Supplementary taurine may stabilize atheromatous plaque by antagonizing the activation of metalloproteinases by hypochlorous acid.
The rupture of atherosclerotic plaque, responsible for triggering the majority of myocardial infarctions, presumably requires proteolysis of collagen fibers and other protein components of the intercellular matrix. This is achieved by activated matrix metalloproteases (MMPs) secreted by intimal macrophages and foam cells. MMPs are synthesized as inactive pro-enzymes in which coordinate binding of the thiol group of a key cysteine residue to the active-site zinc atom blocks proteolytic activity. Physiological activation of MMPs is mediated, in large measure, by phagocyte-derived hypochlorous acid (HOCL), which can oxidize the zinc-bound thiol to sulfinic acid, thus freeing the active-site zinc. HOCL also encourages proteolysis of ground substance by inactivating proteins such as TIMP-1 that are physiological inhibitors of MMPs. In vivo, the unrestrained oxidant activity of HOCL is opposed by taurine, which reacts spontaneously with HOCL to generate taurine chloramine, much more stable than HOCL. Taurine chloramine has less impact than HOCL on MMP activation, and does not impair the activity of TIMP-1. Since tissue levels of taurine can be boosted via supplementation, taurine may thus have potential for stabilizing plaque and thereby warding off infarction--an effect that should be reinforced by taurine's platelet-stabilizing activity. In light of recent epidemiological evidence that increased expression of myeloperoxidase - the enzyme which generates HOCL--is an important risk factor for coronary disease, supplemental taurine may indeed have broader utility for suppressing both the genesis and the rupture of atherosclerotic plaque.
Pantox Laboratories, 4622 Santa Fe St., San Diego, CA 92109, USA. mccarty@pantox.com
Mark F
MF
McCarty
D001161:Arteriosclerosis / Q000150:complications / Q000378:metabolism* / Q000517:prevention & control*; D016893:Carotid Stenosis / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control; D019587:Dietary Supplements; D004789:Enzyme Activation; D006801:Humans; D006997:Hypochlorous Acid / Q000378:metabolism*; D045726:Metalloproteases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D008954:Models, Biological; D013654:Taurine / Q000008:administration & dosage*
D013654:Taurine; D006997:Hypochlorous Acid; D045726:Metalloproteases