Melatonin elevates apoptosis in human platelets via ROS mediated mitochondrial damage. Biochem Biophys Res Commun 2013 Aug 16;438(1):198-204
Date
07/25/2013Pubmed ID
23880341DOI
10.1016/j.bbrc.2013.07.053Scopus ID
2-s2.0-84881552543 (requires institutional sign-in at Scopus site) 68 CitationsAbstract
Melatonin is a pineal hormone that regulates circadian and seasonal rhythms. The chronobiotic role of melatonin corresponds with a repertoire of pharmacological properties. Besides, it has a wide range of therapeutic applications. However, recent studies have demonstrated its direct interaction with platelets: at physiological concentration it promotes platelet aggregation; on the other hand, at pharmacological doses it raises intracellular Ca(2+) leading to platelet activation, thrombus formation and cardiovascular disorders. In order to further probe its effects on platelets, the current study targeted platelet apoptosis and melatonin was found to stimulate apoptosis. The mitochondrial pathway of apoptosis was mainly investigated because of its susceptibility to oxidative stress-inducing factors including therapeutic and dietary elements. Melatonin significantly increased the generation of intracellular ROS and Ca(2+), facilitating mitochondrial membrane depolarization, cytochrome c release, caspase activation, protein phosphorylation and phosphatidylserine externalization. Further, the overall toxicity of melatonin on platelets was confirmed by MTT and lactate dehydrogenase assays. The elevated rate of platelet apoptosis has far reaching consequences including thrombocytopenia. Besides, platelets undergoing apoptosis release microparticles, which fuel thrombus formation and play a significant role in the pathophysiology of a number of diseases. In many parts of the world melatonin is an over-the-counter dietary supplement and alternative medicine. Since, melatonin displays platelet proapoptotic effect at a concentration attainable through therapeutic dosage, the present study sends a warning signal to the chronic use of melatonin as a therapeutic drug and questions its availability without a medical prescription.
Author List
Girish KS, Paul M, Thushara RM, Hemshekhar M, Shanmuga Sundaram M, Rangappa KS, Kemparaju KAuthor
Manoj Paul PhD Postdoctoral Researcher 1 in the Surgery department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
ApoptosisBlood Platelets
Cells, Cultured
Humans
Hydrogen Peroxide
Melatonin
Mitochondria
Reactive Oxygen Species