scholarly journals A Mechanistic Review of β-Carotene, Lutein, and Zeaxanthin in Eye Health and Disease

Antioxidants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1046
Author(s):  
Fatima Tuj Johra ◽  
Asim Kumar Bepari ◽  
Anika Tabassum Bristy ◽  
Hasan Mahmud Reza

Carotenoids are natural lipid-soluble antioxidants abundantly found as colorful pigments in fruits and vegetables. At least 600 carotenoids occur naturally, although about 20 of them, including β-carotene, α-carotene, lycopene, lutein, zeaxanthin, meso-zeaxanthin, and cryptoxanthin, are detectable in the human blood. They have distinct physiological and pathophysiological functions ranging from fetal development to adult homeostasis. β-carotene is a precursor of vitamin A that essentially functions in many biological processes including vision. The human macula lutea and eye lens are rich in lutein, zeaxanthin, and meso-zeaxanthin, collectively known as macular xanthophylls, which help maintain eye health and prevent ophthalmic diseases. Ocular carotenoids absorb light from the visible region (400–500 nm wavelength), enabling them to protect the retina and lens from potential photochemical damage induced by light exposure. These natural antioxidants also aid in quenching free radicals produced by complex physiological reactions and, consequently, protect the eye from oxidative stress, apoptosis, mitochondrial dysfunction, and inflammation. This review discusses the protective mechanisms of macular xanthophylls in preventing eye diseases such as cataract, age-related macular degeneration, and diabetic retinopathy. Moreover, some preclinical animal studies and some clinical trials are discussed briefly to understand carotenoid safety and efficacy.

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 84
Author(s):  
Rimjhim Agarwal ◽  
Hung T. Hong ◽  
Alice Hayward ◽  
Stephen Harper ◽  
Neena Mitter ◽  
...  

Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries, such as Australia. Lutein and zeaxanthin are the only two carotenoids found in the macular region of the eye. Studies have shown that an intake of 10 mg and 2 mg per day of lutein and zeaxanthin, respectively, can reduce the rate of progression of AMD. The supply of these carotenoids can only be met through dietary sources or supplements, as these compounds cannot be synthesised by humans. Although lutein is relatively abundant in dietary sources, zeaxanthin has limited sources. In this study, eight orange and three red capsicum varieties were analysed for their carotenoid profiles by UHPLC-DAD-APCI-MS. It was observed that the principal carotenoid for seven of the orange varieties was zeaxanthin, and capsanthin for the three red varieties. One orange variety, which had a darker orange hue, had capsanthin and violaxanthin as its principal carotenoids instead of zeaxanthin. Zeaxanthin concentration (the principal carotenoid) in the seven orange varieties varied from 2.6 ± 0.5 mg/100 g to 25.27 ± 9.4 mg/100 FW, suggesting that as little as 7 g of the high-zeaxanthin line could meet the recommended daily dietary intake of 2 mg/person/day.


Antioxidants ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 177 ◽  
Author(s):  
Natalia A. Muraleva ◽  
Oyuna S. Kozhevnikova ◽  
Anzhela Z. Fursova ◽  
Nataliya G. Kolosova

Age-related macular degeneration (AMD) is a major cause of irreversible visual impairment and blindness in developed countries, and the molecular pathogenesis of AMD is poorly understood. Recent studies strongly indicate that amyloid β (Aβ) accumulation —found in the brain and a defining feature of Alzheimer’s disease—also forms in the retina in both Alzheimer’s disease and AMD. The reason why highly neurotoxic proteins of consistently aggregate in the aging retina, and to what extent they contribute to AMD, remains to be fully addressed. Nonetheless, the hypothesis that Aβ is a therapeutic target in AMD is debated. Here, we showed that long-term treatment with SkQ1 (250 nmol/[kg body weight] daily from the age of 1.5 to 22 months) suppressed the development of AMD-like pathology in senescence-accelerated OXYS rats by reducing the level of Aβ and suppressing the activity of mTOR in the retina. Inhibition of mTOR signaling activity, which plays key roles in aging and age-related diseases, can be considered a new mechanism of the prophylactic effect of SkQ1. It seems probable that dietary supplementation with mitochondria-targeted antioxidant SkQ1 can be a good prevention strategy to maintain eye health and possibly a treatment of AMD.


2003 ◽  
Vol 89 (6) ◽  
pp. 787-793 ◽  
Author(s):  
Antonio Pérez-Gálvez ◽  
Hans D. Martin ◽  
Helmut Sies ◽  
Wilhelm Stahl

The intake of a carotenoid-rich diet is epidemiologically related to a lower risk for different chronic disorders like cardiovascular disease, some types of cancer or age-related macular degeneration. Red pepper (Capsicum annuumL.) and its dietary products contain a variety of carotenoids, which may contribute to the carotenoid pattern of human blood and tissues. The objective of the present study was to assess the availability of carotenoids from paprika oleoresin, including zeaxanthin, β-cryptoxanthin, β-carotene and the paprika-specific oxocarotenoids capsanthin and capsorubin. After overnight fasting, the volunteers (n9) ingested a single dose of the paprika oleoresin containing 6·4 mg zeaxanthin, 4·2 mg β-cryptoxanthin, 6·2 mg β-carotene, 35·0 mg capsanthin and 2·0 mg capsorubin. At different time points the carotenoid pattern in the chylomicron fraction was analysed to evaluate carotenoid absorption. From the major carotenoids present in the paprika oleoresin only zeaxanthin, β-cryptoxanthin and β-carotene were detectable in considerable amounts. Although the xanthophylls in paprika oleoresin were mainly present as mono- or di-esters, only free zeaxanthin and β-cryptoxanthin were found in human samples. The bioavailability of the pepper-specific carotenoids capsanthin and capsorubin from paprika oleoresin is very low. However, oleoresin is a suitable source for the provitamin A carotenoids β-carotene and β-cryptoxanthin and the macular pigment zeaxanthin.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Serge Camelo ◽  
Mathilde Latil ◽  
Stanislas Veillet ◽  
Pierre J. Dilda ◽  
René Lafont

Age-related macular degeneration (AMD) is the commonest cause of severe visual loss and blindness in developed countries among individuals aged 60 and older. AMD slowly progresses from early AMD to intermediate AMD (iAMD) and ultimately late-stage AMD. Late AMD encompasses either neovascular AMD (nAMD) or geographic atrophy (GA). nAMD is defined by choroidal neovascularization (CNV) and hemorrhage in the subretinal space at the level of the macula. This induces a rapid visual impairment caused by the death of photoreceptor cells. Intravitreal injection of anti-vascular endothelial growth factor (VEGF) antibodies is the standard treatment of nAMD but adds to the burden of patient care. GA is characterized by slowly expanding photoreceptor, and retinal pigment epithelium (RPE) degeneration patches progressively leading to blindness. There is currently no therapy to cure GA. Late AMD continues to be an unmet medical need representing a major health problem with millions of patients worldwide. Oxidative stress and inflammation are recognized as some of the main risk factors to developing late AMD. The antioxidant formulation AREDS (Age-Related Eye Disease Studies), contains β-carotene, which has been replaced by lutein and zeaxanthin in AREDS2, are given to patients with iAMD but have a limited effect on the incidence of nAMD and GA. Thus, to avoid or slowdown the development of late stages of AMD (nAMD or GA), new therapies targeting iAMD are needed such as crocetin obtained through hydrolysis of crocin, an important component of saffron (Crocus sativus L.), and norbixin derived from bixin extracted from Bixa orellana seeds. We have shown that these apocarotenoids preserved more effectively RPE cells against apoptosis following blue light exposure in the presence of A2E than lutein and zeaxanthin. In this review, we will discuss the potential use of apocarotenoids to slowdown the progression of iAMD, to reduce the incidence of both forms of late AMD.


2019 ◽  
Vol 102 (4) ◽  
pp. 1044-1058 ◽  
Author(s):  
Torsten Bohn

Abstract Carotenoids are typically tetraterpenoid phytochemicals that cannot be synthesized by humans, some of which such as β-carotene can be metabolized into vitamin A. Sufficient carotenoid intake and tissue levels have been associated with several health benefits including the reduction of cardiovascular diseases and some types of cancer and also the amelioration of age-related macular degeneration. Carotenoids and their metabolites have also been related to reduced inflammation and oxidative stress via interacting with transcription factors, such as NF-κB and Nrf-2, as well as with the nuclear receptors retinoic acid receptor/retinoid X receptor, implicated in immune functions and cellular differentiation. Therefore, carotenoids are important for growth and development. They could mark beneficial constituents in infant food formulas and adult nutritionals, the latter typically constituting protein-rich liquid foods targeting meal replacements. Carotenoids may be present by nature (typically below 20 μg/100 mL) or following fortification (up to 200 μg/100 mL), such as for lutein and β-carotene. However, carotenoid bioavailability may be low and variable, especially in low-fat items. Although most infant foods and adult nutritionals are rich in lipids and proteins, facilitating absorption and availability of carotenoids, unfortunately, very little data is available. In addition, carotenoid detection for such lipid-rich matrices may be challenging as a result of low concentrations and matrix effects. This review aims to highlight considerations for carotenoid bioavailability from infant food formula and adult nutritionals as well as summarize detection methods for carotenoids from these items.


2019 ◽  
Vol 20 (11) ◽  
pp. 2744
Author(s):  
Anna Polosa ◽  
Shasha Lv ◽  
Wassila Ait Igrine ◽  
Laura-Alexie Chevrolat ◽  
Hyba Bessaklia ◽  
...  

To unravel the mechanisms behind the higher resistance to light damage of juvenile (JR) versus adult (AR) rats, Sprague Dawley rats were exposed to a bright luminous environment of 10, 000 lux. The light-induced retinopathy (LIR) was assessed with histology, electroretinography and immunohistochemistry (IHC). In JR, 2 days of exposure induced the typical LIR, while >3 days added little LIR. IHC revealed a subtle migration of microglia (Iba1 marker) from the inner to the outer retina after 3 days of exposure in JR contrasting with the stronger reaction seen after 1 day in AR. Similarly, in JR, the Müller cells expressed less intense GFAP, CNTF and FGF2 staining compared to AR. Our results suggest that in JR the degree of retinal damage is not proportional to the duration of light exposure (i.e., dose-independent retinopathy), contrasting with the dose-dependent LIR reported in AR. The immature immune system in JR may explain the delayed and/or weaker inflammatory response compared to AR, a finding that would also point to the devastating contribution of the immune system in generating the LIR phenotype, a claim also advanced to explain the pathophysiology of other retinal degenerative disorders such as Age-related Macular Degeneration, Diabetic Retinopathy and Retinitis Pigmentosa.


2003 ◽  
Vol 73 (2) ◽  
pp. 95-100 ◽  
Author(s):  
Sies ◽  
Stahl

Lycopene, lutein, and zeaxanthin are major carotenoids in human blood and tissues but unlike b-carotene do not contribute to vitamin A supply. These carotenoids are efficient antioxidants quenching singlet molecular oxygen which is formed in photooxidative processes and thus may contribute to the prevention of light-exposed tissue, skin and eyes, from light-induced damage. Increasing lycopene intake by daily consumption of tomato paste over a period of ten weeks provides protection against erythema formation following UV-irradiation. Lycopene and other carotenoids may be used as oral sun protectants and contribute to the maintenance of skin health. The yellow color of the macula lutea is due to the presence of the carotenoid pigments lutein and zeaxanthin. These macula carotenoids are suggested to play a role in protection against light-dependent damage. Filtering of blue light and scavenging of reactive intermediates generated in photooxidation are considered to be the underlying protective mechanisms. Epidemiological studies provide evidence that an increased consumption of lutein is associated with a lowered risk for age-related macular degeneration, a disease with increasing incidence in the elderly.


Author(s):  
Emem G. Abraham ◽  
Emmanuel O. Megbelayin

Background: Vision screening can help discover some problems hitherto unknown to the patient but it is also a fact that many other disease conditions may also be missed during screening depending on the qualification and skill of those carrying out the test and the available instruments for screening. Eye diseases differ from country to country and even within the same country from community to community and knoweledge of the disease pattern in a given environment is critical for planning of appropraite intervention programs.Methods: Free eye health intervention program was carried out and patients were inially screened by optometrists and ophthalmic nurses for cataract, presbyopia and other minor ophthalmic problems. Patients that had other problems including complicated cataract were referred for further consultation with the ophthalmologists in the field..Results: Of the 547 who were further screened by the ophthalmologists in the field 243 (44.4%) were males and 304 (55.6%) were females with male to female ratio of 1: 1.25. The age range was 1-87 years. The mean(SD) age was 51.27years, median 53years, and mode was 60 years. Cataract and its related problem was the commonest condition139(25.4%), followed by glaucoma 78(14.3%). Age related macular degeneration(AMD) was the commonest posterior segment finding 27(4.9%)  while corneal opacity 11(2.0%) was the commonest anterior segment finding and 19(3.5%) were bilaterally blind.Conclusions: The eye health indices of the people as shown by the disease prevalence and the number of those bilaterally blind are still very poor.


Medicina ◽  
2021 ◽  
Vol 57 (10) ◽  
pp. 1059
Author(s):  
Mattia Di Paolo

Background and Objectives: Saffron treatment and photobiomodulation (PBM) are non-invasive therapeutic approaches able to mitigate and stabilize retinal degenerative diseases such as age-related macular degeneration (AMD). Although different, these therapies partially match their modulated pattern of genes. Recent attempts to find an additive effect by coadministration of saffron and PBM have failed. Instead, in this study, a different protocol to increase neuroprotection by providing consecutive saffron and PBM treatment administration is suggested. Materials and Methods: Albino rats, whose retinal damage was caused by light exposure (LD, light damage), were subjected to differential treatment protocols before and after LD: (1) PBM followed by saffron; and (2) single treatments of PBM. Thinning of the photoreceptor layer and neuro-inflammatory markers for gliosis and microglia were assessed via immune-histochemical techniques. Results: Results confirm that PBM and saffron alone cope with retinal neurodegenerative processes, preserving retinal thickness and gliosis and microglia invasion in a differential way. However, the synergistic effect of the combined treatment was restricted to the early neuroinflammation, even when provided sequentially. Conclusion: The broad spectra of action of both neuroprotectants require further investigation to identify other key pathways helpful in enhancing the effects of these two approaches in combination.


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