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Pang K, Lennikov A, Yang M. Hypoxia adaptation in the cornea: Current animal models and underlying mechanisms. Animal Model Exp Med 2021; 4:300-310. [PMID: 34977481 PMCID: PMC8690994 DOI: 10.1002/ame2.12192] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/03/2021] [Accepted: 11/08/2021] [Indexed: 12/14/2022] Open
Abstract
The cornea is an avascular, transparent tissue that is essential for visual function. Any disturbance to the corneal transparency will result in a severe vision loss. Due to the avascular nature, the cornea acquires most of the oxygen supply directly or indirectly from the atmosphere. Corneal tissue hypoxia has been noticed to influence the structure and function of the cornea for decades. The etiology of hypoxia of the cornea is distinct from the rest of the body, mainly due to the separation of cornea from the atmosphere, such as prolonged contact lens wearing or closed eyes. Corneal hypoxia can also be found in corneal inflammation and injury when a higher oxygen requirement exceeds the oxygen supply. Systemic hypoxic state during lung diseases or high altitude also leads to corneal hypoxia when a second oxygen consumption route from aqueous humor gets blocked. Hypoxia affects the cornea in multiple aspects, including disturbance of the epithelium barrier function, corneal edema due to endothelial dysfunction and metabolism changes in the stroma, and thinning of corneal stroma. Cornea has also evolved mechanisms to adapt to the hypoxic state initiated by the activation of hypoxia inducible factor (HIF). The aim of this review is to introduce the pathology of cornea under hypoxia and the mechanism of hypoxia adaptation, to discuss the current animal models used in this field, and future research directions.
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Affiliation(s)
- Kunpeng Pang
- Harvard Medical School Department of OphthalmologySchepens Eye Research InstituteMassachusetts Eye and EarBostonMassachusettsUSA
- Department of OphthalmologyQilu Hospital of Shandong UniversityQingdaoChina
| | - Anton Lennikov
- Harvard Medical School Department of OphthalmologySchepens Eye Research InstituteMassachusetts Eye and EarBostonMassachusettsUSA
| | - Menglu Yang
- Harvard Medical School Department of OphthalmologySchepens Eye Research InstituteMassachusetts Eye and EarBostonMassachusettsUSA
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Lindström BE, Høeg TB. Ultramarathon-induced Corneal Edema-A Case Report. Curr Sports Med Rep 2021; 20:13-15. [PMID: 33395125 DOI: 10.1249/jsr.0000000000000796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
| | - Tracy Beth Høeg
- Department of Physical Medicine and Rehabilitation, University of California-Davis, Davis, CA
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Jaki Mekjavic P, Tipton MJ, Mekjavic IB. The eye in extreme environments. Exp Physiol 2020; 106:52-64. [DOI: 10.1113/ep088594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/05/2020] [Indexed: 11/08/2022]
Affiliation(s)
- Polona Jaki Mekjavic
- University Medical Centre Ljubljana Eye Clinic Ljubljana Slovenia
- Faculty of Medicine University of Ljubljana Ljubljana Slovenia
- Department of Automation Biocybernetics and Robotics Jozef Stefan Institute Ljubljana Slovenia
| | - Michael J. Tipton
- School of Sport Health and Exercise Science University of Portsmouth Portsmouth UK
| | - Igor B Mekjavic
- Department of Automation Biocybernetics and Robotics Jozef Stefan Institute Ljubljana Slovenia
- Department of Biomedical Physiology and Kinesiology Simon Fraser University Burnaby British Columbia Canada
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Abstract
Exercise is universally recognized for its health benefits and distance running has long been a popular form of exercise and sport. Ultramarathons, defined as races longer than a marathon, have become increasingly popular in recent years. The diverse ultramarathon distances and courses provide additional challenges in race performance and medical coverage for these events. As the sport grows in popularity, more literature has become available regarding ultramarathon-specific illnesses and injuries, nutrition guidelines, psychology, physiologic changes, and equipment. This review focuses on recent findings and trends in ultramarathon running.
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Affiliation(s)
- Jack Spittler
- UCH-A.F. Williams Family Medicine Center at Stapleton, Denver, CO
| | - Lauren Oberle
- University of Colorado-Denver, Anschutz Medical Campus, Denver, CO
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Moshirfar M, Murri MS, Shah TJ, Skanchy DF, Tuckfield JQ, Ronquillo YC, Birdsong OC, Hofstedt D, Hoopes PC. A Review of Corneal Endotheliitis and Endotheliopathy: Differential Diagnosis, Evaluation, and Treatment. Ophthalmol Ther 2019; 8:195-213. [PMID: 30859513 PMCID: PMC6514041 DOI: 10.1007/s40123-019-0169-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Indexed: 12/13/2022] Open
Abstract
The corneal endothelium plays an integral role in regulating corneal hydration and clarity. Endotheliitis, defined as inflammation of the corneal endothelium, may disrupt endothelial function and cause subsequent visual changes. Corneal endotheliitis is characterized by corneal edema, the presence of keratic precipitates, anterior chamber inflammation, and occasionally limbal injection, neovascularization, and co-existing or superimposed uveitis. The disorder is classified into four subgroups: linear, sectoral, disciform, and diffuse. Its etiology is extensive and, although commonly viral, may be medication-related, procedural, fungal, zoological, environmental, or systemic. Not all cases of endothelial dysfunction leading to corneal edema are inflammatory in nature. Therefore, it is imperative that practitioners consider a broad differential for patients presenting with possible endotheliitis, as well as familiarize themselves with appropriate diagnostic and therapeutic modalities.
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Affiliation(s)
- Majid Moshirfar
- John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA.
- Utah Lions Eye Bank, Murray, UT, USA.
- HDR Research Center, Hoopes Vision, Draper, UT, USA.
| | - Michael S Murri
- John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Tirth J Shah
- Department of Ophthalmology, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
- Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa, IA, USA
| | - David F Skanchy
- McGovern Medical School, The University of Texas Health Science Center, Houston, TX, USA
- W.K. Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, MI, USA
| | - James Q Tuckfield
- Kansas City University of Medicine and Biosciences, Kansas City, MO, USA
| | | | | | - Daniel Hofstedt
- Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, USA
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Moshirfar M, Y. Liu H, Vaidyanathan U, N. Somani A, C. Hopping G, R. Barnes J, B. Heiland M, B. Rosen D, N. Motlagh M, C. Hoopes P. Diagnosis and Management of Pseudoguttata: A Literature Review. MEDICAL HYPOTHESIS, DISCOVERY & INNOVATION OPHTHALMOLOGY JOURNAL 2019; 8:156-162. [PMID: 31598518 PMCID: PMC6778462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Corneal pseudoguttata (PG), also known as pseudoguttae or secondary guttata, is a transient, reversible endothelial edema commonly associated with anterior segment pathology. While considered rare, PG presents on slit-lamp examination more commonly than originally thought. We have clinically observed PG after refractive surgeries, in association with infectious keratitis, and following medication use. PG presents as dark lesions on slit-lamp exam with specular illumination, similar to primary corneal guttata. PG is distinct from guttata because PG resolves over time and does not involve Descemet's membrane. Other ocular findings that may be confused with guttata include endothelial blebs (EB) and endothelial denudation (ED). EB are possibly a type of PG that present after contact lens use or hypoxia. ED is a distinct entity that is characterized by loss of endothelial cells without involvement of Descemet's membrane. Confocal microscopy may be useful in differentiating these four endothelial lesions, with differences in border definition and the presence of hyperreflective areas two main distinctions. PG presents as a hyporeflective, elevated shape without clear borders on confocal microscopy. PG, EB, and ED can resolve with time without the need for surgical intervention, unlike corneal guttata. Treatment of the underlying condition will lead to resolution of both PG and EB.
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Affiliation(s)
- Majid Moshirfar
- John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, School of Medicine, University of Utah, Salt Lake City, UT, USA
- Utah Lions Eye Bank, Murray, UT, USA
- Hoopes Durrie Rivera Research Center, Hoopes Vision, Draper, UT, USA
| | - Harry Y. Liu
- Health Science Center, McGovern Medical School, University of Texas, Houston, TX, USA
| | - Uma Vaidyanathan
- Health Science Center, McGovern Medical School, University of Texas, Houston, TX, USA
| | - Anisha N. Somani
- School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Grant C. Hopping
- College of Medicine-Phoenix, University of Arizona, Phoenix, AZ, USA
| | - James R. Barnes
- College of Medicine-Phoenix, University of Arizona, Phoenix, AZ, USA
| | | | - David B. Rosen
- College of Medicine-Phoenix, University of Arizona, Phoenix, AZ, USA
| | | | - Phillip C. Hoopes
- Hoopes Durrie Rivera Research Center, Hoopes Vision, Draper, UT, USA
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