4236 Malondialdehyde Malondialdehyde is a uremic toxin. Uremic toxins can be subdivided into three major groups based upon their chemical and physical characteristics: 1) small, water-soluble, non-protein-bound compounds, such as urea; 2) small, lipid-soluble and/or protein-bound compounds, such as the phenols and 3) larger so-called middle-molecules, such as beta2-microglobulin. Chronic exposure of uremic toxins can lead to a number of conditions including renal damage, chronic kidney disease and cardiovascular disease. Malondialdehyde (MDA) is the dialdehyde of malonic acid and a biomarker of oxidative damage to lipids caused by smoking. Oxidized lipids are able to produce MDA as a decomposition product. The mechanism is thought to involve formation of prostaglandin-like endoperoxides from polyunsaturated fatty acids with two or more double bonds. An alternative mechanism is based on successive hydroperoxide formation and _-cleavage of polyunsaturated fatty acids. MDA is then directly formed by _-scission of a 3-hydroperoxyaldehyde or by reaction between acrolein and hydroxyl radicals. While oxidation of polyunsaturated fatty acids is the major source of MDA in vivo, other minor sources exists such as byproducts of free radical generation by ionizing radiation and of the biosynthesis of prostaglandins. Aldehydes are generally reactive species capable of forming adducts and complexes in biological systems and MDA is no exception although the main species at physiological pH is the enolate ion which is of relative low reactivity. Consistent evidence is available for the reaction between MDA and cellular macromolecules such as proteins, RNA and DNA. MDA reacts with DNA to form adducts to deoxyguanosine and deoxyadenosine which may be mutagenic and these can be quantified in several human tissues. Oxidative stress is an imbalance between oxidants and antioxidants on a cellular or individual level. Oxidative damage is one result of such an imbalance and includes oxidative modification of cellular macromolecules, induction of cell death by apoptosis or necrosis, as well as structural tissue damage. Chemically speaking, oxidants are compounds capable of oxidizing target molecules. This can take place in three ways: abstraction of hydrogen, abstraction of electrons or addition of oxygen. All cells living under aerobic conditions are continuously exposed to a large numbers of oxidants derived from various endogenous and exogenous sources. The endogenous sources of oxidants are several and include the respiratory chain in the mitochondria, immune reactions, enzymes such as xanthine oxidase and nitric oxide synthase and transition metal mediated oxidation. Various exogenous sources of ROS also contribute directly or indirectly to the total oxidant load. These include effects of ionizing and non-ionizing radiation, air pollution and natural toxic gases such as ozone, and chemicals and toxins including oxidizing disinfectants. A poor diet containing inadequate amounts of nutrients may also indirectly result in oxidative stress by impairing cellular defense mechanisms. The cellular macromolecules, in particular lipids, proteins and DNA, are natural targets of oxidation. Oxidants are capable of initiating lipid oxidation by abstraction of an allylic proton from a polyunsaturated fatty acid. This process, by multiple stages leading to the formation of lipid hydroperoxides, is a known contributor to the development of atherosclerosis. (A3296). 542-78-9 10964 C3H4O2 White powder. 72°C Endogenous, Ingestion, Dermal (contact) Uremic toxins such as malondialdehyde are actively transported into the kidneys via organic ion transporters (especially OAT3). Increased levels of uremic toxins can stimulate the production of reactive oxygen species. This seems to be mediated by the direct binding or inhibition by uremic toxins of the enzyme NADPH oxidase (especially NOX4 which is abundant in the kidneys and heart) (A7868). Reactive oxygen species can induce several different DNA methyltransferases (DNMTs) which are involved in the silencing of a protein known as KLOTHO. KLOTHO has been identified as having important roles in anti-aging, mineral metabolism, and vitamin D metabolism. A number of studies have indicated that KLOTHO mRNA and protein levels are reduced during acute or chronic kidney diseases in response to high local levels of reactive oxygen species (A7869). Uremic toxins tend to accumulate in the blood either through dietary excess or through poor filtration by the kidneys. Most uremic toxins are metabolic waste products and are normally excreted in the urine or feces. 3, not classifiable as to its carcinogenicity to humans. (L135) Naturally produced by the body (endogenous). Chronic exposure to uremic toxins can lead to a number of conditions including renal damage, chronic kidney disease and cardiovascular disease. As a uremic toxin, this compound can cause uremic syndrome. Uremic syndrome may affect any part of the body and can cause nausea, vomiting, loss of appetite, and weight loss. It can also cause changes in mental status, such as confusion, reduced awareness, agitation, psychosis, seizures, and coma. Abnormal bleeding, such as bleeding spontaneously or profusely from a very minor injury can also occur. Heart problems, such as an irregular heartbeat, inflammation in the sac that surrounds the heart (pericarditis), and increased pressure on the heart can be seen in patients with uremic syndrome. Shortness of breath from fluid buildup in the space between the lungs and the chest wall (pleural effusion) can also be present. Kidney dialysis is usually needed to relieve the symptoms of uremic syndrome until normal kidney function can be restored. 2014-08-29T05:50:41Z 2026-05-14T17:47:53Z Malondialdehyde C19440 566274 DB03057 MDD true O=CCC=O C3H4O2 InChI=1S/C3H4O2/c4-2-1-3-5/h2-3H,1H2 WSMYVTOQOOLQHP-UHFFFAOYSA-N 72.0627 72.021129372 Endogenous Solid -0.65 HMDB06112 CHEMBL446036 10499 <p>Dietrich Mangold, Josef Wahl, Wolf-Karlo Aders, &#8220;Preparation of acetals of malonaldehyde.&#8221; U.S. Patent US4410733, issued November, 1976.</p> CHEM003142 DTXSID90202556 propanedial 34.14 17.137 6.419189938704783 2 2 0 6.681544640809551 -6.809543765546642 -1 0 0.10 0.52 2.41e+02 g/l