Ultrastructural changes in the melanocytes of aging human choroid

Nag, Tapas Chandra

doi:10.1016/j.micron.2015.08.001

Cited by 13 publications

(10 citation statements)

References 33 publications

(29 reference statements)

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“…Regarding macrophages, recent studies reported that macrophages are also involved in the process of lipofuscin accumulation [54], [55], [56]. For example, Luhmannet et al (2009) [55] showed that the accumulation of macrophages with lipofuscin granules in the subretinal space is a normal age-related process that is accelerated in Ccl2−/− mice that show phenotypic features similar to age-related macular degeneration, while Nag (2015) [56] reported macrophages with abundant irregular lipofuscin loaded-melanosomes of variable size in the aging human choroid, suggesting that damaged melanocytes are cleared by these phagocytes.…”

Section: Discussionmentioning

confidence: 99%

“…For example, Luhmannet et al (2009) [55] showed that the accumulation of macrophages with lipofuscin granules in the subretinal space is a normal age-related process that is accelerated in Ccl2−/− mice that show phenotypic features similar to age-related macular degeneration, while Nag (2015) [56] reported macrophages with abundant irregular lipofuscin loaded-melanosomes of variable size in the aging human choroid, suggesting that damaged melanocytes are cleared by these phagocytes. It is important to highlight that, in all the ages analyzed in our study, macrophages showed significantly higher accumulation of lipofuscin than lymphocytes, which could be explain by the fact that macrophages produced higher levels of ROS than lymphocytes, due to their role in host defense and their high glycolytic metabolism (macrophages display more mitochondrial activity than lymphocytes) [57].…”

Section: Discussionmentioning

confidence: 99%

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Role of macrophages in age-related oxidative stress and lipofuscin accumulation in mice

et al. 2017

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The age-related changes in the immune functions (immunosenescence) may be mediated by an increase of oxidative stress and damage affecting leukocytes. Although the “oxidation-inflammation” theory of aging proposes that phagocytes are the main immune cells contributing to “oxi-inflamm-aging”, this idea has not been corroborated. The aim of this work was to characterize the age-related changes in several parameters of oxidative stress and immune function, as well as in lipofuscin accumulation (“a hallmark of aging”), in both total peritoneal leukocyte population and isolated peritoneal macrophages. Adult, mature, old and long-lived mice (7, 13, 18 and 30 months of age, respectively) were used. The xanthine oxidase (XO) activity-expression, basal levels of superoxide anion and ROS, catalase activity, oxidized (GSSG) and reduced (GSH) glutathione content and lipofuscin levels, as well as both phagocytosis and digestion capacity were evaluated. The results showed an age-related increase of oxidative stress and lipofuscin accumulation in murine peritoneal leukocytes, but especially in macrophages. Macrophages from old mice showed lower antioxidant defenses (catalase activity and GSH levels), higher oxidizing compounds (XO activity/expression and superoxide, ROS and GSSG levels) and lipofuscin levels, together with an impaired macrophage functions, in comparison to adults. In contrast, long-lived mice showed in their peritoneal leukocytes, and especially in macrophages, a well-preserved redox state and maintenance of their immune functions, all which could account for their high longevity. Interestingly, macrophages showed higher XO activity and lipofuscin accumulation than lymphocytes in all the ages analyzed. Our results support that macrophages play a central role in the chronic oxidative stress associated with aging, and the fact that phagocytes are key cells contributing to immunosenescence and “oxi-inflamm-aging”. Moreover, the determination of oxidative stress and immune function parameters, together with the lipofuscin quantification, in macrophages, can be used as useful markers of the rate of aging and longevity.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Role of macrophages in age-related oxidative stress and lipofuscin accumulation in mice

et al. 2017

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“…However, there is a counterargument for the increase in choroidal melanin with aging. A transmission electron microscopy study of aged human choroidal melanocytes showed emptiness in the cytoplasm caused by the loss of melanosomes 31 . Additional histological studies will be required to resolve this controversy about the aging-related changes in choroidal melanin.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of choroidal melanin-containing tissue in healthy Japanese subjects by polarization-sensitive optical coherence tomography

Miura

Makita

Yasuno

et al. 2022

Sci Rep

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In this study, the choroidal melanin content in healthy eyes was evaluated with polarization-sensitive optical coherence tomography (PS-OCT). We evaluated 105 healthy eyes of 105 Japanese subjects. The mean thickness of melanin-containing tissue in the choroid (thickness of MeCh) and the choroidal melanin occupancy rate within a 5-mm circular region from the foveal center were calculated using the degree of polarization uniformity obtained by PS-OCT and compared with the choroidal thickness, patient age, and axial length. To evaluate regional variations, the 5-mm circular region was divided into a center area and an outer ring area, and the outer ring area was further divided into four areas (nasal, temporal, superior, and inferior). The mean thickness of MeCh showed a significant positive correlation with the choroidal thickness. The mean choroidal melanin occupancy rate showed a significant positive correlation with age. The mean choroidal melanin occupancy rate of the center area was significantly larger than that of the outer ring area. The mean thickness of MeCh and choroidal melanin occupancy rate of the nasal area were significantly lower than those of other areas. The distribution of melanin-containing tissue in the choroid varies significantly with age and location.

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“…Tyrosinase catalyses the conversion of L‐tyrosine to dihydroxyphenylalanine (DOPA) and the conversion of DOPA to quinone – two important steps in melanin synthesis that limit the rate of production. As the body ages, the distribution of DOPA‐positive melanocytes becomes less even as their frequency decreases , meaning remaining areas of high melanocyte density are likely sites of discoloured skin. Consequently, a common route of hyperpigmentation treatment is via the inhibition of tyrosinase .…”

Section: Anti‐pigmentation Moleculesmentioning

confidence: 99%

The promise of marine molecules as cosmetic active ingredients

Brunt

Burgess

2017

Intern J of Cosmetic Sci

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The marine environment represents an underexploited resource for the discovery of novel products, despite its high level of biological and chemical diversity. With increasing awareness of the harmful effects of chronic ultraviolet exposure, and a universal desire to improve cosmetic appearance, the market for new cosmetic ingredients is growing, and current trends have generated a greater demand for products sourced from the environment. A growing number of novel molecules from marine flora and fauna exhibit potent and effective dermatological activities. Secondary metabolites isolated from macroalgae, including carotenoids and polyphenols, have demonstrated antioxidant, anti-ageing and anti-inflammatory activities. In addition, marine extremophilic bacteria have recently been shown to produce bioactive exopolymeric molecules, some of which have been commercialized. Available data on their activities show significant antioxidant, moisturizing and anti-ageing activities, but a more focussed investigation into their mechanisms and applications is required. This review surveys the reported biological activities of an emerging and growing portfolio of marine molecules that show promise in the treatment of cosmetic skin problems including ultraviolet damage, ageing and cutaneous dryness.R esum e L'environnement marin repr esente une ressource sous-exploit ee pour la d ecouverte de nouveaux produits, malgr e son niveau elev e de diversit e biologique et chimique. Avec la prise de conscience croissante des effets n efastes de l'exposition chronique aux ultraviolets et un d esir universel d'am eliorer l'apparence, le march e des nouveaux ingr edients cosm etiques est en croissance et les tendances actuelles ont g en er e une plus grande demande pour les produits issus de l'environnement. Un nombre croissant de nouvelles mol ecules issues de la flore et de la faune marines pr esentent des activit es dermatologiques efficaces et performantes. Les m etabolites secondaires isol es des macroalgues, y compris les carot eno€ ıdes et les polyph enols, ont d emontr e des activit es antioxydantes, antivieillissement et anti-inflammatoires. De plus, il a et e d emontr e r ecemment que les bact eries extrêmophiles marines produisent des mol ecules exopolym eriques bioactives, dont certaines ont et e commercialis ees. Les donn ees disponibles sur leurs activit es montrent des activit es antioxydantes, hydratantes et anti-ages significatives, mais une investigation plus cibl ee de leurs m ecanismes et applications est requise. Cette revue etudie les activit es biologiques rapport ees d'une gamme emergente et croissante de mol ecules marines prometteuses, dans le traitement des probl emes de peau cosm etiques, y compris les dommages caus es par les ultraviolets, le vieillissement et la s echeresse cutan ee.

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Ultrastructural changes in the melanocytes of aging human choroid

Cited by 13 publications

References 33 publications

Role of macrophages in age-related oxidative stress and lipofuscin accumulation in mice

Role of macrophages in age-related oxidative stress and lipofuscin accumulation in mice

Evaluation of choroidal melanin-containing tissue in healthy Japanese subjects by polarization-sensitive optical coherence tomography

The promise of marine molecules as cosmetic active ingredients

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