scholarly journals Vitamin A, endocrine tissues and hormones: interplay and interactions

2017 ◽  
Vol 6 (7) ◽  
pp. R121-R130 ◽  
Author(s):  
J Brossaud ◽  
V Pallet ◽  
J-B Corcuff
Keyword(s):  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Therapeutic Use ◽  
Tissue Remodelling ◽  
Pancreatic Development ◽  
Brain Functions ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
And Function ◽  
Endocrine Tissues

Vitamin A (retinol) is a micronutrient critical for cell proliferation and differentiation. In adults, vitamin A and metabolites such as retinoic acid (RA) play major roles in vision, immune and brain functions and tissue remodelling and metabolism. This review presents the physiological interactions of retinoids and endocrine tissues and hormonal systems. Two endocrine systems have been particularly studied. In the pituitary, retinoids target the corticotrophs with a possible therapeutic use in corticotropinomas. In the thyroid, retinoids interfere with iodine metabolism and vitamin A deficiency aggravates thyroid dysfunction caused by iodine-deficient diets. Retinoids use in thyroid cancer appears less promising than expected. Recent and still controversial studies investigated the relations between retinoids and metabolic syndrome. Indeed, retinoids contribute to pancreatic development and modify fat and glucose metabolism. However, more detailed studies are needed before planning any therapeutic use. Finally, retinoids probably play more minor roles in adrenal and gonads development and function apart from their major effects on spermatogenesis.

scholarly journals MicroRNAs in brain development and cerebrovascular pathophysiology

2019 ◽  
Vol 317 (1) ◽  
pp. C3-C19 ◽  
Author(s):  
Qingyi Ma ◽  
Lubo Zhang ◽  
William J. Pearce
Keyword(s):  
Brain Development ◽  
Synapse Formation ◽  
Current Knowledge ◽  
Great Promise ◽  
Ischemic Brain ◽  
Neural Lineage ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
And Function

MicroRNAs (miRNAs) are a class of highly conserved non-coding RNAs with 21–25 nucleotides in length and play an important role in regulating gene expression at the posttranscriptional level via base-paring with complementary sequences of the 3′-untranslated region of the target gene mRNA, leading to either transcript degradation or translation inhibition. Brain-enriched miRNAs act as versatile regulators of brain development and function, including neural lineage and subtype determination, neurogenesis, synapse formation and plasticity, neural stem cell proliferation and differentiation, and responses to insults. Herein, we summarize the current knowledge regarding the role of miRNAs in brain development and cerebrovascular pathophysiology. We review recent progress of the miRNA-based mechanisms in neuronal and cerebrovascular development as well as their role in hypoxic-ischemic brain injury. These findings hold great promise, not just for deeper understanding of basic brain biology but also for building new therapeutic strategies for prevention and treatment of pathologies such as cerebral ischemia.

scholarly journals Timing as a mechanism of development and evolution in the cerebral cortex

2021 ◽  
Author(s):  
Laura R. Fenlon
Keyword(s):  
Phenotypic Variation ◽  
Cognitive Abilities ◽  
Individual Variability ◽  
Cell Proliferation And Differentiation ◽  
Single Organism ◽  
Proliferation And Differentiation ◽  
And Function ◽  
Axonal Targeting ◽  
The Brain ◽  
Development And Evolution

One of the biggest mysteries in neurobiology concerns the mechanisms responsible for the diversification of the brain over different time scales i.e. during development and evolution. Subtle differences in the timing of biological processes during development, e.g. onset, offset, duration, speed and sequence, can trigger large changes in phenotypic outcomes. At the level of a single organism, altered timing of developmental events can lead to individual variability, as well as malformation and disease. At the level of phylogeny, there are known interspecies differences in the timing of developmental events, and this is thought to be an important factor that drives phenotypic variation across evolution, known as heterochrony. A particularly striking example of phenotypic variation is the evolution of human cognitive abilities, which has largely been attributed to the development of the mammalian-specific neocortex and its subsequent expansion in higher primates. Here, I review how the timing of different aspects of cortical development specifies developmental outcomes within species, including processes of cell proliferation and differentiation, neuronal migration and lamination, and axonal targeting and circuit maturation. Some examples of the ways that different processes might “keep time” in the cortex are explored, reviewing potential cell-intrinsic and -extrinsic mechanisms. Further, by combining this knowledge with known differences in timing across species, timing changes that may have occurred during evolution are identified, which perhaps drove the phylogenetic diversification of neocortical structure and function.

Retinoic acid reverses the airway hyperresponsiveness but not the parenchymal defect that is associated with vitamin A deficiency

2004 ◽  
Vol 286 (2) ◽  
pp. L437-L444 ◽  
Author(s):  
Stephen E. McGowan ◽  
Amey Jo Holmes ◽  
Jennifer Smith
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Airway Hyperresponsiveness ◽  
Vitamin A Deficiency ◽  
Elastic Fibers ◽  
Bronchial Wall ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Airway Caliber ◽  
And Function

Airway hyperresponsiveness (AHR) is influenced by structural components of the bronchial wall, including the smooth muscle and connective tissue elements and the neuromuscular function. AHR is also influenced by parenchymally derived tethering forces on the bronchial wall, which maintain airway caliber by producing outward radial traction. Our previous work has shown that vitamin A-deficient (VAD) rats exhibit cholinergic hyperresponsiveness and a decrease in the expression and function of the muscarinic-2 receptors (M2R). We hypothesized that if decreases in radial traction from airway or parenchymal structures contributed to the VAD-related increase in AHR, then the radial traction would normalize more slowly than VAD-related alterations in neurotransmitter signaling. Rats remained vitamin A sufficient (VAS) or were rendered VAD and then maintained on the VAD diet in the presence or absence of supplementation with all- trans retinoic acid (RA). VAD was associated with an approximately twofold increase in respiratory resistance and elastance compared with VAS rats. Exposure to RA for 12 days but not 4 days restored resistance and elastance to control (VAS) levels. In VAD rats, AHR was accompanied by decreases in bronchial M2R gene expression and function, which were restored after 12 days of RA supplementation. Subepithelial bronchial elastic fibers were decreased by ∼50% in VAD rats and were significantly restored by RA. The increase in AHR that is associated with VAD is accompanied by decreases in M2R expression and function that can be restored by RA and a reduction in airway elastic fibers that can be partially restored by RA.

Content of retinol and retinyl esters in blood plasma, liver, kidney and reproductive organs of Japanese quails

2002 ◽  
Vol 50 (4) ◽  
pp. 435-443 ◽  
Author(s):  
Annamária Kerti ◽  
Ingeborg Buchholz ◽  
F. J. Schweigert
Keyword(s):  
Vitamin A ◽  
Blood Plasma ◽  
Reproductive Organs ◽  
Egg Laying ◽  
Dominant Form ◽  
Physiological Processes ◽  
Egg Formation ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Retinyl Esters

Due to its importance in many physiological processes such as cell proliferation and differentiation, vitamin A plays a key role in reproduction. The present study examines the content and distribution of retinol and retinyl esters in the blood plasma, liver, kidney, ovary and oviduct (infundibulum, magnum, isthmus and uterus) of the laying Japanese quail. (1) The results show that the stage of egg laying had no influence on the level of vitamin A (retinol or retinyl esters) in plasma, kidney and liver. (2) The results further indicate that in the oviduct there are quantitative and qualitative differences in the concentration of retinol and retinyl esters, but that these differences are not altered by the stage of egg formation. (3) The highest levels of vitamin A in the isthmus and uterus were associated with a predominance of retinyl esters (palmitate and stearate); sections with lower total levels of vitamin A (infundibulum, magnum) had retinol as the more dominant form of vitamin A. (4) Changes in the ratio of retinol to retinyl esters in the various sections of the avian oviduct might point to metabolic differences. The storage of vitamin A might therefore be the predominant function of the uterus and isthmus; in the infundibulum and magnum, where vitamin A is predominantly present as retinol, vitamin A serves rather as a precursor for the modulation of the cellular metabolism of these structures.

scholarly journals Clinical and Molecular Insights in Erythropoiesis Regulation of Signal Transduction Pathways in Myelodysplastic Syndromes and β-Thalassemia

2021 ◽  
Vol 22 (2) ◽  
pp. 827
Author(s):  
Sarah Parisi ◽  
Carlo Finelli ◽  
Antonietta Fazio ◽  
Alessia De Stefano ◽  
Sara Mongiorgi ◽  
...  
Keyword(s):  
Myelodysplastic Syndromes ◽  
Transforming Growth Factor ◽  
Early Stage ◽  
Hypoxia Inducible Factor ◽  
Phosphatidylinositol 3 Kinase ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
And Function ◽  
Preclinical And Clinical Studies ◽  
Role And Function

Erythropoiesis regulation is essential in normal physiology and pathology, particularly in myelodysplastic syndromes (MDS) and β-thalassemia. Several signaling transduction processes, including those regulated by inositides, are implicated in erythropoiesis, and the latest MDS or β-thalassemia preclinical and clinical studies are now based on their regulation. Among others, the main pathways involved are those regulated by transforming growth factor (TGF)-β, which negatively regulates erythrocyte differentiation and maturation, and erythropoietin (EPO), which acts on the early-stage erythropoiesis. Also small mother against decapentaplegic (SMAD) signaling molecules play a role in pathology, and activin receptor ligand traps are being investigated for future clinical applications. Even inositide-dependent signaling, which is important in the regulation of cell proliferation and differentiation, is specifically associated with erythropoiesis, with phospholipase C (PLC) and phosphatidylinositol 3-kinase (PI3K) as key players that are becoming increasingly important as new promising therapeutic targets. Additionally, Roxadustat, a new erythropoiesis stimulating agent targeting hypoxia inducible factor (HIF), is under clinical development. Here, we review the role and function of the above-mentioned signaling pathways, and we describe the state of the art and new perspectives of erythropoiesis regulation in MDS and β-thalassemia.

scholarly journals Modulation of Intestinal Immune and Barrier Functions by Vitamin A: Implications for Current Understanding of Malnutrition and Enteric Infections in Children

Nutrients ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1128 ◽  
Author(s):  
Pedro de Medeiros ◽  
Daniel Pinto ◽  
Juliana de Almeida ◽  
Juliana Rêgo ◽  
Francisco Rodrigues ◽  
...  
Keyword(s):  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Intestinal Barrier ◽  
Barrier Functions ◽  
Vitamin A Status ◽  
Enteric Infections ◽  
Underlying Mechanisms ◽  
And Function

The micronutrient vitamin A refers to a group of compounds with pleiotropic effects on human health. These molecules can modulate biological functions, including development, vision, and regulation of the intestinal barrier. The consequences of vitamin A deficiency and supplementation in children from developing countries have been explored for several years. These children live in an environment that is highly contaminated by enteropathogens, which can, in turn, influence vitamin A status. Vitamin A has been described to modulate gene expression, differentiation and function of diverse immune cells; however, the underlying mechanisms are not fully elucidated. This review aims to summarize the most updated advances on elucidating the vitamin A effects targeting intestinal immune and barrier functions, which may help in further understanding the burdens of malnutrition and enteric infections in children. Specifically, by covering both clinical and in vivo/in vitro data, we describe the effects of vitamin A related to gut immune tolerance/homeostasis, intestinal barrier integrity, and responses to enteropathogens in the context of the environmental enteric dysfunction. Some of the gaps in the literature that require further research are also highlighted.

scholarly journals Regulation and perturbation of testicular functions by vitamin A

Reproduction ◽  
2002 ◽  
pp. 173-180 ◽  
Author(s):  
G Livera ◽  
V Rouiller-Fabre ◽  
C Pairault ◽  
C Levacher ◽  
R Habert
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Leydig Cells ◽  
Vitamin A Deficiency ◽  
Cell Metabolism ◽  
Biologically Active ◽  
Proliferation And Differentiation ◽  
Beta Receptors ◽  
Alpha Receptors ◽  
Testicular Lesions

In addition to playing a fundamental role in very diverse processes such as vision and the growth and differentiation of numerous types of cell, vitamin A (retinol) and its principal biologically active derivative, retinoic acid, are clearly involved in the regulation of testicular functions in rodents. An excess of vitamin A leads to testicular lesions and spermatogenetic disorders, and a deficiency induces early cessation of spermatogenesis and adversely affects testosterone secretion. Furthermore, mice mutant for retinoic acid alpha receptors and retinoid X beta receptors are sterile. Retinoids appear to exert an action on the three main testicular types of cell (Sertoli, germinal and Leydig cells), as they act on the signalling pathways and Sertoli cell metabolism, and modify numerous factors secreted in Sertoli cells. Retinoids also appear to be necessary for the proliferation and differentiation of A spermatogonia, and for spermiogenesis. In addition, vitamin A deficiency leads to atrophy of the accessory sex organs after decreased testosterone production. Recent studies have shown that retinoids already affect these three types of cell in fetuses. Curiously, the effects of retinoids on fetal and adult testis seem opposed.

Quantification of Vitamin A in Fortified Rapeseed, Groundnut and Soya Oils Using a Simple Portable Device: Comparison to High Performance Liquid Chromatography

2013 ◽  
Vol 83 (2) ◽  
pp. 122-128 ◽  
Author(s):  
Cécile Renaud ◽  
Jacques Berger ◽  
Arnaud Laillou ◽  
Sylvie Avallone
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Vitamin A ◽  
High Performance ◽  
Vitamin A Deficiency ◽  
Developed Countries ◽  
Portable Device ◽  
Least Developed Countries ◽  
Control Food ◽  
Assay Precision

Vitamin A deficiency is still one of the major public health problems in least developed countries. Fortification of vegetable oils is a strategy implemented worldwide to prevent this deficiency. For a fortification program to be effective, regular monitoring is necessary to control food quality in the producing units. The reference methods for vitamin A quantification are expensive and time-consuming. A rapid method should be useful for regular assessment of vitamin A in the oil industry. A portable device was compared to high-performance liquid chromatography (HPLC) for three plant oils (rapeseed, groundnut, and soya). The device presented a good linearity from 3 to 30 mg retinol equivalents per kg (mg RE.kg- 1). Its limits of detection and quantification were 3 mg RE.kg- 1 for groundnut and rapeseed oils and 4 mg RE.kg- 1 for soya oil. The intra-assay precision ranged from 1.48 % to 3.98 %, considered satisfactory. Accuracy estimated by the root mean squares error ranged from 3.99 to 5.49 and revealed a lower precision than HPLC (0.4 to 2.25). Although it offers less precision than HPLC, the device estimates quickly the vitamin A content of the tested oils from 3 or 4 to 15 mg RE.kg- 1.

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