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Lutein: A Nutraceutical Nanoconjugate for Human Health
Published in Harishkumar Madhyastha, Durgesh Nandini Chauhan, Nanopharmaceuticals in Regenerative Medicine, 2022
Ishani Bhat, Bangera Sheshappa Mamatha
Lutein is an oxygenated xanthophyll carotenoid consisting of nine conjugated double bonds in a C40 isoprenoid with two ionone rings, each bound to a hydroxyl group (OH) at 3 and 3’ positions, at either end of the isoprenoid (Figure 11.1). Zeaxanthin and meso-zeaxanthin are isomers of lutein and all the three compounds share a common molecular formula C40H56O2. Because the three xanthophyll carotenoids are concentrated in the human eye macula (lutein: 36%, zeaxanthin: 18%, and meso-zeaxanthin: 18%), they are collectively called macular pigments (Bone et al., 1993). The chemical configuration of lutein is not only responsible for manifesting major biological activities such as antioxidant and light-absorbing properties but also defines its polarity and solubility (Woodall et al. 1997). These pigments have their peak absorption at 460 nm, which corresponds to the wavelength of “blue light hazard” (400–500 nm). The incident high-energy, short-wavelength visible blue light causes oxidative stress in the eyes. The MP absorbs 40–90% of blue light, which is incidental to the retina. However, this filtering is Macular Pigment concentration-dependent. Thus, macular pigments function as blue light filtering anti-oxidants to protect the retinal pigment epithelial cells in the eyes from the consequences of light-induced oxidative stress (Krinsky et al. 2003). Henceforth, they are positively associated with preventing age-related macular degeneration.
Lifestyle factors
Published in Jane Hanley, Mark Williams, Fathers and Perinatal Mental Health, 2019
There is increasing awareness on the impact of light emitted from televisions screens, phones, tablets and computers. The exposure to this blue light inhibits the production of melatonin which in turn affects the circadian rhythm.
Lutein in Neural Health and Disease
Published in Robert E.C. Wildman, Richard S. Bruno, Handbook of Nutraceuticals and Functional Foods, 2019
As is true of many carotenoids, lutein absorbs light. The particular wavelengths of absorption correspond to approximately 450 nm, or the blue light region. Due to its high energy, blue light can penetrate tissues and cause cellular damage. Blue light is common in the environment and a constituent of the visible light spectrum: sources include sunlight and some forms of artificial lighting. Accordingly, lutein's protective qualities on health of the eye fall into two major categories: (1) absorption or “filtering” of damaging light75 and (2) antioxidant ability.84 Lutein supplementation in healthy term newborns has been shown to increase antioxidant activity and decrease oxidative stress as compared to newborns who did not receive lutein supplementation.85 The selective accumulation of lutein in the retina may also be due to specific properties that afford membrane stability. Properties of lutein that may support membrane integrity include a high membrane solubility, transmembrane orientation, high chemical stability, and location in the most vulnerable regions of photoreceptors.4
Spectrophotometric properties of commercially available blue blockers across multiple lighting conditions
Published in Chronobiology International, 2022
Brooke J. Mason, Andrew S. Tubbs, Fabian-Xosé Fernandez, Michael A. Grandner
Blue light blocking lenses (“blue blockers”) offer a novel approach for managing biologically active light exposure by filtering out short wavelength light. Preliminary data suggest that blue blockers can increase nighttime melatonin secretion in a laboratory setting (Sasseville et al. 2006), improve sleep quality (Shechter et al. 2018), decrease cortisol (Heo et al. 2017), and reduce nighttime arousal (van der Lely et al. 2015). Such lenses may also help shift workers to maintain consistent circadian rhythms by providing control over circadian-proficient light exposure (Aarts et al. 2020; Sasseville and Hébert 2010). Working nights or rotating shifts undermines typical sleep/wake schedules, such that shift workers often report trouble sleeping and are at greater risk of developing a circadian rhythm disorder (Wickwire et al. 2017). Again, these effects are not trivial, as shift work is associated with cancer (Yuan et al. 2019), cardiometabolic disease (Proper et al. 2016; Puttonen et al. 2011; Sookoian et al. 2007), and cognitive impairment (Weinmann et al. 2018). By comparison, blue locking lenses are a simple and affordable intervention that may prevent some of these effects.
Modelling the effect of light through commercially available blue-blocking lenses on the human circadian system
Published in Clinical and Experimental Optometry, 2022
Hind Saeed Alzahrani, Sieu K Khuu, Maitreyee Roy
Short-wavelength blue light is strongly related to the suppression of the hormone melatonin secreted by the pineal gland typically at night and essential to maintaining a normal sleep-wake circadian rhythm. The action spectrum of nocturnal melatonin suppression has been used as an indicator of the spectral sensitivity of the circadian system, which has peak wavelengths of between 446 nm and 483 nm.5,6 Previous studies have shown that monochromatic short-wavelength light and blue-enriched polychromatic light are more effective than light at longer wavelengths at influencing melatonin production,5,6 and resetting the circadian phase.7 Indeed, light exposure in the evening hours to short-wavelength (blue) light produced by lamps and electronic devices at any intensity level, can cause a delay and reduction in the amount of melatonin secretion, reducing the feeling of sleep and the duration of rapid eye movement (REM) sleep.8,9
Safety and Long-term Scleral Biomechanical Stability of Rhesus Eyes after Scleral Cross-linking by Blue Light
Published in Current Eye Research, 2021
Yu Li, Fengju Zhang, Mingshen Sun, Lingbo Lai, Xiaotong Lv, Chong Liu, Mengmeng Wang, Ningli Wang
Retinal protection against oxidative damage occurs mainly through blue light absorption, the quenching of excited triplet states of photosensitizers, and the physical quenching of singlet oxygen.28 However, these processes are exactly the opposite of those occurring during cross-linking. Blue light has been widely used to model retinal degeneration by leading to photoreceptor cell death.29,30 Blue light may cause retinal photoreceptor cell damage.31 After 2 h of blue light irradiation, the a and b ERG amplitudes in mice decreased, and some cell fragments were found in the outer nuclear layer.32 Another experimental study showed that the treated rabbit retina became more disordered in the inner and outer segments of the photoreceptor cells compared with the control rabbit retina after 24 h of blue light irradiation; the more disordered the cell arrangement, the thinner the retina.33 All of these results indicate that blue light induces retinal oxidative stress injury. The scleral thickness of rhesus monkeys is very thin, at approximately 0.295 mm. Blue light with greater penetration ability5 may penetrate through the sclera and radiate directly to the retina, inducing retinal injury.