1
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Suh A, Hampel G, Vinjamuri A, Ong J, Kamran SA, Waisberg E, Paladugu P, Zaman N, Sarker P, Tavakkoli A, Lee AG. Oculomics analysis in multiple sclerosis: Current ophthalmic clinical and imaging biomarkers. Eye (Lond) 2024:10.1038/s41433-024-03132-y. [PMID: 38858520 DOI: 10.1038/s41433-024-03132-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 03/18/2024] [Accepted: 05/07/2024] [Indexed: 06/12/2024] Open
Abstract
Multiple Sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system (CNS) characterized by inflammation, demyelination, and axonal damage. Early recognition and treatment are important for preventing or minimizing the long-term effects of the disease. Current gold standard modalities of diagnosis (e.g., CSF and MRI) are invasive and expensive in nature, warranting alternative methods of detection and screening. Oculomics, the interdisciplinary combination of ophthalmology, genetics, and bioinformatics to study the molecular basis of eye diseases, has seen rapid development through various technologies that detect structural, functional, and visual changes in the eye. Ophthalmic biomarkers (e.g., tear composition, retinal nerve fibre layer thickness, saccadic eye movements) are emerging as promising tools for evaluating MS progression. The eye's structural and embryological similarity to the brain makes it a potentially suitable assessment of neurological and microvascular changes in CNS. In the advent of more powerful machine learning algorithms, oculomics screening modalities such as optical coherence tomography (OCT), eye tracking, and protein analysis become more effective tools aiding in MS diagnosis. Artificial intelligence can analyse larger and more diverse data sets to potentially discover new parameters of pathology for efficiently diagnosing MS before symptom onset. While there is no known cure for MS, the integration of oculomics with current modalities of diagnosis creates a promising future for developing more sensitive, non-invasive, and cost-effective approaches to MS detection and diagnosis.
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Affiliation(s)
- Alex Suh
- Tulane University School of Medicine, New Orleans, LA, USA.
| | - Gilad Hampel
- Tulane University School of Medicine, New Orleans, LA, USA
| | | | - Joshua Ong
- Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Sharif Amit Kamran
- Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, NV, USA
| | - Ethan Waisberg
- University College Dublin School of Medicine, Belfield, Dublin, Ireland
| | - Phani Paladugu
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Nasif Zaman
- Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, NV, USA
| | - Prithul Sarker
- Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, NV, USA
| | - Alireza Tavakkoli
- Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, NV, USA
| | - Andrew G Lee
- Center for Space Medicine, Baylor College of Medicine, Houston, TX, USA
- Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, Houston, TX, USA
- The Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, USA
- Departments of Ophthalmology, Neurology, and Neurosurgery, Weill Cornell Medicine, New York, NY, USA
- Department of Ophthalmology, University of Texas Medical Branch, Galveston, TX, USA
- University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Texas A&M College of Medicine, Galveston, TX, USA
- Department of Ophthalmology, The University of Iowa Hospitals and Clinics, Iowa City, IA, USA
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2
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Schachar RA, Schachar IH, Kumar S, Feldman EI, Pierscionek BK, Cosman PC. Model of zonular forces on the lens capsule during accommodation. Sci Rep 2024; 14:5896. [PMID: 38467700 PMCID: PMC10928188 DOI: 10.1038/s41598-024-56563-8] [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: 10/04/2023] [Accepted: 03/08/2024] [Indexed: 03/13/2024] Open
Abstract
How the human eye focuses for near; i.e. accommodates, is still being evaluated after more than 165 years. The mechanism of accommodation is essential for understanding the etiology and potential treatments for myopia, glaucoma and presbyopia. Presbyopia affects 100% of the population in the fifth decade of life. The lens is encased in a semi-elastic capsule with attached ligaments called zonules that mediate ciliary muscle forces to alter lens shape. The zonules are attached at the lens capsule equator. The fundamental issue is whether during accommodation all the zonules relax causing the central and peripheral lens surfaces to steepen, or the equatorial zonules are under increased tension while the anterior and posterior zonules relax causing the lens surface to peripherally flatten and centrally steepen while maintaining lens stability. Here we show with a balloon capsule zonular force model that increased equatorial zonular tension with relaxation of the anterior and posterior zonules replicates the topographical changes observed during in vivo rhesus and human accommodation of the lens capsule without lens stroma. The zonular forces required to simulate lens capsule configuration during in vivo accommodation are inconsistent with the general belief that all the zonules relax during accommodation.
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Affiliation(s)
- Ronald A Schachar
- Department of Physics, University of Texas at Arlington, Arlington, TX, USA.
| | - Ira H Schachar
- North Bay Vitreoretinal Consultants, Santa Rosa, CA, USA
| | - Shubham Kumar
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | | | - Barbara K Pierscionek
- Faculty of Health, Medicine and Social Care, Medical Technology Research Centre, Anglia Ruskin University, Chelmsford, UK
| | - Pamela C Cosman
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
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3
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Williams RC, Harrison WW, Carkeet A, Ostrin LA. Twenty-four hour diurnal variation in retinal oxygen saturation. Vision Res 2023; 213:108314. [PMID: 37657366 PMCID: PMC11148934 DOI: 10.1016/j.visres.2023.108314] [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: 05/20/2023] [Revised: 07/12/2023] [Accepted: 08/16/2023] [Indexed: 09/03/2023]
Abstract
Retinal oxygen saturation is influenced by systemic and local vasculature, intraocular pressure (IOP), and individual cellular function. In numerous retinal pathologies, early changes take place at the level of the microvasculature, thereby affecting retinal oxygenation. The purpose of this study was to investigate diurnal variations in retinal oximetry measures and evaluate the relationship with other ocular and systemic physiological processes. Healthy adults (n = 18, mean age 27 ± 5.5 years) participated. Ocular and systemic measures were collected every four hours over 24 h and included retinal oximetry, IOP, optical coherence tomography (OCT), OCT-angiography (OCTA), biometry, blood pressure, and partial pressure of oxygen. Amplitude and acrophase for retinal oxygen saturation, axial length, retinal and choroidal thickness, OCTA parameters, and mean arterial and ocular perfusion pressure (MAP, MOPP) were determined were determined using cosine fits, and multiple regression analysis was performed to compare metrics. Retinal oxygenation saturation demonstrated a significant diurnal variation with an amplitude of 5.84 ± 3.86% and acrophase of 2.35 h. Other parameters that demonstrated significant diurnal variation included IOP, MOPP, axial length, choroidal thickness, superficial vessel density, heart rate, systolic blood pressure, and MAP. Diurnal variations in retinal oxygen saturation were in-phase with choroidal thickness, IOP, and density of the superficial vascular plexus and out-of-phase with axial length and MOPP. In conclusion, retinal oxygenation saturation undergoes diurnal variations over 24 h. These findings contribute to a better understanding of intrinsic and extrinsic factors influencing oxygenation of the area surrounding the fovea.
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Affiliation(s)
- Rachel C Williams
- University of Houston College of Optometry, 4401 Martin Luther King Blvd, Houston, TX 77204, United States
| | - Wendy W Harrison
- University of Houston College of Optometry, 4401 Martin Luther King Blvd, Houston, TX 77204, United States
| | - Andrew Carkeet
- Queensland University of Technology, School of Optometry and Vision Science QUT, Kelvin Grove, Qld 4059, Australia
| | - Lisa A Ostrin
- University of Houston College of Optometry, 4401 Martin Luther King Blvd, Houston, TX 77204, United States.
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4
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Wang F, Yu Z, Xue S, Wang Y, Li L, Wang D, Wang L. Differences Between Angle Configurations in Different Body Positions by Ultrasound Biomicroscopy in Patients with Cortical Age-Related Cataract. Clin Interv Aging 2023; 18:799-808. [PMID: 37215396 PMCID: PMC10199412 DOI: 10.2147/cia.s408798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/10/2023] [Indexed: 05/24/2023] Open
Abstract
Purpose To investigate the differences in parameters related to angle configuration and lens position in patients with cortical age-related cataract by ultrasound biomicroscopy (UBM) in different body positions. Methods Prospective study with 55 patients with cortical age-related cataract proposed for phacoemulsification, examined using a Compact Touch STS UBM (Quantel Medical, France). UBM bag/balloon technology was applied to measure the central anterior chamber depth (ACD) and lens vault (LV) in horizontal and vertical orientation in sitting and supine positions, angle opening distance (AOD500), trabecular iris angle (TIA) and iris lens angle (ILA) in four quadrants: superior, inferior, nasal, and temporal. Results We found no significant difference in ACD between sitting and supine positions (p = 0.053); LV was significantly greater in the supine position (p < 0.001); AOD500 in superior and inferior quadrants were significantly longer in the sitting position (p = 0.001; p < 0.001); TIA in superior and inferior quadrants was significantly greater in the sitting position (p < 0.001; p < 0.001), and TIAmax-min was significantly smaller in the sitting position (p = 0.001); ILA in temporal quadrant was significantly larger in the sitting position (p = 0.015) and ILAmax-min was significantly smaller in the sitting position (p < 0.001). Conclusion The anterior chamber angle was narrower and the lens was positioned more anteriorly in the supine than in the sitting position in cortical age-related cataract. Different positions may affect the angle configuration and the relative space of lens through different directions of mechanics and modes of action.
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Affiliation(s)
- Fenglei Wang
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, People’s Republic of China
| | - Zhiying Yu
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, People’s Republic of China
| | - Shasha Xue
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, People’s Republic of China
| | - Yunxiao Wang
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, People’s Republic of China
| | - Lin Li
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, People’s Republic of China
| | - Dabo Wang
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, People’s Republic of China
| | - Ling Wang
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, People’s Republic of China
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Van Akin MP, Lantz OM, Fellows AM, Toutain-Kidd C, Zegans M, Buckey JC, Anderson AP. Acute effects of postural changes and lower body positive and negative pressure on the eye. Front Physiol 2022; 13:933450. [PMID: 36117718 PMCID: PMC9470749 DOI: 10.3389/fphys.2022.933450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 07/25/2022] [Indexed: 12/02/2022] Open
Abstract
Introduction: Entry into weightlessness results in a fluid shift and a loss of hydrostatic gradients. These factors are believed to affect the eye and contribute to the ocular changes that occur in space. We measured eye parameters during fluid shifts produced by lower body negative pressure (LBNP) and lower body positive pressure (LBPP) and changes in hydrostatic gradient direction (supine-prone) in normal subjects to assess the relative effects of fluid shifts and hydrostatic gradient changes on the eye. Methods: Ocular parameters (intraocular pressure (IOP), ocular geometry, and optical coherence tomography measures) were measured in the seated, supine, and prone positions. To create a fluid shift in the supine and prone positions, the lower body chamber pressure ranged from -40 mmHg to +40 mmHg. Subjects maintained each posture and LBNP/LBPP combination for 15 min prior to data collection. A linear mixed-effects model was used to determine the effects of fluid shifts (as reflected by LBNP/LBPP) and hydrostatic gradient changes (as reflected by the change from seated to supine and from seated to prone) on eye parameters. Results: Chamber pressure was positively correlated with both increased choroidal thickness (β = 0.11 ,p = 0.01) and IOP (β = 0.06 p < 0.001). The change in posture increased IOP compared to seated IOP (supine β = 2.1, p = 0.01, prone β = 9.5, p < 0.001 prone) but not choroidal thickness. IOP changes correlated with axial length (R = 0.72, p < 0.001). Discussion: The effects of hydrostatic gradients and fluids shifts on the eye were investigated by inducing a fluid shift in both the supine and prone postures. Both hydrostatic gradients (posture) and fluid shifts (chamber pressure) affected IOP, but only hydrostatic gradients affected axial length and aqueous depth. Changes in choroidal thickness were only significant for the fluid shifts. Changes in hydrostatic gradients can produce significant changes in both IOP and axial length. Fluid shifts are often cited as important factors in the pathophysiology of SANS, but the local loss of hydrostatic gradients in the head may also play an important role in these ocular findings.
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Affiliation(s)
- M. P. Van Akin
- University of Colorado Boulder, Ann and H.J. Smead Department of Aerospace Engineering Sciences, Boulder, CO, United States
| | - O. M. Lantz
- Geisel School of Medicine at Dartmouth College, Hanover, NH, United States
| | - A. M. Fellows
- Geisel School of Medicine at Dartmouth College, Hanover, NH, United States
| | | | - Michael Zegans
- Geisel School of Medicine at Dartmouth College, Hanover, NH, United States
| | - J. C. Buckey
- Geisel School of Medicine at Dartmouth College, Hanover, NH, United States
| | - A. P. Anderson
- University of Colorado Boulder, Ann and H.J. Smead Department of Aerospace Engineering Sciences, Boulder, CO, United States
- *Correspondence: A. P. Anderson,
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Saehle T. Cerebral Hemodynamics During Exposure to Hypergravity (+G z) or Microgravity (0 G). Aerosp Med Hum Perform 2022; 93:581-592. [DOI: 10.3357/amhp.6008.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND: Optimal human performance and health is dependent on steady blood supply to the brain. Hypergravity (+Gz) may impair cerebral blood flow (CBF), and several investigators have also reported that microgravity (0 G) may influence cerebral hemodynamics. This
has led to concerns for safe performance during acceleration maneuvers in aviation or the impact long-duration spaceflights may have on astronaut health.METHODS: A systematic PEO (Population, Exposure, Outcome) search was done in PubMed and Web of Science, addressing studies on
how elevated +Gz forces or absence of such may impact cerebral hemodynamics. All primary research containing anatomical or physiological data on relevant intracranial parameters were included. Quality of the evidence was analyzed using the GRADE tool.RESULTS: The search
revealed 92 eligible articles. It is evident that impaired CBF during +Gz acceleration remains an important challenge in aviation, but there are significant variations in individual tolerance. The reports on cerebral hemodynamics during weightlessness are inconsistent, but published
data indicate that adaptation to sustained microgravity is also characterized by significant variations among individuals.DISCUSSION: Despite a high number of publications, the quality of evidence is limited due to observational study design, too few included subjects, and methodological
challenges. Clinical consequences of high +Gz exposure are well described, but there are significant gaps in knowledge regarding the intracranial pathophysiology and individual hemodynamic tolerance to both hypergravity and microgravity environments.Saehle T. Cerebral
hemodynamics during exposure to hypergravity (+Gz) or microgravity (0 G). Aerosp Med Hum Perform. 2022; 93(7):581–592.
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7
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Hearon CM, Dias KA, Babu G, Marshall JET, Leidner J, Peters K, Silva E, MacNamara JP, Campain J, Levine BD. Effect of Nightly Lower Body Negative Pressure on Choroid Engorgement in a Model of Spaceflight-Associated Neuro-ocular Syndrome: A Randomized Crossover Trial. JAMA Ophthalmol 2021; 140:59-65. [PMID: 34882176 DOI: 10.1001/jamaophthalmol.2021.5200] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Importance Astronauts returning from long-duration spaceflight experience ocular remodeling related to cephalad fluid shifts induced by microgravity. It is hypothesized that the absence of diurnal reductions in intracranial pressure in microgravity creates a low but persistent pressure gradient at the posterior aspect of the eye, which results in ocular remodeling and space-associated neuro-ocular syndrome (SANS) over many months. Objective To determine whether partial reintroduction of footward fluid shifts during simulated microgravity via lower body negative pressure (LBNP) during sleep attenuates choroid engorgement, an early marker of ocular remodeling related to SANS. Design, Setting, and Participants Between May 2019 and February 2020, participants with no major cardiovascular, kidney, or ophthalmic disease completed 3 days of supine (0°) bed rest with and 3 days without 8 hours of nightly LBNP in a randomized, crossover design. This single-center investigation took place at the UT Southwestern Medical Center. All analyses were conducted blinded to condition and time point. Interventions Eight hours of nightly LBNP (-20 mm Hg) vs no LBNP. Main Outcomes and Measures The primary outcome was the change in choroid area and volume after 3 days of bed rest measured by optical coherence tomography. Results Of 10 participants, 5 were female, the mean (SD) age was 29 (9) years, and the age range was 18 to 55 years. Central venous pressure increased from the seated to supine position (mean [SD], seated: -2.3 [2.0] vs supine: 6.9 [2.0] mm Hg; P < .001), leading to choroid engorgement over 3 days of bed rest (Δ area: +0.09 mm2 [95% CI, 0.04-0.13]; P = .001; Δ volume: +0.37 mm3 [95% CI, 0.19-0.55]; P = .001). Nightly LBNP caused a sustained reduction in supine central venous pressure (mean [SD], 5.7 [2.2] mm Hg to 1.2 [1.4 mm Hg]; P < .001) and attenuated the increase in choroid area (74%) (Δ: 0.02 mm2 [95% -0.02 to 0.06]; P = .01) and volume (53%) (Δ: 0.17 mm3 [95% CI, 0.01-0.34]; P = .05) compared with control. Conclusions and Relevance Nightly LBNP reinstated a footward fluid shift and mitigated the increase in choroid area and volume. LBNP during sleep may be an effective countermeasure for ocular remodeling and SANS during long-duration space missions.
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Affiliation(s)
- Christopher M Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas.,University of Texas Southwestern Medical Center, Dallas
| | - Katrin A Dias
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas.,University of Texas Southwestern Medical Center, Dallas
| | - Gautam Babu
- University of Texas Southwestern Medical Center, Dallas
| | | | - James Leidner
- Internal Medicine, Texas Health Presbyterian Hospital Dallas, Dallas
| | - Kirsten Peters
- University Medical Center, Radboud University, Nijmegen, the Netherlands
| | - Erika Silva
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas
| | - James P MacNamara
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas.,University of Texas Southwestern Medical Center, Dallas
| | | | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas.,University of Texas Southwestern Medical Center, Dallas
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Taibbi G, Young M, Vyas RJ, Murray MC, Lim S, Predovic M, Jacobs NM, Askin KN, Mason SS, Zanello SB, Vizzeri G, Theriot CA, Parsons-Wingerter P. Opposite response of blood vessels in the retina to 6° head-down tilt and long-duration microgravity. NPJ Microgravity 2021; 7:38. [PMID: 34650071 PMCID: PMC8516890 DOI: 10.1038/s41526-021-00165-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 08/19/2021] [Indexed: 01/13/2023] Open
Abstract
The Spaceflight Associated Neuro-ocular Syndrome (SANS), associated with the headward fluid shifts incurred in microgravity during long-duration missions, remains a high-priority health and performance risk for human space exploration. To help characterize the pathophysiology of SANS, NASA's VESsel GENeration Analysis (VESGEN) software was used to map and quantify vascular adaptations in the retina before and after 70 days of bed rest at 6-degree Head-Down Tilt (HDT), a well-studied microgravity analog. Results were compared to the retinal vascular response of astronauts following 6-month missions to the International Space Station (ISS). By mixed effects modeling, the trends of vascular response were opposite. Vascular density decreased significantly in the 16 retinas of eight astronauts and in contrast, increased slightly in the ten retinas of five subjects after HDT (although with limited significance). The one astronaut retina diagnosed with SANS displayed the greatest vascular loss. Results suggest that microgravity is a major variable in the retinal mediation of fluid shifts that is not reproduced in this HDT bed rest model.
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Affiliation(s)
- Giovanni Taibbi
- Department of Ophthalmology and Visual Sciences, The University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | | | - Ruchi J Vyas
- Mori Associates, Ames Research Center, NASA, Moffett Field, Mountain View, CA, USA
| | - Matthew C Murray
- Blue Marble Space Institute of Science, Space Biology Division, Space Technology Mission Directorate, Ames Research Center, NASA, Moffett Field, Mountain View, CA, USA
| | - Shiyin Lim
- Blue Marble Space Institute of Science, Space Biology Division, Space Technology Mission Directorate, Ames Research Center, NASA, Moffett Field, Mountain View, CA, USA
| | - Marina Predovic
- Blue Marble Space Institute of Science, Space Biology Division, Space Technology Mission Directorate, Ames Research Center, NASA, Moffett Field, Mountain View, CA, USA
| | - Nicole M Jacobs
- Blue Marble Space Institute of Science, Space Biology Division, Space Technology Mission Directorate, Ames Research Center, NASA, Moffett Field, Mountain View, CA, USA
| | - Kayleigh N Askin
- National Space Biomedical Research Institute, Ames Research Center, NASA, Moffett Field, Mountain View, CA, USA
| | | | | | - Gianmarco Vizzeri
- Department of Ophthalmology and Visual Sciences, The University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | - Corey A Theriot
- KBR, NASA Johnson Space Center, Houston, TX, USA
- Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, TX, USA
| | - Patricia Parsons-Wingerter
- Low Gravity Exploration Technology, Research and Engineering Directorate, John Glenn Research Center, NASA, Cleveland, OH, USA.
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Mlinar T, Jaki Mekjavic P, Royal JT, Valencic T, Mekjavic IB. Intraocular pressure during handgrip exercise: The effect of posture and hypercapnia in young males. Physiol Rep 2021; 9:e15035. [PMID: 34665531 PMCID: PMC8525324 DOI: 10.14814/phy2.15035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 08/10/2021] [Accepted: 08/22/2021] [Indexed: 11/25/2022] Open
Abstract
PURPOSE As part of our investigations of intraocular pressure (IOP) as a potential contributing factor to the spaceflight-associated neuro-ocular syndrome using the 6° head-down tilt (6°HDT) bed rest experimental model, we compared the effect of rest and isometric exercise in prone and supine 6°HDT positions on IOP with that observed in the seated position. METHODS Ten male volunteers (age = 22.5 ± 3.1 yrs) participated in six interventions. All trials comprised a 10-min rest period, a 3-min isometric handgrip exercise at 30% of participant's maximum, and a 10-min recovery period. The trials were conducted under normocapnic (NCAP) or hypercapnic (FI CO2 = 0.01; HCAP) conditions, the latter mimicking the ambient conditions on the International Space Station. IOP, systolic and diastolic pressures, and heart rate (HR) were measured during the trials. RESULTS Isometric exercise-induced elevations in HR and mean arterial blood pressure. IOP in the prone 6°HDT position was significantly higher (p < 0.001) compared to IOP in supine 6°HDT position and seated trials at all time points. IOP increased with exercise only in a seated HCAP trial (p = 0.042). No difference was observed between trials in NCAP and HCAP. IOP in the prone 6°HDT position was constantly elevated above 21 mmHg, the lower limit for clinical ocular hypertension. CONCLUSIONS IOP in the prone 6°HDT position was similar to IOP reported in astronauts upon entering microgravity, potentially indicating that prone, rather than supine 6°HDT position might be a more suitable experimental analog for investigating the acute ocular changes that occur in microgravity.
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Affiliation(s)
- Tinkara Mlinar
- Department of Automation, Biocybernetics and RoboticsJozef Stefan InstituteLjubljanaSlovenia
- Jozef Stefan International Postgraduate SchoolLjubljanaSlovenia
| | - Polona Jaki Mekjavic
- Department of Automation, Biocybernetics and RoboticsJozef Stefan InstituteLjubljanaSlovenia
- Eye HospitalUniversity Medical CentreLjubljanaSlovenia
- Faculty of MedicineUniversity of LjubljanaLjubljanaSlovenia
| | - Joshua T. Royal
- Department of Automation, Biocybernetics and RoboticsJozef Stefan InstituteLjubljanaSlovenia
- Jozef Stefan International Postgraduate SchoolLjubljanaSlovenia
| | - Tamara Valencic
- Department of Automation, Biocybernetics and RoboticsJozef Stefan InstituteLjubljanaSlovenia
| | - Igor B. Mekjavic
- Department of Automation, Biocybernetics and RoboticsJozef Stefan InstituteLjubljanaSlovenia
- Department of Biomedical Physiology and KinesiologySimon Fraser UniversityBurnabyBritish ColumbiaCanada
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10
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Barosco G, Morbio R, Chemello F, Tosi R, Marchini G. Bilateral angle-closure during hospitalization for coronavirus disease-19 (COVID-19): A case report. Eur J Ophthalmol 2021; 32:NP75-NP82. [PMID: 33885335 PMCID: PMC9111899 DOI: 10.1177/11206721211012197] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Purpose: This report describes a case of bilateral primary angle closure (PAC)
progressing to unilateral end-stage primary angle closure glaucoma (PACG)
associated with treatment for coronavirus disease-19 (COVID-19)
infection. Methods: A 64-year-old man came to our attention because of blurred vision after a
2-month hospital stay for treatment of COVID-19 infection. Examination
findings revealed PACG, with severe visual impairment in the right eye and
PAC in the left eye due to plateau iris syndrome. The patient’s severe
clinical condition and prolonged systemic therapy masked the symptoms and
delayed the diagnosis. Medical chart review disclosed the multifactorial
causes of the visual impairment. Ultrasound biomicroscopy (UBM) aided in
diagnosis and subsequent therapy. Results: The cause behind the primary angle closure and the iridotrabecular contact
was eliminated by bilateral cataract extraction, goniosynechialysis, and
myotic therapy. Conclusions: COVID-19 treatment may pose an increased risk for PAC. Accurate recording of
patient and family ophthalmic history is essential to prevent its onset.
Recognition of early signs of PAC is key to averting its progression to
PACG.
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Affiliation(s)
- Guido Barosco
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, University of Verona, Verona, Italy
| | - Roberta Morbio
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, University of Verona, Verona, Italy
| | - Francesca Chemello
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, University of Verona, Verona, Italy
| | - Roberto Tosi
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, University of Verona, Verona, Italy
| | - Giorgio Marchini
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, University of Verona, Verona, Italy
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Iwasaki KI, Ogawa Y, Kurazumi T, Imaduddin SM, Mukai C, Furukawa S, Yanagida R, Kato T, Konishi T, Shinojima A, Levine BD, Heldt T. Long-duration spaceflight alters estimated intracranial pressure and cerebral blood velocity. J Physiol 2020; 599:1067-1081. [PMID: 33103234 PMCID: PMC7894300 DOI: 10.1113/jp280318] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 10/19/2020] [Indexed: 12/20/2022] Open
Abstract
Key points During long‐duration spaceflights, some astronauts develop structural ocular changes including optic disc oedema that resemble signs of intracranial hypertension. In the present study, intracranial pressure was estimated non‐invasively (nICP) using a model‐based analysis of cerebral blood velocity and arterial blood pressure waveforms in 11 astronauts before and after long‐duration spaceflights. Our results show that group‐averaged estimates of nICP decreased significantly in nine astronauts without optic disc oedema, suggesting that the cephalad fluid shift during long‐duration spaceflight rarely increased postflight intracranial pressure. The results of the two astronauts with optic disc oedema suggest that both increases and decreases in nICP are observed post‐flight in astronauts with ocular alterations, arguing against a primary causal relationship between elevated ICP and spaceflight associated optical changes. Cerebral blood velocity increased independently of nICP and spaceflight‐associated ocular alterations. This increase may be caused by the reduced haemoglobin concentration after long‐duration spaceflight.
Abstract Persistently elevated intracranial pressure (ICP) above upright values is a suspected cause of optic disc oedema in astronauts. However, no systematic studies have evaluated changes in ICP from preflight. Therefore, ICP was estimated non‐invasively before and after spaceflight to test whether ICP would increase after long‐duration spaceflight. Cerebral blood velocity in the middle cerebral artery (MCAv) was obtained by transcranial Doppler sonography and arterial pressure in the radial artery was obtained by tonometry, in the supine and sitting positions before and after 4−12 months of spaceflight in 11 astronauts (10 males and 1 female, 46 ± 7 years old at launch). Non‐invasive ICP (nICP) was computed using a validated model‐based estimation method. Mean MCAv increased significantly after spaceflight (ANOVA, P = 0.007). Haemoglobin decreased significantly after spaceflight (14.6 ± 0.8 to 13.3 ± 0.7 g/dL, P < 0.001). A repeated measures correlation analysis indicated a negative correlation between haemoglobin and mean MCAv (r = −0.589, regression coefficient = −4.68). The nICP did not change significantly after spaceflight in the 11 astronauts. However, nICP decreased significantly by 15% in nine astronauts without optic disc oedema (P < 0.005). Only one astronaut increased nICP to relatively high levels after spaceflight. Contrary to our hypothesis, nICP did not increase after long‐duration spaceflight in the vast majority (>90%) of astronauts, suggesting that the cephalad fluid shift during spaceflight does not systematically or consistently elevate postflight ICP in astronauts. Independently of nICP and ocular alterations, the present results of mean MCAv suggest that long‐duration spaceflight may increase cerebral blood flow, possibly due to reduced haemoglobin concentration. During long‐duration spaceflights, some astronauts develop structural ocular changes including optic disc oedema that resemble signs of intracranial hypertension. In the present study, intracranial pressure was estimated non‐invasively (nICP) using a model‐based analysis of cerebral blood velocity and arterial blood pressure waveforms in 11 astronauts before and after long‐duration spaceflights. Our results show that group‐averaged estimates of nICP decreased significantly in nine astronauts without optic disc oedema, suggesting that the cephalad fluid shift during long‐duration spaceflight rarely increased postflight intracranial pressure. The results of the two astronauts with optic disc oedema suggest that both increases and decreases in nICP are observed post‐flight in astronauts with ocular alterations, arguing against a primary causal relationship between elevated ICP and spaceflight associated optical changes. Cerebral blood velocity increased independently of nICP and spaceflight‐associated ocular alterations. This increase may be caused by the reduced haemoglobin concentration after long‐duration spaceflight.
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Affiliation(s)
- Ken-Ichi Iwasaki
- Department of Social Medicine, Division of Hygiene, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan
| | - Yojiro Ogawa
- Department of Social Medicine, Division of Hygiene, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan
| | - Takuya Kurazumi
- Department of Social Medicine, Division of Hygiene, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan
| | - Syed M Imaduddin
- Department of Electrical Engineering and Computer Science, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Chiaki Mukai
- Space Biomedical Research Group, Japan Aerospace Exploration Agency, Tsukuba-shi, Ibaraki, Japan.,Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Satoshi Furukawa
- Space Biomedical Research Group, Japan Aerospace Exploration Agency, Tsukuba-shi, Ibaraki, Japan
| | - Ryo Yanagida
- Department of Social Medicine, Division of Hygiene, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan
| | - Tomokazu Kato
- Department of Social Medicine, Division of Hygiene, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan
| | - Toru Konishi
- Department of Social Medicine, Division of Hygiene, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan.,Aeromedical Laboratory, Japan Air Self-Defense Force, Ministry of Defense, Sayama-shi, Saitama, Japan
| | - Ari Shinojima
- Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Benjamin D Levine
- The Institute for Exercise and Environmental Medicine (IEEM) at Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.,Department of Medicine and Cardiology, the University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Thomas Heldt
- Department of Electrical Engineering and Computer Science, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
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12
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Lawley JS, Babu G, Janssen SLJE, Petersen LG, Hearon CM, Dias KA, Sarma S, Williams MA, Whitworth LA, Levine BD. Daily generation of a footward fluid shift attenuates ocular changes associated with head-down tilt bed rest. J Appl Physiol (1985) 2020; 129:1220-1231. [PMID: 32940563 DOI: 10.1152/japplphysiol.00250.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Astronauts have presented with a constellation of visual changes referred to as spaceflight-associated neuro-ocular syndrome (SANS). However, neither have early markers of microgravity-induced optic remodeling been fully identified nor have countermeasures been developed. To identify early markers of SANS, we studied 10 subjects with optical coherence tomography and ultrasonography when upright and supine and again after 24 h of 6° head-down tilt (HDT) bed rest. Upon acute transition from the upright to the supine position, choroid area (2.24 ± 0.53 to 2.28 ± 0.52 mm2, P = 0.001) and volume (9.51 ± 2.08 to 9.73 ± 2.08 mm3, P = 0.002) increased. After 24 h of HDT bed rest, subfoveal choroidal thickness (372 ± 93 to 381 ± 95 µm, P = 0.02), choroid area (2.25 ± 0.52 to 2.33 ± 0.54 mm2, P = 0.08), and volume (9.64 ± 2.03 to 9.82 ± 2.08 mm3, P = 0.08) increased relative to the supine position. Subsequently, seven subjects spent 3 days in -6°HDT bed rest to assess whether low-level lower body negative pressure (LBNP) could prevent the observed choroidal engorgement during bed rest. Maintaining the -6° HDT position for 3 days caused choroid area (Δ0.11 mm2, P = 0.05) and volume (Δ0.45 mm3, P = 0.003) to increase. When participants also spent 8 h daily under -20 mmHg LBNP, choroid volume still increased, but substantially (40%) less than in the control trial (Δ0.27 mm3, P = 0.05). Moreover, the increase in choroid area was diminished (Δ0.03 mm2, P = 0.13), indicating that low-level LBNP attenuates the choroid expansion associated with 3 days of -6° HDT bed rest. These data suggest that low-level LBNP may be an effective countermeasure for SANS.NEW & NOTEWORTHY Choroid measurements appear to be sensitive to changes in gravitational gradients, as well as periods of head-down tilt (HDT) bed rest, suggesting that they are potential indicators of early ocular remodeling and could serve to evaluate the efficacy of countermeasures for SANS. Eight hours of lower body negative pressure (LBNP) daily attenuates the choroid expansion associated with 3 days of strict -6° HDT bed rest, indicating that LBNP may be an effective countermeasure for SANS.
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Affiliation(s)
- Justin S Lawley
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas.,University of Texas Southwestern Medical Center, Dallas, Texas.,Division of Physiology, Department of Sports Science, University of Innsbruck, Innsbruck, Austria
| | - Gautam Babu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas.,University of Texas Southwestern Medical Center, Dallas, Texas
| | | | - Lonnie G Petersen
- Department of Orthopedic Surgery, University of California San Diego, California
| | - Christopher M Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas.,University of Texas Southwestern Medical Center, Dallas, Texas
| | - Katrin A Dias
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas.,University of Texas Southwestern Medical Center, Dallas, Texas
| | - Satyam Sarma
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas.,University of Texas Southwestern Medical Center, Dallas, Texas
| | - Michael A Williams
- Department of Neurology, University of Washington School of Medicine, Seattle, Washington.,Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington
| | | | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas.,University of Texas Southwestern Medical Center, Dallas, Texas
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13
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Manabe Y, Sawada A, Yamamoto T. Localization in Glaucomatous Visual Field Loss Vulnerable to Posture-Induced Intraocular Pressure Changes in Open-Angle Glaucoma. Am J Ophthalmol 2020; 213:9-16. [PMID: 31953057 DOI: 10.1016/j.ajo.2020.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 01/04/2020] [Accepted: 01/06/2020] [Indexed: 10/25/2022]
Abstract
PURPOSE To investigate localization in glaucomatous visual field defects that are vulnerable to posture-induced intraocular pressure (IOP) changes. DESIGN Prospective cross-sectional study. METHODS Ninety-three eyes of 93 newly diagnosed cases with normal tension glaucoma were examined. The IOP was measured in both the sitting and lateral decubitus positions with an Icare rebound tonometer. Visual field tests were performed with a Humphrey Field Analyzer with the Central 30-2 program using Swedish Interactive Threshold Algorithm standard strategies. The total deviation (TD) map values of 51 tested points were used for the analysis. A regression analysis was conducted to investigate relationships between TD in each point or cluster and posture-induced IOP changes. A linear mixed-effects model was used to identify factors associated with TD changes in each visual field cluster. Main outcome measures included the relationship between posture-induced IOP changes and localization of visual field defects. RESULTS There were 54 women and 39 men (mean age, 53.4 ± 12.5 years). The mean IOP per Icare rebound tonometer was 15.5 ± 3.2 mm Hg in the sitting position and 18.8 ± 3.1 mm Hg in the lateral decubitus position. The postural IOP difference was 3.3 ± 1.8 mm Hg (P < .001; range, -1.0 to 7.7 mm Hg). There was a significant negative correlation between TD and posture-induced IOP changes in 4 contiguous central points located just above the horizontal meridian. A linear mixed-effects model revealed a significant association between the difference in postural IOP change and decreased TD in the superior paracentral visual field according to multivariate analysis (P = .010). CONCLUSIONS Posture-induced IOP variations have been shown to be associated with glaucomatous superior paracentral visual field defects.
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Affiliation(s)
- Yusuke Manabe
- Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Akira Sawada
- Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan.
| | - Tetsuya Yamamoto
- Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan
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14
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Abstract
Many experiments have documented the response of intraocular pressure (IOP) to postural change. External forces caused by gravitational orientation change produce a dynamic response that is encountered every day during normal activities. Tilting the body at a small downward angle is also relevant to studying the effects of hypogravity (spaceflight), including ocular changes. We examined data from 36 independent datasets from 30 articles on IOP response to postural change, representing a total population of 821 subjects (≥1173 eyes) with widely varying initial and final postures. We confirmed that IOP was well predicted by a simple quantity, namely the hydrostatic pressure at the level of the eye, although the dependence was complex (nonlinear). Our results show that posturally induced IOP change can be explained by hydrostatic forcing plus an autoregulatory contribution that is dependent on hydrostatic effects. This study represents data from thousands of IOP measurements and provides insight for future studies that consider postural change in relation to ocular physiology, intraocular pressure, ocular blood flow and aqueous humor dynamics.
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15
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Mao XW, Nishiyama NC, Byrum SD, Stanbouly S, Jones T, Drew A, Sridharan V, Boerma M, Tackett AJ, Zawieja D, Willey JS, Delp M, Pecaut MJ. Characterization of mouse ocular response to a 35-day spaceflight mission: Evidence of blood-retinal barrier disruption and ocular adaptations. Sci Rep 2019; 9:8215. [PMID: 31160660 PMCID: PMC6547757 DOI: 10.1038/s41598-019-44696-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 05/17/2019] [Indexed: 12/18/2022] Open
Abstract
The health risks associated with spaceflight-induced ocular structural and functional damage has become a recent concern for NASA. The goal of the present study was to characterize the effects of spaceflight and reentry to 1 g on the structure and integrity of the retina and blood-retinal barrier (BRB) in the eye. To investigate possible mechanisms, changes in protein expression profiles were examined in mouse ocular tissue after spaceflight. Ten week old male C57BL/6 mice were launched to the International Space Station (ISS) on Space-X 12 at the Kennedy Space Center (KSC) on August, 2017. After a 35-day mission, mice were returned to Earth alive. Within 38 +/− 4 hours of splashdown, mice were euthanized and ocular tissues were collected for analysis. Ground control (GC) and vivarium control mice were maintained on Earth in flight hardware or normal vivarium cages respectively. Repeated intraocular pressure (IOP) measurements were performed before the flight launch and re-measured before the mice were euthanized after splashdown. IOP was significantly lower in post-flight measurements compared to that of pre-flight (14.4–19.3 mmHg vs 16.3–20.3 mmHg) (p < 0.05) for the left eye. Flight group had significant apoptosis in the retina and retinal vascular endothelial cells compared to control groups (p < 0.05). Immunohistochemical analysis of the retina revealed that an increased expression of aquaporin-4 (AQP-4) in the flight mice compared to controls gave strong indication of disturbance of BRB integrity. There were also a significant increase in the expression of platelet endothelial cell adhesion molecule-1 (PECAM-1) and a decrease in the expression of the BRB-related tight junction protein, Zonula occludens-1 (ZO-1). Proteomic analysis showed that many key proteins and pathways responsible for cell death, cell cycle, immune response, mitochondrial function and metabolic stress were significantly altered in the flight mice compared to ground control animals. These data indicate a complex cellular response that may alter retina structure and BRB integrity following long-term spaceflight.
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Affiliation(s)
- Xiao W Mao
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, 92350, USA.
| | - Nina C Nishiyama
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, 92350, USA
| | - Stephanie D Byrum
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, 72202, USA.,Arkansas Children's Research Institute, Little Rock, AR, USA
| | - Seta Stanbouly
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, 92350, USA
| | - Tamako Jones
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, 92350, USA
| | - Alyson Drew
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, 92350, USA
| | - Vijayalakshmi Sridharan
- Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, 72202, USA
| | - Marjan Boerma
- Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, 72202, USA
| | - Alan J Tackett
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, 72202, USA.,Arkansas Children's Research Institute, Little Rock, AR, USA
| | - David Zawieja
- Department of Medical Physiology, Texas A&M University, College Station, Texas, USA
| | - Jeffrey S Willey
- Department of Radiation Oncology, Wake Forest School of Medicine, Bowman Gray Center, Winston-Salem, NC, 27101, USA
| | - Michael Delp
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Michael J Pecaut
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, 92350, USA
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16
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Buckey JC, Phillips SD, Anderson AP, Chepko AB, Archambault-Leger V, Gui J, Fellows AM. Microgravity-induced ocular changes are related to body weight. Am J Physiol Regul Integr Comp Physiol 2018; 315:R496-R499. [PMID: 29768035 DOI: 10.1152/ajpregu.00086.2018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
On Earth, tissue weight generates compressive forces that press on body structures and act on the walls of vessels throughout the body. In microgravity, tissues no longer have weight, and tissue compressive forces are lost, suggesting that individuals who weigh more may show greater effects from microgravity exposure. One unique effect of long-duration microgravity exposure is spaceflight-associated neuroocular syndrome (SANS), which can present with globe flattening, choroidal folds, optic disk edema, and a hyperopic visual shift. To determine whether weight or other anthropometric measures are related to ocular changes in space, we analyzed data from 45 individual long-duration astronauts (mean age 47, 36 male, 9 female, mean mission duration 165 days) who had pre- and postflight measures of disk edema, choroidal folds, and manifest ocular refraction. The mean preflight weights of astronauts who developed new choroidal folds [78.6 kg with no new folds vs. 88.6 kg with new folds ( F = 6.2, P = 0.02)] and disk edema [79.1 kg with no edema vs. 95 kg with edema ( F = 9.6, P = 0.003)] were significantly greater than those who did not. Chest and waist circumferences were also significantly greater in those who developed folds or edema. The odds of developing disk edema or new choroidal folds were 55% in the highest- and 9% in the lowest-weight quartile. In this cohort, no women developed disk edema or choroidal folds, although women also weighed significantly less than men [62.9 vs. 85.2 kg ( F = 53.2, P < 0.0001)]. Preflight body weight and anthropometric factors may predict microgravity-induced ocular changes.
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Affiliation(s)
- Jay C Buckey
- Geisel School of Medicine at Dartmouth College, Lebanon, New Hampshire
| | | | | | | | | | - Jiang Gui
- Geisel School of Medicine at Dartmouth College, Lebanon, New Hampshire
| | - Abigail M Fellows
- Geisel School of Medicine at Dartmouth College, Lebanon, New Hampshire
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17
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Anderson AP, Butterfield JS, Subramanian PS, Clark TK. Intraocular pressure and cardiovascular alterations investigated in artificial gravity as a countermeasure to spaceflight associated neuro-ocular syndrome. J Appl Physiol (1985) 2018; 125:567-576. [PMID: 29745798 DOI: 10.1152/japplphysiol.00082.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Artificial gravity (AG) has been proposed as a countermeasure to spaceflight-associated neuro-ocular syndrome (SANS). The etiology of SANS is unknown but mimicking gravitational loading through AG may mitigate these negative adaptations. Seventeen subjects (nine men, eight women; 18-32 yr) were analyzed in four experimental conditions: 1) standing, 2) supine, 3) AG with the center of rotation at the eye (AGEC), and 4) AG with 2 Gs at the feet (AG2G). In both AG conditions, subjects were spun to produce 1 G at their center of mass. Data included self-administered intraocular pressure (IOP, Tono-pen AVIA, Depew, NY), heart rate (HR), and mean arterial blood pressure (MAP, Omron Series 10, Omron Healthcare, Kyoto, Japan). Data were analyzed with repeated measures ANOVAs with Tukey-Kramer corrections for multiple pairwise comparisons. IOP was 15.7 ± 1.4 mmHg (mean ± 95% confidence interval) standing, 18.8 ± 1.3 mmHg supine, 18.5 ± 1.7 mmHg in AGEC, and 17.5 ± 1.5 mmHg in AG2G. Postures showed a main effect [F(3,48) = 11.0, P < 0.0005], with standing significantly lower than supine ( P = 0.0009), AGEC ( P = 0.002), and AG2G (0.036). Supine, AGEC, and AG2G were not statistically different. HR and MAP were lower in supine compared with all other postures ( P = 0.002 to P < 0.0005), but there were no differences between standing, AGEC, and AG2G. IOP in supine and standing was consistent with previous studies, but contrary to our hypothesis, remained elevated in both AG conditions. Cardiovascular parameters and hydrostatic gradients determine IOP, which remain unchanged compared with standing. These results suggest additional influence on IOP from previously unconsidered factors. NEW & NOTEWORTHY This is the first study, to the authors' knowledge, to measure intraocular pressure in short-radius centrifuge artificial gravity (AG), which has been proposed as a countermeasure to the spaceflight-associated neuro-ocular syndrome (SANS). If the etiology of SANS is related to intraocular pressure, these results have implications for whether or not short-radius AG can be used to prevent ocular changes relevant to it. Our results indicate this proposed countermeasure merits further investigation.
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Affiliation(s)
- Allison P Anderson
- Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Colorado
| | - Joseph S Butterfield
- Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Colorado.,Department of Integrative Physiology, University of Colorado Boulder, Colorado
| | | | - Torin K Clark
- Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Colorado
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18
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Inanloo SH, Yahyazadeh SR, Rashidi S, Amini E, Nowroozi MR, Ayayti M, Jamshidian H, Nikoobakht MR, Aghamir SMK, Hemmatian O, Momeni SA. Feasibility and Safety of Ultrasonography Guidance and Flank Position during Percutaneous Nephrolithotomy. J Urol 2018; 200:195-201. [PMID: 29477722 DOI: 10.1016/j.juro.2018.02.074] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2018] [Indexed: 12/23/2022]
Abstract
PURPOSE Percutaneous nephrolithotomy is generally performed using fluoroscopy, which is associated with exposure to radiation. Another drawback of fluoroscopic guided percutaneous nephrolithotomy is the prone position, which is not suitable for all patients. In this study we evaluated the feasibility, safety and efficacy of ultrasound guided percutaneous nephrolithotomy with the patient in the flank position. MATERIALS AND METHODS A total of 603 patients with a mean ± SD age of 50.9 ± 13 years were included in this study from December 2010 to July 2016. Access to the collecting system and tract dilation were performed under ultrasound guidance. Perioperative data on the stone-free rate, operative time, length of stay and complication rates were recorded. RESULTS Successful access was achieved in all but 1 patient. Mean operative time was 56.6 ± 6.5 minutes. Complete stone clearance was achieved in 529 patients (87.7%) and Clavien-Dindo grade 3 complications were noted in 17 (2.8%). Blood transfusion was necessary in 43 patients (7.1%). However, bleeding was self-limited in all cases and did not require angioembolization. CONCLUSIONS To our knowledge this is the largest series of ultrasound guided percutaneous nephrolithotomy with the patient in the flank position. Unlike in other studies we used this procedure in all patients irrespective of stone burden, renal anomaly and body habitus. Ultrasound guided percutaneous nephrolithotomy has outcomes comparable to those of conventional percutaneous nephrolithotomy and it is not associated with radiation exposure. Furthermore, anesthesia while in the flank position might be less harmful in some patients, including those with obesity or cardiopulmonary comorbidities.
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Affiliation(s)
- Seyed Hassan Inanloo
- Department of Urology, Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Endourology, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed Reza Yahyazadeh
- Department of Urology, Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Samaneh Rashidi
- Department of Urology, Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Erfan Amini
- Department of Urology, Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Nowroozi
- Department of Urology, Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohsen Ayayti
- Department of Urology, Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Hassan Jamshidian
- Department of Urology, Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | - Omid Hemmatian
- Department of Urology, Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed Ali Momeni
- Department of Urology, Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran
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