Melatonin elevates apoptosis in human platelets via ROS mediated mitochondrial damage.

Area of Science:

• Biochemistry
• Pharmacology
• Hematology

Background:

• Melatonin is a pineal hormone regulating circadian rhythms with diverse pharmacological properties.
• While beneficial in some contexts, melatonin interacts with platelets, potentially causing adverse cardiovascular effects at pharmacological doses.
• Platelet apoptosis and its role in thrombus formation and disease pathophysiology require further investigation.

Purpose of the Study:

• To investigate the effect of melatonin on platelet apoptosis.
• To elucidate the mitochondrial pathway involved in melatonin-induced platelet apoptosis.
• To assess the safety and implications of melatonin's pro-apoptotic effects on platelets.

Main Methods:

• Melatonin treatment of platelets.
• Assessment of apoptosis markers: intracellular reactive oxygen species (ROS), calcium (Ca2+), mitochondrial membrane potential, cytochrome c release, caspase activation, protein phosphorylation, and phosphatidylserine externalization.
• Cell viability assays: MTT and lactate dehydrogenase (LDH) release.

Main Results:

• Melatonin significantly increased platelet apoptosis via the mitochondrial pathway.
• Elevated intracellular ROS and Ca2+ levels were observed, leading to mitochondrial dysfunction.
• Melatonin-induced apoptosis was confirmed by various assays, indicating overall platelet toxicity.

Conclusions:

• Melatonin exhibits a pro-apoptotic effect on platelets at concentrations achievable through therapeutic use.
• Chronic melatonin use may increase the risk of thrombocytopenia and cardiovascular disorders.
• The availability of melatonin as an over-the-counter supplement warrants caution and further medical scrutiny.