Melatonin: A novel protective agent against oxidative injury of the ischemic/reperfused heart
Russel J. Reiter,Dun Xian Tan +1 more
TLDR
This brief review summarizes the recently obtained evidence which illustrates the beneficial effects of the endogenously produced antioxidant, melatonin, in reducing tissue damage and reversing cardiac pathophysiology in models of experimental ischemia/reperfusion in humans.Abstract:
This brief review summarizes the recently obtained evidence which illustrates the beneficial effects of the endogenously produced antioxidant, melatonin, in reducing tissue damage and reversing cardiac pathophysiology in models of experimental ischemia/reperfusion. The report also describes the actions of other antioxidants, especially vitamin E and antioxidative enzymes, in altering the degree of ischemia/reperfusion damage in the heart. Based on the data available, melatonin seems to have advantages over other antioxidants tested in terms of ameliorating the hypoxia and reoxygenation-induced damage. While the bulk of the studies that have used melatonin to overcome cardiac injury following transient arterial occlusion and subsequent reperfusion have used pharmacological doses to achieve protection, two recent reports have further shown that merely reducing endogenous circulating concentrations of melatonin (by surgical removal of a source of melatonin, i.e. the pineal gland) exaggerates the degree of injury and reduces survival of animals as a result of induced ischemia/reperfusion of the heart. These findings are consistent with observations in other organs where the loss of physiological concentrations of melatonin results in increased oxidative damage during hypoxia and reoxygenation. These findings have implications for the elderly since in the aged endogenous levels of melatonin are naturally reduced thereby possibly predisposing them to more severe cardiac damage during a heart attack. To date, the bulk of the studies relating to the protective actions of melatonin in reducing cardiac ischemia/reperfusion injury have used the rat as the experimental model. Considering the high efficacy of melatonin in limiting ischemia/reperfusion damage as well as melatonin's low toxicity, the studies should be expanded to include other species and models of cardiac ischemia/reperfusion. The results of these investigations would help to clarify the potential importance of the use of melatonin in situations of oxidative damage to the heart in humans.read more
Citations
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Regulation of antioxidant enzymes: a significant role for melatonin.
Carmen Rodríguez,Juan C. Mayo,Rosa M. Sainz,Isaac Antolín,Federico Herrera,Vanesa Martín,Russel J. Reiter +6 more
TL;DR: This report reviews the studies which document the influence of melatonin on the activity and expression of the antioxidative enzymes glutathione peroxidase, superoxide dismutases and catalase both under physiological and under conditions of elevated oxidative stress and analyses the possible mechanisms by which melatonin regulates these enzymes.
Journal ArticleDOI
Oxidative stress impairs oocyte quality and melatonin protects oocytes from free radical damage and improves fertilization rate.
Hiroshi Tamura,Akihisa Takasaki,Ichiro Miwa,Ken Taniguchi,Ryo Maekawa,Hiromi Asada,Toshiaki Taketani,Aki Matsuoka,Yoshiaki Yamagata,Katsunori Shimamura,Hitoshi Morioka,Hitoshi Ishikawa,Russel J. Reiter,Norihiro Sugino +13 more
TL;DR: It is concluded that oxidative stress causes toxic effects on oocyte maturation and melatonin protects oocytes from oxidative stress and is likely to improve oocyte quality and fertilization rates.
Journal ArticleDOI
Melatonin as an antioxidant: biochemical mechanisms and pathophysiological implications in humans.
TL;DR: Melatonin's functions as an antioxidant include: a), direct free radical scavenging, b), stimulation of antioxidative enzymes, c), increasing the efficiency of mitochondrial oxidative phosphorylation and reducing electron leakage (thereby lowering free radical generation), and 3), augmenting the efficiencyof other antioxidants.
Journal Article
Melatonin as an antioxidant: Biochemical mechanisms and pathophysiological implications
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Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases
TL;DR: The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular reactive oxygen species (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive as discussed by the authors.
References
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Myocardial reperfusion: a double-edged sword?
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Actions of melatonin in the reduction of oxidative stress
TL;DR: Melatonin was discovered to be a direct free radical scavenger less than 10 years ago and besides its ability to directly neutralize a number of free radicals and reactive oxygen and nitrogen species, it stimulates several antioxidative enzymes which increase its efficiency as an antioxidant.
Journal ArticleDOI
Chemical and physical properties and potential mechanisms: melatonin as a broad spectrum antioxidant and free radical scavenger.
Dun Xian Tan,Russel J. Reiter,Lucien C. Manchester,Mei ting Yan,Mamdouh R. El-Sawi,Rosa M. Sainz,Juan C. Mayo,Ron Kohen,Mario Allegra,Rudiger Hardeland +9 more
TL;DR: Under in vivo conditions, melatonin is often several times more potent than vitamin C and E in protecting tissues from oxidative injury when compared at an equivalent dosage (micromol/kg).