Hospital Universitario de Canarias, Department of Cardiology, Tenerife, Spain.
Front Biosci (Landmark Ed). 2012 Jun 1;17(7):2433-41. doi: 10.2741/4063.
Melatonin, a circadian hormone with marked antioxidant properties, has been shown to protect against ischemia-reperfusion myocardial damage, especially when administered during reperfusion period. Melatonin has cardioprotective properties via its direct free radical scavenging and its indirect antioxidant activity. Melatonin efficiently interacts with various reactive oxygen and reactive nitrogen species and it also upregulates antioxidant enzymes and downregulates pro-oxidant enzymes. In addition, melatonin demonstrated blood pressure lowering, lipid profile normalizing and anti-inflammatory properties. The lack of these cardioprotective effects due to insufficient melatonin levels might be associated with several cardiovascular pathologies including ischemic heart disease. Patients with acute coronary syndrome or after myocardial infarction were shown to have reduced nighttime melatonin levels and 6-sulfatoxymelatonin urinary excretion. These alterations might translate to increased cardiovascular risk observed in acute myocardial infarction patients with low melatonin levels; and a mutation in melatonin receptors might augment the risk for acute myocardial infarction. Therefore, it is expected that melatonin administration could play a clinically relevant role in the pharmacotherapy of ischemic heart disease; an assumption supported by low toxicity and high safety of melatonin.
褪黑素是一种具有明显抗氧化特性的昼夜节律激素，已被证明可预防缺血再灌注心肌损伤，尤其是在再灌注期间给药时。褪黑素通过直接清除自由基和间接抗氧化活性具有心脏保护作用。褪黑素能有效地与各种活性氧和活性氮物质相互作用，还能上调抗氧化酶，下调促氧化剂酶。此外，褪黑素还具有降低血压、正常化血脂和抗炎作用。由于褪黑素水平不足而缺乏这些心脏保护作用可能与包括缺血性心脏病在内的几种心血管疾病有关。患有急性冠状动脉综合征或心肌梗死后的患者夜间褪黑素水平和 6-硫酸褪黑素尿排泄降低。这些变化可能导致急性心肌梗死患者中观察到的心血管风险增加；而褪黑素受体的突变可能会增加急性心肌梗死的风险。因此，预计褪黑素给药可能在缺血性心脏病的药物治疗中发挥重要的临床作用；这一假设得到了褪黑素低毒性和高安全性的支持。
