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Nutrients Dec 2019Vitamin A (all--retinol), its active derivatives retinal and retinoic acid, and their synthetic analogues constitute the group of retinoids. It is obtained from diet... (Review)
Review
Vitamin A (all--retinol), its active derivatives retinal and retinoic acid, and their synthetic analogues constitute the group of retinoids. It is obtained from diet either as preformed vitamin A or as carotenoids. Retinal plays a biological role in vision, but most of the effects of vitamin A are exerted by retinoic acid, which binds to nuclear receptors and regulates gene transcription. Vitamin A deficiency is an important nutritional problem, particularly in the developing world. Retinol and carotenoids from diet during pregnancy and lactation influence their concentration in breast milk, which is important in the long term, not only for the offspring, but also for maternal health. In this study, we review the role of vitamin A in mammary gland metabolism, where retinoid signaling is required not only for morphogenesis and development of the gland and for adequate milk production, but also during the weaning process, when epithelial cell death is coupled with tissue remodeling.
Topics: Animals; Carotenoids; Diet; Female; Humans; Lactation; Mammary Glands, Animal; Mammary Glands, Human; Milk, Human; Nutritional Requirements; Pregnancy; Vitamin A; Vitamin A Deficiency; Weaning
PubMed: 31892157
DOI: 10.3390/nu12010080 -
Methods in Enzymology 2022Macrophages are critical players in the development of atherosclerotic lesions, where they promote local and systemic inflammation. Macrophages engulf lipoproteins and...
Macrophages are critical players in the development of atherosclerotic lesions, where they promote local and systemic inflammation. Macrophages engulf lipoproteins and cell debris upon entry into the arterial wall, becoming lipid-laden foam cells. While most lipids found in foam cells are triglyceride and cholesterol, these cells accumulate several other lipids with bioactive properties, such as vitamin A and carotenoids. Vitamin A has strong immunomodulatory actions in macrophages and other immune cells. For example, macrophages release vitamin A as retinoic acid to modulate T cell differentiation, but the implication of intracellular vitamin A stores in this process remains elusive due to the lack of an adequate experimental model to load vitamin A into macrophages. The purpose of this study was to develop a reliable method to deliver vitamin A to cultured murine macrophages. Our results show that thioglycolate-elicited peritoneal macrophages fail to take up significant levels of vitamin A when provided as free retinol. Cultured macrophages and macrophages in the peritoneal cavity can take up retinyl esters, either as retinyl ester-loaded serum or retinyl esters infused directly into the peritoneal cavity. HPLC analyses in macrophage lysates revealed that the intraperitoneal injection method results in a fourfold greater vitamin A loading efficiency than retinyl ester-loaded serum added to cultured cells. These two alternative methods provide an efficient and reliable methodology to load macrophages with vitamin A for downstream applications such as studies of gene regulation trafficking of intracellular vitamin A, and vitamin A release from macrophages.
Topics: Animals; Cells, Cultured; Lipoproteins; Macrophages; Mice; Retinyl Esters; Triglycerides; Vitamin A
PubMed: 36008013
DOI: 10.1016/bs.mie.2022.04.008 -
Developmental Biology Jul 2021Vertebrate rod and cone photoreceptors detect light via a specialized organelle called the outer segment. This structure is packed with light-sensitive molecules known... (Review)
Review
Vertebrate rod and cone photoreceptors detect light via a specialized organelle called the outer segment. This structure is packed with light-sensitive molecules known as visual pigments that consist of a G-protein-coupled, seven-transmembrane protein known as opsin, and a chromophore prosthetic group, either 11-cis retinal ('A') or 11-cis 3,4-didehydroretinal ('A'). The enzyme cyp27c1 converts A into A in the retinal pigment epithelium. Replacing A with A in a visual pigment red-shifts its spectral sensitivity and broadens its bandwidth of absorption at the expense of decreased photosensitivity and increased thermal noise. The use of vitamin A-based visual pigments is strongly associated with the occupation of aquatic habitats in which the ambient light is red-shifted. By modulating the A/A ratio in the retina, an organism can dynamically tune the spectral sensitivity of the visual system to better match the predominant wavelengths of light in its environment. As many as a quarter of all vertebrate species utilize A, at least during a part of their life cycle or under certain environmental conditions. A utilization therefore represents an important and widespread mechanism of sensory plasticity. This review provides an up-to-date account of the A/A chromophore exchange system.
Topics: Animals; Opsins; Photoreceptor Cells, Vertebrate; Retina; Retinal Cone Photoreceptor Cells; Retinal Pigment Epithelium; Retinal Pigments; Retinal Rod Photoreceptor Cells; Rod Opsins; Vitamin A
PubMed: 33684435
DOI: 10.1016/j.ydbio.2021.03.002 -
Developmental Biology Aug 2021Vitamin A deficiency can cause human pathologies that range from blindness to embryonic malformations. This diversity is due to the lack of two major vitamin A... (Review)
Review
Vitamin A deficiency can cause human pathologies that range from blindness to embryonic malformations. This diversity is due to the lack of two major vitamin A metabolites with very different functions: the chromophore 11-cis-retinal (vitamin A aldehyde) is a critical component of the visual pigment that mediates phototransduction, while the signaling molecule all-trans-retinoic acid regulates the development of various tissues and is required for the function of the immune system. Since animals cannot synthesize vitamin A de novo, they must obtain it either as preformed vitamin A from animal products or as carotenoid precursors from plant sources. Due to its essential role in the visual system, acute vitamin A deprivation impairs photoreceptor function and causes night blindness (poor vision under dim light conditions), while chronic deprivation results in retinal dystrophies and photoreceptor cell death. Chronic vitamin A deficiency is the leading cause of preventable childhood blindness according to the World Health Organization. Due to the requirement of vitamin A for retinoic acid signaling in development and in the immune system, vitamin A deficiency also causes increased mortality in children and pregnant women in developing countries. Drosophila melanogaster is an excellent model to study the effects of vitamin A deprivation on the eye because vitamin A is not essential for Drosophila development and chronic deficiency does not cause lethality. Moreover, genetic screens in Drosophila have identified evolutionarily conserved factors that mediate the production of vitamin A and its cellular uptake. Here, we review our current knowledge about the role of vitamin A in the visual system of mammals and Drosophila melanogaster. We compare the molecular mechanisms that mediate the uptake of dietary vitamin A precursors and the metabolism of vitamin A, as well as the consequences of vitamin A deficiency for the structure and function of the eye.
Topics: Animals; Drosophila melanogaster; Mammals; Photoreceptor Cells; Retina; Retinal Pigment Epithelium; Retinaldehyde; Tretinoin; Vision, Ocular; Visual Perception; Vitamin A; Vitamin A Deficiency
PubMed: 33774009
DOI: 10.1016/j.ydbio.2021.03.013 -
Veterinary Medicine and Science Mar 2021The high incidence of disease in captive pangolins is a major obstacle in pangolin-conservation breeding programs. Therefore, elucidating pangolins' susceptibility to...
The high incidence of disease in captive pangolins is a major obstacle in pangolin-conservation breeding programs. Therefore, elucidating pangolins' susceptibility to disease is the key to conservation progress. At the Pangolin Research Base for Artificial Rescue and Conservation Breeding of South China Normal University (PRB-SCNU), vitamin A deficiency was diagnosed in 14 captive Sunda pangolins. Typical eye signs included lacrimal eyes, keratopathy and a blank, milky orb. The afflicted pangolins were treated with vitamins A and D for 15-30 days; all individuals recovered. We report the detection and treatment of vitamin A deficiency in captive Sunda pangolins at the PRB-SCNU. Our results could provide guidance for the future prevention and treatment of vitamin A deficiency and associated diseases in pangolin species, both to reduce the incidence of these diseases in captive pangolins and to aid conservation efforts.
Topics: Animals; Animals, Zoo; China; Conservation of Natural Resources; Pangolins; Vitamin A; Vitamin A Deficiency; Vitamins
PubMed: 33058569
DOI: 10.1002/vms3.367 -
European Journal of Human Genetics :... Dec 2021Congenital diaphragmatic hernia (CDH) is a life-threatening malformation characterised by failure of diaphragmatic development with lung hypoplasia and persistent... (Review)
Review
Congenital diaphragmatic hernia (CDH) is a life-threatening malformation characterised by failure of diaphragmatic development with lung hypoplasia and persistent pulmonary hypertension of the newborn (PPHN). The incidence is 1:2000 corresponding to 8% of all major congenital malformations. Morbidity and mortality in affected newborns are very high and at present, there is no precise prenatal or early postnatal prognostication parameter to predict clinical outcome in CDH patients. Most cases occur sporadically, however, genetic causes have long been discussed to explain a proportion of cases. These range from aneuploidy to complex chromosomal aberrations and specific mutations often causing a complex phenotype exhibiting multiple malformations along with CDH. This review summarises the genetic variations which have been observed in syndromic and isolated cases of congenital diaphragmatic hernia.
Topics: Genetic Testing; Hernia, Diaphragmatic; Humans; Mutation; Vitamin A
PubMed: 34621023
DOI: 10.1038/s41431-021-00972-0 -
Journal of Parkinson's Disease 2021Evidence shows that altered retinoic acid signaling may contribute to the pathogenesis and pathophysiology of Parkinson's disease (PD). Retinoic acid is the bioactive... (Review)
Review
Evidence shows that altered retinoic acid signaling may contribute to the pathogenesis and pathophysiology of Parkinson's disease (PD). Retinoic acid is the bioactive derivative of the lipophilic vitamin A. Vitamin A is involved in several important homeostatic processes, such as cell differentiation, antioxidant activity, inflammation and neuronal plasticity. The role of vitamin A and its derivatives in the pathogenesis and pathophysiology of neurodegenerative diseases, and their potential as therapeutics, has drawn attention for more than 10 years. However, the literature sits in disparate fields. Vitamin A could act at the crossroad of multiple environmental and genetic factors of PD. The purpose of this review is to outline what is known about the role of vitamin A metabolism in the pathogenesis and pathophysiology of PD. We examine key biological systems and mechanisms that are under the control of vitamin A and its derivatives, which are (or could be) exploited for therapeutic potential in PD: the survival of dopaminergic neurons, oxidative stress, neuroinflammation, circadian rhythms, homeostasis of the enteric nervous system, and hormonal systems. We focus on the pivotal role of ALDH1A1, an enzyme expressed by dopaminergic neurons for the detoxification of these neurons, which is under the control of retinoic acid. By providing an integrated summary, this review will guide future studies on the potential role of vitamin A in the management of symptoms, health and wellbeing for PD patients.
Topics: Dopaminergic Neurons; Humans; Neuroinflammatory Diseases; Parkinson Disease; Tretinoin; Vitamin A
PubMed: 34120916
DOI: 10.3233/JPD-212671 -
Biochimica Et Biophysica Acta.... Nov 2020Carotenoids exert a rich variety of physiological functions in mammals and are beneficial for human health. These lipids are acquired from the diet and metabolized to... (Review)
Review
Carotenoids exert a rich variety of physiological functions in mammals and are beneficial for human health. These lipids are acquired from the diet and metabolized to apocarotenoids, including retinoids (vitamin A and its metabolites). The small intestine is a major site for their absorption and bioconversion. From here, carotenoids and their metabolites are distributed within the body in triacylglycerol-rich lipoproteins to support retinoid signaling in peripheral tissues and photoreceptor function in the eyes. In recent years, much progress has been made in identifying carotenoid metabolizing enzymes, transporters, and binding proteins. A diet-responsive regulatory network controls the activity of these components and adapts carotenoid absorption and bioconversion to the bodily requirements of these lipids. Genetic variability in the genes encoding these components alters carotenoid homeostasis and is associated with pathologies. We here summarize the advanced state of knowledge about intestinal carotenoid metabolism and its impact on carotenoid and retinoid homeostasis of other organ systems, including the eyes, liver, and immune system. The implication of the findings for science-based intake recommendations for these essential dietary lipids is discussed. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.
Topics: Animals; Carotenoids; Homeostasis; Humans; Intestinal Absorption; Lipid Metabolism; Lipids; Liver; Triglycerides; Vitamin A
PubMed: 31794861
DOI: 10.1016/j.bbalip.2019.158580 -
International Journal For Vitamin and... Dec 2023
Topics: Antioxidants; Vitamin A; Ascorbic Acid; Vitamin E
PubMed: 35291873
DOI: 10.1024/0300-9831/a000752 -
Nutrients Jun 2021The association between obesity and vitamin A has been studied. Some studies point to the anti-obesity activity related to this vitamin, carotenoids with provitamin A... (Review)
Review
The association between obesity and vitamin A has been studied. Some studies point to the anti-obesity activity related to this vitamin, carotenoids with provitamin A activity, and carotenoid conversion products. This performance has been evaluated in respect of adipogenesis, metabolic activity, oxidation processes, secretory function, and oxidative stress modulation, showing a new property attributed to vitamin A in preventing and treating obesity. However, vitamin A and its precursors are highly sensitive and easily degraded when subjected to heat, the presence of light, and oxygen, in addition to losses related to the processes of digestion and absorption. In this context, encapsulation presents itself as an alternative capable of increasing vitamin A's stability in the face of unfavorable conditions in the environment, which can reduce its functionality. Considering that vitamin A's status shows a strong correlation with obesity and is an innovative theme, this article addresses the associations between vitamin A's consumption and its precursors, encapsulated or not, and its physiological effects on obesity. The present narrative review points out those recent studies that demonstrate that vitamin A and its encapsulated precursors have the most preserved functionality, which guarantees better effects on obesity therapy.
Topics: Carotenoids; Drug Delivery Systems; Humans; Obesity; Vitamin A; Vitamins
PubMed: 34204998
DOI: 10.3390/nu13061921