, and 1.1 ng/mL, respectively, for the right eye and 23.1 pg/mL, 4798.7 pg/mL, and 1.2 ng/mL, respectively, for the left eye, suggesting corneal neuroinflammatory status. After 6 weeks of topical 0.1% flurometholone treatment, decreased microneuroma size, less extensive dendritic cells, and reduced tear nerve growth factor and substance P levels were observed. The scores on the Ocular Pain Assessment Survey showed an improvement in burning sensation and light sensitivity, decreasing from 80% and 70% to 50% for both. CONCLUSIONS Neuropathic corneal pain is a potential post-COVID-19 complication that warrants ophthalmologists' and neurologists' attention.
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Affiliation(s)
- Natalie Shi Qi Wong
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Chang Liu
- Singapore Eye Research Institute, Singapore 169856, Singapore
| | | | | | - Louis Tong
- Singapore Eye Research Institute, Singapore 169856, Singapore
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore 168751, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Yu-Chi Liu
- Singapore Eye Research Institute, Singapore 169856, Singapore
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore 168751, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
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12
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Buonfiglio F, Wasielica-Poslednik J, Pfeiffer N, Gericke A. Diabetic Keratopathy: Redox Signaling Pathways and Therapeutic Prospects. Antioxidants (Basel) 2024; 13:120. [PMID: 38247544 PMCID: PMC10812573 DOI: 10.3390/antiox13010120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/10/2024] [Accepted: 01/16/2024] [Indexed: 01/23/2024] Open
Abstract
Diabetes mellitus, the most prevalent endocrine disorder, not only impacts the retina but also significantly involves the ocular surface. Diabetes contributes to the development of dry eye disease and induces morphological and functional corneal alterations, particularly affecting nerves and epithelial cells. These changes manifest as epithelial defects, reduced sensitivity, and delayed wound healing, collectively encapsulated in the context of diabetic keratopathy. In advanced stages of this condition, the progression to corneal ulcers and scarring further unfolds, eventually leading to corneal opacities. This critical complication hampers vision and carries the potential for irreversible visual loss. The primary objective of this review article is to offer a comprehensive overview of the pathomechanisms underlying diabetic keratopathy. Emphasis is placed on exploring the redox molecular pathways responsible for the aberrant structural changes observed in the cornea and tear film during diabetes. Additionally, we provide insights into the latest experimental findings concerning potential treatments targeting oxidative stress. This endeavor aims to enhance our understanding of the intricate interplay between diabetes and ocular complications, offering valuable perspectives for future therapeutic interventions.
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Affiliation(s)
- Francesco Buonfiglio
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (J.W.-P.); (N.P.)
| | | | | | - Adrian Gericke
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (J.W.-P.); (N.P.)
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Toh CJL, Liu C, Lee IXY, Lin MTY, Tong L, Liu YC. Clinical associations of corneal neuromas with ocular surface diseases. Neural Regen Res 2024; 19:140-147. [PMID: 37488855 PMCID: PMC10479835 DOI: 10.4103/1673-5374.375308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/04/2023] [Accepted: 04/06/2023] [Indexed: 07/26/2023] Open
Abstract
Corneal neuromas, also termed microneuromas, refer to microscopic, irregularly-shaped enlargements of terminal subbasal nerve endings at sites of nerve damage or injury. The formation of corneal neuromas results from damage to corneal nerves, such as following corneal pathology or corneal or intraocular surgeries. Initially, denervated areas of sensory nerve fibers become invaded by sprouts of intact sensory nerve fibers, and later injured axons regenerate and new sprouts called neuromas develop. In recent years, analysis of corneal nerve abnormalities including corneal neuromas which can be identified using in vivo confocal microscopy, a non-invasive imaging technique with microscopic resolution, has been used to evaluate corneal neuropathy and ocular surface dysfunction. Corneal neuromas have been shown to be associated with clinical symptoms of discomfort and dryness of eyes, and are a promising surrogate biomarker for ocular surface diseases, such as neuropathic corneal pain, dry eye disease, diabetic corneal neuropathy, neurotrophic keratopathy, Sjögren's syndrome, bullous keratopathy, post-refractive surgery, and others. In this review, we have summarized the current literature on the association between these ocular surface diseases and the presentation of corneal microneuromas, as well as elaborated on their pathogenesis, visualization via in vivo confocal microscopy, and utility in monitoring treatment efficacy. As current quantitative analysis on neuromas mainly relies on manual annotation and quantification, which is user-dependent and labor-intensive, future direction includes the development of artificial intelligence software to identify and quantify these potential imaging biomarkers in a more automated and sensitive manner, allowing it to be applied in clinical settings more efficiently. Combining imaging and molecular biomarkers may also help elucidate the associations between corneal neuromas and ocular surface diseases.
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Affiliation(s)
| | - Chang Liu
- Singapore Eye Research Institute, Singapore
| | | | | | - Louis Tong
- Singapore Eye Research Institute, Singapore
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Yu-Chi Liu
- Singapore Eye Research Institute, Singapore
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
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Mirzajani A, Bouyeh A, Khezri F, Jafarzadehpur E, Karimian F. How long does the recovery of corneal sensitivity in different corneal regions take after LASEK? Int J Ophthalmol 2023; 16:2056-2062. [PMID: 38111940 PMCID: PMC10700069 DOI: 10.18240/ijo.2023.12.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 08/01/2023] [Indexed: 12/20/2023] Open
Abstract
AIM To determine the corneal sensitivity recovery period after laser-assisted sub-epithelial keratectomy (LASEK) refractive surgery and investigate the effects of ablation depth on it. METHODS In this study examinations were performed on 90 right eyes of 90 people (34 males and 56 females) with an age range of 20-35 and an average of 22.26±3.8 years old. A sensation of 5 corneal regions, including the center and 4 mid-peripheral regions, i.e., nasal, inferior, temporal, and superior, each at a distance of 2 mm from the center of the cornea were measured with a Cochet-Bonnet esthesiometer device in 3-time points including before LASEK, 1 and 3mo after the surgery, respectively. LASEK was performed on individuals with stabilized myopia of -1.00 to -7.00 diopters and astigmatism of less than 2.00 diopters. Furthermore, the individuals were divided into three groups regarding ablation depth. RESULTS The highest level of corneal sensitivity before surgery was related to the center of the cornea (59.1±7.76), and the highest level of corneal sensitivity loss was also related to this region. The sensation of all measured corneal regions significantly reduced 1mo postoperatively and returned to their preoperative levels 3mo after surgery (mean of 5 corneal regions in levels of preoperation: 58.2±6.48, 1mo postoperation: 57.3±5.84, 3mo postoperation: 58.2±5.49; P<0.05). A significant relationship was found between ablation depth and corneal sensitivity changes in the center and temporal regions (P<0.05). CONCLUSION Corneal sensitivity in myopia and low astigmatism decreases after LASEK and reaches the preoperative level within 3mo. The depth of ablation during surgery affected the recovery of corneal sensitivity.
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Affiliation(s)
- Ali Mirzajani
- Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran 1449614535, Iran
| | - Aria Bouyeh
- Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran 1449614535, Iran
| | - Fatemeh Khezri
- Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran 1449614535, Iran
| | - Ebrahim Jafarzadehpur
- Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran 1449614535, Iran
| | - Farid Karimian
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran 1983963113, Iran
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Liu C, Lin MTY, Lee IXY, Mehta JS, Liu YC. Impact of corrected refractive power on the corneal denervation and ocular surface in small-incision lenticule extraction and LASIK. J Cataract Refract Surg 2023; 49:1106-1113. [PMID: 37867284 PMCID: PMC10583913 DOI: 10.1097/j.jcrs.0000000000001278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 10/24/2023]
Abstract
PURPOSE To evaluate the impact of corrected refractive power on the corneal denervation and ocular surface in small-incision lenticule extraction (SMILE) and laser in situ keratomileusis (LASIK). SETTING Singapore National Eye Center, Singapore. DESIGN Prospective study. METHODS 88 eyes undergoing SMILE or LASIK were divided into low-moderate (manifest refractive spherical equivalent [MRSE] <-6.0 diopters [D]) and high myopic (MRSE ≥-6.0 D) groups. In vivo confocal microscopy and clinical assessments were performed preoperatively and at 1 month, 3 months, 6 months, and 12 months postoperatively. RESULTS In SMILE, high myopic treatment presented with significantly greater reduction in the corneal nerve fiber area (CNFA) and nerve fiber fractal dimension (CFracDim) compared with low-moderate myopic treatment (both P < .05). There was a significant and negative correlation between the corrected MRSE and the reduction in corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length, CNFA, and CFracDim after SMILE (r = -0.38 to -0.66, all P < .05). In LASIK, a significant correlation between the MRSE and the changes in CNBD, corneal nerve fiber total branch density, CNFA (r = -0.37 to -0.41), and corneal nerve fiber width (r = 0.43) was observed (all P < .05). Compared with SMILE, LASIK had greater reduction in CNBD and CNFA for every diopter increase in the corrected MRSE. High myopic SMILE, compared with low-moderate myopic SMILE, resulted in significantly lower tear break-up time at 1 and 6 months (both P < .05). The changes in CNFA and CFracDim were significantly associated with Schirmer test values (both P < .001). CONCLUSIONS Postoperative corneal denervation was related to corrected refractive power in both SMILE and LASIK. With the same refractive correction, LASIK led to more prominent corneal denervation.
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Affiliation(s)
- Chang Liu
- From the Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore (C. Liu, Lin, Lee, Mehta, Y.-C. Liu); Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore (C. Liu, Mehta); Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore (Mehta, Y.-C. Liu); Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore (Mehta, Y.-C. Liu); Department of Ophthalmology, National Taiwan University, Taiwan (Y.-C. Liu)
| | - Molly Tzu-Yu Lin
- From the Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore (C. Liu, Lin, Lee, Mehta, Y.-C. Liu); Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore (C. Liu, Mehta); Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore (Mehta, Y.-C. Liu); Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore (Mehta, Y.-C. Liu); Department of Ophthalmology, National Taiwan University, Taiwan (Y.-C. Liu)
| | - Isabelle Xin Yu Lee
- From the Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore (C. Liu, Lin, Lee, Mehta, Y.-C. Liu); Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore (C. Liu, Mehta); Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore (Mehta, Y.-C. Liu); Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore (Mehta, Y.-C. Liu); Department of Ophthalmology, National Taiwan University, Taiwan (Y.-C. Liu)
| | - Jodhbir S. Mehta
- From the Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore (C. Liu, Lin, Lee, Mehta, Y.-C. Liu); Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore (C. Liu, Mehta); Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore (Mehta, Y.-C. Liu); Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore (Mehta, Y.-C. Liu); Department of Ophthalmology, National Taiwan University, Taiwan (Y.-C. Liu)
| | - Yu-Chi Liu
- From the Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore (C. Liu, Lin, Lee, Mehta, Y.-C. Liu); Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore (C. Liu, Mehta); Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore (Mehta, Y.-C. Liu); Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore (Mehta, Y.-C. Liu); Department of Ophthalmology, National Taiwan University, Taiwan (Y.-C. Liu)
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Zhao L, Zhang Y, Duan H, Yang T, Zhou Y, Ma B, Chen Y, Qi H. Clinical Characteristics and Tear Film Biomarkers in Patients With Chronic Dry Eye Disease After Femtosecond Laser-Assisted Laser in Situ Keratomileusis. J Refract Surg 2023; 39:556-563. [PMID: 37578178 DOI: 10.3928/1081597x-20230717-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
PURPOSE To investigate clinical characteristics and tear film biomarkers of patients with chronic dry eye disease (DED) following femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). METHODS Patients were divided into the chronic DED after FS-LASIK (n = 36), DED without FS-LASIK (n = 39), and normal control (without FS-LASIK; n = 34) groups. Dry eye, pain, and psychological-related symptoms were evaluated using the Ocular Surface Disease Index (OSDI), Numerical Rating Scale (NRS), Neuropathic Pain Symptom Inventory Modified for the Eye (NPSI-Eye), and Hamilton Anxiety Rating Scale (HAMA) questionnaires. Ocular surface parameters, tear cytokines, and neuropeptide concentrations were evaluated with specific tests. RESULTS The DED after FS-LASIK group showed higher corneal fluorescein staining scores, but lower OSDI and NPSI-Eye scores than the DED without FS-LASIK group (all P < .05). Corneal sensitivity and nerve density decreased in the DED after FS-LASIK group (all P < .01). Granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-17A, IL-23, alpha-melanocyte stimulating hormone (α-MSH), oxytocin, and substance P levels were highest in the DED after FS-LASIK group, followed by the DED without FS-LASIK and normal control groups (all P < .05). Interferon-γ and neurotensin levels were only significantly higher in the DED after FS-LASIK group (all P < .05). CONCLUSIONS Patients with chronic DED after FS-LASIK showed milder ocular symptoms, greater epithelial damage, and higher levels of tear inflammatory cytokines and neuropeptides than patients with DED without FS-LASIK, indicating that the nervous and immune systems may play significant roles in FS-LASIK-related chronic DED development. [J Refract Surg. 2023;39(8):556-563.].
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Metabolomics in Corneal Diseases: A Narrative Review from Clinical Aspects. Metabolites 2023; 13:metabo13030380. [PMID: 36984820 PMCID: PMC10055016 DOI: 10.3390/metabo13030380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/25/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023] Open
Abstract
Corneal pathologies may have subtle manifestations in the initial stages, delaying diagnosis and timely treatment. This can lead to irreversible visual loss. Metabolomics is a rapidly developing field that allows the study of metabolites in a system, providing a complementary tool in the early diagnosis and management of corneal diseases. Early identification of biomarkers is key to prevent disease progression. The advancement of nuclear magnetic resonance and mass spectrometry allows the identification of new biomarkers in the analysis of tear, cornea, and aqueous humor. Novel perspectives on disease mechanisms are identified, which provide vital information for potential targeted therapies in the future. Current treatments are analyzed at a molecular level to offer further information regarding their efficacy. In this article, we provide a comprehensive review of the metabolomic studies undertaken in the cornea and various pathologies such as dry eye disease, Sjogren’s syndrome, keratoconus, post-refractive surgery, contact lens wearers, and diabetic corneas. Lastly, we discuss the exciting future that metabolomics plays in cornea research.
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Cui G, Di Y, Yang S, Chen D, Li Y. Efficacy of small-incision lenticule extraction surgery in high astigmatism: A meta-analysis. Front Med (Lausanne) 2023; 9:1100241. [PMID: 36743675 PMCID: PMC9892059 DOI: 10.3389/fmed.2022.1100241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 12/30/2022] [Indexed: 01/20/2023] Open
Abstract
Purpose This study aimed to evaluate the efficacy of small-incision lenticule extraction (SMILE) in improving vision and visual quality and correcting astigmatism for the treatment of high astigmatism. Methods Eligible studies and studies comparing the efficacy of SMILE with femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) or transepithelial photorefractive keratectomy (T-PRK) for high astigmatism (≥2.00 D) were identified in PubMed, Embase, and the Cochrane Central Register of Controlled Trials, searched from their inception to 29 May 2022. The references of all searched studies were checked as supplements. The risk of bias was evaluated for each eligible study. The literature was screened according to the inclusion and exclusion criteria, and relative data were extracted. Data were extracted and analyzed by ReviewManager 5.4. The primary outcome was post-operative uncorrected distance visual acuity (UDVA). The secondary outcomes included corneal aberrations and vector parameters. The weight mean difference (WMD) and their 95% confidence intervals (95% CI) were used to assess the strength of the association. Results A total of six studies including 380 astigmatism eyes were involved, with 211 high-astigmatism eyes and 31 low-astigmatism eyes undergoing SMILE surgery, 94 high-astigmatism eyes undergoing FS-LASIK surgery, and 44 high-astigmatism eyes undergoing T-PRK surgery. Compared with non-SMILE, SMILE induced more astigmatism (weighted mean difference [WMD] = -0.07, 95% CI [-0.12 to -0.02], P = 0.005) and fewer sphere aberrations (WMD = -0.12, 95% CI [-0.17 to -0.08], P < 0.00001). The post-operative UDVA, sphere, spherical equivalent (SE), and higher order aberrations in different surgeries were likewise equivalent. The difference vector and index of success were significantly higher, and the surgically induced astigmatism vector, correction index, and magnitude of error were significantly lower in SMILE. Conclusion This meta-analysis suggests that SMILE, FS-LASIK, and T-PRK show excellent efficacy, predictability, and safety for myopia. SMILE exhibited less astigmatism refraction predictability and less surgically induced spherical aberrations. There may be more under-correction in SMILE. More randomized, prospective, and large sample-sized studies are needed to confirm these conclusions in the long term.
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Affiliation(s)
- Ge Cui
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China,Key Laboratory of Ocular Fundus Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yu Di
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China,Key Laboratory of Ocular Fundus Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Shan Yang
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China,Key Laboratory of Ocular Fundus Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Di Chen
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China,Key Laboratory of Ocular Fundus Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China,Di Chen,
| | - Ying Li
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China,Key Laboratory of Ocular Fundus Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China,*Correspondence: Ying Li,
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Variability of autonomic nerve activity in dry eye with decreased tear stability. PLoS One 2022; 17:e0276945. [DOI: 10.1371/journal.pone.0276945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/18/2022] [Indexed: 11/17/2022] Open
Abstract
The autonomic nervous system plays a crucial role in the maintenance of homeostasis. Neurogenic inflammation due to decreased stability of tear film may induce changes in autonomic nerve activity, which could be associated with symptom expression.This study aimed to measure biological parameters that represent autonomic nerve activity in dry eye (DE)s caused by tear film dysfunction and investigate their relationship with symptom intensity. This prospective, cross-sectional, comparative study evaluated 34 eyes of 34 participants (mean age: 52.5 ± 13.4 years; range: 20–81 years) without keratoconjunctival damage. Nineteen eyes in the DE group showed DE symptoms and tear break-up time (TBUT) of ≤5 seconds (short TBUT DE); the 15 eyes in the non-DE group showed no DE symptoms. Autonomic nerve activity was measured for 10 minutes—starting and ending 5 minutes before and after instilling ophthalmic solution—and evaluated using the low-frequency component (LF) to the high-frequency component (HF) ratio of heart rate variability (autonomic balance). The pre-ophthalmic solution administration LF/HF ratio was not significantly different (P = 0.59) between the two groups, however, the standard deviation of the LF/HF ratio (LF/HF-SD) tended to be higher in the DE group than that in the non-DE group (P = 0.086). The DE symptom intensity was significantly related to LF/HF-SD (P = 0.005), which significantly decreased after ophthalmic solution administration in the DE group (P = 0.04). The large fluctuations in autonomic balance may be key for the understanding of the mechanism underlying DE symptoms.
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So WZ, Qi Wong NS, Tan HC, Yu Lin MT, Yu Lee IX, Mehta JS, Liu YC. Diabetic corneal neuropathy as a surrogate marker for diabetic peripheral neuropathy. Neural Regen Res 2022; 17:2172-2178. [PMID: 35259825 PMCID: PMC9083173 DOI: 10.4103/1673-5374.327364] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Diabetic neuropathy is a prevalent microvascular complication of diabetes mellitus, affecting nerves in all parts of the body including corneal nerves and peripheral nervous system, leading to diabetic corneal neuropathy and diabetic peripheral neuropathy, respectively. Diabetic peripheral neuropathy is diagnosed in clinical practice using electrophysiological nerve conduction studies, clinical scoring, and skin biopsies. However, these diagnostic methods have limited sensitivity in detecting small-fiber disease, hence they do not accurately reflect the status of diabetic neuropathy. More recently, analysis of alterations in the corneal nerves has emerged as a promising surrogate marker for diabetic peripheral neuropathy. In this review, we will discuss the relationship between diabetic corneal neuropathy and diabetic peripheral neuropathy, elaborating on the foundational aspects of each: pathogenesis, clinical presentation, evaluation, and management. We will further discuss the relevance of diabetic corneal neuropathy in detecting the presence of diabetic peripheral neuropathy, particularly early diabetic peripheral neuropathy; the correlation between the severity of diabetic corneal neuropathy and that of diabetic peripheral neuropathy; and the role of diabetic corneal neuropathy in the stratification of complications of diabetic peripheral neuropathy.
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Affiliation(s)
- Wei Zheng So
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; Singapore Eye Research Institute, Singapore, Singapore
| | - Natalie Shi Qi Wong
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; Singapore Eye Research Institute, Singapore, Singapore
| | - Hong Chang Tan
- Department of Endocrinology, Singapore General Hospital, Singapore, Singapore
| | | | | | - Jodhbir S Mehta
- Singapore Eye Research Institute; Department of Cornea and External Eye Disease, Singapore National Eye Centre; Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Yu-Chi Liu
- Singapore Eye Research Institute; Department of Cornea and External Eye Disease, Singapore National Eye Centre; Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
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21
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Yousefifard M, Askarian-Amiri S, Nasseri Maleki S, Rafiei Alavi SN, Madani Neishaboori A, Haghani L, Vaccaro AR, Harrop JS, Lu Y, Rahimi-Movaghar V, Hosseini M. Combined application of neural stem/progenitor cells and scaffolds on locomotion recovery following spinal cord injury in rodents: a systematic review and meta-analysis. Neurosurg Rev 2022; 45:3469-3488. [DOI: 10.1007/s10143-022-01859-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 07/20/2022] [Accepted: 09/01/2022] [Indexed: 11/29/2022]
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22
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Puri S, Kenyon BM, Hamrah P. Immunomodulatory Role of Neuropeptides in the Cornea. Biomedicines 2022; 10:1985. [PMID: 36009532 PMCID: PMC9406019 DOI: 10.3390/biomedicines10081985] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 12/21/2022] Open
Abstract
The transparency of the cornea along with its dense sensory innervation and resident leukocyte populations make it an ideal tissue to study interactions between the nervous and immune systems. The cornea is the most densely innervated tissue of the body and possesses both immune and vascular privilege, in part due to its unique repertoire of resident immune cells. Corneal nerves produce various neuropeptides that have a wide range of functions on immune cells. As research in this area expands, further insights are made into the role of neuropeptides and their immunomodulatory functions in the healthy and diseased cornea. Much remains to be known regarding the details of neuropeptide signaling and how it contributes to pathophysiology, which is likely due to complex interactions among neuropeptides, receptor isoform-specific signaling events, and the inflammatory microenvironment in disease. However, progress in this area has led to an increase in studies that have begun modulating neuropeptide activity for the treatment of corneal diseases with promising results, necessitating the need for a comprehensive review of the literature. This review focuses on the role of neuropeptides in maintaining the homeostasis of the ocular surface, alterations in disease settings, and the possible therapeutic potential of targeting these systems.
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Affiliation(s)
- Sudan Puri
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Brendan M. Kenyon
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
| | - Pedram Hamrah
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
- Departments of Immunology and Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
- Cornea Service, Tufts New England Eye Center, Boston, MA 02111, USA
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23
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Biochemistry of human tear film: A review. Exp Eye Res 2022; 220:109101. [DOI: 10.1016/j.exer.2022.109101] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 04/18/2022] [Accepted: 04/26/2022] [Indexed: 12/13/2022]
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Frutos-Rincón L, Gómez-Sánchez JA, Íñigo-Portugués A, Acosta MC, Gallar J. An Experimental Model of Neuro-Immune Interactions in the Eye: Corneal Sensory Nerves and Resident Dendritic Cells. Int J Mol Sci 2022; 23:ijms23062997. [PMID: 35328417 PMCID: PMC8951464 DOI: 10.3390/ijms23062997] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/28/2022] [Accepted: 03/04/2022] [Indexed: 12/04/2022] Open
Abstract
The cornea is an avascular connective tissue that is crucial, not only as the primary barrier of the eye but also as a proper transparent refractive structure. Corneal transparency is necessary for vision and is the result of several factors, including its highly organized structure, the physiology of its few cellular components, the lack of myelinated nerves (although it is extremely innervated), the tightly controlled hydration state, and the absence of blood and lymphatic vessels in healthy conditions, among others. The avascular, immune-privileged tissue of the cornea is an ideal model to study the interactions between its well-characterized and dense sensory nerves (easily accessible for both focal electrophysiological recording and morphological studies) and the low number of resident immune cell types, distinguished from those cells migrating from blood vessels. This paper presents an overview of the corneal structure and innervation, the resident dendritic cell (DC) subpopulations present in the cornea, their distribution in relation to corneal nerves, and their role in ocular inflammatory diseases. A mouse model in which sensory axons are constitutively labeled with tdTomato and DCs with green fluorescent protein (GFP) allows further analysis of the neuro-immune crosstalk under inflammatory and steady-state conditions of the eye.
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Affiliation(s)
- Laura Frutos-Rincón
- Instituto de Neurociencias, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (A.Í.-P.); (M.C.A.); (J.G.)
- The European University of Brain and Technology-NeurotechEU, 03550 San Juan de Alicante, Spain
| | - José Antonio Gómez-Sánchez
- Instituto de Neurociencias, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (A.Í.-P.); (M.C.A.); (J.G.)
- Correspondence: ; Tel.: +34-965-91-9594
| | - Almudena Íñigo-Portugués
- Instituto de Neurociencias, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (A.Í.-P.); (M.C.A.); (J.G.)
| | - M. Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (A.Í.-P.); (M.C.A.); (J.G.)
- The European University of Brain and Technology-NeurotechEU, 03550 San Juan de Alicante, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (A.Í.-P.); (M.C.A.); (J.G.)
- The European University of Brain and Technology-NeurotechEU, 03550 San Juan de Alicante, Spain
- Instituto de Investigación Biomédica y Sanitaria de Alicante, 03010 Alicante, Spain
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Teo AWJ, Mansoor H, Sim N, Lin MTY, Liu YC. In Vivo Confocal Microscopy Evaluation in Patients with Keratoconus. J Clin Med 2022; 11:393. [PMID: 35054085 PMCID: PMC8778820 DOI: 10.3390/jcm11020393] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 02/05/2023] Open
Abstract
Keratoconus is the most common primary corneal ectasia characterized by progressive focal thinning. Patients experience increased irregular astigmatism, decreased visual acuity and corneal sensitivity. Corneal collagen crosslinking (CXL), a minimally invasive procedure, is effective in halting disease progression. Historically, keratoconus research was confined to ex vivo settings. In vivo confocal microscopy (IVCM) has been used to examine the corneal microstructure clinically. In this review, we discuss keratoconus cellular changes evaluated by IVCM before and after CXL. Cellular changes before CXL include decreased keratocyte and nerve densities, disorganized subbasal nerves with thickening, increased nerve tortuosity and shortened nerve fibre length. Repopulation of keratocytes occurs up to 1 year post procedure. IVCM also correlates corneal nerve status to functional corneal sensitivity. Immediately after CXL, there is reduced nerve density and keratocyte absence due to mechanical removal of the epithelium and CXL effect. Nerve regeneration begins after 1 month, with nerve fibre densities recovering to pre-operative levels between 6 months to 1 year and remains stable up to 5 years. Nerves remain tortuous and nerve densities are reduced. Corneal sensitivity is reduced immediately postoperatively but recovers with nerve regeneration. Our article provides comprehensive review on the use of IVCM imaging in keratoconus patients.
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Affiliation(s)
- Alvin Wei Jun Teo
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore 168751, Singapore;
| | - Hassan Mansoor
- Al Shifa Trust Eye Hospital, Jhelum Road, Rawalpindi 46000, Pakistan;
| | - Nigel Sim
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore 168751, Singapore;
| | - Molly Tzu-Yu Lin
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore;
| | - Yu-Chi Liu
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore 168751, Singapore;
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore;
- Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore 169856, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
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26
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Luna C, Quirce S, Aracil-Marco A, Belmonte C, Gallar J, Acosta MC. Unilateral Corneal Insult Also Alters Sensory Nerve Activity in the Contralateral Eye. Front Med (Lausanne) 2021; 8:767967. [PMID: 34869482 PMCID: PMC8634144 DOI: 10.3389/fmed.2021.767967] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/11/2021] [Indexed: 01/21/2023] Open
Abstract
After the unilateral inflammation or nerve lesion of the ocular surface, the ipsilateral corneal sensory nerve activity is activated and sensitized, evoking ocular discomfort, irritation, and pain referred to the affected eye. Nonetheless, some patients with unilateral ocular inflammation, infection, or surgery also reported discomfort and pain in the contralateral eye. We explored the possibility that such altered sensations in the non-affected eye are due to the changes in their corneal sensory nerve activity in the contralateral, not directly affected eye. To test that hypothesis, we recorded the impulse activity of the corneal mechano- and polymodal nociceptor and cold thermoreceptor nerve terminals in both eyes of guinea pigs, subjected unilaterally to three different experimental conditions (UV-induced photokeratitis, microkeratome corneal surgery, and chronic tear deficiency caused by removal of the main lacrimal gland), and in eyes of naïve animals ex vivo. Overall, after unilateral eye damage, the corneal sensory nerve activity appeared to be also altered in the contralateral eye. Compared with the naïve guinea pigs, animals with unilateral UV-induced mild corneal inflammation, showed on both eyes an inhibition of the spontaneous and stimulus-evoked activity of cold thermoreceptors, and increased activity in nociceptors affecting both the ipsilateral and the contralateral eye. Unilateral microkeratome surgery affected the activity of nociceptors mostly, inducing sensitization in both eyes. The removal of the main lacrimal gland reduced tear volume and increased the cold thermoreceptor activity in both eyes. This is the first direct demonstration that unilateral corneal nerve lesion, especially ocular surface inflammation, functionally affects the activity of the different types of corneal sensory nerves in both the ipsilateral and contralateral eyes. The mechanisms underlying the contralateral affectation of sensory nerves remain to be determined, although available data support the involvement of neuroimmune interactions. The parallel alteration of nerve activity in contralateral eyes has two main implications: a) in the experimental design of both preclinical and clinical studies, where the contralateral eyes cannot be considered as a control; and, b) in the clinical practice, where clinicians must consider the convenience of treating both eyes of patients with unilateral ocular conditions to avoid pain and secondary undesirable effects in the fellow eye.
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Affiliation(s)
- Carolina Luna
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Susana Quirce
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Adolfo Aracil-Marco
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Carlos Belmonte
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain.,Instituto de Investigación Sanitaria y Biomédica de Alicante, San Juan de Alicante, Spain
| | - M Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
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27
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Hwang DDJ, Lee SJ, Kim JH, Lee SM. The Role of Neuropeptides in Pathogenesis of Dry Dye. J Clin Med 2021; 10:4248. [PMID: 34575359 PMCID: PMC8471988 DOI: 10.3390/jcm10184248] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/07/2021] [Accepted: 09/14/2021] [Indexed: 12/29/2022] Open
Abstract
Neuropeptides are known as important mediators between the nervous and immune systems. Recently, the role of the corneal nerve in the pathogenesis of various ocular surface diseases, including dry eye disease, has been highlighted. Neuropeptides are thought to be important factors in the pathogenesis of dry eye disease, as suggested by the well-known role between the nervous and immune systems, and several recently published studies have elucidated the previously unknown pathogenic mechanisms involved in the role of the neuropeptides secreted from the corneal nerves in dry eye disease. Here, we reviewed the emerging concept of neurogenic inflammation as one of the pathogenic mechanisms of dry eye disease, the recent results of related studies, and the direction of future research.
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Affiliation(s)
- Daniel Duck-Jin Hwang
- Department of Ophthalmology, HanGil Eye Hospital, Incheon 21388, Korea;
- Department of Ophthalmology, College of Medicine, Catholic Kwandong University, Incheon 21388, Korea
| | - Seok-Jae Lee
- Fight against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul 03080, Korea; (S.-J.L.); (J.-H.K.)
- Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul 03080, Korea
| | - Jeong-Hun Kim
- Fight against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul 03080, Korea; (S.-J.L.); (J.-H.K.)
- Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul 03080, Korea
- Department of Ophthalmology, College of Medicine, Seoul National University, Seoul 03080, Korea
- Advanced Biomedical Research Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon 34141, Korea
| | - Sang-Mok Lee
- Department of Ophthalmology, HanGil Eye Hospital, Incheon 21388, Korea;
- Department of Ophthalmology, College of Medicine, Catholic Kwandong University, Incheon 21388, Korea
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Chin JY, Lin MTY, Lee IXY, Mehta JS, Liu YC. Tear Neuromediator and Corneal Denervation Following SMILE. J Refract Surg 2021; 37:516-523. [PMID: 34388069 DOI: 10.3928/1081597x-20210423-01] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE To investigate the changes in tear neuromediators and corneal subbasal nerve plexus following small incision lenticule extraction (SMILE) and to study its association with different refractive power of corrections. METHODS Thirty patients were included for tear neuromediator analysis (40 eyes) and corneal nerve analysis using in vivo confocal microscopy scans (20 eyes). Tear samples were collected preoperatively and 1 week and 1, 3, 6, and 12 months postoperatively and analyzed for the substance P, calcitonin gene-related peptide (CGRP), and nerve growth factor (NGF) concentrations using the enzyme-linked immunosor-bent assay (ELISA). RESULTS Corneal nerve fiber density (CNFD), corneal nerve fiber length (CNFL), and corneal nerve branch density (CNBD) decreased significantly postoperatively, then gradually increased from 3 months onward, but did not recover to the baseline levels at 12 months. Tear substance P and CGRP levels remained stable over 12 months. Tear NGF levels demonstrated a small peak at 1 week before decreasing significantly compared to preoperative levels at 6 months (P = .03) and 12 months (P = .007). The 1-month reduction in CNFL, tear substance P, and CGRP concentrations were significantly correlated with the corrected spherical equivalent (SE) (r = 0.71 for CNFL; r = -0.33 to -0.52 at different time points for substance P and CGRP, respectively, all P < .05). Compared to the low to moderate myopia group, the high myopia group (corrected SE greater than -6.00 diopters) had a significantly greater decrease in CNFD, significantly higher tear substance P concentrations at 1 week, 1 month, and 6 months, and significantly higher tear CGRP concentrations at 1 and 6 months. CONCLUSIONS These results provide new insight into the neurobiological responses and their potential implications in corneal nerve damage and recovery after SMILE. High myopia treatment was associated with greater corneal denervation and neuroinflammation. [J Refract Surg. 2021;37(8):516-523.].
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