1
|
Denton ML, Clark CD, Noojin GD, West H, Stadick A, Khan T. Unified modeling of photothermal and photochemical damage. FRONTIERS IN OPHTHALMOLOGY 2024; 4:1408869. [PMID: 39224466 PMCID: PMC11366703 DOI: 10.3389/fopht.2024.1408869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 07/19/2024] [Indexed: 09/04/2024]
Abstract
Correlating damage outcomes to a retinal laser exposure is critical for diagnosis and choosing appropriate treatment modalities. Therefore, it is important to understand the causal relationships between laser parameters, such as wavelength, power density, and length of exposure, and any resulting injury. Differentiating photothermal from photochemical processes in an in vitro retinal model using cultured retinal pigment epithelial cells would be a first step in achieving this goal. The first-order rate constant of Arrhenius has been used for decades to approximate cellular thermal damage. A modification of this equation, called the damage integral (Ω), has been used extensively to predict the accumulation of laser damage from photothermal inactivation of critical cellular proteins. Damage from photochemical processes is less well studied and most models have not been verified because they require quantification of one or more uncharacterized chemical species. Additionally, few reports on photochemical damage report temperature history, measured or simulated. We used simulated threshold temperatures from a previous in vitro study to distinguish between photothermal and photochemical processes. Assuming purely photochemical processes also inactivate critical cellular proteins, we report the use of a photothermal Ω and a photochemical Ω that work in tandem to indicate overall damage accumulation. The combined damage integral (ΩCDI) applies a mathematical switch designed to describe photochemical damage relative to wavelength and rate of photon delivery. Although only tested in an in vitro model, this approach may transition to predict damage at the mammalian retina.
Collapse
Affiliation(s)
- Michael L. Denton
- Bioeffects Division, Air Force Research Lab, JBSA-Fort Sam Houston, TX, United States
| | - Clifton D. Clark
- Department of Physics, Fort Hays State University, Hays, KS, United States
- Biosciences Department, Science Applications International Corporation, JBSA-Fort Sam Houston, TX, United States
| | - Gary D. Noojin
- Bioeffects Division, Air Force Research Lab, JBSA-Fort Sam Houston, TX, United States
| | - Haleigh West
- Biosciences Department, Science Applications International Corporation, JBSA-Fort Sam Houston, TX, United States
- Department of Mathematics and Statistics, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Allison Stadick
- Biosciences Department, Science Applications International Corporation, JBSA-Fort Sam Houston, TX, United States
- Department of Chemistry, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Taufiquar Khan
- Department of Mathematics and Statistics, University of North Carolina at Charlotte, Charlotte, NC, United States
| |
Collapse
|
2
|
Álvarez-Barrios A, Álvarez L, García M, Artime E, Pereiro R, González-Iglesias H. Antioxidant Defenses in the Human Eye: A Focus on Metallothioneins. Antioxidants (Basel) 2021; 10:89. [PMID: 33440661 PMCID: PMC7826537 DOI: 10.3390/antiox10010089] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/03/2021] [Accepted: 01/04/2021] [Indexed: 12/12/2022] Open
Abstract
The human eye, the highly specialized organ of vision, is greatly influenced by oxidants of endogenous and exogenous origin. Oxidative stress affects all structures of the human eye with special emphasis on the ocular surface, the lens, the retina and its retinal pigment epithelium, which are considered natural barriers of antioxidant protection, contributing to the onset and/or progression of eye diseases. These ocular structures contain a complex antioxidant defense system slightly different along the eye depending on cell tissue. In addition to widely studied enzymatic antioxidants, including superoxide dismutase, glutathione peroxidase, catalase, peroxiredoxins and selenoproteins, inter alia, metallothioneins (MTs) are considered antioxidant proteins of growing interest with further cell-mediated functions. This family of cysteine rich and low molecular mass proteins captures and neutralizes free radicals in a redox-dependent mechanism involving zinc binding and release. The state of the art of MTs, including the isoforms classification, the main functions described to date, the Zn-MT redox cycle as antioxidant defense system, and the antioxidant activity of Zn-MTs in the ocular surface, lens, retina and its retinal pigment epithelium, dependent on the number of occupied zinc-binding sites, will be comprehensively reviewed.
Collapse
Affiliation(s)
- Ana Álvarez-Barrios
- Instituto Universitario Fernández-Vega (Fundación de Investigación Oftalmológica, Universidad de Oviedo), 33012 Oviedo, Spain; (A.Á.-B.); (L.Á.); (M.G.); (E.A.); (R.P.)
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julián Clavería, 8, 33006 Oviedo, Spain
| | - Lydia Álvarez
- Instituto Universitario Fernández-Vega (Fundación de Investigación Oftalmológica, Universidad de Oviedo), 33012 Oviedo, Spain; (A.Á.-B.); (L.Á.); (M.G.); (E.A.); (R.P.)
| | - Montserrat García
- Instituto Universitario Fernández-Vega (Fundación de Investigación Oftalmológica, Universidad de Oviedo), 33012 Oviedo, Spain; (A.Á.-B.); (L.Á.); (M.G.); (E.A.); (R.P.)
- Instituto Oftalmológico Fernández-Vega, Avda. Dres. Fernández-Vega, 34, 33012 Oviedo, Spain
| | - Enol Artime
- Instituto Universitario Fernández-Vega (Fundación de Investigación Oftalmológica, Universidad de Oviedo), 33012 Oviedo, Spain; (A.Á.-B.); (L.Á.); (M.G.); (E.A.); (R.P.)
| | - Rosario Pereiro
- Instituto Universitario Fernández-Vega (Fundación de Investigación Oftalmológica, Universidad de Oviedo), 33012 Oviedo, Spain; (A.Á.-B.); (L.Á.); (M.G.); (E.A.); (R.P.)
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julián Clavería, 8, 33006 Oviedo, Spain
| | - Héctor González-Iglesias
- Instituto Universitario Fernández-Vega (Fundación de Investigación Oftalmológica, Universidad de Oviedo), 33012 Oviedo, Spain; (A.Á.-B.); (L.Á.); (M.G.); (E.A.); (R.P.)
- Instituto Oftalmológico Fernández-Vega, Avda. Dres. Fernández-Vega, 34, 33012 Oviedo, Spain
| |
Collapse
|
3
|
Aryan N, Betts-Obregon BS, Perry G, Tsin AT. Oxidative Stress Induces Senescence in Cultured RPE Cells. Open Neurol J 2016; 10:83-7. [PMID: 27651846 PMCID: PMC5012081 DOI: 10.2174/1874205x01610010083] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 07/25/2016] [Accepted: 07/27/2016] [Indexed: 11/22/2022] Open
Abstract
The aim of this research is to determine whether oxidative stress induces cellular senescence in human retinal pigment epithelial cells. Cultured ARPE19 cells were subjected to different concentrations of hydrogen peroxide to induce oxidative stress. Cells were seeded into 24-well plates with hydrogen peroxide added to cell medium and incubated at 37°C + 5% CO2 for a 90-minute period [at 0, 300, 400 and 800 micromolar (MCM) hydrogen peroxide]. The number of viable ARPE19 cells were recorded using the Trypan Blue Dye Exclusion Method and cell senescence was measured by positive staining for senescence-associated beta-galactosidase (SA-beta-Gal) protein. Without hydrogen peroxide treatment, the number of viable ARPE19 cells increased significantly from 50,000 cells/well to 197,000 within 72 hours. Treatment with hydrogen peroxide reduced this level of cell proliferation significantly (to 52,167 cells at 400 MCM; to 49,263 cells at 800 MCM). Meanwhile, cells with a high level of positive senescence-indicator SA-Beta-Gal-positive staining was induced by hydrogen peroxide treatment (from a baseline level of 12% to 80% at 400 MCM and at 800 MCM). Our data suggests that oxidative stress from hydrogen peroxide treatment inhibited ARPE19 cell proliferation and induced cellular senescence.
Collapse
Affiliation(s)
- Nona Aryan
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | | | - George Perry
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Andrew T. Tsin
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, 78249, USA
| |
Collapse
|
4
|
Lorach H, Kung J, Beier C, Mandel Y, Dalal R, Huie P, Wang J, Lee S, Sher A, Jones BW, Palanker D. Development of Animal Models of Local Retinal Degeneration. Invest Ophthalmol Vis Sci 2015. [PMID: 26207299 DOI: 10.1167/iovs.14-16011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
PURPOSE Development of nongenetic animal models of local retinal degeneration is essential for studies of retinal pathologies, such as chronic retinal detachment or age-related macular degeneration. We present two different methods to induce a highly localized retinal degeneration with precise onset time, that can be applied to a broad range of species in laboratory use. METHODS A 30-μm thin polymer sheet was implanted subretinally in wild-type (WT) rats. The effects of chronic retinal separation from the RPE were studied using histology and immunohistochemistry. Another approach is applicable to species with avascular retina, such as rabbits, where the photoreceptors and RPE were thermally ablated over large areas, using a high power scanning laser. RESULTS Photoreceptors above the subretinal implant in rats degenerated over time, with 80% of the outer nuclear layer disappearing within a month, and the rest by 3 months. Similar loss was obtained by selective photocoagulation with a scanning laser. Cells in the inner nuclear layer and ganglion cell layer were preserved in both cases. However, there were signs of rewiring and decrease in the size of the bipolar cell terminals in the damaged areas. CONCLUSIONS Both methods induce highly reproducible degeneration of photoreceptors over a defined area, with complete preservation of the inner retinal neurons during the 3-month follow-up. They provide a reliable platform for studies of local retinal degeneration and development of therapeutic strategies in a wide variety of species.
Collapse
Affiliation(s)
- Henri Lorach
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 2Department of Ophthalmology, Stanford University, Stanford, California, United States 3Institut de la Vision, Paris, France
| | - Jennifer Kung
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Corinne Beier
- Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, California, United States
| | - Yossi Mandel
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 5Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Philip Huie
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 2Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Jenny Wang
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 2Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Seungjun Lee
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Alexander Sher
- Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, California, United States
| | - Bryan William Jones
- Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 2Department of Ophthalmology, Stanford University, Stanford, California, United States
| |
Collapse
|
5
|
Abstract
OBJECTIVE This overview of ultraviolet (UV) phototoxicity considers the interaction of UVA and short-wavelength VIS light with the retina and retinal pigment epithelium. METHODS The damage mechanisms underlying UV retinal phototoxicity are illustrated with a literature survey and presentation of experimental results. RESULTS Depending on the wavelength and exposure duration, light interacts with tissue by three general mechanisms: thermal, mechanical, or photochemical. Although the anterior structures of the eye absorb much of the UV component of the optical radiation spectrum, a portion of the UVA band (315-400 nm) penetrates into the retina. Natural sources, such as the sun, emit energetic UV photons in relatively long durations, which typically do not result in energy confinement in the retina, and thus do not produce thermal or mechanical damage but are capable of inducing photochemical damage. Photochemical damage in the retina proceeds through Type 1 (direct reactions involving proton or electron transfers) and Type 2 (reactions involving reactive oxygen species) mechanisms. Commonly used drugs, such as certain antibiotics, nonsteroidal anti-inflammatory drugs, psychotherapeutic agents, and even herbal medicines, may act as photosensitizers that promote retinal UV damage, if they are excited by UVA or visible light and have sufficient retinal penetration. CONCLUSIONS Although the anterior portion of the eye is the most susceptible to UV damage, the retina is at risk to the longer UV wavelengths that propagate through the ocular media. Some phototoxicity may be counteracted or reduced by dietary intake of antioxidants and protective phytonutrients.
Collapse
|
6
|
Lee JK, Kim HY, Cho HK. Retinal Changes in White Rabbits after Exposure to the Light of an Operating Microscope. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2011. [DOI: 10.3341/jkos.2011.52.5.603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Jeong Kyu Lee
- Department of Ophthalmology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Ho Young Kim
- Department of Ophthalmology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Ho Kyun Cho
- Department of Ophthalmology, Chung-Ang University College of Medicine, Seoul, Korea
| |
Collapse
|
7
|
Mohan S, Koyoma K, Thangasamy A, Nakano H, Glickman RD, Mohan N. Low shear stress preferentially enhances IKK activity through selective sources of ROS for persistent activation of NF-kappaB in endothelial cells. Am J Physiol Cell Physiol 2007; 292:C362-71. [PMID: 16914532 DOI: 10.1152/ajpcell.00535.2005] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
NF-kappaB signaling pathway has been known to play a major role in the pathological process of atherogenesis. Unlike high shear stress, in which the NF-kappaB activity is transient, our earlier studies have demonstrated a persistent activation of NF-kappaB in response to low shear stress in human aortic endothelial cells. These findings partially explained why low shear regions that exist at bifurcations of arteries are prone to atherosclerosis, unlike the relatively atheroprotective high shear regions. In the present study, we further investigated 1) the role of NF-kappaB signaling kinases (IKKalpha and beta) that may be responsible for the sustained activation of NF-kappaB in low shear stress and 2) the regulation of these kinases by reactive oxygen species (ROS). Our results demonstrate that not only is a significant proportion of low shear-induced-kinase activity is contributed by IKKbeta, but it is also persistently induced for a prolonged time frame. The IKK activity (both alpha and beta) is blocked by apocynin (400 microM), a specific NADPH oxidase inhibitor, and diphenyleneiodonium chloride (DPI; 10 microM), an inhibitor of flavin-containing oxidases like NADPH oxidases. Determination of ROS also demonstrated an increased generation in low shear stress that could be blocked by DPI. These results suggest that the source of ROS generation in endothelial cells in response to low shear stress is NADPH oxidase. The DPI-inhibitable component of ROS is the primary regulator of specific upstream kinases that determine the persistent NF-kappaB activation selectively in low shear-induced endothelial cells.
Collapse
Affiliation(s)
- Sumathy Mohan
- Department of Pathology, University of Texas Health Science Center, San Antonio, TX 78229, USA.
| | | | | | | | | | | |
Collapse
|
8
|
Abstract
Light damage to the retina occurs through three general mechanisms involving thermal, mechanical, or photochemical effects. The particular mechanism activated depends on the wavelength and exposure duration of the injuring light. The transitions between the various light damage mechanism may overlap to some extent. Energy confinement is a key concept in understanding or predicting the type of damage mechanism produced by a given light exposure. As light energy (either from a laser or an incoherent source) is deposited in the retina, its penetration through, and its absorption in, various tissue compartments is determined by its wavelength. Strongly absorbing tissue components will tend to "concentrate" the light energy. The effect of absorbed light energy largely depends on the rate of energy deposition, which is correlated with the exposure duration. If the rate of energy deposition is too low to produce an appreciable temperature increase in the tissue, then any resulting tissue damage necessarily occurs because of chemical (oxidative) reactions induced by absorption of energetic photons (photochemical damage). If the rate of energy deposition is faster than the rate of thermal diffusion (thermal confinement), then the temperature of the exposed tissue rises. If a critical temperature is reached (typically about 10 degrees C above basal), then thermal damage occurs. If the light energy is deposited faster than mechanical relaxation can occur (stress confinement), then a thermoelastic pressure wave is produced, and tissue is disrupted by shear forces or by cavitation-nonlinear effects. Very recent evidence suggests that ultrashort laser pulses can produce tissue damage through nonlinear and photochemical mechanisms; the latter because of two-photon excitation of cellular chromophores. In addition to tissue damage caused directly by light absorption, light toxicity can be produced by the presence of photosensitizing agents. Drugs excited to reactive states by ultraviolet (UV) or visible light produce damage by type I (free radical) and type II (oxygen dependent) mechanisms. Some commonly used drugs, such as certain antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and psychotherapeutic agents, as well as some popular herbal medicines, can produce ocular phototoxicity. Specific cellular effects and damage end points characteristic of light damage mechanisms are described.
Collapse
Affiliation(s)
- Randolph D Glickman
- Department of Ophthalmology, University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA.
| |
Collapse
|
9
|
Godley BF, Jin GF, Guo YS, Hurst JS. Bcl-2 overexpression increases survival in human retinal pigment epithelial cells exposed to H(2)O(2). Exp Eye Res 2002; 74:663-9. [PMID: 12126940 DOI: 10.1006/exer.2001.1146] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The integrity of the retinal pigment epithelium, especially that of the macula is essential for the preservation of vision into old age. The chronic exposure to sunlight and peroxidized lipids from phagocytized photoreceptor outer segments imposes a high level of oxidative stress on the retinal tissues, which increases with age as antioxidant protection declines and therefore could accelerate apoptosis. Bcl-2 known to facilitate mitochondrial DNA repair and cellular survival in other tissues was overexpressed in a single clone of human retinal pigment epithelium cells after stable transfection with humanbcl-2 in rhoSFV-neoexpression factor. Near confluent cells (2nd-4th generation permanently bcl-2 transfected) were protected from mitochondrial dysfunction after exposure to H(2)O(2) up to 150 microM. With 200 microM H(2)O(2), function in transfected cells declined by only 25% control activity as determined by MTT reduction assays, compared to wild type and vector only transfected cells expressing normal bcl-2 levels. Similarly the bcl-2 -transfected cells were more resistant to mitochondrial DNA damage after H(2)O(2) treatment than the other groups and suffered 50% less damage after exposure to 200 microM H(2)O(2), as assayed by quantitative polymerase chain reaction assays. These data suggest that bcl-2 overexpression protects human RPE cells from mitochondrial respiratory dysfuction, mitochondrial DNA damage and promotes cellular survival in response to oxidative stress induced by H(2)O(2).
Collapse
|