Low-Luminance Blue Light-Enhanced Phototoxicity in A2E-Laden RPE Cell Cultures and Rats

Lin, Cheng Hui; Wu, Man; Huang, Wei; Chow, Diana Shu Lian; Hsiao, George; Cheng, Yu Wen

doi:10.3390/ijms20071799

Cited by 28 publications

(33 citation statements)

References 47 publications

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“…Especially blue light, with wavelengths ranging from 380 to 500 nm, has a high potential to induce retinal damage because of its higher energy per photon than longer wavelength lights. In the retina, blue light is absorbed by lipofuscin in the retinal pigment epithelial (RPE) layer, rhodopsin in the photoreceptor layer, and other chromophores [3][4][5] and singlet oxygen and other radical species that damage the RPE and photoreceptors are produced [6]. These photochemical or photooxidative light-tissue reactions occur with low and sustained irradiation under the threshold value that induces thermal changes [1,3,7].…”

Section: Introductionmentioning

confidence: 99%

Macular pigment changes after cataract surgery with yellow-tinted intraocular lens implantation

2021

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Purpose We previously reported that macular pigment optical density (MPOD) levels decreased during a long follow-up period after clear intraocular lens (IOL) implant surgery presumably due to excessive light exposure. We examined changes in MPOD levels in the eyes that received yellow-tinted IOL implant surgery. Subjects and methods This was a prospective, observational study. Fifty-five eyes of 35 patients were studied. MPOD levels were measured with a dual-wavelength autofluorescence technique on day 4; months 1, 3, and 6; and years 1 and 2 postoperatively. The average optical densities at 0°- 2° eccentricities (local MPODs) and total volumes of MPOD (MPOVs) in the area within 1.5° and 9° eccentricities were analyzed. Results The mean local MPOD at baseline (on day 4) was 0.79 at 0°, 0.71 at 0.5°, 0.68 at 0.9°, and 0.32 at 2°. The mean MPOV within 1.5° and 9° at baseline was 2950 and 18,897, respectively. Local MPOD at 0.9° and 2° and MPOVs were slightly decreased at month 1 and increased after that. The increase reached statistical significance in local MPOD at 0.5° and 2° and MPOVs (Tukey–Kramer test). The changes in MPOV within 9° at year 2 [(MPOV on year 2 − MPOV on day 4) / MPOV on day 4] were from −0.21 to 1.18 (mean and standard deviation: 1.14 ± 0.28). The MPOV of 15 eyes increased more than 10% from the initial value, was maintained within 10% in 21 eyes, and deteriorated more than 10% in only 3 eyes. Conclusions Local MPOD and MPOV tended to slightly decrease month 1 postoperatively and gradually increased after that, but the rates of increases in MPOD levels were small. Yellow-tinted IOLs that have a lower transmittance of blue light might be preferable for preserving MPOD levels after surgery.

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Section: Introductionmentioning

confidence: 99%

Macular pigment changes after cataract surgery with yellow-tinted intraocular lens implantation

2021

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“…In this study, VEGF levels decreased in the RD group and did not statistically change with the addition of BCX. However, blue light is known to trigger inflammatory and angiogenic gene expressions in the early stages and has been reported to increase vascular endothelial growth factor (VEGF) secretion in A2E-loaded RPE cells [ 45 ]. In our study, if exposure to LED light was prolonged, BCX efficacy at these levels would be more noticeable as a ROS scavenger [ 46 , 47 ].…”

Section: Discussionmentioning

confidence: 99%

Different Doses of β‐Cryptoxanthin May Secure the Retina from Photooxidative Injury Resulted from Common LED Sources

Orhan

Tuzcu

Gençoğlu

et al. 2021

Oxidative Medicine and Cellular Longevity

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Retinal damage associated with loss of photoreceptors is a hallmark of eye diseases such as age-related macular degeneration (AMD) and diabetic retinopathy. Potent nutritional antioxidants were previously shown to abate the degenerative process in AMD. β-Cryptoxanthin (BCX) is an essential dietary carotenoid with antioxidant, anti-inflammatory, and provitamin A activity. It is a potential candidate for developing intervention strategies to delay the development/progression of AMD. In the current study, the effect of a novel, highly purified BCX oral formulation on the rat retinal damage model was evaluated. Rats were fed with BCX for four weeks at the doses of 2 and 4 mg/kg body weight in the form of highly bioavailable oil suspension, followed by retinal damage by exposing to the bright light-emitting diode (LED) light (750 lux) for 48 hrs. Animals were sacrificed after 48 hours, and eyes and blood samples were collected and analyzed. BCX supplementations (2 and 4 mg/kg) showed improvements in the visual condition as demonstrated by histopathology of the retina and measured parameters such as total retinal thickness and outer nuclear layer thickness. BCX supplementation helped reduce the burden of oxidative stress as seen by decreased serum and retinal tissue levels of malondialdehyde (MDA) and restored the antioxidant enzyme activities in BCX groups. Further, BCX supplementation modulated inflammatory markers (IL-1β, IL-6, and NF-κB), apoptotic proteins (Bax, Bcl-2, caspase 3), growth proteins and factors (GAP43, VEGF), glial and neuronal proteins (GFAP, NCAM), and heme oxygenase-1 (HO-1), along with the mitochondrial stress markers (ATF4, ATF6, Grp78, Grp94) in the rat retinal tissue. This study indicates that oral supplementation of BCX exerts a protective effect on light-induced retinal damage in the rats via reducing oxidative stress and inflammation, also protected against mitochondrial DNA damage and cellular death.

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“…Lipofuscin is an undegradable lipid–protein aggregate that accumulates in RPE cells as an organism ages. In RPE cells, the major component of lipofuscin is the pyridinium bisretinoid A2E, a photo-inducible reactive oxygen species (ROS) generator [ 3 , 4 ]. A2E intracellular accumulation enhances RPE photosensitization, generating high levels of both hydrogen peroxide (H 2 O 2 ) and superoxide anion (O 2 • − ) when the cells are exposed to blue-violet light, providing a possible cellular mechanism to explain the RPE dysfunction that causes AMD [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

Superior Properties of N-Acetylcysteine Ethyl Ester over N-Acetyl Cysteine to Prevent Retinal Pigment Epithelial Cells Oxidative Damage

Tosi

Giustarini

Franci

et al. 2021

IJMS

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Oxidative stress plays a key role in the pathophysiology of retinal diseases, including age-related macular degeneration (AMD) and diabetic retinopathy, which are the major causes of irreversible blindness in developed countries. An excess of reactive oxygen species (ROS) can directly cause functional and morphological impairments in retinal pigment epithelium (RPE), endothelial cells, and retinal ganglion cells. Antioxidants may represent a preventive/therapeutic strategy and reduce the risk of progression of AMD. Among antioxidants, N-acetyl-L-cysteine (NAC) is widely studied and has been proposed to have therapeutic benefit in treating AMD by mitigating oxidative damage in RPE. Here, we demonstrate that N-acetyl-L-cysteine ethyl ester (NACET), a lipophilic cell-permeable cysteine derivative, increases the viability in oxidative stressed RPE cells more efficiently than NAC by reacting directly and more rapidly with oxidizing agents, and that NACET, but not NAC, pretreatment predisposes RPE cells to oxidative stress resistance and increases the intracellular reduced glutathione (GSH) pool available to act as natural antioxidant defense. Moreover, we demonstrate the ability of NACET to increase GSH levels in rats’ eyes after oral administration. In conclusion, even if experiments in AMD animal models are still needed, our data suggest that NACET may play an important role in preventing and treating retinal diseases associated with oxidative stress, and may represent a valid and more efficient alternative to NAC in therapeutic protocols in which NAC has already shown promising results.

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Low-Luminance Blue Light-Enhanced Phototoxicity in A2E-Laden RPE Cell Cultures and Rats

Cited by 28 publications

References 47 publications

Macular pigment changes after cataract surgery with yellow-tinted intraocular lens implantation

Macular pigment changes after cataract surgery with yellow-tinted intraocular lens implantation

Different Doses of β‐Cryptoxanthin May Secure the Retina from Photooxidative Injury Resulted from Common LED Sources

Superior Properties of N-Acetylcysteine Ethyl Ester over N-Acetyl Cysteine to Prevent Retinal Pigment Epithelial Cells Oxidative Damage

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