Retinoids, natural and synthetic signaling molecules that are structurally related to vitamin A. Compounds such as retinol, retinal, retinoic acid, retinyl esters and other derivatives are considered under the group of retinoids. Retinoids are significantly considered to be the most prominent regulators of several essential biological functions. For instance, active derivative of retinol (metabolite of Vitamin A) such as retinoic acid (RA) plays a major role in vision, cell differentiation, tissue homeostasis, apoptosis, organogenesis, regulation of immune system and embryonic pattern formation(1). In addition RA is also considered to be a potent chemopreventive and tumor suppressive agent because of its apoptotic and anti-oxidant activity. A wide variety of studies in animal models and clinical trials have shown the anticancer activity of RA against different types of cancers such as lymphoma, leukemia, melanoma, lung cancer, cervical cancer, kidney cancer, neuroblastoma, and glioblastoma (2). It has also been shown that RA promotes the generation of ROS including free radicals that drives the expression of antioxidant enzymes in rat sertoli cells and human retinal pigment epithelial cells (3) (4). Retinoids induce their physiological effects via interaction with two distinct classes of nuclear receptors including retinoic acid receptors (RAR) and retinoid X receptors (RXR). These two nuclear receptors belong to the members of steroid/thyroid hormone receptor superfamily (5) (6). All-trans-retenoic acid (ATRA) and 9-cis- retenoic acid (9CRA) are the two isomers of RA which acts as ligands and binds to the RAR and RXR nuclear receptors. Although, it’s well known that, 9CRA only binds with RXRs, where as both ATRA and 9CRA ligand... ... middle of paper ... ...tamin A-deficient (VAD) diet to know the specific antagonistic activity of RA on Nrf2. Interestingly, experimental data on western blotting of proteins in the small intestine of Nrf2 +/+ has shown an increase in the levels of Gstm5, GCLC, NQO1 and Gsta1/2 but not in the Nrf2 -/- mice. Moreover, the administration of ATRA to Nrf2 +/+ mice on the VAD diet has shown almost complete blockage in the increase in Gstm5, GCLC, NQO1, and Gsta1/2 proteins in the small intestine. This repression of ARE-driven gene expression strongly suggested the antagonistic role of ATRA on Nrf2. Altogether above findings suggested that, targeting the Nrf2 inhibition through RARα may become a novel therapeutic approach to encounter the drug resistance in tumor cells. However, further structural studies on Nrf2: RARα interactions are needed to know which domain of RARα could reacts with Nrf2.
Dr. Janis Eells presented a study that was accomplished by her and her students under the title “UNBLINDED BY THE LIGHT: Photobiomodulation for the Treatment of Retinal Degenerative Disease”. The purpose of this study is to determine whether photobiomodulation with near-infrared is able to treat retinal degeneration diseases. Thus, they hypothesis that the exposure of a rodent model of methanol toxicity to photobiomodulation (PBM) with near-infrared (NIR) could play a potential role in protecting the retina against the toxic actions of the methanol- derived formic acid. What is known about the topic is that if a small amount of methanol is injected it will rapidly cause permanent blindness. The methanol is metabolized to a mitochondrial toxin, and it is formic acid that can inhibit Cytochrome c Oxidase. This formic acid is able to interrupt mitochondrial function and increases oxidative stress in the retina and optic nerve which eventually leads to blindness. In order to fully test their hypothesis, the rats were randomly divided into four treatment groups: untreated control, LED-treated control, methanol-intoxicated, and LED-treated, methanol-intoxicated rats. they used electroretinogram as a sensitive indicator of retinal function, the experimental rats under methanol intoxication were exposed to three ...
Heaney RP. The vitamin D requirement in health and disease. J Steroid Biochem Mol Biol. 2005;97(1-2):13-19.
The widespread involvement of Retinal Pigment Epithelium (RPE), flat (placoid) nature of the lesions and absence of overlying serous retinal detachment and minimal choroidal involvement lead Gass to conclude RPE was primary focus of inflammation.(1) ...
...s to interfere with bonding to the receptors. The final possibility uses CNP, which downregulates the activation in MAP kinase pathways in the chondrocytes (4).
Rett syndrome is a postnatal neurodevelopmental disorder that mainly affects girls but is rarely found in boys as well. Rett syndrome strikes all racial and ethnic groups, and occurs worldwide in 1 of every 10,000 female births. It was first identified by Dr. Andreas Rett, an Austrian physician who described it in an article published in 1966. Even though Rett described the disorder in his 1966 article it went another 17 years until being generally recognized after Swedish researcher Dr. Bengt Hagberg published an article about the disorder in 1983 (Rett Syndrome Fact Sheet).
...on and forms an inhibitory complex with caveolin-1 leads to decrease in activity of enzyme in the cells. Transcription of Cav-1 gene is regulated by cholesterol responsive elements. Exposure of fibroblast and endothelial cells to free cholesterol and LDL Cholesterol was found to up regulate Cav-1 expression. Ca+2 mobilizing agents cause disinhibiton of e NOS by promoting Ca+2/Calmodulin triggered dissociation of Cav-1.
..., t. t. (n.d.). Menopausal Hormone Replacement Therapy Use and Cancer - National Cancer Institute. Comprehensive Cancer Information - National Cancer Institute. Retrieved September 19, 2011, from http://www.cancer.gov/cancertopics/factsheet/Risk/menopausal-hormones/print
Another study proposed that CR slowed aging process by increasing resistance to hyperoxidation. As aging progressed in yeast and other animals, the presence of free radicals increased in the cells. Usually, the levels of the...
Retinoids are vitamin A derivatives. They help to regulate differentiation and cell proliferation. Higher expression of retinoid signaling takes place in neuronal plasticity areas such as the hippocampus, retrosplenial, and prefrontal cortex (2). Retinoid signaling in the brain helps to control the brain functions. These include neurotransmitter release, neuronal differentiation, neurite growth, and long term potentiation (3). Retinoids are mediated by nuclear receptors (4). These nuclear receptors include retinoic acid receptors α, β, γ, and retinoid x receptors α, β, and γ.
Vitamin D is derived from a steroid; the structure retains its numbering from the parent compound cholesterol.3
This disease is characterized by autoantibodies against intrinsic factor producing cells in the stomach (atrophic gastritis). Intrinsic factor is an important molecule that binds to vitamin B12 in the stomach, allowing the vitamin B12/intrinsic factor complex to become absorbed in the small intestine. Other disorders associated with B12 deficiency include celiac disease and inflammatory bowel disease – this occurs as a result of malabsorption. Individuals that have undergone bowel resection of the stomach or small intestine (e.g., ileum) are also at increased risk.
Vitamin E in all its forms, functions predominantly as an antioxidant by protecting cells from free radicals in the body. Vitamin E works as an antioxidant by donating a hydrogen atom from a hydroxyl group to a free radical within the body. Vitamin E also plays a role in immune system function and protects cell membranes and regulation of gene expression. Vitamin E has been studied to uncover other medical usages, including prevention or treatment of many health conditions [1].
Flavonoids are widely distributed in plants, fulfilling many functions. Flavonoids are the most important in plant pigments for flower coloration, producing yellow, red, or blue pigmentation in plants designed to attract pollinators. In higher plants, flavonoids are involved in UV filtration, symbiotic nitrogen fixation and floral pigmentation. They may also act as chemical messengers, physiological regulators, and cell cycle inhibitors. Flavonoids, which are polyphenolic compounds, are a class of plant secondary metabolites possessing a broad spectrum of pharmacological activity including anti-cancer activities. Among the various natural products, flavonoids have attracted much attention due to their remarkable spectrum of pharmacological activities such as antioxidant, antimutagenic, antibacterial, antiangiogenic,anti-inflammatory, antiallergic, modulators of enzymatic activities and anti-cancer activity. Flavonoids have been found act as protein kinase inhibitors which can prevent alterations in phosphorylation that result in uncontrolled cell division, inhibition of apoptosis, and other abnormalities. Flavonoids can be known as angiogenesis agents. Angiogenesis is a physiological process resulting in formation of new blood vessels from pre-existing vessels. Antigiogenesis cause rapid growth of solid tumor and tumor metasta-sis are promoted by uncontrolled tumor angiogenesis. The flavonoids can control this growth of tumor. Besides that, flavonoids also can act as antioxidants which known as substances that delay, prevent or remove oxidative damage to a target molecule (Ravishankar et al., 2013).
Tomatoes are nutritious and provide good quantities of vitamins A and C. These vitamins also called antioxidants fight off the effects of free ra...
Vitamins, a group of organic substances required in our diets in small amounts for growth and nutrition, are usually found in foodstuffs or taken as supplements. Yet vitamins probably present a wider gap between myth and reality in the layman's understanding than almost any other area of our diet. Surveys have found that while a majority of Americans do take vitamin supplements on a regular or occasional basis for reason of health concerns, there exists enormous confusion about the actual purpose and benefits of this practice ("Use of Vitamin and Mineral Supplements in the United States," 1990:161). Most people have a recognition that Vitamin C prevents scurvy, that Vitamin A is found in fish-liver oils, or that Vitamin D is found in dairy products; many people believe that Vitamin E preserves youth and prevents sterility, or that Vitamin C can present colds and cancer. Beyond this, however, there is still considerable ignorance and widespread myth.